JP2008063744A - Method for reinforcing existing structure with carbon fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing method which facilitates diagnosis after the occurrence of moderate-sized earthquakes, which requires only minimum substrate treatment in construction, which enables a reinforcing resin to be easily and surely impregnated with a resin, and which facilitates construction. <P>SOLUTION: In this method, the existing structure is reinforced in such a manner that a braid-like or strip-shaped carbon fiber-containing reinforcing material is spirally or streakily wound at predetermined intervals around a surface of an existing structure. When a braid-like or strip-shaped carbon fiber material, which is not impregnated with the resin, is impregnated with the resin and turned into a reinforcing material, the braid-like or strip-shaped carbon fiber material, which is not impregnated with the resin, passes through the resin tank which is filled with the impregnation resin, immediately before being wound around the structure. Particularly, the resin tank is included in a handheld device 1; the carbon fiber material is impregnated with the resin through the resin tank in the device; and the carbon fiber material 3' after resin impregnation is wounded as-is around the existing structure after being pulled out from the device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for reinforcing structures such as columns, beams, and chimneys using carbon fibers, and more particularly to a reinforcing method for enhancing the shear resistance or dust performance of a concrete structure.

  Existing concrete structures such as concrete beams and columns, bridge piers, and chimneys are greatly different in strength depending on design standards at the time of construction as well as a decrease in proof stress due to deterioration over time. In the previous Great Hanshin-Awaji Earthquake, the new earthquake resistance standards were reviewed based on the experience that damage to buildings that met the standards of the new earthquake resistance design law enforced in 1981 was minor. Is also required to comply with the new seismic standards.

  In the case of an existing structure, if it is demolished and newly constructed, a structure satisfying the new earthquake resistance standard can be obtained. However, the construction has a long period of time and the cost thereof is great. Therefore, seismic reinforcement work is usually carried out unless it has deteriorated significantly.

  As such seismic reinforcement work, a method of winding a steel plate around a concrete structure such as a column is known. However, since the steel plate is heavy, construction requires time and large-scale equipment, and there is a problem in long-term durability such as generation of rust.

  On the other hand, from the viewpoint of being lightweight and having long-term durability, a reinforcing method using a reinforcing material using a reinforcing fiber sheet is known. For example, the figure shows a schematic diagram of the seismic reinforcement method for concrete columns. The flow sheet is shown in the figure.

  In order to make the seismic reinforcement effect of the carbon fiber sheet (CF sheet) sufficiently, smoothing is achieved by removing protrusions and steps on the concrete surface, and sanding is applied so that the corners are rounded. Then, the base processing (PS1) is performed. Subsequently, in order to improve the adhesion of the CF sheet to the ground-treated concrete surface and the impregnation property of the impregnating resin to the carbon fiber sheet, a primer is applied to the ground-treated concrete surface (PS2). At this time, if necessary, perform unevenness adjustment with putty, etc., but after applying the primer, the epoxy primer is dry to the touch when it is not touched by hand, and the acrylic primer is raised. However, it is necessary to be in a completely cured state that does not follow. Subsequently, the resin to be impregnated into the CF sheet is undercoated (PS3), the CF sheet is attached (PS4), and the impregnated resin is overcoated onto the CF sheet (PS5). Bubbles contained in the CF sheet are removed (PS6). When pasting CF sheets in multiple layers, undercoating, CF sheet pasting, topcoating, and defoaming are repeated. Thereafter, the resin is cured so that the impregnated resin is sufficiently cured.

  In general, the undercoating and overcoating of the impregnating resin are performed using a brush or a roller. In addition, the CF sheet is attached with care so as not to leave a large amount of bubbles and wrinkles that cause insufficient adhesive strength, and is sufficiently adhered to the concrete by pressing with a defoaming roller or a palm. In addition, when bubbles cannot be removed, a cut may be made in the fiber direction of the CF sheet to remove air. In such a case, the resin is applied again to the cut. Further, the top coating of the impregnating resin is similarly applied to the surface of the CF sheet when the undercoating impregnating resin slightly floats on the surface.

