Accounting for the Rigidity of Steel Cables When Assessing Their Tension Force Based on the Results of Measuring the Frequency of Natural Vibrations

The results of a previously performed survey of steel cables of a cable-stayed crossing where the tension force was determined based on the frequency of their transverse vibrations are considered. The features of the methodology for measuring the natural frequencies of rope vibrations are revealed concerning the method of excitation ща vibrations, their orientation, and the volume of an informative sample of recorded frequencies. The physical model underlying the measurement technique does not take into account the elastic bending reaction of the cable and viscous friction. It is shown that taking into account these factors allows one not only to increase the accuracy of measuring the tension force, but also opens up a possibility for detecting cable defects. For example, the breakage of cable fibers, its thinning as a result of corrosion or abrasion could lead to a decrease in bending stiffness. A change in the state of the cable lubricant or the penetration of liquid into the cable leads to a change in the damping coefficient of its vibrations. The results of the study can be used to create systems for monitoring the condition of steel cables.