IL SANTUARIO DI SANTA MARIA DELLE GRAZIE DI FORNÒ: RILIEVI STATICI E DEL DEGRADO E ANALISI STRUTTURALI AGLI ELEMENTI FINITI

The Sanctuary of Santa Maria delle Grazie di Fornò, located in the Forlì countryside, is a unicum for size and shape as a building dedicated to Marian worship. It was constructed between 1450 and the early years of the sixteenth century. The Sanctuary externally consists of a circular masonry structure 15 m high and 33 m in diameter, with four semi-circular niches protruding to the outside; inside, a similar circular structure 20 meters high delimits a central area, covered by an octagonal dome. The space between the two circular structures is covered with a wooden roof resting on thirty-six main wooden beams. The current appearance is the result of changes and transformations that have occurred over time both for static necessities (stresses of the original annular vault) and changes related to epoch's style (the four semicircular niches realized in 1686), as well as for natural disasters (several historical earthquakes) and war damage (the demolition of the bell tower and part of the adjacent monastery in WWII). In-depth inquiries have been made on the building and its surroundings that have allowed an adequate assessment of the current conditions of degradation and damage, both for finishes and for structures. The curvilinear type of all masonry walls has motivated the study of the current structural capacities. Recently an entire laser survey was carried out, providing comprehensive measurements for reconstructing the Sanctuary’s shape and overall size. After the laser survey, several structural analyses are executed, in particular under the foreseeable seismic action with the application of the Guidelines (2011) for the "Assessment and reduction of seismic risk of cultural heritage with regarding to the technical standards for construction in DM 14/01/2008 ". Lately it will possible to study the effect of the possible consolidation works.