Local FRP reinforcement of existing timber beams

Timber beams in historic buildings tend to display signs of mechanical degradation in the form of large bending deformations and reduced capacity, often caused by timber defects. This paper addresses the assessment of the bending resistance of small timber beams subjected to static loads, before and after they have been reinforced using Fibre Reinforced Polymer sheets (FRP). The retrofitting of timber elements using FRP is not a new technique and several experimental research programmes have demonstrated that it is possible to increase the bending capacity of wood beams using FRPs. It is well understood that premature bending failure in timber beams and large bending deformations under loading are often caused by defects (e.g. splay or dead knots, shakes, etc.). This paper presents an experimental work where FRP sheets have been locally applied in the area where defects were noted. The structural response of locally reinforced timber elements when subjected to flexural loading was studied using a series of experiments. The results from the bending tests demonstrate that it is possible to partially restore the bending capacity of defective timber beams with the application of the reinforcement method proposed in this paper.