JP2851680B2 - How to reinforce structures - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to reinforcement of structures such as bridges and elevated roads with fiber reinforced plastic, which can be reinforced with good workability at a reinforcement site and can be reinforced. The present invention relates to a method for reinforcing a structure that can also improve strength.

2. Description of the Related Art Bridge piers such as bridges and elevated roads are reinforced with fiber reinforced plastic.

Conventionally, there are two ways to reinforce it: (1) a method in which hardened fiber-reinforced plastic is applied to the reinforced portion of the pier; (2) a prepreg is applied to the reinforced portion of the pier to prevent deformation during heat curing. (3) wrap a reinforcing fiber cloth around the reinforced portion of the pier and impregnate it with a room-temperature-curable matrix resin, and press the holding tape. By leaving it after winding and curing
It is known to use fiber reinforced plastic.

Problems to be Solved by the Invention However, the method (1) described above has good reinforcement efficiency, but has a serious drawback that it cannot be performed at a curved reinforcement portion.

In the method (2), the prepreg adhered to the reinforcing portion of the pier must be heat-cured on site, and thus has a disadvantage that the heat-curing operation is not easy.

In the method (3), since the reinforcing fiber is used as a cross by plain weaving or twill weaving, the reinforcing fiber has a low strength at the intersection of the warp and the weft, and this is sufficient when the fiber is made into fiber reinforced plastic. There is a disadvantage that a great reinforcing effect cannot be obtained.

In addition to the above, a method of winding a fiber of a reinforcing fiber impregnated with a resin by a filament winding method on the reinforced portion of the pier on site and then curing it to form a fiber reinforced plastic is also considered, but the reinforcement target is limited. Has the disadvantage that the equipment cost is high.

Therefore, an object of the present invention is to improve the construction workability at the reinforcement site when reinforcing structures such as bridges and elevated roads with fiber-reinforced plastic in view of the above-mentioned situation, and to improve the reinforcement strength. The present invention provides a method for reinforcing a structure that enables the building to be performed.

Means for Solving the Problems The above object is achieved by a method for reinforcing a building according to the present invention.

In summary, the present invention provides a first unidirectionally arranged reinforcing fiber sheet in which first reinforcing fibers having high rigidity are arranged in one direction via an adhesive layer on a resin-permeable support sheet, A second unidirectionally-arranged reinforcing fiber sheet in which second toughening high reinforcing fibers are arranged in one direction via an adhesive layer on a resin-permeable support sheet; A method for reinforcing a building, characterized in that the first and second reinforcing fibers are bonded to a surface of a reinforcing portion after being impregnated with a room-temperature-curable matrix resin, and then the matrix resin is cured.

When the support sheet is resin-permeable, the first and second reinforcing fiber sheets are applied after applying a room-temperature-curable matrix resin on the surface of the reinforcing portion of the building, and then the first and second reinforcing fiber sheets are attached. Alternatively, the matrix resin may be impregnated into the second reinforcing fiber, or the first and second reinforcing fiber sheets may be impregnated with a room-temperature-curable matrix resin after the first and second reinforcing fiber sheets are pasted on the surface of the reinforcing portion of the structure. The second reinforcing fiber can be impregnated.

Preferably, the elastic modulus of the first reinforcing fiber is 5 tons / m.
m ² or more, and the elongation at break of the second reinforcing fiber is 1.2%
In addition, the elongation at break is 20% or more than the breaking elongation of the first reinforcing fiber.

Examples Hereinafter, examples of the present invention will be described.

1 (a) and 1 (b) are cross-sectional views showing an example of first and second unidirectionally reinforced fiber sheets used in the method of reinforcing a structure according to the present invention.

The above-mentioned first unidirectionally reinforced fiber sheet 1 is obtained by forming first reinforced fibers 4 having high rigidity on a support sheet 2 with an adhesive layer 3.
The second unidirectionally reinforced fiber sheet 5 is formed by bonding the second reinforcing fibers 6 having high toughness on the support sheet 2 via the adhesive layer 3. It is arranged and glued in the direction. The first and second reinforcing fiber sheets 1 and 5 are used for reinforcement by impregnating the reinforcing fibers 4 and 6 with a matrix resin at a reinforcing site such as a bridge or an elevated road.

