An FRP / steel composite confining uhpc anchor plate system and method of use thereof

Abstract

The application provides an FRP / steel composite constraint UHPC anchor plate system and a use method thereof, and solves the problem that the anchor hole of the existing anchor plate is difficult to repair after deformation, and the anchor plate is made of a whole thick steel plate, so that the weight of the anchor plate is large, the cost is high, and the transportation and assembly are laborious. The application reduces the steel material proportion of the original anchor plate structure, replaces the steel material with a large amount of FRP material and UHPC material, saves the cost, and reduces the overall weight of the anchor plate structure. Meanwhile, the composite anchor plate is assembled by using a plurality of detachable accessories, the weight of each accessory is reduced, and the transportation and assembly are facilitated. The outer layer constraint is made of steel material with better vertical shear resistance, the problem of low shear strength caused by the weak strength of the FRP material in the vertical fiber direction is avoided, the structure is more scientific and reasonable, and the deformation resistance is better.

Description

Technical Field

[0001] This invention relates to the field of prestressed tensioning technology, and in particular to an FRP / steel composite constrained UHPC anchor plate system and its application method. Background Technology

[0002] Prestressing involves applying tension to a structural member in advance, causing it to bear compressive stress and thus deform to cope with the loads on the structure, including the member's own weight, wind loads, snow loads, and seismic loads. This improves the member's bending resistance and stiffness, delays the appearance of cracks, and increases the member's durability.

[0003] Prestressed tensioning generally requires steel strands, jacks, anchor plates, anchors, etc. Among them, the material used for anchor plates is mostly made of a single piece of thick steel plate. When using such anchor plates, there are the following problems: (1) When the anchor hole of the anchor plate is in tensioning, due to the large force exerted by the anchor on the wall of the anchor hole, the inner wall of the anchor hole is difficult to repair after deformation, resulting in a low service life of the anchor plate; (2) The anchor plate is made of a single piece of thick steel plate, which results in its large weight, high cost, and relatively difficult transportation and assembly. Summary of the Invention

[0004] To address the problems in the prior art where existing anchor plates are difficult to repair after the anchor holes are deformed, and where the anchor plates are made of a single piece of thick steel plate, resulting in high weight, high cost, and labor-intensive transportation and assembly, this invention proposes an FRP / steel composite restraint UHPC anchor plate system and its application method.

[0005] The technical solution of the present invention is: an FRP / steel composite confined UHPC anchor plate system, comprising multiple sets of composite anchor plates and steel pads, wherein the steel pads are steel plate structures with multiple wire holes for steel strands to pass through;

[0006] The composite anchor plate includes an outer constraint steel sleeve made of steel. The outer constraint steel sleeve includes a steel sleeve tube and a base plate. The steel sleeve tube is a tubular structure that is open from left to right. The base plate is fixed at the right end of the steel sleeve tube to close the right end of the steel sleeve tube. The base plate is provided with multiple first through holes that are open from left to right. The first through holes are connected to the interior of the steel sleeve tube and are used for steel strands to pass through.

[0007] The interior of the steel sleeve is filled with a first UHPC anchor plate and an inner steel anchor plate from right to left. The first UHPC anchor plate is prefabricated as a whole UHPC. The outer circumferential surfaces of the first UHPC anchor plate and the inner steel anchor plate are in contact with the inner surface of the steel sleeve. The steel sleeve is used to constrain the first UHPC anchor plate and the inner steel anchor plate.

[0008] The first UHPC anchor plate has multiple first conical holes that are open to the left and right and are larger on the left and smaller on the right. The first conical holes correspond to the first through holes one by one. The first conical holes are equipped with detachable first FRP conical sleeves.

[0009] The inner steel anchor plate is provided with multiple second conical holes that are open on both sides and larger on the left and smaller on the right. The second conical holes correspond one-to-one with the second through holes.

[0010] The inner diameter of the second tapered hole and the inner hole of the first FRP tapered sleeve are a continuous tapered hole structure with the inner diameter gradually decreasing from left to right.

[0011] The steel strand passes through the first through hole, the first FRP tapered sleeve, and the second tapered hole from right to left;

[0012] An anchor with a tapered sleeve structure is inserted into the second tapered hole. The anchor is sleeved on the steel strand, and the left end of the anchor extends to the outside of the second tapered hole. The maximum diameter of the anchor is greater than the maximum inner diameter of the second tapered hole. The right end of the anchor is inserted into the first FRP tapered sleeve.

