A bridge cable force increment measurement device and measurement method

Abstract

The present invention provides a bridge cable force increment measurement device and measurement method, wherein the measurement device includes a cable force tester, a transmission layer and a display layer; the cable force tester includes an upper clamping ring, a lower clamping ring, four connecting rods and four strain gauges, the upper clamping ring and the lower clamping ring are connected by four connecting rods, the four connecting rods are arranged at intervals and surround the circumference of the clamping through hole, and a strain gauge is installed in the middle of each connecting rod; the transmission layer includes a collector, a 4G / 5G signal transmitter and a cloud, the collector is connected to the four strain gauges, and the collector is also connected to the cloud through the 4G / 5G signal transmitter; the display layer includes a terminal device, and the terminal device is connected to the cloud; the measurement method is based on the above-mentioned measurement device. The measurement device of the present invention can overcome the disadvantage that strain gauges cannot be installed on cables, has the advantages of simple principle and high test accuracy, and the measurement method can meet the dynamic real-time monitoring of cable force of cable-type bridges, filling the gap in the current real-time monitoring of cable force increment of cable-type bridges.

Description

Technical Field

[0001] The invention relates to the technical field of cables, and in particular to a bridge cable force increment measuring device and a measuring method. Background Art

[0002] Bridge cables generally include the hangers and tie rods of arch bridges, the cables of cable-stayed bridges, and the main cables and hangers of suspension bridges. This type of bridge is widely used because of its large spanning capacity, beautiful appearance, clear structural force, and economical and practical advantages. Whether in the construction stage, the completion stage, or the operation stage, the cable force increment is a must-test item for this type of bridge. At present, the commonly used cable force test methods include the frequency method, the magnetic flux method, and the pressure ring method. Among them, the frequency method is a widely used cable force measurement method. This method indirectly obtains the cable force through the relationship between frequency and cable force. Although this method is simple to test, it has a large error, especially for short cables. Its error can often cover up the increase in cable force. The magnetic flux method is still in the development stage. The current application results show that its error is also large and cannot be used in the test of the cable force increment of bridge cables. The pressure ring method has high test accuracy and can meet the test requirements of cable force increment. However, this method requires the pressure ring to be set in advance when the cable is installed. This method cannot be used for existing bridges, and the price of this method is very expensive and cannot be popularized on a large scale. In view of the pain points existing in the above industries, it is very necessary and urgent to propose a bridge cable force increment measurement device and measurement method with simple testing and high testing accuracy. Summary of the invention

[0003] In order to achieve the above object, the technical solution adopted by the present invention is:

[0004] A bridge cable force increment measurement device comprises a cable force tester, a transmission layer and a display layer; the cable force tester comprises an upper clamping ring, a lower clamping ring, four connecting rods and four strain gauges, the upper clamping ring and the lower clamping ring are parallel and opposite, and the middle part of both has a clamping through hole for the cable to pass through, the aperture of the clamping through hole is slightly smaller than the cable diameter, the upper clamping ring and the lower clamping ring are connected by four connecting rods, the four connecting rods are arranged at intervals and surround the circumference of the clamping through hole, and a strain gauge is installed in the middle part of each connecting rod; the transmission layer comprises a data collector, a 4G / 5G signal transmitter and a cloud, the data collector is connected to the four strain gauges, and the data collector is also connected to the cloud through the 4G / 5G signal transmitter; the display layer comprises a terminal device, and the terminal device is connected to the cloud.

[0005] Preferably, the upper clamping ring and the lower clamping ring have the same structure, the upper clamping ring is in the shape of a circular ring and is evenly divided into two semicircular rings, both ends of each semicircular ring in the arc length direction are welded with ear plates, each ear plate is provided with a bolt hole, and the two semicircular rings are connected into a circular ring by inserting high-strength bolt threads into the bolt holes, and the inner ring of the circular ring is the clamping through hole.

[0006] Preferably, a thread structure is engraved on the wall of the clamping through hole.

[0007] Preferably, the connecting rod is made of metal or alloy, and its cross section in the vertical length direction is a rectangular structure, and the cross section size is smaller than the cross section size of the cable.

