JP2001146846A - Concrete-reinforcing structure by tensed multilayer reinforcing fiber sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcing structure of a concrete member capable of easily carrying out work execution and improving bending bearing force and tenacity of the concrete member, a restraining effect of cracking and bearing force against peeling of a fiber material. SOLUTION: A plural number of reinforcing fiber sheets 45a-45d different in length from each other are accumulated and arranged from a surface of a concrete member 41 in order of size, and tensile force is introduced to at least one of the reinforcing fiber sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete member reinforcing structure using a reinforcing fiber sheet.

[0002]

2. Description of the Related Art Conventionally, as a reinforcing structure for a concrete member, it has been known that a reinforcing fiber sheet to which a tension is introduced is bonded to a lower surface or a side surface of the concrete member.

For example, FIG. 4 shows a concrete bridge girder 41 erected on a pier 42, and a plurality of reinforcing fiber sheets 43 are adhered to the lower surface of the bridge girder 41. In this reinforcing structure, one or a plurality of reinforcing fiber sheets 43 are tensioned by a tensioning device, and then bonded so as to be laminated on the surface of the concrete member by a resin adhesive. However, due to the tension in the reinforcing fiber sheet in such a reinforcing structure, as shown in FIG. 3A, the shear stress is concentrated on the end portion of the reinforcing fiber sheet 43, the adhesive layer, and the surface layer of the concrete. It is known that the reinforcing fiber sheet 43 peels off as the tension increases. Even if the end of the reinforcing material does not peel off due to the tension itself, there is a possibility that the fiber reinforced sheet will peel off with an increase in the external load.

In order to prevent the end portion of the reinforcing fiber sheet from being peeled off, it has been proposed to fit the end portion of the sheet as shown in FIGS. That is, in FIG. 5, the non-tensioned reinforcing fiber sheet 1 is wrapped around both ends of the reinforcing fiber sheet 13 which is tensioned and adhered to the lower surface of the concrete member 40.
In FIG. 6, a steel plate 16 is crimped to both ends of a similar reinforcing fiber sheet 13 with bolts 17.

[0005]

In a concrete member arranged like a bridge girder 41 in FIG. 4, the bending stress is largest at the center and decreases toward both ends. Since the reinforcing fiber sheet is adhered over the entire length of the concrete member, both ends of the reinforcing fiber sheet are wasted in structural strength.

Further, as shown in FIGS. 5 and 6, when the both ends of the reinforcing fiber sheet are fixed by the steel plate 16 and the bolts 17 or the non-tensile reinforcing fiber sheet 15, the cost is increased because the number of materials and processes are increased. There is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a concrete member capable of easily performing construction and improving the resistance to peeling of a fibrous material. The object of the present invention is to provide a reinforcing structure.

[0008]

According to the present invention, there is provided a concrete member in which reinforcing fiber sheets having different lengths are bonded to at least two layers of a concrete member, and a tension is applied to at least one of the reinforcing fiber sheets. Is provided.

Further, in the present invention, a plurality of reinforcing fiber sheets having different lengths are stacked and arranged from the surface of a concrete member in a long order, and a reinforcing member for reinforcing a concrete member in which a tension is introduced into at least one of the reinforcing fiber sheets. A structure is provided.

Here, it is preferable that the plurality of reinforcing fiber sheets having different lengths are laminated so that their respective centers are substantially aligned.

As the reinforcing fiber sheet, a reinforcing fiber strand or a reinforcing fiber sheet impregnated with a matrix resin and cured can be used. Here, as the reinforcing fiber strand or the reinforcing fiber sheet, organic fibers such as carbon fiber, aramid fiber, PBO fiber, polyester fiber, and high-strength polypropylene, metal fibers such as steel, boron, titanium, and copper, and glass fibers are used. It is possible to use any selected fiber or a hybrid type in which a plurality of the fibers are mixed.

The matrix resin may be at least one kind of at least one of a room temperature curing epoxy resin, a thermosetting epoxy resin, a polyester resin or a vinyl ester resin, a polyamide resin or a polycarbonate resin, and a radical reaction resin such as MMA. It may be included.

Further, the reinforcing fiber sheet may be a sheet in which reinforcing fibers are arranged in a sheet shape in one direction or in multiple directions, a cloth in which reinforcing fibers are woven, or a mat.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited thereto.

