2006:1986 - Gracedieu East, Waterford

Monitoring of the construction of a bridge crossing over the River Suir was carried out in Gracedieu East townland during construction of the N25 Waterford city bypass. The areas to be impacted on by the bridge foundations were not investigated during pre-construction test-trenching due to the unstable intertidal ground conditions. There are no recorded wrecks in this fast-flowing area of the river channel. The bridge area was also surveyed by side-sonar scan and caesium vapour magnetometer and nothing of archaeological significance was indicated in these surveys. The bridge pylon in Gracedieu East townland will be fixed on a pair of pile caps, each measuring 18.8m by 14m and up to 5m in depth, and these will be located at a distance of 29.6m apart. The construction methodology for the bridge pylon foundations involved reducing the entire pylon area to a depth of 5m below modern ground level over an area measuring c. 60m north-west/south-east and 20m wide. The stratigraphy consisted of alluvial estuarine muds, which contained moderate inclusions of reeds and occasional non-archaeological wood. The excavated soils were retained on site and were periodically inspected for archaeological finds. Following ground-reduction works the excavated area was infilled with a hardcore stone fill in order to create a stable working platform prior to commencement of piling. The pile caps, which will be excavated into the stone fill, will not extend below the base of this material and will each rest on 48 driven steel micro-piles. No archaeological features or artefacts have been uncovered to date and monitoring of the remaining bridge construction works will continue during 2007.