The first UK bridge to use a higher-strength grade of weathering steel has hit a construction milestone after the steelwork was installed.
Engineering consulting group COWI is working with contractor Alun Griffiths on the construction of the 205m-long Carrington Bridge, which converts the A4440 from single to dual carriageway.
COWI has claimed that the bridge is the first in the UK to use high-strength “S460W” weathering steel. Using this stronger grade of steel enabled the COWI design team to reduce the total material quantity by 15%.
The steelwork does not require painting and the use of less material means that it has been easier to transport and to lift, COWI said. The bridge was delivered in segments of up to 48m, then spliced into whole-span lengths of 80m before being lifted onto their supports by a 1,200-tonne mobile crane. 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.
COWI has designed the three-span composite road bridge, as well as the geotechnical design of the road embankment, retaining walls and slope stabilisation measures. The 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 steelwork for Carrington Bridge was fabricated and installed by Cleveland Bridge.
The 2.5km long highway scheme includes another significant viaduct as well as a 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.
Andy Sloan, managing director and senior vice president, 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.”
Completion of the bridge is planned for spring 2021.
