Normalized Hysteretic Energy Demand of SDOF System Subjected to Earthquake Excitation

Currently, the methods of energy-based seismic design have been widely developed. As cumulative response, hysteretic energy can be regarded as an index directly to estimate the earthquake induced structural damage, so it is important for researchers to analyze hysteretic energy demand of SDOF systems. For obtaining the mean demand of hysteretic energy, hysteretic energy is normalized as the ratio of hysteretic energy to square of peak ground acceleration, on the basis of which the spectra of normalized hysteretic energy of constant ductility factors is established. The earthquake motion records of three kinds of soil sites are selected as excitations of the SDOF system to analyze the regularities of mean demands of normalized hysteretic energy. The influence factors of hysteretic energy demand such as period, ductility factor and soil site are analyzed. Analytic results show that the spectra have the typical spectral pattern features for different soil sites, and the normalized hysteretic energy demand is affected obviously by ductility factor and soil site.