JPH07139090A - Reinforcing and repair method for concrete construction member - Google Patents

Abstract

PURPOSE:To provide a concrete construction member capable of increasing resistance against shear, torsion and bending forces, and increasing even toughness for both a reinforced concrete member and prestressed concrete member. CONSTITUTION:A bonding material such as epoxy resin is used for FRP fabric and the fabric is wound in laminar state around the external surface of a cured concrete member so as to be integrated therewith. Pre-stress is, then, introduced to form a cylindrical body 3. Otherwise, the orientation of the fabric in a single layer is changed and wound in laminar state to form the body 3, or an existing pipe such as an FRP tube or a steel tube is used as the body 3. Concrete is placed in the body 3, and pre-stress is introduced to the concrete via a tension member or chemically. In this case, the deformation of the concrete is constrained in a direction orthogonal with the application of the stress, thereby introducing compression pre-stress along three axes.

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 structural members that can be applied as a new construction or repair / reinforcement method for all concrete structures such as columns and beams.

[0002]

2. Description of the Related Art Conventionally, a prestressed concrete structure contributes to an increase in cracking load such as bending, shearing and twisting, but hardly contributes to an increase in fracture strength.

Further, a concrete structural member which prevents the concrete from rapidly breaking at the time of breaking, that is, which improves the toughness, has not been developed yet.

Further, since the steel material corrodes, arranging it outside the concrete member increases the maintenance cost, so it has not been considered so much.

Recently, rod-shaped continuous fiber rods (FRP rods) have been developed and put into practical use by solidifying carbon fibers, aramid fibers, glass fibers and synthetic resin fibers with epoxy resin or the like, and using them, reinforced concrete beams and Research on prestressed concrete beams has become popular.

Therefore, the applicants also used this FRP rod to provide a prestressed concrete beam by the same reinforcing method as that of conventional steel materials, and conducted bending, shearing and twisting tests of the beam.

As a result, regarding the shearing and torsional strength of the beam, the amount of deformation of the beam becomes large due to the difference in Young's modulus between the FRP rod and the steel material and the difference between the fiber direction and the stress acting direction. It was confirmed that even if the material was reinforced with an FRP rod, the effect equivalent to that of the steel material was not obtained, and the shear resistance and the torsion resistance were reduced.

[0008]

Therefore, the present invention is
A concrete structure, which is a reinforced concrete member,
It is an object of the present invention to provide a method for reinforcing a concrete structural member capable of improving toughness by combining shearing, twisting, and bending resistance with respect to both prestressed concrete members.

[0009]

In order to achieve the above object, the present invention provides a woven fabric (Fiber Reinforced Pl-as) made of FRP.
tic sheet) using a binder such as an epoxy resin, and winding it in layers so that the woven fabric is integrated with the outer circumference of the hardened concrete member, and then introducing prestress, or epoxiing the FRP woven fabric with epoxy. Using a binder such as resin,
A tubular body formed by winding one layer by changing the fiber direction, or using an existing FRP or steel pipe to form a tubular body and placing concrete in the tubular body, By introducing prestress into the concrete with a tension material or a chemical method, the deformation of the concrete is constrained in the orthogonal direction, and a compressive prestress in the triaxial direction is introduced. The woven fabric made of FRP is constructed by using one or more selected from fibers of carbon, aramid, glass and synthetic resin, and these fibers are arranged in the longitudinal direction, the transverse direction or the oblique direction, or Composed of a combination of these, and the tension material is F
The RP rod is made of PC steel, and the steel is made of anticorrosion material.

[0010]

In the operation of the present invention, the outer periphery of the concrete member is entirely reinforced with FRP or steel, and the prestress is introduced in the uniaxial direction to prevent the concrete from spreading in the direction perpendicular to the axis. Restrained by the tubular body,
Generates three-dimensional compressive stress in concrete.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings FIG. 1, FIG. 2 and FIG.
A method of introducing a prestress after winding a woven fabric (1) using a binder such as an epoxy resin in a layered manner so that the woven fabric is integrated with the outer periphery of a hardened concrete member (2), or A tubular body (3) formed by winding one layer by changing the fiber direction, or an existing pipe made of FRP or steel is used to form a tubular body (3 '). 3) Or, by placing concrete in the tubular body (3 ') and introducing prestress to the concrete by a tension material (4) or a chemical method, the concrete is poured in the direction (X) at right angles. It comprises a method for reinforcing a concrete structural member characterized by restraining deformation and introducing compressive prestress in three axial directions.

