JP6701707B2 - Concrete reinforcement and concrete reinforcement structure - Google Patents

Description

The present invention relates to a concrete reinforcing tool and a concrete reinforcing structure mainly used for a reinforced concrete structure, particularly a reinforced concrete structure such as a wall, a beam or a column having a large cross-sectional dimension.

  In constructing a structure with reinforced concrete (hereinafter referred to as RC), for example, in a wall structure, in addition to a main bar and a distribution bar that is generally arranged orthogonally to the main bar, a shear reinforcement bar for supporting diagonal tensile stress. Are arranged along the direction orthogonal to the wall surface. Further, in a pillar structure such as a pier, in order to restrain concrete, prevent buckling of the main bar, or enhance the action thereof, an intermediate band rebar is arranged in a band rebar arranged so as to surround the main bar.

  The main function of these shear reinforcements, concrete restraints, and reinforcing bars for preventing buckling of main bars (hereinafter called restraint bars) is shear reinforcement depending on the location where they are placed, or concrete restraints and buckling of main bars. Although there are differences such as prevention or having both of these functions, they all have the common point of increasing the toughness of the RC structure and play a role of increasing the strength of the RC structure by resisting bending moments. The role of concrete reinforcement is different from that of the main reinforcement.

  Shear reinforcements and restraints are, for example, in the reinforcement work when constructing a wall structure, the main reinforcements are erected in the vicinity of each wall while considering the cover thickness of concrete, and are orthogonal to these main reinforcements. Thus, the shear reinforcing bars are arranged in the direction perpendicular to the wall surface by hooking hooks provided at the ends of the shear reinforcing bars at the intersections of the main reinforcing bars and the distributing bars. Further, in the column structure, the hooks provided at the end portions of the intermediate strip reinforcing bars are hooked at the positions where the reinforcing bars are wound so as to surround the main reinforcing bars and have a positional relationship of front and back sides. Arrange the intermediate bars in the radial direction.

  However, in order to improve the seismic performance of RC, it is generally necessary to provide a sharp-angled hook at the terminal end of the shear reinforcement bar or restraint bar. The entire rebar assembly procedure, including the above, tends to be complicated, and the rebar construction requires a great deal of time.

  Under such circumstances, recently, a shear reinforcing bar having a fixing plate or a locking plate at its end has been developed and put into practical use. Particularly, the fixing plate or the locking plate disclosed in Patent Document 1 capable of being mounted on site is disclosed. According to the reinforcing reinforcing bar, since the reinforcing bar can be arranged after the main bar, the reinforcing bar, or the stirrup is pre-assembled, it is possible to expect some improvement in the construction efficiency at the site.

JP, 2004-249643, A

"Expansion of applicability of plate anchoring type shear reinforcing bar Head-bar" (Taisei Construction Technology Center Bulletin No. 45 (2012))

  However, the above-mentioned shear reinforcing bar provided with the fixing plate and the locking plate at the end is more effective in shear reinforcing performance, concrete restraint, or buckling prevention of the main rebar than the conventional shear reinforcing bar provided with the acute angle hook. However, if the RC structure is required to have a high toughness, it is necessary to arrange the RC structure at a high density like the conventional shear reinforcing bar.

  Therefore, it takes time to arrange the shear reinforcement and restraint bars in the reinforcement work, and in the concrete work, the gap between the shear reinforcement and the restraint bars is prevented so that free fall or one-sided pressing that may cause material separation will not occur. In order to reduce the load on concrete, it is necessary to repeat the work of lowering the chute for pouring, and then pulling it up once the concrete has been added. Traditional problems such as decline have remained unsolved.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a concrete reinforcing tool and a concrete reinforcing structure capable of efficiently performing a reinforcing bar work and a concrete work.

In order to achieve the above object, the concrete reinforcing tool according to the present invention is arranged in the vicinity of a rod and a reinforcing bar which is provided at each end of the rod and located at an area where the rod is joined, as described in claim 1. In a concrete reinforcing tool consisting of a reinforcing plate,
A concrete reinforcing tool in which the rod is composed of a PC steel rod, a male screw is formed on each end of the PC steel rod, and a female screw to be screwed into the male screw is formed on the reinforcing plate. The plate is configured as a fixing plate in which a load for restraining the protrusion of concrete and a load for shear-reinforcing the concrete directly act on the concrete .

