Cross-Harbour Tunnel
Bids Soon for Tube Laying
OCAL contractors will be in com-
L petition with groups from the
United
Kingdom. Germany. the Netherlands, the United States and Japan, when lenders are invited in October this year for building Hong Kong's cross-harbour road tunnel.
A four-lane tunnel, it will involve a total expenditure of about HK$211 million. It will be the largest tunnel in the Far East and will be one of the very few in the world to be con- structed by the submerged tube method.
This method involves laying and jointing huge precast tunnel segments in a shallow dredged channel on the sea bed.
Final approval for the project to go ahead is expected to be given on July 7, when the Legislative Council meet to consider a resolution approv- ing the granting of an exclusive fran- chise to the Victoria City Develop- ment Company.
Mr.
Chairman of the company, J.L. Marden, announced recently that work should start in the autumn of
next year. "Every effort will be made." he said, "to speed the work and the tentative opening date is hoped to be January 1, 1970. The project will bring money into the Colony and will provide work during construction for possible
a
persons.
Private Scheme
1.500
"It will be the only tunnel in the world constructed, owned and operat- ed by private enterprise.”
Mr. Marden referred to the forma- tion of a new company, The Cross- Harbour Tunnel Co., Ltd. He said that the function of Victoria City Development Co. had been to carry out the preparatory investigations in- to the feasibility of the project. The stage had now been reached when the scheme could be handed over to the owning and operating company and arrangements were in hand to
transfer the assets and liabilities of Victoria City to The Cross-Harbour Tunnel Co.
"The initial shareholdings in both companies will be identical although of course this will change as the Cross-Harbour Tunnel Co. is expand- ed and new members are admitted... One of the terms negotiated for the possible award of the franchise was that Government should be given the option to take up to 25 per cent. of the equity capital of the company."
Four Lanes
The tunnel will be about one mile long.
Total width of the structure, allowing for ventilation ducts and including wall thicknesses, will be about 100 ft. Internal headroom will be about 16 ft. to enable double-deck buses to be accommodated.
Four lanes of traffic will be carried, Originally, when the Government initiated negotiations to determine the possible terms of a franchise, a scheme for a two-lane tunnel was proposed. The Road Research La- boratory in England were asked by the company to survey traffic condi- tions in the Colony and forecast future needs, and from their report it was concluded that a two-lane tunnel would soon become congested. The four-lane tunnel will be able to carry more than 60,000 vehicles a day.
Tolls will be charged for use of the tunnel and toll gates, probably with administration offices built above, will be located at each end. The charges will be HK$2.50 for cars, $7.50 for lorries and $5 for double- deck buses,
Landfall оп Hong Kong Island will be at a point on the Wanchai waterfront to the west of Kellett Island. The landfall in Kowloon will be on the Hung Hom reclamation to the south of the Hong Kong Techni- cal College.
Government traffic engineers are
now completing plans to cope with the expected increase in motor traffic at both the Hung Hom and Wanchai termini. New major road inter- changes and other supplementary road projects are being planned as part of the general road improvement scheme being undertaken by Govern- ment. Major complexes of flyovers and underpasses are contemplated at both tunnel portals.
a con-
The Victoria City Development Co. will pay HK$12 million as tribution towards meeting the cost of building the road and other engineer- ing works which Government will provide to carry the tunnel traffic.
One the major problems to be settled before work can be put in hand is finding a large area on which to set up the precasting yards for the tunnel segments. The precasting yard for the Ocean Terminal components at Hung Hom is rapidly nearing the end of its work and a site in this vicinity may become available.
This would be most convenient as the yard for the tunnel segments will take the form of a dry dock. The 400 ft. long segments will be cast in a dewatered basin. After construction they will be temporarily sealed, the basin flooded and the sections floated out. They will be towed into position. sunk onto the prepared seabed trench and connected under water.
A section will be sunk by admitting water through a valve. A rubber gasket will be fitted on the end of the segment and temporary bulkeads will be built in close to the ends.
When the segment has been manoeuvred into position, water will be pumped from the compartment between the two bulkheads and the outside water pressure will push the new segment home against the one in position. A permanent seal will then be made with steel plates and grouting.
The tunnel will be protected by a mound of granular material to pre- vent damage by shipping. It will be fully ventilated and fitted with fluorescent lighting.
Consultants
The consulting engineers for the project are the London firms of Scott and Wilson, Kirkpatrick and Part- ners, and Freeman, Fox and Partners.
78
AIR DUCT
Toool
LIGHTING
TRAFFIC SIGNAL S
24-0"
13'
30'
30'
AIR
DUCT
13'
Possible typical cross-section of tunnel
Far East Architect & Builder July, 1965
Page 40Page 41