The Dynamic Response Of Reinforced Concrete Bridge Pier Under Horizontal Impact

With the increasing number of vehicles and traffic,there is a higher possibility for the reinforced concrete(RC)bridge piers to be impacted by vehicles from the horizontal direction.By combining model test and numerical modeling,this paper has made an in-depth study on the dynamic response of RC bridge pier under low speed impact load from horizontal direction,and carried dynamic test and damage analysis for the impacted pier.The main contents of this paper lay in below.(1)This paper sums up the status quo of research of impact on bridge piers,existing research theories and methods,as well as their applications and limitations,and proposes the direction of further research.(2)This paper implements a model test on the basis of similarity theory for bridge pier impacted by vehicle from horizontal direction with scale model of RC bridge pier and thin-wall steel tube buffer simulating the flexible deflection of the vehicle head.The time history curve of impact load to the bridge pier,displacement and steel strain,as well as the deformation of the buffer are obtained,which together reveal the law of dynamic response of bridge pier under horizontal impact load.(3)This paper establishes a numerical model illustrating the relationship between the vehicle and its horizontal impact load to the bridge pier with ANSYS/LS-DYNA,and analyzes the energy transformation and the time history curve of dynamic response of bridge pier under horizontal impact load,based on the technique of finite element analysis.The analysis results have been compared with the results of model test,so as to verify the feasibility and reliability of the finite element numerical model.(4)This paper also establishes a theoretical computational model to calculate the horizontal impact loads of different vehicles,according to the results of model test and numerical simulation.Moreover,this paper has analyzed the influences of the speed,mass and rigidity of impactor on the impact load.Based on mathematical statistics method,a computational formula for the peak of horizontal impact load is proposed,which is compared with domestic and foreign standards.(5)This paper implements a dynamic test for impacted bridge pier and analyzes thefinite element model,in order to reveal the relationship between the rigidity & size of damaged area and the frequency variation of the bridge pier impacted from horizontal direction.The concept of modal integrity and related computational formula are proposed as the basic standard to judge the degree of damage of the bridge pier.