Title:
The fire resistance of reinforced concrete structures
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Publication:
CIA
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DOI:
Date:
2/13/2011
Abstract:
Reinforced concrete building structures have traditionally been designed for fire resistance using very simple approaches. However there is a growing recognition that these methods may be oversimplified and that more sophisticated approaches could offer advantages by providing a more complete picture of likely behaviour. This paper reports on recent research into the performance of reinforced concrete structures in fire, illustrating the effects of two important phenomena – spalling and diaphragm action – not accounted for in the current simple approaches. These have been modelled using a highly non-linear finite element analysis developed specifically for structural fire engineering. The principal effect of spalling, which is notoriously difficult to predict, is to expose the steel reinforcement to higher temperatures, reducing its strength. Ignoring spalling is therefore unconservative. In contrast, tensile membrane action, which is also ignored in simple approaches, can significantly improve the survival of a fire exposed structure. The implications for the design of reinforced concrete structures are discussed.