Performance of concrete sidewalks: field studies

This article examines the different failure modes of concrete sidewalks through an extensive field survey ofsidewalk inventories in major cities in the Canadian Prairies. The major form of sidewalk damage is longitudinal cracks. There was no correlation of either the liquid limit or the plastic limit of the soil beneath the sidewalk with the type of sidewalk damage observed in each city. However, the extent of longitudinal sidewalk damage increases when the sidewalks are founded on soils with high plasticity index. Two failure modes (hogging and sagging) are closely examined through the analysis of observed vertical surface movements to explain the occurrence of longitudinal cracks. It is concluded that the rigid body movements (both uniform vertical movement and tilt) are mainly a consequence of frost penetration beneath thesidewalk. Uniform vertical movement is not very sensitive to moisture changes in the soil underneath the sidewalk. The dominant mode of deformation for sidewalks is hogging. The seasonal temperatures have considerable impact on the interaction of the sidewalk with the underlying soil, but an indirect estimate of the flexural strain or differential movement ratio is not sufficient to determine if they are large enough to exceed the tensile strain of concrete.Cet article examine les diff\uc8rents modes de rupture des trottoirs de b\uc8ton ? l\uedaide d\uedune inspection \uc8tendue sur le terrain des inventaires de trottoirs dans les principales villes des Prairies Canadiennes. La principale forme de dommage des trottoirs est caus\uc8e par les fissures longitudinales. Il n\uedy avait pas de corr\uc8lation entre la limite liquide ou la limite plastique du sol sous les trottoirs et le type de dommage observ\uc8 dans chaque ville. Cependant, l\ued\uc8tendue des dommages longitudinaux des trottoirs augmente s\uedils sont construits sur des sols ayant un indice de plasticit\uc8 \uc8lev\uc8. Deux modes de rupture (cintrage etaffaissement) sont examin\uc8s de pr\ucbs ? l\uedaide de l\uedanalyse de mouvements de surface verticaux observ\uc8s, afin d\uedexpliquer la formation des fissures longitudinales. Il a \uc8t\uc8 conclu que les mouvements de corps rigide (mouvement vertical uniforme ou inclin\uc8) sont essentiellement caus\uc8s par la p\uc8n\uc8tration du gel sous le trottoir. Le mouvement vertical uniforme n\uedest pas sensible aux changements d\uedhumidit\uc8 dans le sol sous le trottoir. Le mode dominant de d\uc8formation des trottoirs est le cintrage. Les temp\uc8ratures saisonni\ucbres ont un impact consid\uc8rable sur l\uedinteraction entre le trottoir et le sol. Cependant, l\uedestimation indirecte de la d\uc8formation en flexion ou du mouvement diff\uc8rentiel n\uedest pas suffisante pour d\uc8terminer s\uedils sontsuffisamment \uc8lev\uc8s pour d\uc8passer la d\uc8formation ultime en tension du b\uc8ton.Peer reviewed: YesNRC publication: Ye