Grid bar fixing device and structure to prevent spalling of concrete structure

Abstract

To provide a lattice bar fastener and a structure for preventing spalling of a concrete structure, which enables the lattice bar fastener to be positioned and attached to a resin lattice bar by a simple method and improves the performance of preventing the resin lattice bars from falling off. [Solution] A flat lattice bar fastener 10, the flat plate being large enough to close each of the square boxes 22 formed in the resin lattice bar 20, the boundary between the flexible bone section 13 and the support frame section 12 of the flat plate being recessed to provide multiple protruding corners 15 on the bottom side of the flat plate, and the outer peripheral surfaces of the multiple protruding corners 15 are formed so as to be inscribed in the multiple inner corners 23c of the boxes 22 formed in the resin lattice bar 20.

Description

[Technical field]

[0001] The present invention relates to a lattice bar fastener for pressing and fixing resin lattices to the wall surface of a concrete structure, and to a structure for preventing spalling of the concrete structure. [Background technology]

[0002] In concrete structures such as tunnels and viaducts, the concrete surface layer has deteriorated, causing concrete pieces to spall off from the wall. For this reason, various methods have been proposed to prevent concrete spalling.

[0003] Patent Document 1 discloses a method for preventing spalling in which a resin lattice bar is fixed to a concrete surface using a washer and an anchor bolt. Resin lattice bars are high-strength net-like structures made by impregnating high-performance continuous reinforcing fibers such as carbon and glass into resin and forming multiple reinforcing bars at intervals across each other in both the vertical and horizontal directions into a single unit.

[0004] A washer 60 described in Patent Document 1 will be described with reference to FIG. This washer 60 is made of a square metal plate that can be fitted onto one square of the resin lattice bar 20. The washer 60 has a circular recess 61 formed in its center, the recess 61 having a depth equal to the thickness of the reinforcing bar 21 of the resin lattice bar 20, and a bolt hole 62 formed in the center of the recess 61. Furthermore, the washer 60 has a pair of locking claws 63, 63 formed by bending the extensions, which are extended in a band shape from the opposing sides of the metal plate, at a right angle.

[0005] The method of preventing spalling using the washer 60 and the anchor material 30 involves laying the resin lattice bars 20 on the wall surface of a concrete structure, and then placing the washer 60 on the outer surface of the lattice bars 20. At this time, a pair of locking claws 63, 63 are fitted onto the reinforcing bars 21 of the resin lattice bars 20 to prevent the washer 60 from shifting out of position. A washer 60 is inserted through the head of the anchor material 30 driven into the wall surface 41, and the washer 60 is pressed against the wall surface 41 to fix the resin lattice reinforcement 20 in place.

[0006] The conventional washer 60 has the problem that it blocks one of the squares formed in the resin lattice reinforcement, making it impossible to visually check the condition of the wall surface 41 of the concrete structure 40 near the anchor bolt 65.

[0007] Referring to FIG. 8, Patent Document 2 discloses a washer 70 that makes the wall surface near the anchor material 30 visible. This washer 70 consists of a metal plate slightly larger than one square of resin lattice reinforcement, with a support frame portion 71 formed on the outer edge of the metal plate, and radially flexible bone portions 73 and multiple open windows 74 formed between the support frame portion 71 and a center portion 72 of the metal plate. Furthermore, this washer 70 has four claw portions 75 formed by bending the ears extending from the corners of the metal plate, and these four claw portions 75 are hooked onto the outer peripheral surface of the four corners of the resin lattice bar 20 to prevent the washer 70 from shifting out of position. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2006-9266 A [Patent Document 2] JP 2017-14760 A Summary of the Invention [Problem to be solved by the invention]

