标准火灾作用下钢管混凝土短柱落锤动态冲击试验研究

采用落锤冲击实验机进行ISO-834标准火灾作用下钢管混凝土短柱抗冲击性能试验研究,考察受火时间、冲击速度、冲击能量和含钢率对其抗冲击性能的影响。试验量测钢管表面温度、冲击力与压缩变形时程曲线。试验结果表明,受火时间、冲击速度、冲击能量和含钢率均对高温下钢管混凝土的动态力学性能有影响;受火时间对冲击极限承载力和残余变形的影响最为显著,其余参数对冲击承载力影响不大,而试件的残余变形随着受火时间和冲击能量的增大而增大,随着含钢率的增大而减小。常温和火灾下钢管混凝土在冲击荷载作用下产生显著的压缩变形,遭受不同程度的破坏,但仍能够保持很好的截面完整性,说明钢管混凝土在火灾(高温)下具有良好的抗冲击能力,适用于有火灾(高温)抗冲击、抗倒塌设计需求的结构。

Impact behavior of concrete-filled steel tubular stub columns under ISO-834 standard fire

Drop weight setup was employed to experimentally study the behavior of concrete-filled steel tube(CFT) subjected to ISO-834 standard fire.The influences of fire duration time,impact velocity,impact energy and steel ratio on the impact resistance of CFT exposed to fire were discussed.The temperature histories of steel tube surface were measured and the force and compressive deformation histories of the specimens were recorded.The test results showed that fire duration time,impact velocity,impact energy and steel ratio significantly affected the impact behavior of CFT columns under fire,with the fire duration time being the most sensitive.However,the influence of other parameters on the ultimate impact strengths of the hot CFT columns was not significant.The residual deformations increased with the increase of fire duration time and impact energy,but decreased with the increase of steel ratio.Although the CFT specimens at room temperature or under fire suffered remarkable compressive deformations,the composite columns still remained good integrity.The test results showed that CFT under fire has an excellent impact resistance,thus is suitable to resist impact loads and collapse-induced dynamic loads.