ORLY STATION: THE NEW MULTIMODAL STATION

The future station at Orly airport will serve to significantly improve access to the airport by public transport: currently, 80% of passengers arrive by car. It will reroute passengers via the underground (L14, L18), T7 tram, Orlyval, Orlybus, and both mainline and shuttle buses. This dual-purpose 22,500m² station will help develop public transport links. It will feature both a new bus station and a new P0 10-storey car park.

This project is an excellent example of the synergies between the Fayat Foundations Division companies. Sefi-Intrafor (a member of the Demathieu Bard/Sefi-Intrafor Consortium) was involved on 3 structures (P0 multi-storey car park, Orly Station and the F” viaduct), setting up diaphragm walls, grout walls, and tie beams. Franki Fondation (Sefi-Intrafor sub-contractor) handled the piles and micropiles (2 years of works, 6 separate assignments). Works on the micropiles (Franki Fondation) and tie beams (Sefi-Intrafor) are ongoing.

Sefi-Intrafor worked in partnership with Bottes Fondations to install 750 linear metres of diaphragm walls (thickness: 1.5m, depth: 30m), 62 load-bearing elements, 33 integral piers and set up 26 glass-fibre cages to allow the TBMs to pass (lines 14 and 18).

Franki Fondation’s teams were involved in installing 101 piles (diameter: 820 to 1,200mm, depth: 25m) for the foundations of the car park surrounding the station.

And the Support Structures Department teams? They set up approx. 150 micropiles for the foundations of the outdoor car park, multi-storey car park, and station structures between 2019 and 2020.

To date, Sefi-Intrafor’s teams have been hard at work to set up 150 MPD tie beams along the path of the L18 TBM) that will stabilise the diaphragm walls during the works.

Finally, the Trial Boring team organised investigation and core boring campaign as part of the G3 assignment.

N.B. All these works were completed on time, and the diaphragm walls were finished all the way back in June (3 days ahead of schedule). How was this excellent performance possible? Good on-site understanding between the teams from Botte, Sefi-Intrafor, and Demathieu Bard, and highly favourable clay ground. There were no geotechnical “bad surprises”, meaning we were able to keep up a good drilling rate, particularly through greensand, and Pantin and Argenteuil marlstone.

But the teams still encountered a few issues, some major. They could concrete only in the morning, following high demand from Grand Paris worksites, or otherwise had to postpone concreting until the following day. It took 75 staff and three 8-hour shifts a day to keep up the fast pace of one panel per day (including public holidays). The positioning of the integral piers in the load-bearing elements also caused a number of cold sweats. This challenge took not only technical finesse from the on-site teams but also careful preparation. The crane operators had to demonstrate great precision and dexterity to handle the glass-fibre cages safely so as not to warp them. Having to move around the “maze” of Orly airport really complicated both logistics and delivery work. Finally, complex phasing, the frequent simultaneous presence of civil engineering teams from Demathieu Bard on site, and drill mud management were all issues that the teams successfully overcame.

Works on the micropiles (Franki Fondation) and tie beams (Sefi-Intrafor) are ongoing, as the future station’s earthworks station advance.
Work on this site, which began in October 2018, is set to end in April 2020.

Client: Aéroport de Paris
Prime contractor: Systra
Consortium members: Demathieu Bard, Sefi-Intrafor