Bridge cable force measuring device and measuring method

Abstract

The application relates to a bridge cable force measuring device and a measuring method, and belongs to the field of bridge cable force measurement. The measuring device comprises a support beam frame, a lifting device, a cable connecting mechanism fixed below the support beam frame and two cable locking mechanisms. The two cable locking mechanisms are symmetrically fixed below the support beam, and the cable connecting mechanism is arranged on the symmetry line of the two cable locking mechanisms. The lifting device comprises a lifting rope, and the lower end of the lifting rope is connected with the cable connecting mechanism. The accurate measurement of the cable force can be realized by using the rigid bar principle and the measuring device, the interference factors are few during the measurement, the measurement result is accurate, and the measuring method is simple.

Description

Technical Field

[0001] This invention belongs to the field of bridge cable tension measurement technology, specifically, it relates to a bridge cable tension measurement device and measurement method. Background Technology

[0002] Currently, most long-span bridges are cable-stayed or suspension bridges. Cable-stayed bridges are a type of bridge where the main girder is directly supported by numerous cables to the bridge towers; they are a structural system composed of compression-bearing towers, tension-bearing cables, and bending-bearing girder bodies. Suspension bridges, also known as suspension bridges, refer to bridges whose superstructure primarily bears load using cables suspended from towers and anchored to the banks or ends of the bridge. In cable-stayed bridges, the cables are the main load-bearing structure. Whether the cable tension decreases after a period of operation and whether it meets the bridge's design requirements are crucial indicators for ensuring the reliability and durability of cable-stayed bridges.

[0003] To date, the measurement of cable forces in operating bridges has mainly relied on the frequency method. However, the accuracy of the cable forces determined by the frequency method largely depends on the reliability of the cable's own parameters, such as the cable's bending stiffness, calculated length, and linear density. Deviations in any of these parameters will affect the accuracy of the cable force calculation. Summary of the Invention

[0004] In order to overcome the problems existing in the background technology, the present invention provides a bridge cable force measuring device and method, which is not affected by the bending stiffness and linear density of the cable, has fewer interference factors, and has high measurement accuracy.

[0005] To achieve the above objectives, the present invention provides a bridge cable tension measuring device and a method for measuring cable tension using the measuring device.

[0006] The measuring device includes a support beam, a lifting device, a cable connection mechanism fixed below the support beam, and two cable locking mechanisms; wherein, the two cable locking mechanisms are symmetrically fixed below the support beam, and the cable connection mechanism is arranged on the line of symmetry of the two cable locking mechanisms; the lifting device includes a lifting rope, the lower end of which is connected to the cable connection mechanism.

[0007] The measurement method includes the following:

[0008] The cable passes through the cable connection mechanism and is locked by two cable locking mechanisms. The cable connection mechanism is pulled up using a lifting rope, with the tension in the lifting rope perpendicular to the cable. The cable is pulled up multiple times, and the lifting force P of the lifting rope and the lifting displacement a of the cable are measured.

[0009] According to the formula F=η / 2×K

[0010]

[0011] The longitudinal tension F of the bridge cable was calculated using an iterative calculation method.

[0012] In the formula, F is the longitudinal tension of the cable; K is the lifting stiffness of the cable; P is the lifting force of the lifting rope; a is the lifting displacement of the cable; and η is a coefficient.

[0013] Furthermore, the lifting rope is equipped with a high-precision displacement sensor and a high-precision tension sensor; the high-precision displacement sensor reads the lifting displacement 'a' of the cable, and the high-precision tension sensor reads the lifting force 'P' of the lifting rope.

[0014] Furthermore, the supporting beam frame includes a beam plate and an upper supporting rib fixed to the upper surface of the beam plate; the lifting device also includes a connecting arm and a jack; the left end of the connecting arm is hinged to the upper supporting rib; the right end of the connecting arm is hinged to the output end of the jack, and the bottom end of the jack is hinged to the upper supporting rib; the lower end of the lifting rope is connected to the upper fixing block, and the upper end is fixed to the right end of the connecting arm; during measurement, the jack pushes out to the right, driving the right end of the connecting arm to lift, lifting the lifting rope, and providing lifting force to the cable.

[0015] Furthermore, two upper support ribs are arranged in parallel; shaft A and shaft B are provided between the two upper support ribs, and the left end of the connecting rod arm is hinged to the upper support rib through shaft A; the bottom end of the jack is hinged to the upper support rib through shaft B.

