JP2011241635A - Concrete piece guard net - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete piece guard net, which is easy in construction work, allowing the working time to be shortened, preventing large to small pieces of concrete from falling down.SOLUTION: A concrete piece guard net comprises a mesh sheet for receiving pieces of flaking concrete and shape retaining bands for providing the mesh sheet with shape retentivity, the mesh sheet being formed into a net shape by reinforcements with vinylon core wires, the mesh of a body part having an aperture of 5 to 20 mm, the shape retaining bands being attached on the surface of the mesh sheet along at least one direction. The shape retaining bands are made from glass fiber impregnated with an alkali resistant thermosetting synthetic resin.

Description

  The present invention relates to a concrete piece protection net. More particularly, the present invention relates to a protective net for preventing the fall of concrete strips caused by deterioration from concrete structures such as tunnels, buildings, and bridges.

There exists patent document 1 as a conventional peeling prevention technique of a concrete piece.
This prior art uses a wide-surface lattice body that can support a large area with FRP lattice lines, and this will be described with reference to FIG.
The FRP lattice reinforcement 100 is configured by a wide-surface lattice body from vertical reinforcement reinforcements 101 and transverse reinforcement reinforcements 102 which are arranged in a lattice pattern orthogonal to each other. Each of the reinforcing bars 101 and 102 is formed by laminating and curing a plurality of impregnated matrix resins such as vinyl ester resins mainly using glass fibers, carbon fibers, and aramid fibers as core materials. . The FRP lattice bars 100 usually have a reinforcing bar width (w) of 3 to 10 mm, a thickness of 1 to 5 mm, and an inter-lattice distance (W1) of 30 to 150 mm.

  In the above-described conventional example, the wide-faced lattice body composed of the FRP lattice lines 100 is fixed to the concrete surface using the anchor bolts 101 to prevent the concrete pieces from peeling off. That is, after the FRP lattice 100 is overlapped on the concrete surface, the washer 102 having an outer shape corresponding to at least one part of the FRP lattice 100 and having a recess in the center is recessed in the concrete surface side. So that it fits to the outer surface of the FRP lattice line 100, and then penetrates the through hole formed in the recess of the washer 102 and drives the anchor bolt 101 into the concrete surface, and the FRP lattice line 100 is passed through the washer 102. Secure to concrete surface.

  Patent Document 1 also discloses a method in which fine meshes are overlapped on the wide-faced lattice body formed of the FRP lattice lines 100 described above. In this case, a polyester mesh 103 having a fine mesh is placed under the FRP lattice 100 having a large mesh, that is, disposed between the FRP lattice 100 and the concrete structure, and the expandable anchor bolt 101 and A washer 102 is used to attach to the concrete structure. The size of the mesh of the mesh 103 is smaller than that of the FRP lattice 100, and the mesh 3 of the mesh 3 is 1 for the FRP lattice 100 having a side of a square of 30 to 150 mm. Those with sides of 1 to 25 mm are used.

However, the prior art has the following problems.
(1) When the construction area is large, the wide grids made of FRP grids are spliced together. However, since the reinforcing bars 101 and 102 intersect, a plurality of wide grids cannot be overlapped, and there are gaps at the joints. There is a drawback that it is easy to occur or is easily damaged because of low support strength.
(2) Since the FRP lattice line 100 has a relatively large lattice interval, it has not been possible to prevent the fall of small concrete pieces. Even if a polyester net 103 is used, it has a low strength, so it is easily torn and is not often used.
(3) Since the vertical and horizontal reinforcing bars 101 and 102 are visually conspicuous, the scenery after construction was bad.

JP 2006-9266 A

  In view of the above circumstances, the present invention provides a concrete piece protection net that is effective for a large area wall surface, is easy in construction work, requires a short work time, and can prevent falling from a large concrete piece to a small concrete piece. For the purpose.

