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ANSI/AISC 341-10
An American National Standard
Seismic Provisions for
Structural Steel Buildings
June 22, 2010
Supersedes the
Seismic Provisions for Structural Steel Buildings
dated March 9, 2005,
Supplement No. 1 dated November 16, 2005,
and all previous versions
Approved by the AISC Committee on Specifications
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
One East Wacker Drive, Suite 700
Chicago, Illinois 60601-1802
Final _SeismicProvisions Spec._September 10, 2012 10/09/12 2:05 PM Page ii
Copyright © 2010
by
American Institute of Steel Construction
All rights reserved. This book or any part thereof
must not be reproduced in any form without the
written permission of the publisher.
The AISC logo is a registered trademark of AISC.
The information presented in this publication has been prepared in accordance with recog-
nized engineering principles and is for general information only. While it is believed to be
accurate, this information should not be used or relied upon for any specific application
without competent professional examination and verification of its accuracy, suitability and
applicability by a licensed professional engineer, designer or architect. The publication of
the material contained herein is not intended as a representation or warranty on the part of
the American Institute of Steel Construction or of any other person named herein, that this
information is suitable for any general or particular use or of freedom from infringement of
any patent or patents. Anyone making use of this information assumes all liability arising
from such use.
Caution must be exercised when relying upon other specifications and codes developed by
other bodies and incorporated by reference herein since such material may be modified or
amended from time to time subsequent to the printing of this edition. The Institute bears no
responsibility for such material other than to refer to it and incorporate it by reference at the
time of the initial publication of this edition.
Printed in the United States of America
First Printing: September 2011
Second Printing: January 2012
Third Printing: September 2012
Seismic Provisions for Structural Steel Buildings, June 22, 2010
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9.1–iii
PREFACE
This Preface is not a part of ANSI/AISC 341-10, Seismic Provisions for Structural Steel
Buildings, but is included for informational purposes only.
The AISCSpecification for Structural Steel Buildings(ANSI/AISC 360-10) is intended
to cover common design criteria. Accordingly, it is not feasible for it to also cover all of the
special and unique problems encountered within the full range of structural design practice.
This document, the AISC Seismic Provisions for Structural Steel Buildings (ANSI/AISC
341-10) (hereafter referred to as the Provisions) is a separate consensus standard that
addresses one such topic: the design and construction of structural steel and composite
structural steel/reinforced concrete building systems for high-seismic applications.
A list of Symbols and a Glossary are part of this document. Terms that appear in the
Glossary are generally italicized where they first appear in a sub-section, throughout these
Provisions. A nonmandatory Commentary with background information is also provided.
Nonmandatory user notes are interspersed throughout these Provisionsto provide guidance
on the application of the document.
This edition of the AISC Seismic Provisions for Structural Steel Buildingswas developed
in concert with both ANSI/AISC 360-10 and ASCE/SEI 7-10, Minimum Design Loads for
Buildings and Other Structures.This will allow these Provisions to be incorporated by ref-
erence into the 2012 IBC, which will use ASCE/SEI 7-10 as its basis of design for loadings.
Some of the most significant modifications to this edition of these Provisionsare related
to format. The organization of the chapters has been changed to be more consistent with that
of ANSI/AISC 360-10. In the 2005 edition, these Provisionsseparated the requirements for
structural steel buildings from that of composite structural steel/reinforced concrete con-
struction into two parts. In this edition of the Provisions, Part I and Part II have been
combined into one document. In addition, each structural system is presented in a unified
manner with parallel headings that will ease comparison of requirements between systems
and application of the document. A Cross Reference listing is provided comparing the 2010
to the 2005 version of the Provisions.
