MIL-HDBK-1025/5
Sandwich Deck. It has a polystyrene core glued to a plywood
d)
top and bottom faces and edged with 2-in. (50.8 mm) lumber. It also has high
stiffness and is lightweight. Cost of the sandwich deck compares favorably
with the laminated plank deck.
Separate reinforced concrete deck slabs
Concrete Slab Deck.
e)
are sealed to the lips of open-top
unreinforced floats with epoxy cement.
monolithic part of a float. Concrete decks
Another type of concrete deck is a
nonskid, maintenance-free deck surface.
provide a durable, high-stiffness,
The cost is high in comparison to
timber decking and repairs may be
difficult.
Metal Deck. Sheet metal modular units, with surface anodizing
f)
or baked enamel coatings are used in freshwater environment. Repairs are
difficult if bent or pulled apart at their connections.
Fiberglass and Synthetic Deck. Panels of fiberglass and other
g)
synthetics are used with floating-pier systems. They have little resistance
against torsional bending, and must rely on the framework for stiffness and
prevention of damage by racking action in rough waters. Some types of panels
have excellent wearing qualities, but tend to be rather brittle.
Wearing Surface:
h)
1) The top surface of decking should withstand prolonged
exposure to sunlight, frequent wetting and drying, severe abrasion by scuffing
and dropped objects, and a certain amount of flexure.
2) It should not crack or peel off.
3) It should be nonskid, not prone to staining, and easily
cleaned of oil, paint spills and dirt.
Deck Framing and Float Connections
2.3.4.4
a) Vertical Stresses Induced by Wave Action. Depending on the
weight of the floating system as a whole, and assuming a design wave of
approximately 2 ft (.61 m) high, the section modulus about a horizontal axis
for timber framing: (based on empirical data) should range from a nominal
20 in.3 to 30 in.3 per foot of finger deck-width. Thus an adequate stringer
system for a 4 ft (1.2 m) wide finger floating on foam or lightweight shells
would be a 2 in. by 6 in. (50.8 mm - 152.4 mm) plank inside and a 2 in. by
10 in. plank outside on each side of the finger. However, since all bolt
heads, nuts, and ends of tie rods must be recessed sufficiently into the outer
stringer to avoid damage to boat hulls, a 3 in. or 4 in. (76.2 - 101.6 mm)
nominal thickness is recommended for all outside stringers. The stringers
should be in 16 ft to 20 ft (4.9 - 6.1 m) lengths with butt joint swell offset
and with adequate bolting to develop bending strength. For concrete floats,
the same deck would require stronger framing. In a lightweight system, a
torsion bar of 3 in. or 3-1/2 in. (76.2 mm - 88.9 mm) galvanized pipe with
welded-on end plates, centered under the deck of each finger is recommended.
A glulam beam has been developed which strengthens the side stringer system.
A glulam deck 3-1/4 in. (82.5 mm) thick provides excellent torsional
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