Field Apparatus for Measurement of Elastic Rebound and Final Set for Driven Pile Capacity Estimation

Many advances have been made on driven piles bearing capacity tests, such as the static and dynamic load tests. However, the cost and the time necessary to prepare these kinds of tests usually restrict their application to a small percentage of the piles. Consequently, the simple and low-cost ways to estimate the bearing capacity of driven piles, for instance, through the final set and the elastic rebound, can be used to control the majority of the piles, and then the results can be compared with more complex and accurate tests executed in fewer elements. This paper describes the development of an in situ tool to measure the elastic rebound and the final set without any direct contact with the pile. Afterwards, these values can be used to evaluate the bearing capacity based on the dynamic formulas proposed by many authors. The apparatus was tested in three different sites, with the results very close to those obtained with the conventional elastic rebound and the final set measuring method.