[0013] Preferably, the first through hole is a tapered hole structure that is open from left to right and larger on the left and smaller on the right, and the second tapered hole, the inner hole of the first FRP tapered sleeve and the first through hole are continuous tapered hole structures with gradually decreasing inner diameter from left to right.

[0014] The minimum inner diameter of the first through hole is smaller than the minimum outer diameter of the anchor, and the right end of the anchor is inserted into the first through hole.

[0015] Preferably, the interior of the steel sleeve is filled with a first UHPC anchor plate, an inner steel anchor plate and a second UHPC anchor plate from right to left, and the second UHPC anchor plate is prefabricated as a whole UHPC.

[0016] The outer peripheral surfaces of the first UHPC anchor plate, the inner steel anchor plate, and the second UHPC anchor plate are in contact with the inner surface of the steel sleeve. The steel sleeve is used to constrain the first UHPC anchor plate, the inner steel anchor plate, and the second UHPC anchor plate.

[0017] The second UHPC anchor plate has multiple third conical holes that are open to the left and right and are larger on the left and smaller on the right. The third conical holes are equipped with detachable second FRP conical sleeves.

[0018] The inner hole of the second FRP tapered sleeve, the second tapered hole and the inner hole of the first FRP tapered sleeve are a continuous tapered hole structure with the inner diameter gradually decreasing from left to right.

[0019] The maximum inner diameter of the second FRP tapered sleeve is smaller than the maximum outer diameter of the anchor. The anchor is inserted into the second FRP tapered sleeve, the second tapered hole, and the first FRP tapered sleeve.

[0020] Preferably, a left-right open inner restraint FRP sleeve is movably inserted into the inner side of the steel sleeve, and the outer peripheral surface of the inner restraint FRP sleeve contacts the inner surface of the steel sleeve.

[0021] The inner constraint FRP sleeve is fitted on the outside of the first UHPC anchor plate, the inner steel anchor plate, and the second UHPC anchor plate. The inner constraint FRP sleeve is used to constrain the first UHPC anchor plate, the inner steel anchor plate, and the second UHPC anchor plate.

[0022] Preferably, an FRP anchor plate is fixedly connected to the left end of the inner constraint FRP sleeve, and the FRP anchor plate is used to close the left port of the inner constraint FRP sleeve.

[0023] The FRP anchor plate has multiple through holes on both sides, which correspond to the inner holes of the second FRP cone sleeve. The through holes are used for steel strands and anchors to pass through.

[0024] Preferably, the second through hole is a tapered hole structure with a larger diameter on the left and a smaller diameter on the right. The second through hole, the inner hole of the second FRP tapered sleeve, the second tapered hole and the inner hole of the first FRP tapered sleeve are a continuous tapered hole structure with the inner diameter gradually decreasing from left to right.

[0025] The maximum inner diameter of the second through hole is smaller than the maximum outer diameter of the anchor. The anchor is inserted into the second through hole, the second FRP tapered sleeve, the second tapered hole, and the first FRP tapered sleeve.

[0026] Preferably, the steel sleeve, the first UHPC anchor plate, the inner steel anchor plate, the second UHPC anchor plate, and the inner restraint FRP sleeve are all cone structures with a larger left side and a smaller right side.

[0027] A method for using an FRP / steel composite restraint UHPC anchor plate system includes the following steps: S1~ Using UHPC material, n+1 sets of first UHPC anchor plates and second UHPC anchor plates are prefabricated using molds; using steel, n+1 sets of outer restraint steel sleeves and inner lining steel anchor plates are prefabricated; the steel sleeve of the outer restraint steel sleeve and the base plate are welded together; using FRP material, n+1 sets of first FRP cone sleeves, second FRP cone sleeves, FRP anchor plates and inner restraint FRP sleeves are prefabricated using molds; wherein, the FRP anchor plates and the inner restraint FRP sleeves are prefabricated as a single unit to form accessories for n+1 sets of composite anchor plates; wherein n sets of composite anchor plates are used to be installed in the ports of the steel strand holes of the bridge precast slab as fixed end composite anchor plates; and the remaining set of composite anchor plates is used as a detachable movable end composite anchor plate.

