Suspension Bridge Long Hanger Unloading Device and Method

Abstract

The present invention discloses a long suspension cable unloading device for a suspension bridge, which includes a through-type jack, a through-type shoulder beam, a cable gripper, a steel strand, and a bottom anchoring device; the through-type shoulder beam includes two main bodies, and the main bodies are provided with semicircular grooves; the bottom anchoring device is fixed to the top plate of the steel box beam, one end of the steel strand is fixed to the bottom anchoring device, and the other end is fixed to the through-type jack, and the through-type jack controls the steel strand, so that the portion of the sling along the cable gripper downward becomes a stress-free section and the unloading is completed, so that the condition that the bottom anchor of the sling can be removed is achieved, and after the bottom anchor of the sling is removed, the jack is used to unload the full length of the sling to finally achieve unloading. The technical problem that conventional sling tensioning cannot be used to shorten the beam-cable spacing to unload old slings with a long length is solved, and the structure is reasonable, the force transmission path is clear, the force is safe and reliable, and the scope of application is wide. The present invention also discloses a long suspension cable unloading method for a suspension bridge.

Description

Technical Field

[0001] The present invention relates to the field of suspension bridges, and particularly to a long hanger unloading device and method for a suspension bridge. Background Art

[0002] At present, suspension bridges have the strongest spanning ability among all bridge types. When the bridge span exceeds 800m, suspension bridges are the preferred bridge type. The vast majority of extra-large bridges with a main span exceeding one kilometer are of the suspension bridge type. Suspension bridges are favored by builders due to their super strong spanning ability. Since the completion and opening to traffic of the Humen Bridge, the first modern suspension bridge independently designed and built in China in 1997, many extra-large-span suspension bridges such as the Xiling Yangtze River Bridge, Jiangsu Jiangyin Yangtze River Bridge, Aizhai Bridge, Xihoumen Bridge, and Nansha Bridge have been successively built in China. Among the top ten suspension bridges in the world, 6 are in China. At the same time, China has become the country with the largest number of suspension bridges in the world. The suspension system of a suspension bridge consists of main cables, cable clamps, and hangers. The cable clamps are installed on the main cables. The top of the hanger is connected to the cable clamp, and the bottom of the hanger is connected to the main beam, thereby forming a suspension support for the main beam of the suspension bridge. Suspension bridge hangers are divided into straddle-type hangers and top-pin-connected hangers according to different connection methods with the cable clamp, and are divided into anchored hangers and pin-connected hangers according to different connection methods with the main beam. The main beams of suspension bridges mainly have three types: prestressed reinforced concrete main beams, steel box girders, and steel truss girders. Steel box girder main beams and steel truss girder main beams are widely used at home and abroad. The large-span suspension bridges built in the early days in China basically mainly used straddle-type hangers. Since the hanger material technology was not yet developed in the last century, and at the same time due to the long-term overloading of domestic vehicles, the hangers of suspension bridges with a service life of more than 20 years in China have begun to show various problems such as hanger aging and damage. Replacing the hangers is the best way to solve this problem.

[0003] The replacement of suspension bridge hangers will increasingly become an urgent need over time. However, the domestic industry is still in the exploration stage in the field of suspension bridge hanger replacement construction. At present, only a few suspension bridges such as the Shantou Bay Bridge, Jiangsu Jiangyin Bridge, and Humen Bridge have replaced individual short hangers, and there is no experience in replacing all the hangers of extra-large suspension bridges and replacing long hangers in China.

[0004] Before replacing the suspension bridge hanger, it is necessary to first unload the old hanger to be replaced so that the old hanger is no longer stressed at the anchorage, and then it can be removed. The domestic and international industries mainly use the method of setting tensionable temporary hangers for the replacement of suspension bridge hangers. First, tensionable temporary hangers are set at the location of the hanger to be replaced. The top of the temporary hanger straddles the permanent cable clamp or the temporary cable clamp, and the bottom is anchored to the main beam. By tensioning the temporary hanger to shorten its length, and then shortening the beam-cable spacing at the location of the old hanger to be replaced, the old hanger is "relaxed" and unloaded.

[0005] For short and relatively short slings, the elongation value of the sling under stress is small, and the method of unloading by shortening the beam-cable spacing is applicable; however, for long slings exceeding a certain length, the elongation value under stress is large, and the relaxation deformation value produced after long-term continuous loading is also large, and the beam-cable spacing shortening value produced by tensioning temporary slings is limited and restricted. The smaller beam-cable spacing shortening value produced by tensioning temporary slings cannot offset the existing larger deformation value of the long slings, that is, the long slings cannot be unloaded in this way.

