高温下钢筋混凝土异形柱的试验研究

Experimental study on reinforced concrete columns with special shaped cross section subjected to high temperature

进行了11根钢筋混凝土异形柱和1根钢筋混凝土方形柱在ISO834标准升温过程下的明火试验,分析了轴压比和受火方式对高温下不同截面形状的钢筋混凝土柱的破坏形态、轴向变形,以及耐火极限等的影响。试验结果表明:(1)钢筋混凝土异形柱的耐火性能明显低于方形柱。(2)轴压比对异形柱的耐火极限影响较大。(3)一般而言,十字形柱的耐火性能比T形柱好,T形柱比L形柱好;但当轴压比较大(例如0.55)时,T形柱的耐火性能有可能好于十字形柱。最后,利用三种高温下钢筋混凝土异形柱的数值分析模型对12根试验柱的耐火极限进行了计算,比较了不同模型的模拟效果。

Eleven reinforced concrete （RC） columns with special shaped cross section and one RC column with square cross section were experimentally investigated in fire following ISO854 standard heating process. The effects of axial load ratio and fire exposure case on failure mode, axial deformation and fire resistance of RC columns with different shaped cross sections were analyzed. The experimental results show that： （ 1 ） RC column with special shaped cross section exhibits worse fire-resistance performance than RC column with square cross section. （2） axial load ratio has significant effect on fire resistance of RC column with special shaped cross section. （3） generally, the fire resistance of column with ＋-shaped cross section is better than that of the column with T-shaped cross section, and the fire resistance of column with T-shaped cross section is better than that of the column with L-shaped cross section;but the fire resistance of column with T-shaped cross section is possibly better than that of the column with ＋-shaped cross section in case that axial load ratio is bigger, for example 0.55. At last, the fire resistance of these twelve columns was calculated by using three kinds of numerical model proposed by the authors for RC columns with special-shaped cross section, and the numerical results were compared with the test data.