[0028] S2 ~ Tensioning construction preparation stage, the outer restraint steel sleeve, the first UHPC anchor plate, the first FRP cone sleeve, the inner lining steel anchor plate, the second UHPC anchor plate, the second FRP cone sleeve, the FRP anchor plate, the inner restraint FRP sleeve, and the anchor are sequentially sleeved on the steel strand to form a fixed end composite anchor plate. The fixed end composite anchor plate is then pushed into the port of the steel strand hole in the bridge precast slab, and the fixed end composite anchor plate abuts against the tensioning anchor plate embedded in the bridge precast slab.

[0029] S3~ A steel pad is fitted onto the steel strand so that the steel pad abuts against the anchor of the fixed end composite anchor plate;

[0030] S4~ Place the through-hole hydraulic jack on the steel strand and make one end of the through-hole hydraulic jack abut against the steel pad.

[0031] S5~Refer to step S2, assemble the movable end composite anchor plate on the steel strand, so that the movable end composite anchor plate abuts against the other end of the through-hole hydraulic jack.

[0032] S6~ Inspect the movable end composite anchor plate, the through-hole hydraulic jack, the steel pad plate, and the fixed end composite anchor plate. After the inspection is qualified, control the through-hole hydraulic jack to extend. One end of the through-hole hydraulic jack abuts against the steel pad plate, and the other end of the through-hole hydraulic jack abuts against the bottom plate of the outer constraint steel sleeve of the movable end composite anchor plate. Start tensioning. After tensioning is completed, remove the movable end composite anchor plate, the through-hole hydraulic jack, and the steel pad plate in sequence.

[0033] S7~ Inject UHPC grout into the steel strand hole to fill the gap in the steel strand hole and fix the fixed end composite anchor plate in the steel strand hole by the UHPC grout.

[0034] Advantages of the present invention: (1) The present invention reduces the steel content of the original anchor plate structure. The composite anchor plate uses a large amount of FRP and UHPC materials to replace steel, saving costs and reducing the overall weight of the anchor plate structure. At the same time, the composite anchor plate is assembled with multiple detachable parts, reducing the weight of each part when it is picked up and put down, and making it easier to transport and assemble. Moreover, if the anchor hole of a certain part of the composite anchor plate at the movable end deforms, the anchor plate structure can be reused as a whole by replacing the part, which can improve the service life and save costs.

[0035] (2) The outer constraint of the present invention is made of steel with better resistance to vertical shear, which avoids the problem of low shear strength caused by the weak strength of FRP material perpendicular to the fiber direction. The structure is more scientific and reasonable and has better resistance to deformation.

[0036] (3) After tensioning, the fixed end composite anchor plate left in the port of the steel strand hole of the bridge precast slab contains a multi-layer FRP-UHPC-steel composite material, which enables the steel strand in the bridge precast slab to obtain better isolation from the corrosive environment in highly corrosive environments such as marine engineering, thus extending the service life of the steel strand. At the same time, the fixed end composite anchor plate can also strengthen the structural strength at the port of the steel strand hole, thus obtaining better crack resistance at that location. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the external structure from the main view angle after the anchor plate is installed on the steel strand in Example 1.

[0039] Figure 2 for Figure 1 A schematic diagram of the internal structure at the junction of the anchor plate and the steel strand 1 from a main view angle;

[0040] Figure 3 for Figure 1 A schematic diagram of the external structure of the anchor plate from the left view angle;

[0041] Figure 4 for Figure 1 A schematic diagram of the external structure of the anchor plate from the right-hand view angle;

[0042] Figure 5 for Figure 1 A schematic diagram of the internal structure of the outer constraint steel sleeve from the main view angle;

[0043] Figure 6 for Figure 1 A schematic diagram of the internal structure of the first UHPC anchor plate from the main view angle;

[0044] Figure 7 for Figure 6 A schematic diagram of the internal structure of the first FRP cone sleeve from the main view angle;

[0045] Figure 8 for Figure 1 A schematic diagram of the internal structure of the inner steel anchor plate from the main view angle;

[0046] Figure 9 for Figure 1 A schematic diagram of the internal structure of the second UHPC anchor plate from the main view angle;

[0047] Figure 10 for Figure 9 A schematic diagram of the internal structure of the second FRP cone sleeve from the main view angle;

[0048] Figure 11 for Figure 1 A schematic diagram of the internal structure of the internally constrained FRP sleeve from the main view angle;

[0049] In the figure, 1. Steel strand, 2. Outer restraint steel sleeve, 201. First slot, 3. First UHPC anchor plate, 4. Inner steel anchor plate, 401. Second conical hole, 5. Second UHPC anchor plate, 6. First FRP conical sleeve, 7. Second FRP conical sleeve, 8. FRP anchor plate, 801. Second through hole, 9. Inner restraint FRP sleeve, 10. Anchor, 11. Steel pad. Detailed Implementation

[0050] 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.

