矩形钢箱梁铁路斜拉桥涡振性能及气动控制措施研究

某大跨度矩形钢箱梁铁路斜拉桥存在常遇风速下的涡激振动(VIV).为了抑制涡激振动,采用1∶50节段模型风洞试验,研究了不同气动措施对主梁涡振制振的作用,包括减小栏杆透风率、增设裙板、导流板以及三角形风嘴.试验结果表明,除三角形风嘴能够适当降低主梁的竖弯涡振外,其他气动措施抑制涡振的作用不明显.在此基础上,提出了带平台的...

Vortex-induced vibration performance of a cable-stayed railway bridge with rectangular steel box girder and its aerodynamic countermeasure

The vortex-induced vibration(VIV)of a long span railway cable-stayed bridge with rectangular steel box girder often occurs at frequent wind speeds.In order to suppress the VIV of the girder,the effects of different countermeasures on VIV were studied by wind tunnel tests with a 1∶50 scale section model,including reducing the ventilation rate of the pavement railing and installing apron,baffle and wind fairing.The test results show that the aerodynamic measures presented have no obvious effect on suppressing the VIV of the girder except the triangular wind fairing which can effectively reduce the vertical VIV of the girder.On this basis,the VIV suppression measure of triangular downward wind fairing with platform was proposed,and the test results show that this measure can effectively suppress the VIV of the girder,and its effectiveness was verified by wind tunnel tests with a 1∶25 large-scale section model.Finally,the VIV suppression mechanism of the aerodynamic measure was studied by using computational fluid dynamics(CFD).The calculation results show that the triangular downward wind fairing with platform can simultaneously reduce the vortex size on the upper and lower surfaces of the girder and effectively reduce the unsteady aerodynamic force on the girder.The research results can provide reference to the VIV performance design of the rectangular steel box girder of long span railway cable-stayed bridges.