波浪-地震联合作用下跨海斜拉桥横向减振控制研究∗

Lateral Vibration Control of Offshore Cable-stayed Bridge under Combined Earthquake and Wave Loads

摘要:

为研究波浪?地震联合作用下跨海斜拉桥的横向减振控制方法，以某主跨 400 m 的跨海斜拉桥为工程背景，考虑桥梁下部结构高桩承台群桩基础的波浪荷载，并基于辐射波浪理论求解地震动水力附加质量，建立了波浪-地震联合作用下考虑水?结构相互作用的全桥有限元模型。在此基础上，采用黏滞阻尼器构建横向减振体系，分别探讨了波浪单独作用和波浪?地震联合作用下黏滞阻尼器的减振控制效果。结果表明：在波浪单独作用下，仅在辅助墩墩顶设置黏滞阻尼器的横向阻尼体系减振效果较好，能有效抑制波浪荷载引起的主梁横向位移；在波浪?地震联合作用下，比选出的横向阻尼体系依旧表现出很好的减振效果，且阻尼器参数变化对减振性能的影响规律基本一致；为兼具减振与减震功能，推荐阻尼指数 α 取 0.8，阻尼常数 C 宜控制在 4 000~6 000 kN?（m/s）^-α 内。研究成果可为跨海斜拉桥的横向减振设计提供参考。

Abstract:

To study the lateral damping control of a cross-sea cable-stayed bridge under the combined action of wave and earthquake， taking a cross-sea cable-stayed bridge with a main span of 400 m as the engineering background， a finite element model of the entire bridge considering the water-structure interaction under the joint wave-earthquake action was established. The wave load on the high-piled deck pile group of the bridge substructure was also considered， and the earthquake hydraulic additional mass was solved based on the radiation wave theory. On this basis， the lateral vibration reduction system was constructed by using viscous dampers， and the control effects of viscous dampers under wave action and wave-earthquake combined action were discussed respectively. The results show that the lateral damping system with a viscous damper at the top of the auxiliary pier has a better damping effect under the action of waves alone， which can effectively restrain the lateral displacement of the main beam caused by wave load. Under the combined action of wave and earthquake， the selected lateral damping system still shows a good damping effect， and the influence of damper parameters on damping performance is basically the same. In order to have the function of both vibration damping and earthquake damping， it is recommended that the damping index α should be 0.8 and the damping constant C should be controlled within 4 000 ? 6 000 kN?（m/s）^-α . The research results can provide a reference for the lateral damping design of cross-sea cable-stayed bridges.