Bridge large cantilever flange plate reinforcing construction method

Abstract

The application discloses a bridge large cantilever flange plate reinforcing construction method, and solves the problem of bridge asphalt paving layer cracking caused by the negative bending moment phenomenon existing in the prior large cantilever flange plate reinforcing process. The method uses a jack, a steel wire rope and a steel rib plate to reinforce the old bridge after correction, applies a reverse force before paving concrete, makes the flange plate in a state of being upturned, and reinforces the steel fiber in the state, which is the first stage, wherein the concrete, the steel fiber and the steel rib plate are used to restore the overall stiffness of the bridge. Before asphalt paving, a counterweight is applied to simulate the state of the bridge deck with a vehicle load, and the counterweight is removed after asphalt paving is completed; under the combined action of the flange plate and the concrete, the steel fiber and the steel rib plate, the asphalt pavement is in a compressed state, thereby solving the problem of bridge asphalt paving layer cracking, and improving the construction quality and construction effect of the bridge deck.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology. Background Technology

[0002] After several years of service, especially decades, cast-in-place concrete box girders may experience problems such as cantilever sag and road surface cracking at the cantilever due to design flaws in the cantilever structure. The cause of these problems is the negative bending moment effect. Therefore, it is necessary to strengthen the cantilever structure.

[0003] Existing reinforcement methods include:

[0004] Steel plate reinforcement is a method based on adding triangular support plates at the cantilever on the back (lower surface) of the bridge. The cantilever is lifted by the lifting effect of the triangular support plates, thereby solving the problem. For example, ZL2017216758297 discloses a steel support structure for reinforcing the flange plate of a large cantilever of a bridge. It is supported on the lower edge of the bridge cantilever and the outer side of the web plate, including a base plate, ribs and flanges. The base plate has an irregular shape that fits with the lower edge of the cantilever and the outer side of the web plate. The ribs have irregular edge shapes that fit with the base plate. The irregular edge ribs are welded to the base plate. The base plate is fixed to the lower edge of the bridge cantilever and the outer side of the web plate by anchor bolts and grout.

[0005] Carbon fiber plate or carbon fiber cloth reinforcement refers to the method of attaching materials with high tensile strength, such as carbon fiber cloth or steel plate, to the tension position of the cantilever to improve the tensile strength of the component.

[0006] The reinforcement method of high-strength carbon fiber concrete involves milling the asphalt on the bridge deck with a milling machine, then repaving high-strength steel fiber concrete to thicken the bridge deck section, and finally laying a thin layer of asphalt.

[0007] The three reinforcement methods mentioned above each have their own advantages and disadvantages. For example, using high-strength steel fiber reinforced concrete to repave can increase the bending resistance of the bridge deck, but problems such as cantilever protrusion and road surface cracking at the cantilever still exist. In other words, the above solutions are not sufficient to effectively improve the bending resistance at the large cantilever flange. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method for reinforcing bridge cantilever flange plates, which solves the problem of cracking in the asphalt pavement layer of the bridge deck caused by the negative bending moment phenomenon in existing large cantilever flange plate reinforcement processes, thereby improving the reinforcement quality.

[0009] The technical solution adopted by this invention to solve its technical problem is as follows:

[0010] 1. A method for reinforcing the flange plate of a large cantilever bridge, characterized by the following steps performed in sequence:

[0011] S1 removed the ancillary facilities on the old bridge and carried out milling and planing of the asphalt on the bridge surface, which was then cleaned to form a rough concrete surface.

[0012] S2 uses an ultrasonic low-frequency tomographic imaging instrument to detect the transverse prestressed steel strands and main reinforcements in the flange plate, and marks the bridge surface where the prestressed steel strands and main reinforcements are located with ink lines, and marks them with red paint 5cm to the left and right of the ink lines. Drilling is strictly prohibited in this area. Drill holes in the flange plate and install studs. Along the longitudinal direction of the bridge, lay out and draw lines on the surface of the flange plate for the installation positions of the positioning device and jacks.

