PSI - Issue 62

Marco Menegotto et al. / Procedia Structural Integrity 62 (2024) 1014–1019 Menegotto, M.,. Fieno, L., Rocchi, M.C.

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4. Work in progress Maintenance never ends. The numerous interventions as above, for seismic upgrading or replacing whole viaducts, were being implemented after 2009, when the disaster of the Polcevera bridge (2018) here in Genoa shocked public opinion and authorities, who reacted emotionally. This had the double opposite effect of, on one hand, eliciting the survey and safetization at once of all road works in the Country and, on the other hand, delaying the interventions due to stops on technical actions ordered, after glance impressions of immediate danger, by political and judiciary actions, including a revocation of the Concession and of the funding to SdP, being now reassigned after two years but times and costs arose. So, also the company got hit by the emotional wave and risked bankruptcy. This was an odd event, too. Fortunately, its work is now gradually resuming. The situation at present is the following. Referring to the need of structural retrofitting along the whole network, SdP implemented up to now essential and urgent interventions for assuring safety and efficiency of use. Most of them concerned strengthening of prestressed beams, very costly indeed, when applied to structures of the 1960-70s, to make them comply with the recent MIT Guidelines on bridges. As for the seismic upgrading, a programme of immediate safetization (MISU) was set, assigning top priority to viaducts having suffered direct important damage by the L’Aquila earthquake (2009), totalling 26 viaducts. These interventions are now completed, at a cost of ca. € 200 million. As for short-term interventions on other viaducts, they were divided into high and medium priority ; the first related mainly to simply supported beams, the latter to continuous beams. All these, involving 72 viaducts, are in progress, for an estimated cost of € 1 billion. All works above lie in the Region Abruzzi. Those located in the West section of A24 (Rome – Torano), less seismic prone, are left for next future, due also to the intense traffic served, which makes it difficult to intervene on the road itself, whereas building nearby alternative tracks, also widened for meeting higher traffic,c is preferred. The corresponding estimation amounts to € 2 billion. Other alternatives of major layout changes, with long tunnels, are being studied for the future. 5. Conclusive remarks It has been outlined how a company manages the maintenance of a motorway network, taken in charge much later than its construction. Interacting technical, financial, juridical, and operational aspects are to be considered in a holistic vision, which is crucial, to overcome manyfold drawbacks and to keep acting on maintaining in good shape an important infrastructure. Even odd unrelated unpredictable events have dramatically affected the activity of the company in charge pf the Autostrada dei Parchi .