Effects of Surface Motion Difference at Footings on the Earthquake Responses of Large-Span Gable Structures

Abstract

In this paper the spatial distributions of earthquake motions on shallow alluvial valleys with an irregularity in soil layer composition are first checked. Based on the results of analysis, the seismic responses of a large-span gable structure are calculated considering the input difference at the footings due to spatial distributions of the motions. The results of calculation show that the different acceleration inputs will excite an additional vibration associated especially with the second natural symmetric mode as well as the first natural anti-symmetric mode. Furthermore, a method for calculating the seismic responses to the structures is proposed to consider the different inputs based on the results of present paper.