Method for measuring cable length of cable-stayed bridge

Abstract

The application provides a method for measuring the length of a cable of a cable-stayed bridge, comprising the following steps: S1, an electromagnetic component is arranged on the top end of the cable, a sliding groove component is detachably arranged on the bottom end of the cable, and a steel wire rope is arranged along the length direction of the cable; one end of the steel wire rope is an A end, which is detachably connected with the electromagnetic component, and the other end is a C end, which is slidably penetrated through the sliding groove component and connected with a tension meter; S2, when the tension meter is pulled to the position where the steel wire rope is parallel to the cable, a lowest point of the steel wire rope parallel to the cable is marked as a B point, the tension value F of the tension meter is recorded, meanwhile, a point where the cable is parallel to the B point is recorded as a B' point, the distance between the B' point and the bottom end of the cable is measured and recorded as L1; S3, the distance between the A end and the B point of the steel wire rope is measured and recorded as L2; and the length of the cable is L=L1+L2. The application can accurately measure the length of the cable.

Description

Technical Field

[0001] This invention relates to the field of cable-stayed bridge cable measurement technology, specifically to a method for measuring the length of cable-stayed bridge cables. Background Technology

[0002] Before replacing cables in a cable-stayed bridge, it is necessary to determine the cable length. Because the cables of a cable-stayed bridge have a sag effect under normal working conditions (that is, the cables will sag under their own weight load), the cables are not straight lines but curves under normal working conditions, which makes it very difficult to accurately measure the cable length.

[0003] Currently, the following measurement methods are commonly used:

[0004] First, use a total station to measure the spatial coordinates of two points, A at the top of the cable and B at the bottom of the cable:

[0005] A(x a ,y a ,z a ), B(x) b ,yb,zb);

[0006] Secondly, calculate the straight-line distance D between points A and B according to equation (1). AB :

[0007]

[0008] Then, the sag effect of the cable length is corrected using equation (2) to obtain the sag correction value ΔL of the cable length. f :

[0009]

[0010] In equation (2), W is the weight per unit length of the cable; L0 is the base length of the cable, i.e., the straight-line distance D between points A and B. AB L x L0 is the horizontal projection; T is the tension in the cable.

[0011] Finally, the cable length L is calculated using equation (3). AB :

[0012] L AB =D AB +ΔL f (3);

[0013] The above measurement methods require testing a large number of parameters on-site (such as A(x)). a ,y a ,z a B(x) b ,y b ,zb The measurement methods described above, which involve W and T, introduce numerous sources of error. Furthermore, the theoretical formulas used to calculate the cable length are insufficient to accurately reflect real-world conditions.

[0014] In conclusion, it is of great significance to provide a method for measuring the cable length of cable-stayed bridges, so as to reduce the measurement error and make the measured value of the cable length as close as possible to the actual situation. Summary of the Invention

[0015] The purpose of this invention is to provide a method for measuring the cable length of a cable-stayed bridge, and the specific technical solution is as follows:

[0016] A method for measuring the cable length of a cable-stayed bridge includes the following steps:

[0017] Step S1: An electromagnetic component is attached to the top of the cable-stayed bridge cable, and a sliding groove component is detachably attached to the bottom of the cable-stayed bridge cable. A steel wire rope is attached along the length of the cable-stayed bridge cable. One end of the steel wire rope is end A, which is detachably connected to the electromagnetic component, and the other end is end C, which slides through the sliding groove component and is connected to the tension gauge.

[0018] Step S2: Turn on the power to the electromagnetic component, so that the electromagnetic component is attached to the top of the cable, and the A end of the wire rope is flush with the top of the cable. Pull the tension gauge until the wire rope is parallel to the cable. At this time, mark the lowest point on the wire rope that is parallel to the cable as point B, and record the tension value F of the tension gauge. At the same time, record the point on the cable that is flush with point B as point B′, and measure the distance from point B′ of the cable to the bottom of the cable, and record it as L1.

[0019] Step S3: Disconnect the power supply to the electromagnetic component, remove the electromagnetic component from the top of the cable-stayed bridge cable, and then remove the wire rope from the electromagnetic component; unfold the wire rope in the horizontal plane and fix its A end, pull the C end with the tension gauge until the tension value is F, measure the distance from the wire rope from the A end to the B point, and record it as L2; ​​the cable length is L = L1 + L2.