[0006] In addition, the length of the temporary sling at each cable replacement point corresponds to the length of the corresponding sling. The longer the sling to be replaced, the longer the length of the temporary sling, and the more difficult it is to install the temporary sling. At the same time, the length of the sling corresponds to the tangent angle of the main cable at the corresponding point. The closer to the cable tower, the larger the tangent angle of the main cable and the longer the sling length, that is, the longer the sling corresponds to the larger tangent angle at the main cable, and the larger the tangent angle of the main cable, the greater the friction between the permanent cable clamp or the temporary cable clamp and the main cable along the tangent direction of the main cable due to the temporary sling load, which is more unfavorable to the force safety of the permanent cable clamp or the temporary cable clamp.

[0007] In summary, the replacement of long slings is a technical difficulty in the replacement of suspension bridge slings, which is recognized by the industry at home and abroad. Unloading the long slings before replacement is another difficulty in the replacement of long slings. At present, there is no mature technology for unloading long slings of super-large suspension bridges at home and abroad. Summary of the invention

[0008] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a long sling unloading device and method for a suspension bridge, which can solve the problem of difficulty in replacing the sling.

[0009] One of the purposes of the present invention is achieved by the following technical solution:

[0010] A long-cable unloading device for a suspension bridge is applied to a suspension bridge. The suspension bridge comprises a steel box girder top plate, a cable steel sleeve, a cable clamp, a main cable and cables respectively connected to the beam top plate and the main cable. The long-cable unloading device for the suspension bridge comprises a through-type jack, a through-type shoulder-pole beam, a cable gripper, a steel strand and a bottom anchoring device. The through-type shoulder-pole beam comprises two main bodies, each of which is provided with a semicircular groove, and the cable is located in the semicircular groove and fixed by the two main bodies. The cable gripper is wrapped and fixed on the cable, the through-type jack is installed on the through-type shoulder-pole beam, the bottom anchoring device is fixed to the steel box girder top plate, one end of the steel strand is fixed to the bottom anchoring device, and the other end is fixed to the through-type jack. Through the control of the steel strand by the through-type jack, the portion of the cable along the cable gripper downward becomes a stress-free section and the unloading is completed.

[0011] Further, two of the through-type spreader beams are correspondingly provided for each of the through-type jacks. The sling is located in the middle of the through-type spreader beam, and the two through-type jacks are distributed on both sides of the sling.

[0012] Further, the through-type spreader beam is further provided with two semi-long grooves and a plurality of bolt holes. The semi-circular groove is located between the two semi-long grooves, and the bolt holes are evenly distributed at both ends of the through-type spreader beam.

[0013] Further, the through-type spreader beam further includes high-strength bolts, and the high-strength bolts pass through the bolt holes to fix the two bodies and the sling.

[0014] Further, the long sling unloading device for the suspension bridge further includes a plurality of single-hole anchors. The end of the steel strand is clamped and abutted against the single-hole anchor, and the single-hole anchor is arranged on the through-type jack and the bottom anchoring device.

[0015] Further, the long sling unloading device for the suspension bridge further includes an anti-torsion device. The anti-torsion device includes two wedge-shaped pads, a movable anchor plate and a fixed anchor plate, and the two wedge-shaped pads are fixed on the movable anchor plate and the fixed anchor plate.

[0016] Further, the movable anchor plate and the fixed anchor plate are distributed at both ends of the wedge-shaped pad, and the wedge-shaped pad is perpendicular to the movable anchor plate.

[0017] Further, the two movable anchor plates are arranged in parallel, the sling passes between the two movable anchor plates, and the two wedge-shaped pads are arranged in parallel; the sling gripper includes two clamping blocks, two sling gripping blocks and a long pin rod, and one ends of the two sling gripping blocks are hinged and the other ends are fixed by the long pin rod.

[0018] Further, the fixed anchor plate is provided with a round hole and a screw, the steel strand passes through the round hole, and the screw fixes the bottom anchoring device on the top plate of the steel box girder.

[0019] Further, the long sling unloading device for the suspension bridge further includes an anti-slip pad, and the anti-slip pad is fixed on the movable anchor plate and abuts against the end of the wedge-shaped pad.

[0020] A method for unloading the long sling of a suspension bridge, which is applied to the long sling unloading device of a suspension bridge. The suspension bridge includes a top plate of a steel box girder, a sling steel sleeve, a cable clamp, a main cable and a sling respectively connected to the top plate of the steel box girder and the main cable. The long sling unloading device of the suspension bridge includes a through-type jack, a through-type spreader beam, a sling gripper, a steel strand, a bottom anchoring device and an anti-torsion device, and includes the following steps:

[0021] Steps for sling locking: Fix the cable gripper to the sling, and the through-type spreader beam fixes the sling;

[0022] Pre-tightening steps: Install the through-type jack on the through-type spreader beam, pass one end of the steel strand through the through-type jack, connect the other end to the bottom anchoring device, and fix the bottom anchoring device on the bottom surface of the steel box girder top plate;

[0023] Anti-twist steps: Install the anti-twisting device on the cable gripper;

