Peak floor acceleration demand prediction based on response spectrum analysis of various sophistication

Abstract

This paper addresses the prediction of the median peak floor total acceleration (PFA) demand in spatial elastic structures subjected to seismic excitation. The prediction is based on various response spectrum methods of different degrees of sophistication. Beginning with a recently presented complete-quadratic-combination (CQC) rule for PFA demands, several approximations and simplifications concerning the correlation between modal contributions, peak factors, and cross-spectral moments are discussed, leading to the proposed modified modal combination rules. On several earthquake-excited multi-story spatial generic frame structures, the accuracy of the considered rules is assessed. The outcomes of response history analysis serves as benchmark solution. The results show that the modified CQC rules are simple in practical application and lead to reliable estimations of the median PFA demand of spatial structures with negligible loss of accuracy if peak factors are considered.