  However, the method of applying the impregnating resin using a brush or a roller (so-called hand lay-up method) has a problem that a difference in uniformity is likely to occur depending on the skill of the operator. In addition, the CF sheet should be attached with care so that no bubbles or wrinkles are generated, which also requires the skill of the operator.

  In addition, in the entire winding with a CF sheet, the adjustment process for steps, protrusions, unevenness, etc. is an indispensable process for obtaining sufficient adhesiveness, which complicates the process, increases costs, extends the construction period, etc. It is also a cause.

  For example, FIG. 8 shows a ground treatment in the case where there is a large step, and it is necessary to repair the upper portion of the step by mortar or the like so that the upper portion of the step is cut off and the lower portion is continuous with the cut surface. In addition, even for small steps due to differences in formwork, etc., after the scraping treatment, the carbon fiber sheet is arranged so that it adheres to the column surface by smoothing treatment using an epoxy-based putty etc. after the primer coating surface is cured by touch. It is said that it must be.

  In addition, unlike the reinforcement with a CF sheet, a method using a fiber reinforced resin composite material (FRP) molded in a predetermined shape in advance is known. Since FRP is impregnated with resin in the manufacturing process, undercoating and overcoating of the impregnating resin at the work site is not necessary, but primer treatment is indispensable for bonding, and if there are protrusions, a CF sheet is attached. The ground treatment is required in the same manner as the attachment. Further, when there is a step, it is necessary to perform flattening that is larger than the CF sheet pasting or to prepare a molded product that matches the step shape. Therefore, the use of a molded product is poor in versatility as a method for reinforcing columns and the like.

  In addition, when constructed in this way, the concrete surface will be covered with a reinforcing fiberboard after construction. For example, if a medium-scale earthquake occurs, whether or not the concrete is cracked. Diagnosis is very difficult.

  On the other hand, unlike the above-described full surface reinforcement, a method of partially reinforcing is known. For example, in Patent Document 1 (Japanese Patent Laid-Open No. Sho 62-244777) and Patent Document 2 (Japanese Patent Laid-Open No. Sho 62-242058), high-strength long fiber strands are spiral-shaped as a method for seismic reinforcement of existing concrete columns. The method of winding is shown. In these, there is a description that when a fiber filament is impregnated with a resin to form a strand, the resin is impregnated in advance or impregnated after winding, but there is no detailed description.

  Similarly, in Patent Document 3 (Japanese Patent Laid-Open No. 2002-115403), in order to reinforce a concrete column with a wall, a plurality of through holes are formed in the wall at intervals in the longitudinal direction of the column. It has been proposed to wind a bundle of reinforcing fiber strands around the periphery of the column through a hole. There are two possible timings for impregnating the resin, depending on the curing time of the resin. When an impregnated adhesive resin having a relatively short curing time is used, the resin is simultaneously used when winding a bundle of reinforcing fiber strands. When an impregnated adhesive resin having a relatively long curing time is used, the bundle of reinforcing fiber strands is impregnated with the resin in advance, and is wound and stuck on site.

  In the construction method using strands, the strands must be wound several times to obtain the required amount of reinforcement, so there is almost no manual wrapping and a dedicated wrapping machine is used. There is a problem that it is scarce. When reinforcing with a reinforcing fiber such as carbon fiber, the above-mentioned sheet construction method is simple in order to obtain a necessary amount of reinforcement, and is widely used because it can be constructed manually.

