Of domes and their trap. The long history of the domed structures, between debates and experimentation

The aim of this paper is to show the potentiality of empiricism in identi- fying the real mechanical behavior of ancient masonry domes, definitely stating the solution for their primeval "trap". The mechanical behavior of the domes – their lack of stability due to the horizontal thrusts generated by the arches which compose them – couldn't be mathematically demonstrated by ancient architects but some fundamental historic debates represent as many enhancements in their structural conception. Starting from the two "Mecanicopoioi" of Hagia Sophia, passing through Brunelleschi's terrific inventions, up to the slender design of Sainte Gen- evieve in Paris, this paper analyzes the issue of the "dome's trap" (its in- eradicable horizontal thrusts). The final aim, in an ideal route from the empiricism to the scientific approach, is to clarify the structural behavior of masonry domes, demonstrating the efficacy of the traditional encircling tie-rods intervention.