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、颤振导数等对桥梁气动性能的影响.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.以上特点表明自锚式悬索桥的空气动力性能与斜拉桥更为接近.
A method for analyzing the sensitivity of critical flutter wind velocity with respect to aerodynamic parameters was formulated based on the characteristic equation of the motion of flutter. By using the wind tunnel testing data of two self-anchored long-span suspension bridges, one with mono tower and the other with double towers, the effects of the geometrical configuration of the deck cross section, aerodynamic damping, modal coupling and flutter derivatives on the aerodynamic performance of the two bridges were studied. It is shown that the critical flutter wind velocity of suspension bridges with streamlined deck cross section is fairly close to that of thin-plate-decked bridge, and that the torsional modes have predominant energy contribution in critical flutter state and are thus critical to flutter. The structural damping has a notable effect in the control of the structural response. These observations have concluded that the aerodynamic performance of self-anchored suspension bridges is similar to that of cable-stayed bridges.