19 June 2001
Closed piers, or solid fill piers, are constructed so that water is
prevented from flowing underneath. The solid fill pier is surrounded along the
perimeter by a bulkhead to hold back fill. Figure 2-3 shows a schematic of a solid
fill pier. A special type of solid fill pier is a mole pier. Mole piers are earthen
structures that extend outward from the shore. The sides and offshore end of the
pier are retained and protected by sheet piles, circular cells or walls of either
masonry or concrete. If the water is deep, the pier can be used to berth ships.
Floating piers are constructed of steel or concrete and are connected
to the shore with access ramps. Guide piles in the center of the pier, or a chain
anchorage system, prevent lateral movement and allow the pier to move up and
down with the tide. The floating pier may be a single-deck or a double-deck
structure. A floating pier design concept developed by the Navy is shown in
A more detailed discussion of the design and configuration of piers is
documented in NAVFAC Mil-Hdbk-1025/1N, Piers and Wharves.
Wharves and Quaywalls. Wharves are berthing facilities that are
parallel to the shore. They are normally connected to the shore along their full
length, and a retaining structure is used to contain earth or stone placed behind
the wharf. This retaining structure is often referred to as the quaywall or
bulkhead. Ships are moored along the outshore face of the wharf. The wharf
types are the same as the basic pier types and include open and closed (or solid
fill) configurations. Figure 2-3 shows a solid-fill pier with a configuration similar to
a closed wharf.
Drydocking Facilities. Navy drydocking facilities are used to expose
the underwater portion of ships for repair, modification, inspection, or
maintenance. Several different types of drydocks exist, including graving
drydocks, floating drydocks, marine railways, and vertical ship lifts.
Graving drydocks are fixed basins adjacent to the water's edge and
are constructed of stone masonry, concrete, or sheet pile cells.
They can be closed off from the waterway by a movable watertight
barrier (entrance caisson or flap gate). After closing the barrier, the
basin is pumped dry, which allows the ship to settle on blocking set
on the dock floor. Figure 2-5 shows a schematic of a graving