Finite Element Based Investigation of Belled Piers in Expansive Soils

Document Type : Original Article


1 Lecturer, School of Civil and Environmental Engineering, Addis Ababa Institute of Technology, Ethiopia

2 Associate Professor, School of Civil and Environmental Engineering, Addis Ababa Institute of Technology, Ethiopia


To address previous limitations of belled piers embedded in expansive soils, a numerical investigation is performed using the finite element-based software Abaqus. A parametric study, cost comparison, and trend line development (for design) were conducted. The parametric investigations indicated that when designing belled piers in expansive soils, increasing the shaft diameter is preferred to increasing the length, or the bell size; the limiting diameter for belled piers is much higher than that for straight shaft piers; most belled piers in expansive soils in Ethiopia do not need tensile reinforcement; and the applied load needed to fully eliminate tensile stresses in belled piers is less than that needed in straight shaft piers. The cost comparison indicated that for smaller values of the swelling pressure and the depth of the swelling zone, straight shaft piers are more cost-effective; while for medium to large values of the swelling pressure and the depth of the swelling zone, large bell size belled piers are more cost-effective. The trend lines indicated that in Ethiopia belled piers with the minimum sizes can be used.


Main Subjects

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