考虑特征紊流影响的大跨桥梁静风稳定分析方法

为了研究特征紊流抖振力对大跨度桥梁静风稳定性的影响,提出了特征紊流气动力模型,建立了考虑特征紊流影响的大跨度桥梁静风稳定分析方法。通过采用风洞实测气动力系数谱模拟特征紊流气动力系数时程,利用动力有限元算法计算了西堠门大桥的位移响应,分析了特征紊流对其静风稳定的影响。结果表明:结构仅仅是在平衡位置附近作微幅振动,特征紊流对西堠门大桥静风稳定临界风速和失稳形态没有明显影响。主要是因为特征紊流是窄带的随机过程,其能量主要集中在某一个频率附近,对西堠门大桥而言,该频率远高于结构的基频,所以特征紊流气动力未能激起较大的位移响应。

AN APPROACH FOR ANALYZING THE EFFECT OF SIGNATURE TURBULENCE ON THE AEROSTATIC STABILITY OF LONG-SPAN BRIDGES

In order to study the effect of signature turbulence on the aerostatic stability of long-span bridges, a model for signature turbulence aerodynamic-force was proposed. An approach for analyzing the effect of signature turbulence on the aerostatic stability was also put forward. The time-histories of aerodynamic force coefficients were simulated based on the spectra gained in wind tunnel tests of a sectional model. The displacement responses of Xihoumen Bridge were then calculated using the dynamic FEM method. The results show that the bridge deck vibrates with a small amplitude in the vicinity of an aerostatic equilibrium configuration, which means the effect of signature turbulence on aerostatic stability is unremarkable. Signature turbulence is a narrow-band random process. The energy mainly concentrates near a certain frequency which is much higher than the fundamental frequency of Xihoumen Bridge. As a result, signature turbulence cannot induce a vibration with a large amplitude.