Analysis Of Vehicle-bridge Coupling Vibration Of Multi-span Continuous Beam Bridge Under Double-track Rail Transit

The increasingly perfect urban rail transportation brings convenience to urban residents.At the same time,the problem of bridge structure vibration caused by subway trains running on elevated lines was also becoming more and more significant.At present,the simulation analysis of vehicle-bridge coupling mainly focuses on the dynamic response analysis of single-track trains or double-track trains passing bridges.For urban rail transit single-track trains running in different lanes and multi-lane trains,the interaction between long-span bridges and trains Dynamic responses analysis were still relatively small.Taking into account the serious traffic congestion problem in some cities in my country,the number of urban rail transit vehicles had increased,and the possibility of multi-line trains passing through long-span bridges at the same time has increased significantly.For this reason,this article takes a long-span continuous girder bridge for urban rail transit as the research object.First,used the multi-body dynamics calculation software SIMPACK to established the 6-car marshalling model of the subway B-type train;secondly,used the space finite element analysis software ANSYS to established the bridge structure girder model and rail model;finally,imported the bridge and rail model data to SIMPACK A vibration analysis model of the bridge-train-track coupling system was established in the software,and the influencing factors of the coupled vibration of the long-span continuous beam vehicle-bridge of urban rail transit were analyzed.The main research contents were as follows:(1)Used the multi-body dynamics calculation software SIMPACK,the train dynamics model was established according to the basic assumptions and dynamic parameters of the train and vehicle,and its natural vibration characteristics were analyzed.Based on the U.S.orbit spectrum,the German orbit spectrum and the orbit spectrum of the three major trunk lines in China,the trigonometric series method was used to numerically simulate the orbit irregularities to obtain sample values ? ? of different orbit spectra.Combined the train wheel-rail contact relationship established the train-wheel-rail contact model;explain the method of realizing wheel-rail coupling in SIMPACK software.(2)Used the space finite element software ANSYS to establish a grid model of a long-span continuous beam bridge for urban rail transit and analyze its natural vibration characteristics.Through data exchange,the bridge model was imported into SIMPACK software,combined trains and flexible tracks Model,established a bridge-train-track coupling system vibration analysis model.(3)Based on the above-mentioned bridge-train-track coupling system dynamic analysis model,used SIMPACK software,analyze the effect of different train lanes,bridge structure types,train speeds,different track irregularities,rail fastener failures,and double-track trains.The impact of vehicle-bridge coupled vibration responses,and evaluates the safety and stability of train operation and the safety of bridges in accordance with the national railway train and bridge dynamic response evaluation standards.The research results show that: 1)When the train was running in the second lane,the impact on the dynamic response of the vehicle was small.2)Compared with simply supported girder bridges,single-track trains had less impact on the dynamic response of trains and bridges when they run on continuous girder bridges under the same conditions.3)When the train speeds were within the range of 80km/h～160km/h,the dynamic responses index of the train and bridge will change linearly with the speed of the train.4)The American five-level track spectrum had a greater impact on the safety and stability of the train,and the track irregularity had a small impact on the dynamic responses of the bridge.5)When three consecutive fasteners fail,the stability of the train and the dynamic responses of the bridge-track would increase significantly,and the wheel load reduction rate of the train would be affected.6)When driving in two lanes in the second and third lanes,the bridge vibration response was relatively small.