Cold-Formed Steel Design E-Book

Wei-Wen Yu

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1121

Veröffentlichungsjahr: 2010

Beschreibung

The definitive text in the field, thoroughly updated andexpanded Hailed by professionals around the world as the definitive texton the subject, Cold-Formed Steel Design is an indispensableresource for all who design for and work with cold-formed steel. Noother book provides such exhaustive coverage of both the theory andpractice of cold-formed steel construction. Updated and expanded toreflect all the important developments that have occurred in thefield over the past decade, this Fourth Edition of the classic textprovides you with more of the detailed, up-to-the-minute technicalinformation and expert guidance you need to make optimum use ofthis incredibly versatile material for building construction. Wei-Wen Yu and Roger LaBoube, respected authorities in thefield, draw upon decades of experience in cold-formed steel design,research, teaching, and development of design specifications toprovide guidance on all practical aspects of cold-formed steeldesign for manufacturing, civil engineering, and buildingapplications. Throughout the book, they describe the structuralbehavior of cold-formed steel members and connections from both thetheoretical and experimental perspectives, and discuss therationale behind the AISI and North American design provisions.Cold-Formed Steel Design, Fourth Edition features: * Thoroughly up-to-date 2007 North American (AISI S100) designspecifications * Both ASD and LRFD methods for USA and Mexico * LSD (Limit States Design) method for Canada * A new chapter on the Direct Strength Method * Updates and revisions of all 14 existing chapters * In-depth design examples and explanation of designprovisions Cold-Formed Steel Design, Fourth Edition is a necessarytool-of-the-trade for structural engineers, manufacturers,construction managers, and architects. It is also an excellentadvanced text for college students and researchers in structuralengineering, architectural engineering, construction engineering,and related disciplines.

