As one of BAA’s first-tier integrated suppliers, Mott MacDonald has been the design engineer for all the
£4.3 billion project’s sub-structures and foundations.

We’ve been responsible for development, co-ordination and design of all substructures including the multilevel basements beneath the main terminal, concourse A and B, over and outside roads and all geotechnical design associated with the close proximity of underground tunnels. Other substructures we’ve worked on include taxiway bridges for aircraft over airside roads, concrete underground structures for the track transit and baggage systems as well as underground service tunnels and airside roads.

Among the tasks undertaken is the 1.7km long Piccadilly Line extension, which connects into the existing Piccadilly Line near the central terminal area. Similarly, the Heathrow Express Extension takes the Heathrow Express rail link from the existing rail station at the central terminal area
to the new rail station located beneath the new terminal building.