Lattice bar fixing device and concrete structure peeling prevention structure

Abstract

To provide a lattice bar fixing device and a concrete structure peeling prevention structure, which can position and attach the lattice bar fixing device to a resin lattice bar by a simple method and can improve the peeling prevention performance of the resin lattice bars.SOLUTION: A flat lattice bar fixing device 10 is large enough to close a single square 22 formed in a resin lattice bar 20, and the boundary between a flexible bone section 13 and a support frame section 12 of the flat plate is recessed to form a plurality of protruding corner sections 15 on the bottom side of the flat plate, and the outer surfaces of the plurality of protruding corner sections 15 are formed so as to be inscribed in a plurality of inner corner sections 23c of the square 22 formed in the resin lattice bar 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a grid bar fastener for pressing and fixing resin grid bars 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 surface of the concrete deteriorates, causing concrete pieces to fall off the walls. For this reason, various methods have been proposed to prevent concrete from falling off.

[0003] Patent Document 1 discloses a method for preventing peeling by fixing resin lattice bars to a concrete surface using washers and anchor bolts. 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 integrally molding multiple reinforcing bars that are spaced apart and cross each other vertically and horizontally.

[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 reinforcement 20. The washer 60 has a circular recess 61 formed in the center thereof, the recess 61 having a depth equal to the thickness of the reinforcing bars 21 of the resin lattice bars 20, and a bolt hole 62 formed in the center thereof. Furthermore, the washer 60 has a pair of locking claws 63, 63 formed by bending extensions formed in a strip shape on opposing side surfaces of the metal plate at a right angle.

[0005] The method of preventing spalling using the washer 60 and the anchor material 30 involves spreading the resin grid reinforcement 20 on the wall surface of a concrete structure, and then placing the washer 60 on the outer surface of the grid reinforcement 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 passed 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 side to fix the resin lattice reinforcement 20.

[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 is made of a metal plate slightly larger than one square of resin lattice reinforcement, and has a support frame portion 71 formed on the outer edge of the metal plate, and radial flexible ribs 73 and multiple open windows 74 formed between the support frame portion 71 and the center portion 72 of the metal plate. Furthermore, this washer 70 has four claw portions 75 formed by bending the ear pieces extending from the corners of the metal plate, and these four claw portions 75 are hooked onto the outer peripheral surfaces of the four corners of the resin lattice reinforcement 20 to prevent the washer 70 from shifting out of position. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-9266 [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 a pair of locking claws 63, 63 is formed on the washer 60 as in Patent Document 1, the locking claws 63, 63 are fitted onto the resin lattice 20 to position it. Therefore, the dimension W5 of one side of the metal plate that makes up the washer 60 is slightly larger than the outer dimension W3 of the squares of the resin lattice reinforcement 20, which increases the cost of steel and the manufacturing cost of the washer 60. <2> The washer 60 described in Patent Document 1 requires that the size and depth of the recess 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 size such that the claw portions 75 can be mounted over the reinforcing bars 21 of the resin lattice bars 20, which increases the manufacturing cost of the washer 70.

[0010] The present invention has been made in view of the above points, and has as its object to provide a lattice bar fixing device and a structure for preventing spalling of a concrete structure that can solve the problems of the prior art described above. [Means for solving the problem]

[0011] The present invention provides a flat lattice bar fixing device comprising: a bolt hole formed through the center of the flat plate; a support frame portion extending around the periphery of the flat plate; flexible bone portions extending radially from the center to the support frame portion between the central portion and multiple open windows; and multiple open windows defined between the support frame portion and the pair of flexible bone portions; the flat plate is used to press and fix multiple resin lattice bars using anchor materials driven into the wall surface of a concrete structure; the flat plate is large enough to close individual square boxes formed in the resin lattice bar; the flat plate has multiple protruding corners that are recessed at the boundary between the flexible bone portions and the support frame portion and protrude toward the bottom surface of the plate; and the outer surfaces of the multiple protruding corners are formed so that they can be inscribed in multiple inner corners of the boxes formed in the resin lattice bar. In another embodiment of the present invention, the outer peripheral surface of the protruding corner portion is formed in an L-shape in 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 portion. In another embodiment of the present invention, the support frame portion is formed to have an outer dimension smaller than that 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 grid bar fasteners described above, and which comprises resin grid bars formed by crossing resin reinforcing bars at intervals to form a grid pattern and stretched on the wall surface of the concrete structure, a plurality of grid bar fasteners arranged on the outer surface of the resin grid bars, and anchor materials fixed inside the concrete structure with their heads protruding from the wall surface, and the plurality of protruding corners protruding from the bottom side of the grid bar fasteners are fitted into the squares of the 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 fixing device is fixed to the wall surface by the anchor material, and the support frame portion of the lattice bar fixing device presses and fixes the lattice frame of the resin lattice bar against the wall surface via the deflection of the flexible bone portion. In another embodiment of the present invention, a net-like mesh material having squares smaller than those of the resin lattice bars is interposed between the resin lattice bars and the wall surface. [Effects of the Invention]

