板桁结合加劲梁悬索桥颤振稳定措施试验研究

Experimental Study on the Flutter Stability Countermeasures of a Suspension Bridge with a Stiffened Plate-truss Composite Girder

为了研究板桁结合加劲梁悬索桥的颤振稳定性,以国内某大跨悬索桥为背景,通过节段模型风洞试验分别研究了上、下中央稳定板以及水平稳定板的制振效果,并考察了阻尼比对主梁颤振临界风速的影响,最后对比研究了原设计方案和安装上中央稳定板的板桁结合加劲梁的三分力系数。研究结果表明:上中央稳定板可以有效抑制板桁结合加劲梁颤振,且颤振临界风速增长率随稳定板高度的增加呈非线性变化;安装于桥面下方的下中央稳定板不能改善主梁的颤振性能,但安装于下平联处的下中央稳定板可以在一定程度上提高主梁的颤振临界风速;安装于桥面板边缘处的水平稳定板会恶化主梁的颤振稳定性;将上、下中央稳定板联合使用时主梁可以取得更好的颤振性能。阻尼比对以扭转颤振为主的板桁结合加劲梁具有显著影响;安装与栏杆等高的上中央稳定板在小攻角范围内对主梁三分力系数的影响很小。

In order to study the flutter stability of a suspension bridge with a plate-truss composite stiffened girder,a long-span suspension bridge built in China was taken as the background,and the flutter mitigation effects of upper and lower central stabilizers and horizontal stabilizer were studied,respectively,through the section model wind tunnel test.Then,the effect of the damping ratio on the flutter critical wind speed of the main girder was investigated.Finally,the three-component aerostatic force coefficients of the plate-truss stiffened girder were compared between the original design and the girder with the upper central stabilizer.The results show that the upper central stabilizer can effectively suppress the flutter of the plate-truss stiffened girder,and the growth rate of the critical wind speed varies nonlinearly with the increase of the height of the stabilizer;the lower central stabilizer installed under the bridge deck cannot improve the flutter performance of the main girder,but when it installed at the lower lateral combination of the girder can increase the flutter critical wind speed to some extent.The flutter stability of the main girder is deteriorated by the horizontal stabilizer installed at the upper edge of the deck;the main girder can achieve better flutter performance when the upper and lower central stabilization plates are used together.Damping ratio has an obvious effect on the flutter of the platetruss stiffened girder with the main feature of torsional vibration,and the installation of upper central stabilizer with the same height as the railings has little effect on the three-component aerostatic force coefficients of the girder at small angles of attack.