JP3949521B2 - Reinforcing bar joint and rebar joining method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reinforcing bar joint for joining reinforcing bars used for reinforcing materials of various concrete structures, and a reinforcing bar joining method using the same.
[0002]
[Prior art]
Conventionally, reinforced concrete structures (RC) or steel reinforced concrete structures (SRC) are frequently used in structures in the field of construction and civil engineering such as buildings and bridges. In parts such as columns and beams in such a structure, shear reinforcement bars (strip bars and stirrup bars) at predetermined intervals in the longitudinal direction so as to surround a plurality of main bars (column bars and beam bars) juxtaposed in a rectangular tube shape. Is placed. In these shear reinforcement bars, as a means for forming a closed shape, generally, the end part of a reinforcing bar is bent into a 135 ° hook shape. However, when the extra length of the hook part hinders the arrangement of the reinforcing bar, the end part of the reinforcing bar is mechanically joined by flare groove welding or a cylindrical reinforcing bar joint. In this case, instead of joining the ends of the reinforcing bars on the same axis as the main reinforcing bars for reasons such as workability, the reinforcing bars are overlapped with a predetermined length in any method. Be joined.
[0003]
As a conventional example of a reinforced joint for the lap joint type as described above, there is a wedge press-fit type proposed by the present applicant (Japanese Utility Model Publication No. 58-53880). This rebar joint has advantages in that the quality of the joint is stable and the work is simple as compared to welding which is easily affected by weather conditions and the skill of the operator. However, since a hydraulic pump is used for the press-fitting of the wedge, there is a problem that when the reinforcing bar has a large diameter, the press-fitting device becomes large and the workability is inevitably lowered.
[0004]
Further, as a reinforcing bar joint of a different type, it is also proposed to apply a grout filling type reinforcing bar joint widely used for joining main bars to a lap joint (Japanese Patent Laid-Open No. 63-55245). . That is, in this type of rebar joint, the inner hollow portion of the joint body that receives the two rebars is formed in an elliptical cross section, and the ends of the rebars are inserted through the openings at both ends, respectively. Reinforcing bars in the joint body. Then, a grout material such as high-strength mortar or synthetic resin is injected without gap from the injection hole provided in the peripheral wall into the internal space, and the reinforcing bars are joined by solidification. In this case, the load transmission between the reinforcing bars in the joined state mainly depends on the shear resistance of the grout material that has entered between the nodes of the reinforcing bars. Further, in order to enhance the adhesion between the joint body and the grout material, it is usual to provide a plurality of annular protrusions or arc-shaped protrusions such as continuous spiral protrusions on the inner wall surface of the joint body.
[0005]
[Problems to be solved by the invention]
The latter grout filling type reinforcing bar joint does not require a special device in the joining operation, has an advantage that the operation is simple, and it is relatively easy to cope with a large diameter reinforcing bar. However, since it is a joint structure that relies on a grout material that is inherently inferior in mechanical strength compared to metal materials, in order to obtain sufficient joint strength, the length of the anchoring portion must be increased compared to other mechanical joints. It is necessary to secure. For this reason, the total length of the joint body is inevitably long, and there is a problem that it is difficult to reduce the weight and size.
[0006]
Accordingly, the present inventors have come up with the present invention as a result of intensive studies on such a grout-filled type of reinforcing bar joint. That is, an object of the present invention is to provide a grout-filled reinforcing bar joint that can be reduced in weight and size.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, the ends of the reinforcing bars are inserted in opposite directions from the openings on both ends into a cylindrical joint body in which arc-shaped protrusions are formed on the inner surface of the peripheral wall. In the rebar joint in which the reinforcing bars are overlapped in the inner space, and these rebars are joined through the grout material filled in the inner space from the injection hole formed in the peripheral wall, the joint body has its inner space Are provided with a wall-like portion separating the superposed reinforcing bars from each other by at least a part of the overlapping portion in the longitudinal direction , and the inner hollow portion of the joint body is substantially divided into two by the wall-like portion. Insert the end of one reinforcing bar into the divided inner space from the opening on one end side toward the other end, and the end of the other reinforcing bar toward the one end side from the opening on the other end side Insert the ends of the reinforcing bars between the walls It is characterized by being arranged to joining the superposed state.
