Fatigue-resistant FRP anchoring device

Abstract

A fiber reinforced plastic (FRP) anchoring device suitable for fatigue resistance relates to a prestressed anchoring device and comprises an anchorage device and an anchor backing plate, a vector backing plate is mounted between the anchorage device and the anchor backing plate, the vector backing plate is an annular double-spherical-surface steel backing plate, and the vector backing plate and the anchor backing plate are directly connected through a spherical pair. The vector base plate and the anchorage device are directly or indirectly connected through a spherical pair. A pressure sensor is further installed between the vector base plate and the anchorage device, one end of the pressure sensor is a plane end, and the other end of the pressure sensor is a spherical end. The end face, making contact with the pressure sensor, of the anchorage device is a straight end face, the straight end face directly presses the plane end of the pressure sensor, and the spherical end of the pressure sensor is connected with the vector base plate through a spherical pair. Normal exertion of the performance of the FRP inhaul cable can be guaranteed, the actual adaptability of FRP can be improved, and the FRP inhaul cable has the advantages that installation is easy, it can be guaranteed that the stress states of the FRP ribs are consistent, the stress uniformity of the FRP rib bundle is effectively improved, stress data collection is more comprehensive, real and effective and the like, and application and popularization are easy.

Description

Technical Field

[0001] The invention relates to a prestressed anchoring device, in particular to a fatigue-resistant FRP anchoring device. Background Art

[0002] Fiber reinforced composites (FRP) have excellent properties of light weight, high strength, corrosion resistance and fatigue resistance. They are new materials that achieve long life, corrosion resistance and low maintenance costs for engineering structures. They have been widely studied and applied in post-tensioned concrete projects. The FRP composite bars commonly used in engineering structures are mainly reinforced composite materials with new high-performance inorganic materials such as GFRP, CFRP, and BFRP as reinforcements. Since the tensile strength of FRP is much higher than that of traditional steel, when it is used as the main material of prestressed tendons, the traditional prestressed tendon anchoring structure is not suitable for FRP tendons with higher specific strength and specific stiffness, which restricts the excellent tensile and fatigue resistance of FRP tendons.

[0003] In order to ensure good fatigue performance, FRP tendon anchors usually use cold-cast bonded anchors and parallel tendon bundles to increase the stress coefficient of FRP tendons, so as to improve material utilization and reduce costs. However, the anchor structure used is a traditional anchor structure based on steel prestressed tendons such as steel strands. The single spherical anchor structure used in the traditional anchor structure has a forced centering effect, which brings higher end additional lateral loads and additional bending moments. It is only suitable for fatigue performance requirements of millions of times, while FRP, which is more sensitive to lateral loads, has fatigue performance of up to tens of millions of times. If the traditional anchor structure is used, it will greatly restrict the performance of FRP cables, and also lead to poor actual adaptability and high cost of use of FRP. In addition, due to the high stress level of FRP, it is difficult for traditional cable force real-time monitoring methods to obtain comprehensive and accurate data during service. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a fatigue-resistant FRP anchoring device to solve the shortcomings of the prior art, such as restricting the performance of FRP cables, poor practical adaptability of FRP and high use cost.

[0005] The technical solution to solve the above technical problems is: a fatigue-resistant FRP anchoring device, including an anchor and an anchor plate. The anchor is anchored on the FRP cable body, and a vector plate is installed between the anchor and the anchor plate. The vector plate is a circular double-spherical steel plate. The vector plate and the anchor plate are directly connected through a spherical pair, and the vector plate and the anchor are directly or indirectly connected through a spherical pair.

[0006] A further technical solution of the present invention is that the anchor and the vector pad are directly connected via a spherical pair.

[0007] A further technical solution of the present invention is: the anchor comprises an anchor sleeve and a working nut, the anchor sleeve is anchored on the FRP cable body, the working nut is connected to the anchor sleeve through a thread, one end of the working nut is a spherical end, and the spherical end is directly connected to the vector pad through a spherical pair.

[0008] A further technical solution of the present invention is: the anchor comprises an integral composite anchor, one end of the integral composite anchor is a spherical end, and the spherical end is directly connected to the vector pad through a spherical pair.

[0009] A further technical solution of the present invention is: a pressure sensor is also installed between the vector pad and the anchor, one end of the pressure sensor is a plane end, and the other end is a spherical end; the end face of the anchor in contact with the pressure sensor is a straight end face, which is directly pressed on the plane end of the pressure sensor, and the spherical end of the pressure sensor is connected to the vector pad through a spherical pair.