[0016] Furthermore, the cable locking mechanism is characterized in that it includes a detachably connected upper locking block and a lower locking block, with arc-shaped latches facing each other in the middle of the upper and lower locking blocks, and the two ends connected by bolts; a fixed locking block is provided on the arc-shaped latch of the upper locking block, and an arc-shaped locking block is provided on the arc-shaped latch of the lower locking block; the lower locking block is also provided with a locking bolt for raising and lowering the arc-shaped locking block, and the locking bolt is threadedly connected to the lower locking block; the upper locking block is fixedly connected to the lower end face of the beam plate.

[0017] During measurement, the cables are locked with two cable locking mechanisms, and the lifting rope passes through the lifting rope through hole opened on the beam plate without resistance and is fixedly connected to the connecting rod arm.

[0018] Furthermore, the cable connection mechanism includes an upper fixing block and a lower fixing block; the upper fixing block and the lower fixing block have arc-shaped slots in their middle parts, and the two ends are connected by bolts; the lower fixing block has a fixing locking block with an arc-shaped upper surface at the arc-shaped slot; during measurement, the cable connection mechanism clamps the cable.

[0019] Furthermore, a lower support rib connects the beam plate to the upper locking block.

[0020] Furthermore, damping material is provided on the contact surface between the cable locking mechanism and the cable.

[0021] The beneficial effects of this invention are:

[0022] This invention uses two cable locking mechanisms to lock the measuring section of the cable for cable force measurement, avoiding the influence of cable stiffness and linear density on the measurement results, resulting in high measurement accuracy. By using a cable connecting mechanism located on the center line of the two cable locking mechanisms to clamp the cable, it can be ensured that the force point of the cable is always at the center of the two cable locking mechanisms, ensuring the accuracy of the measurement results. The combination of the cable locking mechanism and the cable connecting mechanism ensures the accuracy of the measurement data and the accuracy of the calculation results. The iterative calculation method of this invention gradually calculates the actual cable force, resulting in high measurement accuracy.

[0023] The lifting device of the present invention, through the arrangement of the connecting arm and the jack, provides a lifting reaction force to the lifting device during measurement by the support beam frame. During measurement, the stability of the entire device is strong and interference factors are reduced. In addition, the lifting device of the present invention causes less damage to the outer surface and structure of the cable during the lifting process.

[0024] The measuring device of the present invention has a compact and reliable structure, good stability, simple operation, few interference factors, high detection accuracy, and can be applied to different types of cable-stayed bridges. It also has the advantages of quick installation, convenient operation, and low cost. Attached Figure Description

[0025] Figure 1 A schematic diagram showing the connection between the cable tension measuring device and the cable.

[0026] Figure 2 This is a schematic diagram of the overall structure of the cable tension measuring device of the present invention;

[0027] Figure 3 yes Figure 2 Middle side view;

[0028] Figure 4 This is a schematic diagram of the cable locking mechanism of the present invention;

[0029] Figure 5 This is a schematic diagram of the cable connection mechanism of the present invention;

[0030] Figure 6 This is a sectional view of the supporting beam frame structure of the present invention;

[0031] Figure 7 This is a schematic diagram of the lifting device structure of the present invention;

[0032] Figure 8 This is a schematic diagram illustrating the technical principle of the present invention;

[0033] Figure 9 This is a schematic diagram of the force principle of the present invention;

[0034] Figure 10This is a schematic diagram of the iterative calculation process of the present invention;

[0035] In the diagram, 001-cable locking mechanism, 002-cable connection mechanism, 003-support beam frame, 004-lifting device, 005-high-precision displacement sensor, 006-high-precision tension sensor, 007-computing device, 011-upper locking block, 012-lower locking block, 013-arc locking block, 014-adjusting bolt, 015-fixed locking block A, 021-upper fixed block, 022-lower fixed block, 023-fixed locking block B, 024-connecting bolt, 025-lifting rope, 031-lower support rib, 032-upper support rib, 041-connecting arm, 042-jack, 10-cable, 11-cable seat, 13-shaft A, 14-shaft B. Detailed Implementation

[0036] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0037] To illustrate the present invention more clearly, the following embodiments will be described in detail.

[0038] Example 1

[0039] A bridge cable tension measuring device includes a support beam, a lifting device, a cable connection mechanism 002, and two cable locking mechanisms 001.

