New headquarters of the SNCB at the “Gare du Midi” railway station

The project aims to bring together, on the same site, some 4,000 employees from several departments of the SNCB and its subsidiary HR-Rail, currently spread over separate sites, with the aim of introducing more transversality and collaboration between departments.

The project involves the renovation of three existing buildings and the construction of a new rectangular building on the “Avenue Fonsny’ side of the municipality of Saint-Gilles. This new headquarters extends the existing 30,000 m² to a total area of 75,000 m²

The new building will be built entirely in metallic structure. The main gantries with double overhangs (columns and beams) are made of standardized open H-profiles and the floors are made of steel deck slabs.. This choice presents a perfect coherence with the architecture while respecting the particular conditions of the site. Indeed, this solution is light, prefabricable in the factory and has a very short lead time.

Wind bracings are evenly distributed along the length of the building, guaranteeing optimal wind load recovery. They are materialized by diagonals between gantries, and free the vertical circulation cores from their structural function, which makes the operation of the building very flexible.

Interventions on existing buildings are minimally invasive. The project’s finely studied geometry intelligently takes advantage of existing structures, reducing demolitions to a strict minimum. In building 49, the new building is erected adjacent to the existing one; in building 48, it is based on the existing structure taking advantage of the available load reserve; and in building 47, it penetrates into the existing volume without having to demolish large areas

Interventions in the existing building consist of local reinforcements and the recovery of existing elements to support new loads or new arrangementsThe study of the existing elements allows to adapt the effort diagrams of the existing elements without having to reinforce or replace them.

As far as the foundations are concerned, new pile bases support the new column alignments. Nevertheless, the foundations of the building 48 and some of the building 47, which have a significant reserve capacity, are used to support the loads induced by the new building. When necessary, micro-pile reinforcements are added to the existing foundations to increase their resistance.