圆钢管混凝土柱全过程火灾作用后剩余承载力实用计算方法

Simplified Method for Residual Strength of Concrete-Filled After Exposure to Fire

利用程序NFEACFST对火灾后圆钢管混凝土柱剩余承载力进行了参数分析,选用的参数包括升温时间比、火灾荷载比、截面边长、截面含钢率、材料强度、长细比等。得出结论:升温时间比、火灾荷载比、截面边长以及长细比是影响火灾全过程作用后圆钢管混凝土柱剩余承载力的主要影响参数。为方便工程应用,提供了简化计算公式,利用该公式计算了大量算例,并与理论计算结果进行对比,二者吻合较好。简化公式概念清楚,形式简单,符合实用原则。

Based on the Program NFEACFST, influences of parameters on residual strength of concrete-filled steel tube columns were analyzed. The parameters included temperature ascending time ratio, fire load ratio, cross-section dimension, steel ratio, material strength and slenderness ratio, etc. It was found that, in general, ascending time ratio, fire load ratio, cross-section dimension and slenderness ratio have a significant influence on residual strength.Asimplified calculation formula for residual strength after exposure to ISO-834 standard fire was suggested based on systematic parameter analysis reslts.Validities wereprovided by the comparisons between the results using simplified and theoretical method.The formula was simple and clear,and could providerefe rences for application of this kind of columns in engineeringpractice.