  Further, the concrete reinforcing tool according to the present invention is configured such that the PC steel rod is made of type D and has an outer diameter of 17 mm or more.

Further, the concrete reinforcing tool according to the present invention is configured by quenching S45C in the reinforcing plate.

Further, as described in claim 4 , the concrete reinforcing structure according to the present invention is such that the concrete reinforcing tool according to any one of claims 1 to 3 is embedded in concrete, and a main bar, a distribution bar, and a belt are provided. A concrete reinforcing structure in which reinforcements and other reinforcements arranged with a predetermined covering thickness are embedded in the concrete, wherein the rods have their respective ends located on the front side and the rear side of the reinforcements. The reinforcing plates are arranged so as to project from the open spaces of the reinforcing bars, and the reinforcing plates are attached to the respective end portions.
Further, in the concrete reinforcing structure according to the present invention, the reinforcing plate is installed such that concrete is interposed between the back surface of the reinforcing plate and the reinforcing bar.

In order to solve the problems described in the solution problem section, it is necessary to increase the tensile resistance of each of the shear reinforcing bar and the restraining bar, but it is assumed that the high strength reinforcing bar and the fixing plate or the locking plate are optimally combined. However, the total tensile resistance is only about 400 to 500 N/mm ² at the yield point (Non-Patent Document 1).

  Each invention of the present application has been made in view of the limitation of improvement in tensile resistance as long as a conventionally known reinforcing bar is used. In the concrete reinforcing tool according to the first invention, the rod is a PC steel rod. And a male screw is formed on each end of the PC steel rod, and a female screw screwed to the male screw is formed on the reinforcing plate.

  By doing so, it is possible to perform shear reinforcement with a PC steel rod having high tensile resistance, and to prevent concrete restraint or buckling of reinforcing bars, particularly main reinforcing bars. It is possible to significantly reduce the number of lines to be arranged rather than the lines.

  As a result, the work of reinforcing bars is reduced in the construction of reinforcing bars, and the work of raising and lowering chutes for concrete injection is simplified in the construction of concrete, and shear reinforcement bars and restraint bars are arranged in high density. Since the narrow space generated by this is eliminated, the filling property of concrete is also improved.

  Further, since the joining form of the rod and the reinforcing plate is screwed, even if the reinforcing bar is placed in advance in the concrete placing space, the rod is inserted from the space of the reinforcing rod to perform the concrete placing. It is sufficient to place the rod in the space and then screw the reinforcing plate to the end of the rod.

  Therefore, the work of installing the concrete reinforcing tool according to the present invention can be performed in a state of being completely separated from the reinforcing work, and there is no influence on the reinforcing bar work.

Although the reinforcing plate is installed in the form in which its back surface is in contact with the reinforcing bar, and in the case where it is installed in the form in which some concrete is interposed between the rear surface and the reinforcing bar, the installation form is included. In any case, for the reinforcing bar, the load that constrains the buckling or the protrusion acts directly or through concrete, and for the concrete, the load that constrains the protrusion or shear reinforcement The load to be applied acts directly or through the rebar, and in the sense that the applied load is due to the tensile load (pull-out load) transmitted from the rod, it can be rephrased as a fixing plate, or directly on the rebar or on concrete. Although it can be rephrased as a locking plate in the sense that it is locked via, it is collectively referred to as a reinforcing plate in this specification. The reinforcing plate in the first aspect of the invention is configured as a fixing plate in which a load for restraining the protrusion of concrete and a load for shear-reinforcing concrete act directly on the concrete.

As the PC steel bar, those specified in JIS G3109, such as C type (proof strength is 1080N/mm ² or more, tensile strength is 1230N/mm ² or more) can be used, but especially JIS G3137 (small diameter variant) It is desirable to use class D (proof strength 1275 N/mm ² or more, tensile strength 1420 N/mm ² or more) stipulated for PC steel bar and to have an outer diameter of 17 mm or more.

