Iicep.1976.3367 Design and Construction of Kwai Chung Container Terminal, Hong Kong, Berth 1, 2 and...

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Proc. Instn Ciu. Engrs, Part 1, 1976, 60, Nov., 571-592

7752 Design and construction of Kwai Chung container terminal,

Hong Kong, berths 1, 2 and 3

The Paper gives the background to acomplicated systeln of tendering for the construction of three adjoining container berths leading to an unusual series of contracts involving three.developers and two main contractors. I t outlines briefly the Consulting Engineers' design for the main quay structure and the two alternative designs which were eventually constructed. The problems which arose from extremely tight construction programmes combined with difficult site conditions, site congestion and settlement of reclamation are discussed.

Introduction Hong Kong is situated just within the tropics near the mouth of the Pearl River in southern China. The climate is temperate in winter (November-March) but tropical monsoons in summer create hot humid conditions with high rainfall (1 500-3000 mm/year) and tropical cyclones with hurricane force winds (typhoons) these can occasionally be very severe with mean wind speeds of about 130 km/h with 3 S gusts as high as 260 km/h.

2. The container terminal is sited at the mouth of a former sea inlet near the western limit of Hong Kong Harbour, which by 1970 had been largely reclaimed behind a rock-armoured rubble mound breakwater. The terminal straddles the former breakwater and at present comprises three berths, each 305 m long, with back-up areas of 15, 10 and 13 ha. Two former headlands (Texaco and Lai Chi Kok) lie on either side of the reclaimed inlet; the island of Tsing Yi, recently connected to the mainland by a bridge crossing Rambler Channel, is at its nearest point I km offshore of the terminal (Figs 1 and 2).

3. The tidal range is only about 2.5 m except under surge conditions associated with a typhoon, when the level can rise abnormally by up to about 3 m.

4. The area consists mainly of granite with zones of granodiorite. As is usual in the tropics, weathering of the rock occurs to considerable depths but the

Ordinary meeting, 5.30 p.m., 11 January, 1977. Written discussion closes 31 January, 1977 for publication in Proceedirtgs, Part 1.

Scott Wilson Kirkpatrick & Partners, Hong Kong. t Far East Area Manager, SociitC Franqaise d'Entreprises de Dragages et de Travaux Publics, France.

General Manager, International Operations, Nishimatsu Construction Co. Ltd, Japan.

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L I N D S A Y , O S B O R N , H A M O N A N D K I K K A W A

Fig. l . Hong Kong Harbour

topography is severely altered by erosion. The site is located in a relatively recently inundated valley in which recent marine deposits have accumulated some 10-20 m thickness of silty clayey mud overlying colluvial deposits. In situ weathered granite is located at about 20-30 m below Principal Datum (PD, approximately low low water).

5. The site is within the New Territories which were leased from China under a 99 year lease from 1 July, 1898.

,/

History 6. Hong Kong does not have a port authority as such but some of the

functions of a typical port authority are carried out by the Marine Department and the Port Works Division of the Public Works Department. All commercial wharves and dockyards, with the recent exception of cargo handling basins for lighters, are privately owned and operated.

7. In Hong Kong many projects which would be public works in the UK are carried out as private developments, with the government allocating monopoly rights or stipulating land development terms as well as site usage conditions. 572


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K W A l C H U N G C O N T A I N E R T E R M I N A L B E R T H S , H O N G K O N G

Key m Borrow &rear Scale of metres

m Urban development 0 I000

Fig. 2. Plan of site and borrow areas

8. The Kwai Chung area was selected for a container port in the mid-1960s by a Container Committee appointed by the Government of Hong Kong,lea and an engineering study was made by Port Works Division in 1969.3 It was recognized at that time that the physical conditions at this site were far from ideal from a construction point of view but no other practicable alternative existed.

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9. In May 1970 the government invited tenders for the development and operation of four berths, each one a separate entity and each offered on an alternative basis:

(a) basic civil engineering work, excluding buildings and container handling

(b) all construction, apart from approach dredging and access roads, to be

10. Scott Wilson Kirkpatrick & Partners, Hong Kong, had already been commissioned by certain prospective operators to advise on civil engineering aspects and estimated construction costs in preparation for their bids, which had to be lodged by late June, 1970. The firm was then further commissioned by one potential developer, whose user lines planned to introduce their third generation container vessels in mid 1972, to proceed immediately with detailed design and contract preparation so that, if successful when the berths were allocated in late August 1970, they could let a construction contract with minimum delay.

11. The berths were awarded as follows, on basis (b) in each case:

equipment, to be carried out by the government;

carried out by the operator.

Berth

Berth 2

Berth 3

1 : to Modern Terminals Ltd, a Hong Kong company formed especially for the purpose by Overseas Containers Ltd, Ben Line Containers Ltd, Hapag-Lloyd and other international interests.

: to Kowloon Container Warehouse Co. Ltd, a Hong Kong company formed especially for the purpose by Oyama Shipping Co. Ltd and other Japanese interests.

: to Sea-Land Orient Ltd, a Hong Kong company of the American Sea-Land group.

Berth 4 was not allocated, but provision for its future construction, together with a possible fifth berth with a quay at right angles to the general alignment, was retained (Fig. 2).

