Einfluss des Klebstoffes auf das Brandverhalten von Brettschichtholz

Influence of the adhesive on the fire behaviour of glued laminated timber.

Adhesives are commonly used to produce engineered wood products such as glued laminated timber beams. The load-bearing capacity of these structural timber elements is strongly influenced by the adhesive used. As a consequence, adhesives have to meet requirements regarding strength and durability to ensure the functionality of structural timber elements during the whole lifetime. Also during fire, the performance requirements have to be fulfilled for a certain time period. To investigate the influence of the adhesive on the load-carrying capacity of glued laminated timber in fire, comprehensive analysis has been performed. This article summarises the most important results and findings. Based on the numerical analysis performed to investigate the influence of adhesive in the bondline between two lamellas, it can be concluded that also if the adhesive strength in the bondline is strongly influenced by the temperature, in most common design applications failure will occur because the bending resistance of the beam is exceeded. Failure in the bondline is hardly to be expected. The fire tests on finger-jointed timber boards showed that the fire resistance is dominated by the type of failure. Taking into account the different failure modes, no significant difference was observed between the adhesives studied.