基于谱分解法的自锚式悬索桥桥梁风致抖振计算分析

自锚式悬索桥是一种大跨度柔性结构体系,该桥型经受脉动风作用时容易发生较大的抖振响应,对于该种桥型进行风致抖振的研究探讨具有较强的实际意义。以自锚式悬索桥武汉汉江六桥为工程实例,进行风致抖振分析。具体分析流程为:通过计算流体力学软件对桥梁进行气动分析,得到桥梁抗风分析方程中的重要参数静力三分力系数。通过对桥址处风场资料的分析,采用规范规定的风谱密度函数,利用谱分解法将脉动风谱转换成脉动风时程,同时结合准定常气动理论将风时程转换成风力时程实现气动力的时域化。利用有限元软件建立桥梁的空间模型并分析自锚式悬索桥动力特性。通过自编数值程序和有限软件的结合将风力时程加载在桥梁模型上,实现桥梁在时程风力作用下抖振响应的数值模拟。其计算结果表明:该桥在风致抖振作用下性能良好,结构具有良好的气动性。结合计算流体力学软件、数值分析软件、有限元软件的桥梁抗风计算方法和模式,可以在其他自锚式悬索桥风致抖振计算中参考使用。

Buffeting Analysis of Self-anchored Suspension Bridge Wind Resistance Based on Spectral Representation Method

Since long span self-anchored suspension bridge is a large-span flexible structural system,large buffeting response tends to occur due to fluctuating wind,and the study of this kind of bridge with wind-induced buffeting has great practical significance. This paper focuses on wind-induced buffeting analysis of Wuhan Hanjiang No. 6 bridge of self-anchored suspension bridge. The specific analysis process is shown as the followings: by using the CFD software of the bridge aerodynamic analysis of bridge,three static component coefficients in wind resistance analysis of the important parameters in the equations are obtained. With the analysis of the wind field data related to bridge location and the adoption of the codes specified wind spectral density function,the fluctuating wind spectrum is transferred into fluctuating wind time-history data through spectral representation method. The fluctuating wind timehistory date can be switched into wind force time-history data based on quasi-steady aerodynamic theory.Finite element models of the bridge are developed using a widely-used software to analyze dynamic characteristics of the bridge. Combining the numerical procedures with finite element software to put the wind load on FE model,the study conducts the numerical simulation of the bridge buffeting response under wind force. The results show that the bridge under the wind-induced shaking up has good performance and good pneumatic structure. The wind resistance calculation method and mode with the combination of the computational fluid dynamics software,the numerical analysis software and the finite element software of bridge can be used as reference for the calculation of other self-anchored suspension bridge buffeting.