Thermo-mechanical analysis and validation of SAFIR for historic forms of construction

Purpose The advanced finite element software SAFIR has been extensively validated and benchmarked against the cases set out in the German National Annex for EN 1991-1-2 (2010) (DIN EN, 1991-1-2/NA, 2010; Wald et al., 2012; Ferreira et al., 2018a; Zaharia and Gernay et al.; Ferreira et al., 2018b; Pintea and Franssen, 1997). The existing validation studies focus on recent forms of construction and are not necessarily relevant to historic structures. This paper explores the use of advanced numerical techniques to estimate the anticipated fire behaviour of existing floor systems used in historic buildings in the UK. The main objective is to benchmark the numerical model against standard fire resistance test data for historic floor constructions. Design/methodology/approach The methodology involves using SAFIR software to validate the thermo-mechanical behaviour of historic types of floors using standard fire resistance test evidence. The numerical analysis is based on two steps. In the first step, a heat transfer analysis is performed to determine the heat distribution through the floor section. In the second step, the mechanical analysis is performed based on the temperature output from the thermal analysis, which considers a reduction of the material properties at elevated temperatures. Findings This paper provides a thorough examination of standard fire resistance test data for filler joists and hollow pot floors, which were conducted as part of the Investigation of Building Fires study in the UK during the 1950s. The overarching objective of the paper is to validate the applicability of modern numerical tools such as SAFIR software in evaluating the thermo-mechanical performance of historic forms of construction. Through the thermo-mechanical analysis and validation exercises, this paper demonstrates the accuracy of advanced numerical techniques in evaluating the fire behaviour of historic forms of construction. Specifically, it aims to validate numerical methods by comparing them against fire resistance test data, focusing on two significant historical floor types: filler joists and hollow pot floors. The analysis presented in the paper shows that the formulation for the material properties (steel and concrete) from the Eurocodes can accurately capture the behaviour in fire of the two floor systems. Research limitations/implications One limitation is that these numerical methods cannot predict local integrity failure (e.g. cracking or spalling) or the effects of undetected defects. Originality/value The study presented in the paper highlights the potential of applying advanced numerical techniques to enhance the understanding and evaluation of the fire performance of historical elements of structure. This not only facilitates more accurate assessments of fire resistance but also offers invaluable insights for architects, engineers and preservationists involved in the conservation and refurbishment of historic buildings.