The effect of edge gaps on shear strength and rolling shear modulus of cross laminated timber panels

Abstract The effect of gaps between boards in transverse layers of cross-laminated timber (CLT) on shear strength was investigated. Five-ply specimens with gaps of 0, 6, 89 and 178 mm were subjected to short-span three-point bending tests. Digital imaging correlation (DIC) was used to quantify strains and displacements in core layers. Panel shear capacity met the requirements of the PRG 320 standard for performance-rated CLT for the gap sizes tested, suggesting that small gaps do not reduce shear strength enough to warrant consideration in design. DIC data and Timoshenko beam theory were used to estimate rolling shear modulus and specimen deflections, which agreed well with measured values.