[0020] Optionally, the electromagnetic component includes an electromagnet, a wire, a power supply, and a control switch. The wire is wound around the electromagnet, and its two ends are respectively connected to the positive and negative terminals of the power supply. The control switch is disposed on the wire.

[0021] Optionally, the electromagnetic component may also include a remote control for adjusting the opening and closing of the control switch.

[0022] Optionally, the electromagnetic component further includes a traction rope, one end of which is connected to the electromagnet, and the other end is a free end; a connecting loop is provided at the top of the cable for the free end of the traction rope to pass through.

[0023] Optionally, the chute assembly includes a first chute unit, which includes a first base and a first hemisphere; the first base is detachably mounted on the cable; an mounting groove for mounting the first hemisphere is provided on the first base, and a first arc-shaped chute for the wire rope to slide through is provided on the first hemisphere; the central axis of the first arc-shaped chute is coplanar with the straight line containing the length of the cable;

[0024] The bending direction of the first arc-shaped groove is opposite to that of the cable, and the minimum distance between the wire rope and the cable when the wire rope passes through the first arc-shaped groove is equal to the distance between end A of the wire rope and the top of the cable.

[0025] Optionally, the chute assembly further includes a second chute unit disposed between the first chute unit and the bottom end of the cable. The second chute unit includes a second base, a second hemisphere, a support body, and a connector. The second base is detachably mounted on the cable. The support body is mounted on the second base and has a protrusion. The connector is connected to the second hemisphere and has a groove adapted to the protrusion. A second arc-shaped chute is provided on the second hemisphere for the wire rope to slide through. The central axis of the second arc-shaped chute is coplanar with the straight line containing the length of the cable.

[0026] The second arc-shaped groove bends toward the cable, and the maximum distance between the wire rope and the cable when the wire rope passes through the second arc-shaped groove is greater than the minimum distance between the wire rope and the cable when the wire rope passes through the first arc-shaped groove.

[0027] Optionally, the shape of the bump may include a square, a triangle, or a trapezoid.

[0028] Optionally, both the first base and the second base are detachably mounted on the cable using structural adhesive.

[0029] Optionally, lubricant may be applied to the first and second arc-shaped grooves.

[0030] Optionally, the diameter of the wire rope is 0.1-0.2 mm.

[0031] The application of the technical solution of the present invention has at least the following beneficial effects:

[0032] This invention provides a method for measuring the cable length of a cable-stayed bridge. In steps S1-S3, by combining an electromagnetic component, a sliding groove component, a steel wire rope, and a tension gauge, only the tension values ​​F, L1, and L2 need to be measured on-site, reducing the number of parameters required for on-site testing. Furthermore, L1 and L2 are obtained by testing the steel wire rope and cable under parallel conditions. Therefore, this invention can measure the cable length more accurately, ensuring that the measured cable length closely reflects the actual situation.

[0033] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0034] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0035] Figure 1 This is a schematic diagram of the cable-stayed bridge cable under normal working conditions in an embodiment of the present invention (the dashed lines in the figure represent straight lines);

[0036] Figure 2 This is a schematic diagram of the structure of the electromagnetic component in an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure in an embodiment of the present invention, showing the electromagnetic component being adsorbed and disposed on the top of the cable;

[0038] Figure 4 This is a schematic diagram of the structure of the chute assembly disposed on the bottom end of the cable in an embodiment of the present invention;

[0039] Figure 5 yes Figure 4 Left view of the first chute unit (the wire rope is also shown in the figure);

[0040] Figure 6 yes Figure 4 Left view of the second chute unit (the wire rope is also shown in the figure);

[0041] Figure 7 This is a schematic diagram of the structure of a cable-stayed bridge cable length measuring device in operation according to an embodiment of the present invention (the dashed line in the figure represents a straight line);

[0042] Among them, 1. cable, 2. electromagnet, 3. wire, 4. power supply, 5. control switch, 6. wire rope, 7. first chute unit, 7.1. first base, 7.2. first hemisphere, 7.2.1. first arc-shaped chute, 8. second chute unit, 8.1. second base, 8.2. second hemisphere, 8.2.1. second arc-shaped chute, 8.3. support body, 8.3.1. protrusion, 8.4. connector, 8.4.1. groove, 9. tension gauge, P. bridge tower, Q. main beam. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0044] Example:

