METHOD AND DEVICE FOR THE NON-DESTRUCTIVE EXAMINATION OF STEEL CABLES IN ANCHORAGES

摘要

The invention relates to a method and device for the non-destructive examination of steel cables in anchorages. The inventive method is based on a magnetic flux measurement. A magnetic field B is induced in the cable (2) to be examined by means of a coil (1). The magnetic flux lines (3) are concentrated in the steel as compared to the surroundings due to the higher magnetic permeability of the steel and extend approximately in parallel to the wire axis. The flux of the magnetic field can be measured on the front face (4) of every undamaged wire (2) through the end face (4) of the cable (2). If, as shown in Figure 1b, a break (5) perpendicular to the longitudinal axis of the cable (2) is present between the coil (1) and the end face (4) of the wire (2), the magnetic flux is weaker or reduced on the end face (4) of the wire (2). The break width of the gap (5) influences the magnetic flux, measured on the end face (4) of the wire (2). For a cable that consists of a plurality of wires the measurement of the magnetic flux on the end face (4) of every single wire (2) can be used to determine whether the wire is still in a good condition or if it is cracked or completely broken.