Chelsea Barracks redevelopment, temporary anchoring
Chelsea Barracks was a British Army barracks located in the City of Westminster, London, adjacent to Chelsea and Belgravia, on Chelsea Bridge Road. Today, Chelsea Barracks is owned by Project Blue Ltd and is the flagship London development of Qatari Diar, a subsidiary of the Qatar Investment Authority.
As part of the redevelopment to create around 450 residential units, medical centre, community gardens and shops, Keller UK were sub-contracted to provide temporary anchors to provide propping to an installed secant piled wall, as an alternative to propping and shoring using conventional techniques.
The anchors have a maximum length (a wayleave) such that anchors cannot go past the centerline of Chelsea Bridge Road, and the extents of the Chapel land. The anchors have to be short, hence underreamers were used to develop the load.
Working with Keller UK, to create the optimum design, Colcrete Eurodrill manufactured 12 underreamers, plus drill rods of 114mm diameter, with 3 ½” Reg. tool joints, together with 220mm diameter rope casing for construction of the temporary anchors.
Anchors are founded in the London Clay, and were constructed using Case and Auger (220mm/190mm respectively) techniques. Free length varied up to 15m. Fixed length between 6 to 9m (4 bell / 6 bell respectively). The tendon, headplates and caps consist of a 43mm GEWI plus bar from Dywidag Systems.
Crossrail 2 future development route is approx. 6m beneath the pile toes of the wall.
In all, 196 temporary anchors were installed, and the drilling program was significantly shortened.