Lateral Resistance of Piles Near Vertical MSE Abutment Walls

摘要

Pile foundations for bridges must often resist lateral loads produced byearthquakes and thermal expansion or contraction. In addition, space constraints arealso leading to vertical mechanically stabilized earth (MSE) walls at abutment faces.Available test results indicate that lateral pile resistance can decrease significantly aspiles are placed closer to MSE walls. However, no design procedure is available forassessing the decrease in resistance or the effect of the reinforcement on lateralresistance. In this study, full-scale tests were conducted on two piles spaced at 3.8and 7.3 pile diameters behind a 5.9-m high MSE wall with unusually longreinforcement lengths (≈1.6H). The measured lateral resistance was almost identicalfor both piles suggesting that extra pull-out resistance can compensate for potentialstrength losses produced by proximity to the wall. Measured tensile forces werehigher in the reinforcements adjacent to the pile closest to the wall indicating that thereinforcing grid was supplying additional resistance to pile movement. Backanalysesusing a p-y curve approach in LPILE found the friction angle and k value tobe 39o and 217 MN/m~3, respectively. This k value is 3.6 times higher than that forpiles in sand but comparable to values for gravel from other lateral load tests ingravel.