[0024] Unloading steps: The through-type jack operates to completely unload the sling along the cable gripper to the bottom;

[0025] Demolition steps: Demolish the anchoring structure of the sling.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The through-type spreader beam includes two bodies, each body is provided with a semi-circular groove, the sling is located in the semi-circular groove and is fixed by the two bodies; the cable gripper is covered and fixed on the sling, the through-type jack is installed on the through-type spreader beam, the bottom anchoring device is fixed on the steel box girder top plate, one end of the steel strand is fixed to the bottom anchoring device, and the other end is fixed to the through-type jack. By controlling the steel strand through the through-type jack, the part of the sling along the cable gripper downward becomes a stress-free section and is unloaded. It solves the technical problem that it is impossible to use the conventional sling tensioning to shorten the beam-cable spacing to unload the long old sling. The structure is reasonable, the force transmission path is clear, the force is safe and reliable, and the application range is wide. The application is not limited by the sling length and the connection relationship with the cable clip, nor by the form of the main beam of the suspension bridge. It can not only be effectively applied to the unloading of long slings of suspension bridges, but also be fully applicable to the unloading of slings of various lengths such as short slings; it can not only be adapted to the pin-connected slings with cable clips, but also be applicable to the straddle-type slings with cable clips; it is not only applicable to the steel box girder main beam, but also applicable to the steel truss girder main beam.

[0028] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given and described in detail in conjunction with the drawings as follows. Brief Description of the Drawings

[0029] Figure 1 It is the front structure diagram of the present invention;

[0030] Figure 2 It is the side structure diagram of the present invention;

[0031] Figure 3Stereogram of a sling gripper in the state of not gripping the sling in the present invention;

[0032] Figure 4 Stereogram of a sling gripper in the state of gripping the sling in the present invention;

[0033] Figure 5 Stereogram of a through-type lifting beam in the present invention;

[0034] Figure 6 Stereogram of a through-type lifting beam in the working state in the present invention;

[0035] Figure 7 Stereogram of a bottom anchoring device in the present invention;

[0036] Figure 8 It is Figure 7 Another stereogram of the bottom anchoring device shown;

[0037] Figure 9 It is Figure 7 Stereo assembly drawing of the working state of the bottom anchoring device shown;

[0038] Figure 10 It is Figure 7 Stereo assembly drawing of the working state of the bottom anchoring device shown from another angle;

[0039] Figure 11 Stereogram of an anti-torsion device in the present invention.

[0040] In the figure: 1. Through-type jack; 2. Through-type lifting beam; 201. Semi-circular groove; 202. Semi-long groove; 203. Bolt hole; 204. High-strength bolt; 3. Sling gripper; 301. Clamping block; 302. Sling gripping block; 303. Long pin rod; 4. Steel strand; 5. Bottom anchoring device; 501. Wedge-shaped cushion block; 502. Movable anchor backing plate; 503. Fixed anchor backing plate; 504. Round hole; 505. Screw; 6. Single-hole anchor; 7. Anti-slip cushion block; 8. Anti-torsion device; 801. Clamping beam; 802. Anchor backing plate; 803. Screw rod; 804. Nut; 9. Sling; 10. Steel box girder top plate; 11. Sling steel sleeve; 12. Sling clip; 13. Main cable. Detailed implementation manners

[0041] Next, in combination with the accompanying drawings and specific implementation manners, the present invention will be further described. It should be noted that on the premise of no conflict, any combination of the following-described embodiments or technical features can form a new embodiment.

[0042] It should be noted that when a component is referred to as "fixed to" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are only for the purpose of illustration.

[0043] Unless otherwise defined, all technical and scientific terms used in this article have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the description of the present invention in this article are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this article includes any and all combinations of one or more of the related listed items.

[0044] Please refer to Figures 1-11 , a long sling unloading device for a suspension bridge, which is applied to a suspension bridge. The suspension bridge includes a steel box girder top plate 10, a sling steel sleeve 11, a cable clamp 12, a main cable 13 and a sling 9 respectively connected to the steel box girder top plate 10 and the main cable 13. The long sling unloading device for a suspension bridge includes a through-hole jack 1, a through-hole balance beam 2, a wire grip 3, a steel strand 4, and a bottom anchoring device 5; the through-hole balance beam 2 includes two bodies, and each body is provided with a semi-circular groove 201, and the sling 9 is located in the semi-circular groove 201 and is fixed by the two bodies; the wire grip 3 is wrapped and fixed on the sling 9, the through-hole jack 1 is installed on the through-hole balance beam 2, the bottom anchoring device 5 is fixed to the steel box, one end of the steel strand 4 is fixed to the bottom anchoring device 5, and the other end is fixed to the through-hole jack 1. By controlling the steel strand 4 through the through-hole jack 1, the part of the sling 9 extending downward along the wire grip 3 becomes a stress-free section and the unloading is completed. It solves the technical problem that it is impossible to use the conventional sling tensioning to shorten the beam-cable spacing to unload the old sling with a large length. The structure is reasonable, the force transmission path is clear, the force is safe and reliable, and the application range is wide. The application is not limited by the sling length and the connection relationship with the cable clamp, nor by the form of the main beam of the suspension bridge. It can not only be effectively applied to the unloading of long slings of suspension bridges, but also be completely applicable to the unloading of slings of various lengths such as short slings; it can not only be adapted to the sling pinned to the cable clamp, but also to the sling straddling the cable clamp; it is not only applicable to the steel box girder main beam, but also to the steel truss girder main beam.

