The Diplomatic Hall of the Royal Palace of Naples: structural identification of the roofing timber structures by ND tests.

Especially in monumental buildings the preservation is compulsory for perpetuating the history of the construction technologies and of the past used materials. Therefore, the evaluation of the residual bearing capacity of existing structures is necessary, in order to detect any structural deficiency and to select proper restoration interventions. First of all a comprehensive knowledge of the structures should be acquired through in depth surveys, aiming at the structural identification. In this context, the paper exemplifies the structural identification procedure with reference to the complex covering timber structure of the Diplomatic Hall of the Royal Palace of Naples. The focus is specially on the in situ investigation phase, as the first essential step prior to the structural analysis of stress and deformation. Both geometrical and visual surveys are presented, in addition to in situ ND tests, the latter being performed by the CNR IVALSA Institute according to the current Italian Rules. As a result, the geometrical and static schemes were identified, the wooden species distinguished, the moisture content assessed, defects and degradations due to both aging and biological attacks detected, the effective transversal section determined and the effectiveness of the connections evaluated.