JPH1150673A - Reinforcing structure for concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb compression force to prevent bucking of a steel plate so as to enable sure transmission of tension force by fixing a cross section L- shaped steel plate disposed on the lower end of a pier on a footing through a spacer having deformation follow-up property. SOLUTION: The plastic hinge area H of prescribed height is left on the outer periphery of the base part of a concrete pier 1 to adhere a continuous fiber sheet such as a continuous carbon fiber to fix the horizontal part 9a of a cross section L-shaped steel plate 9 by anchor bolts 7 and nuts 11 buried in a footing 3 through a spacer 13 so as to tightly adhere the vertical part 9b of the steel plate 9 on the continuous fiber sheet 5. The spacer 13 is composed of flexible material of a few millimeters having follow-up property of rubber material, silicon material, epoxy resin material and the like. Thereby in the case where the pier 1 receives bending moment by earthquake, compression force acted on the steel plate 9 is absorbed to release the steel plate 9 from the burden of the compression force to prevent buckling of the steel plate 9 so as to surely transmit tension force to the footing 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing structure for reinforcing a reinforced concrete structure (hereinafter referred to as a concrete structure) such as a pier, a chimney, a silo or the like by bonding or winding a continuous fiber reinforcing material such as carbon fiber. .

[0002]

2. Description of the Related Art Seismic retrofitting has been prosperous in the wake of the Hyogoken Nanbu Earthquake.
In addition to the conventional reinforced concrete winding method and the steel plate bonding method, a reinforcing method using a continuous fiber reinforcing material such as carbon fiber developed by the present applicant has attracted attention.

[0003] In this method, a carbon fiber sheet or a strand as a continuous reinforcing material is used to bend in a material axis direction on a member surface to perform bending reinforcement, and to bond or wind in a direction perpendicular to the member axis to perform shear reinforcement. , To increase the proof stress of the member.

Prior to the Hyogoken-Nanbu Earthquake, such a reinforcing method using a continuous fiber reinforcing material had been accumulated as an earthquake-resistant reinforcing method for chimneys and a reinforcing method for pier paragraphs. However, since the Hyogoken-Nanbu Earthquake, it has been adopted as a bending reinforcement of the pier base for the purpose of increasing the strength of concrete structures, especially piers themselves.

A conventional reinforcing method using a continuous fiber reinforcing material is as follows.
For example, as shown in FIG.
The continuous fiber sheet 102 is adhered to the outer periphery of a, and is fixed to the footing 105 by the anchor bolt 104 via the steel plate 103 having an L-shaped cross section, thereby transmitting the stress from the continuous fiber sheet 102 to the footing 105. . In the reinforcing method shown in the figure, the sheet 102 is adhered until it contacts the upper end surface of the footing 105.

However, such a structure has the following problems. A) Although the continuous fiber reinforcement has a higher strength than the rebar,
Since the elongation is small, the structure becomes poor in the deformation performance (toughness) of the entire pier. b) Damage occurs in the concrete at the base of the pier (formation of a so-called plastic hinge region), and this damage increases (the plastic hinge region expands). Is insufficient and the continuous fiber reinforcement peels off before the required yield strength is exhibited.

On the other hand, as shown in FIG. 3, it is known that the continuous fiber sheet 102 is bonded to the footing 105 while leaving a plastic hinge region H having a predetermined height from the upper end surface thereof. According to this structure, in the damaged area of the pier base 101a (the area where the plastic hinge is formed), the continuous fiber reinforcement does not exist and is not bonded thereto, so that the plastic hinge is formed after bending yield. Since the bond between the continuous fiber reinforcement and the concrete does not break, the bending strength increases and the toughness improves (September 1996, Japan Society of Civil Engineers 51st Annual Scientific Supporting Association, “V-476 Carbon Fiber Experimental Study on Seismic Retrofit of RC Bridge Pier ").

[0008]

However, even the conventional reinforcing method shown in FIG. 3 has the following technical problems. That is, the continuous fiber sheet 1
02 is transmitted from the continuous fiber sheet 102 to the steel plate 103, the anchor bolt 104, and the footing 105, but acts on the steel plate 103 because the steel plate 103 is rigidly fixed to the upper end of the footing 105. The steel plate 103 may buckle due to the compressive force, and the tensile force may not be transmitted reliably.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Even if a compressive force acts on a steel material for fixing a continuous fiber reinforcing material, the steel material does not buckle, and the continuous fiber reinforcing material is not buckled. An object of the present invention is to provide a reinforcing structure for a concrete structure that reliably transmits a tensile force borne by a member.