[0009] The above-mentioned conventional techniques have the following problems. <1> When the washer 60 is formed with a pair of locking claws 63, 63 as in Patent Document 1, the locking claws 63, 63 are fitted on the resin lattice bar 20 for positioning. Therefore, the dimension W of one side of the metal plate constituting the washer 605 The outer dimension W of the square of the resin lattice bar 20 3 Since the dimensions are slightly larger than the above, the cost of steel increases, and the manufacturing cost of the washer 60 becomes higher. <2> The washer 60 described in Patent Document 1 requires that the size and depth of the recesses 61 be individually designed to match the size of the squares of the resin lattice reinforcement 20 and the thickness of the reinforcing bars, resulting in high manufacturing costs for the washer 60. <3> The washer 70 described in Patent Document 2 must be formed with a dimension such that the claw portion 75 can straddle the reinforcing bars 21 of the resin lattice bars 20 and be externally mounted, which increases the manufacturing cost of the washer 70.

[0010] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a lattice bar fastener and a structure for preventing spalling of a concrete structure that can solve the problems of the conventional techniques described above. [Means for solving the problem]

[0011] The present invention is a flat lattice bar fixing device which includes a bolt hole formed through the center of the flat plate, a flexible bone portion extending radially from the central portion to the support frame portion between a support frame portion extending around the periphery of the flat plate and a plurality of open windows, and a plurality of open windows defined between the support frame portion and a pair of flexible bone portions, and which fixes a plurality of resin lattice bars by pressing them against the wall surface of a concrete structure using an anchor material driven into the wall surface of the concrete structure, wherein the flat plate is large enough to close individual square boxes formed in the resin lattice bar, the flat plate has a plurality of protruding corners which are recessed at the boundary between the flexible bone portion and the support frame portion and protrude toward the bottom surface of the plate, and the outer peripheral surfaces of the plurality of protruding corners are formed so as to be inscribed in a plurality of inner corners of the boxes formed in the resin lattice bar. In another embodiment of the present invention, the outer circumferential surface of the protruding corner portion is formed in an L-shape in a plan view. In another embodiment of the present invention, the protruding length of the protruding corner portion is shorter than the thickness of the resin lattice reinforcement. In another embodiment of the present invention, four radial bones extend radially from the central portion to the support frame. In another embodiment of the present invention, the support frame portion is formed to be smaller than the outer dimensions of a lattice frame that defines the squares of the resin lattice reinforcement bars. The present invention is a structure for preventing spalling of a concrete structure, which is equipped with any one of the lattice bar fasteners described above, and comprises resin lattice bars formed by crossing resin reinforcing bars at intervals to form a lattice pattern and stretched over the wall surface of a concrete structure, a plurality of lattice bar fasteners arranged on the outer surface of the resin lattice bars, and anchor materials fixed into the concrete structure with their heads protruding from the wall surface, with a plurality of protruding corners protruding from the bottom side of the lattice bar fasteners fitted into the squares of a lattice frame to position them and fixed with the anchor materials. In another form of the present invention, the central portion of the lattice bar fastener is fixed to the wall surface by the anchor material, and the support frame portion of the lattice bar fastener presses the lattice frame of the resin lattice bar against the wall surface via the deflection of the flexible bone portion, thereby fixing the lattice frame. In another embodiment of the present invention, a net-like mesh material having smaller squares than the squares of the resin lattice bars is interposed between the resin lattice bars and the wall surface. Effect of the Invention

[0012] The present invention has at least one of the following advantages. <1> By simply forming multiple protruding corners in a lattice bar fastener having multiple open windows, the multiple protruding corners can be fitted into the inner corners of the squares formed in the plastic lattice bar, so that the outer peripheral surfaces of the multiple protruding corners can be brought into contact with the inner corners of the squares of the plastic lattice bar. This not only prevents the plastic lattice bar from sliding lateral to the lattice bar fastener and allows it to be positioned and attached in the correct position, but the restraining action of the multiple protruding corners by the squares improves the efficiency of load transfer between the lattice bar fastener and the lattice frame, making the lattice bar fastener much better at preventing the plastic lattice bar from peeling off than before. <2> By forming multiple protruding corners in the lattice bar fastener, the effect of suppressing bending deformation of the lattice bar fastener during use is increased. Therefore, even if an open window is provided in the lattice bar fixing device to allow visual inspection of the deterioration of the wall surface, the open window is unlikely to become a weak point in terms of strength. <3> Since the lattice bar fastener can be positioned without providing a locking claw member on the outer edge thereof, the lattice bar fastener can be designed compactly. This not only improves the ease of transport and handling of the lattice bar fasteners, but also saves on materials, making them cheaper to manufacture. <4> The elastic force generated when the flexible bone section is bent not only enables the plastic lattice bars to be elastically fixed to the wall surface through the lattice bar fixing device, but also effectively prevents the nuts from loosening and the plastic lattice bars from shifting out of position. [Brief description of the drawings]

