Predictability of buckling temperature of axially loaded steel columns in fire

In current Eurocode, the buckling temperature of steel columns can be calculated by either using an analytical approach or using a simple closed-form equation. This paper investigates the accuracy and limitations of those two calculation approaches. Test data on steel columns at elevated temperature reported in literature are used for comparison. The two approaches are found to give acceptable prediction for tests with moderate utilization factor, and unacceptable prediction for tests with either high utilization factor (μ0 > 0.83) or low utilization factor (μ0 < 0.16). The professional factor for the simple equation has a mean of 0.949 and a COV of 0.016, and can be best described by an extreme value distribution. The professional factor for the analytical approach has a mean of 1.018 and a COV of 0.013, and can be well described by either a normal, gamma or lognormal distribution.

► EC approaches to predict steel column buckling temperature are assessed by tests.
► Approaches give acceptable prediction for tests with moderate utilization factor.
► Probabilistic distributions of professional factors for the approaches are given.