JP3751258B2 - Reinforcement method for concrete structures - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
The concrete bridge floor slab is directly and repeatedly subjected to the dynamic load of a vehicle such as an automobile, and is subjected to the most severe load and stress among the main members of a road bridge. For this reason, especially in the lower surface of the floor slab, vertical and horizontal cracks are generated from cracks in one direction, and further, these cracks grow and become reticulated, and eventually cause peeling of concrete.
[0003]
If such damage is left unattended, cracks will progress further and progress to corrosion of the reinforcing bars, eventually leading to the destruction of the bridge. In order to avoid such a situation, the lower surface of the floor slab of a concrete bridge is repaired and reinforced.
[0004]
As an example of this reinforcing method, there is a method described in JP-A-8-338005. This is because, as shown in FIG. 5 (a), reinforcing reinforcing bars 51a and 51b are formed in a lattice shape and reinforcing mesh reinforcing bars 51 in which the lattice points are joined together by welding are manufactured in advance. As shown in (b) of the figure, 51 is reinforced by being arranged along the lower surface of the floor slab 50 of the concrete bridge. Then, the reinforcing mesh reinforcing bar 51 is fixed by an anchor pin type fixing tool 52 driven into the floor slab 50, and after this fixing, a reinforcing structure covered with three layers of covering layers 53a, 53b, 53c is applied.
[0005]
The fixing tool 52 has a taper 52c that tapers the proximal end portion of the pin 52b connected to the head 52a. And as shown to (a) of the figure, the taper 52c is made into the reinforcement net | network reinforcement 51 by driving the front-end | tip of the pin 52b of the fixing tool 52 into the floor slab 50 in the position which touches the lattice point of the reinforcement | strengthening net reinforcement 51. Hit the bars that cross each other. Thereby, the force which pushes the grid | lattice part of the reinforcement netting reinforcement 51 acts in the direction shown by the arrow in (a) of the figure, and it will be in the state which loaded the prestress to the whole reinforcement reinforcement.
[0006]
With such a reinforcement structure, the floor slab 50 is lined by the reinforcing mesh reinforcement 51 to reinforce the strength of the floor slab 50, and at the same time, the reinforcement mesh reinforcement 51 is prestressed. Even when the floor slab 50 bends or displaces due to a load, the reinforcing mesh reinforcing bar 51 can follow these deflections and displacements, so that the integration of the reinforcing mesh reinforcing bar 51 and the existing floor slab 50 is strengthened. The reinforcing effect is maintained over a long period of time.
[0007]
[Problems to be solved by the invention]
In the above reinforcing structure, the covering layer 53a is fixed by directly adhering to the lower surface of the floor slab 50, and members having properties having different expansion coefficients and elastic coefficients between the floor slab 50 and the covering layer 53a. Will be adhered. For this reason, when the floor slab 50 is repeatedly bent and deformed by a dynamic load, the covering layers 53a, 53b, and 53c are deformed in the bent portion due to the difference in elongation deformation between the floor slab 50 and the covering layers 53a, 53b, and 53c. There is a possibility that the slab is lifted away from the lower surface of the floor slab 50. Further, in the damaged floor slab 50, a shearing force is generated on the bonding surface of the floor slab 50 and the covering layer 53a due to a synergistic action of the bending due to the wheel load of the passing vehicle and the opening and closing of the crack opening, and the covering layers 53a and 53b. , 53c may be lifted.
[0008]
If a part of the coating layers 53a, 53b, 53c is separated from the lower surface of the floor slab 50 by such behavior, the backing effect on the floor slab 50 is lost. And the reinforcement effect with respect to the floor slab 50 will also decline as the area of the coating layers 53a, 53b, 53c which floats from the floor slab 50 becomes large. Furthermore, the reinforcement of the reinforcing net 51 becomes unstable due to the rising of the covering layers 53a, 53b, 53c, and the reinforcing effect is reduced.
[0009]
As described above, in the conventional reinforcing method of the floor slab 50, since the covering layers 53a, 53b, and 53c are directly bonded to the lower surface of the floor slab 50, the concrete floor slab 50 and the covering layers 53a, 53b, Due to the difference in material with respect to 53c and the opening and closing of the crack opening of the floor slab 50, the covering layers 53a, 53b, 53c may be separated from the lower surface of the floor slab 50 and cause a reduction in reinforcement strength. Further, since the entire floor slab is covered with the reinforcing mesh bars 51 and other members, the progress of the floor slab 50 after construction cannot be visually observed.
