Wind-Vehicle-Bridge Coupled Vibration Of Long-Span Steel Truss Cable-Stayed Bridge Under Vortex-Induced Vibration

Long-span bridges are mainly built in valleys,rivers or straits,which are influenced by natural wind for a long time and are more likely to produce vortex-induced vibration.In order to ensure the safe operation of long-span bridges under normal service conditions,it is necessary to study the coupled dynamic response of wind-vehicle-bridge under vortexinduced vibration,and to study the vortex-induced vibration amplitude limit of long-span bridges based on train running performance.Based on the Modaomen Bridge of Shenzhen-Maoming Railway,the wind-vehiclebridge coupled vibration of a long-span steel truss cable-stayed bridge under vortex-induced vibration was studied systematically in this thesis.The research contents and main conclusions are as follows:(1)Based on the principle that the total potential energy of elastic system dynamics is constant,the finite element model of long-span bridge was established.Based on this model,the wind speeds of the first-order vertical bending and the second-order vertical bending vortex vibration that may occur in the main girder were determined as 16m/s and 23m/s according to the relevant specifications.The possible first-order and second-order torsional vortex-induced wind speeds were 26m/s and 3 1m/s.(2)Under the condition of no vortex-induced vibration of the bridge,the wind-vehicle-bridge coupled vibration simulation of the bridge was carried out,and the average wind speed-train speed threshold of the bridge deck satisfying the train running performance was obtained.The results show that when the average wind speed of the bridge deck is 16m/s,23m/s,26m/s and 31m/s,the allowable speed of the train is 250km/h,180km/h,140km/h and prohibited.It can be concluded that the vortex-induced vibration of the main girder may occur in the first-order vertical bending,second-order vertical bending and first-order torsion within the allowable wind speed range of the bridge.(3)In the vortex-induced vibration state of the bridge,this paper superimposed the track static irregularity caused by the vortex-induced vibration of the bridge and the track dynamic irregularity,and studied the wind-vehicle-bridge coupled dynamic response under the vortex-induced vibration state.The results show that vortex-induced vibration will significantly affect the dynamic response of trains and bridges,which is closely related to the amplitude and phase angle changes of vortex vibration.The vertical bending vortex vibration mainly affects the vertical vibration of the bridge,the wheel load reduction rate and vertical acceleration of the train;the torsional vortex vibration mainly affects the transverse and vertical vibration of the bridge,the derailment coefficient,the transverse force,the transverse acceleration of the train.(4)According to the above calculation results,the vortex vibration amplitude limit of the bridge satisfying the train running performance was obtained,and the calculation results showed that the limit was stricter than the specified limit of the highway specification.In this paper,the empirical formula of vortex vibration amplitude limit of railway bridge was derived based on the train vertical acceleration limit,which was consistent with the simulation results,and would provide a reference for the formulation of railway specifications in the future.90 Figures,45 tables and 114 references are included in this thesis.