[0040] The azimuth description used in this embodiment is attached. Figure 6 For the sake of accuracy, the directional terms used are descriptive means employed to facilitate the description of the structure of the present invention, and the scope of protection of the present invention is not limited by the directional terms.

[0041] The supporting beam frame includes a beam plate 003 and two upper support ribs 032 fixed parallel to each other on the upper surface of the beam plate 003. Shafts A13 and B14 are provided between the two upper support ribs 032. The lifting device includes a lifting rope 025, a connecting arm 041, and a jack 042. The left end of the connecting arm 041 is hinged to the upper support rib 032 via shaft A13, the bottom end of the jack 042 is hinged to the upper support rib 032 via shaft B14, and the right end of the connecting arm 041 is hinged to the output end of the jack 042. The lower end of the lifting rope 025 is fixedly connected to the upper fixing block 021, and the upper end is fixedly connected to one end of the connecting arm 041. A high-precision displacement sensor 005 and a high-precision tension sensor 006 are provided on the lifting rope 025. The high-precision displacement sensor 005 reads the lifting displacement 'a' of the cable 10, and the high-precision tension sensor 006 reads the lifting force 'P' of the lifting rope 025.

[0042] The jack 042 and connecting rod arm 041 of the lifting device 004 are fixed to the upper support rib 032 by hinge. Since the tail of the jack 042 is connected to the support beam, the support beam provides the lifting reaction force to the lifting device 004 when it is working. During measurement, the stability of the whole device is strong.

[0043] Two cable locking mechanisms 001 are symmetrically fixed below the beam 003. The cable connecting mechanism 002 is positioned on the symmetrical line of the two cable locking mechanisms 001, located at the center of the two mechanisms. When the cable connecting mechanism 002 is lifted by the lifting rope 025 to lift the cable 10, it prevents displacement of the force-bearing point of the cable 10, ensuring that the force-bearing point of the cable 10 is always located at the center of the two cable locking mechanisms 001 (as shown in the attached diagram). Figure 9 As shown in the figure, the accuracy of the measurement results can be guaranteed and interference can be avoided (the measurement method is detailed in Example 2). At the same time, since the cable measurement section is locked by the cable locking mechanism 001, the interference of the cable's linear density and stiffness on the measurement results can be avoided.

[0044] In addition, from the perspective of overall force, the positional relationship between the two cable locking mechanisms 001 and the lifting device 004 can make the support beam frame bear the force in a balanced manner, that is, the support beam frame can be more stably fixed on the cable 10, thereby improving the accuracy of the test data.

[0045] The cable locking mechanism 001 includes an upper locking block 011 and a lower locking block 012. The upper locking block 011 and the lower locking block 012 have arc-shaped latches facing each other in the middle, and their ends are connected by bolts 024. The arc-shaped latch of the upper locking block 011 has a fixed locking block 015 with an arc-shaped outer end face, and the arc-shaped latch of the lower locking block 012 has an arc-shaped locking block 013. The fixed locking block 015 and the arc-shaped locking block 013 are mainly used to lock the cable 10. Furthermore, because the fixed locking block 015 and the arc-shaped locking block 013 are arc-shaped, the contact area with the cable 10 is increased, increasing friction and making it easier to lock the cable 10 during measurement.

[0046] The lower locking block 012 is also equipped with a locking bolt 014 for raising and lowering the arc-shaped locking block 013. The locking bolt 014 is threadedly connected to the lower locking block 012 and rotatably connected to the arc-shaped locking block 013. Since rotatable connection is a common connection structure, it will not be described in detail in this embodiment. Because the size of the cable 10 being measured varies, the locking bolt 014 is provided to improve the universality of the measurement. The distance between the fixed locking block 015 and the arc-shaped locking block 013 can be changed by the locking bolt 014 to clamp cables 10 of different sizes.

[0047] The upper locking block 011 is fixedly connected to the lower end face of the beam plate 003, and a lower support rib 031 is provided between the upper locking block 011 and the beam plate 003 to increase the connection strength between the two.

[0048] The cable connection mechanism 002 includes an upper fixing block 021 and a lower fixing block 022, with the upper fixing block 021 connected to the lifting rope 025. The upper fixing block 021 and the lower fixing block 022 have arc-shaped slots at their middle portions for clamping the cable 10, and their ends are connected by bolts. The lower fixing block 022 has a locking block 023B with an arc-shaped upper surface at its arc-shaped slot. The lower fixing block 022 also has an arc-shaped locking block B023. It should be noted that the upper fixing block 021 and the lower fixing block 022 are connected by bolts, and the upper fixing block 021 and the lower fixing block 022 are used to connect to the cable 10. The locking block B023 is used to secure the cable 10.

