design of steel structures

403 Pages·2011·6.4 MB·English

DESIGN OF STEEL
STRUCTURES
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Copyright © 1995 Springer Science+Business Media Dordrecht
Original1y pub1ished by Chapman & Hall in 1995
Softcover reprint ofthe hardcover 1st edition 1995
All rights reserved. No part of this work covered by the copyright hereon may be reproduced
or used in any form or by any means-graphic, electronic, or mechanical, including
photocopying, recording, taping, or information storage and retrieval systems-without the
written permission of the publisher.
1 234567 8 9 10 XXX 01 009997 9695
Library of Congress Cataloging-in-Publication Data
Abu-Saba, Elias G.,
Design of steel structures / by Elias G. Abu-Saba.
p. cm.
Includes bibliographical references and index.
ISBN 978-1-4613-5864-0 ISBN 978-1-4615-2079-5 (eBook)
DOI 10.1007/978-1-4615-2079-5
1. Building, Iron and steel. 2. Structural design. 3. Load factor design. 1. Title.
TA684.A144 1995
693' .71-dc20 94-48546
CIP
I dedicate this book to the memory of my parents, Jurjis and Sabat
Abu-Saba, who did not have the privilege to go to school. Yet they
believed in the power of knowledge and provided us, their children, with
the opportunity to learn and grow.
The infinite spans the human mind.
The spirit spins free of space and time.
The joy and sadness of life are a wink
In the eternal flow.
The stream cascades and meanders
To merge and be lost in the greater sea.
ELIAS G. ABU-SABA
November 6. 1994
Contents
Preface xiii
1 Introduction 1
1.1 Introduction 1
1.2 Structural Steel and Its Properties in Construction 4
1.3 Applications 7
1.4 Loads, Load Factors, and Load Combinations 13
2 Tension Members 14
2.1 Introduction 14
2.2 Design Criteria 14
2.3 ASD Method 15
2.4 LRFD Method 17
2.5 Effective Area of Riveted and Bolted Tension Members 20
2.6 Effective Area for Staggered Holes of Tension Members 21
2.7 Tension Rods in Design of Purlins 27
2.8 Limitation of Length of Tension Members on Stiffness:
Slenderness Ratio 25
2.9 Applications 25
3 Compression Members 46
3.1 Introduction 46
3.2 Derivation of Euler's Formula 47
3.3 Design Criteria for Compression Members Under
oncentric Load: ASD Method 49
3.4 Effective Length and Slenderness Ratio 51
3.5 Design Criteria for Compression Members
Under Concentric Load: LRFD Method 54
ix
x Contents
3.6 SI LRFD Design Criteria (Axial Compression) 60
3.7 Compression Members in Braced Frames: ASD Method 63
3.8 Axial Compression and Bending: ASD Method 64
3.9 Reduction in Live Loads 65
3.10 Columns Subject to Bending and Axial Force in a
Braced System: LRFD Method
3.11 Design of Columns for Braced and Unbraced Frames:
ASDMethod 82
4 Designs of Bending Members 106
4.1 Introduction 106
4.2 Simple Bending 106
4.3 Design of Beams and Other Flexural Members:
ASD Allowable Bending Stress 109
4.4 Deflections and Vibrations of Beams in Bending 116
4.5 Design for Flexure: LRFD Method 124
4.6 Use of the Load Factor Design Selection Table Zx
for Shapes Used as Beams 1128
4.7 Serviceability Design Considerations and the
LRFDMethod 132
5 Torsion and Bending 133
5.1 Introduction 133
5.2 Torsional Stresses 133
5.3 Plane Bending Stresses 137
5.4 Combining Torsional and Bending Stresses 137
5.5 Torsional End Conditions 138
5.6 Torsional Loading and End Conditions 139
5.7 Applications 144
6 Design of Bracings for Wind and Earthquake Forces 150
6.1 Introduction 150
6.2 Wind Forces 150
6.3 Wind Velocity Pressure 151
6.4 Selection of Basic Wind Speed (mph) 155
Contents xi
6.5 External Pressures and Combined External and
Internal Pressures 155
6.6 Wind Pressure Profile Against Buildings 165
6.7 Analysis of Braced Frames for Wind Forces 166
6.8 Introduction to Seismic Design 175
6.9 Equivalent Static Force Procedure 177
7 Connections 187
7.1 Introduction 187
7.2 Types of Connections 187
7.3 Framed Beam Connection: Bolted 190
7.4 Framed Beam Connection: Welded E70XX Electrodes for
Combination with Table II and Table III Connections 196