The woven fabric (1) made of FRP is constructed by using one or more selected from carbon, aramid, glass fiber and synthetic resin fiber, and these fibers are arranged in the longitudinal direction, the transverse direction or the oblique direction, Alternatively, it is constructed by weaving a combination of these.

Further, the tension member (4) is an FRP rod,
It is selected from PC steel.

The tubular body (1) may have a circular cross section, a rectangular cross section, or any other shape, and the tension member (4) is
Either FRP rod or PC steel material may be used. One or a plurality of rods may be arranged at the center of the sectional view or at an eccentric position according to the design, and in the concrete, reinforcing bars (5) may be arranged as reinforcing bars and FRP rods. There are cases.

[0015]

According to the present invention, the outer periphery of the concrete member is
By reinforcing the entire surface with FRP or steel and introducing prestress in the uniaxial direction, it is restrained by the tubular body that the concrete tries to spread in the direction perpendicular to the axis, and three-dimensional compressive stress is generated in the concrete. .

As a result, the strength of the concrete subjected to the three-dimensional compressive stress becomes 1 to several times higher than the uniaxial compressive strength, and the bending, shearing, torsional proof strength and toughness of the member are greatly increased.

Further, since the outside of the concrete member is entirely covered, even if the internal concrete is cracked, the rigidity is not sharply lowered, and the ingress of rainwater, seawater, air, etc. can be blocked, so that the deterioration of the concrete can be prevented. Corrosion of steel bars in concrete and concrete can also be prevented, and the maintenance cost of conventional concrete structures can be greatly reduced.

In particular, when the surface of the concrete member is reinforced with FRP, it has an extremely beneficial effect such as being useful in a corrosive environment of steel materials and in marine structures.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing another embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing an embodiment of the present invention.

FIG. 4 is an enlarged side view showing still another embodiment of the present invention.

FIG. 5 is an enlarged side view showing still another embodiment of the present invention.

[Explanation of symbols]

 1 FRP woven fabric 2 Hardened concrete member 3 Cylindrical body 3'Cylindrical body 4 Tension material 5 Reinforcing bar X Right angle direction

[Procedure amendment]

[Submission date] December 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Reinforcement and repair method for concrete structural members <br />

[Claims]

Detailed Description of the Invention

[0001]

The present invention relates to a pillar, regarding reinforcement and repair how <br/> method of concrete structural members can be applied as a new or reinforcing and repair method of any concrete structures such as beams.

[0002]

2. Description of the Related Art Conventionally, a prestressed concrete structure contributes to an increase in cracking load such as bending, shearing and twisting, but hardly contributes to an increase in fracture strength. Also, the ones built so far have a useful life
To meet, to cause early deterioration due to external factors,
Reinforcement and repair will be required in the future due to the increase in load due to the revision of the document.
It becomes important.

Further, a concrete structural member for preventing concrete from being rapidly broken at the time of breaking, that is, enhancing the toughness against earthquake has not been developed yet.

Further, since steel material corrodes, arranging it outside the concrete member increases maintenance costs, and it has not been considered so far.

Recently, rod-shaped continuous fiber rods (FRP rods) have been developed and put into practical use by solidifying carbon fibers, aramid fibers, glass fibers and synthetic resin fibers with epoxy resin or the like, and using them, reinforced concrete beams and Research on prestressed concrete beams has become popular.

Therefore, the applicants also used this FRP rod to provide a prestressed concrete beam by the same reinforcing method as that of conventional steel materials, and conducted bending, shearing and twisting tests of the beam.

As a result, regarding the shearing and torsional strength of the beam, the amount of deformation of the beam becomes large due to the difference in Young's modulus between the FRP rod and the steel material and the difference between the fiber direction and the stress acting direction. It was confirmed that even if the material was reinforced with an FRP rod, the effect equivalent to that of the steel material was not obtained, and the shear resistance and the torsion resistance were reduced.

[0008]

Therefore, the present invention is
A concrete structure, which is a reinforced concrete member,
It is an object of the present invention to provide a method for reinforcing and repairing a concrete structural member capable of improving toughness by combining shearing, twisting, and bending resistance with respect to both prestressed concrete members.