[0051] Example 1: An FRP / steel composite confined UHPC anchor plate system, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, it includes n+1 sets of composite anchor plates and steel pads 11.

[0052] Where n is the same as the sum of the number of steel strand holes in all the bridge precast slabs required for construction, n sets of composite anchor plates are used to be installed in the port of the steel strand hole of the bridge precast slab as fixed end composite anchor plates, and the remaining set of composite anchor plates is used as detachable movable end composite anchor plates.

[0053] The steel pad 11 is a steel plate structure with multiple wire holes for the steel strands 1 to pass through.

[0054] The composite anchor plate includes an outer constraint steel sleeve 2 made of steel, such as Figure 5 As shown, the outer constraint steel sleeve 2 includes a steel sleeve and a base plate. The steel sleeve is a tubular structure that is open on both sides. The base plate is fixed at the right end of the steel sleeve to close the right port of the steel sleeve. The base plate is provided with a plurality of first through holes that are open on both sides. The first through holes are connected to the interior of the steel sleeve and are used for the steel strand 1 to pass through.

[0055] The inner side of the steel sleeve is movably inserted with an inner restraint FRP sleeve 9 that is open on both sides, and the outer circumferential surface of the inner restraint FRP sleeve 9 is in contact with the inner surface of the steel sleeve.

[0056] The interior of the inner constraint FRP sleeve 9 is filled from right to left with a first UHPC anchor plate 3, an inner steel anchor plate 4, and a second UHPC anchor plate 5.

[0057] Both the first UHPC anchor plate 3 and the second UHPC anchor plate 5 are prefabricated as a single UHPC unit.

[0058] The outer peripheral surfaces of the first UHPC anchor plate 3, the inner steel anchor plate 4, and the second UHPC anchor plate 5 are in contact with the inner surface of the inner restraint FRP sleeve 9, which is used to restrain the first UHPC anchor plate 3, the inner steel anchor plate 4, and the second UHPC anchor plate 5.

[0059] In order to enhance the structural strength of the inner constraint FRP sleeve 9 and to make the first UHPC anchor plate 3, the inner steel anchor plate 4, and the second UHPC anchor plate 5 have stronger resistance to deformation as a whole with the inner constraint FRP sleeve 9 during tensioning, an FRP anchor plate 8 is fixedly connected to the left end of the inner constraint FRP sleeve 9. The FRP anchor plate 8 is used to close the left port of the inner constraint FRP sleeve 9.

[0060] The FRP anchor plate 8 is provided with multiple second through holes 804 that are open to the left and right. The second through holes 804 correspond to the inner holes of the second FRP cone sleeve 7. The second through holes 804 are used to allow the steel strand 1 and the anchor 10 to pass through.

[0061] like Figure 6 As shown, the first UHPC anchor plate 3 has multiple first conical holes that are open on both sides and larger on the left and smaller on the right. The first conical holes correspond one-to-one with the first through holes. A detachable device, such as..., is inserted into the first conical hole. Figure 7 The first FRP tapered sleeve 6 is shown.

[0062] like Figure 8 As shown, the inner steel anchor plate 4 is provided with multiple second conical holes 401 that are open to the left and right and are larger on the left and smaller on the right. The second conical holes 401 correspond to the second through holes one by one.

[0063] The inner diameter of the second tapered hole 401 and the inner hole of the first FRP tapered sleeve 6 are a continuous tapered hole structure with the inner diameter gradually decreasing from left to right.

[0064] like Figure 9 As shown, the second UHPC anchor plate 5 has multiple third conical holes that are open on both sides and larger on the left and smaller on the right. Removable components, such as..., are inserted into these third conical holes. Figure 10 The second FRP tapered sleeve 7 is shown.

[0065] The second through hole 804 is a tapered hole structure with a larger diameter on the left and a smaller diameter on the right. The inner hole of the second through hole 804, the inner hole of the second FRP tapered sleeve 7, the second tapered hole 401, and the inner hole of the first FRP tapered sleeve 6 are continuous tapered hole structures with gradually decreasing inner diameters from left to right. The maximum inner diameter of the second through hole 804 is smaller than the maximum outer diameter of the anchor 10.

