JPH11324339A - Concrete reinforcing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure satisfactory concrete strength even when an edge distance is made to be small, by improving the concrete strength near a part where an anchor is placed. SOLUTION: In a concrete reinforcing method in placing an anchor 1 in a concrete building frame 15 and fixing a fitting material to the concrete building frame through the anchor 1, a fiber reinforced forming sheet 17 is put on a position corresponding to the concrete part 11 supposed to be broken by placing the anchor 1, and in such a condition, unhardened resin in the fiber reinforced forming sheet 17 is hardened to arrange and fix the sheet 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing concrete, and more particularly to a method for reinforcing concrete when an anchor is cast on a concrete frame and an attachment is fixed to the concrete frame via the anchor.

[0002]

2. Description of the Related Art A metal fitting for firmly fixing an object to a structure such as concrete is called an anchor. There are two types of anchors, "pre-install" and "post-install". The former is a method in which the concrete is set before the concrete is cast and the concrete is hardened by the adhesion resistance after the concrete is hardened. The latter is a method of perforating the concrete after hardening, and forcing friction into the hole by driving an anchor into the hole. FIG. 6 is an example of an anchor bolt for retrofit,
(A) is a partially cutaway front view, and (b) is a side view. 1a
Is a head formed in a truncated cone shape (tapered shape), 1b is a cylindrical main body in which a part of the head is fitted, and a split sleeve portion 1b-1 divided into four is formed on the head fitting side. A female screw 1b-3 is formed inside the cylindrical portion 1b-2. FIG. 7 is an explanatory view of a method of installing an anchor, and FIG.
As shown in (1), a hole 4 is drilled in the concrete 10 with a drill 3 to a predetermined depth.
(C) Thereafter, the driving rod 5 is fitted to the anchor bolt 1 and the driving rod is hit with a hammer 6. As a result, the main body 1b of the anchor bolt enters the inside of the hole toward the bottom of the hole, the relatively tapered head 1a penetrates deeply into the main body 1b, the split sleeve 1b-1 spreads, and is fixed to the concrete by a wedge effect. You. (D) After the anchor bolts are fixed as described above, the attachment 7 and the washer 8 are screwed into the female screw portion 5 with the headed bolt 2 and the attachment is completed. The maximum strength of the post-installed anchor after construction is determined by the strength of the bolt portion of the anchor and the concrete breaking strength at the anchor anchoring portion. For example, as shown in FIG. 8 (a), when the anchor 1 is cast and installed on the concrete skeleton 10, and the axial pulling force is applied thereto, the bolt of the anchor 1 is cut or the concrete skeleton 10 is cut. FIG. 8 out of 10
A portion 11 indicated by a broken line in (a) breaks in a cone shape as shown in FIG. 8 (b). By the way, the cutting of the bolt is determined by its material, and it is possible to obtain an appropriate bolt strength by using a bolt of an appropriate material.
Therefore, the maximum strength is often determined by the concrete breaking strength.

[0003] From the above, in order to sufficiently utilize the strength of the anchor, the concrete fracture shape 11 (dotted line) shown in FIG. As shown in (b), there is enough "edge"
"Anchor spacing" is required. For example, as shown in FIG. 9 (c), when the anchor 1 is installed near the edge 10a of the concrete skeleton 10, a portion 11 (shown by a broken line) where the breaking of the concrete is assumed at the maximum strength.
The anchor 1 must be installed in such a manner that the edge L10, which is the distance between the edge 10a and the anchor 1, is sufficiently secured so that the edge fits inside the edge 10a.

[0004]

However, if a sufficient margin is to be ensured, the following problem occurs.
10 and 11 referred to below show the anchor 1 in a simplified manner for simplicity. For example, as shown in FIG. 10, an anchor 1 is cast on a base concrete 15 and the base concrete 15 is inserted through the anchor 1.
When the elevated water tank 16 is installed above, if the edge L11 as described above is sufficiently secured in the base concrete 15 in order to secure the strength of the anchor 1, the base concrete 15 becomes extremely large. In addition, for example, as shown in FIG. In such a case, it is necessary to install the anchor 1 at this position. However, the anchor 1 cannot be installed close to the edge 20a because the edge L12 needs to be sufficiently secured. Eventually, the anchor 1 cannot be installed at a desired position, and an inconvenience that an object cannot be properly attached occurs.

