JP6179978B2 - Side fastening PC steel bar protrusion protection method - Google Patents

Description

The present invention relates to a laterally-tightening PC steel bar protrusion protection method for reinforcing a concrete structure to which prestress is applied based on a PC steel bar being embedded in a tensioned state.

    Conventionally, as one method of strengthening a concrete structure, a method of applying prestress by embedding a PC steel bar in a tensioned state has been used. However, in such a concrete structure, if the embedded PC steel bar breaks down due to corrosion, the PC steel bar pops out from the surface of the concrete structure by releasing the tension. There is a risk that Therefore, a steel plate or the like is appropriately disposed on the surface of the structure to prevent the PC steel bar from jumping out as described above (see, for example, Patent Documents 1 and 2).

    FIG. 2A is a cross-sectional view showing an example of a conventional reinforcing structure for a concrete structure. Reference numeral 200 in the figure indicates a concrete structure, and reference numeral 201 is embedded in the concrete structure 200. The reference numeral 202 denotes a steel plate disposed to prevent the PC steel rod 201 from popping out in the unlikely event that the PC steel rod 201 breaks, and the reference numeral 203 denotes a fiber for attaching the steel plate 202. A reinforced sheet is shown.

Japanese Patent No. 2742675 Japanese Patent No. 3625484

    By the way, when constructing a reinforcing structure as described above, a chemical anchor (not shown) must be used to support the steel plate 202 until the fiber reinforced sheet 203 is attached. (For example, exploration of reinforcing bars for specifying the anchor placement position, drilling of the surface of the concrete structure, curing of chemical anchors, etc.) is required, and there is a problem that the construction period is lengthened accordingly.

    Further, as shown in detail in FIG. 2 (b), the edge of the steel plate 202 has a sharp shape (that is, a vertical shape with respect to the surface of the concrete structure). There is a problem that a gap portion A is formed between the surface and the fiber reinforced sheet 203 and air is accumulated, or the corners of the steel plate 202 are in contact with the fiber reinforced sheet 203 so that the sheet 203 is easily broken. In order to solve such a problem, a method of filling the gap A with putty material has been adopted. However, in that case, there is a problem that a time for applying and curing the putty material is required, and the work period is lengthened accordingly.

An object of the present invention is to provide a laterally-tightening PC steel bar protrusion protection method capable of solving the above-described problems.

The invention according to claim 1 is illustrated in FIGS. 1 (a) and 1 (b), and is concrete that is prestressed based on the PC steel bar (2) being buried in a tensioned state. In the side-tightening PC steel bar protrusion protection method to reinforce the structure (3),
Arranging the receiving member (10) along the surface of the concrete structure (3);
A step of supporting the receiving only member (10) support member (11),
With
Said receiving member (10) includes a plurality of mesh layers at least one layer is made of metal (101, ...) and, in the mesh layer (101) so as to be disposed on the side facing the concrete structure (3) A resin layer (100) formed by impregnation is laminated and configured.

    The invention according to claim 2 is the invention according to claim 1, wherein the plurality of mesh layers (101,...) Are arranged so that at least one end of the receiving member (10) has a stepped shape. It is characterized by that.

    The invention according to claim 3 is the invention according to claim 1 or 2, wherein the plurality of mesh layers (101, ...) are made of a stainless steel mesh layer, a bi-directional aramid fiber sheet, a stainless steel mesh layer, and two Directional aramid fiber sheets are arranged and arranged in order from the side close to the concrete structure (3).

    Note that the numbers in parentheses are for the sake of convenience indicating the corresponding elements in the drawings, and therefore the present description is not limited to the descriptions on the drawings.

    According to the first aspect of the invention, since the resin layer is formed on the outer surface of the receiving member (that is, the surface on the concrete structure side), the outer surface becomes compatible with the adhesive, and the adhesive is used. Thus, the receiving member can be firmly attached to the concrete structure. Therefore, it is not necessary to use the chemical anchor as described in the conventional example, and various processes for placing the chemical anchor (for example, the exploration of reinforcing bars for specifying the anchor placing position, the surface of the concrete structure, etc. No drilling or chemical anchor curing is required, and the construction period can be greatly shortened.

    According to the invention concerning Claim 2, since it becomes difficult to produce a clearance gap between a concrete structure surface and the said supporting member, it is not necessary to use a putty material like the past. Therefore, time for applying and curing the putty material becomes unnecessary, and the work period can be shortened accordingly.

    According to the invention which concerns on Claim 3, a receiving member can have the same tensile strength as the conventional steel plate, and can prevent the protrusion of a PC steel bar exactly. Further, since the stainless steel mesh layer disposed on the side close to the concrete structure is first subjected to the impact force when the PC steel bar breaks, it is possible to more effectively prevent the PC steel bar from popping out. Furthermore, since the stainless steel mesh layer and the aramid fiber sheet are used, the receiving member can be made excellent in corrosion resistance.

Fig.1 (a) is sectional drawing which shows an example of the reinforcement structure of the concrete structure based on this invention, The figure (b) is an expanded sectional view which shows an example of the structure of a receiving member. FIG. 2 (a) is a sectional view showing an example of a conventional reinforcing structure for a concrete structure, and FIG. 2 (b) is a partially enlarged sectional view thereof.

    Hereinafter, an embodiment of the present invention will be described with reference to FIG.

    The reinforcing structure of a concrete structure according to the present invention is illustrated by reference numeral 1 in FIG. 1 (a), and prestress is applied based on the fact that the PC steel bar 2 is buried in a tensioned state. The PC steel bar 2 jumps out from the concrete structure 3 even when the PC steel bar 2 breaks due to corrosion (jumps rightward in the drawing). Is suppressed or prevented.

