Underwater bridge pier repairing and reinforcing device based on FRP grid and construction method of underwater bridge pier repairing and reinforcing device

Abstract

The invention discloses an underwater bridge pier repairing and reinforcing device based on an FRP grid and a construction method thereof, and relates to the technical field of bridge pier repairing, the underwater bridge pier repairing and reinforcing device comprises a bridge pier, the bridge pier comprises a bearing platform and a pier body, the outer side of the pier body is wound with the FRP grid, the outer side of the FRP grid is covered with a sleeve, and a plurality of limiting blocks are arranged on nodes of the FRP grid at intervals; the limiting block comprises an inner box and an outer box which are connected in an inserted mode, the inner box and the outer box make contact with the pier body and the sleeve respectively, and a self-adjusting mechanism is arranged in the limiting block. The FRP grids, the limiting blocks, the self-adjusting mechanism and the like are arranged, the advantages that the FRP grids are high in node rigidity, longitudinal grids and transverse grids are cooperatively stressed and the like are utilized, the characteristics of underwater anti-dispersion mortar are matched, drainage-free enclosure grouting can be achieved, and the construction period is shortened; and moreover, the self-adaptive adjusting mechanism in the limiting block can also realize stepless adjustment of the thickness of the limiting block, so that deformation of part of the limiting block due to strong extrusion of the sleeve is avoided, and the problem that a gap or a cavity appears between the limiting block and the mortar layer is reduced.

Description

Technical Field

[0001] This invention relates to the field of bridge pier repair technology, and in particular to an underwater bridge pier repair and reinforcement device based on FRP grid and its construction method. Background Technology

[0002] The reinforcement and repair of corroded bridge piers and pile foundations often requires processes such as cofferdam drainage, formwork support, and concrete pouring, which presents problems such as high construction costs, long construction periods, and disruption to sea lanes. Furthermore, traditional reinforcement methods, such as increasing the cross-section, use reinforced concrete layers that are no different from the original structure, making them prone to secondary corrosion.

[0003] Chinese patent application number CN202110238313.0 discloses a complete method for rapidly reinforcing earthquake-damaged bridge piers using an external steel sleeve. This invention employs a simple external steel sleeve reinforcement process, where the external steel sleeve acts as a template, allowing for direct grouting between the steel sleeve and the pier using early-strength self-compacting grout. This simplifies the construction process while achieving rapid reinforcement.

[0004] Chinese patent application number CN202510334098.2 discloses a method for reinforcing bridge piers using steel sleeves. Compared with the traditional steel pipe sleeve reinforcement method, this invention reserves a certain unreinforced area at the upper and lower ends of the original bridge pier, thus preserving the interface properties between the original bridge pier and the cap beam and abutment. This facilitates the pouring of concrete while reducing the impact on the internal stress distribution at the interface of the components.

[0005] In the early stages of bridge pier repair, it is necessary to remove loose stones from the surface of the bridge pier and make the surface as flat as possible. However, during actual chiseling, the impact force of chiseling tools such as pneumatic picks and high-pressure water guns is difficult to control evenly, and pits or grooves of varying depths are likely to appear on the concrete surface. Furthermore, long-term water flow impact will enlarge the honeycomb pores inside the concrete, and after chiseling, it will also cause wavy undulations or local peeling.

[0006] However, the thickness of the limiting block is currently fixed. Therefore, when the limiting block is used in conjunction with the pier surface and the sleeve, some of the limiting block will inevitably be located on the protruding part of the pier surface. This causes some of the limiting block to be subjected to strong compression from the sleeve. When the sleeve is removed, the stress release inside the limiting block will cause gaps or voids to form between the limiting block and the mortar, making the area more susceptible to corrosion. Furthermore, due to the deformation of the limiting block under compression, its resistance to water flow impact is weakened, making it difficult for the limiting block to withstand long-term water flow impact.

