钢管再生混凝土柱耐火性能研究

Research on fire resistance of recycled concrete filled steel tubular columns

为研究钢管再生混凝土柱耐火性能,进行了包括1个实心和2个空心率不同的截面在内的3根足尺钢管再生混凝土柱耐火试验,并进行了相同截面尺寸的3根足尺钢管混凝土的对照试验。试验结果表明:钢管再生混凝土柱的耐火极限普遍要优于钢管普通混凝土柱的耐火极限;通过ABAQUS模拟耐火试验,对比模拟和试验中各试件轴向位移随时间的变化曲线,验证有限元分析结果的正确性。考虑钢管对再生混凝土套箍作用的折减,基于等效面积的原则,推导了钢管再生混凝土柱常温轴压承载力计算式,利用试验数据对计算式进行了验证,两者比值的平均值为0.923,方差为0.126,计算结果与试验结果吻合良好。基于本课题组已有的钢管和再生混凝土的平均温度场,推导钢管再生混凝土柱高温轴压承载力计算式,利用试验数据对计算式进行了验证,验证了计算式的合理性。

The fire resistance test of recycled concrete filled steel tubular( RCFST) columns was carried out. The specimens included one solid and two different hollow sections with recycled concrete,and another group of tests included three same size specimens with concrete. The result of test indicates that the fire resistant performance of recycled concrete filled steel tubular columns is better than that of normal concrete filled steel tubular columns. The ABAQUS simulation was adopted to simulate the fire resistance test and verified by the comparison between the simulation and test results of the axial deformation. Considering the confining effect is reduced for recycled concrete,the principle of equivalent area was used to deduce the formula of axial bearing capacity for RCFST at the room temperature. The formula was verified through test data. The average value and variance of specific value between them were 0. 923 and 0. 126,respectively which proved the formula was reasonable. Based on the formulas of the average temperature of both steel and recycled concrete that were established by the authors,the formula of axial bearing capacity for RCFST columns at high temperature was deduced. The test result indicates that the formula under standard fire conditions is accurate.