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

The challenge lay in designing a high quality structure that could be constructed economically in complex soft ground conditions; settle well within a rural environment; and service a very busy traffic flow.

Highlight

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