JP6764168B2 - End fixing structure of fiber reinforced plastic cable and fiber reinforced plastic cable equipped with this - Google Patents

Description

The present invention relates to a fiber reinforced plastic cable terminal fixing structure used for mooring ropes, cable-stayed bridges, suspension bridges and other bridges, and other buildings, and a fiber reinforced plastic cable having this terminal fixing structure.

Cables made using FRP (Fiber Reinforced Plastics) (fiber reinforced plastics) composed of a composite material of fibers (synthetic fibers) and plastics are lighter, more corrosion resistant, and non-corrosion resistant than steel cables of the same diameter. Has excellent properties such as magnetism. Carbon fibers, glass fibers, aramid fibers and the like are used as fibers used for FRP, and epoxy resins, polyamide resins, phenol resins and the like are used as plastics used for FRP.

FRP cables have the same high strength as steel cables in terms of tensile strength in the longitudinal direction, but are weak in terms of local shearing force and surface scratches. For this reason, if the wedge is directly bitten and the socket is fixed to the end of the wedge in the same way as a steel cable, cutting due to shear fracture and slippage due to surface fracture occur, resulting in high fixing efficiency between the cable end and the socket. I can't get it.

Patent Document 1 describes a socket in which an end portion of an FRP cable is inserted and an epoxy resin is filled and cured to fix the socket to the terminal portion of the FRP cable. However, when a very large tensile force is applied to the FRP cable, a fixing force even larger than the fixing force exerted by the epoxy resin may be required.

Japanese Unexamined Patent Publication No. 9-209501

An object of the present invention is to provide a terminal fixing structure suitable for a fiber reinforced plastic cable to which a very large tensile force is applied.

The terminal fixing structure according to the present invention is a structure for fixing the terminal socket to the end portion of the fiber reinforced plastic cable. A fiber reinforced plastic cable is a fiber bundle formed by impregnating a large number of synthetic fibers such as carbon fibers and glass fibers with a resin material such as epoxy resin, polyamide resin, and phenol resin, and curing the above resin. It is formed by further bundling a plurality of fiber bundles made of fiber reinforced plastic.

The terminal fixing structure of the fiber reinforced plastic cable according to the present invention is a fiber reinforced plastic cable in which a plurality of resin-impregnated fiber bundles are bundled from one opening of a terminal socket having a hollow inside and both ends open. The end portion is inserted into the terminal socket, and the end portion of the fiber reinforced plastic cable is separated into a fiber bundle in the terminal socket, and the expansion agent filled in the terminal socket is separated by the above. It is characterized in that a plurality of the resulting fiber bundles are embedded.

As the material of the terminal socket, iron or an iron-based alloy, or a carbon rope such as S45C can be used. Further, in a seawater environment or the like, stainless steel such as SUS304 or SUS316 may be used. The materials are not particularly limited as long as they meet the required strength and durability.

The leavening agent is, for example, a liquid or slurry in the initial state, and is a resin or concrete that expands in volume in the process of hardening (solidification). Ready-mixed concrete containing a large amount of leavening agent for preventing molding shrinkage, or a lime-based static crushing agent used at the time of breaking a concrete structure or the like can also be used as a leavening agent to be filled in the terminal socket. Also, when the terminal socket is made of iron or an iron-based alloy, it is preferable to use a basic leavening agent. Internal corrosion of the terminal socket is prevented, making it suitable for use in seawater or high humidity environments such as marine structures.

According to the present invention, since the end portion of the fiber reinforced plastic cable in the terminal socket is separated into fiber bundles, a leavening agent is filled between each of the plurality of fiber bundles in the terminal socket, and a plurality of leavening agents are contained therein. Each of the fiber bundles of the book is embedded. The expansion pressure generated by the expansion of the leavening agent in the terminal socket exerts a large binding force on each of the disassembled fiber bundles. The terminal socket can be firmly fixed (fixed) to the end portion of the fiber reinforced plastic cable. Since the fiber bundle is a bundle of a large number of fibers (synthetic fibers), it has a fine uneven structure on its surface, and this uneven structure also contributes to the improvement of the binding force of the fiber bundle.

