JP4443796B2 - Water tube reinforcement method, water tube reinforcement member, fiber reinforced resin for water tube reinforcement - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for reinforcing a hydraulic pipe and the like, and more particularly, to a method for reinforcing a hydraulic pipe and the like that greatly reduce field work.
[0002]
[Prior art]
Fiber Reinforced Plastics (FRP: Fiber Reinforced Plastics) using reinforced fibers such as carbon, glass, and aramid are widely used in various sporting goods and aircraft industries, taking advantage of their high strength and light weight. Yes. In recent years, in the construction field, for example, application of carbon fiber reinforced resin (CFRP) has been attempted as a reinforcing material for piers, subway middle columns, reinforced concrete structure columns, and the like. For example, Japanese Patent Application Laid-Open No. 10-280706 discloses a technique for reinforcing reinforcement by attaching a carbon fiber sheet to a separation portion between two reinforcing steel plates provided on a pillar of a structure.
[0003]
On the other hand, in a hydroelectric power station currently operating in Japan, a hydraulic iron pipe is widely used as a hydraulic pipe. As a typical damage mode of a hydraulic iron pipe, there is a reduction in the thickness of the pipe body due to corrosion and wear, but there are cases where a hydraulic iron pipe with a surplus thickness has already been used, and the establishment of a life extension method has been established. It is strongly desired. In the past, when the hydraulic iron pipes were aging, replacements were often made. However, in recent years, the power business environment has been severe due to the sluggish growth in power demand and the liberalization of the power market. Operators are demanding a method for extending the life with a shorter construction period and lower cost.
[0004]
[Problems to be solved by the invention]
Based on this situation, we have a lot of experience in repairing and reinforcing reinforced concrete members, have little weight increase, have excellent corrosion resistance, and use CFRP that can exhibit the same strength as steel pipes. If it can be reinforced in the same way as a member, it can be an effective answer to the demands of electric power companies. Here, as an application of carbon sheet to repair of hydraulic iron pipes, Reference 1 (Electric Power Engineering No.262 1996 Kenji Sakai et al., “Application of Carbon Fiber to Hydraulic Iron Pipe Repair Technology”) describes the surface of hydraulic iron pipes. After the cleaning, the carbon fiber sheet is bonded with an epoxy resin, and the epoxy resin is impregnated and cured from the surface of the carbon fiber sheet to repair the hydraulic iron pipe.
[0005]
However, the repair method shown in Document 1 is the same as the conventional general pier reinforcement, and the sheet is spread and attached at the reinforcement work site, and impregnated with resin and cured (FRP). In this case, it takes time to impregnate the resin, and a curing period is required for each layer of the carbon fiber sheet, so that the construction period at the site is prolonged.
[0006]
Also, unlike the work site of the pier, the site where the hydraulic iron pipe is provided has a poor footing, for example, the iron pipe is inclined in a mountainous area, and its periphery is very narrow. For this reason, the variation becomes large when the fiber sheet is attached, and for example, unevenness of the resin thickness occurs during the impregnation. As a result, the quality as the reinforcing member is extremely deteriorated, and the reinforcing performance is deteriorated.
[0007]
The present invention has been made in order to solve the technical problems as described above, and the purpose of the present invention is to greatly reduce the construction period at the site for the reinforcement work of the hydraulic pipe, which is generally difficult to work. It is to shorten.
Another object is to dramatically improve product quality as a reinforcing member in a hydraulic pipe.