[0010]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 comprises a concrete base portion and a concrete structure mainly standing upright on the base portion. A reinforcing structure for a concrete structure, wherein a continuous fiber reinforcement is bonded or wound around a periphery of the concrete structure, leaving a plastic hinge region having a predetermined height from an upper end surface of the base portion,
In order to transmit the tensile force borne by the continuous fiber reinforcement to the base portion side, a steel material closely supporting the side surface of the reinforcement material is fixed to an anchor fixed to the base portion, and the base portion and the steel material A spacer having a predetermined thickness made of a soft material such as a rubber material, a silicon material, an epoxy resin material or the like having a deformability following property is interposed therebetween. According to the present invention, the tensile force borne by the continuous fiber reinforcement during the occurrence of an earthquake is transmitted from the continuous fiber reinforcement to the steel material, the anchor, and the base portion, but the steel material and the base portion have deformation followability. Since a soft material spacer is interposed, almost no compressive force acts on the steel material, so that the steel material does not buckle.

Further, the invention according to claim 2 is characterized in that a gap is formed between the base portion and the steel material instead of interposing the spacer. According to the present invention, it is possible to obtain the same effect as the first aspect of the present invention, without interposing a spacer, thereby reducing the number of man-hours for component management.

Further, the invention according to claim 3 is characterized in that the strength of the anchor or the steel material is designed to reach the bending strength earlier than the breaking strength of the continuous fiber reinforcement. According to the present invention, damage to the base portion can be minimized, and repair of the base portion can be minimized.

The invention according to claim 4 is characterized in that the concrete structure is mainly made of steel pipe concrete. ADVANTAGE OF THE INVENTION According to this invention, a reliable restraint force is obtained, the amount of conversion into the amount of belt rebar and main rebar is extremely large, and the plastic hinge region can be made very short.

[0014]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a preferred embodiment of the present invention. In the figure, a continuous fiber sheet 5 (continuous fiber reinforcing material) of continuous carbon fiber or the like is formed on the outer periphery of a base 1a of a pier 1 except for a plastic hinge region H having a predetermined height from an upper end surface of a footing 3 (base portion). The horizontal part 9a of a steel plate 9 (steel material) having an L-shaped cross section is fixed by a nut 11 to an anchor bolt 7 embedded in the footing 3 and protruding above its upper end surface. The vertical portion 9b of the steel plate 9
The lower part thereof faces the plastic hinge region H of the pier base 1a,
The upper part is in close contact with the side surface of the continuous fiber sheet 5.

The above configuration is the same as that of the prior art shown in FIG. 3, but in the present invention, the footing 3
Is characterized in that a spacer 13 having a thickness of several millimeters made of a soft material such as a rubber material, a silicon material, an epoxy resin material or the like having a deformable property is interposed between the upper end surface of the steel plate 9 and the horizontal portion 9a of the steel plate 9. .

According to the above configuration, the tensile force borne by the continuous fiber sheet 5 when an earthquake occurs is transmitted from the continuous fiber sheet 5 to the steel plate 9, the anchor bolt 7, and the footing 3. Since the spacer 13 made of a soft material having deformation followability is interposed between the end face and the end face,
Since the compressive force of the steel plate 9 is absorbed by the spacer 13 and the compressive force hardly acts on the steel plate 9, the steel plate 9 does not buckle, and the tensile force is transmitted to the footing 3 without fail.

In the damaged area (plastic hinge forming area H) of the concrete of the pier base 1a, the continuous fiber sheet 5 does not exist and is not bonded to the continuous fiber sheet 5, so that it is the same as the prior art shown in FIG. Furthermore, since the adhesion between the continuous fiber sheet 5 and the concrete does not break when the plastic hinge is formed after the bending yield, the bending strength and the toughness are high.

Further, when the toughness is to be improved, the steel plate 9 is hardly subjected to a compressive force and is considered to share the tensile force only when a tensile force is applied. Therefore, the bending strength of the pier base 1a is increased. And the toughness can be further improved as compared with the prior art shown in FIG.

In the present embodiment, it is preferable that the strength of the anchor bolt 7 or the steel plate 9 is designed to reach the bending strength before the breaking strength of the continuous fiber sheet 5.

