双边箱钢-砼组合梁悬索桥气动抑振措施试验分析

Experimental Study on Aerodynamic Vibration Suppression Measures for Suspension Bridge with Double-Sided Box Steel-Concrete Composite Beams

钢-砼组合梁由于其良好的力学性能被广泛应用于大跨度桥梁建设中,但作为一种典型的钝体断面,其气动稳定性较差,对风的作用较敏感,易产生涡振现象。依托南镇大桥项目,以双边箱钢-砼组合梁悬索桥为分析背景,采用风洞试验与CFD数值模拟的方法,研究对比单一、组合气动措施,包括封闭栏杆、改变检修车轨道位置、增加导流板、稳定板等,对该主梁原始断面的气动抑振性能进行分析。风洞试验表明,原设计双边箱钢-砼组合梁断面易引发涡振且出现竖弯与扭转耦合双峰涡振。当采用“封闭中央护栏+内移检修车轨道位置”组合气动措施时,可显著降低主梁的涡振振幅,制振效果显著。CFD数值模拟结果表明,双边箱钢-砼组合梁断面的涡振产生与上游边主梁及下游边主梁的涡脱尺寸有关,气动措施打碎涡脱尺寸有利于抑振。

Steel-concrete composite beams have been widely used in large-span bridges construction due to their excellent mechanical properties.However,as a typical blunt body section,their aerodynamic stability is poor,they have been sensitive to the action of wind,and prone to vortex vibration.Relying on the project of Nanzhen Bridge and taking the double-sided box steel-concrete composite girder suspension bridge as the research background,in this paper,wind tunnel test and CFD numerical simulation methods have been adopted to study and compare the single and combined aerodynamic measures,including closing railings,changing the track position of maintenance vehicles,adding deflectors,stabilizing plates,etc.,to study the aerodynamic vibration suppression performance of the original section of the main girder.Wind tunnel tests have shown that the cross-section of the originally designed double sided box steel concrete composite beam is prone to vortex vibration and exhibits a coupled bimodal vortex vibration of vertical bending and torsion.When using a combination of aerodynamic measures of“closed central guardrail+inward movement of maintenance vehicle track position”,the vortex vibration amplitude of the main beam can be significantly reduced,and the vibration control effect is significant.The CFD numerical simulation results indicate that the generation of vortex vibration in the cross-section of the double-sided box steel concrete composite beam is related to the vortex shedding size of the upstream and downstream main beams,and aerodynamic measures to break the vortex shedding size are beneficial for suppressing vibration.The research results of this paper can provide some reference for the design of aerodynamic vibration suppression measures of suspension bridge with double-sided box steel-concrete composite beams in the future.