受火钢筋混凝土柱截面极限承载力研究

Research on ultimate load capacity of cross section of reinforced concrete columns exposing to fire

用差分分析法对四面受火钢筋混凝土矩形柱截面温度场进行了分析,并用有限元方法计算了受火后一定温度场下柱截面极限承载力,与试验结果对比吻合较好。在此基础上,对受火柱截面极限承载力的各个影响因素进行了分析,结果表明:增大柱的截面尺寸和纵筋配筋率有利于柱截面极限承载力,以及柱的抗火性能的提高;增加保护层厚度也有利于提高柱截面的极限承载力,但是当保护层厚度增加到一定的程度以后,柱截面的极限弯矩就无法提高,因而只能在一定范围内提高柱的抗弯能力。

By using finite difference method, authors calculated the temperature of reinforced concrete columns with rectangular cross section. The ultimate load capacity of columns section with a certain temperature field distribution was also calculated by finite element method. The results were in good agreement with the test data. The effects of different parameters such as cross section size, concrete cover, arrangement of reinforced steel bars, compressive strength of concrete on the ultimate capacity of the rectangular cross section were analyzed. It is concluded that the increase of dimensions, reinforced ratio and concrete cover has a positive effect on columns exposing to fire. Furthermore, the increase of concrete cover is limited in increasing the ultimate bending moment capacity of columns.