Timber steel-fibre-reinforced concrete floor slabs subjected to fire

Abstract

This paper presents a finite element model (FE model) for a numerical analysis of a composite steel-fibre-reinforced concrete (SFRC) slab with unprotected secondary timber beams subjected to fire, taking tensile membrane action into account. The material models were calibrated by material tests and push-out tests in a preliminary study, and then the FE model was validated against the results of a full-scale furnace test. The validated FE model takes into account geometric and material nonlinearity, mechanical damage due to thermal loading, and the nonlinear connection between the SFRC slab and the timber beams. A new material model was created to improve the simulated behaviour of the SFRC, especially in tension. The validated FE model was supplemented by a semi-probabilistic safety concept based on the Eurocode standards, and was applied to define the fire resistance of different variants of timber SFRC flooring subjected to fire with various slab dimensions and design loads. This approach will be used to create a catalogue in which the fire resistance will be defined for specific parameters of the structure, for example dimensions, loads and materials. The research presented in this paper follows up on a previous study, which was presented in 2014.