Luas Cross City
About This Project
Luas Cross City extension project is one of Ireland’s largest infrastructure projects to date and links the Green and Red Luas lines in Dublin city. The project comprised of 5.9km of track, adding 13 new stops, eight of which are in the city centre. Construction on the €368m line began in 2013 and was delivered on time and on budget in late 2017 and has recently won the accolade of Best Project in the Civil Engineering Category at the inaugural Irish Construction Excellence Awards.
Murphy Surveys played a critical role in the success of the project, delivering surveying and engineering services for the entire development. Our Head of Digital Construction, Michael Durnin, acted as Chief Surveyor with SS JV and oversaw all aspects of survey and geospatial data collection including establishing a control network, setting out, deformation monitoring and subsurface mapping.
Michael and the team engaged early with the client during the pre-construction stages. We have a strong professional relationship with Sisk Group and collaboratively, we have and continue to work on multiple construction and infrastructure projects.
Technical sensor driven solutions were offered on this project as an alternative to a typically manual monitoring process reducing cost and automating the data capture process. Data management workflows were also integrated into this project for all design data used by field surveyors, increasing on-site efficiencies, with site staff quoting up to two hours a day saved due to productivities gained. The teams provided the scale and technical expertise the client and project required whilst managing and taking ownership of all geospatial work.
Challenges during the project included TII’s construction specifications. 1mm relative change over 1m of track were extremely tight tolerances for rail construction. 1:60,000 linear accuracy and 5√k for control are both very difficult to achieve in a heavily urbanised environment and in phased construction works.
The specification also included localised variables for paving under tight constraints where real-time decisions against design needed to be made for surveyors setting out in the field. Deformation monitoring of national monuments and retaining walls in the urbanised environments and heavy work zones had trigger values of 2.5mm.
Despite facing tight constraints and the challenges of such a large and complex site, the survey works were completed to a high standard as per specification and to client’s expectations. Once the Luas Cross City line was opened, Michael and the team continued to work with our client to capture asset information and conduct topographic surveys.
Key Construction Statistics
- Total single line track: 13.4km
- Total weight of the tracks: 1,520 tonnes
- On street, concrete track bed and shoulders poured: 13,600m3
- Total ducting and pipes under the surface: 178,000m
- Daily average distance walked by a foreman: 12km
- Projected total man hours to complete SSJV works: 3.0 million hours
- Number of people who worked on the mains infrastructure project: 3,398 overall, 583 at peak (March 2017)
SS JV comprises of Dublin-based construction company, John Sisk & Son and Steconfer, a Portuguese construction company specialising in railway works.
TTI, Transport Infrastructure Ireland provides an integrated approach to the future development and operation of the national road network and light rail infrastructure throughout Ireland.
Infrastructure, Light Rail