Inelastic displacement ratio for high damping SDOF systems built on soft soil sites

The main purpose of this study is to estimate the inelastic displacement ratio, C1, of highly damped systems built on soft soil sites. For this purpose, results of linear and nonlinear time history analysis of 79 single-degree-of-freedom (SDOF) systems with damping ratios of 0.05, 0.1, 0.2, 0.3 and post-yield stiffness ratios of -0.01, 0, 0.05 and 0.1 under a large number of ground motion records obtained at soft soil deposits, were used. Oscillators exhibited ductility levels as high as 6. Based on the results, a new simplified equation as a function of the period of vibration normalized by the predominant period of ground motion records, the level of inelastic deformation, post-yield stiffness ratio and damping ratio for structures built on soft soil, has been proposed using nonlinear regression analysis.