JP2003293324A - Reinforcement method for concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent net bodies and coating resin for reinforcement from exfoliating off the surface of concrete structure, during the construction work of concrete structure. <P>SOLUTION: In this reinforcement method, grooves 11 in which lattice bars 20 for reinforcement are fitted are formed on the surface of a slab 1 of a concrete bridge. The lattice bars 20 are fitted into and fixed securely to the grooves 11, and a reinforcement layer is fixedly cut into the slab 1, even when an existing bridge which is installed warps, while the lattice bar 20 follows displacement of this bridge, and effects tensile stress, forming no gap between the reinforcement layer and the concrete, so that the lattice bar 20 and the existing bridge are unified. Therefore the surface exfoliation can be prevented for a long period of time. <P>COPYRIGHT: (C)2004,JPO

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 a concrete structure in which a reinforcing net is fixed to a concrete slab.

[0002]

2. Description of the Related Art A slab of a concrete bridge is directly and repeatedly applied with a dynamic load of a vehicle such as an automobile, and receives the most severe load and stress among the main members of a road bridge.
Therefore, especially on the lower surface of the floor slab, unidirectional cracks generate vertical and horizontal cracks, and further, these cracks grow and reticulate, which eventually causes the concrete to come off.

If such damage is left as it is, cracks further progress and corrosion of the reinforcing bars progresses, eventually leading to the destruction of the bridge. In order to avoid such a situation, the lower surface of the slab of a concrete bridge is repaired and reinforced.

As an example of this reinforcing method, Japanese Patent Laid-Open No. 8-3
There is a method described in Japanese Patent No. 38005. As shown in FIG. 5 (a), the reinforcing net bars 51a and 51b are formed in a grid shape and the grid point portions thereof are joined by welding in advance to produce the reinforcing net reinforcing bar 51. 51 is arranged along the lower surface of the floor slab 50 of the concrete bridge to reinforce it, as shown in FIG. Then, the reinforcing net reinforcing bar 51 is fixed by an anchor pin type fixing tool 52 driven into the floor slab 50, and after the fixing, three covering layers 53a, 53b, 53 are provided.
A reinforced structure covered by c is constructed.

The fixture 52 is a taper 52c that tapers the base end portion of a pin 52b connected to the head 52a. Then, as shown in (a) of the same figure, by tapping the tip of the pin 52b of the fixing tool 52 into the floor slab 50 at a position in contact with the grid point of the reinforcing net reinforcing bar 51, the taper 52c becomes the reinforcing net reinforcing bar 51. Hit the rebars that intersect each other. As a result, the force of pushing the lattice portion of the reinforcing net reinforcing bar 51 acts in the direction indicated by the arrow in (a) of the figure, and the pre-stress is applied to the entire reinforcing net reinforcing bar 51.

With such a reinforcing structure, the floor slab 50 is lined with the reinforcing net reinforcing bar 51 to reinforce the strength of the floor slab 50, and at the same time, the reinforcing net reinforcing bar 51 is prestressed. Therefore, even when the floor slab 50 is bent or displaced due to a load, the reinforcing net reinforcing bar 51 can follow these bending and displacement, so that the reinforcing net reinforcing bar 51
And the existing floor slab 50 are strengthened, and the reinforcing effect is maintained for a long period of time.

[0007]

In the above reinforcing structure, the coating layer 53a is fixed by directly adhering it to the lower surface of the floor slab 50, and the expansion coefficient and the expansion coefficient between the floor slab 50 and the coating layer 53a are fixed. This means that members having different properties of elasticity are bonded together. Therefore, when the floor slab 50 repeatedly bends and deforms due to a dynamic load, due to the difference in extensional deformation between the floor slab 50 and the covering layers 53a, 53b, 53c, these covering layers 53a, 53b, 53 at the bending portion.
There is a possibility that c may separate from the lower surface of the floor slab 50 and rise. In addition, in the damaged floor slab 50, a shearing force is generated on the adhesive surface between the floor slab 50 and the coating layer 53a due to the synergistic action of bending due to the wheel load of the passing vehicle and opening / closing of the crack opening, and the coating layers 53a, 53b. , 53c may be lifted.

