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All Rights Reserved,SBC-KSA.The right to use this to grant this right to other party, SADAD 116144000115331 Date 10/23/2018
 Saudi Building Code for Masonry Structures
SBC 305
Key List of the Saudi Codes: Designations and brief
titles
Title Code Req.1 Code & Com.2 Arabic Prov. 3
The General Building Code SBC 201-CR SBC 201-CC SBC 201-AR
Structural – Loading and Forces SBC 301-CR SBC 301-CC SBC 301-AR
Structural – Construction SBC 302- CR SBC 302-AR
Structural – Soil and Foundations SBC 303- CR SBC 303-CC SBC 303-AR
Structural – Concrete Structures SBC 304- CR SBC 304-CC SBC 304-AR
Structural – Masonry
SBC 305-CR SBC 305-CC SBC 305-AR
Structures
Structural – Steel Structures
Electrical Code SBC 401-CR SBC 401-AR
Mechanical Code SBC 501- CR SBC 501-CC SBC 501-AR
Energy Conservation-
SBC 601- CC SBC 601- AR
Nonresidential
Energy Conservation-Residential SBC 602- CC SBC 602- AR
Plumbing Code SBC 701- CR SBC 701-CC SBC 701-AR
Private sewage Code SBC 702- CR SBC 702-AR
Fire Code SBC 801- CR SBC 801-CC SBC 801-AR
Existing Buildings Code SBC 901- CR SBC 901-CC SBC 901-AR
Green Construction Code SBC 1001- CR SBC 1001-CC SBC 1001-AR
Residential Building Code* SBC 1101- CR SBC 1101-CC SBC 1101-AR
Fuel Gas Code* SBC 1201- CR SBC 1201-CC SBC 1201-AR
1. CR: Code Requirements without Commentary
2. CC: Code Requirements with Commentary
3. AR: Arabic Code Provisions
* Under Development

COPYRIGHT © 2018
by
The Saudi Building Code National Committee (SBCNC).

ALL RIGHTS RESERVED. All intellectual property rights of this Saudi Code is owned by the
National Committee of Saudi Building Code as per the regulations of the intellectual property system
in the Kingdom of Saudi Arabia. No part of this code may be reproduced, distributed or leased in any
form or by any means, including but not limited to publishing on cloud sites, computer networks or
any electronic means of communication, without prior written permission from the National
Committee for the Saudi Building Code. The purchase of an electronic or paper copy does not
exempt the individual or entity from complying with the above limitations.

SBC 305-CR- i
 TECHNICAL COMMITTEE (SBC 305):
1 Prof. Magdy Kamel Moustafa Chairman
2 Dr. Ali H. Altheeb Member
3 Dr. Ahmed K. El-Sayed Member
4 Dr. Aref Abadel Member
5 Dr. Fahid Aslam Member

REVIEW COMMITTEE:
1 Dr. Naif M. Alabbadi Chairman
2 Dr. Khaled M. Aljammaz Member
3 Dr. Abdulrahman G. Al-enizi Member
4 Eng. Saeed K. Kadasah Member
5 Eng. Tawifik I. Aljrayed Member

TECHNICAL EDITING COMMITTEE:

1 Prof. Ahmed B. Shuraim Chairman
2 Dr. Abdallah M. Al-Shehri Member
3 Eng. Tawifik I. Aljrayed Member

EDITORIAL SUPPORT:
Prof. Nadeem A. Siddiqui Dr. Ali H. Altheeb
SAUDI BUILDING CODE NATIONAL COMMITTEE (SBCNC):
H. E. Dr. Saad O. AlKasabiChairman
Dr. Naif M. AlabbadiVice Chairman
Dr. Abdulrahman G. Al-eniziMember
Engr. Saeed K. KadasahMember
Dr. Hassan S. AlhazmiMember
Engr. Badr S. AL-maayoofMember
Engr. Fayez A. AlghamdiMember
Engr. Mohammed A. AlwailyMember
Dr. Bandar S. AlkahlanMember
Engr. Ahmad N. HassanMember
Engr. Abdulnasser S. AlabdullatifMember
Dr. Hani M. ZahranMember
Engr. Khalifa S. AlyahyaiMember
Dr. Khaled M. AljammazMember
Dr. Ibrahim O. HabiballahMember
Dr. Saeed A. AsiriMember
Dr. Abdallah COMMITTEE
ADVISORY M. Al-ShehriMember
:
Engr. Saad S. ShuailMember
1 Dr. Khaled M. Aljammaz Chairman
2 Eng. Khalifa S. Alyahyai Vice Chairman
3 Dr. Hani M. Zahran Member
4 Prof. Ali A. Shash Member
5 Prof. Ahmed B. Shuraim Member
6 Dr. Khalid M. Wazira Member
7 Dr. Abdulhameed A. Al Ohaly Member
8 Dr. Hamza A. Ghulman Member
9 Engr. Hakam A. Al-Aqily Member
10 Prof. Saleh F. Magram Member
11 Engr. Nasser M. Al-Dossari Member
12 Dr. Waleed H. Khushefati Member
13 Dr. Waleed M. Abanomi Member
14 Dr. Fahad S. Al-Lahaim Member

SBC 305-CR- i
PREFA

PREFACE

The Saudi Building Code for Masonry Structures (SBC 305) provides minimum requirements for the
structural design and construction of masonry elements consisting of masonry units bedded in
mortar. The first edition of SBC 305 was published in the year of 2007. SBC 305-18 is the second
edition SBC 305 and addresses the structural design of both structural and non-structural masonry
elements. The nonstructural elements are primarily masonry veneer, glass unit masonry, and
masonry partitions. Structural design aspects of non-structural masonry elements include, but are not
limited to, gravity and lateral support, and load transfer to supporting elements. The requirements
provided in SBC 305 are related to contract documents; quality assurance; materials; placement of
embedded items; analysis and design; strength and serviceability; flexural and axial loads; shear;
details and development of reinforcement; walls; columns; pilasters; beams and lintels; seismic
design requirements; glass unit masonry; and veneers. An empirical design method applicable to
buildings meeting specific location and construction criteria is also included in this Code.

The current edition of the Code has been substantially reorganized and reformatted relative to its
2007 edition. The code is reorganized into five parts, 14 chapters and six appendices. The
reorganization was in response to past requests concerning the difficulty in finding provisions. The
new layout is more user-friendly and will better facilitate the use of the design provisions.

ACI 530/530.1-13 is the base code in the development of this Code. Saudi Building Code National
Committee (SBCNC) has made an agreement with the ACI to use their materials and modify them as
per the local construction needs and regulatory requirements of Saudi Arabia. ACI is not responsible
for any modifications or changes the SBCNC has made to accommodate local conditions.

The writing process of SBC 305-18 followed the methodology approved by the Saudi Building Code
National Committee. Many changes and modifications were made in its base code (ACI 530/530.1-
13) to meet the local weather, materials, construction and regulatory requirements.

The committees responsible for SBC 305 Code have taken all precautions to avoid ambiguities,
omissions, and errors in the document. Despite these efforts, the users of SBC 305 may find
information or requirements that may be subject to more than one interpretation or may be
incomplete. The SBCNC alone possesses the authority and responsibility for updating, modifying
and interpreting the Code.

It is a common assumption that engineering knowledge is a prerequisite in understanding code

provisions and requirements; thus, the code is oriented towards individuals who possess the

SBC 305-CR- i
PREFA

background knowledge to evaluate the significance and limitations of its content and
recommendations. They shall be able to determine the applicability of all regulatory limitations
before applying the Code and must comply with all applicable laws and regulations.

The requirements related to administration and enforcement of this Code are advisory only. SBCNC
and governmental organizations, in charge of enforcing this Code, possess the authority to modify
these administrative requirements.

SBC 305-CR- i
SUMMARY OF

SUMMARY OF CHAPTERS

The entire SBC 305-18 is divided into 14 chapters and six appendices. A brief outline of these
chapters and appendices is given below:

Chapter 1. General Requirements—This chapter includes a number of provisions that explain

where SBC 305 Code applies and how it is to be interpreted. It also lists some of the important items
of information that must be included in the project drawings or project specifications. All the
Standards, or specific sections thereof, cited in this Code, including Appendices, are also listed in
this chapter.

Chapter 2. Notation and Definitions—This chapter lists all the notations that were used in the
Code and Commentary. The various terminologies used in the Code are also defined in this chapter.

Chapter 3. Quality and Construction—This chapter provides the details of a quality assurance
program by which the quality of masonry construction is monitored. This chapter is very important
because masonry design provisions in the Code are valid when the quality of masonry construction
meets or exceeds that described in the specification.

Chapter 4. General Analysis and Design Considerations— In this chapter requirements of

design loads, structural analysis procedures, material properties, and section properties are provided
to transfer forces safely from the point of application to the final point of resistance. The chapter also
explicitly emphasizes that masonry walls shall not be connected to structural frames unless the
connections and walls are designed to resist design interconnecting forces and to accommodate
calculated deflections.

Chapter 5. Structural Elements—This chapter provides the requirements for the design of
masonry assemblies, beams, columns, pilasters, and corbels.

Chapter 6. Reinforcement, Metal Accessories, and Anchor Bolts—The requirements for steel
reinforcement, metal accessories and anchor bolts are provided in this chapter. Requirements of
reinforcement and metal accessories include requirements related to embedment, size of
reinforcement, placement of reinforcement, protection of reinforcement and metal accessories,
standard hooks, and bend diameter for reinforcing bars. The requirements for headed and bent-bar
anchor bolts are also provided under the heading of Anchor Bolts.

Chapter 7. Seismic Design Requirements—This chapter provides requirements for the design
and construction of masonry assigned to seismic loads. The requirements of this chapter do not apply
to the design or detailing of masonry veneers or glass unit masonry systems. Seismic requirements
for

SBC 305-CR- v
SUMMARY OF

masonry veneers are provided in Chapter 12. Glass unit masonry systems, by definition and design,
are isolated, non-load-bearing elements and therefore cannot be used to resist seismic loads other
than those induced by their own mass.

Chapter 8. Allowable Stress Design of Masonry—This chapter provides requirements for

allowable stress design of masonry, in which the calculated stresses resulting from nominal loads
must not exceed permissible masonry and steel stresses.

Chapter 9. Strength Design of Masonry—This chapter provides minimum requirements for

strength design of masonry, in which internal forces resulting from the application of factored loads
must not exceed design strength (nominal member strength reduced by a strength-reduction factor ϕ).

Chapter 10. Prestressed Masonry—Prestressed Masonry requirements are omitted from the
current version of the code as they may not be of practical use in Saudi Arabia.

Chapter 11. Strength Design of Autoclaved Aerated Concrete (AAC) Masonry— This chapter
provides minimum requirements for the design of AAC masonry. According to this chapter, AAC
masonry members shall be proportioned so that the design strength equals or exceeds the required
strength. Design strength is the nominal strength multiplied by the strength-reduction factor, ϕ and
required strength shall be determined in accordance with the strength design load combinations of
SBC 301.

Chapter 12. Veneer—A masonry wythe that provides the exterior finish of a wall system and
transfers out-of-plane load directly to a backing, but is not considered to add strength or stiffness to
the wall system, is called Veneer. There are two common types of masonry veneer: (1) anchored
masonry veneer, and (2) adhered masonry veneer. This chapter provides requirements for design and
detailing of both types of masonry veneer.

Chapter 13. Glass Unit Masonry—Glass unit masonry is used as a non-load-bearing element in
interior and exterior walls, partitions, window openings, and as an architectural feature. This chapter
provides requirements for the empirical design of glass unit masonry as non-load-bearing elements in
exterior or interior walls.

Chapter 14. Masonry Partition Walls—This chapter provides requirements for the design of
masonry partition walls. These design requirements are prescriptive in nature and based on the
condition that vertical loads are reasonably centered on the walls and lateral loads are limited.
Members not participating in the lateral-force-resisting system of a building may be designed by the
prescriptive

SBC 305-CR- v
SUMMARY OF

provisions of this chapter even though the lateral-force-resisting system is designed under another
chapter.

Appendix A. Empirical Design of Masonry—This appendix provides requirements for the

empirical design of masonry.

Appendix B. Design of Masonry Infill—Appendix B provides minimum requirements for the

structural design of concrete masonry, clay masonry, and AAC masonry infills, either non-
participating or participating.

Appendix C. Limit Design Method—This appendix provides alternative design provisions, called
limit state design provisions, for special reinforced masonry shear walls subjected to in-plane seismic
loading. The limit design is considered to be particularly useful for perforated wall configurations for
which a representative yield mechanism can be determined.

Appendix D. Masonry Fireplaces—This appendix provides the provisions for the design and
construction of masonry fireplaces, consisting of concrete or masonry (referred to as “masonry
fireplaces”).

Appendix E. Masonry Heaters— Masonry heaters are appliances designed to absorb and store heat
from a relatively small fire and to radiate that heat into the building interior. They are thermally more
efficient than traditional fireplaces because of their design. Interior passageways through the heater
allow hot exhaust gases from the fire to transfer heat into the masonry, which then radiates into the
building. Masonry heaters shall be designed and installed in accordance with this appendix.

Appendix F. Masonry Chimneys—The construction of masonry chimneys consisting of solid

masonry units, hollow masonry units grouted solid, stone or concrete shall be in

SBC 305-CR- v
 TABLE OF

TABLE OF CONTENTS

PREFACE TO SBC 305-18...............................................................................................................................................III

SUMMARY OF CHAPTERS...............................................................................................................................................V
TABLE OF CONTENTS...................................................................................................................................................VIII
PART 1 —GENERAL..........................................................................................................................................................1
CHAPTER 1 —GENERAL REQUIREMENTS................................................................................................................2
1.1 —SCOPE.................................................................................................................................................................................................................2
1.2 —CONTRACT DOCUMENTS AND CALCULATIONS...........................................................................................................2
1.3 —APPROVAL OF SPECIAL SYSTEMS OF DESIGN OR CONSTRUCTION.............................................................................2
1.4 —STANDARDS CITED IN THIS CODE.............................................................................................................................2
CHAPTER 2 —NOTATION AND DEFINITIONS............................................................................................................4
2.1 —NOTATION.................................................................................................................................................................4
2.2 —DEFINITIONS..............................................................................................................................................................6
CHAPTER 3 —QUALITY AND CONSTRUCTION......................................................................................................11
3.1 —QUALITY ASSURANCE PROGRAM.............................................................................................................................11
3.2 —CONSTRUCTION CONSIDERATIONS............................................................................................................................11
PART 2 —DESIGN REQUIREMENT.............................................................................................................................17
CHAPTER 4 —GENERAL ANALYSIS AND DESIGN CONSIDERATIONS...........................................................18
4.1 —LOADING.................................................................................................................................................................18
4.2 —MATERIAL PROPERTIES...........................................................................................................................................18
4.3 —SECTION PROPERTIES...............................................................................................................................................19
4.4 —CONNECTION TO STRUCTURAL FRAMES..................................................................................................................19
4.5 —MASONRY NOT LAID IN RUNNING BOND.................................................................................................................19
CHAPTER 5 —STRUCTURAL ELEMENTS.................................................................................................................21
5.1 —MASONRY ASSEMBLIES............................................................................................................................................21
5.2 —BEAMS..............................................................................................................................................................................................................22
5.3 —COLUMNS................................................................................................................................................................24
5.4 —PILASTERS...............................................................................................................................................................24
5.5 —CORBELS.................................................................................................................................................................24
CHAPTER 6 —REINFORCEMENT, METAL ACCESSORIES, AND ANCHOR BOLTS......................................26
6.1 —DETAILS OF REINFORCEMENT AND METAL ACCESSORIES.......................................................................................26
6.2 —ANCHOR BOLTS........................................................................................................................................................27
CHAPTER 7 —SEISMIC DESIGN REQUIREMENTS.................................................................................................30
7.1 —SCOPE...............................................................................................................................................................................................................30
7.2 —GENERAL ANALYSIS................................................................................................................................................30
7.3 —ELEMENT CLASSIFICATION......................................................................................................................................30
7.4 —SEISMIC DESIGN CATEGORY REQUIREMENTS.........................................................................................................32
PART 3 —ENGINEERED DESIGN METHOD..............................................................................................................35
CHAPTER 8 —ALLOWABLE STRESS DESIGN OF MASONRY............................................................................36
8.1 —GENERAL.................................................................................................................................................................36
8.2 —UNREINFORCED MASONRY.......................................................................................................................................39
8.3 —REINFORCED MASONRY...........................................................................................................................................40
CHAPTER 9 —STRENGTH DESIGN OF MASONRY................................................................................................44
9.1 —GENERAL.................................................................................................................................................................44
9.2 —UNREINFORCED (PLAIN) MASONRY..........................................................................................................................46
9.3 —REINFORCED MASONRY...........................................................................................................................................47

SBC 305-CR- vi
 TABLE OF

CHAPTER 10 —PRESTRESSED MASONRY.............................................................................................................56

CHAPTER 11 —STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC) MASONRY.........57
11.1 —GENERAL......................................................................................................................................................................................................57
11.2 —UNREINFORCED (PLAIN) AAC MASONRY...............................................................................................................58
11.3 —REINFORCED AAC MASONRY................................................................................................................................59
PART 4 —PRESCRIPTIVE DESIGN METHOD...........................................................................................................66
CHAPTER 12 —VENEER................................................................................................................................................67
12.1 —GENERAL......................................................................................................................................................................................................67
12.2 —ANCHORED VENEER...............................................................................................................................................67
12.3 —ADHERED VENEER.................................................................................................................................................70
CHAPTER 13 —GLASS UNIT MASONRY...................................................................................................................71
13.1 —GENERAL......................................................................................................................................................................................................71
13.2 —PANEL SIZE............................................................................................................................................................71
13.3 —SUPPORT........................................................................................................................................................................................................71
13.4 —EXPANSION JOINTS................................................................................................................................................72
13.5 —BASE SURFACE TREATMENT..................................................................................................................................72
13.6 —MORTAR........................................................................................................................................................................................................72
13.7 —REINFORCEMENT...................................................................................................................................................72
CHAPTER 14 —MASONRY PARTITION WALLS......................................................................................................74
14.1 —GENERAL......................................................................................................................................................................................................74
14.2 —PRESCRIPTIVE DESIGN OF PARTITION WALLS........................................................................................................74
14.3 —LATERAL SUPPORT.................................................................................................................................................74
14.4 —ANCHORAGE..........................................................................................................................................................75
14.5 —MISCELLANEOUS REQUIREMENTS...........................................................................................................................75
PART 5 —APPENDICES.................................................................................................................................................77
APPENDIX A —EMPIRICAL DESIGN OF MASONRY..............................................................................................78
A.1 —GENERAL................................................................................................................................................................78
A.2 —HEIGHT...........................................................................................................................................................................................................78
A.3 —LATERAL STABILITY...............................................................................................................................................78
A.4 —COMPRESSIVE STRESS REQUIREMENTS...................................................................................................................78
A.5 —LATERAL SUPPORT.................................................................................................................................................79
A.6 —THICKNESS OF MASONRY.......................................................................................................................................79
A.7 —BOND...............................................................................................................................................................................................................80
A.8 —ANCHORAGE...........................................................................................................................................................81
A.9 —MISCELLANEOUS REQUIREMENTS............................................................................................................................82
APPENDIX B —DESIGN OF MASONRY INFILL........................................................................................................88
B.1 —GENERAL................................................................................................................................................................88
B.2 —NON-PARTICIPATING INFILLS...................................................................................................................................88
B.3 —PARTICIPATING INFILLS...........................................................................................................................................88
APPENDIX C —LIMIT DESIGN METHOD....................................................................................................................91
C.0 —GENERAL................................................................................................................................................................91
C.1 —YIELD MECHANISM..................................................................................................................................................91
C.2 —MECHANISM STRENGTH..........................................................................................................................................91
C.3 —MECHANISM DEFORMATION...................................................................................................................................91
APPENDIX D —MASONRY FIREPLACES..................................................................................................................92
D.1 —GENERAL................................................................................................................................................................92
D.2 —FIREPLACE DRAWINGS............................................................................................................................................92
D.3 —FOOTINGS AND FOUNDATIONS.................................................................................................................................92
D.4 —SEISMIC REINFORCEMENT.......................................................................................................................................92
D.5 —SEISMIC ANCHORAGE.............................................................................................................................................92
D.6 —FIREBOX WALLS.....................................................................................................................................................92

SBC 305-CR- ix
 TABLE OF

D.7 —FIREBOX DIMENSIONS.............................................................................................................................................93

D.8 —LINTEL AND THROAT..............................................................................................................................................93
D.9 —SMOKE CHAMBER WALLS.......................................................................................................................................93
D.10 —HEARTH AND HEARTH EXTENSION........................................................................................................................93
D.11 —HEARTH EXTENSION DIMENSIONS.........................................................................................................................93
D.12 —FIREPLACE CLEARANCE........................................................................................................................................93
D.13 —FIREPLACE FIRE BLOCKING..................................................................................................................................94
D.14 —EXTERIOR AIR.......................................................................................................................................................94
APPENDIX E —MASONRY HEATERS.........................................................................................................................96
E.1 —DEFINITION.............................................................................................................................................................96
E.2 —INSTALLATION........................................................................................................................................................96
E.3 —FOOTINGS AND FOUNDATION..................................................................................................................................96
E.4 —SEISMIC REINFORCING............................................................................................................................................96
E.5 —MASONRY HEATER CLEARANCE..............................................................................................................................96
APPENDIX F —MASONRY CHIMNEYS.......................................................................................................................97
F.1 —GENERAL................................................................................................................................................................97
F.2 —FOOTINGS AND FOUNDATIONS................................................................................................................................97
F.3 —SEISMIC REINFORCEMENT.......................................................................................................................................97
F.4 —SEISMIC ANCHORAGE..............................................................................................................................................97
F.5 —CORBELING.............................................................................................................................................................97
F.6 —CHANGES IN DIMENSION.........................................................................................................................................97
F.7 —OFFSETS..................................................................................................................................................................97
F.8 —ADDITIONAL LOAD..................................................................................................................................................98
F.9 —TERMINATION.........................................................................................................................................................98
F.10 —WALL THICKNESS..................................................................................................................................................98
F.11 —FLUE LINING (MATERIAL).....................................................................................................................................98
F.12 —CLAY FLUE LINING (INSTALLATION).....................................................................................................................99
F.13 —ADDITIONAL REQUIREMENTS................................................................................................................................99
F.14 —MULTIPLE FLUES...................................................................................................................................................99
F.15 —FLUE AREA (APPLIANCE)......................................................................................................................................100
F.16 —FLUE AREA (MASONRY FIREPLACE)....................................................................................................................100
F.17 —INLET...........................................................................................................................................................................................................100
F.18 —MASONRY CHIMNEY CLEANOUT OPENINGS.........................................................................................................100
F.19 —CHIMNEY CLEARANCES.......................................................................................................................................100
F.20 —CHIMNEY FIRE BLOCKING...................................................................................................................................100

SBC 305-CR- x
PART 1—

PART 1—GENERAL

SBC 305-CR- 1
 CHAPTER 1—GENERAL

CHAPTER 1—GENERAL REQUIREMENTS

1.1 —Scope (i) Size and permitted location of conduits,

1.1.1 Minimum requirements pipes, and sleeves.

The Saudi Building Code for Masonry Structures 1.2.2 Each portion of the structure shall be
referred to as SBC 305 provides minimum designed based on the specified compressive
requirements for the structural design and strength of masonry for that part of the structure,
construction of masonry elements consisting of except for portions designed in accordance with
masonry units bedded in mortar. Part 4 or Appendix A.
1.1.2 Governing building code 1.2.3 The contract documents shall be consistent
with design assumptions.
SBC 305 shall govern in matters pertaining to
structural design and construction of masonry 1.2.4 Contract documents shall specify the
elements. In areas without a legally adopted minimum level of quality assurance as defined in
building code, this Code defines the minimum Section 3.1, or shall include an itemized quality
acceptable standards of design and construction assurance program that equals or exceeds the
practice. requirements of Section 3.1.
1.1.3 Unit information 1.3 —Approval of special systems of
design or construction
The equations in this document are for use with
the specified mm-newton units Sponsors of any system of design or construction
within the scope of this Code, the adequacy of
1.2 —Contract documents and which has been shown by successful use or by
calculations analysis or test, but that does not conform to or is
1.2.1 Show all Code-required drawing items on not addressed by this Code, shall have the right to
the project drawings, including: present the data on which their design is based to a
board of examiners appointed by the building
(a) Name and date of issue of Code and official. The board shall be composed of licensed
supplement to which the design conforms. design professionals and shall have authority to
(b) Loads used for the design of masonry investigate the submitted data, require tests, and
structures. formulate rules governing design and construction
(c) Specified compressive strength of of such systems to meet the intent of this Code.
masonry at stated ages or stages of The rules, when approved and promulgated by the
construction for which masonry is building official, shall be of the same force and
designed, for each part of the structure, effect as the provisions of this Code.
except for masonry designed in
accordance with Part 4 or Appendix A. 1.4 —Standards cited in this Code
(d) Size and location of structural elements. Standards of the American Concrete Institute, the
(e) Details of anchorage of masonry to American Society of Civil Engineers, ASTM
structural members, frames, and other International, the American Welding Society, and
construction, including the type, size, and The Masonry Society cited in this Code are listed
location of connectors. below with their serial designations, including year
(f) Details of reinforcement, including the of adoption or revision, and are declared to be part
size, grade, type, lap splice length, and of this Code as if fully set forth in this document.
location of reinforcement.
(g) Reinforcing bars to be welded and welding TMS 602-13/ACI 530.1-13/ASCE 6-13 —
requirements. Specification for Masonry Structures
(h) Provision for dimensional changes SBC-301 — Minimum Design Loads for
resulting from elastic deformation, creep, Buildings and Other Structures
shrinkage, temperature, and moisture.

SBC 305-CR- 2
 CHAPTER 1—GENERAL

ASTM A416/A416M-12 — Standard ASTM C482-02 (2009) — Standard Test Method

Specification for Steel Strand, Uncoated Seven- for Bond Strength of Ceramic Tile to Portland
Wire for Prestressed Concrete Cement Paste
ASTM A421/A421M-10 — Standard ASTM C1006-07 — Standard Test Method for
Specification for Uncoated Stress-Relieved Steel Splitting Tensile Strength of Masonry Units
Wire for Prestressed Concrete
ASTM C1611/C1611M-09bel — Standard Test
ASTM A706/A706M-09b — Standard Method for Slump Flow of Self-Consolidating
Specification for Low-Alloy Steel Deformed and Concrete
Plain Bars for Concrete Reinforcement
ASTM C1693-11 — Standard Specification for
ASTM C34-12 — Standard Specification for Autoclaved Aerated Concrete (AAC)
Structural Clay Load-Bearing Wall Tile
ASTM E111-04 (2010) — Standard Test Method
ASTM C140-12a — Standard Test Methods for for Young's Modulus, Tangent Modulus, and
Sampling and Testing Concrete Masonry Units Chord Modulus
and Related Units
ASTM E488-96 (2003) Standard Test Methods for
ASTM C426-10 — Standard Test Method for Strength of Anchors in Concrete and Masonry
Linear Drying Shrinkage of Concrete Masonry Elements
Units
AWS D 1.4/D1.4M: 2011 — Structural Welding
ASTM C476-10 — Standard Specification for Code — Reinforcing Steel
Grout for Masonry

SBC 305-CR- 3
 CHAPTER 2—NOTATION AND

CHAPTER 2—NOTATION AND DEFINITIONS

2.1 —Notation 𝐵𝑣𝑛𝑏 nominal shear strength of an anchor bolt

𝐴𝑏 when governed by masonry breakout, N
cross-sectional area2 of an anchor bolt, mm2 𝐵𝑣𝑛𝑐 nominal shear strength of an anchor bolt
𝐴𝑏𝑟 bearing area, mm when governed by masonry crushing, N
𝐴𝑔 gross cross-sectional area of a member, 𝐵𝑣𝑛𝑝𝑟𝑦 nominal shear strength of an anchor bolt
mm2 when governed by anchor pryout, N
𝐴𝑛 net cross-sectional area of a member, mm2 𝐵𝑣𝑛𝑠 nominal shear strength of an anchor bolt
𝐴𝑛𝑣 net shear area, mm2 when governed by steel yielding, N
𝐴𝑝𝑡 projected tension area on masonry surface 𝐵𝑣𝑝𝑟𝑦 allowable shear load on an anchor bolt
of a right circular cone, mm2 when governed by anchor pryout, N
𝐴𝑝𝑣 projected shear area on masonry surface of 𝐵𝑣𝑠 allowable shear load on an anchor bolt
one-half of a right circular cone, mm2 when governed by steel yielding, N
𝐴𝑠 area of nonprestressed longitudinal tension 𝑏 width of section, mm
reinforcement, mm2 𝑏𝑎 total applied design axial force on an
𝐴𝑠𝑐 area of reinforcement placed within the anchor bolt, N
lap, near each end of the lapped reinforcing 𝑏𝑎𝑓 factored axial force in an anchor bolt, N
bars
and transverse to them, mm2 𝑏𝑣 total applied design shear force on an
𝐴𝑠𝑡 total area of laterally tied longitudinal anchor bolt, N
reinforcing steel, mm2 𝑏𝑣𝑓 factored shear force in an anchor bolt, N
𝐴𝑣 cross-sectional area of shear reinforcement, 𝑏𝑤 width of wall beam, mm
mm2 𝐶𝑑 deflection amplification factor
𝐴 loaded area, mm2
1 𝑐 distance from the fiber of maximum
𝐴2 supporting bearing area, mm2 compressive strain to the neutral axis, mm
𝑎 depth of an equivalent compression stress 𝐷 dead load or related internal moments and
block at nominal strength, mm forces
𝐵𝑎 allowable axial load on an anchor bolt, N 𝑑 distance from extreme compression fiber
𝐵𝑎𝑏 allowable axial tensile load on an anchor to centroid of tension reinforcement, mm
bolt when governed by masonry breakout, 𝑑𝑏 nominal diameter of reinforcement or
N anchor bolt, mm
𝐵𝑎𝑛 nominal axial strength of an anchor bolt, N 𝑑𝑣 actual depth of a member in direction of
𝐵𝑎𝑛𝑏 nominal axial tensile strength of an anchor shear considered, mm
bolt when governed by masonry breakout, 𝐸 load effects of earthquake or related
N internal moments and forces
𝐵𝑎𝑛𝑝 nominal axial tensile strength of an anchor 𝐸𝐴𝐴𝐶 modulus of elasticity of AAC masonry in
bolt when governed by anchor pullout, N compression, MPa
𝐵𝑎𝑛𝑠 nominal axial tensile strength of an anchor 𝐸𝑏𝑏 modulus of elasticity of bounding beams,
bolt when governed by steel yielding, N MPa
𝐵𝑎𝑝 allowable axial tensile load on an anchor 𝐸𝑏𝑐 modulus of elasticity of bounding
bolt when governed by anchor pullout, N columns, MPa
𝐵𝑎𝑠 allowable axial tensile load on an anchor 𝐸𝑚 modulus of elasticity of masonry in
bolt when governed by steel yielding, N compression, MPa
𝐵𝑣 allowable shear load on an anchor bolt, N 𝐸𝑠 modulus of elasticity of steel, MPa
𝐵𝑣𝑏 allowable shear load on an anchor bolt 𝐸𝑣 modulus of rigidity (shear modulus) of
when governed by masonry breakout, N masonry, MPa
𝐵𝑣𝑐 allowable shear load on an anchor bolt 𝑒 eccentricity of axial load, mm
when governed by masonry crushing, N 𝑒𝑏 projected leg extension of bent-bar anchor,
𝐵𝑣𝑛 nominal shear strength of an anchor bolt, N measured from inside edge of anchor at

SBC 305-CR- 4
 CHAPTER 2—NOTATION AND

bend to farthest point of anchor in the 𝑗 ratio of distance between centroid of

plane of the hook, mm flexural compressive forces and centroid
𝑒𝑢 eccentricity of 𝑃𝑢𝑓, mm of tensile forces to depth, 𝑑
𝐹𝑎 allowable compressive stress available to 𝐾 dimension used to calculate reinforcement
resist axial load only, MPa development, mm
𝐹𝑏 allowable compressive stress available to 𝐾𝐴𝐴𝐶 dimension used to calculate reinforcement
resist flexure only, MPa development for AAC masonry, mm
𝐹𝑠 allowable tensile or compressive stress in 𝑘𝑐 coefficient of creep of masonry, per MPa
reinforcement, MPa
𝑘𝑒 coefficient of irreversible moisture
𝐹𝑣 allowable shear stress, MPa expansion of clay masonry
𝐹𝑣𝑚 allowable shear stress resisted by the 𝑘𝑚 coefficient of shrinkage of concrete
masonry, MPa masonry
𝐹𝑣𝑠 allowable shear stress resisted by the shear 𝑘𝑡 coefficient of thermal expansion of
reinforcement, MPa masonry per degree Celsius
𝑓𝑎 calculated compressive stress in masonry 𝐿 live load or related internal moments and
due to axial load only, MPa forces
𝑓𝑏 calculated compressive stress in masonry 𝑙 clear span between supports, mm
due to flexure only, MPa
𝑙𝑏 effective embedment length of headed or
𝑓′ specified compressive strength of AAC bent anchor bolts, mm
𝐴
masonry, MPa 𝑙𝑏𝑒 anchor bolt edge distance, mm
𝑓′ specified compressive strength of grout, 𝑙𝑑 development length or lap length of
�
MPa straight reinforcement, mm
𝑓′ specified compressive strength of clay 𝑙𝑒 equivalent embedment length provided by
�
masonry or concrete masonry, MPa standard hooks measured from the start of
𝑓𝑟 modulus of rupture, MPa the hook (point of tangency), mm
𝑓𝑟𝐴𝐴𝐶 modulus of rupture of AAC, MPa 𝑙𝑒𝑓𝑓 effective span length for a deep beam, mm
𝑓𝑠 calculated tensile or compressive stress in 𝑙𝑖𝑛𝑓 plan length of infill, mm
reinforcement, MPa
𝑙𝑤 length of entire wall or of the segment of
𝑓𝑠𝑒 effective stress in prestressing tendon after wall considered in direction of shear force,
all prestress losses have occurred, MPa mm
𝑓𝑡𝐴𝐴𝐶 splitting tensile strength of AAC as 𝑀 maximum moment at the section under
determined in accordance with ASTM consideration, N-mm
C1006, MPa
𝑀𝑎 maximum moment in member due to the
𝑓𝑣 calculated shear stress in masonry, MPa
applied unfactored loading for which
𝑓𝑦 specified yield strength of steel for deflection is calculated, N-mm
reinforcement and anchors, MPa 𝑀𝑐𝑟 nominal cracking moment strength, N-mm
ℎ effective height of column, wall, or 𝑀𝑛 nominal moment strength, N-mm
pilaster, mm 𝑀𝑠𝑒𝑟 service moment at midheight of a member,
ℎ𝑖𝑛𝑓 vertical dimension of infill, mm including P-delta effects, N-mm
ℎ𝑤 height of entire wall or of the segment of 𝑀𝑢 factored moment, magnified by second-
wall considered, mm order effects where required by the code,
𝐼𝑏𝑏 moment of inertia of bounding beam for N-mm
bending in the plane of the infill, mm4 𝑀𝑢, factored moment from first-order analysis,
0
𝐼𝑏𝑐 moment of inertia of bounding column for N-mm
bending in the plane of the infill, mm4 𝑛 modular ratio,𝐸𝑠/𝐸𝑚
𝐼𝑐𝑟 moment of inertia of cracked cross- 𝑁𝑢 factored compressive force acting normal
sectional area of a member, mm4 to shear surface that is associated with the
𝐼𝑒𝑓𝑓 effective moment of inertia, mm4 𝑉𝑢 loading combination case under
𝐼𝑔 moment of inertia of gross cross-sectional consideration, N
area of a member, mm4 𝑁𝑣 compressive force acting normal to shear
𝐼 moment of inertia of net cross-sectional surface, N
𝑛
𝑃 Axial load, N
area of a member, mm4
𝑃𝑎 allowable axial compressive force in a
reinforced member, N

SBC 305-CR- 5
 CHAPTER 2—NOTATION AND

𝑃𝑒 Euler buckling load, N 𝑊𝑇 dimension of the tributary length of wall,

𝑃𝑛 nominal axial strength, N defined in Sections 14.3.2 and A.5.1 and
𝑃𝑢 factored axial load, N shown in
𝑃𝑢𝑓 factored load from tributary floor or roof Figure 14.1 and Figure A.2.
areas, N 𝑤 𝑖𝑛𝑓 width of equivalent strut, mm
𝑃𝑢𝑤 factored weight of wall area tributary to 𝑤𝑠𝑡𝑟𝑢𝑡 horizontal projection of the width of the
wall section under consideration, N diagonal strut, mm
𝑄 first moment about the neutral axis of an 𝑤𝑢 out-of-plane factored uniformly
area between the extreme fiber and the distributed load, N/mm
plane at which the shear stress is being 𝑧 internal lever arm between compressive
calculated, mm3 and tensile forces in a deep beam, mm
𝑄𝐸 the effect of horizontal seismic 𝛼𝑎𝑟𝑐ℎ horizontal arching parameter for infill,
(earthquake induced) forces
N0.25
𝑞𝑛 𝑖𝑛𝑓 nominal out-of-plane flexural capacity of
𝛽𝑎𝑟𝑐ℎ vertical arching parameter for infill, N0.25
infill per unit area, Pa
𝛽𝑏 ratio of area of reinforcement cut off to
𝑞𝑧 velocity pressure determined in total area of tension reinforcement at a
accordance with SBC 301, kPa section
𝑅 response modification coefficient 𝛾 reinforcement size factor
𝑟 radius of gyration, mm 𝛾𝑔 grouted shear wall factor
𝑆 snow load or related internal moments and ∆ calculated story drift, mm
forces
∆𝑎 allowable story drift, mm
𝑆𝑛 section modulus of the net cross-sectional 𝛿 moment magnification factor
area of a member, mm3
𝛿𝑛𝑒 displacements calculated using code-
𝑠 spacing of reinforcement, mm prescribed seismic forces and assuming
𝑠𝑙 total linear drying shrinkage of concrete elastic behavior, mm
masonry units determined in accordance 𝛿𝑠 horizontal deflection at midheight under
with ASTM C426 allowable stress design load combinations,
𝑡 nominal thickness of member, mm mm
𝑡𝑖𝑛𝑓 specified thickness of infill, mm 𝛿𝑢 Deflection due to factored loads, mm
𝑡𝑛𝑒𝑡 𝑖𝑛𝑓 net thickness of infill, mm 𝜀𝑐𝑠 drying shrinkage of AAC
𝑡𝑠𝑝 specified thickness of member, mm 𝜀𝑚𝑢 maximum usable compressive strain of
𝑣 shear stress, MPa masonry
𝑉 shear force, N 𝜉 lap splice confinement reinforcement factor
𝑉𝑙𝑖𝑚 limiting base-shear strength, N 𝜃𝑠𝑡𝑟𝑢𝑡 angle of infill diagonal with respect to the
𝑉𝑛𝐴𝐴𝐶 nominal shear strength provided by AAC horizontal, degrees
masonry, N 𝜆𝑠𝑡𝑟𝑢𝑡 characteristic stiffness parameter for infill,
𝑉𝑛 nominal shear strength, N mm−1
𝑉𝑛 𝑖𝑛𝑓 nominal horizontal in-plane shear strength 𝜇𝐴𝐴𝐶 coefficient of friction of AAC
of infill, N 𝜌 reinforcement ratio
𝑉𝑛𝑚 nominal shear strength provided by 𝜌𝑚𝑎𝑥 maximum flexural tension reinforcement
masonry, N ratio
𝑉𝑛𝑠 nominal shear strength provided by shear 𝜙 strength-reduction factor
reinforcement, N 𝜓 magnification factor for second-order
𝑉𝑢 factored shear force, N effects
𝑉𝑢𝑏 base-shear demand, N
2.2 —Definitions
𝑊 wind load or related internal moments and
forces Anchor — Metal rod, wire, or strap that secures
𝑊𝑠 dimension of the structural wall strip masonry to its structural support.
defined in Sections 14.3.2 and A.5.1 and Anchor pullout — Anchor failure defined by the
shown in anchor sliding out of the material in which
Figure 14.1 and Figure A.2. it is embedded without breaking out a
substantial portion of the surrounding
material.

