Piled Structure with Sheet-Pile Bulkhead
7.16 Description. A piled concrete structure fronts the reclamation. The reclamation is retained by a sheet-piling wall driven into sand which replaces the soft sea-bed material. The sand is protected by rubble placed on its seaward side.
+14-25'
_M_L.L.W. +2.0"
10.00°c.o.
20" x 20" PRESTRESSED
CONCRETE PILES
CONTAINER-CRANE TRACK SOʻ GAUGE
APPROX EXISTING SEA BED -20.00'
-35.0°
40.0
IN 100
WWW.
COMPACT
SOIL
RECLAMATION FILL
-STEEL SHEET PILING
SAND
OR SELECTED_ DECOMPOSED GRANITE
FILL
SOFT
CLAY
7.16
7.17 Advantages:—
(a) There is some saving in the amount of fill required as the face of the reclamation is
100 ft. back from the quay face.
(b) The construction work would be comparatively quick.
(c) Crane rail settlement virtually eliminated.
7.18 Disadvantages:-
7.19
(a) A large amount of protecting rubble has to be placed carefully between the prestressed
concrete piles to avoid damaging them.
(b) The width of the costly piled structure cannot be reduced as the sand (with rubble protection) has to extend far enough to develop the necessary resistance in front of the sheet piling.
(c) All soft material has to be removed and replaced with sand which involves very deep
dredging in some places.
(d) Crane rail gauge must be decided at the design stage.
Order of Cost. From $14,500 to $17,500 per ft. run of berth depending partly on length of piles required.
7.20 Suitability. Unsuitable because of the high cost and other disadvantages listed.
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