Experimental investigation of fire resistance of GLT beams

Mechanical and fire loading play together with geometric and material properties of glued laminated timber beams a decisive role in theoretical investigation into the time-dependent fire resistance of these elements. This is a multidisciplinary problem including heat conduction, water evaporation, internal gas pressure evolution, pyrolysis, volume change, etc. If properly calibrated, such complex models should allow us to forecast the evolution and shape of the charred or zero strength layer. It is doubtless that the calibration and validation steps require experiments. In particular, the results of large-scale fire experiment are discussed in this contribution focusing on the influence of fire intensity and duration on the temperature and the charred layer evolution. The influence of fire on stiffness and strength will also be addressed through the results of Pilodyn measurements of wood elastic modulus and three-point bending tests of original and fire-exposed beams.