TM 5-852-4/AFM 88-19, Chap. 4
U. S. Army Corps of Engineers
Figure 4-86. Load settlement test. single increment37.
ploratory load test.
Two examples of deflection
necessary for the rate of deflection to drop entirely to
measured under single-increment loads are shown in
zero. Normally proof of safe bearing capacity will not be
figure 4-86. The much longer stress adjustment time
a problem because the design load, which includes a
required for the longer pile A, loaded to 120 kips and
factor of safety, will be conservatively low. Application of
embedded in 24 F permafrost, as compared to the
the second increment, increasing the load to 2 times
shorter pile B, loaded to 60 kips and embedded in 30.4F
the design load, is intended primarily to provide a further
permafrost, is readily apparent. If significant continuing
check on the validity of the design load. Deflection
deflection is still occurring 72 hours after application of
measurements normally need not extend beyond 72
the design load increment, observations should be
hours for this second increment, regardless of rate of
continued until a firm conclusion can be drawn as to
continuing deflection. Intermediate increments of load
whether or not the pile will be safe against excessive
between these two may be used if time and other
creep deformation under the design load. It is not
constraints permit.
4-143
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