In the present invention, these first and second reinforcing fiber sheets 1,
5 is used at least one by one with respect to the surface of the reinforcing portion of the building, and the matrix resin is cured on the surface of the reinforcing portion to form a hybridized fiber reinforced plastic, and the reinforcement is performed. Room temperature curing type resin is used for the matrix resin.
By leaving the reinforcing fiber sheets 1 and 5 of the above structure attached to the surface of the reinforcing portion of the building and leaving them, the matrix resin impregnated in the reinforcing fibers 4 and 6 can be cured to form a fiber-reinforced plastic.

In the present invention, with respect to the surface of the reinforcement point of the building,
First reinforcing fiber sheet 1 provided with reinforcing fibers 4 having high rigidity
Hybridizing fiber-reinforced plastics using two types of reinforcing fiber sheets, that is, reinforcing fiber sheets 5 provided with reinforcing fibers 6 having high toughness, is because the first reinforcing fibers 4 having high rigidity are used to destroy a structure. The second reinforcing fiber 6 having high toughness while increasing the strength so as not to easily crack.
The purpose of this is to increase the fracture toughness of the structure, prevent the structure from being immediately destroyed even if a crack is generated, and extend the time until the fracture.

FIG. 2 is a view perpendicular to the plane of the fiber-reinforced plastic when hybridized by using one reinforcing fiber sheet provided with high rigidity reinforcing fibers and one reinforcing fiber sheet provided with high toughness reinforcing fibers. 4 is a graph schematically showing a stress-elongation strain curve of a fiber-reinforced plastic when a load is applied.

FIG. 3 shows a case where two reinforcing fiber sheets provided with reinforcing fibers having higher rigidity but lower toughness than the above are used.
It is a graph similar to FIG.

In the case of the hybridized fiber reinforced plastic, as shown in FIG. 2, the stress σ is not as great as that of the non-hybridized fiber reinforced plastic, but the elongation strain ε is large, and the stiffened reinforcing fiber is initially fractured. In addition, since the high-toughness reinforcing fibers are prevented from breaking immediately after being greatly expanded, the final breaking at which the high-toughness reinforcing fibers are broken, the breaking energy indicated by the area surrounded by the curve in the figure is large. That is, it takes a long time until the entire fiber-reinforced plastic is broken.

On the other hand, in the case of non-hybridized fiber reinforced plastic, as shown in FIG.
Is high, but the true strain ε is small, and when the rupture of the reinforcing fiber starts, it immediately reaches the final rupture without elongation. Therefore, the fracture energy indicated by the area surrounded by the curve in the figure is small. That is, the time until the entire fiber-reinforced plastic is broken is short.

As described above, the two types of reinforcing fiber sheets, that is, the first reinforcing fiber sheet 1 provided with the high-rigidity reinforcing fibers 4 and the high-toughness reinforcing fiber 6 are used to form the fiber-reinforced plastic. By hybridizing
Increase the fracture toughness of the structure to prevent it from cracking easily, while increasing the fracture toughness of the structure to prevent the structure from cracking immediately and increase the time to failure Can be. Therefore, safety at the time of reinforcing the structure with the fiber reinforced plastic can be achieved.

Practically, the first reinforcing fiber 4 has an elastic modulus of 5 tons / m.
The second reinforcing fiber 6 preferably has a stiffness of not less than m ² , and the second reinforcing fiber 6 has a toughness such that the breaking elongation is 1.2% or more and the breaking elongation of the first reinforcing fiber 4 is 20% or more. preferable. If the elastic modulus of the first reinforcing fibers 4 is less than 5 ton / mm ² , the rigidity is too low, and the improvement in the breaking strength of the structure is not sufficient. If the elongation at break of the second reinforcing fiber 6 is less than 1.2% and not more than 20% greater than the elongation at break of the first reinforcing fiber 4, the improvement in the fracture toughness of the structure is not sufficient.

For the purpose of the present invention, it is necessary to use the first and second reinforcing fiber sheets 1 and 5 at least one at a time for the reinforcing points of the building, but the reinforcing fibers are appropriately reinforced in accordance with the degree of reinforcing to be performed on the reinforcing points. It goes without saying that a plurality of one or both of the fiber sheets 1 and 5 may be used. Also, the stacking order
The reinforcing fiber sheets 1 and 5 may be alternated, or the reinforcing fiber sheets 1 and 5 may be alternate, or the reinforcing fiber sheet 1 may be first and the reinforcing fiber sheet 5 may be later or vice versa.

If the reinforcing fibers 4 and 6 are a combination satisfying the above characteristic values, various reinforcing fibers such as pitch-based carbon fiber, boron fiber, PAN-based carbon fiber, aramid fiber, glass fiber, steel fiber, polyester fiber, polyethylene fiber, etc. Can be used.

