方钢管约束钢筋高强混凝土超短柱抗震性能试验研究

Seismic behavior of ultra short columns of square tubed high strength reinforced concrete

本文进行3个剪跨比为1.5的方钢管约束钢筋高强混凝土超短柱和1个钢筋混凝土对比试件的试验研究,试验中的主要参数为轴压比(0.35,0.45和0.55)。试验结果表明,由于钢管对核心高强混凝土的约束作用和钢管的抗剪作用,方钢管约束钢筋混凝土超短柱的抗剪承载力、延性、变形能力和耗能性能明显高于钢筋混凝土超短柱。轴压为0.35的方钢管约束钢筋混凝土超短柱的破坏模式为弯曲破坏,而轴压比为0.45和0.55的方钢管约束钢筋混凝土超短柱的破坏模式为剪切破坏。随轴压比的提高,方钢管约束钢筋混凝土超短柱的抗剪承载力提高,但延性系数和极限变形能力降低。对钢管的弹塑性应力分析结果表明,水平荷载施加过程中,发生弯曲破坏试件的钢管不屈服,而发生剪切破坏试件的钢管可能在下降段屈服。根据试验结果和钢管应力分析结果建立方钢管约束钢筋混凝土柱的抗剪承载力公式,提出设计建议,可为工程实践提供参考。

The seismic behavior of square tubed high strength RC（STRC） ultra short columns was studied by testing three STRC columns and one common RC column under combined axial constant compression and lateral cyclic load,with the test parameter being the axial load ratio（0.35,0.45 and 0.55）.The test results indicated that the STRC ultra short column exhibited much higher shear strength,ductility,deformation ability and energy dissipation ability than common RC columns,due to the fact that the steel tube confined the high strength concrete effectively and the web of the tube resisted the lateral shear force.The failure mode of the column with the axial load ratio of 0.35 was flexure failure,while the failure mode of the two columns with the axial load ratios of 0.45 and 0.55 was shear failure.The shear strength increased as the axial load ratio of the columns increased for STRC ultra short columns,while the ductility and ultimate deformation ability decreased as the axial load ratio of the columns increased.The results from elastic-plastic analysis of the steel tube indicated that,during the lateral loading process,the steel tube did not yield for the STRC columns with flexural failure and the steel tube could possibly yield after the peak load for the STRC columns with shear failure.A design equation for calculating the shear strength of STRC columns and design advices were proposed based on the test and analysis results.