JP2019035306A - Reinforced concrete structure - Google Patents

Abstract

To employ a mechanical anchorage method to an axial reinforcement by laying a strengthening reinforcement extending in parallel with the axial reinforcement having a mechanical anchorage member at a reinforcement concrete column/beam joining part, to move a damaged point resulting from a yield of the reinforcement to a span center side of a column, and to improve deformation performance.SOLUTION: A reinforcing concrete structure comprises concrete 21, an axial reinforcement embedded into the concrete 21, and a strengthening reinforcement 12 embedded into the concrete 21 while being at least partially overlapped on the axial reinforcement. The axial reinforcement includes a mechanical anchorage member attached to its tip, and the strengthening reinforcement 12 extends in parallel with the axial reinforcement at the inside of the axial reinforcement over an indispensable overlap range which is not shorter than a length necessary for transmitting a tensile force which is received by the axial reinforcement.SELECTED DRAWING: Figure 6

Description

  The present disclosure relates to a reinforced concrete structure.

  Conventionally, reinforced concrete structures (RC structures) made of reinforced concrete (RC) have been widely used as civil structures such as railway viaducts. The RC beam-column joint, which is the joint between the column and the beam in such an RC structure, is generally determined in consideration of deformation at the time of the occurrence of an earthquake, so if the deformation performance can be improved Can be a reasonable structure. And in the seismic design of railway viaduct columns, piers, etc., the deformation performance of RC beam-column joints should be improved in consideration of the fact that the columns are generally designed to yield and break in advance. Is important.

  In RC beam-column joints, fixing (fixing) of axial reinforcing bars in the joints is important. Therefore, in civil engineering structures, a method using a standard hook such as a semicircular hook is adopted as a fixing method for the axial rebar. In addition, a semicircular hook, a right angle hook, or an acute angle hook is defined as a standard hook in the Japan Society of Civil Engineers Concrete Standard Specification Design Edition (2012). However, with the thinning of the members and the increase in the diameter of the reinforcing bars for improving the seismic performance, in the RC column beam joint, the bar arrangement in the joint is becoming dense.

  FIG. 1 is a photograph showing an example of bar arrangement in a joint in a conventional RC column beam joint. In addition, in a figure, (a) is a photograph which shows the example of the overcrowded reinforcement in a junction part, (b) is a photograph which shows the example of the construction defect resulting from overcrowded reinforcement.

  As shown in FIG. 1A, when the bars are arranged according to the conventional specification, the standard hooks of the column axis reinforcing bars and the bending fixing of the beam axis reinforcing bars are congested three-dimensionally in the joint. Therefore, the workability of rebar assembly deteriorates, and the perforation of the rebar (distance between the surfaces of the rebar) is not sufficiently secured, so that the workability of concrete placement is lowered, as shown in FIG. 1 (b). In addition, poor construction may occur.

  Therefore, it has been proposed to employ a mechanical fixing method in which a mechanical fixing member is attached to a reinforcing bar instead of a method using a standard hook (for example, see Patent Document 1).

JP 2010-037777 A

However, there are various types of mechanical anchoring methods that have been classified into axial rebars and transverse rebars, which have been evaluated by public examination agencies. The products that have been approved for use have many architectural grades and few civil engineering grades (see, for example, Non-Patent Document 1). Therefore, in civil engineering structures, the adoption of a mechanical fixing method for axial rebars has not progressed. Also, in the performance evaluation tests (static proof stress, high stress repetition performance, etc.) of various mechanical anchoring methods, the axial rebar is embedded in massive concrete, that is, with sufficient cover (from the rebar surface to the concrete surface). The shortest distance) is ensured, and the behavior of the axial rebar in a state where the cover is around 100 [mm] as in an actual RC beam-column joint has not been sufficiently elucidated.
Japan Society of Civil Engineers, “Concrete Library No. 128, Reinforcing Bars and Joint Guidelines [2007]”, 2007.8