Leseprobe

Table of Contents

Title Page

Copyright Page

PREFACE

CHAPTER 1 - Introduction

1.1 GENERAL REMARKS

1.2 TYPES OF COLD-FORMED STEEL SECTIONS AND THEIR APPLICATIONS

1.3 STANDARDIZED METAL BUILDINGS AND INDUSTRIALIZED HOUSING

1.4 METHODS OF FORMING

1.5 RESEARCH AND DESIGN SPECIFICATIONS

1.6 GENERAL DESIGN CONSIDERATIONS OF COLD-FORMED STEEL CONSTRUCTION

1.7 ECONOMIC DESIGN AND OPTIMUM PROPERTIES

CHAPTER 2 - Materials Used in Cold-Formed Steel Construction

2.1 GENERAL REMARKS

2.2 YIELD STRESS, TENSILE STRENGTH, AND STRESS-STRAIN CURVE

2.3 MODULUS OF ELASTICITY, TANGENT MODULUS, AND SHEAR MODULUS

2.4 DUCTILITY

2.5 WELDABILITY

2.6 FATIGUE STRENGTH AND TOUGHNESS

2.7 INFLUENCE OF COLD WORK ON MECHANICAL PROPERTIES OF STEEL

2.8 UTILIZATION OF COLD WORK OF FORMING

2.9 EFFECT OF TEMPERATURE ON MECHANICAL PROPERTIES OF STEEL

2.10 TESTING OF FULL SECTIONS AND FLAT ELEMENTS

2.11 RESIDUAL STRESSES DUE TO COLD FORMING

2.12 EFFECT OF STRAIN RATE ON MECHANICAL PROPERTIES

CHAPTER 3 - Strength of Thin Elements and Design Criteria

3.1 GENERAL REMARKS

3.2 DEFINITIONS OF TERMS

3.3 DESIGN BASIS

3.4 SERVICEABILITY

3.5 STRUCTURAL BEHAVIOR OF COMPRESSION ELEMENTS AND DESIGN CRITERIA

3.6 PERFORATED ELEMENTS AND MEMBERS

3.7 PLATE BUCKLING OF STRUCTURAL SHAPES

3.8 ADDITIONAL INFORMATION

CHAPTER 4 - Flexural Members

4.1 GENERAL REMARKS

4.2 BENDING STRENGTH AND DEFLECTION

4.3 DESIGN OF BEAM WEBS

4.4 BRACING REQUIREMENTS OF BEAMS

4.5 TORSIONAL ANALYSIS OF BEAMS AND COMBINED BENDING AND TORSIONAL LOADING

4.6 ADDITIONAL INFORMATION ON BEAMS

CHAPTER 5 - Compression Members

5.1 GENERAL REMARKS

5.2 YIELDING

5.3 FLEXURAL COLUMN BUCKLING

5.4 TORSIONAL BUCKLING AND FLEXURAL-TORSIONAL BUCKLING

5.5 EFFECT OF LOCAL BUCKLING ON COLUMN STRENGTH

5.6 DISTORTIONAL BUCKLING STRENGTH OF COMPRESSION MEMBERS

5.7 EFFECT OF COLD WORK ON COLUMN BUCKLING

5.8 NORTH AMERICAN DESIGN FORMULAS FOR CONCENTRICALLY LOADED COMPRESSION MEMBERS

5.9 EFFECTIVE LENGTH FACTOR K

5.10 BUILT-UP COMPRESSION MEMBERS

5.11 BRACING OF AXIALLY LOADED COMPRESSION MEMBERS

5.12 DESIGN EXAMPLES

5.13 COMPRESSION MEMBERS HAVING ONE FLANGE FASTENED TO DECKS OR PANELS

5.15 ADDITIONAL INFORMATION ON COMPRESSION MEMBERS

CHAPTER 6 - Combined Axial Load and Bending

6.1 GENERAL REMARKS

6.2 COMBINED TENSILE AXIAL LOAD AND BENDING

6.3 COMBINED COMPRESSIVE AXIAL LOAD AND BENDING (BEAM-COLUMNS)

6.4 NORTH AMERICAN DESIGN CRITERIA

6.5 DESIGN EXAMPLES

6.6 SECOND-ORDER ANALYSIS

6.7 ADDITIONAL INFORMATION ON BEAM-COLUMNS

CHAPTER 7 - Closed Cylindrical Tubular Members

7.1 GENERAL REMARKS

7.2 TYPES OF CLOSED CYLINDRICAL TUBES

7.3 FLEXURAL COLUMN BUCKLING

7.4 LOCAL BUCKLING

7.5 NORTH AMERICAN DESIGN CRITERIA

7.6 DESIGN EXAMPLES

CHAPTER 8 - Connections

8.1 GENERAL REMARKS

8.2 TYPES OF CONNECTORS

8.3 WELDED CONNECTIONS

8.4 BOLTED CONNECTIONS

8.5 SCREW CONNECTIONS

8.6 OTHER FASTENERS

8.7 RUPTURE FAILURE OF CONNECTIONS

8.8 I-OR BOX-SHAPED COMPRESSION MEMBERS MADE BY CONNECTING TWO C-SECTIONS

8.9 I-BEAMS MADE BY CONNECTING TWO C-SECTIONS

8.10 SPACING OF CONNECTIONS IN COMPRESSION ELEMENTS

CHAPTER 9 - Shear Diaphragms and Roof Structures

9.1 GENERAL REMARKS

9.2 STEEL SHEAR DIAPHRAGMS

9.3 STRUCTURAL MEMBERS BRACED BY DIAPHRAGMS

9.4 SHELL ROOF STRUCTURES

9.5 METAL ROOF SYSTEMS

CHAPTER 10 - Corrugated Sheets

10.1 GENERAL REMARKS

10.2 APPLICATIONS

10.3 SECTIONAL PROPERTIES AND DESIGN OF ARC- AND TANGENT- TYPE CORRUGATED SHEETS

10.4 SECTIONAL PROPERTIES AND DESIGN OF TRAPEZOIDAL-TYPE CORRUGATED SHEETS

CHAPTER 11 - Composite Design

11.1 GENERAL REMARKS

11.2 STEEL-DECK-REINFORCED COMPOSITE SLABS

11.3 COMPOSITE BEAMS OR GIRDERS WITH COLD-FORMED STEEL DECK

