Anchoring device for torsion test of fiber reinforced polymer rib anchor rod

Abstract

The utility model relates to the technical field of anchoring, in particular to an anchoring device for a torsion test of a fiber reinforced polymer bar anchor rod, which comprises anchoring sleeves sleeved at two ends of the fiber reinforced polymer bar anchor rod, and an anti-skid layer is arranged on the outer surface of each anchoring sleeve and comprises metal wires arranged at set intervals along the axial direction of the anchoring sleeve. According to the invention, during a torsion test, two ends of the fiber reinforced polymer rib anchor rod clamped by a torsion testing machine cannot be damaged due to clamping of a clamp of the torsion testing machine, the phenomenon that the clamping ends slip during the torsion test is solved, and the problem that the fiber reinforced polymer rib anchor rod cannot be directly subjected to the torsion test is solved; therefore, the torsion performance of the fiber reinforced polymer rib anchor rod can be directly known through the torsion testing machine, and a theoretical basis is provided for popularization and application of the fiber reinforced polymer rib anchor rod.

Description

Technical Field

[0001] The utility model relates to the technical field of anchoring, in particular to an anchoring device used for a torsion test of a fiber reinforced polymer tendon anchor rod. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Fiber reinforced polymer (FRP) materials can gradually replace traditional steel materials as anchor rods due to their advantages such as corrosion resistance, high strength and light weight. Therefore, FPR (fiber reinforced polymer) tendon anchor rods can be widely used in highway, bridge and concrete reinforcement projects, fundamentally solving the problem of reinforcement structure failure caused by steel corrosion.

[0004] Anchor rods of different structures, materials and types need to undergo relevant tests to determine their actual application performance. Taking the torsion test as an example, the torsion test of metal materials will make the metal specimens with diameters at both ends larger than the diameter of the middle gauge section to facilitate clamping at both ends; if the FRP tendon anchor rod is directly installed on the torsion testing machine for clamping, the weak shear resistance of the FRP tendon anchor rod will cause its anchoring end to be crushed, making it impossible to perform the test operation; on the other hand, when the torsional load increases, the clamp will often slip with the steel casing at the clamping end, making it impossible to test the actual torque; at the same time, due to the relatively weak shear resistance of the FRP tendon anchor rod, it cannot be made into a shape with diameters at both ends larger than the diameter of the middle gauge section like steel bars.

[0005] The prior art provides some devices for connecting FRP tendon anchor rods, most of which are designed based on the coordination between the FRP tendon anchor rods and the rock and soil layers. Although the FRP tendon anchor rods can be anchored, their operation mode and structure are not suitable for torsion testing by a torsion testing machine, and the slipping problem that occurs during the torsion test is not solved. Utility Model Content

[0006] In order to solve the above problems, the utility model proposes an anchoring device for torsion test of fiber reinforced polymer tendon anchor rods, which can prevent the two ends of the FRP tendon anchor rods clamped by the torsion test machine from being damaged due to being clamped by the clamp of the torsion test machine during the torsion test of the FRP tendon anchor rods, and also solve the problem of slipping of the clamping ends during the torsion test, breaking through the difficult problem that the FRP tendon anchor rods cannot be directly subjected to torsion test, so that the torsion performance of the FRP tendon anchor rods can be directly understood through the torsion test machine, and providing a theoretical basis for the promotion and application of the FRP tendon anchor rods.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod comprises anchoring sleeves sleeved on both ends of the fiber reinforced polymer tendon anchor rod, an anti-skid layer is arranged on the outer surface of the anchoring sleeve, and the anti-skid layer comprises metal wires arranged at set intervals along the axial direction of the anchoring sleeve.

[0009] Furthermore, the space between the fiber reinforced polymer anchor rod and the anchor sleeve is filled with anchor glue.

[0010] Furthermore, a first fixing rubber strip and a second fixing rubber strip are provided at both ends of the anchoring sleeve.

