Micro-trenching, Galway, Ireland
Enabling Fibre Optic Network.
The application Part 1.
Using Safetrack materials enabled the micro-trench which was required to run the cables between connecting junction boxes, placed at 1km intervals, to be cut at 20mm wide and 150mm deep as compared to the 200-300mm width and 600mm depth required with more traditional techniques, saving both time and money. A specialist machine was used for the excavation.
However the success of this new technique to cut the trench and lay the cables was reliant on the provision of an infilling technique that would successfully reinstate the road surface to a safe, serviceable state quickly and efficiently. This is what the HAPAS certified infilling materials are designed to do.
The material's cold application was also seen as a benefit by the client as failures had occurred on previous projects in Ireland were hot bitumen based products had damaged the fibre optic cables.
Galway City Council
- Micro-Trenching - Galway, Ireland
Application Part 2.
The Stirling Lloyd solution was then overlaid with Safetrack® Crack Infill, which is black in colour, to reinstate the surface. This material supports the trench on both sides and seals it from water ingress. Safetrack Crack Infill also helped the road retain its integrity by forming a strong bond between the cut faces of micro-trench. The material was finished flush to the road surface to ensure that no problems with standing water drainage or road ride quality would ensue, with aggregate being broadcast into the Crack Infill to provide the appropriate skid resistance.
The solution behaves like asphalt helping ensure a long and effective service life.
The speed and ease of application, using minimal equipment, together with their fast cure enabled the infill to be applied exceptionally quickly, converting what was perceived would be the slowest part of the trenching process (reinstatement) to the quickest. In fact the contractor was able to excavate, lay the fibre optic cable and reinstate up to 250 linear metres a day, compared to more traditional techniques which typically achieve less than 100 linear metres. In addition due to the small footprint of the installation, the works were carried out with minimal road closure time and disruption to the local community.
A spokesman for the contractor said “One of the key requirements for this project was a reinstatement process that would not compromise the road structure in anyway. Standard reinstatement products would not give us the strength and flexibility required, Stirling Lloyd’s solution however could.
After just one meeting with Stirling Lloyd we knew this was the solution we were looking for. They had a proven track record on the Shetland Island micro-trenching project and the HAPAS certification we required.”
The Stirling Lloyd solution met the strict installation, in-situ and post application performance criteria laid down by Galway City Council on this project, providing the strength, flexibility and water resistance qualities required to ensure a long lasting reinstatement. These qualities alongside the self-compacting nature of the material and quick curing time meant the installation process time was greatly decreased creating a far less disruptive installation.
Such was the success of this 2.1km phase of the project, that a further 10km of cable has subsequently been installed utilising the same methodology.