2013:509 - Bray Little, Bray, Wicklow

A flood defence scheme is being undertaken along 4km of the River Dargle. This work includes widening and deepening the river and including a new culvert at Bray Bridge. As part of the E.I.S. for the works two arches of an earlier bridge were recorded within the arches of the existing bridge over the Dargle in the centre of the town. It was recommended that these be excavated.

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 bridge a third arch was uncovered as a result of excavation under the northern arch. All these features and associated works were fully excavated.

Under the arch of the bridge at the northern bank of the river a buttress of a bridge was uncovered (Area A). This was surrounded by a thick layer of concrete up to 1.2m in depth which had been poured into the area after Hurricane Charlie (1986), to secure the existing bridge. This layer was removed by a rock breaker. The main section of the feature was random rubble walling with a lime mortar. Ashler walling was visible at the south and east. This consisted of large limestone blocks held together with a lime mortar. At the north this had been removed during the construction of the existing bridge. When the stone was removed a wooden raft foundation was uncovered. This consisted of seven interlocking timbers. Only two wooden dowels were recorded, the timbers were laid into notches in the base timbers. This would have formed a stable layer in clay base of the bridge and avoided subsidence.

The buttress under the central northern arch of the bridge was also surrounded by a thick layer of concrete (Area B). This buttress was visible at low tide. The main section of the feature was random rubble walling with a lime mortar. Ashler walling surrounded the feature on all sides. This consisted of limestone blocks held together with a lime mortar; the blocks were narrow and may have been added to finish the bridge as a cladding rather than for strength as in the previous buttress. When the stone was removed a wooden raft foundation was uncovered. This consisted of one timber at the centre and a large number of wooden stakes. These were concentrated at the west and north with some also visible at the east. The highest concentration of the stakes was at the apex of the buttress, this is the area with the fastest flow of water and the greatest possibility of erosion of the bridge. This timber frame is quite different from the foundation layer in Area A.

The southern arch of the bridge contained a buttress also visible at low tide. This was surrounded by sand and silt from the river. The main section of the feature was random rubble walling with a lime mortar. Ashler walling was visible at the south, east and north. This consisted of large limestone blocks held together with a lime mortar. The buttress was on a foundation layer of stone. This feature was truncated at the west by earlier works in the river. Unlike the other two buttresses there was no timber foundation in this area. This arch is out of the main flow of the river and is only used during high tides or periods of flooding.

The stone bridge exposed as part of the works appears to be an amalgam of two earlier bridges on the site, the 1736 bridge and the 1741 bridge. The buttress in the northern arch (Area A) is of a different construction than the two others that were recorded. It has larger dimensions, the limestone blocks are larger and the foundation layer is of a different construction. This feature was reused as part of the 1741 bridge. The buttresses in the remaining areas are of a similar size and the materials used are of similar dimensions. The buttress in Area B was laid on a foundation of wooden piles. This was concentrated at the west of the pier. There was no wooden foundation of the buttress in Area C, at the southern extent of the bridge, and this arch is drier.

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