[0066] An anchor 10 with a tapered sleeve structure is inserted into the second tapered hole 401. The anchor 10 is sleeved on the steel strand 1, and the left end of the anchor 10 extends to the outside of the second tapered hole 401. The maximum diameter of the anchor 10 is greater than the maximum inner diameter of the second tapered hole 401. The anchor 10 is inserted into the second through hole 804, the second FRP tapered sleeve 7, the second tapered hole 401, and the first FRP tapered sleeve 6.

[0067] In order to ensure that the base plate of the outer restraint steel plate 2 can also directly play a role in resisting deformation during tensioning, such as Figure 5 As shown, the first through hole is a tapered hole structure that is open from left to right and larger on the left and smaller on the right. The second tapered hole 401, the inner hole of the first FRP tapered sleeve 6, and the first through hole are continuous tapered hole structures with gradually decreasing inner diameters from left to right. The minimum inner diameter of the first through hole is smaller than the minimum outer diameter of the anchor 10, and the right end of the anchor 10 is inserted into the first through hole.

[0068] The steel sleeve, the first UHPC anchor plate 3, the inner steel anchor plate 4, the second UHPC anchor plate 5, and the inner restraint FRP sleeve 6 are all cone structures with a larger left side and a smaller right side.

[0069] A method for using an FRP / steel composite restraint UHPC anchor plate system includes the following steps: S1~ Using UHPC material, n+1 sets of first UHPC anchor plates 3 and second UHPC anchor plates 5 are prefabricated using molds; n+1 sets of outer restraint steel sleeves 2 and inner lining steel anchor plates 4 are prefabricated using steel; the steel sleeve and base plate of the outer restraint steel sleeve 2 are welded together; using FRP material, n+1 sets of first FRP cone sleeves 6, second FRP cone sleeves 7, FRP anchor plates 8 and inner restraint FRP sleeves 9 are prefabricated using molds; wherein, the FRP anchor plates 8 and inner restraint FRP sleeves 9 are prefabricated as a single unit to form accessories for n+1 sets of composite anchor plates; wherein n sets of composite anchor plates are used to be installed in the ports of the steel strand holes of the bridge precast slab as fixed end composite anchor plates; and the remaining set of composite anchor plates is used as a detachable movable end composite anchor plate.

[0070] Where n is the same as the sum of the number of steel strand holes in all the precast bridge slabs required for construction.

[0071] S2 ~ Tensioning construction preparation stage, the outer restraint steel sleeve 2, the first UHPC anchor plate 3, the first FRP cone sleeve 6, the inner lining steel anchor plate 4, the second UHPC anchor plate 5, the second FRP cone sleeve 7, the FRP anchor plate 8, the inner restraint FRP sleeve 9, and the anchor 10 are sequentially sleeved on the steel strand 1 to form a fixed end composite anchor plate. The fixed end composite anchor plate is then pushed into the port of the steel strand hole in the bridge precast slab, and the fixed end composite anchor plate abuts against the tensioning anchor plate pre-embedded in the bridge precast slab.

[0072] S3~ A steel pad 11 is fitted onto the steel strand 1, so that the steel pad 11 abuts against the anchor 10 of the fixed end composite anchor plate.

[0073] S4~ Place the through-hole hydraulic jack on the steel strand 1, and make one end of the through-hole hydraulic jack abut against the steel pad 11.

[0074] S5~Referring to step S2, assemble the movable end composite anchor plate on the steel strand 1, so that the movable end composite anchor plate abuts against the other end of the through-hole hydraulic jack.

[0075] S6~ Inspect the movable end composite anchor plate, the through-hole hydraulic jack, the steel pad 11, and the fixed end composite anchor plate. After the inspection is qualified, control the through-hole hydraulic jack to extend. One end of the through-hole hydraulic jack abuts against the steel pad 11, and the other end of the through-hole hydraulic jack abuts against the bottom plate of the outer constraint steel sleeve 2 of the movable end composite anchor plate. Start tensioning. After tensioning is completed, remove the movable end composite anchor plate, the through-hole hydraulic jack, and the steel pad 11 in sequence.

[0076] S7~ Inject UHPC grout into the steel strand hole to fill the gap in the steel strand hole and fix the fixed end composite anchor plate in the steel strand hole by the UHPC grout.

