The Cable Tension Test Research Of Parallel Strand Stayed-cable Based On Frequency Method

Cable-stayed cable tension is an important indicator of bridge construction control, frequency method is commonly used in the cable tension test. This paper uses Nanyang Guangwu Bridge as engineering background, take some studies on Frequency method which is applied to the parallel strand cable tension test, Mainly include the following aspects:(1) This paper summarizes the existing academic research achievements about the corresponding relationship of the cable force and frequency, Puts forward the practical calculation formulas for cable tension which consider the influence of factors such as cable sag, bending stiffness, boundary conditions and slope. In addition, This paper also discusses briefly that how to determine the parameter of cable and judge the frequency order in the calculation process.(2) Parallel strand cable is discrete each other at both ends, but they contact in the middle area as the cable tension is not uniform. Therefore, people doubt the feasibility of frequency method measure the parallel strand cable tension. This paper concluded that the frequency method can be used to measure the parallel strand cable tension through Establishing contact coupling model of cable and contrasting the obtained vibration frequency.(3) When using frequency method to measure the cable tension of parallel strand cable, we always place the acceleration sensor directly on the HDPE casing directly, but the HDPE casing’s quality is light and it’s force at both ends is very small, it will contact with the cable body in the middle part. Considering the above questions, through modeling the cable-HDPE casting and contrasting the obtained vibration frequency,This paper concluded that we can’t ignore the influence of HDPE casing in the cable tension test and can calculate the cable tension according to the weight of the HDPE casing to modify the line density of cable.(4) In order to verify the above conclusions, This paper has carried on the tension experiment of single strand,7strand,7strand plus casing, and then proves the above conclusion well by analyzing the experimental data.(5) To apply the above conclusion on cable tension test of parallel strand cables of Guangwu bridge, which get the satisfactory results.