09-10-2014, 04:32 PM
Generally, for seismic analysis of multiply supported engineering structures
design earthquake loads are specified in terms of response spectra. In the
analysis of multiply supported structures subjected to multi component
excitations, engineers are faced with the problem of combining maximum
response quantities contributed from different excitations. The conventional
method of solving this problem is by assuming mutually independent excitations
which ignores the correlation effects between different excitations. In this work a
new combination rule is developed using the critical cross power spectral density
functions in which support excitations are modelled as stationary gaussian
random process. The cross correlation effects between different excitations are
brought in such a way that the response quantity of interest is maximised. This
method is derived using fundamental principles of random vibration theory. It
can estimate the maximum possible response of a structure under a set of
incompletely specified seismic loading conditions.