CFRP prestressed tendon composite anchorage device and anchoring method thereof

Abstract

The invention belongs to the technical field of anchorage devices, and particularly discloses a CFRP prestressed tendon composite anchorage device and an anchoring method thereof, and the composite anchorage device comprises a pipe body, a binder layer, an anchor cup, a clamping piece and a locking piece. The CFRP prestressed tendons are sleeved with the pipe body, the pipe body and the CFRP prestressed tendons form filling gaps, and the filling gaps are filled with the adhesive layers. And the anchor cup is sleeved outside the pipe body on one side far away from the end plug block. And the clamping piece is clamped between the pipe body and the anchor cup. The locking piece is fixed to the pipe body and attached to the end, away from the anchor cup, of the clamping piece. The end plugging block is of a cylindrical structure with one closed end and one open end, a through hole is formed in the closed end of the cylindrical structure of the end plugging block along the central axis of the cylindrical structure, and the through hole is in transition fit with the CFRP prestressed tendon. According to the anchoring method, the composite anchorage device is used for anchoring the CFRP prestressed tendons. According to the invention, the problems of anchoring efficiency, safety and durability of the CFRP rib are systematically solved.

Description

Technical Field

[0001] This invention belongs to the field of anchorage technology, and specifically relates to a CFRP prestressed tendon composite anchorage and its anchoring method. Background Technology

[0002] Bridge cable-stayed systems are the main load-bearing components of long-span bridges such as cable-stayed bridges and suspension bridges, while anchorages are a crucial force transmission device within the cable-stayed system. CFRP (Carbon Fiber Reinforced Polymer) reinforcements, with their advantages of high strength, corrosion resistance, and lightweight construction, play an irreplaceable role in structures with special requirements such as harsh environments, long spans, and lightweight designs, and are widely used in bridge cable-stayed systems. CFRP is a composite material made by bonding multiple strands of continuous carbon fiber as reinforcing fibers and thermosetting resin as the matrix material, then rapidly curing it through extrusion and drawing using a mold with a fixed cross-sectional shape. CFRP prestressed tendons, on the other hand, apply prestress to CFRP reinforcements.

[0003] Improving anchorage efficiency has always been a key technical challenge in the design of CFRP prestressed tendon anchors. Currently, CFRP prestressed tendon anchors can be categorized into wedge-type anchors, bonded anchors, and composite anchors based on their anchorage mechanisms. Existing CFRP tendon anchors primarily rely on friction or the shear strength of fasteners to anchor the CFRP tendons. However, CFRP tendons have low transverse shear strength, and the anchorage end face is prone to a notching effect when under tension, leading to damage and fatigue failure of the CFRP tendon, ultimately causing the entire anchorage system to fail. When the CFRP tendon is under tension, the wedges need to move in a timely manner to ensure the tendon is gradually clamped. However, in practical applications, timely wedge movement cannot be guaranteed, often requiring a large preload. Excessive preload can also negatively impact the stress on the CFRP tendon and the anchorage effect.

[0004] During the adhesive filling process of the composite anchor bonding section, the use of traditional end-plug gaskets often causes the carbon fiber reinforcement to tilt inside the tube, resulting in uneven bonding. After the adhesive cures, the tilted carbon fiber reinforcement will slip and fail under tension due to uneven stress, preventing the CFRP reinforcement from performing its excellent performance.

[0005] Therefore, there is a need to provide a composite anchorage for CFRP prestressed tendons and its anchoring method to optimize and solve the above problems. Summary of the Invention

[0006] To address the aforementioned problems, the purpose of this invention is to provide a CFRP prestressed tendon composite anchor and its anchoring method.

[0007] The technical solution of this invention is: a composite anchorage for CFRP prestressed tendons, comprising a tube body, an adhesive layer, an anchor cup, a clamping plate, and a locking element. The tube body is sleeved on the outside of the CFRP prestressed tendon, and a filling gap is formed between the inner wall of the tube body and the outer wall of the CFRP prestressed tendon.

[0008] It also includes an end plug, which is a cylindrical structure with one end closed and the other end open. The end plug has a through hole along the axis for passing through the CFRP prestressing tendon. The through hole and the CFRP prestressing tendon are transitionally fitted. One end of the tube is inserted into the end plug along the open end of the end plug.

[0009] The adhesive layer fills the filling gap; the anchor cup is sleeved on the tube body on the side away from the end block; the clamp is locked between the tube body and the anchor cup; the locking member is fixed on the tube body, and the locking member is attached to the end of the clamp away from the anchor cup.

[0010] Furthermore, the inner wall of the end plug is provided with a first thread, and the outer wall of one end of the tube is provided with a second thread corresponding to the first thread. The tube thread is provided at the open end of the cylindrical structure of the end plug.