[0007] In addition, the core function of the limiting block is to form a uniform grout layer, enabling the FRP mesh and concrete to deform in tandem. However, in actual construction, the position of the FRP mesh is prone to deviation. If the FRP mesh is too close to the pier surface, the grout layer thickness on that side will be insufficient, resulting in uneven load transfer and stress concentration at the mesh nodes, which can easily lead to concrete surface crushing or localized FRP mesh breakage. If the FRP mesh is too close to the sleeve, the mortar content on the side closest to the sleeve will be less. After the sleeve is removed, a weak zone will form on the outer side of the FRP mesh. External loads (such as water flow impact or vibration) will act directly on this weak zone, easily causing the grout layer on that side to peel off and exposing the FRP mesh directly underwater, thereby reducing the service life of the reinforcement layer.

[0008] To address these issues, this invention proposes an underwater bridge pier repair and reinforcement device based on FRP grids and its construction method. Summary of the Invention

[0009] The purpose of this invention is to provide an underwater bridge pier repair and reinforcement device based on FRP grid and its construction method, so as to solve the technical problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: an underwater bridge pier repair and reinforcement device and its construction method based on FRP mesh, comprising a bridge pier, the bridge pier including a pier cap and a pier body, the outer side of the pier body being wrapped with FRP mesh, the outer side of the FRP mesh being covered with a sleeve, and multiple limiting blocks being spaced apart on the nodes of the FRP mesh, the limiting block including two interlocking inner boxes and outer boxes, the inner boxes and outer boxes respectively contacting the pier body and the sleeve; The limiting block is equipped with a self-adjusting mechanism. When the sleeve squeezes the limiting block during installation, the self-adjusting mechanism enables the limiting block to adaptively adjust its thickness according to the unevenness of the pier surface.

[0011] Preferably, the outer and inner boxes are provided with a plurality of cooperating through slots, which are used to accommodate the cross nodes of the FRP mesh, and the length of the through slots is greater than the thickness of the nodes.

[0012] Preferably, the self-adjusting mechanism includes a rotating cylinder rotatably connected to the outer box, a fixed rod matching the rotating cylinder fixedly connected inside the inner box, a spiral track being provided on the circumferential side of the fixed rod, and a connecting block matching the spiral track being fixedly connected to the inner wall of the rotating cylinder. When the rotating cylinder moves along the axial direction of the fixed rod, the spiral track and the connecting block drive the rotating cylinder to rotate.

[0013] Preferably, both the inner and outer boxes have support members on their inner walls that contact the FRP mesh nodes. The circumferential sides of the support members are respectively provided with linkage members that connect to the rotating cylinder and the fixed rod. When the inner and outer boxes approach each other, the linkage members can keep the amount of movement of the inner and outer boxes consistent.

[0014] Preferably, the support includes a connecting column that is fixedly connected to the inner wall of the inner box and the outer box respectively, a support cap that is slidably connected to the outer side of the connecting column, two support caps that contact the inner and outer sides of the FRP mesh node respectively, and an elastic element is provided between each support cap and the connecting column.

[0015] Preferably, the linkage includes a connecting ring fixedly connected to the circumferential side of the support cap, a first movable ring threadedly connected to the circumferential side of the rotating cylinder, a first connecting plate fixedly connected between the first movable ring and the adjacent connecting ring, a second movable ring slidably connected to the fixed rod, a second connecting plate provided between the second movable ring and the adjacent connecting ring, the second connecting plate and the second movable ring being rotatably connected, and the second connecting plate and the connecting ring being fixedly connected, one end of the rotating cylinder contacting the second movable plate, and a locking mechanism provided between the end of the rotating cylinder and the second movable plate, the locking mechanism locking the second movable plate and the end of the rotating cylinder.

[0016] Preferably, the locking mechanism includes a wedge-shaped groove formed on the side of the second movable ring near the rotating drum, and a wedge-shaped block that matches the wedge-shaped groove is fixedly connected to the end of the rotating drum.

[0017] Preferably, the FRP mesh is a composite material mesh prepared by impregnating carbon fiber, basalt fiber, glass fiber, or two or more fiber bundles with resin and then performing a pultrusion molding process.

