ABSTRACT
Experience shows that limiting thermal design to a structure’s footprint can lead to perimeter settlement in extreme thaw seasons where embankment slopes and foundations permit high lateral heat gain. Using a three-dimensional model and lateral insulation of foundation embankments, the subgrade cooling system (foundation ventilation, thermosyphons, or mechanical refrigeration) can be sized to prevent undermining or perimeter failure of the foundation.
The area adjacent a structure generally has more thermal variables than the structure proper. Asphalt surfaces, snow cover, drainage problems, heated and non-insulated utilities provide varying heat loads. The constructed conditions vary considerably from the natural or pre-existing state and must be considered in design. The proposed model solves for the support angle or slope, or for the cooling required for a given support slope. The depth of thaw at the lateral extension of the foundation soils and insulation must be outside the cone of support provided by the foundation cooling.
