高温下混凝土轴压柱的截面极限承载力随机分析

在已有的混凝土和钢筋高温力学性能统计结果基础上,拓展了它们相对高温强度概率模型的温度适用范围;通过在混凝土轴压柱的截面分析中引入2种材料的随机性,探讨了该类柱的截面高温极限承载力的概率特性.研究表明:无论是否考虑材料常温强度的随机性,柱截面高温极限承载力都近似服从正态分布;是否考虑材料常温强度的随机性,对柱截面高温极限承载力均值几乎没有影响,但对其变异系数影响明显;直接选用混凝土和钢筋常温强度以及相对高温强度的均值进行计算,可较好地确定柱截面高温极限承载力的均值.

Random Analyses of the Sectional Load Bearing Capacities of Axially Loaded Reinforced Concrete Columns in Fire

Based on the existing statistical results of concrete and steel bar’s mechanical properties at high temperature,the probabilistic models for concrete and steel bar’s relative strengths at high temperature were extended to a larger thermal range.Considering the randomicity of concrete and steel bar’s strengths in the sectional analysis of axially loaded columns in fire,the statistical characteristics of the columns’ sectional load bearing capacities were studied.The results have shown that:(a) whether the randomicity of concrete and steel bar’s strengths at room temperature are considered or not,the columns’ sectional load bearing capacities in fire follow the normal distribution;(b) the randomicity of concrete and steel bar’s strengths at room temperature has almost no influence on the mean values of the columns’ sectional load bearing capacities in fire,but has significant effect on their variation factors;and(c) the mean values of the columns’ sectional load bearing capacities in fire can be directly determined through calculation by using both the mean values of concrete and steel bar’s strengths at room temperature and the mean values of their relative strengths at high temperature.