In addition, as an element test or an element experiment assuming actual use conditions, a static tensile test for confirming uniaxial tensile characteristics using a cover and a transverse rebar ratio as a parameter, and an axial direction of an L-shaped joint in an RC column beam joint A positive / negative alternating loading experiment in which a reinforcing bar having a mechanical fixing member is applied to the reinforcing bar is performed (for example, see Non-Patent Documents 2 and 3).
Toshiya Tadokoro, Yukihiro Tanimura, Mitsuhiro Tokunaga, Daiki Yoneda, “Static Tensile Properties of Anchorage Using Mechanical Anchorage at Viaduct Joint”, Annual Report of Concrete Engineering, Vol. 31, no. 2, 2009 Yoshiyuki, Y., et al., “Experimental study on anchorage performance of column axial rebar at RC beam joint of RC ramen viaduct”, Civil Engineering Society 64th Annual Lecture, V-500, 2009.9

  FIG. 2 is a diagram for explaining a tensile test of a conventional axial reinforcing bar embedded in concrete, and FIG. 3 is a diagram for explaining a conventional positive / negative alternating loading test. 2, (a) is a conceptual diagram of a uniaxial tensile property test, (b) is a photograph showing a fracture state of concrete, and in FIG. 3, (a) is a conceptual diagram of a positive / negative alternating loading test, (b ) Is a photograph showing the destruction of concrete.

  In the case of the static tensile test to confirm the uniaxial tensile characteristics as shown in FIG. 2, the reinforcing bar having the fixing plate as the mechanical fixing member satisfies the designed tensile strength, but before the reinforcing bar is tensile-yield, There was a specimen that showed a brittle fracture state because cracking occurred in the concrete at the cover portion at the position of the fixing plate in FIG.

  Further, in the case of the positive / negative alternating loading test as shown in FIG. 3, after the steel bar is pulled and yielded, the cover part is peeled off to the concrete at the position of the fixing plate which is a mechanical fixing member, as in the example shown in FIG. As a result, the fixing force was lost, and the load decreased before the design strength was reached.

  From the results of the static tensile test and the positive / negative alternating loading test, if the mechanical fixing method is adopted for the reinforcing bar in the part where the fog is small like the RC beam-column joint, the required performance may not be satisfied. I understand that.

  The tensile strength of the reinforcing bar having the mechanical fixing member is contributed by the fixing length, which is the length of the reinforcing bar from the attachment position of the mechanical fixing member, and the support pressure transmitted from the mechanical fixing member to the concrete. However, when the reinforcing bar yields tensile strength, the plastic zone develops and the adhesive force along the surface of the reinforcing bar decreases, and the tensile strength of the reinforcing bar in the final state is almost equal to the bearing pressure transmitted from the mechanical fixing member to the concrete. Determined by.

  FIG. 4 is a diagram for explaining a difference in bearing pressure transmitted to concrete from a conventional reinforcing steel standard hook and a mechanical fixing member, and FIG. 5 is a photograph showing a fixing state of a conventional reinforcing steel standard hook and a mechanical fixing member. is there. 4 and 5, (a) is a diagram and a photograph when the reinforcing bar has a standard hook, and (b) is a diagram and a photograph when the reinforcing bar has a mechanical fixing member.

  In the figure, 21 is concrete, and 11 is a main reinforcing bar as an axial reinforcing bar embedded in the concrete 21. 4A is formed with a semicircular hook 13 as a standard hook at its upper end, and the main rebar 11 in FIG. 4B is a fixing plate as a mechanical fixing member at its upper end. 14 is attached. The fixing plate 14 is, for example, a circular plate having an outer diameter larger than that of the main reinforcing bar 11 and is a plate member attached to the end of the main reinforcing bar 11 by screwing, but may be any kind of member.

