Water Street Bridge

KEY FACTS

LOCATION: Wood Wharf, Canary Wharf
CONTRACTOR: Canary Wharf Contractors Ltd
CLIENT: Canary Wharf Contractors Ltd
VALUE: £7m
SECTORS: Major projects and infrastructure, Commercial, mixed use, residential and retail
SERVICES: Construction and Civil Engineering

The project entailed the construction of the Water Street Causeway and both bridge abutments to enable the installation of a single leaf bascule bridge connecting Montgomery Street and Wood Wharf.

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Constructing the East Abutment, a partially submerged concrete box housing mechanical elements for the bascule bridge, was significantly challenging. The initial options considered were not viable as the structure came within 2 metres of the London Underground Jubilee Line exclusion zone. Following discussions with the client, the agreed final solution was developed utilising techniques and products from a variety of civil engineering industries.

All of the temporary works on the project were designed, detailed and fabricated in-house by Kilnbridge to ensure seamless quality control and minimise interfaces on site in order to maintain safety and environmental excellence. A steel grillage was installed onto the permanent casings of the marine piles installed previously by Bachy Soletanche, which incorporated a steel deck to act as a working platform and ‘grout cans’ housing fabric grout bags to provide a seal around the permanent piles. This was then covered in a 120mm thick concrete watertight base slab to allow for the construction of the permanent external concrete walls and central dividing walls poured at half thickness.

Once in place, a further level of steel platforms were installed to support the strand jacking equipment onto the permanent pile casings. The 460t box was then lowered more than 4m below the dock water level into its permanent position, allowing the section to be sealed and dewatered with temporary brackets providing resistance to the uplift of 180t of water. The permanent base slab and walls were then installed to release the temporary works and provide a permanent safe working platform to allow the completion of the East Abutment FRC works.

For the Water Street Causeway a hybrid concrete solution was sought, with the finished Reckli Edge Panels split into two sections to suit the challenging logistics. Manufacturing the precast sections off-site was generally not feasible due to their size and weight (up to 40t) so Kilnbridge set up a temporary precast yard on-site and carried out all designs, detailing and construction in-house. The concrete sections were installed by a 160t Crawler crane tracked on a fabricated steel grillage and typically comprised of precast U-beams, precast planks, precast split edge beams and in-situ toppings to tie all elements together.

Kilnbridge won the Temporary Works Initiative of the Year (Civil Engineering) award at the 2018 British Construction Industry Awards for this project. The judging panel commented that it “involved a high-class solution that was better than the original concept design."