Corrugated Shells: A Reinforced Concrete Roof Designed by Aldo Favini in Sesto S. Giovanni

Aldo Favini, an exponent of the Italian structural school, was entrusted with the design of a fuel station in Sesto S. Giovanni for Aquila s.p.a. company. He envisaged a peculiar structure: a thin cylindrical vault made of reinforced concrete, whose external shape was sinuously corrugated with a thickness within the value of 60 mm. The corrugated roof is supported by a stiff hollow transverse beam, which rests on a V-shaped pillar and a slender column. Unfortunately, this structure has been demolished. The proposed corrugation shows an interesting enhancement “by shape” in structural behaviour since the shape increases the stiffness and the bearing capacity with respect to a plane surface, allowing for such a reduced thickness. Corrugated shells are also known for the iconic dome of the “Palazzetto dello Sport” in the Flaminio district of Rome, whose rim is gently corrugated and provides structural enhancements. This paper aims to give a new gaze to the tradition of shell construction in Italy, where the shape is wisely adapted to improve structural performances efficiently. The development of analytical and numerical methods to analyse such structures is crucial, especially when a safety assessment is required before a refurbishment to avoid disgraceful decisions like the demolition of the “Aquila” fuel station. Furthermore, although nowadays the building of corrugated concrete shells is decreasing, new construction techniques of 3d concrete printing make readily available the realization of sophisticated shapes, where corrugation should be fully included because of their natural predisposition to improve the mechanical behaviour of shape-resistant structures.