A device and method for testing the torsional performance of a main cable of a spatial cable-suspension bridge

Abstract

The application discloses a kind of spatial cable suspension bridge main cable torsional performance test experimental device, including the main cable of scale reduction, cable tower and sling;Further include: end anchor, spatial form conversion device, torsion angle measuring device and sling loading device;The end anchor is anchored in the main cable in midspan position, the end anchor includes tensioning mechanism, horizontal slide rail, vertical slide rail, anchor head outer frame and rotating anchor plate, the horizontal displacement slide rail is fixed in midspan position, the vertical slide rail is slidably arranged on horizontal slide rail, the anchor head outer frame is slidably arranged on vertical slide rail, rotating anchor plate is rotatably fixed on anchor head outer frame by anchor plate shaft, the anchor head of cable strand for fixing main cable cable strand is arranged on the rotating anchor plate, the tensioning mechanism drives the rotating anchor plate clockwise / counterclockwise rotation.The application solves the problems that the traditional spatial cable test torsional stiffness cannot be measured, the trend of cable strand full-line stiffness change, the torsion condition of cable strand is difficult to measure and the like.

Description

Technical Field

[0001] This patent relates to the torsion control technology of main cable strands in suspension bridge engineering, specifically a test device and method for testing the torsion performance of the main cable of a space cable suspension bridge. Background Technology

[0002] Suspension bridges are widely used due to their large span capacity, and space cable suspension bridges are becoming increasingly advantageous due to their high lateral stiffness. However, the torsional stiffness of space cables is not only directly related to structural dimensions, but also closely related to factors such as the stress state of the main cable, spatial morphology, and wire interface. Currently, there is no complete experimental device and method to simulate and evaluate the torsion during the construction of space cable suspension bridges. Current experiments on the torsional stiffness of the main cable can only perform qualitative analyses, which makes it impossible to conduct a detailed analysis of the construction process of the space cable main cable. Therefore, there is an urgent need to propose an experimental device and method for testing the torsional performance of the main cable of a space cable suspension bridge.

[0003] For suspension bridges with planar cables and small space effects, the torsional stiffness is relatively small due to the large difference between the span effect and the size effect of the main cable. Only when there is a large temperature gradient in the main cable will a slightly larger torsion occur. Cable clamp positioning, installation and other processes are usually carried out at night when the temperature is constant, so temperature has almost no impact on the construction quality.

[0004] However, for large spatial effect suspension bridges, in order to improve the lateral stiffness, the lateral width and height of the main cable vary greatly. This requires lateral jacking after the main cable is constructed. The jacking process will generate a large torsion. Therefore, the cable clamps are pre-deflected before jacking to account for the torsion during the jacking process. The determination of the pre-deflection angle of the cable clamps is directly related to the angle between the suspenders and the main beam. Due to the lack of torsional stiffness of the main cable under specific spatial effects and stress states for spatial cable suspension bridges, it is impossible to conduct a detailed analysis of the torsion of the main cable. Summary of the Invention

[0005] To address the challenge of measuring torsional stiffness during the construction of the main cable of a space cable suspension bridge, this invention proposes an experimental device and method for testing the torsional performance of the main cable of a space cable suspension bridge.

[0006] The technical solution adopted by the present invention to solve this technical problem is: a test device for testing the torsional performance of the main cable of a spatial cable suspension bridge, including a scaled-down main cable, tower and suspenders; and also including: end anchor, spatial shape conversion device, torsion angle measuring device and suspender loading device;

[0007] The end anchor secures the main cable at the mid-span position. The end anchor includes a tensioning mechanism, a horizontal slide rail, a vertical slide rail, an anchor head frame, and a rotating anchor plate. The horizontal slide rail is fixed at the mid-span position. The vertical slide rail is slidably mounted on the horizontal slide rail. The anchor head frame is slidably mounted on the vertical slide rail. The rotating anchor plate is rotatably fixed on the anchor head frame via an anchor plate shaft. The rotating anchor plate is provided with strand anchor heads for fixing the main cable strands. The tensioning mechanism drives the rotating anchor plate to rotate clockwise / counterclockwise.

