M28 Cork to Ringaskiddy Advanced Works

• The works were successfully completed in close proximity to a 325mm high-pressure gas main and fibre optic cables, which were protected using steel plates.

• An innovative, gravity-fed diversion eliminated the need for wastewater pumping, significantly reducing project risk.

• The defunct pipeline was decommissioned by filling it with air-entrained concrete to remove subsurface voids.

Materials Used:

• 285m of 1500mm DC4 sulphur-resistant concrete pipe.

• 80m of 450mm and 15m of 300mm DC4 sulphur-resistant concrete pipe.

• 25m of 1200mm ductile iron pipe (Saint Gobain), installed beneath a high-pressure gas main using Viking couplers.

• Six DC4 concrete manholes (three 4m and three 3m) with sulphur-resistant benching.

• PCL eliminated the need for overpumping and standby pumps by using an existing manhole as a temporary reservoir, allowing treated water to flow downstream by gravity.

• During excavation, PCL reduced the ground level by up to three metres, which removed the requirement for extensive shoring.

• To mitigate the long lead times for key pipework, PCL established a site compound to stockpile materials until a sufficient quantity was available to complete the works.