As the support sheet 2, scrim cloth, glass cloth, release paper, nylon film, or the like is used.
Usually, the support body 2 does not need to have resin permeability, but if it is desired to be able to impregnate the reinforcing fibers 4 and 6 with the matrix resin after attaching the reinforcing fiber sheet 1 to the reinforcing portion of the structure. For the sheet 2, the above-mentioned scrim cloth, glass cloth and the like are used. Support sheet 2
Has a thickness of about 1 to 500 μm, and preferably about 5 to 100 μm, from the viewpoint of having flexibility and having a strength capable of supporting the reinforcing fibers 4 and 6.

As an adhesive for forming the adhesive layer 3, any material can be used as long as it can at least temporarily bond the reinforcing fibers 4 and 6 on the support sheet 2, but the reinforcing effect of the reinforcing fibers 4 and 6 by the matrix resin can be used. It is preferable that the same effect as described above is also given to the adhesive layer 3. From this viewpoint, it is preferable to use a resin having good compatibility with the matrix resin. For example, when an epoxy resin is used as the matrix resin, an epoxy-based adhesive is preferably used.

The thickness of the adhesive layer 3 is 5 to 100 μm, since it is sufficient that the reinforcing fibers 4 and 6 can be temporarily bonded.
m, preferably about 10 to 30 μm.

The reinforcing fibers 4 and 6 are scattered as a filament by arranging a large number of bundles of fibers or bundles of fibers that are lightly twisted and bundled with a sizing agent on the adhesive layer 3 and crushed from above. Thereby, the reinforcing fibers 4 and 6 are laminated on a plurality of layers by a binding agent or a twist, and the adhesive layer 3 is formed on one surface of the support sheet 2.
Are arranged in one direction and adhered.

In this case, as shown in FIG. 4 (a), a plurality of layers of the reinforcing fibers 4 form a bundle of these fiber bundles 4A on one surface of the support sheet 2 via the adhesive layer 3 in one direction. Side by side, fiber bundle
The lower part of the fiber bundle 4A is adhered to the adhesive layer 3 by crushing 4A from above, and as shown in FIG. 4 (b), the fiber bundle 4A is densely placed on the support sheet 2 without any horizontal space. May be provided,
Alternatively, as shown in FIG. 5 (a), the fiber bundles 4A are arranged in one direction on the support sheet 2 via the adhesive layer 3 at intervals in the horizontal direction, and the fiber bundles 4A are similarly placed from above. The lower portion of the fiber bundle 4A may be adhered to the adhesive layer 3 by crushing, and may be sparsely provided on the support sheet 2 at a lateral interval as shown in FIG. 5 (b).

The fiber bundle 4A can be used either with or without fiber opening between the fibers 4, that is, between filaments. The degree of crushing of the fiber bundle 4A depends on the layer thickness desired for the plurality of layers of the fibers 4 arranged in this manner.
As an example, when a carbon fiber bundle in which about 12,000 μm carbon fiber filaments are converged is crushed so that the width in the lateral direction becomes about 5 mm.

The above is the same for the reinforcing fibers 6 as for the reinforcing fibers 4.

The unidirectionally-arranged hybrid reinforced fiber sheet 1 of the present invention as described above can be manufactured, for example, as shown in FIG. 6 (the same applies to the unidirectionally-arranged hybrid reinforced fiber sheet 5).

That is, after the adhesive layer 3 is provided by applying an adhesive on the support sheet 2 supplied from the sheet supply roll 7 with the adhesive application roll 8, the sheet 2 is sent to the pressing unit 9, and the pressure is simultaneously applied. The fiber bundles 4A of the first reinforcing fibers 4 are fed from the reinforcing fiber supply roll 10 to the section 9, and the fiber bundles 4A are arranged in one direction on the adhesive layer 3 on the sheet 2. Further, the release paper 12 is fed from the release paper roll 11 to the pressurizing section 9 and is released onto the fiber bundle 4A.
Stack 12

Then, in this state, the fiber bundle 4A is crushed by applying pressure with the pressure rollers 13a and 13b of the pressure unit 9, and at the same time, the reinforcing fibers 4 which have been loosened slightly are bonded to the sheet 2 via the adhesive layer 3. Glue on one side of Thereafter, the release paper 12 is wound up by the release paper take-up roll 14 to thereby form the support sheet 2.
A unidirectionally-arranged reinforced fiber sheet 1 obtained by arranging and adhering reinforcing fibers 4 in one direction via the adhesive layer 3 on the adhesive layer 3 is obtained.

