Effectiveness of coupled thermo-mechanical damage modelling in steel structural fire engineering

Abstract

This paper explores the effectiveness and applicability of a newly developed thermo-mechanical coupled damage model for use in structural fire engineering. The damage-affected structural response of frame systems is accurately reproduced in this paper, which demonstrates the capability of the coupled damage model in giving a realistic representation of steel deterioration behaviour under combined actions of fire and mechanical loads. The coupled damage model is then used to assess the performance of a three-dimensional low-rise five-storey building and mid-rise ten-storey building with office occupancy under fire. Results provide a check of the office buildings for satisfying robustness requirements and give insight into the reasons that cause structural collapse. Compared to the conventional numerical approach, the consideration of coupled thermo-mechanical damage accumulation results in a substantial decrease in the time to collapse. A key finding from this study is that estimation of ultimate failure time by incorporating the coupled damage model with the recommended damage parameter sets has the potential to be utilized as a useful tool in helping designers to determine how much time is realistically available for evacuation before progressive collapse occurs in these types of buildings.