Following Venice’s flooding in November 4, 1966, the Italian Government launched a €19 Bn. Master Plan of Measures to safeguard the lagoon and its artistic and cultural heritage from natural disasters. A key part of this plan was represented by the famous MOSE Project, (Experimental Electromechanical Module), an integrated flood proof system engineered to protect the city of Venice from high tides and other extreme natural phenomena.
The MOSE System: how does it work?
The flood protection system consists of 4 rows of mobile gates (for a total of 78 gates) installed at the Lido, Malamocco and Chioggia inlets. These barriers are made of box-shaped metal structures (20m wide, of variable thickness and length) and lie on the seabed in concrete housings. In the event of a high tide the system empties the gates, normally full of water, by injecting compressed air. This causes the gates to rise up and stop the tide. Barriers and concrete housings are connected by steel hinges, technological heart of the system, which allow the gates to rotate around the axis and emerge above the water.
A troublesome history
An ambitious project on paper, that doesn’t work as intended when put into practice. In this regard, several analyses were conducted with concerning implications: first of all there is a very serious discrepancy between the type of steel used during testing (super duplex stainless steel produced by the Italian company Valbruna steelworks) and the one used later in actual manufacture of the hinges, with completely different chemical composition and of uncertain origin.
Based on the project, the estimated life of the hinges would amount to 100 years, however numerous evidences have been presented that show how extraordinary maintenance interventions would be necessary in order to prevent malfunctions.
As if this is not enough, the steel tube that crosses all the underwater housings in the Malamocco inlet appears to present obvious signs of corrosion, preventing the proper functioning of the pneumatic system.
In addition to the numerous design flaws, the MOSE Project has also had a troublesome judicial history over the years, made of alleged and confirmed cases of corruption and bribes further delaying its completion and increasing its costs.
Consorzio Venezia Nuova, in charge of the works on behalf of the Ministry of Infrastructure and Transport – Venice Water Authority, has announced that the project is set to be finished by the end of 2021.
in the night between Monday 2 and Tuesday 3 December 2019, the MOSE floodgates were finally subjected to a first general test, which ended with a success (much to the surprise of everyone). The trial took place from 9 pm to Midnight with the help of Venice’s Harbour Office, who restricted navigation in the area, to ensure complete safety of the workers. According to the technical staff of Consorzio Venezia Nuova, the barriers seem to hold up the swell pretty well.
After the relentless high waters of November, the success of this first test was of great importance, as it marks a first step in the right direction towards the completion of this great work.
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