Quasi-static Test And Numerical Analysis Of Segmental Concrete-filled BFRP Tube

At present,prefabricated bridge piers have been widely used in non-seismic and lowintensity areas,but because of the lack of sufficient understanding of their seismic performance,their application in high-intensity areas of earthquakes has been limited.Previous studies have shown that FRP tube confined concrete columns have higher ultimate bearing capacity and good ductility and energy dissipation capacity under cyclic loading.In this dissertation,three specimens of segmental concrete-filled BFRP tube with diffrent interfacial connecting components and one specimen of integral concrete-filled BFRP tube are designed,and the quasi-static loading is carried out.The general finite element software ABAQUS and its subroutine PQ-fiber are used to establish the finite element model of the specimen,and the whole loading process of the specimen is simulated and analyzed.Based on the test results,numerical calculation and theoretical analysis,the mechanical behavior of the joints of the specimens is studied.The main conclusions are as follows:(1)The experimental results show that the special connecting components designed in this dissertation can effectively transfer the load between adjacent segments.In terms of the peak strength of the specimens under the horizontal cyclic loading,the peak strength of the specimen connected with reinforcement is 81.3% of that of the integral tube,the peak strength of the specimen connected with BFRP bar is 82.9% of that of the integral tube,and the peak strength of the specimen connected with BFRP sheet is 89.4% of that of the integral tube;(2)Compared with the test results,the finite element model established by using beam elements and considering material hysteresis characteristics can well simulate the mechanical behavior of the segmental concrete-filled BFRP tube under the horizontal cyclic loading.This model can be used to analyze the seismic performance of such composite columns;(3)The results of parameter analysis show that the thickness of BFRP tube,the strength of core concrete and the longitudinal reinforcement ratio at the joints are the important indexes that affect the seismic performance of segmental concrete-filled BFRP tube.With the increase of the thickness of BFRP tube,the initial stiffness,peak bearing capacity,ductility and energy consumption capacity of the specimens increase;as the increase of the strength of core concrete,the initial stiffness and peak bearing capacity of the specimens increase,and the ductility and energy dissipation capacity of the specimens decrease;with the increase of the longitudinal reinforcement ratio at the joints,the initial stiffness,peak bearing capacity,ductility and energy consumption capacity of the specimens increase;(4)The horizontal load-bearing capacity and the ultimate deformation capacity of the segmental concrete-filled BFRP tube are analyzed and studied,the calculation and design suggestions are proposed.