Research On Dynamic Response And Anti-collision Device Of Bridge Pier Under Vehicle Impact

Overpasses and other bridges have brought convenience to public transportation,but such bridges bear the risk of vehicle impact,which often occurs.The vehicle impact on bridge piers may not only bring damage to piers but also lead to the dislocation of bridge bearings,and even the falling of beam and other serious consequences.In view of this,it is necessary to study the problem of vehicle impact on bridge piers and carry out anti-collision design for piers.In this paper,the dynamic responses of bridge pier under vehicle impact are analyzed by finite element procedure.A simplified calculation method of equivalent impact force based on energy is proposed.A foam aluminum anti-collision device is designed,and its anti-collision effect is evaluated.The main contents of this paper are as follows:(1)This paper introduces the research and engineering background of vehicle impact on piers.The research methods of vehicle impact on bridge piers,impact force and anti-collision device of bridge piers are summarized.On the basis of a brief literature review,this paper puts forward the shortcomings of the existing work,and points out some urgent problems in the field of vehicle impact on piers.(2)In this paper,ANSYS / LS-DYNA is used to establish a three-dimensional solid finite element model of vehicle impact on the pier,and the dynamic responses are analyzed.The analysis contents include: impact force time history analysis,pier displacement time history analysis,stress at impact surface and pier bottom analysis,energy conversion analysis,etc.The process of vehicle impacting the pier is described quantitatively by dynamic response analysis.The results show that under the impact of vehicles,the impact surface and pier bottom are more likely to be damaged than other parts,and most of the vehicle kinetic energy in the impact process is absorbed by the pier.(3)The influence of vehicle speed and pier section size on impact force is studied by using parameter analysis method.In order to further calculate the equivalent impact force,the existing methods are used to complete the calculation,and a simplified calculation method based on energy is proposed.Then the calculation results of various methods are compared and analyzed.The accuracy and application scope of each method are evaluated.The results show that,among the existing methods,the equivalent displacement method is more suitable for calculating the equivalent static force of the vehicle impacting the pier,and the simplified calculation method based on energy proposed in this paper has certain accuracy.(4)In order to solve the problem of pier anti-collision,a foam aluminum anti-collision device is designed in this paper.In order to verify the effectiveness of the device,the dynamic responses of the pier with anti-collision device under vehicle impact are analyzed.The results show that the aluminum foam anti-collision device can reduce the impact force,reduce the pier displacement,reduce the stress level of the pier,absorb the impact energy,and have a certain protective effect on the pier.Finally,in order to provide reference for the design parameters of the device,a parametric analysis experiment is carried out.The influence of the foam aluminum thickness and the porosity on the performance of the anti-collision device is evaluated.