【摘要】 为研究大跨斜拉桥成桥与施工状态的风致抖振响应,分别采用时域和频域方法对一座典型大跨斜拉桥的成桥状态、施工最大双悬臂与最大单悬臂状态进行了数值计算。采用改进的谐波合成法模拟桥梁结构的随机脉动风场,基于有限元编程,实现了考虑自激力的斜拉桥抖振时域分析,使用多模态耦合分析方法进行斜拉桥的频域抖振分析。分析结果表明:在主梁设计基准风速下,成桥状态和施工状态的横桥向和扭转角抖振位移均较小,施工最大双悬臂中跨悬臂端点竖桥向抖振位移较大,在施工中应妥善处理;成桥与施工状态下的主塔塔顶抖振位移均较小,施工过程中可以不考虑主塔顶部的位移控制;基于合理模拟风场的时域计算方法,能够考虑各种非线性因素,能够较好地反映斜拉桥的抖振响应;不考虑气动导纳的频域计算会夸大斜拉桥的抖振响应,考虑Sears函数作为气动导纳的频域计算方法会低估斜拉桥的抖振响应。更多还原

【Abstract】 To study the wind-induced buffeting response of long-span cable-stayed bridge in construction and completion states,the buffeting responses of bridge completion state,the longest double-cantilever stage and the longest single-cantilever stage of a typical long-span cable-stayed bridge are calculated by time domain and frequency domain methods. The improved harmonic synthesis method is adopted to simulate the random wind turbulence field for the bridge,and the time domain analysis of the cable-stayed bridge buffeting considering self-excited force is realized based on finite element program. The frequency domain analysis of the bridge buffeting is conducted using multimode coupled analysis method. The result shows that( 1) the transversal and torsion angle buffeting displacement of the bridge in completion and construction states are relatively small,while the vertical buffeting displacement of central span cantilever end in the longest doublecantilever stage is relatively larger,which should be properly handled in the construction;( 2) it is no need to take any measure for the pylon top in construction state because its buffeting displacement is relatively small in construction and completion states;( 3) the time domain analysis method based on reasonable wind turbulence field simulation can consider all kinds of nonlinear factors and preferably reflect the buffeting response of longspan cable-stayed bridge;( 4) the frequency domain analysis without considering aerodynamic admittance would overstate the buffeting response of cable-stayed bridge,the frequency domain analysis considering Sears function as aerodynamic admittance may underestimate the buffeting response of the bridge.更多还原