Evaluation of concrete cover thickness and steel bar diameter - interpretation of leakage flux locus curves with neutal networks vs. analytical methods

In civil engineering, the need for reliable ndt-techniques exists to measure the concrete cover thickness above the reinforcing steel bars. The technique to achieve this developed at the IZFP Saarbrücken, in contrast to the other magnetic techniques, measures and evaluates the amplitude-locus curve of the magentic field with the help of a magneitc field sensor. This sensor scans the surface between the two pole shoes of a permanent magnet yoke. The presentation discusses two ways of interpretation of the leakage flux locus curve, resulting from this device: the analytical way and neural data analysis.