Shani Wallis, TunnelTalk

Expressions of interest are called this week for the two large tunnelling contracts that will form the core of London's Crossrail project under the heart of the capital.

Contract C300 comprises the 6.2km section of twin tube 6.2m diameter running tunnels from the Royal Oak Portal west of Paddington Station through to the new Crossrail station at Farringdon.

Contract C305 covers the 8.3km of twin bored tunnels from a launch chamber at Limmo Peninsular east to Farringdon Station, with a launch chamber at Stepney Green for a 2.7km long drive through to the Pudding Mill Lane Portal, and another launch chamber at Limmo Peninsular for the 0.9km long drive through to Victoria Dock portal.

Construction of the portal structures at Royal Oak, Pudding Mill Lane, and Victoria Dock will be under separate contracts.

Crossrail's central underground route

Award of contract will also trigger design and construction by the successful contractors of a tunnel segment manufacturing facility at a site to be designated by Crossrail. Contract C300 is expected to require two EPB TBMs for its Drive X, while the larger contract C305 will need four EPBMs completing the forked alignment with two TBMs working from Limmo Shaft to Farringdon Station (Drive Y) and two excavating the twin drives from Stepney Green Shaft to Pudding Mill Lane (Drive Z) and then from Limmo Shaft to Victoria Dock Portal (Drive G). The final drive, Drive H, is the twin tunnel connection under the Thames from Plumstead Portal to North Woolwich.

The deadline for submitting expressions of interest for this combined 18km of twin tube tunnelling, out of a total 21km needed for the overall project, will close midday Monday, 28 September. Invitations to tender are scheduled for November with contract awards by mid-2010. The first of the TBMs to excavate the under-city link is expected to launch in late 2011.

Several domestic firms and international contractors from as far a field as China are known to be interested in bidding the work on Crossrail. One international group that has declared its joint venture arrangement to bid the tunnelling contracts is the consortium comprising some of Europe's largest tunnel construction companies in Balfour Beatty (UK), Beton- und Monierbau (Austria), Morgan Est (UK) and VINCI Construction (France). On announcing the JV, BBMV's bid director Peter Mason said: "The BBMV partners and their supply chain have been selected to provide the best value to Crossrail and to give the confidence that this scheme can be delivered to time and budget."

In their lists of previous experience the BBMV partners inlcude EPB tunnelling and SCL (NATM) contracts for the East London Line Extension, the T5 rail and road tunnels at Heathrow airport, the DLR Woolwich Arsenal Station Extension, the A3 Hindhead road tunnel, the CTRL North Downs high-speed rail tunnel in Kent and the Thames Water Ring Main.

Once awarded, the successful contractors will contribute to construction planning, temporary works design and

Sizes of London's underground rail systems

constructability input into the final detailed design of the contracts prior to construction mobilization. The detailed design contracts have been awarded to Design Framework Contracts (Table 1).

Under a separate contract, C175, Capita Symonds will design a Tunnelling Academy for the project that will prepare workers for employment on the project. Up to 14,000 people are to be employed at the project's peak of construction in 2013/2015. Preparatory works will continue throughout 2009 and the project is scheduled to open for service in 2017.

In our last report the stakeholders in the project - the UK Department for Transport and Transport for London being the two largest public funding stakeholders and with private partners BAA, owner of Heathrow Airport; the City of London; the Canary Wharf Group, responsible for design and construction of Crossrail station at Canary Wharf; and Berkeley Homes, the UK house builder responsible for design and construction of the Crossrail station box at Woolwich - had all affirmed financial commitment to this £16 billion mega project. However, as the recession looks set to deepen and credit becomes increasingly hard to source, there are rumblings in corridors that a project of this size could be broken up into phases of construction rather than procurement and construction of the full project as one.

An exercise under a previous management team of the project back in the 1990s also looked at phased realization of the project, completing the core line of twin tube tunnels first, from Paddington to Canary Wharf and providing the foundation for later construction of that section's stations at Bond Street and Whitchapel. The extensions northeast to Shenfield and southeast to Woolwich and Abbey Wood could then also be built under future construction and financing phases. Construction of the Bond Street and Whitchapel stations alone would cut nearly £900 million or so from the immediate budget of £16 billion. Much depends on the UK general election next year and the efforts to limit the damaging affects of the recession and economic crisis as to the future political support and funding of the full Crossrail project.

Table 1. Design Framework Contracts awarded to date

References

Crossrail planning and mobilization to date - TunnelTalk, July 09, June 09, May 09
Crossrail website