基于节段模型测振试验的大跨度桥梁抖振响应预测

传统大跨度桥梁抖振响应计算是基于颤抖振理论，并借助节段模型测压或测力试验进行，目前鲜有通过节段模型测振试验实现桥梁抖振响应预测的报道。基于抖振分析理论推导了考虑三维效应的两波数抖振力，并根据综合传递函数的概念提出了基于节段模型测振试验的大跨度桥梁抖振响应预测方法。以某流线型箱梁悬索桥为例，通过节段模型及全桥气弹模型试验研究了该预测方法的精度及可行性。结果表明:结构展宽比对综合传递函数识别精度存在影响，展宽比越大，识别精度越高。即使在湍流积分尺度并未远大于结构宽度的前提下，增大模型展宽比可有效减弱三维效应的影响。基于节段模型测振试验识别综合传递函数的方法可用于大跨度桥梁抖振响应的预测，该方法预测结果偏于保守。

PREDICTION OF BUFFETING RESPONSE OF LONG-SPAN BRIDGES BASED ON SECTIONAL MODEL VIBRATION TEST

The traditional buffeting response calculation of long-span bridge structures is based on the flutter and buffeting theory, which is conducted by means of sectional model pressure or force measurement test. At present, there is no report on the prediction of buffeting response of long-span bridges through sectional model vibration test. Based on the buffeting analysis theory, the two-wavenumber buffeting force considering the three-dimensional effect is derived. The prediction method of the long-span bridge buffeting response based on the sectional model vibration test is proposed based on the concept of integrated transfer function. Taking a suspension bridge with streamlined box girder as an example, the accuracy and feasibility of the prediction method are investigated through wind tunnel tests of a sectional model and a full-bridge aeroelastic model. The results show that the structural aspect ratio has a certain influence on the identification accuracy of the integrated transfer function. A larger aspect ratio leads to a higher identification accuracy of the integrated transfer function. Even if the turbulence integral scale is not much larger than the structure width, increasing the model aspect ratio can effectively reduce the influence of the three-dimensional effect. The method of identifying the integrated transfer function through the sectional model vibration test can be used to predict the buffeting response of long-span bridges with conservative prediction results.