8.
RECOMMENDED DESIGN & LAYOUT
Design Assumptions
8.1 The standards followed in the preparation of this Report, together with the major sources
of information are listed in Appendix 3.
8.2
The principle factors for which the quay structures have been designed are shown in Table 3.
Function
TABLE 3: QUAY-STRUCTURE LOADINGS
Factors
Velocity of approach≈ ft./sec. normal to quay.
Bollard pull=100 tons.
Berthing
Ship displacement=54,000 tons.
Mooring
Container stacking
Crane supports
i
(a) 20-ft. 20-ton containers and 40-ft.
30-ton containers stacked 2-high, bearing on corner plates only.
(b) 144-ton straddle-carrier wheel loads.
Max. crane lift-50 tons including 1 wt. of spreader, at 110-ft. outreach. Max. typhoon wind speed=160 m.p.h.
Max. working wind speed-40 m.p.h.
Crane weight-500 tons.
Wheel loads @ 5-ft. centres :-
(a) Max, working 45 tons.
(b) Max. typhoon=70 tons.
Quay Alignment
8.3
8.4
Layout
8.5
The practical limits for the alignment of the quaywall between Tsing Chau and Mong Chau have been described in Chapter 5. The alignment now chosen is on the innermost limit and has been arrived at because:-
(a) Considerations of availability of filling material, to be described in Chapter 11, indicate that such material would have to be obtained for the Terminal reclamation at some considerable cost.
(b) Consideration of the nature of the seabed, to be described in Chapter 10, indicates that remedial measures to combat the problem of settlement of the reclamation would be required, also at considerable cost.
(c) With the proposed alignment the amount of land would just be adequate to meet
the requirements of the Terminal.
(d) A quick and familiar form of construction could be used for one berth which could
therefore be brought into use first at the earliest possible time.
(e) Alignment of the fourth berth could be varied to give flexibility.
As noted in paragraph 5.38 the selection of this inner alignment may result in a degree of silting with the consequent need for maintenance dredging, especially at the northern end. However it is considered that this should if necessary be accepted as a recurrent commitment in view of the advantages described in the previous paragraph.
The layout shown on Drawing 16 shows enough land, allowing for the proposed Mass Transport Railway, for two 850-ft. berths and ancillary facilities as a first stage of the Terminal. The widths of working apron and container-marshalling area could be the same as proposed in the 1966 Container Committee Report and shown on Drawing 4, but there would be space for only about 60% of the packing sheds and associated facilities recommended in 1966.
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