MIL-HDBK-1025/5
Unit weight of stone, maximum stone sizes economically
g)
available for use as armor units, and size and gradation of available
underlayer (bedding) material.
Degree of permeability permissible.
h)
Breakwater Positioning
2.5.2.3
The alignment shall be approximately normal to the primary
a)
direction of wave approach with the shortest possible longshore length of
structure.
It shall be as close to the shore as possible.
b)
It should not encroach on water area needed for an entrance
c)
and fairway in its lee during normal and peak boat traffic conditions.
It shall be only as long as is required to effect quiet water
d)
for a safe entrance.
Design Factors
2.5.2.4
When a small craft harbor is built entirely offshore rather
a)
than in a basin behind the shoreline, its entire outer perimeter, except for
the entrance, shall generally be a breakwater.
If the breakwater is in shallow water, large waves may break
b)
before reaching it. Waves generally break when the depth of water is about
1.3 times the wave height.
If the breakwater is in deeper water, records of the measured
c)
deepwater waves during the highest wave episode ever recorded are used to
determine the design wave height. For rubble-mound design, the design wave
height is the significant height of the one-tenth-percent-occurrence wave
episode, i.e., will not be exceeded in wave height (for any direction within a
90 degree sector centered on the perpendicular to the breakwater's axis) more
than one-thousandth of the time, or about 9 hours each year.
Breakwaters are seldom built to a height that will not be
d)
overtopped by the design wave.
Breakwater types are as follows:
2.5.2.5
Types.
Shore-connected types are:
a)
1) Rubble-mound construction (see Figure 21).
2) Stone-asphalt construction.
3) Cellular steel sheet pile construction (see Figure 22).
Offshore types are:
b)
1) Rubble-mound structure for open ocean or bay exposure.
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