[0011] Furthermore, the ratio of the effective length of the first thread to the inner wall length of the end plug is 0.7~0.9:1, and the end of the pipe thread set inside the end plug forms a reserved gap between the end of the end plug and the closed end of the cylindrical structure of the end plug, and the adhesive layer is also filled in the reserved gap.

[0012] Furthermore, a third thread is provided on the outer wall of the end of the tube away from the end plug, and the locking element is a locking nut, which has a first internal thread that matches the third thread.

[0013] Furthermore, the clip has a segmented structure, comprising 3 to 5 sub-clamps, which together form a hollow conical structure.

[0014] Furthermore, the side of the sub-clamp closest to the tube body and the middle section of the outer wall of the tube body are both provided with a rough structure.

[0015] Furthermore, the pipe body includes a first pipe body and a second pipe body. One end of the first pipe body is fixed to the open end of the end-plug cylindrical structure. One end of the second pipe body is connected to the other end of the first pipe body and is an integral structure with the first pipe body. The diameter of the second pipe body decreases sequentially from the end away from the first pipe body to the other end, and the minimum diameter of the second pipe body is equal to the diameter of the first pipe body.

[0016] Furthermore, the tube hole of the second tube is a frustum structure with an inclination angle of 0.5° to 1°.

[0017] Furthermore, a washer is provided at the contact point between the locking member and the clamping piece, and the washer is sleeved on the tube body.

[0018] An anchoring method for CFRP prestressed tendons, utilizing the aforementioned composite anchor, specifically includes: inserting one end of the tube into the end block along the open end of the end block; passing the CFRP prestressed tendon through the through hole and the tube, filling the gap with an adhesive layer; fitting the anchor cup onto the tube, and securing the clamp between the tube and the anchor cup; fixing the locking member to the tube and ensuring that the locking member and the end of the clamp are in contact; pre-tensioning the CFRP prestressed tendon to press the locking member against the end of the clamp, thus completing the anchoring of the CFRP prestressed tendon.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention systematically solves the problems of efficiency, safety and durability of CFRP bar anchorage through three core innovations: composite anchoring mechanism, stress dispersion design and dynamic clamping control.

[0020] This method combines wedge-type and adhesive-type anchors in parallel to form a synergistic composite anchoring mechanism. Based on the dual anchoring of the adhesive layer and the wedges, load sharing is achieved. The adhesive layer disperses the initial stress, and the wedges dynamically supplement the anchoring force through the wedge tightening effect, greatly improving the anchoring efficiency coefficient, far exceeding that of a single anchoring method.

[0021] Among them, the transition fit of the end plug and the flexible constraint of the tube effectively suppress the cutting effect, reduce stress concentration on the anchor end face, and reduce the risk of CFRP reinforcement damage. The rigid connection between the locking component and the tube forces the clamp to follow up in time, avoiding slippage failure, while reducing the dependence on preload and protecting the stress performance of the CFRP reinforcement.

[0022] The added locking device effectively ensures that the tube body and the CFRP prestressing tendon are coaxial, resulting in a regular filling gap structure. The filling gap is a columnar structure with an annular cross-section. Therefore, when the adhesive layer is applied, the locking device locks the tube body, effectively preventing the CFRP prestressing tendon from tilting inside the tube body and causing uneven bonding. Attached Figure Description

[0023] Figure 1 This is a front sectional view of the present invention; Figure 2 This is a left sectional view of the present invention; Figure 3 This is a schematic diagram of the end block of the present invention; Figure 4 This is a schematic diagram of the tube body of the present invention.

[0024] Among them, 1-end plug, 11-through hole, 12-first thread, 2-pipe body, 201-first pipe body, 202-second pipe body, 21-second thread, 22-third thread, 23-second internal thread, 3-adhesive layer, 4-anchor cup, 5-clamping piece, 6-locking piece, 60-washer ring. Detailed Implementation

[0025] The following is combined with Figures 1 to 4 The specific embodiments of the present invention will be described in detail below. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0027] Example like Figure 1 , Figure 2 The diagram illustrates a composite anchorage for CFRP prestressed tendons, comprising an end block 1, a tube body 2, an adhesive layer 3, an anchor cup 4, a clamping piece 5, and a locking element 6. The end block 1 is a cylindrical structure with one closed end and one open end. The end block 1 has a through hole 11 along its axis, through which the CFRP prestressed tendon passes, and the through hole 11 is fitted with the CFRP prestressed tendon. The tube body 2 is fitted over the CFRP prestressed tendon, and a filling gap is formed between the inner wall of the tube body 2 and the outer wall of the CFRP prestressed tendon. One end of the tube body 2 is inserted into the end block 1 along its open end. The adhesive layer 3 fills the filling gap. The anchor cup 4 is fitted over the tube body 2 on the side away from the end block 1. The clamping piece 5 is secured between the tube body 2 and the anchor cup 4. The locking element 6 is fixed to the tube body 2, and the locking element 6 is fitted with the end of the clamping piece 5 away from the anchor cup 4.

