In December 2014 VolkerStevin was appointed by Thames Water to carry out enabling works, ahead of the Thames Tideway Tunnel construction, which will tackle pollution in the Thames.
VolkerGround Engineering was awarded a £1.5m sub-contract by VolkerStevin to install sheet and tubular piles to enable the construction of new berthing facilities for permanently moored vessels, allowing access for the main tunnelling works.
At Blackfriars pier, VolkerGround Engineering installed 123 linear metres of AZ 28-700 piles, 17 metres in length, parallel to the existing bank to provide facilities for the new pier landing pontoon. The team also installed tubular piles, up to 35 metres in length, to provide mooring points for The President vessel, adjacent to the relocated pier.
On the Victoria Embankment Foreshore, VolkerGround Engineering installed 95 linear metres of sheet and tubular piles to provide new mooring facilities for the Tattershall Castle, a decommissioned steamer that is now a popular destination for city dwellers.
In order to gain access to the riverside locations, plant was operated from a floating barge. This provided a challenge to the site team as timing of barge movements became a critical factor. Occasionally it was necessary to suspend operations due to the wake caused by passing vessels.
The soils, typical of those within the Thames Basin, comprised variable gravels overlying stiff clays. This meant that impact driving was required. To combat noise levels in this busy part of Central London, the VolkerGround Engineering team used a combination of crane suspended vibratory hammer and shrouded impact hammer to drive the sheet piles to the required design levels, through traditional temporary piling gates, installed prior to driving.
A key part of the six-month early contractor involvement phase was to develop methodology which minimised disruption to the river users, mitigated noise and vibration concerns and utilised the river for deliveries to reduce road congestion.
Working hours were also adapted in consideration of performances at the nearby Globe Theatre and to avoid noise during exams at an adjacent school.