Opposite the Musée du Quai Branly, along the Seine, a Franki drilling machine competed in terms of elegance with the Eiffel Tower from July to December 2017 on the site of the "Pont de l'Alma" RER C station. Though the station is closed for a period of approximately 18 months, this is part of the Île-de-France public transport accessibility master plan, with the aim of making Parisian public transport networks accessible. Franki built 2 secant pile walls on the Quai Branly side and the foundations of the structures, and Sefi-Intrafor will add the grouted slugs on site.
On this site, the aim is to make the station accessible to Persons with Reduced Mobility (PRM): setup of automatic doors in the passenger building, installation of a specially-adapted ticket office, compliance work on stairs, signs and lighting, upgrading of passenger building access ramp to meet accessibility standards, creation of 2 lifts, extension of platforms by lifts, partial raising of platforms, creation of 2 emergency exits, creation of wider ticket barriers for every platform... All this work requires ground reinforcing and retention, on a small site between the rails, the platforms and the Seine!
After installation mid-July, Franki's teams began with the emergency exit A secant pile wall: 83 piles (diameter: 1,080mm, length: 20 metres), including 42 grouted and 41 reinforced concrete. The wall on the ticket office side was then built: 35 piles, including 18 grouted and 17 reinforced concrete.
Since the start of December, the 49 structural piles, with diameters ranging from 720 to 820 mm and lengths from 20 to 24 metres, have been under construction.
Finally, at the start of 2018, the teams will start installing around twenty piles and approximately forty micropiles in the 3 zones.
Sefi-Intrafor will then take over for the grouted plugs near emergency exits A and B and entrance A, as well as contact grouting between the secant pile wall and the existing structures.
The aim of this grouting work is to reduce the permeability of the ground to prevent water seepage from the neighbouring Seine during earthworks inside the walls (built by Razel-Bec). The borings represent more than 6,420lm and the grouted plugs will be 3 to 4 metres thick.
Consortium: Razel-Bec / Franki (with Sefi-Intrafor) / SMB / Desormaux