[0008] The spatial morphology conversion device is used to apply a horizontal force to the main cable, so that the main cable is converted from a planar cable to a spatial cable in terms of spatial morphology.

[0009] The torsion angle measuring device is used to measure the torsion angle of the main cable;

[0010] The sling loading device is used to adjust the deflection angle of the sling.

[0011] Preferably, the scaling ratio is 1:10 to 1:5, and the length of the experimental setup is within 30m.

[0012] Preferably, the spatial transformation device includes: a column, a first pulley, a limiting device, a second winch, and a first wire rope;

[0013] The column is fixed with a first pulley and a limiting device. The first wire rope on the second winch is converted from the vertical direction to the horizontal direction through the first pulley and then passes through the limiting device to be fixed to the main cable so as to apply a horizontal force to the main cable.

[0014] Preferably, the torsion angle measuring device includes a main cable clamp and two total stations;

[0015] The main cable clamp fixes the main cable, and elevation points are symmetrically set on opposite sides of the main cable clamp. Two total stations are used to detect the elevation changes of the two elevation points.

[0016] Preferably, the sling consists of a sling clamp and a boom, and the boom is connected to the main cable via the sling clamp;

[0017] The sling loading device includes a base, a slider, a second pulley, and a counterweight; the slider is horizontally slidable on the base, a bracket is fixed on the base, the second pulley is fixed on the bracket, the sling is fixed to the rope, and the rope passes around the slider and then turns through the second pulley to connect with the counterweight.

[0018] The present invention also provides a method for testing the torsional performance of the main cable of a space cable suspension bridge using the aforementioned experimental apparatus, characterized by comprising the following steps:

[0019] Step 1: Scale down the entire bridge to a certain scale and process the main cable, towers, suspenders, end anchors, spatial shape conversion device, torsion angle measuring device and suspender loading device according to the corresponding dimensions;

[0020] Step 2: After erecting the parallel main cable, anchor both ends of the cable strands, connecting the strands to the end anchors at the mid-span end. Install the spatial shape conversion device, torsion angle measuring device, and sling loading device. Then, use the spatial shape conversion device for jacking construction to convert the main cable to the spatial alignment. After adjusting to the specified tension angle using the sling loading device, tension the cable according to the design tension. Use the total station of the torsion angle measuring device to read the coordinates of two elevation points (x1') on the main cable clamp. ， y1' ， z1'), (x2') ， y2' ， z2');

[0021] Step 3: Tension the tensioning mechanism on the tensioning end anchor so that the cable strand anchor head rotates around the outer frame of the anchor head. Record the tension T and lever arm L of the tensioning mechanism at this time, and then obtain the torque M = T * L.

[0022] Step 4: Use a total station with a torsion angle measuring device to read the torsion angle and the coordinates (x, y) of two elevation points on the main cable clamp. 1， y 1， z1), (x 2， y 2， z2), the twist angle of the cable strand is calculated using the following formula:

[0023]

[0024] Step 5: Calculate the torsional stiffness of the main cable based on the torque and torsion angle.

[0025] The present invention has at least the following beneficial effects:

[0026] The experimental apparatus and method for testing the torsional performance of the main cable of a suspension bridge using a space cable can serve as an important means of analyzing the mechanical behavior of the space cable during construction. This apparatus is not only simple and reasonable in structure and convenient to install and apply, but it also solves the problems of traditional space cable experiments, such as the inability to measure torsional stiffness, the trend of stiffness variation along the entire cable strand, and the difficulty in measuring the torsion of the cable strands.

[0027] It has the following characteristics:

[0028] (1) It can simulate the main cable jacking construction process of a space cable suspension bridge and quantify the torque value during the main cable torsion process;

[0029] (2) It can accurately simulate the torsional characteristics and torsional stiffness of the main cable under different stress states;

[0030] (3) It can measure the torsional stiffness of key parts of the cable strand under different jacking strokes, which is more reliable than the previous linear interpolation method.

[0031] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the experimental device for testing the torsional performance of the main cable of a space cable suspension bridge according to the present invention.

