MIL-HDBK-1004/10
9.10.2
a)
Total submerged area of bulkhead:
Area of PZ 27 piling is 2.96 ft per
lineal foot per foot of depth
Area in water = 2.96 x 36 x 1,000 = 106,560 ft
Area in mud (front) = 2.96 x 15 x 1000 = 44,400 ft
Area on shore side =
sheet piling:
2.96 x 56 x 1000 = 165,760 ft
tie backs:
1" diam x 3.14/144 in./ft x 24'
long x 100 = 365 ft
total = 165,760 + 365 = 166,125 ft
b)
Protective current required on front side:
in
water - 106,560 ft x 0.5 mA/ft = 53.28 A
in mud - 44,400 ft x 0.2 mA/ft = 8.88 A
total - 53.28 + 8.88 = 62.16 A
c)
Protective current required on shore side:
166,125 ft x 0.05 mA/ft = 8.3 A
d) Output from Type A420 Type III aluminum alloy anodes is 4.75 A
(refer to Table 24).
Number of anodes required for current output:
N
=
I/i
where
N
=
number of anodes required
I
=
current requirement (A)
i
=
output per anode (A)
N
=
62.16/4.75
N
=
13.08 (say 13)
e)
Minimum weight of anodes required for 15 year life:
W=
YSI
201
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