JP2011256691A - Concrete crack-inducing joint device and usage method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete crack-inducing joint device that can be easily installed at a desired position.SOLUTION: A concrete crack-inducing joint device comprises a crack-inducing joint filler (10) that has a core material, a pair of flanges extending from one end of the core material to be nearly orthogonal to the core material and in the direction of parting from each other, and a cut-off part disposed so as to cover the core material and part of the flanges and that is formed in a reverse Y-shaped form in the cross-section as a whole, and a joint filler holder (20) for fixing the crack-inducing joint filler to a prescribed position of a bar for a structure with a fastener.

Description

  The present invention relates to a joint device for inducing cracks in a wall-like concrete structure and a method of using the device. Examples of the wall-like concrete structure in which the joint device of the present invention is used include, but are not limited to, a wall portion of a watertight structure such as a purification facility, a box work, and an abutment work. .

  In order to induce a crack (crack) generated in a concrete structure to an intended location, a crack-inducing joint material is installed in the concrete structure. Conventionally, a crack-inducing joint material is installed at a desired location by binding to a structural reinforcing bar with a binding wire (number wire).

  However, since the conventional crack-inducing joint material has to be bound with a binding wire one by one, there is a problem that if the number of places where the crack-inducing joint material is installed increases, a great deal of cost and labor are required. Further, in the conventional crack-inducing joint material, it is necessary to use a binding wire as described above, and it takes time and effort to install, so it is difficult to accurately install the crack-inducing joint material at a predetermined location (for example, In addition, the crack-inducing joint material and the guide plate are not arranged in a line, and misalignment is likely to occur), and there is a problem that a crack may not be induced at an intended location.

  This invention is developed in view of such a situation, Comprising: It aims at providing the concrete crack induction joint apparatus which can be easily installed in a desired location, and the usage method of this apparatus.

  The concrete crack inducing joint device according to claim 1 is a core material, a pair of flanges each extending from one end of the core material to be away from each other so as to be substantially orthogonal to the core material, and the core A crack-inducing joint material having a water stop portion disposed so as to cover a part of the material and the flange, and formed as a whole in an inverted T-shaped cross section; It is characterized by including a joint material holder for fixing to a location.

  The concrete crack inducing joint device according to claim 2 of the present application is the device according to claim 1, wherein the crack inducing joint material is obtained by folding one plate into two at the center and folding the plate into two at an appropriate place. Each is formed by folding back.

  The concrete crack inducing joint device according to claim 3 of the present application is the device according to claim 1, wherein the joint material holder includes a main body for fixing the joint material holder itself to a structural reinforcing bar with a fastener, A joint material mounting portion into which a crack-inducing joint material is fitted, and the joint material mounting portion has an elongated plate-shaped central piece and a pair of gripping pieces respectively disposed on the opposing short sides of the central piece. The central piece is bent so as to slightly protrude toward the side where the gripping piece is located in a central axis parallel to the short side, and the gap formed by the central piece and the gripping piece It is characterized by being configured to fit a flange of a crack-inducing joint material.

  The concrete crack inducing joint device according to claim 4 of the present application further includes a guide plate attaching portion to which the guide plate is attached, and the guide plate attaching portion is a core material of the crack inducing joint material. The guide plate is fixed to the main body so that the guide plate is arranged substantially in a line.

  The method for using the concrete crack inducing joint device according to claim 5 of the present invention is the method of fitting the concrete crack inducing joint device according to claim 3 or 4 into an end of a flange of the crack inducing joint material. Attaching one or more joint material holders to a crack-inducing joint material; temporarily placing the crack-inducing joint material to which the joint material holder is attached at a joint position in a mold; and The joint material holder is slid so that the main body covers the structural reinforcing bar in the mold, and the main body is fixed to the structural reinforcing bar at a predetermined position.