[0033] Figure 2 This is a schematic diagram of the spatial form transformation device of the present invention;

[0034] Figure 3 This is a schematic diagram of the sling loading device of the present invention;

[0035] Figure 4 This is a schematic diagram of the torsion angle measuring device of the present invention;

[0036] Figure 5 This is a schematic diagram of the end anchor structure of the present invention;

[0037] Figure 6 This is a partial enlarged view of the end anchor of the present invention.

[0038] Explanation of reference numerals in the attached drawings: 1 Main cable, 2 Tower, 3 Suspension cable, 31 Cable clamp, 32 Suspension rod, 4 End anchor, 41 First winch, 42 Horizontal slide rail, 43 Vertical slide rail, 44 Anchor head frame, 45 Rotating anchor plate, 46 Cable strand anchor head, 47 Anchor plate shaft, 5 Spatial shape conversion device, 51 Column, 52 First pulley, 53 Limiting device, 54 Second winch, 55 First wire rope, 6 Suspension cable loading device, 61 Base, 62 Slider, 63 Second pulley, 64 Counterweight, 65 Support, 66 Rope, 71 Main cable clamp, 72 Total station. Detailed Implementation

[0039] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in various parts of the present invention, including the following description, can be combined with each other without conflict.

[0040] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific implementation process is as follows:

[0042] like Figures 1-6 As shown, the present invention provides an experimental device for testing the torsional performance of the main cable of a spatial cable suspension bridge, including a scaled-down main cable 1, a tower 2, and a suspension cable 3; it also includes: an end anchor 4, a spatial shape conversion device 5, a torsion angle measuring device, and a suspension cable loading device 66;

[0043] The end anchor 4 anchors the main cable 1 at the mid-span position. The end anchor 4 includes a tensioning mechanism (which can be a first winch 41 / hand-operated hoist, but is not limited to these two devices), a horizontal slide rail 42, a vertical slide rail 43, an anchor head frame 44, and a rotating anchor plate 45. The horizontal slide rail is fixed at the mid-span position, the vertical slide rail 43 is slidably mounted on the horizontal slide rail 42, and the anchor head frame 44 is slidably mounted on the vertical slide rail 43. The vertical slide rail 43 and the anchor head frame 44 can be fixed and limited after sliding to the target position, and can rotate... Anchor plate 45 is rotatably fixed to anchor head frame 44 via anchor plate shaft 47. A strand anchor head 46 is provided on the rotating anchor plate 45 for fixing the strands of main cable 1. The strand anchor head 46 is connected to the rotating anchor plate 45 by bolts. The tensioning mechanism drives the rotating anchor plate 45 to rotate clockwise / counterclockwise. The spatial shape transformation of main cable 1 at this position is realized by horizontal slide rail 42 and vertical slide rail 43. After the main cable 1 is twisted, the torque is measured by the first winch 41 or hand chain hoist at the tangent position on the outside of the rotating plate.

[0044] The spatial shape conversion device 5 is used to apply a horizontal force to the main cable 1, so that the main cable 1 is converted from a planar cable to a spatial cable in terms of spatial shape, and the main cable 1 is fixed in linear shape.

[0045] The torsion angle measuring device is used to measure the torsion angle of the main cable 1;

[0046] The sling loading device 66 is used to adjust the deflection angle of the sling 3.

[0047] In the above technical solution, in order to simulate the torsional stiffness change of the main cable 1 under different torsional states at different construction stages, and at the same time to minimize materials and labor, only a small part of the side span is anchored. Since the torsion is minimal in the middle of the main span, the anchoring point is set in the middle of the main span according to the principle of symmetry. The experimental device for testing the torsional performance of the main cable 1 of the spatial cable suspension bridge mainly includes the main cable 1 and the tower 2 of a small part of the side span and half of the main span. The experiment adopts a scaled-down design, which can be adjusted according to the timing. The scaled-down ratio should be between 1:10 and 1:5, and the experimental length should be within 30m.

[0048] This technical solution may also include the following technical details to better achieve the technical effect: the scaling ratio is 1:10 to 1:5, and the length of the experimental device is within 30m.