  As described above, the method of applying the impregnating resin by the hand lay-up method has a problem that a difference in uniformity is likely to occur depending on the skill of the operator. In order to solve this problem, in Patent Document 4, a continuous fiber sheet impregnated with a resin is formed in parallel with a clearance and a compression force adjusted so that the weight ratio of resin / fiber is 55/45 to 35/65. A method of reinforcing a structure is shown in which a resin-impregnated continuous sheet in an uncured state with the above-mentioned weight ratio is passed between two rolls, and this is wound or attached in a single layer or multiple layers on the outer surface of the structure. . Here, the impregnated sheet is rewound into a roll and used after being pulled out on site. Therefore, it is necessary to take up carefully so as not to cause wrinkles or the like during rewinding.

In Patent Document 5 (Japanese Patent Laid-Open No. Hei 6-288101), instead of the conventional sheet pasting method, a thermoplastic fiber is mixed into a reinforcing fiber wound around a concrete structure and knitted into a long cloth shape. In addition, there is shown a construction method and an apparatus therefor, in which both sides of this long cloth-like reinforcing fiber are heated and wound around a concrete structure while dissolving the mixed resin. This apparatus is provided with a pair of rollers that rotate in contact with both the front and back surfaces of a long cloth, and a heating device is provided inside each roller. By using such an apparatus, it is said that the working time can be reduced as compared with the conventional sheet pasting method. However, this method is also premised on winding around the entire surface of the object to be reinforced, and the ground treatment needs to be performed in the same manner as in the past. Also, in this method, a thermoplastic resin is used, and a thermosetting resin such as an epoxy resin having excellent adhesive strength, or a room temperature curable resin such as an epoxy adhesive cannot be used, so that the adhesive strength is inferior. There's a problem. In addition, since the construction is performed while the thermoplastic resin is melted, the construction speed is not always sufficiently high. In addition, during construction, the resin will not be completely melted or unevenly melted when it is installed before the heating roller reaches the prescribed temperature, or at a speed higher than the prescribed speed, or during construction in winter. These may cause voids and poor adhesion.
JP-A-62-244977 JP-A-62-242058 JP 2002-115403 A Japanese Patent Laid-Open No. 2000-896 JP-A-6-288101

  The purpose of the present invention is that diagnosis after the occurrence of a medium-scale earthquake is easy, and at the time of construction, the minimum surface treatment is sufficient, and the resin impregnation into the reinforcing fibers can be carried out easily and reliably. An easy reinforcement method will be provided.

  The present inventors are developing a reinforcement method for winding a braided carbon fiber material or a band-like carbon fiber material in a striped or spiral manner with a predetermined interval as a new construction method that replaces the continuous fiber reinforcement construction method. The braided carbon fiber material or band-like carbon fiber material used in the present invention has a relatively large amount of carbon fiber, and the brush coating or roller coating performed by the conventional continuous fiber construction method cannot sufficiently impregnate the resin to the center. There is. Therefore, in the present invention, a method is adopted in which the resin is impregnated by passing through a resin tank immediately before winding and wound as it is.

  That is, the present invention is a method of reinforcing a braided or band-like carbon fiber-containing reinforcing material on a surface of an existing structure by winding it at a predetermined interval in a spiral or striped manner, which is a resin-unimpregnated braided or band-like carbon fiber When the material is impregnated with a resin and used as a reinforcing material, the non-resin-impregnated braided or band-like carbon fiber material is passed through a resin tank filled with the impregnated resin immediately before being wound around the structure It relates to said method.

  In particular, in the present invention, the resin tank is included in a hand-held apparatus, and the carbon fiber material is impregnated with resin through the resin tank in the apparatus, and the carbon fiber material after resin impregnation is pulled out from the apparatus. It is preferable that the surface of the existing structure is plated as it is.

  In the present invention, since the carbon fiber material (hereinafter referred to as CF material) is impregnated with resin immediately before winding, it can be sufficiently impregnated with braided or strip-like CF material having a relatively large amount of carbon fiber, and at the same time can be held by hand. Construction is easy with simple equipment.

  In addition, by performing winding at a predetermined interval, it is easy to diagnose after the occurrence of a medium-scale earthquake, and there is an effect that minimal ground processing is sufficient for construction.

