Other projects and innovations on T5 - a snapshot.
Construction of the £50M T5 spur road from the M25 is under way by Balfour Beatty for the Highways Agency and BAA. Completion by December 2005 of the spur is timed to coincide with the fit-out of the new terminal when the numbers of construction personnel travelling to the site is at its peak.
Consultant Atkins has been involved with road access to T5 from the very earliest days of the project. The T5 Spur Road provides a free flow connection with the M25 and includes major multi-span structures over the M25 and the River Colne. The connecting roads interact with Junction 14 slip roads and were designed to provide single merge/diverge arrangements with the M25, explains Atkins project director Colin Munz.
At Junction 14, drivers on the M25 need only make a single decision whether or not to leave the motorway. Once the decision to leave is made, a further decision is required on the slip road depending on whether Junction 14 or T5 is the next destination.
To the east, the Spur Road crosses 6m deep landfill sites, and it was important to minimise disturbance or removal of the landfill. The ground improvement solution was therefore to support the Spur Road embankment on stone columns.
The earthworks design includes extensive clay capping of the site, gas trenches and monitoring, and controlled dewatering with any groundwater egress treated on site before discharge to watercourses.
The drainage design includes balancing ponds, pollution control measures and use of reed bed technology all developed in close consultation with the Environment Agency, which proposes to monitor the site over future years.
The Spur Road crosses the River Colne via a 70m two span steel and concrete composite bridge architecturally designed by Atkins to mitigate the impact on the Colne Valley.