Asian Journal of Applied Sciences1996-3343xxxx-xxxxKnowledgia Review10.3923/ajaps.2009.348.362AlsulayfaniB.J.SaaedT.E.4200924The aim of this study is to determines the effects of
methods of analysis used in the analysis and design of high rise steel
buildings. As it known, many methods are available for the structural
analysis of buildings and other civil engineering structures under seismic
actions. The differences between them lie in the way they incorporate
the seismic input and in the idealization of the structure. There are
two procedures for specifying seismic design forces: first, the equivalent
static force and second, the dynamic analysis which can take a number
of forms. Mode superposition is one of these forms. Design codes have
proposed different formulas to obtain a more reasonable estimate of the
maximum response from the spectral values (SRSS, CQC, ASCE-98, TEN, ABS,
CSM). This research studies the effect of these formulas in the analysis
and design of high rise reentrant steel buildings. The study then compares
the resulting steel sections weight using static and dynamic analysis,
the latter being by means of mode combination methods to show the difference
between these formulas, to determine the most influenced structural members
and to obtain the vertical loads factor in order to get the required sections
using common static analysis for preliminary design purposes. The study
shows that modal combination methods slightly affect the result of design
for building; the difference among the formulas does not exceed more than
2.5%. The columns especially those at lower floors are mainly affected
by seismic forces, while the beams are slightly affected. Finally, a factor
of (10.5%) of the total vertical loads (excluding self weight of the building)
can be used to predict the members sections, instead of dynamic analysis
which is time consuming even with high speed computers like those used
in this research.]]>Naiem, F.,1989Edward, L.W.,2002Ray, W.C. and J. Penzien, 2003