紊流积分尺度对典型桥梁断面静力#br# 系数影响规律的风洞试验研究

为研究紊流积分尺度对典型桥梁断面静力系数影响的规律，文章通过在风洞中模拟紊流对典型桥梁断面进行测力试验。借助尖塔，格栅等方式模拟紊流的传统试验方法，难以模拟实际风场中的大紊流积分尺度。文章采用自主研制的主动控制翼栅，有效增大试验中风场的紊流积分尺度，通过控制主动控制翼栅的振动频率产生不同紊流积分尺度的风场。对单箱梁、双箱梁、桁架梁、边主梁、边箱梁五种典型桥梁断面在紊流下和均匀流下的静力系数进行了测定，其中紊流由主动控制翼栅产生。将五种典型桥梁断面在紊流下的静力系数和均匀流下的静力系数进行对比分析，结果表明在大紊流积分尺度下，阻力系数随紊流积分尺度增大而增大，且小于均匀流下的阻力系数值。结果也表明，在均匀流来测定桥梁断面静力系数对于实际工程应用是偏于安全的考虑，因此建议进行节段模型测力试验时，在均匀流中进行。

Wind tunnel tests on the influence of turbulent integral scale on #br# aerostatic coefficients of typical bridge section

In order to study the influence of turbulent integral scale on the aerostatic coefficients of common bridge sections, force measurement tests were performed on typical bridge sections by simulating turbulence in wind tunnels. It is difficult for the traditional test method of simulating turbulence by means of spires and grilles to simulate the great integral turbulent scale in actual wind field. In this work, the turbulent integral scale of the experimental wind field is effectively increased by using the active control grid, and the wind fields of different turbulent integral scales are generated by controlling the vibration frequency of the active control grid. The aerostatic coefficients of five typical bridge cross-sections, namely, single box girder, twin-box girder, truss girder, edge main girder and side-box girder, were measured under turbulent flow and uniform flow. The aerostatic coefficients of five typical bridge cross-sections under turbulent flow and uniform flow are compared and analyzed. The results showed that under different turbulent integral scales, the resistance coefficient increases with the increase of turbulent integral scale, and it is less than the value under the uniform flow. Additionally, the results also show that to be conservative for design of actual project, the static coefficient shall be determined under the uniform flow. Therefore, the aerostatic force test is suggested to be carried out under the uniform flow.