大跨径自锚式悬索桥气动参数的敏感性分析

基于桥梁多振型耦合的气弹性理论,建立了基于特征值问题的气动参数敏感性分析方法,并结合目前国内最大跨度的独塔和双塔自锚式悬索桥的风洞试验资料,分别探讨截面形状、气动阻尼、模态耦合、颤振导数、施工过程等对桥梁气动性能的影响.主要的分析结果表明:对于具有扁平流线型钢箱梁的自锚式悬索桥,其颤振临界风速的计算结果比较接近于薄平板,且绝大部分能量都集中到扭转振型上,表明对颤振发生时起主导作用的是扭转模态;结构阻尼的增加在一定范围内对抑制结构响应所起的作用明显;加劲梁的侧向摇摆运动对其竖向响应的影响非常显著.这些特点均表明此类自锚式悬索桥的空气动力性能与斜拉桥更为接近.图3,表4,参9.

Sensitivity Analysis of Aerodynamic Parameter for Long-span Self-anchored Suspension Bridges

Based on the aeroelastic analysis of bridges multimode approach,sensitivity analysis method was established.The effect factors were analyzed on the aerodynamic parameter in the structure of a self-anchored suspension bridge through the eigenvalue theories,such as sectional configuration,aerodynamic damp,modal couple,flutter derivatives and construction procedure from the results of wind-tunnel test of the longest span single and double pylons.It indicate that for self-anchored suspension bridges with flat streamlined steel box girder,the results of the flutter critical wind velocity are close to that of the thin flat plate and major energy focuses on the first torsion model,which means that torsion modal is the key factor.The increasing of structural damp will suppress buffet response in a given range and the lateral swing of stiffening girder will influence the vertical response.All these characteristics show that aerodynamic property of self-anchored suspension bridges approaches that of cable-stayed bridges.3figs.,4tabs.,9refs.