|
|
|
|
|
Peak earthquake response of structures under multi-component excitationsJianwei Song, Zach
Liang, Yi-Lun Chu and George C. Lee
Abstract: Accurate estimation of the peak seismic
responses of structures is important in earthquake resistant design. The
internal force distributions and the seismic responses of structures are quite
complex, since ground motions are multi-directional. One key issue is the
uncertainty of the incident angle between the directions of ground motion and
the reference axes of the structure. Different assumed seismic incidences can
result in different peak values within the scope of design spectrum analysis for
a given structure and earthquake ground motion record combination. Using time
history analysis to determine the maximum structural responses excited by a
given earthquake record requires repetitive calculations to determine the
critical incident angle. This paper presents a transformation approach for
relatively accurate and rapid determination of the maximum peak responses of a
linear structure subjected to three-dimensional excitations within all possible
seismic incident angles. The responses can be deformations, internal forces,
strains and so on. An irregular building structure model is established using
SAP2000 program. Several typical earthquake records and an artificial white
noise are applied to the structure model to illustrate the variation of the
maximum structural responses for different incident angles. Numerical results
show that for many structural parameters, the variation can be greater than
100%. This method can be directly applied to time history analysis of structures
using existing computer software to determine the peak responses without
carrying out the analyses for all possible incident angles. It can also be used
to verify and/or modify aseismic designs by using response spectrum analysis.
|
|
