Tài liệu Aisc specification for steel building

P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 ANSI/AISC 360-05 An American National Standard Specification for Structural Steel Buildings March 9, 2005 Supersedes the Load and Resistance Factor Design Specification for Structural Steel Buildings dated December 27, 1999, the Specification for Structural Steel Buldings— Allowable Stress Design and Plastic Design dated June 1, 1989, including Supplement No. 1, the Specification for Allowable Stress Design of Single-Angle Members dated June 1, 1989, the Load and Resistance Factor Design Specification for SingleAngle Members dated November 10, 2000, and the Load and Resistance Factor Design Specification for the Design of Steel Hollow Structural Sections dated November 10, 2000, and all previous versions of these specifications. Approved by the AISC Committee on Specifications and issued by the AISC Board of Directors AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. One East Wacker Drive, Suite 700 Chicago, Illinois 60601-1802 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 c 2005 Copyright
by American Institute of Steel Construction, Inc. All rights reserved. This book or any part thereof must not be reproduced in any form without the written permission of the publisher. The information presented in this publication has been prepared in accordance with recognized 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 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 DEDICATION Professor Lynn S. Beedle This edition of the AISC Specification is dedicated to the memory of Dr. Lynn S. Beedle, University Distinguished Professor at Lehigh University. Dr. Beedle served as a faculty member at Lehigh University for 41 years and won a very large number of professional and educational awards, including the 1973 T.R. Higgins Award and the 2003 Geerhard Haaijer Award from AISC. He was a major contributor to several editions of the AISC Specification and a long-time member of the AISC Committee on Specifications. He was instrumental in the development of plastic design methodologies and its implementation into the AISC Specification. He was Director of the Structural Stability Research Council for 25 years, and in that role fostered understanding of various stability problems and helped develop rational design provisions, many of which were adopted in the AISC Specifications. In 1969, he founded the Council on Tall Buildings and Urban Habitat and succeeded in bringing together the disciplines of architecture, structural engineering, construction, environment, sociology and politics, which underlie every major tall building project. He was actively involved in this effort until his death in late 2003 at the age of 85. His contributions to the design and construction of steel buildings will long be remembered by AISC, the steel industry and the structural engineering profession worldwide. For a more complete discussion of Dr. Beedle’s life and accomplishments, see Catalyst for Skyscraper Revolution: Lynn S. Beedle—A Legend in his Lifetime by Mir Ali, published by the Council on Tall Buildings and Urban Habitat (2004). Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. iii P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 iv Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 v PREFACE (This Preface is not part of ANSI/AISC 360-05, Specification for Structural Steel Buildings, but is included for informational purposes only.) This Specification has been based upon past successful usage, advances in the state of knowledge, and changes in design practice. The 2005 American Institute of Steel Construction’s Specification for Structural Steel Buildings for the first time provides an integrated treatment of Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD), and thus combines and replaces earlier Specifications that treated the two design methods separately. As indicated in Chapter B of the Specification, designs can be made according to either ASD or LRFD provisions. This Specification has been developed as a consensus document to provide a uniform practice in the design of steel-framed buildings and other structures. The intention is to provide design criteria for routine use and not to provide specific criteria for infrequently encountered problems, which occur in the full range of structural design. This Specification is the result of the consensus deliberations of a committee of structural engineers with wide experience and high professional standing, representing a wide geographical distribution throughout the United States. The committee includes approximately equal numbers of engineers in private practice and code agencies, engineers involved in research and teaching, and engineers employed by steel fabricating and producing companies. The contributions and assistance of more than 50 additional professional volunteers working in ten task committees are also hereby acknowledged. The Symbols, Glossary and Appendices to this Specification are an integral part of the Specification. A non-mandatory Commentary has been prepared to provide background for the Specification provisions and the user is encouraged to consult it. Additionally, nonmandatory User Notes are interspersed throughout the Specification to provide concise and practical guidance in the application of the provisions. The reader is cautioned that professional judgment must be exercised when data or recommendations in the Specification are applied, as described more fully in the disclaimer notice preceding this Preface. Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 vi 12:16 Char Count= 0 PREFACE This Specification was approved by the Committee on Specifications, James M. Fisher, Chairman Roger E. Ferch, Vice Chairman Hansraj G. Ashar William F. Baker John M. Barsom William D. Bast Reidar Bjorhovde Roger L. Brockenbrough Gregory G. Deierlein Duane S. Ellifritt Bruce R. Ellingwood Michael Engelhardt Shu-Jin Fang Steven J. Fenves John W. Fisher Timothy P. Fraser Theodore V. Galambos Louis F. Geschwindner Lawrence G. Griffis John L. Gross Tony C. Hazel Mark V. Holland Lawrence A. Kloiber Roberto T. Leon Stanley D. Lindsey James O. Malley Richard W. Marshall (deceased) Harry W. Martin David L. McKenzie Duane K. Miller Thomas M. Murray R. Shankar Nair Jack E. Petersen Douglas A. Rees-Evans Robert E. Shaw, Jr. Donald R. Sherman W. Lee Shoemaker William A. Thornton Raymond H. R. Tide Cynthia J. Duncan, Secretary The Committee gratefully acknowledges the following task committee members for their contribution to this document. Farid Alfawakhiri Georges Axmann Joseph Bohinsky Bruce Butler Charles Carter Robert Dexter (deceased) Carol Drucker W. Samuel Easterling Michael Engestrom M. Thomas Ferrell Christopher Foley Arvind Goverdhan Jerome Hajjar Tom Harrington James Harris Steven Herth Todd Helwig Richard Henige Christopher Hewitt Ronald Hiatt Keith Hjelmstad Socrates Ioannides Nestor Iwankiw Richard Kaehler Dean Krouse Barbara Lane Jay Larson Michael Lederle Kevin LeSmith J. Walter Lewis Daniel Linzell LeRoy Lutz Peter Marshall Brian Meacham Saul Mednick James Milke Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 PREFACE Heath Mitchell Jeffrey Packer Frederick Palmer Dhiren Panda Teoman Pekoz Carol Pivonka Clinton Rex John Ruddy David Samuelson Thomas Schlafly James Swanson Emile Troup Chia-Ming Uang Sriramulu Vinnakota Robert Weber Donald White Robert Wills Ronald Ziemian Sergio Zoruba Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. vii P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 viii Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 ix TABLE OF CONTENTS .SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxix xliii SPECIFICATION A. GENERAL PROVISIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Low-Seismic Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. High-Seismic Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Nuclear Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A2. Referenced Specifications, Codes and Standards . . . . . . . . . . . . . . . . A3. Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Structural Steel Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. ASTM Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1b. Unidentified Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1c. Rolled Heavy Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1d. Built-Up Heavy Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Steel Castings and Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Bolts, Washers and Nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Anchor Rods and Threaded Rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Filler Metal and Flux for Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Stud Shear Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A4. Structural Design Drawings and Specifications . . . . . . . . . . . . . . . . . 1 1 2 2 2 2 5 5 6 7 7 7 7 8 8 9 9 9 B. DESIGN REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B2. Loads and Load Combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . B3. Design Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Required Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Limit States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Design for Strength Using Load and Resistance Factor Design (LRFD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Design for Strength Using Allowable Strength Design (ASD) . . . . . 5. Design for Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Design of Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6a. Simple Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6b. Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Design for Serviceability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. Design for Ponding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. Design for Fatigue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. Design for Fire Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Design for Corrosion Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10 10 10 10 11 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 11 11 12 12 12 12 12 13 13 13 13 P1: GIG GRBT055-FM AISC-Sample (LRFD) x June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS 12. Design Wall Thickness for HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13. Gross and Net Area Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . B4. Classification of Sections for Local Buckling . . . . . . . . . . . . . . . . . . 1. Unstiffened Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Stiffened Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B5. Fabrication, Erection and Quality Control . . . . . . . . . . . . . . . . . . . . B6. Evaluation of Existing Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 13 14 14 15 15 18 18 C. STABILITY ANALYSIS AND DESIGN . . . . . . . . . . . . . . . . . . . . . . . . C1. Stability Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Member Stability Design Requirements . . . . . . . . . . . . . . . . . . . . . . . 3. System Stability Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3a. Braced-Frame and Shear-Wall Systems . . . . . . . . . . . . . . . . . . . . . . . 3b. Moment-Frame Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3c. Gravity Framing Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3d. Combined Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C2. Calculation of Required Strengths . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Methods of Second-Order Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. General Second-Order Elastic Analysis . . . . . . . . . . . . . . . . . . . . . . . 1b. Second-Order Analysis by Amplified First-Order Elastic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Design by Second-Order Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Design by First-Order Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 19 19 19 20 20 20 20 20 20 21 21 D. DESIGN OF MEMBERS FOR TENSION . . . . . . . . . . . . . . . . . . . . . . D1. Slenderness Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D2. