Seismic Performance Research On Outer-wrapped High-strength Concrete Composite Columns Of H-beam

Steel Reinforced High-strength Concrete(SRHC)composite structure is more and more popular among high-rise structural designers because of its pure steel and ordinary concrete properties.SRHC has the characteristics of high bearing capacity and high strength,which can give full play to the important mechanical properties of steel,and has a good development prospect.At present,the seismic performance of columns under uniaxial horizontal earthquake is very mature in China,but it under biaxial horizontal earthquake is still in need of further study.In this paper,four high-strength concrete columns were simulated by ABAQUS.the purpose of the simulation is to verify the ABAQUS 's ability to simulate the high-strength concrete columns under low-cycle cyclic loading.At the same time,the ABAQUS was used to verify the correctness of the experimental results under uniaxial low-cycle cyclic loading.Based on the results,the ABAQUS was used to study the seismic performance of SRHC columns under biaxial low-cycle cyclic loading.The effects of six different loading paths,stirrup ratio,displacement amplitude cycle times and variable axial force on the seismic behavior of composite columns are analyzed by ABAQUS.Through the study of the effect of load path on the seismic performance of columns,the follow conclusions are drawn: due to the existence of biaxial coupling in the members,the seismic performance under six biaxial loading paths is lower than that under uniaxial loading,among which the loading path with the lowest bearing capacity(45 degrees of x-axis and y-axis)is the weakest in the seismic resistance,The results show that the loading path is an important factor affecting the seismic performance.Under the loading path of the loading path with the lowest bearing capacity,considering the influence of four different stirrup ratios of 0.889 %,1.123 %,1.497 % and 1.925 % on the seismic performance of the column,the optimal stirrup ratio is 1.123 %,which shows that the appropriate stirrup ratio can increase the seismic performance of the column under biaxial loading.Under the loading path with the stirrup ratio of 1.123 % and the loading path with the lowest bearing capacity,the effects of different displacement cycle times on the seismic performance of composite columns were studied,and the results showed that the displacement amplitude cycle times had no significant effect on the seismic performance of single-axis and double-axis columns.From the point of view of damage degree,the maximum damage degree was three times.Under the loading path with the stirrup ratio of 1.123 %,the number of displacement cycles and the loading path as the lowest bearing capacity,the effects of five different axial force loading modes on the seismic performance of composite columns were studied.the results show that the axial force loading modes with different axial compression ratios in thepositive and negative loading directions have greater influence on the seismic performance of composite columns than the axial force loading modes with the same axial compression ratio.