Claims
- 1. A method for monitoring the failure of tensioned reinforcements in a structure comprising the steps of:
- (a) positioning a plurality of acoustic or seismic detectors about the structure in a known arrangement and in close proximity to the structure;
- (b) processing signals from the detectors;
- (c) identifying those of said signals which are due to the failure of a tensioned reinforcement in the structure;
- (d) identifying at least one signal received at more than two sensors after passage from an origin through a medium to such sensors;
- (e) determining the relative times of arrival of said identified signal at more than two sensors;
- (f) calculating the origin of said identified signal from the difference of its time of arrival at each of said more than two sensors.
- 2. The method as claimed in claim 1, wherein the steps of processing and identifying those of said signals which are due to failure of a tensioned reinforcement further comprise: analyzing said signals from the detectors for frequency contents; and indentifying said signals as being due to failure of a tensioned reinforcement only when the frequency content of said signals exhibits frequencies above a predetermined frequency-threshold and voltages above a predetermined voltage-threshold.
- 3. The method as claimed in claim 1, wherein the step of processing further comprises: converting the signals from the detectors by Fourier transforms.
- 4. The method as claimed in claim 3, wherein said signals are identified as being due to the failure of a tensioned reinforcement in the structure if such signals are a plurality of nearly simultaneous acoustic emissions originating from sources located substantially on a line along a tensioned reinforcememt cable.
- 5. The method as claimed in claim 1, wherein said signals are identified as being due to the failure of a tensioned reinforcement in the structure if such signals are a plurality of nearly simultaneous acoustic emissions originating from sources located substantially on a line along a tensioned reinforcement cable.
- 6. The method as claimed in claim 1, wherein a said signal is identified as being due to the failure of tensioned reinforcement in a structure when it exhibits a short burst having spectral components at frequencies greater than 6 kHz.
- 7. A method as claimed in claim 1, in which said detectors are placed in contact with the structure.
- 8. A method as claimed in claim 1, in which said signals are acoustic signals.
- 9. A method as claimed in claim 1, in which said signals are seismic signals.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 08/436,986, filed May 8, 1995, abandoned, which is a continuation of application Ser. No. 08/081,878, filed Jun. 25, 1993, abandoned.
US Referenced Citations (15)
Foreign Referenced Citations (3)
Number |
Date |
Country |
8200893 |
Mar 1982 |
DEX |
58-108419 |
Jun 1983 |
JPX |
62-034051 |
Feb 1987 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Muspratt,M.A, "Strain Measurment in Reinforced Concrete Slabs", Jul. 1969, Strain pp. 152-156. |
Dunn, S.E. et al. "Acoustic Emission Characterization of Corrosion Induced Damage in Reinforced Concrete" Jul. 1984, Corrosion pp. 339-343. |
Continuations (1)
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Number |
Date |
Country |
Parent |
81878 |
Jun 1993 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
436986 |
May 1995 |
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