Tendering and letting contracts 12. There would obviously have been advantages in the developers com-

bining to construct all three berths using a single main contractor, and tenders were invited from selected contractors on this basis as well as on various permu- tations of berth construction. In the event collaboration was possible only to the extent that the construction of berths 2 and 3 was let to Nishimatsu Con- struction CO Ltd, while the contract for berth I was awarded to Societe Franqaise d'Entreprises de Dragages et de Travaux Publics who carried out the work in conjunction with a local firm, Gammon (Hong Kong) Ltd. The contracts were let in January 1971. The general layout of the berths is shown in Fig. 3.

13. The government's sale conditions allocated borrow areas to each berth and indicated how these were to be formed and finished in terraces for subsequent housing development. The borrow areas for berth 1 were on Lai Chi Kok headland and those for berths 2 and 3 partly on the mainland (principally on Texaco headland) and partly on Tsing Yi. It was a condition of sale that the borrow areas should be fully formed, except for approved modifications. Surplus material from borrow areas could be dumped in selected areas of the uncompleted reclamation behind the berths, while dredged material had to be disposed of near Douglas Rock, some 8 km to the south. The sale conditions also incorporated a technical specification for the quay walls and apron (Appendix 1) and imposed a timetable for various stages of construction and development of each berth. 574


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K W A l C H U N G C O N T A I N E R T E R M I N A L B E R T H S , H O N G KONG

0 SCALE OF METRES ~ M J

Fig. 3. General layout, berths 1, 2 and 3

The principal times relevant to this Paper, related in each case to the base date of late August 1970 were:

Berth 1 Berth 2 Berth 3 Completion of quay wall, apron

and reclamation 36 months 36 months 42 months Completion of borrow areas,

including slope protection and drainage 48 months 48 months 54 months

For its part the government undertook to carry out approach dredging and to provide access roads and certain services to meet this programme.

14. One of the reasons why the operators opted to develop the berths thern- selves was that the government’s time scales were nut compatible with their own world-wide shipping interests.

15. The tender documents for the main construction contracts therefore incorporated programmes accelerated from those indicated in 9: 13 to suit the operators’ planned start of operations. Completion of berths l and 2 was set at 18 months and that of berth 3 at 22 months. The Consulting Engineers were appointed only for quay walls, reclamation, drainage and basic electrical work for berths 2 and 3, but their duties in respect of berth 1 included in addition paving and all buildings. Because there was insufficient time and information to prepare details of later work for inclusion in the main contract for berth 1 , very tight intermediate completion times had to be imposed as follows:

( U ) sufficient reclamation completed within 9 months to enable paving to start;

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(b) sufficient reclamation completed within 10 months to enable drainage, water supply and cable laying and the erection of buildings on the landward half to start;

(c) 120 m of quay wall and 120 m of reclamation behind it completed within 14 months to enable crane erection to start.

Details of the companies involved are given in Appendices 2 and 3. 16. Surveys supplied by the government (supplemented by detailed informa-

tion obtained later) showed that the depth of water was between 7 and 9 m below low water and the thickness of mud on the seabed varied between 10 and 20 m. To limit settlement of the new reclamation, it was decided to remove the mud completely, except in berth 3 where a 3 m thickness was left in areas where greater settlement could be tolerated. Other measures to obtain more even settlement included dumping decomposed rock filling up to a level of about - 3 m PD by bottom opening barges; above about + 2.5 m PD it was end tipped and compacted in layers, and in the intermediate range it was saturated. Tem- porary surcharge of selected areas of reclamation by stockpiles of fill material was also specified.

17. Although the work was to be carried out in a period of rising costs, particularly in Hong Kong that of labour, and it was anticipated that international exchange rates were likely to vary, the conditions of contract did not include a fluctuation clause. The developers, whose financial interests are essentially concerned with shipping, considered that tendering contractors would be in a better position to judge the effects of such changes on the construction indust j . This decision was in line with the general policy of very tight budge- tary control on each element of the project.

18. The contracts were on a remeasurement basis with provision of lump sum items for fixed costs such as mobilizing plant, establishing plant facilities and opening up haul routes. The work quantities could not be computed with accuracy at the time of tender and this arrangement ensured that unit prices of the variable elements reflected more accurately the true marginal costs. The contracts also included plant advances on a sliding scale.

19. The Engineer’s design incorporated post-tensioned diaphragm wall construction in a bentonite slurry trench both for the quay walls (with counterforts) and for supporting the landward crane rail. It would have been constructed through a placed bund of decomposed rock, the surplus material in front of the quay wall being subsequently incorporated in the reclamation. It was, however, realized that individual tenderer’s specialist experience and plant might make alternative designs more economical or financially advantageous and these were permitted, with the usual provisos. The accepted tender for berth 1 incorporated a steel sheet piled tied retaining wall and that for berths 2 and 3 an open structure of tubular steel piles with a suspended reinforced concrete deck (Figs 4 and 5). Both tenders incorporated contractor finance linked to export credit.

