Experimental Research On CFRP Reinforcement Of Bridge Piers With Precast Segments

The bridge structure is an important part of the transportation network,and the segmental precast pier technology has the advantages of rapid construction and improving the construction quality,which can accelerate the construction of the transportation network,and has become the focus of scholars’ research in recent years.Compared with the cast-in-place pier,the segmental Precast Pier has good self reset ability under seismic load,but its bearing capacity is low,energy consumption is poor,and the bottom section concrete is easy to be damaged or even destroyed,which affects its safe operation.Therefore,it is of great significance to improve the seismic performance of Precast Pier and reduce the damage of concrete in the bottom segment,which plays an important role in promoting the rapid application of CFRP reinforcement technology to Precast Pier reinforcement.Considering the serious damage of the bottom section concrete of the segmental Precast Pier under the seismic load,in order to improve the strength of the bottom section concrete,reduce the damage of the bottom section concrete and explore the effect of CFRP reinforcement,three groups of components are designed for quasi-static test,and combined with ABAQUS finite element software,the numerical simulation of different strengthening methods of the bottom section is carried out to provide reference High pier seismic performance and reduce the damage of the bottom section of concrete.The research work of this paper mainly includes the following aspects:(1)By consulting the literature of scholars at home and abroad,this paper summarizes the application status,research status and related experiments of segmental Precast Pier at home and abroad,summarizes the key points and shortcomings of segmental Precast Pier at present,and then indicates the main purpose and content of this paper.(2)Design of bridge pier test scheme.According to the requirements of the test scheme,three groups of Precast Pier specimens are designed and manufactured.The design parameters of the test piece,the production process,the preparation of the test,the placement of the test loading device,the layout of the measurement system and the test process are described in detail,and the matters needing attention in the test process are summarized.(3)Description of test phenomena and data processing.Pseudo static tests are carried out on pier members under three different working conditions to describe the apparent phenomena of the members in the loading process.The collected data of displacement,load,strain and joint opening are processed to obtain the skeleton curve,residual displacement,cumulative energy consumption,ductility characteristics,stiffness degradation,strain of reinforcement and concrete and joint opening of pier under different working conditions.The seismic performance is analyzed according to the displacement and dislocation.(4)Based on the ABAQUS finite element software,a model of prefabricated segmented bridge piers is established,and the finite element modeling method is briefly described and the model is verified.Secondly,in view of the serious damage to the bottom section concrete,four bottom section reinforcement methods are proposed.Based on ABAQUS,a numerical simulation study under different working conditions was carried out,and the influence of the four strengthening methods on the seismic performance of the bridge pier and the improvement of the concrete damage degree of the bottom section were compared and analyzed.The results show that the CFRP-bonded bridge piers exhibit good seismic performance,have high bearing capacity,strong energy dissipation capacity,and small residual displacement.Secondly,the parameter sensitivity of CFRP is analyzed,and it is found that changing the number of CFRP layers does not significantly improve the seismic performance of the pier.