[0077] Working principle: When tensioning the steel strand 1, the first FRP cone sleeve 6, the second FRP cone sleeve 7, the inner steel anchor plate 4, the FRP anchor plate 8, and the bottom plate of the outer constraint steel sleeve 2 provide the first layer of constraint for the anchor 10. The first layer of constraint is mainly formed by the composite constraint of FRP material and steel material.

[0078] The first UHPC anchor plate 3 and the second UHPC anchor plate 5 respectively constrain the first FRP cone sleeve 6 and the second FRP cone sleeve 7, forming a second layer of constraint on the anchor 10 through indirect action. The first UHPC anchor plate 3 and the second UHPC anchor plate 5 are mainly used to resist the deformation of the first FRP cone sleeve 6 and the second FRP cone sleeve 7. The second layer of constraint is mainly provided by UHPC (ultra-high performance concrete) material.

[0079] The inner constraint FRP sleeve 9 constrains the first UHPC anchor plate 3, the inner steel anchor plate 4, and the second UHPC anchor plate 5, forming a third layer of constraint that provides secondary indirect action on the anchor 10. The third layer of constraint is mainly provided by FRP material.

[0080] The steel sleeve of the outer constraint steel sleeve 2 directly constrains the FRP anchor plate 8, the inner constraint FRP sleeve 9, and the base plate of the outer constraint steel sleeve 2. This forms a multi-type composite constraint system, including FRP material-steel (FRP anchor plate 8 - steel sleeve of outer constraint steel sleeve 2), steel-steel (base plate of outer constraint steel sleeve 2 - steel sleeve of outer constraint steel sleeve 2), and FRP material-UHPC material-FRP material-steel (FRP cone sleeve - UHPC anchor plate - inner constraint FRP sleeve - steel sleeve), resulting in superior deformation resistance of the device during use.

[0081] During tensioning, since the anchor 10 has a conical structure, when the anchor 10 exerts a film-expanding effect on the anchor plate structure, the direction of its force is not always a vertical force in the up-down direction, but also has a compressive force in the left-right direction. Therefore, the present invention adds an inner steel anchor plate 4 between the first UHPC anchor plate 3 and the second UHPC anchor plate 5 to improve the internal resistance to horizontal deformation of the anchor plate structure.

[0082] Since FRP (fiber-reinforced polymer) is formed by the polymerization of fibers through a matrix, the strength between fibers is determined by the matrix (which is generally weaker than the fiber strength), resulting in weaker strength perpendicular to the fiber direction. FRP also has low shear strength, only 5% to 20% of its tensile strength. Therefore, FRP is unsuitable as the outer constraint material for anchor plate structures. Thus, the outer constraint steel sleeve 2 of this invention is made of steel, not FRP.

[0083] Meanwhile, after deformation occurs at the inner holes of the first FRP cone sleeve 6, the second FRP cone sleeve 7, the FRP anchor plate 8, and the outer constraint steel sleeve 2, the anchor plate structure as a whole can be reused by replacing a certain component, thus saving costs.

[0084] After tensioning, the fixed-end composite anchor plate left in the port of the steel strand hole in the bridge precast slab contains multiple layers of FRP-UHPC-steel composite material. This allows the fixed-end composite anchor plate to better isolate the steel strand in the bridge precast slab from corrosion in highly corrosive environments such as marine engineering, thus extending the service life of the steel strand. At the same time, the fixed-end composite anchor plate can also strengthen the structural strength at the port of the steel strand hole, resulting in better crack resistance at that location.

[0085] This invention reduces the steel content of the original anchor plate structure. The composite anchor plate extensively uses FRP and UHPC materials to replace steel, saving costs and reducing the overall weight of the anchor plate structure. Simultaneously, the composite anchor plate is assembled using multiple detachable components, reducing the weight of individual components during handling and facilitating transportation and assembly. Furthermore, if the anchor hole of a component on the movable end of the composite anchor plate deforms, the entire anchor plate structure can be reused by replacing that component, extending its service life and saving costs.

[0086] Example 2: An FRP / steel composite restrained UHPC anchor plate system. This example differs from Example 1 in that the first through hole is a through hole of equal diameter, and the minimum inner diameter of the first FRP tapered sleeve 6 is greater than the minimum outer diameter of the anchor 10. Other structural features are the same as in Example 1.