[0008] Preferably, the terminal device is a computer, a mobile phone or a tablet.

[0009] In addition, the present invention also provides a bridge cable force increment measurement method, the measurement method adopts the above-mentioned bridge cable force increment measurement device for measurement, and comprises the following steps:

[0010] (1) Calibration of cable force tester;

[0011] (2) Install a cable force tester on the cable to be tested;

[0012] (3) Instrument connection, where all strain gauges of the cable force tester are connected to the data acquisition instrument of the transmission layer, the data acquisition instrument of the transmission layer is connected to the cloud via a 4G / 5G signal transmitter, and the terminal equipment of the display layer is wirelessly connected to the cloud;

[0013] (4) Setting parameters related to the cable to be tested, specifically setting the parameters of the cable to be tested on the terminal device, the parameters mainly including the elastic modulus E and the cross-sectional area A of the cable to be tested;

[0014] (5) Collection of cable force increments.

[0015] Preferably, in step (1), when the elastic modulus E and the cross-sectional area A of the cable to be tested are unknown, the cable force tester is calibrated by testing before the cable is installed. The specific steps are as follows:

[0016] 1) Select a section of cable of the same model as the cable to be tested;

[0017] 2) Install a cable force tester in the middle of the selected cable;

[0018] 3) Install both ends of the selected cable on the MTS universal testing machine;

[0019] 4) Apply different levels of load to the MTS universal testing machine and measure the strain data on the cable force tester at the same time;

[0020] 5) The tensile stiffness of the cable can be calibrated by the following formulas (1) and (2):

[0021] ΔF=EAε a (1)

[0022]

[0023] Where ΔF is the cable force increment, EA is the tensile stiffness of the cable, and ε a is the average strain, ε i is the strain value of the ith strain gauge.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention provides a bridge cable force increment measurement device, which has the characteristics of simple structure and clear deformation, can be easily installed on existing cables, and can be reused;

[0026] (2) The cable force tester of the present invention, by using the consistent relationship between the deformation of the connecting rod and the deformation of the cable, converts the traditional direct test of the cable deformation into the test of the connecting rod deformation, thereby overcoming the disadvantage of being unable to install strain gauges on the cable, and has the advantages of simple principle and high test accuracy;

[0027] (3) The present invention provides a method for measuring the incremental force of bridge cables. The method uses a 4G or 5G network to achieve real-time data transmission, so that the system can meet the dynamic real-time monitoring of the cable force of cable-stayed bridges, filling the gap in the current real-time monitoring of the incremental force of cable-stayed bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the cable force tester of the present invention.

[0029] Figure 2 It is a schematic diagram of the system structure of the measuring device of the present invention.

[0030] Main component symbols

[0031] In the figure: upper clamping ring 1, lower clamping ring 2, connecting rod 3, bolt 4, strain gauge 5, cable tension tester 10, collector 20, 4G / 5G signal transmitter 30, cloud 40, terminal device 50.

[0032] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0033] See also Figure 1 to Figure 2 In a preferred embodiment of the present invention, a bridge cable tension increment measurement device includes a cable tension tester 10, a transmission layer and a display layer.