20. As Rart of their study, the government had commissioned the Hydraulics Research Station (HRS) to carry out model tests cm the behaviour of vessels moored at the berths under a variety of weather conditions with both retaining wall and open-structure quay construction. The site is to some extent sheltered by high ground but is most exposed to the SW, a direction from which sustained monsoon winds are likely. Standard practice is for vessels to leave their berths when a typhoon is imminent, and the tests showed that while some overtopping 576


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r,

Slightly decomporedlfrerh granite

Scale of metres 20'

Fig. 4. Berth f quay structure

of the quay structures might be caused by typhoon waves and surges this was unlikely to be serious.

21. Modern container loading and unloading operations require that both the sway and surge movements of the moored vessel should be limited to about 2 150 mm. The tests showed that these criteria could be met if wave periods did not exceed about 8.5 S with wave heights of more than 300 mm in the case of a vertical wall or 700 mm in the case of an open structure with a rubble slope; records indicated that these limits were likely to be exceeded on only a few days

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LINDSAY. OSBORN, HAMON AND K IKKAWA

Slightly decornpodfreih granite

Sale of metres 0 20

Fig. 5. Berths 2 and 3 quay structure (berth 2 crane shown)

each year. (Subsequent experience has shown that when these limits are reached wind speeds are in any case likely to be above the operating limit of the quayside cranes.)

22. The initial model tests also covered bollard pulls and fender forces and follow-up tests were commissioned by the operators with various arrangements of mooring lines. Further tests were also commissioned to examine the conditions at the junction of berths 1 and 2, where it was feared that unacceptable uplift forces might be developed by water trapped in the reentrant at the transition between the vertical and open quay structures. It was concluded that 578


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dissipation of energy by the sloping revetment under the open structure, coupled with the disruptive effect on waves of the beams beneath the suspended deck, was such as to make special measures, e.g. the provision of blow-off panels, unnecessary.

Planning 23. Because of the tight construction schedule, great attention was paid to

planning and progress monitoring of both design and construction. The Consulting Engineers carried out overall planning and monitoring using a comprehensive precedence diagram network covering each step, from definition of user requirement, through design, statutory approval, delivery of materials and plant to final on-site construction. Many of the items monitored from Hong Kong took place in France, Germany, Japan, Singapore, USA and the UK.

24. For on-site planning and monitoring the Contractors used cascade diagrams, which combine the simplicity of bar charts with the benefit of logic restraints, supplemented by speed diagrams.

Berth 1 Quay structure design

25. The quay structure for berth 1 is designed as a tied retaining wall consisting of massive steel box piles using two Larssen Vs sheet piles with lateral sections of folded flats with intermediate sheet piles driven between and inter- locked with the box piles (Fig. 6). A tie rod is fixed to each box pile and tied back to an anchor wall of Larssen IV sheet piles.

L I J r m i ' * ~.

TURNBUCKLE

.# - BEVELLED'

PLATE BEARING

SWIVEL PLATE SECTION A&

TWO CHANNELS 3 0 0 ~ ~ Y lrin,mm

TIE ROD 105mmDlA.

ATERAL SECTION

'

Fig. 6. Berth 1 quay structure anchorage

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26. The spacing of the box piles was defined, taking into consideration the

(a) as tie rods could be placed only at the location of the box piles, the spacing had to be such that the largest tie rods available could withstand the forces resulting from the soil pressure and other loads such as pull on the bollards;

(b) the box piles had to be able to carry the combined load of the capping beam, the vertical component of the soil pressure and the crane loads;

(c) the box piles had to carry the bending moments resulting from the soil pressure;

( d ) the solution adopted had to be the most economical.

following factors:

27. These various factors led to a spacing of 1.5 m between the axes of adjacent box piles. However, at the final stage of calculation, the results of site investigation and laboratory testing indicated that the maximum bending moment would b e higher than the box piles, as originally designed, could withstand. Therefore stiffening plates were welded in the portion of the box piles where the bending moment was near its maximum. Full scale factory tests revealed that the box piles could not withstand the buckling effect at the location of the tie rod without being filled with concrete 2 m above and below the level at which the tie rod was fixed.

28. Special measures had to be taken at the following points: (a) at each end of the quay wall where three 1000 kN bollards and a 1000 kN

(b) at the location of each 1000 kN quick-release hook. quick-release hook were located within a distance of 15 m;

These special measures consisted of securing to the capping beam additional tie rods which were anchored to a concrete friction slab.

29. The main assumptions used for the design of the quay wall were as follows:

dredged level in front of the quay wall = - 13.4 m PD level of the finished platform= 4.27 m PD internal angle of friction of the soil = 35" total load/crane leg under normal operations = 3240 kN

standard bollard pull = 500 kN under typhoon conditions = + 5430 kN to - 2240 kN

30. The initial calculation of the quay wall structure was made assuming that it was subject to the active earth pressure resisted by the force developed in the tie rods and a triangular passive pressure at the toe. Such a method gives rather pessimistic results and was therefore used only for the assessment of the spacing of the box piles. The final calculations were made using the elastic beam method; this method took into account the lengthening of the tie rods under tension and the various rigidity factors of the soil. Computer calculations using the IBM KPOU program took account of the flexibility of the capping beam under temporary forces such as bollard pulls and horizontal forces on the crane rail under typhoon conditions. The maximum forces resulting from the catculations were: maximum vertical load on a single pile, 2250 kN; maximum bending moment in a pile, 2210 kN m; maximum tension in a tie rod, 960 kN.

