钢管陶粒混凝土柱火灾后轴压性能试验研究

对26根受火后的钢管陶粒混凝土短柱进行了轴压力学性能试验,试件考虑了钢管的几何参数、陶粒混凝土配合比及火灾条件等因素的变化。基于试验结果,分析了轻骨料钢管混凝土短柱受火后的轴压承载力、破坏形态及其他力学性能的变化及相关参数的影响规律。所讨论的主要影响参数包括试验最高炉温、最高炉温持续时间、钢管长细比、混凝土配合比等,并基于对试验数据的分析给出了轻骨料钢管混凝土短柱火灾后轴压承载力的计算公式。结果表明,以轻质材料———陶粒为骨料制成的钢管混凝土短柱受火后仍然具有较高的承载力和良好的延性,而当钢管表面响应温度超过500℃时,试件的轴压承载力出现了明显的下降。所给出的轻骨料钢管混凝土柱火灾后的轴压承载力计算公式可作为该类构件火灾后修复计算的参考依据。

Experimental study of post-fire axial compressive behavior of ceramsite concrete filled steel tubular columns

This study conducted the axial compressive experiment of post-fire mechanical behavior of twenty six ceramist concrete filled steel short columns(CCFSSC) after exposure to fire,considering variation of the factors such as geometrical parameters,proportioning of the ceramist concrete and fire condition.On the basis of the test results,the variations of residual axial compressive bearing capacity,failure form and the other mechanical properties of the CCFSSC after exposure to fire were discussed,and effect of related parameters on the axial compressive characteristics of the short columns was analyzed.Main effect parameters involved here include the maximum value of fire temperatures,duration time of the temperature,slender ratio of the steel tubes and proportioning of the concrete,etc.An expression of the axial compressive bearing capacity of CCFSSC after exposure to fire was put forward based on the experimental results presented.The results show that the short columns still have good post-fire bearing capacity and ductility after exposure to fire,but the post-fire bearing capacity of all the columns decreases significantly when the response temperature of surface of steel tubes is over 500℃.Furthermore,it is noted that the expression used for computation of axial compressive bearing capacity of CCFSSC can be used for giving a reference to post-fire restoration and corresponding computation of the columns after exposure to fire.