Precision of CSLT measurement system for defect detection in bored piles

Abstract

Crosshole Sonic Logging Tomography (CSLT) is an emerging innovative measurement system which provides information on the size, shape, and orientation of defects in a bored pile. In this paper, we quantify measurement precision of the CSTL system by a gage repeatability and reproducibility (R&R) study, in order to understand and model the effects of the test operators, defects, and the test machines on measurement error. We do this by setting up a test pile with three know defects and performing various measurement experiments. We use a feature extraction method to quantify measurement error. Overall, we find that the CSLT has satisfactory repeatability and reproducibility for practical usage of defect detection.

Keywords:

• bored pile
• concrete testing
• crosshole tomography
• CSL
• CSLT
• foundation testing
• Gage R&R
• measurement accuracy and precision
• ultrasonic

Acknolwedgments

We would like to thank Zezhong Wang of City University of Hong Kong for her help with processing the 2D images.

Additional information

Notes on contributors

Tak Cho Eric Ho

Mr. Ho Tak Cho (Eric) is Technical Manager in the Foundation Testing Department of FT Laboratories Ltd. His research focuses on foundation testing and instrumentation monitoring. His email address is [email protected], [email protected]

Inez Maria Zwetsloot

Dr. Zwetsloot Inez Maria is Assistant Professor in the Department of Advanced Design and Systems Engineering. Her research focuses on statistical process monitoring and statistical engineering. Her email address is [email protected].