2012:641 - Bray Little/Ravenswell/Bray Commons/Killarney, Bray, Wicklow

Monitoring is being undertaken for a flood defence scheme on 4km of the Dargle River. This works include widening and deepening the river and including a new culvert at Bray Bridge. Works uncovered a number of features at Bray Bridge.

The earliest bridge recorded in Bray in 1666 crossing the River Dargle was replaced by a four-arch bridge in 1736. This bridge collapsed in a storm and was replaced by another four-arch bridge in 1741. The current bridge was constructed in the middle of the 19^th century. Two buttresses of the earlier bridge are visible at low tide under the southern arches of the existing bridges; these will be excavated in the summer of 2013.

Underneath the existing bridge an earlier stone structure was uncovered; this was an amalgam of the 1736 and the 1741 bridges. The eastern section of the bridge consisted of two parallel walls in-filled with sand and gravel. This was part of the 1736 bridge. The second wall at the west was constructed in 1741; it was a large wall with a culvert. A cobblestone surface was also uncovered in places.

To the west of the stone bridge on the Lower Dargle Road, a section of an earlier wooden bridge was uncovered. This was uncovered within what was the river bed. The bridge consisted of a large base plate (T101) with three upright timbers inserted into it (T102, T103 and T104). Two timbers were initially visible crossing horizontally but these collapsed upon exposure. The timbers appear to have been laid directly onto the river bed. There was no evidence of an excavated trench. The base plate was orientated south-west to north-east. The base plate was 6.9m in length, 0.42m in width and was 0.25m thick. At the south-west it was partially damaged by the insertion of metal piles. Three sub-rectangular mortice joints and a cross-shaped double mortice were recorded in the timber. The rectangular mortises were cut through the timber to support the upright timbers. These measured 0.3m x 0.2m on average. The upright timbers or “tenons” were cut for insertion into the timber. This method of using mortise and tenon joints creates a very strong joint.

An interesting double cross-shaped mortise joint contained two through mortises, at the north. This would have held an upright timber and contained the remains of a wooden wedge. The second mortise may have been a splayed joint. These can often be held in place with a brace but this was not visible. A timber was recovered (not in context) which would have been placed in this joint and splayed towards the south. This would have given extra support to the upper level of the bridge. The tenon was held in place using a wooden wedge, the remains of which were removed.

Analysis of the timbers by Ellen O’Carroll has show that the larger timbers are oak and the timber wedges are alder and holly. Dendrochronology dates for T101 indicate a felling date range of AD1116 ± 9 years or later. The date for T102 is AD1100 ± 9 years or later, or after AD1100. This would indicate a late 12^th century or early 13^th-century date for the bridge.

Further works will be undertaken during 2013 within the river bed and further remains of this bridge may be uncovered.

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