Masonry vaults in Genoa: from historical and archaeological analyses to scientific interpretation of the rules for their construction

Over one hundred masonry vault structures have been studied by means of archaeological analysis, most of them are dated XVII – XVIII century. About one hundred and fifty design instructions have been examined, they were found in the building specifications and tenders since the end of Middle Ages. A global framework was obtained, illustrating the design and building techniques within this region and time period. These two data sources are quite different one from the other; the analysis results were similar and comparable for some points of view, but they also complete each other or suggested new investigations in their respective fields. The result outcome includes data on materials (most of all masonry), textures, geometric shapes, solutions for thrusts balancing, various contrivances and tricks used in the installation phase, historical nomenclature. Some of the building rules adopted by ancient masons are examined in the light of modern scientific culture and technology, evaluating validity and effectiveness. Special attention is made for frequent usage of extrados chains “a braga”, of perimetric reinforcements with tie-rods, extrados “ribs” in the impost zone.