Method for controlling the top layer of a bridge deck pavement reinforcement mat and device therefor

Abstract

This invention relates to a method and apparatus for controlling the top protective layer of steel mesh reinforcement in bridge deck paving. It employs a method to align the lower ends of the limit markers on a steel mesh elevation trolley with the same horizontal straight line, thus controlling the top surface of the steel mesh to the same horizontal plane as the design elevation requirement. This invention overcomes the limitations of traditional methods that rely on the top surface of the bridge slab for controlling the steel mesh elevation, which is susceptible to changes in the prestress of the bridge slab. By using a steel mesh elevation trolley, this invention controls the top surface of the steel mesh at the design elevation, eliminating the influence of changes in the prestress of the bridge slab. This invention effectively controls the thickness of the top protective layer of the steel mesh reinforcement in bridge deck paving, effectively preventing bridge deck cracking, deformation, and collapse, and significantly extending the service life of the bridge.

Description

Technical Field

[0001] This invention relates to a method and apparatus for controlling the top protective layer of steel mesh in bridge deck paving. Background Technology

[0002] Bridge deck paving is the final step in bridge engineering, and the installation of the reinforcing mesh is a crucial part of the paving process. The reinforcing mesh is a steel mesh component used to strengthen and protect the concrete bridge deck. It is made of interwoven high-strength steel bars. The paving process involves first laying the reinforcing mesh on the top surface of the bridge deck, and then pouring concrete on top of the mesh, placing the reinforcing mesh within the concrete pavement to form a protective concrete layer. The reinforcing mesh primarily enhances the load-bearing capacity of the concrete bridge deck, preventing cracking, deformation, and collapse, thus extending the bridge's service life. When the horizontal distance between the reinforcing mesh and the top surface of the concrete deck meets requirements and is horizontally distributed—meaning the thickness of the protective layer (concrete) on top of the reinforcing mesh is consistent and meets requirements—the load-bearing capacity of the concrete bridge deck is further enhanced, and cracking, deformation, and collapse are more effectively prevented.

[0003] Controlling the horizontal distance between the reinforcing mesh and the top surface of the bridge deck concrete to ensure it meets requirements and is horizontally distributed is a technical challenge in bridge deck reinforcing mesh installation. Currently, bridge deck reinforcing mesh installation uses a controlled elevation band method, employing 4×4cm angle steel. The angle steel is placed 15cm from the inner edge of the guardrail and along the centerline of the bridge deck. Measurements are taken every 5m from control points to determine the elevation of the top surface of the bridge deck, calculate the paving thickness, and provide this information to the angle steel installers. After installation, the elevation of each angle steel point is precisely measured, and the angle steel is leveled using string lines. The elevation is checked every 2m, and the stability and height difference of the angle steel joints are also inspected. This traditional controlled elevation band method relies on the top surface of the bridge deck. However, the top surface of the bridge deck is often affected by previous processes, causing local elevations to not meet design requirements. This is especially true for bridges that were initially simply supported and then made continuous, where prestressing causes a pre-camber in the middle of the bridge deck, affecting the elevation of the angle steel on the top surface. Therefore, simply designing and installing support bars or directly laying steel mesh according to the elevation control method cannot effectively control the thickness of the top protective layer of the steel mesh on the bridge deck, and cannot effectively prevent bridge deck cracking, deformation and collapse, thus affecting the service life of the bridge. Summary of the Invention

[0004] The purpose of this invention is to design a control method and device for the top surface protective layer of steel mesh in bridge deck paving, so as to control the top surface of the steel mesh at the design elevation and overcome the shortcomings of traditional control methods.

[0005] Therefore, the present invention provides a method for controlling the top protective layer of steel mesh in bridge deck pavement, comprising the following steps:

[0006] (1) Prepare the steel reinforcement protective layer elevation trolley, support base, and correction steel plate.

[0007] (2) Clean the bridge surface before laying the steel mesh.

