Lot n°1 concerns the main contract for the construction of the interchange n°9. This contract is a works contract in the municipalities of Mont-Saint-Guibert, Ottignies-Louvain-la-Neuve and Chaumont-Gistoux. The purpose of this contract is the redevelopment of existing roads, the rehabilitation of a bridge and the creation of new engineering structures.

Lot n°2 concerns the merlon of the surplus land generated by lot n°1.

Road works include:

• Adaptation of the ramps of the existing interchange (E411 (A4) N°9 – Corroy-le-Grand);

• The adaptation of the N25a between this interchange and the N4/N25 axis, which includes the widening of this road, the integration of concrete dividers and the redevelopment of the intersection with Rue Granbonpré to facilitate access to the zoning;

• The separation of local traffic from motorway flows between Rue de Chastre and Rue Granbonpré;

• The creation of the diamond interchange and its new access ramps, including the civil engineering part (CV, sheathing, post reservations, etc.) of the traffic lights.

• The creation of a carpool car park accessible from the N25a;

• The creation of secure cycle links separated from the road, on the one hand within the diamond interchange and on the other hand along the N25a;

• The realization of landscaping along all roads by means of trees, various plantations, grassed areas, transition embankments, etc.;

• The integration of comprehensive stormwater management, including a new sewer system for new roads and infiltrating ditches at some shoulders.

Work on engineering structures includes:

• The rehabilitation of the existing bridge over the E411 motorway;

• The creation of a pertuis under the N25a and an exit hopper to allow the flow from Brussels (E411) to access the N25 directly without crossing;

• The creation of 2 ovoid bridges, whose architectural aspect has been highlighted, at the diamond interchange (junction N4 / N25) to allow the passage of elevation of the east-west axis.

The work includes, among other things:

- The installation of signage for BAU closure

- Clearing, with or without extraction, with or without evacuation, of the area concerned

- Removal and handing over of arable land

- The construction of a track to allow the pouring of land

- The profile of the merlon

- The construction of ditches and the raising of existing visiting rooms

- Plantations and other sodding.