窄幅钢桁架悬索桥静动力稳定性能优化研究

Optimization on Static and Dynamic Stability of a Suspension Bridge with Narrow Steel Truss Girder

以某主跨420m、宽高比3.83的窄幅钢桁架悬索桥为研究对象,通过有限元计算分析和节段模型风洞试验,研究其静动力稳定性能。动力试验结果表明,主梁原始断面颤振稳定性不满足抗风要求。通过在主梁上设置下中央稳定板、水平导流板,对主梁进行气动优化设计研究。研究发现在7种优化方案中,方案3(高1m下中央稳定板)、方案5(宽1m水平导流板)和方案7(高0.75m下中央稳定板和宽0.5m水平导流板组合)均能有效改善主梁的颤振稳定性能。考虑到优化措施的经济性以及施工便利性,推荐采用方案3。同时,在静力试验获得静力三分力系数的基础上,利用非线性静风分析原理对优化后大桥的静风稳定性能进行分析,研究结果表明,大桥的静风稳定性能满足规范要求。

Taking a suspension bridge of a 420m main span with steel truss girder and width/height ratio of 3.83as study object,the static and dynamic stability of the bridge is analyzed by element analysis and sectional model wind tunnel test.The dynamic test results show the flutter stability of the original girder did not meet the requirement of wind-resistance design.In such situation,aerodynamic optimization design of the original girder has been discussed by lower central stabilizer and horizontal guide plate.The study finds that Scheme 3(the height 1mlower central stabilizer),Scheme 5(the width 1mhorizontal guide plate)and Scheme 7(the combination of the height 0.75mlower central stabilizer and the width 0.5mhorizontal guide plate)can improve the aerodynamic stability of the girder.Taking into account the optimization of the economy and the convenience of the construction,Scheme 3is recommended.At the same time,based on the static three component coefficient of static test,the aerostatic stability of the bridge has been analyzed using nonlinear static wind analysis principle,the results show that the aerostatic stability of the bridge can meet the requirements of specification.