JP3993847B2 - Reinforcing bar anchoring structure - Google Patents

Description

  The present invention relates to a reinforcing bar fixing structure for fixing a deformed reinforcing bar arranged in a column or a beam to concrete and strengthening a pulling force of the reinforcing bar.

  Conventionally, in order to reinforce concrete with extremely low tensile strength, reinforced concrete structures in which reinforcing bars are reinforced to enhance the overall tensile strength have been widely used. However, if the holding power of the concrete with respect to the reinforcing bars is weak, when a tensile force is applied due to bending or the like, the reinforcing bars are pulled out and a sufficient tensile strength cannot be exhibited. Therefore, many fixing means for reinforcing bars have been proposed in order to ensure the holding power of concrete against the reinforcing bars.

  For example, a parallel or screw-like protruding node provided on the outer periphery of the reinforcing bar to improve the pulling force against the concrete (hereinafter referred to as “deformed reinforcing bar”) is widely used. In addition, when the deformed reinforcing bar is not sufficient, means for improving the pulling force on the concrete by bending the end or intermediate part of the reinforcing bar is widely used. Furthermore, with the means to bend the reinforcing bars, when reinforcing bars are densely arranged, the reinforcing bars to be bent may interfere with each other or there may be insufficient space for bending work. Means for attaching the fuser member are provided.

That is, a means has been proposed in which a plate-like fixing member is screwed into the end portion of the screw rebar, and a filler such as mortar is injected into the screwed portion (see, for example, Patent Document 1). Or the means to form an enlarged diameter part in the edge part of a reinforcing bar by hot upsetting is proposed (for example, refer to patent documents 2). Furthermore, a means has also been proposed in which a male screw is friction-welded to the end of the reinforcing bar and a fixing plate is screwed onto the male screw (see, for example, Patent Document 3).
Japanese Patent No. 2662150 (page 1-4, FIGS. 7-8) JP 2000-257209 A (page 1-4, FIG. 1) JP 2001-159214 A (page 1-4, FIG. 1)

  However, in a means for screwing a plate-shaped fixing member to the end of the screw rebar and injecting a filler such as mortar into this screwed portion, the applicable rebar is limited to only the screw rebar, and the fixing portion is The manufacturing cost is increased because it is necessary to screw a female screw matched to the screw rebar. Further, it is necessary to inject the filler. Moreover, in the means for forming the enlarged diameter portion at the end of the reinforcing bar by hot upsetting, the end of the reinforcing bar is heated red by a burner or a high-frequency coil, and a predetermined mold is pressed against the end of the reinforcing bar. Means are needed. Therefore, in order to form a uniform enlarged diameter part, a certain level of skill is required, and the work load under high temperatures such as under hot weather in summer is excessive, and burns may occur at sites with poor workability. There is also the danger of.

  In the means for friction-welding a male screw to the end of the reinforcing bar and screwing the fixing plate into the male screw, two types of parts are prepared: a male screw and a fixing plate provided with a female screw to be screwed into the male screw. Is required. For example, when connecting a beam to a column, it is often necessary to lengthen the protruding length of the reinforcing bar from the end face of the beam to some extent, but in such a case, in order to frictionally weld the male screw properly This requires a means for fixing the protruding reinforcing bar so that it does not bend or swing, or a highly skilled technique.

  Accordingly, an object of the present invention is to provide a reinforcing bar fixing structure in which deformed reinforcing bars are fixed to concrete by low-cost and simple means that does not require skilled techniques, and the reinforcing force of the reinforcing bars is increased.

  In order to solve the above problems, a first feature of the reinforcing bar fixing structure according to the present invention includes a reinforcing bar and a fixing member, and the reinforcing bar is a deformed reinforcing bar having a bamboo knot or a screw-like knot. This is a cylindrical member having a hollow hole into which the reinforcing bar can be inserted, and is reduced in diameter by pressing the outer periphery of the cylindrical member and is crimped to the outer periphery of the reinforcing bar.

  Further, the second feature of the reinforcing bar fixing structure according to the present invention is that the fixing member described in the above feature 1 is reduced in diameter by a predetermined length portion of its axial length and is crimped to the outer periphery of the reinforcing bar. There is to be. Furthermore, the third feature of the fixing structure of the reinforcing bar according to the present invention is that the fixing member described in the above feature 2 has a predetermined length reduced from one end thereof and is crimped to the outer periphery of the reinforcing bar. The diameter of the part is expanded.

