Royal Mint Gardens
The redevelopment of the Royal Mint Gardens site will take place in two phases. This heavily constrained site, close to the Tower of London and adjacent to Tower Gateway DLR station, is a residential-led, mixed-use development. Phase 1 comprises three interlinked blocks of 15, 14 and 13 storeys, and Phase 2 is a 13-storey building containing 200 apartments.
A deep excavation for the DLR lines arcs through the middle of the site, and a Network Rail viaduct runs along the northern boundary, covering most of the footprint. These major constraints required innovative structural designs to unlock the site, leading to great complexity in the design of both the foundations and the lower levels of the buildings. Approximately 50 % of the site footprint is available for foundations, with the rest inaccessible.
Given air rights over the obstructions, the reinforced concrete buildings will utilise piled foundations placed wherever possible, combined with large-scale beams that span over the DLR encapsulation and a large-scale cantilever system.
Braced steel cores extending to the full height of 13-storey block will be arranged in alignment as close to the viaduct as possible. These will provide support for cantilever trusses which extend out 15 m to either side, bridging over the existing railway, acting as a balanced system. Approximately 15 × 50 m of the building, ten storeys tall, is supported in airspace over the railway lines.
The buildings will be isolated from ground-borne vibration using elastomeric bearings. The entire concept for the design has been conceived around minimising the interface with the live railways and the need for track possessions.
Two courtyards will be situated at level three between the three blocks of Phase 1. These, in combination with new public spaces and communal roof terraces, contribute to the success of the vibrant scheme.
Heavily constrained multi-phased development over active railway lines, requiring transfers and cantilevers
£ 100 million