Review: Project Iron Bridge - Saving an Industrial Icon
Charles Thomson, EN UK Committee Member, reviews the online lecture held on 22nd July in collaboration with English Heritage.
English Heritage won a Europa Nostra/European Heritage Award this year for its conservation of the Iron Bridge over the river Severn in Shropshire, the world’s first bridge constructed of iron and completed in 1779. The project and its background was described in a webinar on 22 July by Matt Thompson, Head Curator of Collections at English Heritage, which looks after more than 400 properties across England.
In introducing the award, Sneska Quaedlieg-Mihailovic, Secretary General of Europa Nostra, welcomed an audience from all parts of the world and thanked the organisers of the event – the European Commission, the Society for the Protection of Ancient Buildings, and English Heritage. The Secretary General announced that the Bridge will feature on the front cover of the Europa Nostra Laureates 2020 brochure, which can be found here. Sneska stressed the significance of the bridge in its social, economic, cultural and artistic importance, receiving millions of visitors every year. From the beginning it attracted the interest of Italian and Polish nobility, Swedish and German engineers, and industrialists from France. Writers and artists from all over Europe were moved by it. This support continues: a foundation in Germany (Gerda Henkel Stiftung) gave 1 million Euros towards the total project repair cost of 4.3 million Euros. Sneska emphasised the benefits that Europa Nostra awards have on local communities, and towards the commitment and wellbeing of present and future generations.
Sara Crofts, Chair of Europa Nostra UK, introduced Europa Nostra to the audience, and stressed her hope that a number of educational events will take place over the next few months, to foster the exchange of knowledge and ideas, heritage debates and policy making, and encourage the take-up of entries for next year’s awards. The UK is a key player in the awards, with the second highest number of awards winners since the programme was started in 2002.
Matt Thompson then took up the chair to thank the awards panel and said that his main interest was in the representations of industry in art, literature and poetry. The Iron Bridge project was the largest undertaken by English Heritage since it became a charity in 2015. It was a functional piece of physical infrastructure with hundreds of thousands of users, and a toll bridge for vehicles until 1950.
When Abraham Darby I came in 1708, iron ore, limestone and coal were used in the power to blast furnaces, and coke (mineral fuel) to power mining. When his grandson, Abraham Darby III, came in the late 1770s/early 1780s there was a constant flow of traffic on the river and in 1776 an Act of Parliament was passed to allow construction of the bridge, which opened to traffic in 1781.
In 1780 Abraham Darby III commissioned William Williams to paint the bridge, as part of a busy landscape of industries but a leafy, sequestered place, showing a boat with sightseers in the foreground. Abraham was a Quaker and not given to self-exaggeration. but it was ‘not just a bridge, but also a spectacle.’ It was made a World Heritage Site by UNESCO in 1986.
Many surveys of the bridge have been done over the years to show how the influence of traffic has required cracks to be repaired, which had threatened its integrity. Laser scans and complex 3D models have been made of its spatial structure, and surveys have shown that since the late 1990s some 118 cracks have been found – mostly historic, replacing wedges or deck-plates. The condition of the bridge was shown to be surprisingly robust, as was its structural integrity after a major flood in 1795.
In 2017 the whole structure was enveloped with scaffolding, involving aluminium tubes of 30m. length. On completion, this was wrapped in plastic sheeting to protect the bridge and those working on it. The bridge was never closed to the public and the walkways were kept open. A team of volunteers spent time on the bridge speaking to visitors and explaining the complexities of the conservation process, which could be viewed through ‘portholes’.
The main ribs of the bridge were kept in the correct position in relation to the deck structure, and a series of iron wedges (of which 325 needed to be replaced) minimised internal movement. The deck surface of a ‘shade of grey’ was bound by a hardwearing gravel matrix. Each layer of paint exposed to the atmosphere was re-painted in the original red/brown colour scheme (similar to that featured in Williams’ painting) , oil-based to last a minimum of 25 years. Completion in 2019 of the structural repairs will hopefully last for several centuries.