[0009]

In order to achieve the above object, the present invention provides a woven fabric (Fiber Reinforced Pl-as) made of FRP.
tic Sheet) in using a binder material, such as epoxy resin, existing
Alternatively, after pre-stressing is introduced by winding the woven fabric in layers so that the woven fabric is integrated with the outer periphery of a newly set hardened concrete member, or a binder such as epoxy resin is used for several layers of FRP woven fabric, A tubular body formed by winding one layer by changing the fiber direction, or using an existing pipe made of FRP or steel to form a tubular body, and concrete is poured into the tubular body, depending on the tendons in concrete
Prestressed or expanded concrete
And the like are cast into the tubular body, and by introducing a prestress by a chemical method, the deformation of the concrete is constrained in the direction perpendicular to the prestress, and a compressive prestress in the triaxial direction is introduced. It consists of a method of reinforcing and repairing structural members . The woven fabric made of FRP is formed by weaving one or more fibers selected from carbon, aramid, glass, and synthetic resin fibers in any of the longitudinal direction, the transverse direction, the oblique direction, or a combination thereof. The tension material is made of FRP rod and PC steel material . Furthermore, outside
The part-reinforced steel material is composed of a corrosion-resistant material. Also prestress
The method of introducing is using a tension material such as FRP rod and PC steel .
Or a chemical method using an expansive material.

[0010]

In the operation of the present invention, the outer periphery of the concrete member is entirely reinforced with FRP or steel, and the prestress is introduced in the uniaxial direction to prevent the concrete from spreading in the direction perpendicular to the axis. Restrained by the tubular body,
Generates three-dimensional compressive stress in concrete. like this
The prestressed concrete member manufactured in
By applying to beams and columns, bending resistance and shear resistance
Can significantly increase force, torsional strength and toughness
Since it can be constructed, it can have an earthquake-resistant structure. Also deteriorated
Have a space around the outside of the concrete structure with an FRP sheet
It is rolled up in layers and in the middle of expanded concrete or
Is a three-axis chemi
It becomes possible to introduce calprestress and its consequences
As a result, the concrete strength of existing structures has been improved and deteriorated.
The structure can be effectively reinforced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings FIG. 1, FIG. 2 and FIG.
A method of introducing a prestress after winding a woven fabric (1) using a binder such as an epoxy resin in a layered manner so that the woven fabric is integrated with the outer periphery of a hardened concrete member (2), or A tubular body (3) formed by winding one layer by changing the fiber direction, or an existing pipe made of FRP or steel is used to form a tubular body (3 '). 3) Or, concrete is placed in the tubular body (3 ') and the concrete is pressed with a tension material (4) .
Introducing a tress or expanding concrete into the tubular body
Reinforcement of concrete structural member characterized by restraining the deformation of concrete in the direction (X) at right angles by introducing prestress by a chemical method by placing it in the concrete and introducing compressive prestress in three axial directions. Composed of methods.

Prestressing by chemical methods (chem
Calprestress) uses a strong expansive material for concrete
To introduce prestress using cement
When the expansive material reacts and hardens, concrete becomes triaxial
Since it expands in the opposite direction, its ability to deform laterally is tight.
Stronger than when using upholstery. That is, PC tension material
When using prestress after hardening concrete
If the Poisson's ratio of concrete in the elastic region is 0.2,
Since the size is small, the lateral deformation capacity is small. That
Therefore, an extremely large prestress was introduced to the plastic region.
Only when the stress is increased, the lateral deformation increases and the restraint effect increases.
The fruits will be demonstrated. Therefore, chemical pressed
It is easier to obtain a large three-axis restraint in the case of
Wear.

Further, FRP made of fabric (1) is carbon, aramid, glass fiber and single selected from synthetic resin fiber or plurality of fibers in the longitudinal direction, either laterally or oblique direction, or, these It is composed of woven fabrics in combination.

Further, the tension member (4) is an FRP rod,
It is selected from PC steel.

The tubular body (1) may have a circular cross section, a rectangular cross section, or any other shape, and the tension member (4) is
Either FRP rod or PC steel material may be used. One or more rods may be arranged at the center position of the sectional view or at an eccentric position according to the design, and in the concrete, reinforcing bars (5) may be used as reinforcing bars or FRP rods. May be placed.

