钢骨-钢管高强混凝土柱抗火性能试验研究

Experimental research on fire resistance of circular steel tube column filled with steel-reinforced high-strength concrete

钢骨-钢管高强混凝土柱是一种组合柱设计的新模式,通过钢骨-钢管高强混凝土柱与普通钢管高强混凝土柱的对比轴向负荷和抗火试验,研究了钢骨-钢管高强混凝土柱的耐火性能.试验结果表明,在相同的荷载水平下,两种组合柱的轴向变形均呈现三阶段变化规律:初始膨胀变形阶段、材料损伤导致的压缩变形稳定发展阶段和压缩变形急剧增长的破坏阶段;钢骨-钢管高强混凝土柱的压缩变形稳定发展阶段较普通钢管高强混凝土柱长很多,从而使钢骨-钢管高强混凝土柱的耐火极限达到166 min,而钢管高强混凝土柱仅为46 min,由此可见在钢管高强混凝土柱中加入型钢可显著提高柱子的耐火性能.研究成果可为有关钢骨-钢管高强混凝土柱工程抗火设计提供参考.

Circular steel tube filled with steel-reinforced high-strength concrete is a new model of composite column design. The fire resistance of this composite column was investigated experimentally. One circular steel tube column filled with steel-reinforced high-strength concrete and one circular steel tube column filled with high- strength concrete were tested under axial load and fire. The test results show that the axial deformations of both kinds of the composite columns under the same load level have experi- enced three stages variation： the initial expansion deformation stage, the compression deformation gradual growth stage and the damage stage with the dramatic increasing in compression deformation. The second compression stable development stage of the circular steel tube filled with steel-reinforced high-strength concrete is much longer than that of the circular steel tube column filled with high-strength concrete. Thus the fire endurance of the circular steel tube filled with steel-reinforced high-strength con- crete reaches 166 minutes while the fire endurance of the circular steel tube column filled with high-strength concrete only reaches 46 minutes. Thus encasig section steel can remarkably improve the fire endurance of the circular steel tube filled with high- strength concrete. The research results can provide beneficial reference for the fire design of circular steel tube composite columns filled with steel-reinforced concrete.