Experimental and numerical behaviour of cross-laminated timber floors in fire conditions

The paper investigates the thermal and mechanical behaviour of cross-laminated timber (crosslam) floor panels exposed to fire. The results obtained from large-scale tests performed at ambient temperature and in fire conditions are presented. In the tests in fire conditions, both unloaded and out-of-plane uniformly loaded panels were tested. Further, some panels were protected with different cladding systems to improve their fire performance. Finite element models were implemented in Abaqus software package to simulate the experimental tests and to analyse the thermal and structural performance of protected and unprotected crosslam floor panels. The temperature-dependent relationships for wood properties proposed by the European code for fire design of timber structures were adopted in the modelling. Wood was assumed as a non-linear isotropic material. The falling-off of the protective layer was simulated numerically as observed in the experiments. Numerical results in terms of mid-span deflection, temperature and stress distributions along the depth of a crosslam panel are presented. By comparison with experimental results, an accurate numerical prediction of the fire resistance of crosslam floor panels was attained.