[0008]
[Means for Solving the Problems]
For this purpose, in the present invention, when reinforcing a hydraulic pipe that is difficult to work on-site, an FRP molded product having an already hardened part is manufactured at the factory and provided to the site, so that the field work can be performed. Significantly reduced and provides higher quality reinforcement. That is, the method for reinforcing a hydraulic pipe to which the present invention is applied is a method of using a fiber reinforced resin (FRP) such as a carbon fiber reinforced resin (CFRP) pre-molded according to the shape of a hydraulic pipe (for example, a hydraulic iron pipe) to be reinforced. Using the opening of the fiber reinforced resin, for example, an attachment step of spreading the fiber reinforced resin by the flexibility of the fiber reinforced resin and attaching the fiber reinforced resin to the hydraulic tube, and the hydraulic tube and the fiber reinforced resin before and after the attachment step Apply adhesive or inject filler (adhesive unnecessary) between the adhesive application / filler injection process, and after attaching fiber reinforced resin to this hydraulic pipe, this opening is fiber reinforced resin And a closing step of closing a fiber previously drawn from the end of the wire using a mechanical joint .
[0009]
Here, in the process of attaching the fiber reinforced resin, in addition to the case of spreading using the flexibility of the fiber reinforced resin, the flexible part such as a fiber part or a semi-cured part separately provided in a part of the fiber reinforced resin is used. It is possible to attach using the property.
[0010]
The fiber-reinforced resin may also enhance bonding by adhering a reinforcing member that covers the open mouth portion be overlapped. It is also possible to repeat the attachment and closing a plurality of times and to reinforce with a fiber reinforced resin composed of a plurality of layers.
[0011]
On the other hand, penstock reinforcing member to which the present invention is applied, and the fiber-reinforced resin portion which is previously molded in a shape along the outer periphery of the penstock to be reinforced, provided at an end portion of the fiber-reinforced resin portion, mechanical joint The fiber used at the time of closing is projected from the end of the fiber reinforced resin part, and the fiber reinforced resin part is closed with a closing part that is closed after the fiber reinforced resin part is attached to the hydraulic pipe. It is characterized in that the hydraulic pipe is reinforced against the stress acting on the hydraulic pipe by the closing portion.
[0012]
Moreover, this invention can be grasped | ascertained as a fiber reinforced resin. That is, the fiber reinforced resin for reinforcing the hydraulic pipe to which the present invention is applied is preliminarily molded in a shape along the outer periphery of the hydraulic pipe to be reinforced, and is required to be expanded when attached to the hydraulic pipe. Is a fiber reinforced resin that is closed after the molded portion is attached to the hydraulic pipe, and reinforces the hydraulic pipe against stress acting on the hydraulic pipe, from the end of the fiber reinforced resin The fiber used at the time of closing by the mechanical joint is projected .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a diagram showing an example of an iron pipe structure in which the hydraulic pipe reinforcing method according to the present embodiment is executed. Here, a hydraulic iron pipe provided in a hydroelectric power plant is shown, and is provided on a slope between mountains. In the iron pipe structure in the present embodiment, an iron pipe (hydraulic iron pipe) 1 is supported by a ring girder 2 and has a total length of several hundred meters (for example, about 500 m). The iron pipe 1 is, for example, a pipe corresponding to the material SS34, a plate thickness of about 9 mm (for example, 6.3 mm to 11.1 mm), and an inner diameter of 1.5 m to 2 m, and the length between the ring girders 2 is 10 m to It is about 20m.
[0014]
Internal pressure acts on the hydraulic iron pipe used for hydroelectric power generation, and distortion occurs in the circumferential direction and the pipe axis direction. For internal pressure, the circumferential stress is the largest, and the stress varies depending on the water pressure at the hydroelectric power plant. The circumferential stress generated iron pipes 1 sigma in the state of unreinforced, the pressure p, the inner diameter D, when the thickness of the steel pipe 1 and t _s,
σ = pD / 2t _s
Can be expressed as
[0015]
On the other hand, when a hydraulic iron pipe is used for a long time for hydroelectric power generation, corrosion progresses according to the number of years elapsed. As a typical damage mode of a hydraulic iron pipe, there is a reduction in the thickness of the pipe body due to corrosion and wear. The degree of corrosion varies depending on the equipment utilization rate, but also varies depending on the water system of the hydroelectric power plant.
