R402 Enfield to Edenderry Road Improvement

Project Summary

The R402 Enfield to Edenderry Road Improvement Project involved the construction of 11 km of the realigned single carriageway of the R402 regional road between Enfield and Edenderry, County Kildare, Ireland.

Project Description

Coffey Construction was the main contractor for the project and undertook the majority of the works using our directly employed staff and labour and our own fleet of plant and equipment.  Sub-contracted works included macadam surfacing, white lining and connections for public lighting.

The majority of the new road had a cross-section consisting of the 7.3m carriageway, 2.5m hard shoulders and 3m verge.  The total road construction width was narrower for 2.1 km of the route as a result of physical restraints, such as within villages.  The works consisted of both online and off-line improvements of the existing alignment.  All side junctions affected by the realigned carriageway were also realigned and some were newly constructed.  A new roundabout junction was constructed where the new alignment crossed the existing R402 at Carberry Village.  The works were adjacent to the Carbury Bog Natural Heritage Area.

Project Delivery

10 new concrete culverts were constructed over local watercourses, and 2 of these replaced existing culverts within the online improvement sections of the works, and these carried significant streams. These streams discharged into the River Boyne and River Blackwater SPA and the River Boyne and River Blackwater SAC, and our methods statements for works around the water courses were reviewed and approved by Inland Fisheries Ireland.  The precast concrete box section units for these two culverts were designed and supplied by our precast concrete supplier.  Each culvert included guard rails, reinforced concrete headwalls and wing walls and gabion mattresses.  Several cattle underpasses were also constructed.

New road drainage was installed along the route, including gulleys, collector drains, filter drains, grassed channels, manhole chambers and stormwater attenuation ponds.  A total of 23 km of drainage pipes were installed which ranged from 225mm to 900mm in diameter.  There were 10 stormwater attenuation ponds along the route which had a combined storage capacity of 7,700m3.

As Main Contractor, Coffey Construction was responsible for liaising with all utility providers, landowners and fisheries bodies to enable construction of the works.  Over the length of the new road, numerous utility services had to be protected or diverted, particularly along the sections of on-line improvement.  We appointed an engineer to act as utility coordinator for the project who formed a focal point for agreeing with the utility companies how services conflicts would be resolved.

A significant number of new utility services were installed as part of our works.  These included 10 km of PE water mains, the majority of which were 315mm diameter, and 5 km of ductile iron water mains, the majority of which were 300mm diameter.   40km of ducts were installed, which were primarily for telecoms and data services.  Short lengths of new ducting were installed for the DNO which were primarily related to the diversion of HV and LV cables.

The project involved extensive traffic management on a busy regional road with a predicted 24 hour Annual Average Daily Traffic of 5,600 vehicles.  The temporary traffic management measures were carefully planned, designed and implemented by Coffey Construction personnel, and proposals were submitted to and discussed with Kildare County Council Highways Department, the local police and the Client’s team in advance of each phase of the works.  Traffic was controlled using a combination of methods to maintain traffic flows on the existing road, including road speed limit reductions, single lane shuttling, ‘all stop’, and convoy working.  These methods eliminated the need for road closures.  Competent personnel were appointed to carry out the TTM roles, and these positions included: Traffic Safety and Control Officer (TSCO), Deputy TSCO, TM Designer and Temporary Traffic Operation Supervisors (TTOS).  Roadworks speed limit orders were applied for and granted to reduce the speed limit of the roads in the vicinity of the works.  Road Safety Audits were carried out at the various stages of the project as required.

The project also included extensive fencing and boundary wall treatments, safety barrier systems, noise barriers, road signs, road markings, public lighting, various earthworks and various accommodation works, such as providing accesses to properties and lands.  Works also involved the demolition of some dwellings, outbuildings and other structures.

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