[0008] (3) Support bases are set at intervals along the base of the bridge deck guardrails on both sides. A channel steel with a length of 11 to 20 m and a width of 20 to 30 cm is set on the upper surface of the support base on the same side. By setting a correction steel plate between the upper end of the support base and the lower end of the channel steel, the upper end of the channel steel on both sides is corrected to be on the same horizontal plane.

[0009] (4) Install a steel reinforcement protective layer elevation trolley on both sides of the upper end of the channel steel. The roller groups at the lower ends of the truss supporting the trolley are located on the upper ends of the channel steel on both sides. After manually moving the elevation trolley back and forth so that it can run along the upper ends of the channel steel on both sides, the upper edges of several baffles set at intervals are hinged to one side of the bottom edge of the trolley truss. The limit markers at the lower ends of the baffles are on the same straight line, and the lower ends of the limit markers on the same straight line are consistent with the design control elevation of the top surface of the steel mesh.

[0010] (5) Laying of steel mesh: The steel mesh is laid on the top surface of the bridge slab according to the design requirements. The top surface of the steel mesh is adjusted and controlled to be consistent with the design control elevation based on each limit marker, including the adjustment and control of the existing support bars and the adjustment and control of the pre-embedded support bars.

[0011] (a) Adjustment and control of existing support reinforcement: On the top surface of the bridge slab at the lower end of the laid steel mesh, mark the points of each existing support reinforcement to be installed according to the design requirements. Set four support reinforcement points at intervals per square meter. Manually move the steel reinforcement protective layer elevation trolley to the upper space of the steel mesh at each existing support reinforcement point in the transverse direction of the bridge slab, so that the lower end of each limit marker on the same straight line is on the same vertical plane as each existing support reinforcement point in the transverse direction. Fix the elevation trolley, and manually use a pry bar to lift the steel mesh so that the steel mesh... When the upper end face is aligned with the lower end face of each limit marker on the trolley, a support bar is welded to the lower end of the aligned steel mesh. The lower end of the support bar is supported at the corresponding marked installation support bar point, and the upper end of the support bar is welded to the lower end of the corresponding steel mesh. Support bars of different lengths are welded according to different parts to ensure that the top surface of the steel mesh is consistent with the design control elevation, thereby ensuring that the thickness of the protective layer of the upper steel mesh is consistent and meets the design and specification requirements when concrete is poured on the steel mesh in the subsequent process.

[0012] After the horizontal row adjustment and control welding support bars are completed, the upper end face of the horizontal steel mesh is aligned with the lower end face of each limit marker in the same straight line. Move the elevation trolley to the adjacent horizontal row where the support bars are to be installed. Repeat the adjustment and control welding support bar operation until the adjustment and control welding support bars of this channel steel section are completed.

[0013] (b) Adjustment and control of embedded support bars: The elevation trolley for the concrete cover is manually moved to the upper space of the steel mesh for the transverse embedded support bars of the bridge slab, so that the lower end face of each limit marker on the same straight line is on the same vertical plane as each transverse embedded support bar. The elevation trolley is fixed, and the steel mesh is manually pried up with a crowbar until the upper end face of the steel mesh is aligned with the lower end face of each limit marker on the trolley. Then, the embedded support bars at the lower end of the aligned steel mesh are corrected and adjusted with a crowbar or hammer, so that the upper end of the corrected and aligned embedded support bars is welded to the corresponding lower end of the steel mesh. The embedded support bars are corrected and adjusted according to different parts to ensure that the top surface of the steel mesh is consistent with the design control elevation, thereby ensuring that the thickness of the concrete cover on the upper part of the steel mesh is consistent and meets the design and specification requirements when concrete is poured on the steel mesh in the subsequent process.

[0014] After the peers have finished adjusting and controlling the embedded support bars for welding, the upper surface of the transverse steel mesh is aligned with the lower surface of each limit marker on the same straight line. Move the elevation trolley to each embedded support bar in the adjacent row and repeat the operation of adjusting and controlling the embedded support bars for welding until the adjustment and control of the embedded support bars for welding in this channel steel section is completed.