31. The anchor wall for the tie rods is located at a distance of 35 m from the quay wall in order to avoid interference with the soil pressure on the quay wall. 580


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K W A l C H U N G C O N T A I N E R T E R M I N A L B E R T H S , H O N G KONG 32. The following precautions were taken to minimize the effects of corrosion

(a) the concrete capping beam was extended to the lowest low tide level

(6) impressed current cathodic protection was provided for the box piles

(c) tie rods and anchor walling were detailed with sufficient margin to allow

of the quay wall:

(the water seldom drops to within 0.5 m of this level);

and intermediate sheet piles;

for corrosion during the 25 year design life of the structure.

Quay wall construction I 33. The sequence of construction work was as follows:

(a) fabrication of the box piles; (b) dredging to remove completely the seabed mud; (c) backfilling of the dredged areas with soft fill material to about - 3 m PD,

(d ) driving the quay wall box piles and intermediate sheet piles and placing

(e) backfilling over tie rods and removal of the temporary mound; (f) construction of the quay wall capping beam, construction of the land-

ward crane beam supported on in situ concrete piles; (g) installation of services; (h) laying paving including asphalt surfacing.

including a temporary mound to seaward of the quay;

the anchor walls and tie rods;

34. To reduce cost the box pile components were shipped in standard lengths and welded on site. The assembly and welding sequence was as follows. The end butt weld of the Larssen Vs sheet piles was made first. Then the components of a 3 2 m long box pile were assembled. This was done by tack welding on a jig specially designed to ensure that the pile, after being assembled, would be straight. After assembly, the pile was removed from the jig using travelling gantries and placed on a welding bench where the main longitudinal welds were made, using two fully automatic welding units, travelling on the side of the pile. After completion of welding fillets on one side of the pile, the pile was turned to weld the other side. The stiffening plates were then welded on the Larssen Vs piles on another bench. All the welding operations were carried out in a purpose-built covered,workshop on Tsing Yi and the welding quality was radiographically controlled.

35. Before the first pile was driven, theoretical analyses (including in situ pressure meter tests) indicated that the length of the longest piles to achieve the required set would be about 29 m. In fact the piles near'the southern end of the berth were about 40 m long before set was achieved.

36. Prior trial driving and testing under representative conditions had not been possible without unacceptable delay to dredging and filling operations.

37. As the jigs and benches could not be extended to allow the welding of box piles longer than 3 2 m, and as required lengths were only known with some accuracy when the nearby piles had been driven, the standard piles of 3 2 m were extended immediately prior to driving by welding an additional section of the required length.

38. The fabricated piles were transported to site from Tsing Yi by barge, and pitched by a barge-mounted crane into a specially designed travelling frame,

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which cantilevered from previously driven piles. The box piles were driven to set with a Kobe 42 diesel hammer and a BSP 8 t single acting hammer.

39. Two piles were test-loaded to 4500 kN (twice maximum working load) using adjacent piles for reaction.

40. Installation of the tie rods was a marine operation using a special designed pontoon with multiple lowering winches. The tie rods had to be installed, jointed and aligned in about 5 m depth of water which was so murky that divers’ visibility was extremely poor; this was the most difficult and time- consuming part of the quay construction.

41. The top 7.5 m of each box pile were fitted with grout tubes, filled with coarse aggregate and grouted with cement grout. Precast concrete muffs were lowered over each set of box piles.

42. When the temporary mound had been partially removed the tie rods were tensioned to 500 kN, and then dredging continued using a small grab working in shallow layers. Piezometers were used to ensure that this operation was not begun whilst excessive pore pressures remained in the fill.

43. The seaward and landward crane beams were then constructed, the latter supported on 550 mm dia. in situ uncased concrete piles.

44. Finally quay fittings and heavy duty crane rails, weighing 73 kg/m with a ball width of 100 mm, were installed with sufficient tolerance in the base-plates to allow adjustment as the quay adjusted to the pressure of the retained fi l l .

Berths 2 and 3 Quay structure design

45. The quay structure for berths 2 and 3 differs fundamentally from that constructed in berth 1. It is an open deck reinforced concrete structure supported on vertical steel piles with the edge of the reclamation retained by a rock seawall (Fig. 5). One significant feature of the design is that there are no raking piles; horizontal forces are resisted by the horizontal subgrade reaction of the material around the piles.4

46. The quay structure in the two berths, totalling a length of approximately 610 m, is divided into bays approximately 61 m long with .movement joints between each bay. Shear joggles are incorporated in the joint between adjacent bays so that both vertical and horizontal deflexions due to crane loads and berthing forces are spread between bays.

47. The quay structure was analysed on the basis of a grid of flexible beams on flexible supports. Assessment of vertical forces on the piles included the effects of negative friction.

