North Wall Avenue, a new street in the Dublin Docklands with innovative tree-root soak-pits for sustainable drainage
A new 330m urban street connecting North Wall Quay and Sheriff Street Upper in Dublin's docklands is expected to open to traffic in January.
New Street, North Lotts will open up several significant development sites adjacent to Dublin Point Village.
PWC, acting as receivers for Wintertide Ltd., appointed Roughan & O'Donovan to provide all engineering services for the project from concept, through planning and detailed design, and including contract administration and construction supervision.
Solution
The solution comprises:
- 330m and 6.5m wide road carriageway, designed to accommodate all vehicles, including HGV
- footpaths in high quality paving materials, with complementary trees and street furniture
- three new signalised junctions incorporating high quality facilities for pedestrians and cyclists
- installation of new services, including foul and service water sewers, ESB, traffic and communications ducts, district heating pipes and corrosion resistant watermains
Challenges
Ground conditions
Roughan & O'Donovan identified an area of contaminated land within the footprint of the proposed new street, which had the potential to add significantly to the street’s construction cost.
Dublin City Council agreed, however, that the material was doing no great harm where it was, and digging deeper than was required for the road could cause changes to the local hydrology.
The excavation was then limited to that needed for the road construction, and contaminated material below that level was left in situ.
Services
The scheme required the installation of new services beneath a live Luas (Light Rail) line, the most difficult of which to accommodate was pipework for a future district heating system.
The connection across the Luas line was achieved by pipe-jacking 5 large steel ducts across and routing the services through these. The tolerances on movement of the Luas line were extremely onerous, with anything over 4mm requiring an inspection and 6mm requiring a cessation of services and a six digit fine.
Roughan & O'Donovan devised, in consultation with Transport Infrastructure Ireland and Transdev, a monitoring regime to actively monitor track movements in real time. This was the first time such a monitoring regime was used in Ireland, and the template has since been copied for other works around the Luas light rail system.
Success
In commenting on the project, Roughan & O'Donovan's Eoin Ó'Catháin said:
Overseeing the installation of new services beneath a live Luas line, without any disruption to operations, represented a significant achievement for the team.