FIG. 1 is a side view showing an example in which the concrete member reinforcing structure of the present invention is applied to a bridge girder. A bridge girder 41 as a concrete member is erected on piers 42, 42.
On the lower surface of the bridge girder 41, a plurality of reinforcing fiber sheets 45a to 45d having different lengths are adhered and laminated in order of length. Here, the plurality of reinforcing fiber sheets 45a to 45d are stacked and arranged so that the center is aligned with the center of the bridge girder 41, and at least one tension force is introduced into the reinforcing fiber sheets 45a to 45d, but it is preferable. Tension is introduced to all the other reinforcing fiber sheets 45b to 45d except the longest reinforcing fiber sheet 45a bonded to the concrete surface.
From the viewpoint of effective use of the reinforcing material, all reinforcing fiber sheets 4
Tension is introduced at 5a-45d. Optimally, a relatively low tension is introduced into the reinforcing fiber sheet directly adhered to the lowermost concrete surface, compared to other adhesive layers, to minimize peeling of the lowermost reinforcing fiber sheet.

In the bridge girder 41 supported at both ends as shown in the figure, the bending stress acts most at the center and decreases toward the both ends, but in the reinforcing structure as described above, the bridge girder 41 moves from both ends toward the center. Since the number of layers of the reinforcing fiber sheet is configured to be increased, it is possible to most effectively counter bending stress in terms of structural strength. Further, since the reinforcing fiber sheet is arranged at the end of the bridge girder 41 as shown in FIG. 1, the shear stress is dispersed as shown in FIG. 3 (b), so that the stress concentration at the end of the reinforcing fiber sheet is considerably reduced. You. Therefore, certain peeling can be prevented. If necessary, it is used in combination with the edge reinforcement method as shown in FIGS.

Next, regarding the method of forming the reinforcing structure of the concrete member, all the reinforcing fiber sheets 45a to 45
A description will be given of a reinforcing structure in which a tension is introduced into d as an example. First, tension is applied to the longest reinforcing fiber sheet 45a, which is fixed to the lower surface of the bridge girder 41 by an adhesive. Next, an adhesive is applied to the surface of the fixed reinforcing fiber sheet 45a, tension is applied to the second long reinforcing fiber sheet 45b, and the second reinforcing fiber sheet 45b is adhered on the reinforcing fiber sheet 45a in an arrangement in which the respective centers are aligned. . Similarly, by sequentially laminating and bonding from a long reinforcing fiber sheet, a reinforcing structure is formed.

FIG. 2 shows an embodiment other than FIG.
FIG. 2A is a side view, and FIG. 2B is an enlarged sectional view. Here, a plurality of reinforcing fiber sheets 46a to 46c
Are adhered and laminated in order of length, at least one of them is subjected to tension, and the uppermost layer is covered with a non-tensile reinforcing fiber sheet 46d longer than the lowermost reinforcing fiber sheet 46a. . In the reinforcing structure having such a configuration, particularly, the effect of preventing the end reinforcement and the end separation can be obtained by integrating the reinforcing fiber sheet ends.

The reinforcing fiber sheets 45a to 45d
A so-called CFRP sheet can be used as the reinforcing fiber sheets 46a to 46d. That is, the CFRP sheet is a carbon fiber reinforced plastic formed by impregnating carbon fibers as reinforcing fibers with a matrix resin such as an epoxy resin.
A-based fibers, pitch-based fibers, and the like can be used.
This CFRP sheet is, for example, a carbon fiber sheet (manufactured by Nippon Steel Composite Co., Ltd., FORCA tow sheet “FT”).
S-C1-20 ").

[Brief description of the drawings]

FIG. 1 is a side view of a concrete reinforcing structure according to an embodiment of the present invention.

2A is a side view of a concrete reinforcing structure different from FIG. 1, and FIG. 2B is an enlarged sectional view of FIG.

FIG. 3A is a diagram showing a shear stress in a conventional concrete reinforcing structure, and FIG. 3B is a diagram showing a shear stress in a concrete reinforcing structure of the present invention.

FIG. 4 is a side view showing a conventional concrete reinforcing structure.

FIG. 5 is a perspective view showing a conventional example.

FIG. 6 is a perspective view showing a conventional example different from FIG.

[Explanation of symbols]

 41 concrete member 45a-45d reinforced fiber sheet 46a-46d reinforced fiber sheet

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takeshi Kanda 2-1-1, Hirakawacho, Chiyoda-ku, Tokyo Inside Oriental Construction Co., Ltd. (72) Akira Kobayashi 3-8 Nihonbashi Kobunacho, Chuo-ku, Tokyo Nippon Steel Corporation F term (reference) in Composite Corporation 2E163 FA12 FD02 FD25 FD50 2E164 AA05 DA01 2E176 AA01 BB29

Claims (2)

[Claims] 1. A reinforcing structure for a concrete member in which reinforcing fiber sheets having different lengths are bonded to at least two layers of a concrete member, and tension is applied to at least one of the reinforcing fiber sheets. 2. A concrete member reinforcing structure in which a plurality of reinforcing fiber sheets having different lengths are stacked and arranged from the surface of a concrete member in a long order, and tension is introduced into at least one of the reinforcing fiber sheets.