MIL-HDBK-1025/5
The filled baskets may be placed vertically on top of each
c)
other.
For greater stability, they should be canted back to about a 4
d)
to 1 batter. Battering may also be done by setback of successive rows for a
terraced appearance.
The gabioned slope shall be backed by a layer of filter cloth
e)
to prevent the pump out of fine material from the earthbank behind it.
Its
Use of gabion construction has been limited so far.
f)
permanence is not yet well established.
Typical Details.
(See Figure 20.)
2.4.4.3
Vertical Bulkhead
2.4.5
Use Criteria.
For small craft berthing basins, consider the
2.4.5.1
following:
Vertical walls reflect waves and should be avoided where surge
a)
and partially attenuated wave penetration into the basin interior cannot be
satisfactorily avoided.
If the site can be readily unwatered and if substrata are not
b)
so fluidic as to require deep cutoff walls, cast-in-place concrete bulkhead
construction shall be used.
In other cases, use sheet piling bulkhead.
c)
Because the perimeter wall in a small craft harbor is seldom
d)
used as a breasting dock, the bulkhead is usually carried only to the low
water elevation, and a partially revetted underwater slope shall extend from
the base of the bulkhead wall down to design depth.
The lower edge of the bulkhead wall shall extend not less than
e)
2 ft (.61 m) below the design lowest water level. Where wave or other water
action occurs, extend the walls below the lowest design low water level to a
minimum depth of two times the maximum wave height to minimize the possibility
of pump out of fine material from behind the wall.
The top of the bulkhead wall shall be 2 or 3 ft (.61 - .91 m
f)
above maximum high water.
Types used for small-craft basins include:
2.4.5.2
Types.
Tieback pile-type timber bulkhead.
a)
Steel or aluminum sheet pile bulkhead.
b)
Concrete bulkhead.
c)
Concrete structure with revetted slope.
d)
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