Method for detecting cable force of in-service stay cables

Abstract

The invention discloses a method for detecting the cable force of an in-service stay cable. Te method comprises: step one, acquiring a static image of an in-service stay cable; step two, acquiring image coordinates of a plurality of discrete points at one in-service stay cable; step three, acquiring corrected coordinates of the discrete points of the one in-service stay cable; step four, acquiringtilt coordinates of the discrete points of the one in-service stay cable; and step five, according to an Irvine equation and the tilt coordinates, carrying out fitting on the plurality of discrete points of the one in-service stay cable to obtain an average cable force of the in-service stay cable. According to the invention, the method has the following beneficial effects: no sensor needs to bearranged at the cable and no contact with the cable is needed; and cable force detection is realized only based on the cable image.

Description

technical field [0001] The invention relates to a cable force detection technology, in particular to a method for detecting the cable force of an in-service cable stay. Background technique [0002] At present, the common methods for measuring cable force of stay cables include hydraulic jack method, pressure sensor method, frequency method, magnetic flux method, fiber grating method, etc. Among them, hydraulic jack method is generally used to control cable force during construction, and this method is used during operation It is more difficult to test the cable force, the workload is large, and the clip will be greatly damaged by repeated pulling, and the measured value can only reflect the cable force at the tension end, and the accuracy is poor; the pressure sensor method can only The tension of the cable head is measured, but when the cable is stuck during the tensioning process, the cable force at the cable head is larger and the cable force at the middle is smaller. Th...

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Problems solved by technology

[0002] At present, the common methods for measuring cable force of stay cables include hydraulic jack method, pressure sensor method, frequency method, magnetic flux method, fiber grating method, etc. Among them, hydraulic jack method is generally used to control cable force during construction, and this method is used during operation It is more difficult to test the cable force, the workload is large, and the clip will be greatly damaged by repeated pulling, and the measured value can only reflect the cable force at the tension end, and the accuracy is poor; the pressure sensor method can only The tension of the cable head is measured, but when the cable is stuck during the tensioning process, the cable force at the cable head is larger and the cable force at the middle is smaller. Therefore, it is easy to make mistakes when using the pressure sensor method to measure the cable force; Thread the sensor on the cable in advance. This method cannot be applied to bridges without embedded sensors, and the cost of sensors and testing instruments is high, so it is rarely used; the fiber grating method is mainly used for long-term real-time monitoring of bridges. It is only used as a means of bridge detection, and the cost is too high, so it is not applicable; the frequency method is relatively simple to operate, and the test cost is low, and it is the most widely used in engineering. The actual boundary conditions, sag, and bending stiffness of the stay cables do not match. In some cases, the measurement accuracy is not high, and it usually takes repeated tests to collect satisfactory waveforms, and the data collection process is long.

[0003] To sum up, the existing test methods either need to install sensors on the cables (or anchored ends), and if it is necessary to measure the cable forces of all the cables, a large number of sensors need to be deployed, and testers need to go on the bridge, and some The method is only applicable to the cable tension stage or the construction stage

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