[0016]
In this embodiment, the PAN-based carbon fiber reinforced resin (CFRP) is bonded to the surface of the iron pipe 1 to reinforce the iron pipe 1 in order to reduce the thickness of the pipe body plate in the hydraulic iron pipe. According to the above-mentioned document 1, the generated stress σ ′ of the reinforcing pipe is
σ '= λσ
_{λ = t s E s / (} t s E s + Nt T E T)
Can be expressed as Here, E _s is the elastic coefficient of the iron pipe 1, t _T is the thickness per sheet, E _T is the elastic coefficient of the sheet, and N is the total number of sheets reinforced.
[0017]
Here, in general reinforcement by CFRP including repair / reinforcement of reinforced concrete members, for example, after primer treatment such as cleaning of the member to be reinforced, a primer is applied to correct unevenness, which is correction of unevenness, and ink marking. Is applied, an adhesive is applied. Thereafter, a carbon fiber sheet is attached, and a CFRP process by resin impregnation and defoaming is performed. On the formed CFRP, the adhesive coating process, the sheet sticking process, and the CFRP process are repeated as many times as necessary, and finally a finishing process is performed, and a series of steps for reinforcement is completed.
[0018]
In such general reinforcement by CFRP, it takes time to impregnate the resin, and a curing period is required for each layer, so that the construction time at the site becomes longer. In particular, in the field of hydroelectric power generation, a scaffold for work is poor and it is difficult to perform work for a long time. Furthermore, since the work site is mountainous, it is not possible to secure a wide space necessary for attaching the carbon fiber sheet, and it is impossible to apply a conventional construction method. In the present embodiment, in order to cope with such problems, CFRP molded products are manufactured in advance in the factory with dimensions along the shape of the iron pipe 1 to reduce the work on site, thereby reducing the work period on site. To improve quality.
[0019]
FIGS. 2A and 2B are views showing a first example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied, and FIG. 2A is shipped from a factory. A molded product of the hydraulic iron pipe reinforcing member is shown, and FIG. 2 (b) shows a state where it is attached to the iron pipe 1. As shown in FIG. 2 (a), in the first example, a CFRP molded product (fiber reinforced resin portion) 11 having an opening (closing portion) 12 is provided, and has a thickness of 2 mm, for example. In consideration of production efficiency and the like, for example, it is also preferable that four sheets of about 0.5 mm thick sheets are stacked and FRP-made at a factory. The CFRP molded product 11 is molded in consideration of the outer shape (iron pipe diameter) of the iron pipe 1. For example, in the case of the iron pipe 1 having an inner diameter of 1.6 m, the inner diameter of the pipe of the CFRP molded product 11 is determined in consideration of the wall thickness (for example, 9 mm) of the iron pipe 1 in the inner diameter of 1.6 m. Furthermore, although the axial length of the molded product depends on the shape of the iron pipe 1 to be reinforced, the length of the molded product is excellent in that it does not hinder transportation and conveyance from the factory to the site if it is 10 m to 20 m.
[0020]
The opening (closing portion) 12 is provided for attaching the iron pipe 1 at the site. The CFRP molded article 11 is not closed as a pipe because it is necessary to attach and cover the iron pipe 1 at the site. Using the bending of the CFRP molded product 11, that is, the flexibility of the CFRP molded product 11, the opening (closing portion) 12 is expanded and an adhesive is applied as shown in FIG. It is attached to the iron pipe 1. The iron pipe 1 and the CFRP molded product 11 that is a molded product can be basically bonded with an adhesive or with a filler (resin) injected during closing.
[0021]
Further, as shown in FIG. 2A, fibers 13 composed of a plurality of layers protrude from the end of the CFRP molded product 11 in the opening (closing portion) 12. As will be described later, for example, when the opening (closing portion) 12 is closed after the CFRP molded product 11 is attached, the fibers 13 are overlapped using an adhesive for each layer, and the resin is impregnated in order from the lower layer. Is done. By bonding and impregnating all the fibers 13, the outer periphery of the iron pipe 1 can be covered with the FRP structure. As described above, according to the hydraulic steel pipe reinforcing member (fiber reinforced resin) shown in FIG. 2 (a), the processability when producing a molded product is high, and the process at the site can be greatly simplified. .