[0045] See Figure 1 , 3 -4 and 7, a method for measuring the cable length of a cable-stayed bridge, comprising the following steps:

[0046] Step S1: An electromagnetic component is attached to the top of the cable-stayed bridge cable 1 (connected to the bridge tower P of the cable-stayed bridge through a steel sleeve), and a sliding groove component is detachably attached to the bottom of the cable-stayed bridge cable 1 (connected to the main beam Q of the cable-stayed bridge through a steel sleeve). A steel wire rope 6 is attached along the length of the cable-stayed bridge cable 1. One end of the steel wire rope 6 is end A, which is detachably connected to the electromagnetic component, and the other end is end C, which slides through the sliding groove component and is connected to the tension gauge 9.

[0047] Step S2: Turn on the power supply 4 of the electromagnetic component, so that the electromagnetic component is attached to the top of the cable 1, and the A end of the steel wire rope 6 is flush with the top of the cable 1. Pull the tension gauge 9 until the steel wire rope 6 is parallel to the cable 1. At this time, mark the lowest point on the steel wire rope 6 that is parallel to the cable 1 as point B, and record the tension value F of the tension gauge 9. At the same time, record the point on the cable 1 that is flush with point B as point B′. Use a tape measure to measure the distance from point B′ of the cable 1 to the bottom of the cable 1, and record it as L1.

[0048] Step S3: Disconnect the power supply 4 of the electromagnetic component, remove the electromagnetic component from the top of the cable-stayed bridge cable 1, and then remove the steel wire rope 6 from the electromagnetic component; unfold the steel wire rope 6 in the horizontal plane and fix its A end, pull the C end with the tension gauge 9 until the tension value is F, and use a tape measure to measure the distance from the A end to the B point of the steel wire rope 6, and record it as L2; ​​the cable length of the cable 1 is L = L1 + L2.

[0049] See Figure 2 The electromagnetic component includes an electromagnet 2, a wire 3, a power supply 4, and a control switch 5. The wire 3 is wound around the electromagnet 2, and its two ends are respectively connected to the positive and negative terminals of the power supply 4. The control switch 5 is disposed on the wire 3.

[0050] The electromagnetic assembly also includes a remote control for adjusting the opening and closing of the control switch 5. The remote control adjusts the opening and closing state of the control switch 5, thereby controlling the energization and de-energization of the electromagnet 2. When the electromagnet 2 is de-energized, its attraction to the top of the cable 1 is released. (See also...) Figure 3 When electromagnet 2 is energized, it has an attractive force with the top of cable 1.

[0051] The electromagnetic component also includes a traction rope (not shown in the figure), one end of which is connected to the electromagnet 2, and the other end is a free end; a connecting ring (not shown in the figure) is provided at the top of the cable 1 for the free end of the traction rope to pass through. The operator can pull the traction rope through the free end, and under the guidance of the connecting ring, pull the electromagnetic component closer to or away from the top of the cable 1; wherein, when L2 needs to be measured, the power supply 4 of the electromagnetic component is turned on, and the electromagnetic component is pulled to the top of the cable 1 to complete the measurement operation; when the measurement of L2 is finished, the power supply 4 of the electromagnetic component is turned off, and the electromagnetic component is moved away from the top of the cable 1.

[0052] See Figure 4 and Figure 5 The chute assembly includes a first chute unit 7, which includes a first base 7.1 and a first hemisphere 7.2. The first base 7.1 is detachably mounted on the cable 1. An mounting groove for mounting the first hemisphere 7.2 is provided on the first base 7.1, and a first arc-shaped chute 7.2.1 for the wire rope 6 to slide through is provided on the first hemisphere 7.2. The central axis of the first arc-shaped chute 7.2.1 is coplanar with the straight line containing the length of the cable 1, which helps to ensure that when the wire rope 6 is pulled by the tension gauge 9, it can always be pulled along the length direction of the cable 1, so as to reduce measurement error.

