Non-destructive Test (NDT) Methods to Evaluate Integrity of Drilled Shafts

Document Info

Title: Non-destructive Test (NDT) Methods to Evaluate Integrity of Drilled Shafts

Document Type: Article

Authored By: Naresh C. Samtani, PhD, PE, BC.GE, F.ASCE

Sponsoring Agency: NCS GeoResources, LLC

Abstract

Construction processes have a significant influence on the quality and performance of a drilled shaft. The interaction of the construction activities and inherently variable geomaterials is such that the configuration and physical properties of an as-constructed drilled shaft can deviate from a cylinder with uniform physical properties assumed during design process. Such deviations are considered anomalies. Given the rigors of the construction processes some level of anomalies in an as-constructed drilled shaft are to be expected. An evaluation of anomalies is needed to ascertain if they will have an adverse effect on the performance of the drilled shaft which, in turn, can affect the performance of the facility it supports. This article provides information on commonly used Non-destructive Test (NDT) methods to evaluate the integrity of drilled shafts. Test methods discussed include Crosshole Sonic Logging (CSL), Gamma Density Logging (GDL), and Thermal Integrity Profiling (TIP). Information is also presented on use of concreting curve to cross check results from NDTs and vice versa. Guidance is provided for selecting the type of integrity tests for quality assurance.