Effects of embedding depth and load eccentricity on lateral response of offshore monopiles in dense sand: a centrifuge study

Two model piles with outer diameter D = 50 mm are loaded laterally at 100g in a large-beam geotechnical centrifuge. The normal strains on both the tensile and compressive sides are measured using fibre Bragg gratings. An incremental method is introduced to define the pivot point. The testing and analytical programme enables the effect of the embedding depth and load eccentricity to be quantified. The key findings are as follows. (a) The piles generate asymmetric tensile and compressive strains during bending, and the tension–compression asymmetry becomes more pronounced at the pile toe and for shorter piles. (b) The piles transition from flexure to rotation as the embedding depth is decreased from 9D to 3D, where the uniqueness of the ground-level rotation and deflection (θ_g–y_g) relationship disappears. (c) The reaction and deflection (P–y) relationship flattens with increasing embedding depth but seems independent of the load eccentricity.