Disaster Prevention Research Institute, Kyoto University
Abstract
The objective of this paper is to clarify the aseismic safety of the ultimate state of space structures. A method of stochastic earthquake response analysis is presented, which extends the formulation of Y.K. Wen et al. by introducing a yielding condition and its associated flow rule into the differential equations of hysteresis rule. In order to study the effect of bi-directional ground motion on the responses such as ductility, hysteretic energy dissipation of space structures, the parametric analysis of various frequency ratios and strength ratios between perpendicular axes of structures is performed. The responses under bi-directional ground motion are compared with those under uni-directional motion and the effect of deterioration of hysteresis are also studied. As the results of the analysis, the following interesting conclusions were obtained: 1) Standard deviation of ductility response is affected by the frequency characteristics of space structure, especially in the smaller frequency direction, along which smaller ductility response is likely under uni-directional ground motion, 2) The effect of deterioration of hysteresis is remarkable in both axes of structure, especially in the case of bi-directional ground motion, 3) The effect of bi-directional ground motion is greater on the ductility response in the stronger axis of structure than in the weak axis, and when considering the deterioration of hysteresis, displacement responses in both directions increase but the total hysteretic energy dissipation under bi-directional motions is equal or less than that under uni-directional motion
