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深水大跨刚构桥在地震荷载作用下,水下结构部分与周围水体之间相互作用必然导致结构受到水体运动产生的动水力的作用。在已有Morison动水理论的基础上,利用深水大跨桥梁在动力荷载作用下的动水力简便计算方法,以某一大跨深水刚构桥为对象,分析了动水对刚构桥结构动力特性和地震反应的影响。主要结论有:水与刚构桥下部结构相互作用将使刚构桥自振周期有所增大,其中有水状态下桥梁第1阶自振周期相对无水时增大了4.72%;地震作用下动水对刚构桥结构内力有显著的影响,使桥墩底部弯矩最多增大了76.57%,平均增大了28.72%。并且动水使桥墩顶部位移平均增大了18.41%。且不同类型地震作用时,动水对桥梁动力响应的影响不尽相同。在深水大跨刚构桥进行抗震设计中,动水对桥梁动力响应的影响不容忽略。
The deep-water long-span rigid frame bridge under earthquake load, the interaction between the underwater structure and the surrounding water will inevitably lead to the structure by the hydrodynamic movement of water. On the basis of Morison hydrodynamic theory, a simple method of dynamic and hydraulic calculation of deep-water and long-span bridges under dynamic load is taken as an example to analyze the dynamic effect of dynamic water on the rigid-framed bridge structure Characteristics and seismic response. The main conclusions are as follows: the interaction between water and the substructure of rigid frame bridge will increase the period of natural vibration of rigid frame bridge, and the first cycle of natural vibration increases by 4.72% Under moving water, the internal force of rigid-framed bridge structure has a significant impact, so that the bending moment at the bottom of pier increases by up to 76.57%, an average increase of 28.72%. And the hydrodynamic displacement of the pier top increased by an average of 18.41%. Different types of earthquakes affect the dynamic response of bridge. In seismic design of deep-water long-span rigid frame bridge, dynamic water influence on bridge dynamic response can not be neglected.