As shown in FIG. 4A, when a tensile force P <b> 1 as indicated by an arrow is applied to the main reinforcing bar 11, the support pressure P <b> 2 that is a force from the semicircular hook 13 is directed toward the inside of the concrete 21. Is transmitted. On the other hand, as shown in FIG. 4B, the fixing plate 14 has a smaller volume and occupying range of the portion functioning as the fixing portion than the semicircular hook 13. The supporting pressure P2 is transmitted toward the surface 21a. Therefore, when the fog on the fixing plate 14, that is, when the shortest distance from the surface of the fixing plate 14 to the surface 21 a of the concrete 21 is small, a crack occurs in the cover portion, and as shown in FIG. The concrete 21 is peeled off or peeled off at the cover portion such as destruction. In this case, the fixing plate 14 is completely exposed and the tensile resistance is lost. On the other hand, in the case of the semicircular hook 13, as shown in FIG. 5A, even if the concrete 21 is peeled off or peeled off at the cover portion, the portion that functions as the fixing portion of the semicircular hook 13 is the concrete 21. Since it is located inside, a certain amount of tensile force can be expected. As described above, when the mechanical fixing method is employed, there is a possibility that the deformation performance is lowered (for example, see Non-Patent Document 4).
Furuya Takumi, Watanabe Ken, Tadokoro Toshiya, Hattori Naomichi, “Effects of reinforcement and anchorage of beam-to-column connections of ramen viaducts on column member performance”, Concrete Engineering Annual Papers, Vol. 39, no. 2, 2017

  Here, by solving the problems of the above-mentioned conventional technology and arranging reinforcing reinforcing bars extending side by side with the axial reinforcing bars having mechanical fixing members in the reinforced concrete beam-column joints, the machine is applied to the axial reinforcing bars. It is an object of the present invention to provide a reinforced concrete structure that can adopt a type fixing method and can move a damaged portion due to the yielding of the reinforcing bar toward the center of the span of the column, thereby improving the deformation performance.

  Therefore, a reinforced concrete structure includes concrete, an axial rebar embedded in the concrete, and a reinforcing rebar embedded in the concrete at least partially overlapping with the axial rebar, and the shaft The directional reinforcing bar includes a mechanical fixing member attached to the tip, and the reinforcing reinforcing bar extends over the essential overlap range longer than the length necessary for transmitting the tensile force received by the axial reinforcing bar. Inside the directional reinforcement, it extends alongside the axial reinforcement.

  In another reinforced concrete structure, the axial rebar extends linearly in the column extending direction, the mechanical fixing member is located in a joint between the column and the beam, and the essential overlap range is provided. Is a range in which the reinforcing reinforcing bars are linearly extended in parallel in the vicinity of the axial reinforcing bars on the column side of the joint end face.

  In still another reinforced concrete structure, when the axial rebar is subjected to a tensile force, the strain generated in the axial rebar is the end of the essential overlap range and the end opposite to the joint end face. It becomes the maximum in the vicinity of.

  In still another reinforced concrete structure, the reinforcing reinforcing bar is required to be fixed beyond the length necessary for transmitting the tensile force received from the axial reinforcing bar to the surrounding concrete outside the essential overlap range. Extends over a range.

  In still another reinforced concrete structure, the necessary fixing range is a range in which the reinforcing reinforcing bars are linearly extended in parallel with each other in the vicinity of the axial reinforcing bars on the joint side of the joint end face. .

  In still another reinforced concrete structure, the necessary fixing range is a range in which the reinforcing reinforcing bar is curved and extends on the joint side of the joint end face.

  In still another reinforced concrete structure, in the necessary fixing range, the reinforcing reinforcing bar is curved so that the bending inner radius is not less than 10 times the diameter.

  According to the present disclosure, the reinforcing reinforcing bars extending alongside the axial reinforcing bars having the mechanical fixing members at the reinforced concrete column beam joints are disposed. As a result, it is possible to employ a mechanical fixing method for the axial rebar, and to move the damaged portion due to the yield of the rebar closer to the center of the span of the column, thereby improving the deformation performance. .

It is a photograph which shows the example of the bar arrangement in the junction part in the conventional RC column beam junction part. It is a figure explaining the tensile test of the axial direction reinforcement embedded in the conventional concrete. It is a figure explaining the conventional positive / negative alternating loading experiment. It is a figure explaining the difference in the bearing pressure transmitted to concrete from the conventional hook of a conventional reinforcing bar and a mechanical fixing member. It is a photograph which shows the fixing condition of the conventional hook of a conventional reinforcing bar and a mechanical fixing member. It is a schematic cross section of the reinforced concrete structure in 1st Embodiment. It is a schematic cross section of the comparative example of the reinforced concrete structure in 1st Embodiment. It is a schematic cross section of the reinforced concrete structure in 2nd Embodiment.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings.