CHAPTER 12 - Introduction to Stainless Steel Design

12.1 GENERAL REMARKS

12.2 DIFFERENCES BETWEEN SPECIFICATIONS FOR CARBON STEELS AND STAINLESS STEELS

CHAPTER 13 - Light-Frame Construction

13.1 GENERAL REMARKS

13.2 FRAMING STANDARDS

13.3 DESIGN GUIDES

CHAPTER 14 - Computer-Aided Design

14.1 GENERAL REMARKS

14.2 COMPUTER PROGRAMS FOR DESIGN OF COLD-FORMED STEEL STRUCTURES

CHAPTER 15 - Direct-Strength Method

15.1 GENERAL REMARKS

15.2 NORTH AMERICAN DSM PROVISIONS

15.3 COMMENTARY ON APPENDIX 1 (DSM)

15.4 DIRECT-STRENGTH METHOD DESIGN GUIDE

15.5 DESIGN EXAMPLES

APPENDIX A - Thickness of Base Metal

APPENDIX B - Torsion

APPENDIX C - Formulas for Computing Cross-Sectional Property β

APPENDIX D - Definitions of Terms

Nomenclature

Acronyms and Abbreviations

Conversion Table

REFERENCES

INDEX

This book is printed on acid-free paper.

Copyright © 2010 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Yu, Wei-wen, 1924-

Cold-formed steel design / Wei-Wen Yu, Roger A. LaBoube. - 4th ed.

p. cm.

Includes bibliographical references and index.

ISBN 978-0-470-46245-4 (cloth); ISBN 978-0-47074-3 (ebk); ISBN 978-0-47075-0 (ebk); ISBN 978-0-47076-7 (ebk)

1. Building, Iron and steel. 2. Sheet-steel. 3. Thin-walled structures. 4. Steel-Cold working. I. LaBoube, Roger A. II. Title.

TA684.Y787 2010

624.1’821-dc22

2010005153

PREFACE

This fourth edition of the book has been prepared to provide readers with a better understanding of the analysis and design of the thin-walled, cold-formed steel structures that have been so widely used in building construction and other areas in recent years. It is a revised version of the first author’s book, Cold-Formed Steel Design, third edition, published by John Wiley & Sons, Inc. in 2000. All the revisions are based on the 2007 edition of the North American Specification with Supplement No.1, which combines the allowable strength design (ASD), the load and resistance factor design (LRFD), and the limit states design (LSD) methods.

The material was originally developed for graduate courses and short courses in the analysis and design of cold-formed steel structures and is based on experience in design, research, and development of the American Iron and Steel Institute (AISI) and North American design criteria.

Throughout the book, descriptions of the structural behavior of cold-formed steel members and connections are given from both theoretical and experimental points of view. The reasons and justification for the various design provisions of the North American specification are discussed at length. Consequently the text not only will be instructive for students but also can serve as a major source of reference for structural engineers and researchers.

Of the published book’s 15 chapters, Chapters 1-9 and 13 have been completely revised according to the combined ASD/LRFD/LSD North American specification and framing standards. Other chapters have been updated on the basis of available information. Chapter 15 is a new chapter on the direct-strength method.

Chapter 1 includes a general discussion of the application of cold-formed steel structures and a review of previous and recent research. It also discusses the development of design specifications and the major differences between the design of cold-formed and hot-rolled steel structural members. Because of the many research projects in the field that have been conducted worldwide during the past 35 years, numerous papers have been presented at various conferences and published in a number of conference proceedings and engineering journals. At the same time, new design criteria have been developed in various countries. These new developments are reviewed in this chapter.

