KR101435624B1 - Structural Reinforcing methods of Concrete Structures for Flexural, Shear and Seismic by using Multi-directional Carbon Fibre Laminates and Mechanical Anchor - Google Patents

Abstract

The present invention relates to a performance reinforcing method of a concrete structure for being flexural, sheared, and seismic using a carbon fiber laminate produced in multiple directions and a mechanical anchor, which can operate performance reinforcing operations of a concrete structure for being sheared, flexural, and seismic at the same time. Provided is the performance reinforcing method of the concrete structure for being flexural, sheared, and seismic using a carbon fiber plate and a mechanical anchor produced in multiple directions, which can improve seismic properties according to the shear and flexural tensile reinforcement through the multi-directional carbon fiber laminate and the mechanical anchor and in particular, can remove obstacles to obstruct convenience of the operation and the durability of the concrete structure by being formed excluding the position of reinforcement bars which are embedded within the concrete structure when the mechanical anchor is installed.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of reinforcing a concrete structure using a carbon fiber plate and a mechanical anchor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing a bending, shearing, and seismic performance of a concrete structure using a carbon fiber plate and a mechanical anchor manufactured in a multi-direction, which can simultaneously perform shearing, bending tensile and seismic reinforcement of a concrete structure.

Generally, reinforced concrete structure methods include the attachment method and the cross-sectional extension method.

Here, the adhesion method includes a steel plate attachment method, a fiber sheet reinforcement method, and a fiberboard reinforcement method.

The steel plate attaching method is a method of reinforcing by using a steel plate. The weight of the steel plate is large, and heavy equipment is required at the time of construction.

In addition, there is concern about corrosion of the steel sheet itself, and there is a problem of interfacial delamination due to lack of air permeability due to sealing phenomenon.

In addition, the fiber sheet reinforcing method has a problem in that it is difficult to construct the fiber sheet in comparison with the reinforcing performance, and the quality is influenced by the skill of the operator.

In addition, the front surface construction lacks air permeability and is difficult to maintain.

In addition, the fibrous plate reinforcement method has excellent material properties, but its adhesion performance with the structure to be reinforced depends only on the epoxy adhesive.

Particularly, in the case of full construction, lack of ventilation is difficult to maintain.

To overcome these limitations, separate reinforcing steel and reinforced materials with breathability are being developed.

Meanwhile, the above-mentioned cross-sectional extension method is a method of reinforcing a concrete structure by additionally providing a cross section in addition to a concrete structure, such as a steel material addition method, a reinforcement material purchase method, and a concrete deposition method.

The double concrete deposition method is a method widely used for flexural reinforcement or shear reinforcement. It is a method of grouting the base material, spraying it by shotcrete method, and reinforcing the concrete by putting or spraying high-performance concrete mortar with good fluidity and adhesion It is a public law.

However, depending on the site conditions, there is a problem in adhesion between the concrete structure and the added mortar, which is often peeled off, so that it is difficult to obtain a sufficient reinforcing effect.

In addition, due to the limitation of the internal space, it is often impossible to apply it in practice.

In order to solve such problems, Korean Registered Patent No. 10-1013088 (Jan. 28, 2011) "Simultaneous bending and shearing reinforcement method of concrete structures" has been proposed.

In the above patent, a reinforcing material is provided at a portion where a bending stress of a concrete structure is generated, and an anchor is inserted at a portion where a shearing stress acts, so that shear reinforcement is performed within a range of 30 to 150 degrees with respect to a crack length .

However, in the case of the above-mentioned registered patent, there is a problem that the shear reinforcement is deteriorated because shear reinforcement is performed by merely inserting an anchor when shear reinforcement.

In order to solve the above-mentioned problems, the method of reinforcing the bending, shearing, and seismic performance of a concrete structure using the carbon fiber plate and the mechanical anchor manufactured in the multi-direction according to the present invention includes: In particular, the object of the present invention is to remove the elements that impede the ease of operation and the durability of the concrete structure by avoiding the position of the reinforcing bar embedded in the concrete structure when introducing the mechanical anchor, .

