A STUDY ON A GENERATION OF SIMULATED EARTHQUAKE GROUND MOTION CONSIDERING PHASE DIFFERENCE CHARACTERISTICS : Part 5 Generation method of the vertical earthquake ground motion on the basis of its correlation with the horizontal motion

Abstract

In this paper, a generation method of simulated vertical earthquake ground motion for the structural design of buildings is proposed. In the method, the observed data corresponded to the horizontal component, which is selected in generating the horizontal motion, is applied to the Fourier phase of the vertical motion. The Fourier amplitude of the vertical motion on the seismic bedrock is regarded as the same as the one prescribed for the horizontal one, since it is indicated that the SH and SV waves on the seismic bedrock have the similar Fourier amplitude averagely and this idea is verified by analyzing recorded earthquake motions. The vertical motion on the ground is synthesized with the Fourier phase and amplitude above-mentioned considering the soil amplification. It is, moreover, illustrated that the resemblance between the H/V spectrum and the transfer function of the soil can be explained by the similarity between the SH and SV waves' Fourier amplitude on the seismic bedrock.