Inelastic Displacement Ratio Spectrum for Near-Fault Ground Motions

Abstract—This paper examines the spectrum of inelastic displacement ratio (IDR) for structures subjected to near-fault earthquakes. IDR can be defined as the ratio of the maximum inelastic to the maximum elastic displacement of a structure and allows the computation of its maximum inelastic displacement directly from the corresponding elastic counterpart. Extensive parametric analyses are carried out to obtain empirical expressions for this ratio, in terms of the period of vibration and ductility demands.