[0034] The cable tension tester 10 includes an upper clamping ring 1, a lower clamping ring 2, four connecting rods 3 and four strain gauges 5. The upper clamping ring 1 and the lower clamping ring 2 are parallel and opposite to each other. The middle part of the two has a clamping through hole for the cable to pass through. The aperture of the clamping through hole is slightly smaller than the cable diameter. The upper clamping ring 1 and the lower clamping ring 2 are connected by four connecting rods 3. The four connecting rods 3 are arranged at intervals and surround the circumference of the clamping through hole. A strain gauge 5 is installed in the middle part of each connecting rod 3. The cable tension tester 10 of the present invention clamps the cable to be tested through the clamping through holes of the upper clamping ring 1 and the lower clamping ring 2, connects the upper clamping ring 1 and the lower clamping ring 2 through the connecting rod 3, and deforms synchronously when the upper clamping ring 1 and the lower clamping ring 2 are displaced by the force on the cable. The deformation can be detected by the strain gauge 5 on the connecting rod 3. The deformation of the cable can be known through the detection result of the strain gauge 5. In this embodiment, the upper clamping ring 1 and the lower clamping ring 2 have the same structure. The upper clamping ring 1 is in the shape of a ring and is evenly divided into two semicircular rings. Both ends of each semicircular ring in the arc length direction are welded with ear plates. Each ear plate is provided with 4 bolt holes. The two semicircular rings are connected into a ring by inserting 4 high-strength bolts into the 4 bolt holes. The inner ring of the ring is the clamping through hole. Preferably, the hole wall of the clamping through hole is engraved with a threaded structure to increase the friction force of the upper clamping ring 1 and the lower clamping ring 2 clamping the cable. Preferably, the connecting rod 3 is made of metal or alloy, specifically a metal or alloy with light weight, moderate hardness and strong fatigue resistance, and its cross section in the vertical length direction is a rectangular structure, and the cross section size is smaller than the cross section size of the cable, specifically the cross section size of the connecting rod 3 is much smaller than the cross section size of the cable, so that the deformation of the connecting rod 3 is synchronized with the deformation of the cable, and the tension shared by the connecting rod 3 can be ignored.

[0035] The transmission layer includes a collector 20, a 4G / 5G signal transmitter 30 and a cloud 40. The collector 20 is connected to the four strain gauges 5 to collect the strain signals detected by the strain gauges 5 and convert the electrical signals collected by the strain gauges 5 into digital signals. The collector 20 is also connected to the cloud 40 via the 4G / 5G signal transmitter 30 to transmit the digital signals to the cloud 40 via the 4G / 5G signal transmitter 30. The display layer includes a terminal device 50, which is connected to the cloud 40, specifically in a wireless connection mode, to receive data from the cloud 40 in real time through the Internet, and set the relevant parameters of the cable to be tested on the terminal device 50. The parameters are combined with the data transmitted from the cloud 40 to obtain the cable force increment of the cable to be tested; preferably, in this embodiment, the terminal device 50 is a computer or a mobile phone or a tablet.

[0036] In the present invention, the measuring principle of the cable force increment to be measured is as follows:

[0037] The upper clamping ring 1 and the lower clamping ring 2 of the cable force tester 10 are clamped with the cable force to be measured. Since the cross-sectional size of the connecting rod 3 is much smaller than the cross-sectional size of the cable, the deformation of the connecting rod 3 and the cable can be realized synchronously, and the tension shared by the connecting rod 3 is negligible. Then, the cable force increment ΔF is as follows:

[0038] ΔF=EAε a (1)

[0039] Where EA is the tensile stiffness of the cable, ε a is the average strain, which is obtained by the following formula:

[0040]

[0041] In the formula, ε i is the strain value of the i-th strain gauge 5.

[0042] Based on the above principle, it can be known that after the cable tension tester 10 clamps the cable, the strain value ε measured by the strain gauge 5 is i , the strain values ​​ε measured by all strain gauges 5 are combined i , substituting into formula (2), we can get the average strain value ε a , when the tensile stiffness of the cable to be tested is known, the calculated average strain value ε a Substituting into equation (1), the cable force increment ΔF of the cable can be obtained. Therefore, the measuring device provided by the present invention can be used to measure the cable force increment of the bridge cable, and the measurement is simple and convenient to use.

[0043] Based on the above measurement principle and measurement device, the present invention also provides a bridge cable force increment measurement method, the measurement method adopts the above bridge cable force increment measurement device for measurement, and comprises the following steps:

[0044] (1) Calibration of the cable force tester 10;

[0045] (2) Installing a cable force tester 10 on the cable to be tested;

[0046] (3) Instrument connection, wherein all strain gauges 5 of the cable force tester 10 are connected to the data acquisition instrument 20 of the transmission layer, the data acquisition instrument 20 of the transmission layer is connected to the cloud 40 via the 4G / 5G signal transmitter 30, and the terminal device 50 of the display layer is wirelessly connected to the cloud 40;

[0047] (4) Setting parameters related to the cable to be tested, specifically setting parameters of the cable to be tested on the terminal device 50, the parameters mainly being the elastic modulus E and the cross-sectional area A of the cable to be tested;

[0048] (5) Collection of cable force increments.