[0015] (6) Repeat step (3) to extend the forward channel steel rail, so that the moving elevation trolley moves to the adjacent adjustment control steel mesh top surface is consistent with the design control elevation. Repeat step (5), and use the cyclic method of removing the old and replacing the new forward channel steel rail to move the elevation trolley forward until the steel mesh is laid.

[0016] (7) Repair the steel mesh at the dismantled support base area so that the repaired steel mesh is at the same height as the steel mesh laid according to the design requirements.

[0017] As a further description of the above technical solution: the method for ensuring that the lower ends of the limit markers on the same straight line are consistent with the design control elevation of the top surface of the reinforcing mesh is as follows: (a) According to the designed elevation requirements of the protective concrete bridge deck layer, use a laser marker to mark the top surface line of the protective concrete bridge deck layer to be constructed on the lower part of the guardrails on both sides of the bridge deck to be constructed, and mark it with chalk as the control line for pouring the top surface of the protective concrete bridge deck layer. (b) Subtract the designed thickness of the top surface protective layer of the reinforcing mesh from the lower end of the control line, and mark the top surface control line of the reinforcing mesh with red chalk, and then verify it with a laser marker. (c) Adjust the lower ends of the limit markers on the reinforcing protective layer elevation trolley to be on the same horizontal straight line, and on the same horizontal plane as the control line of the top surface of the reinforcing mesh marked with red chalk.

[0018] As a further description of the above technical solution: the pre-embedded support bars at the lower end of the steel mesh that are adjusted and aligned by pry bar or hammer include raising the pre-embedded support bars that are lower than the design control elevation of the steel mesh by pry bar, or lowering the pre-embedded support bars that are higher than the design control elevation of the steel mesh by hammer.

[0019] As a further description of the above technical solution: the existing support bar is T-shaped, and the upper end of the vertical bar is fixed with a horizontal bar, which is welded to the steel mesh.

[0020] As a further description of the above technical solution: the repair of the steel mesh at the dismantled support base is that the longitudinal and transverse steel bars at both ends of the repair are overlapped with the corresponding longitudinal and transverse steel mesh of the surrounding area by a staggered length of 20cm, and the two steel bars at the overlap are tightly wrapped with wire. The two steel bars are overlapped side by side in a lateral manner, and the steel mesh at the repair site is on the same plane as the surrounding adjacent steel mesh.

[0021] As a further description of the above technical solution: the rebar protective layer elevation trolley includes a triangular truss spanning at least the length between the guardrails on both sides of the bridge deck, roller sets, baffles, and limiting rods. The triangular truss is formed by three metal rods arranged in a triangle, with each metal rod fixed to the other by several diagonally distributed reinforcing rods at intervals. Roller sets for moving the triangular truss are provided on the bottom two sides of the triangular truss. The upper surface of the wheel plate of each roller set is connected to the bottom two sides of the triangular truss. Wheel seats are provided at the four corners of the lower end of the wheel plate of the roller set. The rollers are connected to the wheel seats by axles. The running direction of the rollers is perpendicular to the axis of the bottom surface of the triangular truss. The upper surface of several baffles distributed at intervals is connected to one side of the bottom edge of the triangular truss by hinges, or the upper surface of several baffles distributed at intervals is connected to one side of the bottom edge of the triangular truss by adjusting steel wire ropes. Limiting rods are provided on the lower end of each baffle, and all limiting rods are on the same straight line.

[0022] As a further description of the above technical solution: the height of each baffle is the same, and each baffle near the upper edge of the baffle is provided with a through hole at the same size position.

[0023] As a further description of the above technical solution: the metal rod is an alloy aluminum rod or a steel pipe rod.

