Effect of the Reinforced Plastic Clamp Fitting on the Bending Strength of the Spruce T-Type Loose Tenon Joints

Abstract

This article presents the bending strength and flexural properties of the glued T-type spruce loose tenon construction joints with and without reinforced plastic clamp fitting. Construction joints are designed according to Eurocode 5. The samples are made from European spruce (Picea abies Karst.) C24 class construction material with relative wood moisture 18% and relative wood density 410 kg/m3. Samples are assembled with water/high temperature resistant polyurethane adhesive and polyvinyl acetate dispersion adhesive. The total number of samples is 48. The sample width is 95mm and thickness is 45mm. Samples were subjected to moisture, weight controls and 48h stored in the climate chamber before practical bending load test. T-type loose tenon joint construction samples with reinforced plastic clamp fittings glued with polyurethane adhesive under bending load are 2.6% stronger and 13.8% less flexural then without reinforced plastic clamp fittings. T-type loose tenon joint construction samples with reinforced plastic clamp fittings glued with polyvinyl acetate dispersion adhesive under bending load are 9.7% weaker and 20% less flexural then without reinforced plastic clamp fittings. The accuracy of the developed bending strength, deformability and elasticity modulus of the examined construction joints was verified positively by experimental studies.