火灾下轴压钢柱破坏的判断准则分析

介绍了火灾下轴压钢柱的破坏准则。利用数值分析的方法，根据不同的破坏准则计算火灾下轴压钢柱的临界温度。火灾下钢材的力学性能分别参照EC3和CECS选取。通过对临界温度计算结果的对比分析，发现：①2个变形准则给出的结果基本相同，但以变形准则为判断依据往往会高估构件的临界温度；②应用变形准则需具备一定条件，即火灾下构件的破坏形式为整体失稳或截面强度破坏，若构件发生局部屈曲，变形准则不适用；③同一破坏准则下，火灾下钢材性能分别按照EC3和CECS选取，临界温度计算结果相差超过200℃。最后，给出临界温度设计曲线的上、下限，以方便工程应用。

Failure Criteria of Axially Loaded Steel Columns at Elevated Temperature

Failure criteria of axially loaded steel columns under fire are introduced in this paper. Critical temperatures of steel columns are analyzed numerically according to different failure crite- ria. Mechanical properties of steel at elevated temperature are calculated by EC3 and CECS, re- spectively. Comparisons are made among different predicted results according to different failure criteria. The study shows that： （1） two deformation criteria give generally the same results, both overestimate critical temperatures; （2） it is worth to be noticed that the deformation criteria are only applicable under the condition that the global failure occurs;（3） mechanical properties of steel at elevated temperatures have significant influence on critical temperature of axially loaded columns, more than 200 ℃ differences are observed between temperatures predicted by EC3 and CECS. The upper and lower limits of critical temperatures for axially loaded steel columns are provided for convenient use.