North American Standards for
Cold-Formed Steel Framing
Roger LaBoube, Ph.D., P.E.
Curators’ Distinguished Teaching Professor Emeritus
Director, Wei-Wen Yu Center for Cold-Formed Steel Structures
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COFS Mission
• To eliminate regulatory barriers and
increase the reliability and cost
competitiveness of cold-formed steel
framing in residential and light commercial
building construction through improved
design and installation standards.
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Member versus System Design
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AISI Standards Hierarchy
General Provisions
Requirements for
Specification engineered or
prescriptive design
Design Standards
Prescriptive Methods
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Framing Standards
www.aisistandards.org
• Existing Standards:
– AISI S200: General Provisions *
– AISI S201: Product Standard *
– AISI S202: Code of Standard Practice
– AISI S210: Floor and Roof System Design *
– AISI S211: Wall Stud Design *
– AISI S212: Header Design *
– AISI S213: Lateral Design *
– AISI S214: Truss Design *
– AISI S230: Prescriptive Method for One and Two
Family Dwellings
* North American Standard 1-5
AISI Framing Standards
• General:
– AISI S200: General Provisions
– AISI S201: Product Standard
– AISI S202: Code of Standard Practice
• Design Standards:
– AISI S210: Floor and Roof System Design
– AISI S211: Wall Stud Design
– AISI S212: Header Design
– AISI S213: Lateral Design
– AISI S214: Truss Design
• Prescriptive Methods:
– AISI S230: Prescriptive Method for One and Two Family
Dwellings
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AISI S200: General Provisions
A. GENERAL
B. MEMBER DESIGN
C. INSTALLATION
D. CONNECTIONS
E. MISCELLANEOUS
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Member Design
• Member design is to be in accordance with AISI
S100: Specification
• Members shall be in good condition
• Damaged members to be replaced/repaired
• Not permitted without approved design:
– Web holes
– Cutting or notching of flanges or lips
– Splicing
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Installation Tolerances
• Foundation:
– Uniform bearing surface with maximum 1/4” gap
between the track and foundation
• Ground Contact:
– Avoid direct contact with the ground and provide
sufficient height above ground
• Framing:
– Install plumb and level, spacing not to exceed span
capacity of sheathing, bearing requirements
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Installation Tolerances
• Floor joist web must not be in contact with
rim joist web to prevent squeaks
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Installation Tolerances
• Wall stud must be seated in track with
maximum gap of 1/8”
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Screw Connections
• Installation:
– Minimum of 3 exposed threads
– No permanent separation between plies
Minimum 3 exposed
threads shall protrude
through steel
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Screw Connections
• Stripped Screws:
– Stripped screw fasteners in direct tension are
considered ineffective
– Stripped screw fasteners in shear may be
considered effective (not more than 25% of
the total number considered effective)
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Screw Connections
• Spacing:
– Provides for an allowance if the spacing is
less than 3 times screw diameter, as
specified by AISI S100: Specification
– If spacing is greater than 2 times screw
diameter, screws can be considered
80% effective
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In-Line Framing
• No restriction
existed that
specifically
addresses the case
where the bearing
stiffener is attached
to the back side of
the floor joist
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In-Line Framing
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AISI S201: Product Data
A. GENERAL
B. MATERIALS
C. PRODUCTS
D. QUALITY
ASSURANCE
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Shapes
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Shapes
S = C-shaped stud or joist
T = Track
U = Cold rolled channel
F = Furring (hat) channel
L = Angle or L-header
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Product Designator
600 S 162 - 54
2 or 3 digit numeral indicating base metal
thickness in 1/1000 inch (mils) (0.054”)
3 digit numeral indicating flange width in 1/100
inches (1-5/8”), followed by a dash
Letter indicating the type of product (C-shape section)
3 or 4 digit numeral indicating web depth in 1/100 inches (6”)
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AISI S202: Code of Standard
Practice
A. GENERAL
B. CLASSIFICATION OF
MATERIALS
C. CONTRACT
DOCUMENTS
D. INSTALLATION
DRAWINGS
E. MATERIALS
F. INSTALLATION
G. QUALITY CONTROL
H. CONTRACTUAL
RELATIONS
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Scope
• Defines and sets forth accepted norms of
good practice for fabrication and
installation of cold-formed steel structural
framing
• Supplement to legal building regulation
• Would be used unless differing instructions
in the contract documents
• Voluntary document
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Example
• Responsibilities for
field modifications
and repairs must be
clearly defined and
communicated
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AISI S210: Floor and Roof System
Design
• Load Combinations
• Member Design:
– Discretely Braced Design
– Continuously Braced Design
• Connection Design:
– Bearing Stiffeners
• Bracing Design
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Member Design
• Discretely braced design:
– Neglect attached sheathings
– Discrete braces provided along member
length
• Continuously braced design:
– Sheathing or deck attached to
compression side
– Continuous or discrete bracing attached to
tension side
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Bracing Design
• Provides a “prescriptive” approach for
compression side bracing:
– 3/8 inch wood structural sheathing or 9/16” x 0.0269”
thickness steel deck
– attached with No. 8 screws at 12 inches o.c.
