Disegni e documenti per l’architettura in ferro e vetro in Lombardia. La struttura irrealizzata di Antonio Tagliaferri per la «gran cupola» del palazzo della Loggia di Brescia (1873-1878)

The paper investigates the unrealized plan of the architect from Brescia, Antonio Tagliaferri, for the new roof of the Renaissance Palazzo della Loggia in Brescia (1873-1878) in the broader restoration and enlargement.project of the whole civic palace. On the basis of the design drawings, already known and unpublished as well, and the documents available today, the article deepens the structural and the technological solutions of the innovative, grand metal pavilion vault equipped with a central glazed skylight proposed by Tagliaferri. In particular, the paper examines his audacious and very up to date design that, reproducing the presumed original shape of the wooden Renaissance vault, foresees a huge Polonceau iron structure with exposed intrados from inside the building.