The effects of a rigid boundary on soil/structure interaction for concrete slabs on grade

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University of New Brunswick


Much of the slab on grade testing presently done is performed using a thin layer o f subgrade over a rigid boundary, such as a concrete floor. When the slab is loaded during testing, some of the load will be supported by the rigid boundary (concrete floor) when a thin subgrade is used. The rigid boundary provides support for the slab by taking some o f the applied load and minimizing the settlement of the subgrade below it. This poses a problem when the results from this data are applied to practical slab on grade applications where there is no rigid boundary below the slab. This report presents data from a test on a steel fibre reinforced concrete (SFRC) slab on a 150 mm subgrade over a rigid boundary. The data from the test are compared to other similarly tested slabs reported in literature and two identical slabs tested at UNB on a 800mm subgrade. From these comparisons, the effect of the lower rigid boundary on the performance of concrete slabs is investigated.