Ville de Lancy
- Start of the works: November 2014
- Duration of the civil works and earthworks: 18 months
Atelier d'architecture Brodbeck-Roulet SA
The objective of this project was the construction of a community centre with underground parking (218 places), and a civil protection shelter (500 places) over two basement levels.
- The project was constructed between an existing cut-and-cover motorway tunnel and an existing local road.
- An existing tramway passed above the basement and was operational throughout the construction.
Excavation in two stages to allow the temporary diversion of the tramway.
- During the first phase of the works, the tramway ran to the north of the project. Diaphragm walls and piles were installed from ground level to allow the street-level slab to be cast. This allowed the tramway to be diverted onto the new slab.
- During the second phase of the works, the basement was completed using a top-down construction sequence through a moling hole in the street level slab. This enabled the tramway to remain operational, mitigating the inconveniences which are typically experienced during basement excavation.
- Top-down excavation of 25,000m3 below the street level slab, on which the tramway operated throughout.
- Excavation dimensions: 80 m x 40 m.
- Excavation depth: 7m.
Diaphragm walls and basement columns
- Diaphragm walls: 240 m long, 80 cm thick, 20 m deep, (area of the walls: 4 800 m2).
- Installation of 70 concrete basement columns from the street level slab (30m length and 1 to 1.2m in diameter).
- Geotechnical surveying programme including pollution monitoring.
- Feasibility studies including alternative options.
- Scheme design.
- Detailed design.
- Tender documentation, comparison of offers, adjudication proposal.
- Construction design.
- Construction phase.