The concrete piece protection net according to the first invention comprises a mesh sheet for receiving a stripped piece of concrete, and a shape retention band for imparting shape retention to the mesh sheet, wherein the mesh sheet is a reinforcing bar whose core is a vinylon fiber The mesh of the main body has a mesh opening of 5 to 20 mm, and the shape retention band is attached in at least one direction on the surface of the mesh sheet. It is characterized by.
The concrete piece protection net according to a second aspect of the present invention is characterized in that, in the first aspect, the shape retention bands are attached in a direction crossing each other on the surface of the mesh sheet.
The concrete piece protection net of the third invention is characterized in that, in the first invention, the shape retention band is obtained by impregnating a glass fiber with a thermosetting synthetic resin having alkali resistance.
According to a fourth aspect of the present invention, there is provided the concrete piece protection net according to the first aspect, wherein the reinforcing bars are formed with a weather-resistant synthetic resin film on the outer periphery of the core wire.
The concrete piece protection net of the fifth invention is characterized in that, in the third invention, the synthetic resin coating is a PVC coating.

According to the first invention, the mesh sheet is made of vinylon fiber as the core wire, so that it has flexibility, but the shape retention band does not naturally bend or bend by the shape retention band, so the construction surface is curved. It can be easily mounted even on wall surfaces that are turned or face down. Moreover, since the sheet | seat is formed with the vinylon fiber, since the sheet | seat itself is thin and it is possible to overlap | superpose two sheets | sheets by side edges, it can construct also on a wide area wall surface without a gap. And since the main part of the sheet has a large mesh, the weight is light, but even small concrete pieces are not allowed to pass through, and the strength is high, so it is possible to effectively prevent peeling of the concrete pieces regardless of the size of the concrete pieces. .
According to the second aspect of the invention, since the shape-retaining band is oriented in the intersecting direction, the shape-retaining property of the protective net is exhibited in all directions. For this reason, since the drooping of the protective net is reduced even in a place where the construction surface is curved or downward, the labor for temporarily holding the protective net during work is unnecessary, and the workability is improved.
According to the third invention, since the shape retention band impregnates the glass fiber with the synthetic resin having alkali resistance, the alkali resistance is high, and it is not deteriorated by the alkali component in the concrete after construction. Moreover, since it is impregnated with the thermosetting resin, it is difficult to separate even when it is integrated with the mesh sheet by thermal pressing and applied to the curved portion.
According to the fourth invention, the outer peripheral surface of the reinforcing bar is coated with a weather-resistant synthetic resin, so that it does not deteriorate even after long-term use. Therefore, the concrete piece can be prevented from falling for a long time.
According to the fifth invention, since the PVC film is formed on the outer peripheral surface of the reinforcing bar, not only the weather resistance but also the shape retainability is good, so that the workability is improved and there is also flame retardancy. It is hard to deteriorate by.

It is a perspective view of a concrete piece protection net concerning one embodiment of the present invention. It is a fragmentary top view of the mesh sheet | seat part in a concrete piece protection net. It is a partial back view of a mesh sheet part in a concrete piece protection net. FIG. 4A is an explanatory diagram of an anchor bolt, and FIG. 4B is a sectional view of the anchor bolt in a driven state. It is explanatory drawing of the construction method of the concrete piece protection net which concerns on this invention. It is explanatory drawing of the state which constructed the concrete piece protection net concerning the embodiment in the tunnel. It is explanatory drawing of the conventional concrete peeling prevention technique.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a concrete piece protection net A, which is composed of a mesh sheet 10 and a shape retaining band 6. The mesh sheet 10 includes the main body 1 and the edge 2, but the edge 2 may not be provided and only the main body 1 may be provided.
The shape retention band 6 gives the mesh sheet 10 rigidity capable of retaining its own shape. In this specification, the rigidity capable of shape retention is referred to as shape retention. In other words, it is not preferable to give more rigidity than necessary to maintain the shape because it becomes unnecessarily hard and lowers workability.

