The paper is divided in three parts. In the first part the history of the domes and their realisation are U~{fbS3,
shortly presented: the Pantheon, Hagia Sophia, St. Mary of the Flower in Florence, St. Peter in *n9t~t6GHg
Rome. so[i"ZM)
In the second part the behaviour of Hagia Sophia is analysed through its history, the observation of pfd||Z
the present damage and mathematical models. The study shows how the dome collapsed several {}F?eI
times in its history. P%#WeQ+
The third part shows the collapse of two vaults of the Basilica of St. Francis of Assisi hit by a strong 1J$sIY,Ou
earthquake on 26 September, 1997. aXi5~,Ks_
The mathematical model and photographic records explain the mechanism of collapse. Finally the OVr,
{[r
reinforcements have been achieved using composite materials with aramidic fibers to strengthen the TR2X' `:O
deformed existing vaults.
