Experimental Research On Seismic Behavior Of 600MPa RC Cross-shaped Columns

600MPa reinforcement is a new kind reinforcement with high strength,good ductility,easy construction and other advantages.It is in line with sustainable development and green building materials requirements.When under the strong earthquake,the special-shaped column structure was seriously damaged and the bearing capacity was weak.The wide application of special-shaped column structure is limited.The application of 600 MPa reinforcement in the special-shaped column structure not only can improve the seismic performance of the special-shaped column,but also provide the basis for the application of the 600 MPa reinforcement in the special-shaped column structure and the revision of the relevant specification.In this paper,the low cyclic loading test of the cross-section column with 600 MPa grade steel bars was carried out.The experiment phenomena,the strain curves of the longitudinal and stirrups,the bearing capacity,the hysteretic curve,the skeleton curve,the stiffness degradation and the energy dissipation capacity were analyzed.The effects of stirrup ratio and axial compression ratio on the seismic behavior of 600 MPa reinforced concrete cross-shaped columns were studied.The experiment results showed that the failure modes for all the specimens were flexural failure.The longitudinal reinforcement at the end of the web of each specimen was likely to reach its tension yield strength and compression yield strength.When 600 MPa grade steel bar as a longitudinal reinforcement,it has a better influence.The stirrups were in tension state.The stirrup at the end of the web was readily to reach its tension yield strength.When 600 MPa grade steel bar as stirrup reinforcement,it can reserve strong safety.The hysteretic curve of each specimen was full and the symmetry was good.The cross section column with 600 MPa grade steel bar has high bearing capacity and sufficient energy dissipation capacity,and the seismic performance of each specimen was favorable.With the increase of stirrup ratio,the peak load is increased,the displacement ductility coefficient and the deformation capacity are enhanced.With the increase of axial compression ratio,the peak load and the initial rigidity of the specimen is increased,the energy consumption of the specimen is improved while the rigidity degradation is accelerated.When the reinforcement strength increase,the ultimate bearing capacity and the plastic deformation capacity are increased while its energy consumption capacity is reduced.The finite element simulation of the test was carried out by ABAQUS software.The calculated results were in good agreement with the experimental results.On the basis,the influence of reinforcement strength and longitudinal reinforcement ratio on the seismic performance of 600 MPa reinforced concrete cross column was further analyzed.The results show that with the increase of the strength of the steel,the peak load of the specimen is increased,the plastic deformation capacity is enhanced and the seismic performance is improved.With the increase of the reinforcement ratio,the hysteretic loop of the specimen is fuller and the energy dissipation capacity is enhanced while the stiffness degradation is accelerated.