Ground-motion models for inelastic response spectra using NGA-West2 database

This article presents ground-motion models (GMMs) for inelastic response spectra using the NGA-West2 database. The inelastic response spectra are defined in terms of constant ductility. The GMMs are used to observe the effect of event scenarios, site conditions, and oscillator properties on maximum displacement. Using a large database enabled us to quantify the magnitude scaling of inelastic response as compared to that for the traditional elastic GMMs. We observe that using the magnitude scaling of elastic GMM for hazard analysis of inelastic structural response can be unconservative for large magnitudes and large ductility ratios. To compare our models with models in the literature, we use the developed GMMs to compute the Reduction Factor due to inelasticity. Comparison of this model with models in the literature shows the importance of considering the effect of magnitude on the Reduction Factor. We also observe that the ratio of RotD100/RotD50 is larger for inelastic single-degree-of-freedom system than that for elastic system, and the ratio increases with increasing ductility.