The industrial metal structural system in modern architecture in Rome. The projects of Raffaele Canevari

The essay explores the construction innovations resulting from the introduction of industrial metal profiles in Rome's buildings during the late 19th century, through the analysis of Raffaele Canevari's projects. From the 1870s, Rome began to modernize its construction techniques and building sites, although later than the rest of Europe and Italy. Cast iron, iron, and steel structures formed the skeleton of numerous new buildings. However, in the new Italian capital, metal structures were not accepted by society and were systematically concealed behind massive stone and terracotta cladding with traditional forms. This study aims to enhance current knowledge of modern Roman construction techniques by analyzing the executive drawings of Canevari's projects. Raffaele Canevari, internationally trained engineer, applied his expertise acquired in the field of metal infrastructures (bridges and railways) to building works for the young Italian state. The projects designed by Canevari (preserved in the Archivio Centrale dello Stato, Archivio Capitolino and Biblioteca Storica Ministero delle Finanze in Rome) represent some of the earliest examples of incorporating metal frames within the load-bearing systems of Roman architecture. Among Canevari most advanced works are the Palazzo delle Finanze (1871-1879), the Agricultural and Geological Museum (1879-1883), and the retaining walls along the Tiber River (1875-1926). In the first building, Canevari was initially compelled to seal the metal structure behind an external envelope of continuous masonry, plaster, and stucco, and later reduced its implementation during the construction phase to certain areas of the building. In the second building, Canevari showcased metal profiles on the facade and proposed innovative technological solutions, including a cornice composed of two profiled iron beams connected by a series of through joints and containing a compressed wall portion. The architectures designed by Canevari can be considered among the most advanced and daring examples produced in Roman architecture at the end of the 19th century, serving as models for other engineers. The study analyzed a substantial corpus of archival documents, uncovering the project phases, organizational structure, construction site logistics, building techniques and structural materials employed. The comparison between historical publications, recent literature, and the structural systems specified in the project offers further insights into the structural properties of the widely used steels of the time in Rome, although still little known today.