Building foundations on permafrost: Mackenzie Valley, N.W.T.

• Main Author: Pihlainen, J. A.
• Format: Report
• Language: English
• Published: National Research Council of Canada. Division of Building Research 1951
• Subjects: permafrost; soils; foundations; frost heaving; settlement; pergélisol; sol; fondation ouvrage; foisonnement par le gel; tassement; Basements and foundations; Sous-sol et fondations; Mackenzie River; Mackenzie Valley; Ice; Mackenzie river
• Online Access: https://dx.doi.org/10.4224/20358458; https://nrc-publications.canada.ca/eng/view/object/?id=c5f8a810-8f2f-4de7-b8d6-1d60c2f5003f

Exploratory investigations of the foundations on permafrost at the settlements of the Mackenzie River District were undertaken during the summer of 1950. Timber mudsill foundations were the most common type used, followed by wood, steel, concrete piles, and concrete wall footings. More than half of the foundations studied showed some failure either as a result of frost heaving or settlement. Twenty-five structures were examined in detail giving building type, soil conditions and foundation type. Surface timber mudsill foundations were found unsuitable in frost susceptible soils and showed deterioration in as little as five years. Timber and concrete pad foundations showed similar failures. Recommendations for foundation selection should be preceded by a reconnaisance survey consisting of detailed information on topography, drainage, vegetation, permafrost and housing in the general area. Next, site surveys should be carried out giving details of the soil profile, groundwater level, extent and depth of the permafrost and location and size of ice lenses. Preference should be given to sites with suitable foundation materials such as gravels; to areas free from permafrost or where permafrost occurs permanently; to areas having good drainage; and to areas having non-frost susceptible soils. Lastly a cost and function study should precede the final selection of the foundation type. : Au cours de l'été de 1950, des études exploratoires ont été menées sur les fondations implantées dans le pergélisol lors d'une visite des agglomérations du district du Mackenzie. Les fondations les plus communes étaient les semelles de madriers, suivies du bois, de l'acier, de pieux de béton et de semelles de béton. Plus de la moitié des fondations examinées ont montré des signes de détérioration, soit à la suite de soulèvements dûs au gel, soit à la suite de tassements. Vingt-cinq structures ont été étudiées en dé tail en tenant compte du genre de bâtiment, des conditions du sol et du type de fondation.