20 Farringdon Street

Pile Type: Contiguous & Bearing

Number of Piles: 36no.         

Diameter: 900mm & 1050mm & 1200mm

Depth: 35m

The scheme required the construction of 58no. load bearing and settlement restraint piles of up to 1200mm diameter to be bored to depths of 35m. 

Standard piling rigs with an operating weight of around 50-65 tonnes would usually be required to construct piles of this diameter but the party wall running the length of the site would not allow for a machine of this size to operate owing to the operational ground load being to high.

Martello's MP5001 piling rig was capable of delivering the scheme by constructing 1200mm diameter piles to a depth of 35m with an operating weight of 25tonnes. The compact nature of the equipment enabled Martello to operate on an existing slab at a lower level with an existing 4.0m deep basement with constrained dimensions.

The Martello rig was able to access the basement via a ramo down which bigger machines would been unable to traverse. The pile positions were cut from the existing slab using the diamond drilling technique and the existing slab later incorporated into the new building.

The project was completed in two phases which allowed for the base grouting to take place after phase one piling along the party wall.