Study On Seismic Performance Of Resilience Thin-walled Hollow Piers With Cross Reinforcement Energy Dissipation

At present,China’s infrastructure is in a high-speed development stage,thin-walled hollow piers are widely used in large-scale bridge projects in Western China.As a kind of disaster with great influence in nature,the structural damage caused by earthquake often has a huge impact on social economy.In order to reduce the overall failure or even collapse of the bridge structure caused by the post earthquake damage of the bridge pier structure and improve the safety of bridge structure in earthquake,the post earthquake performance recovery design of bridge pier structure has gradually become a research hotspot.The concept of structural seismic design has changed from a single emphasis on seismic safety to a post earthquake performance recovery based on the structure.The resilience pier can dissipate the seismic energy and effectively eliminate or reduce the residual displacement under the earthquake action.It can get rid of the difficulty of repairing or high cost caused by the excessive residual displacement of the traditional cast-in-place concrete pier after the earthquake,and has good social and economic benefits.In this paper,based on the traditional vertical reinforcement energy dissipation member,the cross reinforcement is taken as the resilience bridge pier energy dissipation member,and the finite element numerical model of the resilience thin-walled hollow bridge pier with cross reinforcement energy dissipation is established to study the seismic performance,in order to provide reference for exploring the structural performance of the new resilience thin-walled hollow pier.The following are the relevant research contents:(1)Under the current research situation of resilience piers and thin-walled hollow piers at home and abroad,this paper introduces the concept,basic composition,component design and mechanical properties of resilience piers,and summarizes the common theories and methods of structural design and performance evaluation of resilience thin-walled hollow piers.It provides a theoretical basis for the subsequent research on the seismic performance of the structure.(2)The finite element numerical analysis model of resilience thin-walled hollow pier with cross reinforcement is established,and the quasi-static analysis is carried out under the action of low cycle reciprocating load,and the influence of key parameters on the seismic performance of the pier is analyzed.On this basis,the parameters are optimized and the optimal performance group of the structure is defined.Compared with the resilience thin-walled hollow piers with vertical reinforcement under the same parameters,the effect of cross reinforcement on the seismic performance of resilience thin-walled hollow piers is verified.(3)According to the numerical analysis model of resilience hollow pier with different types of energy dissipation components(cross reinforcement and vertical reinforcement),the dynamic time-history analysis is carried out by selecting the seismic parameters.To evaluate the seismic performance of the two structures under the same earthquake action,identify the weak links of the cross reinforcement structure,and on this basis,put forward targeted optimization suggestions,providing reference for the actual engineering structure design.The results show that the bearing capacity and energy dissipation capacity of the resilience thin-walled hollow pier equipped with cross reinforcement are improved compared with the traditional vertical steel bar resilience pier.Cross-consumed reinforcements are arranged in a cross shape in space.During the movement of the structure,the anchorage part of the foundation and the cross section area are stressed more,which is easy to cause damage and produce smaller residual displacement;the resilience thin-walled hollow pier with cross reinforcement under the same seismic action has the characteristics of large reaction at the bottom of the pier and small displacement at the top of the pier,which meets the requirements of large earthquake fortification and has good seismic performance.Combined with the results of quasi-static comparative analysis,it is shown that the cross reinforcement plays an important role in seismic energy dissipation.