Quay construction 48. The piles, with an outside diameter of 700 mm and a wall thickness of

12 mm, were manufactured in Japan in 15 m lengths and shipped to Hong Kong, where they were welded into the required lengths. The piles were fabricated by the longitudinal seam welding process from steel complying with Japanese Standard STK 41, except in the case of piles in the landward row where high tensile steel to Japanese Standard STK 50 was used for the upper 15 m to withstand the higher bending stresses which are induced in this row of piles.

49. The piles are arranged in each bay in ten bents of six piles each with an additional pile in the seaward and landward rows between each bent. All 780 582


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' K W A l C H U N G C O N T A I N E R T E R M I N A L B E R T H S , H O N G K O N G

piles were driven in 4 months by a single pile-driving barge equipped with a Mitsubishi diesel hammer. The piles varied in length from about 35 m near the northern end of berth 2 to about 17 m in the central part of berth 3. The majority of filling under the structure had already been deposited but the self- weight of the piles was sufficient to carry them down through it . The piles required only light driving through the underlying colluvium and in situ decomposed granite until shortly before set was obtained at the point where the toe had reached fresh/slightly weathered rock; set was determined in accordance with the modified Hiley formula.

50. Pile load tests were carried out on three representative piles. The adjacent piles were too widely spaced to be usable as reaction piles and consequently a substantial platform was required to support the necessary kentledge.

51. Near the centre of the quay to berth 3 the profile of fresh rock is sig- nificantly higher than elsewhere and consequently the piles did not have sufficient embedded length. They were keyed to rock by cleaning out the inside of the pile using a shell grab and drilling a 500 mm dia. hole 1.5 m into slightly weathered/ fresh rock, inserting a cage of reinforcement, and then concreting through a tremie pipe.

52. The next stage of construction involved trimming the edge uf the under- water filling to a slope of 1 on 2 and depositing, first, crushed rock and then, by stages, increasingly larger graded rip-rap to provide protection to the edge of the reclamation under the quay s t ru~ tu re .~ Three self-propelled hopper barges equipped with 1.5 m3 clamshell grabs were used for the trimming operation. The same barges subsequently deposited the rock fill using clamshells for the finer filter rock and orange-peel rock grabs for the larger rock sizes.

53. Despite heavy steel H beams welded to temporary brackets on the piles to serve as bracing and subsequently as support to the deck beam soffit shutter, appreciable movement of piles occurred during the rock depositing operation. This was closely monitored, and in areas where the movement was significant the rock was removed and the piles carefully pulled back to correct positions. A wide collar was placed around the piles and a load cell included in the cable rigged from the adjacent formed land for applying the rectifying force to ensure that the piles were not overstressed. Careful examination was carried out and no sign of damage could be discovered.

54. The deck is a grid of heavily reinforced in situ concrete beams. The reinforcement differed from British practice and was notable for the extensive use of welding and the almost total absence of hooks. Virtually all reinforcement was in deformed high yield steel providing good bond characteristics and permitting high stresses. Beams were cast in pours of up to 250 m3 at a time, using a concrete pump delivering at approximately 33 m3/h through a 100 mm diameter steel and Neoprene delivery trunking. To accelerate construction the slabs between beams were precast on site and placed by mobile crane; subsequently in situ concrete was placed between slabs to complete the beams and provide continuity.

55. Special strongpoints were incorporated to provide anchorage for the cranes in typhoons. The piles under certain typhoon anchors had to be cleaned out using a shell grab and the reverse cycle drilling machine which had been used previously for keying in was fitted with a smaller drilling bit to drill a 267 mm dia. hole a minimum of 2 3 m into fresh rock. A 50 mm chain was then lowered into the pile and the bottom link was grouted in with an expanding mortar placed

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LINDSAY. O S B O R N . HAMON AND KIKKAWA

I '? ji

Fig. 7. Fendering arrangements

under water. The chain was then lightly tensioned and the entire,pile concreted. 56: The steel piles were painted with a bitumen epoxy before driving and

repair work was carried out down to a level about 1 m above low water after

alloy anodes has been installed. The replaceable anodes have a design life of driving. A sacrificial anode system of cathodic protection using aluminium

ten years, but the highly variable salinity, which is very dependent on the flow in the nearby Pearl River, may result in the service life being somewhat shorter.

This period accords with the lease of the !and for the berths, and is related to the The entire structure has been designed for an ultimate design life of 25 years.

lease of the New Territories from China. The operators also considered that developments in shipping would in any case necessitate extensive reconstruction to meet their changing needs within this period.

57. Seibu H-type 600 X 2500 L rubber fender units are fixed in pairs at I5 m centmalong the quay (Fig. 7). with 500 kN bollards at each fender strongpoint and a loo0 kN bollard at each end of each berth. At the south end of berth 3 a mooring dolphin, consisting of a massive reinforced concrete head on eight

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raking steel piles with a 1000 kN bollard, has been constructed 30 m beyond the end of the berth.

58. Standard containers have corner castings which project approximately 10-15 mm below the body and hence apply severe point loads to any structure. As a result the open deck is restricted to loaded containers one high and multi- stacking of containers in the area is not permitted. (The berth operators do not envisage ever requiring to stack containers in the quay area.)

59. The asphalt surfacing to the quay structures was carried out with a Marshall design mix and laid in two courses to a total thickness of 60 mm. No waterproof membrane was used to protect the concrete in view of the limited design life of the structure and the very limited number of times that the structure is likely to be overtopped by salt water.

