True Nonlinear Seismic Response Analyses of Soil Deposits

By the increase of strong motion data, special attention is brought to the nonlinear dynamics response analysis of soil layers. The computations are presented by using finite difference formulations. The formulations are adopted to a MATLAB program which permits the response computations in absolute or relative parameters. The program reliability is verified with the result of NERA software. Viscoelastic, elastoplastic constitutive relations are introduced and hyperbolic models are mentioned here, nonlinearity is treated by selecting strain compatible soil properties such as shear stiffness and viscous coefficient. Stepwise material properties are taken as the instantaneous slope and assumed to be constant within the given time interval. The software has been used to predict the seismic response at hypothesized site sites (Joyner, W, 1975). The maximum input acceleration was scaled from 0.1 g to 1 g and the soil parameters were known from the sites. The comparison results have shown that the response is matching.