N2 Carrickmacross Bypass

Earthworks

Location: Carrickmacross, Co. Monaghan
Client: Jons Moneley JV
Project Value: €25 million
Completed: 2005
Country: Ireland

AGL Consulting were geotechnical designers to the Jons/Moneley JV on the Design-Build contract for the N2 Carrickmacross Bypass which involved the design and construction of 9.8 km of wide single carriageway national primary road with embankments up to 8-10 m high over soft ground, cut sections up to 20 m deep through drumlins, and 10 structures including bridges and reinforced concrete box culverts. Our scope of work included the following:

• Earthworks design, drawings and contract specifications.
• Preparation of the geotechnical interpretive report.
• Geotechnical design of structure foundations.
• Supplemental ground investigations with cone penetration testing in soft ground areas.
• Assessment of karst risk at the northern end of the scheme with additional geophysical investigations, trial pits and embankment formation inspections.
• Design for staged construction of embankments over soft ground with surcharging and monitoring of settlement and pore water pressures.
• Design of geogrid reinforcement for steepened embankements
• Finite element analysis of composite abutment structure for an existing historic masonry arch bridge that was incorporated into the permanent works under a new embankment.