[0053] The bending direction of the first arc-shaped groove 7.2.1 is opposite to that of the cable 1, and the minimum distance between the wire rope 6 and the cable 1 when the wire rope 6 passes through the first arc-shaped groove 7.2.1 is equal to the distance between end A of the wire rope 6 and the top of the cable 1, so as to ensure that the wire rope 6 is parallel to the cable 1 when the tension value is F, so as to reduce the measurement error.

[0054] See Figure 4 and Figure 6 The chute assembly further includes a second chute unit 8, which is disposed between the first chute unit 7 and the bottom end of the cable 1. The second chute unit 8 includes a second base 8.1, a second hemisphere 8.2, a support body 8.3, and a connecting body 8.4. The second base 8.1 is detachably mounted on the cable 1. The support body 8.3 is mounted on the second base 8.1, and a protrusion 8.3.1 is provided on the support body 8.3. The connecting body 8.4 is connected to the second hemisphere 8.2, and a groove 8.4.1 adapted to the protrusion 8.3.1 is provided on the connecting body 8.4. A second arc-shaped chute 8.2.1 for the wire rope 6 to slide through is provided on the second hemisphere 8.2. The central axis of the second arc-shaped chute 8.2.1 is coplanar with the straight line containing the length of the cable 1, ensuring that when the wire rope 6 is pulled by the tension gauge 9, it is always pulled along the length of the cable 1, thereby reducing measurement errors.

[0055] The second arc-shaped groove 8.2.1 bends towards the cable 1, and the maximum distance between the wire rope 6 and the cable 1 when the wire rope 6 passes through the second arc-shaped groove 8.2.1 is greater than the minimum distance between the wire rope 6 and the cable 1 when the wire rope 6 passes through the first arc-shaped groove 7.2.1. The second arc-shaped groove 8.2.1 and the first arc-shaped groove 7.2.1 are used in combination to provide multiple load-bearing points when the force gauge 9 pulls the wire rope 6, ensuring that the wire rope 6 is parallel to the cable 1, thereby reducing measurement errors.

[0056] The protrusion 8.3.1 is square in shape to prevent the support 8.3 and the connector 8.4 from sliding after they are connected.

[0057] Both the first base 7.1 and the second base 8.1 are detachably mounted on the cable 1 using structural adhesive.

[0058] Lubricant is applied to the first arc-shaped groove 7.2.1 and the second arc-shaped groove 8.2.1 to reduce the friction on the wire rope 6 and reduce the influence of friction on the tension value F, thereby reducing the measurement error when measuring L2.

[0059] The diameter of the wire rope 6 is 0.15mm, which makes it easier to reduce the weight and size of the wire rope 6, thereby reducing the friction of the first arc-shaped groove 7.2.1 and the second arc-shaped groove 8.2.1 on the wire rope 6.

[0060] This embodiment provides a method for measuring the cable length of a cable-stayed bridge. In steps S1-S3, by combining an electromagnetic component, a sliding groove component, a steel wire rope 6, and a tension gauge 9, only the tension values ​​F, L1, and L2 need to be measured on-site, reducing the number of parameters tested. Furthermore, L1 and L2 are obtained by testing the steel wire rope 6 and the cable 1 under parallel conditions. Therefore, the cable length of the cable 1 can be measured more accurately, ensuring that the measured value of the cable length closely matches the actual situation.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the cable length of a cable-stayed bridge, characterized in that, Includes the following steps: Step S1: An electromagnetic component is attached to the top of the cable-stayed bridge cable (1), a sliding groove component is detachably attached to the bottom of the cable-stayed bridge cable (1), and a steel wire rope (6) is attached along the length of the cable-stayed bridge cable (1); one end of the steel wire rope (6) is end A, which is detachably connected to the electromagnetic component, and the other end is end C, which slides through the sliding groove component and is connected to the tension gauge (9); Step S2: Turn on the power supply (4) of the electromagnetic component, so that the electromagnetic component is attached to the top of the cable (1) and the A end of the wire rope (6) is flush with the top of the cable (1). Pull the tension gauge (9) until the wire rope (6) is parallel to the cable (1). At this time, mark the lowest point of the wire rope (6) that is parallel to the cable (1) as point B, and record the tension value F of the tension gauge (9). At the same time, record the point where the cable (1) is flush with point B as point B′, and measure the distance from point B′ of the cable (1) to the bottom of the cable (1), and record it as L1. Step S3: Disconnect the power supply (4) of the electromagnetic component, remove the electromagnetic component from the top of the cable-stayed bridge cable (1), and then remove the wire rope (6) from the electromagnetic component; unfold the wire rope (6) in the horizontal plane and fix its A end, pull the C end through the tension gauge (9) until the tension value is F, measure the distance from the A end to the B point of the wire rope (6), and record it as L2; ​​the cable length of the cable (1) is L = L1 + L2.

