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针对非对称独塔斜拉桥结构刚度不对称以致其风振响应异于传统对称斜拉桥的状况,以位于沿海地区的某非对称独塔斜拉桥为工程背景,对大跨度斜拉桥抖振响应等效静力风荷载进行了深入研究。首先,采用有限单元法分析了结构的动力特性;其次,进行了节段模型风洞试验,并采用同时考虑自激力和抖振力的抖振计算模型对结构的抖振响应进行了分析,并在上述工作的基础上,以结构的抖振响应为等效目标,推导了基于结构振型的抖振等效静力风荷载计算方法;最后,将该方法与精确抖振响应计算结果进行了比较。结果表明:所提出的基于振型的抖振等效静力风荷载计算方法可以同时考虑结构不同部位的抖振响应,与中国《公路桥梁抗风设计规范》中的方法相比,能够体现等效静力风荷载与结构振型和质量分布相关的特性;该方法的计算结果与精确抖振响应极值相比,在关键部位的误差均小于10%,精度满足工程计算的要求;对于柔性大跨度桥梁抖振响应等效静力风荷载计算,建议优先采用该方法。
Aiming at the asymmetric structure stiffness of asymmetrical single-pylon cable-stayed bridge, its wind-induced vibration response is different from that of the traditional symmetrical cable-stayed bridge. Based on the engineering background of an asymmetrical single-pylon cable-stayed bridge located in the coastal area, Dithering response Equivalent static wind load was studied in depth. First, the finite element method is used to analyze the dynamic characteristics of the structure. Secondly, the wind tunnel test of the segmental model is carried out and the chattering response of the structure is analyzed by using the chattering calculation model considering both self-excitation and buffeting forces. On the basis of the above work, based on the chattering response of the structure as the equivalent target, the method of calculating the equivalent static wind load based on the mode shape of the chattering vibration is deduced. Finally, the calculation results of this method and the accurate chattering response A The results show that the proposed vibration mode equivalent buffeting equivalent static wind load calculation method can consider the chattering responses of different parts of the structure at the same time. Compared with the method of “Design Code of Wind-resistant Bridge for Highway and Bridge” Compared with the extremum of the precise chattering response, the error of these methods is less than 10% at the critical positions, the accuracy meets the requirements of engineering calculation. For the flexibility Large-span bridge buffeting response Equivalent static wind load calculation, it is recommended to give priority to the method.