figure 7-27.Extensive concrete encasement of wood pile.
Figure 2-28.Fender pile repair.
extend to a minimum of 3 feet below the top of the
deteriorated wood sheeting. The fill at the inside edge
of the old bulkhead is normally removed before
driving the new sheetpiling. When this is done, a
concrete cap should be placed over the new sheeting
to form a seal with the existing construction.
Maintenance of dolphins includes the replacement
of fastenings and any wire rope wrapping that has
become ineffective through corrosion or wear. If
dolphins are connected by a catwalk, maintenance of
the catwalk includes the replacement of damaged or
deteriorated timbers or the cleaning and painting or the
replacement of the steel members. Repairs of dolphins
include replacement of piles, wire rope wrappings, and
blocking. If any piles have to be replaced, the
fastenings should be removed only as far as necessary
to release the piles that are damaged. Care should be
taken to drive the new piles at the proper angle so they
will not have to be pulled too far to fit them in place.
The size of piles to be replaced should be carefully
noted, particularly at the head or intermediate point
where they are fitted together with the other piles.
Much trouble in cutting and fitting the replacement
piles can be avoided by selecting piles with the proper
size head. All replacement piles should be driven
before any are brought together. After all are driven,
the center cluster should be brought together first and
should be fitted, chocked, bolted, and pinned; they are
then wrapped with wire rope. All cuts in piles for
fittings, bolts, and wrappings should be thoroughly
field-treated with creosote. Frequently, it is more
economical to build a new dolphin, rather than to
repair an existing one.
STONE, MASONRY, AND EARTH
Some structures, such as breakwaters and
seawalls, depend upon their mass for stability against
wave action and currents. Materials commonly used
for such structures are stone, blocks of concrete,
cast-in-place concrete, and earth. Earth structures are
usually converted with a protective coating, such as
riprap, to hold them in place.
The most common cause of deterioration and
damage to mass structures is wave action particularly
during storm conditions. Severe wave action may
move stones out of place when built into a wall or
move others by washing out sections of a breakwater
or causeway. This damage makes the structure more
susceptible to additional damage. Repairs should be
made as soon as possible.
Stone structures are considered to be those
constructed of stone, blocks of concrete, or special
concrete shapes, such as tetrahedrons, piled up or
distributed in a random fashion. Some structures may
have an earth core retained in place by stone,