[0005] Further, even though anchors are installed with a sufficient margin of the size considered to be sufficient, concrete breaks down in a fracture shape shown in FIG. Because of such cases, there is also a demand for improving the strength of concrete as much as possible in preparation for such a large earthquake and taking measures to prevent damage to the fixture. From the above, the object of the present invention is to be able to reinforce the strength around the concrete where the anchor is cast,
Another object of the present invention is to provide a concrete reinforcing method capable of sufficiently preventing concrete from breaking even if the edge area is reduced.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for reinforcing concrete in which an anchor is installed and an attachment is fixed via the anchor. This is achieved by adhering a reinforcing fiber molded sheet to a position corresponding to the above, curing the uncured resin in the reinforcing fiber molded sheet in this state, and arranging and fixing the sheet. In this way, if the reinforcing fiber molded sheet is attached to and fixed to a portion where the concrete is to be broken, the concrete can be reinforced, and even if the edge is reduced, the concrete can be prevented from being sufficiently broken.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of an embodiment of the present invention. FIG. 1 (a) is a perspective view of a base concrete to which the present invention is applied, and FIG. Explanatory drawing when an elevated water tank is installed, FIG. 1 (c)
1 is a perspective view showing a reinforcing fiber molded sheet (prepreg sheet) wound in a roll shape. An elevated water tank 16 (only a part is shown) is installed via an anchor 1 cast on a base concrete 15 as shown in FIG.
That is, the anchor 1 is cast from the upper surface 15b of the base concrete 15, and the leg 16 of the elevated water tank 16 is provided.
a is the anchor 1 cast on the base concrete 15
And is fixedly attached with bolts 2 via The base concrete 15 is formed in the shape of a quadrangular prism as shown in FIG. 1 (a), and a prepreg sheet 17 which is a reinforcing fiber molded sheet is formed on a side surface 15a around the four sides so as to cover the side surface 15a. is set up. The prepreg sheet 17 in the embodiment is formed by impregnating a carbon fiber aggregate with a thermosetting resin such as an epoxy acrylate resin to form a sheet.

When the elevated water tank 16 is installed as described above, as shown in FIG. 1A, the anchor 1 is first placed on each base concrete 15 from its upper surface 15b in the same manner as the conventional anchor installation method. Is installed. Next, a prepreg sheet 17 is prepared. For example, as shown in FIG. 1 (c), a prepreg sheet 17 which is formed into an elongated strip shape and wound into a roll is prepared. Then, the prepreg sheet 17 is attached to a position corresponding to a concrete breakage site assumed by the anchoring. For example, FIG.
As shown in FIG.
Then, a prepreg sheet 17 is adhered to “a” so as to cover the upper part of the side surface 15 a (at this time, a primer or an adhesive is used if necessary). At the time of sticking, the band-shaped prepreg sheet 17 is cut off at the site while appropriately cutting off the base concrete 15 according to the sticking site.
The prepreg sheet 17 is arranged in a closed annular shape so as to surround the base concrete 15 as shown in FIG. With the prepreg sheet 17 adhered in this manner, the prepreg sheet 17 is heated by a heater, hot air, electricity, or the like, and the uncured resin in the prepreg sheet 17 is cured. 15a is fixed in close contact. By fixing, the installation of the prepreg sheet 17 on the base concrete 15 is completed, and the installation of the anchor 1 is all completed. Thereafter, the elevated water tank 16 is connected via the anchor 1.
Are fixedly attached to the base concrete 15 with the bolts 2, and the installation of the elevated water tank 16 is completed.

By the way, in the prior art, a portion 11 where an axial pulling force is applied to the anchor 1 cast in the concrete body to exceed the maximum strength and break the concrete into a cone shape.
Has a size indicated by a broken line in FIG. From the viewpoint of the prior art, in order to sufficiently exert the maximum strength of the anchor 1, for example, an edge L10 as shown in FIG. 1B is required, and the size of the edge 11 is large enough to secure the portion 11 inside. Base concrete 15X (shown in phantom) should be required. On the other hand, the circumference of the base concrete 15 employed in the present embodiment is smaller than that of the base concrete 15X, and therefore, only the edge L1 smaller than the edge L10 is secured. The base concrete 1
It is large enough to protrude laterally from the edge 15c of the fifth. However, in the present embodiment, the prepreg sheet 1 is placed at a position corresponding to a concrete breakage site assumed by anchoring of the side surface 15a of the base concrete 15.
7 is applied, and therefore, the portion where the portion 11 protrudes from the base concrete 15 is the prepreg sheet 17.
The shape is reinforced by. Thus, even if only a small edge L1 is secured, the anchor 1 is subjected to a pulling load because it is reinforced by the prepreg sheet 17 (that is, the concrete rupture shape is controlled by the prepreg sheet 17). In this case, sufficient strength is secured. In addition, since the prepreg sheet 17 is installed in a closed annular shape so as to surround the base concrete 15, the base concrete 15 can be tightened and reinforced. As described above, the reinforcement of the base concrete 15 becomes more firm, and the strength of the anchor 1 can be more reliably ensured.

