A TRAPEZOIDAL PLAN SAIL VAULT BY ANTONIO DA SANGALLO THE ELDER IN THE LIVORNO FORTEZZA VECCHIA: FROM HISTORICAL INVESTIGATIONS TO AN ANALYSIS OF ITS STRUCTURAL BEHAVIOUR

The present contribution aims to illustrate some first results obtained from ongoing research on a 16th-century masonry sail vault in the Fortezza Vecchia (the Old Fortress) in Livorno (Italy). A multidisciplinary research is currently ongoing. The information collected by means of geometric surveys and experimental tests are being used as input data for the different analytical and numerical models expressly developed to study the vault’s structural response. The structural analysis has been performed using two analytical models set within the framework of limit analysis. The first considers the vault as a thin shell, and suitable sets of statically admissible stresses are built; the second model is a modern reinterpretation of Durand-Claye’s method for domes. As an additional term of comparison, numerical analyses are carried out by means of FE models. The study is still under development, and a first set of results has been obtained by limiting the analysis to vertical loads accounting for the self-weight of the vault and that of the overlying soil layers.