It is one of the world’s oldest suspension bridges, but now it can be seen as never before.
Bridge maintenance, repair and renovation specialist Spencer Group has removed the entire timber decking of the 200-year-old Union Chain Bridge, which links England and Scotland, as part of an essential programme of works to preserve the iconic structure.
The bridge, which has a single span of 449ft (137m) crossing the River Tweed from Horncliffe in Northumberland to Fishwick in Berwickshire, was the longest wrought iron suspension bridge in the world when it opened in 1820.
Credited with being a catalyst for bridge innovation, the Union Chain Bridge is a Grade I listed structure in England and a Grade A listed structure in Scotland and, before these works, remained the world’s oldest suspension bridge still carrying traffic.
Spencer Group has been appointed by Northumberland County Council to dismantle the bridge and carry out a complete refurbishment and rebuild.
The Spencer Group team has now removed the 700 sq m of timber bridge decking using a bespoke overhead cable crane and access platform, meaning it did not have to work from beneath the bridge on the River Tweed. Had it done so, the project would have been delayed by recent high tides.
Joe DiMauro, Project Manager for Spencer Group, said: “The development of systems to enable our operatives to work above the bridge, rather than below it from the water, was a key feature of our submission in the tender process.
“It has proved to have been an excellent move, as we would otherwise have now been behind schedule due to the recent high tides.”
A key element of the project is a commitment to ensure all modifications are in keeping with the historical significance of the bridge, including restoring, rather than replacing, the suspension chains where possible.
The old decking will be replaced using timber sustainably sourced from managed woodland while the existing masonry towers are being restored using sandstone from the same Hutton Quarry as used originally.
Having removed all of the decking, Spencer Group engineers are now using access cradles to begin to remove the 800 cast iron chain pins, 444 chain rods and 170 wrought iron hangers, as well as the 31 tonnes of wrought iron suspension chains.
A blasting and painting facility has been established on site, where all elements will be cleaned and restored to their original strength, wherever possible. Every link and chain that can be repaired will be specifically returned to its original place.
Once the bridge is completely down, Spencer Group will fully remove and replace the original English and Scottish anchorages. This will involve working from a bespoke steel access tower on the English side and deep excavations on the Scottish side.
It will also remodel the English and Scottish approach roads to incorporate parking for visitors to the bridge, which is used by both vehicles and pedestrians and is a popular tourist attraction.
Spencer Group’s specialist bridges team has been working in close collaboration with Northumberland County Council, Scottish Borders Council, Museums Northumberland and community group Friends of the Union Chain Bridge on the project, which has been partially funded by the National Lottery Heritage Fund (NLHF).
The funding was secured amid concerns the bridge may have had to go into managed decline.
Robert Hunter, Chair of the Friends of the Union Chain Bridge group, which formed in 2014 and has more than 700 members, said: “The bridge hasn’t been seen like this before, certainly not in living memory, and it’s a quite remarkable sight.
“It’s a great relief to us that the bridge is being restored, as we could have been witnessing it being dismantled for good.
“This is an incredibly significant moment in the rich history of the Union Chain Bridge and Spencer Group have been absolutely brilliant.
“Their expertise is extraordinary and they couldn’t have done more to keep us all informed and up to date, including sending us regular newsletters about the project. They have been faultless.”
Mr DiMauro added: “It’s a real honour for us to be carrying out such an important project, which will safeguard the future of one of the world’s most historic and iconic bridges.
“We fully appreciate the significance of the Union Chain Bridge and we know just how much it is valued and appreciated.
“We will be bringing the bridge back as good as new, while retaining many of the original elements and without changing its appearance.”
The full restoration of the bridge is on schedule to be completed by January 2022, with drivers currently being re-directed by a short diversion.
The Union Chain Bridge had only been accessible to one vehicle at a time due to its restricted width and had a weight restriction of two tonnes. The weight restriction will be increased to three tonnes following the rebuild.