Atkins is an award winning designer of roads and bridges
Project: N25 Mahon Interchange
Client: O’Callaghan Properties
Atkins Role:
Atkins was commissioned to carry out the detailed design of external infrastructure for the Mahon Point Development in Cork. This included major improvements to the N25 South Ring Road to accommodate additional traffic generated by the Mahon Point development. This involved the design and construction of works in an urban environment with complex traffic management requirements.
The scheme involved major improvements to Mahon Interchange, including two signalised junctions, a new over-bridge and the widening of the N25 South Ring Road, to dual three lanes, between Mahon Interchange and Bloomfield Interchange. It also included the installation of gantry and cantilever signage. The Mahon Link Road was dualled and a further signalised junction provided at the entrance to the Mahon Point development.
MOVA technology was employed for traffic signal junctions at Mahon Link Road and Interchange to cater for variable traffic flow patterns throughout the day generated by the Mahon Point development. The signal junctions are remotely monitored from the Cork City UTC SCOOT system.
The project involved the design of a 36m clear span portal sign gantry using steel rectangular hollow sections. The gantry spans the N25 South Ring Road and a central support was not permitted due to the narrow median with concrete safety barrier. A bespoke design was required, as the height of signage required on the approach to the Jack Lynch Tunnel did not permit the use of generic NRA sign gantry details.
The gantry design also included the longest cantilever sign in Ireland (10.5m overhang) in order to suit site constraints at the Mahon Interchange westbound exit
The new over-bridge at Mahon interchange was an extension of the existing interchange bridge. The bridge deck consisted of precast concrete beams in order to minimise disruption to traffic on the South Ring during construction.
