The purpose of the Issy Cœur de Ville (i.e., city centre) neighbourhood is to reinvent inner-city life by creating a vibrant, environmentally-friendly living environment.
The future neighbourhood will stand right in the city centre on a >100,000m² site, featuring a 13,000m² leafy park, 17,270m² of next-generation business premises complete with a 7-screen cinema, digital centre, and 627 apartments (25% council housing) as well as 40,874m² of offices and public facilities including a school (10 classes) and nursery (60 cots).
It was on this urban worksite, with space limited, that Sefi-Intrafor and Franki Fondation began work on the foundations of this large-scale project.
For the first phase, Sefi-Intrafor’s role, as head of a consortium featuring Pro-fond, SMTP and Franki Fondation, was to set up and manage the worksite then take on the earthworks (including a soil nail wall built by Franki Fondation to allow the diaphragm wall to be set up). As the consortium was in charge of practically the entire site, production could be optimised despite the tight schedule. The excavator-built diaphragm walls (thickness: 800mm, depth: 43m) forming a 60m x 80m rectangle were successfully completed 1 month ahead of schedule as a result of the teams’ hard work.
The current phase includes groundwater lowering, earthworks (depth: 17m) and the simultaneous setup of 292 tie beams and laying of 190t of struts spread across 4 layers within the groundwork. These new works have caused internal phasing issues. Plus, the teams now also have to work alongside counterparts from Bouygues, which got properly started on their works and took over the site back in September. This has meant we have had to find ways to deal with the increasing number of teams on the site at any one time.
And Franki Fondation? Its teams are busy setting up 720 hollow auger cast piles (diameter: 500 to 1,200mm, depth: up to 30m), including over a hundred retaining piles forming a shotcreted soldier pile wall.
This is an exceptionally high volume for Franki, which will round off by using a crane to lower a drilling machine inside the diaphragm walls to set up piles at the base of the groundwork.
Franki Fondation’s teams encountered the same phasing issues as their Sefi-Intrafor colleagues and were affected by the high number of teams on site at any one time across several platforms.
This worksite featured 20 staff from Sefi-Intrafor and up to 11 staff from Franki Fondation across 2 workshops. How about the schedule? Work began back in March 2019 (start of the piles works: June) and is set to end in March 2020.
On this project, Sefi-Intrafor was both directly contracted to Cogedim and head of the consortium featuring: Pro-fond, Franki Fondation, and SMTP. And Franki Fondation? It was part of a joint venture with Bouygues HAR/CPI to build the structure and sub-contracted by the SMTP consortium to set up support structures.
Assistant to the client: Builders and Partners
Consortium members: Sefi-Intrafor, Pro-fond, Franki Fondation, SMTP