【摘要】 为了深入研究排气孔数量对方钢管混凝土耐火性能的影响,以排气孔数量、轴压比和含钢率为试验参数进行了7个方钢管混凝土短柱耐火性能试验。研究结果表明:排气孔数量会影响试件的鼓曲位置;排气孔数量越多,方钢管混凝土柱耐火极限越低,轴向变形(Δ)-升温时间(t)曲线的后期压缩变形速率越快;轴压比越大,方钢管混凝土柱的耐火极限越低,轴向变形(Δ)-升温时间(t)曲线的膨胀阶段越不明显;含钢率越高,方钢管混凝土柱耐火极限越低,对轴向变形(Δ)-升温时间(t)曲线的影响不大。从高温下钢管混凝土的损伤机理方面解释排气孔数量对方钢管混凝土耐火性能产生影响的原因。研究成果可为该类结构进行防火设计时提供参考。更多还原

【Abstract】 In order to investigate the influence of vent hole numbers on fire resistance of square concrete-filled steel tubular(CFT) columns, the tests of seven square CFT columns subjected to axial loads under high temperature were conducted. The influence of axial load level, number of exhaust vent and steel ratio on exposure time-axial deformation curves and fire resistance time of the square CFT column were studied. The test results show that vent holes have influence on the local buckling position of specimens. As the number of vent holes increased, the fire resistance of the square CFT column reduced as well as the rate of compressive deformation of axial deformation-exposure time curves became faster. As the value of axial load level increased, the fire resistance of the square CFT column reduced, yet the creep phase of exposure time-axial deformation curves became unobvious. As the value of steel ratio increased, the fire resistance time of the square CFT column reduced. The damage mechanism of concrete under high temperature was obtained to study the number of vent holes which have influence on fire resistance of square CFT. The achievements in this paper could afford a design approach for such typed structures.更多还原