Due to such a behavior, the coating layers 53a, 5a
When part of 3b, 53c is separated from the lower surface of the floor slab 50, the backing effect on the floor slab 50 is lost. And
Coating layers 53a, 53b, 53c that float from the floor slab 50
As the size of the floor becomes larger, the reinforcing effect on the floor slab 50 also decreases. Furthermore, the coating layer 53
Reinforcing mesh 5 due to lifting of a, 53b, 53c
The fixation of 1 becomes unstable and the reinforcing effect declines.

As described above, in the conventional method of reinforcing the floor slab 50, since the coating layers 53a, 53b and 53c are directly adhered to the lower surface of the floor slab 50, the concrete floor slab 50 and the coating layer 53a are formed. , 53b, 53c and the opening of the crack in the floor slab 50 may cause the coating layers 53a, 53b, 53c to separate from the lower surface of the floor slab 50 and reduce the reinforcing strength. There is. Further, since the entire floor slab is covered with the reinforcing net reinforcing bars 51 and other members, it is not possible to visually observe the progress of the floor slab 50 after the construction.

The above problem is not limited to the concrete slab floor slab, but can also be applied to other concrete structures such as building structures. Further, in the above-mentioned example, the net rebar made of iron is used as the reinforcing net, but there is a similar problem even when the material of the net is synthetic resin.

The problem to be solved in the present invention is that when the concrete structure is reinforced, the reinforcing net body is constrained so as not to move on the surface of the floor slab, so that the reinforcing net body is removed from the surface of the concrete structure. This is to prevent the coating resin from peeling off.

[0012]

SUMMARY OF THE INVENTION The present invention is a method for reinforcing a concrete structure, wherein a reinforcing net is fixed to the surface of the floor slab of the concrete structure to reinforce the floor slab. It is characterized in that a groove is formed in which the reinforcing net body is fitted, and the reinforcing net body is fitted and fixed in the groove.

By forming a groove into which the reinforcing net body is fitted in the surface portion of the floor slab and fitting and fixing the reinforcing net body into this groove, the reinforcing layer of the reinforcing net body bites into the floor slab. It will be the structure that exists. This reinforcing layer exerts a high tensile stress against the bending of the concrete structure itself, so that the deformation due to the bending can be prevented.

It is desirable that the reinforcing net body has a grid-like shape formed of square members. By forming the mesh body into a grid shape formed of square pieces, the production of the reinforcing mesh body and the construction of the groove are facilitated. Further, as the material of this net body, it is desirable to form it by laminating fiber reinforced plastics. Fiber reinforced plastics are resistant to corrosion such as rust, and because they have high tensile strength and are lightweight, they are easy to transport during construction. Furthermore, the grooves formed in the floor slab can exhibit the tensile strength of the reinforcing net most efficiently by being aligned with the directions of the main reinforcement and the back reinforcement of the concrete.

Here, after the reinforcing net is fitted in the groove of the floor slab, a wedge-shaped anchor is driven in the gap between the inner surface of the groove and the reinforcing net to restrain the reinforcing net and the resin is filled in the gap. Is preferably injected to fix the reinforcing net to the floor slab. By anchoring the anchor in the gap between the inner surface of the groove and the reinforcing mesh and fixing it with resin, the reinforcing mesh and the inner wall of the groove can be joined together without strictly controlling the accuracy of the fitting dimensions of the reinforcing mesh and the groove. It can be surface-contacted and firmly fixed.