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D3. Area Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Gross Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Net Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Effective Net Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D4. Built-Up Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D5. Pin-Connected Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Dimensional Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D6. Eyebars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Dimensional Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 26 26 27 27 27 28 28 28 28 30 30 30 30 E. DESIGN OF MEMBERS FOR COMPRESSION . . . . . . . . . . . . . . E1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E2. Slenderness Limitations and Effective Length . . . . . . . . . . . . . . E3. Compressive Strength for Flexural Buckling of Members without Slender Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 32 32 . . . 33 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. . . . . . . 21 23 23 24 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS E4. E5. E6. E7. F. Compressive Strength for Torsional and Flexural-Torsional Buckling of Members without Slender Elements . . . . . . . . . . . . . . . . Single Angle Compression Members . . . . . . . . . . . . . . . . . . . . . . . Built-Up Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Compressive Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Dimensional Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Members with Slender Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Slender Unstiffened Elements, Q s . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Slender Stiffened Elements, Q a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DESIGN OF MEMBERS FOR FLEXURE . . . . . . . . . . . . . . . . . . . . . . F1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F2. Doubly Symmetric Compact I-Shaped Members and Channels Bent about their Major Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F3. Doubly Symmetric I-Shaped Members with Compact Webs and Noncompact or Slender Flanges Bent about Their Major Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Compression Flange Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . F4. Other I-Shaped Members with Compact or Noncompact Webs, Bent about Their Major Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Compression Flange Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Compression Flange Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Tension Flange Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F5. Doubly Symmetric and Singly Symmetric I-Shaped Members with Slender Webs Bent about Their Major Axis . . . . . . . . . . . . . . . . . . . 1. Compression Flange Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Compression Flange Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Tension Flange Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F6. I-Shaped Members and Channels Bent about Their Minor Axis . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Flange Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F7. Square and Rectangular HSS and Box-Shaped Members . . . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Flange Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Web Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F8. Round HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F9. Tees and Double Angles Loaded in the Plane of Symmetry . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. xi 34 35 37 37 37 39 40 42 44 46 47 47 47 49 49 49 49 50 50 52 52 53 53 53 54 54 54 54 55 55 55 55 56 56 56 56 57 57 P1: GIG GRBT055-FM AISC-Sample (LRFD) xii June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Flange Local Buckling of Tees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Leg Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rectangular Bars and Rounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unsymmetrical Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Lateral-Torsional Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proportions of Beams and Girders . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Hole Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Proportioning Limits for I-Shaped Members . . . . . . . . . . . . . . . . . . . 3. Cover Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Built-Up Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 57 57 58 58 59 60 60 60 61 61 61 61 61 61 62 62 63 G. DESIGN OF MEMBERS FOR SHEAR . . . . . . . . . . . . . . . . . . . . . . . . G1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G2. Members with Unstiffened or Stiffened Webs . . . . . . . . . . . . . . . . . . 1. Nominal Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Transverse Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G3. Tension Field Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Limits on the Use of Tension Field Action . . . . . . . . . . . . . . . . . . . . . 2. Nominal Shear Strength with Tension Field Action . . . . . . . . . . . . . 3. Transverse Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G4. Single Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G5. Rectangular HSS and Box Members . . . . . . . . . . . . . . . . . . . . . . . . G6. Round HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G7. Weak Axis Shear in Singly and Doubly Symmetric Shapes . . . . . . . . . G8. Beams and Girders with Web Openings . . . . . . . . . . . . . . . . . . . . . . 64 64 64 64 66 66 66 67 67 68 68 68 68 69 F10. F11. F12. F13. H. DESIGN OF MEMBERS FOR COMBINED FORCES AND TORSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H1. Doubly and Singly Symmetric Members Subject to Flexure and Axial Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Doubly and Singly Symmetric Members in Flexure and Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Doubly and Singly Symmetric Members in Flexure and Tension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Doubly Symmetric Members in Single Axis Flexure and Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H2. Unsymmetric and Other Members Subject to Flexure and Axial Force . . . Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 70 70 70 71 72 73 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS H3. Members Under Torsion and Combined Torsion, Flexure, Shear and/or Axial Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Torsional Strength of Round and Rectangular HSS . . . . . . . . . . . . . . 2. HSS Subject to Combined Torsion, Shear, Flexure and Axial Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Strength of Non-HSS Members under Torsion and Combined Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I. DESIGN OF COMPOSITE MEMBERS . . . . . . . . . . . . . . . . . . . . . . . . I1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Nominal Strength of Composite Sections . . . . . . . . . . . . . . . . . . . . . . 1a. Plastic Stress Distribution Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1b. Strain-Compatibility Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Material Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Shear Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I2. Axial Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Encased Composite Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1b. Compressive Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1c. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1d. Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1e. Load Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1f. Detailing Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1g. Strength of Stud Shear Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Filled Composite Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Compressive Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2c. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2d. Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2e. Load Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2f. Detailing Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I3. Flexural Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. Effective Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1b. Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1c. Strength During Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Strength of Composite Beams with Shear Connectors . . . . . . . . . . . 2a. Positive Flexural Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Negative Flexural Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2c. Strength of Composite Beams with Formed Steel Deck . . . . . . . . . . 2d. Shear Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Flexural Strength of Concrete-Encased and Filled Members . . . . . . I4. Combined Axial Force and Flexure . . . . . . . . . . . . . . . . . . . . . . . . . I5. Special Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. xiii 74 74 75 76 77 77 77 77 78 78 78 78 79 79 79 80 80 80 81 81 81 81 82 82 82 82 83 83 83 83 83 83 83 83 84 84 85 88 89 89 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 xiv TABLE OF CONTENTS J. DESIGN OF CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Design Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Simple Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Compression Members with Bearing Joints . . . . . . . . . . . . . . . . . . . . 5. Splices in Heavy Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Beam Copes and Weld Access Holes . . . . . . . . . . . . . . . . . . . . . . . . . 7. Placement of Welds and Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. Bolts in Combination with Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. High-Strength Bolts in Combination with Rivets . . . . . . . . . . . . . . . . 10. Limitations on Bolted and Welded Connections . . . . . . . . . . . . . . . . J2. Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Groove Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. Effective Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1b. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Fillet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Effective Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Plug and Slot Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3a. Effective Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3b. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Combination of Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Filler Metal Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Mixed Weld Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J3. Bolts and Threaded Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. High-Strength Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Size and Use of Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Minimum Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Minimum Edge Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Maximum Spacing and Edge Distance . . . . . . . . . . . . . . . . . . . . . . . . 6. Tension and Shear Strength of Bolts and Threaded Parts . . . . . . . . . 7. Combined Tension and Shear in Bearing-Type Connections . . . . . . 8. High-Strength Bolts in Slip-Critical Connections . . . . . . . . . . . . . . . 9. Combined Tension and Shear in Slip-Critical Connections . . . . . . . 10. Bearing Strength at Bolt Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Special Fasteners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12. Tension Fasteners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J4. Affected Elements of Members and Connecting Elements . . . . . . . . . 1. Strength of Elements in Tension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Strength of Elements in Shear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Block Shear Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Strength of Elements in Compression . . . . . . . . . . . . . . . . . . . . . . . . . Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 90 90 90 90 91 91 91 92 92 92 93 93 93 93 93 95 95 95 95 97 97 97 98 101 102 102 102 102 105 106 106 106 108 109 109 110 111 111 111 111 112 112 112 113 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS J5. J6. J7. J8. J9. J10. xv Fillers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Column Bases and Bearing on Concrete . . . . . . . . . . . . . . . . . . . . . . Anchor Rods and Embedments . