( 3 ) the ultimate load bearing capacity of cross section of reinforced concrete columns exposed to fire is calculated through a program which is compiled in this dissertation , and the effects of different parameters such as dimensions of cross section , concrete cover , reinforcement ratio and compressive strength of concrete on the ultimate load bearing capacity are analyzed ( 3 )编制程序对四面受火钢筋混凝土柱的截面极限承载力进行了理论分析,得到了截面尺寸、保护层厚度、纵筋配筋率及混凝土强度等级等对受火柱截面极限承载力的影响规律。