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48 Leicester Square, London W1

Client : Linseed
Value : 3.95 M

Overview

PCSA Duraton: 23 weeks

Works Duration: 38 weeks

Existing Structure & Location:

For many years 48 Leicester Square has been an iconic island site landmark which dominates the western side of the prestigious Leicester Square in London’s West End.

The Square experiences some 240,000 visitors on a daily basis and is world renown for its events and film festivals.

Our challenge for this project was to safely deliver an extremely complex demolition project incorporating a four side external façade retention scheme in this densely populated environment.

Scope of Works

  • We carried out an R&D survey and remove all asbestos materials within the existing building.
  • Formulation of over 300 investigation holes into the existing façade to establish connection details.
  • Jacked and load tested the existing floor structures, which proved to be vital as the building had been developed and expanded significantly since 1923.
  • The formation of a shaft within the existing structure to erect a 320B luffing jib Tower Crane.
  • Designed and erected a cantilevered scaffold system enabling the advanced demolition of the existing roof structure.
  • Construction of 3 temporary UKPN substation bases to allow the existing subs to be decommissioned.
  • Building of kentledge bases to support 5 façade Towers, one of which was designed to incorporate the foundations for a new UKPN substation.
  • The design and erection of the external four sided structural steel façade retention system, which was over 180 linear meters in length, supporting five floors of Portland Stone.
  • Careful demolition of the top 5 floors of the structure down to the retained façade level, with all demolition works undertaken within the cantilevered high level scaffolding.
  • Demolition of all internal floor structures within the confines of the existing façade, ‘making good’ of façade fabric and installing weather protection.
  • Whilst the high level demolition works progressed, our concrete cutting teams worked within the existing basement with floor saws and remote Brokk machines, to remove all existing foundation structures within the proposed secant pile line.
  • Specialist automatic core rigs drilled through the existing concrete and steel grillage foundations to a depth of 3m to create a totally clear piling zone.
  • When the demolition process reached basement level, our larger machines removed all remaining foundations and laid a 6F2 pilling mat.

Comments

  • The retention system itself comprised of 250 tons of fabricated steelwork supported on 400m3 of Kentledge,
  • Works were carried out with minimal disruption to local businesses and visitors to Leicester Square.
  • Demolition works were nominated and shortlisted for the 2015 Construction News Awards.
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