Method and device for measuring cable force

Abstract

The invention discloses a method and a device for measuring a cable force. The device comprises a pin shaft and an ear plate, wherein an axial through hole is arranged in the axial axle wire of the pin shaft, two ends of the axial through hole are respectively and symmetrically provided with a transmitting end and a receiving end of an optical measurement system, a measurement plane of the optical measurement system is coplanar with the axial axes of the pin shaft and the action direction of load, and the ear plate is provided with a limit device to be connected with the pin shaft. On the basis that the pin shaft has the characteristics of being even in material and completely and linearly elastic under the stress state, the cable force of an inhaul cable is confirmed by the measurement of the tinny deformation of the pin shaft of a connecting node under the action of the cable force and the linear relationship between the cable force and the deformation. The method and the device provided by the invention are nondestructive testing technologies, thereby being wide in application range.

Description

technical field [0001] The invention relates to the field of construction detection, in particular to a method and device for measuring cable force. Background technique [0002] In the prior art, the cable force measurement method mainly includes the tension jack measurement method; the pressure sensor measurement method; the frequency vibration measurement method; the electromagnetic measurement method; [0003] Tension jack measurement method, because the pressure gauge itself has the characteristics of excessively fast deflection of the pointer, easy deviation, severe pointer vibration at high pressure, and artificial random errors in the readings, it cannot be used for the measurement of the cable force after the building structure is formed. Dynamic measurement is also not suitable for long-term online force measurement. The measured cable force only represents the cable force at the tension end. [0004] Pressure sensor measurement method; [0005] Disadvantages: 1...

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Problems solved by technology

[0005] Disadvantages: 1. The cost is too high; 2. It can only measure the tension of the cable head; 3. The durability of the sensor has not been verified in the actual project; 4. The scope of application is small, and it must be installed on the anchorage and the cable hole pad Between the boards, it is inconvenient to install the cable-stayed bridge that has been built; 5. Due to the large size of the pressure sensor, it will have a great impact on the appearance of the building

At the same time, it is difficult to automatically calculate the nth order natural frequency of the steel cable or the frequency difference Δf between two adjacent orders by using the spectrogram

Therefore, the result of measuring the cable force by the frequency method is related to various factors such as the installation position of the vibration pickup, whether the cable is vibrating, the span, sag, slope and boundary conditions of the tested cable, and the signal processing is relatively complicated. 24 / 7 monitoring is not possible

[0009] 2. When the vibration frequencies of the adjacent two orders of the structure are very similar, it will be very difficult to use the frequency vibration method to measure the cable force

Therefore, the frequency vibration method is only suitable for simple cable system (single cable) structures, and for complex cable system (cable group) structures, there is a large error in the measurement results

[0010] 3. The frequency vibration method is only applicable to the measurement of the force of the cable after the tensioning is completed, and it will not be possible to measure the force of the cable during the tensioning process.

Therefore, cable force measurements during passive cable construction will not be able to measure

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