A number of significant technical modifications have also been made since the 2005 edi-
tion of these Provisions, including the following:
• Clarifying the intended combination of this document with the provisions of ACI 318
for composite construction systems
• Establishing a new chapter on analysis requirements that applies to all systems
• Adding terms to clearly identify the level of ductile response capable of various mem-
bers in the seismic force resisting system (SFRS)
• Adding language to clarify the design of members and connections that are not part of
the SFRS for deformation compatibility
• Including a discussion of the “Basis of Design” that explains the intended seismic
response characteristics of each structural system
• Improving the consistency, clarity and completeness of how each structural system
treats all aspects of the seismic design and detailing
• Adding requirements for two cantilever column systems to be consistent with other
systems in these Provisions and the seismic design parameters ASCE/SEI 7-10
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9.1–iv PREFACE
• Adding analysis requirements to address the inelastic response of special concentri-
cally braced frames
• Modifying the connection requirements for braced frame systems to ensure that the
expected deformation demands can be accommodated
• Adding requirements for the use of box-shaped link beams in eccentrically braced
frames
• Adding requirements for the use of perforated plates in special plate shear walls
• Significantly increasing the detail for the design requirements of composite systems,
such that they are consistent with structural steel systems
• Incorporating AWS D1.8/D1.8M by reference for welding related issues
The AISC Committee on Specifications, Task Committee 9—Seismic Design is respon-
sible for the ongoing development of these Provisions. The AISC Committee on
Specifications gives final approval of the document through an ANSI-accredited balloting
process, and has enhanced these Provisions through careful scrutiny, discussion and sug-
gestions for improvement. The contributions of these two groups, comprising well more
than 80 structural engineers with experience from throughout the structural steel industry, is
gratefully acknowledged. AISC further acknowledges the significant contributions of sev-
eral groups to the completion of this document: the Building Seismic Safety Council
(BSSC), the Federal Emergency Management Agency (FEMA), the National Science
Foundation (NSF), and the Structural Engineers Association of California (SEAOC).
The reader is cautioned that professional judgment must be exercised when data or rec-
ommendations in these provisions are applied, as described more fully in the disclaimer
notice preceding the Preface.
This specification was approved by the AISC Committee on Specifications:
James M. Fisher, Chairman Mark V. Holland
Edward E. Garvin, Vice Chairman Ronald J. Janowiak
Hansraj G. Ashar Richard C. Kaehler
William F. Baker Lawrence A. Kloiber
John M. Barsom Lawrence F. Kruth
William D. Bast Jay W. Larson
Reidar Bjorhovde Roberto T. Leon
Roger L. Brockenbrough James O. Malley
Gregory G. Deierlein Sanjeev R. Malushte
Bruce R. Ellingwood David L. McKenzie
Michael D. Engelhardt Duane K. Miller
Shu-Jin Fang Larry S. Muir
Steven J. Fenves Thomas M. Murray
John W. Fisher R. Shankar Nair
Theodore V. Galambos Jack E. Petersen
Louis F. Geschwindner Douglas A. Rees-Evans
Lawrence G. Griffis Thomas A. Sabol
John L. Gross Robert E. Shaw, Jr.
Jerome F. Hajjar Donald R. Sherman
Patrick M. Hassett W. Lee Shoemaker
Tony C. Hazel William A. Thornton
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PREFACE 9.1–v
Raymond H.R. Tide Donald W. White
Chia-Ming Uang Cynthia J. Duncan, Secretary
The Committee gratefully acknowledges the following task committee (TC 9—Seismic
Design) for their development of this document.
James O. Malley, Chairman Roberto T. Leon
C. Mark Saunders, Vice Chairman Sanjeev R. Malushte
Michel Bruneau Bonnie E. Manley
Gregory G. Deierlein Clarkson W. Pinkham
Richard M. Drake John A. Rolfes
Michael D. Engelhardt Rafael Sabelli
Timothy P. Fraser Thomas A. Sabol
Subhash C. Goel Bahram M. Shahrooz
Jerome F. Hajjar Robert E. Shaw, Jr.
