Monitoring of the Internal Force of the Flexible Components by Vibration Method

摘要

The vibration method is used widely to estimate the cable force based on its relationship to frequency. The accuracy and the applicability of the vibration method can be improved through a more robust incorporation of the influential factors and a precise measurement of the frequency. An advanced vibration method was proposed in this paper to minimize the error of the cable force in long-term monitoring. The influential parameters on the accuracy of the vibration method including the flexural stiffness, sag-span ratio, inclination, and the boundary conditions of the cable were analyzed. Then the factors resulting in the error of the frequency data acquisition were presented. Based on the results, the conditions when those influential factors should be taken into account were determined, and the range of the error caused by the inaccuracies of the frequency measurement was given. A comprehensive optimized approach was finally established to determine the cable force based on the previous analysis. The accuracy and the feasibility of the proposed method were confirmed by a successful monitoring of a cable stayed bridge and a special shaped steel arch bridge.