Three-Dimensional Static and Dynamic Analysis of Structures
Acr\2!)) A Physical Approach With Emphasis on Earthquake Engineering
#6'oor X K^t M$l\ by
+<6L>ZAL Edward L. Wilson
STu!v5XY}- Professor Emeritus of Structural Engineering
2D` @$)KL University of California at Berkeley
NylN-X7[# fI[tU(x Copyright Computers and Structures, Inc., 1996-2001
!zLd ,` The CSI Logo is a trademark of Computers and Structures, Inc.
CF9a~^ +% SAP90, SAP2000, SAFE, FLOOR and ETABS are trademarks of
1C+Y|p?KA Computers and Structures, Inc.
"L.)ML ISBN 0-923907-00-9
qC?J`
i`7{q~d= Preface To Third Edition
<.( IJ This edition of the book contains corrections and additions to the July 1998 edition.
t
),~w,7(J Most of the new material that has been added is in response to questions and comments
Cl[ '6L k from the users of SAP2000, ETABS and SAFE.
aKS
2p3 Chapter 22 has been written on the direct use of absolute earthquake displacement
O _0|Q@ loading acting at the base of the structure. Several new types of numerical errors for
Nkn0G _ absolute displacement loading have been identified. First, the fundamental nature of
a#FkoA~M displacement loading is significantly different from the base acceleration loading
r<V]MwO= traditionally used in earthquake engineering. Second, a smaller integration time step is
VaQ>g*(I required to define the earthquake displacement and to solve the dynamic equilibrium
:k8>)x]
) equations. Third, a large number of modes are required for absolute displacement
Rct|"k_"Ys loading to obtain the same accuracy as produced when base acceleration is used as the
.g DWv loading. Fourth, the 90 percent mass participation rule, intended to assure accuracy of
4][m!dsU the analysis, does not apply for absolute displacement loading. Finally, the effective
%1SA!1>j modal damping for displacement loading is larger than when acceleration loading is
!y$H r[v used.
r&)/3^S ' To reduce those errors associated with displacement loading, a higher order integration
rxC EOG method based on a cubic variation of loads within a time step is introduced in Chapter
53P\OG^G` 13. In addition, static and dynamic participation factors have been defined that allow the
C$ oY,A, structural engineer to minimize the errors associated with displacement type loading. In
} !\NdQs addition, Chapter 19 on viscous damping has been expanded to illustrate the physical
m9ts &b+TE effects of modal damping on the results of a dynamic analysis.
'|&}rLr:+ Appendix H, on the speed of modern personal computers, has been updated. It is now
{"!V&} possible to purchase a personal computer for approximately $1,500 that is 25 times
VJBV k8P faster than a $10,000,000 CRAY computer produced in 1974.
2G:)27Q- Several other additions and modifications have been made in this printing. Please send
>8Z z<S&z your comments and questions to
ed@csiberkeley.com.
z %{>d#rw Edward L. Wilson
pl
Ii April 2000
