Keltbray Group were appointed by the Client Crown Estate for the demolition, facade retention and piling works at the W4 site immediately behind Regents Street in London.
Keltbray Piling were employed to design and construct rotary bored bearing and Continuous Flight Auger (CFA) hard/firm retaining wall piles. The original scheme showed 1800mm diameter piles around the perimeter which Keltbray value engineered to be pairs of 600mm, 750mm & 900mm diameter.
Piles were designed in accordance with Eurocode 7.
Bearing Piling works commenced with the use of an R312 rig in June 2012 with all works undertaken from existing basement level. The site was typical of inner city London being logistically challenging with all deliveries and spoil removal taking place via an access ramp.
Pile installation took place in a defined sequence, adjacent to controlled demolition activities allowing Keltbray to offer the Client significant programme saving as opposed to more traditional procurement methods.
A CM50 piling rig was mobilised to install the 600mm diameter CFA secant box, with piles supporting vertical and additional horizontal loads from the adjacent grade 1 listed vaults. The secant piles were installed to a verticality tolerance of 1:75 with the wall alignment adjusted to suit the boundary conditions around the site.
Within the area of the listed vaults, 450mm diameter mini piling works were completed based on the use of a Klemm 709 piling rig. Concrete for these piles was lifted across site by the Tower Crane involving detailed, daily co-ordination between ourselves and all parties on site.
The successful piling works were completed on programme.
- Client : Mace
- Location : London
- Value : £1.1m