Three-Dimensional Static and Dynamic Analysis of Structures
kVy"+ ZebK A Physical Approach With Emphasis on Earthquake Engineering
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$4ka +nfU Edward L. Wilson
O2/%mFS. Professor Emeritus of Structural Engineering
Pxap;;\ University of California at Berkeley
<<i=+ed8eP :p,c%" 8 Copyright Computers and Structures, Inc., 1996-2001
>qr=l,Hi The CSI Logo is a trademark of Computers and Structures, Inc.
!d/`[9jY SAP90, SAP2000, SAFE, FLOOR and ETABS are trademarks of
F>p%2II/ Computers and Structures, Inc.
<Wp`[S]r ISBN 0-923907-00-9
qdKh6{ 9Y; }JVS Preface To Third Edition
7&#'c8]/qh This edition of the book contains corrections and additions to the July 1998 edition.
y>?k< )nA{ Most of the new material that has been added is in response to questions and comments
Ty)gPh6O from the users of SAP2000, ETABS and SAFE.
\XZU'JIO Chapter 22 has been written on the direct use of absolute earthquake displacement
mI2|0RWI)l loading acting at the base of the structure. Several new types of numerical errors for
*{HGLl|= absolute displacement loading have been identified. First, the fundamental nature of
SB5@ \^ displacement loading is significantly different from the base acceleration loading
*4zoAs lU1 traditionally used in earthquake engineering. Second, a smaller integration time step is
rHH#@ Zx required to define the earthquake displacement and to solve the dynamic equilibrium
>:="?'N5l! equations. Third, a large number of modes are required for absolute displacement
9
Wxq) loading to obtain the same accuracy as produced when base acceleration is used as the
g]:..W 7 loading. Fourth, the 90 percent mass participation rule, intended to assure accuracy of
ytg7p 5{!i the analysis, does not apply for absolute displacement loading. Finally, the effective
D-;J;m
\ modal damping for displacement loading is larger than when acceleration loading is
.0 rJIO used.
AviT+^7E To reduce those errors associated with displacement loading, a higher order integration
bDxPgb7N= method based on a cubic variation of loads within a time step is introduced in Chapter
77)OW $G 13. In addition, static and dynamic participation factors have been defined that allow the
N)`tI0/W structural engineer to minimize the errors associated with displacement type loading. In
9t,aT!f addition, Chapter 19 on viscous damping has been expanded to illustrate the physical
x*3@,GmZl effects of modal damping on the results of a dynamic analysis.
"#[o?_GaJ Appendix H, on the speed of modern personal computers, has been updated. It is now
Z?vY3) possible to purchase a personal computer for approximately $1,500 that is 25 times
\xy:6gd : faster than a $10,000,000 CRAY computer produced in 1974.
lv*Wnn@k Several other additions and modifications have been made in this printing. Please send
:h3#1fko your comments and questions to
ed@csiberkeley.com.
}Ox2olUX Edward L. Wilson
!$g(& April 2000