[0008]
According to this configuration, Rutotomoni provided wall-shaped portion which separates at least a portion of the overlapping portion in the longitudinal direction from each other rebar each other fit state overlaid on the hollow portion of the joint main body, the inner space of the joint body by the wall-like portion The part is substantially divided into two, and the end of one rebar is inserted from the opening on one end side to the other end side in each divided inner space, and the end of the other rebar is By inserting from the opening on the other end side toward the one end side and arranging the end portions of the reinforcing bars in an overlapping state with the wall-shaped portion interposed therebetween, the binding force of the grout material is greatly improved. That is, in the conventional example in which the inner space of the joint body that receives the reinforcing bars is a single space, the injected grout material spreads between and around the two reinforcing bars and is solidified as a single piece. And when a load in the pulling direction is applied to the reinforcing bars, especially the grout material between the two reinforcing bars is subject to stress in the opposite direction by the reinforcing bars at the same time, so it is easy to break even with a load that is not so large it is conceivable that. On the other hand, in the reinforcing bar joint of the present invention, each grout material covering the periphery of each reinforcing bar is made of a material such as a steel material with high mechanical strength that forms the joint body on the entire circumference of the portion where the wall-like portion exists. It is surrounded by. For this reason, each grout material is not substantially affected by the behavior of the other reinforcing bar described above, and is restrained only by the joint body, so that a strong restraining force can be obtained for the reinforcing bar. Therefore, in the reinforcing bar joint of the present invention in which the effect of filling the grout material is effectively exhibited, it is possible to shorten the length of the fixing portion between the reinforcing bars. Furthermore, since the presence of the wall-like portion greatly contributes to the improvement of the rigidity of the joint body, the thickness of the peripheral wall of the joint body can be made thinner than the conventional one. Thereby, the weight reduction and size reduction of a coupling main body are implement | achieved.
[0009]
Furthermore, in the reinforcing bar joint of the present invention, it is preferable that the wall-like portion is provided at at least both end portions of the joint body. In other words, in the conventional grout-filled reinforcing bar joint where there is no wall-like part in the inner space, when the reinforcing bars are pulled with an excessive load, cracks occur first in the grout material near the opening of the joint body, It gradually expands inward. As a result, the grout material loses the binding force, which is the original function, and the reinforcing bars are pulled out. On the other hand, in the case where the wall-like portion is provided at both end portions of the joint body, the grout material in the vicinity of the opening portion is constrained on the entire periphery, and has a structure in which cracks do not easily occur. Therefore, when the wall-like portion is provided only on a part of the joint body, both end portions are more effective than the intermediate portion of the joint body, which is convenient for shortening the joint body.
[0010]
Further, the wall-shaped portion may be divided at a part in the longitudinal direction, and the grout material injection hole may be communicated with the divided portion. In this case, the grout material injected from the outer peripheral surface side of the joint main body is smoothly distributed to the respective inner space portions divided by the wall-shaped portion in the divided portion. For this reason, it is not necessary to provide an injection hole for each of the inner space portions, and workability deterioration due to the provision of the wall-shaped portion does not occur.
