Research On Dynamic Response Of Socket Type Prefabricated Bridge Pier Under Vehicle Impact

In recent years,the application of bridge prefabrication technology in bridge engineering is becoming more and more widespread.Socket-type prefabricated pier has the advantages of short construction period,less on-site operation,and small impact on the surrounding environment.Began to show strong competitiveness in bridge engineering substructures.However,with the increasing traffic volume,there are more and more collision accidents between cars and bridges,ranging from traffic jams for a long time to traffic crashes.Therefore,in order to reduce the damage caused by the impact of the vehicle to the socket-type precast pier and reduce the economic loss,it is necessary to study the dynamic response and damage mechanism of the socket-type precast pier under the vehicle impact.1.According to the engineering application situation and research status of socket prefabricated pier at home and abroad,the model test of vehicle impact of socket prefabricated pier was designed,and the mechanical properties of the grout were tested to obtain the bending strength of the grout,Compressive strength,elastic modulus and stress-strain relationship.2.Through the model test,the dynamic response of the pier acceleration,impact force and steel bar strain time history of the plug-in prefabricated bridge pier specimens with different insertion depths under the impact of the model vehicle with different speeds is obtained.In contrast,the influence of the socket connection form and socket depth on the response of the bridge pier to vehicle collision is obtained.When the model vehicle hits the socket prefabricated pier at a speed of v = 26.67 km / h,the prefabricated pier column of the 0.6D socket pier is pulled out at the socket connection section,0.6D socket depth cannot be applied to socket prefabricated piers.The final failure form of the 1.0D socket depth pier is basically the same as that of the integral type,and it is basically the same as the integral type in terms of acceleration response,concrete strain extreme value,steel bar strain extreme value increase and decrease trend and amplitude In the case where the connection interface is not roughened,the minimum socket depth of the socket connection can be taken as 1.0D.3.Use ANSYS / LS-DYNA software to establish a finite element numerical analysis model,simulate the experimental conditions,and compare the simulation results obtained by the finite element analysis with the test results obtained by the vehicle impact bridge pier model test It is in good agreement with the test results and can effectively reflect the dynamic response of the vehicle impacting the socket prefabricated pier.4.Combining the model test results and the numerical simulation parameters of the test conditions,according to the application of the socket prefabricated pier in actual engineering,the vehicle impact analysis model of the 1.0D socket prefabricated pier is established to study the damage situation of the axle of the socket prefabricated pier.And the relationship between dynamic characteristics such as impact force response and vehicle structure type,vehicle weight,impact speed and axle pressure ratio.Studies have shown that when the vehicle type is a C2500 pickup,the peak impact force is greater than the F800 truck.With the increase of the vehicle mass and speed and the increase of the axial compression ratio of the pier,the peak impact force increases,but it does not increase linearly.The impact of the vehicle speed on the peak impact force is greater than the impact of the vehicle mass.