Behavior factors for nonlinear structures subjected to multiple near-fault earthquakes

A new procedure for the ductility demands control of single-degree-of freedom systems under repeated near-fault earthquakes is proposed. This objective is achieved using appropriate behavior factors. Using software developed in-house, elastic and inelastic spectra are computed for various viscous damping ratios, post-yield stiffness ratios and ductility levels. In order to achieve a unique, simple and effective empirical expression for the behavior factors, a comprehensive nonlinear regression analysis of 26,124,000 dynamic inelastic analyses is applied. Examining the influence of seismic sequences, it is concluded that frequent/smaller near-fault earthquakes necessitate equal or smaller behavior factors in comparison with the ‘design earthquake’.