civil engineering - bridges
N3 Navan Road Interchange
The bridge provides access over the N3 between the Phoenix Park racecourse development and the new Phoenix Park railway station. The bridge is a 2 span 60m long integral prestressed concrete bridge. The bridge has no bearings or joints. The use of pre-cast prestressed u-beams was necessary in order to minimise the road closures on this important commuter route into Dublin city. The design team were instructed by the client to achieve a structure that enhanced the adjacent development and acted as a signpost for it. For this reason the design team chose to use sculpted in-situ concrete piers in the median and pre-cast facia panels were arranged in a sloping fashion to prodive a focus to these piers. In addition the panels hid the low-energy LED lighting srips which were used to highlight the pre-stressed beams in the evening with a blue diffused light.
The project incorporated large approach walls due to the requirement to protect an underground service. An attractive step was designed into the precast reinforced earth wall and capping panels were cast on site to enhance the landscaping of this wall.
A requirement of the client was to reduce the carbon footprint of the development and associated infrastructure. The design team used a GGBS / OPC blended concrete in the mix design.
The bridge contains 18 pre-stressed U10 beams which were erected at night in a co-ordinated fashion between the Contractor, Gardai and Fingal County Council.
The bridge was designed to full NRA motorway standards and recently opened to all traffic.
The bridge has been accepted for the 2008 Irish Concrete Society Competition.
Value: |
€8m |
Start date: |
March 2007 |
Completion date: |
September 2008 |
Client: |
Flynn O’Flaherty |
