Performance of concrete in fire: a review of the state of the art, with a case study of the windsor tower fire

This paper provides a “State of the Art” review on current research into the effects of fire exposures upon concrete. The principal influences of high temperature in concrete are loss of compressive strength and spalling, the forcible ejection of material from a member. Though a lot of information has been gathered on both phenomena, there remains a need for a broader understanding of the response of concrete structures to different heating regimes and the performance of complete concrete structures subjected to realistic fire exposures. There is a lack of information derived from large-scale tests on concrete buildings in natural fires. Besides undertaking further fire tests, lessons can also be learnt from real fires and the University of Edinburgh has embarked upon detailed studies of the serious fire in the Windsor Tower, Madrid. In order to properly characterise the fire and the performance of the structure a data-gathering exercise has been undertaken and computer modelling tools are being applied in order to obtain better insights into the structural response. There remains some uncertainty about the precise mechanism of fire spread, but an external route is likely, facilitated to some degree by the glazed curtain walling construction; lack of fire protection on the steelwork was the major reason for the subsequent partial collapse of the upper floors and the localised failure of a concrete portal frame can be attributed to the same reason.