Method for testing a prestressed concrete conduit
First Claim
1. A method for testing a prestressed concrete conduit which comprises a hollow concrete body tightly wrapped with a prestressing wire, the method comprising the steps of:
- (a) serially inducing an elastic wave having a shear wave component into the conduit at at least three different inducing locations along the surface of the conduit;
(b) sensing each shear wave component induced at each of the inducing locations with at least one acoustic sensor disposed at a first fixed sensing site proximate to the conduit;
(c) correlating the relationship between (i) at least one parameter of each shear wave component induced at each inducing location and sensed by the acoustic sensor, and (ii) and the distance between said each inducing location and the acoustic sensor; and
(d) comparing the correlations produced in step (c) with a standard correlation to identify structural discontinuities in the conduit.
1 Assignment
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Accused Products
Abstract
A method is provided for testing prestressed concrete pipe. In the method, elastic waves are serially induced at at least three different inducing locations along the surface of the conduit. The shear wave component of each induced elastic wave is detected by at least one, and preferably two, acoustic sensors disposed at fixed sensing sites along the conduit. The relationship between at least one parameter of each induced shear wave and the distance between each inducing location and the acoustic sensor(s), are correlated and compared with standard correlations to identify structural discontinuities in the conduit. In a typical example of the method, elastic waves are induced using a mechanical hammer at multiple inducing sites around a multiplicity of annuli along the length of the conduit. Each annulus is separated from adjoining annuli by 2-4 feet.
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Citations
39 Claims
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1. A method for testing a prestressed concrete conduit which comprises a hollow concrete body tightly wrapped with a prestressing wire, the method comprising the steps of:
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(a) serially inducing an elastic wave having a shear wave component into the conduit at at least three different inducing locations along the surface of the conduit; (b) sensing each shear wave component induced at each of the inducing locations with at least one acoustic sensor disposed at a first fixed sensing site proximate to the conduit; (c) correlating the relationship between (i) at least one parameter of each shear wave component induced at each inducing location and sensed by the acoustic sensor, and (ii) and the distance between said each inducing location and the acoustic sensor; and (d) comparing the correlations produced in step (c) with a standard correlation to identify structural discontinuities in the conduit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for testing a prestressed concrete conduit which comprises a round, hollow concrete body having a first end and a second end and being tightly wrapped with a prestressing wire, the method comprising the steps of:
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(a) serially inducing an elastic wave having a shear wave component into the conduit at at least three different inducing locations along the surface of the conduit wherein at least three of the inducing locations are at different distances d1, d2 and d3 from such first end of the concrete body; (b) sensing each shear wave component induced at each inducing location by a first acoustic sensor disposed at a first fixed sensing site proximate to the first end of the concrete body and in physical contact with the conduit and by a second acoustic sensor disposed at a second fixed sensing site proximate to the second end of the concrete body and in physical contact with the conduit; (c) correlating the relationship between (i) at least one parameter of each shear wave component induced at each inducing location and sensed by the acoustic sensors, and (ii) and a distance parameter which is mathematically related to each combined distance between each inducing location and each of the acoustic sensors; and (d) comparing the correlations produced in step (c) with a standard correlation to identify structural discontinuities in the conduit. - View Dependent Claims (36, 37, 38, 39)
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Specification