Specific steps for carrying out the above-mentioned construction method include a step of forming a groove into which the reinforcing net body is fitted on the surface of the floor slab with a cutting tool, a step of cleaning the groove, and a reinforcing net in the groove. After fitting the body, the step of driving a wedge-shaped anchor into the gap between the inner surface of the groove and the reinforcing net to restrain the reinforcing net, and the step of covering the floor slab surface including the groove with resin, A step of restraining the net for the floor and fixing the reinforcing net to the floor slab by injecting the resin into the gap of the groove while the surface of the floor slab is covered with the resin, and a step of removing the resin covering the surface of the floor slab Will be included.

The step of forming the groove and the step of restraining the reinforcing net body after the reinforcing net body is fitted and fitted into the groove can form the reinforcing layer that has bite into the concrete surface. In addition, by the step of cleaning the groove and the step of injecting a resin into the gap between the inner surface of the groove and the reinforcing netting to fix the reinforcing netting to the floor slab, the inside of the cracks generated in the floor slab A resin for fixing the mesh body can be permeated into the resin to suppress the development of cracks. Further, by finally removing the resin covering the surface of the floor slab, the surface of the floor slab made of concrete is exposed, so that the change in the surface condition of the floor slab after reinforcement can be continuously monitored.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. 1 (a) is an overall view of a concrete bridge to which the present invention is applied, in which 1 is a floor slab made of reinforced concrete, ground coverings 2 are formed at both ends of the floor slab 1, and the bottom surface of the floor slab 1 is Three columns of bridge girders 3 are provided.
A reinforcing coating layer 9 is formed on the entire lower surface of the floor slab 1.

FIG. 1 (b) is an enlarged sectional view of the portion A in FIG. 1 (a), and FIG. 1 (c) is a bottom view of the reinforcing coating layer 9 in FIG. 1 (b). Inside the floor slab 1, an upper reinforcing bar 4a and a lower reinforcing bar 4b are arranged. Lower surface 1s of this floor slab 1
, A grid-shaped groove 11 is formed in the same direction as the reinforcing bars 4a and 4b and in a direction perpendicular to the reinforcing bar 4a, 4b, and a fiber-reinforced plastic (FRP) grid reinforcing bar 20 is fitted into the groove 11 (see FIG. 2). (See (b)). This lattice streak 20 has a groove 1
It is fixed in the groove 11 by filling the inside of the epoxy resin 30 and hardening it.

In the above structure, the lattice reinforcement 20 is the floor slab 1
It is fixed in a state of being fitted in the groove 11 formed in the lower surface 1s of the. Moreover, since the resin 30 made of an epoxy resin is interposed between the lattice streak 20 and the groove 11, even when the floor slab 1 is repeatedly bent and deformed by a dynamic load, the strain force due to the deformation of the floor slab 1 is increased. Is transmitted to the lattice streak 20 via the resin 30 in the groove 11.

That is, since the lattice streaks 20 are sealed in the grooves 11 of the floor slab 1, when the floor slab 1 is flexibly deformed, the lattice streaks 20 of the floor slab 1 are flexibly deformed. Groove 1
1 has a function of keeping the distance D between the side walls constant. As a result, even if the floor slab 1 is displaced due to bending due to a load, the displacement is absorbed within the elastic range of the lattice reinforcement 20 so that the entire floor surface of the floor slab 1 has a high tensile stress. . Further, the lattice streak 20 does not lift up from the groove 11 of the floor slab 1.

Next, with reference to FIGS. 2 and 3, the procedure for applying the coating layer 9 will be described. In FIG. 2 (a),
Reference numeral 1 is a floor slab made of reinforced concrete, and 1s is a lower surface of the floor slab 1. A crack 1c is present on this lower surface 1s. In order to reinforce the floor slab 1, as shown in FIG. 2 (b), on the lower surface 1s surface of the floor slab 1, in the directions parallel to the main and back muscles arranged in the floor slab 1 by the concrete cutter. The grid-like grooves 11 having a width of 15 mm and a depth of 15 mm are drilled at a pitch of 100 mm. After this 10
The entire surface is washed with a high-pressure water rinsing kettle with jet water of -20 MPa. By this cleaning, the crack 1c on the lower surface 1s
Remove any debris inside.

