Experimental studies on the response of single-finned pile under combined vertical-torsional loads in sand

Pile foundations may be exposed to torsional loads caused by horizontal eccentric loads brought on waves, wind and earthquakes, as well as axial load brought on by supporting superstructures. This paper highlights a recent strategy to modify piles known as the finned pile. A series of experimental tests were conducted to increase the torsional capacity of a single pile with/without fins in sand under the influence of vertical loads (V), torsional loads (T) and combined loads (T -> V), these experiments involved altering fins' length, width, shape, and number and knowing the effect of these variables on the piles' maximum torsional capacity. The vertical load-displacement response and the torsion-rotation response have been observed. The results showed that fins improve piles' torsional capacity. It also showed that on piles' maximum vertical capacity for independent vertical or torsional loads is different from that of piles under combined loading. It was found that fins' optimum geometry is that their length equal to 0.6 of the embedded pile's length and their width equal to the pile's diameter, where piles' maximum torsional capacity was (4.12 and 7.36) N.m for regular and finned piles, respectively. Fins increased piles' maximum torsional capacity by about 79%.