N25 Waterford Bypass

Ireland

N25 is a major PPP scheme for the NRA and involved the design, build, financing, operating and maintenance of a new 23-kilometre motorway by Celtic Roads Group (CRG) which is managing the N25 throughout the concession which runs until 2039. It is one of three major PPP road schemes successfully delivered by the CRG in Ireland. A major feature of the N25 Waterford Bypass is the 465m long cable stay bridge over the River Suir. This new crossing of the River Suir is to the west of Waterford City, and has a single pylon 112m high on the south side with a main span of 230m over the river.

River Suir Bridge Statistics:

  • Overall width: 32.60m
  • Overall length: 465m
  • Main span of 230m
  • Overall Tower height: 112m (above foundation) 
  • Tower width at base: 53m
  • Total length of cable: 11900m
  • Deck Steel: 2,829t

Pylon foundation design: The combination of difficult ground conditions and use of a single pylon challenged BAM-Dragados JV to develop a radical solution for the design of the pylon foundations. BAM Dragados and Geocisa, the geotechnical division of Dragados, designed a rotary-bored micro piling system to penetrate the fragmented sandstone strata and weathered mudstone.