Fire Resistance Analysis of RC Beam Supporting Column Transfer Structure Joints

To provide the basis for the fire prevention design of reinforced concrete beam supporting column transfer structures, according to the structural characteristics, two kinds of full size beam supporting column transfer structure joints are designed. The reinforced concrete beam supporting column transfer structure joints are exposed to fire, and their fire resistance is tested. Based on the test results, using ABAQUS —a finite element analysis software, considering the influence of raising temperature curve, loading ratio, protective layer thickness, additional steel bars, the number of surfaces in fire of a transfer girder, the fire resistance of beam supporting column transfer structure joints is analyzed and the variation of the fire resistance for these beam supporting column transfer structure joints is summarized. The analysis results show that heating curve and maximum temperature have a significant influence on fire resistance; the fire resistance limit of joint units with load ratio of 0.6 is smaller than that of joint units with load ratio of 0.4; the thickness of the protective layer of the longitudinal tensile reinforcement of the joint unit differs, while the fire resistance limit ranges from large to small for protective layer thickness of 50 mm, 40 mm, and 25 mm, respectively; hanging steel bars in the transfer girder can improve the fire resistance and help avoid sudden damage. The more surfaces of the transfer girder are in fire, the shorter is the fire resistance. Under the same loading ratio, two kinds of beam supporting column transfer structure joints have different damage characteristics and fire resistance.