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Prediction of Dynamic Response of Spread Footings on Sand

Principal Investigator: Dennis R. Hiltunen, University of Florida

Recent decades of research have produced significant advancements in both laboratory and in situ characterization of geotechnical sites, and in numerical methodologies for prediction of dynamic foundation behavior. Thus, two of the key components for calculating the dynamic response of footings have matured substantially. However, there is little recent information available to assess the quality of these new capabilities by way of comparisons between predicted and measured behavior in known conditions and under controlled loading. Further-more, equipment to dynamically load full-scale foundations has not been easily available until the advent of the NEES Equipment Sites. Now, equipment capable of loading full-scale foundations is available, but is as yet untested for performance in a verification application.

The research will be conducted as a NEES pay-load project, and will directly utilize NEES equipment and an existing NEESR project for its conduct. The plan is to instrument, load, and measure the dynamic response of three shallow foundations located on a thoroughly characterized site. In conjunction, class A predictions of dynamic foundation response will be made by a small group of contributors, and the predictions will be compared with measured performance. The results of the prediction event will be presented at a special session during an upcoming Geo-Institute conference, and published in a Geotechnical Special Publication. The prediction event will be part of a campaign to improve dynamic foundation design by bridging the gap between current theory and actual performance. By providing more robustly calibrated design tools, excess design and construction costs created by over conservatism can be reduced.

The model verification afforded by the research provides a realistic opportunity for significant advances in engineering practice as it relates to foundation dynamics. The showcasing of foundation dynamics via the prediction event and a proposed Geo-Institute session and publication provides a multi-faceted opportunity for education and outreach. The event is significantly targeted at practicing engineers, but it is also expected that engineering faculty will work in concert with graduate and undergraduate students to develop predictions of expected foundation response.