Dredging 60. Marine mud dredged from the site was hauled to the dumping area in

bottom dump hopper barges. In berth 1 dredging was carried out using a diesel electric bucket dredger which has a normal maximum ladder reach to a depth of 20.5 m. As dredging had to be carried to - 19.5 m PD the final cuts had to be carried out at low tide. Output averaged about 230 OOO m3/month. For berths 2 and 3 diesel electric grab dredgers with capacities of approximately 12 and 14 m3 were brought from Japan. These grab dredgers can achieve high outputs, the overall production averaging about 200 000 m3/month per dredger. The use of grab dredgers for this kind of work does, however, have the dis- advantages of requiring far closer control to dredge to an even level over an area and of causing greater dispersion of the mud, particularly in the upper layers where it is softer.

61. Suction or cutter-suction dredgers were not suitable as a delivery pipe- line to the disposal ground was considered too open to damage in typhoons and the material was not suitable for settling out of suspension in hopper barges.

62. In addition to the 2.3 million m3 of mud dredged from the berths, the Port Works Division’s contractor dredged a further 2.3 million m3 from the approaches to the berths to provide a clear depth of 12 m below low water from the open sea to the quay frontage. This work had to be tied in with the timing of berth construction and required close co-ordination between the various contractors.

Reclamation 63. If the material had been available the obvious way to reclaim the site

would have been by the use of hydraulic fill dredged by suction or cutter-suction dredger. Such material is not available for reclamations in Hong Kong where the remaining deposits of granular material are reserved for building uses.

64. For excavating borrow areas the rugged topography and the variable nature of the weathering demand maximum flexibility of plant usage: consequently the contractors used relatively small Traxcavators to load small dump trucks for handling both soft material and blasted rock. The Traxcavators were supplemented by medium size hydraulic face shovels and rope operated face shovels. Temporary bridges were constructed over busy public roads to avoid delays caused by traffic.

65. When rock was encountered all material which could be excavated

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L I N D S A Y . O S B O R N . H A M O N A N D K I K K A W A

without blasting was first removed. Crawler drills then drilled 75 mm dia. holes in a series of 5-10 m benches. AN-F0 explosive was used, the pattern and charges being varied according to the natural jointing of the rock to produce the sizes required for seawalls and paving sub-base and for crushing into concrete paving aggregate and paving base.

66. In the borrow areas on Tsing Yi the Contractor used a different excavation technique, operating bulldozers to push material into adjacent valleys where it was loaded into 18 t dump trucks by large front end loaders. This method produced high output rates during dry weather but was more vulnerable to wet weather.

67. Excavated materials were loaded over purpose built loading ramps into bottom dump barges which transported the material to the site. The berth 1 Contractor used self-propelled barges each with a capacity of approximately 900 m3 specially constructed with bottom door mechanisms which permit the hopper sides to be vertical to allow easy discharge of the material.

68. The Contractor for berths 2 and 3 used hopper barges with inclined sides which resulted in a tendency to arch, causing less even deposition of the material. The barges were shuttled between Tsing Yi and the site by a pusher tug.

69. The total volume of excavation was about 7.3 million m3 of which about 1.9 million m3 was rock.

Seawalls 70. Seawalls were generally of orthodox design with graded rock mounds

built up above the surrounding seabed on a foundation of selected decomposed rock filling.

71. For berths 2 and 3 the Contractor proposed 'an alternative design in which the layer of crushed rock filter was replaced by a woven nylon filter medium. Site trials indicated that provided that rock was not dropped above water level damage to the filter sheet was minimal. Following the trials the filter sheet finally selected had a weight of 330 g/mZ, a thickness of 0.64 mm, an elongation at rupture when dry of 32%, when wet of 30%, and a coefficient of permeability of 1.19 X 10-2 mm/s.

72. The filter sheet was delivered to site in sheets 5.8 m wide X 45 m long rolled on 1 0 0 mm dia. pipes. The rolls were lowered to the seabed where they were unrolled by divers. Individual sheets overlapped each other by approximately 1 m. The area of filter sheet actually used is approximately 1.3 times the net designated area to be sheeted.

73. To minimize the height of the face during end tipping which tends to lead to displacement of material and segregation, bottom dumping was carried out to as high a level as possible depending on the bottom dump barge design; generally bottom dumping was carried to about -2 m PD. In the tidal range the filling material was saturated by jetting and by tidal flooding to obtain a more even moisture content.

74. Above high water level the filling material was compacted in layers using 10 t vibrating rollers which were extremely effective on the silty sandy materials.

75. I t was appreciated that surcharge would have significant benefits on overall settlement and particularly on localized differential settlement, but it was not known whether this would be effective within the very limited time scale permitted by the tight construction programme. Therefore trials were carried 586


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out by installing settlement plates and piezometers and applying a surcharge in stages over a period of several weeks. These tests showed that it was in the operators’ long-term interest to apply surcharge even for a very limited duration provided this did not delay the operational date of the berth. Surplus rock was used as a surcharge material as this could be handled more easily in the wet season during which this operation was carried out.

