Impulse Response Evaluation of Drilled Shafts

Abstract

A test section was constructed at the National Geotechnical Experimentation Site at Northwestern University to assess the applicability of nondestructive testing methods to evaluate deep foundations under inaccessible-head conditions. Tests were performed in both the accessible and the inaccessible conditions to evaluate the effects of intervening structure. This paper focuses on the results of impulse response tests performed on the National Geotechnical Experimentation Site drilled shafts before the pile caps were constructed, i.e., in an accessible-head condition. Based on field experimentation and numerical simulations, the use of impulse response tests to identify lengths of accessible-head shafts is limited primarily by the