Tideway takes delivery of final NEC-procured TBM

Tideway, the company delivering the £3.8 billion Thames Tideway Tunnel in London, UK, took delivery of its sixth and final NEC-procured tunnel boring machine (TBM) in July. Worth an average of £15 million each, all six machines were purchased using NEC3 Supply Contracts (Issue 103).

The 8.8 m diameter slurry TBM Selina was one of three supplied for the 25 km long, 35–65 m deep ‘super sewer’ project by Herrenknecht in Kehl, Germany. It was delivered to Tideway’s Chambers Wharf site on the south bank of the Thames in Bermondsey after an 800 km journey by river and sea.

Later this year Selina will start tunnelling the 5.5 km east section of the sewer between Bermondsey and the already-built Lee Tunnel, which links Abbey Mills pumping station to Beckton sewage treatment works. The main contractor for this section is CVB, a Costain, Vinci and Bachy Soletanche joint venture working under an NEC3 Engineering and Construction Contract Option C (target contract with activity schedule). Herrenknecht has already supplied the earthpressure-balance machines (EPBM) Rachel and slurry TBM Annie, which are driving the 7 km west section and 4.5 km Greenwich connection respectively. NFM Technologies in Le Creusot, France supplied the EPBMs Millicent and Ursula working on the 12.6 km central section, while Morgan Sindall in Staffordshire refurbished the 

Lovat EPBM Charlotte that has just completed the 1.1 km Frogmore connection.

 
Critical packages

The TBM supply contracts were all classified as critical packages, which means they had critical importance to successful achievement of the project’s objectives. They were also defined in the main NEC3 ECC Option C works contracts as ‘key subcontracts’, requiring the contractors to seek 
the project manager’s acceptance prior to issuing tenders or appointing suppliers.

According to Tideway programme director Andy Alder, ‘The use of the NEC3 Supply Contract on Tideway for the TBM procurement has been very effective, with the flexibility to tailor the contracts to meet project needs. This included accommodating the logistical complexities of transporting TBMs over 100 m long from Europe to the heart of London, as well as removing the financial risk from suppliers prior to delivery. ‘It has been demonstrated on Tideway that the NEC3 Supply Contract encouraged the right philosophy to deliver these high-risk, highprofile subcontracts collaboratively and therefore efficiently. NEC’s use of simple English has supported its application for the procurement of the TBMs with international suppliers without the need of costly legal intervention.’