Computational study of failure of curtain wall facade systems exposed to fire
File(s)
Thesis with shorter abstract
Author(s)
Lugaresi, Francesca
Type
Thesis
Abstract
Fires involving building facades pose challenges for fire safety engineers and the fire service. This thesis examines the critical, yet often overlooked aspect of mechanical failure in facade systems during fires. The impact of fire on the structural integrity of the facade is critical for safe evacuation and fire-fighter access, particularly for tall buildings where facade elements falling off the building pose a life threat and swift evacuation is essential. High-profile fires in buildings with curtain walls, such as the Mercantile Credit building and the Relay building, highlight these dangers.
The absence of reliable tools for predicting the failure of facade systems during fires prompted this research. Focusing on the failure mechanisms, various facade support systems were examined. A comparative analysis of the mechanical and thermal properties influencing the failure of non-combustible components is presented. Through computational models, the thermal response of curtain wall framing systems to fire exposure is studied. Validation against experimental data, alongside a sensitivity study, enhances the reliability of the model’s predictions. The exploration of the role of screw connectors, thermal breaks and gaskets, gives insights on the complex interactions defining the system’s thermal response.
The mechanical behaviour of a generic curtain wall frame was analysed, focusing on thermal degradation, load-bearing and buckling failure. Simulation results reveal that failure mode is influenced largely by both material and level of restraint. Aluminium mullions fail at temperatures from 170°C to 400°C, while transoms, due to shorter and stockier profiles, fail at lower temperatures. Stainless steel transoms fail due to extensive deflection, while carbon steel performs best but is not commonly used due to corrosion concerns.
These findings advance our understanding of curtain wall frame behaviour during fires. By identifying optimal fire protection measures and systems with increased fire resistance, this research aims to enable...
The absence of reliable tools for predicting the failure of facade systems during fires prompted this research. Focusing on the failure mechanisms, various facade support systems were examined. A comparative analysis of the mechanical and thermal properties influencing the failure of non-combustible components is presented. Through computational models, the thermal response of curtain wall framing systems to fire exposure is studied. Validation against experimental data, alongside a sensitivity study, enhances the reliability of the model’s predictions. The exploration of the role of screw connectors, thermal breaks and gaskets, gives insights on the complex interactions defining the system’s thermal response.
The mechanical behaviour of a generic curtain wall frame was analysed, focusing on thermal degradation, load-bearing and buckling failure. Simulation results reveal that failure mode is influenced largely by both material and level of restraint. Aluminium mullions fail at temperatures from 170°C to 400°C, while transoms, due to shorter and stockier profiles, fail at lower temperatures. Stainless steel transoms fail due to extensive deflection, while carbon steel performs best but is not commonly used due to corrosion concerns.
These findings advance our understanding of curtain wall frame behaviour during fires. By identifying optimal fire protection measures and systems with increased fire resistance, this research aims to enable...
Version
Open Access
Date Issued
2023-12-22
Date Awarded
01/12/2024
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Rein, Guillermo
Sponsor
Engineering and Physical Sciences Research Council
Grant Number
EP/S513635/1
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)