Silvertown Tunnel new north bank river wall

THE BRIEF

The Riverlinx Joint Venture was required to construct a new river wall along the north bank of the River Thames comprising a tied sheet pile intertidal wall; a precast concrete flood wall; and an intertidal terrace. The works provide 340m (out of approximately 1km of new flood defences) being constructed as part of the wider Silvertown Development Plan.

The brief included requirements to prepare a design capable of construction from land-based plant within a range of site-specific constraints. A section of the wall passes over the new tunnel bores limiting penetration of piles; the wall needs to retain stability during the tunnel boring; flood defence levels need to be maintained at all stages of the construction; a design life of 120 years is required, and compliance is needed with the consent obtained from the various Regulatory bodies.

VALUE-ADDED SOLUTION

RWC worked with the Riverlinx team to develop a scheme design and construction sequence which enabled all construction works to be delivered from landside construction plant whilst maintaining the flood defence. This required a phased sequence for installation of new anchors and removal of existing anchors. RWC assessed the existing river walls for the loads imposed by the construction plant and developed a 3D model to define interfaces between the new and existing river walls.

RWC split the 340m of new flood defences into bays to support the construction programme. RWC designed and assessed the new flood defence structures for the impact of the tunnel boring machines, constructing the new twin bore tunnels, after installation of the first bay of the new river wall. RWC defined the required monitoring regime for the existing and new flood defences throughout the construction and tunnelling phases.

RWC liaised with the wider Riverlinx project team, including other design parties and the various River Regulators. RWC supported Riverlinx in obtaining and discharging consents from the various Project Stakeholders (including TfL) and the River Regulators. This included undertaking damage assessments of third-party assets including the foundations to the Emirates Airline Cable Car and various Thames Water Assets.

FINAL OUTCOMES

Construction of the project commenced in Autumn 2021 and is programmed for completion in late 2022. The Works have proceeded on site as planned and RWC have provided construction support to the Riverlinx team and to the supply chain for sheet piling and precast concrete