Validation value of cable force using the accelerometer

Abstract

Cable is a tensile element on cable stayed bridges that works to support the load on the bridge deck due to the traffic load. In the design, it has been calculated the maximum load that can be received by each cable based on dead load, live load or environmental load. When the bridge operates, it is necessary to monitor the behavior of the bridge structure due to the work load based on the time function. It is very important for the bridge management to examine the cable forces that occur in real time, so that it can be immediately known if there is a cable force exceeding the maximum limit. One of the sensor tools that can be used to determine the frequency of the cable is accelerometer. The frequency data from accelerometer are calculated into the approach of formulas developed by Wei-Hua Hu, 2005. In this study, calculation cable forces consider the effect of sag cable or bending stiffness using Wei-Hua Hu formula. As a control data in cable force calculations, it used measurement data conducted by consultants. From the results for cable C7 located on left side of bridge needs to be re-tested. This happens because the value of the resulting cable force does not show similarity with the right-side (cable C7 located on right side). The cable C7 in left side of bridge has a frequency value of 1.24 and generate cable forces tends to decrease, where it should be increase for cables forces values. For other cable forces, the value of the cable force obtains a range difference between 0.28% - 9.23%. Longer cable such as cable M7, the cable force formula is less influenced by bending stiffness effects in calculation. In other words, the stiffness of the cable is small or does not affect the cable force. As for shorter cables in cables C2 and M2, the bending stiffness of the cables affects the calculation of the cable force.