[0028] Preferred, such as Figure 3 As shown, the inner wall of the end plug 1 is provided with a first thread 12, and the outer wall of one end of the tube body 2 is provided with a second thread 21 corresponding to the first thread 12. The tube body 2 is threaded at the open end of the cylindrical structure of the end plug 1.

[0029] Preferably, the ratio of the effective length of the first thread 12 to the inner wall length of the end plug 1 is 0.7~0.9:1. A reserved gap is formed between the end of the pipe body 2 with its thread inside the end plug 1 and the closed end of the cylindrical structure of the end plug 1. The adhesive layer 3 is also filled within this reserved gap. By filling the reserved gap with the adhesive layer 3, the inner surface of the sealing end of the end plug 1 contacts the adhesive layer 3. The adhesive layer 3 in the reserved gap and the adhesive layer 3 in the filling gap form an integral structure. The adhesive layer 3 in the reserved gap can limit the adhesive layer 3 in the filling gap, effectively preventing interface slippage between the adhesive layer 3 in the filling gap and the pipe body 2.

[0030] Preferred, such as Figure 4 As shown, a third thread 22 is provided on the outer wall of the end of the pipe body 2 away from the end plug 1, and the locking member 6 is a locking nut, which has a first internal thread that matches the third thread 22.

[0031] Preferably, the clip 5 has a segmented structure, and the clip 5 includes 3 to 5 sub-clamps 50, which form a hollow conical structure.

[0032] Preferably, the side of the sub-clamp 50 near the tube body 2 and the middle section of the outer wall of the tube body 2 are provided with a rough structure.

[0033] Preferred, such as Figure 4 As shown, the tube body 2 includes a first tube body 201 and a second tube body 202. One end of the first tube body 201 is fixed to the open end of the cylindrical structure of the end plug 1. One end of the second tube body 202 is connected to the other end of the first tube body 201, and the two are integrally formed. The diameter of the second tube body 202 decreases sequentially from the end furthest from the first tube body 201 to the other end, and the minimum diameter of the second tube body 202 is equal to the diameter of the first tube body 201. The tube hole of the second tube body 202 adopts a gradually changing diameter, which can effectively prevent interface slippage between the adhesive-free layer 3 and the tube body 2.

[0034] It should be noted that: such as Figure 4 As shown, the second thread 21 is disposed on the outer surface of the end of the second tube 202 away from the first tube 201, and the third thread 22 is disposed on the outer surface of the end of the first tube 201 away from the second tube 202. In this embodiment, the length of the first tube 201 is equal to the length of the second tube 202.

[0035] Preferably, the tube hole of the second tube 202 is a frustum structure with an inclination angle of 0.5° to 1°. In this embodiment, the inclination angle of the frustum structure is preferably 0.5°.

[0036] The design of the straight cylinder and inner cone inside the tube 2 can prevent interface slippage between the adhesive layer 3 and the tube 2, improve the static load performance and fatigue resistance of the composite anchor, and thus ensure the efficient anchoring of the CFRP prestressed tendons in the bonded section and its anchoring effect.

[0037] Preferably, a second internal thread 23 is provided on the inner side of the end of the second tube 202 away from the first tube 201. The second internal thread 23 does not serve as a mechanical thread for assembly, but rather increases the contact area between the second tube 202 and the adhesive layer 3, thereby effectively preventing slippage.

[0038] Preferably, a washer 60 is provided at the contact point between the locking member 6 and the clamping piece 5, and the washer 60 is sleeved on the tube body 2.

[0039] Preferably, the adhesive layer 3 is formed by filling and solidifying with an adhesive. In this embodiment, the adhesive is a high-performance epoxy resin.

[0040] Preferably, the end plug 1, pipe body 2, anchor cup 4, clamping plate 5, and locking component 6 are all made of corrosion-resistant aluminum alloy metal.

[0041] It should be noted that the length of tube 2 is longer than the effective length of anchor cup 4 and clamping plate 5.

