一种改进的大跨度桥梁抖振响应时域分析方法

A MODIFIED TIME-DOMAIN METHOD FOR BUFFETING RESPONSE ANALYSIS OF LONG-SPAN BRIDGES

基于传统的统一描述方法,提出了一种改进的主梁气动力时域列式方法。该法通过校准方式引入修正系数以考虑主梁气动导数对自激效应的影响,通过引入气动导纳函数修正紊流风谱以考虑气动力沿主梁截面尺度的不完全相关性,从而在一定程度上突破了准定常假定的限制,克服了直接采用准定常假定而不加以修正所带来的问题。相对于列式复杂的主梁气动力非统一描述方法,该法仍保留了列式简单直观、物理意义明确的优点。采用所提出的方法对一独特的三塔大跨度斜拉桥进行了抖振响应分析,计算结果与风洞试验结果较为吻合,验证了该文方法的正确性和实用性。

Based on the conventional integrate expression approach, a modified time-domain formulation method is proposed for the calculation of aerodynamic forces acting on bridge girders. Both the effects of aerodynamic derivatives on self-excited forces and the partial correlated effects of aerodynamic forces over the chord of the girder section are taken into consideration in the present method by certain calibration techniques and appropriate aerodynamic admittance functions. The proposed method represents an important breakthrough in restrictions of the quasi-steady hypothesis, and the problems induced by the direct employment of such hypothesis without modification are solved to some extent in this study. The method remains its simplicity and straightforwardness as compared with the complicated theory employed in the non-integrate expressions for aerodynamic forces on bridge girders. Buffeting responses of a unique long-span cable-stayed bridge with three towers are investigated by the proposed method. The numerical results are agreeable with the wind tunnel test results on the whole, indicating the method developed in this paper is correct and practicable.