An approach to characterize cyclic deflection of piles in cohesion less soil media under 1-way and 2-way cyclic loading on sloping ground

Abstract

In general, pile foundations are utilized to support structures like tall buildings, bridges, and transmission towers, which are frequently subjected to lateral stresses initiated by wind, action of waves, earthquakes, or traffic loads. Several high-rise structures, highway and railroad overpasses, as well as transmission towers, are constructed near slopes and rely on pile foundations for support. Due to the effects of wind and waves, pile foundations are continuously subjected to cyclic loads. For piles supporting tall buildings, transmission towers, offshore structures, or infrastructure in seismic zones, 1-way or 2-way cyclic lateral loads are commonly applied. Therefore, while designing pile foundations, it is essential to understand how piles behave laterally when they are located near a sloping crest. One of the primary challenges in ensuring the efficient functioning of the superstructure is analyzing how the soil and foundations respond when exposed to long-term lateral loads, such as wind, over an extended period on the piles of offshore platforms. Because of the presence of slope, the pile’s lateral load capacity decreased due to the reduced ability of the soil to provide passive resistance. This paper presents small-scale 1-g model tests conducted on the sand to assess the loss of pile’s lateral capacity when subjected to 100 cycles under 1 and 2-way cyclic loading. The Relative Density (60%) and varying slopes (Horizontal ground, 1V:3H) with varying spacing (5D and 7D) and aspect ratios (L/D) of 25 and 40 were implemented in this study. Cyclic lateral load tests were performed for sloping as well as horizontal ground. A major reduction in lateral capacity, exceeding 60%, was observed due to the application of cyclic loading. Moreover, the transition from horizontal ground (HG) to sloping ground (SG) decreased the maximum bending moment by 25–40%. This study exemplifies the piles’ behaviour when subjected to cyclic lateral loading while resting on a sloping crest, which represents a critical scenario in pile foundation design.