N7 Naas Road, Co. Kildare, Ireland.
Summary
Roughan & O’Donovan, in alliance with AECOM, provided full engineering design services for the extension, from four to six lanes, of this major dual carriageway.
The road is a major link in the chain of the national road network connecting Cork, Waterford and Limerick to Dublin and carries on average 62,000 vehicles a day.
Awards
The scheme gained the first CEEQUAL award in Ireland, demonstrating ‘very good’ environmental performance during its planning, design and construction phases.
Solution
We were responsible for the design of the full scheme, including:
- online widening of 14km of dual carriageway from 2 to 3 lanes
- four new grade separated junctions
- 14km of new local roads
- four new interchange bridges
- two footbridges
- 17 sign gantries
- 12 culverts
- new streetscapes and traffic calming in Kill and Johnstown
We also undertook:
- integrating the traffic management phasing for carrying out the works into the alignment design
- integrating the design and construction programmes
- supervising execution of the works
- design check
- role of health and safety co-ordinator on behalf of the PSDP
We kept two lanes of traffic open at all times, minimising disruption to the local community.
Challenge
Ecology
We used a wide range of environmental mitigation measures to minimise impacts from the project, including:
- badger fencing
- bat boxes
- relocation of 350 brown trout
Archaeology
Nine archaeological sites were revealed during the archaeological investigation and prior to works taking place. We employed archaeological consultants to excavate and report on these finds.
Sustainable Resource Management
We reduced the amount of virgin aggregate and re-used existing materials on site, wherever practical. Where virgin materials were used, they were procured from a quarry located adjacent to the site, thus reducing transportation requirements and the associated impacts of vehicle movements.
We also developed a design to reduce the existing concrete pavement to rubble with a controlled breaker. This allowed plate load tests to prove the foundations, thus eliminating the need to remove the concrete and capping.
Services provided:
- Civil engineering design
- Environmental engineering consultancy
- Health and safety co-ordinator/PSDP
- Site supervision
- Traffic engineering
