JP4642373B2 - Concrete member joint structure - Google Patents

Description

  The present invention relates to a joint structure for a concrete member that suppresses damage such as cracking and crushing of concrete in one concrete member and buckling of a reinforcing bar in a joint portion between two concrete members to be joined together.

For example, at a joint between a reinforced concrete column member and a beam member, as a method of suppressing damage such as cracking or crushing of the concrete after the main beam yields during a large earthquake, a part of the main beam bar is insulated from the concrete. There is a method for improving the elongation deformation capability of the beam main bar by preventing the adhesion splitting fracture due to adhesion with concrete (see Patent Document 1 and Patent Document 2).
Japanese Patent Laid-Open No. 5-5342 Japanese Unexamined Patent Publication No. 9-111865

  As described above, cutting the adhesion of the section of the beam reinforcement near the column member to the concrete can prevent the beam member from being destroyed after the hinge is formed at the beam end, but the beam member itself Since the resistance to bending moments and shear forces is reduced, the hinged portion of the beam member can no longer maintain the same proof strength as the portion that is not hinged.

  In view of the above background, the present invention proposes a joint structure that suppresses a decrease in yield strength against bending moment and shearing force of a hinge forming portion and damage to concrete.

In the present invention, as shown in FIG. 1 and FIG. 3, of the two concrete members A and B joined to each other, the main reinforcement 1 arranged in the material axis direction in one concrete member A and the other concrete member B The joint bar 2 is arranged to be extended to one concrete member A while being fixed, and the main bar 1 is arranged at least to the boundary surface with the other concrete member A, and the joint bar 2 is In one concrete member A, it is paired in the composition direction or width direction, and in the state of crossing each other , it is diagonally arranged toward the central part of the member composition, and in the section farther from the other concrete member, By adhering, and not adhering to the concrete in the section near the other concrete member, damage such as cracking and crushing of the concrete member A can be suppressed, and the bending mode can be reduced. Suppressing a decrease in resistance to placement and shearing forces, together reduces the shear forces that the concrete be borne by.

  In the drawing, a portion indicated by a thick line in the joint line 2 indicates a section where the adhesion with concrete is cut (a section without adhesion). A state in which the joint line 2 is not attached to the concrete (cutting off the adhesion of the joint part 2) can be obtained by applying grease to the joint part 2 or covering it with a cloth or a sleeve, but the method is not limited.

  For example, when a load (shearing force) in a direction perpendicular to the material axis is applied to one concrete member A in a cantilever state as shown in FIG. 2- (a), one concrete member A is deformed in the direction in which the load is applied. Attempt is made and the joint muscle 2 on the tension side bears the tensile force.

  At this time, while the joint line 2 is fixed in the other concrete member B, it adheres to the concrete in a section farther than the other concrete member in one concrete member A, and becomes concrete in the section near the other concrete member B. By not sticking, the joint 2 on the tension side follows the deformation of one concrete member A in the section where there is adhesion with the concrete (section where there is adhesion), and causes elongation deformation in the section where there is no adhesion. It reaches. The deformation of the concrete member during yielding can be freely set by adjusting the length of the section where there is no adhesion.

  In contrast to the case where the joint muscle 2 is completely adhered in one of the concrete members A by causing elongation deformation in the section where the joint muscle 2 is not attached, the joint muscle is produced in the section where the adhesion is cut. Since the shearing force and the bending moment in the concrete member A excluding the joint portion 2 are reduced by the tensile force and the compressive force borne by 2 compared to the case where there is adhesion, damage to the concrete due to the shearing force and the bending moment is reduced. The

  In addition, as shown in FIG. 2- (a), the joint line 2 adheres to the concrete in the section near the intersection in one concrete member A and does not adhere to the concrete in the section near the other concrete member B. Since a reaction force is generated in the section attached to the shear force, and the component of the reaction force in the direction perpendicular to the material axis resists the shear force, the one of the concrete members A as shown in FIG. The shearing force acting on the portion excluding the joint line 2 is also reduced, and the shear failure of the concrete at the end of one concrete member A is suppressed.

  In addition, the component in the material axis direction of the reaction force in the attachment section of the joint muscle 2 shown in FIG. 2A forms a couple of bending back to the bending moment due to the shearing force. The effect of reducing and reducing the damage of the concrete in the hinge part of one concrete member A is exhibited. It can be seen that cracking and crushing at the end of one concrete member A are suppressed from the effect of reducing the bending moment by bending back.

