TendonScan360®
The TendonScann360 is a Patent Pending family of Next-Generation External Tendon inspection systems that utilizes Magnetic Flux Leakage (MFL), Programable Semiconductor Hall Sensor, and a 16 Channel detection system. This advance technology detects Loss of Metallic Area (LMA), corrosion pitting, and Local Faults (LF) such as broken wires or cables within external post-tension tendons.
The TendonScan360 system is composed of 3 sensor heads:
TendonScan70 – 76mm / 3.5 inch Sensor Head
TendonScan100 – 115mm / 4,5 inch Sensor Head
TendonScan150 – 152mm / 6.8 inch Sensor Head
The TendonScan360 systems produces a 3 Dimensional graphical display of testing results from each sensor within the sensor array.
Each amplitude signal is color coded for quick recognition of damaged areas along with estimated percentages of Loss of Metallic Areas and Local Faults.
When there is an indication of broken wires/cable or loss of metallic area, the SoftScan software generates a 2 dimensional graphic representation of the tendon and the location of the damage within the tendon in red.
This quickly guides the inspector to the damage areas for further investigation.
Videos of Tendon360® in the Field
Tendonscan360® System Overview
1. TendonScan360 provides a non-destructive evaluation of metallic section loss within external post-tensioning tendons. It consists of two components, an MFL scanner and a Windows-based tablet with proprietary software.
2. The MFL scanner is constructed from lightweight, industrial-grade composite polymers, yielding high-strength, temperature-resistant, and impact-resistant durability features that support an array of strong, permanent rare-earth magnets and an extremely sensitive sensor array.
3. Tendon360’s magnetic homogeneous field induction as well as extended distance detection, enhanced robust sensitivity, and state-of-the-art diagnostic functionality for fine-tuning sensors—along with AI-based standard deviation correction algorithm—enables Tendon360 to detect 0.03 cu in mass loss of one cable. Which is 14% cross sectional area loss or approximately 0.7% loss of metallic area of a 19 strand bundle tendon.
4. The MFL scanner provides 360-degree scanning coverage where adequate space allows. When space is restricted, a 120-degree bottom section can be quickly detached to provide scanning coverage of 240 degrees. This allows scanning of tendons along the flange and web sections of the box girder.
5. The sensor array is composed of programmable, semiconductor-based Hall effect sensors that are highly sensitive to low levels of electromagnetic energy (magnetic flux leakage) and capable of detecting local fault (LF) indications—such as wire or strand breaks—and loss of metallic area (LMA) indications, including corrosion pitting and gradual loss of metallic cross-sectional areas.
6. The MFL scanner assembly, which traverses along the free length of the external post-tensioning (PT) tendon, rides on a set of impact-resistant rubber wheels that maintain a constant distance of 0.25 inches between the face of the magnet/sensor array and the surface of the HDPE duct.
7. When loss of metallic area is detected, the tendon is wrapped with an orange, 2-inch-wide ribbon that includes details of the metallic loss and identifies the exact location for further investigation. This allows a follow-up inspector or other personnel to walk through the box girder and quickly locate defective areas along the tendons.
8. The Tendon360 system will be delivered in a single mid-sized Pelican case to facilitate transport, enable handling within a box girder, and ensure lightweight portability for shipping or air travel.
9. The test data generated by the scanner is wirelessly transmitted to a lightweight, Windows-based tablet, where real-time results are monitored and recorded.
SoftScan® Overview
10. SoftScan® is proprietary software developed and copyrighted by Robotic Engineering, LLC. It records all loss-of-metallic-area indications for inclusion into a report and for further evaluation, if necessary.
11. When the tablet is connected to the internet, SoftScan© can transfer test data to a predetermined location for backup and off-site evaluation. Additional personnel can review critical instances of metallic area loss that may necessitate immediate attention.
12. SoftScan© provides both qualitative indications of damage and quantitative estimates of the percentage of cross-sectional metallic loss.
13. The accuracy of TendonScan360 in determining percentages of metallic loss on the outer surface and within the steel bundle depends on the following factors:
a. Magnetic saturation
b. Lift-off distance (i.e., the gap between the sensor and the magnetic flux in the steel)
c. Electromagnetic energy propagation
d. Signal processing
14. The SoftScan© AI module geometrically compensates for the above factors. Extensive in-house testing of defects at various locations within a mock-up tendon trains the AI algorithms to improve the accuracy of determining percentages of cross-sectional metallic loss.