61-75, Alie Street is a 28 storey residential tower being developed by Barratt East London Developments (BEL) in Aldgate on the edge of the City of London, we successfully tendered and were awarded the contract to deliver the piling, temporary works, bulk excavation, substructure and concrete frame for the development.
Atlantic Contracts commenced our package of works following demolition of the sites pre-existing structure, the first element of works was to install the 400 piles. The piling to the structure was to include 180 contiguous piles to form a perimeter piled wall to the basement, and 220 bearing piles to provide support to the buildings foundations. All piling operations were to be conducted from aground level piling mat, the contiguous and bearing piling operations were conducted concurrently to gain programme efficiencies.
Following completion of the contiguous piling a concrete capping beam was installed, this cap-ping beam required temporary propping whilst the basement was excavated and large diameter flying shores were installed prior to excavation. The biggest of which was 30m long and weighed 20 tonnes. Following excavation of the basement box which required removal of 8000m³ of material, the buildings foundations commenced.
The building’s basement/substructure consisted of a concrete box, a basement slab on piled foundations, with concrete liner walls to the contiguous piled walls and concrete intermediate suspended slabs up to ground floor level.
Once ground floor was reached the concrete framed superstructure was commenced, the concrete frame consisted of 225mm traditionally reinforced slabs. The floor plate design and that of the tower was of an elliptical shape, with 3 concrete cores containing the stair and lift shafts.
As the tower was 28 storeys high, the need to protect the immediate vicinity below from potential construction activity was paramount. For this reason Atlantic Contracts deployed the use of our new perimeter protection screen system, having been successfully used on similar high rise residential towers. The system would be placed on the full perimeter of the tower, and would be progressively pulled up and in line with construction of the concrete frame.