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flanges and Webs with Concentrated Forces . . . . . . . . . . . . . . . . . . 1. Flange Local Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Web Local Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Web Crippling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Web Sidesway Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Web Compression Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Web Panel Zone Shear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Unframed Ends of Beams and Girders . . . . . . . . . . . . . . . . . . . . . . . . 8. Additional Stiffener Requirements for Concentrated Forces . . . . . . 9. Additional Doubler Plate Requirements for Concentrated Forces . . 113 114 114 114 115 115 116 116 117 117 119 119 120 120 121 K. DESIGN OF HSS AND BOX MEMBER CONNECTIONS . . . . . . . . . . K1. Concentrated Forces on HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Definitions of Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Limits of Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Concentrated Force Distributed Transversely . . . . . . . . . . . . . . . . . . . 3a. Criterion for Round HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3b. Criteria for Rectangular HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Concentrated Force Distributed Longitudinally at the Center of the HSS Diameter or Width, and Acting Perpendicular to the HSS Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4a. Criterion for Round HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4b. Criterion for Rectangular HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Concentrated Force Distributed Longitudinally at the Center of the HSS Width, and Acting Parallel to the HSS Axis . . . . . . . . . . 6. Concentrated Axial Force on the End of a Rectangular HSS with a Cap Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . K2. HSS-to-HSS Truss Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Definitions of Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Criteria for Round HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Limits of Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Branches with Axial Loads in T-, Y- and Cross-Connections . . . . . . 2c. Branches with Axial Loads in K-Connections . . . . . . . . . . . . . . . . . . 3. Criteria for Rectangular HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3a. Limits of Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3b. Branches with Axial Loads in T-, Y- and Cross-Connections . . . . . . 3c. Branches with Axial Loads in Gapped K-Connections . . . . . . . . . . . 3d. Branches with Axial Loads in Overlapped K-Connections . . . . . . . . 3e. Welds to Branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 122 122 122 123 123 123 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 124 125 125 125 125 126 127 128 128 129 129 130 131 132 133 134 135 P1: GIG GRBT055-FM AISC-Sample (LRFD) xvi June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS K3. HSS-to-HSS Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . 1. Definitions of Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Criteria for Round HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Limits of Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Branches with In-Plane Bending Moments in T-, Y- and Cross-Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2c. Branches with Out-of-Plane Bending Moments in T-, Y- and Cross-Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2d. Branches with Combined Bending Moment and Axial Force in T-, Y- and Cross-Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Criteria for Rectangular HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3a. Limits of Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3b. Branches with In-Plane Bending Moments in T- and Cross-Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3c. Branches with Out-of-Plane Bending Moments in T- and Cross-Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3d. Branches with Combined Bending Moment and Axial Force in T- and Cross-Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 136 136 137 L. DESIGN FOR SERVICEABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . L1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L2. Camber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L3. Deflections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L4. Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L5. Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L6. Wind-Induced Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L7. Expansion and Contraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L8. Connection Slip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 143 143 144 144 144 144 144 144 M. FABRICATION, ERECTION AND QUALITY CONTROL . . . . . . . . . . M1. Shop and Erection Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M2. Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Cambering, Curving and Straightening . . . . . . . . . . . . . . . . . . . . . . . . 2. Thermal Cutting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Planing of Edges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Welded Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Bolted Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Compression Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Dimensional Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. Finish of Column Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. Holes for Anchor Rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. Drain Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Requirements for Galvanized Members . . . . . . . . . . . . . . . . . . . . . . . M3. Shop Painting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 145 145 145 145 146 146 146 147 147 147 147 147 148 148 148 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 137 138 138 139 140 140 141 142 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS xvii 2. Inaccessible Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Contact Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Finished Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Surfaces Adjacent to Field Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . M4. Erection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Alignment of Column Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Fit of Column Compression Joints and Base Plates . . . . . . . . . . . . . . 