Once the specifications described above with PC steel bar, SD345 (yield strength as a conventional shear reinforcement and bound muscles are commonly used ^{345N / mm 2 ~440N / mm 2} , a tensile strength of 490 N / mm ² or more ), the yield strength is 3.7 times and the tensile strength is 2.9 times. Therefore, if the cross-sectional area per piece is the same, shear reinforcement, concrete restraint, or buckling prevention of reinforcing bars, especially main reinforcing bars It is possible to reduce the number of required arrangements to about 1/3 to 1/4 of the conventional one.

  The reinforcing plate may be appropriately configured so as to have a strength commensurate with the strength of the PC steel rod, but as described above, the PC configured by using the class D and having an outer diameter of 17 mm or more is used. When a steel rod is used, it is desirable that S45C is hardened.

The procedure for installing the concrete reinforcing tool according to the first invention in the concrete placing space is arbitrary, and while assembling the main bar, the force distribution bar, or the band bar, the bar reinforcement work is performed concurrently with the bar arrangement work. Although it may be installed, a typical example is to follow an installation method consisting of the following procedures (hereinafter referred to as a method for installing a concrete reinforcing tool according to the reference invention ). That is,
(a) Main bars, distribution bars, strips and other reinforcing bars to be arranged with a predetermined cover thickness are pre-assembled in the concrete placing space.
(b) Of the end portions of the rod constituting the concrete reinforcing tool according to the first aspect of the invention, the end portion to which the reinforcing plate is not attached is defined as one end portion, and the one end portion is the space for the reinforcing bar described above. Insert from.
(c) Push the rod so that it is placed in the concrete pouring space.
(d) One end of the rod is made to protrude from the open space of the reinforcing bar located on the back side of the above-mentioned reinforcing bar when the insertion side of the rod is the front side, and the reinforcing plate is attached to the one end. .
This makes it possible to perform the work of installing the concrete reinforcing tool according to the first aspect of the invention in a state completely separated from the work of arranging, and there is no influence on the reinforcing bar work.

  Here, it is optional whether the rod is inserted and pushed while the reinforcing plate is attached to the other end of the rod, but it is necessary to attach the reinforcing plate to the other end of the rod before inserting the rod. In this case, since it is sufficient to push the rod in until the reinforcing plate comes into contact with the reinforcing bar, it is not necessary to pay attention to the timing when the pushing of the rod is finished, and the reinforcing plate is temporarily placed horizontally in an appropriate place, for example. By rotating the rod, the reinforcing plate can be attached to the other end of the rod, which facilitates the installation work of the concrete reinforcing tool according to the first aspect of the invention.

  Further, when installing the concrete reinforcing tool according to the first aspect of the invention, as described above, it is not always necessary to bring the back surface of each reinforcing plate into contact with the front reinforcing bar or the rear reinforcing bar, and the reinforcing plate and the reinforcing bar Although concrete may intervene between the rod and the rod, one end of the rod, that is, the reinforcing plate attached to the tip side is abutted on the reinforcing bar on the back side, and the other end, that is, the base end side. If the reinforcing plates are attached so that the attached reinforcing plates come into contact with the reinforcing bars on the front side, it is possible to surely exhibit the buckling prevention effect of the reinforcing bars, especially the main reinforcing bars. ..

  In addition, when performing the above-mentioned attachment, it is not necessary to rotate both the two reinforcing plates, and it is sufficient to rotate only one of the reinforcing plates, for example, the reinforcing plate on the tip side.

  As a concrete reinforcing structure using the concrete reinforcing tool according to the first aspect of the present invention, the concrete reinforcing tool is embedded in concrete, and main bars, distribution bars, stirrups and other reinforcing bars arranged with a predetermined covering thickness are provided. A concrete reinforced structure embedded in concrete, wherein the above-mentioned rods are arranged such that each end of the rod protrudes from the open space of the reinforcing bar located on the front side and the rear side of the reinforcing bar. A typical example is a structure in which each reinforcing plate is attached to each end (hereinafter referred to as a concrete reinforcing structure according to the third invention).

