Linking a housing development in Chelmsford with the A12 trunk road, the Beaulieu Parkway Bridge is a vital piece of infrastructure that alleviates congestion around the Essex town.
Award: Beaulieu Parkway Bridge, Chelmsford
Architect Aecom
Structural engineer Aecom
Steelwork contractor Briton Fabricators
Main contractor Graham
Client Countryside Zest
Constructed over an 18-month period, the Beaulieu Parkway Bridge spans both the Great Eastern Main Line railway and the northbound A12 slip road, providing a connection to the new Chelmsford relief highway, while also creating a route to a planned railway station.
Curved on plan, the steelwork elements for the 161m-long three-span weathering steel bridge consist of four lines of 2.7m-deep plate girders, which have been designed to twist into shape under permanent load.
“Accuracy of fabrication, which was vital to this project, was controlled in the workshop, using laser levels and purpose-made jigs,” explains Briton Fabricators managing director Dean Morcom.
“Information was gleaned from our advanced steel 3D model, which was prepared in-house by one of our experienced design modellers.”
Overall, the steelwork contractor fabricated, supplied and erected 891 tonnes of weathering steel for the bridge.
Confined nature of the site
One of the main challenges was the confined nature of the site and the limited access. Consequently, the plate girders were delivered to site in small sections that were then welded together into 40m-long sections.
To carry out this preliminary work, temporary trestles were designed and deployed to support the girders, while shrouded areas were installed to allow the team to weld, test and blast the steel sections.
Once the paired girders, weighing up to 132 tonnes each, had been made up into the required lengths, they were then lifted above the adjacent overhead railway power lines and transferred onto another temporary works set-up.
This ‘at height’ temporary location mimicked the bridge’s final abutment and its two intermediate central support piers. With two rows of purpose-built trestles positioned at weld locations, all of the structure’s connections were completed.
Once all the preliminary works had been completed, self-propelled moveable transporters (SPMTs) lifted and moved the entire bridge superstructure to its permanent location. The bridge weighed 2,400 tonnes during the installation programme.
The bridge was manoeuvred and cantilevered over the railway line and the A12 slip road, and installed within a 10mm tolerance. This is believed to be the longest bridge installation ever undertaken in the UK using SPMTs.
“This three-span highway bridge has an extraordinary construction story. The structure, which spans a road and live railway, is curved in plan and section. Built on the ground, complete with much of its deck, the structure was then driven into position on multiple SPMTs.”
‘Important strategic link’
Martin Leach, managing director, major projects, at Countryside, says: “We were enormously proud to announce the opening of the new Beaulieu Parkway bridge and relief road for Chelmsford, the final stage of a £35m infrastructure programme which will have such a positive impact on the local community.”
Councillor Lesley Wagland OBE, Essex County Council’s deputy to the leader with principal accountabilities on major infrastructure projects and freeports, says: “The bridge provides an important strategic link for commuters and is intended to help ease congestion around the town as people journey to and from Braintree, Stansted and the M11.
“Essex County Council has worked hard with partners to put in place a number of transport developments in this part of Chelmsford, from the relief road to the new bypass and train station, which are vitally important for making sure the transport network is fit for the future and giving local people safer, greener and healthier choices in how they travel.”
Produced by BCSA and Steel for Life in association with Construction Management
