22
actual pile driving the predicted economical pile lengths at the given distances from the Praya along the centre line and edge of the Wharf have proved very accurate and have invariably produced the "set" prescribed, or better, in initial driving.
The pile casting and curing was done on the wharf adjoining the pier, and owing to the limited space which could be made available by the owners the area had to be confined to an absolute minimum and within reach of the 15 ton Lifting Crane at 30'0" Rad. In all, 15 Pallets only could be set up with side forms of 1" thick O.P., tongued and grooved and in Panels 10'0" long. The Pallets are the exact width of the Piles, ie. 18" and are set equally distant from each other, resting on 8 X 4s, longitudinally placed. and 3 X 4s laterally at 2′6′′ centres, that raise them above ground levels. This permits the bottom of the side form- panels to be blocked against the Pallet edges by means of folding wedges against a 3 X 4" Plate between two adjacent Pile-forms. Steel is suspended in the forms from 2 Nos. 3" X 1" straps fixed to pairs of 6" X 3" shoulders 2'-6" apart used also for stiffening mould sides.
A close-up view of the driving rig showing the templates
guiding the piles.
SCHEDULE
TIES TYPE "A'
NO
SIZE LENGTH
TIES TYPE B
No SIZE
END TIES
LENGTH
No SIZE
LENGTH
4′ 7′′
NO OF
FORKS
TOTAL NO.
OF FORKS
WEIGHT
PER PILE
TE
5'-2*
(05
1
46
3036
LENGTH
OF PILE
No OF
PILES
LONGITUDINAL
REINFORCEMENT
89. O LONG
90-0
G6
141
B4-0 LONG
2
64-00
LONG
46
.36
*
52"
100
*
4- 79'-0"LONG
4-Mk 79′-0′′LONG
800"
46
ค
驱
110*
4. 161 74'-0" LONG
F
"
4-7
}
業
44
2024
15 21
I
3′- 3*
Ng
42
1932
14 37
3'-3'
110
B 640 LONG LIG
¿ 35
1-10
I
40
14
3740
1167
1
3'-o'
4-7
60-0
24
8-54-0"LONGI
90
5.10
32
768
107
115.00
Original schedule of the piles required. To the above schedule were later added 34 Nos. 75′0′′ long, 66 Nos. 70'0" long, and 5 Nos. 50′0′′ long, making a total of 397 piles.
Concrete for Piles totals some 66450 cu.ft. and is mixed according to requirements in one or two 10/7s "Benford" tilting drum mixers, diesel driven, and centrally located between the two sections of the Casting Yard. Concrete is placed into forms by shovels from a batcher platform to which it is conveyed over gangways by wheelbarrows. Pile Concrete is a nominal 1: 14: 3 Mix with a 3/4" graded machine crushed aggregate prescribed, Crusher fines being used instead of Sand. The Water Cement Ratio is set at 51.75 lbs. per 110 lbs, Cement with Aggregates in a dry state, and in order to be kept constant the percentage of moisture contained in Aggregates is ascertained daily by "Pycnometer" method and variations made in the volume of water to allow for hydration in accordance with percentages of moisture in aggregates as found on test. Concrete is vibrated in forms by means of electrical internal vibrators, with standby gasoline & air driven internal, i.e. "Shimmy" vibrators at hand at all times in case of Power failure.
The great care taken in the casting of these piles ensure the production of a concrete of a very high density giving a maximum resistance to the action of sea-water.
Two
sets of test cubes are made for each pile cast and at 28 days practically all these cubes test to a crushing strength of 7163 lbs. sq. inch. 3 day and 7 day strengths average 4200 lbs. sq. inch and 6000 lbs. sq. inch. respectively. The highest recorded 28 day Test was 8512 lbs./sq. inch, with the Cube remaining unbroken, the limits of the Green Island Cement Co, testing machine having been reached.
Piles are generally lifted off Pallets and stored on the curing yd, on the third day after pouring and kept continually moist for at least 7 days. Generally Piles are made available for pitching and driving after the seventh day as the limita- tions of space require a quick turnover of Piles. In no case have any defects such as spalling at head and/or cracking developed while pitching Piles into templates or in driving.
Pile Driving. The demolition of the previous Wharf having been accomplished, many months prior to the start of the new Wharf, it was clear that the use of the conven- tional Skid rigs over platforms resting on false Piles would entail considerable expenditure which did not seem warranted by the sole possible advantage of this method, viz, slightly
ni
A general view of the progress of the piling work. The piles in the foreground are ready for
trimming to deck level.
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