The paper is divided in three parts. In the first part the history of the domes and their realisation are {3N5Fi7S
shortly presented: the Pantheon, Hagia Sophia, St. Mary of the Flower in Florence, St. Peter in {p7b\=WB-
Rome. k^Uk= )9
In the second part the behaviour of Hagia Sophia is analysed through its history, the observation of e%v0EJ},
the present damage and mathematical models. The study shows how the dome collapsed several c\N-B,m&
times in its history. kg()C%#u
The third part shows the collapse of two vaults of the Basilica of St. Francis of Assisi hit by a strong fR,7l9<%Zp
earthquake on 26 September, 1997. #W[C;f|,
The mathematical model and photographic records explain the mechanism of collapse. Finally the z{G@t0q
reinforcements have been achieved using composite materials with aramidic fibers to strengthen the Ov| Uux
deformed existing vaults.
