Composite repair of timber structures

Experimental and numerical evaluation of composite repairs on wood beams damaged by cross-graining

“…Wood is amongst the oldest construction materials in the world and has been widely used to build large-scale structures like bridges, railroad infrastructures, lightweight warehouses and residential buildings [1,2]. This natural and renewable material is characterized by high strengths under parallel to grain tension and compressive loads, which are nearly unique as specific properties (i.e., divided by its weight).…”

“…Poor initial design or construction, or short duration episodes such as overloads and earthquakes, can also be pointed out as origins of damage [8]. Some studies were published in the last decades about the reinforcement [9] and repair [2,6] of wood structures with aluminium/steel and composites. In recent years, composite materials, which are already extensively used in several high performance applications in the aerospace, automotive, marine and military industries (Carbon-Fibre Reinforced Plastics; CFRP), and in house-hold and leisure appliances (Glass-Fibre Reinforced Plastics; GFRP), are gaining acceptance for structural strengthening and repair.…”

“…Oppositely to the reinforcement studies, not many works were carried out in recent years on the repair of wood structures with composites, and the ones available are limited to experimental analyses. Moreover, most of the proposed techniques are not specifically suited to in situ application and require the damaged members dismantlement, making them less appealing [2]. On the other hand, it is unrealistic to apply available empirical results for the repair of timber structures, since much of the research is based upon timber reinforcement rather than repair [16,17].…”

“…The available techniques involve adding a bolted or fastened member in parallel, stitch bolting, inserting steel or fibreglass dowels, epoxy filling approaches, bonding of thin composite plates on the beam exposed faces and wrapping of the beams with composites at the damaged region [18]. Radford et al [2] proposed a repair methodology for slender wood beams damaged by a longitudinal crack along their length. Steel nails or GFRP pultruded rods were adhesively-bonded through the beams thickness.…”

“…This mechanism is characterized by a tensile fracture at a small angle to the beams longitudinal axis, due to a small misalignment between the wood fibres and the beam axis [2,21]. This can occur in large-scale in a wood member when trees that have grown spirally or with a pronounced taper are cut for lumber.…”