Near-fault directivity pulse-like ground motion effect on high-speed railway bridge
Near-fault directivity pulse-like ground motion effect on high-speed railway bridge
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DOI：
10.1007/s11771-014-2196-9
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发表时间：
2014-06-01
影响因子：
4.4
通讯作者：
Guo Wei
中科院分区：
文献类型：
--
作者：
Chen Ling-kun;Zhang Nan;Guo Wei
采用车辆-轨道-桥梁（VTB）单元研究了高速铁路桥在近断层指向性脉冲地面运动作用下的反应。基于PEER NAG强地震动数据库，建立了车桥系统的空间分析模型，推导了模拟列车与桥梁相互作用的VTB单元，计算了桥梁的弹塑性地震响应。计算结果表明，与远场地震相比，近断层定向性脉状地震动作用下，梁、墩顶位移和桥墩基础弯矩增大，近断层震动作用下的变形响应越大，荷载反转周期越少。近断层指向性脉动地震作用下桥墩的滞回特性应明确表示为桥墩基础弯矩-转动关系，其特征是在荷载时程曲线的某一点上出现集中强化的滞回循环。结果表明，由于高垂直地震动，梁跨中存在竖向挠度的放大。因此，在桥梁抗震设计中，应利用垂直地震动的影响来调整垂直-水平峰值地震动比的2/3的非保守放大常数。
The vehicle-track-bridge (VTB) element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions. Based on the PEER NAG Strong Ground Motion Database, the spatial analysis model of a vehicle-bridge system was developed, the VTB element was derived to simulate the interaction of train and bridge, and the elasto-plastic seismic responses of the bridge were calculated. The calculation results show that girder and pier top displacement, and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes, and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading. The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base, which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve. The results show that there is an amplification of the vertical deflection in the girder's mid-span owing to the high vertical ground motion. In light of these findings, the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.