8 Anchor Bolts and Baseplates 201
8.1 Introduction 201
8.2 Design of Column Baseplates 201
9 Built-Up Beams: Plate Girders 210
9.1 Introduction 210
9.2 Design of Plate Girders by ASD Method 210
9.3 Approximate Method for Selection of Trial Section 214
10 Composite Construction 246
10.1 Introduction 246
10.2 Design Conceptualization and Assumptions 246
10.3 Development of Section Properties 249
10.4 Short-Cut Method for Determining Sxbc 264
10.5 Shear Connectors 282
10.6 Bethlehem Steel Table for Selecting Shear Connectors 284
10.7 LRFD Method: Design Assumptions 285
10.8 LRFD Flexural Members 287
xii Contents
11 Plastic Analysis and Design of Structures 294
11.1 Introduction 294
11.2 Bending of Beams 294
11.3 Design of Beams: Failure Mechanism Approach 301
11.4 Fixed End Beam 308
11.5 Plastic Hinges: Mechanism of Failure 310
11.6 Fixed End Beam with Multiple Concentrated Loads 317
11.7 Continuous Beams 319
11.8 Portal Frames 329
11.9 Minimum Thickness (Width-Thickness Ratio) 332
11.10 Plastic Analysis of Gabled Frames 337
12 Influence of Axial Forces on Plastic Moment 340
12.1 Introduction 340
12.2 Influence of Axial Forces on Plastic Moment Capacity 340
13 Rigid Connections 350
13.1 Introduction 351
13.2 Straight Corner Connection 355
13.3 Stiffener for a Straight Corner Connection 357
13.4 Haunched Connections 364
13.5 Haunched Connections with Concentrated Loads 368
13.6 Design Guides: Connections 375
14 Multistory Buildings: Plastic Design 375
14.1 Introduction 376
14.2 Allowable Stress vs. Plastic Design Methods 376
14.3 Application to Multistory Buildings 379
Index 389
Preface
This book is intended for classroom teaching in architectural and civil
engineering at the graduate and undergraduate levels. Although it has
been developed from lecture notes given in structural steel design, it can
be useful to practicing engineers. Many of the examples presented in this
book are drawn from the field of design of structures.
Design of Steel Structures can be used for one or two semesters of three
hours each on the undergraduate level. For a two-semester curriculum,
Chapters 1 through 8 can be used during the first semester. Heavy
emphasis should be placed on Chapters 1 through 5, giving the student a
brief exposure to the consideration of wind and earthquakes in the design
of buildings. With the new federal requirements vis a vis wind and
earthquake hazards, it is beneficial to the student to have some under
standing of the underlying concepts in this field. In addition to the class
lectures, the instructor should require the student to submit a term project
that includes the complete structural design of a multi-story building using
standard design procedures as specified by AISC Specifications. Thus, the
use of the AISC Steel Construction Manual is a must in teaching this
course. In the second semester, Chapters 9 through 13 should be covered.
At the undergraduate level, Chapters 11 through 13 should be used on a
limited basis, leaving the student more time to concentrate on composite
construction and built-up girders.
Chapters 6, 11, 12, 13, and 14 can be used for a graduate course. As a
prerequisite for the graduate course, the student must have a minimum of
three credit hours in the design of steel structures. The instructor will go
into more depth in the presentation of Chapters 6, 11, 12, and 13. The
student should be required to submit a term project using rigid frames in
multi story buildings. Chapter 14 provides a simple method which can
easily be computerized, allowing the student the facility of designing
medium- to high-rise buildings using steel frames. U. S. customary units
are used throughout, although some examples are presented with S. I.
units. To help students convert from U. S. units to S. I. units, tables of
conversion are provided in Chapter 1.
The allowable stress design method (ASD) is used predominantly in this
book. To help the student appreciate the load and resistance factored
xiii