SBC 305-CR- 6
 CHAPTER 2—NOTATION AND

Area, gross cross-sectional — The area delineated components act together as a single
by the out-to-out dimensions of masonry member.
in the plane under consideration. Composite masonry — Multiwythe masonry
Area, net cross-sectional — The area of masonry members with wythes bonded to produce
units, grout, and mortar crossed by the composite action.
plane under consideration based on out-to- Compressive strength of masonry — Maximum
out dimensions. compressive force resisted per unit of net
Area, net shear — The net area of the web of a cross-sectional area of masonry,
shear element. determined by testing masonry prisms or a
Autoclaved aerated concrete — Low-density function of individual masonry units,
cementitious product of calcium silicate mortar, and grout, in accordance with the
hydrates, whose material specifications are provisions of TMS 602/ACI 530.1/ ASCE
defined in ASTM C1693. 6.
Autoclaved aerated concrete (AAC) — Masonry - Connector — A mechanical device for securing
Autoclaved Aerated concrete units two or more pieces, parts, or members together,
manufactured without reinforcement, set including anchors, wall ties, and fasteners.
on a mortar leveling bed, bonded with Contract documents — Documents establishing
thin- bed mortar, placed with or without the required work, and including in particular,
grout, and placed with or without the project drawings and project
reinforcement. specifications.
Backing — Wall or surface to which veneer is Corbel — A projection of successive courses from
attached. the face of masonry.
Bed joint — The horizontal layer of mortar on Cover, grout — thickness of grout surrounding the
which a masonry unit is laid. outer surface of embedded reinforcement,
Bond beam — a horizontal, sloped, or stepped anchor, or tie.
element that is fully grouted, has Cover, masonry — thickness of masonry units,
longitudinal bar reinforcement, and is mortar, and grout surrounding the outer
constructed within a masonry wall. surface of embedded reinforcement,
Bounding frame — The columns and upper and anchor, or tie.
lower beams or slabs that surround Cover, mortar — thickness of mortar surrounding
masonry infill and provide structural the outer surface of embedded
support. reinforcement, anchor, or tie.
Building official — The officer or other designated Deep beam — A beam that has an effective span-
authority charged with the administration to depth ratio, 𝑙𝑒𝑓𝑓/𝑑𝑣, less than 3 for a
and enforcement of this Code, or the continuous span and less than 2 for a
building official's duly authorized simple span.
representative. Depth — The dimension of a member measured in
Cavity wall — A masonry wall consisting of two the plane of a cross section perpendicular
or more wythes, at least two of which are to the neutral axis.
separated by a continuous air space; air Design story drift — The difference of deflections
space(s) between wythes may contain at the top and bottom of the story under
insulation; and separated wythes must be consideration, taking into account the
connected by wall ties. possibility of inelastic deformations as
Collar joint — Vertical longitudinal space between defined in SBC 301. In the equivalent
wythes of masonry or between masonry lateral force method, the story drift is
wythe and backup construction, which is calculated by multiplying the deflections
permitted to be filled with mortar or grout. determined from an elastic analysis by the
Column — A structural member, not built appropriate deflection amplification factor,
integrally into a wall, designed primarily
𝐶𝑑 from SBC 301.
to resist compressive loads parallel to its Design strength — The nominal strength of an
longitudinal axis and subject to element multiplied by the appropriate
dimensional limitations. strength-reduction factor.
Composite action — Transfer of stress between Diaphragm — A roof or floor system designed to
components of a member designed so that transmit lateral forces to shear walls or
in resisting loads, the combined other lateral-force resisting elements.

SBC 305-CR- 7
 CHAPTER 2—NOTATION AND

Dimension, nominal — The specified dimension in the area where the work has been or is
plus an allowance for the joints with being performed, and observation upon
which the units are to be laid. Nominal completion of the work.
dimensions are usually stated in whole Licensed design professional — An individual
numbers nearest to the specified who is licensed to practice design as
dimensions. defined by the statutory requirements of
Dimensions, specified — Dimensions specified for the professional licensing laws of the state
the manufacture or construction of a unit, or jurisdiction in which the project is to be
joint, or element. constructed and who is in responsible
Effective height — Clear height of a member charge of the design; in other documents,
between lines of support or points of also referred to as registered design
support and used for calculating the professional.
slenderness ratio of a member. Effective Load, dead — Dead weight supported by a
height for unbraced members shall be member, as defined by SBC 301.
calculated. Load, live — Live load specified by SBC 301.
Foundation pier — A vertical foundation member, Load, service — Load specified by SBC 301.
not built integrally into a foundation wall, Longitudinal reinforcement — Reinforcement
empirically designed to support gravity placed parallel to the longitudinal axis of
loads and subject to dimensional the member.
limitations. Masonry breakout — Anchor failure defined by
Glass unit masonry — Masonry composed of glass the separation of a volume of masonry,
units bonded by mortar. approximately conical in shape, from the
Grout — (1) A plastic mixture of member.
cementitious materials, aggregates, and Masonry, partially grouted — Construction in
water, with or without admixtures, initially which designated cells or spaces are filled
produced to pouring consistency without with grout, while other cells or spaces are
segregation of the constituents during ungrouted.
placement. Masonry unit, hollow — A masonry unit with net
(2) The hardened equivalent of such mixtures. cross-sectional area of less than 75 percent
Grout, self-consolidating — A highly fluid and of its gross cross-sectional area when
stable grout typically with admixtures, that measured in any plane parallel to the
remains homogeneous when placed and surface containing voids.
does not require puddling or vibration for Masonry unit, solid — A masonry unit with net
consolidation. cross-sectional area of 75 percent or more
Head joint — Vertical mortar joint placed between of its gross cross-sectional area when
masonry units within the wythe at the time measured in every plane parallel to the
the masonry units are laid. surface containing voids.
Header (bonder) — A masonry unit that connects Modulus of elasticity — Ratio of normal stress to
two or more adjacent wythes of masonry. corresponding strain for tensile or
Infill — Masonry constructed within the plane of, compressive stresses below proportional
and bounded by, a structural frame. limit of material.
Infill, net thickness — Minimum total thickness of Modulus of rigidity — Ratio of unit shear stress to
the net cross-sectional area of an infill. unit shear strain for unit shear stress below
Infill, non-participating — Infill designed so that the proportional limit of the material.
in- plane loads are not imparted to it from Nominal strength — The strength of an element or
the bounding frame. cross section calculated in accordance with
Infill, participating — Infill designed to resist in- the requirements and assumptions of the
plane loads imparted to it by the bounding strength design methods of these
frame. provisions before application of strength-
Inspection, continuous — The Inspection Agency's reduction factors.
full-time observation of work by being Partition wall — An interior wall without
present in the area where the work is being structural function.
performed. Pier —A reinforced, vertically spanning portion of
Inspection, periodic — The Inspection Agency's a wall next to an opening, designed using
part-time or intermittent observation of
work during construction by being present

SBC 305-CR- 8
 CHAPTER 2—NOTATION AND

strength design, and subject to Shear wall, ordinary plain (unreinforced) masonry
dimensional limitations. — A masonry shear wall designed to resist
Prism — An assemblage of masonry units and lateral forces while neglecting stresses in
mortar, with or without grout, used as a reinforcement, if present.
test specimen for determining properties Shear wall, ordinary reinforced AAC masonry —
of the masonry. An AAC masonry shear wall designed to
Project drawings — The drawings that, along with resist lateral forces while considering
the project specifications, complete the stresses in reinforcement and satisfying
descriptive information for constructing prescriptive reinforcement and connection
the work required by the contract requirements.
documents. Shear wall, ordinary reinforced masonry — A
Project specifications — The written documents masonry shear wall designed to resist
that specify requirements for a project in lateral forces while considering stresses in
accordance with the service parameters reinforcement and satisfying prescriptive
and other specific criteria established by reinforcement and connection
the owner or the owner's agent. requirements.
Quality assurance — The administrative and Shear wall, special reinforced masonry — A
procedural requirements established by the masonry shear wall designed to resist
contract documents to assure that lateral forces while considering stresses in
constructed masonry is in compliance with reinforcement and to satisfy special
the contract documents. reinforcement and connection
Reinforcement — Nonprestressed steel requirements.
reinforcement. Slump flow — The circular spread of plastic self-
Required strength — The strength needed to resist consolidating grout, which is evaluated in
factored loads. accordance with ASTM C1611/C1611M.
Running bond — The placement of masonry units Special boundary elements — in walls that are
so that head joints in successive courses designed to resist in-plane load, end
are horizontally offset at least one-quarter regions that are strengthened by
the unit length. reinforcement and are detailed to meet
Shear wall — A wall, load-bearing or non-load- specific requirements, and may or may not
bearing, designed to resist lateral forces be thicker than the wall.
acting in the plane of the wall (sometimes Specified compressive strength of AAC masonry,
referred to as a vertical diaphragm). 𝑓′ — Minimum compressive strength,
Shear wall, detailed plain (unreinforced) AAC 𝐴
expressed as force per unit of net cross-
masonry — An AAC masonry shear wall sectional area, required of the AAC
designed to resist lateral forces while masonry used in construction by the
neglecting stresses in reinforcement, contract documents, and upon which the
although provided with minimum project design is based. Whenever the
reinforcement and connections. quantity 𝑓′ is under the radical sign, the
Shear wall, detailed plain (unreinforced) masonry 𝐴
square root of numerical value only is
— A masonry shear wall designed to resist intended and the result has units of MPa.
lateral forces while neglecting stresses in Specified compressive strength of masonry, 𝑓′ —
reinforcement, although provided with Minimum compressive strength, expressed
�
minimum reinforcement and connections. as force per unit of net cross-sectional
Shear wall, intermediate reinforced masonry — A area, required of the masonry used in
masonry shear wall designed to resist construction by the contract documents,
lateral forces while considering stresses in and upon which the project design is
reinforcement and to satisfy specific based. Whenever the quantity 𝑓′ is under
minimum reinforcement and connection �
the radical sign, the square root of
requirements. numerical value only is intended and the
Shear wall, ordinary plain (unreinforced) AAC result has units of MPa.
masonry — An AAC masonry shear wall Stirrup — Reinforcement used to resist shear in a
designed to resist lateral forces while flexural member.
neglecting stresses in reinforcement, if
present.

SBC 305-CR- 9
 CHAPTER 2—NOTATION AND

Stone masonry — Masonry composed of field, through anchors and supported vertically
quarried, or cast stone units bonded by by the foundation or other structural
mortar. elements.
Stone masonry, ashlar — Stone masonry Veneer, masonry — A masonry wythe that
composed of rectangular units having provides the exterior finish of a wall
sawed, dressed, or squared bed surfaces system and transfers out-of-plane load
and bonded by mortar. directly to a backing, but is not considered
Stone masonry, rubble — Stone masonry to add strength or stiffness to the wall
composed of irregular-shaped units bonded by system.
mortar. Strength-reduction factor, 𝜙 — the factor Visual stability index (VSI) — an index, defined
by which the nominal strength is multiplied to in ASTM C1611/C1611M, that
obtain qualitatively indicates the stability of self-
the design strength. consolidating grout
Thin-bed mortar — Mortar for use in construction Wall — A vertical element with a horizontal
of AAC unit masonry whose joints shall length to thickness ratio greater than 3,
not be less than 1.5 mm. used to enclose space.
Tie, lateral — Loop of reinforcing bar or wire Wall, load-bearing — Wall supporting vertical
enclosing longitudinal reinforcement. loads greater than 3000 N/m in addition to
Tie, wall — Metal connector that connects wythes its own weight.
of masonry walls together. Wall, masonry bonded hollow — a multiwythe
Transverse reinforcement — Reinforcement wall built with masonry units arranged to
placed perpendicular to the longitudinal provide an air space between the wythes
axis of the member. and with the wythes bonded together with
Unreinforced (plain) masonry — Masonry in masonry units.
which the tensile resistance of masonry is Width — the dimension of a member measured in
taken into consideration and the resistance the plane of a cross section parallel to the
of reinforcing steel, if present, is neutral axis.
neglected. Wythe — each continuous vertical section of a
Veneer, adhered — Masonry veneer secured to wall, one masonry unit in thickness.
and supported by the backing through adhesion.
Veneer, anchored — Masonry veneer secured to
and supported laterally by the backing

SBC 305-CR- 1
 CHAPTER 3—QUALITY AND

CHAPTER 3—QUALITY AND CONSTRUCTION

3.1 —Quality assurance program 3.1.6.1 Compliance with 𝑓′ — Compressive

�
The quality assurance program shall comply with strength of masonry shall be considered
the requirements of this section, depending on the satisfactory if the compressive strength of each
Risk Category, as defined in SBC 301. The quality masonry wythe and grouted collar joint equals or
assurance program shall itemize the requirements exceeds the value of 𝑓′ .
�
for verifying conformance of material 3.1.6.2 Determination of compressive strength —
composition, quality, storage, handling, Compressive strength of masonry shall be
preparation, and placement with the requirements determined in accordance with the provisions of
of TMS 602/ACI 530.1/ASCE 6. TMS 602/ACI 530.1/ASCE 6.
3.1.1 Level A Quality Assurance 3.2 —Construction considerations
The minimum quality assurance program for 3.2.1 Grouting, minimum spaces
masonry in Risk Category I, II, or III structures
and designed in accordance with Part 4 or The minimum dimensions of spaces provided for
Appendix A shall comply with Table 3.1. the placement of grout shall be in accordance with
Table 3.4. Grout pours with heights exceeding
3.1.2 Level B Quality Assurance those shown in Table 3.4, cavity widths, or cell
3.1.2.1 The minimum quality assurance program sizes smaller than those permitted in Table 3.4 or
for masonry in Risk Category IV structures and grout lift heights exceeding those permitted by
designed in accordance with Chapter 12 or Chapter Article 3.5 D of TMS 602/ACI 530.1/ ASCE 6 are
13 shall comply with Table 3.2. permitted if the results of a grout demonstration
panel show that the grout spaces are filled and
3.1.2.2 The minimum quality assurance program adequately consolidated. In that case, the
for masonry in Risk Category I, II, or III structures procedures used in constructing the grout
and designed in accordance with chapters other demonstration panel shall be the minimum
than those in Part 4 or Appendix A shall comply acceptable standard for grouting, and the quality
with Table 3.2. assurance program shall include inspection during
3.1.3 Level C Quality Assurance construction to verify grout placement.
The minimum quality assurance program for 3.2.2 Embedded conduits, pipes, and sleeves
masonry in Risk Category IV structures and Conduits, pipes, and sleeves of any material to be
designed in accordance with chapters other than embedded in masonry shall be compatible with
those in Part 4 or Appendix A shall comply with masonry and shall comply with the following
Table 3.3. requirements.
3.1.4 Procedures 3.2.2.1 Conduits, pipes, and sleeves shall not be
The quality assurance program shall set forth the considered to be structural replacements for the
procedures for reporting and review. The quality displaced masonry. The masonry design shall
assurance program shall also include procedures consider the structural effects of this displaced
for resolution of noncompliances. masonry.
3.1.5 Qualifications 3.2.2.2 Conduits, pipes, and sleeves in masonry
shall be no closer than 3 diameters on center.
The quality assurance program shall define the Minimum spacing of conduits, pipes or sleeves of
qualifications for testing laboratories and for different diameters shall be determined using the
inspection agencies. larger diameter.
3.1.6 Acceptance relative to strength
requirements

SBC 305-CR- 1
 CHAPTER 3—QUALITY AND

3.2.2.3 Vertical conduits, pipes, or sleeves placed Where concrete abuts structural masonry and the
in masonry columns or pilasters shall not displace joint between the materials is not designed as a
more than 2 percent of the net cross section. separation joint, the concrete shall be roughened so
3.2.2.4 Pipes shall not be embedded in masonry, that the average height of aggregate exposure is 3
unless properly isolated from the masonry, when: mm and shall be bonded to the masonry in
accordance with these requirements as if it were
(a) Containing liquid, gas, or vapors at masonry. Vertical joints not intended to act as
temperature higher than 66°C. separation joints shall be crossed by horizontal
(b) Under pressure in excess of 380 kPa. reinforcement as required by Section 5.1.1.2.
(c) Containing water or other liquids subject
to freezing.
3.2.3 Separation Joints.

SBC 305-CR- 1
 CHAPTER 3—QUALITY AND

TABLES OF CHAPTER 3

Table 3.1: Level A Quality Assurance

MINIMUM VERIFICATION
Table 3.2: Level B Quality Assurance
Prior to construction, verify certificates of compliance used in masonry
construction
MINIMUM TESTS
Verification of Slump flow and Visual Stability Index (VSI) as delivered to
the project site in accordance with Specification Article 1.5 B.1.b.3 for self-
consolidating grout
Verification off 𝑓𝑚′ and 𝑓𝐴𝐴𝐶
′
in accordance with Specification Article 1.4 B prior to construction, except where
specifically exempted by this Code

MINIMUM SPECIAL INSPECTION

Inspection Task Frequency (a) Reference for Criteria
TMS 602/
Continuous Periodic SBC 305 ACI 530.1/
ASCE 6
1. Verify compliance with the approved submittals X Art. 1.5
2. As masonry construction begins, verify
that the following are in compliance:
a. Proportions of site-prepared mortar X Art. 2.1, 2.6 A
b. Construction of mortar joints X Art. 3.3 B
c. Location of reinforcement, connectors, X Art. 3.4, 3.6 A
and anchorages

d. Properties of thin-bed mortar for AAC masonry X(b) X(c) Art. 2.1 C

3. Prior to grouting, verify that the following

are in compliance:
a. Grout space X Art. 3.2 D, 3.2 F
b. Grade, type, and size of reinforcement X Sec. 6.1 Art. 2.4, 3.4
, anchor bolts, and anchorages

c. Placement of reinforcement, connectors, X Sec. 6.1, 6.2.1, Art. 3.2 E, 3.4,

and anchorages 6.2.6, 6.2.7 3.6 A

d. Proportions of site-prepared grout. Art. 2.6 B,

X
2.4 G.1.b

e. Construction of mortar joints X Art. 3.3 B

Continued on next page

SBC 305-CR- 1
CHAPTER 3—QUALITY AND

Table 3.2: Level B Quality Assurance(Continued)

MINIMUM SPECIAL INSPECTION
Inspection Task Frequency (a) Reference for Criteria
Continuous Periodic SBC 305 TMS 602/
ACI 530.1/
ASCE 6
4. Verify during construction:
a. Size and location of structural elements X Art. 3.3 F
b. Type, size, and location of anchors, X Sec. 1.2.1(e),
including other details of anchorage of 6.1.4.3, 6.2.1
masonry to structural members, frames, or
other construction
c. Welding of reinforcement X Sec. 8.1.6.7.2,
9.3.3.4 (c),
11.3.3.4(b)
d. Preparation, construction, and protection of X Art. 1.8 C,
masonry during cold weather (temperature below 1.8 D
4.4°C or hot weather (temperature above 32.2°C)

e. Placement of grout X Art. 3.5, 3.6 C

f. Placement of AAC masonry units and X(b) X(c) Art. 3.3 B.9,
construction of thin-bed mortar joints 3.3 F.1.b
5. Observe preparation of grout specimens, X Art. 1.4 B.2.a.3,
mortar specimens, and/or prisms 1.4 B.2.b.3, 1.4
B.2.c.3, 1.4 B.3,
1.4 B.4

(a) Frequency refers to the frequency of Special Inspection, which may be continuous during the task
listed or periodic during the listed task, as defined in the table.
(b) Required for the first 500 square meters of AAC masonry.
(c) Required after the first 500 square meters of AAC masonry.

SBC 305-CR- 1
CHAPTER 3—QUALITY AND

Table 3.3: Level C Quality Assurance

MINIMUM TESTS
′ ′
Verification of 𝑓𝑚 and 𝑓𝐴𝐶𝐶 in accordance with Specification Article 1.4 B prior to construction and for every 500 sq. m
during construction
Verification of proportions of materials in premixed or preblended mortar, prestressing grout, and grout other than self-
consolidating grout, as delivered to the project site
Verification of Slump flow and Visual Stability Index (VSI) as delivered to the project site in accordance with
Specification Article 1.5 B.1.b.3 for self-consolidating grout
MINIMUM SPECIAL INSPECTION
Inspection Task Frequency (a) Reference for Criteria
Continuous Periodic SBC 305 TMS 602/
ACI 530.1/
ASCE 6
1. Verify compliance with the approved submittals X Art. 1.5
2. Verify that the following are in compliance:
a. Proportions of site-mixed mortar and grout X Art. 2.1, 2.6 A,
2.6 B, 2.6 C,
2.4 G 1.b
b. Grade, type, and size of reinforcement, anchor X Sec. 6.1 Art. 2.4, 3.4
bolts, and
anchorages
c. Placement of masonry units and construction of X Art. 3.3 B
mortar joints
d. Placement of reinforcement, connectors, and X Sec. 6.1,
anchorages 6.2.1, 6.2.6, Art 3.2 E, 3.4,
6.2.7 3.6 A
e. Grout space prior to grouting X Art. 3.2 D, 3.2 F
f. Placement of grout X Art. 3.5, 3.6 C

g. Size and location of structural elements X Art. 3.3 F

h. Type, size, and location of anchors including other X Sec. 1.2.1(e),
details of anchorage of masonry to structural 6.1.4.3, 6.2.1
members, frames, or other construction
i. Welding of reinforcement X Sec. 8.1.6.7.2,
9.3.3.4 (c),
11.3.3.4(b)
j. Preparation, construction, and protection of X Art. 1.8 C,
masonry during cold weather (temperature below 1.8 D
5°C or hot weather (temperature above 32°C)

k. Placement of AAC masonry units and construction X Art. 3.3 B.9,

of thin-bed mortar joints 3.3 F.1.b
l. Properties of thin-bed mortar for AAC masonry X Art. 2.1 C.1
3. Observe preparation of grout specimens, X Art. 1.4 B.2.a.3,
mortar specimens, and/or prisms 1.4 B.2.b.3, 1.4
B.2.c.3, 1.4 B.3,
1.4 B.4
(a) Frequency refers to the frequency of Special Inspection, which may be continuous during the task listed
or periodic during the listed task, as defined in the table.

SBC 305-CR- 1
 CHAPTER 3—QUALITY AND

Table 3.4: Grout space requirements

Grout type1 Maximum grout Minimum clear width Minimum clear grout space dimensions for
pour height, of grout space,2,3 grouting cells of hollow units,3,4, 5
m mm mm × mm
Fine 0.30 20 38×51
Fine 1.60 50 51 × 76
Fine 3.80 60 63 × 76
Fine 7.30 75 76 × 76
Coarse 0.30 38 38 × 76
Coarse 1.60 50 63 × 76
Coarse 3.80 60 76 × 76
Coarse 7.30 75 76 × 102
1
Fine and coarse grouts are defined in ASTM C476.
2
For grouting between masonry wythes.
3
Minimum clear width of grout space and minimum clear grout space dimension are the net dimension of the space
determined by subtracting masonry protrusions and the diameters of horizontal bars from the as-designed cross-section
of the grout space. Grout type and maximum grout pour height shall be specified based on the minimum clear space.
4
Area of vertical reinforcement shall not exceed 6 percent of the area of the grout space.
5
Minimum grout space dimension for AAC masonry units shall be 76 mm × 76 mm or a 76 mm diameter cell.

SBC 305-CR- 1
PART 2—DESIGN

PART 2—DESIGN REQUIREMENT

SBC 305-CR- 1
 CHAPTER 4—GENERAL ANALYSIS AND DESIGN

CHAPTER 4—GENERAL ANALYSIS AND DESIGN

CONSIDERATIONS

4.1.6.1 Flanges of intersecting walls designed in

accordance with Section 5.1.1.2 shall be included
4.1 —Loading in stiffness determination.
4.1.1 General 4.1.6.2 Distribution of load shall be consistent
Masonry shall be designed to resist applicable with the forces resisted by foundations.
loads. A continuous load path or paths, with 4.1.6.3 Distribution of load shall include the effect
adequate strength and stiffness, shall be provided of horizontal torsion of the structure due to
to transfer forces from the point of application to eccentricity of wind or seismic loads resulting
the final point of resistance. from the non-uniform distribution of mass.
4.1.2 Load provisions 4.2 —Material properties
Design loads shall be in accordance with the SBC 4.2.1 General
301, with such live load reductions as are
permitted in SBC 301, except as noted in this Unless otherwise determined by test, the following
Code. moduli and coefficients shall be used in
determining the effects of elasticity, temperature,
4.1.3 Lateral load resistance moisture expansion, shrinkage, and creep.
Buildings shall be provided with a structural 4.2.2 Elastic moduli
system designed to resist wind and earthquake
loads and to accommodate the effect of the 4.2.2.1 Steel reinforcement — Modulus of
resulting deformations. elasticity of steel reinforcement shall be taken as:
4.1.4 Load transfer at horizontal connections 𝐸𝑠 = 200,000 MPa Equation 4-1
4.1.4.1 Walls, columns, and pilasters shall be
designed to resist loads, moments, and shears 4.2.2.2 Clay and concrete masonry
applied at intersections with horizontal members. 4.2.2.2.1 The design of clay and concrete masonry
4.1.4.2 Effect of lateral deflection and translation shall be based on the following modulus of
of members providing lateral support shall be elasticity values:
considered.
4.1.4.3 Devices used for transferring lateral
support from members that intersect walls, 𝐸 = 700𝑓′ for clay masonry Equation 4-2
�
columns, or pilasters shall be designed to resist 𝑚
the forces
involved. 𝐸𝑚 = 900𝑓′ �for concrete
masonry Equation 4-3
4.1.5 Other effects
Consideration shall be given to effects of forces
Or the chord modulus of elasticity taken between
and deformations due to prestressing, vibrations,
0.05 and 0.33 of the maximum compressive
impact, shrinkage, expansion, temperature
strength of each prism determined by test in
changes, creep, unequal settlement of supports,
accordance with the prism test method, Article 1.4
and differential movement.
B.3 of TMS 602/ACI 530.1/ASCE 6, and ASTM
4.1.6 Lateral load distribution E111.
Lateral loads shall be distributed to the structural 4.2.2.2.2 Modulus of rigidity of clay masonry and
system in accordance with member stiffnesses and concrete masonry shall be taken as:
shall comply with the requirements of this section.
𝐸𝑣 = 0.4𝐸𝑚 Equation 4-4

SBC 305-CR- 1
 CHAPTER 4—GENERAL ANALYSIS AND DESIGN

4.2.2.3 AAC masonry 4.3.1.1 Members shall be designed using section

4.2.2.3.1 Modulus of elasticity of AAC masonry properties based on the minimum net cross-
shall be taken as: sectional area of the member under consideration.
Section properties shall be based on specified
𝐸𝐴𝐴𝐶 = 888(𝑓′ )0.6 Equation 4-5 dimensions.
𝐴
4.3.1.2 In members designed for composite action,
4.2.2.3.2 Modulus of rigidity of AAC masonry stresses shall be calculated using section properties
shall be taken as: based on the minimum transformed net cross-
sectional area of the composite member. The
𝐸𝑣 = 0.4𝐸𝐴𝐴𝐶 Equation 4-6 transformed area concept for elastic analysis, in
which areas of dissimilar materials are transformed
4.2.2.4 Grout — Modulus of elasticity of grout
in accordance with relative elastic moduli ratios,
shall be taken as 500𝑓′.
� shall apply.
4.2.3 Coefficients of thermal expansion 4.3.2 Stiffness
Material type 𝑘𝑡 (mm/mm/℃) Calculation of stiffness based on uncracked section
is permissible. Use of the average net cross-
Clay masonry 7.2 × 10−6 sectional area of the member considered in
stiffness calculations is permitted.
Concrete masonry 8.1 × 10−6 4.3.3 Radius of gyration
AAC masonry 8.1 × 10−6 Radius of gyration shall be calculated using the
average net cross-sectional area of the member
4.2.4 Coefficient of moisture expansion considered.
4.3.4 Bearing area
Material type 𝑘𝑒 (mm/mm)
The bearing area, 𝐴𝑏𝑟, for concentrated loads shall
Clay masonry 3 × 10−4 not exceed the following:
(a)
A1√A2/A1
4.2.5 Coefficients of shrinkage (b)
2A1
Material type 𝑘𝑚 The area, 𝐴2, is the area of the lower base of the
largest frustum of a right pyramid or cone that has
Concrete masonry 0.5𝑠𝑙 the loaded area, 𝐴1, as its upper base, slopes at 45
degrees from the horizontal, and is wholly
Concrete masonry 0.8𝜀𝑐𝑠/100 contained within the support. For walls not laid in
running bond, area 𝐴2 shall terminate at head
where 𝜀𝑐𝑠 is determined in accordance with ASTM joints.
C1693.
4.4 —Connection to structural frames
4.2.6 Coefficients of creep
Masonry walls shall not be connected to structural
Material type 𝑘𝑐, per MPa frames unless the connections and walls are
designed to resist design interconnecting forces
Clay masonry 0.1 × 10−4 and to accommodate calculated deflections.
4.5 —Masonry not laid in running bond
Concrete masonry 0.36 × 10−4
For masonry not laid in running bond, the
AAC masonry 0.72 × 10 −4 minimum area of horizontal reinforcement shall be
0.00028 multiplied by the gross vertical cross-
4.3 —Section properties sectional area of the wall using specified
dimensions. Horizontal reinforcement shall be
4.3.1 Stress calculations placed at a maximum spacing of 1200 mm on
center in horizontal mortar joints or in bond
beams.

SBC 305-CR- 1
CHAPTER 4—GENERAL ANALYSIS AND DESIGN

SBC 305-CR- 2
 CHAPTER 5—STRUCTURAL

CHAPTER 5—STRUCTURAL ELEMENTS

5.1 —Masonry assemblies (c) Intersecting reinforced bond beams shall be

5.1.1 Intersecting walls provided at a maximum spacing of 1200 mm
on center. The area of reinforcement in each
5.1.1.1 Wall intersections shall meet one of the bond beam shall not be less than 210
following requirements: mm2/mm multiplied by the vertical spacing
(a) Design shall conform to the provisions of of the bond beams in meters. Reinforcement
Section 5.1.1.2. shall be developed on each side of the
(b) Transfer of shear between walls shall be intersection.
prevented. 5.1.2 Effective compressive width per bar
5.1.1.2 Design of wall intersection 5.1.2.1 For masonry not laid in running bond and
5.1.1.2.1 Masonry shall be in running bond. having bond beams spaced not more than 1200 mm
center-to-center, and for masonry laid in running
5.1.1.2.2 Flanges shall be considered effective in bond, the width of the compression area used to
resisting applied loads. calculate element capacity shall not exceed the least
5.1.1.2.3 The width of flange considered effective on of:
each side of the web shall be the smaller of the (a) Center-to-center bar spacing.
actual flange on either side of the web wall or the (b) Six multiplied by the nominal wall thickness.
following: (c) 1800 mm.
(a) 6 multiplied by the nominal flange thickness 5.1.2.2 For masonry not laid in running bond and
for unreinforced and reinforced masonry, having bond beams spaced more than 1200 mm
when the flange is in compression center-to-center, the width of the compression area
(b) 6 multiplied by the nominal flange thickness used to calculate element capacity shall not exceed
for unreinforced masonry, when the flange is the length of the masonry unit.
in flexural tension
(c) 0.75 multiplied by the floor-to-floor wall 5.1.3 Concentrated loads
height for reinforced masonry, when the 5.1.3.1 Concentrated loads shall not be distributed
flange is in flexural tension. over a length greater than the minimum of the
The effective flange width shall not extend past a following:
movement joint. (a) The length of bearing area plus the length
5.1.1.2.4 Design for shear, including the transfer of determined by considering the concentrated
shear at interfaces, shall conform to the requirements load to be dispersed along a 2 vertical: 1
of Section 8.2.6; or Section 8.3.5; or Section 9.2.6; or horizontal line. The dispersion shall
Section 9.3.4.1.2; or Section 11.3.4.1.2. terminate at half the wall height, a
movement joint, the end of the wall, or an
5.1.1.2.5 The connection of intersecting walls shall
opening, whichever provides the smallest
conform to one of the following requirements:
length.
(a) At least fifty percent of the masonry units at (b) The center-to-center distance between
the interface shall interlock. concentrated loads.
(b) Walls shall be anchored by steel connectors
5.1.3.2 For walls not laid in running bond,
grouted into the wall and meeting the
concentrated loads shall not be distributed across
following requirements:
head joints. Where concentrated loads acting on such
(1) Minimum size: 6.5 mm × 38 mm × 710
walls are applied to a bond beam, the concentrated
mm including 50-mm long, 90-degree
load is permitted to be distributed through the bond
bend at each end to form a U or Z shape.
beam, but shall not be distributed across head joints
(2) Maximum spacing: 1200 mm.
below the bond beams.

SBC 305-CR- 2
 CHAPTER 5—STRUCTURAL

5.1.4 Multiwythe masonry elements Unless a more detailed analysis is performed, the
Design of masonry composed of more than one following requirements shall be satisfied:
wythe shall comply with the provisions of Section (a) Collar joints shall not contain headers, grout,
5.1.4.1, and either 5.1.4.25.1.4.3 or 5.1.4.3. or mortar.
5.1.4.1 The provisions of Sections 5.1.4.2, and 5.1.4.3 (b) Gravity loads from supported horizontal
shall not apply to AAC masonry units and glass members shall be resisted by the wythe
masonry units. nearest to the center of span of the supported
member. Any resulting bending moment
5.1.4.2 Composite action about the weak axis of the masonry element
5.1.4.2.1 Multiwythe masonry designed for shall be distributed to each wythe in
composite action shall have collar joints either: proportion to its relative stiffness.
(c) Lateral loads acting parallel to the plane of
(a) crossed by connecting headers, or the masonry element shall be resisted only
(b) Filled with mortar or grout and connected by by the wythe on which they are applied.
wall ties. Transfer of stresses from such loads between
5.1.4.2.2 Headers used to bond adjacent wythes shall wythes shall be neglected.
meet the requirements of either Section 8.1.4.2 or (d) Lateral loads acting transverse to the plane
Section 9.1.7.2 and shall be provided as follows: of the masonry element shall be resisted by
all wythes in proportion to their relative
(a) Headers shall be uniformly distributed and flexural stiffnesses.
the sum of their cross-sectional areas shall (e) Specified distances between wythes shall not
be at least 4 percent of the wall surface area. exceed 100 mm unless a detailed tie analysis
(b) Headers connecting adjacent wythes shall be is performed.
embedded a minimum of 80 mm in each
wythe. 5.1.4.3.2 Wythes of masonry designed for non-
composite action shall be connected by ties meeting
5.1.4.2.3 Wythes not bonded by headers shall meet the requirements of Section 5.1.4.2.3 or by adjustable
the requirements of either Section 8.1.4.2 or Section ties. Where the cross wires of joint reinforcement are
9.1.7.2 and shall be bonded by non-adjustable ties
used as ties, the joint reinforcement shall be ladder-
provided as follows: type or tab-type. Ties shall be without cavity drips.

Wire size Minimum number of ties required Adjustable ties shall meet the following requirements:
(a) One tie shall be provided for each 0.16 m2
2
one per 0.25 m of masonry surface of masonry surface area.
WD 4.0
area (b) Horizontal and vertical spacing shall not
exceed 400 mm.
one per 0.42 m2 of masonry surface (c) Adjustable ties shall not be used when the
WD 5.0
area misalignment of bed joints from one wythe
to the other exceeds 30 mm.
(d) Maximum clearance between connecting
The maximum spacing between ties shall be 900 mm parts of the tie shall be 1.5 mm.
horizontally and 600 mm vertically. The use of (e) Pintle ties shall have at least two pintle legs
rectangular ties to connect masonry wythes of any of wire size WD 5.0.
type of masonry unit shall be permitted. The use of Z
ties to connect to a masonry wythe of hollow 5.2 —Beams
masonry units shall not be permitted. Cross wires of Design of beams shall meet the requirements of
joint reinforcement shall be permitted to be used Section 5.2.1 or Section 5.2.2. Design of beams shall
instead of ties. also meet the requirements of Section 8.3, Section
5.1.4.3 Non-composite action — The design of 9.3 or Section 11.3. Design requirements for
multiwythe masonry for non-composite action shall masonry beams shall apply to masonry lintels.
comply with Sections 5.1.4.3.1 and 5.1.4.3.2: 5.2.1 General beam design
5.1.4.3.1 Each wythe shall be designed to resist 5.2.1.1 Span length — Span length shall be in
individually the effects of loads imposed on it. accordance with the following:

SBC 305-CR- 2
 CHAPTER 5—STRUCTURAL

5.2.1.1.1 Span length of beams not built integrally calculated using the value for the modulus of rupture,
with supports shall be taken as the clear span plus 𝑓𝑟𝐴𝐴𝐶 , as given by Section 11.1.8.3.
depth of beam, but need not exceed the distance
between centers of supports. 5.2.1.4.3 Deflections of reinforced masonry beams
need not be checked when the span length does not
5.2.1.1.2 For determination of moments in beams exceed 8 multiplied by the effective depth to the
that are continuous over supports, span length shall reinforcement, 𝑑, in the masonry beam.
be taken as the distance between centers of supports.
5.2.2 Deep beams
5.2.1.2 Lateral support — The compression face of
beams shall be laterally supported at a maximum Design of deep beams shall meet the requirements of
spacing based on the smaller of: Section 5.2.1.2 and 5.2.1.3 in addition to the
requirements of 5.2.2.1 through 5.2.2.5.
(a) 32𝑏
5.2.2.1 Effective span length — The effective span
(b) 120𝑏2/𝑑
length 𝑙𝑒𝑓𝑓 shall be taken as the center to center
5.2.1.3 Bearing length — Length of bearing of distance between supports or 1.15 multiplied by the
beams on their supports shall be a minimum of 100 clear span. Whichever is smaller.
mm in the direction of span.
5.2.2.2 Internal lever arm — Unless determined by a
5.2.1.4 Deflections — Masonry beams shall be more comprehensive analysis, the internal lever arm,
designed to have adequate stiffness to limit 𝑧, shall be taken as:
deflections that adversely affect strength or
serviceability. (a) For simply supported spans.
𝑙𝑒𝑓𝑓
5.2.1.4.1 The calculated deflection of beams (1) When 1 ≤ <2
𝑑𝑣
providing vertical support to masonry designed in
accordance with Section 8.2, Section 9.2, Section 𝑧 = 0.2(𝑙𝑒𝑓𝑓 + 2𝑑𝑣) Equation 5-2a
11.2, Chapter 14, or Appendix A shall not exceed
𝑙/600 under unfactored dead plus live loads. 𝑙𝑒𝑓𝑓
(2) When <1
5.2.1.4.2 Deflection of masonry beams shall be 𝑑𝑣
calculated using the appropriate load-deflection
relationship considering the actual end conditions. 𝑧 = 0.6𝑙𝑒𝑓𝑓 Equation 5-2b
Unless stiffness values are obtained by a more (b) For continuous 𝑙spans
comprehensive analysis, immediate deflections shall (1) When 1 ≤
𝑒𝑓𝑓
<3
be calculated with an effective moment of inertia, 𝑑𝑣
𝐼𝑒𝑓𝑓 as follows:
𝑧 = 0.2(𝑙𝑒𝑓𝑓 + 1.5𝑑𝑣) Equation 5-3a
3 𝑙𝑒𝑓𝑓
𝑀 3 (2) When <1
𝑐𝑟 𝑀𝑐𝑟
𝐼𝑒𝑓𝑓 = ( [1 − ( ) ] ≤ 𝐼𝑛
+ 𝐼𝑐𝑟 5-1 𝑑𝑣
) 𝑀𝑎
𝐼𝑛 𝑀𝑎 𝑧 = 0.5𝑙𝑒𝑓𝑓 Equation 5-3b
For continuous beams, 𝐼𝑒𝑓𝑓 shall be permitted to be
taken as the average of values obtained from 5-1 for 5.2.2.3 Flexural reinforcement — Distributed
the critical positive and negative moment regions. horizontal flexural reinforcement shall be provided
in the tension zone of the beam for a depth equal to
For beams of uniform cross-section, 𝐼𝑒𝑓𝑓 shall be
half of the beam depth, 𝑑𝑣. The maximum
permitted to be taken as the value obtained from 5-1
at midspan for simple spans and at the support for spacing of
cantilevers. For masonry designed in accordance distributed horizontal flexural reinforcement shall not
with Chapter 8, the cracking moment, 𝑀𝑐𝑟, shall be exceed one-fifth of the beam depth, 𝑑𝑣 nor 400 mm.
Joint reinforcement shall be permitted to be used as
calculated using the allowable flexural tensile stress
distributed horizontal flexural reinforcement in deep
taken from Table 8.1 multiplied by a factor of 2.5.
beams. Horizontal flexural reinforcement shall be
For masonry designed in accordance with Chapter 9,
anchored to develop the yield strength of the
the cracking moment, 𝑀𝑐𝑟, shall be calculated using
reinforcement at the face of supports.
the value for the modulus of rupture, 𝑓𝑟, taken from
Table 5.2.2.4 Minimum shear reinforcement — The
9.1. For masonry designed in accordance with following provisions shall apply when shear
CHAPTER 11, the cracking moment, 𝑀𝑐𝑟, shall be reinforcement is required in accordance with Section
8.3.5, Section 9.3.4.1.2, or Section 11.3.4.1.2.