[0013] S3 drills holes for the installation points of the positioning device and jacks based on the layout and marked positions.

[0014] S4 uses a truck crane to lift the jack to the installation point, ensuring that the bolt holes on the jack are aligned with the drill holes on the flange plate before installing the jack.

[0015] S5 uses a truck crane to lift the positioning device to the layout position, ensuring that the bolt holes on the positioning device are aligned with the drill holes on the flange plate and then installs the positioning device.

[0016] S6 uses steel wire ropes to mechanically connect the steel wire rope installation parts at the top of the jack, forming a cross-shaped connection network;

[0017] S7 attaches strain gauges to the back of the flange plate and applies load using jacks. The loading process is slow, and the pressure gauges on the jacks are observed. The data from the strain gauges is then combined with the data from the strain gauges to make a comprehensive judgment. When the load meets the design requirements, the jack loading is stopped.

[0018] The S8 steel fiber filaments are wound by first fixing the steel fiber filaments to a stud, then arranging them along the transverse direction of the bridge, going back and forth, and then folding back at the studs on the other flange plate. In a top view, the steel fiber filaments are arranged in a parallel and crisscrossing manner and wound between the studs. Side formwork is installed along the edge of the bridge, and cylindrical formwork is set at the jack installation point. Then, the steel fiber reinforced concrete is laid. During the laying process, the following principles are followed: the laying is carried out along the transverse direction of the bridge and back and forth, and finally the surface is smoothed and cured to the design hardness.

[0019] S9 fixes one end of the L-shaped scaffolding component to the positioning device, and the other end is fixed to the bottom plate of the box girder. A wooden board is placed along the bridge direction to form a standing platform; the steel rib plate is hoisted to the box girder and fixed.

[0020] The S10 jack was unloaded and removed, and concrete mortar was applied to the jack installation point to slowly release the tensile stress of the wire rope and make the flange plate and steel rib plate fit more tightly.

[0021] S11. A counterweight device is added below the fixing device to simulate the negative bending moment state when there are vehicles on the bridge deck. Under this state, elastic asphalt is laid. After the paving is completed, the counterweight device is removed immediately. Finally, the positioning device is removed, and auxiliary facilities are installed, and the installation points of the positioning device on both sides of the bridge are repaired.

[0022] Furthermore, the counterweight device is a suspended water tank or a precast concrete block, with a weight approximately equal to the maximum load designed for passing vehicles.

[0023] Furthermore, the spacing between adjacent studs is no more than half a meter, and the exposed height of the studs is approximately equal to the thickness of the high-strength concrete paving layer.

[0024] Furthermore, after the steel rib is installed, its upper surface abuts against the lower surface of the flange plate. The top of the steel rib has a grouting groove, and the upper edge of the grouting groove is in contact with the flange plate or has a slight gap, which is controlled within 2 mm. The adhesive plate is embedded in the grouting groove in the shape of a strip, and the thickness of the adhesive plate is not less than 3 mm. Rubber sealing is provided around the perimeter. Threaded holes are drilled on the bottom plate of the grouting groove corresponding to the adhesive plate, and tightening bolts are installed. The adhesive plate is lifted up and attached to the lower surface of the flange plate by tightening bolts.

[0025] Furthermore, a grouting channel is formed between the grouting groove and the bonding plate, and grouting is performed.

[0026] Furthermore, the positioning device is a welded steel structure, the main body of which is a U-shaped channel steel plate, forming a clamping space for clamping the flange plate. An upwardly extending ear plate is welded to the top plate of the U-shaped channel steel plate, and the ear plate has a rope loop for tying a steel wire rope. A downwardly extending vertical plate is welded to the bottom plate of the U-shaped channel steel plate, and the vertical plate has a round hole.

[0027] The wire rope mounting component is installed on the piston of the hydraulic jack via a threaded connection. The wire rope mounting component is star-shaped and has N wire rope fixing holes.

