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Development of a Magnetic Field Sensor System for Nondestructive Evaluation of Reinforcing Steel in Prestressed Concrete Bridge Members

Fernandes, Bertrand
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1352760825

Abstract Details

2012, Doctor of Philosophy in Engineering, University of Toledo, Electrical Engineering.
Nondestructive evaluation of prestressed concrete mainly includes inspection of the condition of the prestressing strands for load rating. This thesis presents a magnetic inspection system to measure main magnetic flux (MMF) and magnetic leakage flux (MFL) signals, to evaluate the condition of prestressing stands. A proof-of-concept has been established using a prototype electromagnet-sensor, showing a direct relationship between the cross-sectional area of the strand and the magnitude of magnetic field induced in it. A field test of a box-beam bridge was conducted using both MMF and MFL detection techniques separately. This led to the realization of a comprehensive MMF-MFL electromagnet-sensor system for inspection of prestressed steel in concrete. A computer aided simulation model was created to model the magnetic field signals and aid in better understanding of the electromagnet-sensor. This model is also useful for generating expected magnetic field signals from magnetization of different strand size and configuration setups and thus, helps in making corrosion estimations. The MMF-MFL signal detection concept was evaluated using the existing electromagnet-sensor in a laboratory setup and on prestressed box-beams obtained from a demolished bridge. It was able to identify corrosion and defects such as breaks or fractures in prestressing strands. For this magnetic inspection system to become practical, certain modifications such as redesign of the magnetic field generated by the magnet to have higher resolution have been suggested. Other features such as accurate measurement of pole face to strand distance and weight reduction have been discussed. The overall outcome of this research has shown that magnetic field signals can be useful to detect hidden corrosion in prestressed box-beams.
Vijay K. Devabhaktuni, PhD (Committee Chair)
Douglas K. Nims, PhD (Committee Co-Chair)
Mansoor Alam, PhD (Committee Member)
Roger J. King, PhD (Committee Member)
Brian W. Randolph, PhD (Committee Member)
132 p.
Civil Engineering; Electrical Engineering
Box-Beam Bridge; Nondestructive Testing and Evaluaiton; Prestressed Strand; Electromagnet Sensor; Main Magnetic Flux; Magnetic Flux Leakage

Recommended Citations

Citations

  • Fernandes, B. (2012). Development of a Magnetic Field Sensor System for Nondestructive Evaluation of Reinforcing Steel in Prestressed Concrete Bridge Members [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1352760825

    APA Style (7th edition)

  • Fernandes, Bertrand. Development of a Magnetic Field Sensor System for Nondestructive Evaluation of Reinforcing Steel in Prestressed Concrete Bridge Members. 2012. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1352760825.

    MLA Style (8th edition)

  • Fernandes, Bertrand. "Development of a Magnetic Field Sensor System for Nondestructive Evaluation of Reinforcing Steel in Prestressed Concrete Bridge Members." Doctoral dissertation, University of Toledo, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1352760825

    Chicago Manual of Style (17th edition)

toledo1352760825
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© 2012, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.