NIST GCR 10-917-4
NEHRP Seismic Design Technical Brief No. 3
Seismic Design of Cast-in-Place
Concrete Diaphragms,
Chords, and Collectors
A Guide for Practicing Engineers
Jack P. Moehle
John D. Hooper
Dominic J. Kelly
Thomas R. Meyer
NEHRP Seismic Design
Technical Briefs
NEHRP (National Earthquake Hazards Reduction Program) Technical Dominic J. Kelly, P.E., S.E., is an Associate Principal of Simpson
Briefs are published by NIST, the National Institute of Standards and Gumpertz & Heger Inc. in Waltham, MA where he designs, rehabilitates,
Technology, as aids to the efficient transfer of NEHRP and other and investigates building and non-building structures. He is a Fellow of
research into practice, thereby helping to reduce the nation’s losses the American Concrete Institute, and has served on ACI Code Committee
from earthquakes. 318 since 2003. He has served as a member of the Seismic Code
Committee of ASCE 7 since 2000.
National Institute of
Standards and Technology Thomas R. Meyer, S.E. is a structural engineer and associate of
The National Institute of Standards and Technology (NIST) is a federal Magnussen Klemencic Associates, a structural and civil engineering
technology agency within the U.S. Department of Commerce that firm headquartered in Seattle, Washington. He is the firm’s in-house
promotes U.S. innovation and industrial competitiveness by advancing diaphragm specialist, and has experience designing a number of building
measurement science, standards, and technology in ways that enhance types including high-rise residential towers, museums, performing arts
economic security and improve our quality of life. It is the lead agency centers, and higher education facilities.
of the National Earthquake Hazards Reduction Program (NEHRP). Dr.
John (Jack) R. Hayes is the Director of NEHRP, within NIST’s Building About the Review Panel
and Fire Research Laboratory (BFRL). Dr. Jeffrey J. Dragovich managed The contributions of the three review panelists for this publication are
the project for BFRL. gratefully acknowledged.
NEHRP Consultants Joint Venture S. K. Ghosh, Ph.D. is President, S. K. Ghosh Associates, Inc., Palatine,
This NIST-funded publication is one of the products of the work of IL and Aliso Viejo, CA. He and the firm specialize in seismic and building
the NEHRP Consultants Joint Venture carried out under Contract code consulting. He is a Fellow of the American Concrete Institute and
SB 134107CQ0019, Task Order 69188. The partners in the NEHRP serves on ACI Committee 318, the ASCE 7 Committee, and the Seismic
Consultants Joint Venture are the Applied Technology Council (ATC) and Subcommittee of ASCE 7.
the Consortium of Universities for Research in Earthquake Engineering
(CUREE). The members of the Joint Venture Management Committee Rafael Sabelli, P.E., S.E., is Director of Seismic Design at Walter P
are James R. Harris, Robert Reitherman, Christopher Rojahn, and Moore, a structural and civil engineering firm with offices nationwide. He
Andrew Whittaker, and the Program Manager is Jon A. Heintz. Assisting is a member of the Building Seismic Safety Council’s 2014 Provisions
the Program Manager is ATC Senior Management Consultant David A. Update Committee and of the American Society of Civil Engineers
Hutchinson, who on this Technical Brief provided substantial assistance Seismic Subcommittee for ASCE 7-10.
in the development of the content.
Manny Morden, P.E., S.E., MMSE Consulting Structural Engineer, and
Principal with Brandow & Johnston, Inc., in Los Angeles, California, is a
About The Authors consulting structural engineer with extensive reinforced concrete design
Jack P. Moehle, Ph.D., P.E., is Professor of Civil and Environmental experience. He is a Fellow of the Structural Engineers Association
Engineering at the University of California, Berkeley, where he teaches of California and Past President of the Southern California Structural
and conducts research on earthquake-resistant concrete construction. Engineers Association.
