Estimation of Ultimate Safety for Soil-structure Interaction System and its Application to Aseismic Design

点击翻译按钮获取中文摘要

We have proposed several analytical and experimental methods and theories in this project to develop earthquake resistant design which combines the elastic and ductile design methods of soil-structure interaction system. The following four topics has been investigated :(1) Evaluation of dynamic soil-structure interactionA computer program has been developed to analyze foundation structure systems by substructure method and FEM. We analyzed dynamic nonlinear behaviour of three dimensional soil-structure interaction system taking into account sliding and separation between soil and and structures as well as material nonlinearity.(2) Analysis of failure process of foundation structuresDynamic stability of granular structures and foundation structures were studied by use of experimental and analytical methods. A new experimental technique to visualize dynamic behaviour of particles interlocking in a model was developed. The efficiency of this technique was examined by Distinct Element Method (DEM). DEM was applied to the dynamic problem of bearing capacity of piles.(3) Experimental study of underground structures and foundation structuresNonlinear dynamic earth pressure acting horizontally on side walls of an underground conduit was investigated by the experiments and numerical simulation. A hybrid study has been done to measure and identify nonlinear restoring force characteristics of pile foundations. A simple analytical method to simulate the behavior of soil-pile systems has been developed.(4) Development of simplified model for soil-structure systemFor the purpose of a simple aseismic design of civil structure, the coupling system of soil-structure interaction was replaced to the simple sway-rocking (S-R) model. Simple estimation method of the vibration characteristics for the ground was developed by use of the spectrum ratio of microtremors.