STATICALLY ADMISSIBLE SHELL INTERNAL FORCES FOR THE STABILITY ANALYSIS OF THE DOME OF PISA CATHEDRAL LOADED BY VERTICAL AND HORIZONTAL LOADS

The present contribution illustrates some recent results concerning the stability anal- ysis of the oval-based pointed masonry dome of the renowned Pisa Cathedral subjected to both vertical and horizontal loads. The study is aimed at determining lower bounds of the horizon- tal collapse load by making use of the static theorem of limit analysis. Heyman’s hypotheses are adopted, i.e., masonry is assumed to have unlimited compressive strength and zero tensile strength while collapse due to sliding is assumed to be prevented. The structural analysis is carried out by modelling the dome as a thin shell; an ad-hoc solution procedure is enforced which is able to define optimised statically admissible stress fields. The results in terms of stress distribution and safety factor are discussed.