Supply Chain - Site Preparation - Retaining Walls

In the Norfolk seaside town of Great Yarmouth stands Grist Mill. Dating back to the late Victorian era, the building is of local historical significance and stands directly alongside the western bank of the River Yare in the Cobholm Island area of Great Yarmouth. The existing quay wall and apron had deteriorated to a quality where it provided little, if any protection to the foundations of the timber framed Grist Mill, so the services of Ivor King were engaged to install a new sheet pile flood defence around the building. The works were part of wider £42.5 million Environment Agency Tidal Defence Initiative in the area to protect against the threat of East Coast flooding in the Norfolk seaside town. We carried out a virtually silent and vibration-free installation into hard ground to form a three-sided cofferdam waterside to the building, ensuring its future longevity. The Challenge The mill, located directly next to the River Yare, three miles up from where it flows into the North Sea, is set in a residential area, with neighbouring properties in close proximity. In addition, 23.5 metre ‘Z’ section steel sheet piles would need to be delivered into site and passed over the three-storey building in pairs for installation into hard ground conditions. The Solution Giving consideration to the impact of works on the local neighbourhood, along with the fragile nature of mill’s foundations and its environmentally sensitive riverside setting, our Giken Supercrush solution was selected as the only truly viable way of meeting all challenges. Supercrush is an extension of the Giken silent and vibration-free installation method, whereby sheet piles can be pressed into the ground without causing noise or vibration, whilst also overcoming hard ground conditions by simultaneously augering the ground during the installation process. Equipped to deliver Delivering the 23.5m long (more than twice the length of a London bus) sheet piles into site in pairs was facilitated by Ivor King’s in-house transport team. The route in (the last part being particularly challenging – narrow and twisty) was meticulously planned and deliveries were carried out using our special extendable rear-steer trailer, specifically designed for transporting long loads into sites with limited access. Two 300 tonne Liebherr Crawler Cranes were used for the lifting operations. One to manoeuvre the collosal sheet piles over the three-storey building in pairs and into the chuck of the Silent Piler. Another to steady the Supercrush auger (necessary due to the hard ground conditions), itself standing some 30 metres tall and weighing circa 30 tonnes, during the piling process. Using reaction force, each pair of ArcelorMittal AZ40-700 sheet piles, up to 23.5m in length, were installed by one of Ivor King’s mighty Giken ‘Double-Crush’ Silent Pilers, which clamps onto previously installed sheet piles and is capable of ‘walking’ along the piles to travel forward.

Vibration-free installation of cofferdam - Courtesy of Ivor King - The Piling People

Respecting the environment Further to our environmentally friendly installation technique, compressed air was used to create a bubble curtain, (sometimes known as a pneumatic barrier) to obstruct silt caused by augering from escaping into the flow of the river. Following sheet pile installation, wailing and capping beams, plus anchor ties were added to increase the integrity of the structure, ready to accept a concrete slab to complete the upgrade to the mill’s foundations. Client: JN Bentley on behalf of Environment Agency Project cost: c. £1.7m Completion date: October 2022  Project period: 19 weeks Plant utilised: Giken SCZ675 'Double Crush' Silent Piler 300T Liebherr LR1300 Lattice Boom Crawler Cranes Broshuis Rear Power-Steer Triple Extender Trailer The specialist silent and vibration-free piling technique provided by Ivor King and their Giken Supercrush helped us deliver our objective of better protecting the people and property of Great Yarmouth from flood risk whilst overcoming the challenges of working in a very residential area, within meters of a locally significant building and on the edge of the environmentally sensitive site of Breydon Water. Thanks to Ivor King for their support of JBA Bentley in delivering this project. Tom Stanley, Environment Agency Project Manager

When you’re installing sheet piles at the end of a residential cul-de-sac, next to an adjacent river, your installation method needs to be silent, vibration-free and environmentally friendly. Add hard ground conditions into the mix and you’re going to need our Giken Supercrush solution. Lady’s Walk is a picturesque footpath on the bank of the River Wansbeck in Northumberland, connecting Morpeth town centre with the nearby village of Mitford. During the rainy Easter weekend 2018, 35m of river retaining wall and footpath subsided and fell into the river.Northumberland County Council engaged the services of Ivor King to install a sheet piled retaining wall in to order to stabilise the land, enabling necessary repairs to be carried out and ultimately for the public footpath to be reinstated. Challenges & Solutions Hard ground conditions, environmental issues and extremely restricted access made this project particularly complex; site access was via a 3.2m wide residential cul-de-sac, with neighbouring properties within close proximity and an environmentally sensitive riverside location. Using Giken Supercrush technology, we were able to overcome hard ground conditions, whilst pressing-in piles using silent vibration-free methodology. This ensured minimal impact to residents in neighbouring properties as well as protecting local flora and fauna in and around the adjacent river. (Note: in the video below, pay special attention to the group of ducklings swimming past undisturbed, oblivious to the installation, proving our Giken solution really is silent and vibration-free!)