The assembly perspective view which showed the concrete reinforcement tool 1 which concerns on this embodiment. It is the figure which showed the concrete reinforcement structure 21 which concerns on this embodiment, (a) is a vertical cross-sectional view, (b) is the arrow line view seen from the AA line. The construction procedure figure showing the installation method of concrete reinforcement 1 concerning this embodiment. The horizontal sectional view showing concrete reinforcement structure 41 concerning a modification.

  Embodiments of a concrete reinforcing tool, a method of installing the same, and a concrete reinforcing structure according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an assembled perspective view showing a concrete reinforcing tool according to the present embodiment. As shown in the figure, the concrete reinforcing tool 1 according to the present embodiment includes a rod 2 and disc-shaped reinforcing plates 3 and 3 provided at each end of the rod 2.

The rod 2 is a PC steel rod of Class D (proof strength 1275 N/mm ² or more, tensile strength 1420 N/mm ² or more) specified in JIS G3137 (small diameter deformed PC steel rod) Is 17 mm or more, and the reinforcing plate 3 is formed by quenching S45C so as to have a strength commensurate with the strength of the PC steel rod.

  Here, male screws 4 and 4 are formed at each end of the rod 2, and female screws 5 to be screwed into the male screws are formed in each reinforcing plate 3, respectively. It can be screwed to each end of 2.

  The concrete reinforcing tool 1 has, for example, a configuration in which the outer diameter of the rod 2 is 19 mm, the outer diameter of the reinforcing plate 3 is 90 mm, and the thickness is 20 mm, or the outer diameter of the rod 2 is 23 mm, the outer diameter of the reinforcing plate 3 is 90 mm, and the thickness is 20 mm. It is possible to adopt a configuration in which is 24 mm. The length of the rod 2 may be appropriately determined according to the cross-sectional size of the concrete frame to be installed.

  In addition, in the conventional concrete reinforcement tool, it is necessary to secure the length of the female screw by making the fixing plate and the locking plate sufficiently thick so that the tensile material will not be broken by the female screw before the base material is broken. However, according to the present embodiment, since the reinforcing plate 3 is configured by quenching S45C as described above, the brittleness of the reinforcing plate 3, and thus the female screw 5 formed on the reinforcing plate is improved. Thus, even if the length of the female screw 5 is not excessively large, it is possible to prevent breakage of the female screw in advance, and the thickness of the reinforcing plate 3 can be suppressed as described above.

  FIG. 2 shows an embodiment in which the concrete reinforcing structure according to the present invention is applied to an RC wall structure, for example, a wall of a box culvert, and the concrete reinforcing structure 21 according to the embodiment has a main bar 23 and The distribution bars 24 on the outer side thereof and orthogonal to the main bars are embedded in the concrete poured into the concrete placing space 22 so as to have a predetermined covering thickness on both sides of the wall surface, and The rear surfaces of the reinforcing plates 3 and 3 are preferably arranged on the force distribution bars 24 and 24, respectively, so that the reinforcing plates 3 and 3 are arranged in the vicinity of the force distribution bars 24 and 24 located at the joint portion with the rod 2. The concrete reinforcing tool is embedded in concrete so as to be directly engaged with the force distributing muscles in abutting manner.

  Here, each end of the rod 2 is located on the front side (for convenience, the right side in the figure is the front) of the distribution muscles 24 and 24 and on the rear side. It is arranged so as to project from the open space of the force bar 24 (on the left side in the figure), and the reinforcing plates 3 are attached to the respective end portions.

  In constructing the concrete reinforcing structure 21, in order to install the concrete reinforcing tool 1 in the concrete placing space 22, first, the main reinforcement 23 and the force distribution reinforcement 24, which should be arranged with a predetermined cover thickness, are set in the concrete placing space. Assemble 22 in advance.

  On the other hand, before installing the concrete reinforcing tool 1 in the concrete placing space 22, the male screw 4 formed on the proximal end side as the other end of the rod 2 is replaced with the female screw 5 of the reinforcing plate 3. The reinforcing plate 3 is preliminarily attached to the base end side of the rod by screwing.

