2010:160 - The Peace Bridge, Clooney, Derry, Derry

Monitoring of topsoil-stripping works associated with the construction of the compound for a proposed development site across Foyle River (The Peace Bridge), Derry, was undertaken during 17–25 November 2009 by FarrimondMacManus Ltd (Excavations 2009, No. 182, AE/09/194), in relation to a proposed development site located across Foyle River, from the quay wall adjacent to the junction of Foyle embankment and Whittaker Street to Ebrington embankment, comprising the construction of a self-anchored suspension bridge.
The proposed development site lies within an archaeologically sensitive landscape, being located adjacent to the earthworks terracing outside the Star Fort walls which are associated with the scheduled monument of Ebbrington Barracks itself (LDY014–072), and within the general vicinity of numerous other archaeological and heritage sites. In addition, an historic landscape feature in the form of a raised ridge which appears to represent the remains of an access laneway marked as leading to a landing stage on the OS map of 1904–5 extends roughly east–west within the southern portion of the proposed compound area. Monitoring within the area of the proposed compound (Phase 1) revealed mixed brown/grey loamy clays, presumably associated with the land-reclamation works previously undertaken within this area in the late 19th century. Construction level was achieved within these reclamation deposits. Moreover, due to the nature of the underlying soils, the central portion of the compound area was not stripped of topsoil. Within this area of the site, the grassed area was covered with overlapping layers of geotextile (Terram) which was in turn covered with imported permeable compacted stone, which will be removed and the area reinstated to its previous condition upon completion of the proposed construction works. Such works will ensure the preservation in situ of the historic laneway mentioned above.
No previously unidentified archaeological features were identified during this phase of monitoring works at the site.
A further phase of monitoring works was undertaken during 8 March–1 July 2010, under an extension to the existing licence, in relation to the excavation of the east and west bridge abutments and the terrestrial bridge support located within the compound area.
The proposal at the west abutment is to provide a concrete spread footing support. This will be constructed by excavating behind the existing sheet pile quay wall to create a working platform. From this platform eight mini-piles will be placed to provide a suitable foundation and the reinforced concrete abutment constructed. A section of the modern concrete quay wall will be removed to enable the bridge deck to land on the abutment and a suitable reinforced concrete cap constructed on the modified quay wall.
On the maps dating to the mid-19th century, the area of the west abutment is shown as a being located near the end of a wooden wharf projecting out into Foyle River. However, the area had undergone considerable development by 1904, with the reclamation of the area and construction of a railway to the immediate west of the area of invasive groundworks. Monitoring within the area of the west abutment revealed that further works had subsequently been undertaken with removal of the Bitmac surface and underlying sub-base material revealing a large concrete inspection chamber which measured approximately 3m3 internally. Access to the chamber was originally provided through a manhole cover, though this had subsequently been sealed by the pavement surface and its associated sub-base layer.
As the proposed invasive groundworks associated with the construction of the west abutment are limited to a smaller footprint and considerably less depth than the existing inspection chamber and associated modern disturbance, no further archaeological works were undertaken within this area of the site.
The design proposal for the east abutment is a concrete abutment on spread footing constructed on a reinforced earth wall. This reinforced earth structure will be benched/keyed into the existing earth embankment and constructed in lifts/layers. Following placement of the reinforced earth wall, a reinforced concrete abutment will then be constructed to enable the bridge to be landed. Ground works associated with the current development proposal consisted of the removal of grass and topsoil from the upper and lower portions of the terraced earthwork to a depth of c. 0.2m, within an area extending c. 35m along the embankment and c. 20m wide, and the subsequent excavation of a portion of the lower terrace within this footprint to a depth of c. 3m below the top of the terrace, level with the existing compound area and within the layers associated with the 19th-century reclamation of the area associated with the construction of the railway along the eastern bank of the Foyle River. Works associated with the terrestrial bridge support were also undertaken within the deposits associated with the reclamation of the area.
No previously unidentified archaeological features were identified during monitoring works at the site.