  FIG. 6 is a schematic sectional view of a reinforced concrete structure according to the first embodiment, and FIG. 7 is a schematic sectional view of a comparative example of the reinforced concrete structure according to the first embodiment.

  In FIG. 6, reference numeral 20 denotes a reinforced concrete structure according to the present embodiment, which is a joint 24 between a reinforced concrete column 22 and a beam 23 and its peripheral portion. The reinforced concrete structure 20 is typically a civil engineering structure such as a viaduct, and may be for railroads, roads, or any use. However, here, for the sake of explanation, the description will be made assuming that the RC column beam joint and its peripheral part in a railway viaduct are used.

  In the present embodiment, the description in the section “Problems to be solved by the invention” is incorporated, and the structure, operation, and effect of each part in the reinforced concrete structure 20 are described. About the same thing as what was demonstrated in the term of ", the code | symbol same as the code | symbol shown by FIG. 4 is provided, and description is abbreviate | omitted suitably.

  Further, in the present embodiment, the expressions indicating directions such as upper, lower, left, right, front, rear, etc. used for explaining the configuration and operation of each part of the reinforced concrete structure 20 and other members are absolute. It is a relative rather than a typical one, and is appropriate when each part of the reinforced concrete structure 20 and other members are in the posture shown in the figure, but when the posture changes, the posture changes. It should be interpreted accordingly.

  In the example shown in FIG. 6, the main reinforcing bar 11 as the axial reinforcing bar embedded in the concrete 21 is a reinforcing bar extending in the extending direction (vertical direction) of the column 22. In addition, although many axial rebars are embedded in the concrete 21, in FIG. 6, for the convenience of illustration, the two main reinforcing bars closest to the left and right surfaces 21a of the concrete 21 in the column 22 are shown. Only 11 is shown. Further, it is assumed that the axial direction of the main reinforcing bar 11 is parallel to the surface 21 a of the concrete 21. Furthermore, the front-end | tip (upper end) of the main reinforcing bar 11 is located in the junction part 24, and the fixing plate 14 as a mechanical fixing member is attached there.

  A reinforcing reinforcing bar 12 is disposed inside the main reinforcing bar 11 (on the side opposite to the surface 21a). In addition, the arrangement | positioning position of this reinforcement reinforcing bar 12 is not necessarily limited to the inner side of the main reinforcing bar 11, and if the perforation of the reinforcing bar is ensured, between the main reinforcing bars 11 (the main reinforcing bar 11 and The distance from the surface 12a of the reinforcing steel bar 12 may be the same). The reinforcing reinforcing bars 12 are straight bars extending linearly in parallel with the main reinforcing bars 11, but their length is shorter than that of the main reinforcing bars 11. Specifically, the upper end of the reinforcing reinforcing bar 12 is in the joint 24, but is slightly lower than the position of the fixing plate 14, and the lower end of the reinforcing reinforcing bar 12 is the column 22 below the joint end face 24a. Located in. Note that the joint end face 24a is a boundary between the joint 24 and the column 22, and corresponds to a portion obtained by extending the lower side surface of the beam 23 in the horizontal direction as indicated by a dotted line in FIG.

  As described above, the main reinforcing bar 11 and the reinforcing reinforcing bar 12 are arranged close to each other in parallel and overlap each other over a predetermined range in the extending direction of the column 22. Therefore, similarly to the stress transmission mechanism in the reinforced steel lap joint used in the general RC structure, in the overlapped portion, the tensile force received by the main reinforcing bar 11 is caused by the adhesive force with the surrounding concrete 21. , Transmitted to the reinforcing steel bars 12 In the example shown in FIG. 6, the overlapping range of the main reinforcing bar 11 and the reinforcing reinforcing bar 12 includes a first range A1 below the joint end surface 24a and a second range A2 above the joint end surface 24a. Is included. The length of the first range A1 as the essential overlap range is set to be longer than the length necessary for transmitting the tensile force received by the main reinforcing bar 11 to the reinforcing reinforcing bar 12. The length of the second range A2 as the necessary fixing range is the length of the reinforcing bar used in a general RC structure, that is, the tensile force received by the reinforcing reinforcing bar 12 is transmitted to the surrounding concrete 21. It is set to be equal to or longer than the necessary fixing length, which is a length necessary for this.

