The plaque commemorates the bridge's role in the development of the suspension chainbridge as the first road suspension bridge in the UK and that it has the oldest surviving eye-bar link chains in the world.
British suspension bridge pioneers, like Thomas Telford - the first president of the Institution of Civil Engineers - and Captain Sir Samuel Brown would lose out in the race to be the first to build a road suspension bridge in Britain to Exuperius Pickering, gentleman and ironmaster of Ruabon, Wrexham, who built the first road suspension bridge here at Llantysilio.
Permission to erect this inverted suspension bridge, in which the level deck was supported on iron catenary curve chains below the road deck, was granted in 1814 to span the Dee and was in use in July 1817 enabling Pickering to deliver coal, lime and bar iron by wagon from his wharf on Telford's Llangollen canal to the A5 London to Holyhead road.
In 1870 Pickering's chainbridge was refurbished as a footbridge after suffering flood damage, but was still an inverted chainbridge. It was replaced again in 1929 by Sir Henry Robinson who decided to rebuild the bridge as a conventional suspension footbridge along the lines of the Menai Suspension bridge using the original chains from 1817.
After falling into disrepair and closed for over thirty years, the lead for the refurbishment project in 2015 was taken by Llangollen Town Council supported by Llantysilio Community Council working with Shemec Ltd, funded by the Heritage Lottery funding the majority of the cost along with locally raised funds.
The refurbishment scheme – which won the ICE Wales Cymru Roy Edwards Heritage Award 2016 – included restoring and repairing each iron element and providing a new timber decking and therefore Llantysilio Chain Bridge chains are the oldest surviving eye-bar link chains in the world.
Stephen Lawrence, Chairman of ICE Wales Cymru, unveiling the plaque said:
"The Institution of Civil Engineers commemorates important historical engineering achievements. This plaque commemorates the bicentenary of this unique Chain Bridge which has been through three reconstructions and a major refurbishment in the two centuries since it was opened. Remaining constant, however, are its chains and what we see here today supporting the bridge are the oldest surviving eye-bar link chains in the world."
He continued: "In 1971 ICE established the Panel for Historical Engineering Works. One of the Panel's objectives is to raise the general public's awareness of the great engineers of the past and their work. One of the ways we do this is to place plaques at locations where the public can be made more aware of the history around them.
"In the past twelve years ICE Wales Cymru has placed or supported 26 plaques and information panels throughout Wales - marking important historical engineering sites and commemorating famous engineers such as Trevithick, Brunel and Telford. This is all part of a programme to raise the general public's awareness of our historical engineering heritage and I hope today will go some way in helping to achieve our objective.
"We also unveil plaques and banners at project sites to showcase current civil engineering schemes as part of our 'This is Civil Engineering' campaign and unusually this bridge can be considered a modern scheme as a result of its recent refurbishment as well as a project steeped in history."
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