[0028] The beneficial effects of this invention are as follows: This construction process improves upon traditional construction methods. Specifically, instead of direct paving, a reverse force is applied before concrete paving, causing the flange plates to be in an upward-curved state. Steel fiber reinforcement is then performed in this state; this is the first stage. The concrete, steel fibers, and steel ribs are used to restore the overall stiffness of the bridge. Furthermore, a counterweight is applied before asphalt paving to simulate a vehicle-loaded bridge deck. After asphalt paving is completed, the counterweight is removed. Under the combined action of the flange plates, concrete, steel fibers, and steel ribs, the asphalt pavement is under compression, thus solving the problem of cracking in the asphalt paving layer and improving the construction quality and effect of the bridge deck. Attached Figure Description

[0029] Figure 1 This refers to the construction of bridges in the existing technology.

[0030] Figure 2 This is a standard section cross-section diagram of an existing box girder.

[0031] Figure 3 This is a schematic diagram of the construction process nodes of the present invention.

[0032] Figure 4 This is a schematic diagram of the construction process nodes of the present invention.

[0033] Figure 5 This is a schematic diagram of the construction process nodes of the present invention.

[0034] Figure 6 This is step S1 of the construction process.

[0035] Figure 7 This is step S2 of the construction process.

[0036] Figure 8 This is step S3 of the construction process.

[0037] Figure 9 This is step S4 of the construction process.

[0038] Figure 10 for Figure 9 A perspective from below.

[0039] Figure 11 This is step S5 of the construction process.

[0040] Figure 12 This is step S6 of the construction process.

[0041] Figure 13 for Figure 12 A perspective from below.

[0042] Figure 14 This is a three-dimensional view of the positioning device.

[0043] Figure 15 This is a three-dimensional view of the positioning device.

[0044] In the picture:

[0045] 00 Box girder, 01 Flange plate, 02 Vertical rib, 011 Stud, 012 Steel fiber optic cable, 013 Steel fiber reinforced concrete, 014 Elastic asphalt, 03 Box girder bottom plate.

[0046] 100 Positioning device, 110 U-shaped channel steel plate, 011 Bolt, 120 Clamping space, 130 Ear plate, 131 Tie ring, 140 Vertical plate, 141 Round hole.

[0047] 200 scaffolding components, 210 wooden planks,

[0048] 300 steel ribs,

[0049] 400 steel wire rope,

[0050] 500 hydraulic jack, 510 steel wire rope installation parts

[0051] 600 counterweight device. Detailed Implementation

[0052] This invention relates to a method for reinforcing the flange plates of bridge cantilever beams. This method is specifically designed for precast reinforced concrete box girders. In this embodiment, the large cantilever flange plate refers to a cantilever structure with a cantilever width of not less than 5 meters. Due to the negative bending moment at the flange plate location, after long-term service, the flange plates on both sides of the precast box girder experience sagging, resulting in cracks in the bridge deck at the joint between the flange plate and the box girder. Therefore, reinforcement is necessary to prevent further damage.

[0053] After the implementation of this reinforcement technology, a prestressed rigid concrete layer is added to the bridge deck, which contains prestress (tension) to suppress the negative bending moment generated by the flange plate.

[0054] This embodiment is described in conjunction with the appendix to the instruction manual. Figure 1 To be continued Figure 15 This paper provides a detailed explanation of the technology.

[0055] refer to Figure 14 The positioning device 100 is mechanically fixed to the edges of the flange plates 01 on both sides of the box girder 00. This positioning device is custom-designed according to the shape of the flange plates. The positioning device 100 adopts a welded steel structure, with the main body being a U-shaped channel steel plate 110, forming a clamping space 120 for holding the flange plates 01. This clamping space 120 is a horizontally placed U-shape. Expansion bolts are drilled and installed on the top, bottom, and sides of the U-shaped channel steel plate 110 for fixation. An upwardly extending ear plate 130 is welded to the top plate of the positioning device 100. This ear plate has a wire rope tie ring 131 for fixing the wire rope.

