火灾后圆钢管约束钢筋再生混凝土轴压短柱力学性能分析

Mechanical behavior of circular tubed reinforced recycled aggregate concrete stub columns after exposure to fire

利用ABAQUS软件建立了火灾后圆钢管约束钢筋再生混凝土轴压短柱的非线性有限元模型,在确定混凝土和钢材的本构基础上,对其火灾后剩余承载力和轴压刚度进行了数值计算,并与已有相关试验数据进行比对分析。分析了升温时间、截面直径、材料强度、骨料取代率、含钢率和配筋率等参数对火灾后剩余承载力和轴压刚度的影响规律。结果表明:升温时间和截面直径是影响火灾后试件剩余承载力和轴压刚度的主要因素;提出了该类试件火灾后剩余承载力和轴压刚度的简化计算公式,可为工程实际应用提供参考。

To study the residual bearing capacity and axial stiffness of circular tubed reinforced recycled aggregate concrete （CTRAC） stub columns after exposure to fire, a finite element （FE） model was developed with the program ABAQUS, based on the thermal and mechanical properties of materials. The reliability of the FE model was validated by the good agreement between the theoretical results and the experimental data. The residual bearing capacity and axial stiffness of the CTRAC columns were analyzed based on the FE model, and the parameters investigated include fire exposure time, diameter of cross section, material strengths, recycled aggregate replacement percentage, steel ratio and reinforcement ratio. The study reveals that the fire exposure time and diameter of cross section have noticeable influences on the residual capacity and axial stiffness; simplified formulas were proposed for predicting the residual capacity and axial stiffness of CTRAC columns after fire, which may be a reference for this kind of columns used in practical engineering.