An Empirical Equation to Predict the Mean Residual Displacement Ratios in Constant Ductility Sdof Systems Under Strong Motion Records In Iran

The evaluation of residual displacement of structures is a critical problem because it has important role in the Definition of post-earthquake performance level of structures. In this paper, the mean residual displacement ratios (RDRs) (residual displacement normalized by maximum inelastic displacement) are computed for constant ductility of single-degree-of-freedom (SDOF) systems subjected to 116 strong ground motion records from severe earthquakes events in Iran. A total number of 25,056 nonlinear response history analyses (RHAs) were performed to accurately evaluate RDRs. The influence of frequency content and significant duration of ground motions on mean RDRs are evaluated and discussed statistically. The results indicated that the validity of influence of these ground motion parameters on mean RDRs is dependently of the post yield stiffness ratio and the influence of these parameters becomes more obvious for SDOF systems with post-yield stiffness greater than zero. The obtaining data from RHAs results were used for the development of new mean RDRs equation. It has been found that the proposed equation can predict mean RDRs with adequate accuracy.