Since material properties play an important role in the performance of structural members, the types of steels and their most important mechanical properties are described in Chapter 2. In addition to the revision of Table 2.1, new information on the use of low-ductility steel for concentrically loaded compression members has been included in Section 2.4. Section 2.6 includes additional information on fatigue strength.

In Chapter 3, the strength of thin elements and design criteria are discussed to acquaint the reader with the fundamentals of local buckling and postbuckling strength of thin plates and with the basic concepts used in design. This chapter has been completely revised to include detailed information on design bases for ASD, LRFD, and LSD with a revised Table 3.1, the unstiffened elements with stress gradient, the uniformly compressed elements with intermediate stiffeners, and noncircular holes.

Chapter 4 deals with the design of flexural members. Because the design provisions were revised extensively during 2001-2007, this chapter has been completely rewritten to cover the design of beams using ASD, LRFD, and LSD methods. It includes new and revised design information on inelastic reserve capacity of beams with unstiffened elements, distortional buckling strength, shear strength of webs, web crippling strength and combination with bending, bearing stiffeners in C-section beams, bracing requirements, and beams having one flange fastened to a standing seam roof system.

The design procedures for compression members are discussed in Chapter 5. This chapter has been brought up to date by including new design information on distortional buckling strength, built-up members, bracing requirements, and Z-section members having one flange fastened to a standing seam roof.

In 2007, the North American specification introduced the second-order analysis approach as an optional method for stability analysis. A new Section 6.6 has been added in Chapter 6 to deal with this alternative method. In addition, revisions have also been made on the design of beam-columns using ASD, LRFD, and LSD methods.

Chapter 7 covers the design of closed cylindrical tubes. This revised chapter reflects the rearrangement of design provisions in the North American specification and minor changes made in the 2007 edition of the specification.

Like the member design, the design of connections has been updated in Chapter 8 using the ASD, LRFD, and LSD methods with additional and revised design provisions for bearing strength between bolts and connected parts, combined shear and tension in bolts, block shear strength, revised design information on screw connections, and power-actuated fasteners.

Because various types of structural systems, such as shear diaphragms and shell roof structures, have become increasingly popular in building construction, Chapter 9 contains design information on these types of structural systems. It includes the new standard for the cantilever test method for shear diaphragms and the revised design procedure for wall studs. A new Section 9.5 has been added for metal roof systems.

The sectional properties of standard corrugated sheets are discussed in Chapter 10 because they have long been used in buildings for roofing, siding, and other applications. Minor revisions have been made in Section 10.4.

Steel decks are widely used in building construction. Consequently the updated information in Chapter 11 on their use in steel-deck-reinforced composite slabs and composite beams is timely.

Chapter 12 contains an introduction to the design of cold-formed stainless steel structural members supplementing the information on cold-formed carbon steel structural members in other chapters. This chapter has been updated on the basis of the revised Structural Engineering Institute/American Society of Civil Engineers (SEI/ASCE) Standard 8-02 and recent research findings for the design of cold-formed stainless steel structural members.

During recent years, cold-formed steel members have been used increasingly for residential and commercial construction. The previous Chapter 14 has been completely rewritten based on new and revised framing standards. This chapter has been changed to Chapter 13 using the new title of Light-Frame Construction.

The increasing use of computers for design work warrants the brief introduction that is given in the revised Chapter 14 for the computer-aided design of cold-formed steel structures.

In 2004, a new Appendix 1 was added in the North American specification for the use of the direct-strength method to determine the nominal axial strength for columns and flexural strength for beams. These alternative design procedures are discussed in the new Chapter 15. Also discussed in this chapter are the Commentary on Appendix 1, the Direct Strength Method Design Guide, and design examples.

