火灾后型钢混凝土轴压柱剩余承载力试验

进行了5个火灾后型钢混凝土柱轴心压力作用下的试验,研究长细比、混凝土强度对构件破坏形态和剩余承载能力的影响。试验结果表明,火灾后型钢混凝土轴心受压柱在荷载作用下的破坏形态与常温下基本相同,试件破坏时其内部核心型钢依然完好,不会发生局部屈曲现象。混凝土强度和长细比是影响型钢混凝土轴心受压柱火灾后承载能力的两个重要因素,当长细比相差不太大的情况下,混凝土强度高的试件,其火灾后极限承载力相对较高;在混凝土强度大致相当的情况下,随着长细比的增大,火灾后试件的极限承载力降低。利用YB规程和JGJ规程方法,对所有试件常温下的极限承载力进行了计算,结果表明在该文的试验条件下得到的火灾后型钢混凝土轴心受压柱承载能力的试验值与常温下承载力计算结果的比值在62%~71%之间,经历火灾作用后型钢混凝土轴心受压柱承载能力显著降低,火灾后的剩余承载力水平平均为常温下承载力水平的67%。

EXPERIMENTAL STUDY ON RESIDUAL LOAD BEARING CAPACITY OF SRC COLUMNS UNDER AXIAL FORCE AFTER EXPOSURE TO FIRE

This paper provided five test data pertaining to the residual load bearing capacity of steel reinforced concrete(SRC) columns after exposure to fire.Two parameters,that is,slenderness ratio and concrete strength are mainly taken into consideration.Test results show that the failure pattern of SRC columns under an axial pressure force after exposure to fire is basically the same with that at room temperature.When the specimens are destroyed,the internal core steels are still fine,having no local buckling phenomena.Concrete strength and the slenderness ratio are two important factors that affect the strength of SRC columns under an axial pressure force after exposure to fire.For the specimens of about the same slenderness ratios,the higher concrete strength they are,the higher ultimate bearing capacity they have.In the condition of roughly the same concrete strength,the ultimate bearing capacity of specimens reduces with the increase of the slenderness ratio.The ultimate bearing capacity of all specimens at room temperature is calculated on the method proposed by Chinese regulation YB 9082-2006 and JGJ 138-2001.The compared results of experimental values of SRC columns under an axial pressure after the fire hazard and calculating values of SRC columns under an axial pressure at room temperature show that the bearing capacity of SRC columns under an axial pressure after the fire hazard decreases significantly,only about 67% of that under room temperature.