NONLINEAR ANALYSIS OF SEISMIC GROUND RESPONSE

Abstract

Long structures like bridges, pipelines, tunnels eta, experience different response at 'the same time instant. For dynamic analysis of any structure by finite element method, ground motion is required at the boundary points. Some structures like dam, bridge, nuclear power plant and under ground power plant are critical from an overall viewpoint and/or the provision of relief services after earthquakes. Thus it Is very important to determine as precise as possible the spatial/temporal distribution of the seismic ground response. The work described herein may be divided into two major parts : the. determination of spatial/temporal distribution of seismic ground response; and the parametric studies. For 'the first part, a computer software was developed for linear as well as nonlinear analysis, using principles of wave propagation. Effect of inclined propagation of seismic wave and for nonlinear analysis, dynamic properties of the soil as a function of time was -taken into account. In case of absence of experimental data, a stress--strain relationship has also been proposed. For the presentation of capability of software the effect of magnitude and period of input sinusoidal excitation (at base layer level) on a particular five layer system has been studied. And amplification factor obtained by wave propagation method has been compared with IS; Code recommendation.