Study On Seismic Behavior Of Prefabricated Concrete Columns With Steel Section Connections

In view of the main vertical load-bearing component column in the prefabricated building,its joint area is the key point of the whole structure anti lateral force system,which plays an important role in the safety and stability of the structure,and also affects the seismic performance of the structure and restricts the development of the prefabricated building.In order to ensure the effective transmission of load between the assembled columns,the joints should have good strength,rigidity,stability,seismic energy consumption capacity and construction operability.Based on the idea of realizing the pure dry connection of the assembled buildings,this paper proposes a new type of joint form of "steel connection assembled concrete columns".Based on the conceptual design and theoretical calculation analysis of steel section joints,the recommended design parameters of steel section joints with prefabricated concrete columns are given.Based on the quasi-static test of steel-reinforced concrete columns,the seismic performance and stress characteristics of the members under different axial compression ratio levels are studied,and the finite element model which is fully matched with the test piece is established by using ABAQUS finite element software.The results of finite element simulation under the same load condition are consistent with the test results,which verifies the rationality and positive of the finite element model Accuracy.Two steel joint concrete columns are designed and manufactured.The low cycle repeated horizontal load tests are carried out under different axial pressure levels.The seismic performance and failure mode of the columns are studied from the aspects of hysteretic curve,skeleton curve,rigidity degradation,energy dissipation capacity and ductility.The test results show that the concrete columns with steel joints have good seismic performance.This paper analyzes the strain development law of longitudinal reinforcement,stirrup,joint and concrete anchor bar in the connection area of section steel joint and section steel itself,as well as the relative displacement development of the connection area of section steel joint and concrete.The test phenomenon shows that the above-mentioned key stress characteristic parameters do not have significant plastic development and are not earlier than the damage of concrete column itself,which verifies the type of section steel joint Safety and reliability.Using ABAQUS finite element software,a three-dimensional solid nonlinear finite element model of assembled concrete column with steel section connection is established and analyzed.The material properties,boundary conditions and loading system of the model are the same as the actual test conditions.The failure mode,strain distribution and hysteretic curve of the assembled concrete column and joint area are obtained.By comparing with the test results,the rationality of the finite element simulation is verified.The model can be used to further study the influence of other design parameters on the performance of steel section joints.The section steel joint proposed in this paper optimizes the construction technology of assembling concrete column,improves the construction efficiency on site,and can effectively solve the problems such as difficult assembling and positioning,unreliable joint connection,etc.in assembling building connection,which has strong engineering promotion value.