[0011] Furthermore, the first fixing rubber strip and the second fixing rubber strip are respectively filled into the space between the fiber reinforced polymer tendon anchor rod and the anchor sleeve.

[0012] Furthermore, the first fixing rubber strip and the second fixing rubber strip are bonded to the inner side of the anchoring sleeve.

[0013] Furthermore, the fiber reinforced polymer tendon anchor rod is coaxially sleeved with the anchor sleeve.

[0014] Further, the outer surface of the anchor sleeve is used to connect with the clamping end of the torsion test equipment.

[0015] Furthermore, the torsion test device has a movable end, and fixed ends are arranged on both sides of the movable end.

[0016] Furthermore, a clamping end is provided on a side of the movable end close to one of the fixed ends, and the clamping end is used to connect with the outer surface of the anchoring sleeve.

[0017] Furthermore, a guide member is provided between the mobile end and the other fixed end, for guiding the direction of the mobile end when it moves between the two fixed ends.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] 1. By sleeve-fitting anchor sleeves at both ends of the fiber reinforced polymer (FRP) anchor rod, the problem that the FRP anchor rod cannot be directly subjected to pull-out test due to its poor shear resistance is solved. The metal wire on the surface of the anchor sleeve forms an anti-slip layer, which solves the problem of slipping easily when using a torsion testing machine for testing, making the test data more reliable.

[0020] 2. The anchor sleeve is bonded to both ends of the FRP tendon anchor rod by anchor glue, and cooperates with two sets of fixing strips to improve the shear resistance of the clamped area of ​​the FRP tendon anchor rod. It can also maintain the FRP tendon anchor rod in the axial position of the anchor sleeve, solving the problem that the FRP tendon anchor rod cannot be directly subjected to pull-out test due to poor shear resistance.

[0021] 3. The device assembly process is simple, the raw materials are extensive and the cost is low. The device can be assembled by one person. Compared with other devices, it is more suitable for test operations, making it easier to understand the torsional performance of FRP tendon anchors, and providing a data basis for the promotion and application of FRP tendon anchors.

[0022] 4. The device has a simple structure and is widely applicable. It can be used for the anchoring and protection of most FRP tendon anchors, and is convenient for conducting FRP tendon anchor torsion tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute a limitation on the present invention.

[0024] Figure 1 It is a structural schematic diagram of the anchoring device provided by the utility model;

[0025] Figure 2 It is a side structural schematic diagram of the anchoring device provided by the utility model;

[0026] Figure 3 It is a schematic diagram of the cross-sectional structure of the anchoring sleeve on one side provided by the utility model;

[0027] Figure 4 It is a structural schematic diagram of the anchoring device provided by the utility model being clamped on a torsion testing machine.

[0028] In the figure: 1 FRP reinforcement anchor rod, 2 anchor sleeve, 3-1 first fixing rubber strip, 3-2 second fixing rubber strip, 4 anti-slip steel wire, 5-1 first fixed end, 5-2 second fixed end, 6 movable end, 7 guide piece, 8 clamping end. DETAILED DESCRIPTION

[0029] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0030] It should be noted that the following detailed descriptions are exemplary and are intended to provide further description of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] As introduced in the background technology, the torsion test of metal materials will make the metal specimen into a shape with the diameter of both ends larger than the diameter of the middle gauge section to facilitate clamping at both ends, but the shear resistance of FRP tendon anchor rods is relatively weak, and they cannot be made into a shape that is conducive to clamping like steel bars; if the FRP tendon anchor rods are directly installed on the torsion testing machine for clamping, the weak shear resistance of the FRP tendon anchor rods will cause their anchoring ends to be crushed, making it impossible to perform the test operation, so a clamp (such as a steel pipe sleeve) is used to solve the crushing problem; and when the torsional load increases, the clamp often slips with the steel sleeve at the clamping end, making it difficult to test the actual torque.

[0032] The prior art CN117489045A provides a device for connecting FRP tendon anchor rods, which can also anchor the FRP tendon anchor rods, but its operation method is not suitable for individual operation and does not solve the problem of slippage during torsion testing.

