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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。
In order to study the wind-induced buffeting response of long-span cable-stayed bridge under construction and construction conditions, the state of bridge construction, the construction of the largest double cantilever and the largest single-cantilever state of a typical long-span cable- Numeral Calculations. The improved harmonic synthesis method is used to simulate the random fluctuating wind field of the bridge structure. Based on the finite element programming, the buffeting time-domain analysis of the cable-stayed bridge considering the self-excitation is realized. The multi-modal coupling analysis Domain Buffeting Analysis. The analysis results show that at the reference design wind speed of the main girder, the lateral and torsional vibrational displacements in the bridge construction and the construction state are both small, and the maximum vertical double-arm cantilever construction cantilever with large displacement. Construction should be properly handled; into the bridge and under construction state of the main tower overhead buffeting displacement are small, the construction process can not consider the displacement control of the top of the tower; based on a reasonable simulation of the wind field in the time domain can be considered Various non-linear factors can well reflect the chattering response of cable-stayed bridges; the frequency domain calculation without considering the aerodynamic admittance will overstate the chattering response of cable-stayed bridges, and the Sears function is considered as the frequency domain calculation method of aerodynamic admittance Will be underestimated cable-stayed bridge buffeting response.