For achieving drilled shaft integrity, post-construction testing by cost effective Non-Destructive Testing (NDT) methods are routinely used in the Transportation Industry. The objective of this project is to review the applicability of NDT methods to test drilled shafts for Transmission Lines to provide concrete characterization of drilled shafts defects and develop guidelines for accepting or rejecting anomalous drilled shafts. This report is based on an extensive literature review, including FHWA manuals, survey results from USDOTs, and published papers from the US and Canadian Transmission Line Industries.
Common NDT methods, such as Cross-Hole Sonic Logging (CSL), Low Strain Pile Integrity Testing (PIT), and Gamma Gamma Density Logging (GDL) are evaluated in depth for use in Transmission Lines. The transfer mechanism of various loads applied on the drilled shafts are discussed. Drilled shaft construction methods, possibilities for defect formation, acceptance criteria developed by Baker et al. (1993), and the need of Quality Control (QC) and Quality Assurance (QA) are discussed.
A comprehensive Decision Tree Model is developed to guide engineers and inspectors working in the Transmission Line Industry to make rational decisions in identifying/accepting/rejecting, as well as remedying, if necessary, a defective drilled shaft.
Non-Destructive Testing, Transmission Line Industry, Decision Tree Model, Quality Control, Quality Assurance.