Estimation and Analysis of Cable Tension Based on Frequency Method

A frequency method was proposed to analyze cable tension from measured natural frequencies according to cable tension monitoring of acable stayed bridge during construction. Xinzao Pearl River Grand Bridge was chosen as an example. A geometrical calculation simulation model was established to compare measured cable tension to theoretical cable tension during construction. This paper introduces several cable tension test methods. The principle and theoretical derivations under certain conditions, the method of which fundamental vibration frequency is deduced by dominating vibration frequency, the influence of boundary conditions, bending stiffness, and cable sag on the frequency method testing, and the practical application of frequency method were discussed. A spatial finite element model was established based on finite element software MIDAS. The application of the forward-analysis iterative method was considered to analyze the cable tension during construction. Then the cable tension test method and analysis principle were explored. Finally, it was shown that measured cable tension based on the frequency method was accurate. The measured value is approximately equal to the theoretical value. The experimental error was within the permitted range. The accuracy and reliability of the frequency method was effectively confirmed. The cable tension test for the similar bridges during construction was compatibly applied.