[0013] [Figure 1] An explanatory diagram of a method for attaching a resin lattice bar using the lattice bar fastener according to the present invention. [Diagram 2] In this diagram, (a) is a plan view of the lattice fixture, (b) is an enlarged cross-sectional view of the protruding corner, and (c) is a plan view of part of the plastic lattice. [Diagram 3] Illustration of how to install plastic lattice bars [Figure 4] Illustration of how to fasten the lattice fixture [Diagram 5] Plan view of part of the plastic lattice reinforcement after fixing [Figure 6] FIG. 1 is an explanatory diagram of a lattice bar fixture as a comparison example without an open window; (a) is a plan view of the lattice bar fixture, and (b) is an enlarged cross-sectional view of the bent part of the lattice bar fixture. [Figure 7] FIG. 1 is an explanatory diagram of a method for installing a plastic lattice bar using a conventional washer; (a) is a perspective view of the washer installation method, and (b) is a cross-sectional view of the plastic lattice bar after installation is complete. [Figure 8] An explanatory diagram of a conventional method for installing plastic lattice bars using other washers. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will now be described in detail with reference to the drawings.

[0015] <1> Concrete Structures In this specification and claims, "wall surface 41" refers to the concrete surface of concrete structure 40, but is not limited to vertical surfaces such as shaft walls and side walls, and includes all concrete surfaces where concrete spalling may occur, such as ceiling surfaces.

[0016] <2> Plastic lattice bars The resin grid bars 20 will be described with reference to Figures 1 and 2. The resin grid bars 20 are reinforcing members with a mesh structure for covering and reinforcing the wall surfaces 41 of a concrete structure 40, and are formed into a grid shape by crossing reinforcing bars 21 made of FRP (fiber reinforced plastic), which is made by impregnating vinyl ester resin with high performance continuous fibers such as carbon fibers, at specified intervals.

[0017] <2.1> Mesh material If necessary, an FRP mesh material 25 is attached to the bottom side of the resin lattice reinforcement 20. The mesh material 25 is a net-like material made of FRP, and has mesh sizes smaller than the squares of the resin lattice bars 20. The mesh material 25 is not essential, and the mesh material 25 may be omitted and the resin lattice reinforcement 20 may be used alone.

[0018] <2.2> Squares The resin lattice bars 20 form quadrangular (square or rectangular) cells 22 between a plurality of reinforcing bars 21 arranged crosswise in the vertical and horizontal directions. The grid interval of the squares 22 is appropriately selected, but in practice it is 50 to 100 mm.

[0019] <2.3> Lattice frame In this example, a structure surrounded by four reinforcing bars 21 to define squares 22 is defined as a lattice frame 23 for explanation. The lattice frame 23 has a rectangular outer surface 23a, four smoothly formed inner sides 23b on its inside, and four inner corners 23c formed at right angles to the corners of two adjacent inner sides 23b.

[0020] <3> Lattice bar fixture The lattice bar fastener 10 according to the present invention is a flat fastener having a substantially square shape in plan view, which is used in combination with anchor materials 30 to press and fasten resin lattice bars 20 to a wall surface 41 of a concrete structure 40.

[0021] In the following explanation, the "bottom surface" of the lattice bar fastener 10 refers to the surface that faces the wall surface 41 when in use, and the "front surface" refers to the opposite surface.

