Route 8 Highway, Tsing Yi to Sha Tin, Hong Kong

The construction of Route 8 (previously known as Route 9) is a major capital project in Hong Kong involving not only road construction, but associated viaducts, bridges and tunnel construction through difficult terrain. Route 8 is a high-capacity highway linking Lantau Island, Kwai Ching, West Kowloon and the Northeast New Territories.

The North Lantau Highway and Lantau Link, which are part of the route, were opened to traffic in 1997. The two remaining sections, which are both under construction in separate projects, include the section between Tsing Yi and Cheung Sha Wan (started in 2003) and the section linking Cheung Sha Wan and Sha Tin (started in 2002). Once completed the road will integrate the route from Chap Lap Kok Airport to Sha Tin and make the airport much more accessible.

The Tsing Yi to Cheung Sha Wan section is scheduled for completion in June 2008 at an estimated cost of HK$11.2bn. The section from Cheung Sha Wan to Sha Tin was completed by mid-2007 at an estimated cost of HK$6.8bn but the commissioning date for this section of the route has not yet been released by the Hong Kong Department of Highways.

TSING YI TO CHEUNG SHA WAN

The Tsing Yi to Cheung Sha Wan section will consist of 7.6km of dual three-lane highway. The major construction elements of the project include: West Tsing Yi Viaduct; Nam Wan Tunnel; East Tsing Yi Viaduct; Stonecutters Bridge; and Ngong Shuen Chau Viaduct.

In addition there will be access ramps connecting Route 8 with the local road network at CT8 and CT9 and ancillary works, including traffic control and surveillance systems, electrical and mechanical systems, geotechnical and drainage works and environmental mitigation measures such as noise barriers, low noise road surfacing and landscaping. The design and construction consultants for this section are Ove Arup and Partners Hong Kong Limited.

EAST TSING YI VIADUCT

This 1.25km dual three lane viaduct is an important part of the new Route 8 straddling a large section of the city to carry the new road. The 100 column structure was started in December 2004 and is scheduled for completion in 2008 (the columns vary in size from 4.8m × 3m to 5.6m × 5m).

The design of the viaduct was by Ove Arup & Partners and the construction is being carried out by Bouygues Travaux Publics, China Harbour Engineering Company Group and Dragages et Travaux Publics (HK) Ltd (RMD Kwikform Hong Kong supplied the formwork for the structure). The viaduct consists of 1,939 prestressed precast concrete segments and will have a total of 5km of access ramps.

CHEUNG SHA WAN TO SHA TIN

The Cheung Sha Wan to Sha Tin section is a 6km-long, dual three-lane highway. The scope of the construction for this section of the project includes:

• Lai Chi Kok Viaduct: 1.43km, dual three-lane elevated carriageway from Lai Wan Interchange to Butterfly Valley which connects to the other section of Route 8 between Tsing Yi and Cheung Sha Wan
• 0.5km, dual three-lane carriageway within Butterfly Valley
• Eagle's Nest Tunnel: 2.1km, dual three-lane tunnel under the Eagle's Nest mountain
• Toll plaza at the valley of Sha Tin Heights
• Sha Tin Heights Tunnel: 0.9km, dual three-lane tunnel under Sha Tin Heights, close to the Tolo fault
• Sha Tin Heights Tunnel Approach: 0.6km, dual two-lane tunnel approach road in Tai Wai connecting to the proposed Road T3, with slip roads connecting to Che Kung Miu Road
• 6.5km of noise barriers, including 4.8km of vertical barriers ranging from 3m to 7m high, 0.8km of semi-enclosures and 0.9km of full enclosures
• Traffic control and surveillance systems, electrical and mechanical, building, drainage, landscaping and geotechnical work

The design and construction consultant for this section are Maunsell Hyder Joint Venture. Environmental consultants include Cinotech Consultants Ltd and CH2M-IDC Hong Kong Ltd. This section of the project will be open to traffic by September 2007.

ROUTE 8 TRAFFIC CONTROL SYSTEM

The Delcan-Imtech-GEC Services Joint Venture (DIG) was awarded the contract for the design and implementation of traffic control and surveillance systems on the entire Route 8 project. The joint venture consists of GEC Services (Hong Kong) Ltd, Delcan International Corp of Canada and Imtech Projects BV of the Netherlands. The contract is worth an estimated HK$255m.

The contract was started in late 2003 and will be completed by October 2007, covering the entire 13.5km road system. Imtech and GEC Services are responsible for the overall system integration and project management, particularly site installation, testing and commissioning. They are also responsible for sourcing the IT equipment for the project, which includes:

• NTCIP standard LED variable message signs
• Speed enforcement camera system
• Synchronous Digital Hierarchy (SDH) telecommunication system
• Digital CCTV surveillance system
• Integrated tunnel radio re-broadcasting system
• Integrated emergency and PABX telephone system

The final partner of the joint venture, Delcan, was responsible for the design, development and implementation of the central control software of the traffic control and surveillance system.

EAGLE'S NEST TUNNEL

The contract for the construction of the Eagle's Nest Tunnel was awarded to a joint venture between Leighton Contractors (Asia) Limited and Kumagai Gumi Company Ltd. Construction began in October 2003 and the estimated cost of the project was HK$1.84bn.

The tunnel forms an important part of the strategic route between Cheung Sha Wan and Sha Tin and was designed to improve the road capacity between Sha Tin and Kowloon in anticipation of future traffic demands generated by development in the northeast New Territories.

