A new higher-strength grade of weathering steel, bringing structural and environmental benefits, has been successfully installed for the Carrington Bridge project in what is thought to be a UK first.
The 2.5km long highway project includes the first UK bridge to use high strength 'S460W' weathering steel.
COWI, a leading international engineering consulting group, celebrated the successful installation of the steelwork, which enabled its design team to reduce the total material quantity by 15%. The steelwork was fabricated and installed by Cleveland Bridge.
The reduced quantity reduces associated carbon emissions, while the use of corrosion-resistant weathering steel means the steelwork does not require painting, a further environmental benefit.
The use of weathering steel also made it easier to transport and lift the girders, which were delivered to site in segments of up to 48m, then spliced into whole-span lengths of 80m before being lifted onto their supports by a 1200-tonne mobile crane, one of the UK’s largest.
The final two crane lifts over the River Severn were achieved at a radius of 80m, with the crane boom extended to its maximum length of 180m.
Andy Sloan, managing director and senior vice president for COWI in the UK, said: 'We are delighted to have completed the installation of the steelwork for the bridge in less than two weeks. The site has been challenging with regular flooding being an issue and steep slopes which have given us reduced access for construction works, but our team have tackled these problems head on, and we are thrilled with the outcome.'
COWI won the work on the project with Alun Griffiths Contractors Ltd to design the three-span composite road bridge, as well as the geotechnical design of the road embankment, retaining walls and slope stabilisation measures.
The bridge has a total length of 205m and forms part of the Worcester Southern Link Road project, which will convert the A4440 from single to dual carriageway, relieving traffic congestion in the area.
The link road project was costed at £62m last year. Worcestershire County Council is contributing £7.5m to the scheme, with the remaining cash coming from the Large Local Majors Fund.
It includes another significant viaduct as well as a landmark footbridge, also designed by COWI. In addition to designing the structures, COWI was also responsible for all of the geotechnical design of the project, including earthworks.
Completion of the bridge is planned for spring 2021.
