MIL-HDBK-1025/5
Horizontal Stresses. For a design wind load of 15 psf (see
b)
para. 2.3.5), stringers based on the foregoing vertical-stress criteria will
normally be adequate for horizontal stresses in 3 ft (.91 m) wide fingers up
to 30 ft (9.1 m) long and 4-ft wide fingers up to 40 ft (12.2 m) long
cantilevered from the rigid main walk or header, provided that generous knees
are installed and attachments to the walk or header are adequate to resist the
design moment. For fingers longer than approximately 40 feet, adequate
cantilever strength is difficult to develop, and end guide piles may be
required. The fingers should be designed for the same wind loading criteria,
considering the end to be pinned and the header connection to be rigid at the
outer end of the knee. Cross bracing shall be provided. The bracing can be
in the form of diagonal or knee bracing, in some or all of a finger below a
plank deck, or it can be solid deck plates of plywood, concrete, or glulam
decking.
Securing Flotation Elements. Some float and deck sections are
c)
built as integral units. When the floats are separate, they shall be attached
or cradled under the deck frame. Connections used are as follows:
1) Foam logs or planks are dowelled, bolted, or strapped to
the framing. Water-resistant epoxy glues are being developed that give
promise of producing a strong reliable bond to the deck frame.
2) Large independent pontoons of concrete, fiberglass shells,
or composite construction normally need only to be cradled; i.e., prevented
from sliding laterally by outer stringers and cross struts. This facilitates
their removal for replacement or maintenance when required. However, in areas
exposed to larger waves, they shall be strapped to their saddles.
3) Strapping. If metal straps are used they should be
stainless steel. Nylon straps are suitable, but must be adequately tightened
initially.
4) Bolting. Bolts shall be of corrosion-resistant material.
Strength of Foam. Bearing boards should have sufficient
5)
bearing surface to prevent crushing of the foam. The foam has a safe
compressive strength (with negligible deflection) of approximately 5 psi.
Being weak in bending, bearing contact areas shall be spaced not more than
2 ft (6.1 m) apart along the deck and shall be continuous along each edge.
Figure 11 represents typical deck framing and float
d)
connections in use.
Vertical Loading and Deck Levels
2.3.4.5
Floating piers and docks for small craft should normally ride
a)
with the deck uniformly at 15 to 20 in. (381 - 508 mm) above the water surface
under dead loading to provide ease of boarding and to assure that the side
stringers are below the gunwales of the smaller craft and below the spray
rails of larger craft. The lower limit is necessary to prevent wave
overtopping of the deck at full design live loading.
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