[0087] Example 3: An FRP / steel composite constrained UHPC anchor plate system. This example differs from Example 2 in that the FRP anchor plate 8 is no longer provided, the maximum inner diameter of the second FRP cone sleeve 7 is smaller than the maximum outer diameter of the anchor 10, and the anchor 10 is inserted into the second FRP cone sleeve 7, the second conical hole 401, and the first FRP cone sleeve 6. Other structures are the same as in Example 2.

[0088] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims and not by the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An FRP / steel composite confined UHPC anchor plate system, characterized in that: It includes multiple sets of composite anchor plates and steel pads (11), the steel pads (11) being a steel plate structure with multiple wire holes for steel strands (1) to pass through; The composite anchor plate includes an outer constraint steel sleeve (2) made of steel. The outer constraint steel sleeve (2) includes a steel sleeve and a base plate. The steel sleeve is a tubular structure that is open from left to right. The base plate is fixed at the right end of the steel sleeve to close the right end of the steel sleeve. The base plate is provided with multiple first through holes that are open from left to right. The first through holes are connected to the inside of the steel sleeve. The first through holes are used for the steel strand (1) to pass through. The interior of the steel sleeve is filled with a first UHPC anchor plate (3), an inner steel anchor plate (4), and a second UHPC anchor plate (5) from right to left. The second UHPC anchor plate (5) is prefabricated as a UHPC unit. The outer periphery of the first UHPC anchor plate (3), the inner steel anchor plate (4), and the second UHPC anchor plate (5) are in contact with the inner side of the steel sleeve. The steel sleeve is used to constrain the first UHPC anchor plate (3), the inner steel anchor plate (4), and the second UHPC anchor plate (5). The first UHPC anchor plate (3) has multiple first conical holes that are open to the left and right and are larger on the left and smaller on the right. The first conical holes correspond to the first through holes one by one. The first conical holes are equipped with detachable first FRP conical sleeves (6). The inner steel anchor plate (4) is provided with multiple second conical holes (401) that are open to the left and right and are larger on the left and smaller on the right. The second conical holes (401) correspond to the second through holes one by one. The inner holes of the second tapered hole (401) and the first FRP tapered sleeve (6) are continuous tapered hole structures with gradually decreasing inner diameters from left to right. The steel strand (1) passes through the first through hole, the first FRP tapered sleeve (6), and the second tapered hole (401) from right to left. An anchor (10) with a conical sleeve structure is inserted into the second conical hole (401). The anchor (10) is sleeved on the steel strand (1). The left end of the anchor (10) extends to the outside of the second conical hole (401). The maximum diameter of the anchor (10) is greater than the maximum inner diameter of the second conical hole (401). The right end of the anchor (10) is inserted into the first FRP cone sleeve (6); The second UHPC anchor plate (5) has multiple third conical holes that are open to the left and right and are larger on the left and smaller on the right. The third conical holes are equipped with a detachable second FRP conical sleeve (7). The inner hole of the second FRP tapered sleeve (7), the second tapered hole (401) and the inner hole of the first FRP tapered sleeve (6) are a continuous tapered hole structure with the inner diameter gradually decreasing from left to right. The maximum inner diameter of the second FRP cone sleeve (7) is smaller than the maximum outer diameter of the anchor (10). The anchor (10) is inserted into the second FRP cone sleeve (7), the second cone hole (401) and the first FRP cone sleeve (6). The inner side of the steel sleeve is movably inserted with a left and right open inner restraint FRP sleeve (9), and the outer peripheral surface of the inner restraint FRP sleeve (9) is in contact with the inner surface of the steel sleeve. The inner constraint FRP sleeve (9) is fitted on the outside of the first UHPC anchor plate (3), the inner steel anchor plate (4) and the second UHPC anchor plate (5). The inner constraint FRP sleeve (9) is used to constrain the first UHPC anchor plate (3), the inner steel anchor plate (4) and the second UHPC anchor plate (5). An FRP anchor plate (8) is fixedly connected to the left end of the inner constraint FRP sleeve (9). The FRP anchor plate (8) is used to close the left port of the inner constraint FRP sleeve (9). The FRP anchor plate (8) is provided with multiple second through holes (804) that are open to the left and right. The second through holes (804) correspond to the inner holes of the second FRP cone sleeve (7) on the left and right. The second through holes (804) are used to allow the steel strand (1) and the anchor (10) to pass through.

