Recent studies on the structural integrity and preservation of San Michele Bridge (1889, Italy)

San Michele Bridge (1889), also known as Paderno d’Adda Bridge, constitutes a true landmark of Italian industrial archaeology and is currently a candidate for insertion in the UNESCO World Heritage List, alongside with a few similar bridges in Europe. After over 136 years since construction, this historic iron viaduct remains in service, still forming a key transportation link in the Lombardia region by supporting both railway and road traffic across the Adda river, one of Italy’s major rivers. Owned by the Italian railway network (RFI), the bridge connects the provinces of Lecco and Bergamo in one of the country’s most industrialized and populated areas. Its strategic importance has ensured ongoing use, prompting an extraordinary maintenance campaign by the owner between 2018 and 2020. These efforts, implemented with care, preserved both structure’s architectural integrity and immersion into a beautiful surrounding landscape. The restoration shall not only has extended the viaduct’s lifespan but also preserved its original functional role. This paper is meant to provide an overview on framework studies delivered in collaboration with the infrastructure owner, aimed at supporting the preservation process of the bridge. Collectively, these efforts shall aim at fostering long-term safety, functionality, and heritage value of San Michele Bridge, reiterating its monumental significance, as an exceptional example of nineteenth-century engineering and architectural ingenuity.