[0010] A further technical solution of the present invention is: the anchor comprises an anchor sleeve and a working nut, the anchor sleeve is anchored on the FRP cable body, the working nut is connected to the anchor sleeve by a thread, both ends of the working nut are straight end faces, and the straight end face of the working nut is directly pressed on the plane end of the pressure sensor.

[0011] A further technical solution of the present invention is: the anchor comprises an integral composite anchor, both ends of the integral composite anchor are straight end faces, and the integral composite anchor is directly pressed flat on the plane end of the pressure sensor.

[0012] A further technical solution of the present invention is: the upper end surface of the vector pad is an upper inner spherical surface, the lower end surface of the vector pad is a lower outer spherical surface, the radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface.

[0013] A further technical solution of the present invention is that the centers of the spherical surfaces of the spherical surface pairs are all in the same direction.

[0014] A further technical solution of the present invention is: the pressure sensor is a graphene composite material elastomer.

[0015] Due to the above structure, the fatigue-resistant FRP anchoring device of the present invention has the following beneficial effects compared with the prior art: 1. Ensure the normal performance of FRP cables The present invention installs a vector pad between the anchor and the anchor pad, wherein the vector pad is a circular double-spherical steel pad, the vector pad is directly connected to the anchor pad through a spherical pair, and the vector pad is directly or indirectly connected to the anchor through a spherical pair. The present invention arranges a vector pad with double spherical surfaces between the anchor and the anchor pad, so that the anchor and the vector pad, and the vector pad and the anchor pad can be connected through a spherical pair, thereby avoiding the disadvantages caused by the single spherical anchor structure in the traditional anchor structure, and can be applied to the fatigue performance of FRP up to tens of millions of times, ensuring the normal performance of the FRP cable.

[0016] 2. Can improve the actual adaptability of FRP The present invention arranges a vector pad with double spherical surfaces between the anchor and the anchor pad, so that the anchor and the vector pad, as well as the vector pad and the anchor pad can be connected through spherical pairs, so that the FRP cable body has a larger adjustment angle, thereby improving the actual adaptability of FRP.

[0017] Furthermore, in order to adjust the centripetal force of the anchor and reduce the influence of the centripetal additional transverse anchorage load between the anchor and the FRP composite tendons of the FRP cable body, the radius of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface. After the double spherical surface adjustment, the adaptive deflection angle of the FRP cable body reaches more than 8°, which is more than twice that of the traditional anchoring structure.

[0018] 3. Easy to install Since the present invention can adapt to a larger installation angle and self-adapt to the center, it is easy to install.

[0019] 4. Can ensure the consistency of stress state of each FRP bar The present invention arranges a vector pad with double spherical surfaces between the anchor and the anchor pad, so that the anchor and the vector pad, as well as the vector pad and the anchor pad can be connected through a spherical pair, and the cable body axis vector can be adjusted, effectively ensuring that the stress state of each FRP tendon is consistent.

[0020] Furthermore, the centers of the spherical surfaces of the spherical surface pair of the present invention are all in the same direction, so that the axes between the FRP cable body and the anchor can achieve the consistent effect of being adjusted in the same direction.

[0021] 5. Effectively improve the uniformity of FRP tendon stress The present invention can dynamically release the secondary transverse additional stress through the vector shear of the structural spherical pair, effectively improving the force uniformity of the FRP tendon bundle and the fatigue performance of the anchor assembly.

[0022] 6. Stress data collection is more comprehensive, true and effective, and low cost The present invention also installs a pressure sensor between the vector pad and the anchor, which can perform in-situ component monitoring of the intelligent structural component. It has a simple structure, and the stress data collection is more comprehensive, true and effective, and the cost is lower.

[0023] Furthermore, the pressure sensor of the present invention is a graphene composite elastomer, which utilizes the sensing characteristics of the graphene composite to combine the sensor and the anchoring structure into one, which can not only give full play to the force performance of the structure, but also play a role in force monitoring during service, and can give full play to the effect of in-situ original component monitoring.