[0011]
Further, in the present invention, the following configuration can also be adopted as a suitable means. That is, when a grout material channel that is continuous in the longitudinal direction is provided on the injection hole side of the wall-like portion, the grout material filling operation becomes smoother and more reliable. Further, when the arc-shaped protrusion is formed so that the injection hole side is lower than the protruding height on the opposite side in the radial direction, it is convenient for reducing the concrete covering thickness. And all the reinforcement joints by these structures can be further reduced in weight and size in combination with a grout material containing appropriate reinforcing fibers such as steel fibers. By using such a grout material, it is possible to greatly improve the rebar joining operation.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The rebar joint according to the present invention is not particularly limited in its place of use, and can be widely applied when joining various rebars in a lap joint state. Therefore, the structure can be either newly established or existing. Generally, it is used suitably for the joining of the shear reinforcement in a concrete structure. In this case, in addition to applying it to the end of one rebar that is bent in an annular shape and making it a closed type, depending on the size of the column or beam, a single shear is formed by a plurality of rebar joints and a plurality of rebars. It can also be a reinforcing bar.
[0013]
In the present invention, as a method of injecting the grout material into the joint body, for example, a funnel may be applied to the injection hole and injected by natural fall, or may be press-fitted with an appropriate injection gun. In any case, solid filling is important, and therefore, it is desirable to provide a flow path of the grout material continuous in the longitudinal direction in the inner space of the joint body that receives the reinforcing bars. As a method of forming such a flow path, for example, as will be described later, for example, the cross-sectional shape of the insertion portion of the reinforcing bar separated by the wall-shaped portion is not circular, but a part thereof protrudes outward. It is convenient to have a shape and to connect the grout material injection hole in the vicinity of the flow path. It should be noted that an exhaust hole for facilitating the entry of the grout material may be provided on the outer peripheral surface of the joint body and used for confirming the filling state of the grout material, and it is of course possible to provide a plurality of injection holes.
[0014]
Furthermore, the grout material applicable to the reinforcing bar joint of the present invention may be a general grout material such as mortar or synthetic resin as it is, but it is mixed with reinforcing fibers having excellent tensile strength such as steel fibers. Is particularly suitable in combination with the joint body provided with a wall-like part. Examples of reinforcing fibers other than steel fibers include carbon fibers, aliphatic or aromatic polyamide fibers, polyolefin fibers, glass fibers, and ceramic fibers. The blending of such reinforcing fibers has the effect of improving the resistance of the grout material to shearing, so that the grout material containing the reinforcing fibers is coupled with the restraining effect by the wall-shaped portion inside the joint body, and the reinforcing bars are pulled out. Greatly contributes to strength improvement. In the present invention, considering the dispersibility in the grout material and the fluidity of the kneaded material, that is, the grout material kneading operation and the filling into the voids inside the joint body, it is desirable to be formed into a short fiber shape. . Among them, short fiber-like steel fibers are preferable from the viewpoints of price and blending effect, and those produced by various production methods such as cut wire fibers, shear fibers, melt extraction fibers, cutting fibers and the like can be applied.
[0015]
The effect when the reinforcing fibers are mixed in the grout material will be described by taking a combination of steel fibers and a mortar grout material as an example. First, when comparing the mechanical properties of the raw materials themselves, the compression strength of a normal grout material in a solidified state is about 1/2 to 1/10 that of a steel material, and its shear strength is about 1/10 of the compression strength. is there. On the other hand, the steel material has the same compressive strength and tensile strength, the shear strength is only about 1 / √3, and has a strength 10 times or more that of the grout material. In addition, as a characteristic of the grout material, if a crack is caused by an external force, the strength is lowered early, but the steel material has higher mechanical strength than the grout material, and does not cause a sudden drop in strength. It has a deteriorating property. And in the grout material in which the steel fibers are mixed, the steel fibers are oriented in all directions and resist the external force. For this reason, the grout material has increased compressive strength and shear strength as compared with those not containing steel fibers, and even if cracks occur, it becomes ductile fracture due to the presence of steel fibers. Such a grout material is filled between the joint body and the reinforcing bar, and the stress transmission between them is mainly a shearing force, and the steel fibers dispersed in the grout material work effectively against it. This reinforcing effect is the same for other reinforcing fibers, although to a different extent. If such a grout material is used, the length of the fixing portion of the reinforcing bar, that is, the total length of the joint body can be further shortened.
