Stone bridges – history and heritage of masonry arch bridges in Ireland
15 November 2016
A new edition of Irish Stone Bridges examines the histories and contexts for Irish masonry arch bridges from 1000 to 1830, examining both their beauty and technical achievements. Read on to learn more and for your chance to win a copy
Ennisnag Bridge - one of the oldest bridges in Ireland
There are about 25,000 masonry arch bridges in Ireland with spans exceeding two metres. These were built over a period of nearly 900 years, though the majority would have been built in the period 1775 to 1900.
Due to their number and ubiquity, it is essential that those responsible for maintaining our roads, railways and canals have a good understanding of the nature of these bridges, including their construction, materials and typology.
A good knowledge of bridges is also essential for those involved in heritage and conservation, as well as local historians, while individual bridges can also be of great interest to those who live in the locality.
The need for a treatise to examine stone bridges in Ireland was met in 1991 with the publication by the Irish Academic Press of Irish Stone Bridges – History and Heritage. This was written by Peter O’Keeffe and Tom Simington, both of whom were retired engineers with many years’ experience working on bridges in local authorities, private practice and government agencies.
The book that they produced was the first major nationwide study of masonry arch bridges, drawing on earlier works such as Ted Ruddock’s Arch Bridges and their Builders (1979), Michael Barry’s Across Deep Waters (1985) and a wide variety of other sources. More than that, though, it involved an intense study of the history and typology of stone bridges in Ireland, with a substantial amount of original research and analysis, leading to a greater understanding of the subject.
Analysis of masonry arch bridges
The book was set out in two parts, the first of which set out the analysis of masonry arch bridges, including their numbers, early types and bridge laws. Their description of the system under which the grand juries built and maintained bridges from the 17th to the 19th centuries is one of the best descriptions of these bodies published to date and is useful for understanding their entire works, not just bridges.
Other sections of the book looked at bridges as shown on maps and the effects of drainage and inland navigation, fortifications and mills on bridges. Greater detail was given in sections that described the mortars used, the nature of stone bridges, bridge characteristics and masonry arch design. All of this was combined with ample use of examples.
One peculiarity of the book, given its subject matter as defined by the title, was the inclusion of a detailed chapter on timber bridges, in particular those built by Lemuel Cox in the 1790s. This is not a complaint; the chapter may be out of place in a strict sense, but it is very useful.
The second part of Irish Stone Bridges, which occupies well over twice the space taken up by the first part, is a series of articles on particular bridges. This was in 75 sections, though in reality it looked at a far greater number, as some of these were groups of bridges, such as the Kilkenny bridges, which examined the bridges built on the Barrow and the Nore in the aftermath of a major flood that destroyed many bridges on those rivers in the 1760s.
A section on bridges in Northern Ireland included four bridges and the section on Kanturk examined two. Furthermore, the sections on individual bridges often carry a significant amount of information about other bridges, so the total number addressed in full or in part was probably closer to two hundred.
Peter O’Keeffe and Tom Simington’s volume quickly became the definitive book on masonry arch bridges in Ireland and repeatedly proved its worth in local authority offices, engineering consultancies, university libraries, local history studies and many other spheres. Sadly, it went out of print, though this did not diminish its utility or its popularity.
Other books on bridges have appeared since and each holds its own niche, but none of them attempted to displace Irish Stone Bridges as the detailed and essential work. As a result, the volume became difficult to find and any that did emerge onto the market were offered at substantial prices, often in bookshops outside Ireland.
Re-examination of all extant bridges
The Irish Academic Press made the decision to publish a new edition of Irish Stone Bridges following the offer of sponsorship from Dublin City Council, and with the support of former city engineer Michael Phillips in particular, and the present writer was subsequently engaged to revise and edit the second edition as, unfortunately, neither of the original authors is still with us.
Preparation of the new edition involved visits to virtually every extant bridge that is detailed in the book to re-examine them, take measurements where relevant and to photograph them, as the new work was to be produced in colour. As a result, there are around 200 colour photographs in the new edition, while diagrams and black-and-white images from the original edition are included again.