That is, by setting the yield strength of the anchor bolt 7 lower than the yield strength of the continuous fiber sheet 5 at break and the yield strength of the steel plate 9, the ductility of the anchor bolt 7 in the plastic hinge region H can be improved. Gives sufficient toughness. In this case, the sectional strength of the plastic hinge region H is determined by adding an anchor bolt 7 minutes to the existing section. When an earthquake occurs, the anchor bolt 7 is damaged, and damage to other parts such as the footing 3 can be suppressed. Therefore, the repair is completed only by replacing the anchor bolt 7 alone.

Further, by setting the yield strength of the steel sheet 9 lower than the yield strength of the continuous fiber sheet 5 at break and the yield strength of the anchor bolt 7, the ductility of the steel sheet 9 in the plastic hinge region H is reduced. Sufficient toughness is obtained.
In this case, the sectional strength of the plastic hinge region H is determined by adding 9 minutes of the steel plate to the existing section. The repair is completed only by replacing the steel plate 9 damaged at the time of the occurrence of the earthquake, and the replacement of the steel plate 9 can be performed more easily than the anchor bolt 7.

In this embodiment, the spacer 13 is interposed between the upper end surface of the footing 3 and the horizontal portion 9a of the steel plate 9. However, a gap may be simply provided without interposing the spacer 13. In this case, the horizontal portion 9 of the steel plate 9
It is preferable to fasten a nut to the lower part of a.

In the present invention, the plastic hinge portion is preferably formed of a steel pipe (preferably a normal steel pipe without ribs). The reason is as follows. Firstly, as a member for restraining concrete and preventing its crushing when a plastic hinge is formed, a band reinforcing bar having a hook at a corner of a pier cross section is often used, but the reinforcing bar of the hook is formed on the outer side. While the steel pipe is easily bent and loses its binding force, the steel pipe has no hooks and is continuous, and the amount of conversion to the steel bar is extremely large. In addition, since the amount of conversion of the steel pipe into the amount of main rebar is extremely large, the plastic hinge can be stopped in a very short region of the pier (about the pier cross-section height).

Further, the present invention is not limited to the one described in the embodiment, but may be a continuous fiber strand in place of the continuous fiber sheet 5 or other concrete such as a chimney or a silo. Needless to say, it can be applied to a structure.

[0026]

As is apparent from the above description, the reinforcing structure for a concrete structure according to the present invention not only increases the bending strength and toughness but also enhances the steel material for fixing the continuous fiber reinforcing material. Even if a compressive force acts, the steel material does not buckle, and the tensile force borne by the continuous fiber reinforcing material can be reliably transmitted to the base portion.

Further, damage to the base portion can be minimized, and repair of the base portion can be minimized (claim 3). In addition, the amount converted to the amount of the main rebar is extremely large, and the plastic hinge region can be extremely short (claim 4).

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a preferred embodiment of a reinforcing structure for a concrete structure according to the present invention.

FIG. 2 is a cross-sectional view showing a preferred embodiment of a conventional concrete structure reinforcing structure.

FIG. 3 is a cross-sectional view showing a preferred embodiment of another conventional reinforcing structure for a concrete structure.

[Explanation of symbols]

 Reference Signs List 1 bridge pier (1a base) 3 footing H plastic hinge area 5 continuous fiber sheet (continuous fiber reinforcement) 7 anchor bolt 9 steel plate (steel) (9a horizontal part, 9b vertical part) 11 nut 13 spacer

Claims (4)

[Claims] 1. A concrete structure reinforcement structure comprising a concrete base portion and a concrete structure main body integrally erected on the base portion, wherein the concrete structure main body is provided on an outer periphery of the concrete structure main body. The continuous fiber reinforcement is bonded or wound while leaving a plastic hinge region having a predetermined height from the upper end surface of the base portion, and the tension of the continuous fiber reinforcement is transmitted to the base portion side to transmit the tensile force borne by the continuous fiber reinforcement. A steel material that firmly supports the side surface is fixed to an anchor fixed to the base portion, and a soft material such as a rubber material, a silicon material, an epoxy resin material, or the like that is deformable between the base portion and the steel material. A reinforcing structure for a concrete structure, wherein a spacer having a predetermined thickness is interposed. 2. Instead of interposing the spacer,
The reinforcing structure for a concrete structure according to claim 1, wherein a gap is formed between the base portion and the steel material. 3. The reinforcement of a concrete structure according to claim 1, wherein the strength of the anchor or the steel material is designed to reach a bending strength before the breaking strength of the continuous fiber reinforcement. Construction. 4. The reinforcing structure for a concrete structure according to claim 1, wherein the main part of the concrete structure is made of steel tube concrete.