Method for Measuring the Structural Health of a Civil Structure

• US 20090132199A1
• Filed: 12/04/2008
• Published: 05/21/2009
• Est. Priority Date: 12/04/2008
• Status: Active Grant

• Current Assignee: Laura A. Solliday, Payne, John-Michael Family Trust
• Original Assignee: Laura A. Solliday, Payne, John-Michael Family Trust
• Inventors: Payne, John M., Parker, David H.
• Granted Patent: US 7,895,015 B2
• Time in Patent Office: Days
• US Class Current: 702/150
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105

Abstract

Methods are disclosed wherein the structural health of a civil structure, such as, but not limited to, a bridge or the like is measured by electronic distance measurement from a plurality of stable locations to a plurality of cardinal points on the structure in a methodical manner. By measuring the coordinates of the cardinal points, the dynamic and long-term static behavior of the structure provide an indication of the health of the structure. Analysis includes; comparison to a Finite Element Model (FEM), comparison to historical data, linearity, hysteresis, symmetry, creep, damping coefficient, and harmonic terms.

Claims

1. A method comprising:

(a) providing means for measuring a plurality of cardinal points fixed to a bridge comprising;

at least one retroreflector attached to each of said cardinal points, a plurality of electronic distance measurement instruments mounted in a stable reference coordinate system, and a central processor coordinating said plurality of electronic distance instruments;

(b) measuring at least;

a first range from a first electronic distance measurement instrument to a first cardinal point, a second range from a second electronic distance measurement instrument to said first cardinal point, and a third range from a third electronic distance measurement instrument to said first cardinal point;

(c) storing at least said first, second, and third ranges;

(d) computing a first three dimensional coordinate of said first cardinal point, in said stable reference coordinate system, based at least in part on said first, second, and third ranges;

(e) determining at least a first structural health parameter of said bridge based at least in part on said first three dimensional coordinate;

(f) memorializing said first structural health parameter.

2. The method of claim 1 further comprising;

(a) measuring at least;

a fourth range from said first electronic distance measurement instrument to a second cardinal point, a fifth range from said second electronic distance measurement instrument to said second cardinal point, and a sixth range from said third electronic distance measurement instrument to said second cardinal point;

(b) storing at least said fourth, fifth, and sixth ranges;

(c) computing a second three dimensional coordinate of said second cardinal point, in said stable reference coordinate system, based at least in part on said fourth, fifth, and sixth ranges;

(d) determining at least a second structural health parameter of said bridge based at least in part on said second three dimensional coordinate;

(e) memorializing said second structural health parameter.

3. The method of claim 1 further comprising;

(a) measuring at least;

a seventh range from a fourth electronic distance measurement instrument to a third cardinal point, an eighth range from a fifth electronic distance measurement instrument to said third cardinal point, and a ninth range from a sixth electronic distance measurement instrument to said third cardinal point;

(b) storing at least said seventh, eighth, and ninth ranges;

(c) computing a third three dimensional coordinate of said third cardinal point, in said stable reference coordinate system, based at least in part on said seventh, eighth, and ninth ranges;

(d) determining at least a third structural health parameter of said bridge based at least in part on said third three dimensional coordinate;

(e) memorializing said third structural health parameter.

4. The method of claim 2 further comprising;

(a) determining at least a fourth structural health parameter of said bridge based at least in part on said first three dimensional coordinate and said second three dimensional coordinate;

(b) memorializing said fourth structural health parameter.

5. The method of claim 3 further comprising;

(a) determining at least a fifth structural health parameter of said bridge based at least in part on said first three dimensional coordinate and said third three dimensional coordinate;

(b) memorializing said fifth structural health parameter.

6. The method of claim 1 further comprising;

(a) performing steps a-f of claim 1 at a first epoch in time;

(b) performing steps a-f of claim 1 at a second epoch in time;

(c) determining at least a sixth structural health parameter of said bridge based at least in part on said first epoch in time and said second epoch in time;

(d) memorializing said sixth structural health parameter.

7. The method of claim 6 wherein the time between said first and second epochs in time is greater than one day.

8. The method of claim 6 wherein the time between said first and second epochs in time is less than one day.

9. The method of claim 6 wherein the time between said first and second epochs in time is less than ½

the period of the fundamental frequency of the natural vibrations of said bridge.

10. The method of claim 6 wherein at least one parameter affecting the bridge is changed between said first and second epochs in time.

11. The method of claim 1 further comprising;

(a) measuring at least a tenth range from said first electronic distance measurement instrument to said second electronic distance measurement instrument;

(b) storing at least said tenth range;

(c) using said tenth range in step d of claim 1.

12. The method of claim 1 wherein the absolute uncertainty of said first, second, and third ranges is less than 1 mm.

13. The method of claim 1 wherein the absolute uncertainty of said first, second, and third ranges is less than 0.1 mm.

14. The method of claim 6 wherein the relative uncertainty of said first, second, and third ranges, between said first and second epochs in time, is less than 1 mm.

15. The method of claim 6 wherein the relative uncertainty of said first, second, and third ranges, between said first and second epochs in time, is less than 0.1 mm.

16. The method of claim 6 wherein the relative uncertainty of said first, second, and third ranges, between said first and second epochs in time, is less than 0.01 mm.

17. The method of claim 1 wherein, for said first cardinal point, said at least one retroreflector attached to each said cardinal point, is a first multidirectional retroreflector.

18. A method comprising:

(a) providing means for measuring a plurality of cardinal points fixed to a building comprising;

at least one retroreflector attached to each of said cardinal points, a plurality of electronic distance measurement instruments mounted in a stable reference coordinate system, and a central processor coordinating said plurality of electronic distance instruments;

(b) measuring at least;

a first range from a first electronic distance measurement instrument to a first cardinal point, a second range from a second electronic distance measurement instrument to said first cardinal point, and a third range from a third electronic distance measurement instrument to said first cardinal point;

(c) storing at least said first, second, and third ranges;

(d) computing a first three dimensional coordinate of said first cardinal point, in said stable reference coordinate system, based at least in part on said first, second, and third ranges;

(e) determining at least a first structural health parameter of said building based at least in part on said first three dimensional coordinate;

(f) memorializing said first structural health parameter.

19. A method comprising:

(a) providing means for measuring a plurality of cardinal points fixed to a crane comprising;

at least one retroreflector attached to each of said cardinal points, a plurality of electronic distance measurement instruments mounted in a stable reference coordinate system, and a central processor coordinating said plurality of electronic distance instruments;

(b) measuring at least;

a first range from a first electronic distance measurement instrument to a first cardinal point, a second range from a second electronic distance measurement instrument to said first cardinal point, and a third range from a third electronic distance measurement instrument to said first cardinal point;

(c) storing at least said first, second, and third ranges;

(d) computing a first three dimensional coordinate of said first cardinal point, in said stable reference coordinate system, based at least in part on said first, second, and third ranges;

(e) determining at least a first structural health parameter of said crane based at least in part on said first three dimensional coordinate;

(f) memorializing said first structural health parameter.