[0016]
【Example】
Embodiments of the present invention will be described below based on the drawings. 1 to 3 are a front view, a plan view, and a left side view, respectively, relating to an embodiment of a reinforcing bar joint according to the present invention. In the illustrated reinforcing bar joint 1, the joint body 2 is a cylindrical body whose basic shape is substantially elliptical in cross section (oblong shape) as is apparent from FIG. 3 and the like, and is formed by casting. Both end portions of the joint body 2 are formed to be somewhat larger than the intermediate portion in the radial direction, and two insertion ports 3 are provided in the bulging portion 21 respectively. As described above, these bulged portions 21 take into account the reinforcement of the end portions that play a functionally important role. In the case of further downsizing, the inner diameter in the vicinity of the insertion port 3 is reduced, but it may be bulged inward. Further, as shown in FIG. 1, on the outer peripheral surface of the joint body 2, the grout material injection hole 4 is opened at one point on the axial line in one flat portion 22 a, and the axial line is formed at substantially the center in the longitudinal direction. Two screw holes 5 are formed at positions slightly apart from each other. A bolt (not shown) is screwed into the screw hole 5, and the reinforcing bar is temporarily fixed by injecting the grout material and tightening the bolt until it is solidified. Further, exhaust ports 6 are respectively provided at the four corners of the one flat portion 22a.
[0017]
4 to 7 are cross-sectional views at each part for explaining the internal structure of the joint body 2. The inner space portion 8 of the joint body 2 is substantially divided into two by a flat wall-shaped portion 7 provided along the longitudinal direction thereof, so that the reinforcing bars are received in the respective divided inner space portions 8a and 8b. It has become. The inner diameters of these divided inner space portions 8a and 8b are formed somewhat larger so as to be loosely fitted when a reinforcing bar is inserted. The wall-like portion 7 is partly cut and divided immediately below the injection hole 4 of the grout material, but the wall-like portion 7 is continuous at a place other than the notch portion 7a, and both end faces of the joint body 2 Reached up to. Furthermore, a plurality of arc-shaped protrusions 9 are provided on the inner peripheral surface of the joint body 2 at appropriate intervals. As is apparent from FIG. 7, these arc-shaped protrusions 9 are provided over substantially the entire circumference of the inner surfaces of the divided inner space portions 8 a and 8 b, leaving a part of the wall-shaped portion 7. Here, the protruding height of each arcuate protrusion 9 is formed such that one flat portion 22a side is lower than the other flat portion 22b side. Moreover, the cross-sectional shape of the divided inner space portions 8a and 8b is formed in a substantially bowl shape in a place where the arc-shaped protrusion 9 does not exist, and is surrounded by the inner surface on the one flat portion 22a side and the base portion of the wall-shaped portion 7. The corner 81 forms an appropriate gap continuous in the longitudinal direction when the reinforcing bar is inserted, and serves as a grout material flow path. Of course, it is possible to form the arcuate protrusion 9 on the wall-like portion 7 as well.
[0018]
FIG. 8 is an explanatory view schematically showing a state in which the above-mentioned reinforcing bar joint 1 is applied to a column bar. Here, one band B is installed so as to surround the four columnar bars A arranged at the four corners of the rectangle, and the reinforcing bar joint 1 of the present invention is used for joining both end portions thereof. In this case, both end portions of the reinforcing bar B are vertically overlapped, and the flat portion 22a of the reinforcing bar joint 1 is mounted on the overlapping portion so as to be located on the outer side. That is, the band B is attached in a state where it is eccentric with respect to the reinforcing bar joint 1 so that the protruding height of the arc-shaped protrusion 9 is lower, so that the outer dimension of the column can be reduced. Here, the injection hole 4 and the like are provided in one flat portion 22a, and nothing is formed in the other flat portion 22b. Therefore, the external appearance shape of the joint body 2 is significantly different. It is hard to make a mistake when installing. It should be noted that providing a difference in the protruding height of the arcuate protrusion 9 is not an essential requirement, and the divided inner spaces 8a and 8b that receive the reinforcing bars do not have to be eccentric to one side.