[0022]
The same applies to other examples which will be described later, but the same fiber (not shown) is provided at the axial end (not shown) of the CFRP molded product 11 and a hydraulic iron pipe reinforcing member is connected. It is also possible to configure so as to cope with the stress generated in the axial direction. Moreover, an epoxy resin, vinyl ester, etc. are used as an adhesive agent.
[0023]
FIG. 3 is a view showing a second example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied. Here, a plurality of CFRP molded products (for example, the first CFRP molded product 21 and the second CFRP molded product 22) created at the factory are superposed on the site, and each is bonded and reinforced. In FIG. It shows the state of being installed on site. That is, first, as in the first example shown in FIG. 2, after the adhesive is applied to the iron pipe 1, the lowermost molded product (first CFRP molded product 21 in FIG. 3) is fitted into the iron pipe 1, and the opening is opened. The part is impregnated with resin and closed. Then, after applying an adhesive to the outside of the closed molded product (first CFRP molded product 21 in FIG. 3), the next molded product (second CFRP molded product 22 in FIG. 3) is inserted from a direction shifted by, for example, 180 degrees. Then, the opening is impregnated with resin and closed.
[0024]
In FIG. 3, only two molded products (the first CFRP molded product 21 and the second CFRP molded product 22) are shown for explanation, but a plurality of molded products can be further stacked. For example, four layers of a 0.5 mm thick molded product are stacked to obtain a thickness of 0.5 × 4 = 2 mm as CFRP. In particular, in the case of a single molded product as shown in FIG. 2 (a), when the plate thickness is too thick to be expanded, a highly flexible and thin-walled hydraulic pressure as shown in FIG. If a plurality of steel pipe reinforcing members (fiber reinforced resins) are used, the installation work at the site becomes easy.
[0025]
FIGS. 4A and 4B are views showing a third example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied. This third example is characterized in that the hardened portion of the CFRP molded product is divided to provide a highly flexible deformable portion and the attachment performance to the iron pipe 1 is improved. In FIG. 4A, the fiber portion 33 which is an unimpregnated portion is provided between the plurality of hardened portions 31 included in the CFRP molded product, and the flexibility of the fiber portion 33 when the CFRP molded product is attached to the iron pipe 1. Is used to push the opening 32 open. 4B, a semi-cured portion 34 that is an uncured portion in a prepreg state that is not completely cured is provided in place of the fiber portion 33 shown in FIG. The opening 32 can be expanded using the flexibility of the. The configuration of the opening 32 may be the same as that of the opening 12 shown in FIG. 2A, but since the deformable portion is provided separately, the size (the length of the arc) is reduced. Is possible.
[0026]
In the example shown in FIG. 4A, after being attached to the iron pipe 1, the resin is soaked into the fiber portion 33 to form FRP. That is, since the fibers of each layer are continuous in the unimpregnated portion, all the layers are impregnated together at the site after being attached to the iron pipe 1. Moreover, in the example shown in FIG.4 (b), after attaching to the iron pipe 1, the semi-hardened part 34 is hardened by heating on the spot, for example. According to the example shown in FIGS. 4 (a) and 4 (b), it is excellent in applicability to an iron pipe 1 having a large diameter, is easy to maintain its shape, and at the same time can be easily attached on site. There is. 4B is particularly effective when there is a risk of cutting only with the fiber portion 33 in FIG. 4A.
