April_1966 — Page 72

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PIER HEAD UNLOADING PLATFORM

CATWALK

CATWALK

BREASTING DOLPHIN

HALF FRO

tudinal precast concrete beams for the driveway were designed for two con- ditions:

(a) as simply supported members to

carry the dead-weight of the precast concrete slabs, the in-situ wet concrete topping and other loads during construction.

(b) as continuous beams to carry the live load under permanent condi- tion.

Catwalks

The catwalks, giving access to the dolphins from the pier head unload- ing platform, are constructed of pre- cast concrete slabs bolted on to the precast beams which are supported on pile bents of cast in-situ capping beams on steel piles raked at 1:5.

Fender systems

The principal fender system, for each of the two breasting dolphins. consists of structural steel walings. supported by steel fender piles, which transmit the berthing forces through “Lord" rubber fenders to the dolphin. This system has been used successful- ly by Esso in the past and was consider- ed to be suitable for the present site.

"Lord" rubber fenders consist of solid rubber units which are designed to arch on impact and have good load- and energy-deflection charac- teristics. There is some risk that the outer units might be over-compressed by a corner blow on the fender sys- tem and therefore end-loaded hollow rubber cylinders have been installed to prevent this whilst side-loaded hol-

low square rubber sections take up excessive longitudinal deflections.

The secondary fender systems for the smaller vessels consist of pile- waling systems in conjunction with end-loaded hollow rubber cylinders.

Construction

The works discussed here were car- ried out under two contracts, for both of which Gammon (Hong Kong) Ltd. were the successful tenderers. The pro- gress of both contracts was excellent.

One particularly pleasing aspect of work on site was the good relations that existed between Gammons, the civil engineering contractors and Chi- cago Bridge & Iron (Philippines), the tank and pipework contractors. An important contribution to this har- mony was undoubtedly the fact that tank foundations were ready on or be- fore the programme dates which made it possible for the tank erectors to meet their commitments.

Tank foundations

These went down very well and the graded crushed rock formed a very sound base for the tank erectors to work on. Originally it was specified that the stone base should extend 2ft. beyond the outer face of the tank but this was later increased as it was found that otherwise un- avoidable disturbance and erosion of this base during tank erection tended to extend right up to the edge of the tank and thereby reduce the bearing capacity of the foundation.

Readings were taken of the settle-

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ment of all tanks during water test and arc summarised Fig. 5. Generally settlements did not appear to be (and were not) excessive but in five cases remedial work had to be carried out on the tanks and/or their foundations (Nos. 101-104 and 108).

In these cases the settlement at the centres of the foundations had been considerably greater than those noted around the peripheries of the tanks. Whilst pointing out these problems it must be borne in mind that econo- mics dictated that excavated material from the site should be used as fill and therefore, particularly as time was short, meant that filling had to be carried out generally as previous- ly described.

Although the top surface of the fill was compacted the majority of it (below water) could only be end tip- ped. In general the problems that might arise under these conditions were anticipated and in any case the required water testing of each tank (which is probably up to about 20 per cent. in excess of working load) meant that all excessive settlements were exposed and rectified before the tanks were commissioned.

Piling

Altogether 198 steel piles were driven, most of which were 14 in. x 141⁄2 in. H section, 60 to 70 ft. long. Driving was carried out by means of a double acting compressed-air ham- mer mounted on a frame with pen- dulum leads. The use of this frame made it possible to drive both forward

64

JPB

INTERMEDIATE PLATFORM

PD

T-3PD

SCALE DE FEIN

SIDE ELEVATION OF CENTRAL PIER

Far East Architect & Builder April, 1966