Winner of both the ACEI 'President’s Award for Design Innovation' and the ICS 'Infrastructural Category Award' in 2011.
Tony Dempsey

Tony Dempsey

Director
Client
Direct Route Construction Joint Venture
Location
Co. Clare
Market

Summary

Roughan & O'Donovan completed permanent and temporary works design of this major, multi-span viaduct at the N7/N18 interchange northwest of Limerick City.

Solution

Structure B11 on the Limerick Southern Ring Road Phase II (Limerick PPP Scheme) carries N7 mainline traffic over a slip road and tidal creek.

It comprises:

  • Fully integral, twin viaducts, 169.6m and 178.5m in length
  • 6 spans on the south structure and five spans on the north structure
  • In situ cast reinforced concrete boxes with a maximum span/depth ratio of 23
  • Inset, single leaf piers to minimise visual impact
  • Shallow deck cantilevers to enhance the bridge’s slender appearance

Challenge

Designing a high quality structure, which could be constructed economically in complex soft ground conditions and settle well within a rural environment servicing a very busy traffic flow, proved challenging.

Our innovative design provided substantial benefits, in terms of construction and whole life maintenance costs, to our client.

Services provided:

  • Bridge engineering design
  • Geotechnical design
  • Temporary works design
  • Alignment and road works engineering design