STIB aims to fully electrify its bus fleet by 2035. Beyond the replacement of vehicles, this project significantly impacts the infrastructure of bus depots. After the electrification of the Marly depot, the Jacques Brel and Petite Île depots are next in line for transformation. Work at the Brel depot is scheduled to begin in the first half of 2026, while that of Petite Île is planned for 2027. One of the main challenges of the Brel project lies in keeping the site operational throughout the works. A maximum of 20 buses can be relocated at a time, which will inevitably affect the project timeline.
A complex project requiring significant electrical power
Located between the municipalities of Anderlecht and Molenbeek, the depot spans 50,000 m² and houses 169 buses, including 11 articulated ones. Electrifying the site therefore represents not only a complex electrical distribution project but also one requiring a very high electrical capacity—16 MVA—to charge buses equipped with 450 kWh batteries. To achieve this, 74 chargers of 180 kW and two chargers of 450 kW will be installed. The power supply will come from STIB’s high-voltage grid and will be adjusted based on demand using an intelligent energy management system. Two substations will be built, each housing four 2 MVA dry transformers. Power will be delivered to each bus parking bay’s charging cap via overhead gantries. Electrical distribution will be done using large-section cables, which presents a major challenge in terms of installation, space, and weight. This solution was chosen after analyzing several scenarios to best meet the project’s requirements.
Special attention was paid to the supporting components of the charging caps. At the client’s request, greisch’s steel structure experts designed a custom piece to increase flexibility: the angle of the caps can be adjusted, and their position shifted both vertically and horizontally.
Preserving existing structures
Most of the buses are sheltered under canopies. These structures, made of steel columns and roofing composed of sheet metal and polycarbonate panels, offer weather protection and user comfort. During the study phase, greisch proposed to preserve and raise the existing structures to make space for the new bus charging systems. This reuse of structures avoids the emission of 150,000 tons equivalent CO₂—the equivalent of 470,000 km traveled by a diesel bus (as estimated using the TOTEM software).
The raising of the canopies will be carried out in several phases. After removing the polycarbonate panels, the top sections of the masts will be cut and extended with new column sections. The entire span will then be disassembled—by unbolting the central tube at the column joint and the purlins at the expansion joint—then lifted and reassembled. The additional substructure supporting the charging caps can then be installed. The existing columns, originally oversized, can be reused without modification. To ensure the stability of the final structure, calculations and simulations were carried out using the FineLg software, developed by Greisch in partnership with the University of Liège (ULg), which recently celebrated its 50th anniversary.
Reinforcing site safety
Electric vehicles require enhanced fire protection. Due to the site’s layout—buses are parked in a fan-shaped arrangement—fire can spread quickly. To counter this, the hydrant network will be completely upgraded so that a fire hydrant is available within 100 meters of any point in the depot. Fire-resistant partitions will divide the depot into zones of around twenty buses, significantly improving safety.
One complexity of the project lies in the mixed configuration of the site: metro trains are parked underneath the bus depot. As a result, foundations for the partitions were ruled out. These fire-resistant partitions, made of a load-bearing steel structure and fireproof cellular concrete panels, will be installed without foundations. Extending one meter above the height of the buses, they are exposed to high wind loads and will therefore be stabilized using a counterweight system.
Safety will also be reinforced through improved lighting. As the depot is considered a work area rather than just a parking lot, it requires higher lighting levels than usual. To meet this need, the entire lighting system will be redesigned. 130 lighting poles will be added, and a smart lighting management system will be implemented to ensure maximum flexibility.
- Client: STIB
- Architect: Canevas
- Engineering office: Bureau greisch (Building Services, Structural Engineering, Steel Structures)