TM 5-852-4/AFM 88-19, Chap. 4
Pile type: 8-in. pipe, 36 Ib/ft
Soil profile: 0-1 ft peat, 1-20,4 ft (bottom of pile) silt
Pile length: 20.9 ft
Backfill around pile: silt-water slurry
Length below surface: 20.4 ft
Avg temp of frozen soil: 29.2F
Embedment in frozen soil: 16.1 ft'
Test performed: July 1958
Loading schedule: 10-kip increments applied at 24-hr intervals. The deflection shown for an increment is that observed
just prior to application of next increment.
Note: Pile not isolated from soil in thaw zone.
COMPUTATION OF ALLOWABLE DESIGN LOAD
2
Failure load = 147 kipsSurface area of pile in permafrost = 5230 in.
2
Average adfreeze bond stress at failure = 147 kips/5230 in. = 28.1 psi
Adjusting for 10 kips per day rate of loading (by interpolation, Figure 4-85), average adfreeze bond stress at failure = 21.5
psi
Assuming failure stress is 40% greater than average sustainable stress, average sustainable adfreeze strength = 21.5/1.4
= 15.3 psi
Sustainable pile load capacity = 15.3 psi x 5230 in.2 = 80 kips
Using a factor of safety = 2.5, allowable design load = adjusted failure load/FS = 21.5 x 5230/2.5 = 45,000.1b
U. S. Army Corps of Engineers
Figure 4-80. Load test of steel pipe pile.
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