He is Fellow of the American Concrete Institute, and has served on
the ACI Code Committee 318 since 1989 and as chair of the seismic
subcommittee since 1995. He is a Fellow of the Structural Engineers
Association of California and Honorary Member of the Structural
Engineers Association of Northern California.
John D. Hooper, P.E., S.E., is Director of Earthquake Engineering at
Magnusson Klemencic Associates, a structural and civil engineering firm
headquartered in Seattle, Washington. He is a member of the Building
Seismic Safety Council’s 2014 Provisions Update Committee and chair
of the American Society of Civil Engineers Seismic Subcommittee for
ASCE 7-10.
Applied Technology Council (ATC) Consortium of Universities for Research in
201 Redwood Shores Parkway - Suite 240 Earthquake Engineering (CUREE)
Redwood City, California 94065 1301 South 46th Street - Building 420
(650) 595-1542 Richmond, CA 94804
www.atcouncil.org email: atc@atcouncil.org (510) 665-3529
www.curee.org email: curee@curee.org
NIST GCR 10-917-4
Seismic Design of
Cast-in-Place Concrete Diaphragms
Chords, and Collectors
A Guide for Practicing Engineers
Prepared for
U.S. Department of Commerce
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899-8600
By
Jack P. Moehle, Ph.D., P.E.
University of California, Berkeley
Berkeley, California
John D, Hooper, P.E., S.E.
Magnusson Klemencic Associates
Seattle, Washington
Dominic J. Kelly, P.E., S.E.
Simpson Gumpertz & Heger Inc.
Waltham, Massachusetts
Thomas R. Meyer, S.E.
Magnusson Klemencic Associates
Seattle, Washington
August 2010
U.S. Department of Commerce
Gary Locke, Secretary
National Institute of Standards and Technology
Patrick Gallagher, Director
Contents
1. Introduction..................................................................................................................1
2. The Roles of Diaphragms...............................................................................................2
3. Diaphragm Components..............................................................................................3
4. Diaphragm Behavior and Design Principles....................................................................4
5. Building Analysis Guidance...........................................................................................7
6. Diaphragm Analysis Guidance....................................................................................11
7. Design Guidance........................................................................................................17
8. Additional Requirements............................................................................................21
9. Detailing & Constructability Issues...............................................................................23
10. References................................................................................................................26
11. Notations and Abbreviations.......................................................................................27
12. Credits.......................................................................................................................29
Disclaimers
The policy of the National Institute of Standards and Technology is to use the International System of Units (metric units) in all of its
publications. However, in North America in the construction and building materials industry, certain non-SI units are so widely used
instead of SI units that it is more practical and less confusing to include measurement values for customary units only.
This publication was produced as part of contract SB134107CQ0019, Task Order 69188 with the National Institute of Standards and
Technology. The contents of this publication do not necessarily reflect the views or policies of the National Institute of Standards and
Technology or the US Government.
This Technical Brief was produced under contract to NIST by the NEHRP Consultants Joint Venture, a joint venture of the Applied
Technology Council (ATC) and the Consortium of Universities for Research in Earthquake Engineering (CUREE). While endeavoring to
provide practical and accurate information in this publication, the NEHRP Consultants Joint Venture, the authors, and the reviewers do
not assume liability for, nor make any expressed or implied warranty with regard to, the use of its information. Users of the information
in this publication assume all liability arising from such use.
Cover photo – Collector spread into slab adjacent to shear wall.
How to Cite This Publication
Moehle, Jack P., Hooper, John D., Kelly, Dominic J., and Meyer, Thomas R. (2010). “Seismic design of cast-in-place concrete diaphragms,
chords, and collectors: a guide for practicing engineers,” NEHRP Seismic Design Technical Brief No. 3, produced by the NEHRP
Consultants Joint Venture, a partnership of the Applied Technology Council and the Consortium of Universities for Research in Earthquake
Engineering, for the National Institute of Standards and Technology, Gaithersburg, MD, NIST GCR 10-917-4.
