Procedures for Prediction of Dynamic Lateral Pile Group Response in Clay from Single Pile Tests
The design of pile foundations for dynamic lateral loads is significant in the design of both offshore and onshore structures subject to vibratory loads and earthquake motion. Sophisticated numerical models are available for predicting the response of these foundations; however, simple and cost-effective methods are needed to confirm the analysis results and improve the understanding of the overall system behavior. A field testing procedure consisting of slow cyclic load tests and plucking tests is suggested and integrated with simplified single-degree-of-freedom and modal analyses of the test results to produce response functions for dynamic design. The technique is particularly attractive because the field tests may be performed quickly and economically on a test pile or piles installed at the site to determine bearing capacity and/or drivability. The proposed test and analyses procedures were applied to a single pile and nine-pile group installed in stiff clay and tested at the University of Houston pile test facility, and the results are compared favorably with more detailed response information published previously. A good approximation of the pile group dynamic behavior was obtained from the simplified single pile response analysis.