The shape retention band 6 may be provided in one direction with respect to the mesh sheet 10, but may be provided in two directions orthogonal to each other.
When the shape retention band 6 is provided in one direction, the rigidity increases in the extending direction of the shape retention band 6 and exhibits shape retention.
When the shape holding band 6 is provided in two orthogonal directions, the rigidity in the orthogonal direction is increased, and as a result, shape holding properties in all directions are exhibited.

The mesh sheet 10 will be described with reference to FIGS. 2 and 3 (note that the shape retention band 6 is not shown in FIGS. 2 and 3).
As shown in the surface view of FIG. 2, 1 is a main body part, and 2 is an edge. Although only a part of the figure is shown, the actual mesh sheet 10 is a quadrangular sheet-like material having a vertical dimension of about 1.0 to 2.1 m and a horizontal dimension of about 2 to 50 m.
In addition, this dimension is determined from the ease of enforcement work, transportation, etc., and there is no restriction | limiting in the dimension as invention.

  Both ends of the main body 1 (for example, upper and lower ends; however, only the upper end is shown in FIG. 2) are end edges 2. Both the main body 1 and the edge 2 are mesh sheets in which reinforcing bars 3 are formed in a net shape, but the sizes of the meshes are different. The opening S1 of the main body 1 is 5 to 20 mm both vertically and horizontally, and is preferably about 10 mm. On the other hand, the opening S2 of the end edge 2 is about 0.5 to 2 mm in both length and width, and particularly preferably about 1 mm.

The opening of the main body 1 is not so clogged, but this is a numerical value selected to reduce the weight and prevent a small piece of concrete from falling off. In addition, the opening of the main body 1 is a numerical value selected so that the deterioration of the concrete progresses after the installation of the net and the peeling of the concrete piece can be confirmed through an infrared photograph.
The opening of the edge 2 is a numerical value selected to give strength to fix the concrete piece protection net A to the concrete surface without being broken even if the anchor bolt is penetrated.

The reinforcing bar 3 has a core wire made of vinylon fiber. A core wire made of vinylon fiber is characterized by high flexibility and high tensile strength.
High flexibility means that it is rich in flexibility, and can be applied even if there are small irregularities or corner portions with a small curvature on the construction surface. Also, the high tensile strength can withstand the weight of a large piece of concrete and prevent it from falling, and can also be prevented from being broken at the edge of the piece of concrete.

The reinforcing bar 3 has a vinylon fiber as a core wire 31 and a PVC coating 32 formed on the outer peripheral surface thereof.
Since the PVC coating is excellent in weather resistance, it does not deteriorate even when exposed to ultraviolet rays or the like over a long period of time. Moreover, since it has flame retardancy, even if it is in a fire or solar heat accumulates high heat, it becomes difficult to deteriorate.
In addition, as a film of the core wire 31, you may coat | cover not only with PVC but what has the same performance, or what has a weather resistance, for example, a silicon resin, a fluororesin, etc.

In the present embodiment, the reinforcing bar 3 is formed as a single reinforcing bar by combining two core wires 31 with a coating. When the number is two, the strength is increased, but the number is not limited to this, and the number may be one or three.
Moreover, the two core wires 31 with a film may be twisted with each other or may be simply arranged in parallel.

As shown in the rear view of FIG. 3, an adhesive layer 4 is formed on the rear surface of the edge 2. This adhesive layer 4 is provided to temporarily fix the mesh sheet 10 to the concrete surface. In order to form the adhesive layer 4, an appropriate adhesive may be applied, or a double-sided tape may be applied.
The adhesive layer 4 only needs to have an adhesive force that holds the weight of the mesh sheet 10 so as not to slip off until the anchor bolt is driven.
Although not shown in the drawing, the adhesive layer 4 may be formed on both ends of the main body 1 (for example, upper and lower ends; however, only the upper end is shown in FIG. 2). However, the adhesive layer 4 is not essential in the present invention, and those that are not used at all or those in which the adhesive layer 4 is formed only at one end are also included in the present invention.

