Magnetic field measurements on bridges and development of a mobile SQUID system

The paper describes the application of Non-Destructive Testing for the detection of ruptures in the prestressing reinforcement. These damages can be detected by the non- destructive and contactless magnetic stray field measuring method. The paper presents the underlying physical principle and the results of measurements on bridges. Furthermore, the development of a multi-channel system utilizing Superconducting Quantum Interference Devices as most sensitive magnetic field detectors will be reported. First laboratory measurements indicate the potential of this new technique.