MIL-HDBK-1025/5
In computing the perpendicular windloading on a system, obtain
d)
the total area on which the wind acts by multiplying the average craft profile
height by the slip width and that product by the total number of slips, then
adding to the result the above water areas of the finger pier ends exposed to
the wind.
Where slips are provided on both sides of the main walk, the
e)
area calculation shall include the side that berths the set of boats with the
largest average profile height.
Multiply the area by 115 percent to account for the wind force
f)
on the sheltered or leeward boat row.
Figure 15 represents a sample computation for lateral loading
g)
on a typical open-pier system.
Anchorage Systems
2.3.6
Selection Criteria. Floating piers and docks should be anchored
2.3.6.1
against lateral movement likely to be caused by wind, water currents, and
vessel, ice or floating-debris impact. For selection of an anchorage system,
consider depth of water in the small craft basin, extent of water-level
fluctuations, the prevailing current, and the submarine bed material.
Systems
2.3.6.2
Anchor Piles. These are simple and are the most commonly
a)
used. They require firm but penetrable subsurface strata, a bottom depth not
exceeding 30 ft (9.1 m) at highest water level, and relatively moderate
horizontal loading conditions. Where pile anchorage is used, guides shall be
incorporated in the deck structure. Commonly used guides are metal hoops,
rectangular wood collars, and rollers. In well-protected basins, use rollers
only for those piles that are found to be in almost continuous contact with
the guides. Use collars with hardwood blocks at other piles. Metal hoops
shall not be used with bare wood piles since they tend to crush the wood
fibers.
Anchor Lines. Where a boat basin is constructed in deep
b)
water or where large water-level fluctuations occur, floating structures are
usually anchored in place with steel cables or chains. Where the entire
floating system requires movement through considerable distances in and out
with water-level changes, special anchor barges with hand winches are used. A
line-anchorage system usually uses two outer anchor lines extending about 45
degrees from the outer corners of the floating system, and two lines tying the
system back to shore.
River Anchorage. River currents usually stress an anchorage
c)
system more severely than still-water or tidal basins. Long, trailing finger
piers can be tied to piles or to dolphins. Figure 16 represents a typical
river anchorage system.
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