基于压重块型TMD的大跨度斜拉桥减震控制

Seismic control of a long-span cable-stayed bridge using TMD-type counterweight

调谐质量阻尼器(TMD)能对大跨度桥梁振动进行有效控制,但安装TMD所带来的附加荷载将显著增加主梁的静载挠度,极大地抑制了TMD桥梁减振中的广泛应用。为此,提出了一种基于压重块型TMD的大跨度斜拉桥减震控制方法,该法针对大跨度斜拉桥的结构特点,将边跨的压重块设计并改装成压重块型TMD,以控制主梁的竖向振动。以边跨配置了压重块、主跨为1088m的苏通大桥参照,分别设计了有辅助墩和无辅助墩的两种大跨度斜拉桥,并对比分析了采用压重块型TMD前后大桥关键截面的地震响应。研究结果表明:在大跨桥梁无辅助墩时,压重块型TMD能在保持传统压重块功能的同时,显著降低结构的振动响应,减震率最高可达21%;而在设辅助墩时,压重块型TMD的减震率相对较低,最大值不足10%。

Tuned mass damper（TMD）can effectively control the vibration of the long-span bridges.However,the additional load caused by installation of TMD will significantly increase the static deflection of the main girder,which greatly limits the application of TMD in the bridge vibration control.Therefore,a method for seismic control of long-span cable-stayed bridge based on counterweight-type TMD is presented in this paper.According to the structural characteristics of a long span cablestayed bridge,the counterweight at the side-span is designed and converted into one kind of TMD to control the vertical vibration of the main girder.Taking the Sutong Bridge with a main span of 1088 mand counterweight at the side span as the reference,two long-span cable-stayed bridges are designed.One is with auxiliary pier and the other is without auxiliary pier at the side span of the bridge.For each of the two bridges,the seismic responses of the key sections before and after using the counterweight-type TMD are compared and analyzed.The results indicate that when there are no auxiliary piers in the long-span bridges,the counterweight-type TMD has obvious effects on reducing the vibration of the main girder while maintaining the other functions of the traditional counterweight.And the highest vibration mitigation rate can reach 21%.However,the vibration mitigation rate is relatively low and the maximum value is less than 10% when the auxiliary piers are used.