Ultimate Bearing Capacity of Composite Shell Annular Foundations in Cohesionless Soil

Document Type : Research Article

Authors

Civil Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran

Abstract

The foundation shape effects on the stress distribution induced in the soil. Moreover, it has influence on the failure mechanism of the soil. For these reasons, it plays an important role in the ultimate bearing capacity of the foundation. Due to lack of materials, the new design methods attempt to utilize the least amount of material and achieve the maximum efficiency. If shell elements are employed in composite foundations, and the interaction effects are considered, the cost can be reduced. This paper aims to compare the geotechnical performance of the composite annular shell foundation with that of the annular one. For this purpose, the ultimate bearing capacity and the settlement of these foundations are experimentally modeled for various shell angles. The findings prove that the ultimate bearing capacity of the composite foundations is more than that of the annular one. Furthermore, it is observed that increasing the shell angle reduces the ultimate bearing capacity. Moreover, the shell efficiency factor is decreased by increasing the soil relative density. This phenomenon shows that the shells perform more appropriately in low-density soils. Additionally, a novel relation is proposed for predicting the ultimate bearing capacity of the composite shell. It is worth emphasizing that adding the edge beam to composite foundations improves its performance in settlements during failure. Moreover, the efficiency of foundations with edge beams is more than the ones without beam in soils with any density. Hence, using of shells in annular foundation enhances its ultimate bearing capacity.

Keywords

Main Subjects

References

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Amirkabir Journal of Civil Engineering
Volume 50, Issue 4
November and December 2018
Pages 781-792

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