[0024] The present invention has the following beneficial effects:

[0025] 1. This invention changes the traditional method of controlling the elevation of the reinforcing mesh based on the top surface of the bridge slab. It also avoids the problem of the bridge slab's top surface being susceptible to prestressing, resulting in camber and consequently affecting the elevation of the reinforcing mesh, thus failing to effectively control the thickness of the protective layer at the top of the reinforcing mesh. This invention uses a reinforcing mesh elevation trolley to control the top surface of the reinforcing mesh at the design elevation, unaffected by changes in prestress on the bridge slab's top surface. This effectively controls the thickness of the protective layer at the top of the reinforcing mesh, preventing bridge cracking, deformation, and collapse, and significantly extending the bridge's service life.

[0026] 2. This invention has good application effects, and has the advantages of reasonable and simple design, strong practicality, convenient operation, significant efficiency, good stability, low construction cost, and saving time and labor. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the steel reinforcement protective layer elevation trolley in use according to the present invention;

[0028] Figure 2 This is a side view of the rebar protective layer elevation trolley of the present invention;

[0029] Figure 3 This is a top view of the rebar protective layer elevation trolley of the present invention;

[0030] Figure 4 This is a schematic diagram of the elevation control structure of the elevation trolley for the upper end of the steel mesh according to the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of the in-situ support rib of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. To facilitate understanding of the technical means, creative features, and achieved objectives and effects of the present invention, the present invention will be further elaborated below with reference to specific embodiments. However, the following embodiments are merely preferred embodiments of the present invention and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments without creative effort are all within the protection scope of the present invention. Unless otherwise specified, the construction methods in the following embodiments are conventional methods. Unless otherwise specified, the materials, devices, equipment, etc., used in the following embodiments can be obtained commercially.

[0033] like Figures 1 to 5 As shown, a method for controlling the top surface protective layer of steel mesh in bridge deck pavement according to the present invention includes the following steps:

[0034] (1) Prepare the steel reinforcement protective layer elevation trolley 1, support base 7, and correction steel plate 13.

[0035] The rebar protective layer elevation trolley 1 includes a triangular truss spanning at least the length between the guardrails on both sides of the bridge deck, roller sets, baffles 9, and limiting markers 4. The triangular truss consists of three metal rods 11 arranged in a triangle, with each metal rod fixed to the others by several diagonally distributed reinforcing rods 12 at intervals. The metal rods can be 4cm square alloy aluminum rods or steel pipe rods. The reinforcing rods 12 are alloy aluminum rods to reduce their own weight and prevent the middle of the truss from sagging. Roller sets for moving the triangular truss are provided on both sides of the bottom of the triangular truss. The upper surface of the wheel plate of each roller set is connected to the bottom two sides of the triangular truss. Wheel seats 2 are provided at the four corners of the lower end surface of the wheel plate of the roller set. Rollers 3 are axially connected to wheel seats 2 via shafts 6. The wheel surface of roller 3 is concave to facilitate movement along the channel steel rail. The roller 3 runs perpendicular to the axis of the bottom surface of the triangular truss. The upper edges of several baffles 9, which are distributed at intervals of 1m, are connected to one side of the bottom edge of the triangular truss by hinges 5, or the upper edges of several baffles distributed at intervals are connected to one side of the bottom edge of the triangular truss by adjusting steel wire ropes. The height of each baffle is the same. Each baffle near the upper edge of the baffle has a through hole at the same size position. When the adjusting steel wire rope passes through the through hole and is wrapped around the corresponding bottom edge of the triangular truss, it can facilitate the downward movement of the baffle and the limit rod. The baffle is made of 1mm thick steel plate. Each baffle has a limit rod 4 on its lower edge. When using it, it should be ensured that each limit rod 4 is on the same straight line.

[0036] The support base 7 is a cement or cast iron base with a width of 20-30cm, a length of 40cm, and a height of 40cm, used to support the channel steel 10, which serves as the track for the trolley that protects the steel reinforcement layer.

[0037] The correction steel sheet 13 is a steel sheet with a width of 5-10cm, a length of 15-20cm, and a thickness of 1-2mm, used to correct the levelness of the channel steel 10.

