桥梁非线性二维静风稳定性分析模型研究

Study of nonlinear 2D aerostatic stability model for bridges

传统的二维静风失稳模型没有考虑结构扭转恢复力以及气动力与攻角的非线性函数关系，已不能满足实际工程建设的要求．为提高计算精度，通过引入实测扭矩一转角函数关系并将升力矩按泰勒级数展开至二次项，提出一种改进的二维静风失稳模型，在此基础上推导出静风扭转发散临界风速计算公式．运用该方法对一座高风速区大跨度钢箱连续梁桥在施工过程中最大悬臂状态的静风失稳临界风速进行计算，并将计算结果与传统的二维静风失稳模型和三维静风失稳模型进行对比．结果表明：所提出的改进二维静风失稳模型具有很好的计算效率和精度，研究成果可以应用于工程实践．

Non-linearity characters of torsional resilience and aerodynamic force with respect to the angle of attack were not considerably taken into consideration in the typical 2D model of aerostatic instability, which cannot meet the engineering application requirements. In order to increase the calculation accuracy, an improved method is presented in this paper through considering the function of the torsional moment respect to rotation angle and the second-order Taylor expansion for the lift moment. The critical wind speed of torsional divergence of a steel-box continuous girder bridge, which is located in high wind speed region at the longest cantilever construction stage, are calculated using the improved method. Compared to the result of the typical 2D and the 3D model aerostatic instability, the result of improved method has a well efficiency and accuracy and is valuable in engineering application.