Foundation Design for Frost Heave

Frost heave is the heaving of the ground surface when frost-susceptible soils, in conjunction with high water table or surface water infiltration, freeze. This paper discusses the foundation design strategy for frost-heave forces in areas with substantial frost depths. Only foundations in seasonal frost areas are discussed. Performance of foundations in permafrost and design of pavement and roads are beyond the scope of this paper. As a real case study, the preliminary study and approach that were implemented for the foundation design in a recent project in Fort Saskatchewan, Alberta, Canada are presented. After preliminary studies, the project decided to implement three primary approaches for foundation designs: (i) Installation of compressible void forms underneath pile-supported foundations; (ii) Installation of 200mm rigid Styrofoam insulation to limit the depth of frost penetration, underlain by 300mm of non frost-susceptible granular fill material, with either soil supported or pile foundations below; and (iii) The use of screw piles with a bond breaker on the shaft above frost line.