TM 5-850-1
(2) Pavement. Where cargos are stacked on
consideration initial cost, life expectancy, and cost of
maintenance.
pavements exposed to the sun or where iron-rimmed
(h) available funds.
wood or similar wheeled vehicles run on pavement, use
(2) The principal factors which cause piles to
concrete slabs. Elsewhere, flexible pavements are
deteriorate are:
preferable.
Where concrete pavements are used,
(a) corrosion.
provide expansion joints where the pavement passes
(b) decay.
over the inboard edge of cells or relieving platform.
(3) Railroad and crane tracks. These tracks
(c) insect attack.
(d) marine-borer attack.
may be supported on ties and ballast placed directly on
(e) mechanical wear.
select fills. Where tracks run over relieving platforms,
(f) fire.
loads should be distributed to the platforms as specified
(g) chemical reaction (concrete).
for distribution of wheel loads through fill.
(4) Deck fittings. Connect bollards, bitts, and
In the case of foundation piles buried in the ground, only
cleats to separate foundations embedded in the fills or
the first three factors need to be considered. In the case
tie to bulkhead, platforms, or cell structures.
of piles supporting water-front structures, all of these
(5) Lost fill. Where feasible, provide access
environmental factors must be considered.
c. Fill material. Coarse-grained materials, such as
for replacement of fill losses in solid or combination
structures (some losses through interlocks and other
sand, gravel, and rock, are suitable for fill. Fine-grained
openings are inevitable).
materials such as silt, or cohesive materials such as
f. Other requirements. Provide side curbs, 12 to
clay, are generally not satisfactory because of
15 inches high, for decks. For drainage, decks should
shrinkage, expansion, or settlement and will result in
be crowned or pitched 0.0625 inch per foot, and deck
high maintenance costs and an unsatisfactory base for
drains or scuppers provided. Scuppers should be a
floors. Coarse-grained, cohesionless materials will be
minimum of 2 inches high. Provide minimum 3-inch
compacted to at least 95 percent of modified AASHTO
downpipes for drains and weep holes in all rail slots.
maximum density, and fine-grained cohesive materials
For deck finish, provide float finish (in shed areas, a
to at least 90 percent of modified AASHTO maximum
floor hardener is desirable).
density.
d. Bent spacing. Pier supporting transit sheds
8-3.
Substructure design.
should have substructure pile bents spaced at an integer
fraction of the shed column spacing. Provide a pile cap
be designed for dead loads, plus vertical live loads, plus
located under each column. Bent spacing from 10 to 24
lateral load of mooring or berthing ship, with normal
feet is common for piers without sheds.
e. Other requirements.
allowable stresses; and for dead load, plus half a
As to resistance to
vertical live load, plus seismic load (based on dead load
longitudinal loads, piers wider than 60 feet, and with
plus half a live load), with a one-third increase in normal
expansion joints more than 400 feet apart, do not
allowable stresses of allowable pile capacity.
require batter piles for longitudinal resistance, unless
b. Piling requirements.
The design of pile
designed for multiple berthings. Piers less than 60 feet
foundations depends upon three basic considerations:
wide should be investigated for longitudinal loads due to
first, a consideration of the soil properties and capacities
wind, ice, current, traction, and braking. Batter piles or
usually determined from soil boring tests; second, the
longitudinal braces required for longitudinal resistance
study of pile types and driving equipment using a
may be grouped near the center of pier lengths. As to
dynamic pile-driving formula; and third, the study of pile
scouring, piling (and/or sheet piling) should be
carrying capacities using a static formula. Testpile and
adequately embedded to provide for anticipated
test-load results are usually combined with these studies
scourings.
to achieve best results in pile foundation design.
8-4.
Miscellaneous considerations.
(1) The
following
factors
should
be
a. Expansion joints. Typical expansion joint detail
considered when selecting pile material:
(a) required length of life.
is shown in figure 8-17. Slip joints for all rails, pipes,
(b) character of structure.
and ducts should be provided.
(c) availability of materials.
(1) Size. Expansion joints should provide for
(d) type of loading.
temperature changes of 600 F in moderate climates and
700 F in cold climates.
(f) amount and ease of maintenance.
(2) Shear connectors.
Provide shear
(g) estimated costs of types of piles,
connectors to prevent relative transverse movements of
taking into
pier sec
8-2
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