Experimental Study On Mechanical Behavior Of Prefabricated Core Steel Tube-reinforced Concrete Composite Columns

A new type of prefabricated core steel tube reinforced concrete composite column(called PCSTRC column)was proposed for the rapid development of architectural structure industrialization,which was assembled near the contraflexure point of column to column joint.The PCSTRC columns are composed of two upper and lower columns,the joint is located by the cup of the lower column and the tonon of the upper one and the longitudinal reinforcement is connected by reinforced bar sleeve of the lower column.Such a new assembled joint has simple construction and do not need the lateral support.In order to study the mechanical properties of the PCSTRC columns,this paper has finished the follow research:Two prefabricated core steel tube reinforced concrete(PCSTRC)column,one reinforced concrete(RC)column and one core steel tube reinforced concrete(CSTRC)column were test under monotonic axial loading to investigate the axial mechanism and parameters include core steel ratio and assembly structure on the axial compression performance of specimens.It is indicated that axial compression bearing capacity is 14.6% higher than the RC column and about 10% lower than CSTRC.The PCSTRC show good axial bearing capacity.A refined three-dimensional finite element model of PCSTRC columns under monotonic loading are established by ABAQUS.It is indicated that the numerical simulation technique used in this paper can rationally simulate the experimental process of PCSTRC columns.Based on the experimental verification,the FEM model is used on axail compression performance of PCSTRC columns,enrich and supplement the experimental data.Two prefabricated core steel tube reinforced concrete(PCSTRC)column,one reinforced concrete(RC)column and one core steel tube reinforced concrete(CSTRC)column were test under the cyclic load to investigate the axial compression ration and assembly structure on the seismic behavior of specimens.It is indicated that the increase of axial compression ratio,the horizontal bearing capacity and displacement ductility have been improved.Longitudinal steel connection technology is the key to ensure the seismic behavior of assembly specimens.PCSTRC columns have good seismic behavior,if the quality of stripping ribs with straight thread is ensured.