[0042] An anchoring method for CFRP prestressed tendons, utilizing the composite anchor proposed in this embodiment, specifically includes: inserting one end of the tube body 2 into the end block 1 along the open end of the end block 1; passing the CFRP prestressed tendon through the through hole 11 and the tube body 2, filling the gap with adhesive to form an adhesive layer 3; fitting the anchor cup 4 onto the tube body 2, and securing the clamping piece 5 between the tube body 2 and the anchor cup 4; fixing the locking member 6 onto the tube body 2, ensuring that the locking member 6 and the end of the clamping piece 5 are in contact; pre-tensioning the CFRP prestressed tendon, causing the locking member 6 to press against the end of the clamping piece 5, thus completing the anchoring of the CFRP prestressed tendon.

[0043] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A composite anchor for CFRP prestressed tendons, comprising a tube body (2), an adhesive layer (3), an anchor cup (4), a clamping piece (5), and a locking element (6); the tube body (2) is sleeved on the outside of the CFRP prestressed tendon, and a filling gap is formed between the inner wall of the tube body (2) and the outer wall of the CFRP prestressed tendon; the adhesive layer (3) fills the filling gap; Its features are, It also includes an end plug (1), which is a cylindrical structure with one end closed and the other end open. The end plug (1) has a through hole (11) along the axis. The through hole (11) is used to pass through the CFRP prestressing tendon. The through hole (11) and the CFRP prestressing tendon are transitionally fitted. One end of the tube body (2) is inserted into the end plug (1) along the open end of the end plug (1). The anchor cup (4) is fitted onto the outside of the tube body (2) on the side away from the end plug (1); The clamp (5) is engaged between the tube body (2) and the anchor cup (4); The locking element (6) is fixed on the tube body (2), and the locking element (6) is attached to the end of the clamp (5) away from the anchor cup (4).

2. The CFRP prestressed tendon composite anchorage as described in claim 1, characterized in that, The inner wall of the end plug (1) is provided with a first thread (12), and the outer wall of one end of the tube (2) is provided with a second thread (21) corresponding to the first thread (12). The thread of the tube (2) is provided at the opening end of the cylindrical structure of the end plug (1).

3. The CFRP prestressed tendon composite anchorage as described in claim 2, characterized in that, The effective length of the first thread (12) is 0.7~0.9:1 to the inner wall length of the end plug (1). The end of the pipe body (2) with the thread set inside the end plug (1) forms a reserved gap between the end of the cylindrical structure of the end plug (1) and the closed end. The adhesive layer (3) is also filled in the reserved gap.

4. The CFRP prestressed tendon composite anchorage as described in claim 1, characterized in that, The outer side wall of the tube body (2) away from the end block (1) is provided with a third thread (22), and the locking element (6) is a locking nut, which has a first internal thread that matches the third thread (22).

5. A CFRP prestressed tendon composite anchor as described in claim 1, characterized in that, The clip (5) is a segmented structure, and the clip (5) includes 3 to 5 sub-clamps (50), which together form a hollow cone structure.

6. A CFRP prestressed tendon composite anchorage as described in claim 5, characterized in that, The sub-clamp (50) has a rough structure on the side of the tube (2) near the tube body (2) and in the middle section of the outer wall of the tube body (2).

7. A CFRP prestressed tendon composite anchorage as described in claim 1, characterized in that, The tube (2) includes: The first tube (201) is fixed at one end to the opening end of the cylindrical structure of the end plug (1); The second tube (202) is connected at one end to the other end of the first tube (201) and is an integral structure with the first tube (201). The diameter of the second tube (202) decreases sequentially from the end away from the first tube (201) to the other end. The minimum diameter of the second tube (202) is equal to the diameter of the first tube (201).

8. A CFRP prestressed tendon composite anchorage as described in claim 7, characterized in that, The second tube (202) has a truncated cone structure with an inclination angle of 0.5° to 1°.

9. A CFRP prestressed tendon composite anchorage as described in claim 1, characterized in that, A washer (60) is also provided at the contact point between the locking member (6) and the clamp (5), and the washer (60) is sleeved on the tube body (2).

10. A method for anchoring CFRP prestressed tendons, characterized in that, Anchoring CFRP prestressing tendons using the composite anchorage described in any one of claims 1-9 specifically includes: Insert one end of the tube body (2) into the end plug (1) along the open end of the end plug (1); The CFRP prestressed tendons are passed through the through hole (11) and the pipe body (2), and the adhesive layer (3) is filled in the filling gap. The anchor cup (4) is fitted onto the tube body (2), and the clamp (5) is clamped between the tube body (2) and the anchor cup (4); Fix the locking part (6) on the pipe body (2) and ensure that the locking part (6) and the end of the clamp (5) are in contact; pre-tension the CFRP prestressed tendon so that the locking part (6) presses the end of the clamp (5) to complete the anchoring of the CFRP prestressed tendon.

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