[0012] The present invention has at least one of the following advantages. <1> By simply forming multiple protruding corners on a lattice bar fixture with 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 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 sideways relative to the lattice bar fixture and allows it to be positioned and attached in the correct position, but also improves the efficiency of load transmission between the lattice bar fixture and the lattice frame due to the restraining action of the multiple protruding corners by the squares, making the lattice bar fixture much more effective at preventing the plastic lattice bar from peeling off than before. <2> By forming multiple protruding corners on the lattice reinforcement fastener, the effect of suppressing bending deformation of the lattice reinforcement 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 any locking claws 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 fixture, but also saves materials, allowing for low-cost production. <4> The elastic force generated when the flexible bone section bends not only allows the resin 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 resin lattice bars from shifting out of position. [Brief explanation of the drawings]

[0013] [Figure 1] An explanatory diagram of a method for attaching a resin lattice bar using a lattice bar fastener according to the present invention. [Figure 2] An explanatory diagram of the dimensional relationship between the grid bar fixture and the plastic grid bar. (a) is a plan view of the grid bar fixture, (b) is an enlarged cross-sectional view of the protruding corner, and (c) is a plan view of part of the plastic grid bar. [Figure 3] Illustration of how to install plastic lattice bars [Figure 4] Illustration of how to fix the grid fixture [Figure 5] Plan view of part of the resin lattice reinforcement after fixing [Figure 6] An explanatory diagram of a lattice fixture as a comparison example without an open window, where (a) is a plan view of the lattice fixture and (b) is an enlarged cross-sectional view of the bent part of the lattice fixture. [Figure 7] This 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 installed plastic lattice bar. [Figure 8] An explanatory diagram of a conventional method for installing a plastic lattice bar using other washers DETAILED DESCRIPTION OF THE INVENTION

[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 the pit wall or side wall, and includes all concrete surfaces where concrete spalling may occur, such as ceiling surfaces.

[0016] <2> Resin lattice bars 1 and 2. The resin grid 20 is a reinforcing member with a mesh structure for covering and reinforcing the wall surface 41 of a concrete structure 40, and is formed into a grid by crossing reinforcing bars 21 made of FRP (fiber reinforced plastic), which is vinyl ester resin impregnated with high-performance continuous fibers such as carbon fiber, at predetermined 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 only the resin lattice reinforcement 20 may be used alone.

[0018] <2.2> Square The resin lattice bars 20 form quadrangular (square or rectangular) cells 22 between a plurality of reinforcing bars 21 arranged crosswise and crosswise. The grid spacing 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 surfaces 23b inside the outer surface 23a, and four inner corners 23c formed at right angles to the corners of two adjacent inner surfaces 23b.

[0020] <3> Lattice bar fixture The following description will be given with reference to Figures 1 and 2. The grid 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 fix resin grid 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 the grid fixing device The lattice bar fastener 10 includes a central portion 11, a support frame portion 12, a plurality of flexible rib portions 13, a plurality of open windows 14, and a plurality of overhanging corner portions 15. In this example, the lattice bar fixture 10 is described as having four open windows 14 and four flexible rib portions 13.

[0023] The flat plate that constitutes the lattice bar fastener 10 can be made of, for example, steel plate, stainless steel plate, aluminum plate, resin plate, FRP plate, etc., but steel plate is preferable in terms of economy and workability.

[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 the center thereof 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 prior art.

