bolt loads were measured, column tilts obtained,
base level column load can be found in the oppo-
and bearing block supports visually inspected.
site corner, at column A4. The presence of a large
Footing settlements and tilts had been measured
quantity of water at the base of column N1, cover-
ing the footing to a depth of several meters, indi-
in June during previous field work.
From data available from both the June and
cates melting of surface and structural snow and
August work, as well as previous years' work, the
subsequent runoff and collection in the column
following conclusions were drawn:
enclosures. These factors may indicate the cause
of the tilt problem at DYE-2: changing snow con-
High stresses were present in the structure,
ditions at the base of the "warm" side footings due
especially along column A4. These stresses
to the presence of meltwater. Warmer conditions
were approximately the same as those pre-
and the presence of water at the bases of these col-
dicted in the justification for the second mini
umns would cause melting or increased densifi-
life extension.
cation of the snow beneath these footings, which
Extrapolation of the stress data shows an in-
crease in stress beyond a factor of 2.0 (the up-
in turn would undermine the support these col-
per design safe level) before the end of 1988.
umns contribute to the structure. This would con-
Column tilts were continuing at about the
tribute to or even cause the differential settlement
amount predicted earlier (≈ 0.25 cm/m . year).
rates, column and footing tilts, and stress distri-
bution patterns found at DYE-2.
Footing settlements continued to be a prob-
lem. Settlement was linear over the span of
time under consideration and showed no in-
CLOSURE OF DYE-2
dication of slowing. N1 was of special con-
In July of 1988, funds for a second leveling op-
cern due to the amount of water and ice
present in the footing room (≈ 2 m).
eration entailing work similar to that done in 1987
were withdrawn. On 29 July, it was agreed that
Footing tilts continued to increase as expected.
CRREL would "... remeasure stresses in the DYE-2
There had been no significant increase in
frame and re-examine the bearing blocks for further
stress-induced Leuder lines in the bearing block
signs [of buckling failure] as soon as possible ..."
supports on all column footings since June of 1988
(Tobiasson 1988). On 18 August, a CRREL team
(2 months). This was a qualitative assessment and
accompanied by Stewart Osgood of Metcalf &
indicated no further yielding in the supporting
Eddy, Inc., arrived at Sondrestrom Air Force Base.
structure at the column bases over the summer.
On 20 August field work began at DYE-2. Sway
Later examination of photographic data showed
Figure 20. Extrapolation of base level combined stress factors for column A4.
16
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