8. Design of Coastal Structures
261
Often the sheet piles are connected or partially connected sheet piles in
order to construct continuons walls for waterfront structures which includes
a srnall waterfront boat launching facilities to a large dock. Typical crosssection of sheet pile is shown in Fig. 8.19. One of the major advantages of
sheet piles over other retaining structures is that dewatering in the location
is not required compared to other retaining structures.
Several types of sheet piles are commonly used in construction:
(a) wooden sheet piles, (b) precast concrète sheet piles, and (c) steel sheet
piles. Aluminium sheet piles are also marketed. Wooden sheet piles are used
only for temporary, light structures that are above the water table. The
most common types are ordinary wooden planks and Wakefield piles. The
wooden planks are about in cross section and are driven edge to edge.
Wakefield piles are made by nailing three planks together, with the middle
plank offset by 50 mm to 75 mm. Wooden planks can also be milled to
form tongue-and-groove piles. The sélection of steel sheet piles is based on
the section modulus and moment of inertia. Typical sheet pile section and
its corresponding section modulus and moment of inertia is tabulated in
Table 8.1.