Effect of Spacing and Cross-Sectional Shape on Piled Raft System Subjected to Lateral Cyclic Loading

Abstract

Piled raft foundations usually supporting bridge piers, offshore platforms, marine structures and others are required to resist not only static loading, but also lateral cyclic loading that developed from different sources of loadings. An experimental study was carried out to investigate the effects of spacing and cross-sectional shape of pile on the behavior of laterally loaded piled raft models (1×2), (2×1), and (2×2) having a length to diameter ratio (L/D=40) with the spacing to diameter ratio(S/D) of 3, 5, and 7 embedded in layered soil with partially saturated clay soil. The results indicated that the increase in the lateral resistance in the group of square piles compared to a circular pile under pure loading conditions within the group 1 × 2, 2 × 1 and 2 × 2 are about 16%, 20% and 23% respectively. In addition, the results show that the increase in pile spacing lead to decrease lateral displacement under the same periodic load applied. The performance of all models improved using S/D=7 due to reduce the interaction of pile-soil-pile in the group.