Union Chain Bridge Project
With a single span of 449 ft (137 metres), the crossing over the River Tweed between Horncliffe in Northumberland and Fishwick in Berwickshire was the longest wrought iron suspension bridge in the world when it opened in 1820. The Union Chain Bridge has stood majestically spanning the River Tweed for 200 years. While the bridge has been maintained, for the purposes of providing a public access route, it needs urgent repair and conservation.
Captain Samuel Brown’s Union Chain Bridge has had engineers describe its design, and that of others, as a ‘web of iron,’ conjuring an image of a spider throwing its delicate, glimmering threads across a valley. It ‘unites’ England with Scotland and, completed in 1820, is fast approaching its 200th birthday. Spencer Group has been appointed by Northumberland County Council to dismantle the bridge and carry out a complete refurbishment and rebuild to mark its bicentenary.
To dismantle the bridge, the contractor must install a civil engineering ‘ski lift’ that will allow rope access contractors to work from above the bridge to carefully dismantle it prior to the bridge being transported for repair. There is no access for cranes to operate and lift, so this was the only way possible. The ski lift access platform will be on both sides and will have foundations that will support the piers and abutments for the ‘ski lift’. These are founded on Ischebeck Titan 73/53 bars at 21m in depth installed by Pennine Geotechnics. The scheme will involve a complete dismantle, refurbishment and re-install over 53 a week period.