Transverse failure modes and control strategies of super long-span cable-stayed bridge under extreme earthquake
Transverse failure modes and control strategies of super long-span cable-stayed bridge under extreme earthquake
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DOI：
10.21595/jve.2017.18267
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发表时间：
2017-12
影响因子：
1
通讯作者：
Wen Xie;Limin Sun
中科院分区：
文献类型：
--
作者：
Wen Xie;Limin Sun
本文对一座试验设计的超大跨度斜拉桥的破坏模式和控制策略进行了研究。主跨1400m的超高塔在不同地震烈度下的破坏模式，探讨了超高塔破坏模式的主要特征。然后，几种控制策略，如使用传统的粘性流体阻尼器(缩写。提出了一种新的组合策略，即牺牲弹塑性杆件与常规变幅杆相结合的组合策略，以改善网壳结构在极端地震(PGA=1.0g)下的破坏模式，减轻结构的震害。研究发现，超高塔在地震作用下经历了一种双塑性铰的意外破坏模式，在横向破坏上呈现出不同于中小跨度斜拉桥的新特点。而桥墩则表现出典型的、预期的弯曲破坏模式，横向上只有一个塑性铰。采用最优VFDs的常规控制策略虽然可以显著降低结构的地震损伤，但不能完全满足结构的抗震控制要求。在满足抗震控制目标的情况下，新的组合控制策略能够有效地改善结构的破坏模式和震害，其效果优于传统的基于最优变结构控制的组合控制策略。
This work is focused on the failure modes and control strategies of a trial designed super long-span cable-stayed bridge (Abbr. CSB) with a main span of 1400 m under various seismic intensities, exploring the key characteristic of the failure modes of super high tower. Then several control strategies, such as the use of conventional viscous fluid dampers (Abbr. VFDs) and a new combination strategy comprising sacrificial inelastic links and conventional VFDs, are presented for the failure modes improvement and the seismic damage mitigation of the CSB under extreme earthquake (PGA = 1.0 g). It is found that the super high tower experiences an unexpected failure mode with double plastic hinges that shows a new characteristic on the tower failure in the transverse direction, which is different from that of the short- and medium-span cable-stayed bridge during earthquake excitation. Whereas the piers show a typical and expected flexural failure mode with only one plastic hinge in the transverse direction. Although conventional control strategies using the optimal VFDs can help to significantly reduce the seismic damage of the CSB, they cannot entirely make the tower satisfy seismic control targets. It is also observed that the new combination strategy can successfully improve the failure mode and seismic damage of the CSB that satisfies seismic control targets, the effects of proposed combination strategy on the CSB are superior to those of the convention control strategy with the optimal VFDs.