  According to a fourth feature of the reinforcing bar fixing structure according to the present invention, the other length portion of the fixing member described in the above feature 3 is formed by folding the entire circumference inward in the enlarged diameter portion and the maximum enlarged diameter portion. And formed end portions. Here, it is desirable that the thickness of the other length portion of the fixing member described in any one of the features 3 to 4 is thinner than the predetermined length portion.

  A fifth feature of the reinforcing bar fixing structure according to the present invention is that the predetermined length portion of the fixing member described in any one of the above features 1 to 5 is reduced in diameter in two steps. . That is, after the predetermined length portion is compressed and deformed by pressing the outer peripheral surface with a plurality of first pressing claws arranged symmetrically about the axis, the outer peripheral surface shifted by a half pitch from the first pressing claw is By pressing with a plurality of second pressing claws that are arranged symmetrically about the axis and have an arc pressing surface with a predetermined circumferential length, the inner side surface corresponding mainly to the portion pressed by the first pressing claws is It is crimped to the outer periphery of the reinforcing bar.

  The above reinforcing bar fixing structure is not limited to the case where the diameter is reduced or expanded at the construction site by using a portable pressing device such as a die, but cold working such as cold forging or pressing is used in the factory. In addition, it is also possible to use a product obtained by previously crimping and expanding the diameter of the fixing member on the deformed reinforcing bar and carrying it to the construction site.

  By configuring the invention in this way, the following effects can be obtained. First, the fixing member can be manufactured at a low cost because a hollow cylindrical member into which a deformed reinforcing bar can be inserted is cut to a certain length. In particular, when a hollow pipe is used as a hollow cylindrical member, it can be manufactured or obtained at a very low cost.

  Second, the outer circumference of a predetermined length portion of the hollow cylindrical member is pressed and compressed with a die having, for example, an arc groove shape, and the inner circumference of the hollow hole is bitten into a deformed reinforcing bar to be crimped. Therefore, it is not necessary to process a female screw that is screwed into a screw hole or the like in the hollow hole of the fixing member. In addition, since the hollow cylindrical member is plastically deformed and crimped, the inner peripheral dimension of the hollow hole only needs to allow for clearance into which the deformed reinforcing bar can be inserted, and does not require high processing accuracy. Furthermore, since crimping to the deformed reinforcing bar is merely by pressing and compressing the outer periphery of the hollow cylindrical member with a die or the like, the crimping operation can be performed extremely easily and reliably as compared with hot installation processing or friction welding. Therefore, no skill is required, and the work burden and danger can be greatly reduced.

  Thirdly, by reducing the diameter of only a predetermined length of the axial length of the fixing member, the radial direction on the outer circumference between the other lengths of the original outer shape that is not pressed is reduced. Therefore, the fixing force to concrete can be increased by this step.

  Fourth, the die is pressed against one end of the fixing member to expand the other length portion, for example, in a divergent shape, so that a large-diameter expansion tool is not required, and particularly skilled techniques are used. It is not necessary to form a sufficient fixing area for the concrete. Fifth, by expanding the other length portion of the fixing member and folding the entire circumference inward at the maximum expanded portion to form a terminal portion, the expanded portion becomes a double wall, so that the reinforcing bar The strength with respect to the pulling force can be increased. Furthermore, such a shape can be formed quickly and easily in one step of pressing a die or the like against one end surface of the fixing member.

  Sixth, by reducing the thickness of the portion where the fixing member is expanded, the pressing force of a die or the like can be reduced, and the diameter can be increased more easily. Seventh, a predetermined length portion of the fixing member is pressed partially in two steps by a plurality of first pressing claws and second pressing claws arranged symmetrically about the axis. By doing so, even if the fixing member has a large radial clearance between the hollow hole and the outer periphery of the reinforcing bar, the fixing member can be compressed and deformed with a small pressing force, and can be securely pressed onto the outer periphery of the reinforcing bar. Accordingly, the step in the outer peripheral radial direction can be increased with other length portions that are not pressed, so that the fixing force to the concrete can be increased.

