Three-Dimensional Static and Dynamic Analysis of Structures
M,b<B_$ A Physical Approach With Emphasis on Earthquake Engineering
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# by
t!6\7Vm/ Edward L. Wilson
gzl%5`DB w Professor Emeritus of Structural Engineering
GAg.p?Sq University of California at Berkeley
> [Xm|A# 2. StG(Y! Copyright Computers and Structures, Inc., 1996-2001
_Ct}%-,4 The CSI Logo is a trademark of Computers and Structures, Inc.
H "Q(2I SAP90, SAP2000, SAFE, FLOOR and ETABS are trademarks of
ggrI>vaw Computers and Structures, Inc.
xT{TVHdU ISBN 0-923907-00-9
'4af
], hVlyEsLg Preface To Third Edition
G[|3^O>P This edition of the book contains corrections and additions to the July 1998 edition.
!d:tIu{) Most of the new material that has been added is in response to questions and comments
I?f"<5[0 from the users of SAP2000, ETABS and SAFE.
TZ^{pvBy Chapter 22 has been written on the direct use of absolute earthquake displacement
kA1RfSS loading acting at the base of the structure. Several new types of numerical errors for
1k!D0f3qb absolute displacement loading have been identified. First, the fundamental nature of
hWe}' L- displacement loading is significantly different from the base acceleration loading
5T! &r traditionally used in earthquake engineering. Second, a smaller integration time step is
-6u H. required to define the earthquake displacement and to solve the dynamic equilibrium
3cmbK equations. Third, a large number of modes are required for absolute displacement
-0A@38, } loading to obtain the same accuracy as produced when base acceleration is used as the
Hm.X}HO0L loading. Fourth, the 90 percent mass participation rule, intended to assure accuracy of
LTg?5GwD\j the analysis, does not apply for absolute displacement loading. Finally, the effective
zSEr4^Dk4 modal damping for displacement loading is larger than when acceleration loading is
<2n'}&F used.
bZxv/\ To reduce those errors associated with displacement loading, a higher order integration
&(lMm ) method based on a cubic variation of loads within a time step is introduced in Chapter
5/Ydv
RB67 13. In addition, static and dynamic participation factors have been defined that allow the
9U!JK3d structural engineer to minimize the errors associated with displacement type loading. In
+ckMT3 addition, Chapter 19 on viscous damping has been expanded to illustrate the physical
qv.[ k<~a> effects of modal damping on the results of a dynamic analysis.
{&u Rd?( Appendix H, on the speed of modern personal computers, has been updated. It is now
Z$Z`@&U= possible to purchase a personal computer for approximately $1,500 that is 25 times
g;$E1U=R-E faster than a $10,000,000 CRAY computer produced in 1974.
cYsR 0# Several other additions and modifications have been made in this printing. Please send
8&i;hZm your comments and questions to
ed@csiberkeley.com.
G"}qV%"6" Edward L. Wilson
DG_}9M!DW@ April 2000
