Bending Performance of Box-Based Cross-Laminated Timber Systems

Cross-laminated timber (CLT) is a growing phenomenon and a recent building solution alternative in timber construction in North America by using massive or solid wood plates as roof, floor, and wall elements. In this paper a variation of the conventional CLT is considered by studying the performance of box-based CLT systems, which refer to box beams with multiple voids. In some loading situations, such as out-of-plane bending, these systems, which can reduce structural weight without significant loss of strength or stiffness, may be structurally efficient and cost competitive. Comprehensive three-dimensional finite-element models, which can be used to analyze the mechanical behavior of such box structures, were developed. Four prototype layups, each having five replicates, were designed, manufactured in-house, and tested under symmetric four-point bending (also known as third-point loadings). The numerical analysis agreed well with experimental data in terms of vertical deflection and flexural rigidity. This paper contributes to the understanding of the structural performance of box-based CLT systems for the commercial and residential applications.