  In this work, the reinforcing plate 3 is temporarily placed horizontally at a place different from the place where the concrete reinforcing structure 21 is constructed, and the rod 2 is vertically held right above the reinforcing plate 3 in such a state, and then the male screw of the rod is held. 4 may be screwed into the female screw 5 of the reinforcing plate 3.

  Next, as shown in FIG. 3(a), of the end portions of the rod 2, the tip as one end portion to which the reinforcing plate 3 is not attached is the main bar 23 located on the front side (right side in the figure). And, it is inserted from the open space of the distribution muscle 24.

  Next, the rod 2 is pushed so that it is placed in the concrete pouring space 22, and then the tip of the rod 2 is located on the back side (left side in the figure) as shown in FIG. It is made to project from the open space of 23 and the distribution muscle 24.

  Next, the reinforcing plate 3 is attached to the tip of the rod 2 by screwing the female screw 5 of the reinforcing plate 3 into the male screw 4 formed at the tip of the rod 2.

  When attaching the reinforcing plate 3 to the tip of the rod 2, the reinforcing plate 3 is brought into contact with the rear force distribution muscle 24, and the reinforcing plate 3 previously attached to the base end side of the rod 2 is attached to the front side. The reinforcing plate 3 is screwed into the male screw 4 formed at the tip of the rod 2 until it abuts against the force bar 24.

  After the concrete reinforcing tool 1 is installed in this way, concrete is poured into the concrete placing space 22 to construct the concrete reinforcing structure 21.

  As described above, according to the concrete reinforcing tool 1, the method for installing the same, and the concrete reinforcing structure 21 according to the present embodiment, since the rod 2 is made of the PC steel rod having high tensile resistance, shear reinforcement and concrete restraint are performed. Alternatively, in order to prevent buckling of reinforcing bars, especially main reinforcing bars, it is possible to significantly reduce the number of bars to be arranged as compared with the conventional shear reinforcing bars and restraining bars.

  As a result, the work of reinforcing bars is reduced in the construction of reinforcing bars, and the work of raising and lowering chutes for concrete injection is simplified in the construction of concrete, and shear reinforcement bars and restraint bars are arranged in high density. Since the narrow space generated by this is eliminated, the fillability of concrete is also improved.

  Further, according to the concrete reinforcing tool 1, the method for installing the same, and the concrete reinforcing structure 21 according to the present embodiment, since the joining form between the rod 2 and the reinforcing plate 3 is screwed, the concrete placing space 22 is preceded by the reinforcing bar. Even if they are arranged, it suffices to insert the rod from the open space of the reinforcing bar, arrange the rod in the concrete placing space, and then screw the reinforcing plate to the end of the rod.

  Therefore, the installation work of the concrete reinforcing tool 1 can be performed in a state completely separated from the reinforcing work, and there is no influence on the reinforcing bar work.

Further, according to the concrete reinforcing tool 1 of the present embodiment, since the rod 2 which is a PC steel rod is configured to use the type D and has an outer diameter of 17 mm or more, the conventional shear reinforcing bar and restraint 3.7 times more proof strength and 2.9 times more tensile strength than SD345 (proof strength is 345N/mm ^{2 to} 440N/mm ² , tensile strength is 490N/mm ² or more) that is generally used as a muscle. Therefore, if the cross-sectional area per piece is the same, reduce the number of arrangements necessary for shear reinforcement, concrete restraint, or buckling prevention of reinforcing bars, especially main reinforcing bars to about 1/3 to 1/4 of the conventional one. Is possible.

  Further, according to the method for installing the concrete reinforcing tool according to the present embodiment, the reinforcing plate 3 is attached to the base end side of the rod 2 before the step of inserting the rod 2, so that the pushing of the rod 2 is completed. It becomes unnecessary to pay attention to the timing, and the installation work of the concrete reinforcing tool 1 becomes easy.