  According to the concrete crack inducing joint device of the present invention, it is not necessary to bind the joint material with a binding wire as in the prior art, and it can be easily attached by sliding along the joint material. Time and effort can be greatly reduced. Further, in the joint device of the present invention, the joint material is fixed to the structural reinforcing bar with bolts using the joint material holder. The possibility of misalignment with the plate can be easily avoided, and high-precision construction can be achieved. In addition, when the crack-inducing joint material is formed of a single plate, the core material of the crack-inducing joint material spreads when the crack is generated and the degree of adhesion with the crack surface is increased, so that good water stoppage can be obtained. it can. In addition, the joint device of the present invention can be provided at low cost because of its simple structure, and is less likely to break down, and is easy to maintain. Furthermore, according to the method of using the concrete crack inducing joint device of the present invention, the concrete crack inducing joint material can be installed while maintaining good workability and high construction density.

  Next, a concrete crack inducing joint device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. The concrete crack inducing joint device according to a preferred embodiment of the present invention is roughly classified into a crack inducing joint material 10 and a joint material holder 20 for fixing the crack inducing joint material 10 to a structural reinforcing bar.

  As shown in FIG. 4A, the crack inducing joint material 10 of the concrete crack inducing joint device according to a preferred embodiment of the present invention is a core material 12 and from one end of the core material 12 to the core material 12. A pair of flanges 14 and 16 extending away from each other so as to be substantially orthogonal to each other, and a water stop portion 18 disposed so as to cover a part of the core member 12 and the flanges 14 and 16. The core material 12 and the flanges 14 and 16 as a whole form an inverted T-shaped cross section. The core material 12 and the flanges 14 and 16 are formed of a metal material (for example, a galvanized plate), and the water stop portion 18 is formed of an appropriate water stop material such as non-vulcanized butyl rubber.

  Preferably, the core member 12 and the flanges 14 and 16 are integrally formed by bending an appropriate metal material. That is, preferably, as shown in FIG. 4 (c), the crack-inducing joint material 10 is formed by folding a single plate into two at the center and folding back each of the two folded plates at appropriate points. (Folded portions become the flanges 14 and 16, and the other portions become the core material 12). In addition, the dimension of the core material 12 and the flanges 14 and 16 is suitably selected according to the installation location of the crack induction joint material 10 (refer FIG.4 (b)).

  FIG. 1 is a perspective view of the joint material holder 20, and FIG. 2 is an exploded perspective view of the joint material holder 20. A joint material holder 20 of a concrete crack inducing joint device according to a preferred embodiment of the present invention includes a main body 22.

  The main body 22 is for fixing the joint material holder 20 itself to the structural reinforcing bar, and as shown in FIGS. 1 and 2, has a substantially inverted U-shaped cross section opened downward. . A bolt hole 22a in which a female screw is cut is provided on one side surface (a leg portion of the inverted U-shaped cross section) of the main body 22, and a bolt 22b is screwed into the bolt hole 22a. The main body 22 is made of a metal material such as steel or a synthetic resin material such as plastic.

  The joint material holder 20 is also provided with a joint material attaching portion 24 for attaching the crack-inducing joint material 10. The joint material mounting portion 24 includes a long and narrow plate-like central piece 24a and a pair of gripping pieces 24b and 24c arranged on the opposing short sides of the central piece 24a. As best shown in FIG. 3B, the central piece 24a is bent so as to slightly protrude toward the side where the gripping pieces 24b and 24c are located at the central axis 24a1 parallel to the short side of the central piece 24a. It has been.

The joint material mounting portion 24 is arranged so that the grip pieces 24b and 24c are positioned on the other side surface of the main body 22 (that is, the surface opposite to the side surface where the bolt hole 22a is provided) (that is, the grip piece 24b). 24c so that the longitudinal axes x ₁ and x ₂ are substantially vertical) and are attached to the main body 22 by welding or the like (see FIG. 2).

  As clearly shown in FIG. 3B, the gripping pieces 24 b and 24 c form an acute angle α with respect to the surface A including the central piece 24 a toward the central piece 24 a. Accordingly, the crack-inducing joint material 10 is attached to the joint material holder 20 by fitting the flanges 14 and 16 of the crack-inducing joint material 10 into the gaps 24b1 and 24c1 formed by the central piece 24a and the gripping pieces 24b and 24c. Be able to. Further, as described above, since the central piece 24a is bent so as to slightly protrude toward the side where the gripping pieces 24b and 24c are located, the flanges 14 and 16 of the crack-inducing joint material 10 having an inverted T-shaped cross section are provided. When fitted in the gaps 24b1 and 24c1 of the joint material attaching portion 24, the crack-induced joint material 10 can be prevented from falling off due to the “spring effect” of the bent central piece 24a.