[0045] Using the long sling unloading device provided by the present invention to unload the old sling of the suspension bridge can save the investment of the temporary sling in the conventional temporary sling unloading method, and at the same time can greatly improve the construction efficiency and safety, and the economic benefits are also remarkable.

[0046] In specific applications, the through-type jack 1 selects a small-diameter single-bundle jack according to the actual situation of the target cable-changing bridge, and its rated tensile force and stroke size are determined according to needs. Each through-type lifting beam 2 consists of two left and right half-blocks, which are connected into a whole by high-strength bolts 204, and each half through-type lifting beam is processed from steel. A semi-circular groove 201 is provided in the middle of each half through-type lifting beam, and the radius of the semi-circular groove 201 is determined by the radius or diameter of the sling 9, and the radius of the semi-circular groove 201 must be greater than the radius of the sling 9; semi-long grooves 202 are provided in both side regions of each half through-type lifting beam, and the position and size of the semi-long grooves 202 are determined by the diameter and relative position of the steel strand 4, and the depth of the semi-long grooves 202 must be greater than the radius of the steel strand 4; a number of bolt holes 203 are symmetrically provided in the end regions of each half through-type lifting beam for inserting high-strength bolts 204 for connection, and the diameter of the bolt holes 203 needs to be matched with the high-strength bolts 204. Each cable gripper 3 consists of 2 clamping blocks 301 and 2 cable gripping blocks 302, and the two clamping blocks are connected by 2 long pin rods 303. The clamping blocks 301 and the cable gripping blocks 302 are both processed from a whole piece of steel and shall not be welded. A semi-circular groove is provided in the cable gripping block 302, and a circular hole structure is formed in the middle after the two cable gripping blocks 302 are closed, and the diameter of the circular hole must be slightly smaller than the diameter of the sling 9 to generate sufficient gripping force on the sling. Each set of bottom anchoring device 5 consists of 2 wedge-shaped pads 501, 1 movable anchor plate 502, 1 fixed anchor plate 503, 4 screws 505, etc. The wedge-shaped pads 501 are processed from thick steel plates, and 2 screw holes are drilled at the bottom of each wedge-shaped pad 501. The fixed anchor plate 503 is processed from a steel plate, with a circular hole 504 drilled in the middle, and the diameter of the circular hole 504 should be greater than the diameter of the steel strand 4, and 1 screw hole is drilled on each side. The movable anchor plate 502 is processed from a steel plate, with a circular hole 504 drilled in the middle, and the diameter of the circular hole 504 should be greater than the diameter of the steel strand 4, and 1 screw hole is drilled on each side.

[0047] The single-hole anchor 6 is selected according to the principle of matching the specifications of the steel strand 4. The anti-slip pad 7 is processed from steel, and its size is determined according to the actual situation. The anti-torsion device 8 consists of 2 clamping beams 801, 8 anchor plates 802, 4 screw rods 803 and supporting nuts 804, etc. The clamping beams 801 are processed from back-to-back channel steels, and the distance between the back-to-back channel steels should be greater than the diameter of the screw rod 803. The anchor plates 802 are processed from steel plates, with circular holes drilled in the middle, and the diameter of the circular holes is slightly larger than the diameter of the screw rod 803.

[0048] Preferably, two of the through-type jacks 1 are correspondingly arranged for each through-type lifting beam 2, the sling 9 is located in the middle of the through-type lifting beam 2, and the two through-type jacks 1 are distributed on both sides of the sling 9. The smoothness at both ends of the sling 9 is improved, and smooth unloading is ensured.

[0049] Preferably, the through-type lifting beam 2 is further provided with two semi-long grooves 202 and a plurality of bolt holes 203. The semi-circular groove 201 is located between the two semi-long grooves 202, and the bolt holes 203 are evenly distributed at both ends of the through-type lifting beam 2. The structural stability is good, and deviation is avoided during the demolition process.