[0022] <3.1> Overview of lattice bar fixing device The lattice bar fastener 10 comprises a central portion 11, a support frame portion 12, a plurality of flexible bone portions 13, a plurality of open windows 14, and a plurality of overhanging corner portions 15. In this embodiment, the lattice bar fastener 10 is provided with four open windows 14 and four flexible bone portions 13. As shown in FIG.

[0023] The material for the flat plate constituting the lattice bar fastener 10 may be, for example, a steel plate, a stainless steel plate, an aluminum plate, a resin plate, an FRP plate, etc., but in consideration of economy and workability, etc., a steel plate is preferable.

[0024] <3.2>Central part The central portion 11 is the center of the lattice bar fastener 10, and is the portion that is pressed against and fixed to the wall surface 41 by the anchor material 30 when in service. The central portion 11 has a bolt hole 11a at its center through which an anchor material 30 can be inserted.

[0025] <3.3> Support frame The support frame portion 12 is the outer peripheral portion of the lattice bar fastener 10 that has a square shape. The support frame portion 12 is a portion that is only to be brought into contact with the outer surface 23a of the lattice frame 23, and is not provided with claw members for hooking onto the lattice frame 23 as in the conventional case.

[0026] Referring to FIG. 2, the outer and inner dimensions of the support frame 12 are W 1 , W 2 The outer and inner dimensions of the lattice frame 23 are W 3 , W 4In this case, the outer dimensions W of the support frame 12 in the vertical and horizontal directions are 1 is the outer dimension W of the lattice frame 23 3 The inner dimension W of the frame portion 12 in the vertical and horizontal directions is approximately the same as 2 Also, the inner dimension W of the lattice frame 23 4 It is almost the same as: In other words, the inner and outer dimensions W 1 , W 2 is the inner and outer dimension W of the lattice frame 23 3 , W 4 It will never exceed.

[0027] <3.4> Radius Between the central portion 11 of the lattice bar fastener 10 and the peripheral support frame portion 12, a plurality of flexible bone portions 13 are formed radially. The flexible bone portion 13 is a band-shaped portion that integrally connects the center portion 11 and the corner portions of the support frame portion 12 .

[0028] In this example, a form in which four flexures 13 are formed along the diagonal lines of the lattice bar fastener 10 will be described, but the number of flexures 13 formed may be four or more.

[0029] <3.5> Overhang corner The flexible bone portion 13 is recessed toward the bottom surface at the boundary with the support frame portion 12, and a protruding corner portion 15 is formed at the boundary between the flexible bone portion 13 and the support frame portion 12. The reason for forming multiple protruding corners 15 on the lattice bar fastener 10 is to bring the protruding corners 15 of the lattice bar fastener 10 into contact with the inner corners 23c of the lattice frame 23, thereby restraining the multiple protruding corners 15 and increasing the rigidity of the lattice bar fastener 10, and ultimately significantly increasing the supporting force of the lattice bar fastener 10 against the lattice frame 23.

[0030] By recessing the boundary between the bent rib portion 13 and the support frame portion 12 toward the bottom surface side, a step is generated between the support frame portion 12 and the bent rib portion 13. This step portion becomes the protruding corner portion 15.

[0031] <3.5.1> Cross-sectional shape of the outer peripheral surface of the protruding corner The protruding corner portion 15 is a protrusion that can be inscribed within the squares 22 of the lattice frame 23. The protruding corner portion 15 has an outer peripheral surface 15a that is L-shaped in plan view and can be inscribed in an inner corner portion 23c formed at the corner portion of the square 22. The outer peripheral surface 15a of the projecting corner portion 15 does not need to be machined to a highly accurate right angle, but may be formed into an L-shape that is nearly a right angle.

[0032] <3.5.2> Projection angle of overhanging corner The protruding angle of the overhanging corner portion 15a with respect to the support frame portion 12 will be described with reference to FIG. 2(b). The protruding corner portion 15 protruding toward the bottom surface side from the support frame portion 12 is bent at an angle close to a right angle. That is, the inner and outer peripheral surfaces of the protruding corner portion 15 are slightly inclined from the front surface side to the back surface side.