[0010]
The above problem is not limited to the concrete slab floor slab, but can also be said for other concrete structures such as buildings. In the above example, an iron net reinforcing bar is used as the reinforcing net, but there is a similar problem even when the net is made of synthetic resin.
[0011]
The problem to be solved in the present invention is that when reinforcing a concrete structure, the reinforcing mesh body is restrained from moving on the surface of the floor slab so that the reinforcing mesh body and the coating resin are separated from the surface of the concrete structure. It is to prevent peeling.
[0012]
[Means for Solving the Problems]
The present invention relates to a concrete structure reinforcing method for reinforcing a floor slab by fixing a reinforcing mesh to the surface of a floor slab of a concrete structure, and a groove for fitting the reinforcing mesh into the surface of the floor slab And a reinforcing net is fitted into the groove and fixed.
[0013]
A groove for fitting the reinforcing mesh is formed in the surface portion of the floor slab, and the reinforcing mesh is fitted into the groove and fixed, so that a reinforcing layer by the reinforcing mesh is bitten into the floor slab. It becomes composition. This reinforcing layer can prevent deformation due to bending by exerting a high tensile stress against the bending of the concrete structure itself.
[0014]
It is desirable that the reinforcing net has a lattice shape formed of square bars. By making the mesh body into a grid-like shape formed of square bars, it becomes easy to manufacture the reinforcing mesh body and construct the grooves. Further, it is desirable to form the net body by lamination of fiber reinforced plastic. Fiber reinforced plastics are less susceptible to corrosion such as rust, and are lightweight while having high tensile strength, so they can be easily transported during construction. Further, the grooves formed in the floor slab can be most efficiently exerted by the tensile strength of the reinforcing net by matching the direction of the main and back bars of the concrete.
[0015]
Here, after the reinforcing mesh is fitted in the groove of the floor slab, a wedge-shaped anchor is driven into the gap between the inner surface of the groove and the reinforcing mesh to restrain the reinforcing mesh and inject resin into the gap. It is desirable to fix the reinforcing net to the floor slab. By anchoring the anchor into the gap between the inner surface of the groove and the reinforcing net and fixing it with resin, the reinforcing net and the inner wall of the groove can be connected without strictly controlling the accuracy of the fitting size of the reinforcing net and the groove. It can be fixed firmly by surface contact.
[0016]
As specific steps for carrying out the above method, a cutting tool is used to form a groove for fitting the reinforcing mesh on the surface of the floor slab, a step for cleaning the groove, and a reinforcing mesh is fitted 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 net body to restrain the reinforcing net body, a step of covering the floor slab surface including the groove with a resin, and a reinforcing net body And a step of injecting resin into the gap of the groove with the floor slab surface covered with resin and fixing the reinforcing net to the floor slab, and a step of removing the resin covering the floor slab surface It becomes.
[0017]
By the step of forming a groove and the step of constraining the reinforcing net after fitting and fitting the reinforcing net into the groove, a reinforcing layer biting into the concrete surface can be formed. Further, the interior of the crack generated in the floor slab is obtained by washing the groove and injecting resin into the gap between the inner surface of the groove and the reinforcing mesh to fix the reinforcing mesh to the floor slab. It is possible to suppress the progress of cracks by infiltrating the resin for fixing the mesh body. Moreover, since the surface of the concrete floor slab is exposed by removing the resin covering the surface of the floor slab at the end, the change in the surface state of the floor slab after reinforcement can be continuously monitored.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 (a) is an overall view of a concrete bridge to which the present invention is applied. 1 is a floor slab made of reinforced concrete, and a ground cover 2 is formed at both ends of the floor slab 1, and Three rows of bridge girders 3 are provided. A reinforcing covering layer 9 is formed on the entire lower surface of the floor slab 1.
[0019]
1B is an enlarged cross-sectional view of a portion A in FIG. 1A, and FIG. 1C is a bottom view of the reinforcing coating layer 9 in FIG. Inside the floor slab 1, an upper reinforcing bar 4a and a lower reinforcing bar 4b are arranged. A lattice-like groove 11 is formed on the lower surface 1s of the floor slab 1 in the same direction as the reinforcing bars 4a and 4b and in a direction perpendicular to the reinforcing bars 4a and 4b, and a lattice reinforcement 20 made of fiber reinforced plastic (FRP) is fitted inside the groove 11. (See FIG. 2 (b)). The lattice bars 20 are fixed in the grooves 11 by filling the grooves 11 with the epoxy resin 30 and curing them.
