Tension Estimation in Anchor Rods Using Multimodal Ultrasonic Guided Waves.

Area of Science:

• Structural Engineering
• Materials Science
• Non-Destructive Testing

Background:

• Post-stressed anchor rods are critical for the safety and serviceability of structures like those at Electricité de France (EDF).
• Current tension estimation methods, such as hydraulic jack measurements, are costly, disruptive, and pose safety risks.
• A reliable, lightweight, on-field method for assessing residual tension has been lacking.

Purpose of the Study:

• To develop and validate a novel, non-destructive method for evaluating the residual tension in post-stressed anchor rods.
• To provide a safer and more efficient alternative to existing tension measurement techniques.
• To enable on-field assessment of anchor rod integrity.

Main Methods:

• Utilized multimodal ultrasonic guided waves for non-destructive evaluation.
• Employed laboratory experiments and simulations to develop the methodology.
• Applied time-frequency analysis to extract dispersion curves for bending, torsional, and longitudinal modes.

Main Results:

• Successfully demonstrated a non-destructive approach to estimate residual tension in anchor rods.
• Enabled the extraction of dispersion curves for the first three wave modes.
• Provided a means to estimate the properties of the steel bar.

Conclusions:

• The developed ultrasonic guided wave method is a promising non-destructive technique for assessing post-stressed anchor rod tension.
• This approach offers significant advantages over traditional methods in terms of cost, operational impact, and safety.
• Future research will focus on field implementation and validation.