[0050] In specific applications, the sling gripper 3 is installed at a height of approximately 1.5 m to 2.0 m at the bottom of two slings 9. The installation heights of the two sling grippers 3 are kept consistent. The sling gripping block 302 of the sling gripper 3 is located at the lower part and grips the sling 9. Each through-type lifting beam 2 is installed and supported on two sling grippers 3. The round hole in the middle of the through-type lifting beam 2 encloses the sling 9. Each through-type lifting beam 2 consists of two left and right half-blocks, and the two half-blocks are connected into a whole through high-strength bolts 204. A semi-circular groove 201 is provided in the middle of each semi-through-type lifting beam. The radius of the semi-circular groove 201 is determined by the radius or diameter of the sling 9, and the radius of the semi-circular groove 201 must be greater than the radius of the sling 9. Semi-long grooves 202 are provided in both side areas of each semi-through-type lifting beam. The position and size of the semi-long grooves 202 are determined by the diameter and relative position of the steel strand 4, and the depth of the semi-long grooves 202 must be greater than the radius of the steel strand 4. A number of bolt holes 203 are symmetrically provided in the end areas of each semi-through-type lifting beam for passing through high-strength bolts 204 for connection. The diameter of the bolt holes 203 needs to be matched with that of the high-strength bolts 204. The through-type jack 1 is installed and supported at both ends of the through-type lifting beam 2, and one through-type jack 1 is arranged above each end of each through-type lifting beam 2. The installation position of the through-type jack 1 on the through-type lifting beam 2 is located in the middle of the long groove. The bottom anchoring device 5 is installed on the bottom surface of the steel box girder top plate 10, and the middle notch of the bottom anchoring device 5 passes through the sling 9. Each set of bottom anchoring device 5 consists of 2 wedge-shaped pads 501, 1 movable anchor plate 502, 1 fixed anchor plate 503, 4 screws 505, etc. The angle at the top of the wedge-shaped pad is consistent with its supporting surface such as the bottom surface of the steel box girder top plate. The two wedge-shaped pads 501 are arranged in parallel, and the side-to-side spacing is determined by the diameter of the sling 9, and this spacing must be greater than the diameter of the sling 9. Two screw holes are drilled at the bottom of each wedge-shaped pad 501 for fixing with the anchor plate. The fixed anchor plate 503 and the movable anchor plate 502 are arranged at the bottom of the two wedge-shaped pads 501. The fixed anchor plate 503 is fixed to the wedge-shaped pad 501 through the screws 505 between the wedge-shaped pads. The movable anchor plate 502 can be fixed to the wedge-shaped pad 501 through the screws 505 or may not be fixed. One round hole 504 is drilled in the middle of the fixed anchor plate 503, and the diameter of the round hole 504 should be greater than the diameter of the steel strand 4, and one screw hole is drilled on each side. One round hole 504 is drilled in the middle of the movable anchor plate 502, and the diameter of the round hole 504 should be greater than the diameter of the steel strand 4, and one screw hole is drilled on each side. The steel strand 4 is installed by passing through the through-type jack 1, the through-type lifting beam 2, the sling steel sleeve 11, and the bottom anchoring device 5 from top to bottom. A single-hole anchor 6 is provided at each end of each steel strand 4. The single-hole anchor 6 at the top is supported on the top surface of the through-type jack 1, and the single-hole anchor at the bottom is supported on the bottom surfaces of the fixed anchor plate 503 and the movable anchor plate 502 of the bottom anchoring device 5.The anti-slip spacer block 7 is installed on the high side of the bottom anchoring device 5, supported on the top surface of the movable anchor backing plate 502, and forms a support between the bottom anchoring device 5 and the inner side plate of the steel box girder. The anti-torsion device 8 is installed on the sides of the two cable grippers 3. Two clamping beams 801 are tightly locked above the cable grippers 3 through the screw 803, thereby connecting the two cable grippers 3 into a whole, restricting the torsion of each other, and further achieving the purpose of restricting the torsion of the sling 9. Each set of anti-torsion device 8 consists of 2 clamping beams 801, 8 anchor backing plates 802, 4 screws 803 and matching nuts 804, etc. The clamping beam 801 is made of back-to-back channel steel, and the distance between the back-to-back channel steels should be greater than the diameter of the screw 803. A round hole is drilled in the middle of the anchor backing plate 802, and the diameter of the round hole is slightly larger than the diameter of the screw 803.

[0051] Preferably, the through-type lifting beam 2 further includes high-strength bolts 204. The high-strength bolts 204 pass through the bolt holes 203 to fix the two bodies to the sling 9, improving the installation strength.

[0052] Preferably, the long sling unloading device of the suspension bridge further includes a plurality of single-hole anchors 6. The end of the steel strand 4 is clamped and abutted against the single-hole anchor 6. The single-hole anchor 6 is arranged on the through-type jack 1 and the bottom anchoring device 5, which is simple to disassemble and assemble, has strong applicability, avoids difficult disassembly and assembly, and has high efficiency.