[0020]
In the above configuration, the lattice bars 20 are fixed in a state of being fitted in the grooves 11 formed on the lower surface 1 s of the floor slab 1. Moreover, since the resin 30 made of epoxy resin is interposed between the lattice bars 20 and the grooves 11, even when the floor slab 1 is repeatedly bent and deformed by a dynamic load, the distortion force due to the deformation of the floor slab 1 Is transmitted to the lattice line 20 through the resin 30 in the groove 11.
[0021]
That is, since the lattice bars 20 are sealed in the grooves 11 of the floor slab 1, when the floor slab 1 is bent and deformed, the lattice lines 20 are formed in the grooves 11 of the floor slab 1 against the deformation of the floor slab 1. The distance D between the side walls is kept constant. Thereby, even when the displacement of the floor slab 1 due to bending occurs due to the load, the entire surface direction of the floor slab 1 is provided with a high tensile stress by absorbing the displacement within the elastic range of the lattice reinforcement 20. . Further, the lattice line 20 does not float from the groove 11 of the floor slab 1.
[0022]
Next, with reference to FIG. 2 and FIG. 3, the construction procedure of the coating layer 9 will be described.
In FIG. 2A, 1 is a floor slab made of reinforced concrete, and 1 s is a lower surface of the floor slab 1. The lower surface 1s has a crack 1c. In order to reinforce the floor slab 1, as shown in FIG. 2 (b), on the surface of the lower surface 1 s of the floor slab 1 in a direction parallel to the main and back bars arranged on the floor slab 1 by a concrete cutter. A grid-like groove 11 having a width of about 15 mm and a depth of about 15 mm is drilled at a pitch of 100 mm. Thereafter, the entire surface is washed by high pressure water washing with 10 to 20 MPa jet water. By this cleaning, dust and the like in the crack 1c on the lower surface 1s are removed.
[0023]
Next, an FRP lattice 20 formed of a square member having a width of 10 mm and a height of 10 mm and having a lattice having the same pitch as the grooves 11 is fitted into the grooves 11 on the lower surface 1 s. Here, when the two lattice bars 20 are arranged at the joint portion of the lattice line 20, a deep groove 11a is formed as shown in FIG. 2 (c), and the lattice line 20a for fitting is fitted into the deep groove 11a. Include. Thereby, it becomes the structure connected so that intensity | strength may be exhibited continuously, and it is set as the structure similar to the integral FRP grid | lattice reinforcement 20 with the tensile strength which covers the whole reinforcement surface of the floor slab 1 and has no cut. it can.
[0024]
Next, as shown in FIG. 3A, a wedge anchor 25 is fitted into a 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. As will be described later, the hollow portion 25a serves as an inlet when the low-viscosity resin 30 is injected.
[0025]
Next, as shown in FIG. 4A, the clay-like resin 21 is placed so as to cover the lattice line 20 in all the grooves other than the portion where the wedge anchor 25 is inserted. Since the clay-like resin 21 is intended to prevent the low-viscosity resin 30 from leaking when the resin is injected, it can be applied with resin mortar. Further, as shown in FIG. 4B, the release resin 22 is sprayed from above the clay-like resin 21 to prevent the low-viscosity resin 30 from leaking from the clay-like resin 21. Of course, the application method of the peelable resin 22 is possible by applying a trowel. However, in particular, when the coating is applied upward on the ceiling, the application by spraying is suitable in terms of efficiency.
[0026]
After these steps, an injector is connected to the inside of the wedge anchor 25 as shown in FIG. 3B, and the low viscosity resin 30 is injected into the groove 11 sealed with the clay-like resin 21. . Since this low-viscosity resin 30 has a low viscosity, it fills the space in the groove 11 and penetrates into the space inside the crack 1 c of the floor slab 1.
[0027]
Further, by injecting the low-viscosity resin 30 from the center of the repair surface, the anchors 25 other than the injection location function as air vents. After confirming that the low-viscosity resin 30 has reached the air vent anchor 25, the first injection anchor 25 is sealed with a rubber stopper, etc., and the back flow of the low-viscosity resin 30 is prevented and then injected from the air vent anchor 25. Thus, the low-viscosity resin 30 can be injected into all the grooves while minimizing air contamination. As this low-viscosity resin 30, it is desirable to use an epoxy resin or the like because it is easy to construct.
[0028]
The low-viscosity resin 30 that has penetrated into the crack 1c permeates toward the tip of the crack 1c inside the concrete without leaking from the crack 1c that has reached the surface 1s by the release resin 22. After the penetrated low viscosity resin 30 is cured, the penetration of moisture into the existing crack 1c is prevented. Thereby, it is prevented that the volume of the reinforcing bar itself is expanded due to corrosion caused by the moisture that has penetrated the reinforcing bar inside the concrete and a new crack is generated. Moreover, since the existing concrete surface is exposed by peeling the release resin 22 after injecting and curing the low viscosity resin 30, it is also possible to visually observe the progress of the crack 1c after the construction.
