Work on the Clonmel Flood Relief Scheme provided the opportunity to explore the millrace culverts of the town’s Old Bridge before they were sealed off from the river, revealing a medieval pointed segmental arch in one of the culverts
Civil

The town of Clonmel in Co Tipperary is believed to have been founded by the de Burgos in the 13th century. From 1338 to 1583, the lands were owned by the earls of Desmond. In Tipperary: History and Society (1985), Bradley states that Bridge Street is mentioned as early as 1388 and the laneway east of it in 1424.

A grant of murage and pontage was given in 1356. The bridge is depicted on the town’s coat of arms, which is similar to that of New Ross, and it should be noted that the bridge on the arms has five arches, not three; perhaps one should say at least five arches, as it may only depict part of a bridge.

The selection of this site for the town in the 13th century was probably influenced by the fact that the river widens here, so that it is shallower and more amenable to being forded. There is a substantial island known as Suir Island and a satellite island called Stretches Island and the walled town was located on the north bank opposite these islands.

The Old Bridge of three arches now connects the town proper with Suir Island and, a little to the south, Suir Island Bridge crosses to Stretches Island. Beyond this again, Green Lane Bridge crosses the southern channel of the river and a (normally) dry channel is crossed by Dry Bridge, completing the crossing to the southern bank.

The bridge is shown on Moll’s map (1714) as part of the principal road leading to Dungarvan and to Cappoquin. The Dungarvan branch is omitted on Petty’s General Map of 1683. The Down Survey map, compiled in 1656, clearly indicates the bridge together with a miniature perspective sketch of the walled town located at its northern extremity.

Important medieval crossing point


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CLICK TO ENLARGE Fig 1: Location of Old Bridge, Clonmel (courtesy of Irish Archaeological Consultancy Ltd)

Mentions of the bridge are scarce, given its importance as a crossing point in the late medieval period on the route leading from Dublin via Leighlinbridge and Kilkenny to the Norman towns of south Munster. The town’s charter, granted by James I in 1608, refers to a ‘bridge long and high’.

Chetwood, in A Tour Through Ireland, gives an informative mention in 1748: ‘There is a very spacious bridge over the Suir just out of the gate to the right, of twenty arches.’ This bridge of twenty arches is mentioned in many gazetteers’ and travellers’ accounts over the next ninety years or so. One of these was Philip Luckome, a Cambridge printer, and (in History of Clonmel, 1907) Burke comments that Luckome had ‘visited Clonmel just before its expansion under the milling industry’.

Some of the descriptions are clearly derivative. Sleater refers (in Topographical and Hibernian Gazetteer, 1806) to ‘Clonmel: four cross streets; bridge of twenty arches over the Suir’, while Hansbrow, in 1835 states that ‘Clonmel consists of four cross streets; it has a bridge of twenty arches over the Suir’. Clearly, information such as this is merely copied from one source to another and an error in the original source would be repeated, or a change in circumstances would be ignored.

The Norman antiquities of Clonmel were discussed in a paper by Lyons (‘Norman Antiquities of Clonmel Burgh’, JRSAI) in 1936. He states that the three remaining arches are all that was left of ‘a bridge series of thirteen arches in all’. Where he got the figure of 13 is unclear, as all of the sources seem to point to twenty, but he hit on a point that appears to have been missed by later writers – that the twenty arches did not refer to a sum of all the arches crossed in a progression of island-hopping.

From no place could all four of the present bridges be seen at a time, and from most places the most would be two, so this scenario stretches credulity. Clonmel Old Bridge has three arches, Suir Island has two; Green Lane Bridge and Dry Bridge had three and eight respectively – totalling sixteen.

There were four millrace arches in the wall alongside the road on Suir Island, making the twenty, though another millrace arch on the northern bank was blocked up some years ago, making 21, so the sums do not add up.

The solution is suggested by the various maps of the town, particularly the first-edition OS six-inch map of 1841. This shows the bridge and the road leading southward from it as continuing in a straight line for 160 metres and then stopping dead at the water’s edge.