76. Difficulty was experienced with one section of seawall where apparent foundation failure occurred. Investigation revealed an accumulation of low shear strength unconsolidated material, apparently fine material which had settled out of suspension. Remedial measures included provision of a counter- weight which also acted as a surcharge to accelerate consolidation of the fine material.

Paving 77. The operators of berth 1 opted to use straddle carriers on the basis that

it gave optimum balance between flexibility and available yard area. The machines have a laden weight of around 80 t and tyre pressures of about 7600 mb. This loading requires a paving with 275 mm of Marshall asphalt on a 450 mm crushed rock base. To use excess rock from the borrow areas to the maximum advantage, the crushed rock base was replaced by a sub-base consisting of two courses of selected quarry run rock compacted in 900 mm layers by a 10 t vibrating roller and a 150 mm (minimum) crushed rock base.

78. Difficulty was experienced in obtaining a consistent method of recording flow in the Marshall test apparatus, which is particularly important in view of the sensitivity of Marshall asphalt to fine adjustments in the mix. 79. Special anchorages have been installed in the paving for securing con-

tainers in typhoons. 80. Transtainer operation was chosen for berth 2 to permit greater use of its

limited yard area. The Transtainers operate on in situ post-tensioned concrete trackways, and stack containers four high.

81. In berth 3 only a temporary surfacing has been provided at present so that by the time settlements have largely taken place a final paving can be constructed to suit the eventual operational requirements.

Services 82. Each berth is equipped with a comprehensive system of services including

major storm water drains, foul water drainage, fresh water supply for ships, sprinkler systems and hose-reel systems in buildings and domestic premises, salt water supply for fire hydrant systems including connexions for fire boats and fire engines and for domestic flushing. Extensive ducts have been laid for telephone cables, control cables and electric cabling. All the services had to be closely co- ordinated to be brought into operation within the very tight construction schedule. -

83. Generally services were detailed to be located in service alleys which concentrated the problem in limited areas, permitting those areas where there were no services to be paved at an early date to allow operators to stockpile empty containers and train their container handling crews in preparation for the arrival of the first operational ships.

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Electrics 84. Power is supplied by the utility company at 11 kV to sub-stations in each

berth where it is transformed to 3.3 kV for container cranes and to low voltage, generally 346 V, for all other purposes including yard lighting, refrigerated container power points and domestic uses.

85. Very high quality lighting is required in the container stacking yards as they are operated on a 24 h basis. It is particularly desirable to have as even an intensity. of illumination as possible but at the same time obstruction from lighting columns could not be tolerated in the yard. A system of high-mast towers with the lights mounted about 35 m above ground level was therefore adopted. The standard of illumination is 20 lux.

86. The towers for berth 1 were fabricated locally in 6 m high units from welded tubular steel and erected by the high-lift cranes which were on site for erecting the quay-side container cranes. Site connexions were carried out using high-strength friction grip bolts.

87. In berths 2 and 3 the towers are approximately 30 m high and comprise Vierendeel trusses which were fabricated in Japan and welded in situ.

Buildings 88. As soon as reclamation work was sufficiently far advanced, separate

contracts were let for various buildings, including offices and container loading and unloading sheds (known as container freight stations).

89. The six storey reinforced concrete office building for berth 1 presented a foundation problem as it was located in what had been the deepest part of the original bay, and piles up to 48 m in length were required. The use of uncased in situ concrete piles was not permitted as the office is in the part of the site landward of the breakwater where mud had not been removed. The presence. of a thick layer of unconsolidated marine mud overlain by heavy surcharge of filling resulted in a high risk of necking in uncased piles. Consideration was given to driving standard uncased piles in heavy duty temporary casing and then inserting a thin walled permanent casing. After considering other alternatives, such as jointing precast concrete piles with epoxy resins (which had not been used previously in Hong Kong), it was decided to use steel H piles which were already available. The piles had to be designed for a significant negative friction from the filling as the mud consolidates.

90. The container freight station sheds on berth 1 are in trussed portal frames with high strength friction grip multi-connexions designed and constructed by Arcon (Singapore) Ltd. As the sheds were also constructed in the area where mud had not been removed, the columns have been detailed to allow differential jacking of individual columns to counteract the effects of possible differential settlement (Fig. 8). The sheds have wind-bracing bays at each end and in the centre and in these locations the jacking arrangements had to incorporate the extension arrangements in the diagonal wind bracing.

91. The sheds are clad with light galvanized steel sheeting and it is recognized that with the peak wind loads which might occur during the limited design life of the buildings localized damage will result but the structural integrity of the sheds will not be jeopardized. One of the sheds is on an area of additional land which is held on a lease permitting operational occupation for only 8 years. Major typhoons occur approximately once every nine years and local experience

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KWAl CHUNG CONTAINER TERMINAL BERTHS. HONG KONG

Fig. 8. Column jacking system

indicates that most damage is caused in such storms by flying debris. It is more realistic to try to avoid such debris being deposited in the vicinity of vulnerablq structum rather than to design all aspects of the building for exceptionally high peak loads.