[0024] The technical features of a fatigue-resistant FRP anchoring device of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : A schematic structural diagram of a fatigue-resistant FRP anchoring device according to the present invention described in Example 1; Figure 2 : A schematic structural diagram of a fatigue-resistant FRP anchoring device according to the present invention described in Example 2; Figure 3 : A schematic structural diagram of a fatigue-resistant FRP anchoring device according to the present invention described in Example 3; Figure 4 : A schematic structural diagram of a fatigue-resistant FRP anchoring device according to the fourth embodiment of the present invention; Figure 5 : A schematic structural diagram of a fatigue-resistant FRP anchoring device according to the present invention described in Example 5; In the above drawings, the descriptions of the reference numerals are as follows: 1- Anchor, 101-anchor sleeve, 102-working nut, 103-integral composite anchor, 2- Pressure sensor, 3- Vector pad, 4-anchor plate, 5-FRP cable body. DETAILED DESCRIPTION Embodiment 1

[0026] A fatigue-resistant FRP anchoring device for a tensioning end comprises an anchor 1, a vector pad 3, and an anchor pad 4 which are tightly connected in sequence, wherein: The anchor 1 comprises an anchor sleeve 101 and a working nut 102. The anchor sleeve 101 is anchored on the FRP cable body 5 composed of FRP composite tendons. The working nut 102 is connected to the anchor sleeve 101 by threads. The lower end face of the working nut 102 is an outer spherical end.

[0027] The vector pad 3 is a circular double-spherical steel pad, the upper end face of the vector pad 3 is an upper inner spherical surface, and the lower end face of the vector pad 3 is a lower outer spherical surface. The radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface; the upper inner spherical surface of the vector pad 3 and the spherical end of the working nut 102 form a spherical pair, and the vector pad 3 and the working nut 102 are directly connected through the spherical pair.

[0028] The anchor plate 4 is a square steel plate with an inner spherical surface on one side. The inner spherical surface of the anchor plate 4 and the lower outer spherical surface of the vector plate 3 form a spherical pair, and the anchor plate 4 and the vector plate 3 are directly connected through the spherical pair.

[0029] The spherical centers of the spherical pair between the vector pad 3 and the working nut 102 are in the same direction; the spherical centers of the spherical pair between the anchor pad 4 and the vector pad 3 are in the same direction. Embodiment 2

[0030] A fatigue-resistant FRP anchoring device for tensioning ends, the difference between the device and the first embodiment is that a pressure sensor 2 is also installed between the vector pad 3 and the anchor 1. The specific structure of the device is as follows: A fatigue-resistant FRP anchoring device for a tensioning end comprises an anchor 1, a pressure sensor 2, a vector pad 3, and an anchor pad 4 which are tightly connected in sequence, wherein: The anchor 1 comprises an anchor sleeve 101 and a working nut 102. The anchor sleeve 101 is anchored on the FRP cable body 5 composed of FRP composite tendons. The working nut 102 is connected to the anchor sleeve 101 by threads. Both ends of the working nut 102 are straight end faces.

[0031] The pressure sensor 2 is a graphene composite elastomer, the graphene composite material is a graphene-polymer composite material, the pressure sensor 2 is a ring-shaped spherical pad, the upper end of the pressure sensor 2 is a flat end, and the lower end is an outer spherical end; the straight end face of the working nut 102 is pressed on the flat end of the pressure sensor 2.

[0032] The vector pad 3 is a circular double-spherical steel pad, the upper end surface of the vector pad 3 is an upper inner spherical surface, and the lower end surface of the vector pad 3 is a lower outer spherical surface. The radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface; the upper inner spherical surface of the vector pad 3 and the outer spherical end of the pressure sensor 2 form a spherical pair, and the vector pad 3 and the pressure sensor 2 are connected through the spherical pair.

[0033] The anchor plate 4 is a square steel plate with an inner spherical surface on one side. The inner spherical surface of the anchor plate 4 and the lower outer spherical surface of the vector plate 3 form a spherical pair, and the anchor plate 4 and the vector plate 3 are directly connected through the spherical pair.

[0034] The spherical centers of the spherical pair between the vector pad 3 and the pressure sensor 2 are in the same direction; the spherical centers of the spherical pair between the anchor pad 4 and the vector pad 3 are in the same direction, so that the axis between the FRP cable body 5 and the anchor 1 can achieve the consistency effect of adjusting in the same direction. Embodiment 3

[0035] A fatigue-resistant FRP anchoring device for a fixed end, comprising an anchor 1, a vector pad 3, and an anchor pad 4 which are tightly connected in sequence, wherein: The anchor 1 comprises an anchor sleeve 101 and a working nut 102. The anchor sleeve 101 is anchored on the FRP cable body 5 composed of FRP composite tendons. The working nut 102 is connected to the anchor sleeve 101 by threads. The upper end face of the working nut 102 is an inner spherical end.

[0036] The vector pad 3 is a circular double-spherical steel pad, the upper end face of the vector pad 3 is an upper inner spherical surface, and the lower end face of the vector pad 3 is a lower outer spherical surface. The radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface; the lower outer spherical surface of the vector pad 3 and the inner spherical end of the working nut 102 form a spherical pair, and the vector pad 3 and the working nut 102 are directly connected through the spherical pair.

