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大跨度桥梁发生静风失稳的临界风速可能低于动力失稳的临界风速。结合斜拉桥的结构特点,探讨了已有的非线性失稳分析方法,提出了一种静风失稳的复合标准判断方法,基于MSC.MARC和Python脚本语言,综合考虑结构几何非线性和静风荷载非线性影响,探讨了大跨度斜拉桥空气静力失稳特性。结果表明:升力系数和力矩系数在大跨桥梁静力失稳全过程分析中起到关键作用;风速达到或接近失稳临界风速时,大跨度斜拉桥梁的结构非线性问题十分突出,静力失稳表现为十分明显的弯扭耦合形态。
The critical wind speed of static wind instability of long-span bridges may be lower than the critical wind speed of dynamic instability. Combined with the structural characteristics of cable-stayed bridge, the existing methods of nonlinear instability analysis are discussed, and a composite standard judgment method of static wind-wind instability is proposed. Based on the MSC.MARC and Python scripting languages, the geometrical nonlinearity and The nonlinear effect of static wind load is discussed and the aerostatic instability of long-span cable-stayed bridge is discussed. The results show that the lift coefficient and moment coefficient play a key role in the whole process analysis of large-span bridges’ static buckling. When the wind speed reaches or approaches the critical wind speed, the structural nonlinearity of long-span cable-stayed bridges is very serious. The instability manifests itself as a very pronounced bending-torsional coupling.