[0053] Preferably, the long sling unloading device of the suspension bridge further includes an anti-torsion device 8. The anti-torsion device 8 includes two wedge-shaped spacer blocks 501, a movable anchor backing plate 502, and a fixed anchor backing plate 503. The two wedge-shaped spacer blocks 501 are fixed on the movable anchor backing plate 502 and the fixed anchor backing plate 503 to avoid deviation during the disassembly and assembly process.

[0054] Preferably, the movable anchor backing plate 502 and the fixed anchor backing plate 503 are distributed at both ends of the wedge-shaped spacer block 501, and the wedge-shaped spacer block 501 is perpendicular to the movable anchor backing plate 502. Specifically, the movable anchor backing plate 502 and the fixed anchor backing plate 503 are arranged in parallel, the sling 9 passes through between the two movable anchor backing plates 502, and the two wedge-shaped spacer blocks 501 are arranged in parallel; the cable gripper 3 includes two clamping blocks 301, two cable gripping blocks 302, and a long pin rod 303. One end of the two cable gripping blocks 302 is hinged, and the other end is fixed by the long pin rod 303. The fixed anchor backing plate 503 is provided with a round hole 504 and a screw 505. The steel strand 4 passes through the round hole 504, and the screw 505 fixes the bottom anchoring device 5 to the top plate 10 of the steel box girder, further improving the structural stability.

[0055] Preferably, the long sling unloading device of the suspension bridge further includes an anti-slip cushion block 7, which is fixed to the movable anchor backing plate 502 and abuts against the end of the wedge-shaped cushion block 501.

[0056] A method for unloading the long sling of a suspension bridge, which is applied to the long sling unloading device of the suspension bridge. The suspension bridge includes a steel box girder top plate, a sling steel sleeve, a cable clamp, a main cable, and slings respectively connected to the steel box girder top plate and the main cable. The long sling unloading device of the suspension bridge includes a through-hole jack, a through-hole lifting beam, a cable gripper, a steel strand, a bottom anchoring device, and an anti-torsion device, and includes the following steps:

[0057] Sling locking step: Fix the cable gripper to the sling, and the through-hole lifting beam fixes the sling.

[0058] Pre-tightening step: Install the through-hole jack on the through-hole lifting beam, pass one end of the steel strand through the through-hole jack, connect the other end to the bottom anchoring device, and fix the bottom anchoring device on the steel box girder top plate.

[0059] Anti-torsion step: Install the anti-torsion device on the cable gripper.

[0060] Unloading step: The through-hole jack operates to completely unload the sling along the cable gripper 3 to the bottom.

[0061] Demolition step: Demolish the anchoring structure of the sling.

[0062] The process steps of unloading and demolishing the old sling are as follows:

[0063] ① The first step: Pull out a long pin rod 303 of the cable gripper 3, rotate the cable gripper 3 by an appropriate angle and hold it at a predetermined position at the bottom of the sling 9, and then reinstall the pulled-out long pin rod 303 in place to complete the installation of the cable gripper 3 on the sling 9.

[0064] ② The second step: Close the two semi-circular grooves 201 of the two half-blocks of the through-hole lifting beam 2 to wrap the sling 9, connect them into a whole through high-strength bolts 204, then support them on the cable gripper 3, and adjust to a predetermined posture.

[0065] ③ The third step: Install the through-hole jack 1 at a predetermined position on the through-hole lifting beam 2, after temporary fixation, pass the steel strand 4 through the through-hole jack 1 and the through-hole lifting beam 2, and install a single-hole anchor 6 of the steel strand 4 on the top surface of the through-hole jack 1.

[0066] ④ Connect and fix the two wedge-shaped cushion blocks 501 of the bottom anchoring device 5 to the fixed anchor backing plate 503 through screws 505, place the sling 9 into the gap between the two wedge-shaped cushion blocks 501 of the bottom anchoring device 5, and fix it through screws 505.

[0067] ⑤Insert the bottom of the steel strand 4 into the sling steel sleeve 11 and into the steel box girder. Insert the bottom of the steel strand 4 into the round holes 504 on the movable anchor backing plate 502 and the fixed anchor backing plate 503 of the bottom anchoring device 5, and then install the single-hole anchor 6 at the bottom of the steel strand 4 at the bottom.

[0068] ⑥Install the anti-slip pad 7 on the extended part of the movable anchor backing plate 502 to form an effective support between the bottom anchoring device 5 and the side plate of the steel box girder.

[0069] ⑦Install the anti-torsion device 8 in the middle area between the sides of the two wire gripers 3 to form an effective connection that restricts torsion between the two wire gripers.

[0070] ⑧After all components of the unloading device are installed, the 4 through-hole jacks 1 are synchronously oiled and tensioned until the end section of the sling 9 from the bottom of the wire griper 3 to the anchor head anchorage is completely unloaded, and then the anchor head anchorage structure of the sling 9 is removed when it is not stressed at the anchor head.