[0033] <3.5.3> Inside and outside dimensions of overhanging corners The inner and outer dimensions of the projecting corner portion 15a will be described with reference to FIGS. When the lattice bar fastener 10 is viewed in plan from the front side, if the outer dimension of a pair of adjacent protruding corner portions 15 is A and the inner dimension of a pair of adjacent protruding corner portions 15 is B, the inner dimension B of the protruding corner portions 15 is smaller than the outer dimension A of the support frame portion 12, and there is a dimensional difference G between the two inner and outer dimensions A and B. The outer dimension A of the protruding corner portion 15 means the distance between the boundary between the support frame portion 12 and the protruding corner portion 15, and the inner dimension B of the protruding corner portion 15 means the distance between the boundary between the protruding corner portion 15 and the flexural bone portion 13.

[0034] When the plate thickness of the lattice bar fastener 10 is t, in the present invention, the dimensional difference G is 1.0t to 2.0t. In practice, if the plate thickness t is 1.5 mm, the dimensional difference G will be approximately 1.5 mm. As the difference G between the inner and outer dimensions A and B becomes smaller, the bending angle of the protruding corner portion 15 with respect to the support frame portion 12 or the flexural portion 13 approaches a right angle. The dimensional difference G between the two inner and outer dimensions A and B is made small in order to ensure surface contact between the outer peripheral surface 15a of the protruding corner portion 15 and the inner surface of the inner corner portion 23c of the lattice frame 23 when the lattice bar fastener 10 is in use. In other words, when the dimensional difference G between the two inner and outer dimensions A and B becomes large, the inclination of the outer peripheral surface 15a of the protruding corner portion 15 becomes gentler, and there is line contact between the outer peripheral surface 15a of the protruding corner portion 15 and the inner surface of the inner corner portion 23c of the lattice frame 23, and the restraining action of the squares 22 can no longer be exerted. In the present invention, in order to restrain the protruding corner portion 15 to the squares 22, the outer circumferential surface 15a of the protruding corner portion 15 is formed to approach a right angle.

[0035] <3.5.4> Projection dimensions of overhanging corners In order to generate a resilient force in the flexible bone portion 13 when the lattice bar fastener 10 is in use, the protruding dimension (protruding dimension) of the protruding corner portion 15 toward the bottom surface side is set so as not to exceed the thickness of the reinforcing bar 21. A protruding dimension of the protruding corner portion 15 toward the bottom surface side of about 1.5 to 3 mm is sufficient.

[0036] <3.6> Open window A plurality of open windows 14, each of which has a substantially triangular shape in plan view, are formed between the central portion 11, the support frame portion 12, and the pair of radial bone portions 13. The open window 14 is an opening for visually observing the rear wall surface 41 when the lattice bar fastener 10 is in use, and also functions to facilitate bending of the protruding corner portion 15.

[0037] <3.6.1> Number of open windows In this example, an embodiment in which four open windows 14 are formed in the lattice bar fastener 10 will be described, but the number of open windows 14 may be four or more.

[0038] <3.6.2> Relationship between open windows and bending of overhanging corners The relationship between the open window 14 and the bending process of the projecting corner portion 15 will be described. To explain this with reference to the comparative example of the lattice bar fastener shown in Figure 6, if one were to perform press working to form a recess of about 2 to 3 mm deep in the lattice bar fastener without providing an open window 14, it would be technically difficult to process the bent part at an angle close to a right angle, and the bent part would have to be bent at a gentle angle.

[0039] In the present invention, by providing a plurality of open windows 14 on the inside of the support frame portion 12 of the lattice bar fastener 10, bending (pressing) of the metal plate becomes easier, and the protruding corner portion 15, which is the bending portion, can be bent at a right angle or an angle close to a right angle.

[0040] <4> Anchor Material The anchor material 30 is a known anchor member for fixing the resin grid bars 20 to the wall surface 41 of the concrete structure 40 via the grid bar fastener 10. As the anchor material 30, for example, a known expansion anchor of a core rod driving type can be used. The anchor material 30 is not limited to an expansion anchor, but adhesive or screw-in anchors, etc. may also be used.

