Behaviour of Cross-Laminated Timber Slabs Subjected to Fire-A State-Of-The-Art Review

In a new era, full of possibilities for manufacturing large timber sections made of engineered wood, such as cross-laminated timber (CLT), the strength and structural integrity of mass timber sections can be retained for a much longer time in fire. Increased availability of CLT in Canada and its successful use in mass timber construction worldwide have generated interest in its properties and performance when subjected to fire. There are many benefits of using CLT, such as utilizing sustainable and renewable construction materials like wood and the fact that CLT has excellent acoustic, thermal, and seismic performance. However, having a product with a broad portfolio of choices brings many difficulties, specifically in terms of how the number and thickness of the lamellae of a CLT slab can affect its fire performance. This chapter summarizes the most recent research on the behaviour of CLT floor slabs when exposed to fire. The review of the state-of-the-art literature discusses different experimental works examining the change in internal temperatures, char depth and progression, and structural integrity of CLT floor slabs when subjected to fire. The reviewed research studies varied in the scale of testing, test setup, make-up of CLT sections, and wood species utilized. Despite the variances across the different reviewed studies, many of the same conclusions were drawn, providing consistency in the general outcomes. Although experimental testing is the ground truth to verify the fire resistance of construction materials and structural assemblies, fire testing is time-consuming and costly. This demonstrates the need for developing computer models that can accurately simulate the actual behaviour of CLT slabs when subjected to fire. Accordingly, this chapter also discusses recent numerical and modelling attempts to simulate the behaviour of CLT slabs when subjected to standard and natural fire scenarios.