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通过31根高强螺旋箍筋约束高强混凝土方形截面柱的轴心受压试验,对该类型柱的破坏形态、应力-应变关系曲线等进行了研究,分析了箍筋强度、箍筋间距、箍筋形式及截面尺寸对其性能的影响。结果表明:采用高强箍筋约束是防止高强混凝土应力-应变曲线陡然下降的有效措施;箍筋间距较小、强度较高、形式较复杂的约束混凝土试件,其应力-应变曲线的下降段较为平缓,显示出良好的延性性能;体积配箍率对约束混凝土强度和延性提高程度的影响要明显大于箍筋强度,当ρv.fyv相近时,高配箍率低强度箍筋试件的性能要好于低配箍率高强度箍筋试件;约束混凝土达到峰值强度时,高强箍筋并未屈服,其强度的富裕量可保证约束混凝土试件在达到极限破坏状态之前具有良好的延性性能。在该文试验的基础上,结合国内外试验数据,通过回归分析提出了高强箍筋约束高强混凝土峰值强度和极限应变的计算公式。
The axial compressive tests of 31 columns with high strength helical stirrup constraining square columns with high strength concrete columns were carried out to study the failure modes and stress-strain curves of the columns. The influences of the stirrup strength, stirrup spacing, stirrups Form and cross-sectional size of its performance. The results show that the use of high-strength stirrup restraint is an effective measure to prevent the sudden drop of stress-strain curve of high-strength concrete. The smaller the confining stirrup spacing and the higher the strength are, the more complex forms of restrained concrete specimens have lower stress-strain curves The effect of volumetric stirrup ratio on the strength and ductility of restrained concrete is obviously greater than that of stirrup. When ρv.fyv is similar, the performance of stirrup with high stirrup and low stirrup is better than that of stirrup When the confined concrete reaches the peak strength, the high strength stirrups do not yield, and the strength of the confined concrete can ensure that the confined concrete specimens have good ductility before reaching the ultimate failure state. Based on the experimental results and the experimental data at home and abroad, the formulas for calculating the peak strength and ultimate strain of high strength concrete confined by high strength stirrups are proposed by regression analysis.