Restoration and strengthening of timber structures: principles, criteria, and examples

Conservative restoration principles developed for the protection of monuments are currently applied in the structural upgrading of traditional existing buildings in order to preserve their cultural heritage. Timber structures, typically, present in these buildings to support roofs and floors, had for long been substituted when buildings were upgraded, often using new and different materials, and sometimes yielding unsatisfactory results in terms of structural behavior. The current conservation trend requires developing criteria for interventions and implementing operative procedures complying with modern structural safety requirements and satisfying conservative restoration principles. Research progress is also being made in understanding the behavior of traditional timber joints and elements in service conditions and at the limit state under exceptional actions, as well as the effectiveness of different types of reinforcement. Actual cases of restoration of buildings that included conservation of the timber structures have proven to be economically competitive with the choice of substitution.