高温下钢筋混凝土异形柱空间框架的试验研究

开展了3榀足尺钢筋混凝土异形柱空间框架在ISO834标准升温过程下的明火试验，考察了荷载水平和梁柱刚度比对框架破坏形态、关键部位变形历程，以及耐火极限的影响。主要的试验结果表明：（1）破坏阶段框架梁呈现出类似悬链索的受力形态；（2）框架节点不同方向水平线位移和转角的大小与该方向相邻框架梁的轴向膨胀量密切相关；（3）总竖向荷载对框架耐火极限影响显著，而梁柱刚度比却对框架耐火极限影响不大。从结构层次进行抗火研究，可以更全面地把握结构及其各组成部分的火灾行为。

Experimental Study on RC Space Frames with Specially-Shaped Columns Subjected to High Temperatures

Three full-scale RC spatial frames with specially-shaped columns were tested following the ISO834 standard heating process, and the influence of loading level and beam-to-column stiffness ratio on failure mode, displacement-time curve and fire endurance of test specimens was investigated. Main test results show that: (a) frame beams behave by similar catenary action at the failure stage; (b) the thermal expansion of frame beams has great impact on the horizontal displacement and rotation of beam-to-column joints; and (c) loading level has significant impact on the fire endurance of the test specimens, while the effect of beam-to-column stiffness ratio on fire resistance of test specimens is limited. The research on fire resistance of total structures is more convenient to assess the fire performance of the structure and its members.