大跨度钢-混结合梁悬索桥涡激振动控制指标体系研究

Study on Controlling Index System for Vortex-Induced Vibrations of Long-Span Suspension Bridge with Steel-Concrete Composite Stiffening Girder

为保证已建桥梁发生涡激振动后桥梁结构的安全以及桥上行车和行人安全,提出综合考虑人员舒适性、结构受力和停车线形三方面的大跨度钢-混结合梁悬索桥涡激振动控制指标体系。该体系包含9项指标,分别为驾乘人员舒适度、驾乘人员晕动症、行人舒适度(狄克曼指标)、加劲梁强度、加劲梁应力、加劲梁挠度、桥面纵坡、竖曲线半径和停车视距。以武汉鹦鹉洲长江大桥为背景,分别计算了“限速”和“封桥”2个交通管制措施下9项指标对应的涡激振动振幅限值。在此基础上,将9项指标对应的涡激振动振幅限值的最小值作为涡激振动限值建议取值。结果表明:当该桥发生低阶竖弯涡激振动(VS1、VAS1)时,涡激振动的控制因素为加劲梁挠度指标;当大桥发生VAS2模态的竖弯涡激振动时,涡激振动由驾乘人员晕动症指标和行人舒适度指标共同控制;当大桥发生高阶竖弯涡激振动(VAS3、VAS4)时,涡激振动由行人舒适度指标控制。涡激振动控制指标体系及限值标准的计算框架可适用于不同桥型涡激振动限值的计算。

The long-span suspension bridges are prone to vortex-induced vibrations(VIVs)at service stage.To ensure the safety of existing bridge structures as well as vehicle and passengers travelling safety in the VIVs events,a VIVs controlling index system that takes into account the human comfort,load bearing behaviors of the structure and driving alignment for the long-span suspension bridge with steel-concrete composite stiffening girder is presented.The system incorporates nine indexes,including the driver comfort,motion sickness,passenger comfort(Dieckmann index),as well as bending capacity,stresses,deflection,longitudinal slope and radius of vertical curve of stiffening girder,and stopping sight distance.In the Yingwuzhou Changjiang River Bridge in Wuhan,the limits of VIVs corresponding to the nine indexes were calculated,considering the two traffic control conditions of speed limitation and bridge closure,based on which,the minimum VIVs values were taken as the recommended values.It is shown that the deflection of stiffening girder is a control index in the events of lower-mode vertical vibrations(VS1 and VAS1),while motion sickness and passenger comfort will take charge in the case of VAS2 modes,and the passenger comfort is also an important control index in the cases of higher-mode vertical VIVs(VAS3 and VAS4).The VIVs control index system and the VIV limits computing framework are applicable to the calculations of VIV limits of different bridge types.