Next, a FRP lattice streak 20 formed of a square member having a width of 10 mm and a height of 10 mm and having a lattice of the same pitch as the groove 11 is fitted into the groove 11 of the lower surface 1s. Here, when arranging the two lattice reinforcements 20 at the joint portion of the lattice reinforcement 20, a deep groove 11a is formed as shown in FIG. 2C, and the joint reinforcement 20a is fitted into the deep groove 11a. Put in. As a result, the connection is made so as to continuously exert strength, and the entire reinforcing surface of the floor slab 1 is covered, and a structure similar to that of the integral FRP lattice reinforcement 20 having continuous tensile strength can be obtained. it can.

Next, as shown in FIG. 3 (a), a wedge anchor 25 is fitted in the gap between the side wall inside the groove 11 of the floor slab 1 and the lattice reinforcement 20 made of FRP to fix the lattice reinforcement 20. . As shown in FIG. 3C, the wedge anchor 25 has a circular bottom surface, an elliptical top surface, and a hollow interior. The hollow portion 25a serves as an injection port when the low-viscosity resin 30 is injected, as will be described later.

Next, as shown in FIG. 4A, the clay-like resin 21 is covered so as to cover the lattice streak 20 in all the grooves except the portion where the wedge anchor 25 is fitted. The clay-like resin 21 is for the purpose of preventing the low-viscosity resin 30 from leaking when the resin is injected, so that it can be applied with resin mortar. Further, as shown in FIG. 4B, the release resin 22 is sprayed on the clay-like resin 21 to prevent the low-viscosity resin 30 from leaking from the clay-like resin 21. The method for applying the peelable resin 22 may be, of course, trowel coating, but spraying is suitable in terms of efficiency particularly when upward coating is applied to the ceiling.

After these steps, as shown in FIG. 3B, an injector is connected to the inside of the wedge anchor 25, and the low-viscosity resin 3 is placed inside the groove 11 sealed with the clay-like resin 21.
Inject 0. Since the low-viscosity resin 30 has a low viscosity, it fills the space inside the groove 11 and permeates into the space inside the crack 1c of the floor slab 1.

By injecting the low-viscosity resin 30 from the center of the repair surface, the anchors 25 other than the injection site function as air vents. Anchor 2 with low viscosity resin 30 for venting air
After confirming that it reached 5, the first injection anchor 25 is sealed with a rubber stopper etc. to prevent backflow of the low-viscosity resin 30 and then injected from the air-releasing anchor 25 to minimize air inclusion. The low-viscosity resin 30 can be injected into all the grooves while limiting the amount. As the low-viscosity resin 30, it is desirable to use an epoxy resin or the like from the viewpoint of easy construction.

The low-viscosity resin 30 that has penetrated into the crack 1c penetrates toward the tip of the crack 1c inside the concrete without leaking from the crack 1c that has reached the surface 1s by the peelable resin 22. After the permeated low-viscosity resin 30 is cured, permeation of water into the existing cracks 1c is prevented. As a result, it is possible to prevent the reinforcing bar itself from expanding due to the permeated water inside the concrete to corrode due to the permeated water, thereby causing a new crack. Moreover, since the existing concrete surface is exposed by injecting the low-viscosity resin 30 and curing it and then peeling off the peelable resin 22, it is possible to visually observe the progress of the crack 1c after the construction.

Further, since the hardened low-viscosity resin 30 has penetrated into the existing cracks, even if tensile due to bending occurs, the tensile force of the cracks is suppressed by the elastic force of the low-viscosity resin 30 itself. By suppressing the displacement itself due to the bending by suppressing the pulling, the progress of the crack of the floor slab 1 due to the repeated displacement can be delayed.

Since this method does not drive the anchor into the concrete, it does not generate new cracks and does not put a burden on the existing concrete.

