Determining the effects of timber strength and wood species on the mechanical properties of CLT using non-destructive and destructive methods

This study aimed to determine the effects of production parameters such as wood species and timber strength classes on some mechanical properties of CLT panels using both non-destructive and destructive methods. Additionally, the study compared the strength values obtained from non-destructive and destructive testing methods on CLT panels and elucidated the relationship between them through regression analyses. CLT panels were produced using spruce and alder timbers, as well as hybrid panels formed from combinations of these two wood species. According to the TS EN 338 standard, the C and D strength classes of the timbers were determined non-destructively using an acoustic testing device. Among the timbers whose strength classes were determined, a total of 6 different strength classes were selected for spruce and alder. The bending strength, modulus of elasticity, and screw withdrawal force tests were performed on the CLT panel groups both non-destructive and destructive. As a result of the regression analyzes, the determination coefficient (R2) between non-destructive screw withdrawal force and destructive bending strength values varied between 0.6135–0,9997. Moreover, the R2 value calculated between non-destructive and destructive modulus of elasticity values for CLT panels was found to be between 0.7076–0.9997.