Bridge Street, Cardiff

Bridge Street is centred around a 27-storey 80m high tower, with an 11-storey wing to the rear elevation and two 5-storey wings on the front elevation. There is ground floor retail space on either side of the central tower and the retail provision will incorporate retained historic buildings.

Clarkebond were commissioned by Watkin Jones Group to provide detailed design of the building and in addition to addressing the particular challenges associated with the design of tall buildings, i.e. stability and control of building movement under lateral loads, this site had constraints which Clarkebond engineers had to overcome in their designs.

Bridge Street was a brownfield site within a conservation area, constrained by roads on 3 sides and by foundations of adjacent buildings. Particular attention was paid to ensure the sensitive retention of existing historic commercial buildings to be incorporated into the ground floor mixed-use space. Clarkebond also carried out ground investigations for geotechnical and geo-environmental aspects and made recommendations to deal with backfilled basements from previous development on the site.

Key Points, Bridge Street:

  • The superstructure of the building is framed in reinforced concrete. The upper floors are to be concrete slabs supported on reinforced concrete columns. A central reinforced concrete core and outer reinforced concrete walls provide stability under lateral wind loading.
  • Transfer slabs at first floor level eliminate street level and prior development complexity and constraints on column and wall positions and provide for a regular column grid and increased floor area for the tower and accommodation wings, maximising the development opportunity.
  • Flat slab construction is adopted for the floors, minimising storey height and maximising the number of storeys achievable within planning constraints.
  • Continuous flight auger piles are used to counter significant inflow of water encountered in some boreholes.
  • Structural analysis and design validation was undertaken using a 3D finite element model constructed in the TEKLA Structural Designer software package.