Dynamic Response Analysis Of Overpass Bridge Under Vehicle Impact And The Study On Its Anti-collision Device

As the urban traffic network becomes more and more dense,a large number of bridges have been built to solve the problem of crossing different forms of traffic and meet the needs of pedestrians.At the same time,the overpasses are hit by the vehicle from time to time,it causes the death of the person and the damage of the vehicle and the bridge.In order to study the dynamic response of a vehicle hitting a span bridge and its anti-collision device,the finite element method was used to carry out on a span bridge,and a steel-FRP anti-collision device was designed to optimize the design of the span bridge.This paper content specifically as follows:In the first place,in this paper,the accident of bridge and car at home and abroad in the field of axle collision generalized the research status,this paper uses the basic theory of finite element and contact algorithm which were expounded.To study the bridge and the steel-FRP anti-collision device,it chose the appropriate material which accords to the test data provided,and then it achieved the composite material constitutive model of the concrete,including the steel bar,the steel jacket box and the FRP.Then,In order to study the dynamic response of overpass bridge under the impact of vehicles,an overpass bridge was taken as the research object,and finite element software was used to establish the truck-pier collision model for analysis by considering the dead weight of the superstructure.Numerical simulation was carried out with different truck speed,collision Angle and mass impact on bridge piers.The time history of impact force,displacement of pier top,the moment of pier’s bottom and the acceleration of truck are compared and analyzed,and the characteristics of damage and the evolution of pier are studied.The results show that the impact force and pier displacement are affected by velocity,angle and mass.In the course of truck-bridge collision,the pier damage is obvious and it mainly occurs the bending failure.Finally,according to the dynamic response result of the bridge pier hit by the vehicle,a steel-FRP anti-collision device was designed,and the response surface method based on BBD test was used to optimize the anti-collision device,and the optimal structure combination of anti-collision device was obtained.The results show that the optimal size combination can maximize the design efficiency,and the steel-FRP anti-collision device has good safety,reliability and economy,which is convenient for the promotion and application in practical engineering.