The reinforcing fiber sheet 1 is wound on a sheet winding roll 17 after the cover film 16 supplied from the film supply roll 15 is covered with the reinforcing fiber 4 as necessary.

The unidirectionally reinforced fiber sheet 5 can also be manufactured in the same manner as described above by using the fiber bundle of the reinforcing fibers 6 instead of the fiber bundle 4A.

In the present invention, as described above, the reinforcing fiber sheets 1, 5
Using reinforcement fiber at reinforcement sites such as bridges and elevated roads 4,
6 is impregnated with a room-temperature-curable matrix resin to provide reinforcement. As the room-temperature-curable matrix resin, an epoxy resin or the like that is cured at room temperature by adjusting the blending of a curing agent is used. . According to this, by leaving the fiber reinforced sheet 1 attached to the reinforcing portion and leaving it, the matrix resin can be cured to be made into a fiber reinforced plastic. This does not prevent promotion of curing.

According to the invention, the reinforcement of the structure is performed as follows.

That is, in one embodiment of the present invention, the reinforcing fibers on the unidirectionally-arranged hybrid reinforcing fiber sheets 1 and 5 are applied at a reinforcement site of a structure such as a bridge or an elevated road pier by appropriate application means such as a roller, a brush, or a spray. A room-temperature-curable matrix resin is applied to and impregnated to 4, 6 and, as shown in FIG. 7, the reinforcing fibers 4 and 6 are used as the reinforcing portion 18 side of the building, and the fiber-reinforced sheets 1 and 5 are formed as desired. The desired number of reinforcement points 18 in order
Paste around and laminate. Next, after performing an operation of impregnating the matrix resin with a hand roller or the like, covering is performed by wrapping a pressing tape thereon, etc., and thereafter, the matrix resin is cured by leaving it as it is. And do it. This reinforces the structure with the hybridized fiber reinforced plastic.

In another embodiment of the present invention, as shown in FIG.
A desired number of unidirectionally reinforced fiber sheets 1 and 5 are laminated with the reinforcing fibers 4 and 6 facing the reinforcing portion 18 side, and the sheets 1 and 5 are attached by pressing the coated fibers to a thickness of about 100 μm. At the same time, the reinforcing fibers 4 and 6 are impregnated with the matrix resin 19. In this case, when the support sheet 2 is not resin-permeable, every time the next sheet 1 or 5 is laminated on the previously laminated sheet 1 or 5, a matrix resin is further applied to the previous sheet 1 or 5. You may. Thereafter, in the same manner as described above, a cover is formed by winding a pressing tape on the laminated sheets 1 and 5, and thereafter, the matrix resin is cured by leaving it as it is, and the sheets 1 and 5 are converted to fiber reinforced plastic. I should do it. This results in the reinforcement of the structure with similarly hybridized fiber-reinforced plastics.

In still another embodiment of the present invention, as the unidirectionally-arranged hybrid reinforcing fiber sheets 1 and 5, the support sheet 2 is a resin-permeable sheet. As shown in FIG. 9, first, a resin of the same type as the matrix resin is applied as a primer 20 on the peripheral surface of the reinforcing portion 18, and sheets 1 and 5 are adhered thereon in a desired order and laminated. Thereafter, a room-temperature-curable matrix resin 19 is applied from above the outermost sheet 1 or 5 by a roller or the like, and penetrates through the sheet 2 to impregnate the matrix resin 19 into the reinforcing fibers 4 and 6.
Thereafter, in the same manner as described above, cover is performed by winding a pressing tape on the laminated sheet 1 or 5, and thereafter, the matrix resin 19 is cured by leaving it as it is, and the sheets 1 and 5 are made of a fiber-reinforced plastic. Just do it. This results in the reinforcement of the structure with similarly hybridized fiber-reinforced plastics.

The present invention is configured as described above. According to this, when reinforcing structures such as bridges and elevated roads with fiber reinforced plastic, the first and second reinforcing fibers 4 and 6 are arranged in one direction on each support sheet. The first and second unidirectionally-arranged reinforcing fiber sheets 1 and 5 provided so that the reinforcing fibers 4 and 6 can be used by impregnating the reinforcing fibers 4 and 6 with a room-temperature-curable matrix resin at the reinforcing site. Since the sheets 1 and 5 impregnated with the matrix resin are stuck around the reinforcement and left as they are, the matrix resin can be cured and the sheets 1 and 5 can be made of fiber reinforced plastic. Reinforcement with a fiber reinforced plastic can be performed with good workability without performing the complicated work of heating and curing the matrix resin in the field.