5. Field Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Field Painting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Field Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M5. Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Cooperation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Rejections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Inspection of Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Inspection of Slip-Critical High-Strength Bolted Connections . . . . 5. Identification of Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 148 148 148 148 148 148 149 149 149 149 149 149 150 150 150 150 150 APPENDIX 1. INELASTIC ANALYSIS AND DESIGN . . . . . . . . . . . . . . 1.1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3. Moment Redistribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4. Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5. Stability and Second-Order Effects . . . . . . . . . . . . . . . . . . . . . . . . . 1. Braced Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Moment Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6. Columns and Other Compression Members . . . . . . . . . . . . . . . . . . . 1.7. Beams and Other Flexural Members . . . . . . . . . . . . . . . . . . . . . . . . 1.8. Members under Combined Forces . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 151 151 151 152 153 153 153 153 154 154 154 APPENDIX 2. DESIGN FOR PONDING . . . . . . . . . . . . . . . . . . . . . . . . . 155 2.1. Simplified Design for Ponding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 2.2. Improved Design for Ponding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 APPENDIX 3. DESIGN FOR FATIGUE . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Calculation of Maximum Stresses and Stress Ranges . . . . . . . . . . . . . 3.3. Design Stress Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Bolts and Threaded Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5. Special Fabrication and Erection Requirements . . . . . . . . . . . . . . . . . 159 159 160 160 162 163 APPENDIX 4. STRUCTURAL DESIGN FOR FIRE CONDITIONS . . . . . 178 4.1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 4.1.1. Performance Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. P1: GIG GRBT055-FM AISC-Sample (LRFD) xviii June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS 4.1.2. Design by Engineering Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.3. Design by Qualification Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.4. Load Combinations and Required Strength . . . . . . . . . . . . . . . . . 4.2. Structural Design for Fire Conditions by Analysis . . . . . . . . . . . . . . . 4.2.1. Design-Basis Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.1. Localized Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.2. Post-Flashover Compartment Fires . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.3. Exterior Fires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.4. Fire Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.5. Active Fire Protection Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2. Temperatures in Structural Systems under Fire Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.3. Material Strengths at Elevated Temperatures . . . . . . . . . . . . . . . . 4.2.3.1. Thermal Elongation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.3.2. Mechanical Properties at Elevated Temperatures . . . . . . . . . . . . 4.2.4. Structural Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.1. General Structural Integrity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.2. Strength Requirements and Deformation Limits . . . . . . . . . . . . . 4.2.4.3. Methods of Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.3a. Advanced Methods of Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.3b. Simple Methods of Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.4. Design Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3. Design by Qualification Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.1. Qualification Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.2. Restrained Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.3. Unrestrained Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 180 180 180 180 181 181 181 181 181 APPENDIX 5. EVALUATION OF EXISTING STRUCTURES . . . . . . . . . 5.1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2. Material Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Determination of Required Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Tensile Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Chemical Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Base Metal Notch Toughness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Weld Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Bolts and Rivets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3. Evaluation by Structural Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Dimensional Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Strength Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Serviceability Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4. Evaluation by Load Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Determination of Load Rating by Testing . . . . . . . . . . . . . . . . . . . . . . 