中文摘要：

利用数值模拟程序RCSSCF分析了荷载比、柱计算长度、截面尺寸、荷载偏心率、配筋率和荷载角等参数对ISO834标准升温作用下钢筋砼等肢十字形柱耐火极限的影响规律。针对不同荷载比、柱计算长度、截面尺寸、荷载偏心率和配筋率共1080种工况进行了四周受火时钢筋砼等肢十字形柱的高温反应分析。在此基础上，定量给出了该类构件耐火极限的实用计算方法。研究表明：荷载角对十字形柱耐火极限影响较小；严格控制荷载比是提高十字形柱耐火极限的有效措施。

英文摘要：

The influence of several parameters, such as load ratio, effective column length, section dimensions, load eccentricity ratio, reinforcement ratio and load angle, on the fire resistance of reinforced concrete column with ＋-shaped cross section and exposed to the ISO834 standard fire, is analyzed. 1080 columns with ＋-shaped cross section and subjected to fire on all sides were selected for fire response analysis. Different load ratios, effective column lengths, dimensions of cross section, load eccentricity ratios and reinforcement ratios are considered in the analysis. Based on the simulation results, a practical calculation method for the fire resistance of columns with ＋-shaped cross section and subjected to fire on all sides is given in this paper. Simulation results show that： （a） load angle has little influence on the fire resistance of column with ＋-shaped cross section; and （b） reducing load ratio is an effective measure to improve the fire resistance of column with ＋-shaped cross section.