The effects of anchored piles on the horizontal and uplift resistances in offshore structures

Abstract

To increase the horizontal and uplift resistances of piles in offshore structures, pile reinforcements such as anchored piles, batter piles, and micro piles have been generally applied. In this study, the emphasis was on quantifying the reinforcement effect of an anchored pile on the horizontal and uplift resistances of a submerged breakwater. A framework for determining the seabed soil spring constants (p-y curve and t-z curve) is proposed from an analytical method and numerical analysis. Based on the results, a new hyperbolic load transfer curve is proposed to design anchored piles by considering the reinforcement effect, which considers the reinforcement coefficients of horizontal and uplift loads obtained from the load transfer curves. The proposed load transfer curves are compared against the results from the full modeling analysis and show good agreement. Through comparisons with case studies, it is found that the effects of the shear force, bending moment, and displacement are more significant for anchored piles than for unreinforced piles. Thus, the proposed curves appropriately represent the reinforcement effect of anchored piles in offshore structures.