Experimental investigation on axial compression performance of spiral reinforcement ocean concrete-filled stainless steel tube short columns
In order to study the axial compression performance of spiral reinforcement ocean concrete-filled stainless steel tube short columns,the diameter and spacing of spiral reinforcements,the diameter and number of longitudinal reinforcements and the reinforcement ratio of spiral reinforcement to longitudinal reinforcement were taken as varying parameters,and 17 groups of 51 axial compression short columns were designed for static loading tests.The mechanical failure process and the morphology of short columns were observed,and the axial load-displacement curves and the strain curves of each steel were obtained.Based on the test data,the influences of varying parameters on the bearing capacity,axial ductility,energy dissipation capacity and damage development of this kind of short columns were analyzed.The results show that the failure modes of short columns are local buckling and wrinkle of stainless steel tube and oblique shear failure of concrete.Configuring spiral and longitudinal reinforcements can improve the bearing capacity,axial ductility and energy dissipation capacity of the columns by 14.95%,73.25%,19.69%,respectively,and inhibit the damage development of the components.With the increase of spiral reinforcement spacing(increase of diameter),the bearing capacity,ductility and energy dissipation of the components show a decreasing trend.With the increase of longitudinal reinforcement diameter(decrease of number of bars),the bearing capacity decreases first and then increases,the ductility increases first and then decreases,and the energy dissipation decreases.It is suggested that the optimal cross-sectional reinforcement ratio of spiral reinforcement to longitudinal reinforcement be 0.875.Finally,the calculation formula of axial compression bearing capacity of this kind of short columns was proposed,and the calculated values are in good agreement with the experimental values.