D.I.C.E.A.A. - Dipartimento di Ingegneria Civile, Edile-Architettura e Ambientale
Experimental out-of-plane, four-points bending tests were performed on two series of 3-layered Cross Laminated Timber (CLT) panels
made of Calabrian Beech and Calabrian Beech and Corsican Pine respectively. The predominant failure mechanism was rolling shear along
the inner layer and the glue line. A linear elastic model of a 3-layered, CLT panel was developed to describe the stress distribution
in CLT slabs in bending, with a focus on their load-bearing performance before the propagation of cracks. In the analytical model,
each timber layer was defined as an Euler-Bernoulli beam. The two glue lines were modeled using extensional springs, infinitely rigid
in the direction perpendicular to the beam’s axis, and with a defined stiffness in the tangential direction. The outer layers are
assumed axially flexible while the inner one is regarded as axially rigid. The results of the proposed model were thus compared and
validated with the experimental evidence and with additional FE numerical predictions given by 3D numerical simulations carried out
in Abaqus.
This paper investigates the buckling behavior of three-layered cross-laminated timber (CLT) panels, from both the experimental and
analytical standpoints. Two diferent series of specimens are considered: the homogeneous ones, which are entirely made of beech, and
the hybrid ones, whose inner layers are made of Corsican pine. The experimental tests aim to evaluate the failure limit loads of the
specimens, when loaded by an increasing compression tip force. The analytical formulation is frst obtained for a panel with a generic
number of layers and after it is specialized for a three-layered panel. Timber layers are modeled as internally constrained planar
Timoshenko beams linked together by adhesive layers, which are modeled as a continuous distribution of normal and tangential elastic
springs. A closed-form solution of the buckling problem is obtained. The achieved Eulerian critical load of CLT panels depends on
two parameters, which account for (1) the interaction between timber layers (due to the glue tangential stifness) and (2) the rolling
shear stifness of the inner layer. Three diferent failure criteria are introduced to estimate the limit load. Finally, the analytical
limit loads and the experimental ones are compared.
