Repair of Wood Trusses Loaded in Tension with Adhesively Bonded Garbon-Epoxy Patches

摘要

Wood and wood products are amongst the most important construction materials. Wood is generally used in frames, buildings, truss roof structures in buildings, bridges, towers, railroad infrastructures, and many more applications. Damage and failure behaviour of wood members in tensile, compressive, or shear loading are extremely important to account for in wooden structures subjected to high working stresses. Wood exhibits its greatest strength in tension in the grain direction. A few applications load a wood member in pure tension, such as trusses in the most varied applications. For a safe design, predictive methods and models for the simulation of the structural behaviour of these elements are required. One of the possible approaches is the finite element method. In this work, the tensile strength of adhesively bonded repairs with carbon-fibre reinforced plastic patches on wood members in pure tension is addressed experimentally and numerically. A parametric analysis was carried out on the overlap length (L_O) between the composite reinforcement and the undamaged region of the beam. The numerical analysis used the finite element method and cohesive zone models to simulate damage initiation and propagation in different materials such as the adhesive or wood in different propagation planes. The comparative analysis of the test results and the simulations showed a good correlation between both and provided design principles for these structures. An optimization technique to reduce stress concentrations and eventually increase the repair's strength was also tested numerically,consisting of adhesive filleting at the patch edges. Results showed that this technique can be used to increase the strength of the repairs.