The Hong Kong Highways Department (HyD) has marked 10 years of growing NEC use in the territory by letting the government’s largest NEC target contract to date.
In July this year, an NEC3 Engineering and Construction Contract (ECC) Option C (target contract with activity schedule) worth HK$6.23 billion (£660 million) was awarded to Bouygues Travaux Publics for the main tunnel section of the Central Kowloon Route.
The work involves boring a 2.8km long dual, three-lane road tunnel under central Kowloon between access shafts at Yau Ma Tei and Ma Tau Kok. It also includes 74m of cut-and-cover approach tunnels and a 50m deep central ventilation shaft at Ho Man Tin.
The ‘S’ shaped tunnel will be up to 140m below ground level, pass through seven major fault zones and run beneath four MTR underground railway lines. A variety of excavation methods will be used, ranging from drill-and-blast in hard rock to traditional excavation and heavy temporary supports in soft soils.
According to Bouygues: "This project requires meticulous project management to ensure zero interruption to the activities at ground level. When carrying out drill and blast, an advanced double-deck explosive charging technique will be adopted at sensitive areas near MTR tunnels and building piles to minimise disturbance to the surroundings."
Due for completion in 2025, the Central Kowloon Route is a HK$42 billion (£4.5 billion) project to relieve traffic congestion on Kowloon’s existing east−west roads.
It involves building a 4.7km long dual carriageway linking the Kai Tak development area in the east to the West Kowloon reclamation development in the west, with 3.9m of the route in tunnel.
NEC is also being used to procure the connecting roads at the eastern end of tunnel. Contractor Alchmex−Paul Y Joint Venture was awarded a HK$1.97 billion (£210 million) ECC Option C contract in May to build an 0.7km at-grade section of the route, plus a major interchange including bridges, underpasses and slip roads.
HyD Director of Highways Jimmy Chan said the central tunnel contract was the highest-value NEC target contract awarded by the government so far.
"The NEC emphasises mutual trust and co-operation between the contracting parties and has provisions to enhance cost effectiveness and reduce risk," he said.
The previous largest NEC target-cost contract was the HK$2.59 billion (£270 million) ECC Option C awarded by the Civil Engineering Development Department (CEDD) last year for constructing the main bridge of Cross Bay Link, Tseung Kwan O.
The largest NEC contract so far is the HK$12.08 billion (£1.27 billion) ECC Option B (priced contract with bill of quantities) let by CEDD last year for Tung Chung New Town Extension reclamation and advance works.