Study On Seismic Performance Of Prefabricated Core Steel Tube-Reinforced Concrete Composite Columns

Construction industrialization is the development trend of construction industry.As an important part of construction industrialization,prefabricated structure has been greatly developed.In order to realize the industrial production and assembly construction of the core steel tube reinforced concrete(CSTRC)column,this paper combines the assembly joint technology with the core steel tube reinforced concrete column,and puts forward a construction technology of the prefabricated core steel tube reinforced concrete(PCSTRC)column.The PCSTRC column is connected by the tenon formed by the upper column section and the ground beam through the core steel tube and the cup formed by the steel tube sleeve,the reinforcement is connected by a steel sleeve.In order to study the seismic behavior of PCSTRC columns,the following research works were completed:(1)Three full-scale frame columns were fabricated,including one monolithic reinforced concrete(RC)column,one monolithic core steel tube reinforced concrete(CSTRC)column and one prefabricated core steel tube reinforced concrete(PCSTRC)column,and the low cycle cyclic loading test was completed.The test results show that the overall seismic performance of pcstrc column is slightly lower than that of the cast-in-place cstrc column,its ductility coefficient is increased by 10.7%,and its bearing capacity and energy consumption capacity are reduced by 6.4% and 11.0%respectively,but the reduction amplitude is relatively small as a whole,which shows that the assembly structure proposed in this paper is reasonable and feasible.(2)The seismic performance of monolithic CSTRC columns is better than that of monolithic RC columns.Compared with the monolithic RC column,the bearing capacity of the monolithic CSTRC column with the steel ratio of 1.6% of the built-in core steel tube is increased by 23.8%,the total energy consumption is increased by29.4%,and the ductility coefficient is reduced by 4.7%,with a small reduction.The bearing capacity,energy dissipation capacity and ductility coefficient of PCSTRC columns are increased by 15.9%,15.2% and 5.4% respectively.(3)The refined finite element model is established by ABAQUS software,andthe whole loading process of PCSTRC column under low cycle reciprocating load is simulated.The rationality of the model is verified by the comparison of the finite element results and the test results.On this basis,the seismic performance of PCSTRC column is analyzed.The results show that the increase of axial compression ratio and yield strength of steel tube can improve the bearing capacity of the specimen;the increase of longitudinal reinforcement ratio and yield strength of longitudinal reinforcement can significantly improve the bearing capacity and energy consumption of the specimen;with the increase of steel ratio of steel tube,the bearing capacity of the specimen is limited and the energy consumption is obviously increased.