Mechanical behaviour of facade systems in fire
Lead Research Organisation:
Imperial College London
Department Name: Mechanical Engineering
Abstract
Designers increasingly opt for glazed facades due to the appearance and performance of glass. Glazed facades are designed by regulation to resist gravity and wind loads and ensure a certain level of safety. However, their thermal and mechanical performance in a fire event is not regulated and is still poorly understood.
While the fire performance of glass as a component has been explored in recent years, very little work has been focused on the behaviour of glazed facade assemblies as a whole. This is because frames, spandrel panels and brackets are generally not considered as vulnerable to fire as the glass panels. This assumption however has not been verified. The metallic members are thin and can therefore heat up rapidly, causing a reduction in stiffness and strength, which can lead to excessive deformation.
Methodology
We will study the fire performance of curtain wall assembly via the finite element computational modelling software LS-DYNA. The façade members we will be investigating are aluminium extrusions used as framing and support of the glazed units. These framing systems can include some sections made from polymers called "thermal breaks". When heated these polymer parts will lose stiffness faster than the aluminium and will eventually melt compromising the whole framing system. We will also analyse the performance of brackets and mechanical fixings used to hang the façade from the main structure.
To validate our models, we will be running large scale experiment. These experiments will help us understand the interaction between members and the performance of the structure as an assembly of parts.
Objectives
- Investigate how glazed curtain walls and double-glazed façade perform in fire.
- Identify possible weak elements and failure mechanism of curtain wall systems.
- Gather information to guide façade engineers and architects in the design of more resilient facades that perform better when exposed to elevated temperatures.
- Collect experimental and visual data that will help understand the behaviour of complex façade systems.
While the fire performance of glass as a component has been explored in recent years, very little work has been focused on the behaviour of glazed facade assemblies as a whole. This is because frames, spandrel panels and brackets are generally not considered as vulnerable to fire as the glass panels. This assumption however has not been verified. The metallic members are thin and can therefore heat up rapidly, causing a reduction in stiffness and strength, which can lead to excessive deformation.
Methodology
We will study the fire performance of curtain wall assembly via the finite element computational modelling software LS-DYNA. The façade members we will be investigating are aluminium extrusions used as framing and support of the glazed units. These framing systems can include some sections made from polymers called "thermal breaks". When heated these polymer parts will lose stiffness faster than the aluminium and will eventually melt compromising the whole framing system. We will also analyse the performance of brackets and mechanical fixings used to hang the façade from the main structure.
To validate our models, we will be running large scale experiment. These experiments will help us understand the interaction between members and the performance of the structure as an assembly of parts.
Objectives
- Investigate how glazed curtain walls and double-glazed façade perform in fire.
- Identify possible weak elements and failure mechanism of curtain wall systems.
- Gather information to guide façade engineers and architects in the design of more resilient facades that perform better when exposed to elevated temperatures.
- Collect experimental and visual data that will help understand the behaviour of complex façade systems.
