When reinforced concrete structures are subjected to earthquake ground motion, the structural system is likely to develop some damage. Many researchers had proposed damage index for the purpose of quantifying the damage potential developed during seismic event. In general the damage potential could be determined by the combination of maximum deformation response and the hysteretic energy dissipation. In this study, an equivalent linearization method to estimate the maximum deformation of single-degree-of-freedom system is used to develop the ductility demand and damage spectra. The result from nonlinear dynamic analysis with total 348 ground motion records is used to investigate the uncertainty of the approximation method under various site conditions. Since equivalent linearization method is relatively easy to use, the development of the ductility demand spectra can be used as a tool by the engineers in specifying the design strength or ductility capacity level. Additionally, cumulative effect of cyclic loading and the aftershock effect are also discussed in this study.

When reinforced concrete structures are subjected to earthquake ground motion, the structural system is likely to develop some damage. Many researchers had proposed damage index for the purpose of quantifying the damage potential developed during seismic event. In general the damage potential could be determined by the combination of maximum deformation response and the hysteretic energy dissipation. In this study, an equivalent linearization method to estimate the maximum deformation of single-degree-of-freedom system is used to develop the ductility demand and damage spectra. The result from nonlinear dynamic analysis with total 348 ground motion records is used to investigate the uncertainty of the approximation method under various site conditions. Since equivalent linearization method is relatively easy to use, the development of the ductility demand spectra can be used as a tool by the engineers in specifying the design strength or ductility capacity level. Additionally, cumulative effect of cyclic loading and the aftershock effect are also discussed in this study.

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