Experimental tests and numerical analysis of historic bent timber elements reinforced with CFRP strips

The paper presents the results of studies proposing to use carbon fibre reinforced polymer (CFRP) strips to reinforce beams with defects (biological corrosion, inclusions, slope of grain, cracks) in order to restore their load-bearing capacity. The proposed solution, consisting in bonding CFRP strips into the cross section, is suitable for restoration work in historic buildings. Moreover, owing to the fact that the reinforcing inserts are situated inside the cross section, the possibility that the adhesive strip–wood bond will delaminate is reduced and the fire resistance of the element is increased. The increase in the load-bearing capacity of the tested beams amounted from 21% to over 79%. The results of an analysis of the static behaviour of the reinforced cross sections, carried out using numerical modelling and the finite element method, are presented.

► The increase in the load capacity of reinforced beams is significant, amounting to as much as 79%.
► The strengthening is acceptable from the point of view of conservation doctrine.
► The use of CFRP strips is an effective way of strengthening historic beams.