Needless to say, the reinforcing fibers 4 of the first reinforcing fiber sheet are high reinforcing fibers having an elastic modulus of 5 tons / mm ² or more, and the second reinforcing fiber sheet 6 is made of a reinforcing fiber having a breaking elongation of 1.2% or more. In addition, since the fiber-reinforced plastic is hybridized as a reinforcing fiber having a toughness that is higher than the breaking elongation of the first reinforcing fiber 4 by 20% or more, the structure is destroyed by the first reinforcing fiber 4 having high rigidity. While it is possible to increase the strength to prevent cracks easily, the second reinforcing fiber 6 having high toughness enhances the fracture toughness of the structure, thereby preventing the structure from being immediately destroyed even if it is cracked. The time to reach can be extended. Further, since the reinforcing fibers 4 and 6 are arranged in one direction, there is no reduction in the strength of the fiber-reinforced plastic as when they are crossed.

Further, since the matrix resin is cured after the reinforcing fiber sheet is attached around the reinforcing portion, the reinforcing can be performed even at the curved reinforcing portion.

Embodiment 1 A specific embodiment of the present invention will be described.

A carbon fiber is used as the first reinforcing fiber having high rigidity, and the carbon fiber is provided in one direction with a yarn weight of 175 g / m ² on the support sheet to produce a first reinforcing fiber sheet. A polyester fiber (trade name, Vectran: manufactured by Kuraray Co., Ltd.) was used as the reinforcing fiber, and the fiber was provided in one direction on the support sheet at the same yarn weight of 175 g / ² to prepare a second reinforcing fiber sheet.

The elastic modulus of the carbon fiber used was 23.5 ton / mm ² and the elongation was 1.4%, as measured by the strand strength measurement method (JIS method). The elastic modulus of the polyester fiber was 8.5 ton / mm ² and the elongation was
2.5%.

The first and second reinforcing fiber sheets are impregnated with the epoxy resin prepared as a matrix resin in a room-temperature curing type, and then bonded to the reinforcing fibers, and the matrix resin is cured by being left at room temperature to form a hybrid fiber-reinforced plastic. The test piece was used (the width of the test piece was 15 mm). Then, a test is performed by applying a vertical load to the test piece, and the load at the initial fracture and the final fracture at that time, elongation, and the like are obtained, whereby the fiber-reinforced plastic is hybridized using the unidirectionally reinforced fiber sheet according to the present invention. The effect of the conversion was investigated.

For comparison, a reinforcing fiber sheet was prepared in which the same carbon fiber as described above was provided in one direction on the support sheet with the same yarn weight of 175 g / m ² , and two sheets were stuck together after impregnation with the matrix resin. Was cured and tested in the same manner as above.

 Table 1 shows the obtained results.

In Table 1, the load at the initial break and the final break indicates the average value of seven times, and the elongation indicates the average value of five times.
The values in parentheses in these columns and the column of rigidity are CV values indicating the degree of variation. The stiffness indicates the stiffness of the entire fiber reinforced plastic and is indicated by load / elongation. The fracture energy was determined by drawing a stress-elongation-strain curve similar to that shown in FIGS. 2 and 3 and calculating the figure by triangular approximation.

As is clear from Table 1, in the case of the present invention, the fiber reinforced plastic is hybridized using a reinforced fiber sheet of carbon fiber having high rigidity and a reinforced fiber sheet of polyester fiber having high toughness. Although the load at the final break is smaller than that of the comparative example which is not hybridized using two carbon fiber reinforcing fiber sheets, the elongation and the breaking energy are about 2.5 times larger, and the reinforcing fiber starts to break. However, it did not immediately reach the final breakage, indicating that the safety when reinforcing the structure with the fiber reinforced plastic was excellent.

Effect of the Invention As described above, in the present invention, a unidirectional array reinforced fiber sheet in which first rigid fibers having high rigidity are arranged in one direction on a support sheet, and a second reinforcement having high toughness are provided. It uses a unidirectionally reinforced fiber sheet in which fibers are arranged in one direction and two types of reinforced fiber sheets, and impregnates the reinforced fibers with a room-temperature-curable matrix resin at the site of reinforcement to provide reinforcement. By adhering a reinforcing fiber sheet in which fibers are impregnated with a matrix resin around the reinforcement area and leaving it as it is, the matrix resin can be cured without the troublesome work of heating and curing the matrix resin at the reinforcement site The fiber reinforced plastic can be reinforced with good workability. Of course, the fracture strength of the structure can be increased to prevent cracks from easily occurring, and the fracture toughness of the structure can be increased to prevent the structure from being immediately destroyed even if cracks occur.

