Bending and compressive properties of cross-laminated timber (CLT) panels made from Canadian hemlock

Abstract

Cross-laminated timber (CLT) is an innovative engineering wood panel product made from gluing layers of solid-sawn lumber at perpendicular angles. Owing to the excellent structural rigidity in both orthogonal directions, CLT becomes a preferred construction material for shear walls, floor diaphragms, and roof assemblies. CLT is normally made of Spruce-pine-fir (SPF) lumber or Douglas fir-Larch lumber. Recently, attempts have been made to manufacture CLT with Canadian hemlock. This paper investigates the out-of-plane bending properties and compressive properties of CLT panels made from Canadian hemlock. The mechanical properties of the CLT panels in the major/minor strength directions were obtained through experimental tests, and numerical models were developed to predict bending stiffness and ultimate load resisting capacity of the CLT panels. Moreover, theoretical bending stiffness of the CLT panels was calculated according to the equations provided in different code provisions, and the calculated values were compared with the experimental data. Results show that CLT panels made from Canadian hemlock perform as well as those made from other common used lumber species (i.e. SPF or Douglas fir), and the bending stiffness and ultimate load resisting capacity of the CLT panels can be predicted by the developed numerical models. In addition, in the major strength direction, the global bending stiffness of the panels can be predicted using the theoretical bending stiffness. In the minor strength direction, the local bending stiffness of the panels can be predicted using the theoretical bending stiffness calculated according to the Shear Analogy theory. The results presented in this paper can provide fundamental basis for supporting the potential engineering application of CLT panel products made from Canadian hemlock.