Pre-modern antiseismic presidia in L’Aquila. Wooden elements and construction techniques in historic building

The anti-seismic systems of pre-modern building represent a field of anticipation of the official technical culture expressed in journalism history and are the result of a constructive culture linked to the observation of damage, the intuitive interpretation of the seismic response and the possible countermeasures experimentation. The earthquake of 2009 has brought to light the different anti-seismic measures put in place over the centuries, in the aftermath of repeated earthquakes that hit the city of L'Aquila, In particular, there are numerous wooden elements which, with different functions, are inserted inside the constructive apparatus, both in the basic building and in the aristocratic building, taking sometime the character of a system and more often that of punctual intervention used for single building elements. This is the case of the wooden roots inside the masonry embedded with the function of wooden chains, improvement of the scarves near the masonry hammers and corners or correction of irregular masonry; similar wooden elements can be found into the structure of the masonry vaults with the role of countering the thrust and improve the box-like behaviour of the walls. The use of additional wooden elements is the key feature of the design concepts of the roofing, in the staked trusses and box-shaped roofs, while wooden structures characterize the light cane vaults. In order to the preservation of material and constructive values of historical building, the objective of the study is to understand, through a critical analysis the role of these particular presidia and to evaluate, according to an approach that reassesses the “rule of art”, the compatibility of the intervention modes used.