Structural design work began in 1996, after the passing of the brilliant British structural engineer Peter Rice, Renzo Piano's friend and consultant, who bequeathed an idea, a concept, that was difficult to transform into a completed work.
Making this undertaking even more challenging was the seismicity of the site, which imposed higher safety conditions than a normal design.
Through initial computer analyses of three-dimensional models simulating structural behavior under all loading conditions, including the effect of high intensity earthquakes, it was possible to ensure that the work was truly executable.
From the initial stages, the design included a double order of stone arches arranged every ten degrees, according to radial lines converging at a fixed point. This design choice, in addition to characterizing the construction geometry of the entire complex, inevitably pushed to cross new frontiers in the use of the material deputed to the construction of the arches. In fact, the almost parabolic shape and the variable section of the arches are not the result of aesthetic choices, but are necessary expedients to better distribute the load of the roof over the arches and ensure their safety.
The arches, which support the roof, reach spans of 45 m and heights of up to 16 m.
They are made of Apricena, a very compact limestone quarried at great depths in nearby quarries in the town of the same name. The stone ashlars, in series of five or six pieces, have been assembled into maxi ashlars, mounted with interposition of mortar reinforced by stainless steel fibers and connected internally with powerful prestressing cables, capable of counteracting any energy of seismic events.