Study on Monitoring Cable Force of Cable-stayed Bridge during Construction by Vibration Frequency Method

In order to study the cable force characteristics of cable-stayed Bridges in different construction stages, a study on monitoring cable force of cable-stayed Bridges based on vibration frequency method is proposed. According to the string vibration theory, the test formula of vibration frequency method is listed, and the control error of measured cable force is specified. The vibration frequency measurement method is adopted, and the natural vibration frequency of the cable is obtained by analyzing the signal received by the vibration receiver, and the cable force is calculated. According to the characteristics of cable construction conditions, the cable force monitoring stages are divided into three stages: completion of assembly and closure of steel box girder, completion of second phase cable adjustment and completion of the whole bridge. The cable force results of main span and side span of cable-stayed bridge under different working conditions are analyzed. Combining the error between measured cable force and theoretical cable force, the cable law characteristics under construction conditions are analyzed.The results show that the error value of cable force monitored by vibration frequency method is that the assembling and closing working condition is larger than the second-stage cable adjusting working condition than the complete bridge working condition. The error between the measured cable force and the theoretical cable force is controlled within 10%. After several cable adjustments, the cable force shows a uniform change trend, and the bridge construction is in a safe and controllable state.