Experimental Investigation of Cross Laminated Timber Beams with Vertical Outer Layers

The geometrical dimensions and mechanical properties of lintel beams can significantly impact both the kinematic behaviour and failure modes of cross-laminated timber (CLT) shearwalls with cut openings. Although CLT lintel beams can be conceptualized as a flexural element, the lay-up of lintels in shear walls with cut-out openings is intrinsically unfavourable to withstand bending moments due to the outer laminations being oriented vertically. Although great efforts have been made to investigate the mechanical behaviour of CLT beams with horizontal outer lamination, the information on CLT beams with vertical outer layers is still scarce. This study presents a comprehensive experimental campaign to investigate 42 CLT beams, 36 of which were constructed with vertical outer layers, and consisting of two different lay-ups. Analytical models, originally developed for CLT beams with horizontal outer layers, are evaluated for adoption to CLT beams with vertical outer layers in order to propose a methodology to determine their resistance and stiffness parameters. The proposed models were successfully verified against data obtained from the current study and those available in the literature. The study showed that existing models developed for bending, gross shear and net shear strengths of CLT beams with horizontal outer laminations can be adopted without any adjustment to CLT beams with vertical outer laminations, while, existing analytical models to calculate the torsional strength had to be readapted.