[0018] Preferably, a sealing gasket is coaxially disposed at the bottom of the sleeve, the upper surface of the sealing gasket is provided with a plurality of circumferentially distributed protrusions, the bottom of the sleeve is provided with a plurality of slots matching the protrusions, and a steel ring is fixedly connected to the outer side of the sleeve.

[0019] A method for repairing and reinforcing underwater bridge piers includes the following steps: Step 1: Clean the surface impurities of the foundation and pier body, and roughen and level them; Step 2: Prepare underwater anti-dispersion mortar; Step 3: Cut FRP mesh of appropriate size according to the pier dimensions and the required number of mesh layers; Step 4: After setting limiters at intervals along the nodes of the FRP mesh in both the circumferential and longitudinal directions, wrap and fix the FRP mesh along the pier body; Step 5: Drill multiple holes on the pier cap that are coaxial with the pier body, and make sure that the spacing between the holes is consistent with the spacing of the FRP mesh. Insert the bottom of the FRP mesh into the holes. Step 6: Place the sealing gasket on the bearing platform, apply the release agent to the inside of the sleeve, install the sleeve on top of the sealing gasket, and tighten it with a steel ring in the circumferential direction. Step 7: Inject the prepared underwater anti-dispersion mortar between the casing and the bridge pier using a pump and conduit; Step 8: Once the underwater anti-dispersion mortar has reached the required curing time, remove and recycle the casing.

[0020] The beneficial effects of this invention are: This invention utilizes FRP mesh, sleeves, limiting blocks, and a self-adjusting mechanism. It leverages the advantages of FRP mesh, such as high node stiffness, coordinated force distribution between longitudinal and transverse meshes, light weight, and convenient installation. Combined with the properties of underwater anti-dispersion mortar, it enables drainage-free grouting, shortening the construction period and reducing construction costs. Furthermore, the adaptive adjustment mechanism inside the limiting blocks allows for stepless adjustment of the block thickness, preventing deformation caused by the strong pressure from the sleeve when some limiting blocks are located on protruding parts of the pier surface. This reduces or even eliminates gaps or voids between the limiting blocks and the mortar layer. Additionally, the locking mechanism and the threaded engagement between the first movable ring and the rotating cylinder overcome the elastic potential energy of the FRP mesh, ensuring that the distance between the FRP mesh and the pier body and sleeve remains consistent. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the underwater bridge pier repair and reinforcement device based on FRP grid according to the present invention.

[0022] Figure 2 This is a schematic diagram showing the interaction between the FRP mesh of the present invention and the pump.

[0023] Figure 3 This is a schematic diagram of the cross-sectional structure of the FRP mesh and the bridge pier of the present invention.

[0024] Figure 4 This is a schematic diagram of the installation of the limiting block and the FRP mesh node of the present invention.

[0025] Figure 5 This is a cross-sectional schematic diagram of the limiting block and FRP mesh structure of the present invention.

[0026] Figure 6 This is a three-dimensional cross-sectional view of the limiting block of the present invention.

[0027] Figure 7 This is a schematic diagram showing the cooperation between the self-adjusting mechanism and the linkage component of the present invention.

[0028] Figure 8This is a schematic diagram of the locking mechanism of the present invention.

[0029] Figure 9 This is a schematic diagram showing the fit between the limiting block of the present invention and the concave and convex surfaces of the bridge pier.

[0030] Figure 10 This is a schematic diagram of the sleeve and sealing gasket of the present invention.