[0056] A downwardly extending vertical plate 140 is welded onto the base plate of the U-shaped channel steel plate. The vertical plate 140 has a circular hole 141. The vertical plate is used to install the scaffolding component 200.

[0057] The positioning device 100 is welded using Q345 steel, employing bevel penetration welding and featuring transverse stiffening ribs across the weld seam, achieving a first-class weld seam.

[0058] The plate in the positioning device is made of 20 mm thick steel plate, which is attached to the top surface of the flange, the side surface of the flange, and the lower surface of the flange.

[0059] Further, refer to Figure 15The aforementioned positioning device features an extended vertical plate design, which allows for the installation of two circular holes.

[0060] Further, refer to Figures 8 to 10 The scaffolding component 200 is an L-shaped steel component. One end of the L-shaped steel component is fixed to the bottom and side corners of the box girder by expansion bolts, and the other end is connected to the round holes on the vertical plate by high-strength bolts to form multiple parallel scaffoldings. Wooden planks are laid along the bridge direction to form a platform for workers to stand on and for assisting in the installation of precast steel ribs 300.

[0061] The steel rib plate 300 is a steel rib plate. The vertical surface of the steel rib plate is attached to the outer surface of the box girder and fixed with expansion bolts. The steel rib plate strengthens the flange plate from below, improving the bending strength of the flange plate.

[0062] 400 steel wire rope, 500 steel wire rope connecting hydraulic jack and 100 positioning device.

[0063] 500 hydraulic jacks, in several quantities. These hydraulic jacks are set vertically, with one end abutting against the bridge deck directly above the vertical rib 02 of the box girder 00. Due to the presence of the vertical rib, the bearing capacity at this location is the strongest, which can reduce the impact on the original structure during the jack construction process.

[0064] A wire rope mounting component 510 is fixed on the top of the piston of the hydraulic jack 500. The wire rope mounting component is shaped like a quincunx or a star, and has N wire rope fixing holes for fixing the wire rope. When the hydraulic jack is lifted, the wire rope causes the flange plate to have an upward bending tendency, that is, the flange plate produces an upward correction action. When concrete is poured in this state, it can generate a prestressing effect.

[0065] The construction method is as follows:

[0066] S1 Demolition of Structures on the Old Bridge

[0067] The old bridge's ancillary facilities, including sound barriers, steel railings, sidewalks, and railing beam foundations, were removed. The asphalt surface of the bridge deck was then milled and cleaned to create a rough surface.

[0068] S2 scans the steel strands present in the steel-concrete composite plate of the flange 01 and marks their locations.

[0069] Ultrasonic low-frequency tomography was used to detect the transverse prestressed steel strands and main reinforcement bars at the construction site of the flange plate. In order to more accurately avoid the prestressed steel strands and main reinforcement bars, the area of ​​the original steel strand corrugated pipe was marked with ink lines and the original steel strand corrugated pipe area was located. The area of ​​the prestressed steel strands and main reinforcement bars was marked with red paint 5cm to the left and right of the original steel strand center. Drilling in this area is strictly prohibited to avoid damage to the prestressed steel strands.

[0070] On the above flange plate 01, refer to Figure 6 , drill holes, which are through holes in this embodiment. Install stud bolts 011 in the through holes. The spacing of the stud bolts 011 should not be greater than half a meter to ensure sufficient density. The stud bolts are clamped in the above through holes, and the exposed height of the stud bolts is approximately equal to the thickness of the high-strength concrete paving layer.

[0071] Along the longitudinal direction of the bridge, at the position of the flange plate 01, lay out and draw lines for the positioning device according to the site. The spacing between adjacent positioning devices is several meters. For example, set the interval to 8 meters. And determine the position of the jack, and lay out and draw lines.

[0072] S3 Drilling

[0073] Drill holes at the installation points of the positioning device 100 according to the layout and marking positions. The drill holes are located at the position near the edge of the flange plate 01 and are straight through holes up and down, that is, penetrating up and down. These drill holes are used for the fixation of the positioning device, and high-strength bolts are used for fixation.

