Assessment of Cable Tension Using Vibration Based Methodologies for Wireless Structural Health Monitoring

In Health Monitoring of the cable supported bridges, estimation of the cable tension influences the accuracy of the monitoring system. The purpose of this study is to prove the vibration based methodologies in conjunction with dynamic cable theory can be used to measure the tension force in cables. The idea being that the accelerations from the cable vibrations have embedded frequencies which can be extracted using Fast Fourier Transform and processed using the computer-aided software. After the accelerations are processed and the frequencies are extracted and organized, the cable tension can be calculated using dynamic cable theory and cable properties. Numerical studies were carried out on a cable with known tensile force using ABAQUS, to determine the natural frequencies. Adopting the flat taut string theory, the beam theory, Fang theory, Zui's theory and Wei-Xin Ren's cable force was assessed from natural frequency. A MATLAB script was developed to estimate the tension force of the cable for the above theories.