桥面横向连接对双幅桥梁抗风性能的影响

Effects of a cross diaphragm on the wind-resistant performance of twin parallel deck bridges

以泉州海湾桥两种结构形式双幅桥面主梁方案为背景,通过数值计算研究了两种双幅桥面结构的结构动力特性;通过风洞试验研究了桥梁颤振稳定性和涡激共振性能。研究结果表明,是否存在桥面横向连接对双幅桥的结构固有动力特性影响较大,无横向连接双幅桥面较有横向连接双幅桥面的模态特征更复杂,其竖弯和扭转基频均会出现双幅桥面同向运动和反向运动两种模态;在气流作用下,无横向连接双幅桥面和有横向连接双幅桥面的主梁运动形式不同,两种结构形式双幅桥面的颤振稳定性能和涡激共振性能存在显著差异,双幅有横向连接主梁的气动稳定性优于双幅无横向连接主梁,但前者的涡激共振性能要差于后者。

Taking the two plans of the Quanzhou Bay Bridge as an example,the modal characteristics of the two type structures were investigated by numerical analysis.The aerodynamic stability,vortex-induced vibration property of the bridge deck(s)were investigated via wind tunnel tests.The results show that the two plans of the twin-deck bridge have notable differences on the modal characteristics.Comparing to the plan of twin decks with a cross diaphragm,the twin decks without a cross diaphragm have much more complicated modal features.It has two types of bending and torsion mode in which the decks move in the same direction or in the opposite direction.The two different types of decks will deform dissimilarly in the flow,which result in the different aerodynamic stability and vortex-induced vibration performance of the two different structures.The twin decks with a cross diaphragm have better aerodynamic stability performance than the decks without a cross diaphragm;however,for the performance of vortex-induced vibration,the former is worse than that of the latter.