[0026] Referring to Figure 2, if the outer and inner dimensions of the support frame portion 12 are W1 and W2, and the outer and inner dimensions of the lattice frame 23 are W3 and W4, the outer dimension W1 in the vertical and horizontal directions of the support frame portion 12 is approximately the same as the outer dimension W3 of the lattice frame 23, and the inner dimension W2 in the vertical and horizontal directions of the support frame portion 12 is also approximately the same as the inner dimension W4 of the lattice frame 23. In other words, the inner and outer dimensions W1, W2 of the support frame portion 12 do not exceed the inner and outer dimensions W3, W4 of the lattice frame 23.

[0027] <3.4> Radius A plurality of flexible ribs 13 are formed radially between the central portion 11 of the lattice bar fixture 10 and the peripheral support frame portion 12. The flexible bone portion 13 is a strip-shaped portion that integrally connects the central 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 radius 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 radius 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 flexible rib portion 13 and the support frame portion 12 toward the bottom surface, a step is generated between the support frame portion 12 and the flexible rib portion 13. This step portion becomes the protruding corner portion 15.

[0031] <3.5.1> Cross-sectional shape of the outer surface of the protruding corner The protruding corner portion 15 is a protrusion that can be inscribed in the square 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 the 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 in an L-shape that is nearly a right angle.

[0032] <3.5.2> Projection angle of the protruding corner The protruding angle of the protruding corner portion 15a relative to the support frame portion 12 will be described with reference to FIG. 2(b). The protruding corner portion 15 that protrudes toward the bottom surface side of the support frame portion 12 is bent at an angle that is nearly 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. 2(a) and 2(b). When the lattice reinforcement fixture 10 is viewed in plan from the surface 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 flexible 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 about 1.5 mm. As the difference G between the inner and outer dimensions A and B becomes smaller, the bending angle of the projecting corner portion 15 relative to the support frame portion 12 or the flexion portion 13 approaches a right angle. The reason for reducing the dimensional difference G between the two inner and outer dimensions A and B is to ensure surface contact between the outer 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 reinforcement fixing device 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 slope of the outer surface 15a of the protruding corner portion 15 becomes gentler, and there is line contact between the outer 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 cannot be exerted. In the present invention, in order to restrain the protruding corner portion 15 by the squares 22, the outer peripheral surface 15a of the protruding corner portion 15 is formed to be close to 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 fixing device 10 is in use, the protruding dimension (protruding dimension) of the protruding corner portion 15 toward the bottom 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 opening windows and bending of overhanging corners The relationship between the open window 14 and the bending of the projecting corner portion 15 will be described. Referring to the comparative example of the lattice bar fixture shown in Figure 6, if one were to press the lattice bar fixture to form a recess of about 2 to 3 mm deep without providing an open window 14, it would be technically difficult to process the bent portion at an angle close to a right angle, and the bent portion would have to be bent at a gentle angle.

[0039] In the present invention, by opening a plurality of open windows 14 inside the support frame portion 12 of the lattice reinforcement fixture 10, it becomes easier to bend (press) the metal plate, 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 fixing device 10. As the anchor material 30, for example, a known core rod driving type expansion anchor can be used. The anchor material 30 is not limited to an expansion anchor, and adhesive anchors, screw anchors, etc. can also be used.

[0041] [How to install plastic lattice bars] 3 to 5, a mounting method for fixing the resin grid 20 to the wall surface 41 using the grid fixture 10 and the anchor material 30 will be described.

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

[0043] <2> Resin lattice bar covering A resin lattice reinforcement 20 is stretched over and covers the wall surface 41 of a concrete structure 40 in which a plurality of anchor materials 30 are planted (FIG. 3). At this time, the resin lattice reinforcement 20 is coated on 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 has described a form in which the anchor material 30 is fixed first, it is also possible to first position the resin lattice reinforcement 20 and the lattice reinforcement fastener 10 on the wall surface 41, and then drive the anchor material 30 into the wall surface 41 so that it passes through them and is fixed.

