深水桥墩地震响应研究现状与展望

Research status and prospect of seismic response of deep-water bridge pier

分析了地震激励下水-深水桥墩动力相互作用,总结了动水压力作用机理、地震动水压力的计算方法和水-结构动力相互作用分析方法,研究了深水桥墩地震响应特征和影响因素以及水下振动台试验进展,并对比了各国规范中动水压力计算方法。研究结果表明:动水压力降低桥墩自振频率,增大桥墩地震响应,其影响在桥梁的抗震设计中不可忽略;现有研究采用的桥墩形式较为简化和单一,建议开展更多以桥墩体系、桥梁体系为对象的深水桥梁地震响应研究;对于地震作用下动水压力计算,目前各国规范多基于Morison方程,但对其适用范围尚不明确,应深入研究Morison方程的适用范围、修正方法与准确便捷的地震动水压力计算方法;目前水下振动台试验大多集中在动水压力对桥梁下部墩桩地震响应的影响上,响应大多在弹性范围内,应进一步研究在大震作用下深水桥墩的非线性响应与破坏模式;目前针对深水桥墩在地震和波浪联合作用下的动力响应研究较少,应深入研究在地震、波浪、海流联合作用下深水桥墩与水的相互作用机理;目前缺乏对全桥结构的地震响应研究,应开展深水桥梁全桥分析与多子台水下振动台试验。

The dynamic interaction between deep water bridge piers and surrounding water under seismic excitation was analyzed.The mechanisms and calculation methods of hydrodynamic pressure and the analysis methods of water-structure dynamic interaction were summarized.The seismic response characteristics and the influence factors of deep-water bridge piers and the research progress of underwater shaking table test were studied.The calculation methods of hydrodynamic pressure in national standards were also discussed.Research result indicates that the influence of hydrodynamic pressure on the seismic response of bridge pier cannot be neglected in the seismic design of bridges,because it reduces the natural frequency of bridge pier and increases the seismic response of bridge pier.The forms of the bridge piers adopted in current research are simplified and limited.The seismic response of deep-water bridge based on the bridge pier system and bridge system should be studied.In terms of calculation of hydrodynamic pressure under seismicity,most of the current national standards are based on the Morison equation,but the application range is still unclear.It is necessary to carry out the in-depth study on application range of Morison equation and revised methods and to propose an accurate and convenient method for calculating hydrodynamic pressure under seismicity.Currently,the underwater shaking table tests mostly focus on the influence of hydrodynamic pressure on the seismic responses of bridge piers and piles,and the responses are mostly within the elastic range.The nonlinear responses and failure modes of deep-water bridge piers under severe seismicity should be studied.There are few studies on the dynamic responses of deep-water bridge piers under combined seismicity and wave action,and the interaction mechanisms between bridge piers and water under combined action of seismicity,wave and current should be researched out in depth.There is a lack of research on the seismic response of whole bridge structure.It is necessary to carry out whole deep-water bridges analysis and multi table underwater shaking table test.4 tabs,2 figs,72 refs.