SBC 305-CR- 2
 CHAPTER 5—STRUCTURAL

(a) The minimum area of vertical shear the lateral tie from such a laterally supported
reinforcement shall be 0.0007bdv. bar. Lateral ties shall be placed in either a
(b) Horizontal shear reinforcement shall have mortar joint or in grout. Where longitudinal
cross-sectional area equal to or greater than bars are located around the perimeter of a
one half the area of the vertical shear circle, a complete circular lateral tie is
reinforcement. Such reinforcement shall be permitted. Lap length for circular ties shall
equally distributed on both side faces of the be 48 tie diameters.
beam when the nominal width of the beam is (d) Lateral ties shall be located vertically not
greater than 200 mm. more than one-half lateral tie spacing above
(c) The maximum spacing of shear the top of footing or slab in any story, and
reinforcement shall not exceed one-fifth the shall be spaced not more than one-half a
beam depth, dv nor 400 mm. lateral tie spacing below the lowest
5.2.2.5 Total reinforcement — The sum of the cross- horizontal reinforcement in beam, girder,
sectional areas of horizontal and vertical slab, or drop panel above
reinforcement shall be at least 0.001 multiplied by 5.3.2 Lightly loaded columns
the gross cross-sectional area, 𝑏𝑑𝑣 of the deep
beam, Masonry columns used only to support light frame
using specified dimensions. roofs of carports, porches, sheds or similar structures
assigned to Seismic Design Category A, B, or C,
5.3 —Columns which are subject to unfactored gravity loads not
Design of columns shall meet the requirements of exceeding 8,900 N acting within the cross-sectional
Section 5.3.1 or Section 5.3.2. Design of columns dimensions of the column are permitted to be
shall also meet the requirements of Section 8.3, or constructed as follows:
Section 9.3, or Section 11.3. (a) Minimum side dimension shall be 200 mm
5.3.1 General column design nominal.
(b) Height shall not exceed 3.50 m.
5.3.1.1 Dimensional limits — Dimensions shall be (c) Cross-sectional area of longitudinal
in accordance with the following: reinforcement shall not be less than
(a) The distance between lateral supports of a 129 mm2 centered in the column.
column shall not exceed 99 multiplied by the (d) Columns shall be fully grouted.
least radius of gyration, r. 5.4 —Pilasters
(b) Minimum side dimension shall be 200 mm
nominal. Walls interfacing with pilasters shall not be
considered as flanges, unless the construction
5.3.1.2 Construction — Columns shall be fully requirements of Sections 5.1.1.2.1 and 5.1.1.2.5 are
grouted. met. When these construction requirements are met,
5.3.1.3 Vertical reinforcement — Vertical the pilaster's flanges shall be designed in accordance
reinforcement in columns shall not be less than with Sections 5.1.1.2.2 through 5.1.1.2.4.
0.0025𝐴𝑛 nor exceed 0.04𝐴𝑛. The minimum
5.5 —Corbels
number of bars shall be four.
5.5.1 Load-bearing corbels
5.3.1.4 Lateral ties — Lateral ties shall conform to
the following: Load-bearing corbels shall be designed in
accordance with Chapter 8 or Chapter 9.
(a) Vertical reinforcement shall be enclosed by
lateral ties at least 6 mm in diameter. 5.5.2 Non-load-bearing — corbels Non-load-
(b) Vertical spacing of lateral ties shall not bearing corbels shall be designed in accordance with
exceed 16 longitudinal bar diameters, 48 Chapter 8 or Chapter 9 or or detailed as follows:
lateral tie bar or wire diameters, or least
(a) Solid masonry units or hollow units filled
cross-sectional dimension of the member.
with mortar or grout shall be used.
(c) Lateral ties shall be arranged so that every
(b) The maximum projection beyond the face of
corner and alternate longitudinal bar shall
the wall shall not exceed:
have lateral support provided by the corner
(1) One-half the wall thickness for
of a lateral tie with an included angle of not
multiwythe walls bonded by mortar or
more than 135 degrees. No bar shall be
farther than 150 mm clear on each side along

SBC 305-CR- 2
CHAPTER 5—STRUCTURAL

grout and wall ties or masonry headers, (1) One-half the nominal unit height.
or (2) One-third the nominal thickness of the
(2) One-half the wythe thickness for single unit or wythe.
wythe walls, masonry bonded hollow (d) The back surface of the corbelled section
walls, multiwythe walls with open collar shall remain within 25 mm of plane.
joints, and veneer walls.
(c) The maximum projection of one unit shall
not exceed:

SBC 305-CR- 2
 CHAPTER 6—REINFORCEMENT, METAL ACCESSORIES, AND ANCHOR

CHAPTER 6—REINFORCEMENT, METAL ACCESSORIES, AND

ANCHOR BOLTS

(a) Masonry face exposed to earth or weather:

6.1 —Details of reinforcement and metal
50 mm for bars larger than Dia 16; 38 mm
accessories for Dia 16 bars or smaller.
6.1.1 Embedment (b) Masonry not exposed to earth or weather: 38
mm.
Reinforcing bars shall be embedded in grout.
6.1.4.2 Longitudinal wires of joint reinforcement
6.1.2 Size of reinforcement shall be fully embedded in mortar or grout with a
6.1.2.1 The maximum size of reinforcement used in minimum cover of 16 mm when exposed to earth or
masonry shall be Dia 36. weather and 13 mm when not exposed to earth or
weather. Joint reinforcement shall be stainless steel
6.1.2.2 The diameter of reinforcement shall not or protected from corrosion by hot-dipped
exceed one-half the least clear dimension of the cell, galvanized coating or epoxy coating when used in
bond beam, or collar joint in which it is placed. masonry exposed to earth or weather and in interior
6.1.2.3 Longitudinal and cross wires of joint walls exposed to a mean relative humidity exceeding
reinforcement shall have a minimum wire size of 75 percent. All other joint reinforcement shall be
WD 4.0 and a maximum wire size of one-half the mill galvanized, hot-dip galvanized, or stainless
joint thickness. steel.
6.1.3 Placement of reinforcement 6.1.4.3 Wall ties, sheet-metal anchors, steel plates
and bars, and inserts exposed to earth or weather, or
6.1.3.1 The clear distance between parallel bars shall exposed to a mean relative humidity exceeding 75
not be less than the nominal diameter of the bars, nor percent shall be stainless steel or protected from
less than 25 mm. corrosion by hot-dip galvanized coating or epoxy
6.1.3.2 In columns and pilasters, the clear distance coating. Wall ties, anchors, and inserts shall be mill
between vertical bars shall not be less than one and galvanized, hot-dip galvanized, or stainless steel for
one-half multiplied by the nominal bar diameter, nor all other cases. Anchor bolts, steel plates, and bars
less than 38 mm. not exposed to earth, weather, nor exposed to a mean
relative humidity exceeding 75 percent, need not be
6.1.3.3 The clear distance limitations between bars coated.
required in Sections 6.1.3.1 and 6.1.3.2 shall also
apply to the clear distance between a contact lap 6.1.5 Standard hooks
splice and adjacent splices or bars. Standard hooks shall consist of the following:
6.1.3.4 Groups of parallel reinforcing bars bundled (a) 180-degree bend plus a minimum 4db
in contact to act as a unit shall be limited to two in extension, but not less than 65 mm, at free
any one bundle. Individual bars in a bundle cut off end of bar;
within the span of a member shall terminate at points (b) 90-degree bend plus a minimum 12db
at least 40 bar diameters apart. extension at free end of bar; or
6.1.3.5 Reinforcement embedded in grout shall have (c) for stirrup and tie hooks for a Dia 16 bar and
a thickness of grout between the reinforcement and smaller, either a 90-degree or 135-degree
masonry units not less than 7 mm for fine grout or bend plus a minimum 6db extension, but not
13 mm for coarse grout. less than 65 mm, at free end of bar.
6.1.4 Protection of reinforcement and metal 6.1.6 Minimum bend diameter for reinforcing bars
accessories The diameter of bend measured on the inside of
6.1.4.1 Reinforcing bars shall have a masonry cover reinforcing bars, other than for stirrups and ties, shall
not less than the following: not be less than values specified in Table 6.1.

SBC 305-CR- 2
 CHAPTER 6—REINFORCEMENT, METAL ACCESSORIES, AND ANCHOR

6.2 —Anchor bolts 6.2.3 Projected area for shear

Headed and bent-bar anchor bolts shall conform to The projected area of headed and bent-bar anchor
the provisions of Sections 6.2.1 through 6.2.7. bolts loaded in shear, 𝐴𝑝𝑣, shall be determined from
6.2.1 Placement 6-2.
Headed and bent-bar anchor bolts shall be embedded 𝜋𝑙2
in grout. Anchor bolts of 7 mm diameter are 𝐴𝑝𝑣 =
𝑏𝑒 6-2
permitted to be placed in mortar bed joints that are 2
at least 13
mm in thickness and, for purposes of application of The portion of projected area overlapping an open
the provisions of Sections 6.2, 8.1.3 and 9.1.6, are cell, or open head joint, or that lies outside the
permitted to be considered as if they are embedded masonry shall be deducted from the value of 𝐴𝑝𝑣
in grout. Anchor bolts placed in the top of grouted calculated using 6-2. Where the projected areas of
cells and bond beams shall be positioned to maintain anchor bolts overlap, the value of 𝐴𝑝𝑣 calculated
a minimum of 7 mm of fine grout between the bolts using 6-2 shall be adjusted so that no portion of
and the masonry unit or 13 mm of coarse grout masonry is included more than once.
between the bolts and the masonry unit. Anchor
bolts placed in drilled holes in the face shells of 6.2.4 Effective embedment length for headed
hollow masonry units shall be permitted to contact anchor bolts
the masonry unit where the bolt passes through the The effective embedment length for a headed anchor
face shell, but the portion of the bolt that is within bolt, 𝑙𝑏, shall be the length of the embedment
the grouted cell shall be positioned to maintain a measured perpendicular from the masonry surface to
minimum of 7 mm of fine grout between the head or the compression bearing surface of the anchor head.
bent leg of each bolt and the masonry unit or 13 mm
of coarse grout between the head or bent leg of each 6.2.5 Effective embedment length for bent-bar
bolt and the masonry unit. The clear distance anchor bolts
between parallel anchor bolts shall not be less than The effective embedment for a bent-bar anchor bolt,
the nominal diameter of the anchor bolt, nor less 𝑙𝑏, shall be the length of embedment measured
than 25 mm. perpendicular from the masonry surface to the
6.2.2 Projected area for axial tension compression bearing surface of the bent end, minus
The projected area of headed and bent-bar anchor
bolts loaded in axial tension, 𝐴 one anchor bolt diameter.
𝑝𝑡 , shall be determined
by 6-1. 6.2.6 Minimum permissible effective embedment
length
𝐴𝑝𝑡 = 𝜋𝑙2 6-1
� The minimum permissible effective embedment
length for headed and bent-bar anchor bolts shall be
The portion of projected area overlapping an open the greater of 4 bolt diameters or 50 mm.
cell, or open head joint, or that lies outside the
masonry shall be deducted from the value of 𝐴𝑝𝑡 6.2.7 Anchor bolt edge distance
calculated using 6-1. Where the projected areas of Anchor bolt edge distance, 𝑙𝑏𝑒, shall be measured in
anchor bolts overlap, the value of 𝐴𝑝𝑡 calculated the direction of load from the edge of masonry to
using 6-1 shall be adjusted so that no portion of center of the cross section of anchor bolt.
masonry is included more than once.

SBC 305-CR- 2
CHAPTER 6—REINFORCEMENT, METAL ACCESSORIES, AND ANCHOR

TABLES OF CHAPTER 6

Table 6.1: Minimum diameters of bend

Bar size and type Minimum diameter

Dia 10 through Dia 22 (Grade 280) 5 bar diameters

Dia 10 through Dia 25 (Grade 350 or 420) 6 bar diameters

Dia 28, Dia 32, and Dia 36 (Grade 350 or 420) 8 bar diameters

Table 6.2: Physical properties of steel reinforcing wire

Designation Nominal Nominal Nominal Area (As, mm2) per meter
diameter, area, mass, Center-to-center spacing, mm
2
mm mm kg/m 50 75 100 150 200 250 300 350 400
WD 4.0 4 12.6 0.099 252 168 126 84 63 50 42 36 32
WD 4.5 4.5 15.9 0.125 318 212 159 106 80 64 53 45 40
WD 5.0 5 19.6 0.154 392 261 196 131 98 78 65 56 49
WD 5.5 5.5 23.8 0.187 476 317 238 159 119 95 79 68 60
WD 6.0 6 28.3 0.222 566 377 283 189 142 113 94 81 71
WD 6.5 6.5 33.2 0.26 664 443 332 221 166 133 111 95 83
WD 7.0 7 38.5 0.302 770 513 385 257 193 154 128 110 96
WD 7.5 7.5 44.2 0.347 884 589 442 295 221 177 147 126 111
WD 8.0 8 50.3 1006 671 503 335 252 201 168 144 126
WD 8.5 8.5 56.7 0.445 1134 756 567 378 284 227 189 162 142
WD 9.0 9 63.6 0.499 1272 848 636 424 318 254 212 182 159
WD 9.5 9.5 70.9 0.556 1418 945 709 473 355 284 236 203 177
WD 10.0 10 78.5 0.617 1570 1047 785 523 393 314 262 224 196
WD 10.5 10.5 86.6 0.68 1732 1155 866 577 433 346 289 247 217
WD 11.0 11 95 0.746 1900 1267 950 633 475 380 317 271 238
WD 11.5 11.5 103.9 0.815 2078 1385 1039 693 520 416 346 297 260
WD 12.0 12 113.1 0.888 2262 1508 1131 754 566 452 377 323 283

SBC 305-CR- 2
CHAPTER 6—REINFORCEMENT, METAL ACCESSORIES, AND ANCHOR

Table 6.3: Physical properties of steel reinforcing bars

Bar designation Nominal Nominal Nominal mass,

diameter, mm area, mm2 kg/m
Dia 6 6 28 0.222
Dia 8 8 50 0.395
Dia 10 10 79 0.617
Dia 12 12 113 0.888
Dia 14 14 154 1.21
Dia 16 16 201 1.58
Dia 18 18 254 2.00
Dia 20 20 314 2.47
Dia 22 22 380 2.98
Dia 25 25 491 3.85
Dia 28 28 616 4.83
Dia 32 32 804 6.31
Dia 36 36 1018 7.99
Dia 40 40 1257 9.87
Dia 45 45 1590 12.5
Dia 50 50 1963 15.4

SBC 305-CR- 2
 CHAPTER 7—SEISMIC DESIGN

CHAPTER 7—SEISMIC DESIGN REQUIREMENTS

7.1 —Scope
7.3.2 Participating elements — Masonry walls
that are part of the seismic-force-resisting system
The seismic design requirements of Chapter 7 shall shall be classified as participating elements and shall
apply to the design and construction of masonry, comply with the requirements of Section 7.3.2.1,
except glass unit masonry and masonry veneer. 7.3.2.2, 7.3.2.3, 7.3.2.4, 7.3.2.5, 7.3.2.6, 7.3.2.7, 7.3.2.8,
or 7.3.2.9.
7.2 —General analysis
7.3.2.1 Empirical design of masonry shear walls —
7.2.1 Element interaction — The interaction of Empirical design of shear walls shall comply with
structural and nonstructural elements that affect the the requirements of Section A.3.
linear and nonlinear response of the structure to
earthquake motions shall be considered in the 7.3.2.2 Ordinary plain (unreinforced) masonry shear
analysis. walls — Design of ordinary plain (unreinforced)
masonry shear walls shall comply with the
7.2.2 Load path — Structural masonry elements requirements of Section 8.2 or Section 9.2.
that transmit forces resulting from earthquakes to the
foundation shall comply with the requirements of 7.3.2.3 Detailed plain (unreinforced) masonry shear
Chapter 7. walls — Design of detailed plain (unreinforced)
masonry shear walls shall comply with the
7.2.3 Anchorage design — Load path connections requirements of Section 8.2 or Section 9.2, and shall
and minimum anchorage forces shall comply with comply with the requirements of Section 7.3.2.3.1.
the requirements of SBC 301.
7.3.2.3.1 Minimum reinforcement requirements —
7.2.4 Drift limits — Under loading combinations Vertical reinforcement of at least 129 mm2 in cross-
that include earthquake, masonry structures shall be sectional area shall be provided at comers, within
designed so the calculated story drift, ∆, does not 400 mm of each side of openings, within 200 mm of
exceed the allowable story drift, ∆𝑎, obtained from each side of movement joints, within 200 mm of the
SBC 301. ends of walls, and at a maximum spacing of 3000
It shall be permitted to assume that the following mm on center.
shear wall types comply with the story drift limits of Vertical reinforcement adjacent to openings need not
SBC 301: empirical, ordinary plain (unreinforced), be provided for openings smaller than 400 mm,
detailed plain (unreinforced), ordinary reinforced, unless the distributed reinforcement is interrupted by
intermediate reinforced, ordinary plain such openings.
(unreinforced) AAC masonry shear walls, and
detailed plain (unreinforced) AAC masonry shear Horizontal reinforcement shall consist of at least two
walls. longitudinal wires of WD 4.0 joint reinforcement
spaced not more than 400 mm on center, or at least
7.3 —Element classification 129 mm2 in cross-sectional area of bond beam
Masonry elements shall be classified in accordance reinforcement spaced not more than 3000 mm on
with Section 7.3.1 and 7.3.2 as either participating or center. Horizontal reinforcement shall also be
nonparticipating elements of the seismic-force- provided: at the bottom and top of wall openings and
resisting system. shall extend at least 625 mm but not less than 40 bar
diameters past the opening; continuously at
7.3.1 Nonparticipating elements — Masonry structurally connected roof and floor levels; and
elements that are not part of the seismic-force- within 400 mm of the top of walls.
resisting system shall be classified as nonparticipating
elements and shall be isolated in their own plane Horizontal reinforcement adjacent to openings need
from the seismic force-resisting system except as not be provided for openings smaller than 400 mm,
required for gravity support. Isolation joints and unless the distributed reinforcement is interrupted by
connectors shall be designed to accommodate the such openings.
design story drift.

SBC 305-CR- 3
 CHAPTER 7—SEISMIC DESIGN

7.3.2.4 Ordinary reinforced masonry shear walls — sectional area of horizontal

Design of ordinary reinforced masonry shear walls reinforcement shall be at least 0.0015
shall comply with the requirements of Section 8.3 or multiplied by the gross cross-sectional
Section 9.3, and shall comply with the requirements area of the wall, using specified
of Section 7.3.2.3.1. dimensions.
7.3.2.5 Intermediate reinforced masonry shear walls (d) Shear reinforcement shall be anchored
— Design of intermediate reinforced masonry shear around vertical reinforcing bars with a
walls shall comply with the requirements of Section standard hook.
8.3 or Section 9.3. Reinforcement detailing shall also (e) Mechanical splices in flexural reinforcement
comply with the requirements of Section 7.3.2.3.1, in plastic hinge zones shall develop the
except that the spacing of vertical reinforcement specified tensile strength of the spliced bar.
shall not exceed 1200 mm. (f) Masonry not laid in running bond shall be
fully grouted and shall be constructed of
7.3.2.6 Special reinforced masonry shear walls — hollow open-end units or two wythes of
Design of special reinforced masonry shear walls solid units.
shall comply with the requirements of Section 8.3,
Section 9.3, or APPENDIX C. Reinforcement
detailing shall also comply with the requirements of 7.3.2.6.1 Shear capacity design
Section 7.3.2.3.1 and the following: 7.3.2.6.1.1 When designing special reinforced
(a) The maximum spacing of vertical masonry shear walls to resist in-plane forces in
reinforcement shall be the smallest of one- accordance with Section 9.3, the design shear
third the length of the shear wall, one-third strength, 𝜙𝑉𝑛, shall exceed the shear corresponding
the height of the shear wall, and 1200 mm to
for masonry laid in running bond and 600 the development of 1.25 times the nominal flexural
mm for masonry not laid in running bond. strength, 𝑀𝑛, of the element, except that the nominal
(b) The maximum spacing of horizontal shear strength, 𝑉𝑛, need not exceed 2.5 times
reinforcement required to resist in-plane required shear strength, 𝑉𝑢.
shear shall be uniformly distributed, shall be 7.3.2.6.1.2 When designing special reinforced
the smaller of one-third the length of the masonry shear walls in accordance with Section 8.3,
shear wall and one-third the height of the the shear or diagonal tension stress resulting from in-
shear wall, and shall be embedded in grout. plane seismic forces shall be increased by a factor of
The maximum spacing of horizontal 1.5. The 1.5 multiplier need not be applied to the
reinforcement shall not exceed 1200 mm for overturning moment.
masonry laid in running bond and 600 mm
for masonry not laid in running bond. 7.3.2.7 Ordinary plain (unreinforced) AAC masonry
(c) The minimum cross-sectional area of shear walls — Design of ordinary plain
vertical reinforcement shall be one-third of (unreinforced) AAC masonry shear walls shall
the required shear reinforcement. The sum comply with the requirements of Section 11.2 and
of the cross-sectional area of horizontal and Section 7.3.2.7.1.
vertical reinforcement shall be at least 0.002 7.3.2.7.1 Anchorage of floor and roof diaphragms in
multiplied by the gross cross-sectional area AAC masonry structures — Floor and roof
of the wall, using specified dimensions. diaphragms in AAC masonry structures shall be
(1) For masonry laid in running bond, the anchored to a continuous grouted bond beam
minimum cross-sectional area of reinforced with at least two longitudinal reinforcing
reinforcement in each direction shall be bars, having a total cross-sectional area of at least
at least 0.0007 multiplied by the gross 260 mm2.
cross-sectional area of the wall, using
specified dimensions. 7.3.2.8 Detailed plain (unreinforced) AAC masonry
(2) For masonry not laid in running bond, shear walls — Design of detailed plain
the minimum cross-sectional area of (unreinforced) AAC masonry shear walls shall
vertical reinforcement shall be at least comply with the requirements of Section 11.2 and
0.0007 multiplied by the gross cross- Sections 7.3.2.7.1 and 7.3.2.8.1.
sectional area of the wall, using 7.3.2.8.1 Minimum reinforcement requirements —
specified dimensions. The Vertical reinforcement of at least 129 mm2 shall be
minimum cross- provided within 600 mm of each side of openings,

SBC 305-CR- 3
 CHAPTER 7—SEISMIC DESIGN

within 200 mm of movement joints, and within 600 7.4.1.2 Design of participating elements —
mm of the ends of walls. Vertical reinforcement Participating masonry elements shall be designed to
adjacent to openings need not be provided for comply with the requirements of CHAPTER 8,
openings smaller than 400 mm, unless the CHAPTER 9, CHAPTER 11, CHAPTER 14,
distributed reinforcement is interrupted by such APPENDIX A, or APPENDIX B. Masonry shear walls
openings. Horizontal reinforcement shall be shall be designed to comply with the requirements of
provided at the bottom and top of wall openings and Section 7.3.2.1, 7.3.2.2, 7.3.2.3, 7.3.2.4, 7.3.2.5,
shall extend at least 600 mm but not less than 40 bar 7.3.2.6, 7.3.2.7, 7.3.2.8, or 7.3.2.9.
diameters past the opening. Horizontal
reinforcement adjacent to openings need not be 7.4.2 Seismic Design Category B requirements —
provided for openings smaller than 400 mm, unless Masonry elements in structures assigned to Seismic
the distributed reinforcement is interrupted by such Design Category B shall comply with the
openings. requirements of Section 7.4.1 and with the additional
requirements of Section 7.4.2.1.
7.3.2.9 Ordinary reinforced AAC masonry shear
walls — Design of ordinary reinforced AAC 7.4.2.1 Design of participating elements —
masonry shear walls shall comply with the Participating masonry elements shall be designed to
requirements of Section 11.3 and Sections 7.3.2.7.1 comply with the requirements of CHAPTER 8,
and 7.3.2.8.1. CHAPTER 9, CHAPTER 11, or APPENDIX B.
Masonry shear walls shall be designed to comply
7.3.2.9.1 Shear capacity design — The design shear with the requirements of Section 7.3.2.2, 7.3.2.3,
strength, 𝜙𝑉𝑛, shall exceed the shear corresponding
7.3.2.4, 7.3.2.5, 7.3.2.6, 7.3.2.7, 7.3.2.8, or 7.3.2.9.
to the development of 1.25 times the nominal
flexural strength, 𝑀𝑛, of the element, except that the 7.4.3 Seismic Design Category C requirements —
nominal shear strength, 𝑉𝑛, need not exceed 2.5 Masonry elements in structures assigned to Seismic
times required shear strength, 𝑉𝑢. Design Category C shall comply with the
requirements of Section 7.4.2 and with the additional
7.3.2.10 Ordinary plain (unreinforced) prestressed
requirements of Section 7.4.3.1 and 7.4.3.2.
masonry shear walls — Design of plain
(unreinforced) prestressed masonry shear walls is 7.4.3.1 Design of nonparticipating elements —
beyond the scope of the current SBC code. Nonparticipating masonry elements shall comply
with the requirements of Section 7.3.1 and CHAPTER
7.3.2.11 Intermediate reinforced prestressed
8, CHAPTER 9, CHAPTER 11, APPENDIX A, or
masonry shear walls — Design of intermediate
APPENDIX B. Nonparticipating masonry elements,
reinforced prestressed masonry shear walls is
except those constructed of AAC masonry, shall be
beyond the scope of the current SBC code.
reinforced in either the horizontal or vertical
7.3.2.12 Special reinforced prestressed masonry direction in accordance with the following:
shear walls — Design of special reinforced
(a) Horizontal reinforcement — Horizontal
prestressed masonry shear walls is beyond the scope
reinforcement shall consist of at least two
of the current SBC code.
longitudinal wires of WD 4.0 bed joint
7.4 —Seismic Design Category reinforcement spaced not more than 400 mm
requirements on center for walls greater than 100 mm in
width and at least one longitudinal WD 4.0
The design of masonry elements shall comply with wire spaced not more than 400 mm on center
the requirements of Sections 7.4.1 through 7.4.4 for walls not exceeding 100 mm in width or
based on the Seismic Design Category as defined in at least one Dia 14 bar spaced not more than
SBC 301. 1200 mm on center. Where two longitudinal
7.4.1 Seismic Design Category A requirements — wires of joint reinforcement are used, the
Masonry elements in structures assigned to Seismic space between these wires shall be the
Design Category A shall comply with the widest that the mortar joint will
requirements of Sections 7.1, 7.2, 7.4.1.1, and 7.4.1.2. accommodate. Horizontal reinforcement
shall be provided within 400 mm of the top
7.4.1.1 Design of nonparticipating elements — and bottom of these masonry walls.
Nonparticipating masonry elements shall comply (b) Vertical reinforcement — Vertical
with the requirements of Section 7.3.1 and CHAPTER reinforcement shall consist of at least one
8, CHAPTER 9, CHAPTER 11, CHAPTER 14, Dia
APPENDIX A, or APPENDIX B. 14 bar spaced not more than 3000 mm.

SBC 305-CR- 3
 CHAPTER 7—SEISMIC DESIGN

Vertical reinforcement shall be located within nominal depth of the beam. The minimum transverse
400 mm of the ends of masonry walls. reinforcement ratio shall be 0.0015.
7.4.3.2 Design of participating elements — 7.4.4 Seismic Design Category D requirements —
Participating masonry elements shall be designed to Masonry elements in structures assigned to Seismic
comply with the requirements of Section 8.3, 9.3, Design Category D shall comply with the
11.3, or APPENDIX B. Masonry shear walls shall be requirements of Section 7.4.3 and with the additional
designed to comply with the requirements of Section requirements of Sections 7.4.4.1 and 7.4.4.2.
7.3.2.4, 7.3.2.5, 7.3.2.6, or 7.3.2.9.
Exception: Design of participating elements of AAC
7.4.3.2.1 Connections to masonry columns — Where masonry shall comply with the requirements of
anchor bolts are used to connect horizontal elements Section 7.4.3.
to the tops of columns, anchor bolts shall be placed
within lateral ties. Lateral ties shall enclose both the 7.4.4.1 Design of nonparticipating elements -
vertical bars in the column and the anchor bolts. Nonparticipating masonry elements shall comply
There shall be a minimum of two Dia 14 lateral ties with the requirements of CHAPTER 8, CHAPTER 9,
provided in the top 125 mm of the column. CHAPTER 11, or APPENDIX B. Nonparticipating
masonry elements, except those constructed of AAC
7.4.3.2.2 Anchorage of floor and roof diaphragms in masonry, shall be reinforced in either the horizontal
AAC masonry structures — Seismic load between or vertical direction in accordance with the
floor and roof diaphragms and AAC masonry shear following:
walls shall be transferred through connectors
embedded in grout and designed in accordance with (a) Horizontal reinforcement — Horizontal
Section 4.1.4. reinforcement shall comply with Section
7.4.3.1(a).
7.4.3.2.3 Material requirements — ASTM C34, (b) Vertical reinforcement — Vertical
structural clay load-bearing wall tiles, shall not be reinforcement shall consist of at least one
used as part of the seismic-force-resisting system. Dia
7.4.3.2.4 Lateral stiffness — At each story level, at 14 bar spaced not more than 1200 mm.
least 80 percent of the lateral stiffness shall be Vertical reinforcement shall be located within
provided by seismic-force-resisting walls. Along each 400 mm of the ends of masonry walls.
line of lateral resistance at a particular story level, at 7.4.4.2 Design of participating elements — Masonry
least 80 percent of the lateral stiffness shall be shear walls shall be designed to comply with the
provided by seismic-force-resisting walls. Where requirements of Section 7.3.2.6 or 7.3.2.9.
seismic loads are determined based on a seismic
response modification factor, 𝑅, not greater than 1.5, 7.4.4.2.1 Minimum reinforcement for masonry
piers and columns shall be permitted to be used to columns — Lateral ties in masonry columns shall be
provide seismic load resistance. spaced not more than 200 mm on center and shall be
at least 9.5 mm diameter. Lateral ties shall be
7.4.3.2.5 Design of columns, pilasters, and beams embedded in grout.
supporting discontinuous elements — Columns and
pilasters that are part of the seismic-force resisting 7.4.4.2.2 Material requirements — Fully grouted
system and that support reactions from participating elements shall be designed and
discontinuous stiff elements shall be provided with specified with Type S or Type M cement-lime
transverse reinforcement spaced at no more than mortar, masonry cement mortar, or mortar cement
one-fourth of the least nominal dimension of the mortar. Partially grouted participating elements shall
column or pilaster. The minimum transverse be designed and specified with Type S or Type M
reinforcement ratio shall be 0.0015. Beams cement-lime mortar or mortar cement mortar
supporting reactions from discontinuous walls shall 7.4.4.2.3 Lateral tie anchorage — Standard hooks
be provided with transverse reinforcement spaced at for lateral tie anchorage shall be either a 135-degree
no more than one-half of the standard hook or a 180-degree standard hook.

SBC 305-CR- 3
 CHAPTER 7—SEISMIC DESIGN

TABLES OF CHAPTER 7

Table 7.1: Requirements for Masonry Shear Walls Based on Shear Wall Designation1
Reinforcement
Shear Wall Designation Design Methods Permitted In
Requirements
Empirical Design of Masonry Section A.3 None SDC A
Shear Walls
Ordinary Plain (Unreinforced) Section 8.2 or None SDC A and B
Masonry Shear Walls Section 9.2
Detailed Plain (Unreinforced) Section 8.2 or Section 7.3.2.3.1 SDC A and B
Masonry Shear Walls Section 9.2
Ordinary Reinforced Masonry Section 8.3 or Section 7.3.2.3.1 SDC A, B, and C
Shear Walls Section 9.3
Intermediate Reinforced Section 8.3 or Section 7.3.2.5 SDC A, B, and C
Masonry Shear Walls Section 9.3
Special reinforced masonry shear Section 8.3 or Section 7.3.2.6 SDC A, B, C, and D
walls Section 9.3
Ordinary Plain (Unreinforced) Section 7.3.2.7.1 SDC A and B
AAC Masonry Shear Walls Section 11.2

Detailed Plain (Unreinforced) Section 11.2 Section 7.3.2.8.1 SDC A and B

AAC Masonry Shear Walls
Ordinary Reinforced AAC Section 11.3 Section 7.3.2.9 SDC A, B, C, and D
masonry shear walls
1
Section and Chapter references in this table refer to Code Sections and Chapters.

SBC 305-CR- 3
PART 3—ENGINEERED DESIGN

PART 3—ENGINEERED DESIGN METHOD

SBC 305-CR- 3
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

CHAPTER 8—ALLOWABLE STRESS DESIGN OF MASONRY

8.1 —General the smaller of the values determined by Equation 8-1

8.1.1 Scope and Equation 8-2.

This chapter provides requirements for allowable

𝐵𝑎𝑏 = 0.104𝐴𝑝𝑡√𝑓′ Equation 8-1
stress design of masonry. Masonry designed in �
accordance with this chapter shall comply with the
𝐵𝑎𝑠 = 0.6𝐴𝑏𝑓𝑦 Equation 8-2
requirements of Part 1, Part 2, Sections 8.1.2
through 8.1.6, and either Section 8.2 or 8.3.
8.1.3.3.1.2 Allowable axial tensile load of bent-bar
8.1.2 Design strength anchor bolts — The allowable axial tensile load,
𝐵𝑎, for bent-bar anchor bolts embedded in grout
Calculated stresses shall not exceed the allowable shall
stress requirements of this Chapter.
be the smallest of the values determined by
Equation 8-3,
8.1.3 Anchor bolts embedded in grout
8.1.3.1 Design requirements — Anchor bolts shall 𝐵𝑎 = 0.104𝐴 𝑝𝑡 √𝑓
′
Equation 8-3
�
𝑏
be designed using either the provisions of Section 𝐵 = 0.6𝑓′ 𝑒 𝑑
8.1.3.2 or, for headed and bent-bar anchor bolts, by 𝑎𝑝 𝑚 𝑏 𝑏
Equation 8-4
the provisions of Section 8.1.3.3. +0.83𝜋(𝑙𝑏 + 𝑒𝑏 + 𝑑𝑏)𝑑𝑏
8.1.3.2 Allowable loads determined by test
𝐵𝑎𝑠 = 0.6𝐴𝑏𝑓𝑦 Equation 8-5
8.1.3.2.1 Anchor bolts shall be tested in
accordance with ASTM E488, except that a
minimum of five tests shall be performed. Loading 8.1.3.3.2 Allowable shear load of headed and bent-
conditions of the test shall be representative of bar anchor bolts — The allowable shear load, 𝐵𝑣,
intended use of the anchor bolt. of headed and bent-bar anchor bolts embedded
in
8.1.3.2.2 Anchor bolt allowable loads used for grout shall be the smallest of the values
design shall not exceed 20 percent of the average determined by Equation 8-6, Equation 8-7,
failure load from the tests. Equation 8-8, and
8.1.3.3 Allowable loads determined by calculation Equation 8-9.
for headed and bent-bar anchor bolts — Allowable
loads for headed and bent-bar anchor bolts 𝐵𝑣𝑏 = 0.104𝐴𝑝𝑣√𝑓′ Equation 8-6
�
embedded in grout shall be determined in 𝐵𝑣 = 10724√𝑓′ 𝐴 Equation 8-7
accordance with the provisions of Sections 𝑐
� �
8.1.3.3.1 through 8.1.3.3.3.
8.1.3.3.1 Allowable axial tensile load of headed 𝐵𝑣𝑝𝑟𝑦 = 2.0𝐵𝑎𝑏
Equation 8-8
and bent-bar anchor bolts — The allowable axial = 0.208𝐴𝑝𝑡√𝑓′
�
tensile load of headed anchor bolts shall be
calculated
using the provisions of Sections 8.1.3.3.1.1. The shall be
allowable axial tensile load of bent-bar anchor
bolts shall be calculated using the provisions of
Section 8.1.3.3.1.2.
8.1.3.3.1.1 Allowable axial tensile load of headed
anchor bolts —The allowable axial tensile load,
𝐵𝑎, of headed anchor bolts embedded in grout

SBC 305-CR- 3
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

𝐵𝑣𝑠 = 0.36𝐴𝑏𝑓𝑦 Equation 8-9 shear — Anchor bolts subjected to axial tension in
combination with shear shall satisfy Equation 8-10.
8.1.3.3.3 Combined axial tension and 𝑏𝑎 𝑏𝑣
+ ≤1 Equation 8-10
𝐵𝑎 𝐵𝑣

SBC 305-CR- 3
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

8.1.4 Shear stress in multiwythe masonry (c) 𝛾 = 1.5 for Dia 25 through Dia 36 bars.
elements
Development length of epoxy-coated bars shall be
8.1.4.1 Design of multiwythe masonry for taken as 150 percent of the length determined by
composite action shall meet the requirements of Equation 8-12.
Section 5.1.4.2 and Section 8.1.4.2.
8.1.6.4 Embedment of flexural reinforcement
8.1.4.2 Shear stresses developed at the interfaces
between wythes and collar joints or within headers 8.1.6.4.1 General
shall not exceed the following: 8.1.6.4.1.1 Tension reinforcement is permitted to
(a) Mortared collar joints, 48 kPa. be developed by bending across the neutral axis of
(b) Grouted collar joints, 89 kPa. the member to be anchored or made continuous
specified unit with reinforcement on the opposite face of the
(c) headers, 0.108√compressive strength, member.
of header 8.1.6.4.1.2 Critical sections for development of
MPa (over net area of header). reinforcement in flexural members are at points of
8.1.5 Bearing stress maximum steel stress and at points within the span
where adjacent reinforcement terminates or is
Bearing stresses on masonry shall not exceed bent.
0.33𝑓′ and shall be calculated over the bearing 8.1.6.4.1.3 Reinforcement shall extend beyond the
�
area, 𝐴𝑏𝑟, as defined in Section 4.3.4. point at which it is no longer required to resist
8.1.6 Development of reinforcement embedded flexure for a distance equal to the effective depth
in grout of the member or 12𝑑𝑏, whichever is greater,
except
8.1.6.1 General — The calculated tension or at supports of simple spans and at the free end of
compression in the reinforcement at each section cantilevers.
shall be developed on each side of the section by
development length, hook, mechanical device, or 8.1.6.4.1.4 Continuing reinforcement shall extend
combination thereof. Hooks shall not be used to a distance 𝑙𝑑 beyond the point where bent or
develop bars in compression. terminated tension reinforcement is no longer
required to resist flexure as required by Section
8.1.6.2 Development of wires in tension — The 8.1.6.2 or 8.1.6.3.
development length of wire shall be determined by
Equation 8-11 but shall not be less than 150 mm. 8.1.6.4.1.5 Flexural reinforcement shall not be
terminated in a tension zone unless one of the
following conditions is satisfied:
𝑙𝑑 = 0.22𝑑𝑏𝐹𝑠 Equation 8-11
(a) Shear at the cutoff point does not exceed
two-thirds of the allowable shear at the
Development length of epoxy-coated wire shall be
section considered.
taken as 150 percent of the length determined by
(b) Stirrup area in excess of that required for
Equation 8-11.
shear is provided along each terminated
8.1.6.3 Development of bars in tension or bar or wire over a distance from the
compression — The required development length termination point equal to three-fourths the
of reinforcing bars shall be determined by Equation effective depth of the member. Excess
8-12, but shall not be less than 300 mm. stirrup area, Av, shall not be less than
60bws/fy. Spacing s shall not exceed
1.57𝑑2𝑓𝑦𝛾
d/(8βb).
(c) Continuous reinforcement provides double
the area required for flexure at the cutoff
point and shear does not exceed three-
fourths the allowable shear at the section
𝑙𝑑 = 𝑏 Equation 8-12 considered.
′
𝐾√𝑓
� 8.1.6.4.1.6 Anchorage complying with Section
𝐾 shall not exceed the smallest of the following: (a) γ = 1.0 for Dia 10 through Dia 16 bars;
the minimum masonry cover, the clear spacing (b) 𝛾 = 1.3 for Dia 18 through Dia 22 bars;
between adjacent reinforcement splices, and 9𝑑𝑏.

