Rhône Canal Modernization, Sète, FR | 2012

The transformational project for sustainable waterway transportation

The Rhône Canal in Sète extends over 65 km, connecting the port of Sète to the Rhône via the small Rhône at the Saint Gilles lock, currently allowing the traffic of boats up to 1,000 tonnes. Significant modernization works on the canal began in September 2010. The main objectives of this vast project initiated by "Voies Navigables de France" are to improve the canal's characteristics to develop river transport between the port of Sète and the Rhône-Saône waterway axis. These works, which extend until 2018, are carried out in partnership with the Languedoc-Roussillon region for an investment of 100 million euros.

This ambitious project from an economic point of view is also significant from an environmental perspective. Indeed, the canal travels through sensitive areas along its route that must be preserved during the works: the Hérault coastal ponds, the wetlands of the Camargue gardoise, and classified sites.

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fr French AMCRPS_CS-016_Aresquiers_FR.pdf
Coupe type de la zone de croisement
canal du Rhône
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The works related to the Aresquiers crossing zone began in October 2011 for a duration of approximately 16 months. The verticalization of the banks will locally widen the navigation rectangle to 34 meters from the canal ceiling over a length of 650 meters on the left bank and 540 meters on the right bank. The transit of larger commercial boats will increase from the current 900/1000 tons to 2300/2500 tons.
The presence of a hard layer (limestone and marl) at a shallow depth (approximately -8 m NGF) directed the choice of the type of bank support towards a combined wall solution. The support wall is made from steel tubes and 3 intermediate PU 10R steel sheet piles. The tubes are the main elements of the mixed wall, they take up the horizontal forces corresponding to the soil pressure and hydrostatic pressure as well as the vertical loads of the structures.

To ensure a lifespan of 50 years for the structure, the sheet piles are coated on one side and their entire length with an ACQPA anticorrosion paint system of type Im2A NI 631. The tubes are protected by this paint system over a length of 5 meters. After the wall is trimmed, a reinforced concrete coping beam is created at the top of the wall.

To better integrate this element into the protected environment (a classified site), a bush-hammered concrete finish was implemented. Cast steel bollards and elastomer fenders will complete the structure. Throughout the construction period, canal traffic is maintained. The works were interrupted on April 1st, 2012, to ensure the tranquility of the colony of heritage coastal birds for whom this area is the main nesting site. They resumed on July 31st, 2012.