  In the present invention, the CF material is impregnated with resin by passing it through a resin tank in which the impregnated resin is stored immediately before being wound around the structure to be reinforced. In particular, in the present invention, it is preferable to use an apparatus that can be held by an operator for resin impregnation.

  FIG. 1 is a three-side view (a front view (a), a top view (b), a side view (c)) showing an example of a resin impregnation apparatus 1 that can be used in the present invention, and FIG. 2 illustrates the inside of the apparatus. FIG. This apparatus 1 has means 4 for holding the CF material 3 supplied in roll form, a resin tank 8 in which the impregnating resin 7 is stored, the CF material 3 is guided to the resin tank 8, and passes through the resin tank 8. There are provided various rollers for guiding the CF material 3 ′ to the CF material discharge port 5, and a handle 2 that can be held by hand. A part of the exterior (opening / closing part 6) is provided so as to be openable and closable, and is configured to be opened so that the CF material can be installed in the apparatus. Also, maintenance of the internal device can be performed by opening a part of the exterior.

  A part of each roller included in the internal device is movable as shown in FIG. 2 to facilitate installation of the CF material in the device. In FIG. 2, (a) shows the roller arrangement at the time of CF material installation, and (b) shows the roller arrangement at the time of resin impregnation.

  When installing CF material in the apparatus, the tip part may be installed through the resin tank, but a dummy tape or the like is provided at the tip part of the CF material and installed inside the apparatus without passing through the resin tank. A method of passing the CF material through the resin tank is preferable because it is simple and can be used without waste.

  The rollers 10 and 10 ′ are immersion rollers for immersing the CF material in the resin tank 8. The rollers 10 and 10 ′ are positioned on the resin tank 8 when the CF material 3 is installed in the apparatus, and descend into the resin tank 8 when immersed. It has a mechanism to do. Although two immersion rollers are provided in this example, one immersion roller or three or more immersion rollers may be provided. The squeezing rollers 11 and 11 ′ are opposed to each other with the CF material 3 ′ after passing through the resin tank 8, and are separated when the CF material is installed, but are sandwiched between both rollers when immersing so that excess resin is squeezed out. Can do. Thereafter, the CF member 3 ′ impregnated with the resin is pulled out from the discharge portion 4 through the direction regulating rollers 12 and 12 ′ and the discharge port rollers 13 and 13 ′.

  In this device, the CF material drawn out from the roll (especially the strip-shaped CF material) is transported in the horizontal direction in the device, but when reinforcing the RC pillar or the like, it is attached to a vertical surface. At that stage, it is necessary to add a twist to the CF material. In the apparatus shown in FIGS. 1 and 2, the CF material discharge section 4 is configured to be rotatable so that a twist is applied in the apparatus. In this way, by applying a twist in the apparatus and controlling the CF member 3 ′ in the direction optimal for the attaching location, the attaching operation becomes easy.

  When the CF material 3 is passed through the resin tank 8, it is preferable to provide means for regulating the conveyance speed so that the conveyance speed of the CF material does not exceed a predetermined value in order to keep the impregnation state of the resin 7 constant. It is preferable that such a conveyance speed regulation means can regulate at least the rotation speed of the squeeze rollers 11 and 11 '. The conveyance speed of the CF material is not limited in general depending on the basis weight of the CF material and the viscosity of the impregnating resin, but may be a speed of about 1 m / min to 10 m / min.

  Further, in order to improve the resin impregnation property, as shown in FIG. 3, a roller (14, 14 ′) for applying pressure to the CF material is provided in the resin tank against the immersion roller, and the air in the CF material is When extruded, the inside of the CF material becomes a negative pressure and the impregnation property of the resin increases.

  The impregnating resin in the apparatus may gel with time and the resin impregnation property may deteriorate, but in the present invention, since the amount that can be filled in the apparatus that can be held is not so much, even if it gels, it is too wasteful. In addition, since work can be performed quickly by improving workability, it is possible to work within the pot life of the resin.