[0019]
Next, a method for using the reinforcing bar joint 1 according to the present invention will be described with reference to FIGS. The process of inserting the end portion of the rebar B into the split inner space 8a, 8b of the rebar joint 1 is, of course, before the outer refit of the rebar B to the column main rebar A and after the outer fit. Also good. That is, it is combined with the column main reinforcement A in the state of the closed ring in which the reinforcing bar joint 1 is temporarily installed, or the band reinforcement B whose end is simply overlapped is directly fitted to the column main reinforcement A, and then the reinforcing bar joint 1 is attached. can do. In the latter case, one split inner space 8a in the reinforcing bar joint 1 is fitted to one end of the reinforcing bar B and inserted inward until it is removed from the overlapping portion. Next, the other end of the rebar B is inserted into the other divided inner space 8 b, and the reinforcing bar joint 1 is returned to a position where each end of the rebar B protrudes from the end face of the joint body 2 to the same extent.
[0020]
In the above insertion state, the reinforcing bar joint 1 and the band B are merely loosely fitted, and may move from a predetermined position until the grout material is injected or when the solidification is not sufficient. There is. For this reason, in this embodiment, a bolt for temporary fixing is screwed into the two screw holes 5, and the band B can be fixed by tightening the bolts. It should be noted that other temporary fixing means such as a clip may be used instead of the bolt, and such temporary fixing means may not be used in some cases.
[0021]
And an appropriate grout material is inject | poured into the inside through the injection hole 4 with respect to the reinforcing bar joint 1 in said temporary fixing state. As this injection method, it is possible to inject by natural falling by applying a funnel or using an appropriate injection gun. The grout material that has flowed into the inside from the injection hole 4 is divided into both divided inner space portions 8a and 8b at the notch portion 7a immediately below, and a flow path 81 formed on the one flat portion 22a side of the wall-shaped portion 7. And flows into the annular space between the arcuate projections 9 with certainty. At this time, air is pushed out by the presence of the exhaust port 6 so that the flow of the grout material is performed smoothly, and whether or not the grout material overflows from the exhaust port 6 is confirmed. Can be confirmed. If the gap between the opening 3 and the reinforcing bar is large, it may be closed with an appropriate sealing material, cap, etc., and if the injection hole 4 is located on the side as shown in the figure, The injection hole 4 may be sealed with an appropriate stopper after the injection of the grout material.
[0022]
Incidentally, with respect to the reinforcing bar joint 1 of the above example and the reinforcing bar joint formed in the same dimension as that of the example except that there is no wall-like portion as a comparative example, the pullout strength of the reinforcing bar was measured, respectively. The product was about 30% better than the comparative example. Therefore, when trying to obtain the same performance, the length of the joint body 2 can be shortened by that much, and the weight of the rebar joint 1 can be reduced. Moreover, since the grout material which consists of mortar which mixed the steel fiber can obtain about 50% performance improvement compared with the thing which does not contain a steel fiber, combined with the restraint effect by a wall-shaped part, the reinforcement joint 1 Greatly contributes to miniaturization and weight reduction.
[0023]
In the above embodiment, a plurality of independent substantially annular protrusions have been described as arc-shaped protrusions. However, this may be changed to a spiral one, or a wall-like part may be continuous to open an injection hole in each divided inner space. Of course, various modifications can be made within the technical idea of the present invention, such as making each of the divided inner spaces one at a time without opening them at both ends.
