Lateral Load Testing of a RC 9 Pile Group

A 3 X 3 bored pile group consisting of nine cast-in-drilled-hole reinforced concrete shafts spaced at 3 pile diameters on center was subjected to reversed cyclic, lateral head loading to investigate group interaction effects across a wide range of lateral displacements. The piles had the same diameter of d = 0.61m and extended approximately 7.6m into the ground.
The test site consists primarily of low plasticity alluvial clay that is expected to exhibit an undrained response to the cyclic lateral loading.
The quasi static loading was applied with a hydraulic control system in displacement-control mode. Extensive Instrumentation consisted of Strain Gauges, LVDTs, Fiber Optic Sensors and Inclinometers. Testing was conducted up to complete structural failure. Excavation of the test specimen provided inside in the failure at the pile/cap hinge region.