Latimer Road Apartment Block, Wokingham

Ground investigations identified Made Ground overlying the Bagshot Formation and London Clay, with ground gas and sulphate conditions also present within the Made Ground. These findings informed the concrete specification, with a DC-2 classification applied to both the raft and piles.

The proximity of the railway was the main design constraint. Network Rail’s Track Support Zone restricted piling activities close to the railway boundary, meaning a uniform pile design could not be used across the building footprint.

Pile lengths and working loads therefore had to be carefully controlled to accommodate the restrictions while meeting the building’s structural requirements.

SPEEDECK designed a single 1,155m² piled raft, constructed at 300mm thick and incorporating two lift pits and movement joints to suit the building layout.

Rather than applying the same pile specification throughout, the design used a zoned piling arrangement. Piles closest to the railway were shorter and designed for lower working loads, with lengths and capacities increasing further from the railway boundary.

Pile lengths typically ranged from 9m to 18m, with maximum safe working loads of approximately 610kN in areas furthest from the railway.

The ground investigation also identified no significant heave risk beneath the building footprint, so void formers were not required. The concrete specification was developed to account for the identified DC-2 classification.

SPEEDECK delivered the piling and reinforced concrete raft as a single, coordinated substructure package over an eight-week programme.

Across most of the site, a lightweight piling rig operated from an uprated concrete blinding layer, providing a concrete working surface without the need for a conventional granular piling mat across the entire footprint. This reduced the requirement for additional aggregate, excavation and muck-away.

Within the railway’s zone of influence, a granular piling platform was retained to meet the relevant Network Rail requirements.

By coordinating the foundation design with the construction methodology, SPEEDECK delivered a solution tailored to the site’s ground conditions, structural requirements and railway restrictions. The completed foundations were handed over ready for the subsequent superstructure works.