[0041] [How to install plastic lattice bars] A mounting method for fixing the resin lattice bars 20 to the wall surface 41 using the lattice bar fastener 10 and the anchor material 30 will be described with reference to Figs.

[0042] <1> Fixing the anchor material After a wall surface 41 of a concrete structure 40 is subjected to a base preparation, anchor materials 30 are fixed into anchor holes drilled at predetermined positions in the wall surface 41 (FIG. 3).

[0043] <2> Plastic lattice bar covering A resin lattice bar 20 is stretched over and covers a wall surface 41 of a concrete structure 40 in which a plurality of anchor materials 30 are embedded (FIG. 3). At this time, the resin lattice reinforcement 20 is applied to cover the wall surface 41 so that the anchor material 30 is positioned at the center of the lattice frame 23 .

[0044] In a configuration in which the mesh material 25 is attached to the bottom side of the resin lattice reinforcement 20, the mesh material 25 is installed so as to be in contact with the wall surface 41.

[0045] Although the above describes a form in which the anchor material 30 is fixed in advance, it is also possible to first position the resin lattice bars 20 and the lattice bar fasteners 10 on the wall surface 41, and then drive the anchor material 30 into the wall surface 41 so as to pass through them and fix them.

[0046] <3> Fixing plastic lattice bars The resin lattice bars 20 are fixed to the wall surface 41 through the following steps.

[0047] <3.1> Positioning of grid fixtures While inserting the head of the anchor material 30 through the bolt hole 11a of the lattice bar fastener 10, the lattice bar fastener 10 is placed over the lattice frame 23 of the resin lattice bar 20, and the bottom surface of the support frame portion 12 is abutted against the outer surface 23a of the lattice frame 23 (Figure 4). At this time, the four sets of protruding corner portions 15 protruding from the bottom side of the lattice bar fastener 10 are fitted into the squares 22 of the lattice frame 23 (FIG. 5).

[0048] The lattice bar fastener 10 has a plurality of protruding corner portions 15 formed thereon in accordance with the inner dimensions of the squares 22 of the lattice frame 23. Therefore, when setting the lattice bar fastener 10 on the head of the anchor material 30, the protruding corner portions 15 of the lattice bar fastener 10 are fitted into the squares 22 of the lattice frame 23, so that the outer peripheral surfaces of the four sets of protruding corner portions 15 abut against the inner surfaces of the inner corner portions 23c of the squares 22 of the lattice frame 23, thereby making it easy to position the lattice bar fastener 10.

[0049] <3.2> Tightening of lattice bar fasteners A nut 31 is screwed onto the head of the anchor material 30 protruding from the central portion 11 of the lattice bar fastener 10 . By tightening the nut 31, a pressing force is generated in the center portion 11 of the lattice bar fastener 10 toward the wall surface 41. This pressure is transmitted to the support frame 12 through the multiple flexible bones 13, and is finally supported by the wall surface 41 through the lattice frame 23 with which the bottom surface of the support frame 12 comes into contact.

[0050] By further tightening the nut 31, the elastic contact force between the bottom surface of the support frame portion 12 of the lattice bar fastener 10 and the outer surface 23a of the lattice frame 23 increases, causing bending deformation in the multiple flexible bone portions 13.

[0051] <3.3> Generation of elastic force The bending of the multiple flexible bone sections 13 generates a resilient force (spring force), which causes the lattice bar fixing device 10 to hold down the entire area of ​​each square of the lattice frame 23, thereby firmly fixing the resin lattice bar 20 to the wall surface 41 of the concrete structure 40. Furthermore, the elastic force generated in the flexible bone portion 13 can effectively prevent the nut 31 fastening the lattice bar fastener 10 from loosening.

[0052] <3.4> Visibility of the wall through an open window In the present invention, one of the squares 22 of the resin lattice 20 is covered with the lattice fixture 10, but the wall surface 41 can be seen through the open window 14 of the lattice fixture 10. Therefore, after the resin lattice bars 20 are attached, the deterioration condition of the wall surface 41 can be visually inspected through the open window 14 of the lattice bar fastener 10.

