International audienceCross Laminated Timber (CLT) panels are more and more common in timber construction. When submitted to out-of-plane loads, their main structural issue is the low transverse shear strength of cross layers which leads to rolling shear failure [1, 2]. The absence of specific standards yields to CLT panels having lateral boards glued each other or not, depending on the producer. The resulting discontinuities in the non-gluing case influence the global mechanical response [3]. In addition, the timber construction market requires new technical solutions for CLT. Periodic voids within the panel lead to lighter and more thermally efficient floors. However this geometry increases the panel’s heterogeneity and the difficulties in predicting the actual bending behaviour, especially the shear effects.In the first part of this work we focused our attention to a CLT layer having weak heterogeneities, namely the gaps between boards. These heterogeneities are taken into account by means of a (fictitious) equivalent and homogeneous CLT layer which mechanical properties are defined with respect to the board’s reference frame. Such an equivalent layer is combined with the exact 3D solution for laminated plates in bending [4] and a failure criterion for wood [5]. The predicted behaviour is in good agreement with a reference experimental test [6] in terms of global stiffness and variation of failure modes within the apparent elastic regime. The validated model is therefore used to investigate the influence of varying some panel’s properties on the bending response.Innovative CLT panels having periodic voids (filled by an isolating material) are already in production. An experimental campaign proved how this lay-up increases their shear weakness. The ratio wood/void can approximate the reduced elastic properties of these strongly heterogeneous panels. This approach has been already used [2] with design method for CLT in bending [7] and can be simply implemented in the Equivalent – Layer model. As a starting point we aim to compare the experimental behaviour with the predicted one using reduced mechanical properties by the ratio wood/void. These properties are combined with the model developed for weak heterogeneities and design methods for CLT in bending [7, 8].Nevertheless, such a simplified approach can’t reproduce the complexity of stresses’ and strains’ distribution, especially transverse shear ones. Therefore a more accurate model is currently in development. This solution can precisely predict the influence of high heterogeneities by means of a periodic homogenization scheme. Panel’s reduced elastic properties (EI – GA) derived with such an advanced modelling can be finally used for practical design of bending members
