Sonic testing on cross laminated timber panels

Cross Laminated Timber (CLT) panels are used as building construction materials due to their excellent properties. In particular, with this construction technique it is possible to produce high quality structural members by assembling normal/low quality planks. Timber boards should be graded according to the current regulations before their use as structural components. Among grading methodologies, non-destructive Sonic Testing can be applied. Sonic Testing is a non destructive technique widely used for building material quality control. In this paper, the reliability of Sonic Testing in giving information on some mechanical characteristics of Cross Laminated Timber panels is discussed also in relation to wood type, layers number and layers configuration of the panels. For this purpose, both Sonic Testing and destructive bending tests have been carried out on several CLT panels manufactured by using boards of Spruce and Sardinian Maritime Pine. Regression analysis between sonic and mechanical parameters (static modulus of elasticity and bending strength) has been performed and is critically discussed in the paper.