[0074] This process does not require cleaning and roughening of the layout points, and can be directly fixed. This mechanical fixation method is also beneficial for the later removal of the positioning device 100.

[0075] In this structure, the high-strength bolts mainly bear the shear force perpendicular to the axial direction of the bolts. Therefore, there is no risk of the bolts being pulled out.

[0076] Furthermore, the high-strength bolts are preferably 8.8S grade M16 high-strength bolts. During the tightening process, appropriate gaskets and tightening nuts are selected, and the gaskets correspond to the slope of the flange plate.

[0077] S4 Installation of hydraulic jack

[0078] Use a truck crane to hoist the hydraulic jack 500 to the layout position, ensure that the bolt hole positions on the jack are aligned with the drill hole positions on the flange plate, and then use expansion bolts to fix the jack, refer to Figure 7 .

[0079] S5 Installation of positioning device

[0080] Use a truck crane to hoist the positioning device 100 to the layout position, ensure that the bolt hole positions on the positioning device are aligned with the drill hole positions on the flange plate, and then use high-strength bolts for fixation.

[0081] S6 Installation of steel wire rope

[0082] Adopt a "day" - shaped connection between two adjacent rows of jacks, and make an oblique connection between the diagonally opposite jacks. The connection adopts a pre - tightening method, that is, ensure that the steel wire ropes are fully tightened, refer to Figure 7Furthermore, steel wire ropes are pre-tightened to the corresponding installation devices on the outside of the jacks, forming a cross-shaped structure with each jack. This structure fully ensures the safety of the jacks during construction.

[0083] S7 loading

[0084] Strain gauges are attached to the back (lower surface) of the flange plates. These gauges are used in conjunction with jacks for lifting and loading. The loading process is slow, and the pressure gauges of the hydraulic jacks are carefully observed. The applied load is then assessed in stages, taking into account the data from the strain gauge readings. During the slow loading process, the flange plates on both sides of the box girder exhibit an upward tilting motion; that is, from a vertical cross-section, the flange plates are in a positive bending moment state. Loading is stopped when the strain gauge readings meet the design requirements.

[0085] The S8 steel fiber filaments are wound by fixing the first end of a φ0.1 mm steel fiber filament 012 to a stud 011. The steel fiber filament 012 is then arranged transversely along the bridge, meandering back and forth, and folded back at the stud on the other flange plate. This process creates prestressing assistance for the steel fiber filaments on the bridge deck, and during the winding process, the steel fiber filaments are in a pre-tensioned state, i.e., under tension. From a top view, the steel fiber filaments are arranged in a parallel and crisscrossing manner, and have different heights along the vertical direction, as shown in the reference. Figure 7 Temporarily fix square timber around the bridge to form the side formwork for pouring. Temporarily fix circular cylindrical formwork at the jack locations to isolate the jack installation areas. Then, pave the steel fiber reinforced concrete 013, following these principles: paving should be done along the transverse direction of the bridge, repeating back and forth, and finally smoothed. (Refer to...) Figure 8 Maintenance for 48 hours.

[0086] Installation of S9 access platform and steel ribs

[0087] One end of the L-shaped scaffolding component 200 is fixed to the aforementioned positioning device with high-strength bolts. After a reliable connection is established, the other end is fixed to the bottom plate 03 of the box girder with high-strength bolts. Wooden planks 210 are then erected along the bridge direction to form a standing platform.

