类旗帜型滞回模型体系的近断层等损伤位移谱

NEAR-FAULT CONSTANT-DAMAGE DISPLACEMENT SPECTRA OF GENERALIZED FLAG-SHAPED HYSTERESIS MODEL

面向于近断层区域自复位体系的抗震设计需求,为了揭示自复位体系的弹塑性行为,基于Park-Ang双参数损伤模型建立了类旗帜型滞回模型的等损伤位移谱,研究损伤指标模型参数和滞回模型参数对位移谱的影响,分别对比分析了等损伤与等延性位移谱以及近断层脉冲型与无脉冲地震动作用下等损伤位移谱的差异,通过回归分析建立等损伤位移谱预测方程。研究表明:采用脉冲周期进行周期标准化能够反映脉冲效应在短周期段内对位移谱的局部放大作用,同时能降低中长周期段内位移谱的离散性;极限延性系数对短周期段内位移谱值的影响超过20%;等损伤及等延性位移谱的对比分析说明,累积滞回耗能对自复位体系位移需求的影响不能忽视;与无脉冲地震动位移谱值相比,近断层脉冲型地震动位移谱值在标准化周期约为0.5和1.0时增大20%左右。构建的等损伤位移谱预测模型可用于近断层区域自复位体系位移响应的预测。

To meet the seismic design requirements of a self-centering system in near fault area, and to reveal the elastoplastic performance of structures under seismic excitations, the C;(constant-damage displacement spectra)of a self-centering system was established based on the Park-Ang damage model. The results were statistically organized to evaluate the influence of damage model parameters and hysteretic model parameters on C;. The differences of an inelastic displacement spectra based on constant-damage approach and constant-ductility approach, and the differences of C;corresponding to near-fault pulse-like and non-pulse-like ground motions were compared and analyzed. A prediction equation was proposed to estimate C;of the self-centering system.Results show that: the period normalization with respect to pulse period can reflect the local amplification effect of the pulse characteristic on the values of C;in the short period range, and effectively reduce the dispersion of C;. The influence of ultimate ductility coefficient on the values of C;is more than 20% in the short period range. The comparative analysis of C;and Cμ(constant-ductility displacement spectra) shows that the effect of cumulative hysteretic energy dissipation on displacement demand of self-centering systems cannot be ignored. In comparison with no-pulse-like ground motions, near-fault pulse-like ground motions can significantly increase the values of C;at the normalized period around 0.5 and 1.0, and magnitude of increase can reach about 20%. The proposed prediction equation can be applied to anticipating the displacement response of self-centering systems in near fault area.