[0038] (2) Clean the bridge deck before laying the steel mesh. Cleaning the bridge deck includes first chiseling away the loose concrete with floating slurry on the lower end of the bridge slab 8 to be laid and at the base of the bridge deck railing, roughening the surface of the precast beam or cast-in-place bridge slab, and then using an air compressor and manual water spraying to thoroughly clean the bridge slab 8, ensuring that there is no dust or loose concrete with floating slurry.

[0039] (3) A support base 7 is set every 2m along the base of the bridge deck guardrail on both sides. A channel steel with a length of 11 to 20m is set on the upper surface of the support base on the same side. The channel steel is 20 to 30cm wide. By setting a correction steel plate between the upper end of the support base and the lower end of the channel steel, the upper end of the channel steel on both sides is corrected to be on the same horizontal plane.

[0040] (4) Install the steel reinforcement protective layer elevation trolley 1 on both sides of the upper end of the channel steel. The roller groups at the lower ends of the support trolley truss are located on the upper ends of the channel steel on both sides. After manually moving the elevation trolley back and forth so that it can run along the upper ends of the channel steel on both sides, connect the upper edge of several baffles set at intervals of 1m to one side of the bottom edge of the trolley truss through adjusting steel wire ropes. The height of each baffle is the same and the length of each adjusting steel wire is the same. Each baffle near the upper edge of the baffle is provided with a through hole at the same size position. When the adjusting steel wire rope passes through the through hole and is wrapped around the bottom edge of the corresponding triangular truss, it can facilitate the downward movement distance of the baffle and the limiting rod, so as to ensure that the limiting rod at the lower end of the baffle is on the same straight line. The lower end of each limiting rod on the same straight line is consistent with the design control elevation of the top surface of the steel mesh 15.

[0041] The method for ensuring that the lower ends of all limit markers on the same straight line are aligned with the design control elevation of the top surface of the reinforcing mesh 15 is as follows: (a) According to the designed elevation requirements of the protective concrete bridge deck layer, use a laser marker to mark the top surface line of the protective concrete bridge deck layer to be constructed on both sides of the bridge deck guardrail, and mark it with chalk as the control line for pouring the top surface of the protective concrete bridge deck layer. (b) Subtract the designed thickness of the protective layer of the top surface of the reinforcing mesh from the lower end of the control line, and mark the control line of the top surface of the reinforcing mesh with red chalk, and then verify it with a laser marker. (c) Adjust the lower ends of all limit markers on the reinforcing concrete protective layer elevation trolley to be on the same horizontal straight line, and on the same horizontal plane as the control line of the top surface of the reinforcing mesh marked with red chalk.

[0042] (5) Laying of steel mesh 15: The steel mesh is laid on the top surface of the bridge slab 8 according to the design requirements. The top surface of the steel mesh is adjusted and controlled to be consistent with the design control elevation according to each limit marker, including the adjustment and control of the existing support bars and the adjustment and control of the pre-embedded support bars.

[0043] (a) If no pre-embedded support bars are provided on the bridge deck 8, then support bars 14 need to be provided on the steel mesh. The adjustment and control of the existing support bars are as follows: the existing support bars are T-shaped, that is, a horizontal steel bar of the same diameter is fixed at the upper end of the φ6~8mm vertical steel bar. The horizontal steel bar is welded or tied to the steel mesh to ensure stable support. On the top surface of the bridge deck at the lower end of the laid steel mesh, each existing support bar to be installed is marked according to the design requirements. Four support bar points are set at intervals at the lower end of each square meter of steel mesh. The steel protective layer elevation trolley is manually moved to the upper space of the steel mesh at each existing support bar point in the transverse direction of the bridge deck, so that the lower end of each limit marker on the same straight line and each existing support bar point in the transverse direction are on the same vertical plane. The elevation trolley is then fixed. The steel mesh is manually pried up using a crowbar until its upper surface is aligned with the lower surface of each limit marker on the trolley. Support ribs 14 are then welded to the lower end of the aligned steel mesh. The lower end of the support ribs 14 rests against the corresponding marked support rib installation point, and the upper end of the support ribs is welded to the corresponding lower end of the steel mesh. Support ribs 14 of different lengths are welded to different locations to ensure that the top surface of the steel mesh is consistent with the design control elevation. This ensures that the thickness of the protective layer above the steel mesh is consistent and meets design and specification requirements when concrete is poured on the steel mesh later.