• Adapts requirements for tension side bracing
from AISI S100 (Specification) requirements for
members where neither flange is attached to
sheathing
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AISI S211: Wall Stud Design
• Load Combinations
• Sheathing Braced Design
• Stud-to-Track Connection
• Deflection Track Connection
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Wall Stud Design
• All-steel design:
– Neglect attached sheathings
• Sheathing braced design:
– Sheathing attached to flanges
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Stud-to-Track Connection
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Single Deflection Track
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Deflection Track Connection
wdt
θ θ e
Track
Stud
bstud
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AISI S212: Header Design
A. GENERAL
B. DESIGN
C. INSTALLATION
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Back-to-Back Headers
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Back-to-Back Headers
• Moment Capacity:
– Specification C3.1.1 for C-sections alone
• Shear and Web Crippling Capacity:
– Shear Capacity C3.2
– Web Crippling Capacity:
– Specification C3.4 for I-sections
• Bending and Web Crippling:
– Specification C3.5 for I-sections
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Box Headers
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Box Headers
• Moment Capacity:
– Specification C3.1.1 for C-sections alone
• Shear Capacity:
– Specification C3.2
• Web Crippling Capacity:
– Specification C3.4 for single-web sections
– Modification is permitted to recognize
presence of the track
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L-Headers
Double L-Header
Single L-Header
Inverted L-Header
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AISI S213: Lateral Design
• Type 1 Shear Walls
• Type 2 Shear Walls
• Diagonal Strap Bracing
• Wall Anchorage
• Diaphragms
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Type 1 Shear Walls
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Type 1 Shear Walls
2
8vh 3
vh v
δ= + ω1ω 2 + ω1 ω 2ω 3ω 4
5/ 4
+ δ a
E s Ac b ρGt sheathing β 1-40
Type 2 Shear Walls
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Diaphragms
• Design Values for Wood Structural Panel
Sheathing
• Design Deflections
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AISI S214: Truss Design
A. GENERAL
B. DESIGN
RESPONSIBILITIES
C. Reserved
D. TRUSS DESIGN
E. QUALITY CRITERIA
F. TRUSS
INSTALLATION
G. TEST METHODS
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Confirmatory Truss Test
Top Chord Supported
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AISI S230: Prescriptive Method
A. GENERAL
B. CONNECTIONS
C. FOUNDATION
D. FLOOR FRAMING
E. WALL FRAMING
F. ROOF FRAMING
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Tables and Details
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Available AISI Design Aids
https://shop.steel.org/c/34/steel-framing-alliance
• AISI D100, Cold-Formed Steel Design Manual
• AISI D110, Cold-Formed Steel Framing Design
Guide
• AISI D111, Cold-Formed Steel Purlin Roof
Framing Systems (being updated)
• AISI D112, Brick Veneer Cold-Formed Steel
Framing Design Guide
• AISI D113, Design Guide for Cold-Formed Steel
Framed Shear Wall Assemblies (being updated)
40+ Existing Technical Notes
http://www.cfsei.org/technical-publications
• D001-13, Durability of CFS Framing Members • G802-13, AISI Section A2.2 - Other Steels
• D100-13, Corrosion Protection of Fasteners • G900-15, Design Methodology for Hole Reinforcement of
• D200-12, Corrosion Protection for CFS Framing in Coastal CFS Bending Members
Areas • J100-11, CFS Floor Joists
• F100-09, Design of Clip Angle Bearing Stiffeners • L001-10, Design of Diagonal Strap Bracing Lateral Force
• F101-12, Screws for Attachment of Steel-To-Wood and Resisting Systems for the 2006 IBC
Wood-Steel • L200-09, Roof Framing Anchorage Forces: MWFRS or C&C
• F102-11, Screw Fastener Selection • L202-12, Diaphragm Design with Pneumatically Driven
• F140-10, Welding CFS Pins
• F300-09, Pneumatically Driven Pins for Wood-Based Panel • L300-09, Design of End Posts for Diaphragm Shear Walls
Attachment • S100-16, Antiterrorism Design Requirements for CFS
• F501-11, CFS Truss to Bearing Connections Framing
• F701-12, Evaluation of Screw Strength Capacity • T001-09, Fire and Acoustic-Rated Assemblies for Multi-
• G000-08, CFS Design Software Unit Structures
• G100-07, Using Chapter F of the NA Specification for the • T100-12, Fire-Rated Assemblies for CFS Construction
Design of CFS Structural Members • W100-08a, Single Slip Track Design
• G101-08, Design Aids & Examples for Distortional Buckling • W101-09, Common Design Issues for Deflection Track
• G102-09, Designing CFS using the Direct Strength Method • W102-12, Introduction to Curtain Wall Design Using CFS
• G103-11a, Tabulated Local and Distortional Elastic Buckling • W103-11, Design of By-Pass Slip Connectors in CFS
Solutions for Standard Shapes Construction
• G104-14, Welded Boxed-Beam Design • W104-10, Top Track Load Distribution Members
• G200-15, Chase the Loads - Load Path Considerations for • W105-13, Design of Nonstructural Members
CFS Light-Frame Construction • W106-16, Design for Splicing of CFS Wall Studs
• G500-11, Guidelines for Inspecting CFS Structural Framing • W200-09, Header Design
in Low Rise Buildings • W400-16, Mechanical Bridging and Bridging Anchorage of
• G800-12, ASTM Standards for CFS Axially Loaded CFS Studs
• G801-13, ASTM A1003 - No Cause for Rejection • W500-12, Construction Bracing for Walls
Wei-Wen Yu
Center for Cold-Formed Steel Structure
laboube@mst.edu, 573-341-4481
QUESTIONS?
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