Case Study Overview
Red7Marine supported the Marine and Civil Services / GPS (MACS / GPS) joint venture on work to strengthen Southend Pier ahead of construction work for a new public toilet block being built. The project is being carried out on behalf of Southend-on-Sea Borough Council and is a part of the £2.5million capital investment into Southend-on-Sea’s pier head, following engagement with residents and visitors.
At a glance
- Location: Southend-on-Sea Pier
- Plant used: Haven Seajack 2 100t jack-up barge
- What we did: Red7Marine supported the Marine and Civil Services / GPS (MACS / GPS) joint venture on work to strengthen Southend Pier ahead of construction work for a new public toilet block being built.
To support the project, MACS / GPS chartered Red7Marine’s 100t deck-capacity jack-up barge, the Haven Seajack 2. The barge was used as a stable platform for the installation of new support piles and steel beams, and bracing, to provide additional support for the pier structure.
This was one of the most challenging locations we have ever had to mobilise a jack-up barge due to the lack of accurate geotechnical and environmental data available. Whilst completing a Site-Specific Assessment for the project, our team found some data which suggested reasonably firm clay at the surface, whilst others stated a rather deep layer of silty clay with limited properties in regard to its ground bearing capacity. There was also evidence of a sand layer at a depth of around 10-13m deep, followed by further clay, presenting a risk of punch-through. Risk of scour was assessed but due to the expected depth of penetration, the risk was considered as low. However, having significant penetration into clay, produced a risk during extraction of the legs.
We had initially assessed using our Haven Seaway jack-up barge due to its larger deck capacity, however after conducting a Leg Penetration Assessment (LPA), a high risk of punch-through was identified due to a layer of loose sand within the clay layer. If the legs were to penetrate through this sand layer, then there would be insufficient leg length to get the barge to a safe height. To overcome this problem, Red7Marine performed an LPA for the Haven Seajack 2, with a lighter deck load, there was less penetration. While the risk of punch-through remained on the low bound assessments, the leg length stayed above the operational limits of the barge. To best reduce risk during the event of punch-through, cyclic preloading techniques were adopted and all vibro piling operations were to be restricted if used.
The Haven Seajack 2 successfully completed the operations and received leg penetrations as predicted, a result of the due diligence taken by all parties throughout the planning phases of the project. The structural support work was completed ahead of the main construction programme to install new public toilets, to replace the original block which was destroyed by a fire in 2005. The new block will also include an estuary viewing platform on the floor above. The toilet block is one of several initiatives taking place to improve the pier.
Southend Pier has remained open to the general public as normal throughout the operations, with the majority of the work being carried out in the early morning to cause as little disruption and noise disturbance as possible.
SEE RELATED CASE STUDIES
Westminster Pier Extension
The Westminster Pier Extension allows more frequent River Bus services between Woolwich and North Greenwich to Westminster. The extension is a key part of the River Action Plan to improve TfL’s piers and increase capacity for passengers before 2020. Red7Marine designed and built a custom pile gate for the project. The barge was reviewed to support a 180t crawler crane for piling operations and was then further reviewed with an additional RH28 drill rig on board.
In order to accommodate a new luxury apartment block in Brighton, part of the marina needed to be reclaimed using sheet piled cofferdams. This would enable the water to be kept out and foundations to be built for the stunning seafront properties. Red7Marine supported the installation of a sheet pile twin wall cofferdam.
Red7Marine installed replacement Active Effluent Discharge Lines at Oldbury power station as part of the on-going care and maintenance works. Red7Marine’s previous project experience on similar projects consisting of works on subsea pipeline and outfalls at Bradwell and Sizewell nuclear power stations, positioned the company as the ideal marine partner for client, Magnox.
Emirates Cable Car
The Emirates cable car was installed to provide a pedestrian link across the River Thames between the Royal Docks and the Greenwich peninsula. Red7Marine worked with Bachy Soletanche in a joint venture to install the foundations for the one-kilometre long cable car using marine rotary bored piling.
Middleton Sands Navigation Marker
This fast turn-around marine construction project involved the installation of a new tubular steel navigation marker pile at Middleton Sands, Barrow-in-Furness in 2017. The navigation marker was required to identify the sub surface obstructions and enable other vessels in the area to operate safely.
Liverpool 2 Deep Water Port Extension
Red7Marine was the marine partner of choice for BAM Nuttall when they constructed a piled combi-wall as part of the Liverpool 2 Dock Expansion that began in 2014. The construction of the container terminal was supported by four of Red7Marine’s jack up barges; the Haven Seariser 1, Haven Seariser 2 and the Haven Seariser 3 and the Haven Seajack as it carried out rock socket piling works.
The Red7Marine team was chosen to provide specialist marine plant and personnel to aid the redevelopment of the Weston-super-Mare Grand Pier after it was destroyed in a fire in 2008. Red7Marine supplied the Haven Seajack 4 assisted in the pier construction works. Its previous experience in pier and marina construction works made it the ideal project partner for this development.
Bradwell Power Station Barrier Wall Removal
Red7Marine is a leading provider of equipment for marine demolition and is skilled in dismantling structures that are beyond the reach of ordinary demolition contractors. In 2012, Red7Marine removed approximately 800 tonnes of steel in the Blackwater Estuary from the Bradwell nuclear power station water intake structure.
Fingringhoe Firing Ranges
Red7Marine installed scour protection and provided remediation on damaged sections of the flood defences to preserve areas of the salt marsh at the Fingringhoe firing ranges in Essex. Scour protection and remediation techniques are used to control erosion in both estuarine and the offshore environments.