On the southern bank a road runs up to the river margin and also stops dead. There is a clear suggestion that the bridge originally ran in a straight line and it seems probable that it was as late as the latter part of the 18th century, or even into the opening years of the 19th, before the southern section of the bridge was demolished and the road diverted over three shorter, island-hopping bridges.

This option is supported by the description given by Smith in his history of Waterford, dated 1745, wherein he recorded that the bridge at Clonmel ‘is divided into two, by a small island in the river, on which houses are built’. Note that this says two, and not four.

References to the Suir islands


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Fig 2: Detailed architectural surveys and assessments of Old Bridge were required as part of the Clonmel Flood Relief Works (courtesy of Irish Archaeological Consultancy Ltd)

Mentions of the islands are sparse to non-existent in history. In the forty-year period from 1609 to 1648 there is not one reference to any island in the minutes of Clonmel Corporation. Early mention of mills refer to two mills ‘on the bridge’; one of these was at the northern end, the other at the southern side of the northern channel. There is no mention of any mill on an island until a rape mill is mentioned in a deed of 1711.

It seems likely that towards the end of the 18th century when water power for industrial purposes became a major element of the town’s economy that low banks in the river were raised artificially to create the islands.

Archaeological excavations carried out on the islands have found that the natural surface level is deep beneath the surface and covered with fill.

There is a map dating from about 1690 that shows the bridge in a straight line. This is one of a series of surveys carried out of the fortifications of towns around Ireland by J. Goubet. Only 15 arches are shown before the bridge reaches the edge of the page, while no islands are depicted. Lyons came to an interesting conclusion:

This is the only ancient portion of a bridge series of 13 arches in all. This ancient portion – of three arches – was widened by a third of the present width about the middle of the 18th century. From the fact that the bridge-piers (which are in their ancient state on the west side) are higher than the present roadway by about 18 inches, the writer infers that the original structure was a flat-beam bridge, and that the present semi-circular arches are comparatively modern. The roadway of the presumed wooden bridge was higher than the present one; and the old piers seem to have been lowered in the centre to accommodate the roadway to the arches.

The logic of this argument is difficult to follow and there would seem to be no reason for having a hump-backed bridge consisting of masonry piers with timber spans.

He also made a case for the presence of a barbican on the bridge at the entrance to the town in the Norman period and if that was the case it is likely that one of the spans was of timber, as a drawbridge. It seems far more likely that the bridge had masonry arches with pointed segmental intrados.

Clonmel Flood Relief Scheme


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Fig 3: Clonmel Bridge’s surviving pointed segmental arch

The work carried out on the Clonmel Flood Relief Scheme in 2010-12 presented the opportunity for the close examination of the bridges and other features in the vicinity. Of the four millrace arches to the south of the bridge, one retained its pointed segmental arch and this is seen in Figure 3 (right).

This span was plank-centred and the impression of the boards is visible on the barrel of the arch. The spans and piers on the upstream side, from north, and 4.13/3.73/5.62/3.78/5.51 metres. The downstream section of the bridge, which is the later addition, differs slightly, having spans and piers of 5.40/3.25/6.07/3.29/5.88 metres.

The arch rings on the outer two arches are almost semi-circular, while the central arch is three-centred. The outer two arches have irregularly shaped ring stones and hence this cannot be used as an indicator of the period of construction.

The 3.75-metre thick piers (see main featured image) and the span to pier ratio of 1.5 to 1 are compatible with an early date and strong indicators that they are originals apart from the top courses immediately below the springings.

The most remarkable feature of the bridge is the cutwaters. The downriver cutwaters on the extension are trapezoidal in plan, 3.25 metres long and 2.8 and 3.0 metres thick at the pier face, respectively. The upriver cutwaters are only 2.2 metres long and are triangular, but are almost as thick as the pier faces.

The angle of the upriver cutwaters is about 75 degrees – quite sharp, and are built of rubble masonry with small stones. The downriver cutwaters are even sharper, at 40 degrees. The significantly larger cutwaters on the downstream side suggests that they may have been built as buttresses to protect the bridge during the floods and strong currents for which the Suir at Clonmel is known. Similar downstream cutwaters, though not as long, may be seen at Carragh Bridge.