2. The FRP / steel composite confined UHPC anchor plate system as described in claim 1, characterized in that: The first through hole is a tapered hole structure that is open to both sides and larger on the left and smaller on the right. The second tapered hole (401), the inner hole of the first FRP tapered sleeve (6) and the first through hole are continuous tapered hole structures with gradually decreasing inner diameter from left to right. The minimum inner diameter of the first through hole is smaller than the minimum outer diameter of the anchor (10), and the right end of the anchor (10) is inserted into the first through hole.

3. The FRP / steel composite confined UHPC anchor plate system as described in claim 1, characterized in that: The second through hole (804) is a tapered hole structure with a larger diameter on the left and a smaller diameter on the right. The inner hole of the second through hole (804), the inner hole of the second FRP tapered sleeve (7), the second tapered hole (401) and the inner hole of the first FRP tapered sleeve (6) are a continuous tapered hole structure with a gradually decreasing inner diameter from left to right. The maximum inner diameter of the second through hole (804) is smaller than the maximum outer diameter of the anchor (10). The anchor (10) is inserted into the second through hole (804), the second FRP tapered sleeve (7), the second tapered hole (401) and the first FRP tapered sleeve (6).

4. The FRP / steel composite confined UHPC anchor plate system as described in claim 1, characterized in that: The steel sleeve, the first UHPC anchor plate (3), the inner steel anchor plate (4), the second UHPC anchor plate (5) and the inner restraint FRP sleeve (9) are all cone structures with a larger left side and a smaller right side.

5. The method of using the FRP / steel composite confined UHPC anchor plate system as described in claim 1 or 3, characterized in that, Includes the following steps: S1~Using UHPC material, n+1 sets of first UHPC anchor plates (3) and second UHPC anchor plates (5) are prefabricated using molds. Using steel, n+1 sets of outer constraint steel sleeves (2) and inner lining steel anchor plates (4) are prefabricated. The steel sleeve and bottom plate of the outer constraint steel sleeve (2) are welded together. Using FRP material, n+1 sets of first FRP cone sleeves (6), second FRP cone sleeves (7), FRP anchor plates (8) and inner constraint FRP sleeves (9) are prefabricated using molds. Among them, the FRP anchor plates (8) and inner constraint FRP sleeves (9) are prefabricated as a whole to form accessories for n+1 sets of composite anchor plates. Among them, n sets of composite anchor plates are used to be installed in the port of the steel strand hole of the bridge prefabricated plate as fixed end composite anchor plates. The remaining set of composite anchor plates is used as detachable movable end composite anchor plates. S2~Tensioning construction preparation stage, the outer restraint steel sleeve (2), the first UHPC anchor plate (3), the first FRP cone sleeve (6), the inner lining steel anchor plate (4), the second UHPC anchor plate (5), the second FRP cone sleeve (7), the FRP anchor plate (8), the inner restraint FRP sleeve (9), and the anchor (10) are sequentially sleeved on the steel strand (1) to form a fixed end composite anchor plate. The fixed end composite anchor plate is pushed into the port of the steel strand hole of the bridge precast slab, and the fixed end composite anchor plate abuts against the tensioning anchor plate embedded in the bridge precast slab. S3~ A steel pad (11) is fitted on the steel strand (1) so that the steel pad (11) abuts against the anchor (10) of the fixed end composite anchor plate; S4~ Place the through-hole hydraulic jack on the steel strand (1) and make one end of the through-hole hydraulic jack abut against the steel pad (11); S5~Referring to step S2, assemble the movable end composite anchor plate on the steel strand (1) so that the movable end composite anchor plate abuts against the other end of the through-hole hydraulic jack. S6~ Inspect the movable end composite anchor plate, the through-hole hydraulic jack, the steel pad (11), and the fixed end composite anchor plate. After the inspection is qualified, control the through-hole hydraulic jack to extend. One end of the through-hole hydraulic jack abuts against the steel pad (11), and the other end of the through-hole hydraulic jack abuts against the bottom plate of the outer constraint steel sleeve (2) of the movable end composite anchor plate. Start tensioning. After tensioning is completed, remove the movable end composite anchor plate, the through-hole hydraulic jack, and the steel pad (11) in sequence. S7~ Inject UHPC grout into the steel strand hole to fill the gap in the steel strand hole and fix the fixed end composite anchor plate in the steel strand hole by the UHPC grout.

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