Inelastic Deformation Ratio Evaluation and Application to the Seismic Codes

This paper present a new semi-analytical approach aims to estimating the inelastic deformation ratio for SDOF bilinear systems. The new proposed approach combines both the inelastic and elastic maximum lateral displacement demands instead of combining the yield-strength reduction factor and the ductility factor. The new inelastic deformation ratio on one hand depends on the inelastic properties of systems (the period, the post-to-preyield stiffness ratio, the yield strength coefficient, the normalized yield strength coefficient), on the other hand the elastic spectral response acceleration \((S_{a} )\) that is presented in seismic design codes, such as the Federal Emergency Management Agency FEMA and Eurocode8. The results are compared to those of the Nonlinear Time History Analysis (NL-THA) and some existing formulations for three different reinforced concrete (R.C.) 2D-frames subjected to the record ground motion of El-Centro 1940 (N/S).