[0053] <4> Regarding the mounting strength of plastic lattice bars The mounting force of the resin lattice bars 20 fixed to the wall surface 41 of a concrete structure 40 using the lattice bar fastener 10 and the anchor material 30 will be examined.

[0054] <4.1> Strength test of grid bar fixing device A lattice bar fastener 10 having multiple protruding corners 15 of the present invention, a flat lattice bar fastener of the same dimensions but omitting the protruding corners, and a plastic lattice bar 20 with each side measuring 1 m square are prepared.

[0055] Anchor materials were driven into the four peripheral points of the square plastic grid 20, and the grid fixtures were fixed at equal intervals. The tension member of the testing machine was hooked to the center of the plastic grid 20, which was the test piece, and the tension member was pulled to apply a peeling force to the plastic grid 20, thereby testing the attachment force of the plastic grid 20 by the grid fixtures.

[0056] <4.2> Test results As a result of the test, it was confirmed that the lattice bar fastener 10 of the present invention, which is equipped with multiple protruding corner portions 15, has a significantly higher mounting force for the plastic lattice bar 20 than the comparative lattice bar fastener which only omitted the protruding corner portions. In other words, the lattice bar fastener 10 of the present invention has a significantly higher peeling prevention performance than the comparative lattice bar fastener.

[0057] <4.3> Factors for performance improvement The lattice bar fastener 10 of the present invention exhibits excellent anti-peeling performance because the outer peripheral surface 15a of the protruding corner 15 formed on the lattice bar fastener 10 comes into contact with the inner surface of the inner corner 23c of the lattice frame 23, thereby preventing lateral sliding of the plastic lattice bars 20 and increasing the gripping force between the lattice bar fastener 10 and the lattice frame 23, thereby improving the load transmission efficiency.

[0058] <4.3.1> Anti-slip effect of grid fixing fixtures The lateral slippage of the lattice bar fastener shown in FIG. 6 as a comparison example will now be described. If the outer dimension of the bent part of the lattice bar fastener is A and the inner dimension of the bent part is B, then if the plate thickness of the lattice bar fastener is, for example, 1.5 mm, the minimum dimensional difference G between the two inner and outer dimensions A and B will be approximately 5 mm, and the bending angle of the bent part will be 20 to 30°. When this comparative lattice bar fixing device is in use, the contact between the outer surface of the bent portion and the plastic lattice bar becomes a line contact, which weakens the gripping force, making it easier for the plastic lattice bar to move laterally relative to the lattice bar fixing device.

[0059] If large lateral movement of the plastic lattice bars is permitted, the following problems will arise: For example, if plastic lattices are attached to the ceiling surface of a tunnel, a downward load will be applied to the plastic lattices if pieces of concrete or the like fall off. The load applied to the plastic lattice bars is supported by the fixed part of the lattice bar fixing device, but if the plastic lattice bars move laterally at that fixed part, the downward bending deformation of the plastic lattice bars themselves will become large, which will cause an obstruction to the tunnel space. Therefore, when installing plastic lattice bars on a tunnel body, it is necessary to minimize the lateral movement of the plastic lattice bars as much as possible.

[0060] In the present invention, the lateral movement of the resin lattice bars 20 relative to the lattice bar fastener 10 can be reliably restricted, thereby solving the above-mentioned problems.

[0061] <4.3.2> Improving load transmission efficiency By bringing the protruding corners 15 formed on the lattice bar fastener 10 into contact with the inner corners 23c of the lattice frame 23, the multiple protruding corners 15 are restrained, increasing the rigidity of the lattice bar fastener 10. As a result, the bending deformation at the corners of the support frame portion 12 of the lattice bar fastener 10 is smaller than that at the straight portions of the support frame portion 12, and the engagement force between the lattice bar fastener 10 and the lattice frame 23 is increased, resulting in improved load transmission efficiency.

