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 Surface area of foundation:
A = 52[2(7.5) + 6.25]
= 1,105 ft2
Allowable bearing pressure:
Ws/A = 1,045/1,105
= 0.95T/ft2 < 5T/ft2
The foundation is adequate for the dead and live load
condition.
(3) Determine the average impulse loads on the foundation
slab.
Design charge weight = 1.20 (W)
= 1.20(1,900)
= 2,280 lb.
Using the procedure and data provided in NAVFAC P-397,
the following average impulse loads on the foundation
slab are computed:
_
W1:
ib = 4,400 psi-ms
_
W2:
ib = 4,800 psi-ms
_
W3:
ib = 4,400 psi-ms
(4) Establish the range of critical soil properties to be
utilized in the analyses.
The field description of the soil and the results of the
penetration tests indicate that the soil is a medium
compact gravel; therefore, the structure is analyzed for
the properties of the loose and very compact gravels
provided in Table 32. The properties utilized in the
analyses are presented below:
Loose
Very Compact
Modulus of elasticity (psi)
3,000
20,000
Poisson's Ratio
0.2
0.15
Friction Factor
0.6
0.70
(5) Prepare the input data decks for the computer program.
Since the structure is a cantilever barrier, the "Normal
Option" mode of the computer program is utilized to
analyze the structure.
(6) Run the analysis on the CDC 6600 computer using the
overturning analysis program.
2.08-319
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