THEORETICAL STUDY OF DEFLECTIONS OF COMBINED CROSS-LAMINATED TIMBER PANELS CONSIDERING CREEP
DOI:
https://doi.org/10.31650/2707-3068-2025-29-148-156Keywords:
cross-laminated timbe, secondary timber, composite wood materials, creep deformations, deflectionsAbstract
This study investigates the structural behavior of cross-laminated timber (CLT)
panels incorporating secondary-origin wood-based composite materials (LVL and OSB) in their transverse layers. The research aims to evaluate how such modifications affect the panels' stress distribution and deformation characteristics compared to conventional solid-wood CLT panels. The methodology relies on Mindlin-Reissner plate theory, accounting for shear deformation effects in layered orthotropic materials through numerical finite element method modeling using RFEM 5 software.
Three-layer and five-layer CLT panel configurations with spans of 3m, 4m, and 5m were analyzed under uniform loading conditions (100 kg/m²). The experimental models compared traditional all-solid-wood panels with innovative designs featuring OSB-3 (18mm) and LVL 36C (24mm) in non-load-bearing layers. Material properties were adjusted to consider long-term creep effects using deformation coefficients according to Eurocode standards for Service Class 1 conditions.
Key findings reveal that engineered wood products in transverse layers cause no significant
changes in internal stress distribution patterns while panel thickness remains the dominant factor affecting load-bearing capacity at equal spans. Creep deformation increases total deflection by 47-63% across all panel types, with the most pronounced effect (up to 61.1%) observed in LVL-modified panels. Three-layer composite panels show 10-25% higher deflections than conventional CLT, while five-layer configurations demonstrate better performance stability.
The study confirms the technical feasibility of using secondary-origin wood composites in CLT production, potentially contributing to circular economy principles in construction, improved resource efficiency through utilization of low-grade timber and reduced environmental impact of building materials. However, the significant creep effects (1.5-1.6 deflection increase) necessitate careful consideration in design practices. The results provide a foundation for future research on hybrid CLT optimization and standardization of calculation methods for sustainable timber construction.
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