  First, an example of using the reinforcing bar fixing structure according to the present invention will be described with reference to FIG. FIG. 1 exemplifies a case where a reinforcing bar fixing structure 1 is used for a structure in which concrete beams 4 and columns 5 are combined. That is, the reinforcing bar fixing structure 1 includes a reinforcing bar 2 and a fixing member 3 that is crimped to the end of the reinforcing bar. A plurality of reinforcing bars 2 are embedded along the longitudinal direction of the beam 4, and each tip portion protrudes from the end face of the beam and is disposed between the reinforcing bars 6 embedded in the column 5. Therefore, the fixing member 3 becomes a great resistance against the pulling force of the reinforcing bar 2 and can securely hold the reinforcing bar to the column 5 and the beam 4. The bending stress generated on the lower surface of the beam and Sufficient strength can be ensured against the separation force and the like.

  2A to 2B show details of the reinforcing bar fixing structure 1. FIG. In other words, the reinforcing bar 2 is a deformed reinforcing bar in which bamboo bars 22 that are parallel to the round bar 21 at a predetermined pitch are integrally formed. The bamboo knots 22 are roll-formed half a turn across a rib 23 provided along the longitudinal direction. Instead of the parallel bamboo joint 22, a deformed reinforcing bar having a screw-like joint may be used. On the other hand, as shown in FIGS. 2C to 2D, the fixing member 3 uses a short steel tubular member having a square cross-sectional shape having a circular hollow hole 31 into which the reinforcing bar 2 can be inserted. .

  2E, one end of the reinforcing bar 2 is inserted into the hollow hole 31, and the parallel sides 32 on the outer periphery of the fixing member 3 are sandwiched by a pair of dies 8 having arc grooves 8a facing each other. Press. When the outer periphery of the fixing member 3 is pressed in this way, the four corners of the quadrangle are pressed in the center direction by the arc grooves 8a, respectively, and are compressed and deformed from this portion, and the inner periphery of the hollow hole 31 in this portion is Crimp to the outer periphery. Finally, as shown in FIG. 2 (B), the outer periphery 32b of the fixing member 3 is compressed and deformed so as to have an elliptical shape close to a circle, and the entire inner circumference of the hollow hole 31 is substantially the same as that of the reinforcing bar 2. Crimp so that it digs into bamboo shoot 22.

  By the way, when the outer periphery of the fixing member 3 is polygonal like a square cross section in this way, each corner is first compressed and deformed by the arc groove 8a of the die 8, and then compressed and deformed into an elliptical shape close to a circle. Therefore, since the compression deformation is performed in two stages, the outer periphery of the fixing member 3 is formed in a circular shape and pressed over the entire periphery, so that the pressing force can be reduced as compared with the case where the compression deformation is performed at once. . For this reason, the die pressing means can be reduced in size. In addition, since the thick fixing member 3 can be easily reduced in diameter, the fixing area for the concrete can be increased. Further, the clearance between the hollow hole 31 and the outer diameter of the bamboo joint 22 of the reinforcing bar 2 is sufficient if it is large enough to ensure a sufficient pressure-bonding force due to plastic deformation, and need not be processed precisely.

  3A to 3B show another embodiment. 2 are numbered by adding 100 to the numbers shown in FIG. 2 for convenience of reference. That is, as the fixing member 103, as shown in FIGS. 3C to 3D, a cylindrical member having a hexagonal cross section having a hollow hole 131 into which the reinforcing bar 102 can be inserted is used. Then, as shown in FIG. 3 (E), the end of the reinforcing bar 102 is inserted into the hollow hole 131, and the length of the inserted portion is the same as that of FIG. 2 (E), and the die 108 having the arc groove 108a. Press and reduce the diameter and press the outer periphery of the reinforcing bar.

  Therefore, as shown in FIGS. 3A to 3B, the outer periphery of the fixing member 103 is not reduced in diameter as the original hexagonal shape and the portion 132 a that is pressed and reduced in diameter into a substantially circular cross-sectional shape. A step in the outer peripheral radial direction is generated between the portion 132b and the fixing force on the concrete can be enhanced by the step.