[0049] The materials used at the contact points between the cable locking mechanism 001 and the cable connecting mechanism 002 and the cable 10 are rubber or other damping materials to protect the cable wrapping system from damage.

[0050] Example 2

[0051] The method for measuring the cable force of a bridge using the measuring device described in Example 1 includes the following steps:

[0052] Step 1: Secure the upper locking block 011 to the upper part of the cable 10, secure the lower locking block 012 to the lower part of the cable 10, and connect the upper locking block 011 and the lower locking block 012 with bolt 24.

[0053] Step 2: Rotate the locking bolt 014. The locking bolt 014 drives the arc-shaped locking block 013 to move upward, locking the cable 10.

[0054] Step 3: Secure cable 10 using cable connection mechanism 002;

[0055] Step 4: Activate jack 042. Jack 042 pushes out to the right, causing the right end of the connecting rod arm 041 to lift, lifting rope 025, and giving lifting force to cable 10.

[0056] The cable 10 is lifted multiple times, with each lift reaching a different height. High-precision displacement sensor 005 and high-precision tension sensor 006 read the lifting force and displacement data. Based on this data, the cable force is calculated using an iterative method. The calculation method and principle are as follows:

[0057] According to the rigid string principle, the longitudinal force F of the cable remains constant during the lifting process. The longitudinal force can be obtained from K = P / a and F = η / 2 × K.

[0058] Where a is the cable lifting displacement measured by high-precision displacement sensor 005; P is the lifting force measured by high-precision tension sensor 006; K is the lifting stiffness; and η is a coefficient.

[0059] The formula F = η / 2 × K reveals an important method: by measuring the lifting stiffness K, the longitudinal force F of the cable can be calculated using the formula. Since η is related to the longitudinal force F, an iterative method is used to solve the problem.

[0060] According to the above formula: Let If the longitudinal force F of the cable is constant, then λ is constant;

[0061] Since L1 = L0 - L2, Since λ is constant, ξ is constant.

[0062] The given η is obtained. The longitudinal force F of the cable is then calculated.

[0063] Where E is the elastic modulus, I is the horizontal moment of inertia of the cable section, L0 is the measurement length range of the cable, L1 is the distance of the lifting force P from the left end point, and L2 is the distance of the lifting force P from the right end point; L0 = L1 + L2 and L1 = L2.

[0064] The physical model of force in this invention is as follows: Figure 9As shown, if the longitudinal tension of the bridge cable is considered constant, lifting the bridge cable at any position in the middle will cause the cable to displace a. Within the elastic range, the lifting stiffness K, i.e. the ratio of the lifting force P to the displacement a, is a constant value.

[0065] As a preferred embodiment, the high-precision displacement sensor 005 and the high-precision tension sensor 006 are connected to a computer or other computing device. The computing device includes a data receiving module and a data processing module. The data processing module uses the aforementioned calculation formula and method to directly calculate the cable force data. Specifically, the data receiving module receives data read by the high-precision displacement sensor 005 and the high-precision tension sensor 006, and the data processing module calculates the cable force based on the data received by the data receiving module.

