Project Description

Abbey Pynford’s Basement Engineering Division has successfully altered a temporary works design package at a Grosvenor Estate project to reduce the risks, costs and duration of the basement construction.

The project in Knightsbridge requires the demolition of an existing heavily reinforced concrete slab and the installation of a 4.1m deep basement below a mews property.

In order to achieve the demanding programme, Abbey Pynford Basement Engineering Specialists adapted the original temporary works scheme. This reduced the number of piles from 20 to 4 and entirely omitted an extensive temporary propping and needle beam arrangement.

Construction Phase Highlights

Specialist diamond drilling and track sawing works were completed to isolate a 1.2m thick existing reinforced concrete slab from the foundations of the property.

A miniature mechanical breaker was mobilised to site and used to break up the existing reinforced slab into manhandle able pieces using a remote operative. This technique reduced the obvious risks involved in the demolition process.

The original scheme to support the existing reinforced concrete structure whilst installing a new basement constituted 20no. piles with needle beams, cross braces and further lateral supports for the underpinning.

Abbey Pynford designed and installed a temporary works scheme to support the same structures with 4no. bespoke mini-piles and two temporary horizontal props.

Abbey Pynford’s restricted access piling equipment enabled mobilisation to site along a narrow mews and avoided the need for a crane lift. The specially developed machinery also enabled the installation of bespoke piles in restricted head room within the existing property.

Whilst maintaining productivity for the main basement works Abbey Pynford was also employed to support an existing barrel vault beneath the main road. Abbey Pynford’s temporary works design team created a scheme that was cost effective and allowed the site operatives to remove the existing two way spanning wall and install a new steel ring beam. The vertical and horizontal supports were installed to temporarily resist the pressure from the earth and traffic above the old vaults.