Inelastic acceleration ratio of structures under pulse-like earthquake ground motions

Abstract

The Inelastic Acceleration Ratio (IAR) is a useful index for the direct computation of the maximum inelastic acceleration from the corresponding elastic one. This parameter can be used for evaluating nonlinear response of structures, as well as acceleration-sensitive non-structural components. In this paper, constant strength spectra based on IAR are proposed under pulse-like earthquake ground motions. Moreover, the effects of structural parameters, including elastic vibration period normalized by the pulse period, the strength modification factor, viscous damping ratio and the hysteretic rule are examined on this index. The results reveal that the impacts of these parameters are significant for low values of the normalized period, when T/Tp < 1, and ξ = 0.05. Furthermore, analytical equations are introduced to estimate IAR as a function of the normalized elastic vibration period and the main structural characteristics, which can be used for the seismic evaluation of the acceleration-sensitive structures and of the non-structural components.