Kent County Council in the UK is building a new section of road on the outskirts of Sittingbourne in south-east England, which is aimed at removing congestion in the town centre and improving access to the existing Eurolink Business Park and East Hall Farm housing estate. The single carriageway Sittingbourne Northern Relief Road will link and connect to the existing Swale Way distributor road that joins the A249 dual carriageway to the north of the town and to the existing Eurolink and East Hall Farm road to the south.
Aarsleff Ground Engineering were awarded the US$1.2 million contract to supply and install the 350mm square section piles. The piling contract also included some trial piling and static and dynamic load testing to confirm and corroborate with the design.
Aarsleff used two of its own piling rigs on the project with the smaller Banut 700, equipped with a free fall drop weight, working on part of the northern section of the embankment. It had to drive about 240 of the shorter piles, all 11.5m long and predominantly in rows of 23 on an approximate 2m grid. The company’s largest Junttan PM26 LC worked on the southern section installing around 1,250 of the longer piles up to 17.5m. These are in rows of seven and on a larger 3m grid pattern. The PM26LC, with an accelerated impact hammer, has an adjustable stroke of up to 1.2m. It is operated from the rig’s hydraulic system and hydraulically accelerates the drop weight during the fall, boosting the impact energy and increasing by up to 20% the efficiency at full stroke over a conventional free fall drop hammer of the same weight. The hammer with its heaviest 9t weight produces maximum impact energy of 106kNm at full stroke. Impact energy, stroke and blow rate can be infinitely adjusted by the rig operator to suit ground conditions and pile type, as the accelerated hammer is suitable for driving all types of precast concrete, steel tube, sheet and timber piles.Download Case Study