Some additional historic photographs in black and white have been included, notably one of Castlemaine Bridge in Co Kerry, which was demolished in 1963 and Lemuel Cox’s timber bridge over the Suir in Waterford.
The approach adopted in the new edition was to retain the original text, though with some updating and correction of errors, as appropriate. Where more recent researches or discoveries had provided new understanding of a bridge, the text was altered or expanded to incorporate the new findings.
The editor’s background in historical geography led to a reappraisal of the chapter on ‘Maps showing bridges’, expanding the section on the Down Survey maps to include more detail on the parish and barony maps and their availability, while also adding material on the pre-Ordnance Survey maps of counties and how they show bridges.
A curious omission from the first edition was any mention of skew bridges and this arose from the focus of the work, which was predominantly on road bridges. The advent of canals and railways made it necessary to use skew bridges (see Grand Canal Quay image, above right) and this is of particular relevance in this country, as the use of rifle vaulting was pioneered on the Kildare Canal Company’s branch canal to Naas in the 1780s, by its engineer, William Chapman.
A section on skew bridges has been introduced into the new edition of Irish Stone Bridges and, in part two, a new section has been added to examine the bridges at the Dublin end of the Dublin and Kingstown Railway, which were the first nine railway bridges built in this country and all of which are skew bridges. As they all cross roads at different angles, they illustrate the different methods adopted when a railway needs to cross over a road at an angle other than a right angle.
A few additions have been made to part two. These include Ennisnag Bridge, on the King’s River in Kilkenny, identified by Dermot O’Dwyer and Ron Cox as possibly one of the oldest bridges in the country (see main featured image). The nearby Kells Bridge (see right) has been included because of its unusual and picturesque approach to widening in the 18th century, while Derrainy Bridge, in Co Clare, has early features and is a substantial bridge on a very minor road.
Each of the entries in part two has been reconsidered in the light of further research and also of visits to the sites. For the entry on Slane Bridge, work by the editor on the refurbishment in 2011-12 has led to reappraisal of the widening of the bridge and the effects of the Boyne Navigation on the bridge.
Most intriguingly, the entry for the Old Bridge at Clonmel has been revisited in some detail, inspired by the text of the first edition, which postulated that original medieval arches might be present under the road in the millrace culverts. When working on the Clonmel Flood Relief Scheme in the winter of 2010-11, the editor had the opportunity to explore the millrace culverts before they were sealed off from the river and this revealed the presence of a medieval pointed segmental arch in one of the culverts.
Irish Stone Bridges is far from being an inventory of masonry arch bridges in Ireland – less than one per cent of the 25,000 bridges are mentioned, let alone described in detail. What it presents, however, is a discourse on the history, construction and style of stone bridges, illustrated by an examination of a representative sample.
Masonry arch bridges are no longer built, but they remain as an important collection that reflects one aspect of the contribution of engineers to our heritage.
Author: Rob Goodbody is an historic-building consultant and has worked extensively on industrial heritage, including bridges.
The new revised edition of Irish Stone Bridges – History and Heritage is published by Irish Academic Press, 438pp; ISBN: 978-1-911024-14-9 (written by Peter O’Keeffe and Tom Simington; revised by Rob Goodbody). To win a copy, email firstname.lastname@example.org on or before Tuesday, 22 November with the answer to the following question: Which bridge is thought to be one of the oldest in the country?http://www.engineersjournal.ie/2016/11/15/stone-bridges-history-and-heritage-of-masonry-arch-bridges-in-ireland/http://www.engineersjournal.ie/wp-content/uploads/2016/11/Ennisnag-masonry-arch-bridge-1024x580.jpghttp://www.engineersjournal.ie/wp-content/uploads/2016/11/Ennisnag-masonry-arch-bridge-300x300.jpgCivilbridges,masonry,structures and construction,Tipperary