Experimental study on piled ring foundation resting on RDFS cushion overlying soft clay

The piled ring foundations offer an economic foundation system. Piled ring foundation systems can be used under structures like chimneys, OHRS, and towers. In this paper, an experimental study was carried out to understand the behavior of ring footing (with/without RDFS cushion) and piled ring foundation (with/without RDFS cushion) in soft clays. Total 57 model tests were carried out to comprehend the effect of parameters like variation of radii ratio of ring footing, spacing between piles, a diameter of pile, length to diameter ratio, RDFS cushion on the behavior of the piled ring foundations. The outcome of this study helped in understanding the effect of these factors on axial stiffness, load sharing, load improvement factor, and settlement reduction ratio. From the results of the experimental study, it was found that the ultimate load carrying capacity of the ring and piled ring foundation with RDFS cushion was significantly higher than that of ring footing and piled ring foundation without RDFS cushion. It was also observed that the behavior of ring footing with RDFS cushion resembles that of circular footing.