A cylindrical or conical trapezoidal hollow is formed inside the terminal socket. In one embodiment, the terminal socket has a cylindrical hollow, and the end portion of the fiber reinforced plastic cable is inserted into the terminal socket through one opening. In another embodiment, the terminal socket has a conical trapezoidal hollow, and the end portion of the fiber reinforced plastic cable is inserted into the terminal socket through a small diameter opening.

As described above, the expansion pressure generated by the expansion of the leavening agent in the terminal socket firmly fixes (fixes) the terminal socket to the end portion of the fiber reinforced plastic cable. In particular, when a conical trapezoidal hollow is adopted, the expansion pressure acting by the expansion of the leavening agent creates a component force in the direction of pulling the fiber reinforced plastic cable into the terminal socket, so the fiber reinforced plastic cable is pulled from the terminal socket. It can be difficult to pull out and the fixing efficiency is improved. Since it is not necessary to increase the length of the terminal socket (the length of the end of the fiber reinforced plastic cable that is inserted into the terminal socket and embedded in the leavening agent) in order to improve the fixing efficiency, a conical trapezoidal hollow is used. By adopting it, the length of the terminal socket can be shortened. The hollow slope angle of the conical trapezoid is preferably designed to be 6.0 ° to 12.0 °.

Preferably, the opening at the tip of the terminal socket is closed by the lid member. The leavening agent is prevented from leaking through the tip opening of the terminal socket.

The lid member is often made of the same or the same material as the terminal socket, and is screwed to, for example, the tip of the terminal socket. The lid member can be firmly fixed to the terminal socket. After injecting the leavening agent into the terminal socket, the lid member may be screwed in before the leavening agent hardens. It is possible to maintain the internal pressure in the terminal socket caused by the expansion of the leavening agent, and the internal pressure applies a force to the screw portion to prevent the lid member from falling off due to loosening of the screw. Furthermore, since the leavening agent does not come into contact with the atmosphere or seawater, it is possible to prevent deterioration due to carbon dioxide existing in the atmosphere and deterioration due to elution of alkaline components in the sea, especially when a basic leavening agent is used. ..

In one embodiment, a sealing material is packed in the opening at the end of the terminal socket. Leakage of leavening agent from the opening at the end of the terminal socket is also prevented.

The ends of the fiber-reinforced plastic cables need to be separated into fiber bundles, preferably one of each of the separated fiber bundles is passed through a spacer hole provided in the terminal socket. ing. In the terminal socket, it is possible to secure a gap for the leavening agent to enter between the separated fiber bundles. More preferably, the spacer holes are formed at equal intervals, so that it is possible to secure equidistant gaps between the separated fiber bundles. Each of the disassembled fiber bundles can be strongly restrained.

The terminal fixing structure described above is provided at at least one of both end portions of the fiber reinforced plastic cable. The present invention also provides a fiber reinforced plastic cable having the terminal fixing structure described above at at least one of both end portions. The fiber-reinforced plastic cable according to the present invention makes it difficult for the end portion of the fiber-reinforced plastic cable to come out from the terminal socket even when a large tensile force is applied. For example, a fiber reinforced plastic cable that can withstand a very large tensile force of about 20,000 kN to 36,000 kN is realized.

In one embodiment, a plurality of fiber bundles are twisted together at a low angle, eg, a twist angle of 3.0 ° to 4.0 °. By twisting a plurality of fiber bundles so as to have a structure similar to that of a parallel wire cable, the tensile strength per unit area of the fiber reinforced plastic cable can be increased.

The floating offshore platform is shown schematically. The end part of the tendon is shown enlarged. It is an exploded sectional view of the terminal part of the tendon. FIG. 3 is an enlarged cross-sectional view taken along the line IV-IV of FIG. It is an enlarged front view of a spacer. The manufacturing process of the terminal fixing structure is shown. The manufacturing process of the terminal fixing structure is shown. It is an exploded sectional view of the terminal part of the tendon of the modification. It is sectional drawing of the terminal part of the tendon of another Example.

FIG. 1 schematically shows a floating offshore platform.

