Alternated cross-laminated timber (aCLT) panels: development and mechanical characterization

A novel type of wood-based panel for structural applications is presented. Such panel named as alternated cross-laminated timber (aCLT) is based on the cross-laminated timber (CLT) panel concept but with a modified internal architecture, in which the cross-layers are replaced by hybrid layers composed of the traditional cross-lamellas alternated with in-line lamellas—as in glued laminated timber (GLT). Such modification aims to improve stiffness and strength in the main direction of the panel in comparison to the traditional CLT concept. To study the referred panel concept and its behavior, a series of panel stripes specimens (beams) of the new panel concept, as well as of CLT and GLT, were produced with 3 and 5 layers. An experimental campaign was performed to determine: (i) the Young`s modulus of the lamellas; (ii) the shear modulus and strength of the cross/hybrid layers of the panels and; (iii) the force vs. deflection of the beams in bending for the determination of bending and shear stiffness and strength. The data obtained in (i) and (ii) was inputted into a developed finite element (FE) model and the results from (iii) were used to validate the models. The FE model was later used to compare the performance of CLT and aCLT of equivalent thickness for a practical case. The results revealed a slight reduction in deflection (between 2 and 11%) and normal stress (1–7%) and a more substantial reduction in shear stress (between 28 and 94%) against the CLT solutions.