From Realtà Mapei International n° 82 - 11/16/2020
The Genoa-San Giorgio Bridge, inaugurated on 3rd August, has replaced the Morandi Bridge, which collapsed on 14th August, 2018.
Reconstruction of the bridge, designed by Renzo Piano and built by Webuild and Fincantieri Infrastructure, was completed in just two years, with the aim of making it a national model for the redevelopment of Italian infrastructures.
Mapei took part in this imposing work of civil engineering by supplying numerous products, including admixtures for the ready-mixed reinforced concrete to construct the piles, and as a consultancy service through the company’s engineers and specialists, who were available round-the-clock from the very start of the project right up to placement of the last pour of concrete.
CHARACTERISTICS OF THE NEW BRIDGE
Compared with the Morandi Bridge, which was 1,182 m long, the Genoa-San Giorgio Bridge, at 1,067 m, is slightly shorter. Also, the new bridge does not follow exactly the same route and has been built around 20 m to the south of the old one. This decision was taken in order to shorten the schedule of works for its construction and to reduce any interference with the buildings below the bridge to a minimum.
The bridge is made up of a steel and concrete deck and a continuous truss divided into 19 spans (14 spans of 50 m, 3 spans of 100 m, 1 of 40.9 m and 1 of 26.27 m), with the whole structure supported by 18 reinforced concrete piles - 7 more than the Morandi Bridge - with an elliptical section measuring 4 m by 9.5 m.
The viaduct has a curved section (overall height 4.8 m in the middle) made from a structure of steel and concrete. The total width of the road section has been increased from the previous 18 m to 30.8 m and there are two 3.75 m wide lanes running in each direction, separated by a 2.6 m wide central reservation.
Each of the two carriageways also has an emergency lane, which the old bridge didn’t have, and there is a 2.5 m high anti-wind and safety barrier running along both sides of the bridge.
Made from glass to mitigate the bridge’s visual impact and provide an uninterrupted view of the surroundings while travelling over the bridge, the barrier is also bird-friendly thanks to a series of special markings on the surface of the glass.
Construction of the piles.
Mapei’s Admixtures for Concrete Division was involved in the project 24/7, with each day split into three 8-hour shifts. Work was carried out incessantly to ensure technical support was constantly available at the three production plants producing the concrete in Chiaravagna, Genoa Harbour and San Quirico, owned by Calcestruzzi SpA, a division of Italcementi.