An Efficient Calculation Method for Seismic Spectral Analysis under Multiple Support Excitations

The seismic spectral computation of structures is time-consuming under multiple-support excitations. The seismic spectral response of structures can be expressed based on several correlation coefficients and the time consumption can be greatly reduced if the coefficients are expressed in closed-form. In this paper, approximate expressions of spatial coherence functions are suggested. Then integrals for the coefficients are carried out analytically and their closed-form expressions are obtained. The closed-form expressions are developed from Clough-Penziens APSD and Hus APSD. The numerical results show that the approximate closed-form expressions of correlation coefficients are of enough engineering accuracy and high efficiency.