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

[0047] <3.1> Positioning of grid fixtures The head of the anchor material 30 is inserted through the bolt hole 11a of the lattice bar fixing device 10, and the lattice bar fixing device 10 is placed over the lattice frame 23 of the resin lattice bar 20, with the bottom surface of the support frame portion 12 abutting 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 corners 15 formed thereon in accordance with the internal 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 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 grid fixing fixtures A nut 31 is screwed onto the head of the anchor material 30 protruding from the center 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 plurality of flexible bones 13, and is then 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 reinforcement fixing device 10 to hold down the entire area of ​​each square of the lattice frame 23, thereby firmly fixing the resin lattice reinforcement 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 nuts 31 tightening the lattice bar fasteners 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 installed, the deterioration state of the wall surface 41 can be visually inspected through the open window 14 of the lattice bar fixing device 10.

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

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

[0055] Anchor materials were driven into four places on the periphery of the square resin grid 20, and grid fixtures were fixed at equal intervals. The tension member of the testing machine was hooked to the center of the resin grid 20, which was the test piece, and the tension member was pulled to apply a peeling force to the resin grid 20, thereby testing the attachment force of the resin grid 20 using 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 attachment force to the resin 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 surface 15a of the protruding corner portion 15 formed on the lattice bar fastener 10 contacts the inner surface of the inner corner portion 23c of the lattice frame 23, thereby preventing the resin lattice bars 20 from sliding sideways and increasing the gripping force between the lattice bar fastener 10 and the lattice frame 23, thereby improving load transmission efficiency.

[0058] <4.3.1> Anti-skid effect of grid fixing devices The sliding of the lattice bar fixing device shown in FIG. 6 as a comparison example will be described below. If the outer dimension of the bent portion of the lattice bar fastener is A and the inner dimension of the bent portion is B, and the plate thickness of the lattice bar fastener is, for example, 1.5 mm, the minimum dimensional difference G between the inner and outer dimensions A and B will be approximately 5 mm, and the bending angle of the bent portion 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 resin lattice bars is permitted, the following problems will arise. For example, if a resin lattice is attached to the ceiling surface of a tunnel, a downward load will be applied to the resin lattice if pieces of concrete or the like fall off. The load applied to the resin lattice bars is supported by the fixed part of the lattice bar fixing device, but if the resin lattice bars move laterally at this fixed part, the resin lattice bars themselves will undergo a large downward deflection deformation, which will become a factor in obstructing the tunnel space. Therefore, when installing plastic lattice bars on the 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, thereby 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 fixing device 10 is smaller than that at the straight portions of the support frame portion 12, increasing the engagement force between the lattice bar fixing device 10 and the lattice frame 23 and improving the load transmission efficiency.

[0062] As a means of increasing the load transmission efficiency between the lattice bar fastener 10 and the lattice frame 23 without forming the protruding corner portion 15, a method of increasing the overall plate thickness of the lattice bar fastener 10 and increasing the bending rigidity 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 protruding 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 flexible deformation of the plurality of flexible rib 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 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 Structures 41 Wall

Claims

1. A flat plate-shaped 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 and a plurality of open windows, flexible bone portions extending radially from the center to the support frame portion, and a plurality of open windows defined between the support frame portion and the pair of flexible bone portions, and is used to press and fix a plurality of resin lattice bars using anchor materials driven into the wall surface of a concrete structure, The flat plate has a size that can close a single square square formed in the resin lattice reinforcement, The flat plate has a plurality of protruding corners that are recessed at the boundary between the flexure portion and the support frame portion and protrude toward the bottom surface of the plate surface, 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. Lattice bar fixture.

2. 2. The lattice fastener according to claim 1, wherein the outer peripheral surface of the protruding corner portion is formed in an L-shape in plan view.

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

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

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

6. A spalling prevention structure for a concrete structure, comprising the lattice bar fastener according to any one of claims 1 to 5, Resin reinforcing bars are crossed at intervals to form a grid pattern, and resin lattice bars are stretched over the wall surface of the concrete structure; A plurality of lattice bar fasteners arranged on the outer surface of the resin lattice bar; and an anchor material fixed in the concrete structure with its head protruding from the wall surface, The plurality of protruding corner portions protruding on the bottom side of the lattice reinforcement fixing device are fitted into the squares of the lattice frame, positioned, and fixed with the anchor material. A structure to prevent concrete structures from falling off.

7. 7. The structure for preventing spalling of a concrete structure according to claim 6, wherein the anchor material fixes the center of the lattice bar fastener to the wall surface, and the support frame 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.

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

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