Construction 92. The peak labour and managerial staff employed on all aspects of the

construction of the terminal was in the region of 1800. Regrettably there were

accidents during the potentially most dangerous operations, such as pile driving three fatalities during the course of construction. although there were no serious

and other marine operations. 93. The first operational ship berthed at berth 1 on 5 September, 1972, barely

19 months from the letting of the construction contract and the start of detailed design and construction. and at berths 2 and 3 in January and April, 1973, respectively. Achievement of these dates for the massive and complex work involved, costing some H K W million (S33 million), reflects the m u l t of the high level of international co-ordination which was achieved by all the parties.

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Acknowledgements 94. The Authors wish to thank Modern Terminals Ltd, Kowloon Container

Warehouse Co. ,Ltd and Sea-Land Orient Ltd for permission to publish this Paper, and the vany departments and individuals in the Government of Hong Kong and elsewhere, without whose close interest and co-operation the tight programme could not have been met.

References 1. CONTAINER COMMIITEE. Report. Government Printer, Hong Kong, December

1966. 2. CONTA~NER COMMITTEE. Seconclre~tancirecotl~t~let~~lutions. Government Printer,

Hong Kong, October 1967. 3. PORT WORKS DIVISION. Engineering report on the proposed container terminal at

Kwai Chong. Public Works Department, Hong Kong. 4. FEAGIN L. B. Lateral pile-loading tests. Proc. A m . Soc. Civ. Engrs, 1935,61, Nov.,

272-278 with discussion by Chang Y. L. et al. 5. BURGESS J . S. and HICKS P. H. Riprap profectiotl for slopes subject to wave attack.

Civil Engineering Research Association Research Report 4. Institution of Civil Engineers, London, May, 1966.

. &''

Appendix 1 The following is an extract from the technical schedule incorporated in the sale conditions for each berth:

(a) The quay wall will be loo0 ft long and will have an apron surface level of plus 14.25 ft Chart Datum* at the quay wall face or as specified by the Director [of Public Works].

(b) The quay wall and working apron will be designed for a minimum uniformly distributed load of 1000 Ib/sq ft. The working apron will be 100 ft wide measured from the quay wall face and will have a cross-fall towards the quay wall face of about 1 ft over its width to assist drainage.

( c ) Incorporated in the quay wall and apron design will be two crane-rail beams and these will be spaced to allow for crane rails giving a gauge of 80 ft and will be capable of taking loadings from a 50 ton twin-lift container crane in operation. The front crane rail will be 6 ft from the quay wall face. Specially strengthened points will be provided where cranes can be secured during typhoons.

( c l ) The quay wall, working apron and crane rails will be so designed as to tie in with those of any neighbouring lot already constructed or proposed and will allow for dredging of the berth alongside to a level of -40 ft Chart Datum or lower.

( e ) The quay wall and fender system will be designed for at least 54000 ton displacement container ships berthing at 6 in./s normal to the quay wall or as specified by the Director [of Public Works].

(f) Bollards capable of taking a pull of at least 100 tons will be sited along the cope at intervals suitable for the type of ship to be used.

* Chart Datum is 0.48 ft (150 mm) below Principal Datum. 590


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KWAl C H U N G C O N T A I N E R T E R M I N A L B E R T H S , H O N G K O N G

Appendix 2. Major contractors and sub-contractors

Berth 1 l Berths 2 and 3

Operation Main Major , I Main Major contractor sub-contractor

Site investigation

Dredging

Borrow areas

Quay structure

Reclamation and

Asphalt

Building piling Main electrics

CFS sheds

seawalls

Office

Lighting towers

Internal electrics

Dragages- Gammon

Dragages- Gammon

Dragages- Gammon

Dragages- Gammon

Dragages- Gammon

Dragages- Gammon

GEC (H K) Dragages-

Arcon Gammon

(Singapore)

James Woo (HK)

Dragages- Gammon

Philips (HK)

Malayan Drillers -

Limmer (HK)

Steel Structures

(HK) -

Chung Wah

-

contractor sub-contractor

Nishimatsu Malayan

Nishimatsu Toa Harbour

Nishimatsu Maruiso Gumi

Nishimatsu Malayan

Nishimatsu Toa Harbour

Nishimatsu Pioneer Asphalt

Nishimatsu Oki-Denki

Drillers

Wai Kee

Drillers

Stage 2 works in berths 2 and 3 administered as a separate project

Contracts designed and administered by Port Works Division, PWD Hong Kong:

Approach roads Approach dredging Malayan Drillers

Kumagai Gumi

Appendix 3 Consulting Engineers Scott Wilson Kirkpatrick & Partners (excluding stage 2 works in berths 2 and 3)

Sub-consultants Preece, Cardew & Rider (main electrics, yard lighting and cathodic protection) S. E. Faber & Son (berth 1 office and dangerous goods stores) J. Roger Preston & Partners (berth 1 building services)

Site Supervision Berth 1

Project, Manager (Dragages-Gammon) S. Bauge Resident Engineers P. Christopher

I. M. Donald C. C. Wright

Berths 2 and 3 Project Manager (Nishimatsu) F. Uchigasaki Chief Resident Engineer L. S. Dodd

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Iicep.1976.3367 Design and Construction of Kwai Chung Container Terminal, Hong Kong, Berth 1, 2 and...

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