Description of the goods or services required
The Thames Tideway Tunnel project (the Project) will control CSO discharges by intercepting and diverting combined sewage flows into a new storage and transfer tunnel. The main tunnel will run from Acton Storm Tanks in west London to Abbey Mills Pumping Station in the east, where it will connect to the Lee Tunnel, which will transfer the combined sewage to Beckton Sewage Treatment Works for treatment. The Project extends from Acton Storm Tanks in west London, to Abbey Mills Pumping Station in east London. The Project includes associated works at Beckton STW, Shad Thames Pumping Station and Bekesbourne Street.
The Project comprises:
i. a main tunnel which will capture and store combined sewage from CSOs along its route and transfer it to Abbey Mills Pumping Station, from where the Lee Tunnel will transfer it for treatment at Beckton Sewage Treatment Works
ii. 11 connection tunnels, which will link flows from CSOs to the main tunnel.
i. five main tunnel Worksites (drive and/or reception sites)
ii. 16 CSO Worksites
iii. two System modification Worksites Thames Tideway Tunnel
iv. works at Beckton Sewage Treatment works.
Section 4: Scope of Works
Construction of a secondary lining to a 30m dropshaft, casting of the vortex drop tube, and internal walls at Acton Storm Tanks. The site is situated in Ealing, West London. These works are to run concurrently with other BMB areas of works including hydraulic structures works. Full welfare facilities will be provided to all subcontractors.
The scope of works includes supply of concrete and provisions of which to carry out the secondary lining. This will require consideration for sequencing alongside the site wide programme. The slipforming operation will be given priority for logistics and laydown areas during this time.
The subcontractor will have to take into consideration ducting (condensation drainage and ventilation ducting) that enters the shaft is required, including but not limited to waterproofing detail and casting in.
The Subcontractor shall be responsible for design and supply of any temporary works slipform shutter required for construction of the secondary lining of the shaft, baffle walls and casting in the vortex drop tube structure.