  It is preferable that the inside of the apparatus is made of lining with a releasable material so that the gelled resin can be easily removed, and the roller or the like is made of silicone rubber having excellent releasability.

<CF material>
The band-like and braid-like CF materials each preferably have a member width of 10 mm or more and 50 mm or less. The weight is preferably in the range of 10 g / m to 100 g / m. In particular, the present invention is effective when the basis weight of the carbon fiber is large. For example, while the basis weight of a conventional carbon fiber sheet used for full-scale reinforcement is about 300 g / m ² from the construction method, the strip-like CF material used in the present invention is a conventional carbon fiber sheet. Even if the amount of carbon fiber is as large as twice or more (600 g / m ² or more), the resin can be sufficiently impregnated into the fiber.

1. Band-like CF material As shown in FIG. 4, the band-like CF material 30 is a cloth-like material in which a bundle of carbon fibers is oriented in one direction as warps 31 and bundled with wefts 32 such as polyethylene in order to suppress variation.

2. Braided CF material The “braid” is basically composed only of warp, and is different from “woven fabric” composed of warp and weft and “knitted fabric” composed of continuous loops. Braids used in the present invention (also called “strings”) are mechanically manufactured, and can be broadly divided into 8 strokes (Yatsuuchi), 16 strokes (Dukurokuuchi), hammering (Kongouuchi), and many others. being classified. Also, there are flat punching assembled into a flat shape and round punching assembled into a round shape. FIG. 5 shows a schematic diagram of braided CF material that has been punched in eight strokes.

3. Reinforcing fiber Reinforcing fiber to be used uses carbon fiber, but glass fiber, aramid fiber, other organic fibers, etc. can be mixed and used without any problem, and can be appropriately selected according to the application. it can. As the carbon fiber to be used, for example, in the tensile test method of carbon fiber reinforced plastic according to JIS K7073, the high strength type is 2.45 × 10 ⁵ N / mm ² , and the middle elastic type is 4.40 × 10. ⁵ N / mm ^2, the high modulus type using a material having a tensile modulus of ^{6.40 × 10 5 N / mm 2} .

<Impregnating resin>
As the resin to be impregnated, a room temperature curable epoxy resin, a thermosetting epoxy resin, a thermosetting resin such as a polyester resin, a radical reaction resin such as methyl methacrylate, or the like can be used. In particular, it is preferable to use a room temperature curing type epoxy resin. For example, trade names “Bond E2500” series and “CFB500” series manufactured by Konishi Co., Ltd. can be used.

<Construction method>
First, the ground treatment of the construction part is performed. This surface treatment removes the decorative coating on the concrete surface, and performs simple shaping of the concrete surface, rounding of the corners, repair of cracks, etc., and does not require a large step treatment.

  Thus, in order to improve the adhesiveness between the reinforcing member and the concrete, the reinforcing portion can be subjected to a primer treatment. As the primer, similarly to the resin impregnated into the reinforcing member, a thermosetting adhesive such as a room temperature curing type or a thermosetting type epoxy resin or a polyester resin can be preferably used. For example, a primer such as “Bond E800” series manufactured by Konishi Co., Ltd. is preferable.

  Next, the CF material passed just before the resin tank is wound around the concrete surface subjected to the primer treatment is wound at a predetermined interval. FIG. 6 is a schematic view showing the state of construction on the RC pillar 51 using the apparatus of the present invention. The operator holds the apparatus 1 in his hand and pulls out the CF material 3 ′ that has passed through the resin tank. It can be easily constructed by turning around the RC pillar 1. When the predetermined winding is performed, the CF material 3 ′ is cut, and then the next construction site is constructed.

  After winding the CF material, the carbon fiber resin reinforced material (CFRP) 52 is obtained by curing until the impregnating resin is sufficiently cured. Thereafter, in order to maintain the aesthetics of the surface or further improve the durability of the reinforcing member, finishing can be performed by applying a finishing mortar or spraying a coating or the like on the surface around which the reinforcing member is wound.

