Research On Practical Method Of Vehicle-bridge Coupling Vibration Of Urban Rail Transit Bridge

Building a country with strong transportation is a major strategic decision made by the 19 th National Congress of the Communist Party of China.Urban rail transit,as an important supporting point for the people’s daily happy life everyday,is naturally the top priority of our government’s investment in infrastructure planning.But with more and more urban rail transit bridges being built,the negative impact of vehicle-bridge coupling vibration has gradually attracted the attention of engineering technicians.In this context,this paper studies the vehicle-bridge coupling vibration practical method of urban rail transit bridges.This method makes the vehicle-bridge coupling vibration analysis more general,and the effect of ship collision on vehicle-bridge coupling vibration of urban rail transit bridge is analyzed by applying this model.The main research work is as follows:(1)A practical analysis method for vehicle-bridge coupling vibration based on the contact theory of FEM is expounded.It is clear that the vehicle-bridge coupling problem is essentially a vehicle-bridge contact problem.By constructing the w(g,λ)= 0 constraint equation on the contact surface,the Lagrangian multiplier method is used to eliminate the iteration by adding parameters,and the calculation of the vehicle-bridge coupling vibration problem is achieved by applying the FEM implicit method.The correctness is verified by two examples;(2)Research on reasonable vehicle mechanical model and vibration stimulus source for vehicle-bridge coupling vibration calculation.By calculating the vehicle-bridge coupling vibration of an As-type urban rail vehicle through a single-span 42 m simplysupported steel box girder bridge,the differences in the mid-span deflection,stress,and interaction forces caused by different vehicle mechanical models and vibration stimulus source parameters are compared;(3)A practical calculation method for vehicle-bridge coupling vibration structural stress of urban rail transit bridges is proposed,in which the bridge adopts a multi-scale finite element model of the entire bridge to calculate the detailed stress time history of the local attention position of the structure.The vibration excitation of the bridge caused by vehicle axle load,track irregularity and vehicle serpentine motion is to generate a command stream file by the transformation formula of moving concentrated load to timevarying equivalent nodal load and programming means,and import it into the bridge finite element model to achieve loading.Use the existing commercial finite element software to calculate the structural stress time history of the vehicle passing through the bridge;(4)Using the Chongqing Qiansimen Jialing River Bridge as the engineering background,a bridge pier and ship finite element model is established to calculate the time-history curve of the impact force of a ship colliding with the bridge pier under different conditions.The force time-history curve of ship hitting bridge pier is loaded as the node time-history load at the impact position of the tower column in the vehicle-bridge coupled vibration model.Considering track irregularities and vehicle serpentine motion,the dynamic responses of vehicles and bridges are calculated,and the influence of ship collision on vehicle-bridge coupling vibration of urban rail transit bridges is analyzed.