Fire Resistance in Cross-laminated Timber : Brandmotstånd hos korslaminerat massiv trä

Abstract: This report deals with the fire resistance of cross-laminated timber (CLT). Themain purpose is to verify a new model on CLT and its ability to sustain itsbearing capacity when exposed to fire. To establish this, a series of bendingtestshas been conducted in combination with fire exposure of the CLT. Twodifferent series, with different dimensions, of beams were tested (series 1 andseries 2). Four basic set-ups: CLT in tension or compression, either equippedwith fire protective covering or not. Results from the tests has been gatheredand evaluated to verify the theoretical model of the fire resistance. Evaluationwas made through analysis of the residual cross-sections of the beamsregarding charring depth and rate and moment of inertia (I).Results of the tests verify to a large extent the Design model. Externalproblems and variations in the beams themselves caused some deviations.Analysis confirmed the CLT as being more similar to other laminated productssuch as Laminated Veneer Lumber (LVL) then homogenous solid beams. BothCLT and LVL experience delamination when exposed to fire resulting in anincreased charring rate. The difference in rate when using Gypsum plaster as aprotective barrier against the fire exposure is also equal to LVL.The results of the report will be used in the new version of the EuropeanStandard, Euro Code 5 and in the third edition of Fire Safe Timber Buildings.Charring rates proved to be less than expected but the CLTs ability to withstandfire while keeping its bearing capacity