CONSTRUCTION MAGAZINE GOES BEHIND THE SCENES OF A MAJOR INFRASTRUCTURE PROJECT
Project Name: Dunkettle Interchange
Location: Co. Cork
Sector: Civil Engineering
Main Contractor: Sisk
Sub-Contractors: Murphy International, Banagher Concrete, Fibro Menard, Shay Murtagh Precast, Motorway Care, Breedon, SSE
Project Manager: Jacobs
Developer: Transport Infrastructure Ireland (TII)
Engineer: Jacobs
Consultancy: Fehily Timoney & Co, Ramboll, Clandillon Civil Consulting (CCC)
Cost: €215million
Start Date: 2018
Completion Date: February 2024
Health & Safety: Health & Safety was a top priority to safeguard the workforce, the public and everyone involved in the project. At the time of substantial completion, the project team had inducted 2,547 people involved in the delivery of the project and over one million person-hours were worked to deliver the project.
Sustainability: Sisk disposed of as much material on site as possible. One of the other sustainability benefits we got was that we used The Office of Public Works (OPW) Management of Soil and Stone By-Products on Flood Relief Schemes Article 27 to its highest level. We imported material through Article 27. Cork Airport was resurfacing the runway at one point and we ended up importing materials from the runway on the embankment at Dunkettle. Sisk had to plan around the local ecology. There were lots of locations where we had to work around the ecology and we also had rare species that needed to be translocated to a pond north of the N25. It was an Environmental Impact Statement (EIS) commitment and there was a number of invasive species we had to identify, manage and treat. During the early stage of the project the Sisk onsite team developed a book of invasive species which the team could use as a reference point to identify invasive species at later stages.
BIM: Sisk developed a BIM model of the project. This model was then used to identify clashes in the design before being issued to the project team for construction. Over 150 clash items were mitigated in advance. This is a ‘hidden benefit of this kind of modelling that prevents issues from occurring.
And aeriel shot of the Dunkettle Interchange. Picture: Fennell Photography
Accelerating connectivity
The Dunkettle Interchange Project, situated approximately five kilometres east of Cork City centre, addressed critical infrastructure needs by upgrading the junction of four national roads: the M8 Cork – Dublin Motorway, the N25 Cork – Waterford / Rosslare route, the N40 Cork South Ring Road, and the N8 Dunkettle – Cork city National Route.
Led by Sisk, the project prioritised health and safety, with over 2,500 individuals inducted into the workforce and over one
million person hours worked. A testament to the immense scale of the project.
Sustainability efforts included maximising on-site material usage and leveraging the Office of Public Works (OPW) Management of Soil and Stone By-Products on Flood Relief Schemes Article 27 to its highest level.
One such example includes when Cork Airport was resurfacing the runway at a point during construction of the project and Sisk were able to import materials from the runway on the embankment at Dunkettle, helping reduce needless waste across both projects.
Sisk were careful to plan around the local ecology with Environmental Impact Statements guiding the protection of local wildlife.
The team identified multiple locations that required careful consideration of local ecology, including the discovery of rare species that needed to be translocated to another location for safety.
Moreover, they also worked to identify, manage and treat the risk of invasive species. During the early stage of the project the Sisk on-site team developed a book of invasive species which the team could use as a reference point to identify invasive species at later stages.
The project delivered 18 new road links and seven bridge structures among other upgrades. Picture: Fennell Photography
Additionally, Sisk implemented Building Information Modelling (BIM) to identify and mitigate design clashes, with over 150 issues resolved in advance.
Highlighting how the technology and modern advances in construction more generally are proving to be an invaluable tool in delivering projects from the minor to the mighty.
The project delivered 18 new road links, seven bridge structures, and upgrades to existing structures and roadways, including new walkways, cycleways and intelligent transport systems.
The Dunkettle Interchange Project represented a series of specific challenges, not least the quality of the ground itself.
Geotechnical challenges were addressed through innovative solutions such as Control Modulus Columns, surcharge, and band drains, with specialist subcontractors like Vibro Menard contributing expertise.
It’s a novel approach to the challenge faced in building the project, but it’s proving an effective method to strengthen the ground enabling the team to build the embankments.
They steepened the slopes of the embankments to a 70-degree slope by using a reinforced earth solution. So impressed by the results, it’s now been used widely across projects on different Sisk jobs.
The results are plain to see, despite traffic volumes reaching record highs, approaching 120,000 vehicles on busier days, the Dunkettle Interchange Project significantly reduced journey times during peak hours, with TII reporting nearly a 50 percent reduction on average.
This transformative upgrade not only enhances regional connectivity but also underscores Sisk’s commitment to innovation and sustainable infrastructure development.