[0029]
Further, since the cured low-viscosity resin 30 penetrates into the existing cracks, even if a tensile due to bending occurs, the tensile of the crack 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 pull, the progress of the crack of the floor slab 1 due to the repetition of the displacement can be delayed.
[0030]
In addition, since this method does not drive anchors into concrete, it does not generate new cracks and does not place a burden on existing concrete.
[0031]
The method of the present embodiment is not limited to repairing a damaged concrete structure. For example, a bridge designed for a service life of 20 years can be applied to a service life of 25 years. . Further, the present invention can be similarly applied not only to the floor slab but also to the reinforcement of the underside of the girder. In particular, it is most effective for floor slabs and girders that are repeatedly bent due to passing traffic even during construction.
[0032]
【The invention's effect】
The following effects can be achieved by the present invention.
(1) A groove for fitting a reinforcing mesh body is formed on the surface portion of the floor slab of a concrete structure, and the reinforcing layer is cut into the floor slab by fitting and fixing the reinforcing mesh body in this groove. Even when the installed existing bridge is bent, the reinforcing mesh exerts tensile stress while following the displacement of the bridge, so there is no gap between the reinforcing layer and the concrete. The net body and the existing bridge can be integrated, and the reinforcement method can maintain the prevention of surface peeling for a long time.
[0033]
(2) After fitting a reinforcing mesh into the groove of the floor slab, a wedge-shaped anchor is driven into the gap between the inner surface of the groove and the reinforcing mesh to restrain the reinforcing mesh and inject resin into the gap By fixing the reinforcing net to the floor slab, the reinforcing layer efficiently exhibits the tensile strength against the concrete irrespective of the accuracy of the fitting size of the reinforcing net and the groove. Further, by interposing the resin between the floor slab and the reinforcing net, no shearing force is generated on the reinforcing net and no shear force breakage occurs. Furthermore, this resin also functions as a repair material for cracks in the floor slab.
[0034]
(3) a step of forming a groove, a step of cleaning the groove, a step of fitting and inserting a reinforcing net into the groove, and then anchoring the anchor, a step of covering with a resin, and a reinforcing net Constraining the body, injecting resin to fix the reinforcing mesh to the floor slab, and removing the resin covering the floor slab surface to fix the reinforcing mesh and prevent peeling Can be performed efficiently.
[Brief description of the drawings]
1A is an overall view of a concrete bridge to which the present invention is applied, FIG. 1B is an enlarged sectional view of a portion A of FIG. 1A, and FIG. 1C is a bottom view of a reinforcing covering layer of FIG. is there.
FIG. 2 is an explanatory view showing a construction procedure of the present invention.
FIG. 3 is an explanatory view showing a construction procedure of the present invention.
FIG. 4 is an explanatory view showing a construction procedure of the present invention.
FIG. 5 is a schematic view showing a conventional reinforcing structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Floor slab 1s Lower surface 1c Crack 2 Ground cover 3 Bridge girder 4a Upper rebar 4b Lower rebar 9 Reinforcement coating layer 11 Groove 20 Lattice rebar 21 Clay-like resin 22 Peeling resin 25 Anchor 30 Low viscosity resin

Claims (2)

A concrete structure reinforcing method for reinforcing a floor slab by fixing a reinforcing mesh on the surface of a floor slab of a concrete structure, wherein a groove for fitting the reinforcing mesh is formed on the surface of the floor slab. After inserting the reinforcing net into the groove, a wedge-shaped anchor is driven into the gap between the inner surface of the groove and the reinforcing net to restrain the reinforcing net and inject resin into the gap. A reinforcing method for a concrete structure, wherein the reinforcing net is fixed to the floor slab . Forming a groove for fitting a reinforcing net body surface portion of the slab of the concrete structure by a cutting tool, a step of washing the grooves, after forme because fitting the reinforcing net assembly into the groove, A step of driving a wedge-shaped anchor into a gap between the inner surface of the groove and the reinforcing net body to restrain the reinforcing net body, a step of covering the floor slab surface including the groove with a resin, and the reinforcing net Restraining the body, injecting resin into the gaps in the groove with the floor slab surface covered with resin, and fixing the reinforcing net to the floor slab, and removing the resin covering the floor slab surface Reinforcement method of concrete structure including the process to do.

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