中文摘要：

型钢-混凝土开口Π型主梁断面是目前斜拉桥中广泛应用的一种形式,由于其钝体断面特性,容易出现风致振动问题,需要对其断面进行优化.以某主跨300 m的斜拉桥为工程背景,通过一系列节段模型风洞试验,对3种Π型结合主梁断面进行风洞试验研究,比较了它们的颤振和涡振性能,得到了一些有益结论：在很多情况下,气动外形对Π型主梁颤振和涡振性能的影响不同,在气动选型中应综合考虑;与均匀流场相比,紊流场的脉动分量抑制了漩涡的规律性脱落,使得主梁断面发生涡振的机率和涡振振幅都大大减小。

英文摘要：

Steel-concrete composite bridge decks with Π shape are widely used in cable-stayed bridges.Due to the bluff body shape,its aerodynamic properties are not as good as stream-line box decks＇,and the shape should be optimized to enhance its wind-resistant performance.Based on a 300 m span cable-stayed bridge with Π shaped deck,a series of wind tunnel tests of section model are carried out in TJ-1 ABL wind tunnel,Tongji University.The aim of the tests is to select the best aerodynamic bridge deck shape from the three design shapes.After comparing the flutter and vortex-induced vibration aerodynamic performance of the three bridge deck shapes,some valuable conclusions are gotten.The influence of the bridge deck shape to the flutter aerodynamic performance is different with which to the vortex-induced vibration aerodynamic performance in some cases.By comparing with the results in uniform flow,turbulence flow can effectively reduced the risk and amplitude of the vortex-induced vibration due to the fluctuating components.