13 May 2020
sponsored by Unibail-Rodamco-Westfield
*** Winner! ***
Balfour Beatty (BB) is constructing a new bridge in Ebbsfleet Garden City to improve connectivity and reduce journey times from Springhead Park residential area to the future city centre and Ebbsfleet International station. The 87-metre long bridge provides two-lane vehicle access, pedestrian footpaths and a cycle path.
The project, awarded by Ebbsfleet Development Corporation (EDC), via the Scape National Civil Engineering and Infrastructure framework forms part of a development plan to create a 21st century Garden City in North Kent. The bridge provides a key link from the residential developments in the east to the future city centre and the existing rail station - allowing safe vehicle, cyclist, pedestrian and Fastrack (bus) movements. The route orientation, ecological and archaeological considerations required a collaborative approach with multiple approving authorities and stakeholders.
The land the bridge is being built on has been provided by the developer Countryside Properties and Ebbsfleet Investment GP Limited (EIGP). To facilitate the smooth delivery of the project and aid collaboration, EDC commissioned a bespoke collaboration agreement that both parties signed. The Scape framework simplified the procurement process for EDC and provided them with early access to the civil engineering expertise that Balfour Beatty provides. Other benefits include:
Throughout the project, BB worked closely with the local community. They created work placements, engaged with students from local schools, colleges and universities, and donated topsoil to a local charity to support the creation of a new community garden.
The bridge spans over Ebbsfleet river where there is lots of wildlife. To prevent damage to the ecosystem and ensure disruption to wildlife is minimised, they employed an ecologist to work alongside the project team. With the use of vegetated embankments and gabion baskets, they blended the new structure into the environment. Work has been programmed to avoid impact on the bird nesting season, and prior to construction, a special barrier was installed to prevent reptiles and amphibians from entering the site.
To eliminate unnecessary traffic on an already congested network and the carbon emissions associated with it, BB installed a pontoon access bridge across the river instead. This also removed the need for two welfare setups on either side of the bridge. The pontoon has no environmental impact unlike alternative temporary bridge structures, which require semi-permanent foundations to be constructed and removed.
Large cofferdams were constructed in the watercourse to enable the construction of the foundations without constricting the natural flow of the river. To enable excavation inside the cofferdams, dewatering of the cofferdams was required. This was achieved through pumps and settlement tanks. Pumping water through straw bales after the settlement tanks enabled them to discharge clear water into the watercourse, protecting the local ecology. To stop fish from entering the water pump a fish trap stop was installed.
To minimise the land take on the floodplain, a reinforced earth embankment was constructed at the north side of the river, this provided a natural alternative to reinforced concrete and required less space than a conventional earth embankment, minimising the impact on the river and ecosystem.
About the Civils Project of the Year Award:
The SECBE Awards team look for outstanding local projects that: demonstrate great team working between the client and entire supply chain; were delivered before the programmed completion date, below the approved cost plan and to quality exceeding expectation whilst delivering the highest of health and safety standards; achieved the lowest environmental impacts; delivered outstanding customer satisfaction and may have also received praise from other stakeholders, and demonstrated the highest levels of the application of best practice, innovation and technical achievement to overcome the project’s challenges.