Continuous monitoring of reinforcements in structures

• US 6,170,334 B1
• Filed: 07/13/1998
• Issued: 01/09/2001
• Est. Priority Date: 06/25/1993
• Status: Expired due to Term

• Current Assignee: Pure Technologies Limited (Xylem, Inc.)
• Original Assignee: Pure Technologies Limited (Xylem, Inc.)
• Inventors: Paulson, Peter O.
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US09/119,064
• Time in Patent Office: 911 Days
• Field of Search: 340/566, 340/690, 702/14, 702/15, 702/16, 702/17, 702/18, 702/36, 702/41, 702/56, 735/79, 735/81, 735/82, 735/84, 735/87, 735/94, 738/01, 73D/IG.1
• US Class Current: 73/587
• CPC Class Codes: E04C 5/08 Members specially adapted to be used in prestressed constructions production of reinforced objects in general B28B23/00; prestressed structures produced in situ E04G21/12
• CPC Class Codes: G01H 1/00 Measuring characteristics of vibrations in solids by using direct conduction to the detector G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G01N 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/02458 Solids in solids, e.g. granules
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/38 by time filtering, e.g. using time gates
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14
• CPC Class Codes: G01V 1/001 Acoustic presence detection
• CPC Class Codes: G01V 1/20 Arrangements of receiving elements, e.g. geophone pattern

Abstract

Method and apparatus for detecting failure of tensioned reinforcements in a structure by means of a plurality of acoustic or seismic detectors disposed about the structure in a known arrangement, processing signals from the detectors to determine frequency contents and origins, and identifying simultaneous signals as due to the failure of tensioned reinforcements in the structure when they meet spectral and origin criteria.

Claims

1. An apparatus for detecting the location of failure of a tensioned reinforcement in a structure comprising

(a) a plurality of detectors positioned about the structure in a known arrangement and in close proximity to the structure, the detectors being responsive to acoustic energy or seismic energy or a combination thereof to produce a signal;

(b) a processor comprising means for identifying whether a signal is caused by failure of a tensioned reinforcement in the structure;

(c) means coupling said means for identifying each one of said detectors so that the central processor means receives signals from said detectors along with identification of the detectors sending such signals,

(d) timing means for determining the relative time of arrival of the energy from a signal due to failure of a tensioned reinforcement at each of at least two such detectors;

(e) calculating means associated with said central processor means to calculate the origin of such signal from its relative time of arrival at said at least two detectors and

(f) reporting means to indicate the failure of a tensioned reinforcement at said origin.

3. Apparatus as claimed in claim 1, in which the processor comprises means for detecting substantially simultaneous signals which are acoustic signals having originals along a linear reinforcement cable.

2. Apparatus for monitoring the failure of tensioned reinforcements in a plurality of separate structures, comprising:

a first detector group which comprises at least three acoustic or seismic detectors in each separate structure;

a second detector group which comprises one detector in each separate structure;

analog-to-digital converter means for converting signals from said first detector group to digital representations;

means for processing the digital representations of signals from said first detector group to determine whether such signals indicate failure of a tensioned reinforcement; and

means for processing the digital representations of signals from the second detector group to determine the particular separate structure which is the source of such signals.

4. Apparatus as claimed in claim 2, in which the means for processing the digital representations of signals from said first detector group comprises means for detecting substantially simultaneous signals which arc acoustic signals having originals along a linear reinforcement cable.