[0071] ⑨After the anchor head anchorage structure of the sling 9 is removed, the 4 through-hole jacks 1 are synchronously oiled and the cylinders are retracted until the steel strand 4 is completely relaxed and unloaded. At this time, the full-length unloading of the entire sling 9 is completed and the sling 9 is no longer stressed.

[0072] ⑩Remove all components of the unloading device of the present invention, and then remove the lower cable clip 12 and the main cable 13 from the non-stressed sling 9. Thus, the unloading and removal of the sling 9 are completed in a safe and stable state.

[0073] The specific working principle is as follows:

[0074] Use the wire griper to hold the old sling to be removed, and then use the wire griper as the upper anchoring point of the unloading device. The wire griper works on the principle of wedge self-locking. It can be installed on the old sling. When the through-hole jack of the unloading device is tensioned, the tension of the steel strand will be transmitted from the through-hole jack and the through-hole balance beam to the wire griper in sequence, thereby pushing the clamping block of the wire griper downward. The wedge block of the wire griper will not slip on the old sling, that is, the clamping block of the wire griper will tightly hold the old sling through the wedge sliding surface inside it and the holding block, achieving a firm connection with the old sling.

[0075] The bottom anchoring device of the unloading device is installed on the bottom surface of the top plate of the steel box girder for the bottom anchoring of the steel strand of the unloading device. By tensioning the steel strand with the through-hole jack, the force of the old sling to be removed is transferred from the inner anchor head backing plate of the steel box girder to the top plate of the steel box girder above it.

[0076] The unloading of the old sling is carried out in two stages. In the first stage, the prestressing of the steel strand is realized through the hole-through jack of the unloading device to transfer the force of the bottom section of the sling, so as to unload the bottom section and the anchor head anchorage, and the purpose of this stage is to unload the old sling anchor head anchorage to meet the condition for the removal of the old sling anchor head anchorage structure; in the second stage, the oil return and cylinder retraction operation is carried out on the hole-through jack of the unloading device to make the steel strand of the unloading device "slack" and unload, and then the old sling follows the "slack" unloading from above the cable grip to the range of the cable clip. The purpose of this stage is to unload the whole length of the old sling to meet the condition for removing the whole old sling from the main cable at the cable clip.

[0077] The force conduction path before the unloading of the old sling is: main cable → cable clip → sling wire rope body → sling anchor head → internal anchor plate in the steel box girder; after the first-stage unloading of the old sling using the unloading device of the present invention, the force conduction path changes to: main cable → cable clip → sling wire rope body → cable grip → hole-through flat beam → hole-through jack → steel strand → bottom anchorage device → top plate of the steel box girder.

[0078] ⑤ Since the angle of the top surface of the wedge-shaped pad of the bottom anchorage device of the unloading device should be the same as the angle of the top plate of the steel box girder at the anchorage, when the top plate of the steel box girder is an inclined plane, after the steel strand of the unloading device is prestressed, a component force parallel to the top surface of the steel box girder will be generated on the bottom anchorage device. When the frictional resistance between the bottom anchorage device and the top plate of the steel box girder is not sufficient to resist this component force, the bottom anchorage device will slide along the inclined plane. This problem can be effectively solved by setting anti-slip pads.