The method of this embodiment is not limited to the repair of a damaged concrete structure. For example, the service life is 2
Needless to say, it can be applied to a bridge designed for 0 years to have a useful life of 25 years. Further, not only the floor slab but also the reinforcement of the lower surface of the girder can be similarly applied. In particular, it is most effective for floor slabs and girders that constantly bend due to passing traffic even during construction.

[0032]

According to the present invention, the following effects can be obtained. (1) Forming a groove into which the reinforcing net is fitted in the surface portion of the floor slab of the concrete structure, and inserting the reinforcing net into the groove to fix the groove, so that the reinforcing layer is in the state of being cut into the floor slab. , Even when the installed existing bridge is bent, the reinforcing net body exerts tensile stress while following the displacement of this bridge, so there is no gap between the reinforcing layer and concrete, The net can be integrated with the existing bridge, and it will be a reinforcing method that can maintain the surface separation prevention for a long period of time.

(2) After the reinforcing net is fitted into the groove of the floor slab, a wedge-shaped anchor is driven in the gap between the inner surface of the groove and the reinforcing net to restrain the reinforcing net and to fit in the gap. By injecting a resin and fixing the reinforcing net member to the floor slab, a reinforcing layer that efficiently exhibits tensile strength against concrete regardless of the accuracy of the fitting size of the reinforcing net member and the groove is obtained. Further, by interposing the resin between the floor slab and the reinforcing net, no shearing force is generated on the reinforcing netting and no shearing force breakage occurs. Furthermore, this resin also functions as a repair material for cracks in the floor slab.

(3) A step of forming a groove, a step of cleaning the groove, and a step of fitting a reinforcing net body into the groove, and then,
Steps of driving the anchors and restraining them, covering them with resin, restraining the reinforcing netting and injecting resin to fix the reinforcing netting to the floor slab, and removing the resin covering the floor slab surface. By including the step of performing, it is possible to efficiently fix the reinforcing netting and prevent peeling.

[Brief description of drawings]

1A is an overall view of a concrete bridge to which the present invention is applied, FIG. 1B is an enlarged cross-sectional view of part A of FIG. 1A, and FIG.
FIG. 4B is a bottom view of the reinforcing coating layer of (b).

FIG. 2 is an explanatory diagram showing a construction procedure of the present invention.

FIG. 3 is an explanatory diagram showing a construction procedure of the present invention.

FIG. 4 is an explanatory diagram showing a construction procedure of the present invention.

FIG. 5 is a schematic view showing a conventional reinforcing structure.

[Explanation of symbols]

1 floor slab 1s bottom surface 1c crack 2 ground cover 3 bridge girders 4a Upper rebar 4b Lower rebar 9 Reinforcing coating layer 11 grooves 20 Lattice muscle 21 Clay-like resin 22 Peelable resin 25 anchor 30 Low viscosity resin

Claims (3)

[Claims] 1. A method of reinforcing a concrete structure for fixing a reinforcing net body to the surface of a concrete structure, wherein a groove for fitting the reinforcing net body is formed on the surface of the concrete structure, and the groove is formed in the groove. A reinforcing method for a concrete structure, characterized by fitting and fixing a reinforcing net body. 2. After the reinforcing net body is fitted in the groove, a wedge-shaped anchor is driven into the gap between the reinforcing net body and the inner surface of the groove to restrain the reinforcing net body and the gap. The method for reinforcing a concrete structure according to claim 1, wherein the reinforcing net body is fixed to the floor slab by injecting a resin into the resin. 3. A step of forming a groove into which a reinforcing net body is fitted on a surface portion of a concrete structure with a cutting tool, a step of cleaning the groove, and a step of fitting the reinforcing net body into the groove after fitting. , A step of driving a wedge-shaped anchor into the gap between the inner surface of the groove and the reinforcing netting to restrain the reinforcing netting, a step of covering the floor slab surface including the groove with resin, and restraining the reinforcing netting. And a step of injecting a resin into the gap of the groove to fix the reinforcing net to the floor slab with the floor slab surface covered with the resin, and removing the resin covering the floor slab surface. Reinforcement method for concrete structures.