Platform 1 shown in FIG. 1 is called a tension leg platform (TLP), and a floating structure that is forcibly semi-submerged and a foundation placed on the seabed are connected by a mooring cable called a tendon. ， It is an offshore platform for mooring a floating structure by utilizing the tension generated in the tendon by the buoyancy of the floating structure.

The floating structure of the TLP 1 includes four vertical columns 2 vertically arranged at positions corresponding to the four corners of the square, and a horizontal member 3 fixed inside the lower ends of each of the four vertical columns 2. It has. The four vertical columns 2 and the horizontal members 3 are all hollow, which causes a large buoyancy in the floating structure. A deck 4 is installed at the upper end of the four vertical columns 2, and various production facilities such as a drilling rig 9 are provided on the deck 4.

A tendon support 5 is fixed to the outside of each lower end of each of the four vertical columns 2. The upper end of the tendon 10 is fixed to the tendon support 5, and the lower end is fixed to the foundation 8 placed on the seabed. An upward force acts on the floating structure due to buoyancy, and a downward force of the same magnitude as that force acts on the tendon 10, so that the vertical force is balanced. When a strong force acts on the tendon 10 in the vertical direction, the TLP1 is less swayed and can maintain a stable posture even under bad weather sea conditions such as a typhoon.

A riser 6 is installed from the deck 4 to the well head 7 installed on the seabed, and drilling of the seabed bedrock, excavation of oil, gas, etc. are performed through the riser 6.

FIG. 2 shows an enlarged end portion of the tendon 10. FIG. 3 is an exploded cross-sectional view of the terminal portion of the tendon 10. FIG. 4 is an enlarged cross-sectional view of the carbon fiber cable along the IV-IV line of FIG.

The tendon 10 includes a carbon fiber cable 13, a terminal socket 11 fixed (fixed) to the end portion of the carbon fiber cable 13, and a lid 12 fixed to the tip end portion of the terminal socket 11. The terminal socket 11 is made of metal (for example, iron, iron-based alloy, carbon steel, stainless steel, nickel chrome steel, chrome molybdenum steel, etc.) and has a columnar outer shape. The inside of the terminal socket 11 is hollow, and a conical trapezoidal space 11a is formed in the central portion thereof, and a large-diameter cylindrical space 11b and a small-diameter cylindrical space 11c are connected to both ends thereof. Hereinafter, the end portion of the terminal socket 11 in which the large-diameter cylindrical space 11b is formed is referred to as a tip portion, and the end portion in which the small-diameter cylindrical space 11b on the opposite side is formed is referred to as an end portion. The lengths of the large-diameter and small-diameter cylindrical spaces 11b and 11c at both ends thereof are shorter than the length of the conical trapezoidal space 11a, and most of the hollow of the terminal socket 11 is occupied by the conical trapezoidal space 11a. The outer shape of the terminal socket 11 does not necessarily have to be cylindrical, and may have, for example, the outer shape of a polygonal prism. The gradient angle of the conical trapezoidal space 11a is about 6.0 ° to 12.0 °. The conical trapezoidal space 11a shown in FIG. 3 has a gradient angle of about 8.0 °.

With reference to FIG. 4, a plurality of carbon fiber cables 13 are densely bundled with 91 carbon fiber bundles 14 having a circular cross section. The surface of the carbon fiber cable 13 outside the terminal socket 11 is preferably coated with high density polyethylene (not shown). The diameter and number of carbon fiber bundles 14 are appropriately adjusted according to the tensile strength required for the tendon 10, and the size of the terminal socket 11 and the hollow size in the terminal socket 11 are also adjusted to the tensile strength required for the tendon 10. It will be adjusted accordingly. Each of the carbon fiber bundles 14 is formed by impregnating hundreds of thousands of thin carbon fiber filaments, for example, about 100,000 to 700,000, with an epoxy resin, twisting them, and curing the epoxy resin. It is made of Carbon Fiber Reinforced Plastics (CFRP). A large number of carbon fiber filaments may be bundled without being twisted. In any case, the surface of the carbon fiber bundle 14 has a fine uneven structure formed by bundling a large number of carbon fiber filaments. The carbon fiber cable 13 formed by bundling the carbon fiber bundles 14 has a diagonal length in a cross section of, for example, about 100 mm to 180 mm.