  In addition, Preferably, the center piece 24a and the holding pieces 24b and 24c of the joint material attachment part 24 are integrally formed. The joint material mounting portion 24 is formed of a metal material such as steel or a synthetic resin material such as plastic.

The joint material holder 20 further includes a guide plate mounting portion 26 for mounting a guide plate to be described later. The guide plate mounting portion 26 includes a long and narrow plate-like first piece 26a and a second piece 26b that are arranged to face each other with a predetermined distance d (see FIG. 3B). A gap 26c is formed between the second piece 26b. As shown in FIG. 2, the first piece 26a and the second piece 26b are joined to each other at one end. In the state where the longitudinal axis x ₃ (see FIG. 2) of the gap 26c is substantially vertical, the guide plate mounting portion 26 has a central axis 24a1 of the central piece 24a of the joint material mounting portion 24 on the side where the guide plate of the gap 26c is mounted. Is attached to one side surface (side surface provided with the bolt hole 22a) by welding or the like (see FIG. 3B). )reference). Thereby, since the core material 12 of the crack induction joint material 10 and the induction | guidance | derivation board are arrange | positioned in a substantially straight line, the possibility of the misalignment of the crack induction joint material 10 and the induction | guidance | derivation board can be avoided easily.

  The first piece 26a of the guide plate mounting portion 26 is provided with a bolt hole 26a1 in which a female screw is cut, and a butterfly bolt 26d is screwed into the bolt hole 26a1. The guide plate mounting portion 26 is formed of a metal material such as steel or a synthetic resin material such as plastic.

  The use of the concrete crack inducing joint device configured as described above will be described with reference to FIGS. First, as shown in FIG. 5 (a), by sequentially fitting the gaps 24b1 and 24c1 of the joint material mounting portion 24 of the joint material holder 20 from the end portions into the flanges 14 and 16 of the crack inducing joint material 10, Attach one or a plurality (three in FIG. 5A) of joint material holders 20 to the crack-inducing joint material 10 (as described above, the joint material mounting portion 24 serves as a kind of spring, The crack-inducing joint material 10 can be fixed without dropping). Next, the crack-inducing joint material 10 is temporarily placed at the joint position in the mold (see FIG. 5B). Next, the joint material holder 20 is slid so that the main body 22 covers the structural reinforcing bar in the mold, and the bolt 22b is tightened to fix the main body 22 (and the crack-inducing joint material 10) to the structural reinforcing bar. (See FIG. 5 (c)).

  FIG. 8 is a diagram showing a case where the crack-inducing joint material 10 is formed of a single metal plate. When a crack occurs in the concrete frame, an upward and downward force acts on the concrete frame with the core material 12 as a boundary (in FIG. 8B). The upward and downward forces act on the flange 14 of the crack-inducing joint material 10 that follows, and the force shown by the arrow in FIG. 8B acts on the root of the core material 12. Thereby, the core material 12 folded in two moves in a direction away from each other, the water stop portion 18 of the core material 12 is brought into close contact with the crack surface, and better water stoppage can be obtained.

  If the crack-inducing joint material 10 alone is insufficient to induce a crack in the concrete frame, an induction plate is installed on the back side of the structural reinforcing bar. More specifically, according to the concrete standard specification (Japan Society of Civil Engineers), in order to induce cracks in the concrete structure, the cross-sectional defect rate should be about 30% to 50%. If only the crack-induced joint material 10 is insufficient in cross-sectional defect rate, after fixing the main body 22 to the structural rebar, a guide plate for adjusting the defect rate is used as the first piece 26a of the guide plate mounting portion 26 and the first piece 26a. It is fixed by a butterfly bolt 26d sandwiched by a gap 26c between the two pieces 26b (see FIG. 5D). Thereby, a required cross-sectional defect | deletion rate can be obtained by attaching a guide plate to the guide plate attaching part 26 of the joint material holder 20. The induction plate is made of a metal material such as steel or a synthetic resin material such as plastic.