[0027]
FIG. 5 is a view showing a fourth example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied. This fourth example is characterized by combining a plurality of molded products such as half cracks. That is, as shown in FIG. 5, a plurality of CFRP molded products 41 that are formed in accordance with the outer diameter of the iron pipe 1 and are designed to divide the outer periphery of the iron pipe 1 into equal parts are used. The plurality of CFRP molded products 41 are attached to the iron pipe 1 with an adhesive, for example. Thereafter, the portion of the fiber 42 provided at the end of the CFRP molded product 41 is bonded and impregnated, thereby reinforcing the iron pipe 1.
[0028]
In the fourth example shown in FIG. 5, the transportability from the factory where the CFRP molded product 41 is manufactured to the work site is greatly improved. In addition, there is no space for storage. Furthermore, it is possible to attach to the iron pipe 1 without depending on the flexible portion, and it is possible to improve the installation workability in the field.
[0030]
Next, the closing between the end portions in the molded product will be described . In the first example to the fourth example of the above mentioned, it leaves out previously fibers from the end portion of the molded article to closing, the site of the resin impregnated in to closure. The continuous process of the fiber at the time of closure, closing the process according to the machine械的joint closure method and the like are contemplated by overlap fibers.
[0032]
FIG. 6 (a), the (b) is a diagram showing an example of a closure process according to mechanical joint, similarly, openings in the circumferential direction of the molding shown in FIGS. 2 to 5 (12 etc.) It is shown in detail. A mechanical joint 83 such as a snap is provided at the tip of the fiber 82 protruding from each layer of the CFRP molded product 81, and the fiber 82 is connected by a mechanical joint 83 at each end of each layer. As shown in FIG. 6 (b), the resin 82 is put between the fibers 82 connected by the mechanical joint 83 and impregnated, thereby enabling the on-site closing. According to this mechanical joint 83, the strength of the joint can be kept high.
[0033]
FIG. 7 is a diagram showing an example of a closing method using overlapping fibers. Here, a CFRP molded product 91 made of six layers of CFRP, and fibers protrude from the end portion every other layer. The reason for setting every other layer is that, for example, in the case of a woven fabric, there is a thickness, and if all the layers are protruded, only the thickness increases. In the example shown in FIG. 7 , fibers are alternately laid in the lap section and impregnated every one to two layers. Finally, the overlap fiber 92 is bonded. By providing the overlap section by the overlap fiber 92, the strength of the joint can be increased.
[0034]
In addition, since the stress of the circumferential direction is dominant in the normal hydraulic iron pipe, in this Embodiment, it demonstrated centering on the reinforcement of the circumferential direction. Whether or not reinforcement is required in the axial direction depends on the type of iron pipe, and if it is not necessary, it is only necessary to place the CFRP molded product as it is. However, in order to reinforce axial stresses as well, corresponding axial reinforcement can be performed using FRP. This axial closing is not limited to the closing method as described with reference to FIGS . 6 and 7 , but may be closed by simply impregnating the fibers for overlap and forming FRP.
[0035]
As described above in detail, in the present embodiment, a FRP molded product that matches the diameter of the iron pipe 1 is created at the factory, and the FRP molded product is configured to be closed on the site after being attached to the iron pipe 1. did. This makes it possible to reinforce the hydraulic iron pipe in a state where the work on site is greatly reduced with respect to the hydraulic iron pipe provided at a steep slope between mountains.
[0036]
In the above description, an example of using a molded product of CFRP, which is FRP using carbon, has been described, but if necessary, glass (G), aramid, boron, carbon silicon, whisker ( It is also possible to reinforce with FRP made of fibers such as ceramic whiskers such as graphite, alumina, silicon carbide and silicon nitride, metal whiskers such as iron, nickel and chromium), and polyethylene. However, CFRP is lightweight and has a high elastic modulus, and is very suitable for the purpose of reinforcing a hydraulic iron pipe such as firstly ensuring rigidity and secondly ensuring strength. In addition, if necessary, the optimum FRP can be selected as appropriate, for example, by arranging GFRP for preventing electric corrosion in the lowermost layer (innermost layer) and GFRP for shock absorption in the uppermost layer (outermost layer). It is.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to greatly shorten the construction period in the field in the reinforcement work of the hydraulic pipe, which is generally difficult to work.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an iron pipe structure in which a method for reinforcing a hydraulic pipe in the present embodiment is executed.
