Ultimate Bearing Capacity of Composite Shell Annular Foundations in Cohesionless Soil

Document Type : Research Article


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


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.


Main Subjects

[1] S. Benmebarek, M. Remadna, N. Benmebarek, L. Belounar, Numerical evaluation of the bearing capacity factor of ring footings, Computers and Geotechnics, 44 (2012) 132-138.
[2] M.L. Ohri, D.G.M. Purhit, M.L. Dubey, Behavior of ring footings on dune sand overlaying dense sand, in: Proceedings of international conference of civil engineers. Tehran, Iran, 1997.
[3] F. Zhu, Centrifuge modelling and numerical analysis of bearing capacity of ring foundations on sand, Memorial University, 1998.
[4] M. Laman, A. Yildiz, Model studies of ring foundations on geogrid-reinforced sand, Geosynthetics International, 10(5) (2003) 142-152.
[5] M. El Sawwaf, A. Nazir, Behavior of eccentrically loaded small-scale ring footings resting on reinforced layered soil, Journal of Geotechnical and Geoenvironmental Engineering, 138(3) (2012) 376-384.
[6] J.H. Boushehrian, N. Hataf, Experimental and numerical investigation of the bearing capacity of model circular and ring footings on reinforced sand, Geotextiles and Geomembranes, 21(4) (2003) 241-256.
[7] A. Karaulov, Experimental and theoretical research on the bearing capacity of ring-foundation beds, Soil Mechanics and Foundation Engineering, 43(2) (2006) 37-40.
[8] J. Kumar, P. Ghosh, Bearing capacity factor N γ for ring footings using the method of characteristics, Canadian geotechnical journal, 42(5) (2005) 1474-1484.
[9]L. Zhao, J. Wang, Vertical bearing capacity for ring footings, Computers and Geotechnics, 35(2) (2008) 292-304.
[10] A. Choobbasti, S. Hesami, A. Najafi, S. Pirzadeh, F. Farrokhzad, A. Zahmatkesh, Numerical evaluation of bearing capacity and settlement of ring footing; case study of Kazeroon cooling towers, International Journal of Research and Reviews in Applied Sciences, 4(2) (2010).
[11] E.S. Hosseininia, Bearing Capacity Factors of Ring Footings, Iranian Journal of Science and Technology, Transactions of Civil Engineering, 40(2) (2016) 121-132.
[12] R.L. Nicholls, M.V. Izadi, Design and testing of cone and hypar footings, Journal of Soil Mechanics & Foundations Div, (1968).
[13] A. Hanna, M.A. El-Rahman, Ultimate bearing capacity of triangular shell strip footings on sand, Journal of Geotechnical Engineering, 116(12) (1990) 1851-1863.
[14] N.P. Kurian, V.M.J. Devaki, Analytical studies on the geotechnical performance of shell foundations, Canadian geotechnical journal, 42(2) (2005) 562-573.
[15] B.B.K. Huat, T.A. Mohammed, Finite element study using FE code (PLAXIS) on the geotechnical behavior of shell footings, Journal of Computer Science, 2(1) (2006) 104-108.
[16] R. Rinaldi, Inverted Shell Foundation Performance In Soil, Concordia University, 2012.
[17] W.R. Azzam, A.M. Nasr, Bearing capacity of shell strip footing on reinforced sand, Journal of advanced research, 6(5) (2015) 727-737.
[18] A. Hanna, M. Abdel-Rahman, Experimental investigation of shell foundations on dry sand, Canadian Geotechnical Journal, 35(5) (1998) 847-857.
[19] D. Esmaili, N. Hataf, Experimental and numerical investigation of ultimate load capacity of shell foundations on reinforced and unreinforced sand, Iranian Journal of Science & Technology, Transaction B, Engineering, 32(B5) (2008) 491-500.
[20] J. Colmenares, S.-R. Kang, Y.-J. Shin, J.-H. Shin, Ultimate bearing capacity of conical shell foundations, Structural Engineering and Mechanics, 52(3) (2014) 507-523.
[21] N.P. Kurian, Shell Foundations: Geometry, Analysis, Design and Construction, Alpha Science International, Limited, 2006.
[23] N. Hataf, M.R. Razavi, Model tests and finite element analysis of bearing capacity of ring footings on loose sand, IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY TRANSACTION B-ENGINEERING, 27(B1) (2003) 0.
[24] H. Rahdar, M. Ghalehnovi, Post-cracking behavior of UHPC on the concrete members reinforced by steel rebar, Computers and Concrete, 18(1) (2016) 139-154.
[25] M. Kazemi, A. Tabaroei, J. Bolouri Bazaz, S. Abrishami, Reconstruction of a Large Scale Sand Specimen in: I.P.C. State Organization for Registration of Deeds and Properties (Ed.), Iran, 2016.
[26] B.M. Das, Principles of foundation engineering, Cengage learning, 2015.
[27] M.T. Adams, J.G. Collin, Large model spread footing load tests on geosynthetic reinforced soil foundations, Journal of Geotechnical and Geoenvironmental Engineering, 123(1) (1997) 66-72.
[28] K. Yamamoto, A.V. Lyamin, A.J. Abbo, S.W. Sloan, M. Hira, Bearing capacity and failure mechanism of different types of foundations on sand, Soils and Foundations, 49(2) (2009) 305-314.
[29] M. Al-Aghbari, Y.-A. Mohamedzein, Improving the performance of circular foundations using structural skirts, Proceedings of the Institution of Civil Engineers-Ground Improvement, 10(3) (2006) 125-132.