[0066] To demonstrate the accuracy of the measurement data of this invention, in a laboratory environment, a longitudinal preload F was applied to a local sample of the same scale as the bridge cable. The cable force of the sample was measured multiple times using the equipment and measurement method described in this invention. The average cable force of the sample was obtained as F1. After comparison, the numerical deviation between F and F1 was within 3%, which proves that the cable force measurement equipment and method described in this invention have high accuracy.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0068] In the description of this invention, it should be noted that the use of terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings. It is only for the convenience of describing this invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0069] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for measuring the cable tension of a bridge, characterized in that, Use measuring equipment. The measuring device includes a support beam, a lifting device, a cable connection mechanism fixed below the support beam, and two cable locking mechanisms; wherein, the two cable locking mechanisms are symmetrically fixed below the support beam, and the cable connection mechanism is arranged on the line of symmetry of the two cable locking mechanisms; the lifting device includes a lifting rope, the lower end of which is connected to the cable connection mechanism. The measurement method includes the following: The cable passes through the cable connection mechanism and is locked by two cable locking mechanisms; The lifting cable connection mechanism is connected by a lifting rope. When pulling up, the direction of the tension in the lifting rope is perpendicular to the cable. The cable is pulled up multiple times, and the lifting force P of the lifting rope and the lifting displacement a of the cable are measured. According to the formula F=η / 2×K The longitudinal tension F of the bridge cables was calculated using an iterative calculation method. In the formula, F is the longitudinal tension of the cable; K is the lifting stiffness of the cable; P is the lifting force of the lifting rope; and a is the lifting displacement of the cable. For coefficients; The iterative calculation process is as follows: (1) Calculate the self-weight G of the cable within the measurement length range L0; (2) Calculate the initial lifting stiffness K=P / a based on the lifting force P and lifting displacement a measured by the high-precision sensor; (3) Assume the tension F in the cable i =G / 2+i×ΔF, i is the iteration number, and ΔF is the iteration step size. (4) Calculate λ, λ = ; E is the elastic modulus of the cable, and I is the moment of inertia of the horizontal axis of the cable cross section; (5) Calculate ξ ， L0 is the measurement range of the cable, L1 is the distance of the lifting force P from the left end point, L2 is the distance of the lifting force P from the right end point, and L1 = L0 - L2. (6) Calculate η ; (7) Calculate the lifting stiffness K i ; (8) Determine the convergence condition of the iteration: |K - K i | ≤ΔK; ΔK is the allowable deviation of stiffness; If not satisfied, let i = i + 1, and return to step (3) to iterate again; If satisfied, the currently assumed cable tension F i That is, the actual longitudinal cable force F; Output the final calculated cable force F.

2. The method for measuring the cable tension of a bridge according to claim 1, characterized in that, The lifting rope is equipped with a high-precision displacement sensor and a high-precision tension sensor; the high-precision displacement sensor reads the lifting displacement 'a' of the cable, and the high-precision tension sensor reads the lifting force 'P' of the lifting rope.

3. The method for measuring the cable tension of bridge cables according to claim 2, characterized in that, The supporting beam frame includes a beam plate and an upper supporting rib fixed to the upper surface of the beam plate; the lifting device also includes a connecting rod arm and a jack; the left end of the connecting rod arm is hinged to the upper supporting rib; the right end of the connecting rod arm is hinged to the output end of the jack, and the bottom end of the jack is hinged to the upper supporting rib; the lifting rope is fixedly connected to the right end of the connecting rod arm; during measurement, the jack pushes out to the right, causing the right end of the connecting rod arm to lift, and the lifting rope provides lifting force to the cable.

4. The method for measuring the cable tension of bridge cables according to claim 3, characterized in that, Two upper support ribs are arranged in parallel; shaft A and shaft B are provided between the two upper support ribs, and the left end of the connecting rod arm is hinged to the upper support rib through shaft A; the bottom end of the jack is hinged to the beam through shaft B.

5. The method for measuring the cable tension of bridge cables according to any one of claims 1 to 4, characterized in that, The cable locking mechanism includes a detachably connected upper locking block and a lower locking block. The upper and lower locking blocks have arc-shaped latches facing each other in the middle, and their ends are connected by bolts. A fixed locking block is provided on the arc-shaped latch of the upper locking block, and an arc-shaped locking block is provided on the arc-shaped latch of the lower locking block. The lower locking block is also provided with a locking bolt for raising and lowering the arc-shaped locking block. The locking bolt is threadedly connected to the lower locking block. The upper locking block is fixedly connected to the lower end face of the beam plate. During measurement, the cables are locked with two cable locking mechanisms, and the lifting rope passes through the lifting rope through hole opened on the beam plate without resistance and is fixedly connected to the connecting rod arm.

6. The method for measuring the cable tension of a bridge according to claim 5, characterized in that, The cable connection mechanism includes an upper fixing block and a lower fixing block; the upper and lower fixing blocks have arc-shaped slots in the middle and are connected at both ends with bolts; the lower fixing block has a locking block with an arc-shaped upper surface at the arc-shaped slot; during measurement, the cable connection mechanism clamps the cable.

7. The method for measuring the cable force of a bridge according to claim 5, characterized in that, A lower support rib is provided between the beam and the upper locking block.

8. The method for measuring the cable tension of a bridge according to claim 1, characterized in that, The cable locking mechanism has damping material on the contact surface with the cable.

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