The design and build contract of a 4.5km access road, just off the A41, to a new waste to energy plant built on a landfill site at Calvert. The road follows the line of a former railway track, incorporating 3 road bridges across it.
Works to the road bridges involved the upgrading of 2 existing structures and the design and construction of a third new bridge.
Severe weather conditions initially held up the works due to the sheer volumes of rainwater having to be pumped off the road surface. To prevent flooding, 450m attenuation tanks were installed, with hydrosliders used to regulate the release of water to just 2lts per second into the existing watercourse.
Lengthy traffic diversions were removed early after the key bridge works were finished ahead of schedule, with repairs to a former overhead railway bridge completed in just 18 wks – four weeks ahead of schedule.
During the early design stages Value engineering workshops were held to discuss various ideas, including maintaining the existing railway ballast in lieu of excavation and raising the overall road levels, amending the capping and surfacing specification and the drainage layouts. The redundant railway structures were examined for reuse into the project with two of the overbridges being retained. The underbridge was redesigned to allow for the HB loading but this was incorporated into the temporary works.
The overall value engineering saved over £1.5m i.e. 18% of the contract value.