Major retaining structure to facilitate factory extension
Carpenter Limited
ICC Infrastructure Conditions of Contract Measurement Version August 2011


The purpose of the works has been to create an area to accommodate a future factory extension and improve access around the factory.

The site was constrained by a hillside and it required cutting into the slope adjacent to the factory to provide a level platform on which to extend the factory. Ground retention was therefore required along the boundary of the extension to retain the face of the excavation in the permanent case.

 The Works

The works began with site clearance. The removal of vegetation and some fencing, the removal of buried obstructions, decommissioning, and diversion of service, and diversion of a public footpath.

Major earthworks took place with the excavation and disposal of 65,000m³ of rock and other materials, with topsoil reserved on site for reuse in the contract.

A piling mat was constructed for the ground anchor at 10m wide for the entire length of the piling wall. 183 bored cast in place contractor designed contiguous concrete piles were installed, with a reinforced concrete base, waling and capping beams with “Shotcrete” finish to exposed piles,  99 ground anchors, relief wells, drainage and landscaping. A pedestrian handrail / guardrail was placed on the retaining wall capping beam.

The ground beyond the bored pile wall was re-graded to a slope of 1 in 3, reseeded and landscaped.

New fencing, pedestrian and vehicular gates were constructed around the sites with pair of vehicular gates to the Shaw Lane entrance.

Extensive temporary works were also required, which were commissioned from consulting engineers Byrne Looby, a practice with whom we have worked with over many years.

Key Challenges

10 ground anchors failed which could have jeopardised the completion date, however we were ahead of programme due to piling commencing earlier than anticipated and they were removed and reinstated.

The site was very wet and there was an influx of water from uncharted drainage systems, which could have caused problems for the operation of the factory. Good housekeeping, bunding and extra road sweeping kept this under control.


A top level COMAH site, it was a live busy factory with large articulated lorries accessing the rear of the factory adjacent to the working area. There was a daily interface with Carpenter’s senior management and deliveries to the site were planned to accommodate the factory’s requirements.

Civil Engineering / Highways / Structures
Civil Engineering / Highways / Structures
Civil Engineering / Highways / Structures
Civil Engineering / Highways / Structures

Get in Touch

For all enquiries, please get in touch with the team here at Eric Wright.