EFFECTS OF PILE EMBEDMENT LENGTHS ON THE PILE BEHAVIOR UNDER REPEATED HORIZONTAL LOADING

Abstract

 Several marine structures with pile foundations have been proposed over the years, and such structures are subjected to repeated horizontal loads in numerous directions and at various load levels under the effects of waves or winds. Additionally, the behavior of piles subjected to load perpendicular to the pile axis is affected by the pile embedment lengths. This study focused on the ratio E_r, which is the ratio of L and l_m1 (L is the length of embedment of a pile and lm1 is the depth of the first zero point of moment of a long pile), and investigated how the behavior of single piles subjected to repeated horizontal loads changes depending on the E_r. The pile head deflection at the maximum load was getting increased when a pile was repeatedly loaded in one direction. On the other hand, it was getting decreased when a pile was repeatedly loaded in alternating directions. The rate of change of the pile head displacement per number of repeated loading cycles was almost independent of E_r for E_r≧1.0, whereas for E_r<1.0, it changed significantly compared to E_r≧1.0. In addition, focusing on the bending moment distribution, for E_r<1.0, it changed little in both one direction and alternating direction repeated loading experiments, while in the case of E_r≧1.0, it changed with repeated loading.