[0079] ⑥ Due to the structure of the wire rope sling body, when the force on the wire rope increases or decreases, without effective restraint, the wire rope will twist accordingly with the change of the force. For the construction of replacing the sling of a suspension bridge, the control of the twist of the wire rope sling is one of the key points of the construction, otherwise it will seriously affect the structural force safety of the old sling in the stressed state. The anti-twist device provided by the present invention can effectively solve the problem of sling twist during the unloading of the old sling. The anti-twist device is used in cooperation with the cable grip. By means of a screw, the two cable grips are clamped and connected into one body by a clamping beam, which can limit the twisting tendency of the two cable grips to each other, so that the cable grip cannot twist with the sling, and thus the sling cannot twist. The above embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A long sling unloading device for a suspension bridge, which is applied to a suspension bridge. The suspension bridge includes a steel box girder top plate, a sling steel sleeve, a cable clamp, a main cable, and slings respectively connected to the steel box girder top plate and the main cable. It is characterized in that: The long sling unloading device for a suspension bridge includes a hole-through jack, a hole-through crossbeam, a cable gripper, a steel strand, and a bottom anchoring device; The hole-through crossbeam includes two bodies, each body is provided with a semi-circular groove, the sling is located in the semi-circular groove and is fixed by the two bodies; two hole-through jacks are correspondingly arranged for each hole-through crossbeam, the sling is located in the middle of the hole-through crossbeam, and the two hole-through jacks are distributed on both sides of the sling; one end of the steel strand is fixed to the bottom anchoring device, and the other end is fixed to the hole-through jack; Each set of the bottom anchoring device includes 2 wedge-shaped pads, 1 movable anchor plate, 1 fixed anchor plate and 4 screws. The two wedge-shaped pads are arranged in parallel at intervals, and the interval is greater than the diameter of the sling; the fixed anchor plate and the movable anchor plate are arranged at the bottom of the two wedge-shaped pads. The fixed anchor plate is fixed to the wedge-shaped pad by screws, and the movable anchor plate is fixed to the wedge-shaped pad by screws. And the interval between the fixed anchor plate and the movable anchor plate is greater than the diameter of the sling. A round hole for the steel strand to pass through is drilled in the middle of both the fixed anchor plate and the movable anchor plate, and the diameter of the round hole is greater than the diameter of the steel strand; The cable gripper is covered and fixed on the sling, the hole-through jack is installed on the hole-through crossbeam, the bottom anchoring device is fixed to the top plate of the steel box girder, the top surfaces of the two wedge-shaped pads are abutted against the top plate of the steel box girder, and one ends of the two steel strands pass through the round holes of the fixed anchor plate and the movable anchor plate respectively from the gap between the two wedge-shaped pads and are respectively fixed to the fixed anchor plate and the movable anchor plate, and the other ends are respectively fixed to the two hole-through jacks. By controlling the steel strand through the hole-through jack, the part of the sling extending downward along the cable gripper becomes a stress-free section and the unloading is completed; It further includes an anti-torsion device. The anti-torsion device is installed on the sides of the two cable grippers. The installation heights of the two cable grippers are kept consistent and are respectively installed at the height positions of 1.5 m - 2.0 m at the bottoms of the two slings. The two hole-through crossbeams are respectively installed and supported on the two cable grippers; the anti-torsion device includes 2 clamping beams, 8 anchor plates, 4 screw rods and matching nuts. The screw rods lock the two clamping beams tightly on the cable grippers through the anchor plates and nuts, thereby connecting the two cable grippers into a whole.

2. The long sling unloading device for a suspension bridge according to claim 1, wherein: The hole-through crossbeam is further provided with two semi-long grooves and a plurality of bolt holes. The semi-circular groove is located between the two semi-long grooves, and the bolt holes are uniformly distributed at both ends of the hole-through crossbeam.

3. The long sling unloading device for a suspension bridge according to claim 2, characterized in that: The hole-through crossbeam further includes high-strength bolts. The high-strength bolts pass through the bolt holes to fix the two bodies and the sling.

4. The long sling unloading device for a suspension bridge according to claim 1, characterized in that: The long sling unloading device for the suspension bridge further includes a plurality of single-hole anchors. The end of the steel strand is clamped and abutted against the single-hole anchor, and the single-hole anchor is arranged on the hole-through jack and the bottom anchoring device.

5. The long sling unloading device for a suspension bridge according to claim 1, characterized in that: The clamping beam is made of back-to-back channel steel. The distance between the back-to-back channel steels is greater than the diameter of the screw rod. A round hole is drilled in the middle of the anchor plate, and the diameter of the round hole is greater than the diameter of the screw rod.

6. The long sling unloading device for a suspension bridge according to claim 5, characterized in that: It further includes anti-slip pads which are installed on the higher side of the bottom anchoring device, supported on the top surface of the movable anchor backing plate, and form a support between the bottom anchoring device and the inner side plate of the steel box girder.

7. The long sling unloading device for a suspension bridge according to claim 6, characterized in that: The cable gripper includes two clamping blocks, two cable gripping blocks and a long pin shaft. One ends of the two cable gripping blocks are hinged, and the other ends are fixed by the long pin shaft.

8. The long sling unloading device for a suspension bridge according to claim 6, characterized in that: The fixed anchor backing plate is provided with a round hole and a screw. The steel strand passes through the round hole, and the screw fixes the fixed anchor backing plate to the bottom of the wedge-shaped pad.

9. A method for unloading long slings of a suspension bridge, applied to a long sling unloading device of a suspension bridge as claimed in any one of claims 1 to 8, wherein the suspension bridge comprises a steel box girder top plate, a sling steel sleeve, a cable clamp, a main cable and slings respectively connected to the steel box girder top plate and the main cable, and the long sling unloading device of the suspension bridge comprises a through-type jack, a through-type shoulder beam, a cable gripper, a steel strand, a bottom anchoring device and an anti-twist device, characterized in that: It includes the following steps: Cable locking step: Fix the cable gripper to the sling, and the through-type lifting beam envelopes the sling and is supported on the top surface of the cable gripper; Pre-tightening step: Install the through-type jack on the through-type lifting beam, pass one end of the steel strand through the through-type jack, connect the other end to the bottom anchoring device, and fix the bottom anchoring device on the top plate of the steel box girder; Anti-twist step: Install the anti-twist device on the sides of the two cable grippers; Unloading step: Operate the through-type jack to completely unload the sling along the cable gripper to the bottom; Demolition step: Demolish the anchoring structure of the sling.

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