Installation torque measurements of helical piles in dry sand for offshore foundation systems

Helical piles are commonly used onshore as foundation elements for several structures such as bridges, building and towers. The following research considers the use of helical piles as a novel foundation system for the offshore piled facilities. For the design of offshore structures (e.g. renewable energy or oil and gas platforms), the tension on a footing becomes the critical design condition. Among the advantages of helical piles, the high tension bearing capacity is one of the important ones. To investigate the optimum helix-to shaft ratio, the Blessington sand from Ireland has been used for these laboratory tests. CPT tests were performed to determine the consistency of the density for each filling of the sand box. The results suggest that the optimum pile design has a helix-to-shaft diameter (defined as wing ratio) between 1.5 and 2.0.