Wexford Bridges Rehabilitation Contract: Structural Investigation of O'Hanrahan Bridge, Island Bridge and Scarawalsh Bridge

Tender description

Structural investigations are required for three bridges in Co. Wexford: O'Hanrahan Bridge in New Ross (WX-N25-027.00), Scarawalsh bridge north of Enniscorthy (WX-N11-008.00) and Island bridge outide New Ross (WX-N30-010.00). O’Hanrahans bridge, constructed in 1967, is a 9-span structure with a simply supported post-tensioned beam and concrete slab deck. The structure carries the N25 single carriageway over the River Barrow in New Ross, Co Wexford. The structure has a maximum span length of 21.6m, minimum span length of 12.8m and an out to out width of 11.65m. The overall length of the structure is 175.4m. The structural investigation required for O'Hanrahan bridge is to allow a detailed post-tensioned special inspection (Phase 3) in accordance with AM-STR-06011 (NRA BA 50). The following as a minimum shall be investigated: - Concrete conditional surveys (half cell potential, resistivity testing, chloride content, cement content, cover meter surveys, carbonation). - Concrete stress determination - Tendon stress determination - Anchorage exposures and inspection - Tendon exposures and inspection (including grout sampling and testing). Scarawalsh bridge, constructed in the 1970s, is a single span, 39m long 14.7m wide post tensioned multi-cell box beam bridge. The structure carries the N11 over the river Slaney. The structural investigation of Scarawalsh bridge involves breaking out a section of concrete around the southern expansion joint to examine the condition of the run on slab and ballast wall. Island bridge, constructed in the 1980s, is a reinforced concrete box culvert carrying the N30 over a tributary of the river Barrow. The structural investigation of Island bridge involves breaking out a section of the existing parapet edge beam to confirm the R.C. details shown on record drawings.