  A reinforcing bar fixing structure 201 shown in FIGS. 4A to 4B is obtained by reducing the diameter of a predetermined length portion of the fixing member and expanding the other length portions. 2 are numbered by adding 200 to the numbers shown in FIG. 2 for convenience of reference. In other words, as shown in FIGS. 4C to 4D, the fixing member 203 uses a hollow pipe having a hollow hole 231 into which the reinforcing bar 202 can be inserted. Then, only a half portion from one end is formed in the thin portion 231b.

  As shown in FIG. 4E, the fixing member 203 first expands the diameter of the thin portion 231b. That is, the hollow 231 and the outer peripheral portion 232 corresponding to this length are attached and fixed to the chucks 292 and 293, and the die 291 having the cylindrical protrusion 291a that can be inserted into the inner periphery of the thin portion 231b is formed into this thin-walled portion. Press against the end of the part. When pressed, the end of the thin portion 231b is first expanded by the rounded portion 291b at the base of the cylindrical protrusion 291a, and then the expanded end is further expanded by the flat portion 291c of the die 291. As shown in FIG. 4 (F), a portion 232b having a diameter expanded in a divergent shape is formed.

  Next, as shown in FIG. 4 (G), a reinforcing bar 202 is inserted into a hollow hole 231 that has not been expanded, and the insertion length of the die having an arc groove 208a is the same as in FIG. 2 (E). It is pressed and reduced in diameter by 208 and is crimped to the outer periphery of this reinforcing bar. As described above, in the fixing member 203, as shown in FIGS. 4A to 4B, the thin-walled portion 231b is expanded in a divergent shape, and the remaining portion 232a is reduced in diameter and is crimped to the outer periphery of the reinforcing bar 202. It becomes composition. Therefore, a large fixing force with respect to the concrete can be obtained by the portion 232b expanded in a divergent shape.

  The reinforcing bar fixing structure 301 shown in FIGS. 5 (A) to 5 (B) has a double structure by expanding the diameter of about half the length of the fixing member and folding the entire periphery of the end portion inward. Is. 2 are numbered by adding 300 to the numbers shown in FIG. 2 for convenience of reference. That is, as shown in FIGS. 5C to 5D, the fixing member 303 uses a thin hollow pipe having a hollow hole 331 into which the reinforcing bar 302 can be inserted.

  As shown in FIG. 5E, first, inner and outer peripheries 331 and 332 of about half the length of the fixing member 303 are inserted and attached to chucks 392 and 393, respectively. Next, a die 391 having a flat surface 391 a is pressed against the end surface of the fixing member 303. When pressed to some extent, the predetermined length portion of the fixing member 303 buckles between the pressing end surface and the mounting end surfaces of the chucks 392 and 393 so as to bulge outward. When the pressure is further advanced, the portion bulging outward is compressed in the axial direction. Finally, as shown in FIG. 5 (F), the expanded diameter portion 332b and the maximum expanded diameter portion 332c A terminal portion 332d formed by folding the entire circumference inward is formed.

  As shown in FIG. 5 (G), the remaining approximately half length portion 332a that is not expanded is reduced in diameter by the same means as in FIG. 4 (G) described above and is crimped to the outer periphery of the reinforcing bar 302.

  The reinforcing bar fixing structure 401 shown in FIGS. 6A to 6B is obtained by reducing the diameter of a predetermined length portion of the fixing member in two steps. 2 are numbered by adding 400 to the numbers shown in FIG. 2 for convenience of reference. That is, the fixing member 403 uses a thin hollow pipe having a hollow hole 431 sufficiently larger than the outer diameter of the reinforcing bar 402 as shown in FIGS.

  As shown in FIG. 6 (E), about four portions of the fixing member 403 are first pressed by four trapezoidal dies 481 arranged axially symmetrically to press and compress the four locations on the outer periphery 432. Let The cross-sectional shape after the compression deformation is such that the portion where the pressing surface 481a of the die 481 contacts is reduced in diameter to a substantially flat portion 432a, and the four corner portions that are not pressed are deformed into a substantially arc-shaped portion 432c. The pressing position of the die 481 is adjusted so that the center interval of the flat portion 432a is slightly wider than the outer periphery of the reinforcing bar 402.

