The most critical aspect of the design is the presence of an active landslide at viaduct 2bis, where the erosive action of the Reno river has soon caused gravitational movements. In order to verify its state of activity and to determine its depth and speed of movement, inclinometric pipes have been installed during the additional geognostic survey (the monitoring lasted approx. 1 year, and it continued during the entire construction phase). The designed stabilization included reinforcement works, surface and deep drainage (3 well drains and relevant draining system) and a bank protection made of boulder-size stones. A post operam monitoring was also implemented to check effectiveness of the work performed.
The longitudinal development of the route, in line with the criteria of the Final Design for Integrated Contract, is approx. 5.30 km (2.40 km viaduct, 0.50 km artificial tunnel and 2.40 km open air). The junctions in Grizzana and Marano are also included, which have been rationalized during execution to limit the burdensome and problematic adaptations of existing works, as well as to adapt to the changes of altitude of the route (necessary according to the hydraulic compatibility study performed).
The viaduct piers have indirect well foundations for the piers located in the active bed of the Reno and pile or deep well foundations based on the geomorphic context: the most suitable solution was selected on a case-by-case basis according to in-depth studies on the slope behavior.