OPTIMIZATION OF REINFORCEMENT IN CLT PANELS BASED ON NUMERICAL STRESS-STRAIN ANALYSIS

Abstract

Cross-laminated timber (CLT) panels have gained widespread adoption in modern construction due to their combination of low weight, high stiffness, dimensional stability, and ease of assembly. Despite these advantages, their load-bearing capacity and deformation behavior largely depend on the internal structure and mechanical properties of wood, which is inherently anisotropic. To enhance the structural performance of CLT panels, reinforcement is commonly applied, which can significantly reduce deflections and longitudinal stresses, while simultaneously generating local concentrations of shear stresses near the reinforcing elements. This study presents detailed results of numerical modeling of CLT panels with varying reinforcement ratios (0.5%, 0.75%, 1.0%, and 1.25%) using the LIRA-SAPR 2024 software package based on the finite element method. The modeling accounted for wood anisotropy and employed both volumetric and rod finite elements. Panels with a total thickness of 10 cm, composed of five layers of boards arranged at 90° to adjacent layers, and a reinforcement spacing of 20 cm were analyzed. The results demonstrate that the introduction of reinforcement substantially reduces vertical displacements (up to 60%) and longitudinal stresses (over twofold) compared to unreinforced panels. However, the influence of increasing the reinforcement ratio on further deflection and stress reduction exhibits a diminishing effect, suggesting the existence of a conditionally optimal reinforcement level. In addition, local shear stress concentrations around the reinforcement were identified, which must be carefully considered during the design process to prevent potential local failures. The findings confirm the effectiveness of numerical finite element modeling for assessing the structural performance of reinforced CLT panels and provide practical guidance for optimizing their reinforcement design, contributing to safer and more efficient timber construction solutions.