Bidders line up to deliver Thames mega-project 30 Oct 2013
Peter Kenyon, TunnelTalk
- Sixteen contractors organised into seven joint venture teams and a single company bidder are selected to bid for design-build-maintain construction of a second and final phase of the £4.1 billion Thames Tideway mega-project. The £2.3 billion Thames Tunnel is the main element of a project designed to tackle the chronic problem of combined sewer overflows into London's iconic river.
Fig 1. Thames Tideway construction lots
Project owner Thames Water, announcing its procurement schedule for what at 25km will be the UK's largest-ever water tunnel, confirms major construction lots will be split into three main works packages valued at up to £2.3 billion (Fig 1). They are:
• West Tunnel (£300-£500 million) -
Bam Nuttall/Balfour Beatty/Morgan
Sindall JV; Costain/Vinci/Bachy JV;
Dragados/Samsung JV; Ferrovial
Agroman/Laing O’Rourke JV
• Central Tunnel (£600-£950 million) -
Bam Nuttall/Balfour Beatty/Morgan
Sindall JV; Ferrovial Agroman/Laing
O'Rourke JV; Costain/Vinci/Bachy JV;
Skanska/Bilfiger/Razel Bec JV
• East Tunnel (£500-£800 million) - Bam Nuttall/Balfour Beatty/Morgan Sindall JV; Costain/Vinci/Bachy JV;
Hochtief/Murphy JV; Bouygues Travaux Publics; Bechtel/Strabag JV
- As part of a staggered process the western lot will be tendered first, followed by east and then central. This process will be completed between November this year (2013) and April 2014, with preferred bidders due to be announced in Q2 2015. Due to the size, complexity and the high value of each of the packages JVs will be awarded a maximum of one construction lot. If bids from any of the JVs competing for the eastern or western lots fail to meet the required standard, or if any one of them withdraws at bid stage, Thames Water has put in place contracting mechanisms that will allow it to merge the affected lot with the central package of works so as to maintain a competitive process.
Fig 2. Thames Tideway shafts and ground conditions
- It is anticipated that six contractor-procured TBMs will be required to complete the project - four with an approximate cutterhead diameter of 8.1m-8.8m for excavation of the main 25km x 6.5m-7.2m i.d. tunnel, plus a small bore TBM to excavate the 1.1km x 2.6m i.d. Frogmore connection tunnel that is included in the western package and another of about 6.6m cutterhead diameter to excavate the 4.6km x 5m i.d Greenwich connection tunnel that is included as part of the eastern package. Location of the three intermediate deep-level TBM shafts at Carnwath Road, Kirtling Street and Chambers Wharf are selected to optimally split the drives according to the anticipated ground conditions of London Clay in the west, sandy ground for the central lot, and chalk in the east (Fig 2). These are in addition to deep-level shafts at the western end of the tunnel in Acton and at the eastern end at Abbey Mills Pumping Station, where a connection will be made with the currently-under-construction 6.9km x 7m i.d. TBM-driven Lee Tunnel. Preliminary design calls for a west to east slope of 1m/790m to ensure gravity flow, with underground depth ranging from 30m in the west (Acton) to 67m in the east (Abbey Mills).
The scope of tunneling works for each lot is as follows:
• West – Design, construction, commissioning and maintenance for a caretaker period of the Carnwath Road
Riverside shaft to Acton Storm Tanks main tunnel (6,950m x 6.5m i.d.) and Frogmore long connection tunnel
(1,100m x 2.6m i.d). Expected ground conditions: London Clay
• Central - Design, construction, commissioning and maintenance for a caretaker period of the westward main
tunnel drive including shafts and connections between Kirtling Street shaft and Carnwath Road Riverside shaft
(5,003m x 7.2m i.d) and eastward between Kirtling Street shaft and Chambers Wharf shaft (7,680m x 7.2m i.d.).
Expected ground conditions: London Clay, Lambeth/clay, Lambeth group and Thanet sand, chalk with sand.
• East - Design, construction, commissioning and maintenance for a caretaker period of the main tunnel drive
between Chambers Wharf shaft and Abbey Mills Pumping Station (5,530m x 7.2m i.d), and the Greenwich long
connection tunnel between Greenwich Pumping Station and the Chambers Wharf shaft (4,600m x 5m i.d.)
Ground conditions: chalk.
Herrenknecht slurry machine excavating Lee Tunnel
- Project scope also includes a number of smaller diameter connector tunnels of 350m or less to link current sewer overflows along the alignment with the main CSO tunnel which runs for the most part under the River Thames.
- "The Thames Tunnel will be the biggest tunnelling project ever undertaken in the UK's water industry," said Mike Gerrard, Managing Director of the Thames Tideway Tunnel. "We have shortlisted the contractors with the right expertise and experience who will deliver the best value for money for our customers. We are following a rigorous tender process and are confident the successful tenderers are capable of delivering the project."
- "We are building for twenty-second century London to create a cleaner, healthier River Thames. The Thames Tideway Tunnel is needed to tackle the millions of tonne of raw sewage which discharge into the River Thames every year. The river needs cleaning up and it needs to be cleaned up now," added Gerrard.
- The £635 million Lee Tunnel (Thames Tideway Phase 1), which is being excavated by the Morgan Sindall/Vinci/Bachy JV using an 8.88m diameter Herrenknecht closed-face slurry machine, is due for completion by the end of this year (2013). All three of those companies will now be bidding on one or all of the three Thames Tunnel construction lots, though not in JV with each other. A further £675 million is being spent by Thames Water as part of the Tideway Project on upgrades to five sewage treatment works.
TBMs ready for London sewerage drives - TunnelTalk, February 2012
Lee Tunnel shaft sinking progress - TunnelTalk, October 2011
TBM commissioned to tackle London CSO task - TunnelTalk, May 2011
Super sewer to revitalize River Thames - TunnelTalk, March 2009
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