July 2008 Issue 2

Tendering Winning Design - Rivermead Leisure Centre

The Challenge

At tender stage, our D&B clients asked us to prepare a tender design for the above project. The project is for a leisure centre sat on a former 1970’s landfill site and around 250m from the River Thames. 
The landfill material was around 3.0m deep and sits above river gravels over a major aquifer.
If that was not bad enough, gasses emitting from the site were at characteristic situation 4.

The site investigation called for a piled solution, but the Environment Agency did not want the gravels puncturing with piles as this would allow leachate from the landfill to pollute the aquifer and here lied the dilemma.

The Solution - Foundations

When we looked at the borehole logs and other data, we found that the landfill material was generally granular and well compacted.
After carrying out a quick foundation analysis we put forward a foundation solution to float the building on top of the landfill by using a reinforced ground beam solution with a ground supported slab.
This solution not only gave a large cost saving against piles, but also against conventional pad foundations.

But How Did We Validate our Proposal

We sent out our one of our geotechnical team to site and carried out a series of trial pits, which all confirmed our tender design. Following negotiations with building control and the Environment Agency our design was accepted and our client was appointed the contract.

The Solution – Gas protection

Our original thought was for a passive piped system laid in clean stone. However, following a few phone calls we contacted PAGeotehnical, (www.pageo.co.uk) about their “Low Energy Clean Air Blanket.”  This gave a 50% cost saving over the passive solution, together with other benefits.

Benefits to the End User

Rivermead Leisure will now have an active system with automatic real time monitoring. This will give them a level of confidence that is not available with a passive system and will result in lower insurance costs.
Our D&B client has now won the tender, and are currently on site constructing this building.

For more information contact us on: winmytender@pwaite.co.uk