[0088] The steel rib plate 300 was lifted to the box girder using a truck crane and pulley assembly, and secured with high-strength bolts, such as expansion bolts. During the tightening process, holes were drilled at the mounting points of the steel rib plate 300 to install the expansion bolts and fix the steel rib plate. After installation, the upper surface of the steel rib plate 300 abutted against the lower surface of the flange plate. (The last sentence appears to be incomplete and possibly refers to a reference to a different steel rib plate.) Figure 7The top of the steel rib has a grouting groove, the upper edge of which is in just contact with the flange plate 01, or with a slight gap, the gap being controlled within 2 mm. A strip-shaped bonding plate is embedded in the grouting groove, the thickness of which is not less than 3 mm, for example, a 4 mm steel plate bonding plate, and rubber sealing is provided around the perimeter to prevent grout leakage. Threaded holes are drilled in the bottom plate of the grouting groove corresponding to the bonding plate, and tightening bolts are installed. The bonding plate is lifted up and bonded to the lower surface of the flange plate by the tightening bolts. Since the lower panel of the flange plate has a certain curvature under the prestress of the wire rope, the bonding plate can better meet the bonding requirements.

[0089] The grouting groove and the bonding plate form a grouting channel. That is, the grouting process ensures a close contact between the steel rib and the flange, guaranteeing reliable contact. The presence of the steel rib can effectively reduce the deformation of the flange, thereby preventing cracking of the asphalt layer of the road surface.

[0090] S10 jack unloading and removal of jacks and wire ropes

[0091] The slow retraction of the hydraulic jack (500mm) allows the tensile stress in the wire rope to be released gradually. During this process, the flange plate tends to return to its original position, resulting in a tighter fit between the flange plate and the underlying steel rib plate. (Refer to...) Figure 8 and Figure 9 The jacks were removed and the groove where the installation point was located was repaired with concrete mortar to facilitate the next step of asphalt paving.

[0092] S11 and a counterweight device 600 is added below the fixed device via a counterweight block. This counterweight device is a suspended water tank or a precast concrete block, and its weight is approximately equal to the maximum load of the designed passing vehicles. During this process, the rotor plate is placed in a negative bending moment state. (Refer to...) Figure 5 and Figure 11 This is used to simulate the negative bending moment state of the bridge deck when there are vehicles. Under this state, the surface layer of elastic asphalt 014 is laid. After the paving is completed, the above-mentioned counterweight device is immediately removed. After the counterweight device is removed, the negative bending moment becomes smaller, and only the negative bending moment of the flange plate itself is present.

[0093] After implementation of this embodiment, the high-strength concrete of the bridge has been thickened and reinforced in its cross-section design. Simultaneously, this method ensures that the steel fiber filaments (bundles) within the thickened high-strength concrete layer are taut, causing upward deflection of the flanges on both sides (deflection – the linear displacement of the centroid of the cross-section perpendicular to the axis when a bridge undergoes transverse bending deformation is called deflection, i.e., vertical deformation). This deflection can offset part of the negative bending moment, mitigating the later-stage sagging and negative bending moment phenomena of the flanges.

[0094] Another benefit is that, in the paving of elastic asphalt, by applying counterweights, the elastic asphalt is placed under pressure after construction, thus solving the problem of easy cracking of the asphalt layer.

[0095] Finally, the positioning device was removed, and infrastructure such as guardrails, streetlights, and protective netting were installed. Local defects on both sides of the bridge were also repaired to complete the construction process.