According to the 2010 RC standard, in general, the fixing length of the reinforcing bar is L, the diameter of the reinforcing bar is D, the short-term tensile strength of the reinforcing bar is ft, and the strength that is the reference for the reinforcing split of the reinforcing bar is fa, the structural member When the correction factor by S is S and the correction factor for the lateral reinforcement is α, the required fixing length is L = (S × α × ft × D) / 10fa
It has been proposed to

  Moreover, the length of the lap joint of the reinforcing bar used in the RC structure is generally 40D or more, where D is the diameter of the reinforcing bar.

  When an external force F such as seismic force is applied to the column 22, the main reinforcing bar 11 receives a tensile force, and the surface of the main reinforcing bar 11 adheres to the surrounding concrete 21. The applied force P3 is transmitted from the main reinforcing bar 11 to the concrete 21. Further, since the tensile force received by the main reinforcing bar 11 is transmitted to the reinforcing reinforcing bar 12, the adhesion force P <b> 3 is also transmitted from the reinforcing reinforcing bar 12 to the concrete 21. In FIG. 6, for convenience of illustration, arrows are provided only around the main reinforcing bar 11 and the reinforcing reinforcing bar 12 located on the left side of the column 22, but the main reinforcing bar 11 and the reinforcing member located on the right side of the column 22 are provided. Also from the reinforcing bar 12, the adhesive force P3 is transmitted to the concrete 21.

  Since the tensile force received by the main reinforcing bar 11 is transmitted to the reinforcing reinforcing bar 12 by overlapping with the reinforcing reinforcing bar 12, the tensile force received by the main reinforcing bar 11 is reinforced in the overlapping range and the range above it. It decreases compared with the case where it does not overlap with the reinforcing bar 12. As a result, the tensile force received by the fixing plate 14 attached to the tip of the main reinforcing bar 11 is also reduced, so that the supporting pressure transmitted from the fixing plate 14 to the concrete 21 is also reduced. Further, the adhesion force P3 transmitted from the main reinforcing bar 11 near the fixing plate 14 to the concrete 21 is also reduced. Therefore, even if the shortest distance from the surface of the fixing plate 14 to the surface 21a of the concrete 21 is small, no crack is generated in the cover portion near the fixing plate 14.

  In the comparative example shown in FIG. 7, the reinforcing reinforcing bars 12 that overlap the main reinforcing bars 11 do not exist. Therefore, the tensile force received by the main reinforcing bar 11 remains large without decreasing, the tensile force received by the fixing plate 14 is also large, and the support pressure transmitted from the fixing plate 14 to the concrete 21 is large. Further, the adhesive force P3 transmitted from the main reinforcing bar 11 near the fixing plate 14 to the concrete 21 is also large. Therefore, since the large supporting pressure and the large adhesion force P3 are transmitted to the concrete 21 in the cover portion near the fixing plate 14, the concrete 21 is destroyed in the region 26.

  Moreover, the distortion | strain of the main reinforcement 11 produced by receiving a tensile force is distributed as shown by (epsilon). As can be seen from the strain distribution shown in FIG. 7, the portion where the strain becomes the maximum value εmax is directly under the joint end face 24a. When the external force F is large and the tensile force received by the main reinforcing bar 11 is large, there is a high probability that the main reinforcing bar 11 will yield at a point where the strain becomes the maximum value εmax. That is, the yield location 11a of the main reinforcing bar 11 is directly below and in the vicinity of the joint end face 24a. And if the main reinforcement 11 yields in tension, damage will occur in the concrete 21 around the yield location 11a, so the damage occurrence location 25 is directly below and near the joint end face 24a. Therefore, there is a possibility that breakage may occur at the joint 24 or the beam 23 prior to the column 22.

