Abstract
It is important to inspect bridge cables to insure the safety of the bridge, especially to test its loss of metallic cross-sectional area (LMA). A novel magnetic testing method for the LMA that the magnetic energy directly imposes on the bridge cable is proposed, which has advantages over the magnetic flux measurement used by traditional main-flux and return-flux methods. Its equivalent magnetic circuit is obtained, too. Furthermore, according to the magnetic Kirchhoff's Law and Taylor expansion series, the theoretic model is obtained by ignoring the higher order and used to analyse the proposed magnetic testing method. Finally, it is verified experimentally and shown good resolution.