As is clear from the configuration of the mesh sheet 10 described above, the mesh sheet 10 mainly composed of vinylon fibers is rich in flexibility.
The shape-retaining band 6 shown in FIG. 1 imparts rigidity to the mesh sheet 10, and the material is made by impregnating a glass fiber with a thermosetting synthetic resin having alkali resistance. More specifically, glass fiber bundles are aligned and impregnated with an alkali-resistant thermosetting synthetic resin such as polyester resin, vinyl ester resin, or epoxy resin, and hardened.

The glass resin has high tensile strength but low rigidity, but by adding a synthetic resin to the glass resin, resistance to bending is imparted to increase the rigidity.
Moreover, since the synthetic resin contained in the glass fiber has high alkali resistance, it is not deteriorated by an alkaline component leached from the concrete.

The integration of the shape retention band 6 and the mesh sheet 10 can be realized by the following method. A heat pressing method is suitable, and upper and lower molds are used for this. Among the molds, those obtained by processing grooves for forming the shape retaining band 6 on the bottom surface of the lower mold and the upper surface of the upper mold are used.
The glass fibers containing the synthetic resin are arranged on the lower mold so as to be arranged, and the mesh sheet 10 is arranged thereon. Further, another glass fiber (containing a synthetic resin) is placed on the mesh sheet 10, and an upper mold is set thereon. In this state, both the front and back surfaces of the mesh sheet 10 are sandwiched between glass fiber bundles.

  Next, the upper and lower molds are tightened and placed in a hot stove. In this manner, the shape retention bands 6 are strongly integrated on both the front and back surfaces of the mesh sheet 10 by heating and pressurizing, due to the curing of the thermosetting resin. When the mold is removed after a predetermined time and cooled, the concrete piece protection net A is completed. Since the mesh sheet 10 and the shape retaining band 6 integrated in this way are firmly joined, they are attached to a curved surface such as a tunnel, so that they remain integrated without being separated from each other even if they are bent. It becomes possible to construct.

FIG. 4A shows an anchor bolt 5 for attaching the concrete piece protection net A. FIG.
The anchor bolt 5 has a hollow cylinder 51, and a crack 52 is formed at the tip thereof. A plug 53 is inserted inside the cylinder 51. 55 is a plate and 56 is a washer. The plate 55 is a large rectangular washer having a side of about 60 mm.

FIG. 4B shows the usage state of the anchor bolt 5.
A hole is drilled in the concrete wall Cw, the concrete piece protection net A of the present invention is placed in the concrete Cw, and the anchor bolt 5 is inserted into the hole through the plate 55 and the washer 56. When the plug body 53 is struck with a dedicated tool, the crack 52 is opened and spreads to the tip of the bolt. Subsequently, when the liquid solidifying agent 57 is injected from the proximal end of the cylindrical body 51, the solidifying agent 57 is filled inside and outside the cylindrical body 51.

  Thereafter, when the solidifying agent 57 is hardened, the anchor bolt 5 whose tip is open will not come off. In addition, since rainwater or the like does not enter the concrete from the outside, corrosion of the internal reinforcing bars can be prevented. The anchor bolt 5 is not limited to the above, and can be used without particular limitation as long as it performs the same function.

Next, a construction method of the concrete piece protection net A on the construction surface will be described with reference to FIGS. 5 and 6.
As shown in FIG. 5, anchor bolts 5 are passed through appropriate positions of the main body 1 and the edge 2 of the concrete piece protection net A. An arbitrary part of the mesh sheet 10 may be selected as the location and number of the anchor bolts 5 to pass, and the anchor bolts 5 may be attached so as not to fall after construction.