[0033] The prior art CN117127757A provides a FRP tendon anchor clip-type anchoring device, which is also not suitable for manual operation, and the required anchor size is too large, and is not suitable for torsion testing on a torsion testing machine.

[0034] The prior art CN106906956A proposes an anchoring device, which can be manually operated for anchoring, but the operation is complicated and the cost is high.

[0035] In summary, most of the devices for connecting FRP tendon anchors provided in the prior art are designed based on the coordination between the FRP tendon anchor and the rock and soil layer. Although the FRP tendon anchor can be anchored, its structure and operation method are not suitable for torsion testing by a torsion testing machine, and the slipping problem that occurs during the torsion test is not solved.

[0036] Therefore, the following embodiment provides an anchoring device for torsion test of fiber reinforced polymer tendon anchor rods, which can prevent the two ends of the FRP tendon anchor rods clamped by the torsion testing machine from being damaged due to being clamped by the clamps of the torsion testing machine during the torsion test of the FRP tendon anchor rods. At the same time, it also solves the problem of slipping at the clamping ends during the torsion test, breaking through the difficult problem that the FRP tendon anchor rods cannot be directly subjected to torsion tests, making it possible to directly understand the torsion performance of the FRP tendon anchor rods through the torsion testing machine, and providing a theoretical basis for the promotion and application of FRP tendon anchor rods.

[0037] like Figure 1-Figure 4As shown, an anchoring device for a torsion test of a fiber reinforced polymer tendon anchor comprises an anchoring sleeve 2 sleeved on both ends of a FRP tendon anchor 1, a tendon embedding glue is filled between the FRP tendon anchor 1 and the anchoring sleeve 2, a first fixing rubber strip 3-1 and a second fixing rubber strip 3-2 are provided at both ends of the anchoring sleeve 2, an anti-slip layer is provided on the outer surface of the anchoring sleeve 2, and the outer surface of the anchoring sleeve 2 is used to connect with the clamping end 8 of the torsion test equipment.

[0038] The length of the FRP tendon anchor rod 1 can be set between 300 and 500 mm, depending on the gauge length of the FRP tendon anchor rod 1 required for the test, and the diameter can be set between 18 and 32 mm, depending on the test requirements and the measuring range of the test instrument used.

[0039] The anchor sleeve 2 may be a steel pipe with a length of 100 to 200 mm and a thickness of 3 to 7 mm, which is specifically determined according to the size of the FRP tendon anchor 1 and the test plan.

[0040] Before assembling the device, the surface of the anchor sleeve 2 must be roughened to form an anti-skid layer to prevent slipping during the test. The roughening method is to weld a 100mm long and 2-4mm diameter anti-skid steel wire 4 on the outer surface of the anchor sleeve 2 at intervals of 10-15mm in the axial direction. The material of the anti-skid steel wire 4 can be Q195, Q215, or Q235 stainless steel wire.

[0041] The anchor glue is filled between the FRP tendon anchor rod 1 and the anchor sleeve 2. The fixing strips 3-1 and 3-2 are located at both ends of the anchor sleeve 2 and are filled into the space between the FRP tendon anchor rod 1 and the anchor sleeve 2 to prevent the anchor glue from overflowing and ensure that the FRP tendon anchor rod 1 can be in the axial position of the anchor sleeve 2.

[0042] In this embodiment, the sizes of the anchor sleeve 2 and the fixing rubber strips 3-1 and 3-2 corresponding to the FRP tendon anchor rod 1 are shown in Table 1.

[0043] Table 1: Dimensions of anchor sleeves and fixing strips corresponding to FRP reinforcement anchor rods Note: The length of the FRP reinforcement anchor rods in the table is 300 mm

[0044]

[0045] The fixing rubber strips 3-1 and 3-2 are made of rubber and can be directly customized or cut by yourself. The thickness can be between 2-4 mm, the inner diameter can be between 18-32 mm, and the outer diameter can be between 28-47 mm. Double-sided adhesive can be used to stick them to the inner sides of both ends of the anchor sleeve 2.