The concrete structure reinforcing structure 1 according to the present invention is, as illustrated in FIG.
A member (hereinafter referred to as a “receiving member”) 10 disposed along the surface of the concrete structure 3 so as to receive the PC steel rod 2 when the PC steel rod 2 jumps out;
A support member 11 that supports the receiving member 10 at a predetermined position (that is, a position along the surface of the concrete structure 3 where the PC steel rod 2 may jump out);
It is constituted by. In addition, it is sufficient for the above-described receiving member 10 to be close to the surface of the concrete structure 3, and it does not matter whether or not it is in contact with the surface.

As shown in detail in FIG.
A plurality of mesh layers 101, 102, 103, 104 that are arranged in a stacked state and at least one layer is made of metal (preferably made of stainless steel);
A resin layer 100 disposed on the side facing the concrete structure 3 (the left side in the figure);
Are laminated. Here, as the above-mentioned resin layer 100, an epoxy resin layer can be exemplified. In addition, the mesh layer 101 in this specification does not mean only a layer having a so-called mesh shape (mesh), but a plurality of through holes (through holes that can be impregnated with resin). It is a concept that includes even a sheet-like material having. Furthermore, the above-described support member 11 may be made of a known material such as an aramid fiber sheet or a nylon sheet, and the edge of the support member 11 may be bonded to the surface of the concrete structure 3 with a known adhesive.

    According to the present invention, since the resin layer 100 (for example, epoxy resin layer) is formed on the outer surface of the receiving member 10 (that is, the surface on the concrete structure side), the outer surface is bonded with an epoxy or acrylic adhesive. Thus, the receiving member 10 can be firmly attached to the concrete structure 3 using the adhesive. Therefore, it is not necessary to use the chemical anchor as described in the conventional example, and various processes for placing the chemical anchor (for example, the exploration of reinforcing bars for specifying the anchor placing position, the surface of the concrete structure, etc. No drilling or chemical anchor curing is required, and the construction period can be greatly shortened. Further, since the receiving member 10 is the mesh layer 101 except for the resin layer 100, the resin layer 100 can be formed simply by impregnating the resin (for example, epoxy resin). Simple. In addition, in order to prevent displacement in the surface direction of the receiving member 10 until it is fixed by the support member 11 (that is, displacement in the direction along the surface of the concrete structure), a simple displacement stop (for example, the length is You may use the plastic pin about 10-15 mm.

By the way, an aramid fiber sheet (for example, a bi-directional aramid fiber sheet) may be used for the mesh layers 101,..., And the plurality of mesh layers 101,. Layer), and
An aramid fiber sheet (for example, a bi-directional aramid fiber sheet);
It is good to comprise by laminating | stacking alternately. Thereby, the receiving member 10 can have the same tensile strength as the conventional steel plate, and can prevent the projection of the PC steel rod 2 appropriately.

In this case, from the side close to the concrete structure 3 (left side in FIG. 1 (a))
-Stainless steel mesh layer (see reference numeral 101)
・ Bidirectional aramid fiber sheet (see 102)
-Stainless steel mesh layer (see reference 103)
・ Bidirectional aramid fiber sheet (see reference numeral 104)
It is good to arrange | position in order of and to obtain the tensile strength equivalent to a steel plate. Further, when a metal mesh layer is arranged on the concrete structure 3 side, the mesh layer first receives an impact force when the PC steel rod 2 is broken, and the PC steel rod 2 is more effectively ejected. Can be prevented. Furthermore, when a stainless steel mesh layer and an aramid fiber sheet are used, the receiving member 10 can be made excellent in corrosion resistance.

    By the way, the size of the plurality of mesh layers 101 is such that at least one end portion of the receiving member 10 (meaning the end portion of the laminate composed of the plurality of mesh layers 101,...) Has a stepped shape. It is good to set the arrangement position. In the case of such a stepped shape, a gap is not easily generated between the surface of the concrete structure and the support member 11 (that is, the sheet-like support member 11 arranged so as to cover the receiving member 10), There is no need to use putty materials as in the past. Therefore, time for applying and curing the putty material becomes unnecessary, and the work period can be shortened accordingly. In addition, it is good to make the edge part of the perimeter of the receiving member 10 into step shape as mentioned above.

DESCRIPTION OF SYMBOLS 1 Reinforcement structure of concrete structure 2 PC steel bar 3 Concrete structure 10 Receiving member 11 Support member 100 Resin layer 101, ... Mesh layer

Claims (3)

In the side-tightening PC steel bar protrusion protection method to reinforce the concrete structure to which prestress is applied based on the PC steel bar being buried in a tensioned state,
Arranging the receiving member along the surface of the concrete structure;
A step of supporting the receiving only member by a support member,
With
The receiving member is formed by laminating a plurality of mesh layers, at least one layer of which is made of metal, and a resin layer formed by impregnating the mesh layer so as to be disposed on the side facing the concrete structure. Composed of,
Side-tightening PC steel bar protrusion protection method characterized by this. The plurality of mesh layers are arranged such that at least one end of the receiving member has a stepped shape,
The laterally-tightening PC steel bar protrusion protection method according to claim 1. The plurality of mesh layers are configured by sequentially arranging a stainless steel mesh layer, a bi-directional aramid fiber sheet, a stainless steel mesh layer, and a bi-directional aramid fiber sheet from the side close to the concrete structure,
The laterally tightening PC steel bar protrusion protection method according to claim 1 or 2, characterized in that.

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