It is obvious that a book of this nature would not have been possible without the cooperation and assistance of many individuals, organizations, and institutions. It is based primarily on the results of continuing research programs on cold-formed steel structures that have been sponsored by the American Iron and Steel Institute (AISI), the ASCE, the Canadian Sheet Steel Building Institute (CSSBI), the Cold-Formed Steel Engineers Institute (CFSEI) of the Steel Framing Alliance (SFA), the Metal Building Manufacturers Association (MBMA), the Metal Construction Association (MCA), the National Science Foundation (NSF), the Rack Manufacturers Institute (RMI), the Steel Deck Institute (SDI), the Steel Stud Manufacturers Association (SSMA), and other organizations located in the United States and abroad. The publications related to cold-formed steel structures issued by AISI and other institutions have been very helpful for the preparation of this book.

The first author is especially indebted to his teacher, the late Professor George Winter of Cornell University, who made contributions of pronounced significance to the building profession in his outstanding research on cold-formed steel structures and in the development of AISI design criteria. A considerable amount of material used in this book is based on Dr. Winter’s publications.

Our sincere thanks go to Mr. Robert J. Wills, Vice President, Construction Market Development, Steel Market Development Institute (a business unit of the American Iron and Steel Institute), for permission to quote freely from the North American Specification, Commentary, Design Manual, Framing Standards, Design Guides, and other AISI publications. An expression of appreciation is also due to the many organizations and individuals that granted permission for the reproduction of quotations, graphs, tables, and photographs. Credits for the use of such materials are given in the text.

We wish to express our sincere thanks to Mr. Don Allen, Mr. Roger L. Brockenbrough, Dr. Helen Chen, Mr. Jay W. Larson, Professor Teoman B. Pekoz, Professor Benjamin W. Schafer, Professor Reinhold M. Schuster and Professor Cheng Yu for their individual reviews of various parts of the manuscript. Their suggestions and encouragement have been of great value to the improvement of this book.

We are very grateful to Mrs. Christina Stratman for her kind assistance in the preparation of this book. Thanks are also due to Miss Domenica Cambio and Miss Mingyan Deng for their careful typing and preparation of drawings. The financial assistance provided by the Missouri University of Science and Technology through the first author’s Curators’ Professorship and the sponsors for the Wei-Wen Yu Center for Cold-Formed Steel Structures is appreciated.

This book could not have been completed without the help and encouragement of the authors’ wives, Yuh-Hsin Yu and Karen LaBoube, as well as for their patience, understanding, and assistance.

Wei-Wen Yu Roger A. LaBoube

Rolla, MissouriMarch 2010

CHAPTER 1

Introduction

1.1 GENERAL REMARKS

In steel construction, there are two main families of structural members. One is the familiar group of hot-rolled shapes and members built up of plates. The other, less familiar but of growing importance, is composed of sections cold formed from steel sheet, strip, plate, or flat bar in roll-forming machines or by press brake or bending brake operations.1.1,1.2,1.31 These are cold-formed steel structural members. The thickness of steel sheet or strip generally used in cold-formed steel structural members ranges from 0.0149 in. (0.378 mm) to about ¼ in. (6.35 mm). Steel plates and bars as thick as 1 in. (25.4 mm) can be cold formed successfully into structural shapes.1.1,1.4,1.314,1.336,1.345

Although cold-formed steel sections are used in car bodies, railway coaches, various types of equipment, storage racks, grain bins, highway products, transmission towers, transmission poles, drainage facilities, and bridge construction, the discussions included herein are primarily limited to applications in building construction. For structures other than buildings, allowances for dynamic effects, fatigue, and corrosion may be necessary.1.314,1.336,1.345

The use of cold-formed steel members in building construction began in about the 1850s in both the United States and Great Britain. However, such steel members were not widely used in buildings until around 1940. The early development of steel buildings has been reviewed by Winter.1.5-1.7

Since 1946 the use and the development of thin-walled cold-formed steel construction in the United States have been accelerated by the issuance of various editions of the “Specification for the Design of Cold-Formed Steel Structural Members” of the American Iron and Steel Institute (AISI).1.267,1.345 The earlier editions of the specification were based largely on the research sponsored by AISI at Cornell University under the direction of George Winter since 1939. It has been revised subsequently to reflect the technical developments and the results of continuing research.1.267,1.336,1.346

In general, cold-formed steel structural members provide the following advantages in building construction:

1. As compared with thicker hot-rolled shapes, cold-formed light members can be manufactured for relatively light loads and/or short spans.