A plurality of carbon fiber bundles 14 are twisted at a low twist angle of about 3.0 ° to 4.0 ° to form a carbon fiber cable 13, and the carbon fiber cable 13 is formed from a stranded cable. Has a structure similar to a parallel wire cable. In FIGS. 2 and 3, the twist angles of the plurality of carbon fiber bundles 14 are slightly emphasized for the sake of clarity.

When the carbon fiber cable 13 having the structure of the parallel wire cable is viewed from the cross section with reference to FIG. 4, its outer shape (outer edge) has a regular hexagonal shape. The carbon fiber cable 13 having the structure of a parallel wire cable has no decrease in strength due to twisting as compared with a stranded wire cable, and is suitable for use as a tendon 10. In addition, by twisting a plurality of carbon fiber bundles 14 with a low twist angle, the carbon fiber cable 13 can be wound around a reel without losing its shape while maintaining high tensile strength per unit area. Become.

With reference to FIG. 3, the end portion of the carbon fiber cable 13 is inserted into the terminal socket 11 and separated into carbon fiber bundles 14 inside the terminal socket 11. Each of the plurality of separated carbon fiber bundles 14 is passed through a plurality of holes 21 formed in the spacer 20 provided inside the terminal socket 11 one by one.

FIG. 5 is an enlarged front view showing the appearance of the spacer 20. The spacer 20 is made of metal or plastic and has a circular outer shape when viewed from the front. The diameter of the spacer 20 is slightly smaller than the diameter of the large-diameter cylindrical space 11b of the terminal socket 11, and the wall thickness of the spacer 20 is substantially equal to the length of the large-diameter cylindrical space 11b. The spacer 20 is completely fitted in the large-diameter cylindrical space 11b of the terminal socket 11.

The spacer 20 is provided with holes 21 having the same number of holes 21 as the number of the plurality of carbon fiber bundles 14 constituting the carbon fiber cable 13 at equal intervals, and the arrangement of the plurality of holes 21 constitutes the carbon fiber cable 13. It is aligned with the arrangement of the carbon fiber bundle 14. Therefore, if the outermost holes 21 among the plurality of holes 21 formed in the spacer 20 are connected by a straight line, a regular hexagon having the same cross-sectional shape as that of the carbon fiber cable 13 is obtained.

As described above, one loosened carbon fiber bundle 14 is passed through each of the holes 21 of the spacer 20, whereby a large-diameter columnar shape is formed between the adjacent carbon fiber bundles 14 in the conical trapezoidal space 11a. Equally spaced gaps that spread toward the space 11b are secured.

The expansion agent 30 is filled in the internal space of the terminal socket 11, and the loosened carbon fiber bundle 14 is embedded in the expansion agent 30 in the terminal socket 11. Although not shown, the leavening agent 30 may also enter a slight gap between the spacer 20 and the inner surface of the terminal socket 11 in the cylindrical space 11b. The leavening agent 30 produces moderate expansion under appropriate temperature control. Since the frictional force is increased by the expansion pressure generated by the expansion of the leavening agent 30, the binding force of the carbon fiber bundle 14 in the terminal socket 11 is enhanced. The uneven structure on the surface of the carbon fiber bundle 14 also contributes to the improvement of the binding force. Further, since the spacer 20 provides a space between the adjacent carbon fiber bundles 14, the binding force of the swelling agent 30 acts on each of the carbon fiber bundles 14, whereby the carbon fiber bundle 14 (carbon) The end portion of the fiber cable 13) is very difficult to pull out from the terminal socket 11. As the leavening agent 30, for example, one containing calcium oxide as a main component and which expands by reacting with water can be used.

When the leavening agent 30 filled in the terminal socket 11 expands, the terminal socket 11 is pushed outward by the expansion pressure. The material, wall thickness, etc. of the terminal socket 11 are designed so that the terminal socket 11 is not deformed by the expansion pressure.