[0031] The attached figures are labeled as follows: 1. Pier; 11. Pier cap; 12. Pier body; 2. FRP mesh; 3. Sleeve; 31. Slot; 4. Limiting block; 41. Inner box; 42. Outer box; 43. Through groove; 5. Self-adjusting mechanism; 51. Rotary drum; 52. Fixed rod; 53. Spiral track; 54. Support component; 541. Connecting column; 542. Support cap; 55. Linkage component; 551. Connecting ring; 552. First movable ring; 553. First connecting plate; 554. Second movable ring; 555. Second connecting plate; 6. Locking mechanism; 61. Wedge groove; 62. Wedge block; 7. Sealing gasket; 71. Protrusion. 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. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1 In actual construction, the impact force of chiseling tools is difficult to control evenly, easily forming pits or grooves of varying depths on the concrete surface. Furthermore, long-term water flow impact can enlarge the honeycomb pores inside the concrete, resulting in wavy undulations or localized spalling after chiseling. However, the thickness of the limiting blocks is currently fixed. Therefore, when the limiting blocks are used in conjunction with the pier surface and the sleeve, some of the limiting blocks inevitably end up on the protruding parts of the pier surface, causing some of the limiting blocks to be subjected to strong pressure from the sleeve. When the sleeve is removed, the stress release inside the limiting block leads to gaps or voids between the limiting block and the mortar, making that area more susceptible to corrosion. This embodiment is invented to solve the above problems.

[0034] Please see Figures 1 to 10As shown, an embodiment of the present invention provides an underwater bridge pier repair and reinforcement device based on FRP mesh, comprising a bridge pier 1, the bridge pier 1 including a pier cap 11 and a pier body 12, the outer side of the pier body 12 being wrapped with an FRP mesh 2, the mesh spacing being 50mm or 100mm, etc., the outer side of the FRP mesh 2 being covered with a sleeve 3, and multiple limiting blocks 4 being spaced apart on the nodes of the FRP mesh 2, the limiting block 4 including two interlocking inner boxes 41 and outer boxes 42, the inner boxes 41 and outer boxes 42 respectively contacting the pier body 12 and the sleeve 3.

[0035] The limiting block 4 is equipped with a self-adjusting mechanism 5. When the sleeve 3 squeezes the limiting block 4 during installation, the self-adjusting mechanism 5 can make the limiting block 4 adaptively adjust its thickness according to the unevenness of the surface of the pier body 12.

[0036] FRP mesh 2 is a composite material mesh made by impregnating carbon fiber, basalt fiber, glass fiber or two or more fiber bundles with resin and then pultruding it. The circumferential overlap length of FRP mesh 2 around the pier body 12 is not less than 5 times the mesh spacing, that is, the overlap edge of FRP mesh 2 is not less than 5 times the mesh spacing, and steel wire is used to tie and fix the overlapping parts of the multi-layer mesh nodes.

[0037] Please see Figure 10 As shown, a sealing gasket 7 is coaxially arranged below the sleeve 3. The upper surface of the sealing gasket 7 is provided with multiple circumferentially distributed protrusions 71. The bottom of the sleeve 3 is provided with multiple slots 31 that match the protrusions 71. A steel ring is fixedly connected to the outside of the sleeve 3. The steel ring is composed of two half rings and is connected with high-strength bolts.

[0038] Please see Figure 5 and Figure 6 As shown, the outer box 42 and the inner box 41 are provided with a number of mutually cooperating through slots 43. The through slots 43 are used to accommodate the cross nodes of the FRP grid 2, and the length of the through slots 43 is greater than the thickness of the nodes. When the pumping machine pumps the underwater anti-dispersion mortar into the space between the sleeve 3 and the pier body 12, the mortar can enter the interior of the limiting block 4 from the through slots 43, thereby improving the support strength at the nodes of the FRP grid 2.

[0039] Please see Figures 5 to 7As shown, the self-adjusting mechanism 5 includes a rotating cylinder 51 rotatably connected to the outer box 42. A fixed rod 52 matching the rotating cylinder 51 is fixedly connected inside the inner box 41. A spiral track 53 is provided on the circumferential side of the fixed rod 52. A connecting block matching the spiral track 53 is fixedly connected to the inner wall of the rotating cylinder 51. When the rotating cylinder 51 moves along the axial direction of the fixed rod 52, the spiral track 53 and the connecting block drive the rotating cylinder 51 to rotate. An indicator plate is provided on one side of the rotating cylinder 51 that passes through the outer box 42. An initial mark is provided on the indicator plate. The indicator plate and the initial mark are used to indicate whether the initial position of the rotating cylinder 51 has changed, so as to avoid the problem of blockage or even jamming when the rotating cylinder 51 and the fixed rod 52 are engaged. If the rotating cylinder 51 rotates before the outer box 42 is installed with the inner box 41, the worker can reset it by rotating the indicator plate.