2. Unusual sectional configurations can be produced economically by cold-forming operations (Fig. 1.1), and consequently favorable strength-to-weight ratios can be obtained.

3. Nestable sections can be produced, allowing for compact packaging and shipping.

4. Load-carrying panels and decks can provide useful surfaces for floor, roof, and wall construction, and in other cases they can also provide enclosed cells for electrical and other conduits.

5. Load-carrying panels and decks not only withstand loads normal to their surfaces, but they can also act as shear diaphragms to resist force in their own planes if they are adequately interconnected to each other and to supporting members.

Figure 1.1 Various shapes of cold-formed sections.11

Compared with other materials such as timber and concrete, the following qualities can be realized for cold-formed steel structural members1.8,1.9:

1. Lightness

2. High strength and stiffness

3. Ease of prefabrication and mass production

4. Fast and easy erection and installation

5. Substantial elimination of delays due to weather

6. More accurate detailing

7. Nonshrinking and noncreeping at ambient temperatures

8. Formwork unneeded

9. Termite proof and rot proof

10. Uniform quality

11. Economy in transportation and handling

12. Noncombustibility

13. Recyclable material

The combination of the above-mentioned advantages can result in cost saving in construction.

1.2 TYPES OF COLD-FORMED STEEL SECTIONS AND THEIR APPLICATIONS

Cold-formed steel structural members can be classified into two major types:

1. Individual structural framing members

2. Panels and decks

The design and the usage of each type of structural members have been reviewed and discussed in a number of publications.1.5-1.75,1.267-1.285,1.349,1.358

1.2.1 Individual Structural Framing Members

Figure 1.2 shows some of the cold-formed sections generally used in structural framing. The usual shapes are channels (C-sections), Z-sections, angles, hat sections, I-sections, T-sections, and tubular members. Previous studies have indicated that the sigma section (Fig. 1.2d ) possesses several advantages such as high load-carrying capacity, smaller blank size, less weight, and larger torsional rigidity as compared with standard channels.1.76

Figure 1.2 Cold-formed sections used in structural framing.1.6

Figure 1.3 Building composed entirely of cold-formed steel sections. (Courtesy of Penn Metal Company.)1.7

In general, the depth of cold-formed individual framing members ranges from 2 to 12 in. (50.8 to 305 mm), and the thickness of material ranges from 0.048 to about ¼ in. (1.22 to about 6.35 mm). In some cases, the depth 4 of individual members may be up to 18 in. (457 mm), and the thickness of the member may be ½ in. (12.7 mm) or thicker in transportation and building construction. Cold-formed steel plate sections in thicknesses of up to about ¾ or 1 in. 19.1 or 25.4 mm) have been used in steel plate structures, transmission poles, and highway sign support structures.

In view of the fact that the major function of this type of individual framing member is to carry load, structural strength and stiffness are the main considerations in design. Such sections can be used as primary framing members in buildings up to six stories in height. In 2000, the 165-unit Holiday Inn in Federal Way, Washington, utilized eight stories of axial load bearing cold-formed steel studs as the primary load-bearing system. shows a two-story building. In tall multistory buildings the main framing is typically of heavy hot-rolled shapes and the secondary elements may be of cold-formed steel members such as steel joists, studs, decks, or panels ( and ). In this case the heavy hot-rolled steel shapes and the cold-formed steel sections supplement each other.