[0049] This technical solution may also include the following technical details to better achieve the technical effect: The spatial form conversion device 5 includes: a column 51, a first pulley 52, a limiting device 53, a second winch 54, and a first wire rope 55;

[0050] A first pulley 52 and a limiting device 53 are fixed on the column 51. The first wire rope 55 on the second winch 54 is converted from a vertical direction to a horizontal direction through the first pulley 52 and then passes through the limiting device 53 to be fixed to the main cable 1, so as to apply a horizontal force to the main cable 1. By setting pulleys on the column 51 and setting winches and other devices at the bottom of the column 51, the horizontal support of the main cable 1 is simulated, realizing the spatial transformation of the main cable 1 from a planar cable to a spatial cable.

[0051] This technical solution may also include the following technical details to better achieve the technical effect: the torsion angle measuring device includes a main cable clamp 1 and two total stations 72;

[0052] The main cable 1 clamp fixes the main cable 1. Elevation points are symmetrically arranged on opposite sides of the main cable 1 clamp. Two total stations 72 are used to detect the elevation changes of the two elevation points.

[0053] This technical solution may also include the following technical details to better achieve the technical effect: the sling 3 is composed of a sling clamp 31 and a sling rod 32, and the sling rod 32 is connected to the main cable 1 through the sling clamp 31;

[0054] The cable loading device 66 includes a base 61, a slider 62, a second pulley 63, and a counterweight 64. The slider 62 is horizontally slidable on the base 61. A bracket 65 is fixed on the base 61, and the second pulley 63 is fixed on the bracket 65. The suspension rod 32 is fixed to the rope 66. The rope 66 passes around the slider 62 and then turns through the second pulley 63 to connect with the counterweight 64. A combination of pulley and weight is used to simulate the force of the cable 3. The deflection angle of the cable 3 of the spatial cable suspension bridge is adjusted by sliding the position of the slider 62, thus fixing the shape and angle of the cable 3. Preferably, the slider 62 is circular with an indented groove on its outer circumference for the second wire rope to pass through. The counterweight 64 can be made of different numbers of weights.

[0055] The present invention also provides a method for testing the torsional performance of the main cable of a space cable suspension bridge using the aforementioned experimental apparatus, characterized by comprising the following steps:

[0056] Step 1: Scale down the entire bridge according to a certain scale. In order to save costs, mainly simulate the deformation of half of the middle span. Process the main cable 1, tower 2, suspension cable 3, end anchor 4, spatial shape conversion device 5, torsion angle measuring device and suspension cable loading device 66 according to the corresponding dimensions.

[0057] Step 2: After erecting the parallel main cable, anchor both ends of the cable strand. Connect the cable strand to the end anchor 4 at the mid-span end and install appropriate counterweights 64. Install the spatial shape conversion device 5, torsion angle measuring device, and sling loading device 66. Then, use the spatial shape conversion device 5 to perform jacking construction, converting the main cable to the spatial alignment. After adjusting to the specified tension angle using the sling loading device 66, tension the cable according to the design tension. Use the total station 72 of the torsion angle measuring device to read the coordinates (x1') of two elevation points on the main cable clamp. ， y1' ， z1'), (x2') ， y2' ， z2');

[0058] Step 3: Tensioning mechanism on the tensioning end anchor 4. In this embodiment, the tensioning mechanism is the first winch 41, which makes the cable strand anchor head 46 rotate around the anchor head outer frame 44. Record the tension T and lever arm L of the tensioning mechanism at this time, and then obtain the torque M = T * L.

[0059] Step 4: Use a total station 72 with a torsion angle measuring device to read the torsion angle and the coordinates (x, y) of two elevation points on the main cable clamp 1. 1， y 1， z1), (x 2， y 2， z2), the twist angle of the cable strand is calculated using the following formula:

[0060]

[0061] Step 5: Calculate the torsional stiffness of main cable 1 based on torque and torsion angle.

[0062] In the above technical solution, since the tension and spatial state of the cable strands are not completely consistent, in order to meet the requirements of high-precision calculation, it is necessary to accurately measure the torsional stiffness of each part. The general idea is to measure two physical quantities (torsion angle and torsional force), tension the main cable 1 in batches and load the suspension cable 3, so as to analyze the torsional stiffness changes under multiple working conditions at each stage of the construction of the superstructure.