2. Serviceability Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5. Evaluation Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 187 187 187 187 188 188 188 188 188 188 189 189 189 189 190 190 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 181 182 182 182 183 183 183 184 184 184 185 185 185 185 186 P1: GIG GRBT055-FM AISC-Sample (LRFD) June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS xix APPENDIX 6. STABILITY BRACING FOR COLUMNS AND BEAMS . . 6.1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Relative Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Nodal Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Lateral Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. Relative Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1b. Nodal Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Torsional Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Nodal Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Continuous Torsional Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 191 191 192 192 193 193 193 193 194 194 195 APPENDIX 7. DIRECT ANALYSIS METHOD . . . . . . . . . . . . . . . . . . . . 7.1. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2. Notional Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3. Design-Analysis Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 196 196 196 COMMENTARY INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COMMENTARY GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. GENERAL PROVISIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A2. Referenced Specifications, Codes and Standards . . . . . . . . . . . . . . . . A3. Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Structural Steel Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. ASTM Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1c. Rolled Heavy Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Steel Castings and Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Bolts, Washers and Nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Anchor Rods and Threaded Rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Filler Metal and Flux for Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . A4. Structural Design Drawings and Specifications . . . . . . . . . . . . . . . . . 199 200 203 203 204 204 204 204 207 208 208 208 208 209 B. DESIGN REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B2. Loads and Load Combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . B3. Design Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Required Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Limit States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Design for Strength Using Load and Resistance Factor Design (LRFD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Design for Strength Using Allowable Strength Design (ASD) . . . . . 5. Design for Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Design of Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Design for Serviceability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. 210 210 211 213 213 213 214 216 217 218 222 P1: GIG GRBT055-FM AISC-Sample (LRFD) xx June 20, 2005 12:16 Char Count= 0 TABLE OF CONTENTS 8. Design for Ponding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. Design for Fatigue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. Design for Fire Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Design for Corrosion Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12. Design Wall Thickness for HSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B4. Classification of Sections for Local Buckling . . . . . . . . . . . . . . . . . . B5. Fabrication, Erection and Quality Control . . . . . . . . . . . . . . . . . . . . B6. Evaluation of Existing Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 222 222 222 222 223 223 226 226 C. STABILITY ANALYSIS AND DESIGN . . . . . . . . . . . . . . . . . . . . . . . . C1. Stability Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Member Stability Design Requirements . . . . . . . . . . . . . . . . . . . . . . . 3. System Stability Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3a. Braced-Frame and Shear-Wall Systems . . . . . . . . . . . . . . . . . . . . . . . 3b. Moment-Frame Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3c. Gravity Framing Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3d. Combined Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C2. Calculation of Required Strengths . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Methods of Second-Order Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 1a. General Second-Order Elastic Analysis . . . . . . . . . . . . . . . . . . . . . . . 1b. Second-Order Analysis by Amplified First-Order Elastic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2a. Design by Second-Order Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2b. Design by First-Order Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 227 227 228 229 229 229 229 229 230 230 231 D. DESIGN OF MEMBERS FOR TENSION . . . . . . . . . . . . . . . . . . . . . . D1. Slenderness Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D2. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D3. Area Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Gross Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Net Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Effective Net Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D4. Built-Up Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D5. Pin-Connected Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Dimensional Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D6. Eyebars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Tensile Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Dimensional Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 249 249 250 250 250 250 252 253 254 254 254 255 255 232 236 237 238 E. DESIGN OF MEMBERS FOR COMPRESSION . . . . . . . . . . . . . . . . . 256 E1. General Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256 E2. Slenderness Limitations and Effective Length . . . . . . . . . . . . . . . . . . 258 Specification for Structural Steel Buildings, March 9, 2005 AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC.