The Issy Coeur de Ville district aims to reinvent urban life by offering a lively living place that respects the environment.
The future district will extend right in the city center over more than 100,000 m² articulated around a 13,000 m² wooded park, a new generation of 17,270 m² retail offer with a 7-screen cinema, '' a digital center, with 627 housing units, 25% of which are of a social nature as well as 40,874 m² of offices and public facilities including a school group (10 classes) and a nursery (60 cradles).
It is therefore in the context of a construction site in an urban site, and its space constraints, that Sefi-Intrafor and Franki Fondation have started the foundation work for this large-scale project.
In a first phase, the works consisted for Sefi-Intrafor in the installation, management and earthworks of the site (including a nailed wall, carried out by Franki Foundation, allowing the realization of the diaphragm wall). Being then in almost total possession of the platform, this made it possible, despite the time constraints, to optimize production. The diaphragm wall 800 mm thick and 43 m deep on a rectangular linear 60m by 80m, drilled with a grab, was able, thanks to the efforts of the teams, to be completed one month in advance.
The current phase includes a lowering of the water table, earthworks over a depth of 17 m as well as the simultaneous construction of 292 anchors and the laying of 190 t of struts distributed over 4 beds inside the excavation. This new work leads to internal phasing issues. In addition, the teams must now deal with those from Bouygues who have fully started their work and have taken over responsibility for the site since September. This then means finding solutions to the growing co-activity on the site.
On the Franki Foundation side, teams are mobilized on the execution, using a CFA, of 720 piles with a diameter of 500 to 1,200 mm up to a depth of 30 m, including around one hundred retaining piles for the Lutecan wall.
An exceptional volume for the company which will end with the lift of a CFA machinel inside the diaphragm walls with the aim of making piles at the bottom of the excavation.
The Franki Foundation teams face the same phasing difficulties as their Sefi-Intrafor colleagues and suffer from a large co-activity to be managed on several platforms.
This worksite mobilizes 20 people for Sefi-Intrafor and up to 11 people in 2 workshops for Franki Fondation. In terms of schedule, it began in March 2019 (start of pile work in June) and will end in March 2020.
Client : Cogedim
Site supervisor : Builders and Partners