波流作用对深水桥梁地震响应的影响分析

Influence of Wave-Current Interaction on Seismic Response of Deep-Water Bridge

为研究波流作用对深水桥梁下部结构地震响应的影响,采用ANSYS-CFX软件建立圆形截面桩-水耦合数值模型,计算波流与地震作用下桩的位移和应力响应,分析不同波流(相对水深比、相对流速比、波陡、周期、方向角和相位角)作用下的地震响应。结果表明:随着水深的增加,波流对地震响应的影响增大;相比弱流强波,强流弱波对地震响应影响要显著;波高对地震响应影响与波高大小呈线性关系;波流荷载并不总是起到加大地震响应的作用,波流与地震作用方向角和时间相位差会随机削弱或加强地震响应;波流对地震响应影响可达56.5%,在跨海深水桥梁抗震分析时波流作用的影响不容忽视;6个因素中,周期影响最显著,准确地概化波浪有效周期对结构设计安全至关重要。

To study the influence of wave current interaction on the seismic response of the substructure of deep water bridge, the ANSYS CFX software was used to establish the numerical model of round section pile water coupling, to calculate the displacement and stress response of the piles under the action of wave current interaction and earthquakes and analyze the seismic response under different wave current interaction, including different relative water depth ratio, relative wave speed ratio, wave steepness, period, direction angle and phase angle. The results show that the influence of wave current interaction on the seismic response of structure is intensified as the increase of water depth. Compared with the weak currents and strong waves, the influence of strong currents and weak waves on the seismic response is more distinctive. There is a linear relation between the influence of the wave height on the seismic response and the scale of the wave height. The wave and current loads do not always intensify the seismic response of the bridge structure. The direction angle of the waves and currents and seismic action and the time phase difference can stochastically reduce or enhance the seismic response. The influence of the wave-current interaction on seismic response can reach 56.5%, thus, the influence of wave-current interaction should not be ignored during the seismic analysis of sea crossing deep water bridge. Among these six factors, the influence of time period is the most significant. Therefore, the correct generalization of effective wave period is vital to the design safety of bridge structure.