UFC 4-152-01
28 July 2005
2-8.2.6
Earthquake.
In areas of high seismic activity, carefully consider construction utilizing sheet
pile bulkheads or walls because of the high lateral earth pressures that can
develop on the sheet piling. When a pile-supported platform (with curtain wall) is
used for a wharf structure in conjunction with hydraulic fill, which is susceptible to
liquefaction, consider a rock dike to resist the lateral forces that may be caused
by liquefaction of the fill. The use of an engineered soil filter fabric between the
rock dike and granular fill should also be considered. In areas of extremely high
seismic risk, and where tsunamis and seiches are anticipated, seriously consider
the floating type as it is less likely to be affected by or will suffer only minor
damage from the seismic activity.
2-8.2.7
Water Depths.
Consider open type construction in all depths of water when accommodating
naval vessels, cargo vessels, and tankers. Depth limits for solid-type
construction, utilizing sheet pile bulkheads, are imposed by the magnitude of the
applied surcharge, subsurface conditions, and freeboard of the bulkhead above
the low waterline. Generally, anchored sheet pile bulkheads may be considered
in water depths up to 30 to 35 ft (9.1 to 10.7 m,) where favorable soil conditions
exist. When greater water depths are required at solid type bulkhead structures,
consider the use of relieving platforms, bulkheads consisting of reinforced high-
strength steel sheet piles, or cellular construction.
2-8.2.8
Subsurface Conditions.
Generally, subsurface conditions do not limit the use of open type construction.
For almost all subsurface conditions, with the possible exception of rock close to
the harbor bottom surface, suitable piles or caissons can be designed. Where
rock is close to the surface and pile seating may be difficult and costly, consider
cellular construction. When open type construction must be used in an area
where rock is close to the surface, piles should be socketed and anchored into
the rock. Consider sheet piling, used for bulkheads or retaining walls in
conjunction with platform wharf structures or combination piers, only when
subsurface conditions indicate that suitable anchorage and restraint for the toe of
the sheet piling can be achieved and where select material is available for
2-8.2.9
Fill Loss.
When precast concrete and steel sheet pile bulkheads are used in pier and wharf
construction, take special care to prevent fill leaching through the interlocks,
causing subsidence of retained fill. Install a filter blanket or other method that
could prevent or control fill leaching to reduce subsidence and consequent
paving maintenance.
2-8.2.10
Advance Bases and Remote Areas.
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