Fire safety of modern buildings is crucial and the fire safety design of these buildings has been a challenging task. Large open-plan compartments are commonly designed in modern urbanisation and the fire behaviour in such compartments is different from the traditional knowledge built upon small compartment fire research. Various experimental studies have been performed to represent such fires to evaluate the structural fire resistance, which were accompanied by a series of travelling fire models to describe the non-uniform fire impact in large compartments. However, the localised fire models adopted in the latest travelling fire methodology were derived from localised fire tests of unconfined ceiling boundaries. The effects of smoke generation due to fire during various stages of the fire development are not included explicitly. This paper characterises the thermal impact on structural members from the localised fire tests and extends the simulation models and analysis approaches to localised fires in large compartments. Comparing the cases with soffits and without soffits, temperature differences of up to 150 °C are observed and the convective coefficient adopted as 35 W/m2K is too high. The work recommends to modify the current localised fire models to consider realistic fire sizes and smoke layer with the recognition of semi-confined conditions in large compartment fire scenarios. By including these aspects, it is possible to establish more universal design fire models to overcome the current limitations and to address the fire impact in compartments of various sizes and ventilation conditions.@en

The role of “travelling fires” is to ensure the robustness of structural design with large compartments under realistic fires, having a fire plume at the near-field, and a hot smoke layer preheating the ceiling at the far-field. Once the fire travels, the near-field has a leading edge representing the fire spread, and a trailing edge representing the burnout of the fuel. Though well understood by its definition, the mainstream of efforts on travelling fires for structural response is limited to 2D finite element modelling (FEM). This paper aims to identify the importance of slab inclusion with a 3D FEM structural model for steel-composite structures under travelling fires, with a special emphasis on the significance of ignoring the slab structural capacity contribution from a 2D simplified structural model. The role of fire protection scheme for 2D model against the 3D model on numerical predictions was also explored. It was found that the structural load path, and the potential structural failure mechanisms could be fundamentally different between the 3D model and the 2D model, i.e., with or without slabs. Although the 2D model tends to predict larger deflections (i.e. more conservative) than the 3D model, it could also significantly underestimate the large internal forces from the beams, which might overlook the connections failure under travelling fires. Further, due to the simplification of the 2D model omitting the significant stiffness contribution from the slab, the effect of the fire protection is likely to be amplified. It may be misleading for the performance-based structural fire design under different travelling fire scenarios. Hence, the 3D model is likely to be considered as necessary and feasible for structural fire analysis for travelling fires as a complement to the 2D model approach.@en

First respondents to fires in structures face severe risks as both the fire and structural behaviour are unpredictable. While structural collapse may manifest some warning signs, these signs are not always easily identified which has led to the death of many fire fighters over the years. Both fire and structural fire simulation have come a long way and are now capable of assessing the thermomechanical behaviour of structures to a good degree of accuracy. However, such simulations take hundreds or thousands of engineering and computation hours. This paper explores performing these analyses a priori and using the generated database to train a recurrent neural network for real time prediction of potential failure. The analysis is performed on an aluminium reticulated roof structure that is constructed in Sichuan Fire Research Institute (Sichuan, China) and is expected to be tested to failure in fire in 2023. One hundred localised fire scenarios were used to cover the potential fire that will be used to induce the failure of the test roof. Heat transfer analyses for each section were then performed in OpenSEES followed by thermomechanical analysis in the same software. The generated results database was then cleaned and the data at several key locations were extracted and used to train a long short term memory recurrent neural network. The results of the predictions show that the artificial intelligence model can infer results with increasing accuracy the closer the structure is to failure. The real test of the accuracy of the model, however, will be during the fire experiment on the real structure. This would be the first time an artificial intelligence model for rapid forecasting of structural response in fire is built a priori and tested against a real fire.@en

In the recent development of the performance-based structural fire design, the “travelling fire” methodology has been gradually accepted as a necessary fire boundary condition. However, its application is still limited by uncertainties in the selection of different design travelling fire parameters, which result from the lack of relevant experimental data and corresponding validated structural finite element models which can be used in advanced travelling fire methodologies, e.g. the extended travelling fire methodology (ETFM) framework. This paper aims to fill this gap through modelling a prototype steel-composite floor structure (regarded as a 'slice' of a large open-plan office), to investigate its true structural response under a wide range of travelling fire scenarios, with an emphasis on considering the effect of concrete slabs in a 3D finite element model, using LS-DYNA. To ensure the credibility of this numerical study, the model was validated against the experimental data from the Veselí Travelling Fire Test, and comparisons made with similar modelling efforts using Vulcan. In the parametric studies, eight cases were examined to investigate the structural response and the failure criteria, related to the selection of different key design parameters for the travelling fire within the ETFM framework, i.e. fire spread rate and inverse opening factor. It was found that solely satisfying the critical temperature (e.g. 550 o C for steel) and deflection criteria (e.g. beam span over 20) for the structural members might not guarantee a safe structural design for travelling fire scenarios, and it is suggested that the steel yielding stress status during the cooling phase in tension should also be examined. Compared to the inverse opening factor, it appears that the selection of fire spread rates is likely to be more critical in identifying the worst travelling fire scenario for the structural response with fire protection.@en