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为研究方钢管钢筋混凝土轴压短柱火灾后的剩余承载力,设计并制作18根在核心混凝土中配置纵向受力钢筋的方钢管钢筋混凝土短柱进行明火试验和承载力试验,观察试件经历火灾后的破坏形态,获取柱的极限承载力等指标。在ISO 834标准升降温曲线作用下,基于ABAQUS有限元软件建立方钢管钢筋混凝土轴压短柱温度场和火灾后力学场分析模型,分析结果得到试验结果的验证,在此基础上,利用该模型对影响方钢管钢筋混凝土轴压短柱火灾后剩余承载力的参数进行了分析。试验结果表明:受火后的方钢管钢筋混凝土短柱承载力有一定程度折减,但仍具有较高的承载能力;配置纵向钢筋对核心混凝土起到更好地约束作用,配筋率的增大对于受火后试件极限承载力的提高作用明显;影响方钢管钢筋混凝土轴压短柱火灾后剩余承载力的主要因素是升温时间和构件截面尺寸;在常用参数范围内,回归方钢管钢筋混凝土短柱火灾后剩余承载力实用计算式。
In order to study the residual bearing capacity of concrete-filled square steel tubular stub columns after fire, 18 concrete-filled square steel tubular short columns with longitudinally loaded steel bars in core concrete were designed and fabricated for open fire test and bearing capacity test. After the fire damage morphology, access to the ultimate bearing capacity and other indicators. Under the action of ISO 834 standard temperature rising and cooling curve, the temperature field of square steel tubular short-stub columns and the mechanical field analysis model after fire were established based on ABAQUS finite element software. The analysis results were verified by the experimental results. Based on this, The parameters that affect the residual bearing capacity of square steel tubular short columns after fire are analyzed. The test results show that the bearing capacity of reinforced concrete short columns of square steel tube after fire is reduced to a certain extent, but still has a high carrying capacity; the longitudinal reinforcement is better restrained to the core concrete and the reinforcement ratio is increased Large for the ultimate bearing capacity of the specimen after the fire to enhance the role of obvious; the impact of square steel reinforced concrete axial compression column residual stress after the main factor is the heating time and the cross-sectional dimensions of components; common parameters in the range of regression square steel pipe reinforcement Practical calculation formula of residual bearing capacity of concrete short column after fire.