[0037] The anchor plate 4 is a square steel plate with an outer spherical surface on one side. The outer spherical surface of the anchor plate 4 and the upper inner spherical surface of the vector plate 3 form a spherical pair, and the anchor plate 4 and the vector plate 3 are directly connected through the spherical pair.

[0038] The spherical centers of the spherical pair between the vector pad 3 and the working nut 102 are in the same direction; the spherical centers of the spherical pair between the anchor pad 4 and the vector pad 3 are in the same direction, so that the axes between the FRP cable body 5 and the anchor 1 can achieve the consistency effect of adjusting in the same direction. Embodiment 4

[0039] A fatigue-resistant FRP anchoring device for a fixed end, comprising an anchor 1, a pressure sensor 2, a vector pad 3, and an anchor pad 4 which are tightly connected in sequence, wherein: The anchor 1 comprises an anchor sleeve 101 and a working nut 102. The anchor sleeve 101 is anchored on the FRP cable body 5 composed of FRP composite tendons. The working nut 102 is connected to the anchor sleeve 101 by threads. Both ends of the working nut 102 are straight end faces.

[0040] The pressure sensor 2 is a graphene composite elastomer, the graphene composite material is a graphene-polymer composite material, the pressure sensor 2 is a ring-shaped spherical pad, the upper end of the pressure sensor 2 is the inner spherical end, and the lower end is the plane end; the straight end face of the working nut 102 is pressed on the plane end of the pressure sensor 2.

[0041] The vector pad 3 is a circular double-spherical steel pad, the upper end surface of the vector pad 3 is an upper inner spherical surface, and the lower end surface of the vector pad 3 is a lower outer spherical surface. The radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface; the lower outer spherical surface of the vector pad 3 and the inner spherical end of the pressure sensor 2 form a spherical pair, and the vector pad 3 and the pressure sensor 2 are connected through the spherical pair.

[0042] The anchor plate 4 is a square steel plate with an outer spherical surface on one side. The outer spherical surface of the anchor plate 4 and the upper inner spherical surface of the vector plate 3 form a spherical pair, and the anchor plate 4 and the vector plate 3 are directly connected through the spherical pair.

[0043] The spherical centers of the spherical pair between the vector pad 3 and the working nut 102 are in the same direction; the spherical centers of the spherical pair between the anchor pad 4 and the vector pad 3 are in the same direction, so that the axes between the FRP cable body 5 and the anchor 1 can achieve the consistency effect of adjusting in the same direction. Embodiment 5

[0044] A fatigue-resistant FRP anchoring device for a fixed end, comprising an anchor 1, a pressure sensor 2, a vector pad 3, and an anchor pad 4 which are tightly connected in sequence, wherein: The anchor 1 includes an integral composite anchor 103, which is an integral composite bonding anchor such as a cold cast filament bonding type or a filament extrusion bonding type. The integral composite anchor 103 is anchored on a FRP cable body 5 composed of FRP composite tendons. Both ends of the integral composite anchor 103 are straight end faces. The integral composite anchor 103 is directly pressed flat on the plane end of the pressure sensor 2.

[0045] The pressure sensor 2 is a graphene composite elastomer, the graphene composite material is a graphene-polymer composite material, the pressure sensor 2 is a circular spherical pad, the upper end of the pressure sensor 2 is the inner spherical end, and the lower end is the plane end; the straight end face of the integral composite anchor 103 is pressed on the plane end of the pressure sensor 2.

[0046] The vector pad 3 is a circular double-spherical steel pad, the upper end face of the vector pad 3 is an upper inner spherical surface, and the lower end face of the vector pad 3 is a lower outer spherical surface. The radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface; the lower outer spherical surface of the vector pad 3 and the inner spherical end of the pressure sensor 2 form a spherical pair, and the vector pad 3 and the integral composite anchor 103 are directly connected through the spherical pair.

[0047] The anchor plate 4 is a square steel plate with an outer spherical surface on one side. The outer spherical surface of the anchor plate 4 and the upper inner spherical surface of the vector plate 3 form a spherical pair, and the anchor plate 4 and the vector plate 3 are directly connected through the spherical pair.

[0048] The spherical centers of the spherical pair between the vector pad 3 and the working nut 102 are in the same direction; the spherical centers of the spherical pair between the anchor pad 4 and the vector pad 3 are in the same direction, so that the axes between the FRP cable body 5 and the anchor 1 can achieve the consistency effect of adjusting in the same direction.