It is a further object of the present invention to provide an apparatus and a method for securing a shear reinforcement structure in which a shear reinforcement can be performed by tightening a portion of a shear crack by using a washer and a nut when introducing a mechanical anchor for shear reinforcement, And it is an object of the present invention to enable a washer and a nut to be tightened after introducing a washer in a triangular shape when inserting a mechanical anchor.

In the present invention, a multi-directional carbon fiber board is installed to reinforce the concrete structure, and a mechanical anchor is provided at a portion where the shear crack is generated. The mechanical anchor acts to support the multi-directional carbon fiber board together with the shear reinforcement, Reinforcement, shear reinforcement, and reinforcement work for improving seismic performance due to this can be done at once.

In addition, when the direction of the shear crack is checked during the shear reinforcement, mechanical anchors are inserted in a direction perpendicular to the direction, and the efficiency of shear reinforcement is improved. When introducing the multi-directional carbon fiber plate for bending reinforcement, The load bearing capacity can be increased.

In addition, the selection of the insertion position of the mechanical anchor during shear reinforcement can improve the workability by preventing the deterioration due to the damage of the concrete structure by forming the shear reinforcement groove by confirming the position of the reinforcement reinforcement embedded in the concrete structure.

In addition, when the shear reinforcement is applied, the bolts and washers are sequentially combined with the mechanical anchors to tighten the shear cracks. In addition, when the shear crack occurs in the slanting line, the shape of the washer is deformed, It is a useful invention that can smoothly tighten through.

1 is a perspective view showing a multi-directional carbon fiber board according to the present invention;
2 is a cross-sectional view showing a construction state of a concrete structure using a carbon fiber plate and a mechanical anchor manufactured in multiple directions according to the present invention, in a method of reinforcing a bending, shearing, and seismic performance of the concrete structure.
3 is a state view showing a shear reinforcement state using a triangular washer according to the present invention.
Fig. 4 is a schematic view showing a bending tensile test of an unreinforced RC-T beam. Fig.
Fig. 5 is a schematic view showing a bending tensile test of an RC-T beam after reinforcing a multi-directional carbon fiber board by an epoxy bonding method; Fig.
Fig. 6 is a schematic view showing a bending tensile test of an RC-T beam after reinforcing an epoxy-bonded multi-directional carbon fiber plate + both ends with an anchor bolt;
FIG. 7 is a schematic view showing a bending tensile test of an RC-T beam after reinforcing by anchoring at a certain interval in a multi-directional carbon fiber board epoxy bonding + shear zone.
FIG. 8 is a schematic view showing a bending tensile test of an RC-T beam after reinforcement by anchoring at four places of anchor bolts at both ends and anchor bolts at four ends of a multi-directional carbon fiber board epoxy.
9 is a graph showing the results of the tests in Figs. 4 to 8. Fig.

Hereinafter, the reinforcing method of the present invention will be described in more detail with reference to the accompanying drawings.

First, the shear reinforcement range confirmation step is performed.

In the step of checking the shear reinforcement range, the range of the shear crack S generated in the concrete structure C is visually checked. When the shear crack S is confirmed, the shear crack S is formed in the concrete structure C through the precise diagnosis. And the shear reinforcement position and the range are set.

Then, the shear crack directionality confirmation step is performed.

In the step of confirming the direction of shear cracking, the direction of the shear crack generated on the surface of the concrete structure (C) is checked to measure the angle of the shear crack. In the step of confirming the shear reinforcement range, S) is generated, it is possible to finish by measuring the direction (angle) of the shear crack S.

Next, an anchor positioning step for inserting a mechanical anchor A1 for shear reinforcement of the shear crack S generated on the surface or inside of the concrete structure C confirmed through the step of confirming the shear reinforcement range is performed.

In this anchor positioning step, nondestructive inspection is performed within the range of the shear crack (S) of the concrete structure (C), and the position of the reinforcing bar embedded in the concrete structure (C) This is done to install the damaged mechanical anchor (A1).

Next, when the pre-irradiation work is completed as described above, foreign matters on the surface of the concrete structure (C) are removed, and in some cases, a flat work and a cleaning work are performed to perform a concrete structure rearrangement step so that a sound base surface can be formed.

Thereafter, the multi-directional carbon fiber board 1 to which the adhesive E is applied is attached to the concrete structure C having the surface arranged.

