NONLINEAR MULTIMODAL PUSHOVER ANALYSIS METHOD FORSPATIAL STRUCTURES

摘要

An improved nonlinear multimodal pushover analysis method is presented to incorporate contributions ofrnmultiple modes and the effects of their interactions to the responses. The key step for the method is to obtainrnequivalent static seismic force for the important vibration modes. An existing method for building structuresrnbased on SRSS combination of the nonlinear modal responses is first extended to spatial structures. A newrnmethod is next presented to combine the modal loads before conducting pushover analysis. The proposedrnmethod is general and independent of the types of the structures, and does not rely on the properties for buildingrnstructures. The proposed method is applied to a long span arch structure to show that the nonlinear multimodalrnpushover method is capable of estimating the seismic response of spatial structures with moderately goodrnaccuracy.