Furthermore, since the reinforcing fibers are arranged in one direction, the reinforcing strength of the obtained fiber-reinforced plastic can be improved. Further, the reinforcement can be performed even if the reinforcement portion is curved.

[Brief description of the drawings]

1 (a) and 1 (b) are cross-sectional views showing an example of first and second unidirectionally reinforced fiber sheets used in the method of reinforcing a structure according to the present invention. FIG. 2 shows one reinforcing fiber sheet provided with a high rigidity reinforcing fiber and one reinforcing fiber sheet provided with a high toughness reinforcing fiber.
It is a graph which shows typically the stress-elongation-strain curve of a fiber reinforced plastic at the time of applying a perpendicular load to the surface of a fiber reinforced plastic at the time of using and hybridizing. FIG. 3 is a graph similar to FIG. 2 when two reinforcing fiber sheets provided with reinforcing fibers having higher rigidity but lower toughness than the above are used. FIG. 4 (a) is a cross-sectional view showing one mode of arranging fiber bundles of reinforcing fibers in the reinforcing fiber sheet of FIG. 1 (a). FIG. 4 (b) is a sectional view showing the arrangement of reinforcing fibers obtained from the fiber bundle of FIG. 4 (a). FIG. 5 (a) is a cross-sectional view showing another mode of arranging the fiber bundles of the reinforcing fibers in the reinforcing fiber sheet of FIG. 1 (a). FIG. 5 (b) is a cross-sectional view showing the arrangement of reinforcing fibers obtained from the fiber bundle of FIG. 5 (a). FIG. 6 is an explanatory view showing one embodiment of a method for producing a reinforcing fiber sheet used in the reinforcing method of the present invention. FIG. 7 is a sectional view showing an embodiment of the reinforcing method of the present invention. FIG. 8 is a sectional view showing another embodiment of the reinforcing method of the present invention. FIG. 9 is a sectional view showing still another embodiment of the reinforcing method of the present invention. 1: Reinforcing fiber sheet 2: Support sheet 3: Adhesive layer 4, 6: Reinforcing fiber 4A: Fiber bundle 18: Reinforcing point 19: Matrix resin 20: Primer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E01D 22/00 E01D 19/02

Claims (4)

(57) [Claims] 1. A first unidirectionally-arranged fiber sheet in which first reinforcing fibers having high rigidity are arranged in one direction via an adhesive layer on a resin-permeable support sheet; At least one second unidirectionally-arranged fiber sheet in which second toughened second reinforcing fibers are arranged in one direction via an adhesive layer on a flexible support sheet, at least one sheet at a time. A method for reinforcing a building, characterized in that the first and second reinforcing fibers are bonded to a surface of the first reinforcing fiber after being impregnated with a room-temperature-curable matrix resin, and then the matrix resin is cured. 2. A first unidirectionally reinforced fiber sheet in which first stiffening fibers having high rigidity are arranged in one direction via an adhesive layer on a resin permeable support sheet; At least one second unidirectionally-arranged fiber sheet in which second toughened second reinforcing fibers are arranged in one direction via an adhesive layer on a flexible support sheet, at least one sheet at a time. A structure characterized in that a room-temperature-curable matrix resin is applied on the surface of the substrate and then attached, so that the first and second reinforcing fibers are impregnated with the matrix resin, and then the matrix resin is cured. Reinforcement method. 3. A first unidirectionally-arranged fiber sheet in which first rigid fibers having high rigidity are arranged in one direction via an adhesive layer on a resin-permeable support sheet; At least one second unidirectionally-arranged fiber sheet in which second toughened second reinforcing fibers are arranged in one direction via an adhesive layer on a flexible support sheet, at least one sheet at a time. And then impregnated into the first and second reinforcing fibers by infiltrating the first and second reinforcing fiber sheets with a room-temperature-curable matrix resin, and then impregnating the matrix resin with the first and second reinforcing fibers. A method for reinforcing a structure, comprising curing. 4. The first reinforcing fiber has an elastic modulus of 5 tons / mm ^2.
4. The method according to claim 1, wherein the elongation at break of the second reinforcing fiber is 1.2% or more and 20% or more than the elongation at break of the first reinforcing fiber.