Next, a construction method for the inner wall surface of the tunnel T will be described with reference to FIG.
When constructing the concrete piece protection net A on the curved inner wall of the tunnel T, the worker stands on an aerial work vehicle or a scaffold and drives the anchor bolt 5 while holding the concrete piece protection net A. At this time, although the concrete piece protection net A is flexible enough to follow the curved surface, it has a shape retaining property so that it does not bend or hang down. Is not necessary and construction work can be easily performed.

  Since the anchor bolt 5 can be fixed freely as described above, the size and construction of the concrete piece protection net A is not limited to the upper and lower edges but also the right and left edges and the appropriate place inside the main body 1. What is necessary is just to carry out suitably according to the shape of a concrete surface.

  If the construction surface is large and the area of the concrete piece protection net A is small, a plurality of concrete piece protection nets A may be used. In this case, the side edges of the concrete piece protection net A are overlapped and anchored. The main material is vinylon fiber that can secure sufficient strength even if the mesh sheet 10 is finished thin with bolts 5 and the synthetic resin impregnation that can secure sufficient rigidity even if the shape retaining strip 6 is also finished thin. Since the glass fiber is used, it can be attached to the wall surface with the anchor bolt 5 so as not to cause a gap by overlapping.

  In the concrete piece protection net A of the present embodiment, the main body 1 of the mesh sheet 10 has a large mesh, so the weight is light. However, even a small concrete piece has an opening that does not allow passage, and the strength is high. Regardless of its size, it can be effectively prevented from coming off.

  Moreover, since the shape retention band 6 is impregnated with a thermosetting synthetic resin having alkali resistance, the alkali resistance is high, and it is not deteriorated by an alkali component in the concrete after construction. For this reason, the good performance of the concrete piece protection net A can be maintained over a long period after construction.

  Furthermore, since the reinforcing bar 3 constituting the mesh sheet 10 has a PVC coating 32 and is excellent in ultraviolet resistance, it is also suitable for construction near the tunnel entrance.

  Further, since the mesh sheet 10 is fine on the whole, the mesh sheet 10 is not easily noticeable, and the shape retaining band 6 is also thinly finished, so that the appearance is not conspicuous. For this reason, the scenery after construction is good.

  Moreover, since the vinylon fiber constituting the reinforcing bar 3 of the mesh sheet 10 only stretches about 5% even when a load is applied, when the plate 55 that presses this against the construction surface is made to be highly rigid, even if the concrete peels off A piece can fall and catch it firmly. That is, since the mesh sheet 10 is hardly stretched, the concrete piece protection net A can be held without dripping even if the concrete piece is dropped, so that the traveling safety in the tunnel is maintained. The high-rigidity plate 55 may be made of metal, or made of synthetic resin and thick.

  In the above embodiment, application to a tunnel has been described. However, the present invention is not limited to this and can be applied to any concrete structure.

1 Body 2 Edge 3 Reinforcement 4 Adhesive Layer 5 Anchor Bolt

Claims (5)

It consists of a mesh sheet that receives the stripped pieces of concrete, and a shape retention band that gives shape retention to the mesh sheet,
The mesh sheet is a sheet in which reinforcing bars whose core wires are vinylon fibers are formed in a net shape,
The mesh of the main body has an opening of 5 to 20 mm,
The shape-retaining belt is attached to the mesh sheet protection net in at least one direction on the surface of the mesh sheet. The concrete piece protection net according to claim 1, wherein the shape retaining bands are attached in a direction crossing each other on the surface of the mesh sheet. 2. The concrete piece protection net according to claim 1, wherein the shape retention band is obtained by impregnating a glass fiber with a thermosetting synthetic resin having alkali resistance. 2. The concrete piece protection net according to claim 1, wherein the reinforcing bar is formed with a weather-resistant synthetic resin film on the outer periphery of the core wire. 4. The concrete piece protective net according to claim 3, wherein the synthetic resin coating is a PVC coating.