[0040] When in use, the limiting blocks 4 are first installed at intervals at the nodes of the FRP mesh 2. During installation, the FRP mesh 2 is first placed between the inner box 41 and the outer box 42, so that the inner box 41 and the outer box 42 are close to each other. At this time, the rotating cylinder 51 and the fixing rod 52 are inserted into each other and form a rotational fit. At this time, the FRP mesh 2 is located in the through groove 43 of the outer box 42 and the inner box 41.

[0041] It should be noted that the initial thickness of the limiting block 4 is the largest. After the FRP mesh 2 is wrapped around the surface of the pier body 12, the inner box 41 of the limiting block 4 contacts the surface of the pier body 12. After the sleeve 3 is installed, the outer box 42 moves towards the inner box 41 after being squeezed by the sleeve 3. At this time, the rotating cylinder 51 rotates under the drive of the spiral track 53 and the connecting block, thereby realizing the stepless adjustment of the thickness of the limiting block 4.

[0042] In summary, by setting up FRP mesh 2, sleeve 3, limiting block 4 and self-adjusting mechanism 5, the FRP mesh 2 has high node stiffness, longitudinal and transverse meshes work together to bear force, light weight, convenient installation, and excellent durability. It can effectively prevent secondary corrosion of the reinforced pier 1. In addition, with the characteristics of underwater anti-dispersion mortar, drainage-free grouting can be achieved, shortening the construction period and reducing construction costs.

[0043] Furthermore, the limiting block 4 can not only limit the spacing between the inner and outer sides of the FRP grid 2, but its internal adaptive adjustment mechanism can also enable stepless adjustment of the thickness of the limiting block 4, so as to avoid the deformation caused by the strong squeezing of the sleeve 3 when some of the limiting blocks 4 are on the protrusion 71 part of the pier 1 surface, and reduce or even avoid the problem of gaps or voids between the limiting block 4 and the mortar layer.

[0044] Example 2 Furthermore, the core function of the limiting block 4 is to form a uniform grout layer, enabling the FRP mesh 2 to deform in tandem with the concrete. However, when the FRP mesh 2 is too close to the surface of the pier 1, the grout layer thickness on that side will be insufficient, resulting in uneven load distribution and stress concentration at the mesh nodes, which can easily lead to concrete surface crushing or localized fracture of the FRP mesh 2. Conversely, when the FRP mesh 2 is too close to the sleeve 3, the mortar content on the side closest to the sleeve 3 is lower. After removing the sleeve 3, a weak zone will form on the outer side of the FRP mesh 2, and external loads will act directly on this weak zone, easily causing the grout layer on that side to peel off and exposing the FRP mesh 2 directly underwater, thus reducing the service life of the reinforcement layer. Further improvements are made based on the above embodiments.

[0045] Please see Figures 5 to 9 As shown, both the inner box 41 and the outer box 42 are provided with support members 54 that contact the nodes of the FRP mesh 2. The circumferential sides of the support members 54 are respectively provided with linkage members 55 that are connected to the rotating cylinder 51 and the fixed rod 52. When the inner box 41 and the outer box 42 approach each other, the linkage members 55 can keep the movement of the inner box 41 and the outer box 42 consistent.

[0046] The support member 54 includes a connecting post 541 that is fixedly connected to the inner wall of the inner box 41 and the outer box 42 respectively. A support cap 542 is slidably connected to the outside of the connecting post 541. The two support caps 542 are in contact with the inner and outer sides of the FRP mesh 2 node respectively. An elastic element is provided between each support cap 542 and the connecting post 541.