1, the carbon fiber sheet 1 (hereinafter, referred to as a "multi-directional carbon fiber sheet") produced in the multi-direction has a first carbon fiber sheet 1a and a second carbon fiber sheet 1a, A second carbon fiber plate 1b disposed on the upper and lower surfaces of the first carbon fiber sheet 1a and having a slope of +45 relative to a direction in which the carbon fiber yarn of the first carbon fiber sheet 1a extends, And a third carbon fiber plate 1c formed so as to have a slope of -45 relative to a direction in which the carbon fiber fiber of the first carbon fiber sheet 1a extends.

That is, a second carbon fiber sheet 1b having an orientation of +45 degrees is laminated on the first carbon fiber sheet 1a in the longitudinal direction, and a second carbon fiber sheet 1b having a directionality of -45 degrees is formed on the lower side of the first carbon fiber sheet 1a. 3 carbon fiber boards 1c are stacked.

Particularly, although not shown in the drawings, a third carbon fiberboard sheet 1c is further formed on the second carbon fiberboard sheet 1b stacked on the first carbon fiberboard sheet 1a, and the first carbon fiberboard sheet 1a The second carbon fiber sheet 1b may be further formed on the lower side of the third carbon fiber sheet 1c formed on the lower side of the first carbon fiber sheet 1c to improve the strength.

The multi-directional carbon fiber sheet 1 is formed such that the first carbon fiber sheet 1a accounts for 80 to 90 wt% of the total weight and the remaining second and third carbon fiber sheets 1b and 1c accounts for 10 to 20 wt% And the lowest tensile strength is 2200 MPa and the lowest elastic modulus is 160 GPa.

In particular, although not shown in the drawing, a film may be attached to the multi-directional carbon fiber board 1.

Since the multi-directional carbon fiber board (1) employs carbon fiber boards having carbon fiber yarns extended in various directions, it prevents the multi-directional carbon fiber board (1) from being opened or broken even when forming grooves in a groove forming step And it is possible to improve the load-bearing capacity against loads acting in various directions.

The adhesive (E) applied to the surface of the multi-directional carbon fiber board (1) is formed such that the amount of the adhesive (E) applied to the surface of the multi-directional carbon fiber board (1) The adhesive (E) was applied in a substantially round shape.

This is because when the multi-directional carbon fiber board 1 is attached to the concrete structure C, the central portion of the multi-directional carbon fiber board 1 is first pressed to be attached to the surface of the concrete structure C, A part of the adhesive E is released from the multidirectional carbon fiber board 1 to cause waste of the adhesive E and the adhesive E to be dropped on the surface of the adhesive agent E or the concrete structure C ) Of the work area is buried in the work area.

Particularly, when the multi-directional carbon fiber board (1) is attached to the concrete structure (C) by pressing the center portion first, the amount of the adhesive (E) remaining in the center portion when the amount of the adhesive It is also possible to prevent a phenomenon in which a uniform adhesive force can not be formed due to a small amount of adhesive.

Next, after attaching the multi-directional carbon fiberboard 1 to the surface of the concrete structure C, grooves are formed in the concrete structure C and the multi-directional carbon fiberboard 1 (groove forming step).

At this stage, the attachment grooves h2 for enhancing the adhesive force between the shear reinforcement grooves h1 and the multi-directional carbon fibers 1 for the shear reinforcement and accordingly the load-bearing forces are formed.

First, in the case of the shear reinforcement groove (h1), it is formed in the concrete structure (C) where the position is selected through the anchor positioning step. In this case, depending on the angle at which the shear crack (S) And is formed at an angle at right angles.

At this time, the number, depth and diameter of the front end reinforcement grooves h1 may vary depending on the value designed in the reinforcement design.

The shear reinforcement grooves h1 are primarily used for shear reinforcement due to the shear crack S generated in the concrete structure C but are not limited to the bending tension due to the support of the multi- And can also be used as an application to improve the weight of the container.

In addition, in the case of the attachment groove h2, the multi-directional carbon fiber plate 1 is already supported by the shear reinforcement grooves h1. However, the multi-directional carbon fiber plate 1 is selected at a position capable of enhancing the load- .