  In the concrete crack inducing joint device of the present invention, it can be used without providing a groove on the surface of the concrete frame that has been conventionally provided to promote the induction of cracks (see the left side of FIG. 6A). (Refer to FIG. 6 (a), see FIG. 6A).

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say, it is something.

  For example, in the above-described embodiment, the main body 22 of the joint material holder 20 is shown as having a U-shaped cross section, but the main body 22 is shaped into other suitable cross-sectional shapes (eg, U-shape). May be. Moreover, in the said embodiment, although the guide plate attaching part 26 is provided in the joint material holder 20, if a required cross-sectional defect | deletion rate can be ensured, the guide plate attachment to the joint material holder 20 is possible. The portion 26 may not be provided.

It is the perspective view which showed the joint material holder of the crack induction joint apparatus which concerns on preferable embodiment of this invention. It is a disassembled perspective view of the joint material holder of FIG. 3 (a) is a front view of the joint material holder of FIG. 1, FIG. 3 (b) is a view taken along line 3a-3a of FIG. 3 (a) (the main body is shown by a broken line), FIG. FIG. 3C is a view taken along line 3c-3c in FIG. 4A is a perspective view showing a crack-inducing joint material, FIG. 4B is an example of a cross-sectional view of the crack-inducing joint material, and FIG. 4C is a single plate forming a crack-inducing joint material. It is the figure which showed an example of the procedure to do. FIG. 2 is a series of diagrams illustrating the use of the crack inducing joint device of the present invention. It is a perspective view for demonstrating use of a crack induction joint apparatus. Fig.7 (a) is a top view for demonstrating use of a crack induction joint apparatus, FIG.7 (b) is the figure seen along line 7b-7b of Fig.7 (a). FIG. 8A is an enlarged view of a portion 8a in FIG. 7A, and FIG. 8B is an enlarged view showing a state in which a crack is generated in FIG. 8A.

DESCRIPTION OF SYMBOLS 10 Crack induction joint material 12 Core material 14 Flange 16 Flange 18 Water stop part 20 Joint material holder 22 Main body 22a Bolt hole 22b Fastener (bolt)
24 Joint material mounting portion 24a Central piece 24b, 24c Grip piece 26 Guide plate mounting portion 26a First piece 26b Second piece 26c Clearance 26d Butterfly bolt

Claims (5)

A concrete crack-inducing joint device,
The core material, a pair of flanges extending from the one end of the core material toward the distance away from each other so as to be substantially orthogonal to the core material, and the core material and a portion of the flange are covered. A crack-inducing joint material having a water-stop portion and formed as a whole in an inverted T-shaped cross section;
An apparatus comprising a joint material holder for fixing the crack-inducing joint material to a predetermined location of a structural reinforcing bar. The crack-inducing joint material is formed by folding a single plate into two at the center and folding the folded plate at an appropriate place, respectively. apparatus. The joint material holder is
A body for fixing the joint material holder itself to the structural rebar with fasteners;
A joint material mounting portion into which the crack-inducing joint material is fitted,
The joint material mounting portion has an elongated plate-shaped central piece and a pair of gripping pieces respectively disposed on the short sides facing the central piece, and the central piece is a central axis parallel to the short side , And is bent so as to slightly protrude to the side where the gripping piece is located, and is configured to fit the flange of the crack-inducing joint material into a gap formed by the central piece and the gripping piece. The apparatus according to claim 1, wherein: A guide plate mounting portion to which the guide plate is attached is further provided, and the guide plate mounting portion is fixed to the main body so that the core material of the crack-inducing joint material and the guide plate are arranged substantially in line. A device according to claim 3. A method of using the concrete crack inducing joint device according to claim 3 or 4,
Attaching one or more joint material holders to the crack-inducing joint material by fitting the joint material holder from an end portion into a flange of the crack-inducing joint material; and
Temporarily placing the crack-inducing joint material to which the joint material holder is attached at a joint position in a mold,
Sliding the joint material holder so that the main body covers the structural rebar in the mold, and fixing the main body to the structural rebar at a predetermined location;
A method comprising the steps of:

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