SBC 305-CR- 3
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

8.1.6.2 or 8.1.6.3 shall be provided for

tension reinforcement in corbels, deep
flexural members, variable-depth
arches, members where flexural
reinforcement is not parallel with the
compression face, and in other cases
where the stress in flexural

SBC 305-CR- 3
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

reinforcement does not vary linearly through the member d/2, , and start of hook (point of
depth of the section. tangency).
8.1.6.4.2 Development of positive moment 8.1.6.6.1.3 Between the anchored ends, each bend
reinforcement — When a wall or other flexural in the continuous portion of a transverse U-stirrup
member is part of the lateral-force-resisting shall enclose a longitudinal bar.
system, at least 25 percent of the positive moment
reinforcement shall extend into the support and be 8.1.6.6.1.4 Longitudinal bars bent to act as shear
anchored to develop 𝐹𝑠 in tension. reinforcement, where extended into a region of
tension, shall be continuous with longitudinal
8.1.6.4.3 Development of negative moment reinforcement and, where extended into a region of
reinforcement compression, shall be developed beyond mid depth
8.1.6.4.3.1 Negative moment reinforcement in a of the member, 𝑑/2.
continuous, restrained, or cantilever member shall 8.1.6.6.1.5 Pairs of U-stirrups or ties placed to
be anchored in or through the supporting member form a closed unit shall be considered properly
in accordance with the provisions of Section spliced when length of laps are 1.7𝑙𝑑. In grout at
8.1.6.1.
least 450 mm deep, such splices with 𝐴𝑣𝑓𝑦 not
8.1.6.4.3.2 At least one-third of the total more than 40,000 N per leg shall be permitted to
reinforcement provided for moment at a support be considered adequate if legs extend the full
shall extend beyond the point of inflection the available depth of
greater distance of the effective depth of the grout.
member or one-sixteenth of the span.
8.1.6.6.2 Welded wire reinforcement
8.1.6.5 Hooks
8.1.6.6.2.1 For each leg of welded wire
8.1.6.5.1 Standard hooks in tension shall be reinforcement forming simple U-stirrups, there
considered to develop an equivalent embedment shall be either:
length, 𝑙𝑒, equal to 13𝑑𝑏.
(a) Two longitudinal wires at a 50 mm
8.1.6.5.2 The effect of hooks for bars in spacing along the member at the top of the
compression shall be neglected in design U, or
calculations. (b) One longitudinal wire located not more
than d/4 from the compression face and a
8.1.6.6 Development of shear reinforcement
second wire closer to the compression face
8.1.6.6.1 Bar and wire reinforcement and spaced at least 50 mm from the first
8.1.6.6.1.1 Shear reinforcement shall extend to a wire. The second wire shall be located on
distance 𝑑 from the extreme compression face and the stirrup leg beyond a bend, or on a bend
shall be carried as close to the compression and with an inside diameter of bend at least
tension surfaces of the member as cover 8db.
requirements and the proximity of other 8.1.6.6.2.2 For each end of a single-leg stirrup of
reinforcement permit. Shear reinforcement shall be plain or deformed welded wire reinforcement,
anchored at both ends for its calculated stress. there shall be two longitudinal wires spaced a
8.1.6.6.1.2 The ends of single-leg or U-stirrups minimum of 50 mm with the inner wire placed at a
shall be anchored by one of the following means: distance at least 𝑑/4 or 50 mm from middepth
of member,
(a) A standard hook plus an effective 𝑑/2. Outer longitudinal wire at tension face shall
embedment of 0.5ld. The effective not be farther from the face than the portion of
embedment of a stirrup leg shall be taken primary flexural reinforcement closest to the face.
as the distance between the mid-depth of
the 8.1.6.7 Splices of reinforcement — Lap splices,
member, d/2, and the start of the hook welded splices, or mechanical splices are
(point of tangency). permitted in accordance with the provisions of this
(b) For bar Dia 16 and MD200 wire and section.
smaller, bending around longitudinal 8.1.6.7.1 Lap splices — Lap splices shall not be
reinforcement through at least 135 degrees used in plastic hinge zones of special reinforced
plus an embedment of 0.33ld. The masonry shear walls. The length of the plastic
0.33ld embedment of a stirrup leg shall be hinge zone shall be taken as at least 0.15 times the
taken as the distance between middepth of distance between the point of zero moment and the

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

point of maximum moment.

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

8.1.6.7.1.1 The minimum length of lap for bars in wall system. Type 2 mechanical splices shall be
tension or compression shall be determined by permitted in any location within a member.
Equation 8-12, but not less than 300 mm.
8.1.6.7.4 End-bearing splices
8.1.6.7.1.2 Where reinforcement consisting of Dia
10 or larger bars is placed transversely within the 8.1.6.7.4.1 In bars required for compression only,
lap, with at least one bar 200 mm or less from each the transmission of compressive stress by bearing
end of the lap, the minimum length of lap for bars of square cut ends held in concentric contact by a
in tension or compression determined by Equation suitable device is permitted.
8-12 shall be permitted to be reduced by 8.1.6.7.4.2 Bar ends shall terminate in flat surfaces
multiplying
by the confinement factor, 𝜉, determined in within
1
1 degree of a right angle to the axis of the
accordance with Equation 8-13. The clear space
2
bars and shall be fitted within 3 degrees of full
between the transverse bars and the lapped bars bearing after assembly.
shall not exceed 38 mm and the transverse bars
shall be fully developed in grouted masonry. The 8.1.6.7.4.3 End-bearing splices shall be used only
reduced lap splice length shall not be less than in members containing closed ties, closed stirrups,
36𝑑𝑏. or spirals.

 = 1.0 − 11.60𝐴𝑠𝑐 Equation 8-13 8.1.6.7.5 Splicing of wires in tension

�𝑏2 8.1.6.7.5.1 Lap splices — The minimum length of
lap for wires in tension shall be determined by
where 11.60𝐴𝑠𝑐 ≤ 1.0 Equation 8-11, but shall not be less than 150 mm.
𝑏
𝑑
𝐴𝑠𝑐 is the area of the transverse bars at each end of 8.1.6.7.5.2 Welded splices — Welded splices shall
the lap splice and shall not be taken greater than have the wires welded to develop at least 125
226 mm2. percent of the specified yield strength of the wire
8.1.6.7.1.3 Bars spliced by noncontact lap splices in tension.
shall not be spaced transversely farther apart than 8.1.6.7.5.3 Mechanical splices — Mechanical
one-fifth the required length of lap nor more than splices shall have the wires connected to develop
200 mm. at least 125 percent of the specified yield strength
8.1.6.7.2 Welded splices — Welded splices shall of the wire in tension.
have the bars butted and welded to develop in
8.2 —Unreinforced masonry
tension at least 125 percent of the specified yield
strength of the bar. Welding shall conform to AWS 8.2.1 Scope
D1.4/D1.4M. Reinforcement to be welded shall
This section provides requirements for the design
conform to ASTM A706, or shall be accompanied
of unreinforced masonry as defined in Section 2.2.
by a submittal showing its chemical analysis and
Design of unreinforced masonry by the allowable
carbon equivalent as required by AWS
stress method shall comply with the requirements
D1.4/D1.4M. Existing reinforcement to be welded
of Part 1, Part 2, Section 8.1, and Section 8.2.
shall conform to ASTM A706, or shall be analyzed
chemically and its carbon equivalent determined as 8.2.2 Design criteria
required by AWS D1.4/D1.4M. Welded splices
Unreinforced masonry members shall be designed
shall not be permitted in plastic hinge zones of
in accordance with the principles of engineering
intermediate or special reinforced walls of masonry.
mechanics and shall be designed to remain
8.1.6.7.3 Mechanical splices — Mechanical uncracked.
splices shall have the bars connected to develop in
tension or compression, as required, at least 125 8.2.3 Design assumptions
percent of the specified yield strength of the bar. The following assumptions shall be used in the
Mechanical splices shall be classified as Type 1 or design of unreinforced masonry members:
Type 2 according to Section 21.1.6.1 of SBC 304.
(a) Strain in masonry is directly proportional
Type 1 mechanical splices shall not be used within
to the distance from the neutral axis.
a plastic hinge zone or within a beam-wall joint of
(b) Flexural tensile stress in masonry is
intermediate or special reinforced masonry shear
directly proportional to strain.

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

(c) Flexural compressive stress in Axial tension resistance of unreinforced masonry

combination with axial compressive stress shall be neglected in design.
in masonry is directly proportional to
strain. 8.2.6 Shear
(d) Stresses in reinforcement, if present, are 8.2.6.1 Shear stresses due to forces acting in the
neglected when determining the resistance direction considered shall be calculated in
of masonry to design loads. accordance with Section 4.3.1 and determined by
8.2.4 Axial compression and flexure Equation 8-20.

8.2.4.1 Axial and flexural compression —

Members subjected to axial compression, flexure, 𝑉𝑄
𝑓 = Equation 8-20
or to combined axial compression and flexure shall 𝐼𝑛𝑏
𝑣
be designed to satisfy Equation 8-14 and Equation
8-15. 8.2.6.2 In-plane shear stresses shall not exceed any
of:
𝑓
𝑎 +
𝑓𝑏 ≤1 Equation 8-14 (a) 0.125√f ′
m
𝐹 𝐹 (b) 0.827 MPa
𝑎 𝑏
1 (c) For running bond masonry not fully
Equation 8-15 grouted;
𝑃≤( )
𝑃𝑒 4 0.255 + 0.45𝑁𝑣/𝐴𝑛
where:
(d) For masonry not laid in running bond,
(a) For members having an ℎ/𝑟 ratio not constructed of open end units, and fully
greater than 99: grouted;
1 ′
0.255 + 0.45𝑁𝑣/𝐴𝑛
𝐹𝑎 = ( ) 𝑓 𝑚 ×
4 2 Equation 8-16 (e) For running bond masonry fully grouted;
ℎ
[1 − ( ) ] 0.414 + 0.45𝑁𝑣/𝐴𝑛
140𝑟
(f) For masonry not laid in running bond,
(b) For members having an h/r ratio greater constructed of other than open end units,
than 99: and fully grouted;
1 2
𝐹𝑎 = ( ) 𝑓′ 70𝑟 ) Equation 8-17 103kPa
4 ℎ
( 8.2.6.3 The minimum normalized web area of
(c) �
concrete masonry units, determined in accordance
with ASTM C140, shall not be less than
1
) 𝑓′ Equation 8-18 187,500 mm2/m2 or the calculated shear stresses
𝐹𝑏 = ( �
3 in the webs shall not exceed the value given in
(d) Section 8.2.6.2(a).
𝜋2𝐸𝑚𝐼𝑛 8.3 —Reinforced masonry
𝑃𝑒 =
ℎ2 Equation 8-19 8.3.1 Scope
𝑒 3 8.2.5 Axial tension
× (1 − 0.577 )
𝑟
8.2.4.2 Flexural tension — Allowable tensile
stresses for masonry elements subjected to out-of-
plane or in-plane bending shall be in accordance
with the values in Table 8.1. For grouted masonry
not laid in running bond, tension parallel to the bed
joints shall be assumed to be resisted only by the
minimum cross-sectional area of continuous grout
that is parallel to the bed joints.

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

This section provides requirements for

the design of structures in which
reinforcement is used to resist tensile
forces in accordance with the
principles of engineering mechanics
and the contribution of the tensile
strength of masonry is neglected,
except as provided in Section 8.3.5.
Design of reinforced masonry by the
allowable stress method shall comply
with the requirements of Part 1, Part 2,
Section 8.1, and Section 8.3.
8.3.2 Design assumptions

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

The following assumptions shall be used in the

design of reinforced masonry: 𝑃𝑎 = (0.25𝑓′ 𝐴𝑛
�
(a) Strain compatibility exists between the Equation 8-22
70𝑟 2

reinforcement, grout, and masonry. +0.65𝐴𝑠𝑡𝐹𝑠) ( )

(b) Strains in reinforcement and masonry are ℎ
directly proportional to the distances from 8.3.4.2.2 The compressive stress in masonry due to
the neutral axis. flexure or due to flexure in combination with axial
(c) Stress is linearly proportional to the strain. load shall not exceed 0.45𝑓′ provided that the
(d) The compressive resistance of steel �
calculated compressive stress due to the axial load
reinforcement does not contribute to the component, 𝑓𝑎, does not exceed the allowable
axial and flexural strengths unless lateral stress, 𝐹𝑎, in Section 8.2.4.1.
reinforcement is provided in compliance
with the requirements of Section 5.3.1.4. 8.3.4.3 Columns — Design axial loads shall be
(e) Stresses remain in the elastic range. assumed to act at an eccentricity at least equal to
(f) Masonry in tension does not contribute to 0.1 multiplied by each side dimension. Each axis
axial and flexural resistances. Axial and shall be considered independently.
flexural tension stresses are resisted 8.3.4.4 Walls — Special reinforced masonry shear
entirely by steel reinforcement. walls having a shear span ratio, 𝑀/(𝑉𝑑𝑣), equal to
8.3.3 Steel reinforcement — Allowable stresses or greater than 1.0 and having an axial load, 𝑃,
greater than 0.05𝑓′ 𝐴𝑛, which are subjected to in-
8.3.3.1 Tensile stress in bar reinforcement shall plane forces, shall� have a maximum ratio of
not exceed the following: flexural tensile reinforcement, 𝜌𝑚𝑎𝑥 not greater
(a) Grade 40 or Grade 50 reinforcement: 138 than that calculated as follows:
MPa 𝑛𝑓′
(b) Grade 60 reinforcement: 220 MPa 𝜌𝑚𝑎𝑥 𝑚
= 𝑓𝑦 Equation 8-23
8.3.3.2 Tensile stress in wire joint reinforcement 2𝑓 (𝑛 + )
𝑦 𝑚
shall not exceed 205 MPa.
8.3.3.3 When lateral reinforcement is provided in The maximum reinforcement ratio does not apply
compliance with the requirements of Section in the out-of-plane direction.
5.3.1.4, the compressive stress in bar reinforcement
8.3.5 Shear
shall not exceed the values given in Section 8.3.3.1.
8.3.5.1 Members shall be designed in accordance
8.3.4 Axial compression and flexure with Sections 8.3.5.1.1 through 8.3.5.1.4.
8.3.4.1 Members subjected to axial compression,
8.3.5.1.1 Calculated shear stress in the masonry
flexure, or combined axial compression and
shall be determined by the relationship:
flexure shall be designed in compliance with
Sections
8.3.4.2 through 8.3.4.4. 𝑉
𝑓 = Equation 8-24
𝐴𝑛𝑣
8.3.4.2 Allowable forces and stresses 𝑣

8.3.4.2.1 The compressive force in reinforced

8.3.5.1.2 The calculated shear stress, 𝑓𝑣, shall not
masonry due to axial load only shall not exceed
exceed the allowable shear stress, 𝐹𝑣, where 𝐹𝑣
that given by Equation 8-21 or Equation 8-22:
shall be calculated using Equation 8-25 and shall not
(a) For members having an h/r ratio not be taken greater than the limits given by Section
greater than 99: 8.3.5.1.2(a) through (c).

𝑃𝑎 = (0.25𝑓′ 𝐴𝑛
� 𝐹𝑣 = + )𝛾𝑔 Equation 8-25
2
ℎ Equation 8-21 (𝐹𝑣𝑚 𝐹𝑣𝑠
+0.65𝐴𝑠𝑡𝐹𝑠) [1 − ( ) ] (a) Where M/(Vdv) ≤ 0.25:
140𝑟
(b) For members having an h/r ratio greater 𝐹𝑣 ≤ (0.249√𝑓′ ) 𝛾 Equation 8-26
𝑚 𝑔
than 99:
(b) Where M/(Vdv) ≥ 1.0:

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

8.3.5.2 Shear reinforcement shall be provided when

𝐹𝑣 ≤ (0.167√𝑓′ ) 𝛾 Equation 8-27 𝑓𝑣 exceeds 𝐹𝑣𝑚. When shear reinforcement is
𝑚 𝑔
required, the provisions of Section 8.3.5.2.1 and
𝛾𝑔 = 0.75 for partially grouted shear walls and 1.0 8.3.5.2.2 shall apply.
otherwise. 8.3.5.2.1 Shear reinforcement shall be provided
parallel to the direction of applied shear force.
(c) The maximum value of Fv for M/(Vdv)
between 0.25 and 1.0 shall be permitted to Spacing of shear reinforcement shall not exceed
be linearly interpolated. the lesser of 𝑑/2 or 1200 mm.

8.3.5.1.3 The allowable shear stress resisted by the 8.3.5.2.2 Reinforcement shall be provided
masonry, 𝐹𝑣𝑚 shall be calculated using Equation perpendicular to the shear reinforcement and shall
8-28 for special reinforced masonry shear walls be at least equal to one-third. The reinforcement
and using Equation 8-29 for other masonry: shall be uniformly distributed and shall not exceed
a spacing of 2.44 m.
𝑃 8.3.5.3 In composite masonry walls, shear stresses
𝐹𝑣 = 0.25 + 0.021 ×
𝐴𝑛 developed in the planes of interfaces between
𝑚
Equation 8-28 wythes and filled collar joints or between wythes
𝑀 and headers shall meet the requirements of Section
[(4.0 − 1.75 ( )) 𝑓𝑚]
𝑉𝑑𝑣 √ 8.1.4.2.
8.3.5.4 In cantilever beams, the maximum shear
𝐹𝑣 = 0.25 𝑃 shall be used. In non-cantilever beams, the
+ 0.042 ×
𝑚 𝐴𝑛 maximum shear shall be used except that sections
Equation 8-29 located within a distance 𝑑/2 from the face of
𝑀
[(4.0 − 1.75 ( )) 𝑓𝑚 ] support shall be designed for the same shear as
𝑉𝑑𝑣 √ that calculated at a distance 𝑑/2 from the face of
support when the following conditions are met:
𝑀/(𝑉𝑑𝑣) shall be taken as a positive number and
need not be taken greater than 1.0. (a) Support reaction, in direction of applied
shear force, introduces compression into
8.3.5.1.4 The allowable shear stress resisted by the the end regions of the beam, and
steel reinforcement, 𝐹𝑣𝑠 shall be calculated using (b) No concentrated load occurs between face
Equation 8-30: of support and a distance 𝑑/2 from face.
𝐴𝑣𝐹𝑠𝑑𝑣
𝐹𝑣𝑠 = 0.5 ( ) Equation 8-30
𝐴𝑛𝑣𝑆

SBC 305-CR- 4
 CHAPTER 8—ALLOWABLE STRESS DESIGN OF

TABLES OF CHAPTER 8

Table 8.1: Allowable flexural tensile stresses for clay and concrete masonry, kPa

Mortar types
Direction of flexural tensile
stress and masonry type Portland cement/lime or Masonry cement or air entrained
mortar cement Portland cement/lime
M or S N M or S N
Normal to bed joints
Solid units 366 276 221 138
Hollow units1
Ungrouted 228 172 138 83
Fully grouted 448 434 420 400
Parallel to bed joints in running
bond
Solid units 731 552 441 276
Hollow units
Ungrouted and partially 455 345 276 172
grouted
Fully grouted 731 552 441 276
Parallel to bed joints in masonry
not laid in running bond
Continuous grout section 917 917 917 917
parallel to bed joints
Other 0 0 0 0
1
For partially grouted masonry, allowable stresses shall be determined on the basis of linear interpolation between fully
grouted hollow units and ungrouted hollow units based on amount (percentage) of grouting.

SBC 305-CR- 4
 CHAPTER 9—STRENGTH DESIGN OF

CHAPTER 9—STRENGTH DESIGN OF MASONRY

9.1.4.5 Shear — The value of 𝜙 shall be taken as

9.1 —General
0.80 for masonry subjected to shear.
9.1.1 Scope
9.1.5 Deformation requirements
This Chapter provides minimum requirements for
9.1.5.1 Deflection of unreinforced (plain) masonry
strength design of masonry. Masonry design by the
— Deflection calculations for unreinforced (plain)
strength design method shall comply with the
masonry members shall be based on uncracked
requirements of Part 1, Part 2, Sections 9.1.2
section properties.
through 9.1.9, and either Section 9.2 or 9.3.
9.1.5.2 Deflection of reinforced masonry -
9.1.2 Required strength Deflection calculations for reinforced masonry
Required strength shall be determined in members shall consider the effects of cracking and
accordance with the strength design load reinforcement on member stiffness. The flexural
combinations of SBC 301. Members subject to and shear stiffness properties assumed for
compressive axial load shall be designed for the deflection calculations shall not exceed one-half of
factored moment accompanying the factored axial the gross section properties, unless a cracked-
load. The factored moment, 𝑀𝑢, shall include the section analysis is performed.
moment induced by relative lateral displacement
9.1.6 Anchor bolts embedded in grout
9.1.3 Design strength Anchorage assemblies connecting masonry
Masonry members shall be proportioned so that elements that are part of the seismic force-resisting
the design strength equals or exceeds the required system to diaphragms and chords shall be designed
strength. Design strength is the nominal strength so that the strength of the anchor is governed by
multiplied by the strength-reduction factor, 𝜙, as steel tensile or shear yielding. Alternatively, the
specified in Section 9.1.4. anchorage assembly is permitted to be designed so
that it is governed by masonry breakout or anchor
9.1.4 Strength-reduction factors pullout provided that the anchorage assembly is
9.1.4.1 Anchor bolts — For cases where the designed to resist not less than 2 times the factored
nominal strength of an anchor bolt is controlled by forces transmitted by the assembly.
masonry breakout, by masonry crushing, or by 9.1.6.1 Design requirements — Anchor bolts shall
anchor bolt pryout, 𝜙 shall be taken as 0.50. For be designed using either the provisions of 9.1.6.2
cases where the nominal strength of an anchor bolt or, for headed and bent-bar anchor bolts, by the
is controlled by anchor bolt steel, 𝜙 shall be taken provisions of Section 9.1.6.3.
as 0.90. For cases where the nominal strength of
an anchor bolt is controlled by anchor pullout, 𝜙 9.1.6.2 Nominal strengths determined by test
shall be taken as 0.65. 9.1.6.2.1 Anchor bolts shall be tested in
9.1.4.2 Bearing — For cases involving bearing on accordance with ASTM E488, except that a
masonry, 𝜙 shall be taken as 0.60. minimum of five tests shall be performed. Loading
conditions of the test shall be representative of
9.1.4.3 Combinations of flexure and axial load in intended use of the anchor bolt.
unreinforced masonry — The value of 𝜙 shall be
taken as 0.60 for unreinforced masonry subjected 9.1.6.2.2 Anchor bolt nominal strengths used for
to flexure, axial load, or combinations thereof. design shall not exceed 65 percent of the average
failure load from the tests.
9.1.4.4 Combinations of flexure and axial load in
reinforced masonry — The value of 𝜙 shall be 9.1.6.3 Nominal strengths determined by
taken as 0.90 for reinforced masonry subjected to calculation for headed and bent-bar anchor bolts
flexure, axial load, or combinations thereof — Nominal strengths of headed and bent-bar
anchor bolts embedded in grout shall be
determined in

SBC 305-CR- 4
 CHAPTER 9—STRENGTH DESIGN OF

accordance with the provisions of Sections 9.1.6.3.1 (nominal shear strength governed by steel
through 9.1.6.3.3. yielding). The design shear strength 𝜙𝐵𝑣𝑛 shall be
9.1.6.3.1 Nominal tensile strength of headed and the smallest of the values obtained from Equation 9-
bent-bar anchor bolts — The nominal axial tensile 6, Equation 9-7, Equation 9-8 and Equation
strength of headed anchor bolts shall be calculated 9-9
using the provisions of Sections 9.1.6.3.1.1. The multiplied by the applicable 𝜙 value.
nominal axial tensile strength of bent-bar anchor
bolts shall be calculated using the provisions of 𝐵𝑣𝑛𝑏 = 0.332𝐴𝑝𝑡√𝑓′ Equation 9-6
�
� �

SBC 305-CR- 4
 CHAPTER 9—STRENGTH DESIGN OF

Section 9.1.6.3.1.2. 𝐵𝑣𝑛 = 32164√𝑓′ 𝐴 Equation 9-7

9.1.6.3.1.1 Axial tensile strength of headed anchor 𝑐

bolts — The nominal axial tensile strength, Ban of 𝐵𝑣𝑛𝑝𝑟𝑦 = 2.0𝐵𝑎𝑛𝑏

headed anchor bolts embedded in grout shall be Equation 9-8
= 0.664𝐴𝑝𝑡√𝑓′
determined by Equation 9-1 (nominal axial tensile �
strength governed by masonry breakout) or 𝐵𝑣𝑛𝑠 = 0.6𝐴𝑏𝑓𝑦 Equation 9-9
Equation 9-2 (nominal axial tensile strength
governed by steel yielding). The design axial 9.1.6.3.3 Combined axial tension and shear —
tensile strength, 𝜙𝐵𝑎𝑛 shall be the smaller of the Anchor bolts subjected to axial tension in
values combination with shear shall satisfy Equation 9-10.
obtained from Equation 9-1 and Equation 9-2
𝑏𝑎𝑓 𝑏𝑣𝑓
multiplied by the applicable 𝜙 value. + ≤1 Equation 9-10
∅𝐵𝑎𝑛 ∅𝐵𝑣𝑛
𝐵𝑎𝑛𝑏 = 0.332𝐴𝑝𝑡√𝑓′ Equation 9-1
�
9.1.7 Shear strength in multiwythe masonry
𝐵𝑎𝑛𝑠 = 𝐴𝑏𝑓𝑦 Equation 9-2 elements
9.1.7.1 Design of multiwythe masonry for
9.1.6.3.1.2 Axial tensile strength of bent-bar composite action shall meet the requirements of
anchor bolts – The nominal axial tensile strength, Sections 5.1.4.2 and 9.1.7.2.
𝐵𝑎𝑛, for bent-bar anchor bolts embedded in grout
shall be 9.1.7.2 The nominal shear strength at the
determined by Equation 9-3 (nominal axial tensile interfaces between wythes and collar joints or
strength governed by masonry breakout), Equation within headers shall be determined so that shear
9-4 (nominal axial tensile strength governed by stresses shall not exceed the following:
anchor bolt pullout), or Equation 9-5 (nominal axial (a) Mortared collar joints, 96 kPa.
tensile strength governed by steel yielding). The (b) Grouted collar joints, 179 kPa.
design axial tensile strength, 𝜙𝐵𝑎𝑛, shall be the
specified unit
smallest of the values obtained from Equation 9-3,
(c) headers, 0.108√compressive strength,
Equation 9-4 and Equation 9-5 multiplied by the
of header
applicable 𝜙 value. MPa (over net area of header).

𝐵𝑎𝑛𝑏 = 0.332𝐴𝑝𝑡√𝑓′ Equation 9-3 9.1.8 Nominal bearing strength

�
𝐵𝑎𝑛𝑝 = 1.5𝑓′ 𝑒 𝑑
𝑚 𝑏 𝑏
Equation 9-4 The nominal bearing strength of masonry shall be
+2.07𝜋(𝑙𝑏 + 𝑒𝑏 + 𝑑𝑏)𝑑𝑏 calculated as 0.8𝑓′ multiplied by the bearing area,
�
𝐴𝑏𝑟, as defined in Section 4.3.4.
𝐵𝑎𝑛𝑠 = 𝐴𝑏𝑓𝑦 Equation 9-5
9.1.9 Material properties
9.1.6.3.2 Shear strength of headed and bent-bar
9.1.9.1 Compressive strength
anchor bolts — The nominal shear strength, 𝐵𝑣𝑛,
of headed and bent-bar anchor bolts shall 9.1.9.1.1 Masonry compressive strength — The
be specified compressive strength of masonry, 𝑓′
�
determined by Equation 9-6 (nominal shear strength shall equal or exceed 10 MPa. The value of 𝑓′
�
governed by masonry breakout), Equation 9-7 used to determine nominal strength values in this
(nominal shear strength governed by masonry chapter shall not exceed 27 MPa for concrete
crushing), Equation 9-8 (nominal shear strength masonry and shall not exceed 41 MPa for clay
governed by anchor bolt pryout) or Equation 9-9 masonry.

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

9.1.9.1.2 Grout compressive strength — For (b) Flexural tension in masonry shall be
concrete masonry, the specified compressive assumed to be directly proportional to
strength of grout, 𝑓′ shall equal or exceed the strain.
specified compressive� strength of masonry, 𝑓′
(c) Flexural compressive stress in
but shall not exceed 35 MPa. For clay masonry,
�
combination with axial compressive stress
the specified compressive strength of grout, 𝑓′, in masonry shall be assumed to be directly
shall not exceed 41 MPa. � proportional to strain.
9.1.9.2 Masonry modulus of rupture — The (d) Stresses in the reinforcement are not
modulus of rupture, 𝑓𝑟, for masonry elements accounted for in determining the resistance
subjected to out-of-plane or in-plane bending shall to design loads
be in accordance with the values in Table 9.1. For 9.2.4 Nominal flexural and axial strength
grouted masonry not laid in running bond, tension
parallel to the bed joints shall be assumed to be 9.2.4.1 Nominal strength — The nominal strength
resisted only by the minimum cross-sectional area of unreinforced (plain) masonry cross-sections for
of continuous grout that is parallel to the bed combined flexure and axial loads shall be
joints. determined so that:

9.1.9.3 Reinforcement strengths (a) The compressive stress does not exceed
0.80f ′ .
9.1.9.3.1 Reinforcement for in-plane flexural m
(b) The tensile stress does not exceed the
tension and flexural tension perpendicular to bed modulus of rupture determined from
joints — Masonry design shall be based on a Section 9.1.9.2.
reinforcement strength equal to the specified yield
strength of reinforcement, 𝑓𝑦, which shall not 9.2.4.2 Nominal axial strength — The nominal
exceed 414 MPa. The actual yield strength shall axial strength, 𝑃𝑛, shall not be taken greater than
not exceed 1.3 multiplied by the specified yield the following:
strength. (a) For members having an ℎ/𝑟 ratio not
9.1.9.3.2 Reinforcement for in-plane shear and greater than 99:
flexural tension parallel to bed joints — Masonry 𝐴 𝑓′
𝑛 𝑚
design shall be based on a specified yield strength, 𝑃 = 0.80 { ×
𝑓𝑦, which shall not exceed 414 MPa for reinforcing 𝑛
1.25 Equation 9-11
bars and which shall not exceed 586 MPa for 2
reinforcing wire. [1 − ℎ ) ]}
( 140𝑟
9.2 —Unreinforced (plain) masonry

9.2.1 Scope (b) For members having an h/r ratio greater

than 99:
Design of unreinforced masonry by the strength
design method shall comply with the requirements 𝑃𝑛 = 0.80 ×
2
of Part 1, Part 2, Section 9.1, and Section 9.2. [0.80𝐴 𝑓 ( 70𝑟) ] Equation 9-12
′
9.2.2 𝑛 𝑚
ℎ
Design criteria
Unreinforced masonry members shall be designed
9.2.4.3 P-Delta effects
in accordance with the principles of engineering
mechanics and shall be designed to remain 9.2.4.3.1 Members shall be designed for the
uncracked. factored axial load, 𝑃𝑢, and the moment magnified
for the effects of member curvature, 𝑀𝑢.
9.2.3 Design assumptions
9.2.4.3.2 The magnified moment, 𝑀𝑢, shall be
The following assumptions shall be used in the
determined either by a second-order analysis, or by
design of unreinforced masonry members: a first-order analysis and Equation 9-13 and
(a) Strain in masonry shall be directly Equation 9-14.
proportional to the distance from the
neutral axis. 𝑀𝑢 = 𝜓𝑀𝑢, 0 Equation 9-13

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

1 shall comply with the requirements of Part 1, Part

𝜓= 𝑃𝑢 Equation 9-14 2, Section 9.19.1, and Section 9.3.
1− 70𝑟 2
′ 9.3.2 Design assumptions
� 𝑓 ℎ )
𝑛 𝑚
The following assumptions shall be used in the
9.2.4.3.3 A value of 𝜓 = 1 shall be permitted for design of reinforced masonry:
members in which ℎ/ 𝑟 ≤ 45. (a) Strain compatibility exists between the
9.2.4.3.4 A value of 𝜓 = 1 shall be permitted for reinforcement, grout, and masonry.
members in which 45 < ℎ / 𝑟 ≤ 60, provided that (b) The nominal strength of reinforced
the nominal strength defined in Section 9.2.4.1 is masonry cross-sections for combined
reduced by 10 percent. flexure and axial load is based on
applicable conditions of equilibrium.
9.2.5 Axial tension — axial tension resistance of
(c) The maximum usable strain, εmu, at the
unreinforced masonry shall be neglected in design.
extreme masonry compression fiber is
9.2.6 Nominal shear strength 0.0035 for clay masonry and 0.0025 for
concrete masonry.
9.2.6.1 Nominal shear strength, 𝑉𝑛, shall be the (d) Strains in reinforcement and masonry are
smallest of (a), (b) and the applicable condition of directly proportional to the distance from
(c) through (f): the neutral axis.
(a) 0.316Anv√f ′ (e) Compression and tension stress in
(b) 2.07 Anv m reinforcement is Es multiplied by the steel
(c) For running bond masonry not fully strain, but not greater than fy. Except as
grouted; permitted in Section 9.3.3.5.1 (e) for
determination of maximum area of
0.386𝐴𝑛𝑣 + 0.45𝑁𝑢
flexural reinforcement, the compressive
(d) For masonry not laid in running bond, stress of steel reinforcement does not
constructed of open end units, and fully contribute to the axial and flexural
grouted; resistance unless lateral restraining
reinforcement is provided in compliance
0.386𝐴𝑛𝑣 + 0.45𝑁𝑢
with the requirements of Section 5.3.1.4.
(e) For running bond masonry fully grouted; (f) Masonry in tension does not contribute to
0.620𝐴𝑛𝑣 + 0.45𝑁𝑢 axial and flexural strengths. Axial and
flexural tension stresses are resisted
(f) For masonry not laid in running bond, entirely by steel reinforcement.
constructed of other than open end units, (g) The relationship between masonry
and fully grouted; compressive stress and masonry strain is
0.159𝐴𝑛𝑣 defined by the following:

9.2.6.2 The minimum normalized web area of Masonry stress of 0.80𝑓′ is uniformly distributed
�
concrete masonry units, determined in accordance over an equivalent compression stress block
with ASTM C140, shall not be less than bounded by edges of the cross section and a
187,500 mm2/m2 or the nominal shear strength of straight line located parallel to the neutral axis and
located at a distance 𝑎 = 0.80𝑐 from the fiber of
maximum
the web shall not exceed 0.316𝐴𝑛𝑣√𝑓′ 𝐼 𝑏/𝑄 compressive strain. The distance 𝑐 from the fiber
𝑚
of maximum strain to the neutral axis shall be
9.3 —Reinforced masonry
measured perpendicular to the neutral axis.
9.3.1 Scope
9.3.3 Reinforcement requirements and details
This section provides requirements for the design
9.3.3.1 Reinforcement size limitations
of structures in which reinforcement is used to
resist tensile forces in accordance with the (a) Reinforcing bars used in masonry shall not
principles of engineering mechanics and the be larger than Dia 28. The nominal bar
contribution of the tensile resistance of the diameter shall not exceed one-eighth of
masonry is neglected except as provided in Section the nominal member thickness and shall
9.3.4.1.2. Design of reinforced masonry by the not exceed one-quarter of the least
strength design method clear

