On-site consolidation systems of old timber structures

Conservation authorities often specify that original timber structures are maintained as integrally as possible, even when structural upgrading is needed. In the restoration process, when the consolidation of load-bearing parts (e.g. decayed beam heads) or the strengthening of structural sub-systems (e.g. the reinforcement of floors) is necessary, the intervention with glued-in rods is an interesting alternative to the replacement of whole timber elements. Adding reinforcing materials to the existing timber is currently a quick, cheap and well-established practice, but two important issues need to be addressed by the designers: the compatibility between the materials and the reversibility of the intervention. A large effort for the development of improved adhesive-based systems has taken place in Italy over the last 5 years, both in research institutions and in the industry. Among the various initiatives, a highly significant one has been the 3-year "Parnaso" project, co-founded by Mapei SpA and the Ministry of Research, and coordinated by the Wood Research Institute within the National Research Council (IRL-CNR, nowadays IVALSA-CNR). The main activities and the results of the project are summarised in this paper.