[0063] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. An experimental device for testing the torsional performance of the main cable of a space cable suspension bridge, characterized in that, Includes scaled-down main cable, tower, and suspenders; also includes: end anchors, spatial shape conversion device, torsion angle measuring device, and suspender loading device; The end anchor secures the main cable at the mid-span position. The end anchor includes a tensioning mechanism, a horizontal slide rail, a vertical slide rail, an anchor head frame, and a rotating anchor plate. The horizontal slide rail is fixed at the mid-span position. The vertical slide rail is slidably mounted on the horizontal slide rail. The anchor head frame is slidably mounted on the vertical slide rail. The rotating anchor plate is rotatably fixed to the anchor head frame via an anchor plate shaft. The rotating anchor plate is provided with strand anchor heads for fixing the main cable strands. The tensioning mechanism drives the rotating anchor plate to rotate clockwise / counterclockwise. The spatial morphology conversion device is used to apply a horizontal force to the main cable, so that the main cable is converted from a planar cable to a spatial cable in terms of spatial morphology. The torsion angle measuring device is used to measure the torsion angle of the main cable; The sling loading device is used to adjust the deflection angle of the sling.

2. The experimental apparatus for testing the torsional performance of the main cable of a space cable suspension bridge as described in claim 1, characterized in that, The scaling ratio is 1:10 to 1:5, and the length of the experimental setup is within 30m.

3. The experimental apparatus for testing the torsional performance of the main cable of a space cable suspension bridge as described in claim 1, characterized in that, The spatial transformation device includes: a column, a first pulley, a limiting device, a second winch, and a first wire rope; The column is fixed with a first pulley and a limiting device. The first wire rope on the second winch is converted from the vertical direction to the horizontal direction through the first pulley and then passes through the limiting device to be fixed to the main cable so as to apply a horizontal force to the main cable.

4. The experimental apparatus for testing the torsional performance of the main cable of a space cable suspension bridge as described in claim 1, characterized in that, The torsion angle measuring device includes a main cable clamp and two total stations; The main cable clamp fixes the main cable, and elevation points are symmetrically set on opposite sides of the main cable clamp. Two total stations are used to detect the elevation changes of the two elevation points.

5. The experimental apparatus for testing the torsional performance of the main cable of a space cable suspension bridge as described in claim 1, characterized in that, The sling consists of a clamp and a boom, and the boom is connected to the main cable via the clamp. The sling loading device includes a base, a slider, a second pulley, and a counterweight; The slider is horizontally slidable on the base, a bracket is fixed on the base, a second pulley is fixed on the bracket, the rod is fixed to the rope, and the rope passes around the slider and then turns through the second pulley to connect with the counterweight.

6. A method for testing the torsional performance of the main cable of a space cable suspension bridge using the experimental apparatus described in claim 4, characterized in that, Includes the following steps: Step 1: Scale down the entire bridge to a certain scale and process the main cable, towers, suspenders, end anchors, spatial shape conversion device, torsion angle measuring device and suspender loading device according to the corresponding dimensions; Step 2: After erecting the parallel main cable, anchor both ends of the cable strand, and connect the cable strand to the end anchor at the mid-span end position; After installing the spatial shape conversion device, torsion angle measuring device, and cable loading device, the main cable was jacked using the spatial shape conversion device to convert it to the spatial alignment. The cable loading device was then used to adjust the cable to the specified tension angle before tensioning at the design tension. The total station of the torsion angle measuring device was used to read the coordinates of two elevation points (x1, x2, x3) on the main cable clamp. ’ ， y1 ’ ， z1 ’ (x2) ’ ， y2 ’ ， z2 ’ ); Step 3: Tension the tensioning mechanism on the tensioning end anchor so that the cable strand anchor head rotates around the outer frame of the anchor head. Record the tension T and lever arm L of the tensioning mechanism at this time, and then obtain the torque M=T*L; Step 4: Use a total station with a torsion angle measuring device to read the torsion angle and the coordinates of two elevation points (x, y, y) on the main cable clamp. 1， y 1， z1), (x 2， y 2， z2), the twist angle of the cable strand is calculated using the following formula: Step 5: Calculate the torsional stiffness of the main cable based on the torque and torsion angle.

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