[0049] Preferably, in step (1), when the elastic modulus E and the cross-sectional area A of the cable to be tested are unknown, the cable force tester 10 is calibrated by testing before the cable is installed. The specific steps are as follows:

[0050] 1) Select a section of cable of the same model as the cable to be tested;

[0051] 2) Installing a cable force tester 10 in the middle of the selected cable;

[0052] 3) Install both ends of the selected cable on the MTS universal testing machine;

[0053] 4) Apply different levels of load to the MTS universal testing machine and measure the strain data on the cable force tester 10 at the same time;

[0054] 5) The tensile stiffness of the cable can be calibrated by the following formulas (1) and (2):

[0055] ΔF=EAε a (1)

[0056]

[0057] Where ΔF is the cable force increment, EA is the tensile stiffness of the cable, and ε a is the average strain, ε i is the strain value of the i-th strain gauge 5.

[0058] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A bridge cable force increment measurement method, characterized in that: The measuring method adopts a bridge cable force increment measuring device for measurement, and the bridge cable force increment measuring device comprises a cable force tester, a transmission layer and a display layer; the cable force tester comprises an upper clamping ring, a lower clamping ring, four connecting rods and four strain gauges, the upper clamping ring and the lower clamping ring are parallel and opposite, and the middle part of the two has a clamping through hole for the cable to pass through, the aperture of the clamping through hole is slightly smaller than the cable diameter, the upper clamping ring and the lower clamping ring are connected by four connecting rods, the four connecting rods are arranged at intervals and surround the circumference of the clamping through hole, and a strain gauge is installed in the middle part of each connecting rod; the transmission layer comprises a collector, a 4G / 5G signal transmitter and a cloud, the collector is connected to the four strain gauges, and the collector is also connected to the cloud through the 4G / 5G signal transmitter; the display layer comprises a terminal device, and the terminal device is connected to the cloud; The measuring method comprises the following steps: (1) Calibration of the cable force tester: When the elastic modulus E and cross-sectional area A of the cable to be tested are unknown, the cable force tester is calibrated by test before the cable is installed. The specific steps are as follows: 1) Select a section of cable of the same model as the cable to be tested; 2) Install a cable force tester in the middle of the selected cable; 3) Install both ends of the selected cable on the MTS universal testing machine; 4) Apply different levels of load to the MTS universal testing machine and measure the strain data on the cable force tester at the same time; 5) The tensile stiffness of the cable can be calibrated by the following formulas (1) and (2): ΔF=EAε a (1) Where ΔF is the cable force increment, EA is the tensile stiffness of the cable, and ε a is the average strain, ε i is the strain value of the i-th strain gauge; (2) Install a cable force tester on the cable to be tested; (3) Instrument connection, where all strain gauges of the cable force tester are connected to the data acquisition instrument of the transmission layer, the data acquisition instrument of the transmission layer is connected to the cloud via a 4G / 5G signal transmitter, and the terminal equipment of the display layer is wirelessly connected to the cloud; (4) Setting parameters related to the cable to be tested, specifically setting the parameters of the cable to be tested on the terminal device, the parameters mainly including the elastic modulus E and the cross-sectional area A of the cable to be tested; (5) Collection of cable force increments.

2. A bridge cable force increment measurement method according to claim 1, characterized in that: The upper clamping ring and the lower clamping ring have the same structure. The upper clamping ring is in the shape of a circular ring and is divided into two semicircular rings. Ear plates are welded at both ends of each semicircular ring in the arc length direction. A bolt hole is opened on each ear plate. The two semicircular rings are connected into a circular ring by inserting high-strength bolts through the bolt holes. The inner ring of the circular ring is the clamping through hole.

3. A bridge cable force increment measurement method according to claim 1, characterized in that: The hole wall of the clamping through hole is engraved with a thread structure.

4. A bridge cable force increment measurement method according to claim 1, characterized in that: The connecting rod is made of metal, and its cross section in the vertical length direction is a rectangular structure, and the size of the cross section is smaller than the cross section size of the cable.

5. A bridge cable force increment measurement method according to claim 1, characterized in that: The terminal device is a computer.

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