  Next, as shown in FIG. 6 (F), a rebar 402 is inserted into the hollow hole 431a whose diameter has been reduced, and an approximately arc-shaped portion is formed by the above-described dice 481 and four dice 482 shifted by a half pitch in the circumferential direction. Press 432c. When the arc-shaped portion 432c is pressed toward the center direction in this way, the adjacent flat portion 432a is further reduced in diameter and is crimped to the outer periphery of the reinforcing bar 402. Since the arc pressing surface 482a of the die 482 is formed in a concave arc shape along the surface of the arc-shaped portion 432c, the contact surface slips when pressed, and the diameter of the adjacent flat portion 432a is reduced. It can prevent non-uniformity.

  As described above, the fixing member 403 is compressed and deformed by dividing the outer periphery partly in two steps, so that the fixing member 403 can be greatly reduced in diameter with a relatively small pressing force, and the outer peripheral radial step with respect to the part that is not reduced in diameter. It is possible to increase the fixing power to concrete. The number of dies 481 and 482 is not limited to four, but may be three, or five or more as long as it is axially symmetric. Further, the pressing surface 481a of the first pressing claw 481 is not limited to a flat surface as illustrated, and may be a convex arc surface.

  In any of the above-mentioned reinforcing bar fixing structures, a fixing member may be crimped to one end of a reinforcing bar embedded in concrete, and then a predetermined length portion may be expanded using a portable die or the like. it can. However, as described above, it is preferable in terms of workability, safety, etc., to first expand the diameter of a predetermined length, bring it into the fixing site, and press-bond it to one end of the reinforcing bar.

  The reinforcing structure for reinforcing bars according to the present invention can be widely applied to reinforced concrete structures because the pulling force of the reinforcing bars can be strengthened by low-cost and simple means that does not require skilled skills.

It is a whole block diagram at the time of using the fixation structure of a reinforcing bar for the coupling | bonding of a beam and a column. It is explanatory drawing which shows the fixing structure of a reinforcing bar, and its manufacturing means. It is explanatory drawing which shows the fixing structure of another reinforcing bar, and its manufacturing means. It is explanatory drawing which shows the fixing structure of another reinforcing bar, and its manufacturing means. It is explanatory drawing which shows the fixing structure of another reinforcing bar, and its manufacturing means. It is explanatory drawing which shows the fixing structure of another reinforcing bar, and its manufacturing means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101-401 Reinforcing bar fixing structure 2,102-402 Reinforcing bar 22,122-422 Bamboo knot 231b Thin portion 232b Expanded portion 291 Die 292,293 Chuck 3,103-403 Fixing member 31, 131-431 Hollow hole 32, 132 to 432 Outer periphery 332c Maximum diameter expanded portion 332d Termination portion 391 Die 392, 393 Chuck 4 Concrete 481 Die (first pressing claw)
482 Dice (second pressing claw)
482a Arc pressing surface 5 Concrete 6 Vertical reinforcement 8, 108 to 308 Dies 8a, 108a to 308a Arc groove

Claims (5)

With reinforcing bars and fixing members,
The rebar is a deformed rebar having a bamboo knot or a screw-shaped knot,
The fixing member is a cylindrical member having a hollow hole into which the reinforcing bar can be inserted. The outer periphery of a predetermined axial length portion of the cylindrical member is pressed and compressed to be pressed against the outer periphery of the reinforcing bar. Reinforcing bar anchoring structure characterized by being. The fixing member according to claim 1, wherein the fixing member has a predetermined length reduced from one end thereof, and is crimped to the outer periphery of the reinforcing bar, and the other length portion is expanded. Construction. 3. The fixing member according to claim 2, wherein the other length portion of the fixing member includes a diameter-expanded portion and a terminal portion formed by folding the entire circumference inward at the maximum diameter-expanded portion. Reinforcing bar fixing structure. In any of the claims 2-3, the thickness of the other lengths of said fixing member includes a fixing structure rebar, characterized that it is thinner than said predetermined length portion. In one claim 1, the fixing member, after allowed to compressive deformation by pressing its outer peripheral surface by the plurality of first pressing pawl disposed in axial symmetry, and the first pressing pawl The outer peripheral surface shifted by a half pitch is pressed by the first pressing claws mainly by pressing the outer circumferential surfaces with a plurality of second pressing claws having an arc pressing surface arranged in an axial symmetry and having a predetermined circumferential length. A reinforcing bar fixing structure, wherein an inner side surface corresponding to a portion is crimped to the outer periphery of the reinforcing bar.

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