Spencer Group completes world’s largest bridge cables anti-corrosion project

Spencer Group, the High-level bridge maintenance specialist, has completed an £8m project that will remain the largest of its kind ever to be undertaken worldwide.

The Hull-based specialist engineering company has successfully delivered the world’s largest retro-fit cable dehumidification project on Denmark’s vast Great Belt crossing.

The 18-month project saw work undertaken to protect the main cables on the East Bridge, the third largest suspension bridge in the world and part of the Great Belt network, linking the eastern and western parts of Denmark.

The Spencer team delivered the project for client, A/S Storebælt, over the spring and summer seasons of 2014 and 2015, with no safety accidents or incidents, despite the challenging conditions, and without any disruption to the bridge’s 31,000 daily vehicle crossings.

Throughout the project, the Spencer team and staff from Danish sub-contractor Davai, which supplies labour for specialist works, walked along the cables to access Spencer’s trademarked Cable Crawler gantries to carry out the dehumidification works or deliver equipment and supplies.

With its towers reaching 254 metres, the East Bridge is almost 100 metres higher than the Humber Bridge, which was the longest suspension bridge in the world when it opened in 1981, while its span of 1.6 kilometres is 15% longer.

Andy Macdonald, Project Manager, said: “Every bridge project has its own unique set of challenges, but this was a major step up and on a different scale from any of those we have previously undertaken.

“Throughout the project we worked very closely and collaboratively with the client, who were highly supportive and understanding of the complexities and challenges involved.”

Mr Macdonald paid tribute to project team for their technical expertise and physical endurance while working in such testing conditions.

He added: “This was a brilliant team effort, which demonstrated the technical capability within the Spencer business and our commitment to deliver a painstaking project to exceptional levels of quality.

“Jobs like this are not for people of a weak disposition. The guys are pretty tough – they have to be! After a few days you just get used to working so high up, with just the bridge deck below you. On a sunny, calm day it was the best place in the world to work. The views were stunning – you could see for miles.”

Weather became a severe issue for the Spencer team, who could not work from the gantries in high winds while, in wet conditions, the wrapping process could not be undertaken, nor could personnel walk on the cables.

However, almost six kilometres of cables on the East Bridge were sealed in an elastomeric wrap known as Cableguard. As each section was wrapped, thermal blankets were used to heat the wrap and create a continuous airtight seal around the main cables before dry air was pumped into the lengths of wrapped cable.

Spencer is now actively pursuing further high-level bridge maintenance projects in the UK and Europe, including dehumidification schemes.

Pete Vessey, Spencer Operations Director, commented: “The successful delivery of this project is a phenomenal achievement, worthy of the unique status it will retain. It required extraordinary technical expertise, innovation, resourcefulness, determination and physical endurance – not to mention a team with a very good head for heights.

“We are very proud to have completed a world-class project and to have ensured a magnificent structure will be a vital part of the transport infrastructure in Denmark for many, many years to come.”

Eight Spencer staff worked in Denmark for the duration of the £8m project, with a 16-strong team from Davai and a Danish sub-contractor Belvent, which provided the dehumidifiers, pipework and injection and exhaust sleeves.

The culmination of the project was a month-long programme of testing to ensure the wrapping had provided an air-tight seal across all the main cables.

Lars Fuhr Pedersen, Technical Director, A/S Storebælt,added: “Spencer Group has delivered a very important piece of work in respect of our ongoing maintenance of the East Bridge and in safeguarding its lifespan of at least 100 years.

“We have enjoyed an excellent working relationship with Spencer because of their diligent and committed approach and the high standard of their work. We also appreciate the importance that Spencer has assigned to safety, which means that the project has been completed with no accidents whatsoever.”

Spencer has used its Cable Crawler gantry system to enable vital dehumidification work to prevent corrosion of cables on the Severn, Forth Road and Humber suspension bridges in the UK, the Alvsborg Bridge in Sweden and now the East Bridge.

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