中文摘要：

为研究高温下钢筋混凝土异形柱的力学性能，结合结构截面在力和温度作用下的非线性增量有限元分析方法和钢筋混凝土柱耐火极限简化分析方法，编制了钢筋混凝土异形柱高温反应的全过程分析程序RCSSCF。程序考虑了轴力的二阶效应，程序的有效性得到了其他学者试验结果的验证。提出混凝土卸载段的映射温度流动途径，以及应变切线模量、温度切线模量和时间切线模量的计算方法。利用该程序对具有相同横截面积的异形柱和方形柱的高温性能进行比较，包括截面温度大于500℃的损伤严重区域占全截面面积的比例和两端固端的异形柱和方形柱在四周受火和不同轴压比下的耐火极限。分析表明：异形柱的耐火性能明显低于方形柱，耐火极限受轴压比影响大；十字形柱的耐火性能比T形柱好，T形柱则又比L形柱好。

英文摘要：

Based on the nonlinear incremental finite combined action of force and temperature and the element simplifi method for reinforced concrete （RC） sections under the ed fire resistance analysis method for RC columns, an analytic code, RCSSCF, is developed for RC columns of specially-shaped （e.g., ＋, T and L-shaped） cross sections subjected to high temperature. The second-order effect of axial force is considered and the reliability of the code is validated by using the test results provided by other researchers. A method of ＂Temperature-Flow Mapping＂ is presented for the concrete when the stress is on the unloading straight line, and a method is provided for computing the strain tangent modulus, the temperature tangent modulus and the time tangent modulus. The performances of columns of different shaped cross sections exposed to fire are analyzed and com the seriously damaged zone where the temperature exceeds 500℃ to the whole cross including the area percentage of section and the fire resistance of columns with different axial load ratios. The studies indicate that： （a） the performance of special-shaped cross section columns performs worse under fire than a square cross section column; （b） the axial load ratio has a significant effect on the fire resistance of the columns of special-shaped cross sections; and （c） the fire resistance of the column of＋ shaped cross section is better than that of the column with T-shaped cross section, and the fire resistance of the column of T-shaped cross section is better than that of the column of L-shaped cross section.