[0024]
【The invention's effect】
As described above, the reinforcing bar joint according to the present invention, the fitting body is provided with a wall-like portion for separating at least part of the overlapping portion in the longitudinal direction from each other rebar each other combined state overlapped with the inner hollow portion, the wall-like The inner space of the joint body is substantially divided into two by the portion, and the end of one reinforcing bar is inserted into each of the divided inner spaces from the opening on one end side to the other end, By inserting the ends of the other reinforcing bars from the opening on the other end side toward the one end, and arranging the ends of the reinforcing bars in an overlapped state with the wall-shaped portion interposed therebetween, each of the overlapping states The restraining effect of the grout material covering the periphery of the reinforcing bars is increased, and the rigidity of the joint body itself is greatly improved. For this reason, it is possible to shorten the length of the fixing portion of the reinforcing bar and further reduce the thickness of the joint body. As a result, the weight and size of the reinforcing bar joint can be reduced. This also leads to a reduction in the amount of grout material used, and in combination with the effects associated with weight reduction and the like, has a great effect on workability and cost improvement in rebar joining.
[0025]
Furthermore, when providing a wall-like part in a part of longitudinal direction, it is suitable if it provides in the both ends side of a coupling main body. In addition, it is possible to rationalize the grout material injection work by dividing the wall-shaped portion and opening a grout material injection hole in the divided portion, or by providing a flow path extending in the longitudinal direction along the wall-shaped portion. it can. Furthermore, it is possible to reduce the covering thickness of the concrete by decentering the protruding height of the arc-shaped protrusion, and the use of the grout material mixed with reinforcing fibers such as steel fibers has the above-mentioned effects It is effective in promoting
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a reinforcing bar joint according to the present invention.
FIG. 2 is a plan view of the reinforcing bar joint shown in FIG.
3 is a left side view of the reinforcing bar joint shown in FIG. 1. FIG.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is a cross-sectional view taken along line BB in FIG.
6 is a cross-sectional view taken along line CC in FIG. 1. FIG.
7 is a sectional view taken along line DD in FIG. 1. FIG.
FIG. 8 is an explanatory view showing a usage state of the reinforcing bar joint shown in FIG. 1;
[Explanation of symbols]
A ... main reinforcement, B ... shear reinforcement (strand), 1 ... reinforcing bar joint, 2 ... joint body, 3 ... insertion port, 4 ... injection hole, 5 ... screw hole, 6 ... exhaust port, 7 ... wall-shaped part, 7a ... notch, 8 ... inner cavity, 9 ... arc-shaped protrusion

Claims (6)

Inserting the ends of the reinforcing bars in opposite directions from the openings on both ends into the cylindrical joint body with the arc-shaped projections formed on the inner surface of the peripheral wall, the reinforcing bars are superposed in the inner space, In the reinforcing bar joint which joins these reinforcing bars through the grout material filled in the inner space from the injection hole opened in the peripheral wall, the joint main body has the reinforcing bars superposed on each other in the longitudinal direction. A wall-like portion separated by at least a part of the overlapping portion is provided, and the inner hollow portion of the joint main body is substantially divided into two by the wall-like portion, and one reinforcing bar is provided in each of the divided inner hollow portions. Insert the end of the rebar from the opening on one end to the other end, insert the end of the other rebar from the opening on the other end to the one end, and the ends of these rebars are walls arranged to be joined to the mating state overlapped across the Jo portion Rebar joint characterized. The rebar joint according to claim 1, wherein the wall-like portion is provided at at least both end portions of the joint body. 3. The reinforcing bar joint according to claim 1, wherein the wall-shaped portion is divided at a part in a longitudinal direction, and an injection hole is communicated with the divided portion. The reinforcing bar joint according to any one of claims 1 to 3, wherein a flow path of a grout material continuous in the longitudinal direction is provided on the injection hole side of the wall-like portion. The reinforcing bar joint according to any one of claims 1 to 4, wherein the injection hole side of the arcuate protrusion is formed lower than the opposite side in the radial direction. The joint body used in two rebar joint according to any one of claims 1 to 5, repeated rebar together at the inner hollow portion by inserting the end portion of each reinforcing bar from the opening at both ends in opposite directions A reinforcing bar joining method, characterized by filling the inner space with a grout material containing reinforcing fibers from an injection hole formed in the peripheral wall and joining the reinforcing bars together .

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