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

dimension of the cell, course, or collar the distance between the mid-depth of the
joint in which the bar is placed. The area member, d/2, and the start of the hook
of reinforcing bars placed in a cell or in a (point of tangency).
course of hollow unit construction shall (b) For Dia 16 bars and smaller, bending
not exceed 4 percent of the cell area around longitudinal reinforcement through
(b) Joint reinforcement longitudinal wire used at least 135 degrees plus an embedment of
in masonry as shear reinforcement shall be ld/3. The ld/3 embedment of a stirrup leg
at least 5 mm diameter. shall be taken as the distance between mid-
9.3.3.2 Standard hooks — Standard hooks in depth of the member, d/2, and the start of
tension shall be considered to develop an the hook (point of tangency).
equivalent embedment length, le, as determined by (c) Between the anchored ends, each bend in
Equation 9-15: the continuous portion of a transverse U-
stirrup shall enclose a longitudinal bar.
𝑙𝑒 = 13𝑑𝑏 Equation 9-15 9.3.3.3.2.2 At wall intersections, horizontal
reinforcing bars needed to satisfy shear strength
9.3.3.3 Development — The required tension or
requirements of Section 9.3.4.1.2 shall be bent
compression reinforcement shall be developed in
around the edge vertical reinforcing bar with a 90-
accordance with the following provisions:
degree standard hook and shall extend horizontally
The required development length of reinforcement into the intersecting wall a minimum distance at
shall be determined by Equation 9-16, but shall not least equal to the development length.
be less than 300 mm. 9.3.3.3.2.3 Joint reinforcement used as shear
2
1.57𝑑 𝑓𝑦𝛾 reinforcement and needed to satisfy the shear
𝑏 strength requirements of Section 9.3.4.1.2 shall be
𝑙𝑑 = Equation 9-16 anchored around the edge reinforcing bar in the
𝑘√𝑓′
� edge cell, either by bar placement between adjacent
𝐾 shall not exceed the smallest of the following: cross-wires or with a 90-degree bend in
the minimum masonry cover, the clear spacing longitudinal wires bent around the edge cell and
between adjacent reinforcement splices, and 9𝑑𝑏. with at least 75- mm bend extensions in mortar or
grout.
(a) γ = 1.0 for Dia 10 through Dia 16 bars;
(b) 𝛾 = 1.3 for Dia 18 through Dia 22 bars; 9.3.3.3.3 Development of wires in tension — the
(c) 𝛾 = 1.5 for Dia 25 through Dia 28 bars. development length of wire shall be determined by
Equation 9-17, but shall not be less than 150 mm.
Development length of epoxy-coated reinforcing
bars shall be taken as 150 percent of the length
𝑙𝑑 = 48𝑑𝑏 Equation 9-17
determined by Equation 9-16.
9.3.3.3.1 Reinforcement spliced by noncontact lap Development length of epoxy-coated wire shall be
splices shall not be spaced farther apart than one- taken as 150 percent of the length determined by
fifth the required length of lap nor more than 200 Equation 9-17.
mm.
9.3.3.4 Splices — Reinforcement splices shall
9.3.3.3.2 Shear reinforcement shall extend the comply with one of the following:
depth of the member less cover distances.
(a) The minimum length of lap for bars shall be
9.3.3.3.2.1 Except at wall intersections, the end of 300 mm or the development length
a horizontal reinforcing bar needed to satisfy shear determined by Equation 9-16, whichever is
strength requirements of Section 9.3.4.1.2 shall be greater.
bent around the edge vertical reinforcing bar with (b) Where reinforcement consisting of M10 or
a 180-degree hook. The ends of single-leg or U- larger bars is placed within the lap, with at
stirrups shall be anchored by one of the following least one bar 200 mm or less from each
means: end of the lap, the minimum length of lap
for bars in tension or compression
(a) A standard hook plus an effective
embedment of ld/2. The effective determined by Equation 9-16 shall be
permitted to be reduced by multiplying the
embedment of a stirrup leg shall be taken
as confinement reinforcement factor, ξ. The
clear space between the transverse bars
and the lapped

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

bars shall not exceed 38 mm and the maximum strain in the masonry as given by
transverse bars shall be fully developed in Section 9.3.2(c).
grouted masonry. The reduced lap splice (b) The design assumptions of Section 9.3.2
length shall not be less than 36db. shall apply.
11.60𝐴𝑠𝑐 (c) The stress in the tension reinforcement
ξ = 1.0 − 2.5 Equation 9-18 shall be taken as the product of the modulus
�𝑏 of elasticity of the steel and the strain in the
reinforcement, and need not be taken
Where: 11.60𝐴𝑠𝑐
𝑏
≤ 1.0 greater than fy.
𝑑
𝐴𝑠𝑐 is the area of the transverse bars at each end of (d) Axial forces shall be taken from the
the lap splice and shall not be taken greater than loading combination given by D + 0.75L
226 mm2. + 0.525QE.
(c) A welded splice shall be capable of (e) The effect of compression reinforcement,
developing in tension at least 125 percent with or without lateral restraining
of the specified yield strength, fy, of the reinforcement, shall be permitted to be
included for purposes of calculating
bar. Welded splices shall only be
maximum flexural tensile reinforcement.
permitted for ASTM A706 steel
reinforcement. Welded splices shall not be 9.3.3.5.2 For intermediate Reinforced masonry
permitted in plastic hinge zones of shear walls subject to in-plane loads where
intermediate or special reinforced walls of 𝑀𝑢/(𝑉𝑢𝑑𝑣) ≥ 1, a strain gradient corresponding to
masonry. a strain in the extreme tensile reinforcement equal
(d) Mechanical splices shall be classified as to 3 multiplied by the yield strain and a maximum
Type 1 or Type 2 according to Section strain in the masonry as given by Section 9.3.2(c)
21.1.6.1 of SBC 304. Type 1 mechanical shall be used. For intermediate reinforced masonry
splices shall not be used within a plastic shear walls subject to out-of-plane loads, the
hinge zone or within a beam-column joint provisions of Section 9.3.3.5.1 shall apply.
of intermediate or special reinforced 9.3.3.5.3 For special reinforced masonry shear
masonry shear walls. Type 2 mechanical walls subject to in-plane loads where 𝑀𝑢/(𝑉𝑢𝑑𝑣)
splices are permitted in any location ≥ 1, a strain gradient corresponding to a strain in
within a member. the extreme tensile reinforcement equal to 4
(e) Where joint reinforcement is used as multiplied
shear reinforcement, the splice length of by the yield strain and a maximum strain in the
the longitudinal wires shall be a minimum masonry as given by Section 9.3.2(c) shall be used.
of 48db. For special reinforced masonry shear walls subject
9.3.3.4.1 Lap splices shall not be used in plastic to out-of-plane loads, the provisions of Section
hinge zones of special reinforced masonry shear 9.3.3.5.1 shall apply.
walls. The length of the plastic hinge zone shall be
9.3.3.5.4 For masonry members where 𝑀𝑢/
taken as at least 0.15 times the distance between (𝑉𝑢𝑑𝑣) ≤ 1 and when designed using 𝑅 ≤ 1.5,
the point of zero moment and the point of there is no upper limit to the maximum flexural
maximum moment. tensile reinforcement. For masonry members where
9.3.3.5 Maximum area of flexural tensile 𝑀𝑢/(𝑉𝑢𝑑𝑣) ≤ 1 and when designed using 𝑅 ≥
reinforcement 1.5, the provisions of Section 9.3.3.5.1 shall apply.
9.3.3.5.1 For masonry members where 𝑀𝑢/ 9.3.3.6 Bundling of reinforcing bars —
(𝑉𝑢𝑑𝑣) ≥ 1, the cross-sectional area of flexural Reinforcing bars shall not be bundled.
tensile reinforcement shall not exceed the area 9.3.3.7 Joint reinforcement used as shear
required to maintain axial equilibrium under the reinforcement — Joint reinforcement used as shear
following conditions: reinforcement shall consist of at least two 5 mm
(a) A strain gradient shall be assumed, diameter longitudinal wires located within a bed
corresponding to a strain in the extreme joint and placed over the masonry unit face shells.
tensile reinforcement equal to 1.5 The maximum spacing of joint reinforcement used
multiplied by the yield strain and a as shear reinforcement shall not exceed 400 mm
for Seismic Design Categories (SDC) A and B and
shall not exceed 200 mm in partially grouted walls

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

for SDC C and D. Joint reinforcement used as

shear reinforcement in fully grouted walls for SDC 𝑉𝑛 ≤ (0.332𝐴𝑛𝑣√𝑓′ )𝛾𝑔 Equation 9-23
�
C and D shall consist of four 5 mm diameter
longitudinal wires at a spacing not to exceed 200 𝛾𝑔 = 0.75 for partially grouted shear walls and 1.0
mm. otherwise.
9.3.4 Design of beams, piers, and columns (c) The maximum value of Vn for Mu/(Vndv)
Member design forces shall be based on an between 0.25 and 1.0 shall be permitted to
analysis that considers the relative stiffness of be linearly interpolated.
structural members. The calculation of lateral 9.3.4.1.2.1 Nominal masonry shear strength —
stiffness shall include the contribution of all Shear strength provided by the masonry, 𝑉𝑛𝑚, shall
beams, piers, and columns. The effects of cracking be calculated using Equation 9-24:
on member stiffness shall be considered.
9.3.4.1 Nominal strength 𝑉𝑛𝑚 = 0.083 × [4.0 −

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

9.3.4.1.1 Nominal axial and flexural strength — 𝑀𝑢

Equation
The nominal axial strength, 𝑃𝑛, and the nominal 1.75 ( )] ×
𝑉𝑢𝑑𝑣 9-24
flexural strength, 𝑀𝑛, of a cross section shall be 𝐴 √𝑓′ + 0.25𝑃
determined in accordance with the design 𝑛𝑣 𝑚 𝑢
assumptions of Section 9.3.2 and the provisions of
this Section. The nominal flexural strength at any 𝑀𝑢/(𝑉𝑢𝑑𝑣) shall be taken as a positive number
section along a member shall not be less than one- and need not be taken greater than 1.0
fourth of the maximum nominal flexural strength 9.3.4.1.2.2 Nominal shear strength provided by
at the critical section. reinforcement — Nominal shear strength provided
The nominal axial compressive strength shall not by shear reinforcement, 𝑉𝑛𝑠, shall be calculated as
exceed Equation 9-19 or Equation 9-20, as follows:
appropriate. 𝐴𝑣
𝑉 = 0.5 ( ) 𝑓 𝑑 Equation 9-25
(a) For members having an h/r ratio not 𝑛𝑠 𝑦 𝑣
𝑠
greater than 99:
𝑃𝑛 = 0.80[0.80𝑓′ (𝐴𝑛 9.3.4.2 Beams — Design of beams shall meet the
− 𝐴𝑠𝑡�) requirements of Section 5.2 and the additional
Equation 9-19 requirements of Sections 9.3.4.2.1 through 9.3.4.2.4.
2
+𝑓𝑦𝐴𝑠𝑡] [1 − ( ℎ ) ] 9.3.4.2.1 The factored axial compressive force on a
140𝑟 beam shall not exceed 0.05𝐴 � ′
𝑛
𝑚
(b) For members having an h/r ratio greater 9.3.4.2.2 Longitudinal reinforcement
than 99:
9.3.4.2.2.1 The variation in longitudinal
𝑃𝑛 = 0.80[0.80𝑓′ (𝐴 reinforcing bars in a beam shall not be greater than
𝑚 𝑛
− 𝐴𝑠𝑡) one bar size. Not more than two bar sizes shall be
Equation 9-20
used in a beam.
2
+𝑓𝑦𝐴𝑠𝑡] (70𝑟 9.3.4.2.2.2 The nominal flexural strength of a
)
ℎ beam shall not be less than 1.3 multiplied by the
nominal cracking moment of the beam, 𝑀𝑐𝑟, the
modulus of
9.3.4.1.2 Nominal shear strength Nominal shear rupture, 𝑓𝑟, for this calculation shall be determined
strength, 𝑉𝑛, shall be calculated using Equation 9- in accordance with Section 9.1.9.2.
21, and shall not be taken greater than the limits
9.3.4.2.2.3 The requirements of Section 9.3.4.2.2.2
given by 9.3.4.1.2 (a) through (c).
need not be applied if at every section the area of
tensile reinforcement provided is at least one-third
𝑉𝑛 = (𝑉𝑛𝑚 + 𝑉𝑛𝑠)𝛾𝑔 Equation 9-21
greater than that required by analysis.
(a) Where Mu/(Vudv) ≤ 0.25: 9.3.4.2.3 Transverse reinforcement — Transverse
𝑉𝑛 ≤ (0.498𝐴𝑛𝑣√𝑓′ ) 𝛾𝑔 Equation 9-22 reinforcement shall be provided where 𝑉𝑢 exceeds
𝑚
𝜙𝑉𝑛𝑚 . The factored shear, 𝑉𝑢, shall include the
(b) Where Mu/(Vudv) ≥ 1.0 effects of lateral load. When transverse

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

reinforcement is required, the following provisions that the reinforcement ratios in both directions are
shall apply: at least 0.001. Distributed flexural reinforcement is
(a) Transverse reinforcement shall be a single to be included in the determination of the actual
bar with a 180-degree hook at each end. reinforcement ratios.
(b) Transverse reinforcement shall be hooked 9.3.4.3 Piers
around the longitudinal reinforcement.
9.3.4.3.1 The factored axial compression force on
(c) The minimum area of transverse ′
piers shall not exceed 0.3𝐴 � 𝑛
reinforcement shall be 0.0007bdv. 𝑚
(d) The first transverse bar shall not be located 9.3.4.3.2 Longitudinal reinforcement — a pier
more than one-fourth of the beam depth, subjected to in-plane stress reversals shall be
dv, from the end of the beam. reinforced symmetrically about the neutral axis of
(e) The maximum spacing shall not exceed the pier. Longitudinal reinforcement of piers shall
one-half the depth of the beam nor 1200 comply with the following:
mm. (a) At least one bar shall be provided in each
9.3.4.2.4 Construction — Beams shall be fully end cell.
grouted. (b) The minimum area of longitudinal
reinforcement shall be 0.0007bd.
9.3.4.2.5 Coupling beams — Structural members
that provide coupling between shear walls shall be 9.3.4.3.3 Dimensional limits — Dimensions shall
designed to reach their moment or shear nominal be in accordance with the following:
strength before either shear wall reaches its (a) The nominal thickness of a pier shall not
moment or shear nominal strength. Analysis of exceed 400 mm.
coupled shear walls shall comply with accepted (b) The distance between lateral supports of a
principles of mechanics. pier shall not exceed 25 multiplied by the
The design shear strength, 𝜙𝑉𝑛, of the coupling nominal thickness of a pier except as
beams shall satisfy the following criterion: provided for in Section 9.3.4.3.3(c).
(c) When the distance between lateral
1.25(𝑀1 + 𝑀2) supports of a pier exceeds 25 multiplied
by the
𝜙𝑉𝑛 ≥ nominal thickness of the pier, design shall
𝐿𝑐 Equation 9-26
+ 1.4𝑉𝑔 be based on the provisions of Section 9.3.5.
(d) The nominal length of a pier shall not be
Where 𝑀1 and 𝑀2 are the normal moment less than three multiplied by its nominal
strength at the ends of the beam, 𝐿𝑐 is the length of thickness nor greater than six multiplied
the beam between the shear walls and 𝑉𝑔 is the by its nominal thickness. The clear height
unfactored shear force due to gravity loads. of a pier shall not exceed five multiplied
by its nominal length.
The calculation of the nominal flexural moment
shall include the reinforcement in reinforced Exception: When the factored axial force at the
concrete roof and floor systems. The width of the location of maximum moment is less than
reinforced concrete used for calculations of 0.05𝑓′ 𝐴 , the length of a pier shall be permitted to
𝑚
reinforcement shall be six times the floor or roof be equal to the thickness of the pier.
slab thickness.
9.3.5 Wall design for out-of-plane loads
9.3.4.2.6 Deep flexural member detailing —
Flexural members with overall-depth-to-clear-span 9.3.5.1 Scope — The requirements of Section 9.3.5
ratio greater than 2/5 for continuous spans or 4/5 shall apply to the design of walls for out-of-plane
for simple spans shall be detailed in accordance loads.
with this section. 9.3.5.2 Nominal axial and flexural strength the
9.3.4.2.6.1 Minimum flexural tension nominal axial strength, 𝑃𝑛, and the nominal
reinforcement shall conform to Section 9.3.4.3.2. flexural strength, 𝑀𝑛, of a cross-section shall be
determined in accordance with the design
9.3.4.2.6.2 Uniformly distributed horizontal and assumptions of Section 9.3.2. The nominal axial
vertical reinforcement shall be provided compressive strength shall not exceed that
throughout the length and depth of deep flexural determined by Equation 9-19 or Equation 9-20, as
members such appropriate.

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

9.3.5.3 Nominal shear strength — The nominal Where:

shear strength shall be determined by Section
9.3.4.1.2. 𝑃𝑢 = 𝑃𝑢𝑤 + 𝑃𝑢𝑓 Equation 9-29
9.3.5.4 P-Delta effects
9.3.5.4.1 Members shall be designed for the The deflection due to factored loads (𝛿𝑢) shall be
obtained using Equation 9-30 and Equation 9-31.
factored axial load, 𝑃𝑢, and the moment magnified
for the effects of member curvature, 𝑀𝑢. The (a) Where Mu < Mcr
magnified moment shall be determined either by 5𝑀𝑢ℎ2
𝛿𝑢 =
Section 9.3.5.4.2 or Section 9.3.5.4.3. 48𝐸 𝐼 Equation 9-30
9.3.5.4.2 Moment and deflection calculations in 𝑚 𝑛

this section are based on simple support conditions (b) Where Mcr ≤ Mu ≤ Mn
top and bottom. For other support and fixity 5𝑀𝑐𝑟ℎ2
conditions, moments and deflections shall be 𝛿𝑢 = 48𝐸 𝐼 +
calculated using established principles of 𝑚 𝑛
Equation 9-31
mechanics. 5(𝑀𝑢 − 𝑀𝑐𝑟)ℎ2
The procedures set forth in this Section shall be 48𝐸𝑚𝐼𝑐𝑟
used when the factored axial load stress at the 9.3.5.4.3 The factored moment, 𝑀𝑢, shall be
location of maximum moment satisfies the determined either by a second-order analysis, or by
requirement calculated by Equation 9-27. a first-order analysis and Equation 9-32 through
𝑃𝑢 Equation 9-34.
( ) ≤ 0.20𝑓′ Equation 9-27
𝐴𝑔 𝑚 𝑀𝑢 = 𝜓𝑀𝑢, 0 Equation 9-32

When the ratio of effective height to nominal

Where 𝑀𝑢, 𝑜 is the factored moment from first-order
thickness, ℎ/𝑡, exceeds 30, the factored axial stress analysis.
shall not exceed 0.05𝑓′ .
A nominal thickness of�100 mm is permitted where 𝜓= 1
load-bearing reinforced hollow clay unit masonry 𝑃𝑢 Equation 9-33
1−
walls satisfy all of the following conditions. 𝑃𝑒
(1) The maximum unsupported height-to- Where:
thickness or length-to-thickness ratios do
not exceed 27. 𝜋2𝐸𝑚𝐼𝑒𝑓𝑓
𝑃𝑒 Equation 9-34
(2) The net area unit strength exceeds 55 MPa.
= ℎ2
(3) Units are laid in running bond.
For 𝑀𝑢 < 𝑀𝑐𝑟 , 𝐼𝑒𝑓𝑓 shall be taken as 0.75𝐼𝑛. For
(4) Bar sizes do not exceed 12 mm. 𝑀𝑢 ≥ 𝑀𝑐𝑟, 𝐼𝑒𝑓𝑓 shall be taken as 𝐼𝑐𝑟 𝑃𝑢/𝑃𝑒 cannot
(5) There are no more than two bars or one exceed 1.0.
splice in a cell. 9.3.5.4.4 The cracking moment of the wall shall be
(6) Joints are not raked. calculated using the modulus of rupture, 𝑓𝑟, taken
from Table 9.1.
Factored moment and axial force shall be
determined at the mid height of the wall and shall 9.3.5.4.5 The neutral axis for determining the
be used for design. The factored moment, 𝑀𝑢, at cracked moment of inertia, 𝐼𝑐𝑟, shall be determined
the midheight of the wall shall be calculated in accordance with the design assumptions of
using Section 9.3.2. The effects of axial load shall be
Equation 9-28. permitted to be included when calculating 𝐼𝑐𝑟.
Unless stiffness values are obtained by a more
𝑤𝑢ℎ2
𝑀𝑢 = + comprehensive analysis, the cracked moment of
𝑒𝑢 8 Equation 9-28 inertia for a wall that is partially or fully grouted
𝑃𝑢𝑓 + 𝑃𝑢𝛿𝑢 and whose neutral axis is in the face shell shall be
2
SBC 305-CR- 5
CHAPTER 9—STRENGTH DESIGN OF

obtai
ned
from
Equa
tion
9-35
and
Equa
tion
9-36.

SBC 305-CR- 5
 CHAPTER 9—STRENGTH DESIGN OF

𝑃𝑢 𝑡𝑠𝑝 9.3.6.5.1 Special boundary elements need not be

𝐼𝑐𝑟 = 𝑛 (𝐴𝑠 )× provided in shear walls meeting the following
+ 𝑓𝑦 2𝑑 conditions:
Equation 9-35
𝑏𝑐3 (1) 𝑃 ≤ 0.10𝐴 𝑓′ for geometrically
(𝑑 − 𝑐)2 + 𝑢 𝑔 𝑚
3 symmetrical wall sections
𝑃𝑢 ≤ 0.05𝐴 𝑓′ for geometrically
𝐴𝑠𝑓𝑦 + 𝑔 𝑚
𝑃 Equation 9-36 unsymmetrical wall sections; and either
𝑐= 𝑢 ′ 𝑀𝑢
0.64𝑓 𝑏 (2) ≤ 1.0; or
�
9.3.5.5 Deflections — The horizontal mid height 𝑉𝑢𝑑𝑣
𝑀𝑢
deflection, 𝛿𝑠, under allowable stress design load (3) 𝑉 ≤ 0.25𝐴 √𝑓′ 𝑎𝑛𝑑 ≤ 3.0
combinations shall be limited by the relation: 𝑢 𝑛𝑣 𝑚 𝑉𝑢𝑑𝑣

9.3.6.5.2 The need for special boundary elements

𝛿𝑆 < 0.007ℎ Equation 9-37 at the edges of shear walls shall be evaluated
in
P-delta effects shall be included in deflection accordance with Section 9.3.6.5.3 or 9.3.6.5.4. The
calculation using either Section 9.3.5.5.1 or Section requirements of Section 9.3.6.5.5 shall also be
9.3.5.5.2. satisfied.
9.3.5.5.1 For simple support conditions top and 9.3.6.5.3 This Section applies to walls bending in
bottom, the mid height deflection, 𝛿 𝑠, shall be single curvature in which the flexural limit state
response is governed by yielding at the base of the
calculated using either Equation 9-30 or Equation wall. Walls not satisfying those requirements shall
9-31, as applicable, and replacing 𝑀𝑢 with 𝑀𝑠𝑒𝑟 and be designed in accordance with Section 9.3.6.5.4.
𝛿𝑢 with 𝛿𝑠.
(a) Special boundary elements shall be
9.3.5.5.2 The deflection, 𝛿𝑠, shall be determined provided over portions of compression
by a second-order analysis that includes the effects zones where:
of cracking, or by a first-order analysis with the
calculated deflections magnified by a factor of 𝑙𝑤
1/(1– 𝑃/𝑃 ), where 𝑃 is determined from Equation 𝑐 ≥ 600(𝐶𝑑𝛿𝑛𝑒/ℎ𝑤)
𝑒 𝑒
9-34. and 𝑐 is calculated for the 𝑃𝑢 given by SBC 301
Strength Design Load Combination 5 (1.2𝐷 +
9.3.6 Wall design for in-plane loads 1.0𝐸 + 𝐿 + 0.2𝑆) or the corresponding strength
9.3.6.1 Scope — The requirements of Section 9.3.6 design load combination of SBC301, and the
shall apply to the design of walls to resist in-plane corresponding nominal moment strength, 𝑀𝑛, at
loads. the base critical section. The load factor on 𝐿 in
Combination 5 is reducible to 0.5, as per
9.3.6.2 Reinforcement — Reinforcement shall be exceptions to Section 2.3.2 of SBC 301.
provided perpendicular to the shear reinforcement
and shall be at least equal to one-third. The (b) Where special boundary elements are
reinforcement shall be uniformly distributed and required by Section 9.3.6.5.3(a), the special
shall not exceed a spacing of 2.40 m. boundary element reinforcement shall
extend vertically from the critical section a
9.3.6.3 Flexural and axial strength — The nominal distance not less than the larger of 𝑙𝑤, or
flexural and axial strength shall be determined in
𝑀𝑢/4𝑉𝑢.
accordance with Section 9.3.4.1.1.
9.3.6.5.4 Shear walls not designed by Section
9.3.6.4 Shear strength — The nominal shear 9.3.6.5.3 shall have special boundary elements at
strength shall be calculated in accordance with boundaries and edges around openings in shear
Section 9.3.4.1.2. walls where the maximum extreme fiber
9.3.6.5 The maximum reinforcement requirements compressive stress, corresponding to factored
of Section 9.3.3.5 shall not apply if a shear wall is forces including earthquake effect, exceeds 0.2𝑓′ .
�
designed to satisfy the requirements of 9.3.6.5.1 The special boundary element shall be permitted to
through 9.3.6.5.5. be discontinued where the calculated compressive
stress is less than 0.15𝑓′ . Stresses shall be
�
calculated for the factored forces using a linearly

SBC 305-CR- 6
 CHAPTER 9—STRENGTH DESIGN OF

elastic model and gross section properties. For constructed shall have a minimum surface
walls with flanges, an effective flange width as roughness of 3 mm. Shear keys are required where
defined in Section 5.1.1.2.3 shall be used. the calculated tensile strain in vertical
9.3.6.5.5 Where special boundary elements are reinforcement from in-plane loads exceeds the
required by Section 9.3.6.5.3 or 9.3.6.5.4, yield strain under load combinations that include
requirements (a) through (d) in this section shall be seismic forces based on an 𝑅 factor equal to 1.5.
satisfied and tests shall be performed to verify the Shear keys that satisfy the following requirements
strain capacity of the element: shall be placed at the interface between the wall
and the foundation.
(a) The special boundary element shall extend
horizontally from the extreme (1) The width of the keys shall be at least
compression fiber a distance not less than equal to the width of the grout space.
the larger of (c − 0.1lw) and c/2. (2) The depth of the keys shall be at least 40
(b) In flanged sections, the special boundary mm.
element shall include the effective flange
width in compression and shall extend at (3) The length of the key shall be at least 150
least 300 mm into the web. mm.
(c) Special boundary element transverse (4) The spacing between keys shall be at least
reinforcement at the wall base shall extend equal to the length of the key.
into the support a minimum of the
development length of the largest (5) The cumulative length of all keys at each
longitudinal reinforcement in the boundary end of the shear wall shall be at least 10
element unless the special boundary percent of the length of the shear wall (20
element terminates on a footing or mat, percent total).
where special boundary element transverse (6) At least 150 mm of a shear key shall be
reinforcement shall extend at least 300 placed within 400 mm of each end of the
mm into the footing or mat. wall.
(d) Horizontal shear reinforcement in the wall
web shall be anchored to develop the (7) Each key and the grout space above each
specified yield strength, fy, within the key in the first course of masonry shall be
confined core of the boundary element. grouted solid.

9.3.6.6 Shear keys — The surface of concrete

upon which a special reinforced masonry shear
wall is

SBC 305-CR- 6
 CHAPTER 9—STRENGTH DESIGN OF

TABLES OF CHAPTER 9

Table 9.1: Modulus of rupture, 𝒇𝒓, kPa

Direction of flexural tensile stress and Mortar types

masonry type
Portland cement/lime or mortar Masonry cement or air
cement entrained Portland cement/lime

M or S N M or S N
Normal to bed joints
Solid units 919 690 552 349
Hollow units1
Ungrouted 579 441 349 211
Fully grouted 1124 1089 1055 1000
Parallel to bed joints in running bond
Solid units 1839 1379 1103 689
Hollow units
Ungrouted and partially grouted 1149 873 689 441
Fully grouted 1839 1379 1103 689
Parallel to bed joints in masonry not laid in
running bond
Continuous grout section parallel to bed 2310 2310 2310 2310
Other 0 0 0 0
1. For partially grouted masonry, modulus of rupture values shall be determined on the basis of linear interpolation
between fully grouted hollow units and ungrouted hollow units based on amount (percentage) of grouting.

SBC 305-CR- 6
CHAPTER 10—PRESTRESSED

CHAPTER 10—PRESTRESSED MASONRY

Prestressed Masonry
requirements were omitted
from this version of the code as
they may not be of practical
use in Saudi Arabia.

SBC 305-CR- 6
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED

AERATED CONCRETE (AAC) MASONRY

11.1.5.1 Anchor bolts — For cases where the

11.1 —General
nominal strength of an anchor bolt is controlled by
11.1.1 Scope AAC masonry breakout, 𝜙 shall be taken as 0.50.
For cases where the nominal strength of an anchor
This Chapter provides minimum requirements for
bolt is controlled by anchor bolt steel, 𝜙 shall be
design of AAC masonry.
taken as 0.90. For cases where the nominal
11.1.1.1 Except as stated elsewhere in this strength of an anchor bolt is controlled by anchor
Chapter, design of AAC masonry shall comply pullout, 𝜙 shall be taken as 0.65.
with the requirements of Part 1 and Part 2,
11.1.5.2 Bearing — For cases involving bearing
excluding Sections 5.5.1, 5.5.2(d) and 5.3.2.
on AAC masonry, 𝜙 shall be taken as 0.60.
11.1.1.2 Design of AAC masonry shall comply
11.1.5.3 Combinations of flexure and axial load in
with Sections 11.1.2 through 11.1.9, and either
unreinforced AAC masonry — the value of 𝜙 shall
Section 11.2 or 11.3.
be taken as 0.60 for unreinforced AAC masonry
11.1.2 Required strength designed to resist flexure, axial load, or
combinations thereof.
Required strength shall be determined in
accordance with the strength design load 11.1.5.4 Combinations of flexure and axial load in
combinations of SBC 301. Members subject to reinforced AAC masonry — The value of 𝜙 shall
compressive axial load shall be designed for the be taken as 0.90 for reinforced AAC masonry
maximum design moment accompanying the axial designed to resist flexure, axial load, or
load. The factored moment, 𝑀𝑢, shall include the combinations thereof.
moment induced by relative lateral displacement.
11.1.5.5 Shear — The value of 𝜙 shall be taken as
11.1.3 Design strength 0.80 for AAC masonry designed to resist shear.
AAC masonry members shall be proportioned so 11.1.6 Deformation requirements
that the design strength equals or exceeds the
11.1.6.1 Deflection of unreinforced (plain) AAC
required strength. Design strength is the nominal
masonry — Deflection calculations for
strength multiplied by the strength-reduction factor,
unreinforced (plain) AAC masonry members shall
𝜙, as specified in Section 11.1.5.
be based on uncracked section properties.
11.1.4 Strength of joints 11.1.6.2 Deflection of reinforced AAC masonry —
AAC masonry members shall be made of AAC Deflection calculations for reinforced AAC
masonry units. The tensile bond strength of AAC masonry members shall be based on cracked
masonry joints shall not be taken greater than the section properties including the reinforcement and
limits of Section 11.1.8.3. When AAC masonry grout. The flexural and shear stiffness properties
units with a maximum height of 200 mm assumed for deflection calculations shall not
(nominal) are used, head joints shall be permitted exceed one-half of the gross section properties
to be left unfilled between AAC masonry units laid unless a cracked- section analysis is performed.
in running bond, provided that shear capacity is
11.1.7 Anchor bolts
calculated using the formulas of this Code
corresponding to that condition. Open head joints Headed and bent-bar anchor bolts shall be
shall not be permitted in AAC masonry not laid in embedded in grout, and shall be designed in
running bond. accordance with Section 9.1.6 using 𝑓′ instead of
�
𝑓′ , and neglecting the contribution of AAC to the
11.1.5 Strength-reduction factors �
edge distance and embedment depth. Anchors
embedded in AAC without grout shall be designed

SBC 305-CR- 6
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

using nominal capacities provided by the anchor 11.1.9.1 The nominal bearing strength of AAC
manufacturer and verified by an independent masonry shall be calculated as 𝑓′ multiplied by
testing agency. 𝐴
the bearing area, 𝐴𝑏𝑟, as defined in Section 4.3.4.
11.1.8 Material properties 11.1.9.2 Bearing for simply supported precast
11.1.8.1 Compressive strength floor and roof members on AAC masonry shear
walls — The following minimum requirements
11.1.8.1.1 Masonry compressive strength — The shall apply so that after the consideration of
specified compressive strength of AAC masonry, tolerances, the distance from the edge of the
𝑓′ shall equal or exceed 2.0 MPa supporting wall to the end of the precast member
𝐴
11.1.8.1.2 Grout compressive strength — The in the direction of the span is at least:
specified compressive strength of grout, 𝑓’𝑔, shall (a) For AAC floor panels, 50 mm
equal or exceed 14.0 MPa and shall not exceed 34 (b) For solid or hollow-core slabs, 50 mm
MPa. (c) For beams or stemmed members, 75 mm
11.1.8.2 Masonry splitting tensile strength — The 11.1.10 Corbels — Load-bearing corbels
splitting tensile strength fc shall be determined by of AAC masonry shall not be permitted. Non-load-
Equation 11-1. bearing corbels of AAC masonry shall conform to
the requirements of Section 5.5.2(a) through
𝑓𝑡 5.5.2(c). The back section of the corbelled section
= 0.199√𝑓′ Equation 11-1
𝐴𝐴𝐶 𝐴 shall remain within 6.5 mm of plane.
11.2 —Unreinforced (plain) AAC
11.1.8.3 Masonry modulus of rupture — The
modulus of rupture, 𝑓𝑟𝐴𝐴𝐶 , for AAC masonry masonry
elements shall be taken as twice the masonry 11.2.1 Scope
splitting tensile strength, 𝑓𝑡𝐴𝐴𝐶 . If a section of
AAC masonry contains a Type M or Type S The requirements of Section 11.2 are in addition to
horizontal leveling bed of mortar, the value of the requirements of Part 1, Part 2, and Section
𝑓𝑟𝐴𝐴𝐶 shall not exceed 345 kPa at that section. If a 11.1, and govern masonry design in which AAC
section of AAC masonry contains a horizontal bed masonry is used to resist tensile forces.
joint of thin-bed mortar and AAC, the value of 11.2.1.1 Strength for resisting loads —
𝑓𝑟𝐴𝐴𝐶 shall not exceed 550 kPa at that section. Unreinforced (plain) AAC masonry members shall
11.1.8.4 Masonry direct shear strength — The be designed using the strength of masonry units,
direct shear strength, 𝑓𝑣 across an interface of mortar, and grout in resisting design loads.
AAC material shall be determined by Equation 11- 11.2.1.2 Strength contribution from reinforcement
2, and — Stresses in reinforcement shall not be
shall be taken as 345 kPa across an interface considered effective in resisting design loads.
between grout and AAC material.
11.2.1.3 Design criteria — Unreinforced (plain)
𝑓𝑣 = 0.15𝑓′ Equation 11-2
𝐴 AAC masonry members shall be designed to
remain
11.1.8.5 Coefficient of friction — The coefficient uncracked.
of friction between AAC and AAC shall be 0.75.
The coefficient of friction between AAC and thin-
11.2.2 Flexural strength of unreinforced (plain)
AAC masonry members
bed mortar or between AAC and leveling-bed
mortar shall be 1.0. The following assumptions shall apply when
determining the flexural strength of unreinforced
11.1.8.6 Reinforcement strength — Masonry
design shall be based on a reinforcement strength (plain) AAC masonry members:
equal to the specified yield strength of (a) Strength design of members for factored
reinforcement, 𝑓𝑦, which shall not exceed 414 flexure and axial load shall be in
MPa. The actual yield strength shall not exceed 1.3 accordance with principles of engineering
multiplied by the specified yield strength. mechanics.
(b) Strain in masonry shall be directly
11.1.9 Nominal bearing strength proportional to the distance from the
neutral axis.

