Effects of the Predominant Pulse on the Inelastic Displacement Ratios of Pulse-Like Ground Motions Based on Wavelet Analysis

Having a predominant pulse is the main feature for pulse-like ground motions differing from others. To investigate the influence of the predominant pulse on the inelastic displacement ratios of pulse-like ground motions, the wavelet analysis method is used to extract the predominant pulse. The results indicate that the inelastic displacement ratios of the pulse-removed parts obtained by subtracting the extracted pulse from the original pulse-like ground motions are close to the results of non-pulse-like ground motions. The ratio of the energy of the extracted pulse to the energy of the original ground motion is used to represent the pulse intensity. The results indicate that the pulse period determines the locations in which the inelastic displacement ratios would have noticeable increments, and the pulse intensity determines the degree of the increments. Besides, the effects of five commonly used parameters (PGV, PGD, PGV/PGA, Arias intensity Ia, and soil condition) on the inelastic displacement ratios of pulse-like ground motions and their relations to the pulse period and the pulse intensity are studied. Finally, a new model, in which the influence of pulse intensity is considered, to predict the inelastic displacement ratios of pulse-like ground motions is proposed.

Prestressed concrete wall system with friction devices: Seismic performance and direct displacement–based seismic design

It is convenient to use the inelastic displacement ratio spectra and residual displacement ratio spectra to predict the maximum inelastic displacement and residual displacement of building structures based on linear elastic analysis directly. The prestressed concrete wall system with friction devices (PCW-FD system) can be simulated by single-degree-of-freedom (SDOF) model with self-centering behavior. To investigate the seismic performance of PCW-FD system, the SDOF models with fully and non-fully self-centering behavior are analyzed firstly, and it is concluded that the hysteresis parameters (strength reduction coefficient, post-yield stiffness coefficient, energy dissipation coefficient, and period) have significant influence on the seismic responses (such as constant relative strength inelastic displacement ratio, constant relative strength residual displacement ratio, maximum absolute acceleration, the hysteretic energy, and site classifications) during short period, and the trends of the seismic responses are similar at different site classifications. Then a large amount of the result data is summarized, and the constant relative strength inelastic displacement ratio spectra and the constant relative strength residual displacement ratio spectra with enough precision (the correlation coefficients are 0.957 and 0.947, respectively) are established by conducting regression analysis. Finally, the direct displacement–based seismic design method is improved and verified to be suitable for PCW-FD system.

Inelastic response spectra of self-centering structures with the flag-shaped hysteretic response subjected to near-fault pulse-type ground motions

Many studies on the inelastic response spectra have mainly focused on structures with the conventional hysteretic behavior. However, for self-centering structures with the flag-shaped (FS) hysteretic behavior, the corresponding study is limited. The primary aim of this study is to investigate the inelastic response spectra of self-centering structures with FS hysteretic behavior subjected to the near-fault pulse-type ground motion. To this end, the smooth FS hysteretic model based on Bouc–Wen model is developed, and the characteristics of pulse-type ground motions are described in detail. It is found that the general features of inelastic response spectra of the FS model are sensitive to the acceleration-, velocity-, and displacement-sensitive spectral regions of the ground motion. The inelastic displacement, velocity, acceleration, and ductility factor spectra of the FS hysteretic model for pulse-type ground motions are much larger than those for ordinary ground motions, while the residual displacement spectra under the two types of ground motions are both very small due to its self-centering capacity. Moreover, the inelastic response spectra are affected by the ground motion characteristics and structural hysteresis behavior, especially the large pulse period and peak ground velocity (PGV) significantly increase the inelastic displacement, velocity, and acceleration spectra.