[0044] After the horizontal row adjustment and control welding support bars are completed, the upper end face of the horizontal steel mesh is aligned with the lower end face of each limit marker in the same straight line. Move the elevation trolley to the adjacent horizontal row where the support bars are to be installed. Repeat the adjustment and control welding support bar operation until the adjustment and control welding support bars of this channel steel section are completed.

[0045] (b) If embedded support bars are installed on bridge deck 8, the adjustment and control of the embedded support bars shall be as follows: The steel reinforcement protective layer elevation trolley shall be manually moved to the upper space of the steel mesh of the transverse embedded support bars of the bridge deck, so that the lower end face of each limit marker on the same straight line is on the same vertical plane as each transverse embedded support bar. The elevation trolley shall be fixed, and the steel mesh 15 shall be manually pried up using a pry bar until the upper end face of the steel mesh is aligned with the lower end face of each limit marker on the trolley. Then, the embedded support bars at the lower end of the aligned steel mesh shall be adjusted and corrected using a pry bar or hammer. The pre-embedded support bars at the lower end of the aligned steel mesh are raised by using a crowbar to raise the pre-embedded support bars that are lower than the design control elevation of the steel mesh, or lowered by using a hammer to knock down the pre-embedded support bars that are higher than the design control elevation of the steel mesh. The upper end of the pre-embedded support bars that have been corrected and aligned is then welded to the corresponding lower end of the steel mesh. The pre-embedded support bars are corrected and adjusted according to different locations to ensure that the top surface of the steel mesh is consistent with the design control elevation. This ensures that the thickness of the protective layer of the upper steel reinforcement of the steel mesh is consistent and meets the design and specification requirements when concrete is poured on the steel mesh in the subsequent process.

[0046] After the peers have finished adjusting and controlling the embedded support bars for welding, the upper surface of the transverse steel mesh is aligned with the lower surface of each limit marker on the same straight line. Move the elevation trolley to each embedded support bar in the adjacent row and repeat the operation of adjusting and controlling the embedded support bars for welding until the adjustment and control of the embedded support bars for welding in this channel steel section is completed.

[0047] (6) Repeat step (3) to extend the forward channel steel rail, so that the moving elevation trolley moves to the adjacent adjustment control steel mesh top surface is consistent with the design control elevation. Repeat step (5), and use the cyclic method of removing the old and replacing the new forward channel steel rail to move the elevation trolley forward until the steel mesh is laid.

[0048] (7) Repair the steel mesh at the dismantled support base area so that the repaired steel mesh is at the same height as the steel mesh laid according to the design requirements.

[0049] Repairing the steel mesh at the dismantled support base involves overlapping the longitudinal and transverse steel bars at both ends with the corresponding longitudinal and transverse steel mesh bars of the adjacent area by a staggered length of 20cm. The two steel bars at the overlap are tightly wrapped with wire, and the two steel bars are laterally overlapped side by side. The steel mesh at the repair site is on the same plane as the adjacent steel mesh.

[0050] Then, the concrete bridge deck layer is poured to the top control line of the protective concrete bridge deck layer on the steel mesh segments laid on the bridge deck. Since the steel mesh has been laid on the top surface of the bridge deck 8 according to the design requirements, and the top surface of the steel mesh has been adjusted and controlled to be consistent with the design control elevation according to each limit marker, the thickness of the top protective layer of the steel mesh on the bridge deck can be effectively guaranteed to be consistent. The pouring of the concrete bridge deck layer on the steel mesh segments is a traditional technique, so it will not be described in detail.

