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Sensing Technology for Damage Assessment of Sign Support Structures

Zhu, Xuan (2011) Sensing Technology for Damage Assessment of Sign Support Structures. Master's Thesis, University of Pittsburgh.

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    Abstract

    In the last few years the use of guided ultrasonic waves (GUWs) for the health monitoring of engineering structures increased rapidly, with the most recent studies focusing on the application of GUWs to complex structures or under varying environmental conditions. In fact, the health monitoring of complex structures is complicated because of reflections, scattering, and mode conversion. In addition, sensitivity to temperature and surface wetting can degrade the performance of a GUW-based structural health monitoring system.This thesis presents the results of an experimental investigation where GUWs and the Electro-mechanical Impedance (EMI) method were used for the health monitoring of a truss, which was part of a highway variable message structure removed from service and tested in laboratory. The monitoring strategy proposed here combines the advantages of GUWs and EMI with the extraction of defect-sensitive features to perform a multivariate diagnosis of damage. The effectiveness of the presented approach is tested by monitoring the propagation of waves along one of the main chords of the truss and by observing the onset and growth of two artificial cracks. The ability to diagnose the presence of these defects located around the welds that join two diagonal angular members to the chord is discussed.In the last portion of the thesis, the results from field application are presented. Two overhead sign support structures deployed along I-279 were monitored by using the proposed SHM methodology developed in laboratory.


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    Details

    Item Type: University of Pittsburgh ETD
    ETD Committee:
    ETD Committee TypeCommittee MemberEmailORCID
    Committee ChairRizzo, Piervincenzopir3@pitt.edu
    Committee MemberTo, Albert Chi Fualbertto@pitt.edu
    Committee MemberHarries, Kent Akharries@pitt.edu
    Title: Sensing Technology for Damage Assessment of Sign Support Structures
    Status: Unpublished
    Abstract: In the last few years the use of guided ultrasonic waves (GUWs) for the health monitoring of engineering structures increased rapidly, with the most recent studies focusing on the application of GUWs to complex structures or under varying environmental conditions. In fact, the health monitoring of complex structures is complicated because of reflections, scattering, and mode conversion. In addition, sensitivity to temperature and surface wetting can degrade the performance of a GUW-based structural health monitoring system.This thesis presents the results of an experimental investigation where GUWs and the Electro-mechanical Impedance (EMI) method were used for the health monitoring of a truss, which was part of a highway variable message structure removed from service and tested in laboratory. The monitoring strategy proposed here combines the advantages of GUWs and EMI with the extraction of defect-sensitive features to perform a multivariate diagnosis of damage. The effectiveness of the presented approach is tested by monitoring the propagation of waves along one of the main chords of the truss and by observing the onset and growth of two artificial cracks. The ability to diagnose the presence of these defects located around the welds that join two diagonal angular members to the chord is discussed.In the last portion of the thesis, the results from field application are presented. Two overhead sign support structures deployed along I-279 were monitored by using the proposed SHM methodology developed in laboratory.
    Date: 26 January 2011
    Date Type: Completion
    Defense Date: 20 August 2010
    Approval Date: 26 January 2011
    Submission Date: 09 November 2010
    Access Restriction: No restriction; The work is available for access worldwide immediately.
    Patent pending: No
    Institution: University of Pittsburgh
    Thesis Type: Master's Thesis
    Refereed: Yes
    Degree: MSCE - Master of Science in Civil Engineering
    URN: etd-11092010-112835
    Uncontrolled Keywords: EMI; Sign Support Structure; Structural Health Monitoring; Ultrasonic Guided Wave
    Schools and Programs: Swanson School of Engineering > Civil and Environmental Engineering
    Date Deposited: 10 Nov 2011 15:04
    Last Modified: 11 May 2012 10:34
    Other ID: http://etd.library.pitt.edu/ETD/available/etd-11092010-112835/, etd-11092010-112835

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