  The CF material is wound at a predetermined interval. The winding interval varies depending on the required reinforcement effect and cannot be limited to a specific range. For example, to reinforce the toughness of a reinforced concrete column, it is less than 2D (D indicates the height of the column cross section) from the upper and lower ends of the column. It is preferable to wind and reinforce the CF material around the toughness reinforcing section with a predetermined interval so that the winding interval (P) from the end of the column is 5 cm or more and P / D is 1/3 or less. Further, since a larger amount of reinforcement is required for toughness reinforcement, it is preferable to wrap the CF member in layers.

  On the other hand, since the shear reinforcement does not require the reinforcement amount as much as the toughness reinforcement, it can be wound at wider intervals. Shear reinforcement covers the entire section of the column, but usually it is often performed in combination with toughness reinforcement, and in that case, it may be applied to portions other than the toughness reinforcement section. In addition, since the CF material used in the present invention has a large amount of carbon fiber, a sufficient amount of shear reinforcement can be obtained by single winding.

  The present invention is particularly effective in toughness reinforcement with a large amount of reinforcement.

  In addition, the amount of reinforcement of toughness reinforcement and shear reinforcement is in accordance with, for example, “Guidelines for Design and Construction of Seismic Reinforcement Methods for Railway Viaduct Columns Using Carbon Fiber Sheets” issued by the Railway Technical Research Institute, It can be selected so that it is designed on the safe side.

It is a 3rd page figure (a front view (a), a top view (b), a side view (c)) which shows an example of the resin impregnation apparatus used by this invention. 2A and 2B are schematic diagrams for explaining the inside of the apparatus, in which FIG. 1A shows a roller arrangement when a CF material is installed, and FIG. 1B shows a roller arrangement when a resin is impregnated. It is the schematic explaining another embodiment of the resin impregnation method in a resin tank. It is a schematic perspective view of the strip | belt-shaped carbon fiber material used by this invention. It is a schematic perspective view of the braided carbon fiber material used by this invention. It is a figure explaining the construction method using the apparatus shown in FIG. It is the schematic which shows the reinforcement method by the conventional carbon fiber sheet. It is the flow sheet of the reinforcement method by the conventional carbon fiber sheet. It is a figure explaining the foundation | substrate process (step difference process) in a conventional process.

Explanation of symbols

1 Resin impregnation device 2 Handle 3 CF material 3 'CF material (resin impregnated)
4 Roll holding means 5 CF material discharge port 6 Opening / closing part 7 Impregnation resin 8 Resin tank 9 Roller 10, 10 'Impregnation roller 11, 11' Direction roller 12, 12 'Direction regulating roller 13, 13' Discharge roller 14, 14 ' Pressure roller 30 Strip CF material 31 Warp (carbon fiber)
32 Weft 40 Braided CF material 51 RC pillar 52 CFRP

Claims (3)

  A method of reinforcing a braided or band-like carbon fiber-containing reinforcing material on a surface of an existing structure by winding it in a spiral or striped manner at a predetermined interval, and impregnating the resin into a braided or band-like carbon fiber material that is not impregnated with resin When the reinforcing material is used as the reinforcing material, the braided or band-like carbon fiber material not impregnated with the resin is passed through a resin tank filled with the impregnating resin immediately before being wound around the structure.   The resin tank is contained in a hand-held apparatus, and the carbon fiber material is impregnated with resin through the resin tank in the apparatus, and the carbon fiber material after resin impregnation is pulled out of the apparatus and then the existing structure. The reinforcing method according to claim 1, wherein the surface is plated.   The reinforcing method according to claim 1 or 2, wherein the braided or strip-like carbon fiber not impregnated with resin has a member width of 10 mm to 50 mm and a weight of 10 g / m to 100 g / m.

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