Rother Tidal Walls East Flood Defence Scheme
Throughout April and May 2024, the VolkerGround Engineering team were on site in Rye, East Sussex. Supporting VolkerStevin with a scheme to raise and strengthen the existing flood embankments between Scots Float and Rye Harbour, on the eastern bank of the River Rother.
The scope of works was to install 358, 4.7m long AZ20-700 steel sheet piles, along 240 linear metres of embankment.
At certain points along the embankment, the width was only 2.5m which meant an alternative solution had to be developed in terms of the site and type of plant required to install the piles. A spider excavator does not require a substantial granular working platform due to the use of the articulated wheels, so this was considered the most suitable option.
The spider excavator, fitted with an auger dangle drill, enabled the team to pre-auger the pile line to locate and move high level obstructions envisaged in the made ground. VolkerGround Engineering faced several challenges in the delivery of this scheme. In particular, the very narrow site entrance required the piles to be brought to site on rigid wagons rather than articulated trailers. The piles were distributed to the working area on a battery operated radio controlled tracked carrier, aided by track mats laid on top of the embankment which provided a clean level working platform for the carrier to travel along.
For future raising of the flood defences, a steel capping beam rather than a concrete capping beam was suggested by VolkerGround Engineering’s Pre-Construction team. This, together with the use of the spider excavator, provided a CO2 saving of 272T.
The project scored an impressive 48/45 in a Considerate Constructors Scheme audit, and VolkerStevin was awarded a £30k Carbon Net Zero Grant to assist with innovation.
Benefits of the Spider Excavator:
- Reduced temporary works – less cost, carbon, duration, safety risk and environmental impact
- Reduced interface and land purchase from adjacent landowners
- Greater flexibility on access and construction sequence
- Ability to multi-task: a quick change of attachment allows excavation and auguring thus reducing the impacts of obstructions and vibration
- Ability to install sheet piles in places unreachable by conventional piling plant.
