EFFECT OF PARTICLE ORBIT CHARACTERISTICS ON ELASTIC-PLASTIC SEISMIC RESPONSE OF STRUCTURAL MODELS

Abstract

 In this paper, the difference of orbit characteristics of bi-directional input waves affecting the elastic-plastic response of structural models is investigated. The proposed method extends conventional 1D spectrum-compatible method to 2D, and shows how to match the random trajectory time histories, which is orthogonal in the horizontal plane, with the target bi-axial response spectrum. By extending the energy spectrum which represents the energy of input seismic motion, the concept of bi-axial energy spectrum is proposed. Using this spectrum, differences in input seismic energy is shown when acceleration trajectories of the waves vary. In addition, incremental dynamic analysis (IDA) was carried out for elasto-plastic structural model, causing excitation by bi-axial response spectrum-compatible accelerograms with different acceleration trajectories. As a result, there is tendency for using circular trajectory as seismic input to show conservative result of elasto-plastic seismic response analysis.