[0051] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for controlling the protective layer on the top surface of steel mesh reinforcement in bridge deck paving, characterized in that, Includes the following steps: (1) Prepare the rebar protective layer elevation trolley, support base, and correction steel plate; (2) Clean the bridge surface before laying the steel mesh; (3) Support bases are set at intervals along the base of the bridge deck guardrails on both sides. A channel steel with a length of 11 to 20 m and a width of 20 to 30 cm is set on the upper surface of the support base on the same side. By setting a correction steel plate between the upper end of the support base and the lower end of the channel steel, the upper end surfaces of the channel steel on both sides are corrected to be on the same horizontal plane. (4) Install a steel reinforcement protective layer elevation trolley on both sides of the upper end of the channel steel. The roller groups at the lower ends of the truss supporting the trolley are located on the upper ends of the channel steel on both sides. After manually moving the elevation trolley back and forth so that it can run along the upper ends of the channel steel on both sides, the upper edge of several baffles set at intervals is hinged to one side of the bottom edge of the trolley truss. The limit markers at the lower ends of the baffles are on the same straight line. The lower ends of each limit marker on the same straight line are consistent with the design control elevation of the top surface of the steel mesh. (5) Laying of steel mesh: The steel mesh is laid on the top surface of the bridge deck according to the design requirements. The top surface of the steel mesh is adjusted and controlled to be consistent with the design control elevation based on each limit marker, including the adjustment and control of the existing support bars and the adjustment and control of the pre-embedded support bars. (a) Adjustment and control of existing support reinforcement: On the top surface of the bridge slab at the lower end of the laid steel mesh, mark the points of each existing support reinforcement to be installed according to the design requirements. Set four support reinforcement points at intervals per square meter. Manually move the steel reinforcement protective layer elevation trolley to the upper space of the steel mesh at each existing support reinforcement point in the transverse direction of the bridge slab, so that the lower end of each limit marker on the same straight line is on the same vertical plane as each existing support reinforcement point in the transverse direction. Fix the elevation trolley, and manually use a pry bar to lift the steel mesh so that the steel mesh... When the upper end face is aligned with the lower end face of each limit bar on the trolley, a support bar is welded to the lower end of the aligned steel mesh. The lower end of the support bar is supported at the corresponding marked installation support bar point. The upper end of the support bar is welded to the lower end of the corresponding steel mesh. Support bars of different lengths are welded according to different parts to ensure that the top surface of the steel mesh is consistent with the design control elevation, thereby ensuring that the thickness of the steel mesh upper steel reinforcement protective layer is consistent and meets the design and specification requirements when concrete is poured on the steel mesh in the subsequent process. After the horizontal row adjustment and control welding support bar is completed, the upper end face of the horizontal steel mesh is aligned with the lower end face of each limit bar in the same straight line. Move the elevation trolley to the adjacent horizontal row where the support bar is to be installed. Repeat the adjustment and control welding support bar operation until the adjustment and control welding support bar of this channel steel section is completed. (b) Adjustment and control of embedded support bars: The steel reinforcement protective layer elevation trolley is manually moved to the upper space of the steel mesh of the transverse embedded support bars of the bridge slab, so that the lower end face of each limit marker on the same straight line is on the same vertical plane as each transverse embedded support bar. The elevation trolley is fixed, and the steel mesh is manually pried up with a crowbar so that the upper end face of the steel mesh is aligned with the lower end face of each limit marker on the trolley. Then, the embedded support bars at the lower end of the aligned steel mesh are corrected and adjusted with a crowbar or hammer so that the upper end of the corrected and aligned embedded support bars is welded to the corresponding lower end of the steel mesh. The embedded support bars are corrected and adjusted according to different parts to ensure that the top surface of the steel mesh is consistent with the design control elevation, thereby ensuring that the thickness of the steel reinforcement protective layer on the upper part of the steel mesh is consistent and meets the design and specification requirements when concrete is poured on the steel mesh in the subsequent process. After the peers have finished adjusting and controlling the embedded support bars for welding, the upper surface of the transverse steel mesh is aligned with the lower surface of each limit marker in the same straight line. Move the elevation trolley to each embedded support bar in the adjacent row and repeat the operation of adjusting and controlling the embedded support bars for welding until the adjustment and control of the embedded support bars for welding in this channel steel section is completed. (6) Repeat step (3) to extend the forward channel steel rail, so that the moving elevation trolley moves to the working section where the top surface of the adjacent adjustment control steel mesh is consistent with the design control elevation. Repeat step (5), and use the cyclic method of removing the old and replacing the new forward channel steel rail to move the elevation trolley forward until the steel mesh is laid. (7) Repair the steel mesh at the dismantled support base area so that the repaired steel mesh is at the same height as the steel mesh laid according to the design requirements.

