Three-Dimensional Limit Analysis of the Vicoforte Elliptical Dome

Limit Analysis provides a conceptually simple and robust method to estimate the safety of structures and has been long applied to the analysis of the ultimate collapse state of two-dimensional masonry structures or structural elements. In revolving symmetric domes, the three-dimensional problem can be reduced to the two-dimensional case under appropriate hypotheses. The Vicoforte dome is the largest elliptical dome in the world, and its complex geometry makes this kind of analysis not straightforward. Starting from some basic assumptions, a method for analyzing the three-dimensional elliptical geometry and understand the behavior at collapse of the drum-dome system using limit analysis is proposed. The three dimensional collapse mechanism is found and the system behavior including the presence of tension rings at different levels is interpreted. The results are compared against a nonlinear finite element model.