  On the other hand, if there is a reinforcing reinforcing bar 12 that overlaps with the main reinforcing bar 11, the tensile force received by the main reinforcing bar 11 is transmitted to the reinforcing reinforcing bar 12, so that the strain distribution of the main reinforcing bar 11 caused by receiving the tensile force is distributed. ε is as shown in FIG. That is, the portion where the strain becomes the maximum value εmax is guided from directly below the joint end face 24a, that is, closer to the center of the span of the column 22, and corresponds to the vicinity of the lower end of the first range A1. Become. Along with this, the damage occurrence location 25 is also guided toward the center of the span of the column 22 and becomes a location corresponding to the lower end of the first range A1. Thereby, the deformation | transformation performance of the reinforced concrete structure 20 designed so that the pillar 22 may destroy before another member improves. The length of the first range A1 is longer than the length necessary for transmitting the tensile force received by the main reinforcing bar 11 to the reinforcing reinforcing bar 12, and more than the length necessary for guiding the damage occurrence location 25. Is set.

  As described above, the reinforced concrete structure 20 in the present embodiment includes the concrete 21, the main reinforcing bar 11 embedded in the concrete 21, and the reinforcing reinforcing bar embedded in the concrete 21 with at least a portion overlapping the main reinforcing bar 11. 12, the main reinforcing bar 11 includes a fixing plate 14 attached to the tip, and the reinforcing reinforcing bar 12 is in a first range A1 that is longer than the length necessary for transmitting the tensile force received by the main reinforcing bar 11. It extends alongside the main rebar 11 inside the main rebar 11. As a result, at least a part of the tensile force received by the main reinforcing bar 11 is transmitted to the reinforcing reinforcing bar 12, so that the supporting pressure transmitted from the fixing plate 14 to the concrete 21 is also transmitted from the main reinforcing bar 11 to the concrete 21. Therefore, even if the mechanical fixing method is employed, the concrete 21 is effectively prevented from being broken at the cover portion in the vicinity of the fixing plate 14. Moreover, since the damaged part of the concrete 21 resulting from the yielding of the main reinforcing bar 11 is guided toward the center of the span of the column 22, the deformation performance of the column 22 designed to break before other members is improved. It becomes possible.

  The main reinforcing bar 11 extends linearly in the extending direction of the column 22, the fixing plate 14 is located in the joint portion 24 between the column 22 and the beam 23, and the first range A1 is a joint portion end surface 24 a. On the side of the column 22, the reinforcing reinforcing bars 12 are in a range extending linearly in close proximity to the main reinforcing bars 11.

  Further, when the main reinforcing bar 11 receives a tensile force, the strain generated in the main reinforcing bar 11 is the maximum near the end of the first range A1 and on the side opposite to the joint end face 24a. Therefore, when the tensile force received by the main reinforcing bar 11 is large, the yielding point 11a and the damage occurrence point 25 of the main reinforcing bar 11 are guided toward the center of the span of the column 22, and are the end of the first range A1 and the end face of the joint portion. It is in the vicinity of the end opposite to 24a. Thereby, the deformation | transformation performance of the pillar 22 designed to destroy prior to another member improves.

  Further, the reinforcing reinforcing bars 12 extend outside the first range A1 over the second range A2 longer than the length necessary for transmitting the tensile force received from the main reinforcing bars 11 to the surrounding concrete 21. . Note that the second range A2 is a range in which the reinforcing reinforcing bars 12 extend in a straight line in parallel to the main reinforcing bars 11 on the side of the joint 24 on the joint end face 24a. Therefore, the reinforcing steel bars 12 are securely fixed to the concrete 21.

  Next, a second embodiment will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operation and the same effect as those of the first embodiment is also omitted.

  FIG. 8 is a schematic cross-sectional view of a reinforced concrete structure according to the second embodiment.

