GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 naves, triforium and clerestory. The analysis of the surviving Medieval structures and of the ancient writen and drawn documentaton supports a reconstructon of the building evoluton. In the second quarter of the 13 th century, probably between 1240 and 1250, the Cathedral underwent major structural changes, recording some of the earliest infuences of the French Gothic in Italy. The damaged structures of the naves were repaired and reinforced through the building of fying butresses (Fig. 1A) that conveyed downward the lateral forces pushing aside the nave walls, while the early overhanging façade was supported by two atached butresses, on both sides of the porch, boastng the Last Judgment sculpture cycle, which is coaeval to the structural modifcaton phase. The 13 th century structural reinforcement was to play a major benefcial role during the numerous following seismic events. Fig. 1 – A reconstructve cross secton of the Ferrara Cathedral afer the 13 th century post-seismic restoraton (drawing by A. Toma and V. Vona), B southern side of the Cathedral, with the main structural lesions induced by foundaton setlement and seismic acceleraton depicted in blue, C the south-eastern corner, with post-seismic collapse transept reconstructon in a backword positon and “wall sewing up restoraton” by reddish bricks, D the Renaissance transect rebuilt at the end of the 15 th century and partally collapsed during the earthquake of 17 Novembre 1570. Late medieval earthquakes . Other earthquakes hit the town in 1285, 1339, and 1346. Near the half of the 14 th century, likely during the 1346 earthquake, the belltower and roof of the San Nicolò Church and many noble family towers collapsed. At the tme, churches were damaged, repaired or rebuilt, as S. Francesco and S. Domenico, but the following transformaton makes the damage recogniton presently impossible. In the early 15 th century, an earthquake sequence afected the town over a 17-month interval, associated with repeated damages in the VII grade MCS range. The sequence started at 9