轻骨料钢管混凝土短柱受火后力学性能的试验研究

摘要

Ceramsite concrete filled steel tube （CCFST） has not only the advantage of lightweight, but also good ductility that the ordinary concrete-filled steel tube structure has. However, study on the performance of CCFST structure after fire is still on the exploration stage. The mechanical behavior of twelve unprotected short columns of CCFST after fire was experimentally investigated. Effects of the parameters, such as the maximum value of fire temperature, fire duration, and slenderness ratio of the specimen and steel proportion on the strength and ductility of CCFST were discussed. The test results show that the CCFST short columns after fire had higher bearing capacity and better ductility, there was no descent segment in the load-displacement curves for most of the specimens after fire, and the bearing load increased again after the descent segment. It was concluded that effect of the maximum value of fire temperature and fire duration on the behavior of CCFST short columns after fire is related to geometrical parameters, and the degree of variation of the maximum value of fire temperature on the bearing capacity of the CCFST short columns increase with the slenderness ratio of the specimen.%钢管陶粒混凝土不仅具有陶粒混凝土轻质的特点，也拥有一般钢管混凝土结构的良好延性，但日的对火灾后钢管陶粒混凝土结构的性能还缺乏研究。通过对3组12根钢管陶粒混凝土短柱受火后力学性能的对比试验研究，讨论小同参数的钢管陶粒混凝土短柱受火后的剩余承载力和破坏形态的变化，重点讨论火灾最高保持温度、最高炉温持续时问、试件长细比、含钢率等参数对钢管陶粒混凝土短柱承载力和延性的影响。试验结果表明，钢管陶卡证混凝土短柱受火后仍然具有较高的承载力和良好的延性，火灾后多数试件的荷载一位移曲线并没有出现下降段，甚至出现承载力部分下降后又重新上升的趋势。火灾持续时间及最高炉温对钢管陶粒混凝土短柱火灾后承载力的影响幅度与试件的几何参数有关，且试件的长细比越大，最高炉温变化对承载力所产牛的影响越显著。