Experimental investigation of cross-laminated timber deep beams with and without large openings

Cross laminated timber walls in buildings may be required to act as deep beams as part of permanent transfer structures or as an alternative load path in the event of the accidental loss of supporting structure below. The capacity and behaviour of cross laminated timber panels loaded in this configuration is not well understood and a database compiled as part of this study indicates that experimental studies on full-size panels are absent from the literature. In this study, full- and quarter-size cross laminated timber panels, with and without openings, were tested to failure as deep beams in three-point bending. Experimental stresses are calculated according to beam theory and compared to expected values of resistance. The study shows that cross laminated timber panels exhibit considerable capacity in a deep beam configuration but that existing methods underestimate this resistance, particularly resistance to net shear. The high capacity of full-sized CLT deep beams, with and without openings, demonstrated in this study, suggests significant potential for the use of CLT 'walls' as deep beams, enabling the design of more efficient and resilient CLT structures.