Static and Cyclic Axial Load Tests on a Fully Instrumented Pile

Abstract

The results of static and cyclic axial pile load tests performed on a fully instrumented steel H-pile driven into a glacial till deposit are presented. Cyclic loads were applied through a hydraulic system interfaced with an automated electronic-electromechanical closed loop servo system to achieve a controlled load intensity to the pile in a specific shape (sinusoidal) at specific frequency (0.1 Hz). The load-deflection, load transfer, and configuration of the pile during pile driving and after each load increment was measured through an instrumentation system that consisted of load cells, deflectometers, strain gages, accelerometers, and inclinometers. Data obtained in this investigation indicated that: 1. Axial deformation of the pile remained essentially constant prior to and after cyclic axial load application. The behavior of the pile was essentially elastic during cyclic load application. 2. Within the scope of testing performed, cyclic vertical load increments do not effect the load carrying capacity or load transfer characteristics of the pile. 3. Load transfer characteristics varied with the magnitude of applied axial load. The ratio of point bearing resistance to the applied load increased with the applied load. However, the rate of increase generally decreases with increasing applied load.