Cyclic Lateral Loading of a Large‐Scale Pile Group

TLDR

Nine closely spaced steel‑pipe piles were cyclically loaded laterally in stiff overconsolidated clay, with water above ground, and instrumented to compare group behavior with isolated piles. The group exhibited highly nonlinear pile‑soil‑pile interaction and a marked reduction in ultimate soil resistance compared to a single pile, persisting from the first cycle through 100 cycles.

Abstract

A large‐scale group of nine steel‐pipe piles in a closely‐spaced arrangement was subjected to two‐way, cyclic, lateral loading with water above the ground surface. The test was conducted in stiff, overconsolidated clay at a site in Houston, Texas. All of the piles in the group were extensively instrumented to allow the results to be compared with those from other piles in the group and from the testing of an isolated, single pile. The results emphasize the highly nonlinear nature of the pile‐soil‐pile interaction. A substantial reduction in ultimate soil resistance was measured in the group piles relative to that of a similarly loaded single pile for both the first cycle and for 100 cycles of load.