London Development Project

Swanton Consulting working with Erith Contractors provided the engineering support and temporary works designs for the demolition of the existing BT Fleet Building and London Evening Standard Plumtree Court Building at London Development Project, located in Farringdon. The former consisting of a seven storey reinforced concrete framed building with a thirteen storey tower and two level basement, and the latter consisting of a nine storey concrete framed structure based around a central courtyard with a single storey basement.

We carried out the design of the supports for two tower cranes, required to support the superstructure demolition for machine and material movement. The first tower crane was supported on a bespoke steel grillage designed and installed around the existing structure, adjacent to a protected BT cable chamber and suspended on the backpropped ground floor slab. The second was resin anchored into the existing raft slab without a grillage, saving further steel cost and time on the programme.

Our works also included designs for the protection and sequencing around the three existing UKPN substations and the BT structures, including a cable chamber, reception rooms and lift shaft to deep level tunnels. This was done with significant constraints imposed by the stakeholders involved, with engineering consultation provided throughout.

For the substructure works, Swanton Consulting proved the capacity of the existing 14m high retaining walls in the Fleet Building to free stand without any temporary works, value engineering some 500t of steel. Within the existing London Evening Standard Plumtree Court Building, A-frames supports were installed to allow the future piling works to take place. This was continued into the high-level Fleet Building area, where the walls were similar thicknesses, with further A-frames provided on top of heavily reinforced blocks to ease their removal during the piling sequence.

The final phase of these works involved excavating a hit-and-miss slot trench around the perimeter of the site through the existing raft slab to allow for the future secant piling works to be undertaken. This was detailed and sequenced by Swanton Consulting to ensure that the installed propping works and existing retaining walls would be unaffected.