  Further, according to the method for installing the concrete reinforcing tool according to the present embodiment, the reinforcing plate 3 attached to the tip of the rod 2 is attached to the rear force distribution muscle 24, and the reinforcing plate 3 attached to the proximal end is attached to the front side. Since the reinforcing plates 3 and 3 are attached so as to be respectively brought into contact with the force distribution muscles 24 on the side, it is possible to surely exert the buckling prevention action on the force distribution muscles 24 and the main muscles 23. Become.

  In the present embodiment, the rod of the concrete reinforcing tool according to the present invention is configured by a PC steel rod having a mechanical property of type D and an outer diameter of 17 mm or more, but instead of this, the mechanical property is changed. It may be A, B or C type or may have an outer diameter of less than 17 mm.

  Further, in the present embodiment, before the step of inserting the rod 2, the reinforcing plate 3 is preliminarily attached to the base end side of the rod 2, but it is also possible to arrange only the rod 2 in advance.

  Further, in the present embodiment, the reinforcing plate 3 attached to the tip of the rod 2 abuts on the rear force distribution muscle 24, and the reinforcing plate 3 attached to the proximal end abuts on the front energy distribution muscle 24. Although the reinforcing plates 3 and 3 are attached as described above, the concrete is interposed between the reinforcing plate 3 and the force distribution bar 24, in other words, the reinforcing plate 3 distributes force through the concrete. It does not matter if it is indirectly locked to the muscle 24.

  Further, although the present embodiment has been described as an example in which the concrete reinforcing structure according to the present invention is applied to the RC wall structure, the concrete reinforcing structure of the present invention is an arbitrary RC structure such as an RC column structure or an RC beam structure. Applicable to the body.

  FIG. 4 shows a modified example in which the concrete reinforcing structure according to the present invention is applied to a bridge pier as an RC column structure, and the concrete reinforcing structure 41 according to the modified example is wound around a main bar 42 and its surroundings. The swirl belt 43 to be turned is embedded in the concrete placed in the concrete placing space 44 so as to have a predetermined cover thickness, and the reinforcing plates 3 and 3 of the concrete reinforcing tool 1 engage with the rod 2. So as to be arranged in the vicinity of the stirrups 43 located at, preferably, the back surfaces of the reinforcing plates 3 and 3 are directly engaged with the stirrups so as to be in contact with the stirrups 43, respectively. The concrete reinforcing tool 1 according to the modified example functions as an alternative to the conventional intermediate strip rebar.

1 Concrete Reinforcing Tool 2 Rod 3 Reinforcing Plate 4 Male Screw 5 Female Screw 21, 41 Concrete Reinforcing Structure 22 Concrete Placing Space 23, 42 Main Bar 24 Main Bar 24 Force Bar 43 Band

Claims (5)

In a concrete reinforcing tool comprising a rod and a reinforcing plate which is provided at each end of the rod and is arranged in the vicinity of a reinforcing bar located at a mating portion with the rod,
A concrete reinforcing tool in which the rod is made of a PC steel rod, a male screw is formed at each end of the PC steel rod, and a female screw to be screwed into the male screw is formed on the reinforcing plate. A concrete reinforcing tool, wherein the plate is configured as a fixing plate in which a load for restraining the protrusion of concrete and a load for shear-reinforcing the concrete directly act on the concrete. The concrete reinforcing tool according to claim 1, wherein the PC steel rod is made of type D and has an outer diameter of 17 mm or more. The concrete reinforcing tool according to claim 2, wherein the reinforcing plate is formed by quenching S45C. The concrete reinforcing tool according to any one of claims 1 to 3 is embedded in concrete, and main bars, distribution bars, stirrups, and other reinforcing bars arranged with a predetermined covering thickness are embedded in the concrete. In the concrete reinforcing structure, the rod is arranged so that each end of the rod protrudes from the open space of the reinforcing bar located on the front side and the rear side of the reinforcing bar, and at each end of the reinforcing bar. A concrete reinforcing structure, characterized in that each of the reinforcing plates is attached. The concrete reinforcing structure according to claim 4, wherein the reinforcing plate is installed such that concrete is interposed between the back surface of the reinforcing plate and the reinforcing bar.

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