The undersides of the three arches have been coated with shotcrete, concealing the joint between the original bridge and the extension, though the joint is visible in the piers and abutments. The millrace arch next to the bridge on the southern side was concealed behind a timber sluice gate until it was removed during the flood relief scheme in 2011 and the arch was closed up.

Preserved shotcreted arch


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Fig 4: Clonmel Bridge – downriver cutwaters and rebuilt arches

Examination of the interior prior to its closure revealed an arch that had not been shotcreted and was so well preserved that the mortar in the crown of the arch retained marks of the straw or reeds used on the centring. This arch is segmental and almost semicircular, though smaller than those adjacent, with a span of 4.3 metres.

The junction with the extension is very plain to see, as the arch of the extension is wider, at 4.9 metres, and segmental; this new arch retains the impressions of plank centring. The old and new sections are 5.8 metres and 2.6 metres wide respectively.

Further evidence of the later date of the downriver extension was provided by the parapet wall copings which were larger and better hewn on the downriver side, though these were replaced when the parapets were rebuilt as part of the flood relief project in 2011.

Lyons states that about 1830 a Mr Hughes, miller, obtained a reduction in rent from Clonmel Corporation on condition that he remove portion of a building projecting on to the roadway on the downriver side at the south end of the bridge.13 This provides further evidence of the downriver widening.

He was also of the opinion that the south abutment of the bridge was the base of a former barbican tower. He mentions a culvert on the north end, which carried the flow from the former Manor Mill. The Civil Survey states that there were two grist mills ‘on the bridge’, which Lynch doubts because he interpreted the phrase literally.

It is quite likely that, as at Athlone in 1570, the mill frontage projected on to the roadway. The 1830 date sounds plausible for the widening of the bridge; this would have been a time when the milling industry on the islands was intensely busy and the narrow bridge would have impeded traffic.

Date of initial construction


But what of the date for the initial construction of the bridge and the replacement of the arches? The original width of the Clonmel Bridge was 5.8 metres, not unusual for a 14th-century bridge and it would appear that this is when the bridge was built. There are two possible reasons for the reconstruction of the arches.

The first could be due to the need for greater flow through the bridge, given that the development of the islands restricted the flow of the river into two channels rather than being able to flow over the gravel banks, as previously. The second would be reconstruction following collapse, due to floods or neglect.

In January 1638, the Corporation of Clonmel appointed three men to examine the ruins of the great bridge with the masons and carpenters of the town and to ascertain who would repair the ruins.14 The nature or extent of the damage is not specified. It is not out of the question that this is when the arches were rebuilt.

The arch rings of the two surviving arches, being the outer two, are in unshaped stone, with triangular keystones and with the lower stones in the arch ring not being radial, but at a steeper angle.

The arch ring in the millrace arch is similar and the presence of straw or reeds in the centring may also point to an earlier date than the 18th century. The centre arch was rebuilt in the 1920s after it was blown up during the Civil War.

 

This article is an excerpt from a new revised edition of Irish Stone Bridges – History and Heritage, published by Irish Academic Press, 438pp; ISBN: 978-1-911024-14-9 (written by Peter O’Keeffe and Tom Simington; revised by Rob Goodbody). Click here for more details and for your chance to win a copy of the book.

http://www.engineersjournal.ie/wp-content/uploads/2016/11/Old-Bridge-Clonmel-1024x580.jpghttp://www.engineersjournal.ie/wp-content/uploads/2016/11/Old-Bridge-Clonmel-300x300.jpgMary Anne CarriganCivilbridges,masonry,structures and construction,Tipperary
The town of Clonmel in Co Tipperary is believed to have been founded by the de Burgos in the 13th century. From 1338 to 1583, the lands were owned by the earls of Desmond. In Tipperary: History and Society (1985), Bradley states that Bridge Street is mentioned as early...