Optimising design decision-making for steel structures in fire using a hybrid analysis technique

Abstract

Steel structures can be protected against the effects of fully-developed fires by the use of sprayed on materials, board systems and intumescent paints, etc. or by using sufficiently large unprotected elements. This paper presents how optimum decisions for the protection of steel structures in fires can be achieved in a performance-based design environment, given conflicting structural fire design decision criteria and multidisciplinary fire design stakeholder views. In particular, a novel hybrid analysis approach is proposed for combining stakeholder views on the different fire protection options and the numerical outcomes of structural fire analysis. As for the stakeholder views, reference is made to benefits and costs criteria priorities for assessing competing options resulting from a previous study from the same authors. The fire protection structural performance is numerically and probabilistically assessed according to a parametric study. The proposed approach is exemplified by making reference to a limit state structural fire design of single steel elements. A synthesis and ranking technique is then applied to integrate the qualitative results obtained in terms of benefits and costs priority scores; and the quantitative measures of failure probabilities and costs for the different fire protection options. The results show that the ranking technique accounts for multidimensionality in synthesising the structural fire design decision problem. The results also show that intumescent paints and board systems are the most cost-effective options in different stakeholder influence scenarios, given a general selection of steel structural fire protection. The hybrid technique is proposed to support an optimal and cost-effective structural fire design decision-making for buildings in a performance-based design environment.