Numerical Simulation And Theoretical Analysis Of Seismic Performance Of Self-reset Assembly Piers With External Steel Rod Energy Absorber

The self-reset assembly pier is a new type of bridge pier structure,which divides the pier body into several segments to be prefabricated.It has the advantages of high construction efficiency and strong self-reset ability,It has attracted wide attention in scientific research and engineering practice.The energy dissipation capacity of the self-reset assembly pier itself is poor.The commonly used improvement measures are to set up energy-consuming reinforcement inside the pier column,although the energy dissipation capacity of the pier structure can be effectively improved.However,due to the installation of the reserved hole grouting operation,to some extent reduce the site construction efficiency,after the earthquake,the energy dissipation steel bar buried in the concrete will produce large plastic deformation,which is not conducive to the self-reset of the pier structure after the earthquake,and it is difficult to repair and replace it.Aiming at the problems of self-reset assembly pier,this paper proposes a self-reset assembly pier with steel rod energy dissipation device,and carries out the following research work:(1)Introduces the basic composition of the self-reset prefabricated piers,and summarizes the structure and installation of the external steel bar energy dissipator used;The working mechanism and mechanical properties of self-reset prefabricated pier with external steel bar energy dissipator are analyzed,which provides theoretical basis for the design of this structure.(2)Summarizing the existing seismic design concepts and methods,combining with the bearing capacity analysis of the self-reset bridge pier,the preliminary design method of the self-reset bridge pier with external steel bar energy dissipator based on displacement is presented.(3)The finite element method was used to establish the numerical models of traditional cast-in-place piers,self-reset prefabricated piers with built-in energy dissipating steel bars and self-reset prefabricated piers with external steel bar energy dissipators,and the accuracy of the finite element model calculation results was verified by reference to the test results.Compared with the results of the three models,the results show that the ultimate load and the hysteretic ring envelope area of the selfreset pier with external steel bar energy dissipator are higher than those of the selfreset pier with internal energy dissipator steel bar,and the residual displacement of the self-reset pier with external steel bar energy dissipator is much smaller than that of the traditional cast-in-place pier.(4)To establish a finite element model of 7 external steel rod energy-consuming self-reset assembly piers for pseudo-static analysis,and to explore the effect of the length,diameter and number of energy-consuming steel rods on the seismic performance of the external steel rod energy-consuming self-reset assembly piers.With the shortening of the length,the increase of diameter and the increase of the number of energy-consuming steel rods,the stiffness,energy dissipation capacity and residual displacement of the external steel rod energy-consuming self-reset pier increase;Through the dynamic time history analysis of the external steel rod energyconsuming self-reset pier and the traditional cast-in-place pier,the result shows that the external steel rod energy-consuming self-reset pier exhibits a pier top displacement larger than that of the traditional cast-in-place pier under the actual earthquake action.But there is a smaller residual displacement.