Commercial Marine & Piling busy on the Thames

CMP have provided a progress report on construction of the 350m long outfall at Beckton sewage treatment works east of the Royal Victoria Dock and London City Airport. The project is part of the Thames Tideway Tunnel for Thames Water and CMP’s work includes design and construction of the twin bore 3m diameter pipes. The value of the total package is reported as £12.6m and the work includes installation of over 11,000m2 of steel sheet piling to allow dredging of the river bed, an operation that will see over 26,000m3 of riverbed material being removed. Part of the engineering work will involve re-using around half of the materials to backfill the pipes once installed: this allows an environmental advantage to be gained by vastly reducing the materials required to be removed from the site. The pipes (pre-fabricated from HDPE in strings of lengths up to 100m) are lifted into the water with special caps in each end, the pipes hollow box construction allowing the box to be filled with grout to add ballast. The next phase involves the first pipe section being towed to site and sunk into a cofferdam where divers will bolt the flanges to the next section. One hundred tonne concrete blocks will then be cast underwater to help anchor the pipe.

In the second announcement, CMP revealed that they have acquired a wharf at Thameside Quay in Northfleet, upriver from Gravesend and opposite Tilbury. The River Thames Wharf will provide CMP with a 240m long marine base providing an ideal location from which to mobilise and coordinate marine construction works along the river as well as providing convenient access to the south coast of England and continental Europe. The wharf has a heavy duty quay that allows loading of marine plant and equipment and the base has been used by the company for over 40 years facilitating marine construction projects such as the London Cable Car crossing, Blackfriars Bridge and the Thames Barrier.

By Peter Barker