38
Kwai Chung Coastal Road -
(Kowloon
approaches)
Cross-Harbour Tunnel
Island connections and
LIST OF PRINCIPLE CONTRACTS
COMPLETION CONTRACTOR
Paul Y. Construction Co., Ltd.
Ching Hing
Construction Co., Ltd. Fook Lee &
Company
Paul Lee Engineering
PROJECT TITLE
CONTRACT TITLE
VALUE
COMMENCE- MENT DATE
DATE
Lai Chi Kok Bridge
$13.5 x 10°
1-9-66
*31-8-68
Lai Chi Kok Interchange
$ 3.6 x 10°
1-12-68
*31-5-70
Bowrington Canal Extension
$ 2.8 x 10"
14-8-67
*13-3-69
Canal Rd. Flyover
$ 5.0 x 10
12-3-68
11-4-70
Co., Ltd.
Waterfront Road
Canal Road Flyover Extension
$ 5.3 x 10°
24-4-68
27-1-71
Road Connections
Island
$ 4.5 x 10°
15-7-70
14-1-72
Chatham Rd.
$ 3.3 x 10"
Flyover
Mainland
Road Connections
312.2 x 10
24-4-66
14-70
*23-10-69
31-3-72
Connections
-
- mainland
Total completed or in hand
$50.2 x 10°
Cross-Harbour Tunnel
Fig. 1
* Substantial completion certificates issued
tractor's and resident engineer's staff, at which previously agreed working methods were re-appraised and any im- mediate problems were dealt with. Care was taken to avoid conflicting with each contractor's own area of res- ponsibility, and the success of this joint effort has resulted in compara- tively few instances of remedial or condemned work.
Each site had a materials testing laboratory, staffed by the contractor but run by the materials engineer at- tached to the resident engineer's staff. Considerable experience of locally available materials which meet the contract specifications was built up and was made available to contractors whenever possible.
Government laboratories and the Consulting engineers main laboratory were also used so as to avoid the need for specialised testing equipment at each site. Concrete testing was centra- lised at one site, with the advantage of standardising equipment and operating procedures and of allowing direct com-
Fook Lee & Company
Paul Lee Engineering Co. Ltd.
Paul Y. Construction Co., Ltd. Paul Y. Construction Co., Ltd.
parison of the results of testing con- crete produced at different sites. Earthworks and foundations
General excavation
Excavation generally has been straight-forward, with the exception of the Canal Road flyover which had to be constructed around the existing Bowrington Canal. In this case the contractor chose to drive tongued and grooved timber sheeters outside the canal to allow breaking down of the side walls, and subsequently within the canal after breaking out for pine-cap excavation below invert level. De- watering was done using submersible electric pumps in sumps adjacent to each foundation and when excavation was completed, a rock-blanket filter layer was provided draining into the sump, while the pile-cap was construc- ted above. This proved to be only partially successful and it was found necessary to dewater adjacent founda- tions in order to obtain dry working conditions in one of them.
ORGANISATION OF STAFF
Lai Chi Kok Interchange: Chatham Rd: Canal Road
RESIDENT ENGINEER
Mainland Organisation
S.A.R.E. I
L.O.Wa LO.W (I)
Island Organisation
I.O.W (II) 2/A.R.E.”
.5
Engineering Assistant
A.R.E.
Engineering
Assistant
4 supervisors grade II or III
Materials Engineer
SITE LABORATORIES (Staffed by Contractors)
Grade I supervisor 3 grade II or III
supervisor
Supervisor grade I
Supervisor
grade I
L.C.K. Interchange Chatham Rd. Flyover Fig. 2
General Office
Clerk Grade I
Clerk Grade II
Coffer-dams formed by driving shee- ters were completed with internal walings and bracing designed for maxi- mum working room and protected by a surrounding wall of gunny-bags filled with decomposed granite and built up from the existing invert. During non- working periods the pumps were stopped and the foundation allowed to flood to minimise the formation of water channels which would have formed through continual inflow.
Bottom-heave was prevented by driving sheeters to give approximately 3 ft. cut-off below deepest excavation level; in one instance when this depth was not achieved due to obstruction, bottom-heave did occur and the ad- jacent length of side-wall had to be re-built.
Progress on foundation work im- proved considerably when it became possible to lower the water level with. in the canal by constructing temporary dams and using large capacity pumps for general dewatering in addition to the submersible pumps at each work- ing area. This was permitted so as to complete foundation work before the 1969 rainy season. The dams were built in such a way that they could easily be taken down to cater for flood conditions; this had to be done on one occasion and there was no damage to the works other than silting and the dislodgement of some temporary work.
The use of a rock-filler blanket and submersible pumping for soft-ground excavation and subsequent construc- tion below ground water-level was successfully employed for large cul- verts under Kwai Chung Coastal Road and the Bowrington Canal extension.
Trench excavation
The Chatham Road flyover earth- works were simple cut and fill opera- tions but were complicated by plant movement across the busy junction. Special mention should however be made of trench excavation through fill materials to a depth of approximately 25 ft. for a large diameter sewer im- mediately adjacent to a roadway carry. ing very heavy traffic.
The contractor chose to use timber boards in frames approximately 5 ft. deep. The normal local practice of driving over-size struts between wal- ings was not permitted and proper folding wedges were insisted on; this needed a period of 're-education' but there-after the carpenters had little difficulty in meeting the requirements.
Far East BUILDER, January 1971