Particularly, in the case of both ends of the multi-directional carbon fiberboard 1, it is necessary to form the end portions of the multi-directional carbon fiberboard 1 because the early detachment may occur when the flexural tensile of the concrete structure C occurs. It can be varied depending on the design value at the time of construction.

Also, in the case of a portion where a shear moment acts on the multi-directional carbon fiber plate 1 except for both end portions, the number and position are selected according to the designed value.

Here, in the present invention, a shear reinforcement groove h1 is formed.

Therefore, when the position and the number of the attachment grooves h2 are selected, it is preferable not to be formed for the durability of the concrete structure C when the distance is adjacent to the front end reinforcement groove h1.

Next, the mechanical anchor A1 and the anchoring bolt A2 are provided in the front end reinforcement groove h1 and the attachment groove h2 formed in the groove forming step as described above.

Thereafter, the washer W and the nut N are sequentially tightened to the mechanical anchor A1 and the anchor bolt A2, and then the nut N is tightened. (Shear crack tightening step)

The washer W and the nut N formed on the mechanical anchor A1 form a frictional force on the mechanical anchor A1 to pull the mechanical anchor A1 from the inside of the concrete structure C toward the surface direction So that the mechanical anchor A1 can act as a shear reinforcing member in addition to the effect of reinforcing the shear reinforcement itself.

In the case of the washer W and the nut N installed in the anchoring bolts A2, it plays a role to improve the adhesion of the multi-directional carbon fiber boards 1. However, as described above, the shear cracks S) to be displayed on the screen.

In particular, in the case of the mechanical anchor A1, as described in the above-mentioned groove forming step, the shear reinforcement groove S is formed in the oblique direction so as to be perpendicular to the direction of the shear crack S, that is, the tightening ability of the mechanical anchor A1 is lowered even though the mechanical anchor A1 is tightened through the normal nut N and the washer W. In this case,

Therefore, in the present invention, such a problem can be solved through the washer W having a triangular shape.

The washer W is configured such that the upper side thereof forms the same angle as the shear crack S in a state in which the washer W is in contact with the concrete structure C and even if the shear reinforcement groove h1 is formed in the oblique direction, N act to influence the mechanical anchor A1.

When the mechanical anchor A1 is coupled to the shear reinforcement groove h1 for shear reinforcement in the anchor inserting step, the shear reinforcement grooves h1 are filled with a filling material F made of mortar or epoxy resin ) May be further formed.

The tightening of the nut (N) in the step of tightening the shear crack may be performed by using a mechanical anchor (A1) or anchoring bolt A2 can be performed within a range in which shearing does not occur.

That is, when the mechanical anchor A1 or the anchoring bolt A2 is used as M10, it is preferable to perform a tightening operation with a torque of about 50 Nm.

Particularly, a mechanical anchor A1 or an anchor bolt A2 is formed by forming a cap (not shown) that can surround the mechanical anchor A1 or the anchoring bolt A2 after the nut N and the washer W are coupled to each other. It is possible to prevent corrosion of the nut N and the washer W and to prevent the shear reinforcement grooves h1 or the attachment grooves h1 formed in the concrete structure C for inserting the mechanical anchor A1 or the chemical anchor A2, the epoxy resin E1 is further wrapped around the mechanical anchor A1 or the anchor bolt A2 between the multi-directional carbon fiber board 1 and the washer W in order to prevent corrosion that may occur due to the inflow of water into the anchor bolt A2. Or may be applied.

As described above, according to the present invention, the introduction of the multi-directional carbon fiber boards 1 and the mechanical anchors A1 enables the simultaneous shearing, flexural reinforcement, and seismic performance improvement of the multi-directional carbon fiber boards 1, Even if the grooves are formed through the application, the function of the multi-directional carbon fiber board 1 for increasing the load bearing capacity in various directions can be maintained.

Especially, shear reinforcement can be effectively performed by forming a mechanical anchor in proper position and direction through the directional inspection of the shear crack (S) and the inspection of the reinforcing bar. By using the washer (W) and the nut (N) In addition to the role of gathering the openings due to the crack (S), when the direction of the shear crack (S) is diagonal, the effect of tightening the nut (N) smoothly by introducing the triangular washer .

