61 Curzon Street

August 2017 - September 2019 - £4.7M

Professional Team - CBRE/WT Patnership/Watermans/Cantillon

  

The project was located on the corner of Curzon Street/Bolton Street in London’s West End. The area is extremely busy and immediately adjacent to two pedestrian crossings. The building had party walls with two residential properties one of which is grade II listed. There are also commercial offices in close proximity to the front and rear elevations of the site. 


Our team worked with the WCC Environmental and Highways department to agree a Site Environmental Management Plan which contained a section 61 and maintained all pedestrian footpaths and the highway open and largely unrestricted.


As demolition works progressed several challenges arose due to the unknown nature of the existing buildings and our neighbours Party Walls supports, as a result of this our scope increased to include the following works.


  • Demolition of the existing 10 storey steel framed / RC encased building down to ground level, working within the limits of the section 61 agreement with WCC.
  • Scaffold oversailing to two neighbouring boundaries and WCC footpaths whist maintaining pedestrian access to crossings.
  • Design and installation of temporary works to No 63 Curzon street Party Wall as our neighbours property had no external wall. Our design not only protected the exposed 9 storey flank from wind loading it provided a weathertight insulated screen to the environment.
  • Design and installation of the temporary works support tower to provide lateral restraint to No.20 Bolton Street Party Wall. The steelwork tower was designed to be lifted in ahead of the demolition process and support whalers installed as the demolition progressed. All temporary steelwork and foundations were coordinated with the new build construction to cause minimal disruption during construction.
  • Design and installation of a bespoke temporary works system to support to the No 20 Bolton Street Chimney at 3rd floor level. The chimney over sailed onto our property and historically taken support from our structure during construction. All designs also required listed building approval.
  • Obtaining an AIP from WCC for the underpinning and two stage basement temporary works support system.
  • Installation of the site Tower Crane and all associated mini piling / enabling works.
  • Demolition of all structures below ground, removal of existing foundations, pile probing and installation of a stage 1 temporary works scheme in preparation for piling.
  • Installation of 42.no 600mm diameter bored piles 30m deep, 8.no 450mm diameter 30m deep and two king post wall cofferdams for the attenuation tank and lift pit.
  • On completion of the main bored piling works we installed the stage 2 temporary works scheme to the full basement perimeter, the support system was a two level whaler and raking shore system to allow the reduce level dig to progress whilst supporting the highway.
  • The excavation phase was undertaken with the assistance of the site tower crane, mini machines loaded remote control Gecko skips that could safely loaded waiting lorries on the Curzon Street highway. The excavation process continued to create the formation profile which included the attenuation tank, lift pit, stepped slab and pile caps.
  • All piles were cropped, surveyed for location and tested as part of our works, the concrete blinding was laid to levels ready for novation to the Main Contractor.  


Challenges overcome by the team


1. Designing new temporary works solutions at very short notice to overcome existing structure changes.

2. Constant liaison with the WCC highways department to manage deliveries and road closures to 

coordinate with the adjacent ongoing development.

3. Maintaining demolition progress and resequencing works to accommodate all of the site changes in temporary works and scope of works.

4. Working within an extremely confined site environment (270m2) with several trades working simultaneously.