【摘要】 普立特大桥是一座山区大跨悬索桥,为高柔的风敏感结构.在分析抗风性能时,利用ANSYS软件,建立了普立特悬索桥的三维有限元模型,分析了该模型的动力特性,根据Deodatis的谐波合成法模拟了桥梁的随机脉动风场并进行了检验,然后基于准定常理论计算了作用于模型上的抖振力时程,自激力以单元气动刚度及阻尼矩阵的形式在ANSYS中以Matrix27矩阵输入,最后由时程分析求得桥梁在考虑与不考虑自激力作用时的抖振响应.计算结果表明考虑自激力后主要改变了桥梁振动的平衡位置和在部分方向振动中起到正阻尼作用,为同类桥梁的抗风设计计算提供参考.更多还原

【Abstract】 PLT Bridge is a long-span suspension bridge in the hills which is a high-rise flexible and wind sensitive structure. Thus, the wind-resistant capacity must be considered for the bridge. The 3D finite element model of bridge was established by using ANSYS software, and its dynamic characteristics were then obtained. With spectral representation method proposed by Deodatis, fluctuating wind fields for the bridge were generated and validated. Then, the time-history of buffeting force was calculated by using the quasi-steady theory. The self-excited forces are considered in form of the element aerodynamic damping matrix and aerdynamic stiffness matrix with Matrix 27 in ANSYS. Finally, buffeting analysis with and without considering self-excited forces in time domain were calculated by using time history analysis. The results show that, when considering self-exicted forces, it mainly changes the equilibrium position of bridge vibration and the positive damping effect can be found in some directions of the bridge. This study can provide reference for the wind-resistant design of similar bridges.更多还原