Title:
Stress Measurement of Reinforcing Bars Embedded in Concrete by Hole-Drilling Method
Author(s):
Mohammad T. Nikoukalam, Shahabeddin Torabian, and Said Bolourchi
Publication:
Symposium Paper
Volume:
364
Issue:
Appears on pages(s):
52-61
Keywords:
concrete; experimental; hole-drilling; in situ; measurement; reinforcing bar; residual; stress
DOI:
10.14359/51745456
Date:
12/1/2024
Abstract:
This research examines the hole-drilling method per ASTM E837, known for its minimal invasiveness, for measuring in situ stress in reinforcing bars embedded within concrete structures. The primary objective is to ascertain the applicability of this method in estimating non-apparent stresses, such as those resulting from the external loads, creep, shrinkage, or alkali-silica reaction, that are needed for structural assessment. Systematic experiments on reinforced concrete beams are conducted to validate the method’s viability in identifying these critical in situ stresses. The findings highlight the potential of the hole-drilling method to enhance structural health monitoring practices, offering an accurate tool for assessing stress states crucial for the maintenance and safety of concrete structures. The results demonstrated that while the hole-drilling method is robust for moderate-stress evaluations (up to about 70% of the nominal yield stress), it overestimates the stress in the reinforcing bar under high-stress conditions near the 100% nominal yield stress. This study contributes to the field by confirming the limits and applicability of the ASTM E837 standard for estimating the existing stress in the embedded reinforcing bars.
Related References:
1. H. Suzuki et al., “Measuring strain and stress distributions along rebar embedded in concrete using time-of-flight neutron diffraction,” Meas Sci Technol, vol. 25, no. 2, p. 025602, 2014.
2. A. Owens, “Application of residual stress techniques in the determination of in‐situ load in reinforcement bars,” Exp Tech, vol. 12, no. 5, pp. 23–27, 1988.
3. A. Owens, “In‐situ stress determination used in structural assessment of concrete structures,” Strain, vol. 29, no. 4, pp. 115–124, 1993.
4. F. A. Kandil, J. Lord, and A. Fry, “A review of residual stress measurement methods--a guide to technical selection,” Middlesex, UK, 2001.
5. G. S. Schajer and P. S. Whitehead, “Hole-drilling method for measuring residual stresses.” Morgan & Claypool Publishers, 2018.
6. G. U. O. Jiang, F. U. Haiyang, P. A. N. Bo, and K. Renke, “Recent progress of residual stress measurement methods: A review,” Chinese Journal of Aeronautics, vol. 34, no. 2, pp. 54–78, 2021.
7. ASTM International, “ASTM E837-20: Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method,” ASTM International, West Conshohocken, PA, 2021.
8. S. S. Birley and A. Owens, “Blind hole drilling technique for residual stress measurement: application in NDT,” NDT International, vol. 13, no. 1, pp. 3–9, 1980.
9. “Surface Preparation for Strain Gage Bonding Instruction Bulletin B-129-8 Surface Preparation for Strain Gage Bonding”, Accessed: May 27, 2024. [Online]. Available: www.micromeasurements.com
10. “Strain Gage Installations with M-Bond 200 Adhesive Instruction Bulletin B-127 Strain Gage Installations with M-Bond 200 Adhesive”, Accessed: May 27, 2024. [Online]. Available: www.micro-measurements.com
11. Vishay Precision Group, “Soldering Techniques for Lead Attachment to Strain Gages with Solder Dots - Tech Tip”, Accessed: May 27, 2024. [Online]. Available: www.micro-measurements.com