SBC 305-CR- 6
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

(c) Flexural tension in masonry shall be 11.3 —Reinforced AAC masonry

assumed to be directly proportional to
strain. 11.3.1 Scope
(d) Flexural compressive stress in
The requirements of this section are in addition to
combination with axial compressive stress
the requirements of Part 1, Part 2, and Section 11.1
in masonry shall be assumed to be directly
and govern AAC masonry design in which
proportional to strain. Nominal
reinforcement is used to resist tensile forces.
compressive strength shall not exceed a
stress corresponding to 0.85f ′ 11.3.2 Design assumptions
A
(e) The nominal flexural tensile strength of The following assumptions apply to the design of
AAC masonry shall be determined from reinforced AAC masonry:
Section 11.1.8.3.
(a) There is strain compatibility between the
11.2.3 Nominal axial strength of unreinforced reinforcement, grout, and AAC masonry.
(plain) AAC masonry members (b) The nominal strength of reinforced AAC
Nominal axial strength, 𝑃𝑛, shall be calculated using masonry cross sections for combined
Equation 11-3 or Equation 11-4. flexure and axial load shall be based on
applicable conditions of equilibrium.
(a) For members having an h/r ratio not
(c) The maximum usable strain, εmu, at the
greater than 99: extreme AAC masonry compression fiber
0.85𝐴𝑛𝑓′ shall be assumed to be 0.0012 for Class 2
𝑃𝑛 = 0.8 { 𝐴𝐴𝐶
× AAC masonry and 0.003 for Class 4 AAC
1 masonry and higher.
Equation 11-3
2 (d) Strain in reinforcement and AAC masonry
[1 − ℎ ) ]} shall be assumed to be directly
( 140𝑟 proportional to the distance from the
neutral axis.
(b) For members having an h/r ratio greater (e) Tension and compression stresses in
than 99: reinforcement shall be calculated as the
0.85𝐴
′ product of steel modulus of elasticity, Es,
𝑛 𝑓𝐴𝐴𝐶
and steel strain, εs, but shall not be greater
𝑃𝑛 = 0.8 { × than fy. Except as permitted in Section
1 Equation 11-4
70𝑟 2 11.3.3.5 for determination of maximum
[( ) ]}
ℎ area of flexural reinforcement, the
compressive stress of steel reinforcement
11.2.4 Axial tension shall be neglected unless lateral restraining
reinforcement is provided in compliance
The tensile strength of unreinforced AAC masonry with the requirements of Section 5.3.1.4.
shall be neglected in design when the masonry is (f) The tensile strength of AAC masonry shall
subjected to axial tension forces. be neglected in calculating axial and
11.2.5 Nominal shear strength of unreinforced flexural strength.
(plain) AAC masonry members (g) The relationship between AAC masonry
compressive stress and masonry strain
The nominal shear strength of AAC masonry, shall be assumed to be defined by the
following:
𝑉𝑛𝐴𝐴𝐶 , shall be the least of the values calculated by A
AAC masonry stress of 0.85f ′ shall be
Sections 11.3.4.1.2.1 through 11.3.4.1.2.3. In in accordance with Section 11.3.6.5.
evaluating nominal shear strength by Section
11.3.4.1.2.3, effects of reinforcement shall be
neglected. The provisions of 11.3.4.1.2 shall apply
to AAC shear walls not laid in running bond. The
provisions of Section 11.3.4.1.2.4 shall apply to
AAC walls loaded out-of-plane.
11.2.6 Flexural cracking
The flexural cracking strength shall be calculated

SBC 305-CR- 6
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

assumed uniformly distributed

over an equivalent
compression stress block
bounded by edges of the cross
section and a straight line
parallel to the neutral axis and
located at a distance a = 0.67c
from the fiber of maximum
compressive strain. The
distance c from the fiber of
maximum strain to the neutral
axis shall be measured
perpendicular to the neutral
axis.
11.3.3 Reinforcement requirements and details

SBC 305-CR- 6
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

11.3.3.1 Reinforcing bar size limitations — member, d/2, and the start of the hook
Reinforcing bars used in AAC masonry shall not (point of tangency).
be larger than Dia 28. The nominal bar diameter (b) For Dia 16 bars and smaller, bending
shall not exceed one-eighth of the nominal around longitudinal reinforcement through
member thickness and shall not exceed one-quarter at least 135 degrees plus an embedment of
of the least clear dimension of the grout space in ld/3. The ld/3 embedment of a stirrup leg
which it is placed. In plastic hinge zones, the area shall be taken as the distance between mid-
of reinforcing bars placed in a grout space shall depth of the member, d/2, and the start of
not exceed 3 percent of the grout space area. In the hook (point of tangency).
other than plastic hinge zones, the area of (c) Between the anchored ends, each bend in
reinforcing bars placed in a grout space shall not the continuous portion of a transverse U-
exceed 4.5 percent of the grout space area. stirrup shall enclose a longitudinal bar.
11.3.3.2 Standard hooks — The equivalent 11.3.3.3.2.2 At wall intersections, horizontal
embedment length to develop standard hooks in reinforcing bars needed to satisfy shear strength
tension, 𝑙𝑒, shall be determined by Equation 11-5: requirements of Section 11.3.4.1.2 shall be bent
around the edge vertical reinforcing bar with a 90-
𝑙𝑒 = 13𝑑𝑏 Equation 11-5 degree standard hook and shall extend horizontally
into the intersecting wall a minimum distance at
11.3.3.3 Development
least equal to the development length.
11.3.3.3.1 Development of tension and
11.3.3.4 Splices — Reinforcement splices shall
compression reinforcement — the required tension
comply with one of the following:
or compression reinforcement shall be developed
in accordance with the following provisions: (a) The minimum length of lap for bars shall be
300 mm or the development length
The required development length of reinforcement
determined by Equation 11-6, whichever is
shall be determined by Equation 11-6, but shall not
greater.
be less than 300 mm.
(b) A welded splice shall have the bars butted
and welded to develop at least 125 percent
𝑙 = 1.57𝑑2𝑓 𝛾
𝑏𝑦
of the yield strength, fy , of the bar in tension
𝑑 Equation 11-6 or compression, as required. Welding shall
𝐾𝐴𝐴𝐶 √𝑓′
� conform to AWS D1.4. Reinforcement to
be welded shall conform to ASTM A706,
𝐾𝐴𝐴𝐶 shall not exceed the smallest of the or shall be accompanied by a submittal
following: the minimum grout cover, the clear showing its chemical analysis and carbon
spacing between adjacent reinforcement splices, equivalent as required by AWS D1.4.
and 9𝑑𝑏. Existing reinforcement to be welded shall
(a) γ= 1.0 for Dia 10 through Dia 16 bars; conform to ASTM A706, or shall be
(b) 𝛾 = 1.3 for Dia 18 through Dia 22 bars analyzed chemically and its carbon
(c) 𝛾 = 1.5 for Dia 25 through Dia 28 bars. equivalent determined as required by
AWS D1.4.
11.3.3.3.2 Development of shear reinforcement — (c) Mechanical splices shall have the bars
Shear reinforcement shall extend the depth of the connected to develop at least 125 percent
member less cover distances. of the yield strength, fy, of the bar in
11.3.3.3.2.1 Except at wall intersections, the end tension or compression, as required.
of a horizontal reinforcing bar needed to satisfy 11.3.3.5 Maximum reinforcement percentages —
shear strength requirements of Section 11.3.4.1.2, The ratio of reinforcement, 𝜌, shall be calculated
shall be bent around the edge vertical reinforcing in accordance with Section 9.3.3.5 with the
bar with a 180-degree hook. The ends of single-leg following exceptions:
or U- stirrups shall be anchored by one of the
following means: The maximum usable strain, 𝜀𝑚𝑢, at the extreme
masonry compression fiber shall be in accordance
(a) A standard hook plus an effective with Section 11.3.2(c).
embedment of ld/2. The effective
embedment of a stirrup leg shall be taken
as the distance between the mid-depth of
the

SBC 305-CR- 6
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

The strength of the compression zone shall be where 𝑉𝑛 shall not exceed the following:
calculated as 85 percent of 𝑓′ multiplied by 67
percent of the area of the compression
𝐴 zone. 𝑉𝑛 = 𝜇𝐴𝐴𝐶 𝑃𝑢 Equation 11-10
11.3.3.6 Bundling of reinforcing bars —
Reinforcing bars shall not be bundled. At an interface of AAC and thin-bed mortar or
leveling-bed mortar, the nominal sliding shear
11.3.4 Design of beams, piers, and columns strength shall be calculated using Equation 11-10
Member design forces shall be based on an and using the coefficient of friction from Section
analysis that considers the relative stiffness of 11.1.8.5.
structural members. The calculation of lateral (a) Where Mu/(Vudv) ≤ 0.25:
stiffness shall include the contribution of beams,
piers, and columns. The effects of cracking on 𝑉𝑛 ≤ 0.498𝐴𝑛𝑣√𝑓′ Equation 11-11
member stiffness shall be considered. 𝐴

11.3.4.1 Nominal strength (b) Where Mu/(Vudv) ≥ 1.0:

11.3.4.1.1 Nominal axial and flexural strength — 𝑉𝑛 ≤ 0.332𝐴𝑛𝑣√𝑓′ Equation 11-12
The nominal axial strength, 𝑃𝑛, and the nominal 𝐴
flexural strength, 𝑀𝑛, of a cross section shall be (c) The maximum value of 𝑉𝑛 for 𝑀𝑢/(𝑉𝑢 𝑑𝑣)
determined in accordance with the design between 0.25 and 1.0 shall be permitted to
assumptions of Section 11.3.2 and the provisions of be linearly interpolated.
Section 11.3.4.1. For any value of nominal flexural
strength, the corresponding calculated nominal The nominal masonry shear strength shall be taken
axial strength shall be modified for the effects of as the least of the values calculated using Section
slenderness in accordance with Equation 11-7 or 11.3.4.1.2.1 and 11.3.4.1.2.2.
Equation 11-8. The nominal flexural strength at any 11.3.4.1.2.1 Nominal masonry shear strength as
section along a member shall not be less than one- governed by web-shear cracking — Nominal
fourth of the maximum nominal flexural strength masonry shear strength as governed by web-shear
at the critical section. cracking, 𝑉𝑛𝐴𝐴𝐶 , shall be calculated using Equation
The nominal axial compressive strength shall not 11-13a for AAC masonry with mortared head joints,
exceed Equation 11-7 or Equation 11-8, as and Equation 11-13b for masonry with unmortared
appropriate. head joints:

(a) For members having an h/r ratio not

𝑉𝑛𝐴𝐴𝐶 Equation
greater than 99: 𝑃𝑢
= 0.0789𝑙 𝑡√𝑓′ √1 + 11-13a
𝐴𝐴𝐶
𝑃𝑛 = 0.80[0.85𝑓 (𝐴𝑛′ � 0.199√𝑓′ 𝑙𝑤𝑡
𝐴 𝐴
− 𝐴𝑠𝑡)
2 Equation 11-7 𝑉𝑛𝐴𝐴𝐶 Equation
ℎ
+𝑓𝑦𝐴𝑠𝑡] [1 − ( )] = 0.0548𝑙 ′
𝑡√𝑓 1+ 𝑃𝑢 11-14b
140𝑟 𝑤 𝐴𝐴𝐶 √
0.199√𝑓′ 𝑙𝑤𝑡
(b) For members having an h/r ratio greater 𝐴
than 99:
For AAC masonry not laid in running bond,
𝑃𝑛 = 0.80[0.85𝑓′ (𝐴𝑛 nominal masonry shear strength as governed by
𝐴
− 𝐴𝑠𝑡) web-shear cracking, 𝑉𝑛𝐴𝐴𝐶 , shall be calculated
2 Equation 11-8 using Equation 11-13c:
+𝑓𝑦𝐴𝑠𝑡] (70𝑟 )
ℎ 𝑉𝑛𝐴𝐴𝐶 = 0.0747√𝑓′ 𝐴𝑛𝑣 Equation 11 13c
𝐴
11.3.4.1.2 Nominal shear strength Nominal shear + 0.05𝑃𝑢
strength, 𝑉𝑛, shall be calculated using Equation 11-9
through Equation 11-12, as appropriate. 11.3.4.1.2.2 Nominal shear strength as governed
by crushing of diagonal compressive strut — For
walls
𝑉𝑛 with 𝑀𝑢/(𝑉𝑢𝑑𝑣) < 1.5, nominal shear strength,
= 𝑉𝑛𝐴𝐴𝐶 + 𝑉𝑛𝑠 Equation 11-9
𝑉𝑛𝐴𝐴𝐶 , as governed by crushing of a diagonal strut,

SBC 305-CR- 6
CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

s
h
a
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l
b
e
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:

SBC 305-CR- 7
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

𝑉𝑛𝐴𝐴𝐶
(a) Transverse reinforcement shall be a single
ℎ. 𝑙2
= 0.17𝑓 ′
𝑡 𝑤
bar with a 180-degree hook at each end.
Equation 11-15 (b) Transverse reinforcement shall be hooked
𝐴𝐴𝐶 2 3
ℎ +( 𝑙 ) 2 around the longitudinal reinforcement.
4 � (c) The minimum area of transverse
For walls with 𝑀 /(𝑉 𝑑 ) equal to or exceeding
reinforcement shall be 0.0007bdv.
𝑢 𝑢 𝑣 (d) The first transverse bar shall not be located
1.5, capacity as governed by crushing of the more than one-fourth of the beam depth,
diagonal compressive strut need not be calculated.
dv, from the end of the beam.
11.3.4.1.2.3 Nominal shear strength provided by (e) The maximum spacing shall not exceed the
shear reinforcement — Nominal shear strength lesser of one-half the depth of the beam or
provided by reinforcement, 𝑉𝑛𝑠, shall be calculated 1200 mm.
as follows: 11.3.4.2.4 Construction — Beams shall be fully
𝐴𝑣 grouted.
𝑉 = 0.50 ( ) 𝑓 𝑑 Equation 11-16
𝑛𝑠 11.3.4.2.5 Dimensional limits — The nominal
𝑠 𝑦 𝑣
depth of a beam shall not be less than 200 mm.
Nominal shear strength provided by reinforcement, 11.3.4.3 Piers
𝑉𝑛𝑠, shall include only deformed reinforcement
embedded in grout for AAC shear walls. 11.3.4.3.1 The factored axial compression force on
the piers shall not exceed 0.3𝐴𝑛𝑓′ .
11.3.4.1.2.4 Nominal shear strength for beams and 𝐴
for out-of-plane loading of other members shall be 11.3.4.3.2 Longitudinal reinforcement — A pier
calculated as follows: subjected to in-plane stress reversals shall be
reinforced symmetrically about the geometric
𝑉𝑛𝐴𝐴𝐶 center of the pier. The longitudinal reinforcement
of piers shall comply with the following:
Equation 11-17
= 0.066√𝑓′ 𝐴 𝑏𝑑 (a) At least one bar shall be provided in each
end cell.
11.3.4.2 Beams — Design of beams shall meet the (b) The minimum area of longitudinal
requirements of Section 5.2 and the additional reinforcement shall be 0.0007bd.
requirements of Sections 11.3.4.2.1 through
11.3.4.2.5. 11.3.4.3.3 Dimensional limits — Dimensions shall
be in accordance with the following:
11.3.4.2.1 The factored axial compressive force on
a beam shall not exceed 0.05𝐴𝑛𝑓′ . (a) The nominal thickness of a pier shall not
𝐴 be less than 150 mm and shall not exceed
11.3.4.2.2 Longitudinal reinforcement 400 mm.
11.3.4.2.2.1 The variation in longitudinal (b) The distance between lateral supports of a
reinforcing bars shall not be greater than one bar pier shall not exceed 25 multiplied by the
size. Not more than two bar sizes shall be used in a nominal thickness of a pier except as
beam. provided for in Section 11.3.4.3.3(c).
(c) When the distance between lateral
11.3.4.2.2.2 The nominal flexural strength of a supports of a pier exceeds 25 multiplied by
beam shall not be less than 1.3 multiplied by the the nominal thickness of the pier, design
nominal cracking moment of the beam, 𝑀𝑐𝑟. The
shall be based on the provisions of Section
modulus of rupture, 𝑓𝑟𝐴𝐴𝐶 , for this calculation 11.3.5.
shall be determined in accordance with Section (d) The nominal length of a pier shall not be
11.1.8.3.
less than three multiplied by its nominal
11.3.4.2.3 Transverse reinforcement — Transverse thickness nor greater than six multiplied
reinforcement shall be provided where 𝑉𝑢 exceeds by its nominal thickness. The clear height
𝜙𝑉𝑛𝐴𝐴𝐶 . The factored shear, 𝑉𝑢, shall include the of a pier shall not exceed five multiplied
effects of lateral load. When transverse by its nominal length.
reinforcement is required, the following provisions (e) Exception: When the factored axial force
shall apply: at the location of maximum moment is less
than 0.05f ′ Ag, the length of a pier shall
A

SBC 305-CR- 7
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

be permitted to be taken equal to the

thickness of the pier. 𝑤 ℎ2
𝑀 = 𝑢 +𝑃 𝛿
𝑢 𝑢 𝑢
11.3.5 Wall design for out-of-plane loads 8 Equation 11-19
𝑒
𝑢
11.3.5.1 Scope — The requirements of Section +𝑃𝑢𝑓
11.3.5 shall apply to the design of walls for out-of- 2
plane loads. Where:
11.3.5.2 Maximum reinforcement — The
maximum reinforcement ratio shall be determined 𝑃𝑢 = 𝑃𝑢𝑤 + 𝑃𝑢𝑓 Equation 11-20
by Section 11.3.3.5.
The deflection due to factored loads (𝛿𝑢) shall be
11.3.5.3 Nominal axial and flexural strength the obtained using Equation 11-21 and Equation 11-22.
nominal axial strength, 𝑃𝑛, and the nominal
flexural (a) Where Mu < Mcr
strength, 𝑀𝑢, of a cross-section shall be determined
in accordance with the design assumptions of 5𝑀𝑢ℎ2 Equation 11-21
Section 11.3.2. The nominal axial compressive 𝛿𝑢 =
48𝐸 𝐼
𝐴𝐴𝐶 𝑛
strength shall not exceed that determined by
(b) Where Mcr ≤ Mu ≤ Mn
Equation 11-7 or Equation 11-8, as appropriate.
2
11.3.5.4 Nominal shear strength — The nominal 𝛿𝑢 = 5𝑀𝑐𝑟ℎ
48𝐸 𝐼
shear strength shall be determined by Section 𝐴𝐴𝐶 𝑛
11.3.4.1.2. Equation 11-22
5(𝑀𝑢 − 𝑀𝑐𝑟)ℎ2
11.3.5.5 P-Delta effects +
48𝐸𝐴𝐴𝐶 𝐼𝑐𝑟
11.3.5.5.1 Members shall be designed for the
factored axial load, 𝑃𝑢, and the moment magnified 11.3.5.5.3 The factored moment, 𝑀𝑢, shall be
for the effects of member curvature, 𝑀𝑢. The determined either by a second-order analysis, or by
magnified moment shall be determined either by a first-order analysis and Equation 11-23 through
Section 11.3.5.5.2 or Section 11.3.5.5.3. Equation 11-25.
11.3.5.5.2 Moment and deflection calculations in
𝑀𝑢 = 𝜓𝑀𝑢, 0 Equation 11-23
this Section are based on simple support
conditions top and bottom. For other support and
fixity conditions, moments, and deflections shall Where 𝑀𝑢, 0 is the factored moment from first-
be calculated using established principles of order analysis.
mechanics. 1
The procedures set forth in this section shall be 𝜓= 𝑃𝑢 Equation 11-24
1−
used when the factored axial load stress at the 𝑃𝑒
location of maximum moment satisfies the
requirement calculated by Equation 11-18. Where:
𝑃𝑢
≤ 0.2𝑓′ Equation 11-18 𝜋2𝐸𝐴𝐴𝐶 𝐼𝑒𝑓𝑓
𝑃𝑒 2
Equation 11-25
=
𝐴𝑔 𝐴𝐴𝐶 ℎ

When the ratio of effective height to nominal For 𝑀𝑢 < 𝑀𝑐𝑟 , 𝐼𝑒𝑓𝑓 shall be taken as 0.75𝐼𝑛. For
thickness, ℎ/𝑡, exceeds 30, the factored axial stress
𝑀𝑢 > 𝑀𝑐𝑟, 𝐼𝑒𝑓𝑓 shall be taken as 𝐼𝑐𝑟. 𝑃𝑢/𝑃𝑒 cannot
shall not exceed 0.05𝑓’𝐴𝐴𝐶 .
exceed 1.0.
Factored moment and axial force shall be
11.3.5.5.4 The cracking moment of the wall shall
determined at the midheight of the wall and shall
be calculated using Equation 11-26, where 𝑓𝑟𝐴𝐴𝐶 is
be used for design. The factored moment, 𝑀𝑢, at
given by Section 11.1.8.3:
the midheight of the wall shall be calculated
using 𝑃

SBC 305-CR- 7
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

Equation 11-19. 𝑀𝑐𝑟 = 𝑆𝑛 (𝑓𝑟𝐴𝐴𝐶 + ) Equation 11-26

�
𝑛

SBC 305-CR- 7
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

If the section of AAC masonry contains a

11.3.5.6.2 The deflection, 𝛿𝑠, shall be determined
horizontal leveling bed, the value of 𝑓𝑟𝐴𝐴𝐶 shall
by a second-order analysis that includes the effects
not exceed 345 kPa. of cracking, or by a first-order analysis with the
11.3.5.5.5 The neutral axis for determining the calculated deflections magnified by a factor of 1⁄
cracked moment of inertia, 𝐼𝑐𝑟, shall be determined (1 − 𝑃⁄𝑃𝑒) , where 𝑃𝑒 is determined from
in accordance with the design assumptions of Equation 11-25.
Section 11.3.2. The effects of axial load shall be
11.3.6 Wall design for in-plane loads
permitted to be included when calculating 𝐼𝑐𝑟.
11.3.6.1 Scope — the requirements of Section
Unless stiffness values are obtained by a more
11.3.6 shall apply to the design of walls to resist in-
comprehensive analysis, the cracked moment of
plane loads.
inertia for a solidly grouted wall or a partially
grouted wall with the neutral axis in the face shell 11.3.6.2 Reinforcement — Reinforcement shall be
shall be obtained from Equation 11-27 and Equation in accordance with the following:
11-28.
(a) Reinforcement shall be provided
perpendicular to the shear reinforcement
𝑃𝑢 𝑡𝑠𝑝 Equation 11-27
𝐼𝑐𝑟 ) (𝑑 and shall be at least equal to one-third Av.
= 𝑛 (𝐴𝑠 +
𝑓𝑦 2𝑑 The reinforcement shall be uniformly
𝑏(𝑐)3 distributed and shall not exceed a spacing
)2
−𝑐 + of 2.45 m.
3 (b) The maximum reinforcement ratio shall be
𝐴𝑠𝑓𝑦 + 𝑃𝑢 determined in accordance with Section
𝑐= Equation 11-28 11.3.3.5.
0.57𝑓′ 𝐴 𝑏
11.3.6.3 Flexural and axial strength — The
11.3.5.5.6 The design strength for out-of-plane wall nominal flexural and axial strength shall be
loading shall be in accordance with Equation 11-29. determined in accordance with Section 11.3.4.1.1.
11.3.6.4 Shear strength — The nominal shear
𝑀𝑢 ≤ 𝜙𝑀𝑛 Equation 11-29
strength shall be calculated in accordance with
The nominal moment shall be calculated using Section 11.3.4.1.2.
Equation 11-30 and Equation 11-31 if the reinforcing
11.3.6.5 Flexural cracking strength — The flexural
steel is placed in the center of the wall.
cracking strength shall be calculated in accordance
with Equation 11-33, where 𝑓𝑟𝐴𝐴𝐶 is given by
𝑀 = (𝐴 𝑓
+ 𝑃 ) (𝑑 − 𝑎 ) Equation 11-30 Section 11.1.8.3:
𝑛 𝑠 𝑦 𝑢
2 𝑆𝑛
(𝑃 + 𝐴 𝑓 ) 𝑉 = + 𝑃) Equation 11-33
𝑢
(𝑓
𝑎= 𝑠 𝑦 Equation 11-31 𝑐𝑟 𝑟𝐴𝐴𝐶 𝐴𝑛
′ ℎ
0.85𝑓 𝑏 and 𝛿𝑢 with 𝛿𝑠.
𝐴

11.3.5.6 Deflections — The horizontal midheight

deflection, 𝛿𝑠, under allowable stress design load
combinations shall be limited by the relation:

𝛿𝑠 ≤ 0.007ℎ Equation 11-32

P-delta effects shall be included in deflection

calculation using either Section 11.3.5.6.1 or
Section 11.3.5.6.2.
11.3.5.6.1 For simple support condition top and
bottom, the midheight deflection, 𝛿𝑠, shall be
calculated using either Equation 11-21 or Equation
11-22, as applicable, and replacing 𝑀𝑢 with 𝑀𝑠𝑒𝑟,

SBC 305-CR- 7
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

If the section of AAC masonry

contains a horizontal leveling bed, the
value of 𝑓𝑟𝐴𝐴𝐶 shall not exceed 345
kPa.
11.3.6.6 The maximum
reinforcement requirements of
Section 11.3.3.5 shall not apply if a
shear wall is designed to satisfy the
requirements of Sections 11.3.6.6.1
through 11.3.6.6.4.
11.3.6.6.1 The need for special
boundary elements at the edges of
shear walls shall be evaluated in
accordance with Section 11.3.6.6.2 or
11.3.6.6.3. The requirements of Section
11.3.6.6.4 shall also be satisfied.
11.3.6.6.2 This Section applies to walls
bending in single curvature in which
the flexural limit state response is
governed by yielding at the base of the

SBC 305-CR- 7
 CHAPTER 11—STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC)

wall. Walls not satisfying those requirements shall unless the special boundary element
be designed in accordance with Section 11.3.6.6.3. terminates on a footing or mat, where
(a) Special boundary elements shall be special boundary element transverse
provided over portions of compression reinforcement shall extend at least 300
zones where: mm into the footing or mat.
(d) Horizontal shear reinforcement in the wall
𝑙𝑤 web shall be anchored to develop the
𝑐≥ Equation 11-34
600(𝐶𝑑 𝛿𝑛𝑒/ℎ𝑤) specified yield strength, fy, within the
confined core of the boundary element.
and 𝑐 is calculated for the 𝑃𝑢 given by SBC 301
Load Combination 5 (1.2𝐷 + 1.0𝐸 + 𝐿 + 0.2𝑆),
and the corresponding nominal moment strength,
𝑀𝑛, at the base critical section. The load factor on
𝐿 in Load Combination 5 is reducible to 0.5, as per
exceptions to Section 2.3.2 of SBC 301.
(b) Where special boundary elements are
required by Section 11.3.6.6.2 (a), the
special boundary element reinforcement
shall extend vertically from the critical
section a distance not less than the larger
of lw, or Mu/4Vu.
11.3.6.6.3 Shear walls not designed to the
provisions of Section 11.3.6.6.2 shall have special
9.3.6.5.4. boundary elements at boundaries and
edges around openings in shear walls where the
maximum extreme fiber compressive stress,
corresponding to factored forces including
earthquake effect, exceeds 0.2𝑓′ . The special
𝐴
boundary element shall be permitted to be
discontinued where the calculated compressive
stress is less than 0.15𝑓′ . Stresses shall be
𝐴
calculated for the factored forces using a linearly
elastic model and gross section properties. For
walls with flanges, an effective flange width as
defined in Section 5.1.1.2.3 shall be used.
11.3.6.6.4 Where special boundary elements are
required by Section 11.3.6.6.2 or 11.3.6.6.3,
9.3.6.5.5(a) through (d) shall be satisfied and tests
shall be performed to verify the strain capacity of
the element:
(a) The special boundary element shall extend
horizontally from the extreme
compression fiber a distance not less than
the larger of (c − 0.1lw) and c/2.
(b) In flanged sections, the special boundary
element shall include the effective flange
width in compression and shall extend at
least 300 mm into the web.
(c) Special boundary element transverse
reinforcement at the wall base shall extend
into the support at least the development
length of the largest longitudinal
reinforcement in the boundary element

SBC 305-CR- 7
PART 4—PRESCRIPTIVE DESIGN

PART 4—PRESCRIPTIVE DESIGN METHOD

SBC 305-CR- 7
 CHAPTER 12—

CHAPTER 12—VENEER

12.1 —General
12.1.6 General design requirements
12.1.6.1 Design and detail the backing system of
12.1.1 Scope exterior veneer to resist water penetration. Exterior
This chapter provides requirements for design and sheathing shall be covered with a water-resistant
detailing of anchored masonry veneer and adhered membrane, unless the sheathing is water resistant
masonry veneer. and the joints are sealed.
12.1.1.1 The provisions of Part 1, excluding 12.1.6.2 Design and detail flashing and weep holes
Sections 1.2.1(c) and 1.2.2; Chapter 4, excluding in exterior veneer wall systems to resist water
Sections 4.1 and 4.3, and Chapter 6 shall apply to penetration into the building interior. Weep holes
design of anchored and adhered veneer except as shall be at least 5 mm in diameter and spaced less
specifically stated in this Chapter. than 800 mm on center.
12.1.1.2 Section 4.5 shall not apply to adhered 12.1.6.3 Design and detail the veneer to
veneer. accommodate differential movement.
12.1.1.3 Articles 1.4 A and B and 3.4 C of TMS 12.2 —Anchored veneer
602/ACI 530.1/ASCE 6 shall not apply to any
veneer. Articles 3.4 B and F shall not apply to 12.2.1 Alternative design of anchored masonry
anchored veneer. Articles 3.3 B and 3.4 A, B, E veneer
and F shall not apply to adhered veneer. The alternative design of anchored veneer, which
is permitted under Section 1.3, shall satisfy the
12.1.2 Design of anchored veneer
following conditions:
Anchored veneer shall meet the requirements of
(a) Loads shall be distributed through the
Section 12.1.6 and shall be designed rationally by
veneer to the anchors and the backing
Section 12.2.1 or detailed by the prescriptive
using principles of mechanics.
requirements of Section 12.2.2.
(b) Out-of-plane deflection of the backing
12.1.3 Design of adhered veneer shall be limited to maintain veneer
stability.
Adhered veneer shall meet the requirements of
(c) The veneer is not subject to the flexural
Section 12.1.6, and shall be designed rationally by
tensile stress provisions of Section 8.2 or
Section 12.3.1 or detailed by the prescriptive
the nominal flexural tensile strength
requirements of Section 12.3.2.
provisions of Section 9.1.9.2.
12.1.4 Dimension stone (d) The provisions of Section 12.1, Section
12.2.2.9, and Section 12.2.2.10 shall apply.
The provisions of Sections 12.1.1, 12.1.3 and 12.3
shall apply to design of adhered dimension stone 12.2.2 Prescriptive requirements for anchored
veneer. Anchored dimension stone veneer is not masonry veneer
addressed by this Code. Such a veneer system
12.2.2.1 Except as provided in Section 12.2.2.11,
shall be considered a Special System, and
prescriptive requirements for anchored masonry
consideration for approval of its use shall be
veneer shall not be used in areas where the
submitted to the Building Official.
velocity pressure, 𝑞𝑧, exceeds 1.92 kPa as given in
12.1.5 Autoclaved aerated concrete masonry SBC 301.
veneer Autoclaved aerated concrete masonry as a 12.2.2.2 Connect anchored veneer to the backing
veneer wythe is not addressed by this Chapter. with anchors that comply with Section 12.2.2.5 and
Such a veneer system shall be considered a Special Article 2.4 of TMS 602/ACI 530.1/ASCE 6.
System, and consideration for approval of its use
shall be submitted to the Building Official. 12.2.2.3 Vertical support of anchored masonry
veneer

SBC 305-CR- 7
 CHAPTER 12—

12.2.2.3.1 The weight of anchored veneer shall be (a) have corrugations as given in Section
supported vertically on concrete or masonry 12.2.2.5.1.1, or
foundations or other noncombustible structural (b) be bent, notched, or punched to provide
construction, except as permitted in Section equivalent performance in pull-out or
12.2.2.3.1.1. push- through.
12.2.2.3.1.1 If anchored veneer with a backing of 12.2.2.5.2.2 Sheet-metal anchors shall be placed as
cold-formed steel framing exceeds 9.15 m, or follows:
11.60 m at a gable, in height above the location
where the veneer is supported, the weight of the (a) With solid units, embed anchors in the
veneer shall be supported by noncombustible mortar joint and extend into the veneer a
construction at each story above 9.15 m in height minimum of 38.0 mm, with at least 16.0
mm mortar cover to the outside face.
12.2.2.3.1.2 When anchored veneer is used as an (b) With hollow units, embed anchors in
interior finish on wood framing, it shall have a mortar or grout and extend into the veneer
weight of 195 kg/m2 or less and be installed in a minimum of 38.0 mm, with at least 16.0
conformance with the provisions of this Chapter. mm mortar or grout cover to the outside
12.2.2.3.2 When anchored veneer is supported by face.
floor construction, the floor shall be designed to 12.2.2.5.3 Wire anchors
limit deflection as required in Section 5.2.1.4.1.
12.2.2.5.3.1 Wire anchors shall be at least wire
12.2.2.3.3 Provide noncombustible lintels or size WD 4.0 and have ends bent to form an
supports attached to noncombustible framing over extension from the bend at least 50.0 mm long.
openings where the anchored veneer is not self- Wire anchors shall be without drips.
supporting. Lintels shall have a length of bearing
not less than 100 mm. The deflection of such 12.2.2.5.3.2 Wire anchors shall be placed as
lintels or supports shall conform to the follows:
requirements of Section 5.2.1.4.1. (a) With solid units, embed anchors in the
12.2.2.4 Masonry units — Masonry units shall be mortar joint and extend into the veneer a
at least 67 mm in actual thickness. minimum of 38.0 mm, with at least 16.0
mm mortar cover to the outside face.
12.2.2.5 Anchor requirements (b) With hollow units, embed anchors in
12.2.2.5.1 Corrugated sheet-metal anchors mortar or grout and extend into the veneer
a minimum of 38.0 mm, with at least 16.0
12.2.2.5.1.1 Corrugated sheet-metal anchors shall mm mortar or grout cover to the outside
be at least 22 mm wide, have a base metal face.
thickness of at least 0.8 mm, and shall have
corrugations with a wavelength of 7.6 to 12.70 mm 12.2.2.5.4 Joint reinforcement
and an amplitude of 1.5 to 2.5 mm. 12.2.2.5.4.1 Ladder-type or tab-type joint
12.2.2.5.1.2 Corrugated sheet-metal anchors shall reinforcement is permitted. Cross wires used to
be placed as follows: anchor masonry veneer shall be at least wire size
WD 4.0 and shall be spaced at a maximum of 400
(a) With solid units, embed anchors in the mm on center. Cross wires shall be welded to
mortar joint and extend into the veneer a longitudinal wires, which shall be at least wire size
minimum of 38.0 mm, with at least 16-mm WD 4.0. Cross wires and taps shall be without
mortar cover to the outside face. drips
(b) With hollow units, embed anchors in
mortar or grout and extend into the veneer 12.2.2.5.4.2 Embed longitudinal wires of joint
a minimum of 38.0 mm, with at least 16- reinforcement in the mortar joint with at least 16.0
mm mortar or grout cover to the outside mm mortar cover on each side.
face. 12.2.2.5.5 Adjustable anchors
12.2.2.5.2 Sheet-metal anchors 12.2.2.5.5.1 Sheet-metal and wire components of
12.2.2.5.2.1 Sheet-metal anchors shall be at least adjustable anchors shall conform to the
22.0 mm wide, shall have a base metal thickness requirements of Section 12.2.2.5.2 or 12.2.2.5.3.
of at least 1.5 mm, and shall: Adjustable anchors with joint reinforcement shall
also meet the requirements of Section 12.2.2.5.4.

SBC 305-CR- 7
 CHAPTER 12—

12.2.2.5.5.2 Maximum clearance between 12.2.2.8 Masonry veneer anchored to masonry or

connecting parts of the tie shall be 1.6 mm. concrete backing
12.2.2.5.5.3 Adjustable anchors shall be detailed to 12.2.2.8.1 Attach veneer to masonry backing with
prevent disengagement. wire anchors, adjustable anchors, or joint
12.2.2.5.5.4 Pintle anchors shall have one or more reinforcement. Attach veneer to concrete backing
pintle legs of wire size WD 5.0 and shall have an with adjustable anchors.
offset not exceeding 32.0 mm. 12.2.2.8.2 A 115 mm maximum distance between
12.2.2.5.5.5 Adjustable anchors of equivalent the inside face of the veneer and the outside face
strength and stiffness to those specified in Sections of the masonry or concrete backing shall be
12.2.2.5.5.1 through 12.2.2.5.5.4 are permitted. specified. A 25.0 mm minimum air space shall be
specified.
12.2.2.5.6 Anchor spacing
12.2.2.9 Veneer not laid in running bond —
12.2.2.5.6.1 For adjustable two-piece anchors, Anchored veneer not laid in running bond shall
anchors of wire size WD 4.0, and 0.8 mm have joint reinforcement of at least one wire, of
corrugated sheet-metal anchors, provide at least size WD 4.0, spaced at a maximum of 450 mm on
one anchor for each 0.25 m2 of wall area. center vertically.
12.2.2.5.6.2 For other anchors, provide at least one 12.2.2.10 Requirements in seismic areas
anchor for each 0.33 m2 of wall area.
12.2.2.10.1 Seismic Design Category C
12.2.2.5.6.3 Space anchors at a maximum of 800
mm horizontally and 625 mm vertically, but not to 12.2.2.10.1.1 The requirements of this section
exceed the applicable requirements of Section apply to anchored veneer for buildings in Seismic
12.2.2.5.6.1 or 12.2.2.5.6.2. Design Category C.
12.2.2.5.6.4 Provide additional anchors around 12.2.2.10.1.2 Isolate the sides and top of anchored
openings larger than 400 mm in either dimension. veneer from the structure so that vertical and
Space anchors around perimeter of opening at a lateral seismic forces resisted by the structure are
maximum of 0.90 m on center. Place anchors not imparted to the veneer.
within 300 mm of openings. 12.2.2.10.2 Seismic Design Category D
12.2.2.5.7 Joint thickness for anchors — Mortar 12.2.2.10.2.1 The requirements for Seismic Design
bed joint thickness shall be at least twice the Category C and the requirements of this section
thickness of the embedded anchor. apply to anchored veneer for buildings in Seismic
12.2.2.6 Masonry veneer anchored to wood Design Category D.
backing is not a common construction practice in 12.2.2.10.2.2 Reduce the maximum wall area
the Kingdom of Saudi Arabia nor in other GCC supported by each anchor to 75 percent of that
countries. required in Sections 12.2.2.5.6.1 and 12.2.2.5.6.2.
12.2.2.7 Masonry veneer anchored to steel backing Maximum horizontal and vertical spacings are
unchanged.
12.2.2.7.1 Attach veneer with adjustable anchors.
12.2.2.11 Requirements in areas of high winds —
12.2.2.7.2 Attach each anchor to steel framing The following requirements apply in areas where
with at least a No.10 corrosion-resistant screw the velocity pressure, 𝑞𝑧 exceeds 1.92 kPa but does
(nominal shank diameter of 5 mm, or with a not exceed 2.63 kPa and the building's mean roof
fastener having equivalent or greater pullout height is less than or equal to 18.3 m:
strength.
(a) Reduce the maximum wall area supported
12.2.2.7.3 Cold-formed steel framing shall be by each anchor to 70 percent of that
corrosion resistant and have a minimum base required in Sections 12.2.2.5.6.1 and
metal thickness of 1.0 mm. 12.2.2.5.6.2.
12.2.2.7.4 A 115-mm maximum distance between (b) Space anchors at a maximum 450 mm
the inside face of the veneer and the steel framing horizontally and vertically.
shall be specified. A 25.0 mm minimum air space (c) Provide additional anchors around
shall be specified. openings larger than 400 mm in either
direction. Space anchors around perimeter
of opening at a maximum of 600 mm on

SBC 305-CR- 8
 CHAPTER 12—

center. Place anchors within 300 mm of 12.3.2 Prescriptive requirements for adhered
openings. masonry veneer
12.2.2.11.1 Provide continuous single wire joint 12.3.2.1 Unit sizes — Adhered veneer units shall
reinforcement of wire size MW11 at a maximum not exceed 66.0 mm in specified thickness, 900
spacing of 450 mm on center vertically. mm in any face dimension, nor more than 0.46 m2
Mechanically attach anchors to the joint in total face area, and shall not weigh more
reinforcement with clips or hooks. Corrugated
than 73 kg/m2.
sheet metal anchors shall not be used.
12.3.2.2 Wall area limitations — The height,
12.3 —Adhered veneer length, and area of adhered veneer shall not be
12.3.1 Alternative design of adhered masonry limited except as required to control restrained
veneer differential movement stresses between veneer and
backing.
The alternative design of adhered veneer, which is
permitted under Section 1.3, shall satisfy the 12.3.2.3 Backing — Backing shall provide a
following conditions: continuous, moisture-resistant surface to receive the
adhered veneer. Backing is permitted to be
(a) Loads shall be distributed through the masonry, concrete, or metal lath and Portland
veneer to the backing using principles of cement plaster applied to masonry, concrete, steel
mechanics. framing, or wood framing.
(b) Out-of-plane curvature shall be limited to
prevent veneer unit separation from the 12.3.2.4 Adhesion developed between adhered
backing. veneer units and backing shall have a shear
(c) The veneer is not subject to the flexural strength of at least 345 kPa based on gross unit
tensile stress provisions of Section 8.2 or surface area when tested in accordance with
the nominal flexural tensile strength ASTM C482, or shall be adhered in compliance
provisions of Section 9.1.9.2. with Article 3.3 C of TMS 602/ ACI 530.1/ASCE
(d) The provisions of Section 12.1 shall apply. 6.

