拉杆约束方钢管超高强混凝土柱的轴压性能及承载力计算OA

To investigate the axial compressive behavior of square tie bar-confined super high-strength concrete-filled steel tubular(STCFT)columns,monotonic axial compression tests were completed on 14 STCFT columns with a concrete compressive strength of 107 MPa.The test variables included the width-to-thickness ratio of the steel tube,the number of tie bar rows along the column height,and the tensile strength of the tie bars.A calculation formula for the axial compressive bearing capacity of STCFT columns was proposed,and this formula can accurately predict the axial compressive bearing capacity of square and rectangular tie bar-confined concrete-filled steel tubular columns.The results indicate that the width-to-thickness ratio of the steel tube has a large influence on the failure mode of the specimens.When the width-to-thickness ratio is 47.8 or 30.1,the buckling location of the steel tube is mainly concentrated between two adjacent rows of tie bars,and the tie bars closer to the local buckling location are more prone to rupture.When the width-to-thickness ratio is decreased to 19.6,the degree of local buckling in the steel tube is re-duced,and the number of ruptured tie bars is also markedly decreased.An increase in the number of tie bar rows can significantly enhance the axial compressive bearing capacity and ductility of STCFT columns.In con-trast,an improvement in the tensile strength of the tie bars has an insignificant effect on the enhancement of its axial compressive bearing capacity and ductility.