Ronald O. Hamburger W. Lee Shoemaker
James R. Harris Kurt D. Swensson
Patrick M. Hassett Robert Tremblay
John D. Hooper Jamie Winans
Brian T. Knight Cynthia J. Duncan, Secretary
Keith Landwehr Leigh Arber, Secretary
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9.1–vi
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9.1–vii
TABLE OF CONTENTS
CROSS REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–xxix
SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–xxxiii
GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–xxxix
ACRONYMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–xlv
PROVISIONS
A. GENERAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–1
A1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–1
A2. Referenced Specifications, Codes and Standards . . . . . . . . . . . . . . . . . . . .9.1–2
A3. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–2
1. Material Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–2
2. Expected Material Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–3
3. Heavy Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–5
4. Consumables for Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–5
4a. Seismic Force Resisting System Welds . . . . . . . . . . . . . . . . . . . . . . .9.1–5
4b. Demand Critical Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–5
5. Concrete and Steel Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–6
A4. Structural Design Drawings and Specifications . . . . . . . . . . . . . . . . . . . . .9.1–6
1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–6
2. Steel Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–6
3. Composite Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–7
B. GENERAL DESIGN REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–8
B1. General Seismic Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–8
B2. Loads and Load Combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–8
B3. Design Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–9
1. Required Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–9
2. Available Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–9
B4. System Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–9
C. ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–10
C1. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–10
C2. Additional Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–10
C3. Nonlinear Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–10
D. GENERAL MEMBER AND CONNECTION DESIGN
REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–11
D1. Member Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–11
1. Classification of Sections for Ductility . . . . . . . . . . . . . . . . . . . . . . .9.1–11
1a. Section Requirements for Ductile Members . . . . . . . . . . . . . . . . . . .9.1–11
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1b. Width-to-Thickness Limitations of Steel and
Composite Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–11
2. Stability Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–14
2a. Moderately Ductile Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–14
2b. Highly Ductile Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–15
2c. Special Bracing at Plastic Hinge Locations . . . . . . . . . . . . . . . . . . .9.1–15
3. Protected Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–16
4. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–16
4a. Required Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–16
4b. Encased Composite Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–17
4c. Filled Composite Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–19
5. Composite Slab Diaphragms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–19
5a. Load Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–19
5b. Nominal Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–19
D2. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–20
1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–20
2. Bolted Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–20
3. Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–21
4. Continuity Plates and Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–21
5. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–21
5a. Location of Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–21
5b. Required Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–21
5c. Required Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–22
5d. Structural Steel Splice Configurations . . . . . . . . . . . . . . . . . . . . . . .9.1–22
5e. Splices in Encased Composite Columns . . . . . . . . . . . . . . . . . . . . . .9.1–22
6. Column Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–22
6a. Required Axial Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–23
6b. Required Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–23
6c. Required Flexural Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–24
7. Composite Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–24
8. Steel Anchors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–26
D3. Deformation Compatibility of Non-SFRS Members
and Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–26
D4. H-Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–26
1. Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–26
2. Battered H-Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–26
3. Tension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–26
4. Protected Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–27
E. MOMENT-FRAME SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
E1. Ordinary Moment Frames (OMF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
2. Basis of Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
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4. System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
5. Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
5a. Basic Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
5b. Protected Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–28
6. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–29
6a. Demand Critical Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–29
6b. FR Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–29
6c. PR Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–30
E2. Intermediate Moment Frames (IMF) . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–30
1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–30
2. Basis of Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
4. System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
4a. Stability Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
5. Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
5a. Basic Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
5b. Beam Flanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–31
5c. Protected Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–32
6. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–32
6a. Demand Critical Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–32
6b. Beam-to-Column Connection Requirements . . . . . . . . . . . . . . . . . .9.1–32
6c. Conformance Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–33
6d. Required Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–33
6e. Panel Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–33
6f. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
6g. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
E3. Special Moment Frames (SMF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
2. Basis of Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
4. System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
4a. Moment Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–34
4b. Stability Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–36
4c. Stability Bracing at Beam-to-Column Connections . . . . . . . . . . . . .9.1–37
5. Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–38
5a. Basic Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–38
5b. Beam Flanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–38
5c. Protected Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–38
6. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–38
6a. Demand Critical Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–38
6b. Beam-to-Column Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–39
6c. Conformance Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–39
6d. Required Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–40
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9.1–x TABLE OF CONTENTS
6e. Panel Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–40
6f. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–41
6g. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–43
E4. Special Truss Moment Frames (STMF) . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–43
1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–43
2. Basis of Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–43
3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–43
3a. Special Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–43
3b. Nonspecial Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–44
4. System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–44
4a. Special Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–44
4b. Stability Bracing of Trusses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–44
4c. Stability Bracing of Truss-to-Column Connections . . . . . . . . . . . . .9.1–45
4d. Stiffness of Stability Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–45
5. Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–45
5a. Special Segment Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–45
5b. Expected Vertical Shear Strength of Special Segment . . . . . . . . . . .9.1–45
5c. Width-to-Thickness Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–46
5d. Built-Up Chord Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–46
5e. Protected Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–46
6. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–46
6a. Demand Critical Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–46
6b. Connections of Diagonal Web Members in the
Special Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
6c. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
E5. Ordinary Cantilever Column Systems (OCCS) . . . . . . . . . . . . . . . . . . . .9.1–47
1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
2. Basis of Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
4. System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
4a. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
4b. Stability Bracing of Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
5. Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
5a. Basic Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–47
5b. Column Flanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
5c. Protected Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
6. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
6a. Demand Critical Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
6b. Column Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
E6. Special Cantilever Column Systems (SCCS) . . . . . . . . . . . . . . . . . . . . . .9.1–48
1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
2. Basis of Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1–48
Seismic Provisions for Structural Steel Buildings, June 22, 2010
AMERICANINSTITUTEOFSTEELCONSTRUCTION
Description:This Preface is not a part of ANSI/AISC 341-10, Seismic Provisions for This document, the AISC Seismic Provisions for Structural Steel Buildings
