Assessment of Deformability and Collapse Load of Timber Structures Built According to Treatises of the First Half of Nineteenth Century: the Case of the Truss Structures on the Roof of the Town Hall in Ravenna

Assessment of Deformability and Collapse Load of Timber Structures Built According to Treatises of the First Half of Nineteenth Century: the Case of the Truss Structures on the Roof of the Town Hall in Ravenna Conservation work is not only the action taken to prevent the building decay but, also, expresses the necessity to transmit to the future the ancient construction systems, which can be considered one of the main cultural heritage. Conservation work is multi-disciplinary and involves many skills which contribute to a reasonable project, which has the aim at recognising the importance and the vulnerability of timber structures. As the Charter adopted in 1999 states, the most important intent of conservation is to preserve the authenticity and integrity of the historical, structural or decorative, elements. This necessity requires a very deep knowledge to guarantee, in case of interventions on structures, their conservation and their load bearing capacity. For all these structures, it is necessary to investigate each element, and the weakness and the strength inherent each the structural design. The modern methodology should be: the study of the different phases of construction of complex buildings; the check up of the decay of the material and its causes; the analyses of the deterioration of the structural system and its agents. The instruments for the investigations are: the historical research, the study of the project of each phase of construction, the geometrical survey, the direct inspection with specific methodologies and instruments promoted