Optimizing the Arrangement of Strain Gauges in Pile Load Testing

Abstract

Abstract The use of strain gauges in a deep foundation element static load test is a common technique to obtain soil strata mobilized resistance. The typical arrangement is several gauges at each of several discrete depths. The gauges at each depth are averaged, the average is converted to a force, and the forces at various depths are differentiated to compute force dissipation into the soil. A simple error analysis leads to the optimal arrangement of gauges in the element cross section, accounting for uneven distribution of strain across the cross-section plane of the element and the possibility of gauge malfunction. By using a case history as an example, the optimal vertical spacing of gauge levels is discussed.