SBC 305-CR- 8
 CHAPTER 13—GLASS UNIT

CHAPTER 13—GLASS UNIT MASONRY

13.1 —General
individual standard-unit panel shall be
23.22 m2 and the maximum area of each thin-
13.1.1 Scope unit panel shall be 13.94 m2. The maximum
This chapter provides requirements for empirical dimension between structural supports shall be
design of glass unit masonry as non-load-bearing 7.60 m wide or 6.10 m high.
elements in exterior or interior walls. 13.2.3.2 When the factored wind pressure exceeds
13.1.1.1 The provisions of Part 1 and Part 2, 768 Pa, standard-unit panels shall be designed in
excluding Sections 1.2.1(c), 1.2.2, 4.1, 4.2, and 4.3, accordance with Section 13.2.1 and thin-unit panels
shall apply to design of glass unit masonry, except shall be designed in accordance with Section 13.2.2.
as stated in this Chapter.
13.2.4 Curved panels
13.1.1.2 Article 1.4 of TMS 602/ACI 530.1/ASCE
The width of curved panels shall conform to the
6 shall not apply to glass unit masonry.
requirements of Sections 13.2.1, 13.2.2, and 13.2.3,
13.1.2 General design requirements except additional structural supports shall be
provided at locations where a curved section joins
Design and detail glass unit masonry to a straight section and at inflection points in multi-
accommodate differential movement. curved walls.
13.1.3 Units 13.3 —Support
13.1.3.1 Hollow or solid glass block units shall be
standard or thin units.
13.3.1 General requirements
Glass unit masonry panels shall be isolated so that
13.1.3.2 The specified thickness of standard units
in-plane loads are not imparted to the panel.
shall be at least 98 mm.
13.1.3.3 The specified thickness of thin units shall 13.3.2 Vertical
be 80 mm for hollow units or 75 mm for solid 13.3.2.1 Maximum total deflection of structural
units. members supporting glass unit masonry shall not
exceed 𝑙/600.
13.2 —Panel size
13.3.3 Lateral
13.2.1 Exterior standard-unit panels
13.3.3.1 Glass unit masonry panels, more than one
The maximum area of each individual standard-
unit wide or one unit high, shall be laterally
unit panel shall be based on the design wind
supported along the top and sides of the panel.
pressure, in accordance with Figure 13.1. The
Lateral support shall be provided by panel anchors
maximum dimension between structural supports
along the top and sides spaced not more than 400
shall be 7.6 m horizontally or 6.10 m vertically.
mm on center or by channel-type restraints. Glass
13.2.2 Exterior thin-unit panels unit masonry panels shall be recessed at least 25.0
mm within channels and chases. Channel-type
The maximum area of each individual thin-unit
restraints must be oversized to accommodate
panel shall be 9.29 m2. The maximum dimension
expansion material in the opening, and packing
between structural supports shall be 4.50 m wide
and sealant between the framing restraints and the
or
glass unit masonry perimeter units. Lateral
3.0 m high. Thin units shall not be used in
supports for glass unit masonry panels shall be
applications where the factored design wind
designed to resist applied loads, or a minimum of
pressure per SBC 301 exceeds 1,500 Pa.
3000 N/m of panel, whichever is greater.
13.2.3 Interior panels 13.3.3.2 Glass unit masonry panels that are no
13.2.3.1 When the factored wind pressure more than one unit wide shall conform to
does not exceed 768 Pa, the maximum area of the
each

SBC 305-CR- 8
 CHAPTER 13—GLASS UNIT

requirements of Section 13.3.3.1, except that lateral

support at the top of the panel is not required.
13.3.3.3 Glass unit masonry panels that are no
more than one unit high shall conform to the
requirements of Section 13.3.3.1, except that lateral
support at the sides of the panels is not required.
13.3.3.4 Glass unit masonry panels that are a
single glass masonry unit shall conform to the
requirements of Section 13.3.3.1, except that lateral
support shall not be provided by panel anchors.
13.4 —Expansion joints
Glass unit masonry panels shall be provided with
expansion joints along the top and sides at
structural supports. Expansion joints shall have
sufficient thickness to accommodate displacements
of the supporting structure, but shall not be less
than 10 mm in thickness. Expansion joints shall be
entirely free of mortar or other debris and shall be
filled with resilient material.
13.5 —Base surface treatment
The surface on which glass unit masonry panels
are placed shall be coated with a water-based
asphaltic emulsion or other elastic waterproofing
material prior to laying the first course.
13.6 —Mortar
Glass unit masonry shall be laid with Type S or N
mortar.
13.7 —Reinforcement
Glass unit masonry panels shall have horizontal
joint reinforcement spaced not more than 400 mm
on center, located in the mortar bed joint, and
extending the entire length of the panel but not
across expansion joints. Longitudinal wires shall
be lapped a minimum of 150 mm at splices. Joint
reinforcement shall be placed in the bed joint
immediately below and above openings in the
panel. The reinforcement shall have at least two
parallel longitudinal wires of size WD 4.0 and
have welded cross wires of size WD 4.0.

SBC 305-CR- 8
CHAPTER 13—GLASS UNIT

TABLES AND FIGURES OF CHAPTER 13

Figure 13.1: Factored design wind pressure for glass unit masonry

SBC 305-CR- 8
 CHAPTER 14—MASONRY PARTITION

CHAPTER 14—MASONRY PARTITION WALLS

14.1 —General partition walls resisting service level unfactored

14.1.1 Scope lateral loads that exceed 0.240 kPa when using
Table 14.1 or 0.48 kPa when using
This chapter provides requirements for the design
of masonry partition walls. 14.2.3.3 Table 14.2.

14.1.2 Design of partition walls 14.2.3.4 Seismic Design Category — the

prescriptive design requirements of Chapter 14
Partition walls shall be designed by one of the shall not apply to the design of masonry partition
following: walls in Seismic Design Category D.
(a) The prescriptive design requirements of 14.2.3.5 Nonparticipating Elements — Partition
Section 14.2 through 14.5, or walls designed using the prescriptive requirements
(b) The requirements of Part 1, Part 2 and the of Chapter 14 shall be designed as
requirements of Chapter 8, Chapter 9, 'nonparticipating elements' in accordance with the
Chapter 11, or Chapter 13. requirements of Section 7.3.1.
14.2 —Prescriptive design of partition 14.2.3.6 Enclosed Buildings — The prescriptive
walls design requirements of Chapter 14 shall only be
permitted to be applied to the design of masonry
14.2.1 General partition walls in Enclosed Buildings as defined by
14.2.1.1 The provisions of Part 1 and Part 2, SBC 301
excluding Sections 1.2.1(c), 1.2.2, 4.1, 4.2, and 4.3,
14.2.3.7 Risk Category IV — The prescriptive
shall apply to prescriptive design of masonry
design requirements of Chapter 14 shall not apply
partition walls.
to the design of masonry partition walls in Risk
14.2.1.2 Article 1.4 of TMS 602/AC1 530.1/ Category IV as defined in SBC 301.
ASCE 6 shall not apply to prescriptively designed
14.2.3.8 Masonry not laid in running bond — The
masonry partition walls.
prescriptive design requirements of Chapter 14
14.2.2 Thickness Limitations shall not apply to the design of masonry not laid in
running bond in horizontally spanning walls.
14.2.2.1 Minimum thickness — The minimum
nominal thickness of partition walls shall be 100 14.2.3.9 Glass unit masonry — The prescriptive
mm. design requirements of Chapter 14 shall not apply
to the design of glass unit masonry.
14.2.2.2 Maximum thickness — The maximum
nominal thickness of partition walls shall be 300 14.2.3.10 AAC masonry — The prescriptive
mm. design requirements of Chapter 14 shall not apply
to the design of AAC masonry.
14.2.3 Limitations
14.2.3.11 Concrete masonry — Concrete masonry,
14.2.3.1 Vertical loads — The prescriptive design designed in accordance with Chapter 14, shall
requirements of Chapter 14 shall not apply to the comply with one of the following:
design of partition walls that support vertical
compressive, service loads of more than 2900 N/m (a) The minimum normalized web area of
in addition to their own weight. The resultant of concrete masonry units, determined in
vertical loads shall be placed within the center accordance with ASTM C140, shall not be
third of the wall thickness. The prescriptive design less than 187,500 mm2/m2, or
requirements of Chapter 14 shall not apply to the (b) The member shall be grouted solid.
design of partition walls that resist net axial 14.2.3.12 Support — The provisions of Chapter 14
tension. shall not apply to masonry vertically supported on
14.2.3.2 Lateral loads — The prescriptive design wood construction.
requirements of Chapter 14 shall not apply to

SBC 305-CR- 8
 CHAPTER 14—MASONRY PARTITION

14.3 —Lateral support The ratio of height-to-nominal-thickness for

14.3.1 Maximum 𝑙/𝑡 and ℎ/𝑡 cantilevered partition walls shall not exceed 6 for
solid masonry or 4 for hollow masonry.
Masonry partition walls without openings shall be
laterally supported in either the horizontal or the 14.3.4 Support elements
vertical direction so that 𝑙/𝑡 or ℎ/𝑡 does not exceed Lateral support shall be provided by cross walls,
the values given in Table 14.1or pilasters, or structural frame members when the
Table 14.2. It shall not be permitted to decrease the limiting distance is taken horizontally; or by
cross-section of the partition wall between floors, roofs acting as diaphragms, or structural
supports unless permitted by Section 14.3.2. frame members when the limiting distance is taken
vertically.
14.3.2 Openings
14.4 —Anchorage
Masonry partition walls with single or multiple
openings shall be laterally supported in either the 14.4.1 General
horizontal or vertical direction so that 1/𝑡 or ℎ/𝑡 Masonry partition walls shall be anchored in
does not exceed the values given in Table 14.1 or accordance with this section.
Table 14.2 divided by √𝑊𝑇⁄𝑊𝑆. 14.4.2 Intersecting walls
𝑊𝑆 is the dimension of the structural wall strip Masonry partition walls depending upon one
measured perpendicular to the span of the wall another for lateral support shall be anchored or
strip and perpendicular to the thickness as shown bonded at locations where they meet or intersect
in Table 14.1. 𝑊𝑆 is measured from the edge of by one of the following methods:
the opening. 𝑊𝑆 shall be no less than 3𝑡 on each
14.4.2.1 Fifty percent of the units at the
side of each opening. Therefore, at walls with
intersection shall be laid in an overlapping
multiple openings, jambs shall be no less than 6𝑡
between openings. For design purposes, the masonry bonding pattern, with alternate units
effective 𝑊𝑆 shall not be assumed to be greater having a bearing of at least 75.0 mm on the unit
than 6𝑡. At non- masonry lintels, the edge of the below.
opening shall be considered the edge of the non- 14.4.2.2 Walls shall be anchored at their
masonry lintel. 𝑊𝑆 shall occur uninterrupted over intersection at vertical intervals of not more than
the full span of the wall. 400 mm with joint reinforcement or 6.4 mm mesh
galvanized hardware cloth.
𝑊𝑇 is the dimension, parallel to 𝑊𝑆, from the
center of the opening to the opposite end of 𝑊𝑆 as 14.4.2.3 Other metal ties, joint reinforcement or
shown in Table 14.1. anchors, if used, shall be spaced to provide
Where there are multiple openings perpendicular to equivalent area of anchorage to that required by
Section 14.4.2.2.
𝑊𝑆, 𝑊𝑇 shall be measured from the center of a
virtual opening that encompasses such openings. 14.5 —Miscellaneous requirements
Masonry elements within the virtual opening must
be designed in accordance with Chapter 8 or 14.5.1 Chases and recesses
Chapter 9. Masonry directly above chases or recesses wider
For walls with openings that span no more than than 300 mm shall be supported on lintels.
1200 mm, parallel to 𝑊𝑆, if 𝑊𝑆 is no less than 14.5.2 Lintels
1200 mm, then it shall be permitted to ignore the
effect of those openings. The design of masonry lintels shall be in
accordance with the provisions of Section 5.2.
The span of openings, parallel to 𝑊𝑆, shall be
limited so that the span divided by 𝑡 does not 14.5.3 Lap splices
exceed the values given in Table 14.1or Lap splices for bar reinforcement or joint
Table 14.2. reinforcement, required by Section 7.4.3.1 and
located in masonry partition walls designed in
14.3.3 Cantilever walls accordance with this Chapter, shall be a minimum
of 48𝑑𝑏.

SBC 305-CR- 8
 CHAPTER 14—MASONRY PARTITION

TABLES AND FIGURES OF CHAPTER 14

Table 14.1: Maximum 𝐥/𝐭𝟏 or 𝐡/𝐭𝟏 for 0.240 kPa lateral load.𝟐

Unit and Masonry Type Mortar types

Portland cement/lime or mortar Masonry cement or air
cement entrained portland cement/lime
M or S N M or S N
3
Ungrouted and partially grouted hollow units. 26 24 22 18
3
Solid units and fully grouted hollow units. 40 36 33 26
1
𝑡 by definition is the nominal thickness of member
2
See Section 14.2.3.2.
3
For non-cantilevered walls laterally supported at both ends. See Section 14.3.3 for cantilevered walls.

Table 14.2: Maximum 𝐥/𝐭𝟏 or 𝐡/𝐭𝟏 for 0.480 kPa lateral load.𝟐

Unit and Masonry Type Mortar types

Portland cement/lime or mortar Masonry cement or air
cement entrained portland cement/lime
M or S N M or S N
3
Ungrouted and partially grouted hollow units. 18 16 14 12
3
Solid units and fully grouted hollow units. 28 24 22 18
1
𝑡 by definition is the nominal thickness of member
2
See Section 14.2.3.2.
3
For non-cantilevered walls laterally supported at both ends. See Section 14.3.3 for cantilevered walls

Figure 14.1: Graphical representation of 𝑊𝑆 and 𝑊𝑇

SBC 305-CR- 8
PART 5—

PART 5—APPENDICES

SBC 305-CR- 8
 APPENDIX A—EMPIRICAL DESIGN OF

APPENDIX A—EMPIRICAL DESIGN OF MASONRY

A.1—General A.1.2.8 Concrete masonry — Concrete masonry,

A.1.1 Scope designed in accordance with APPENDIX A, shall
comply with one of the following:
This appendix provides requirements for empirical
design of masonry. (a) The minimum normalized web area of
concrete masonry units, determined in
A.1.1.1 The provisions of Part 1 and Part 2, accordance with ASTM C140, shall not be
excluding Part 1 Sections 1.2.1(c), 1.2.2, 4.1, 4.2 less than 187,500 mm2/m2, or
and 4.3, shall apply to empirical design, except as (b) The member shall be grouted solid.
specifically stated in this Chapter.
A.1.2.9 Support — The provisions of Appendix A
A.1.1.2 Article 1.4 of TMS 602/ACI 530.1/ASCE shall not apply to masonry vertically supported on
6 shall not apply to empirically designed masonry. wood construction.
A.1.2 Limitations A.1.2.10 Partition walls — The provisions of
A.1.2.1 Gravity Loads — The resultant of gravity Appendix A shall not apply to partition walls.
loads shall be placed within the center third of the A.2—Height
wall thickness and within the central area bounded
by lines at one-third of each cross-sectional Buildings relying on masonry walls as part of their
dimension of foundation piers. lateral-force-resisting system shall not exceed 10.70
m in height.
A.1.2.2 Seismic — Empirical requirements shall
not apply to the design of masonry for buildings, A.3—Lateral stability
parts of buildings or other structures in Seismic
A.3.1 Shear walls
Design Category D as defined in SBC 301, and
shall not apply to the design of the seismic-force- Where the structure depends upon masonry walls
resisting system for structures in Seismic Design for lateral stability, shear walls shall be provided
Categories B or C. parallel to the direction of the lateral forces resisted.
A.1.2.3 Wind — Empirical requirements shall be A.3.1.1 In each direction in which shear walls are
permitted to be applied to the design of masonry required for lateral stability, shear walls shall be
elements defined by Table A.1, based on building positioned in at least two separate planes parallel
height and basic wind speed that are applicable to with the direction of the lateral force. The
the building. minimum cumulative length of shear walls
provided along each plane shall be 0.2 multiplied
A.1.2.4 Buildings and other structures in Risk
by the long dimension of the building. Cumulative
Category IV — Empirical requirements shall not
length of shear walls shall not include openings or
apply to the design of masonry for buildings, parts
any element whose length is less than one-half its
of buildings or other structures in Risk Category
height.
IV as defined in SBC 301.
A.3.2 Shear walls shall be spaced so that the
A.1.2.5 Other horizontal loads — Empirical
length-to-width ratio of each diaphragm
requirements shall not apply to structures resisting
transferring lateral forces to the shear walls does
horizontal loads other than permitted wind or
not exceed values given in Table A.3.
seismic loads or foundation walls as provided in
Section A.6.3. A.3.3 Roofs
A.1.2.6 Glass unit masonry — The provisions of The roof construction shall be designed so as not
APPENDIX A shall not apply to glass unit masonry. to impart out-of-plane lateral thrust to the walls
under roof gravity load.
A.1.2.7 AAC masonry — The provisions of
APPENDIX A shall not apply to AAC masonry. A.4—Compressive stress requirements

SBC 305-CR- 8
 APPENDIX A—EMPIRICAL DESIGN OF

A.4.1 Calculations in Figure A.2. Where there are multiple openings

Dead loads and live loads shall be in accordance perpendicular to 𝑊𝑆, 𝑊𝑇 shall be measured from
with SBC 301, with such live load reductions as the center of a virtual opening that encompasses
are permitted in SBC 301. Compressive stresses in such
masonry due to vertical dead plus live loads openings. Masonry elements within the virtual
(excluding wind or seismic loads) shall be opening must be designed in accordance with
determined in accordance with the following: Chapter 8 or Chapter 9.
(a) Stresses shall be calculated based on For walls with openings that span no more than
specified dimensions. 1200 mm, parallel to 𝑊𝑆, if 𝑊𝑆 is no less than
(b) Calculated compressive stresses for single 1200 mm, then it shall be permitted to ignore the
wythe walls and for multiwythe composite effect of those openings.
masonry walls shall be determined by The span of openings, parallel to 𝑊𝑆, shall be
dividing the design load by the gross limited so that the span divided by 𝑡 does not
cross- sectional area of the member. The exceed the values given in Table A.5.
area of openings, chases, or recesses in
walls shall not be included in the gross In addition to these limitations, lintels shall be
cross-sectional area of the wall. designed for gravity loads in accordance with
Section A.9.2.
A.4.2 Allowable compressive stresses
In calculating the ratio for multiwythe walls, use
The compressive stresses in masonry shall not the following thickness:
exceed the values given in Table A.4. In
multiwythe walls, the allowable stresses shall be (1) The nominal wall thicknesses for solid
based on the weakest combination of the units and walls and for hollow walls bonded with
mortar used in each wythe. masonry headers (Section A.7.2).
(2) The sum of the nominal thicknesses of the
A.5—Lateral support
wythes for non-composite walls
A.5.1 Maximum 𝑙/𝑡 and ℎ/𝑡 connected with wall ties (Section A.7.3).
Masonry walls without openings shall be laterally A.5.2 Cantilever walls
supported in either the horizontal or the vertical
Except for parapets, the ratio of height-to-nominal
direction so that 𝑙/𝑡 or ℎ/𝑡 does not exceed the
thickness for cantilever walls shall not exceed 6
values given in Table A.5.
for solid masonry or 4 for hollow masonry. For
Masonry walls with single or multiple openings parapets see Section A.6.4.
shall be laterally supported in either the horizontal
A.5.3 Support elements
or vertical direction so that 𝑙/𝑡 or ℎ/𝑡 does not
exceed the values given in Table A.5 divided by Lateral support shall be provided by cross walls,
√𝑊𝑇⁄𝑊𝑆 pilasters, or structural frame members when the
limiting distance is taken horizontally; or by
𝑊𝑆 is the dimension of the structural wall strip floors, roofs acting as diaphragms, or structural
measured perpendicular to the span of the wall frame members when the limiting distance is taken
strip and perpendicular to the thickness as shown vertically.
in Figure A.2. 𝑊𝑆 is measured from the edge of the
opening. 𝑊𝑆 shall be no less than 3𝑡 on each side A.6—THICKNESS OF MASONRY
of each opening. Therefore, at walls with multiple A.6.1 General
openings, jambs shall be no less than 6𝑡 between
openings. For design purposes, the effective 𝑊𝑆 Minimum thickness requirements shall be based
shall not be assumed to be greater than 6𝑡. At non- on nominal dimensions of masonry.
masonry lintels, the edge of the opening shall be A.6.2 Minimum thickness
considered the edge of the non-masonry lintel. 𝑊𝑆
shall occur uninterrupted over the full span of the A.6.2.1 Load-bearing walls — The minimum
wall. thickness of load-bearing walls of one story
buildings shall be 150 mm. The minimum
𝑊𝑇 is the dimension, parallel to 𝑊𝑆, from the thickness of load-bearing walls of buildings more
center of the opening to the opposite end of 𝑊𝑆 as than one story high shall be 200 mm.
shown

SBC 305-CR- 9
 APPENDIX A—EMPIRICAL DESIGN OF

A.6.2.2 Rubble stone walls — The minimum (a) Length, measured perpendicular to its
thickness of rough, random, or coursed rubble thickness, shall not exceed 3 times its
stone walls shall be 400 mm. thickness.
A.6.2.3 Shear walls — The minimum thickness of (b) Height shall be equal to or less than 4
masonry shear walls shall be 200 mm. times its thickness.
A.6.2.4 Foundation walls — The minimum A.7—Bond
thickness of foundation walls shall be 200 mm. A.7.1 General
A.6.2.5 Foundation piers — The minimum Wythes of multiple wythe masonry walls shall be
thickness of foundation piers shall be 200 mm. bonded in accordance with the requirements of
A.6.2.6 Parapet walls — The minimum thickness Section A.7.2, Section A.7.3, or Section A.7.4.
of parapet walls shall be 200 mm. A.7.2 Bonding with masonry headers
A.6.2.7 Partition walls — The minimum thickness A.7.2.1 Solid units — Where adjacent wythes of
of partition walls shall be 100 mm. solid masonry walls are bonded by means of
A.6.2.8 Change in thickness — Where walls of masonry headers, no less than 4 percent of the wall
masonry of hollow units or masonry bonded surface area of each face shall be composed of
hollow walls are decreased in thickness, a course headers extending not less than 75 mm into each
or courses of solid masonry units or fully grouted wythe. The distance between adjacent full-length
hollow masonry units shall be interposed between headers shall not exceed 610 mm either vertically
the wall below and the thinner wall above, or or horizontally. In multiwythe walls that are
special units or construction shall be used to thicker than the length of a header, each wythe
transmit the loads from face shells or wythes shall be connected to the adjacent wythe by
above to those below. adjacent headers that overlap a minimum of 75
mm.
A.6.3 Foundation walls
A.7.2.2 Hollow units — Where two or more
A.6.3.1 Foundation walls shall comply with the
wythes are constructed using hollow units, the
requirements of Table A.6, which are applicable
stretcher courses shall be bonded at vertical
when:
intervals not exceeding 860 mm by lapping at least
(a) the foundation wall does not exceed 2.45 75 mm over the unit below, or by lapping at
m in height between lateral supports, vertical intervals not exceeding 430 mm with units
(b) the terrain surrounding foundation walls is which are at least 50 percent greater in thickness
graded to drain surface water away from than the units below.
foundation walls,
A.7.3 Bonding with wall ties or joint
(c) backfill is drained to remove ground water
reinforcement
away from foundation walls,
(d) lateral support is provided at the top of A.7.3.1 Where adjacent wythes of masonry walls
foundation walls prior to backfilling, are bonded with wire size WD 5.0 wall ties or
(e) the length of foundation walls between metal wire of equivalent stiffness embedded in the
perpendicular masonry walls or pilasters is horizontal mortar joints, there shall be at least one
a maximum of 3 multiplied by the metal tie for each 0.42 m2 of wall area. The
basement wall height, maximum vertical distance between ties shall not
(f) the backfill is granular and soil conditions exceed 610 mm, and the maximum horizontal
in the area are non-expansive, and distance shall not exceed 910 mm. Rods or ties
(g) Masonry is laid in running bond using bent to rectangular shape shall be used with hollow
Type M or S mortar. masonry units laid with the cells vertical. In other
walls, the ends of ties shall be bent to 90-degree
A.6.3.2 Where the requirements of Section A.6.3.1
angles to provide hooks no less than 50 mm long.
are not met, foundation walls shall be designed in
Wall ties shall be without drips and shall be non-
accordance with Part 1, Part 2, and Chapter 8 or
adjustable. Additional bonding ties shall be
Chapter 9.
provided at openings, spaced not more than 0.90 m
A.6.4 Foundation piers apart around the perimeter and within 300 mm of
the opening.
Design of foundation piers shall comply with
Appendix A and the following: A.7.3.2 Where adjacent wythes of masonry are
bonded with prefabricated joint reinforcement,

SBC 305-CR- 9
 APPENDIX A—EMPIRICAL DESIGN OF

there shall be at least one cross wire serving as a A.8.3 Floor and roof anchorage
tie for each 0.25 m2 of wall area. The vertical
spacing of the joint reinforcement shall not exceed Floor and roof diaphragms providing lateral
610 mm. Cross wires on prefabricated joint support to masonry shall be connected to the
reinforcement shall be not smaller than wire size masonry by one of the following methods:
WD 4.0 and shall be without drips. The A.8.3.1 Roof loading shall be determined by the
longitudinal wires shall be embedded in the provisions of Section 4.1.2 and, where net uplift
mortar. occurs, uplift shall be resisted entirely by an
A.7.4 Natural or cast stone anchorage system designed in accordance with the
provisions of Sections 8.1 and 8.3 and, Sections
A.7.4.1 Ashlar masonry — In ashlar masonry, 9.1 and 9.3.
uniformly distributed bonder units shall be provided
to the extent of not less than 10 percent of the wall A.8.3.2 Steel joists that are supported by masonry
area. Such bonder units shall extend not less than walls shall bear on and be connected to steel
100 mm into the backing wall. bearing plates. Maximum joist spacing shall be
1.83 m on center. Each bearing plate shall be
A.7.4.2 Rubble stone masonry — Rubble stone anchored to the wall with a minimum of two 12.7
masonry 610 mm or less in thickness shall have mm diameter bolts, or their equivalent. Where
bonder units with a maximum spacing of 0.90 m steel joists are parallel to the wall, anchors shall be
vertically and 0.90 m horizontally, and if the located where joist bridging terminates at the wall
masonry is of greater thickness than 610 mm, shall and additional anchorage shall be provided to
have one bonder unit for each 0.56 m2 of wall comply with Section A.8.3.3.
surface on both sides.
A.8.3.3 Roof and floor diaphragms shall be
A.8—Anchorage anchored to masonry walls with a minimum of
A.8.1 General 12.7 mm diameter bolts at a maximum spacing of
1.83 m on center or their equivalent.
Masonry elements shall be anchored in accordance
with this section. A.8.3.4 Bolts and anchors required by Sections
A.8.3.3 and A.8.3.4 shall comply with the
A.8.2 Intersecting walls following:
Masonry walls depending upon one another for (a) Bolts and anchors at steel floor joists and
lateral support shall be anchored or bonded at floor diaphragms shall be embedded in the
locations where they meet or intersect by one of masonry at least 150 mm or shall comply
the following methods: with Section A.8.3.4(c).
A.8.2.1 Fifty percent of the units at the intersection (b) Bolts at steel roof joists and roof
shall be laid in an overlapping masonry bonding diaphragms shall be embedded in the
pattern, with alternate units having a bearing of not masonry at least 380 mm or shall comply
less than 75 mm on the unit below. with Section A.8.3.4(c).
(c) In lieu of the embedment lengths listed in
A.8.2.2 Walls shall be anchored by steel Sections A.8.3.4(a) and A.8.3.4(b), bolts
connectors having a minimum section of 6.4 mm shall be permitted to be hooked or welded
by 38 mm with ends bent up at least 51 mm, or to not less than 129 mm2 of bond beam
with cross pins to form anchorage. Such anchors reinforcement placed not less than 150
shall be at least 610 mm long and the maximum mm below joist bearing or bottom of
spacing shall be diaphragm.
1.22 m.
A.8.4 Walls adjoining structural framing
A.8.2.3 Walls shall be anchored by joint
reinforcement spaced at a maximum distance of Where walls are dependent upon the structural
200 mm. longitudinal wires of such reinforcement frame for lateral support, they shall be anchored to
shall be at least wire size WD 4.0 and shall extend the structural members with metal anchors or
at least 760 mm in each direction at the otherwise keyed to the structural members. Metal
intersection. anchors shall consist of 12.7-mm bolts spaced at
1.22 m on center embedded 100 mm into the
A.8.2.4 Other metal ties, joint reinforcement or masonry, or their equivalent area.
anchors, if used, shall be spaced to provide
equivalent area of anchorage to that required by
Sections A.8.2.2 through A.8.2.4.

SBC 305-CR- 9
 APPENDIX A—EMPIRICAL DESIGN OF

A. 9—Miscellaneous requirements
A.9.1 Chases and recesses
Masonry directly above chases or recesses wider
than 300 mm shall be supported on lintels.
A.9.2 Lintels
The design of masonry lintels shall be in accordance
with the provisions of Section 5.2.

SBC 305-CR- 9
 APPENDIX A—EMPIRICAL DESIGN OF

TABLES AND FIGURES OF APPENDIX A

Table A.1: Limitations based on building height and basic wind speed

Basic Wind Speed, m/s (meter per second).1

Building Over 51 and Over 54 and
Element Description Less than or less less
Height, m
equal 51 than or equal than or equal Over 56
to-54 to 56
Masonry elements that are part of Not
11 and less Permitted Permitted
the lateral-force-resisting system
Over 55 Not Permitted
Over 18 and less
Interior masonry loadbearing than or equal to Permitted Not Permitted
elements that are not part of the 55
lateral-force-resisting system in Over 11 and
buildings other than enclosed less than or equal Permitted Not Permitted
as defined by SBC 301 to 18
11 and less Permitted Not Permitted
Over 55 Not Permitted
Over 18 and
Exterior masonry elements that are less than or Permitted Not Permitted
not part of the lateral-force-resisting equal to 55
system Over 11 and less
than or equal Permitted Not Permitted
to 18
Exterior masonry elements 11 and less Permitted Not Permitted
1
. Basic wind speed as given in SBC 301

SBC 305-CR- 9
APPENDIX A—EMPIRICAL DESIGN OF

Table A.2: Checklist for use of Appendix A — Empirical Design of Masonry

1. Risk Category IV structures are not permitted to be designed using Appendix A.

2. Partitions are not permitted to be designed using Appendix A.
3. Use of empirical design is limited based on Seismic Design Category, as described in the following
table.
Seismic Design Category Participating Walls Non-Participating Walls, except
partition walls
A Allowed by Appendix A Allowed by Appendix A

B Not Allowed Allowed by Appendix A

C Not Allowed With prescriptive reinforcement per
7.4.3.11
D Not Allowed Not Allowed

1
Lap splices are required to be designed and detailed in accordance with the requirements of Chapter 8 or Chapter 9.

4. Use of empirical design is limited based on wind speed at the project site, as described in Code
A.1.2.3 and Code Table A.1.
5. If wind uplift on roofs result in net tension, empirical design is not permitted (A.8.3.1).
6. Loads used in the design of masonry must be listed on the design drawings (1.2.1(b)).
7. Details of anchorage to structural frames must be included in the design drawings (1.2.1(e)).
8. The design is required to include provisions for volume change (1.2.1(h)). The design drawings are
required to include the locations and sizing of expansion, control, and isolation joints.
9. If walls are connected to structural frames, the connections and walls are required to be designed to resist
the interconnecting forces and to accommodate deflections (4.4).

This provision requires a lateral load and uplift analysis for exterior walls that receive wind load and are
supported by or are supporting a frame or roofing system.
10. Masonry not laid in running bond (for example, stack bond masonry) is required to have
horizontal reinforcement (4.5).
11. A project quality assurance plan is required (3.1) with minimum requirements given in Table 3.1.
12. The resultant of gravity loads must be determined and assured to be located within certain limitations for walls
and piers (A.1.2.1).
13. Ensure compliance of the design with prescriptive floor, roof, and wall-to-structural framing
anchorage requirements, as well as other anchorage requirements ( A.8.3 and A.8.4).
14. Type N mortar is not permitted for foundation walls (A.6.3.1(g)).
15. Design shear wall lengths, spacings, and orientations to meet the requirements of Code A.3.1.

Table A.3: Diaphragm length-to-width ratios

Maximum length-to-width ratio of
Floor or roof diaphragm construction diaphragm panel
Cast-in-place concrete 5:1
Precast concrete 4:1
Metal deck with concrete 3:1
Metal deck with no fill 2:1

SBC 305-CR- 9
 APPENDIX A—EMPIRICAL DESIGN OF

Table A.4: Allowable compressive stresses for empirical design of masonry

Construction; compressive strength of masonry unit, Allowable compressive stresses.1 based
gross area, MPa on gross cross-sectional area,
MPa
Type M or S mortar Type N mortar
Solid masonry of brick and other solid units of clay or shale; sand-
lime or concrete brick:
55.00 or greater 2.41 2.07
31.00 1.55 1.38
17.20 1.10 0.97
10.30 0.79 0.69
Grouted masonry of clay or shale; sand-lime or concrete:
31.00 or greater 1.55 1.38
17.20 1.10 0.97
10.30 0.79 0.69
Solid masonry of solid concrete masonry units:
20.70 or greater 1.55 1.38
13.80 1.10 0.97
8.30 0.79 0.69
Masonry of hollow load-bearing units of clay or shale.2:
13.80 or greater 0.97 0.83
10.30 0.79 0.69
6.90 0.52 0.48
4.80 0.41 0.38
Masonry of hollow load-bearing concrete masonry units, up to and
including 200 mm nominal thickness:
13.80 or greater 0.97 0.83
10.30 0.79 0.69
6.90 0.52 0.48
4.80 0.41 0.38
Masonry of hollow load-bearing concrete masonry units, greater
than 200 to 300 mm nominal thickness:
13.80 or greater 0.86 0.76
10.30 0.72 0.62
6.90 0.45 0.41
4.80 0.38 0.35
Masonry of hollow load-bearing concrete masonry units, 300
mm nominal thickness and greater:
13.80 or greater 0.79 0.69
10.30 0.66 0.59
6.90 0.41 0.38
4.80 0.35 0.31
Multiwythe non-composite walls.2:
Solid units:
17.20 or greater 1.10 0.97
10.30 0.79 0.69
Hollow units of clay or shale 0.52 0.48
Hollow units of concrete masonry of nominal thickness,
up to and including 200 mm: 0.52 0.48
greater than 200-300 mm: 0.48 0.45
300 mm and greater: 0.41 0.38
Stone ashlar masonry:
Granite 4.96 4.41
Limestone or marble 3.10 2.76
Sandstone or cast stone 2.48 2.21
Rubble stone masonry:
Coursed, rough, or random 0.83 0.69
.1 Linear interpolation shall be permitted for determining allowable stresses for masonry units having compressive strengths which are intermediate
between those given in the table.
.2 In non-composite walls, where floor and roof loads are carried upon one wythe, the gross cross-sectional area is that of the wythe under load; if both
wythes are loaded, the gross cross-sectional area is that of the wall minus the area of the cavity between the wythes.

SBC 305-CR- 9
APPENDIX A—EMPIRICAL DESIGN OF

Table A.5: Diaphragm length-to-width ratios

Construction Maximum 𝑙/𝑡 or ℎ/𝑡
Load-bearing walls
Solid units or fully grouted 20
Other than solid units or fully grouted 18
Non-load-bearing walls
Exterior 18

Table A.6: Diaphragm length-to-width ratios

Wall construction Nominal wall Maximum depth of
thickness, mm unbalanced backfill, m
Masonry of hollow units 200 1.50
250 1.80
300 2.10
Masonry of solid units 200 1.50
250 2.10
300 2.10
Fully grouted masonry 200 2.10
250 2.45
300 2.45

Figure A.2: Graphical representation of 𝑊𝑆 and 𝑊𝑇

SBC 305-CR- 9
APPENDIX A—EMPIRICAL DESIGN OF

SBC 305-CR- 9
 APPENDIX B—DESIGN OF MASONRY

APPENDIX B—DESIGN OF MASONRY INFILL

B. 1—General B.2.1.3 In-plane isolation joints shall be free of

B.1.1 Scope mortar, debris, and other rigid materials, and shall
be permitted to contain resilient material, provided
This chapter provides minimum requirements for that the compressibility of that material is
the structural design of concrete masonry, clay considered in establishing the required size of the
masonry, and AAC masonry infills, either non- joint.
participating or participating. Infills shall comply
with the requirements of Part 1, Part 2, excluding B.2.2 Design of non-participating infills for out-
Sections 5.2, 5.3, 5.4, and 5.5, Section A1, and of-place loads
either Section B2 or B3. Connectors supporting non-participating infills
B.1.2 Required strength against out-of-plane loads shall be designed to
meet the requirements of Sections B.2.2.1
Required strength shall be determined in through
accordance with the strength design load B.2.2.4. The infill shall be designed to meet the
combinations specified in SBC 301. requirements of Section B.2.2.5.
B.1.3 Design strength B.2.2.1 The connectors shall be attached to the
Infills shall be proportioned so that the design bounding frame.
strength equals or exceeds the required strength. B.2.2.2 The connectors shall not transfer in-plane
Design strength is the nominal strength multiplied forces.
by the strength-reduction factor, 𝜙, as specified in
Section B.1.4. B.2.2.3 The connectors shall be designed to satisfy
the requirements of SBC 301
B.1.4 Strength-reduction factors
B.2.2.4 The connectors shall be spaced at a
The value of 𝜙 shall be taken as 0.60, and applied maximum of 1.22 m along the supported perimeter
to the shear, flexure, and axial strength of a of the infill.
masonry infill panel.
B.2.2.5 The infill shall be designed to resist out-of-
B.1.5 Limitations place bending between connectors in accordance
Partial infills and infills with openings shall not be with Section 9.2 for unreinforced concrete
considered as part of the lateral force-resisting masonry or clay masonry infill, Section 11.2 for
system. Their effect on the bounding frame, unreinforced AAC masonry infill, Section 9.3 for
however, shall be considered. reinforced concrete masonry or clay masonry
infill, or Section
B.2—Non-participating infills 11.3 for reinforced AAC masonry infill.
Non-participating infills shall comply with the B.3—Participating infills
requirements of Sections B.2.1 and B.2.2.
Participating infills shall comply with the
B.2.1 In-plane isolation joints for non- requirements of Sections B.3.1 through B.3.6.
participating infills
B.3.1 General
B.2.1.1 In-plane isolation joints shall be designed
between the infill and the sides and top of the Infills with in-plane isolation joints not meeting
bounding frame. the requirements of Section B.2.1 shall be
considered as participating infills. For such infills
B.2.1.2 In-plane isolation joints shall be specified the displacement shall be taken as the bounding
to be at least 9.5 mm wide in the plane of the infill, frame displacement minus the specified width of
and shall be sized to accommodate the design the gap between the bounding column and infill.
displacements of the bounding frame.
B.3.1.1 The maximum ratio of the nominal vertical
dimension to nominal thickness of participating
infills shall not exceed 30.

