TM 5-850-1
CHAPTER 7
LIVE-LOAD REQUIREMENTS
7-1.
Vertical loads.
The velocity and angle of approach used for design
a. Uniform loads. Uniform live loads of 600 and
should be as follows:
(1) Velocity of approach. For destroyers and
1,000 pounds per square foot respectively should be
small craft, use 1.7 feet per second for normal berthing
used for the design of general berthing piers and
conditions.
For a vessel with 50,000-ton loaded
container wharves.
b. Truck loads. American Association of State
displacement or over, use 0.5 foot per second for
normal berthing conditions, and for other vessels, allow
Highway and Transportation Officials (AASHTO) HS20-
0.8 foot per second.
44 loadings will be used for all piers. (see app A.)
(2) Angle of approach with respect to face of
c. Loads on railroad tracks. American Railway
Engineering Association (AREA) E-72 loadings will be
approach should be 20 degrees, and for larger vessels,
used when the railroad is constructed on the pier. (see
10 degrees.
b. Forces from moored ships. Forces due to winds
d. Crane loads. Concentrated wheel loads due to
and currents on moored ships may be estimated in
crane reactions can be obtained from its manufacture.
accordance with the following: (1) Forces due to winds.
To compensate for infrequency of loading and other
The maximum wind force shall be calculated as follows:
factors, only 75 percent of the wheel load values may be
W= A x C x P (7-2)
used in designing deck components (slabs and beams).
where
When designing substructure components (piles and
W= wind force, pounds
pile caps), 100 percent of wheel load values will be
A= exposed area of the broad side of the ship in a
used. An impact factor of 20 percent should be added
light condition, square feet
to the wheel load concentrations in the normal design of
C= shape factor
deck and stringers and 10 percent where two or more
= 1.3
cranes act together; and 10 percent, in the design of pile
P= wind pressure, pounds per square foot
caps and secondary framing members.
e. Impact. Impact factors should apply only to
= 0.00 256 vs
v= wind velocity, mile per hour
concentrated liveload conditions. Apply impact loadings
When ships are berthed on both sides of a pier, the total
to decks, stringers, girders, and pile caps; but not to
wind force acting on the pier, as a result of wind on the
piling or similar members supporting pile caps or
ships, should be increased by 50 percent to allow for
girders.
wind against the second ship.
(2) Forces due to current. For salt water, the
7-2.
Lateral loads.
current pressure in pounds per square foot equals 15 V',
a. Docking impact. The impact energy may be
where V is the velocity of the current in feet per second.
This pressure will be applied to the area of the ship
calculated according to the following equation:
below the waterline when fully loaded. Since the ship is
E =K WV 2
(7-1)
2g
generally berthed parallel to the current, this force is
seldom a controlling factor.
where
c. Winds on piers and pier sheds. The wind
E= impact energy to be absorbed by the dock,
pressure on piers and pier sheds should be calculated
foot-pounds
for the maximum wind velocity in the area, and the
K= coefficient of restitutions
proper shape factor applied for the type of structure on
= .3 for light pile supported structures
the pier.
= 0.5 for large, heavy pile supported structures
d. Earth pressure.
Earth pressure shall be
= 1.0 for solid fill structures
considered in the design.
W= loaded displacement of vessel, pounds
e. Tidal lag. Allow for pressures resulting from
V= component of velocity approaching vessel
differences between tide levels.
Unbalanced
normal to the face of mooring, feet per second
waterheads
g= 32.2 feet per second per second
7-1
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