Riverbank sheet piling to enable reinstatement of public footpath - Courtesy of Ivor King - The Piling People

Furthermore, the expertise of our in-house transport team was called upon, with all deliveries were meticulously planned and executed by Ivor King Transport into a site where access was extremely tight and barely wide enough to accommodate an articulated lorry. Once our sheet pile retaining wall installation was complete, repairs could take place to the the riverside path with eventual reinstatement and reopening of this popular walking route in Northumbria. Location: Lady's Walk, Morpeth Client: Northumbrian County Council Project cost: c. £269k Completion date: November 2018 Project period: 8 weeks Plant utilised: Giken Supercrush Silent Piler JCB JS360 Excavator with Side Grip Movax Attachment Marchetti Crawler Crane

The Lincoln Defences Project is a £6 million investment led by the Environment Agency to improve the city’s flood defences for around 4,000 homes and businesses. As part of the scheme, we installed a total of 340 linear metres of steel sheet piles up to 9.5m in length on a stretch of the Sincil Dyke in Lincoln for bankside stabilisation works. Challenges & solutions The close proximity of residential properties meant the Giken silent and vibration-free method of installation was required. In fact, sheet pile installation happened mere metres away from the houses and gardens of neighbouring properties, which were directly in front of and parallel to the watercourse where works took place. For extra efficiency, two Siken Silent Pilers were set up to work in tandem, installing piles synchronously either side of the dyke. Heavily restricted access at this site required supporting ancillary equipment and power packs to be accommodated directly behind the Silent Pilers on modular steel platforms, sitting atop previously installed sheet piles. As the Gikens ‘walked’ along the pile line to their next positions, so the crane mats and equipment were moved along in a direct line with them.

A vibration-free installation into hard ground close proximity to residential properties - Courtesy of Ivor King - The Piling People

It was also necessary to access the far end of the site through an existing warehouse building. To overcome low headroom, a tractor and trailer assisted with the movement of plant and equipment through the building, including a 90T crane needed to pitch piles, which also had to be broken down into modular form. The crane was then rebuilt once through the warehouse building, ready to support piling works. Due to hard ground conditions the two Gikens operated in Supercrush mode, where the ground is pre-augered as piles are simultaneously pressed-in. Because Giken technology is virtually silent and vibration-free, disturbance and disruption to the daily lives of local residents during works was able to be kept to an absolute minimum – a key requirement on this project. Location: Minworth, Sutton Coldfield Client: JN Bentley on behalf of Environment Agency Project cost: c. £1.1m Completion date: December 2021 Project period: 16 weeks Plant utilised: 2 x Giken ECO700S Silent Pilers in Supercrush mode 2 x 90T Lattice Boom Crawler Cranes 35T Excavator Tractor & Trailer

Curdworth Lagoon is located within Minworth Sewage Treatment Works next to the River Tame. Ivor King - The Piling People was asked to design a solution to retain and stabilise the lagoon embankment, whilst protecting against erosion from the adjacent river. Due to the risk of landslip coupled with adverse ground conditions, we deployed Giken Supercrush technology using one of our ECO700S Silent Pilers. This ensured we could overcome hard ground conditions whilst using a silent and vibrationless, environmentally sensitive method of installation. The operation was supported by AGD Equipment’s Giken clamp crane, due to a narrow corridor of working which prevented the use of piling mats. Ivor King are the only owners of Giken Supercrush Silent Piling Technology in the UK and the largest in Europe.

Curdworth Lagoon Embankment Stabilisation - Courtesy of Ivor King - The Piling People

The resultant pile line spans almost half a kilometre, comprising 750Nr PU28-1 steel sheet piles ranging from 7 to 11 metres in length, complete with weep holes at regular intervals to overcome ground water pressure over the retained height. The method of installation proved to be so efficient, we delivered the project four weeks ahead of schedule, giving considerable savings on programme time to the client. Sheet piles were mobilised to site using a tractor and bespoke trailer due to weight restrictions which precluded Heavy Goods Vehicles. Location: Minworth, Sutton Coldfield Client: Costain Project cost: c. £1.4m Completion date: October 2018 Project period: 16 weeks Plant utilised: Giken ECO700S Supercrush Silent Piler IHI 70 tonne Lattice Boom Crawler Crane Giken CB2-5 Clamp Crane Tractor and bespoke trailer by Ivor King

Along the tidal estuary of the River Crouch in Essex, a 40 metre length of embankment had slumped at Hullbridge, requiring repairs to damage caused by the tide. Ivor King installed over 100 permanent steel sheet piles to form an ‘anti-slip circle’, which also provided a safe working environment for repairs to take place in the form of a cofferdam. Overcoming limited access and tidal flow Landward access to the site was not possible due to the close vicinity of neighbouring properties. Owing to their close proximity, the solution had to be silent and vibration-free to limit disturbance, whilst also overcoming challenging ground conditions. In addition, the work area was subject to tidal flow, which necessitated a jack-up barge to be deployed for piling operations to be carried out. A jack-up barge is a floating platform with movable legs which can be lowered into the sea bed. The legs anchor the barge so that the platform can then be ‘jacked up’ to clear the waterline, counteracting any movement caused by tides and passing vessels. The only viable installation method that satisfied all criteria was Giken Supercrush – a vibration-free piling technique used for hard ground conditions, whereby augering takes place at the same times as piles are being pressed-in. The Giken Silent Piler uses reaction force to install piles. However, working from a jack-up barge meant the initial reaction piles could only be installed by welding the Giken reaction stand to the platform of the barge. Once the starter piles were in-situ, the silent piler could carry out installation in the usual manner, clamped on top of previously installed piles.

Sheet piles installed vibration-free from a jack-up barge, on a river subject to tidal flow - Courtesy of Ivor King - The Piling People

Grouting the voids The sheet piles, up to 15 metres in length, were also grouted to seal any voids – the grout was pumped from a nearby on-shore mixing plant during periods of low tide. Once installed, remedial work could take place in safety, protected by the sheet pile cofferdam. Following the completion of works to fit new revetment blocks to the embankment, the sheet piles were cut down to form the anti-slip circle that guards against future slippage. Location: Brandy Hole, Hullbridge Client: Jackson Civil Engineering Project cost: c. £900k Completion date: November 2021 Project period: 9 weeks lant utilised: Giken F301 Silent Piler operating in Supercrush mode