Meanwhile, the effect of the anchoring bolt (A) on the bending tension will be described with reference to FIGS. 4 to 9,

First, FIG. 4 is a schematic view of a bending tensile test of an unreinforced RC-T beam, with reference to FIG. 5 for a RC-T beam test method (Beam 1) without reinforcement.

As shown in FIG. 9, the result of the test method of FIG. 4 shows that the concrete is broken at a load (P) of 60 kN × 2, and the beam is deformed before being broken due to plastic deformation after plastic deformation. Big.

FIG. 5 is a schematic view of a flexural tensile test of an RC-T beam after reinforcing the multi-directional carbon fiber board by an epoxy bonding method. Referring to FIG. 5, (Beam 2), as shown in FIG. 9, can be found to be broken at a load (P) of 80 kN × 2, and in such a state, breakage occurs before the plastic deformation, The deformation of the beam occurs less frequently and the concrete is detached, causing brittle fracture.

FIG. 6 is a schematic view showing a bending tensile test of an RC-T beam after reinforcement of an epoxy bolt + anchor bolt with a multi-directional carbon fiber plate epoxy. Referring to FIG. 6, (Beam 3) as shown in FIG. 9 was obtained by attaching with the adhesive (E) and fixing both ends of the multi-directional carbon fiber board (1) with an anchor bolt (A) And the damage occurs after the reinforcing steel is plastic-deformed, so that the deformation of the beam occurs before the breakage.

Also, even after the concrete breakage, the beam can support the load. At both ends fixed by the anchoring bolts (A), small deformation of the multi-directional carbon fiber board (1) occurs due to increase of deformation of the beam, The falling of the structure C does not occur.

FIG. 7 is a schematic view showing a bending tensile test of an RC-T beam after reinforcing six anchor rings at a predetermined interval in a multi-directional carbon fiberboard epoxy bonding + shear zone. Referring to FIG. 7, The fiber board 1 was attached with the adhesive E and the six bolts B were fixed at a fixed interval on the both side shear zones where the shear warp occurred. The results are shown in FIG. 9, , And the damage (P) 103 kN x 2, and the same action as in (Beam 5) described later occurs.

FIG. 8 is a schematic view showing a bending tensile test of an RC-T beam after reinforcement by anchoring at four places of anchor bolts with a multi-directional carbon fiber plate epoxy + two anchor bolts at both ends. After the multi-directional carbon fiber boards 1 were attached with the adhesive E and both ends of the multi-directional carbon fiber boards 1 were fixed with an anchor bolts A, 9 shows the results of the experiment (Beam 5) in which the anchoring bolts (A) are further fixed. In the result (Beam 5), it can be seen that breakage occurs at a load (P) of 117 kN × 2 and is fixed by the anchoring bolts The deterioration of the concrete by the directional carbon fiber board 1 is prevented, and the brittle fracture of the beam does not occur.

Also, it can be seen that the load-carrying capacity is increased and the safety factor is improved by fixing the multi-directional carbon fiberboard 1 with the anchoring bolts A in the shearing area.

At this time, the reinforced beam shows ductility.

On the other hand, in the case of the multi-directional carbon fiber board 1 according to the present invention, since the multi-directional carbon fiber sheet 1 has a structure in which carbon fibers are arranged in multiple directions, the multi-directional carbon fiber board 1 is not opened or broken even if a hole is formed .

The above-mentioned multi-directional carbon fiber board 1 has a structure in which carbon fiber yarns are arranged in various directions, so that the resistance against the strength and the bending can be considerably increased.

In addition, when the multi-directional carbon fiber boards 1 are formed, the ratio of the first carbon fiber boards 1a is increased so that the ability to cope with the bending stress increases, thereby exerting an excellent effect in preventing deformation of the concrete structure C.

That is, the results are summarized in the following table.

