Structural fire engineering considerations for cross-laminated timber walls

The current understanding of the thermo-mechanical response of cross-laminated timber (CLT) walls to fire is insufficiently developed. This paper presents results obtained using a novel experimental methodology on fireexposed CLT walls under sustained loads. The findings demonstrate that global instability is likely to be the dominant failure mode for CLT walls in fire. Use of a polyurethane adhesive resulted in earlier structural failure than use of a melamine urea formaldehyde adhesive. Three-ply walls failed significantly earlier than those with five plies. The combination of these two factors caused a halving of failure time between different walls under identical heating conditions. In addition, CLT walls were found to collapse during artificially induced cooling phases. It is concluded that these findings are centrally relevant considerations for fire design of CLT.