Influence of ground-motion duration on constant ductility response spectra considering various hysteretic models

Currently, there is extensive research on the influence of duration on structures, but most of these studies focus on specific structures or components. The conclusions of different scholars are not uniform, particularly in quantitatively assessing the influence of duration on structures. To address this issue, the duration effect from the perspective of response spectra was discussed in this study. Firstly, we matched 100 pairs of long- and short-duration ground motions, then input them into three SDOF systems of the modified Clough, strength and stiffness-degrading, and pinching-degrading models to calculate damage measures including acceleration, displacement, input energy, hysteretic energy, and damage index. Constant ductility response spectra and their spectral ratios containing these five damage measures are generated, and the differences in the spectra and spectral ratios of long- and short-duration ground motions are analyzed. Lastly, we also discussed the correlation between duration and the damage measures of various hysteretic models. The results show that duration has almost no effect on the acceleration and displacement, but the input energy, hysteresis energy, and damage index under long-duration motions can be as high as 1.5 to 3.0 times those of short-duration motions, especially for short-period structures where the duration effect is more significant than for long-period ones. Additionally, the duration effect varies across structures with different constitutive models. The findings of this study can provide references for future seismic design methods that consider the influence of duration.