In 1963, after an unsuccessful competition in 1961, the Municipality of Verona entrusted the design of the new bridge over the Adige to Nervi, who accepted on the condition that he would only deal with the executive design and artistic direction. However, the contract, which saw Nervi & Bartoli lose to a company offering a greater discount, was not awarded until 1966. The bridge was completed in 1968.
Nervi proposed a structural solution with a continuous beam with a variable cross-section, inspired by the bridge with three lowered arches upstream. It is a widely used scheme in Italy, because it maintains a formal analogy with traditional arched bridges, while from a static point of view it allows slimmer sections. In order to achieve maximum economy of material, the beam is structured as a cellular box girder with ribs of varying thickness.
A significant element of the design, which completes its formal expression, is the variation of the section from a trapezoid shape at the supports to an inverted trapezoid in the span.
The width of the compressed zone is therefore always greater than the stretched zone, adapting to the alternation of bending moments that compress the lower fibres at the supports and the upper fibres in the span.
The side walls of the beam consequently assume the geometric configuration of a hyperbolic paraboloid. This ribbed surface with double curvature recurs frequently in Nervi's work because of its intrinsic appropriateness to the construction by means of formwork made of rectilinear strips arranged according to one of the families of generating straight lines.
The resulting undeniable plastic effect is therefore motivated by functional, rather than purely formal, considerations.
Compared to Riccardo Morandi, in whose bridges technological innovation remains more concealed within structures with essential forms, for the Verona bridge Nervi identifies the answers to structural problems in the formal solution, making everything clearly legible.