In the case of this embodiment, when the prepreg sheet 17 is installed, the prepreg sheet 1
Since 7 is rolled and brought to the site, it is convenient even in a small work site without taking up space. Furthermore, since the prepreg sheet 17 is formed in a long and narrow strip shape, it can be cut and pasted as appropriate in accordance with the shape of the installation site. Can be applied appropriately, and the degree of freedom of construction is extremely high. Also, the prepreg sheet 17
Is very lightweight and thin (approximately 0.2-0.4 mm thick), so that it does not interfere with the attachment and does not increase the weight that the anchor must support, which is advantageous. In the above-described example of the installation procedure of the anchor 1, the prepreg sheet 17 is installed on the base concrete 15 after the anchor 1 is cast on the base concrete 15, but as another example, first, the prepreg sheet 17 is first mounted on the base concrete 15. After installation on the base 15, the anchor 1 may be driven into the base concrete 15.

As another example, it is also possible to install a prepreg sheet 17 in the form of retrofitting as a seismic reinforcement or the like on the base concrete 15 on which the anchor 1 has already been installed by the conventional installation method. is there. For example, if the anchor 1 has already been installed by the conventional installation method on the base concrete 15 having the size indicated by the solid line in FIG. 1B, the size of the base concrete 15 is not changed, and the size of the base concrete 15 is not changed. Prepreg sheet 1
The strength of the concrete can be improved only by installing 7. Thereby, for example, the prepreg sheet 1
7 is not used, a strength equivalent to the maximum strength of the base concrete 15X indicated by the two-dot chain line in FIG. 1B can be obtained.
Will have the same safety factor as the case of using.

The prepreg sheet 17 is formed on the peripheral side surface 15a of the base concrete 15 as in the above-described embodiment.
When the prepreg sheet 17 is attached only to the anchor 1, the attachment operation of the prepreg sheet 17 can be easily performed without interfering with the anchor 1 and the like before and after the anchoring operation performed from the upper surface 15 b. In particular, the present invention can be easily used when retrofitting is performed as seismic reinforcement or the like after the attachment is already attached by the anchor 1. Further, the method is not limited to the method of sticking only to the side surface 15a,
It is also possible to affix both to the upper surface 15b. As shown in FIG. 2, when the anchor 1 (in FIG. 2, the anchor 1 is simplified for simplicity) is installed on the beam-shaped base concrete 50, the anchor 1 is placed only near the place where the anchor 1 is cast. The prepreg sheet 17 (the prepreg sheet 17 is hatched on the surface for clarity in FIG. 2) is installed on the entire horizontally extended side surface of the base concrete 50, and the base concrete 50 is entirely covered. It is also effective to reinforce over a period of time. That is, since the prepreg sheet 17 is a reinforcing fiber such as carbon fiber and serves as a tensile reinforcing material to supplement the tensile strength of concrete, the base concrete 50 is formed by supplementing such a tensile material to a concrete that is strong in compression but weak in tension. It is also very effective in preventing breakage of itself.

As shown in FIG. 3, when the anchor 1 is to be installed at a position close to the edge 20a of the wall surface 21 of the concrete skeleton 20, a mounting surface of the anchor 1 is required. The prepreg sheet 17 is set on the side surface 21a adjacent to the wall surface 21 which is the prepreg sheet.
In this case, the edge L2 between the cast anchor 1 and the edge 20a is a small one that cannot secure sufficient strength in consideration of the prior art, so that concrete breakage is assumed for each anchor 1. The part 11 (shown by a broken line) is in a state of protruding from the concrete skeleton 20 toward the edge 20a. However, concrete skeleton 2
The prepreg sheet 17 is installed on the side surface 21a of the prepreg sheet 0, so that the portion where the portion 11 protrudes from the edge 20a is reinforced by the prepreg sheet 17. Thereby, even if the edge clearance L2 is small, sufficient strength is secured when a pulling load is applied to the anchor 1. As described above, the anchor can be installed at a position close to the rim, so that the place where the attachment is attached is not limited. Regarding the installation of the prepreg sheet 17,
Site 11 where concrete breakage is assumed as shown in FIG.
In addition to sticking the prepreg sheet 17 only to the position (side surface 21a) corresponding to the above, the prepreg sheet 17 can also be stuck together with the wall surface 21 which is the casting surface of the anchor 1.

