Post-strengthening of timber structures with CFRP's

Upgrading structures for higher working loads or restoring original design strength is an engineering task for structures of any material. A great number of existing buildings need specific interventions on site to restore the damages for renovation, including reinforcement or repair of timber structures due to previous overloading, insect and fungal attack. This article presents a study of reinforcement techniques for restoration and strengthening of existing timber floors under bending loads. Structural adhesives for application on the building site are used and the removal of the overhanging part of the structure as well as the inserted ceiling was not necessary. Commercial adhesives were tested. The tests showed the arrangement of the reinforcement and the stiffness of the materials transmitting the loads, i.e. wood, CFRP and the bonding agent, were of decisive influence for the overall strength of the specimen. The results obtained depend on the wood structure and the presence of defects e.g. knots and cracks. The investigations are currently going on and will be supplemented by using further practice related conditions.