Tests, simulations and design of aluminium alloy equal-leg angle section stub columns after exposure to fire

Abstract

This paper reports experimental and numerical studies on the compression resistances of aluminium alloy equal-leg angle section stub columns after exposure to fire. An experimental programme was first conducted, including heating tests, eight post-fire material coupon tests and sixteen post-fire stub column tests. Following the experimental programme, a numerical modelling programme was conducted, where finite-element models were developed and validated. The validated models were then used to perform parametric studies to derive additional numerical data. Based on the obtained test and numerical data, the relevant design rules used in Europe, China, America, Australia and New Zealand as well as the continuous strength method were assessed. The assessment results generally show that the current international standards lead to significant conservative and scattered design resistances when used for the post-fire design of aluminium alloy equal-leg angle sections under compression, particularly for those after exposure to elevated temperatures of 300 °C to 550 °C, due to the neglect of significant post-fire material strain hardening. The continuous strength method is found to provide greatly improved design accuracy and consistency over the European, Chinese, American and Australian/New Zealand standards for the post-fire design of aluminium alloy equal-leg angle sections, since it accounts for the post-fire material hardening.