2002:1026 - KILKENNY: John’s Bridge, Rose Inn Street/John’s Street (Site Nor 11), Kilkenny

As part of the River Nore (Kilkenny City) Drainage Scheme, excavations resumed in 2002 in the area underneath and adjacent to the existing John’s Bridge. Previous work at this location consisted of underwater exploration and excavation by the Archaeological Diving Company (ADCo) and test-trenching carried out by the writer in autumn 2001 (Excavations 2001, Nos 704 and 705).

Preparatory work in spring 2002 at John’s Bridge consisted of the underwater excavation of a deep ‘central channel’ by David A. McCullough of ADCo (see No. 1017, Excavations 2002). The excavation of this central channel allowed for the lowering of the water level during the summer months. This reduction in the water level facilitated the creation of two banks or bunds of river gravels on either side of the river channel. The use of pumps within these embanked areas ensured a dry area, which allowed a team of archaeologists to excavate and record the earlier bridge structures. As a result of this strategy, the remains of a late medieval bridge, which was swept away by a massive flood in 1763, were revealed directly underneath the existing bridge.

The remains of an 18th-century masonry bridge were also found, immediately upstream of the existing bridge. This 18th-century bridge was constructed after the flood of 1763 and consisted of a three-arch masonry structure. This bridge was removed in c. 1910 and replaced with the concrete structure surviving today. Part of the abutment from the 18th-century bridge survives in a visible position on the eastern bank of the Nore. The 2002 excavations succeeded in recording the foundations of two massive piers from this bridge.

The two 18th-century masonry piers, which were spaced c. 14m apart, had upstream and downstream points or cutwaters. The masonry element of both piers survived to a height of 1m and was 13m long and c. 3.5m wide. The piers were composed of a stepped ashlar or dressed limestone face with a rubble core, bonded by a very compact mortar. For extra strength the ashlar blocks, some of which were over 1m square, were strapped together with iron bars running along the perimeter of the pier. The iron bars were set into grooves in the upper faces of the ashlar blocks, with any remaining space in the grooves filled with lead.

The masonry piers sat on what can be best described as a raft foundation. This was a composite structure of substantial timber beams, ashlar and mortared rubble stone and can be divided into the upper and lower rafts. The upper raft was a series of timber beams running the entire length of the pier; these protruded beyond the upstream and downstream cutwaters. The beams were of pine and spruce and measured 350–400mm square. Gaps between the beams were filled with limestone ashlar blocks, some of which were also strapped together by iron ties. The lower raft was constructed in a similar fashion; however, the timbers were perpendicular to those of the upper raft, i.e. running across the width of the pier. An interesting feature was that the timbers of the upper and lower layers of the raft foundation were pegged into each other with numerous timber dowels.

The timberwork surrounding the raft foundation for the piers was equally impressive. The sides of the raft were shielded by timber shuttering. This shuttering comprised numerous timber planks set into the gravels on their long axes and fitted into each other by tongue-and-groove joining. At the upstream part of the eastern pier a heavier form of shuttering was used. Pointed timber posts were driven into the gravels, and a plank was neatly fitted into the space between each post. A groove in the side of each post accommodated the planks. This shuttering was held in place by a number of horizontal beams, to which it was nailed. The purpose of the shuttering may have been to prevent scouring of the raft foundation, or, alternatively, it may have acted as a form of shoring to enable excavation to sufficient depth for the raft foundation.

Additional protection against scouring was provided by the construction of a timber frame c. 1.5m from the pier foundation. Within this timber frame, a thick apron of large stones was tightly fitted. The stones were placed on edge with their long axes pointing downward into the river gravels. Additional timber shuttering was placed at the upstream and downstream ends of the stone apron, presumably to prevent scouring.

Excavations directly underneath the existing concrete bridge exposed the remains of the bridge that was swept away in the flood of 1763. Contemporaneous illustrations of this bridge indicate that it was a multi-arched structure composed of five to seven arches. The collapsed remains of three masonry piers were revealed, as well as the debris from the collapsed superstructure of the bridge and the arched vaults. Wickerwork impressions from the matting used to construct and centre the vaults were evident in the mortar render of some of the masonry fragments. Documentary research on these bridge remains is continuing.

A number of substantial oak timbers from the pre-1763 bridge were also recovered in the area around the masonry piers. These were large oak verticals, 1–2m long and 0.3–0.45m thick, but tapering to a point at the bottom. Iron points or shoes were present on most of these timbers and were clearly intended to facilitate the driving of the piles into the river gravels. Although dendrochronological dates are awaited for many of these oak piles, it is clear that a small group of them can be dated generally to the late 16th–early 17th century. This group of timbers is likely to be associated with recorded maintenance and rebuilding at John’s Bridge in 1618. The purpose of some of the timbers is likely to have been to protect the foundations of the masonry piers from the scouring action of the river and to aid in the construction of piers. Two oak horizontal timbers have been recovered from John’s Bridge, which slotted into vertical grooves in the oak piles.

An interesting feature of the John’s Bridge excavations has been the recovery of fragments of medieval grave-slabs from the bed of the river. These slabs were all found around the piers of the pre-1763 bridge and include two with Norman French inscriptions and one with a Latin inscription. Historical references indicate that the slabs were known to be in the river by 1618. Two collapsed post-and-wattle panels and stake alignments were also exposed on the west bank of the river. These have been provisionally interpreted as the remains of a fish-trap.

A large collection of small finds was recovered from the excavations. These included medieval and post-medieval coins, post-medieval weaponry and domestic objects, a large assemblage of clay pipes, and medieval and post-medieval pottery. Documentary research and post-excavation analysis of the excavated remains are continuing.

2 Killiney View, Albert Road Lower, Glenageary, Co. Dublin