Since the internal space of the terminal socket 11 is conical trapezoidal, when the leavening agent 30 expands and the expansion pressure acts outward, a component force is generated in the direction of pulling the carbon fiber cable 13 into the terminal socket 11. This makes it difficult for the carbon fiber cable 13 to come out of the terminal socket 11, and high fixing efficiency is achieved. Even if a large tensile force is applied to the tendon 10, the end portion of the carbon fiber cable 13 does not come out from the terminal socket 11, and as a result, the tendon 10 has a very large tensile force of about 20,000 kN to 36,000 kN. It can be tolerable. This enables the installation of TLP1 in ultra-deep waters exceeding 16,000 m, such as the Gulf of Mexico, off Brazil, and off West Africa. It is also necessary to make the length of the terminal socket 11 (the length of the end portion of the carbon fiber cable 13 inserted into the terminal socket 11 and embedded in the leavening agent 30) longer than necessary in order to improve the fixing efficiency. It disappears.

A male screw 11d is formed on the outer peripheral surface of the tip portion of the terminal socket 11 having a large-diameter cylindrical space 11b, and a lid 12 having a female screw 12a formed on the inner peripheral surface is screw-coupled to the male screw 11d. The lid 12 is firmly fixed to the tip of the terminal socket 11, and the opening of the large-diameter cylindrical space 11b is closed by the lid 12. The expanded leavening agent 30 does not leak out through the opening of the large-diameter cylindrical space 11b of the terminal socket 11. Further, even if the spacer 20 is pushed by the expansion pressure, the spacer 20 does not come out from the opening of the cylindrical space 11b.

Further, the small-diameter cylindrical space 11c at the end of the terminal socket 11 is filled with a sealing material (for example, epoxy resin) 40, and a leavening agent that expands from the opening of the small-diameter cylindrical space 11c of the terminal socket 11 30 never leaks.

6 and 7 show the manufacturing process of the terminal fixing structure.

With reference to FIG. 6, the end portion of the carbon fiber cable 13 is inserted into the terminal socket 11 through the opening of the small-diameter cylindrical space 11c of the terminal socket 11, and through the opening of the large-diameter cylindrical space 11b of the terminal socket 11. Get out. With reference to FIG. 7, the end portion of the carbon fiber cable 13 protruding from the opening of the large-diameter cylindrical space 11b of the terminal socket 11 is loosened into carbon fiber bundles 14, and each of the carbon fiber bundles 14 is spacerd 20. Pass one by one through the holes 21 of. By moving the terminal socket 11 to the end portion of the carbon fiber cable 13, the end portion (unraveled carbon fiber bundle 14) of the carbon fiber cable 13 is drawn into the conical trapezoidal space 11a of the terminal socket 11, and the spacer 20 is It is fitted into the large-diameter cylindrical space 11b of the terminal socket 11. By screwing the lid 12 to the tip of the terminal socket 11, the opening of the large-diameter cylindrical space 11b of the terminal socket 11 is closed.

The terminal socket 11 is erected vertically, and the conical trapezoidal space 11a is filled with a swelling agent 30 mixed with water through the opening of the small-diameter cylindrical space 11c (the gap between the inner surface of the cylindrical space 11c and the carbon fiber cable 13). Finally, the sealing material 40 is filled in the gap of the cylindrical space 11c.

After a predetermined time, the leavening agent 30 solidifies and then swelling develops. Expansion pressure is applied to the inside of the terminal socket 11. The loosened carbon fiber bundle 14 is strongly restrained in the terminal socket 11 by the expansion pressure, whereby the terminal socket 11 is strongly fixed at the end portion of the carbon fiber cable 13.

FIG. 8 shows a modified example, in which the male screw 12b is formed on the lid 12A and the female screw 11e is formed on the inner surface of the large-diameter cylindrical space 11b of the terminal socket 11A. Different from terminal socket 11. By screwing the male screw 12b of the lid 12A and the female screw 11e of the terminal socket 11A, the lid 12A is firmly fixed to the tip of the terminal socket 11A, and the opening of the large-diameter cylindrical space 11b is closed. ..

FIG. 9 shows another embodiment, and shows a cross-sectional view of a terminal portion of a tendon corresponding to FIG.

