Structural monitoring system

• US 5,421,204 A
• Filed: 06/08/1993
• Issued: 06/06/1995
• Est. Priority Date: 06/08/1993
• Status: Expired due to Term

• Current Assignee: Karl J. Svaty Jr
• Original Assignee: Karl J. Svaty Jr
• Inventors: Svaty, Karl J. Jr.
• Primary Examiner(s): Raevis, Robert
• Application Number:
  US08/073,593
• Time in Patent Office: 728 Days
• Field of Search: 73/1 DV, 73/786, 73/577, 73/579, 73/582, 340/870.02, 340/870.03
• US Class Current: 73/786
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00

Abstract

A method and device are provided for sensing and collecting structural deformation data on structures over time to permit structural integrity analysis of the structure and determination of structure life expectancy and need for repair or reconstruction of the structure.

Claims

1. The method of monitoring a structure, a bridge or building for determining the condition of the structure over time comprising the steps of:

Step a;

analyzing mathematically the structure to determine a point of a substantial structural loading action;

Step b;

attaching a strain gauge to said analyzed point;

Step c;

establishing a baseline of strain gauge frequency output and amplitude output in response to said structural action as a result of an applied load;

Step d;

monitoring said action of the structure during use;

Step e;

recording strain gauge frequency output and amplitude output produced in response to said structural action detected by said strain gauge as a result of structure use;

Step f;

comparing said recorded frequency and amplitude output with said baseline output in order to determine the structural condition of said structure with the passage of time, and

Step g;

repeating steps d-f.

2. The method as claimed in claim 1, wherein said strain gauge is connected with a second strain gauge for temperature compensation.

3. A method for determining changes in the structural deterioration of a structure comprising the steps of:

analyzing with a mathematical model the structure to determine a point of the structure displaying substantial axial tension-compression in response to loading;

attaching a strain gauge sensor to said analyzed point;

monitoring sensor frequency output and sensor amplitude output generated by an actual loading of the structure;

determining from said sensor frequency output and said sensor amplitude output a baseline natural frequency of vibration of the structure at a time soon after sensor attachment;

redetermining the natural frequency of the structure from said sensor frequency output and said sensor amplitude output at a time after the determination of said baseline; and

comparing the redetermined natural frequency of the structure with said baseline natural frequency of the structure to analyze deterioration in the structure.

4. The method as claimed in claim 3, further comprising the step of transmitting said monitored frequency and amplitude of said action to a remote location for determination and comparison of said structure natural frequency with said baseline.