The project comprises two 2.1km, three-lane tunnels from Butterfly Valley to Shatin Valley through Eagle's Nest mountain (granite), and all the associated electrical, mechanical and landscaping works that will be necessary. The project was complete by April 2007. The full scope of the construction project included:

• Twin 2.1km, three-lane tunnels
• 400m ventilation shaft
• North and south tunnel portal buildings
• Ventilation building off Tai Po Road
• Three-storey administration building
• Toll plaza and toll collection facilities (in addition to a footbridge, subway and canopy at the toll plaza)
• 500m tunnel approach road
• Miscellaneous earthworks, road works and landscaping
• Electrical and mechanical (E&M) for both the Eagle's Nest Tunnel and the adjacent, separately constructed, Sha Tin Heights Tunnel

Sandvik Tamrock Corp has supplied five new Tamrock Axera tunnelling jumbos for the Eagle's Nest tunnelling project. The first unit was a Tamrock Axera T08, a two-boom jumbo with basket boom and Tamrock Computer Aided Drilling (TCAD) instrumentation. This unit was used at the ventilation shaft and was delivered in April 2004. The remaining four units are all Tamrock Axera T12DATA – three-boom fully computerised jumbos with basket booms. These units were delivered to the site in summer 2004 and were used in the main tunnel with two units drilling side-by-side for the cross section area of height 11.8m and width 16.3m.

LAI CHI KOK VIADUCT AND SLIP ROADS

The Lai Chi Kok viaduct is an elevated road connecting the Ngong Shuen Chau viaduct and the Eagle's Nest Tunnel. The 69 span structure will carry a 1.43km, dual three-lane carriageway and has four slip roads. Two of the slip roads will connect with Ching Cheung Road near Mei Foo and Castle Reak Road at Butterfly Valley, while the other two will provide access for traffic (over 300,000 vehicles per day) on and off the viaduct at Lai Wan Interchange.

The slip roads will cross over the existing Kowloon-Canton Railway Corporation (KCRC) East Rail tracks, the route of future railway tracks and the Tai Wai Maintenance Centre of the Tai Wai-Ma On Shan railway project in the form of two viaducts.

Ten of the supporting piers to the viaducts and their associated foundations will be located within the boundary of the Tai Wai Maintenance Centre. The construction of these structural elements was managed by KCRC and carried out by Gammon Skanska Limited. The major construction work comprised the substructure construction of 36 bored-piles, seven pile caps and ten piers. The remaining construction work on the Lai Chi Kok viaduct was carried out by NECSO Entrecanales Cubiertas SA for an estimated HK$1.07bn. Work started on the construction in October 2003 and the viaduct was completed in April 2007.

The 1,766 segments of the viaduct, some of them weighing over 100t, were lifted into place using a 175m long moving gantry. The last of the segments of the Lai Chi Kok Viaduct (LCKV) was put into place at the end of 2006 and the focus of the work was redirected to the completion of the carriageway.

ROUTE OF THE VIADUCT

The dual three-lane LCKV, passes through the industrial area of Cheung Sha Wan before crossing over one of Kowloon's primary road routes, Ching Cheung Road. Other significant obstacles include four major roads, existing drainage culverts/nullahs, overhead power cables and Mass Transit Railway tunnels.

DESIGN OF LAI CHI KOK

The designers adopted a precast segmental box girder deck with span lengths ranging from 60m to 80m to balance the need for an economical design and keeping within the site constraints. The general principle was to have the deck supported on single columns, to minimise ground level impacts, but with portal frames used where necessary to span over critical ground constraints.

With the flexibility of using both single and portal column supports, the design then focused on where the foundations could be located in order to offset the competing constraints of structural efficiency, traffic requirements and protection of existing structures. The integral design for both the deck and sub-structure allowed an efficient design for the foundations and sub-structure resulting in a direct reduction in the scale of column dimensions, the number of piles, and pilecap dimensions.

The superstructure of the viaduct uses a continuous deck design resulting in only a small number of movement joints. This combined with the integral design results in joints located at approximately 300m to 350m spacing along the axis of the viaduct. This means that there are only expansion joints and bearings at the two abutments at each end of the viaduct and at three internal movement joint piers for the entire 1.4km length of the viaduct.

The design concept behind this was to both reduce the maintenance activities for the viaduct and to take advantage of the ability of the continuous deck to redistribute the significant potential horizontal loading from wind and earthquakes along the continuous sections of the viaduct.

CONSTRUCTION OF THE VIADUCT

The main structure was built using a combination of segment lifting methods. The piers and cross-heads were built in advance of the gantry erection to allow the 920t gantry to 'walk' from pier to pier to erect segments. This arrangement allowed the gantry to follow the complicated geometry of the LCKV and lift the heavy segments. The segments were then stressed together using both internal and external prestressing.

The segments, generally 2.3 to 2.5m in length, were cast in a yard in mainland China and delivered to site via barge to a loading point near the site and then by low loader to the temporary storage yard at the LCKV site. Delivery of the segment to the rear end of the gantry was along the previously constructed section of deck via a specially designed segment carrier.

SHA TIN HEIGHTS TUNNEL

The Sha Tin Heights Tunnel project involved the construction of 0.9km of road tunnel and a toll plaza, along with connecting roads to Road T3 and slip roads to Che Kung Miu Road. The project had an estimated cost of HK$1.308bn. The excavation of the tunnel was started in December 2003 and the tunnel was completed in April 2007. The project was undertaken by the Civil Engineering and Development Department (CEDD) in Hong Kong. The project included:

• Site formation, drainage, geotechnical and landscape works for the toll plaza (toll plaza completed in 2004)
• 0.9km of three-lane twin-bore tunnel underneath Sha Tin Heights
• Dual, two-lane at-grade carriageway of 0.7km linking the Sha Tin Heights Tunnel and Road T3
• Slip roads connecting to Che Kung Miu Road
• Construction of noise mitigation measures