  In the present embodiment, a part of the reinforcing reinforcing bar 12 is curved. Specifically, the portion corresponding to the second range A2 on the upper side of the joint end face 24a in the reinforcing reinforcing bar 12 has a bending inner radius of 10φ (φ is the diameter of the reinforcing reinforcing rod 12) or more. The portion corresponding to the first range A1 on the lower side of the joint end face 24a in the reinforcing reinforcing bar 12 is a straight line parallel to the main reinforcing bar 11 inside the main reinforcing bar 11, as in the first embodiment. It is a straight line that extends.

This is because, for example, when the reinforcing bar 12 has a large force, or when the beam 23 has a small dimension in the height direction and a straight line cannot secure the required fixing length, the reinforcing bar 12 has This is because the portion corresponding to the second range A2 can be included in the fixing length by curving the portion corresponding to the second range A2 to have a bending inner radius of 10φ or more (for example, Non-Patent Document 5). reference.).
Railway Technical Research Institute, “Railway Structure Design Standards / Explanation Concrete Structure”, 2004.4

  The configuration, operation, and effects of other points of the reinforced concrete structure 20 are the same as those in the first embodiment, and thus the description thereof is omitted.

  As described above, in the reinforced concrete structure 20 according to the present embodiment, the second range A2 is a range in which the reinforcing reinforcing bars 12 are curved and extend on the joining portion 24 side of the joining portion end surface 24a. In the second range A2, the reinforcing reinforcing bars 12 are curved so that the bending inner radius is 10 times or more of the diameter. Thereby, for example, even when the force that the reinforcing reinforcing bar 12 is responsible for is large, or even when the height 23 of the beam 23 is small and the straight reinforcing bar cannot secure the necessary fixing length, the reinforcing reinforcing bar 12 can be secured. Is firmly fixed on the concrete 21.

  It should be noted that the disclosure of the present specification describes features related to preferred and exemplary embodiments. Various other embodiments, modifications and variations within the scope and spirit of the claims attached hereto can naturally be conceived by those skilled in the art by reviewing the disclosure of this specification. is there.

  The present disclosure can be applied to a reinforced concrete structure.

DESCRIPTION OF SYMBOLS 11 Main reinforcement 12 Reinforcement reinforcement 14 Fixing plate 20 Reinforced concrete structure 21 Concrete 22 Column 23 Beam 24 Joint part 24a Joint part end surface

Claims (7)

Comprising concrete, an axial rebar embedded in the concrete, and a reinforcing rebar embedded in the concrete at least partially overlapping with the axial rebar,
The axial rebar includes a mechanical fixing member attached to the tip;
The reinforcing reinforcing bar extends alongside the axial reinforcing bar on the inner side of the axial reinforcing bar over an essential overlap range longer than a length necessary for transmitting the tensile force received by the axial reinforcing bar. A reinforced concrete structure characterized by The axial rebar extends linearly in the direction of extension of the column;
The mechanical fixing member is located in a joint between the column and the beam;
2. The reinforced concrete structure according to claim 1, wherein the essential overlap range is a range in which the reinforcing reinforcing bars are linearly extended in parallel with each other in the vicinity of the axial reinforcing bars on the column side of the joint end face.   3. The strain generated in the axial rebar when the axial rebar is subjected to a tensile force is maximized in the vicinity of the end of the essential overlap range and the end opposite to the joint end surface. Reinforced concrete structure.   The reinforcing reinforcing bar extends over a necessary fixing range longer than a length necessary for transmitting a tensile force received from the axial reinforcing bar to surrounding concrete outside the essential overlap range. 4. The reinforced concrete structure according to any one of items 3.   5. The reinforced concrete structure according to claim 4, wherein the necessary fixing range is a range in which the reinforcing reinforcing bars linearly extend parallel to each other in the vicinity of the axial reinforcing bars on the joint side of the joint end face.   5. The reinforced concrete structure according to claim 4, wherein the necessary fixing range is a range in which the reinforcing reinforcing bar is curved and extends on a joint portion side of a joint portion end face.   7. The reinforced concrete structure according to claim 6, wherein, in the necessary fixing range, the reinforcing reinforcing bars are curved so that an inner radius of bending is 10 times or more of a diameter.