[0046] The torsion test equipment can be a torsion test machine or a universal test machine, and the specific model is selected according to the material to be tested. The test is completed by connecting the clamping end thereof with the outer surface of the anchor sleeve 2.

[0047] By sticking anchor sleeves on both ends of the FRP tendon anchor rod, the problem that the FRP tendon anchor rod cannot be directly subjected to pull-out test due to its poor shear resistance is solved. This overcomes the difficulty of not being able to directly conduct pull-out test on the FRP tendon anchor rod, making it easier to understand the torsional performance of the FRP tendon anchor rod, and provides a data basis for the promotion and application of the FRP tendon anchor rod.

[0048] The device is easy to assemble, the raw materials are extensive and the cost is low, and the device can be assembled by one person. Compared with other devices, it is more suitable for test operations.

[0049] The device solves the problem that the test piece is prone to slipping when using a torsion testing machine for testing, making the test data more reliable.

[0050] The device has a simple structure and is widely applicable. It can be used for the anchoring and protection of most FRP tendon anchors and is convenient for conducting torsion tests of FRP tendon anchors.

[0051] Taking the operation of performing a torsion test using the anchoring device of this embodiment as an example, the specific working process of the anchoring device is described, which includes the following steps:

[0052] An anti-slip steel wire 4 is vertically welded on the surface of the anchor sleeve 2 along the outer wall.

[0053] The cut first fixing rubber strip 3 - 1 is pasted to the inner edge of the outer end of the anchoring sleeve 2 by double-sided tape.

[0054] Place the anchor sleeve 2 with one end of the first fixing strip 3-1 installed facing downward on a flat surface, such as a flat wooden board or stone slab, and pour the well-proportioned rebar embedding glue into the interior of the anchor sleeve 2 from the other end of the anchor sleeve 2. Stop pouring when it reaches 1 / 3 of the interior of the anchor sleeve 2.

[0055] The cut second fixing rubber strip 3 - 2 is pasted on the other end of the anchoring sleeve 2 at a position where the first fixing rubber strip 3 - 1 is not installed by using double-sided tape.

[0056] Place the FRP tendon anchor rod into the anchor sleeve 2 along the second fixing rubber strip 3-2 until it passes through the first fixing rubber strip 3-1, ensuring that the outer end of the FRP tendon anchor rod 1, the outer end of the anchor sleeve 2, and the first fixing rubber strip 3-1 are in the same plane.

[0057] Let the installed device stand for a while to allow the anchor glue to fully solidify.

[0058] Install the statically cured device on the torsion testing machine, first move the movable end 6 to the position of the first fixed end 5-1, then clamp the second fixed end 5-2, and then move the movable end 6 toward the second fixed end 5-2, adjust the device to a suitable clamping position, and start the test after ensuring that the clamping end 8 is clamped.

[0059] The torque-angle curve and data are output by the torsion testing machine and further processed.

[0060] Another set of test processes includes the following steps:

[0061] On the surface of the anchor sleeve 2, a non-slip steel wire made of Q215 stainless steel, 100 mm long and 4 mm in diameter is welded vertically at intervals of 15 mm along the outer wall.

[0062] The fixed rubber strips 3-1 and 3-2 used are self-cut rubber strips with a thickness of 2mm, an inner diameter of 25mm and an outer diameter of 40mm. Double-sided tape is used to stick them inside the two ends of the steel casing 2. The cut fixed rubber strip 3-1 is pasted on the inner edge of the outer end of the anchor casing 2 with double-sided tape.

[0063] Place the anchor sleeve 2 with the end of the fixing strip 3-1 downward on a flat wooden board or stone slab, and pour the well-proportioned anchor glue into the anchor sleeve 2 from the other end of the anchor sleeve 2. Stop when it is poured into 1 / 3 of the anchor sleeve 2.