[0096] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements to the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for reinforcing the flange plate of a bridge with large cantilever, characterized in that, Follow these steps in sequence: S1 removed the ancillary facilities on the old bridge and carried out milling and planing of the asphalt on the bridge surface, which was then cleaned to form a rough concrete surface. S2 uses an ultrasonic low-frequency tomographic imaging instrument to detect the transverse prestressed steel strands and main reinforcements in the flange plate, and marks the bridge surface where the prestressed steel strands and main reinforcements are located with ink lines, and marks them with red paint 5cm to the left and right of the ink lines. Drilling is strictly prohibited in this area. Drill holes in the flange plate and install studs. Along the longitudinal direction of the bridge, lay out and draw lines on the surface of the flange plate for the installation positions of the positioning device and jacks. S3 drills holes for the installation points of the positioning device and jacks based on the layout and marked positions. S4 uses a truck crane to lift the jack to the installation point, ensuring that the bolt holes on the jack are aligned with the drill holes on the flange plate before installing the jack. S5 uses a truck crane to lift the positioning device to the layout position, ensuring that the bolt holes on the positioning device are aligned with the drill holes on the flange plate and then installs the positioning device. S6 uses steel wire ropes to mechanically connect the steel wire rope installation parts at the top of the jack, forming a cross-shaped connection network; S7 attaches strain gauges to the back of the flange plate and applies load using jacks. The loading process is slow, and the pressure gauges on the jacks are observed. The data from the strain gauges is then combined with the data from the strain gauges to make a comprehensive judgment. When the load meets the design requirements, the jack loading is stopped. The S8 steel fiber filaments are wound by first fixing the steel fiber filaments to a stud, then arranging them along the transverse direction of the bridge, going back and forth, and then folding back at the studs on the other flange plate. In a top view, the steel fiber filaments are arranged in a parallel and crisscrossing manner and wound between the studs. Side formwork is installed along the edge of the bridge, and cylindrical formwork is set at the jack installation point. Then, the steel fiber reinforced concrete is laid. During the laying process, the following principles are followed: the laying is carried out along the transverse direction of the bridge and back and forth, and finally the surface is smoothed and cured to the design hardness. S9 fixes one end of the L-shaped scaffolding component to the positioning device, and the other end is fixed to the bottom plate of the box girder. A wooden board is placed along the bridge direction to form a standing platform; the steel rib plate is hoisted to the box girder and fixed. The S10 jack was unloaded and removed, and concrete mortar was applied to the jack installation point to slowly release the tensile stress of the wire rope and make the flange plate and steel rib plate fit more tightly. S11. A counterweight device is added below the fixing device to simulate the negative bending moment state when there are vehicles on the bridge deck. Under this state, elastic asphalt is laid. After the paving is completed, the counterweight device is removed immediately. Finally, the positioning device is removed, and auxiliary facilities are installed, and the installation points of the positioning device on both sides of the bridge are repaired.

2. The method for reinforcing the large cantilever flange plate of a bridge according to claim 1, characterized in that, The counterweight device is a suspended water tank or a precast concrete block, with a weight approximately equal to the maximum load designed for passing vehicles.

3. The method for reinforcing the large cantilever flange plate of a bridge according to claim 1, characterized in that, The spacing between adjacent studs shall not exceed half a meter, and the exposed height of the studs shall be approximately equal to the thickness of the high-strength concrete paving layer.

4. The method for reinforcing the large cantilever flange plate of a bridge according to claim 1, characterized in that, After the steel rib is installed, its upper surface abuts against the lower surface of the flange. The top of the steel rib has a grouting groove, and the upper edge of the grouting groove is in contact with the flange or has a slight gap, which is controlled within 2 mm. The adhesive plate is embedded in the grouting groove in a long strip shape, with a thickness of not less than 3 mm, and rubber sealing is provided around it. Threaded holes are drilled on the bottom plate of the grouting groove corresponding to the adhesive plate, and tightening bolts are installed. The adhesive plate is lifted up and attached to the lower surface of the flange by tightening bolts.

5. The method for reinforcing the large cantilever flange plate of a bridge according to claim 4, characterized in that, A grouting channel is formed between the grouting groove and the bonding plate, and grouting is performed thereon.

6. The method for reinforcing the large cantilever flange plate of a bridge according to claim 1, characterized in that, The positioning device is a welded steel structure, the main body of which is a U-shaped channel steel plate, forming a clamping space for clamping the flange plate. An upwardly extending ear plate is welded to the top plate of the U-shaped channel steel plate, and the ear plate has a rope loop for tying a steel wire rope. A downwardly extending vertical plate is welded to the bottom plate of the U-shaped channel steel plate, and the vertical plate has a round hole.

7. The method for reinforcing the large cantilever flange plate of a bridge according to claim 1, characterized in that, The wire rope mounting component is installed on the piston of the hydraulic jack via a threaded connection. The wire rope mounting component is star-shaped and has N wire rope fixing holes.

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