Rationalizing Climate Change for Design of Structures
on Permafrost:
A Canadian Perspective
Don W. Hayley
EBA Engineering Consultants Ltd., Canada
Bill Horne
EBA Engineering Consultants Ltd., Canada
Abstract
The design engineer is challenged by uncertainty when determining
how a plethora of published trends indicating a warming arctic climate
can affect future permafrost stability. A process was developed
in Canada in 1998 for screening projects in an attempt to rationalize
the effects of climate change. Two case histories from the authors'
files are used to illustrate the screening process. One project
is a government building with complex foundation conditions but
a defined service life. The second example is a site reclamation
project that relies on permafrost for stability. Reclamation requires
confirmation that the risk of thaw can be managed to an acceptable
level over the long term. Climate change trends for structures on
permafrost with a defined service life can reasonably be predicted
from historical climate data and climate normals developed over
a period of years (30 years). Global Climate Models (GCM) can be
a better choice when longer term analyses are required. Both methodologies
have limitations that must be balanced with appropriate risk assessment.
A geothermal analysis that includes appropriate climate trend input,
coupled with a failure modes and effects analysis, can provide a
useful tool for evaluating alternatives where long term environmental
risks must be managed.
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