The terminal socket 11B is longer than the terminal sockets 11 and 11A described above, and a cylindrical space 11f is formed inside the terminal socket 11B over the entire length of the terminal socket 11B. The leavening agent 30 is filled in the cylindrical space 11f, and the loosened carbon fiber bundle 14 is embedded in the filled leavening agent 30.

Two spacers 20A and 20B are fitted in the cylindrical space 11f at intervals. One spacer 20A is near the tip of the terminal socket 11B, and the other spacer 20B is near the end of the terminal socket 11B. It is located in each. The spacers 20A and 20B are also provided with a plurality of holes as many as the number of the loosened carbon fiber bundles 14, and one carbon fiber bundle 14 is passed through each of the plurality of holes. Since the expansion agent 30 fills the gap between the carbon fiber bundles 14 secured by the spacers 20A and 20B, the carbon fiber bundle 14 (the end portion of the carbon fiber cable 13) can be strongly restrained in the terminal socket 11B. The terminal socket 11B can be firmly fixed to the end portion of the carbon fiber cable 13. A lid (not shown) is fixed to the tip of the terminal socket 11B by using a female screw 15a formed on the inner surface of the tip of the cylindrical space 11f, and the cylindrical space 11f at the tip of the terminal socket 11B is fixed by the lid. The opening is closed.

The terminal sockets 11, 11A, and 11B described above may be fixed to both end portions of the carbon fiber cable 13. In addition, the carbon fiber cable in which the terminal socket is fixed at one end or both ends is not limited to the use as a tendon (mooring rope) 10, but is not limited to the use as a cable-stayed bridge, a suspension bridge, or other bridge, a suspension roof, or other construction. It can also be used for things.

In the above-described embodiment, the example of using the carbon fiber cable 13 in which a plurality of carbon fiber bundles 14 are bundled has been described, but glass fiber, aramid fiber or other synthetic fiber may be used instead of the carbon fiber. As for the resin impregnated in the carbon fiber bundle 14, a polyamide resin, a phenol resin or other resin may be used instead of the epoxy resin.

1 platform
10 Tendon
11, 11A, 11B terminal socket
11a Conical trapezoidal space
11b, 11c, 11f Cylindrical space
11d, 12b, 15a male screw
11e, 12a Female screw
12, 12A lid
13 carbon fiber cable
14 Carbon fiber bundle
20, 20A, 20B spacer
21 holes
40 Encapsulant

Claims (8)

The end portion of a fiber reinforced plastic cable in which a plurality of resin-impregnated fiber bundles are bundled is inserted into the terminal socket through a small-diameter opening of a terminal socket having a conical trapezoidal hollow inside and both ends open. Cone,
In the terminal socket, the end portion of the fiber reinforced plastic cable is separated into a fiber bundle.
The expansivity agent filled in the terminal socket, the fiber bundle of a plurality of which Barasa above is embedded,
The large-diameter opening of the terminal socket is closed by a lid member that is firmly fixed to the large-diameter opening.
End fixing structure of fiber reinforced plastic cable. Frustoconical hollow has a slope angle of 6.0 ° to 12.0 °, the terminal fixing structure of the fiber-reinforced plastic cable according to claim 1. The lid member is screwed to the large-diameter opening of the terminal socket.
The terminal fixing structure of the fiber reinforced plastic cable according to claim 1 or 2 . A sealing material is packed in the small diameter opening of the terminal socket.
The terminal fixing structure of the fiber reinforced plastic cable according to any one of claims 1 to 3 . Each of the disassembled fiber bundles is passed through the spacer holes provided in the terminal socket one by one.
The terminal fixing structure of the fiber reinforced plastic cable according to any one of claims 1 to 4 . The terminal fixing structure according to any one of claims 1 to 5 is provided at least one of both end portions.
Fiber reinforced plastic cable. Multiple fiber bundles are twisted together with a low twist angle,
The fiber reinforced plastic cable according to claim 6 . The above fiber bundle is a carbon fiber bundle,
The fiber reinforced plastic cable according to claim 6 or 7 .

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