This project was contracted to VBA, a joint venture comprising VolkerStevin, Boskalis Westminster and SNC-lavalin’s Atkins business on behalf of the Environment Agency. The scope of work includes the design, construction and installation of a 20m wide tidal barrier gate, construction of piled flood defence walls on either side of the barrier, a MEICA control building, the installation of mechanical and electrical equipment, flood gates on the east and west banks within the flood walls, scour protection and landscaping works.
Ipswich has a long history of flooding both from high fluvial flows and surge tide effects, the new tidal barrier gate is designed to prevent surge tides and allow control of fluvial flow downstream, providing enhanced flood protection to more than 1,500 residential and 400 commercial properties within the risk area.
Sword was awarded a sub-contract which included:-
- The construction of the reinforced concrete structure to accommodate the rolling sector gate – which comprised a base with east and west piers
- Supply and installation of formwork, falsework and consecutive pours
- The installation of low tolerance inserts
This project was not without its challenges given the size, scale and radius of the base pour, which required a radius shutter to form a recessed cell within the base of the structure to accept the rising sector gate.
Whilst the formwork designer was able to provide a rigid profile for the temporary works – to eliminate any possibility of an uplift under the huge force of the self-compacting concrete, another company was brought in to provide an injectable adhesive product for the holding down of the temporary works system.
The installation of the temporary works came with its own challenges, particularly as the numerous components had to be installed within low tolerance levels to ensure design compliance.
The temporary works were not the only challenge, given the complexity of the radial design, this also required an innovative approach to the permanent works.
Once permanent and temporary works were in place, Sword planned and placed the specialised concrete into the base pour and through careful monitoring by Sword and the VBA team, the base pour was completed successfully and to the Environment Agency’s satisfaction.
Given the unique and challenging nature of this project for Ipswich, Sword takes great pride in having taken part in its successful completion.
(Images courtesy of Environment Agency)