Chapelfield Retail And Residential Development - Norwich.

Contract Details.
Client: May Gurney
Project Start date: Dec 2002
Project Completion:2005
Overall project value: over £275m

Background.
This project is part of the £275m regeneration plan to provide retail and residential space on the old Nestlé factory site in Norwich City Centre. When finished in 2005 it is expected to provide 2000 new jobs and will make Norwich a retail centre to rival Cambridge and Peterborough.

The development required the construction of an extensive 12m deep basement, supported by multi-propped contiguous pile walls involving the construction of around 2000 piles.

Ground Conditions.

Made Ground and superficial Norwich Crag sands overlie very weak chalk. Solution features are present within the chalk.

Raison Foster Associates Brief.

Raison Foster Associates provided general geotechnical support and design services for the design of the capping beams, two sections of wall for the 12m deep basement and the steel reinforcement for the large diameter foundation piles. Raison Foster worked alongside the client's geotechnical engineers to provide additional back up and resources.

The capping beams were typically 1250mm wide x 1000mm deep, although the capping beam sections were quite complex to satisfy the layout of floor slabs, columns, internal beams, external walls, access ramps and services. Their design was based on loading details and outline drawings from the Structural Engineer and pile layout proposals from the client. The basement walls consisted mainly of 750mm and 900mm diameter contiguous piles.

One section of the basement wall formed the abutment walls to a proposed highway bridge. This required 1050mm diameter piles up to 24m deep.