[0064] The cut fixing rubber strip 3 - 2 is pasted to the position of the other end of the anchoring sleeve 2 where the fixing rubber strip 3 - 1 is not installed by using double-sided tape.

[0065] The FRP tendon anchor rod 1 used is 300mm long, 25mm in diameter, and made of GFRP (glass fiber reinforced polymer). The FRP tendon anchor rod 1 is placed into the anchor sleeve 2 along the fixing rubber strip 3-2. The anchor sleeve 2 used in the present invention is made of 20# carbon steel (seamless steel pipe), with a length of 100mm, a diameter of 50mm, and a thickness of 5mm. It is enough to pass through the fixing rubber strip 3-1, ensuring that the outer end of the FRP tendon anchor rod 1, the outer end of the anchor sleeve 2, and the fixing rubber strip 3-1 are in the same plane.

[0066] Let the installed device stand for a while to allow the anchor glue to fully solidify.

[0067] This test uses a torsion testing machine of model NDW31000, which has a movable end 6 and a first fixed end 5-1 and a second fixed end 5-2 located on both sides of the movable end, a clamping end 8 is provided on the side close to the movable end 6 and one of the fixed ends (5-2), and a guide member 7 is provided between the movable end 6 and the other fixed end (5-1);

[0068] In this embodiment, the movable end 6 is first moved to the position of the fixed end 5-1, and the direction is guided by the guide member 7 (such as a slide rail) during the movement. Then, one end of the material is clamped on the clamping end 8. Next, the movable end 6 is moved closer to the fixed end 5-2 until it reaches a suitable clamping position and then the other end of the material is clamped. After ensuring that the clamping end 8 is clamped, the test can be started.

[0069] According to the torque-angle curve output by the torsion testing machine, the torsion modulus of the FRP anchor can be obtained by taking the smoother section according to the following formula:

[0070]

[0071] Where G is the torsional modulus of the FRP anchor rod 1, MPa; ΔT is the difference in torque of the selected smooth section, N·m; L e is the parallel length of the specimen, i.e. the length between the two anchor sections, m; I p =πd 4 / 32, d is the diameter of the FRP anchor rod 1.

[0072] Although the above describes the specific implementation methods of the utility model in combination with the accompanying drawings, it is not intended to limit the scope of protection of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. An anchoring device for torsion test of fiber reinforced polymer tendon anchor, characterized in that: The invention comprises an anchoring sleeve sleeved on both ends of a fiber reinforced polymer tendon anchor rod, an anti-skid layer is arranged on the outer surface of the anchoring sleeve, and the anti-skid layer comprises metal wires arranged at set intervals along the axial direction of the anchoring sleeve.

2. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 1, characterized in that: The space between the fiber reinforced polymer anchor rod and the anchor sleeve is filled with anchor glue.

3. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 1, characterized in that: The two ends of the anchoring sleeve are provided with a first fixing rubber strip and a second fixing rubber strip.

4. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 3, characterized in that: The first fixing rubber strip and the second fixing rubber strip are respectively filled into the space between the fiber reinforced polymer tendon anchor rod and the anchor sleeve.

5. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 3, characterized in that: The first fixing rubber strip and the second fixing rubber strip are bonded to the inner side of the anchoring sleeve.

6. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 1, characterized in that: The fiber reinforced polymer tendon anchor rod is coaxially sleeved with the anchor sleeve.

7. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 1, characterized in that: The outer surface of the anchor sleeve is used to connect with the clamping end of the torsion test equipment.

8. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 7, characterized in that: The torsion test device has a moving end, and fixed ends are arranged on both sides of the moving end.

9. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 8, characterized in that: A clamping end is provided on one side of the movable end close to one of the fixed ends, and the clamping end is used to be connected to the outer surface of the anchoring sleeve.

10. An anchoring device for torsion test of fiber reinforced polymer tendon anchor rod according to claim 8, characterized in that: A guide is provided between the movable end and the other fixed end, for guiding the direction of the movable end when it moves between the two fixed ends.

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