钢桁架梁悬索桥抖振响应影响因素分析

Influence Factors Analysis of Buffeting Response of Suspension Bridge of Steel Truss Beam

用等效的单主梁模型分析钢桁架悬索桥的抖振,分析各种因素对钢桁架悬索桥抖振响应的影响。由于桁架桥构件之间气动干扰的复杂性,在风洞试验时得到的气动力系数表征的是断面的气动特征,而非杆件的气动特征。因此,风振的分析需要建立静力刚度和动力特性与桁架梁等效的单梁有限元模型。通过调整等代梁的刚度和集中质量可以实现等效。分析结果表明:在设计基准风速下,大变形和自激力对抖振起抑制作用,有效风攻角使得抖振响应变大,且静风对风攻角的改变起主要作用。自激力影响程度最大,静风和有效风攻角的影响程度其次,大变形的影响最小。

The equivalent single beam model is adopted to analyze the buffeting of steel truss beam suspension bridge,and to analyze the influence of some factors on its buffeting response.Because of the complexity of the pneumatic interference among the structural members of the truss bridge,the aerodynamic coefficient character attained in the wind tunnel laboratory is the pneumatic character of section,instead of the member.Therefore,the single beam finite element model is needed for analyzing the wind buffeting that is equivalent to truss beam in static rigidity and dynamic characters.The equivalent beam is realized by adjusting the rigidity of single beam and lump mass.Results show that large deformation and self excitation force restrain buffeting,effective wind attack angle makes buffeting response larger,and static wind load plays the main role to change the wind attack angle under the design reference wind speed.The influence degree of self excitation force is maximum,the static wind action and effective wind attack are secondary and the large deformation is minimum.