Mainly built in the 60s and 70s with a strong architectural style which was innovative for the time, the La Part-Dieu district in Lyon became the first business district outside the Greater Paris region. In recent years, the original structures have needed a facelift, including expansion of the SNCF station (which was completely saturated), pedestrianisation and new real-estate projects – all led by the publicly-owned local development company SPL Lyon Part-Dieu.
Soletanche Bachy has been involved in several of these projects in the last two years:
- in 2018, the shopping centre, with piles for its expansion,
- in 2018, the Emergence Lafayette building, with diaphragm walls and piles,
- in 2018, the expansion of the Vivier Merle tunnel, with diaphragm walls and injections,
- in 2019, the station “Voie L” track (eastern side), with piles and anchored lutetian-type walls,
- in 2019, Infragare, with anchors for an existing structure, piles and injections.
All that was left was to launch the district’s flagship renovation project, located just outside the station: an underground space called “Parking Place Basse” (shops, bicycle racks and parking spaces on four levels) and the To-Lyon tower designed by Dominique Perrault (170m high, with a 4-star hotel on eight floors and 43 floors of offices).
Since these two projects are too closely intertwined to be separated, VINCI Immobilier is responsible for completing both structures simultaneously (the underground car park will be subsequently transferred to Lyon Parc Auto).
After many years, which have seen the Soletanche Bachy and VINCI Construction France teams study numerous dimensioning, phasing and constraint scenarios (particularly for SNCF tracks), the works contract was signed by the partners on 1 August 2019.
Soletanche Bachy is responsible, as a VINCI Construction France co-contractor, for retaining structures and foundation works including:
- 17,000m2 of diaphragm walls.
- 67 foundation barrettes for the car park
- 900 micropiles in the lower levelling (15m of borehole + 19m of micropiles)
- 90 Starsol® 1.50m (or 1.20m) piles of 25m for the tower
- 80 cable anchors
- 260m 3 of injection
After a few test micropiles and anchors in September 2019, the equipment (two wall workshops, two micropile drills, one pile drilling machine) will arrive from January 2020 for two years of work in two phases.