[RC-T beam test result] Reinforcement method Breaking load No reinforcement 60 kN x 2 Attach multi-way carbon fiber board to epoxy 80kN x 2 Installed multi-directional carbon fiber board with epoxy + Installed both anchor bolts (2 places) 92 kN x 2 Installed multi-directional carbon fiber board with epoxy + Anchoring (6 places) at regular intervals in shear zone 103 kN x 2 Mounted with epoxy multi-way carbon fiber plate + Both ends anchor bolts (2 places) + Anchor bolts (4 places) installed in shear area 117kN x 2

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

A1: Mechanical anchor A2: Anchor bolt C: Concrete structure F: Filler
h1: shear reinforcement groove h2: attachment groove N: nut S: shear crack
W: Washer E1: Epoxy resin
1: Multi-
1a: first carbon fiber board 1b: second carbon fiber board 1c: third carbon fiber board

Claims (7)

Identifying the shear reinforcement range to identify the location and extent for shear reinforcement by identifying the shear crack range of the concrete structure;
Shear crack directionality confirmation step to confirm the directionality of shear cracks in concrete structures;
Anchor location selecting step of selecting an anchor insertion position for shear reinforcement after confirming a reinforcing steel embedded in a concrete structure through nondestructive inspection at the shear reinforcement position and range determined in the step of confirming the shear reinforcement range;
Concrete structures for removing and cleaning foreign matter on the surface of concrete structures;
Attaching a multi-directional carbon fiberboard to the multi-directional carbon fiberboard after applying an adhesive to the surface of the multi-directional carbon fiberboard, and then attaching the multi-directional carbon fiberboard to reinforce the reinforced concrete surface;
A groove forming step of forming an attachment groove for attaching the shear reinforcement groove and the multi-directional carbon fiber plate for shear reinforcement at a position selected in the anchor positioning step;
An anchor inserting step of inserting a mechanical anchor into the shear reinforcement groove formed in the groove forming step and inserting an anchoring bolt into an attachment groove for attaching the multi-directional carbon fiber plate;
And a shear crack tightening step of tightening the shear cracked portion by joining the washer and the nut to the mechanical anchor and the anchoring bolt inserted in the anchor inserting step. The multi-directionally prepared carbon fiber board and the mechanical anchor Bending, Shear, and Seismic Performance Improvement of Reinforced Concrete Structures.
The carbon fiber sheet according to claim 1, wherein the carbon fiber sheet has a minimum tensile strength of 2200 MPa, a minimum elastic modulus of 160 GPa, and a length of 80 to 90% A second carbon fiber plate formed with a slope of +45 degrees with respect to the directionality of the first carbon fiber plate, and a third carbon fiber plate formed with a slope of -45 degrees with respect to the directionality of the first carbon fiber plate, Reinforced concrete reinforced concrete structure with reinforced carbon fiber boards and mechanical anchors, which is characterized in that the second and third carbon fiber boards are laminated on the upper and lower sides of the reinforced concrete structure.
[7] The method of claim 1, wherein in the step of confirming the direction of shear cracking, a portion of the shear cracks formed in the slanting line is formed with a multi-directionally formed carbon Bending, Shear, and Seismic Performance Improvement of Reinforced Concrete Structures Using Fiberboard and Mechanical Anchor.
The method of claim 1, wherein the mechanical anchor and the anchoring bolt in the anchor inserting step are formed of stainless steel, and one of the filler selected from mortar or epoxy is further formed when installing the mechanical anchor in the front end reinforcement groove Strengthening Method of Bending, Shear, and Seismic Performance Improvement of Concrete Structures Using Carbon Fiber Plates and Mechanical Anchors Prepared in Direction.
[2] The method of claim 1, wherein the washer in the step of tightening the shear crack uses a triangular washer for adhesion with the concrete structure when the direction of the shear crack is generated in a diagonal direction. Bending, Shear, and Seismic Performance Improvement of Reinforced Concrete Structures Using.
2. The method of claim 1, wherein tightening the nut to the mechanical anchor and the anchoring bolt in the shear crack tightening step is performed by using a torque wrench to perform a tightening operation at a constant torque, wherein a torque in a range in which the front ends of the mechanical anchor and the anchor bolt are not generated Reinforcing method of reinforced concrete structure with flexural, shear, and seismic performance using carbon fiber boards and mechanical anchors, which are characterized by tightening work.
The method of claim 1, further comprising the step of forming an epoxy resin around the anchor between the nut and the concrete structure in the step of shear cracking, wherein the bending, shearing, and shearing of the concrete structure using the carbon fiber plate and the mechanical anchor, And seismic performance enhancement method.

Images