Lateral Load Behavior of Pile Group in Sand

A large‐scale group of steel pipe piles and an isolated single pile were subjected to two‐way cyclic lateral loading. The tests were conducted in a submerged firm to dense sand that was placed and compacted around the piles. All of the piles were extensively instrumented so that the variation in soil resistance within the group could be determined. The response of the piles in the group was also compared with the response of the isolated single pile. The loss of efficiency of the piles in the group was related principally to “shadowing” (i.e., the loss of soil resistance of piles in the trailing rows). Piles in the leading row supported a large proportion of the group load and behaved similarly to the isolated single pile. Two‐way cyclic loading had little effect on the distribution of load to the piles in the group, but tended to densify the sand around both the single pile and the group piles.