Bending behaviour of cross laminated timber panels made from locally sourced spruce wood

Abstract

Cross laminated timber (CLT) is relatively new engineering wood product made by gluing cross-wise layers of solid timber boards to form large-scale panels. Due to excellent in-plane and out-of-plane resistance, CLT panels have become very common as wall and floor structural elements. CLT is validated as an excellent alternative to more traditional construction materials like reinforced concrete and steel for use in single- and multi-storey buildings. This paper presents an experimental study conducted on five-layer CLT panels manufactured using spruce boards. The panels were tested in four-point bending configuration, loaded in the out-of-plane direction. Bending behaviour of CLT panels in the major axis orientation was evaluated through failure modes, load-deflection relationship, ultimate moment capacity, stiffness and strain distribution profile. The obtained experimental results indicated brittle failure modes and linear load-deflection relationship up to failure. In addition, strain distributions of panels were quite linear during the entire loading, confirming the assumption that plane sections remain plane after bending. Bending response of CLT panels was also investigated using finite element modelling. The stress and deflection analysis was executed in the RFEM software using the RF-LAMINATE module. The calculation was carried out according to the laminate theory, taking into account shear coupling of layers. A good agreement between the results of numerical model and experimental investigation was found.