SBC 305-CR- 9
 APPENDIX B—DESIGN OF MASONRY

B.3.1.2 Participating infills that are not constructed

in contact with the bounding beam or slab adjacent 𝜆𝑠𝑡𝑟𝑢𝑡
to their upper edge shall be designed in accordance 4 𝐸 𝑡𝑛𝑒𝑡 𝑖𝑛𝑓𝑠𝑖𝑛2𝜃𝑠𝑡𝑟𝑢𝑡 Equation B-2a
with Section B.3.1.2.1 or B.3.1.2.2. = √ 𝑚 4𝐸 𝐼 ℎ
B.3.1.2.1 Where the specified gap between 𝑏𝑐 𝑖𝑛𝑓
𝑏𝑐
the bounding beam or slab at the top of the infill is For the design of concrete masonry and clay
less than 9.5 mm or the gap is not sized to masonry infill; and
accommodate design displacements, the infill shall
be designed in accordance with Sections B.3.4 and 𝜆𝑠𝑡𝑟𝑢𝑡
B.3.5, except that the calculated stiffness and
strength of the infill shall be multiplied by a factor 4 𝐸𝐴𝐴𝐶 𝑡𝑛𝑒𝑡 𝑖𝑛𝑓𝑠𝑖𝑛2𝜃𝑠𝑡𝑟𝑢𝑡 Equation B-2b
=
of 0.5. √
4𝐸 𝑏𝑐𝐼 ℎ
𝑖
B.3.1.2.2 If the gap between the infill and
the overlying bounding beam or slab is sized such for the design of AAC masonry infill.
that in-plane forces cannot be transferred between
B.3.4.2 Design forces in equivalent struts, as
the bounding beam or slab and the infill, the infill
defined in Section B.3.4.1, shall be determined
shall be considered a partial infill and shall comply
from an elastic analysis of a braced frame
with Section B.1.5.
including such equivalent struts.
B.3.2 In-plane connection requirements for
participating infills B.3.4.3 𝑉𝑛 𝑖𝑛𝑓 shall be the smallest of (a), (b), and
(c) for concrete masonry and clay masonry infill
Mechanical connections between the infill and the and (b), (d), and (e) for AAC masonry infill:
bounding frame shall be permitted provided that (150 mm)𝑡 𝑓′ Equation B-3
they do not transfer in-plane forces between the 𝑛𝑒𝑡 𝑖𝑛𝑓 𝑚
infill and the bounding frame. (d) the calculated horizontal component of the
B.3.3 Out-of-plane connection requirements for force in the equivalent strut at a horizontal
participating infills racking displacement of 25 mm.
B.3.3.1 Participating infills shall be supported out- 𝑉𝑛/1.5 Equation B-4
of-plane by connectors attached to the bounding
frame. where 𝑉𝑛 is the smallest nominal shear strength
from Section 9.2.6, calculated along a bed joint.
B.3.3.2 Connectors providing out-of-plane support
shall be designed to satisfy the requirements of (150 mm)𝑡𝑛𝑒𝑡 𝑖𝑛𝑓𝑓′ Equation B-5
SBC 301. 𝐴

B.3.3.3 Connectors providing out-of-plane support 𝑉𝑛𝐴𝐴𝐶 /1.5 Equation B-6

shall be spaced at a maximum of 1.22 m along the
supported perimeter of the infill. where 𝑉𝑛𝐴𝐴𝐶 is the smallest nominal shear strength
from Section 11.2.5, calculated along a bed joint.
B.3.4 Design of participating infills for in-plane
forces B.3.5 Design of frame elements with
participating infills for in-plane loads
B.3.4.1 Unless the stiffness of the infill is obtained
by a more comprehensive analysis, a participating B.3.5.1 Design each frame member not in contact
infill shall be analyzed as an equivalent strut, with an infill for shear, moment, and axial force
capable of resisting compression only; whose not less than the results from the equivalent strut
width is calculated using Equation B-1; whose frame analysis.
thickness is the specified thickness of the infill; B.3.5.2 Design each bounding column in contact
and whose elastic modulus is the elastic modulus with an infill for shear and moment equal to not
of the infill. less than 1.1 multiplied by the results from
the
0.3
𝑤𝑖𝑛𝑓 = Equation B-1 equivalent strut frame analysis, and for axial force
𝜆𝑠𝑡𝑟𝑢𝑡𝑐𝑜𝑠𝜃𝑠𝑡𝑟𝑢𝑡 not less than the results from that analysis. In
addition, increase the design shear at each end of
Where: the column by the horizontal component of

SBC 305-CR- 1
 APPENDIX B—DESIGN OF MASONRY

t
h
e

SBC 305-CR- 1
 APPENDIX B—DESIGN OF MASONRY

equivalent strut force acting on that end under

design loads. 𝑞𝑛 𝑖𝑛𝑓 Equation
= 729,000(𝑓 ) ′
𝑡 ( 𝛼𝑎𝑟𝑐ℎ
0.75 2 B-7b
𝐴𝐴𝐶 𝑖𝑛𝑓
B.3.5.3 Design each beam or slab in contact with 𝑙𝑖𝑛𝑓 2.5
an infill for shear and moment equal to at least 𝛽𝑎𝑟𝑐ℎ
1.1
+ )
multiplied by the results from the equivalent strut ℎ𝑖𝑛𝑓 2.5

frame analysis, and for an axial force not less than

the results from that analysis. In addition, increase Where:
the design shear at each end of the beam or slab by
the vertical component of the equivalent strut force 𝛼 = 1 (𝐸 𝐼 ℎ2 )0.25 Equation B-8
acting on that end under design loads. 𝑎𝑟𝑐ℎ 𝑏𝑐 𝑏𝑐 𝑖𝑛𝑓
ℎ𝑖𝑛𝑓
B.3.6 Design of participating infills for out-of- < 50
plane forces
The nominal out-of-plane flexural capacity to resist
𝛽 = 1 (𝐸 𝐼 𝑙2 )0.25 Equation B-9
out-of-plane forces of the infill per unit area shall 𝑎𝑟𝑐ℎ
𝑙𝑖𝑛𝑓 𝑏𝑏 𝑏𝑏 𝑖𝑛𝑓
be determined in accordance with Equation B-7a for < 50
concrete masonry and clay masonry and Equation
B-7b for AAC masonry:
In Equation B-7, 𝑡𝑖𝑛𝑓 shall not be taken greater than
1/8 ℎ𝑖𝑛𝑓. When bounding columns of different
𝑞𝑛 𝑖𝑛𝑓 Equation cross-sectional properties are used on either side of
𝛼 B-7a the infill, average properties shall be used to
0.75
= 729,000(𝑓 ′) 𝑡 2
𝑖𝑛𝑓
( calculate this capacity. When bounding beams of
𝑚
𝛽𝑎𝑟𝑐ℎ 𝑙𝑖𝑛𝑓 2.5 different cross-sectional properties are used above
) and below the infill, average properties shall be
+ 2.5
ℎ𝑖𝑛𝑓 used to calculate this capacity. In the case of a
single story frame, the cross-sectional properties of
the bounding beam above the infill shall be used to
calculate this capacity. When a side gap is present,
𝛼𝑎𝑟𝑐ℎ shall be taken as zero. When a top gap is
present, 𝛽𝑎𝑟𝑐ℎ shall be taken as zero.

SBC 305-CR- 1
 APPENDIX C—LIMIT DESIGN

APPENDIX C—LIMIT DESIGN METHOD

C.0—General the yield mechanism associated with the limiting

The limit design method shall be permitted to be base-shear strength, 𝑉𝑙𝑖𝑚 shall satisfy the following:
applied to a line of lateral load resistance
consisting of special reinforced masonry shear 𝜙𝑉𝑙𝑖𝑚 ≥ 𝑉𝑢𝑏 Equation C-1
walls that are designed per the strength design
provisions of Chapter 9, except that the The value of 𝜙 assigned to the mechanism strength
provisions of Section shall be taken as 0.8. The base-shear demand, 𝑉𝑢𝑏,
9.3.3.5 and Section 9.3.6.5 shall not apply. shall be determined from analytical procedures
permitted in Section 12.6 of SBC 301.
C.1—Yield mechanism
C.3—Mechanism deformation
It shall be permitted to use limit analysis to
determine the controlling yield mechanism and its The rotational deformation demand on plastic
corresponding base-shear strength, 𝑉𝑙𝑖𝑚, for a line hinges shall be determined by imposing the design
of lateral load resistance, provided that (a) through displacement, 𝛿𝑢, at the roof level of the yield
(e) are satisfied: mechanism. The rotational deformation capacity of
plastic hinges shall satisfy C.3.1 to C.3.3.
(a) The relative magnitude of lateral seismic
forces applied at each floor level shall C.3.1 The rotational deformation capacity of
correspond to the loading condition plastic hinges shall be taken as 0.5𝑙𝑤 𝜀𝑚𝑢/𝑐. The
producing the maximum base shear at the value of 𝑐 shall be calculated for the 𝑃𝑢
line of resistance in accordance with corresponding to Load Combination 5 of Section
analytical procedures permitted in Section 2.3.2 of SBC 301.
12.6 of SBC 301. C.3.2 The angular deformation capacity of
(b) In the investigation of potential yield masonry components whose plastic hinge
mechanisms induced by seismic loading, strengths are limited by shear as specified in C.1
plastic hinges shall be considered to form (d), shall be taken as 1/400. The angular
at the faces of joints and at the interfaces deformation capacity shall be permitted to be taken
between masonry components and the as 1/200 for masonry components satisfying the
foundation. following requirements:
(c) The axial forces associated with Load
Combination 7 of Section 2.3.2 of SBC (a) The areas of transverse and longitudinal
301 shall be used when determining the reinforcement shall each not be less than
strength of plastic hinges, except that axial 0.001 multiplied by the gross cross-
loads due to horizontal seismic forces shall sectional area of the component, using
be permitted to be neglected. specified dimensions;
(d) The strength assigned to plastic hinges (b) Spacing of transverse and longitudinal
shall be based on the nominal flexural reinforcement shall not exceed the
strength, smallest of 610 mm, 𝑙𝑤/2, and ℎ𝑤/2.
𝑀𝑛, but shall not exceed the moment (c) Reinforcement ending at a free edge of
associated with one-half of the nominal masonry shall be anchored around
shear strength, 𝑉𝑛, calculated using MSJC perpendicular reinforcing bars with a
Section 9.3.4.1.2. standard hook.
(e) At locations other than the plastic hinges C.3.3 The 𝑃𝑢 corresponding to load combination
identified in C.1(b), moments shall not 5 of Section 2.3.2 of SBC 301 shall not exceed a
exceed the strengths assigned in C.1(d) compressive stress of 0.3𝑓′ 𝐴 at plastic hinges in
using the assumptions of C.1(c). 𝑚
the controlling mechanism.
C.2—Mechanism strength

SBC 305-CR- 1
 APPENDIX D—MASONRY

APPENDIX D—MASONRY FIREPLACES

D.1—General. Dia 12 vertical bars shall be provided for each

The construction of masonry fireplaces, consisting additional 1000 mm in width or fraction thereof.
of concrete or masonry, shall be in accordance D.4.2 Horizontal reinforcing. Vertical
with this Appendix. reinforcement shall be placed enclosed within 6
D.2—Fireplace drawings. mm ties or other reinforcing of equivalent net
cross- sectional area, spaced not to exceed 450 mm
The construction documents shall describe in on center in concrete; or placed in the bed joints of
sufficient detail the location, size and con- unit masonry at a minimum of every 450 mm of
struction of masonry fireplaces. The thickness vertical height. Two such ties shall be provided at
and characteristics of materials and the each bend in the vertical bars.
clearances from walls, partitions and ceilings D.5—Seismic anchorage
shall be indicated.
Masonry fireplaces and foundations shall be
D.3—Footings and foundations. anchored at each floor, ceiling or roof line more
Footings for masonry fireplaces and their than 1800 mm above grade with two 5 mm by 25
chimneys shall be constructed of concrete or solid mm straps embedded a minimum of 300 mm into
masonry at least 300 mm thick and shall extend at the chimney. Straps shall be hooked around the
least 150 mm beyond the face of the fireplace or outer bars and extend 150 mm beyond the bend.
foundation wall on all sides. Footings shall be Each strap shall be fastened to a minimum of four
founded on natural undisturbed earth or engineered floor joists with two 13 mm bolts.
fill below frost depth. In areas not subjected to Exception: Seismic anchorage is not required for
freezing, footings shall be at least 300 mm below the following:
finished grade.
(1) In structures assigned to Seismic Design
D.3.1 Ash dump cleanout. Cleanout openings, Category A or B.
located within foundation walls below fireboxes,
when provided, shall be equipped with ferrous (2) Where the masonry fireplace is
metal or masonry doors and frames constructed to constructed completely within the exterior
remain tightly closed, except when in use. walls.
Cleanouts shall be accessible and located so that D.6—Firebox walls
ash removal will not create a hazard to
combustible materials. Masonry fireboxes shall be constructed of solid
masonry units, hollow masonry units grouted
D.4—Seismic reinforcement solid, stone or concrete. When a lining of firebrick
In structures assigned to Seismic Design Category at least 50 mm in thickness or other approved
A or B, seismic reinforcement is not required. In lining is pro- vided, the minimum thickness of
structures assigned to Seismic Design Category C back and sidewalls shall each be 200 mm of solid
or D, masonry fireplaces shall be reinforced and masonry, including the lining. The width of joints
anchored in accordance with Sections D.4.1, D.4.2 between firebricks shall be not greater than 6 mm.
and D.5. When no lining is provided, the total minimum
thickness of back and sidewalls shall be 250 mm
D.4.1 Vertical reinforcing. For fireplaces with of solid masonry. Firebrick shall conform to
chimneys up to 1000 mm wide, four Dia 12 ASTM C 27 or ASTM C 1261 and shall be laid
continu- ous vertical bars, anchored in the with medium-duty refractory mortar conforming to
foundation, shall be placed in the concrete between ASTM C 199.
wythes of solid masonry or within the cells of
hollow unit masonry and grouted in accordance D.6.1 Steel fireplace units. Steel fireplace units
with Article 202 of TMS 602/ACI530.1/ASCE6. are permitted to be installed with solid masonry to
For fireplaces with chim- neys greater than 1000 form a masonry fireplace provided they are
mm wide, two additional installed according to either the requirements of

SBC 305-CR- 1
 APPENDIX D—MASONRY

their listing or the requirements of this section. of front, back and sidewalls shall be 150 mm of
Steel fireplace units incorporating a steel firebox solid masonry, including the lining. Firebrick shall
lining shall be constructed with steel not less than conform to ASTM C 1261 and shall be laid with
6 mm in thickness, and an air-circulating chamber refractory mortar conforming to ASTM C 199.
which is ducted to the interior of the building. The Vitrified clay linings shall conform to ASTM C
firebox lining shall be encased with solid masonry 315.
to provide a total thickness at the back and sides of
not less than 200 mm, of which not less than 100 D.9.1 Smoke chamber dimensions. The inside
mm shall be of solid masonry or concrete. height of the smoke chamber from the fireplace
Circulating air ducts employed with steel fireplace throat to the beginning of the flue shall be not
units shall be constructed of metal or masonry. greater than the inside width of the fireplace
opening. The inside surface of the smoke chamber
D.7—Firebox dimensions shall not be inclined more than 45 degrees (0.76
The firebox of a concrete or masonry fireplace rad) from vertical when prefabricated smoke
shall have a minimum depth of 500 mm. The cham- ber linings are used or when the smoke
throat shall be not less than 200 mm above the chamber walls are rolled or sloped rather than
fireplace opening. The throat opening shall not be corbeled. When the inside surface of the smoke
less than 100 mm in depth. The cross-sectional chamber is formed by corbeled masonry, the walls
area of the passageway above the firebox, shall not be corbeled more than 30 degrees (0.52
including the throat, damper and smoke chamber, rad) from vertical.
shall be not less than the cross-sectional area of the D.10—Hearth and hearth extension
flue.
Masonry fireplace hearths and hearth extensions
Exception: Rumford fireplaces shall be permitted shall be constructed of concrete or masonry,
provided that the depth of the fireplace is not less supported by noncombustible materials, and
than 300 mm and at least one-third of the width of reinforced to carry their own weight and all
the fireplace opening, and the throat is not less imposed loads. No combustible material shall
than 300 mm above the lintel, and at least 1/20, remain against the underside of hearths or hearth
the cross-sectional area of the fireplace opening. extensions after construction.
D.8—Lintel and throat D.10.1 Hearth thickness. The minimum thickness
Masonry over a fireplace opening shall be of fireplace hearths shall be 100 mm.
supported by a lintel of noncombustible material. D.10.2 Hearth extension thickness. The minimum
The minimum required bearing length on each end thickness of hearth extensions shall be 50 mm.
of the fireplace opening shall be 100 mm. The
fireplace throat or damper shall be located not less Exception: When the bottom of the firebox
than 200 mm above the top of the fireplace opening. opening is raised not less than 200 mm above the
top of the hearth extension, a hearth extension of
D.8.1 Damper. Masonry fireplaces shall be not less than 10 mm brick, concrete, stone, tile or
equipped with a ferrous metal damper located not other approved noncombustible material is
less than 200 mm above the top of the fireplace permitted.
opening. Dampers shall be installed in the
fireplace or at the top of the flue venting the D.11—Hearth extension dimensions
fireplace, and shall be operable from the room Hearth extensions shall extend not less than 400
containing the fireplace. Damper controls shall be mm in front of, and not less than 200 mm beyond,
permitted to be located in the fireplace. each side of the fireplace opening. Where the
D.9—Smoke chamber walls fireplace opening is 0.6 m2 or larger, the hearth
extension shall extend not less than 500 mm in
Smoke chamber walls shall be constructed of solid front of, and not less than 300 mm beyond, each
masonry units, hollow masonry units grouted side of the fireplace opening.
solid, stone or concrete. The total minimum
thickness of front, back and sidewalls shall be 200 D.12—Fireplace clearance
mm of solid masonry. The inside surface shall be Any portion of a masonry fireplace located in the
parged smooth with refractory mortar conforming interior of a building or within the exterior wall of
to ASTM C 199. When a lining of firebrick not a building shall have a clearance to combustibles
less than 50 mm thick, or a lining of vitrified clay of not less than 50 mm from the front faces and
not less than 16 mm thick, is provided, the total sides of masonry fireplaces and not less than
minimum thickness 100 mm

SBC 305-CR- 1
 APPENDIX D—MASONRY

from the back faces of masonry fireplaces. The fastened in place. The fire blocking of spaces
airspace shall not be filled, except to provide fire between wood joists, beams or headers shall be to
blocking in accordance with Section D.13. a depth of 25 mm and shall only be placed on
Exceptions: strips of metal or metal lath laid across the spaces
between combustible material and the chimney.
(1) Masonry fireplaces listed and labeled for
use in contact with combustibles in D.14—Exterior air
accordance with UL 127 and installed in Factory-built or masonry fireplaces covered in this
accordance with the manufacturer's section shall be equipped with an exterior air
instructions are permitted to have supply to ensure proper fuel combustion unless the
combustible material in contact with their room is mechanically ventilated and controlled so
exterior surfaces. that the indoor pressure is neutral or positive.
(2) When masonry fireplaces are constructed
D.14.1 Factory-built fireplaces — Exterior
as part of masonry or concrete walls, combustion air ducts for factory-built fireplaces
combustible materials shall not be in shall be listed components of the fireplace, and
contact with the masonry or concrete installed according to the fireplace manufacturer's
walls less than 300 mm from the inside instructions.
surface of the nearest firebox lining.
D.14.2 Masonry fireplaces — Listed combustion
(3) Exposed combustible trim and the edges
air ducts for masonry fireplaces shall be installed
of sheathing materials, such as wood according to the terms of their listing and
siding, flooring and drywall, are manufacturer's instructions.
permitted to abut the masonry fireplace
sidewalls and hearth extension, in D.14.3 Exterior air intake — The exterior air
accordance with Figure D.1, provided such intake shall be capable of providing all combustion
combustible trim or sheathing is not less air from the exterior of the dwelling. The exterior
than 300 mm from the inside surface of air intake shall not be located within a garage,
the nearest firebox lining. attic, basement or crawl space of the dwelling nor
shall the air intake be located at an elevation
(4) Exposed combustible mantels or trim is
higher than the firebox. The exterior air intake
permitted to be placed directly on the shall be covered with a corrosion-resistant screen
masonry fireplace front surrounding the of 6 mm mesh.
fireplace opening, provided such
combustible materials shall not be placed D.14.4 Clearance — Unlisted combustion air
within 150 mm of a fireplace opening. ducts shall be installed with a minimum 25 mm
Combustible material directly above and clearance to combustibles for all parts of the duct
within 300 mm of the fireplace opening within 1500 mm of the duct outlet.
shall not project more than 3 mm for each D.14.5 Passageway — The combustion air
25 mm distance from such opening. passageway shall be not less than 3870 mm2 and
Combustible materials located along the not more than 0.035 m2, except that combustion
sides of the fireplace opening that project air systems for listed fireplaces or for fireplaces
more than 38 mm from the face of the tested for emissions shall be constructed according
fireplace shall have an additional to the fireplace manufacturer's instructions.
clearance equal to the projection.
D.14.6 Outlet — The exterior air outlet is
D.13—Fireplace fire blocking permitted to be located in the back or sides of the
All spaces between fireplaces and floors and firebox chamber or within 600 mm of the firebox
ceilings through which fireplaces pass shall be fire opening on or near the floor. The outlet shall be
blocked with noncombustible material securely closable and designed to prevent burning material
from dropping into concealed combustible spaces.

SBC 305-CR- 1
APPENDIX D—MASONRY

TABLES AND FIGURES OF APPENDIX D

Figure D.1: Illustration of exception to fireplace clearance provision

SBC 305-CR- 1
 APPENDIX E—MASONRY

APPENDIX E—MASONRY HEATERS

E.1—Definition Seismic reinforcing shall not be required within

A masonry heater is a heating appliance the body of a masonry heater with a height that is
constructed of concrete or solid masonry, equal to or less than 3.5 times its body width and
hereinafter referred to as "masonry", which is where the masonry chimney serving the heater is
designed to absorb and store heat from a solid fuel not supported by the body of the heater. Where the
fire built in the firebox by routing the exhaust masonry chimney shares a common wall with the
gases through internal heat exchange channels in facing of the masonry heater, the chimney portion
which the flow path downstream of the firebox of the structure shall be reinforced in accordance
may include flow in a horizontal or downward with Appendix F.
direction before entering the chimney and which E.5—Masonry heater clearance
delivers heat by radiation from the masonry
surface of the heater. Combustible materials shall not be placed within
900 mm or the distance of the allowed reduction
E.2—Installation method from the outside surface of a masonry
Masonry heaters shall be installed in accordance heater in accordance with NFPA 211, Section
with this Appendix and comply with one of the 12.6, and the required space between the heater
fol- lowing: and combustible material shall be fully vented to
permit the free flow of air around all heater
(1) Masonry heaters shall comply with the surfaces.
requirements of ASTM E 1602.
Exceptions:
(2) Masonry heaters shall be listed and
labeled in accordance with UL 1482 or (1) Where the masonry heater wall thickness
EN 15250 and installed in accordance is at least 200 mm of solid masonry and
with the manufacturer's instructions. the wall thickness of the heat exchange
channels is not less than 125 mm of solid
E.3—Footings and foundation masonry, combustible materials shall not
The firebox floor of a masonry heater shall be a be placed within 100 mm of the outside
minimum thickness of 100 mm of noncombustible surface of a masonry heater. A clearance
material and be supported on a noncombustible of not less than 200 mm shall be provided
footing and foundation in accordance with Section between the gas-tight capping slab of the
F3. heater and a combustible ceiling.

E.4—Seismic reinforcing (2) Masonry heaters listed and labeled in

accordance with UL 1482 or EN 15250
In structures assigned to Seismic Design Category and installed in accordance with the
D, E or F, masonry heaters shall be anchored to the manufacturer's instructions.
masonry foundation in accordance with Section
F3.

SBC 305-CR- 1
 APPENDIX F—MASONRY

APPENDIX F—MASONRY CHIMNEYS

F.1—General Masonry chimneys and foundations shall be

The construction of masonry chimneys consisting anchored at each floor, ceiling or roof line more
of solid masonry units, hollow masonry units than 1800 mm above grade with two 5 mm by 25
grouted solid, stone or concrete shall be in mm straps embedded not less than 300 mm into
accordance with this Appendix. the chimney. Straps shall be hooked around the
outer bars and extend 150 mm beyond the bend.
F.2—Footings and foundations Each strap shall be fastened to not less than four
Footings for masonry chimneys shall be floor joists with two 13 mm bolts.
constructed of concrete or solid masonry not less Exception: Seismic anchorage is not required for
than 300 mm thick and shall extend at least 150 the following;
mm beyond the face of the foundation or support
wall on all sides. Footings shall be founded on (1) In structures assigned to Seismic Design
natural undisturbed earth or engineered fill below Category A or B.
frost depth. In areas not subjected to freezing, (2) Where the masonry fireplace is
footings shall be not less than 300 mm below constructed completely within the exterior
finished grade. walls.
F.3—Seismic reinforcement F.5—Corbeling
In structures assigned to Seismic Design Category Masonry chimneys shall not be corbeled more than
A or B, seismic reinforcement is not required. In half of the chimney's wall thickness from a wall or
structures assigned to Seismic Design Category C foundation, nor shall a chimney be corbeled from a
or D, masonry chimneys shall be reinforced and wall or foundation that is less than 300 mm in
anchored in accordance with Sections F.3.1, F.3.2 thickness unless it projects equally on each side of
and F.4. the wall, except that on the second story of a two-
F.3.1 Vertical reinforcement. For chimneys up story dwelling, corbeling of chimneys on the
to 1000 mm wide, four Dia 12 continuous vertical exterior of the enclosing walls is permitted to
bars anchored in the foundation shall be placed in equal the wall thickness. The projection of a single
the concrete between wythes of solid masonry or course shall not exceed one-half the unit height or
within the cells of hollow unit masonry and one- third of the unit bed depth, whichever is less.
grouted in accordance with Article 2.2 of TMS F.6—Changes in dimension
602/ACI530.1/ASCE6. Grout shall be prevented
from bonding with the flue liner so that the flue The chimney wall or chimney flue lining shall not
liner is free to move with thermal expansion. For change in size or shape within 150 mm above or
chimneys greater than 1000 mm wide, two below where the chimney passes through floor
additional Dia 12 vertical bars shall be provided components, ceiling components or roof com-
for each additional 1000 mm in width or fraction ponents.
thereof. F.7—Offsets
F.3.2 Horizontal reinforcement. Vertical Where a masonry chimney is constructed with a
reinforcement shall be placed enclosed within 6 fireclay flue liner surrounded by one wythe of
mm ties, or other reinforcing of equivalent net masonry, the maximum offset shall be such that
cross- sectional area, spaced not to exceed 450 mm the centerline of the flue above the offset does not
on center in concrete, or placed in the bed joints of extend beyond the center of the chimney wall
unit masonry, at not less than every 450 mm of below the offset. Where the chimney offset is
vertical height. Two such ties shall be provided at supported by masonry below the offset in an
each bend in the vertical bars. approved manner, the maximum offset limitations
F.4—Seismic anchorage shall not apply. Each individual corbeled
masonry course of the

SBC 305-CR- 10
 APPENDIX F—MASONRY

offset shall not exceed the projection limitations flashing and weep holes shall be provided as required by
specified in Section F5. CHAPTER 12.
F.8—Additional load
Chimneys shall not support loads other than their
own weight unless they are designed and con-
structed to support the additional load. Masonry
chimneys are permitted to be constructed as part of
the masonry walls or concrete walls of the
building.
F.9—Termination
Chimneys shall extend not less than 600 mm
higher than any portion of the building within
3000 mm, but shall not be less than 900 mm above
the highest point where the chimney passes
through the roof.
F.9.1 Chimney caps. Masonry chimneys shall
have a concrete, metal or stone cap, sloped to shed
water, a drip edge and a caulked bond break
around any flue liners in accordance with ASTM C
1283.
F.9.2 Spark arrestors. Where a spark arrestor is
installed on a masonry chimney, the spark arrestor
shall meet all of the following requirements:
(1) The net free area of the arrestor shall be
not less than four times the net free area
of the outlet of the chimney flue it serves.
(2) The arrestor screen shall have heat and
corrosion resistance equivalent to 19-gage
galvanized steel or 24-gage stainless
steel.
(3) Openings shall not permit the passage of
spheres having a diameter greater than 13
mm nor block the passage of spheres
having a diameter less than 10 mm.
(4) The spark arrestor shall be accessible for
cleaning and the screen or chimney cap
shall be removable to allow for cleaning
of the chimney flue.
F.9.3 Rain caps. Where a masonry or metal rain
cap is installed on a masonry chimney, the net free
area under the cap shall be not less than four times
the net free area of the outlet of the chimney flue it
serves.
F.10—Wall thickness
Masonry chimney walls shall be constructed of
concrete, solid masonry units or hollow masonry
units grouted solid with not less than 100 mm
nominal thickness.
F.10.1 Masonry veneer chimneys. Where masonry
is used as veneer for a framed chimney, through

SBC 305-CR- 11
 APPENDIX F—MASONRY

F.11—Flue lining (material) F.11.1.5 for marking).

Masonry chimneys shall be lined. The F.11.1.5 Notice of usage. When a flue is relined
lining material shall be appropriate for with a material not complying with Section F.11.1,
the type of appliance connected, the chimney shall be plainly and permanently
according to the terms of the appliance identified by a label attached to a wall, ceiling or
listing and the manufacturer's other conspicuous location adjacent to where the
instructions. connector enters the chimney. The label shall
include the following message or equivalent
F.11.1 Residential-type appliances
(general). Flue lining systems shall
comply with one of the following:
(1) Clay flue lining complying
with the requirements of
ASTM C 315.
(2) Listed chimney lining systems
complying with UL 1777.
(3) Factory-built chimneys or
chimney units listed for
installation within masonry
chimneys.
(4) Other approved materials that
will resist corrosion, erosion,
softening or cracking from
flue gases and condensate at
temperatures up to 982°C.
F.11.1.1 Flue linings for specific
appliances. Flue linings other than
those covered in Section F.11.1
intended for use with specific
appliances shall comply with Sections
F.11.1.2 through F.11.1.4 and Sections
F.11.2 and F.11.3.
F.11.1.2 Gas appliances. Flue lining
systems for gas appliances shall be in
accordance with the International Fuel
Gas Code.
F.11.1.3 Pellet fuel-burning
appliances. Flue lining and vent
systems for use in masonry chimneys
with pellet fuel-burning appliances
shall be limited to flue lining systems
complying with Section F.11.1 and
pellet vents listed for installation
within masonry chimneys (see Section
F.11.1.5 for marking).
F.11.1.4 Oil-fired appliances approved
for use with L-vent. Flue lining and
vent systems for use in masonry
chimneys with oil-fired appliances
approved for use with Type L vent
shall be limited to flue lining
systems complying with Section
F.11.1 and listed chimney liners
complying with UL 641 (see Section

SBC 305-CR- 11
 APPENDIX F—MASONRY

language: "This chimney is for use only with (type F.11.3.4 Termination height. Concrete and
or category of appliance) that burns (type of fuel). masonry chimneys for high-heat appliances shall
Do not connect other types of appliances." extend not less than 6100 mm higher than any
F.11.2 Concrete and masonry chimneys for portion of any building within 15200 mm.
medium-heat appliances. F.11.3.5 Clearance. Concrete and masonry chim-
F.11.2.1 General. Concrete and masonry chimneys neys for high-heat appliances shall have approved
for medium-heat appliances shall comply with clearance from buildings and structures to prevent
Sections F1 through F5. overheating combustible materials, permit
inspection and maintenance operations on the
F.11.2.2 Construction. Chimneys for medium-heat chimney and prevent danger of burns to persons.
appliances shall be constructed of solid masonry
units or of concrete with walls not less than 200 F.12—Clay flue lining (installation)
mm thick, or with stone masonry not less than 300 Clay flue liners shall be installed in accordance
mm thick with ASTM C 1283 and extend from a point not
F.11.2.3 Lining. Concrete and masonry chimneys less than 203 mm below the lowest inlet or, in the
shall be lined with an approved medium-duty case of fireplaces, from the top of the smoke
refractory brick not less than 110 mm thick laid on chamber to a point above the enclosing walls. The
the 110 mm in an approved medium-duty lining shall be carried up vertically, with a
refractory mortar. The lining shall start 600 mm or maximum slope no greater than 30 degrees (0.52
more below the lowest chimney connector rad) from the vertical.
entrance. Chimneys terminating 7500 mm or less Clay flue liners shall be laid in medium-duty non
above a chimney connector entrance shall be lined water-soluble refractory mortar conforming to
to the top. ASTM C 199 with tight mortar joints left smooth
F.11.2.4 Multiple passageway. Concrete and on the inside and installed to maintain an airspace
masonry chimneys containing more than one or insulation not to exceed the thickness of the flue
passageway shall have the liners separated by a liner separating the flue liners from the interior
minimum 100 mm concrete or solid masonry wall. face of the chimney masonry walls. Flue lining
shall be supported on all sides. Only enough
F.11.2.5 Termination height. Concrete and
mortar shall be placed to make the joint and hold
masonry chimneys for medium-heat appliances
the liners in position.
shall extend not less than 3000 mm higher than
any portion of any building within 7500 mm. F.13—Additional requirements
F.11.2.6 Clearance. A minimum clearance of 100 F.13.1 Listed materials. Listed materials used as
mm shall be provided between the exterior flue linings shall be installed in accordance with
surfaces of a concrete or masonry chimney for the terms of their listings and the manufacturer's
medium-heat appliances and combustible material. instructions.
F.11.3 Concrete and masonry chimneys for high- F.13.2 Space around lining. The space
heat appliances. surrounding a chimney lining system or vent
F.11.3.1 General. Concrete and masonry chimneys installed within a masonry chimney shall not be
for high-heat appliances shall comply with used to vent any other appliance.
Sections F1 through F5. Exception: This shall not prevent the installation
F.11.3.2 Construction. Chimneys for high-heat of a separate flue lining in accordance with the
appliances shall be constructed with double walls manufacturer's instructions.
of solid masonry units or of concrete, each wall to F.14—Multiple flues
be not less than 200 mm thick with a minimum air-
space of 50 mm between the walls. When two or more flues are located in the same
chimney, masonry wythes shall be built between
F.11.3.3 Lining. The inside of the interior wall adjacent flue linings. The masonry wythes shall be
shall be lined with an approved high-duty at least 100 mm thick and bonded into the walls of
refractory brick, not less than 110 mm thick laid the chimney.
on the 110 mm in an approved high-duty
refractory mortar. The lining shall start at the base Exception: When venting only one appliance, two
of the chimney and extend continuously to the top. flues are permitted to adjoin each other in the same
chimney with only the flue lining separation

SBC 305-CR- 11
 APPENDIX F—MASONRY

between them. The joints of the adjacent flue F.18—Masonry chimney cleanout
linings shall be staggered not less than 100 mm.
openings
F.15—Flue area (appliance) Cleanout openings shall be provided within 150
Chimney flues shall not be smaller in area than the mm of the base of each flue within every masonry
area of the connector from the appliance. Chimney chimney. The upper edge of the cleanout shall be
flues connected to more than one appliance shall located not less than 150 mm below the lowest
be not less than the area of the largest connector chimney inlet opening. The height of the opening
plus shall be not less than 150 mm. The cleanout shall
50 percent of the areas of additional chimney be provided with a noncombustible cover.
connectors. Exception: Chimney flues serving masonry
Exceptions: fireplaces, where cleaning is possible through the
fireplace opening.
(1) Chimney flues serving oil-fired
appliances sized in accordance with F.19—Chimney clearances
NFPA 31.
Any portion of a masonry chimney located in the
(2) Chimney flues serving gas-fired interior of the building or within the exterior wall
appliances sized in of the building shall have a minimum airspace
accordance with the International Fuel clearance to combustibles of 50 mm. Chimneys
Gas Code. located entirely outside the exterior walls of the
building, including chimneys that pass through the
F.16—Flue area (masonry fireplace).
soffit or cornice, shall have a minimum airspace
Flue sizing for chimneys serving fireplaces shall clearance of 25 mm. The airspace shall not be
be in accordance with Section F.16.1 or F.16.2. filled, except to provide fire blocking in
accordance with Section F20.
F.16.1 Minimum area. Round chimney flues shall
have a minimum net cross-sectional area of not Exceptions:
less than 1/12 of the fireplace opening. Square
(1) Masonry chimneys equipped with a
chimney flues shall have a minimum net cross-
chimney lining system listed and labeled
sectional area of not less than 1/10 of the fireplace for use in chimneys in contact with
opening. Rectangular chimney flues with an aspect combustibles in accordance with UL
ratio less than 2 to 1 shall have a minimum net 1777, and installed in accordance with the
cross-sectional area of not less than 1/10 of the manufacturer's instructions, are permitted
fireplace opening. Rectangular chimney flues with to have combustible material in contact
an aspect ratio of 2 to 1 or more shall have a with their exterior surfaces.
minimum net cross- sectional area of not less than
1/8 of the fireplace opening. (2) Where masonry chimneys are constructed
as part of masonry or concrete walls,
F.16.2 Determination of minimum area. The combustible materials shall not be in
mini- mum net cross-sectional area of the flue contact with the masonry or concrete wall
shall be determined in accordance with Figure F.1. less than 300 mm from the inside surface
A flue size providing not less than the equivalent of the nearest flue lining.
net cross- sectional area shall be used. Cross-
sectional areas of clay flue linings are as provided (3) Exposed combustible trim and the edges
in Table F.1 and Table F.2 or as provided by the of sheathing materials, such as wood
manufacturer or as measured in the field. The siding, are permitted to abut the masonry
height of the chimney shall be measured from the chimney sidewalls, in accordance with
firebox floor to the top of the chimney flue. Figure F.2, provided such combustible
trim or sheathing is not less than 300 mm
F.17—Inlet from the inside surface of the nearest flue
Inlets to masonry chimneys shall enter from the lining. Combustible material and trim
side. Inlets shall have a thimble of fireclay, rigid shall not overlap the corners of the
refractory material or metal that will prevent the chimney by more than 25 mm.
connector from pulling out of the inlet or from F.20—Chimney fire blocking
extending beyond the wall of the liner.

SBC 305-CR- 11
 APPENDIX F—MASONRY

All spaces between chimneys and floors and between wood joists, beams or headers shall be
ceilings through which chimneys pass shall be fire self- supporting or be placed on strips of metal or
blocked with noncombustible material securely metal lath laid across the spaces between
fastened in place. The fire blocking of spaces combustible material and the chimney.

SBC 305-CR- 11
APPENDIX F—MASONRY

TABLES AND FIGURES OF APPENDIX F

Table F.1: Net cross-sectional area of round flue sizesa

FLUE SIZE, INSIDE DIAMETER CROSS-SECTIONAL AREA
(mm) (mm2)
150 17670
175 24050
200 31415
250 49090
269 56830
300 70685
375 110445
450 159045
a
Flue sizes are based on ASTM C 315.

Table F.2: Net cross-sectional area of square and rectangular flue sizes
FLUE SIZE, OUTSIDE NOMINAL CROSS-SECTIONAL AREA
DIMENSIONS (mm) (mm2)

114 × 216 14838

114 × 330 21935
203 × 203 27096
216 × 216 31613
203 × 305 43226
216 × 330 49032
305 × 305 65806
216 × 457 65161
330 × 330 81991
305 × 406 84516
330 × 457 111613
406 × 406 116774
406 × 508 143225
457 × 457 150322
508 × 508 192258
508 × 609 216129
609 × 609 278063

SBC 305-CR- 11
APPENDIX F—MASONRY

Figure F.1: Flue sizes for masonry chimneys

Figure F.2: Illustration of exception three chimney clearance provision

SBC 305-CR- 11