PARAMETRIC STUDIES OF SEISMIC GROUND RESPONSE USING NONLINEAR ANALYSIS

Abstract

One part of the dynamic analysis is determination of spatial/temporal distribution of seismic ground response along the boundaries chosen for the system that include the structure and the surrounding medium. Seismic ground motion records indicate that spatial variations in ground motions can be significant, especially when the structure has a considerable length. Some structure like dam, bridge, nuclear power plant and under ground structures are critical from an overall viewpoint and 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 program was developed for linear as well as nonlinear analysis, using principles of wave propagation. Effect of inclined propagation of seismic wave and for the 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.