Case Study Overview
Sladdens Pier in Lowestoft is over 100 years old and provides protection for the Trawl Dock at the Port of Lowestoft. To protect both the structure and the Trawl Dock, Red7Marine carried out the construction of a new river wall in front of the offshore face of Sladdens Pier, providing ABP with security and greater longevity for their structure.
Red7Marine developed the scheme with its chosen designer, Robert Leeds Structural Design, since late last year, with work on site commencing August 2023.
At a glance
- Location: ABP Sladdens Pier, Lowestoft
- Plant used: 250T Haven Seariser jack-up barge and Haven SeaStabler
- What we did: Red7Marine was contracted to complete a £2M design and build project for Associated British Ports for the construction of a new river wall in front of Sladdens Pier in Lowestoft
CHALLENGE
Red7Marine’s 250t deck capacity Haven Seariser 3 jack-up barge carried out a proof dig in September 2022 at the design locations of the pile wall. The barge was equipped with a 35t excavator from W M Plant Hire. The team carried out two dive surveys and extensive digging, several timber piles were removed as well as concrete and metal. All design sheet pile locations were also probed to highlight that the sheet piles could be installed safely and without risk of obstruction.
Following the final proof dig and dive survey, Red7Marine began piling activities.
SOLUTION
Piling activities comprised of a continuous sheet piled wall formed using approx. no.100 sheet pile pairs spanning a length of 140m.
To carry out the piling activities, Red7Marine utilised its Haven SeaStabler as a flat top barge and the Haven Seariser 3 jack-up barge.
Both barges and a piling gate were secured and fixed into position in each pile location. Piles were lifted from the flat top material barge into the piling gate on the jack-up barge, and then were vibrated into the riverbed using a variable frequency piling hammer, this allows for a slow start method, which is a requirement for ecological preservation.
Pile installation progressed from north to south and required several barge moves in total on the northern side of Sladdens Pier. The barge was also positioned on the inside of the Trawl Dock for the final section of pile wall to reduce impact on the main navigational channel into Lowestoft. When all sheet piles were installed to design level, capping beams were installed across the top of the driven sheet pile wall.
The project was delivered successfully on time and within budget. Rob Page, Project Manager at ABP comments: “Really pleased with the overall product and how Red7 worked with ABP to deliver this project. Would have no hesitation in using them again.
