Corrosion detection in structural tendons
First Claim
1. A method, comprising:
- injecting alternating currents through a portion of a tendon assembly including a tendon extending through a duct, the tendon at least partially encased in grout filling the duct, where access to a surface of the grout is established through small holes drilled into the duct, and four electrodes are placed into the small holes with a conductive gel to establish electrical contact with the grout, the four electrodes comprising a pair of supply electrodes and a pair of reference electrodes, where the alternating currents are injected over a range of frequencies through the pair of supply electrodes on the surface of the grout;
measuring potential differences across a portion of the grout surface between the pair of reference electrodes on the surface of the grout, the potential differences measured over the range of frequencies;
determining a total impedance (Ztotal) based upon the injected alternating currents and the measured potential differences, the total impedance comprising;
Ztotal=Zelectrode,1+Zgrout,1+Zinterface,1+Zsteel+Zinterface,2+Zgrout,2+Zelectrode,2,where Zelectrode is an impedance associated with the electrical contact of each of the pair of supply electrodes in contact with the grout, Zgrout is an impedance associated with the grout between each of the pair of supply electrodes and the tendon Zinterface is an impedance associated with an interface between the grout and a surface of the tendon adjacent to each of the pair of supply electrodes, and Zsteel is an impedance associated with the tendon; and
determining a condition of the tendon based at least in part upon the total impedance.
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Accused Products
Abstract
Various examples are provided for corrosion detection in structural tendons. In one example, among others, a method includes injecting current through a portion of a tendon assembly including a tendon at least partially encased in grout, where the current is injected through the portion of the tendon assembly via contact points on a surface of the grout. A potential across the portion of the grout surface is measured and a condition of the tendon can be based at least in part upon the current and the potential. In another example, a system includes supply electrodes to inject current into grout surrounding a tendon via contact with a surface of the grout, sensor electrodes to measure a potential difference between the supply electrodes, and an impedance detection device to determine an impedance of the tendon based at least in part upon the injected current and the potential difference.
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Citations
14 Claims
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1. A method, comprising:
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injecting alternating currents through a portion of a tendon assembly including a tendon extending through a duct, the tendon at least partially encased in grout filling the duct, where access to a surface of the grout is established through small holes drilled into the duct, and four electrodes are placed into the small holes with a conductive gel to establish electrical contact with the grout, the four electrodes comprising a pair of supply electrodes and a pair of reference electrodes, where the alternating currents are injected over a range of frequencies through the pair of supply electrodes on the surface of the grout; measuring potential differences across a portion of the grout surface between the pair of reference electrodes on the surface of the grout, the potential differences measured over the range of frequencies; determining a total impedance (Ztotal) based upon the injected alternating currents and the measured potential differences, the total impedance comprising;
Ztotal=Zelectrode,1+Zgrout,1+Zinterface,1+Zsteel+Zinterface,2+Zgrout,2+Zelectrode,2,where Zelectrode is an impedance associated with the electrical contact of each of the pair of supply electrodes in contact with the grout, Zgrout is an impedance associated with the grout between each of the pair of supply electrodes and the tendon Zinterface is an impedance associated with an interface between the grout and a surface of the tendon adjacent to each of the pair of supply electrodes, and Zsteel is an impedance associated with the tendon; and determining a condition of the tendon based at least in part upon the total impedance. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system, comprising:
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a pair of supply electrodes configured to inject alternating currents through a portion of a tendon assembly including a tendon extending through a duct, the tendon at least partially encased in grout filling the duct, where access to a surface of the grout is established through small holes drilled into the duct, and where the pair of supply electrodes are placed into a first pair of small holes with a conductive gel to establish electrical contact with the grout and the alternating currents are injected over a range of frequencies through the pair of supply electrodes on the surface of the grout; a pair of reference electrodes configured to measure potential differences across a portion of the surface of the grout between the pair of reference electrodes, where the pair of reference electrodes are placed into a second pair of small holes with a conductive gel to establish electrical contact with the grout, and the potential differences are measured over the range of frequencies; and an impedance detection device configured to; determine a total impedance (Ztotal) based upon injected alternating currents and measured potential differences, the total impedance comprising;
Ztotal=Zelectrode,1+Zgrout,1+Zinterface,1+Zsteel+Zinterface,2+Zgrout,2+Zelectrode,2,
where Zelectrode is an impedance associated with the electrical contact of each of the pair of supply electrodes in contact with the grout, Zgrout is an impedance associated with the grout between each of the pair of supply electrodes and the tendon, Zinterface is an impedance associated with an interface between the grout and a surface of the tendon adjacent to each of the pair of supply electrodes, and Zsteel is an impedance associated with the tendon; anddetermine a condition of the tendon based at least in part upon the total impedance. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification