Magnetic imaging of reinforcing steel
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A new nondestructive evaluation technique is proposed to image steel reinforcement in reinforced concrete structures. One imposes a static magnetic field on a reinforced concrete member and measures the distortion of that field due to the magnetization of the reinforcement. The distribution of magnetization within the member is determined by inverting linearized fundamental equations of magnetostatics. A second set of equations, involving the ambient magnetic field and the magnetic susceptibility of steel, relates the magnetization to the volume of steel. Simple finite-element simulations were performed to investigate the performance of the reconstruction algorithm. The present version of the algorithm differentiated clearly between widely-spaced cubes of steel and air. The reconstructions were less successful when the cubes were adjacent. Some areas that deserve further development were identified. The magnetostatic principles underlying the imaging technique could also be applied to locate ferromagnetic objects for other applications.
Key wordsImaging nondestructive evaluation magnetism reinforcing steel
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- 1.V. M. Malhotra and N. J. Carino,Handbook on Nondestructive Testing of Concrete (CRC Press, Boca Raton, 1991).Google Scholar
- 2.M. H. Nayfeh and M. K. Brussel,Electricity and Magnetism (Wiley, New York, 1985).Google Scholar
- 3.G. F. Pla, M. O. Eberhard, and P. H. Eberhard,Imaging of Rein-, forced Concrete (University of Washington, Dept. of Civil Engineering, Report No. SGEM 93-1, 1993).Google Scholar
- 4.D. J. Griffiths,Introduction to Electrodynamics (Prentice Hall, Englewood Cliffs, 1989).Google Scholar
- 5.David R. Lide, ed.Handbook of Chemistry and Physics, 73rd Ed. (CRC Press, Boca Raton, 1992–1993).Google Scholar
- 6.R. Blum and D. E. Roller,Physics (Holden-Day, San Francisco, 1981).Google Scholar
- 7.E. Hensel,Inverse Theory and Applications for Engineers (Prentice Hall, Englewood Cliffs, 1991).Google Scholar