[0047] Please see Figure 6 and Figure 7 As shown, the linkage 55 includes a connecting ring 551 fixedly connected to the circumferential side of the support cap 542, a first movable ring 552 threadedly connected to the circumferential side of the rotating cylinder 51, a first connecting plate 553 fixedly connected between the first movable ring 552 and the adjacent connecting ring 551, a second movable ring 554 slidably connected to the fixed rod 52, a second connecting plate 555 provided between the second movable ring 554 and the adjacent connecting ring 551, the second connecting plate 555 and the second movable ring 554 being rotatably connected, and the second connecting plate 555 and the connecting ring 551 being fixedly connected, one end of the rotating cylinder 51 contacting the second movable plate, and a locking mechanism 6 provided between the end of the rotating cylinder 51 and the second movable plate, the locking mechanism 6 locking the second movable plate and the end of the rotating cylinder 51.

[0048] Please see Figure 8 As shown, the locking mechanism 6 includes a wedge-shaped groove 61 opened on the side of the second movable ring 554 near the rotating cylinder 51, and a wedge-shaped block 62 that matches the wedge-shaped groove 61 is fixedly connected to the end of the rotating cylinder 51.

[0049] Based on the above embodiments, during use, when the outer box 42 is squeezed by the sleeve 3, the outer box 42 moves closer to the inner box 41. At this time, the rotating cylinder 51 moves along the axis of the fixed rod 52 and rotates under the action of the spiral track 53 and the connecting block. At this time, the end of the rotating cylinder 51 away from the outer box 42 contacts the second movable ring 554 and pushes the second movable ring 554 to move closer to the inner box 41. Meanwhile, during the rotation of the rotating cylinder 51, the first movable ring 552 moves closer to the outer box 42 under the action of the thread, and the moving distance of the first movable ring 552 and the second movable ring 554 is the same.

[0050] Furthermore, when the rotating drum 51 contacts the second movable ring 554, as the rotating drum 51 rotates, the wedge block 62 on the rotating drum 51 will be inserted into the wedge groove 61, thereby forming a locking fit.

[0051] The purpose of setting the locking mechanism 6 is as follows: After the sleeve 3 is completely fixed, since there are grooves or protrusions 71 on the surface of the pier body 12, although the distance between the FRP mesh 2 and the pier body 12 and the sleeve 3 can be kept consistent by the linkage 55, there will inevitably be elastic potential energy between two or more adjacent limit blocks 4, that is, the FRP mesh 2 has a tendency to reset to the side of the pier body 12 or the sleeve 3. If the FRP mesh 2 is not locked, the FRP mesh 2 will be too close to the pier body 12 or the sleeve 3.

[0052] The FRP mesh 2 is locked in the following ways: When the FRP mesh 2 tends to move closer to the pier body 12, and the wedge groove 61 on the second movable ring 554 and the wedge block 62 on the rotating cylinder 51 have already formed a locking engagement, the movement tendency of the FRP mesh 2 cannot cause the second movable ring 554 to drive the rotating cylinder 51 to move axially, that is, the support member 54 in the inner box 41 cannot move; when the FRP mesh 2 tends to move closer to the sleeve 3, since the first movable ring 552 and the rotating cylinder 51 are threadedly connected, when the FRP mesh 2 squeezes the support member 54 in the outer box 42, the first movable ring 552 and the rotating cylinder 51 form a threaded lock. The FRP mesh 2 is locked in the above two ways.

[0053] In summary, through the linkage 55, locking mechanism 6, and support 54, the limiting block 4 can not only adaptively adjust according to the distance between the surface of the pier body 12 and the sleeve 3, but also constrain the FRP mesh 2 during its adjustment process, so that the FRP mesh 2 is located in the middle position of the limiting block 4. Furthermore, through the locking mechanism 6 and the threaded engagement between the first movable ring 552 and the rotating cylinder 51, the elastic potential energy of the FRP mesh 2 is overcome, so that the distance between the FRP mesh 2 and the pier body 12 and the sleeve 3 remains consistent. This avoids problems such as the FRP mesh 2 being too close to the pier body 12, resulting in uneven load transmission, and being too close to the sleeve 3, resulting in an excessively thin mortar layer on that side.