As shown in FIG. 4, when the anchor 1 is cast on the upper surface 56a of the parapet portion 56 of the roof concrete 55, and the emergency stairs 60 are installed via the anchor 1, the reinforcement of the concrete is not required. The procedure is performed in substantially the same manner as in the above-described embodiments. That is, the prepreg sheet 17 is placed on the side surface 56b of the parapet portion 56 near the placement position of the anchor 1 (the surface adjacent to the anchor placement surface 56a via the edge 56c). Alternatively, the prepreg sheet 17 is installed on the parapet section 56 on which the anchor 1 is already installed for the purpose of seismic reinforcement and the like. As described above, it is possible to prevent concrete breakage in the parapet portion 56 at the site where the anchor 1 is placed, and the safety factor is increased.

Further, as shown in FIG. 5, an anchor 1 is cast on a wall surface 65a of a concrete wall 65 having an opening 66 formed thereon, and the surface grid is fitted to the opening 66 via the anchor 1 through the anchor 1. Also when the 67 is installed, the reinforcement of the concrete is performed in substantially the same procedure as in each of the above-described embodiments. That is, the prepreg sheet 17 is placed on the end surface of the wall 65 facing the opening 66 and at the position of the end surface 65b near the driving position of the anchor 1 (position near the edge 65c). Thereby, safety can be ensured even if the anchor 1 is driven at a position near the edge 65c.

[0016]

As described above, according to the present invention, at the position corresponding to the concrete breakage site assumed by the placement of the anchor,
The reinforcing fiber molded sheet is applied, and in this state, the uncured resin in the reinforcing fiber molded sheet is cured to arrange and fix the sheet, so that the concrete near the anchoring position can be reinforced. . In other words, since the concrete part that is supposed to break by applying a pulling load to the anchor is reinforced with a reinforcing fiber molded sheet,
The concrete strength is improved as much as possible, so that sufficient concrete strength can be ensured even if the edge area is reduced. In addition, when the concrete body is a base concrete, the edge can be reduced, so that the base concrete itself can be made as small as possible, which is convenient. Further, since the reinforcing fiber molded sheet is lighter and thinner than an iron plate or the like, it is advantageous because it does not interfere with the attachment and does not increase the weight that the anchor must support. Furthermore, since the reinforcing fiber molded sheet also has appropriate flexibility, it can be folded and rolled up and can be compactly handled, and can be appropriately deformed according to the shape of the concrete body to be attached and installed. is there. Further, according to the present invention, since the reinforcing fiber molded sheet does not need to be attached to the anchor placing surface, the attaching operation of the reinforcing fiber molded sheet can be performed before or after the anchor placing operation without any problem. be able to. In particular, it can be easily used when retrofitting, for example, as a seismic reinforcement in preparation for a large earthquake after the attachment is already attached by the anchor.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention.

FIG. 2 is an example (part 1) of concrete reinforcement according to the present invention.

FIG. 3 is a concrete reinforcement example (part 2) of the present invention.

FIG. 4 is a concrete reinforcement example (part 3) of the present invention.

FIG. 5 is a concrete reinforcement example (part 4) of the present invention.

FIG. 6 is an example of a retrofit anchor bolt.

FIG. 7 is an explanatory view of a method of installing an anchor.

FIG. 8 is an explanatory view of concrete breakage.

FIG. 9 is an explanatory view of an anchor placing position that does not cause concrete breakage.

FIG. 10 is an explanatory diagram of a problem when a margin is secured;

FIG. 11 is an explanatory diagram of another problem in a case where a margin is secured;

[Explanation of symbols]

 1 Anchor 15 Concrete body (base concrete) 15a Adjacent surface (side surface) 15b Anchor casting surface (upper surface) 15c Edge portion (edge) 17 Reinforced fiber molded sheet (prepreg sheet) 20: Concrete body (concrete body) 20a: Edge part (edge) 21: Anchor placement surface (wall surface) 21a: Adjacent surface (side surface)

Claims (1)

[Claims] 1. A method for reinforcing concrete in which an anchor is installed and an attachment is fixed via the anchor, wherein a reinforcing fiber molded sheet is attached to a position corresponding to a concrete breakage site assumed by the installation of the anchor. Then, in this state, the uncured resin in the reinforcing fiber molded sheet is cured, and the sheet is arranged and fixed.