ABSTRACT

To investigate the correlations of duration indexes and the nonlinear seismic responses of long-span continuous rigid-frame bridges with high-rise piers (CRFB-LH), an irregular CRFB-LH was selected as the prototype bridge. A construction stage analysis model was simulated in MIDAS/Civil, where the actual construction process was considered and the internal force state was extracted. After that, a nonlinear dynamic analysis model of the CRFB-LH with the equivalent internal force state was simulated via OpenSees. A bracketed duration and significant duration with a continuous-time interval were selected as the duration indexes. Sixty ground motion records with total duration values ranging from 9.91 s to 300 s were used in the nonlinear dynamic analysis. The correlation between the two duration indexes and the nonlinear seismic responses of the CRFB-LH under total-duration ground motions were analyzed. Finally, the effect of different duration indexes on the nonlinear seismic responses of the CRFB-LH was discussed under 30 long-duration ground motions intercepted according to D_b0.1g, D_s5-75% and D_s5-95%. The numerical results show that the correlations of D_s with nonlinear seismic responses are better than those of D_b, and the latter heavily depends on the absolute acceleration threshold. D_s5-95% is preferred for calculating the total hysteretic energy dissipated (HED) from the CRFB-LH. Additionally, while the amount of total HED is not determined by the total duration, the effective time interval of the ground motion duration under different duration indexes has a significant influence on the total HED.

摘要

为研究大跨度高墩连续刚构桥（CRFB-LH）的持续时间指标与非线性地震响应的相关性，选择不规则CRFB-LH作为原型桥。在 MIDAS/Civil 中模拟了施工阶段分析模型，其中考虑了实际施工过程并提取了内力状态。之后，通过OpenSees模拟了具有等效内力状态的CRFB-LH的非线性动力学分析模型。选择括号持续时间和具有连续时间间隔的显着持续时间作为持续时间指标。非线性动力分析中使用了 60 个总持续时间值范围为 9.91 秒至 300 秒的地震动记录。分析了两种历时指标与CRFB-LH在全历时地震动作用下的非线性地震响应的相关性。最后，讨论了不同持续时间指标对CRFB-LH非线性地震响应的影响，在30个长持续时间地震动截获下，根据D _{b0.1 g}、D _s5-75%和D _s5-95%。数值结果表明，D _s与非线性地震响应的相关性优于D _b，后者在很大程度上取决于绝对加速度阈值。D _s5-95%优选用于计算 CRFB-LH 的总滞后能量耗散 (HED)。此外，虽然总 HED 的量不取决于总持续时间，但不同持续时间指标下地震动持续时间的有效时间间隔对总 HED 有显着影响。