[0016]

According to the present invention, the concrete member (RC.PC) is constructed.
FRP sheet or steel pie around the outside of any structure)
Reinforcing the entire outer circumference with a slab and introducing prestress in the uniaxial direction restrains the concrete from trying to spread in the direction perpendicular to the axis . As a result , three-dimensional compressive stress is introduced into the concrete,
Or tighten the existing structure inside, and
And toughness can be significantly increased. Therefore resistant
It is possible to make an extremely excellent structure even after an earthquake.
It

That is, the conventional prestressed concrete
In the case of beams, press only about 1/3 the stress of uniaxial compressive strength
Although it could not be introduced as a tress, in the case of the present invention,
Pre-stress over uniaxial compressive strength due to axial restraint
The bending strength of the beam member is 1.5 to 2 because
And the deflection increases 5 to 10 times. This axis
Apparent concrete due to prestressing over compressive strength
The tensile strength of the sheet is greatly increased by the amount of prestress.
The shear strength or torsional strength of the beam is 3-5 of the conventional case.
Can be doubled. Therefore, according to the present invention
Reinforcement method is brittle fracture, which is shear fracture and torsion fracture
It is possible to prevent breakage and significantly increase toughness, and
This is an epoch-making method that is extremely superior as a structure.

Further, since the outside of the concrete member is entirely covered, even if the internal concrete is cracked, the rigidity does not drop sharply and the ingress of rainwater, seawater, air, etc. can be blocked, so that the deterioration of the concrete can be prevented. Corrosion of steel bars in concrete and concrete can also be prevented, and the maintenance cost of conventional concrete structures can be greatly reduced.

In particular, when the surface of a concrete member is reinforced with FRP, it has an extremely beneficial effect such as being useful in a corrosive environment of steel materials and in marine structures.

However, the characteristics of the three-dimensionally constrained concrete
Performance is the same as that of conventional concrete structures.
Since it is significantly different from the characteristics of cleats,
There are some cases that cannot be dealt with by the conventional design method. That is,
The three-dimensional compression constraint ensures that the compressive strength depends on the degree of external constraint.
At the same time, the deformability is also increased several times. Such a big
Kina deformation far exceeds the plastic region in conventional concrete.
It is an area that has crossed over and has already been destroyed. Obey
Since this is a field that no one has experienced so far,
Analysis and design methods are expected and needed.
Becomes

According to the result of the compression test, the internal concrete
There is a large difference in proof strength depending on whether or not the
Come on. That is, when there is no adhesion, when there is adhesion
The yield strength is about 1.3 times larger than that of the conventional products. this
Similarly, in terms of points, we will establish analysis and design methods in the future.
Some research is expected and needed.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing another embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing an embodiment of the present invention.

FIG. 4 is an enlarged side view showing still another embodiment of the present invention.

FIG. 5 is an enlarged side view showing still another embodiment of the present invention.

[Explanation of Codes] 1 FRP woven fabric 2 Hardened concrete member 3 Cylindrical body 3'Cylindric body 4 Tension material 5 Reinforcing bar X Right angle direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuhei 1 at 450 Yamane-cho, Higashi-ku, Hiroshima City, Hiroshima Prefecture Kyokuto Kogyo Co., Ltd. Yamane Dormitory (72) Inventor Shusho Yamamoto 3-26, Kurakake, Asakita-ku, Hiroshima No.23

Claims (4)

[Claims] 1. A binding material such as an epoxy resin is used for a FRP woven fabric, and the woven fabric is wound in layers so as to be integrated with the outer periphery of a hardened concrete member, and then prestress is introduced, or A tubular body formed by changing the fiber direction of one layer and wound in layers, or an existing FRP or steel pipe is used to form a tubular body, and concrete is poured into the tubular body, and the concrete is poured into the concrete. A method for reinforcing a concrete structural member, characterized in that prestress is introduced by a tension material or a chemical method, the deformation of concrete is constrained in the direction perpendicular to the prestress, and a compressive prestress in the triaxial direction is introduced. 2. An FRP woven fabric is constructed by using one or a plurality of fibers selected from carbon, aramid, glass and synthetic resin, and these fibers are arranged in a longitudinal direction, a transverse direction or an oblique direction, Alternatively, the method for reinforcing a concrete structural member according to claim 1, wherein the method is woven by combining these. 3. The method for reinforcing a concrete structure member according to claim 1, wherein the tension member is made of an FRP rod or a PC steel material. 4. The method for reinforcing a concrete structural member according to claim 1, wherein the steel pipe is made of an anticorrosive material.