The stone bridges design: from old treatises to new numerical methods

This paper deals with the rules to design the masonry arch elements and, in particular, it takes into account those ones useful to analyse the late 18th century stone bridges in Campania. A lot of space is given to the “practical rules” stated by the Neapolitan Engineer Vincenzo Lamberti (1740-1790), but we do not neglect, however, to compare them with those found in other contemporary works, which were widespread in the Neapolitan cultural environments. With reference to another paper dealing with typology and building methods of Roman bridges and bridges from the 17th to the first half of the 19th century in southern Italy, we analyse, here, some arch bridges in detail, in order to verify not only to what extent new rules are set into building tradition inherited by Romans, but also their validity in the light of the present knowledge. To this purpose, thanks to an original software, the limit load and the “collapse mechanism” of the chosen examples are calculated, modelling the masonry arch by means of no-tension rigid blocks and neglecting mortar contribution