[0054] Example 3 This embodiment also provides a method for repairing and reinforcing underwater bridge piers, including the following steps: Step 1: Clean the impurities on the surface of the foundation 11 and the pier body 12, and roughen and level them.

[0055] Step 2: Prepare underwater anti-dispersion mortar.

[0056] Step 3: Based on the dimensions of the pier body 12 and the required number of mesh layers, cut out an FRP mesh 2 of appropriate size.

[0057] Step 4: After setting limiters at intervals along the nodes of the FRP mesh 2 in both the circumferential and longitudinal directions, wrap and fix the FRP mesh 2 along the pier body 12.

[0058] Step 5: Drill multiple holes on the pier cap 11 that are coaxial with the pier body 12, and make the spacing between the holes consistent with the spacing of the FRP mesh 2. Insert the bottom of the FRP mesh 2 into the holes.

[0059] Step 6: Place the sealing gasket 7 on the bearing platform 11, apply the release agent to the inside of the sleeve 3, install the sleeve 3 above the sealing gasket 7, and tighten it with a steel ring in the circumferential direction.

[0060] Step 7: Inject the prepared underwater anti-dispersion mortar between the sleeve 3 and the pier 1 through a pump and a conduit.

[0061] Step 8: Once the underwater anti-dispersion mortar has reached the required curing time, remove and recycle casing 3.

[0062] In this embodiment, the underwater anti-dispersion mortar in step two consists of the following components: cement: 100 parts; water: 30-40 parts; sand: 50-100 parts; water-reducing agent: 1-2 parts; flocculant: 1-4 parts.

[0063] The cement is 32.5 or 42.5 ordinary Portland cement, the water is ordinary tap water, the sand is river sand, the water-reducing agent is polycarboxylate high-efficiency water-reducing agent, and the flocculant can be polyacrylamide or cellulose flocculant.

[0064] In step six, other release agents such as silicone resin-based, oil-based, and water-based polymer emulsion release agents can be used.

[0065] In step seven, when pumping underwater anti-dispersion mortar using a grouting machine, the duct of the grouting machine should be extended to the bottom of the pier body 12, and the duct opening should always be inside the mortar layer.

[0066] The above description is only 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. An underwater bridge pier repair and reinforcement device based on FRP grid, comprising a bridge pier (1), wherein the bridge pier (1) includes a pier cap (11) and a pier body (12), characterized in that, The outer side of the pier body (12) is wrapped with an FRP mesh (2), and the outer side of the FRP mesh (2) is covered with a sleeve (3). Multiple limiting blocks (4) are spaced apart on the nodes of the FRP mesh (2). The limiting block (4) includes two interlocking inner boxes (41) and outer boxes (42). The inner boxes (41) and outer boxes (42) are in contact with the pier body (12) and the sleeve (3) respectively. The limiting block (4) is provided with a self-adjusting mechanism (5). When the sleeve (3) squeezes the limiting block (4) during installation, the self-adjusting mechanism (5) enables the limiting block (4) to adaptively adjust the thickness of the limiting block (4) according to the unevenness of the surface of the pier body (12).

2. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 1, characterized in that, The outer box (42) and inner box (41) are provided with a plurality of mutually cooperating through slots (43), the through slots (43) are used to accommodate the cross nodes of the FRP mesh (2), and the length of the through slots (43) is greater than the thickness of the nodes.

3. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 2, characterized in that, The self-adjusting mechanism (5) includes a rotating cylinder (51) rotatably connected to the outer box (42). The inner box (41) is fixedly connected to a fixed rod (52) that matches the rotating cylinder (51). A spiral track (53) is provided on the circumferential side of the fixed rod (52). A connecting block that matches the spiral track (53) is fixedly connected to the inner wall of the rotating cylinder (51). When the rotating cylinder (51) moves along the axial direction of the fixed rod (52), the spiral track (53) and the connecting block drive the rotating cylinder (51) to rotate.

4. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 3, characterized in that, The inner wall of both the inner box (41) and the outer box (42) is provided with a support member (54) that contacts the nodes of the FRP mesh (2). The circumferential side of the support member (54) is provided with a linkage member (55) that connects to the rotating cylinder (51) and the fixed rod (52). When the inner box (41) and the outer box (42) approach each other, the linkage member (55) can keep the amount of movement of the inner box (41) and the outer box (42) consistent.

5. The underwater bridge pier repair and reinforcement device and its construction method based on FRP mesh according to claim 4, characterized in that, The support member (54) includes a connecting column (541) that is fixedly connected to the inner wall of the inner box (41) and the outer box (42) respectively. A support cap (542) is slidably connected to the outside of the connecting column (541). The two support caps (542) are in contact with the inner and outer sides of the FRP mesh (2) nodes respectively. An elastic element is provided between each support cap (542) and the connecting column (541).

6. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 5, characterized in that, The linkage (55) includes a connecting ring (551) fixedly connected to the circumferential side of the support cap (542). The circumferential side of the rotating cylinder (51) is threaded with a first movable ring (552). A first connecting plate (553) is fixedly connected between the first movable ring (552) and the adjacent connecting ring (551). A second movable ring (554) is slidably connected on the fixed rod (52). A second connecting plate (555) is provided between the second movable ring (554) and the adjacent connecting ring (551). The second connecting plate (555) and the second movable ring (554) are rotatably connected, and the second connecting plate (555) and the connecting ring (551) are fixedly connected. One end of the rotating cylinder (51) is in contact with the second movable plate, and a locking mechanism (6) is provided between the end of the rotating cylinder (51) and the second movable plate. The locking mechanism (6) locks the second movable plate and the end of the rotating cylinder (51).

7. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 6, characterized in that, The locking mechanism (6) includes a wedge groove (61) opened on the side of the second movable ring (554) near the rotating cylinder (51), and a wedge block (62) matching the wedge groove (61) is fixedly connected to the end of the rotating cylinder (51).

8. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 7, characterized in that, The FRP mesh (2) is a composite material mesh made by impregnating carbon fiber, basalt fiber, glass fiber or two or more fiber bundles with resin and then pultruding it.

9. The underwater bridge pier repair and reinforcement device based on FRP mesh according to claim 8, characterized in that, A sealing gasket (7) is coaxially arranged below the sleeve (3). The upper surface of the sealing gasket (7) is provided with multiple circumferentially distributed protrusions (71). The bottom of the sleeve (3) is provided with multiple slots (31) that match the protrusions (71). A steel ring is fixedly connected to the outside of the sleeve (3).

10. A method for repairing and reinforcing underwater bridge piers, employing the FRP-based underwater bridge pier repair and reinforcement device as described in claims 1-9, characterized in that... Includes the following steps: Step 1: Clean the surface impurities of the foundation (11) and the pier body (12), and roughen and level them; Step 2: Prepare underwater anti-dispersion mortar; Step 3: Cut out an appropriate size FRP grid (2) according to the dimensions of the pier body (12) and the required number of grid layers; Step 4: After setting limiters at intervals at the nodes along the circumferential and longitudinal directions of the FRP mesh (2), wrap and fix the FRP mesh (2) along the pier body (12); Step 5: Drill multiple holes on the pier cap (11) that are coaxial with the pier body (12), and make the spacing between the holes consistent with the spacing of the FRP mesh (2). Insert the bottom of the FRP mesh (2) into the holes. Step 6: Place the sealing gasket (7) on the bearing platform (11), apply the release agent to the inside of the sleeve (3), install the sleeve (3) above the sealing gasket (7) and tighten it with a steel ring in the circumferential direction; Step 7: Inject the prepared underwater anti-dispersion mortar between the casing (3) and the pier (1) through a pump and conduit; Step 8: Once the underwater anti-dispersion mortar has reached the required curing age, remove and recycle the casing (3).

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