[0062] As a means for increasing the load transfer efficiency between the lattice bar fastener 10 and the lattice frame 23 without forming the protruding corner portion 15, a method of increasing the bending rigidity of the lattice bar fastener 10 by increasing the overall plate thickness of the lattice bar fastener 10 can be considered. If the plate thickness of the lattice bar fastener 10 is increased, not only will the weight increase, making the lattice bar fastener 10 less portable and easier to handle, but new problems will arise, such as higher manufacturing costs.

[0063] In the present invention, by forming the overhanging corner portion 15, it is possible to increase the bending rigidity of the lattice bar fastener 10 at low cost without increasing the plate thickness of the lattice bar fastener 10. The bending deformation of the multiple flexible bone portions 13 generates a resilient force (spring force), and this resilient force firmly fixes the resin lattice reinforcement 20 to the wall surface 41 of the concrete structure 40. [Explanation of symbols]

[0064] 10... Lattice bar fixture 11...Central part 11a Bolt hole 12 Support frame 13... Radius part 14. Open window 15...Protruding corner 20... Plastic lattice bars 21 Reinforcement 22 squares 23. Lattice frame 23a...Outer surface 23b...inner surface 23c...Inner corner 25 Mesh material 30 Anchor material 31 Nut 40. Concrete structure 41... Wall

Claims

1. A flat lattice bar fastener includes a bolt hole formed through the center of the flat plate, a support frame portion extending around the periphery of the flat plate, a plurality of flexible bone portions extending radially from the center to the support frame portion between the support frame portion and a plurality of open windows, and a plurality of open windows defined between the support frame portion and the pair of flexible bone portions, and is fixed by pressing a plurality of resin lattice bars against the wall surface of a concrete structure using anchor materials driven into the wall surface, The flat plate has a size capable of closing a single rectangular square formed in the resin lattice reinforcement, The bent bone portion is recessed toward the bottom surface of the plate surface, The flat plate has a plurality of overhanging corners formed at the boundary between each of the bent bones recessed toward the bottom surface side of the plate surface and the inner corners of the support frame, The protruding corner portion has an outer peripheral surface that is L-shaped in a plan view, The outer peripheral surfaces of the plurality of protruding corner portions are formed so as to be inscribed in the plurality of inner corner portions of the squares formed in the resin lattice reinforcement by surface contact therewith. Lattice bar fixture.

2. 2. A lattice bar fastener according to claim 1, wherein the protruding length of said overhanging corner portion is shorter than the thickness of said resin lattice bar.

3. 2. The lattice bar fastener according to claim 1, wherein four radial bone portions extend radially from the central portion to the support frame portion.

4. 2. The lattice bar fastener according to claim 1, wherein the support frame portion is formed to be smaller than the outer dimensions of a lattice frame that defines the squares of the resin lattice bar.

5. A structure for preventing spalling of a concrete structure, comprising the lattice bar fastener according to any one of claims 1 to 4, A resin lattice reinforcement bar is formed by crossing resin reinforcing bars at intervals to form a lattice pattern and is extended on the wall surface of a concrete structure; A plurality of lattice bar fasteners arranged on an outer surface of the resin lattice bar; and an anchor material fixed in the concrete structure with a head portion protruding from a wall surface, The plurality of protruding corners protruding to the bottom side of the lattice reinforcement fixture are fitted into the squares of the lattice frame, and the outer peripheral surfaces of the protruding corners are brought into surface contact with the inner corners of the squares to position them and fix them with the anchor material. Structure to prevent spalling of concrete structures.

6. 6. The structure for preventing spalling of a concrete structure according to claim 5, characterized in that the central portion of the lattice bar fastener is fixed to the wall surface by the anchor material, and thereby the support frame portion of the lattice bar fastener presses and fixes the lattice frame of the resin lattice bar against the wall surface via the deflection of the flexible bone portion.

7. 6. A structure for preventing spalling of a concrete structure as described in claim 5, characterized in that a net-like mesh material having smaller squares than the squares of the resin lattice is interposed between the resin lattice and the wall surface.

Images