Frost heave during winter construction of a building in Ottawa, Canada

Severe temperature conditions at the beginning of the winter caused freezing below shallow footings and floors on grade in an institutional building in Ottawa while it was under construction. Founded on a frost-susceptible soil the building was heaved differentially and damage to floors and partitions resulted. The reinforced concrete frame wracked in the exterior bays by as much as 35 mm vertically, settled back upon thawing approximately to its original position and suffered no serious structural damage. The observations that were made following the discovery that frost heaving had occurred and the measurements taken until all settlement upon thawing had stopped are described.Les temp\ue9ratures tr\ue8s basses survenues au d\ue9but de l'hiver ont provoqu\ue9 le gel en dessous des fondations superficielles et des dalles sur terre-plein d'un b\ue2timent \ue0 usage institutionnel d'Ottawa pendant sa construction. \uc9lev\ue9 sur un sol g\ue9lif, le b\ue2timent a subi un soul\ue8vement diff\ue9rentiel qui a endommag\ue9 les planchers et les cloisons. La structure en b\ue9ton arm\ue9 s'est arqu\ue9e, provoquant un soul\ue8vement vertical de 35 mm au niveau des baies vitr\ue9s, pour reprendre \ue0 peu pr\ue8s sa position originale au d\ue9gel sans grand dommage pour la structure. Les observations qui suivirent la d\ue9couverte du sol\ue8vement d\ufb au gel et les mesures relev\ue9es jusqu'\ue0 la stabilisation au moment du d\ue9gel sont d\ue9crites dans le pr\ue9sent rapport.Peer reviewed: NoNRC publication: Ye