FIGS. 2A and 2B are views showing a first example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied.
FIG. 3 is a view showing a second example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied.
4 (a) and 4 (b) are views showing a third example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied.
FIG. 5 is a view showing a fourth example of a hydraulic iron pipe reinforcing member (fiber reinforced resin) to which the present embodiment is applied.
FIGS. 6A and 6B are diagrams showing an example of a closing method using a mechanical joint.
FIG. 7 is a diagram showing an example of a closing method using overlapping fibers.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Iron pipe (hydraulic iron pipe), 2 ... Ring girder, 11 ... CFRP molded product (fiber reinforced resin part), 12 ... Opening part (closed part), 13 ... Fiber, 21 ... 1st CFRP molded product, 22 ... 2nd CFRP molded Product 31, cured portion 32, opening portion 33 fiber portion 34 semi-cured portion 41 CFRP molded product 42 fiber 8 1 CFRP molded product 82 fiber 83 mechanical joint 91 ... CFRP molded product, 92 ... overlapping fiber

Claims (8)

An attachment step of attaching a fiber reinforced resin (FRP) molded in advance according to the shape of the hydraulic pipe to be reinforced to the hydraulic pipe using an opening of the fiber reinforced resin;
An adhesive application / filler injection step of applying an adhesive or injecting a filler between the hydraulic pipe and the fiber reinforced resin before and after the attachment step;
Have a, a closure step of closing the opening after mounting the fiber-reinforced resin to the penstock,
The fiber reinforced resin, the fiber has been taken out in advance from the end of the fiber reinforced resin in the opening,
The said closing process closes using a mechanical coupling with respect to the said fiber, The hydraulic pipe reinforcement method characterized by the above-mentioned . The fiber reinforced resin partially includes a non-cured portion having flexibility,
The hydraulic pipe reinforcing method according to claim 1, wherein in the attaching step, the fiber reinforced resin is spread and attached to the hydraulic pipe using the non-cured portion.   The hydraulic pipe reinforcing method according to claim 1, wherein the closing step uses a reinforcing material that covers the opening, and causes the reinforcing material to overlap and adhere to the fiber reinforced resin.   2. The method of reinforcing a hydraulic pipe according to claim 1, further comprising a step of attaching another pre-molded fiber reinforced resin to the fiber reinforced resin after attaching the fiber reinforced resin and closing the opening. . A fiber reinforced resin portion pre-shaped in a shape along the outer periphery of the hydraulic pipe to be reinforced,
Provided at the end of the fiber reinforced resin portion, and a closed portion that is closed after attaching the fiber reinforced resin portion to the hydraulic pipe,
The closing portion projects fibers used for closing by a mechanical joint from the end portion of the fiber reinforced resin portion,
A hydraulic pipe reinforcing member that reinforces the hydraulic pipe against stress acting on the hydraulic pipe by the fiber reinforced resin portion and the closed closing portion. The hydraulic pipe reinforcing member according to claim 5, further comprising a non-cured part having flexibility required when the fiber reinforced resin part is attached to the hydraulic pipe. Pre-molded in a shape along the outer circumference of the hydraulic pipe to be reinforced,
When attached to the hydraulic pipe, it has a predetermined flexibility required to be spread out,
A fiber reinforced resin for reinforcing the hydraulic pipe that is closed after attaching the molded part to the hydraulic pipe and reinforces the hydraulic pipe against stress acting on the hydraulic pipe ,
A fiber reinforced resin characterized in that a fiber used for the closing by a mechanical joint protrudes from an end of the fiber reinforced resin . The fiber reinforced resin for reinforcing a water pipe according to claim 7 , wherein the fiber reinforced resin is a carbon fiber reinforced resin.

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