An Experimental Evaluation of Axial Load Bearing Capacity of Belled and Straight Piles Embedded in Sand

Document Type : Research Note


1 Department of Civil Engineering, SKSVMACET Lakshmeshwar, Affiliated to VTU, Belagavi, Karnataka, India

2 Department of Civil Engineering, Global Academy of Engineering College Bangalore, Affiliated to VTU, Belagavi, Karnataka, India


This paper presents the laboratory axial load test results of two different geometries of model aluminum pile groups, such as equal section piles, and enlarged base (Belled) piles embedded in locally available river sand. For belled piles, the enlarged diameter is achieved by providing a 3-degree outer extension angle at the middle of equal section piles to all three L/D ratios. The load versus settlement tests are carried out on 1X1 and 1X2 of both pile groups having a length to diameter ratios (L/D) of 12, 17, and 22.  The spacing to diameter (S/D) of 3, 4, and 5 times of D and 3, 4, and 5 times of Db.  (Where D is 31mm equal section outer diameter of model pile and Db is 46.7mm enlarged base diameter of belled pile respectively). To avoid overlapping stress zone at bottom of piles during application of load. All the tests are conducted in a brick masonry testing tank of 1X1X1m. The vertical load is applied on a single pile and group of both piles by using a 30kN capacity of hydraulic inverted jack, run by a 1HP single phase motor. The load-bearing capacity is evaluated and a comparison is made between straight piles and belled piles. It is observed that the load-carrying capacity is higher in a belled model pile at a lesser L/D ratio. However, the load-carrying capacity increased 40% higher than straight piles, because of the extension angle. In addition, (S/D) and (S/Db) make significant variations in bearing capacity.


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