2. The method for measuring the cable length of a cable-stayed bridge according to claim 1, characterized in that, The electromagnetic assembly includes an electromagnet (2), a wire (3), a power supply (4), and a control switch (5). The wire (3) is wound around the electromagnet (2), and its two ends are respectively connected to the positive and negative terminals of the power supply (4). The control switch (5) is disposed on the wire (3).

3. The method for measuring the cable length of a cable-stayed bridge according to claim 2, characterized in that, The electromagnetic component also includes a remote control for adjusting the opening and closing of the control switch (5).

4. The method for measuring the cable length of a cable-stayed bridge according to claim 2, characterized in that, The electromagnetic component also includes a traction rope, one end of which is connected to the electromagnet (2), and the other end is a free end; a connecting ring is provided at the top of the cable (1) for the free end of the traction rope to pass through.

5. The method for measuring the cable length of a cable-stayed bridge according to any one of claims 1-4, characterized in that, The chute assembly includes a first chute unit (7), which includes a first base (7.1) and a first hemisphere (7.2). The first base (7.1) is detachably mounted on the cable (1). An mounting groove for mounting the first hemisphere (7.2) is provided on the first base (7.1), and a first arc-shaped chute (7.2.1) for the wire rope (6) to slide through is provided on the first hemisphere (7.2). The central axis of the first arc-shaped chute (7.2.1) is coplanar with the straight line containing the length of the cable (1). The first arc-shaped groove (7.2.1) is curved away from the cable (1), and the wire rope (6) passes through the first arc-shaped groove ( 7.2.1) The minimum distance between the cable (1) and the wire rope (6) is equal to the distance between the A end of the wire rope (6) and the top end of the cable (1).

6. The method for measuring the cable length of a cable-stayed bridge according to claim 5, characterized in that, The chute assembly further includes a second chute unit (8), which is disposed between the first chute unit (7) and the bottom end of the cable (1). The second chute unit (8) includes a second base (8.1), a second hemisphere (8.2), a support (8.3), and a connector (8.4). The second base (8.1) is detachably mounted on the cable (1). The support (8.3) is mounted on the second base (8.1). A protrusion (8.3.1) is provided on the connecting body (8.4); the connecting body (8.4) is connected to the second hemisphere (8.2), and a groove (8.4.1) adapted to the protrusion (8.3.1) is provided on the connecting body (8.4); a second arc-shaped groove (8.2.1) for the steel wire rope (6) to slide through is provided on the second hemisphere (8.2); the central axis of the second arc-shaped groove (8.2.1) is coplanar with the straight line containing the length of the cable (1); The second arc-shaped groove (8.2.1) bends toward the cable (1), and the wire rope (6) passes through the second arc-shaped groove (8.2.1). 8.2.1) When the maximum distance between the cable (1) and the wire rope (6) is greater than the distance between the wire rope (6) and the first arc-shaped groove ( 7.2.1) is the minimum distance between the cable (1) and the cable.

7. The method for measuring the cable length of a cable-stayed bridge according to claim 6, characterized in that, The shape of the protrusion (8.3.1) includes square, triangular or trapezoidal.

8. The method for measuring the cable length of a cable-stayed bridge according to claim 6, characterized in that, Both the first base (7.1) and the second base (8.1) are detachably mounted on the cable (1) using structural adhesive.

9. The method for measuring the cable length of a cable-stayed bridge according to claim 6, characterized in that, Lubricant is applied to the first arc-shaped groove (7.2.1) and the second arc-shaped groove (8.2.1).

10. The method for measuring the cable length of a cable-stayed bridge according to claim 6, characterized in that, The diameter of the wire rope (6) is 0.1-0.2 mm.

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