Study On Cable Force Test Method Of Cable-stayed Bridges

As an important force-bearing member in a cable-stayed bridge system,the cable force directly affects the overall internal force distribution and structural deformation of the structure.The structural force can be optimized by adjusting the cable force,so accurate measurement of the structure at all stages.It is of great significance to ensure the safety of the structure by pulling the cable and understanding its working status.In this paper,the stay cable is taken as the research object,and the cable force test results are analyzed by the sag method,frequency method and magnetic flux method.The main research work is as follows:(1)By reviewing a large number of related literatures at home and abroad,the research status of sag method,frequency method and magnetic flux method in cable force measurement field is analyzed,and the cable force measurement methods are reviewed and summarized.(2)The basic theory of measuring the cable force by the sag method is introduced,and the practical calculation formulas for the sag and cable force of any cable section under the action of the dead weight and tension of the cable are derived through static analysis.The finite element software ANSYS was used to analyze the relationship between the cable force and sag of a cable to verify the reliability of the formula.Based on the model test data,the calculation results of the sag formula were compared with the test results,which proved the accuracy of the formula.(3)The basic theory of cable force measurement by frequency method and several cable vibration models are introduced,and the influence of factors such as bending stiffness,boundary conditions,shock absorbers,slope and sag on cable force is analyzed.At the same time,the practical formula for testing the cable force of the frequency method is summarized.The short cable is calculated and analyzed by the cable force formula,and the calculation error of each cable force formula is analyzed.Finally,the cable force calculations of the cables are performed using the frequency method formula and the sag formula,respectively,further verifying the reliability of the sag formula.(4)Starting from the basic principle of the magnetic flux method,the magnetic effect of the substance and the working principle of the magnetic flux sensor are summarized,which provides a theoretical basis for the subsequent experiments.Through the experimental analysis of the magnetic properties of different tension cables,the accuracy of testing the cable force of a single cable by the magnetic flux method is studied.