The Gravagna viaduct is a work with more than fifty years of life, conceived in a historical period when Italian engineering was experimenting with new, increasingly daring construction models, some of which have shown various improvable characteristics over time; moreover, the works were originally designed to support traffic volumes that were significantly lower than those of today.

Currently the viaduct, despite the interventions carried out over time, does not fully meet the requirements of the NTC 2018 with respect to seismic stresses and in static terms it is, thanks to the ‘struts’ that support it from below, in an operational condition according to the recent ‘Bridges Guidelines’, i.e. with a need for adaptation in a time frame of between 5 and 30 years.

As part of the ongoing process of modernising the motorway under management, work will begin in September 2023.

The grandeur and particularity of the work require the use of explosives to demolish the metal support arches and the need to dismantle the decks concio by concio in the reverse order in which they were built, and then proceed to rebuild them one by one. The work requires continuous and prolonged track changes for each of the two decks.