钝体截面铁路混合梁斜拉桥涡振性能研究

Study on Vortex-induced Vibration Performance of Hybrid Girder Railway Cable-stayed Bridge with Blunt Section

新建广州南沙港铁路龙穴南特大桥采用基于快速施工的栓焊结合矩形截面混合梁斜拉桥,钝体截面的结构抗风是设计的难点之一。以龙穴南特大桥工程为背景,利用理论公式、计算流体动力学CFD数值仿真技术和节段模型风洞试验,开展钝体截面铁路混合梁斜拉桥涡振性能研究。结果表明:原设计截面的节段模型风洞试验显示在±5°、±3°和0°均会发生大幅竖弯涡振和扭转涡振,不满足要求,需要采取气动措施加以控制;提出下1/4稳定板+15°抑流板的气动措施,有效地将涡激振动的振幅抑制在允许范围内。

South Longxue Bridge is a hybrid girder cable-stayed bridge on the new Nansha Port Railway in Guangzhou.The bolt and welding combined technology with rectangular section is used in this bridge based on rapid construction technology.Wind resistance of the blunt section is one of the difficulties in design.Based on the project background of South Longxue Bridge,this paper studiedthe vortex vibration performance of railway hybrid girder cable-stayed bridge with blunt section.Multiple research methods were used in this study,such as the derivation of theoretical formula,CFD numerical simulation technology of hydrodynamics and section model wind tunnel test.The results of section model wind tunnel test show that at the angle of±5°,±3°and 0°,both large vertical bending vortex vibration and torsional vortex vibration will occur,which cannot meet the requirements and should be controlled with aerodynamic measures.A new aerodynamic measure was proposed using 1/4 stabilizer plate+15°baffle plate,which can effectively suppress the amplitude of vortex induced vibration within the allowable range.