2. The control method according to claim 1, characterized in that: The method for ensuring that the lower end of each limiting marker on the same straight line is consistent with the design control elevation of the top surface of the steel mesh is as follows: (a) According to the design requirements for the elevation of the protective concrete bridge deck, use a laser marker to mark the top line of the protective concrete bridge deck to be constructed on the lower part of the bridge deck guardrail on both sides of the protective concrete bridge deck to be constructed, and mark it with chalk as the control line for pouring the top of the protective concrete bridge deck. (b) Subtract the designed thickness of the protective layer on the top surface of the steel mesh from the lower end of the control line, mark the control line on the top surface of the steel mesh with red chalk, and then verify it with a laser marking instrument; (c) Adjust the lower ends of each limit marker on the rebar cover elevation trolley to be on the same horizontal straight line and on the same horizontal plane as the control line of the top surface of the rebar mesh marked with red chalk.

3. The control method according to claim 1, characterized in that: The aforementioned method of adjusting and aligning the pre-embedded support bars at the lower end of the steel mesh by using a crowbar or hammer includes raising the pre-embedded support bars that are lower than the design control elevation of the steel mesh by using a crowbar, or lowering the pre-embedded support bars that are higher than the design control elevation of the steel mesh by using a hammer.

4. The control method according to claim 1, characterized in that: The existing support bar is T-shaped, with a horizontal bar fixed to the upper end of the vertical bar, and the horizontal bar is welded to the steel mesh.

5. The control method according to claim 1, characterized in that: The repair of the steel mesh at the dismantled support base is described as follows: the longitudinal and transverse steel bars at both ends of the repair are overlapped with the corresponding longitudinal and transverse steel bars of the adjacent steel mesh by a staggered length of 20cm, and the two steel bars at the overlap are tightly wrapped with wire. The two steel bars are overlapped side by side, and the steel mesh at the repair site is on the same plane as the adjacent steel mesh.

6. The control method according to claim 1, characterized in that: The aforementioned rebar protective layer elevation trolley includes a triangular truss spanning at least the length between the guardrails on both sides of the bridge deck, roller sets, baffles, and limiting rods. The triangular truss consists of three metal rods arranged in a triangle, with each metal rod fixed to the other by several diagonally distributed reinforcing rods at intervals. Roller sets for moving the triangular truss are provided on the bottom two sides of the triangular truss. The upper surface of the wheel plate of each roller set is connected to the bottom two sides of the triangular truss. Wheel seats are provided at the four corners of the lower end of the wheel plate of the roller set. The rollers are axled to the wheel seats, and the running direction of the rollers is perpendicular to the axis of the bottom surface of the triangular truss. The upper surface of several baffles distributed at intervals is connected to one side of the bottom edge of the triangular truss by hinges, or the upper surface of several baffles distributed at intervals is connected to one side of the bottom edge of the triangular truss by adjusting steel wire ropes. Limiting rods are provided on the lower end of each baffle, and all limiting rods are on the same straight line.

7. The control method according to claim 6, characterized in that: All the baffles are of the same height, and each baffle has a through hole at the same size position near the upper edge of the baffle.

8. The control method according to claim 6, characterized in that: The metal rod is an alloy aluminum rod or a steel pipe rod.

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