[0049] The anchor sleeve 101, the working nut 102, the integral composite anchor 103 and the FRP cable body in the above-mentioned anchor 1 are all prior arts, and their specific structures will not be described in detail here.

[0050] Now, the FRP anchoring device suitable for fatigue resistance described in Example 2 is used as the tensioning end, and the FRP anchoring device suitable for fatigue resistance described in Example 4 is used as the fixed end. The installation process of the FRP cable is as follows: (1) Pre-embed the anchor plate 4; (2) preparing the FRP cable body 5 and the anchor 101; (3) Insert the FRP cable body 5 and the anchor 101 into the embedded holes at the fixed end and the tensioning end respectively; (4) Install the vector pad 3 and the pressure sensor 2 at the fixed end in sequence, anchor the anchor 101 to the FRP cable body 5 at the fixed end, and then tighten the working nut 102 on the anchor 101; (5) Install the vector pad 3 and the pressure sensor 2 in sequence at the tensioning end, and preliminarily tighten the working nut 102 on the anchor 101; (6) Install the tensioning assembly, perform tensioning operations on the FRP cable body 5, and record relevant data; (7) After tensioning to the designed cable force, tighten the working nut 102 at the tensioning end again and measure the data of the pressure sensors at both ends.

[0051] (8) The pressure sensors 2 at both ends monitor the cable force data of the FRP cable body 5 in service and upload it to the data center in real time.

Claims

1. A fatigue-resistant FRP anchoring device, comprising an anchor (1) and an anchor pad (4), wherein the anchor (1) is anchored on an FRP cable body (5), and is characterized in that: A vector pad (3) is also installed between the anchor (1) and the anchor pad (4); the vector pad (3) is a circular double-spherical steel pad; the vector pad (3) and the anchor pad (4) are directly connected via a spherical pair; and the vector pad (3) and the anchor (1) are directly or indirectly connected via a spherical pair.

2. A fatigue-resistant FRP anchoring device according to claim 1, characterized in that: The anchor (1) and the vector pad (3) are directly connected via a spherical pair.

3. A fatigue-resistant FRP anchoring device according to claim 2, characterized in that: The anchor (1) comprises an anchor sleeve (101) and a working nut (102); the anchor sleeve (101) is anchored on the FRP cable body (5); the working nut (102) is connected to the anchor sleeve (101) via a thread; one end of the working nut (102) is a spherical end, and the spherical end is directly connected to the vector pad (3) via a spherical pair.

4. A fatigue-resistant FRP anchoring device according to claim 2, characterized in that: The anchor (1) comprises an integral composite anchor (103), one end of the integral composite anchor (103) being a spherical end, and the spherical end being directly connected to the vector pad (3) via a spherical pair.

5. The fatigue-resistant FRP anchoring device according to claim 1, characterized in that: A pressure sensor (2) is also installed between the vector pad (3) and the anchor (1); one end of the pressure sensor (2) is a plane end and the other end is a spherical end; the end surface of the anchor (1) in contact with the pressure sensor (2) is a straight end surface, which is directly pressed on the plane end of the pressure sensor (2); the spherical end of the pressure sensor (2) is connected to the vector pad via a spherical pair.

6. A fatigue-resistant FRP anchoring device according to claim 5, characterized in that: The anchor (1) comprises an anchor sleeve (101) and a working nut (102); the anchor sleeve (101) is anchored on the FRP cable body (5); the working nut (102) is connected to the anchor sleeve (101) via threads; both ends of the working nut (102) are straight end faces; the straight end face of the working nut (102) is directly pressed against the flat end of the pressure sensor (2).

7. The fatigue-resistant FRP anchoring device according to claim 5, characterized in that: The anchor (1) comprises an integral composite anchor (103), both ends of the integral composite anchor (103) being straight end surfaces, and the integral composite anchor (103) is directly pressed flat on the plane end of the pressure sensor (2).

8. A fatigue-resistant FRP anchoring device according to any one of claims 1 to 7, characterized in that: The upper end surface of the vector pad (3) is an upper inner spherical surface, and the lower end surface of the vector pad (3) is a lower outer spherical surface. The radii of the upper inner spherical surface and the lower outer spherical surface are different, and the radius of the upper inner spherical surface is greater than the radius of the lower outer spherical surface.

9. A fatigue-resistant FRP anchoring device according to claim 8, characterized in that: The spherical centers of the spherical pairs are all in the same direction.

10. A fatigue-resistant FRP anchoring device according to claim 5, characterized in that: The pressure sensor (2) is a graphene composite material elastomer.

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