钢管钢筋混凝土短柱火灾后剩余承载力试验与有限元分析

Experimental Study and FE Analysis of Residual Bearing Capacity of Reinforced Concrete-filled Steel Tube Short Columns after Exposure to Fire

为研究圆钢管钢筋混凝土轴压短柱火灾后剩余承载力,在标准升降温全过程曲线作用下,进行了在核心混凝土中配置纵向受力钢筋的6根圆钢管钢筋混凝土短柱的明火试验;基于ABAQUS有限元分析软件建立了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,模型分析结果与试验结果吻合较好,并利用该模型对影响圆钢管钢筋混凝土轴压短柱火灾后剩余承载力的主要参数进行分析。试验结果表明:钢管钢筋混凝土短柱受火后仍具有较高的承载力;升温时间和构件的截面尺寸是影响圆钢管钢筋混凝土轴压短柱火灾后剩余承载力的主要因素;基于常用范围内参数提出圆钢管钢筋混凝土短柱火灾后剩余承载力的实用计算式,可为实际工程中该类构件的火灾后加固提供参考。

In this paper,the residual load bearing capacity of reinforced concrete-filled circle steel tube（RCFST）short columns after fire under axial pressure was studied.Six RCFST short columns were tested by heating following the ISO-834 standard fire condition including cooling phase loading to failure after cooling to room temperature.The temperature field model of RCFST short column under heating condition was built by ABAQUS,and the comparison shows that the theoretical analysis results are in good agreement with the former test results.Based on that,the parametric analysis of residual load bearing capacity of post-fire of RCFST short column under axial pressure was studied.The study reveals that the RCFST short columns still have high bearing capacity in post-fire.Heating up time and sectional dimension of the column are the main parameters influencing the fire resistance of RCFST columns.Based on these parameters,simplified calculation formulas of the residual load bearing capacity after fire were put forward,and calculated results by the formulas showed well agreement with theoretical model results.The achievements may give a reference to the repair and reinforcement of practical engineering where RCFST short columns are used.