  In addition, for example, as shown in FIG. 12 of Patent Document 2, the main bar 1 corresponding to the beam main bar 7 of Patent Document 2 is arranged only up to the section where the joint bar 2 corresponding to the beam main bar 5 of Patent Document 2 is attached. If the adhesion of the joint reinforcement 2 to the concrete in the section near the other concrete member B is cut, the reinforcement corresponding to the main reinforcement of the reinforced concrete structure integrated in the section without the joint reinforcement 2 attached. In the section where there is no adhesion, resistance occurs only with concrete, so that the resistance to bending moment and shearing force of one concrete member A decreases.

  On the other hand, in the present invention, the main reinforcement 1 of one concrete member A is arranged at least to the boundary surface with the other concrete member B, and the main reinforcement 1 adheres to the surrounding concrete to the boundary surface. Since the main bar 1 integrated with the concrete exists in the section where the joint reinforcement 2 is cut off in one concrete member A (the section without adhesion), the hinge is formed at the hinge forming portion of the one concrete member A. It is possible to provide resistance to bending moments and shearing forces similar to those of the portions that do not form.

  That is, in the section where the joint reinforcement 2 is not attached, the main reinforcement 1 and the surrounding concrete are integrated by the adhesive force between the two, so that the same stress is applied to the portion where the hinge is not formed between the main reinforcement 1 and the concrete. It can be transmitted by wearing force.

  As shown in FIG. 1, the joint bar 2 is partially arranged only at the end of one concrete member A near the other concrete member B, and is arranged over the entire length as shown in FIG. There is a case where it is streaked (Claim 2), and it is properly used according to the parts of both concrete members A and B. In the latter case, the joint bars 2 intersect with each other at the central portion in the material axis direction of one concrete member A.

  Since the main reinforcement 1 of one concrete member A of the present invention only needs to be arranged up to at least the boundary surface with the other concrete member B, the other concrete member B depends on the location of the concrete members A and B as shown in FIG. There is a case where it stays at the boundary surface between the two and the other concrete member B as shown in FIG.

  According to claim 3 in which the main reinforcement 1 of one concrete member A is arranged to the inside of the other concrete member B, the damage of the hinge portion is increased compared with the case where it stays at the boundary surface, but the load of the tensile force acting on the main reinforcement 1 is increased. Since the capacity increases, the resistance force against the bending moment of one concrete member A increases.

  In claim 3 where the main reinforcing bar 1 is arranged to the inside of the other concrete member B, as shown in FIG. 4, the main reinforcing bar 1 is completely adhered to the concrete inside the other concrete member B, and the hinge part is damaged. In order to reduce the above, as shown in FIG. 5, there is a case where a part of the section near the one concrete member A is not adhered to the concrete inside the other concrete member B (claim 4). FIG. 6 shows a special case of claim 4 in which the main reinforcement 1 is not attached to the concrete in the entire section inside the other concrete member B (claim 5). FIG. 7 shows the case where the joint bars 2 are arranged over the entire length of one concrete member A (Claim 2).

  According to the fourth aspect of the present invention, the main reinforcement 1 can yield in the section where the adhesion has been cut. Therefore, the concrete member A can be deformed with little damage.

  In particular, as described in claim 5, if the main reinforcement 1 is not attached to the concrete in the entire section inside the other concrete member B, the entire section of the main reinforcement 1 inside the other concrete member B is stretched and deformed. Since no tensile stress is generated, the function (the dowel action) in which the main reinforcing bar 1 transmits to the other concrete member B with respect to the shearing force in the direction perpendicular to the material axis of one concrete member A is sufficiently exhibited. be able to.

  While being fixed in the other concrete member, the joint bar which is extended to one concrete member and placed is obliquely arranged in the one concrete member toward the center of the member, and the other By adhering to the concrete in the section far from the concrete member and not adhering to the concrete in the section close to the other concrete member, the load of the joint muscle of one concrete member against the load (shearing force) in the direction perpendicular to the material axis It is possible to cause elongation deformation in a section where there is no adhesion with concrete, and it is possible to bear a greater tensile force when the joint reinforcement is completely attached. It is possible to reduce the tensile stress to be borne by the removed concrete and to suppress cracks accompanying it.

  In addition, while the joint line is fixed in the other concrete member, it adheres to the concrete in the section far from the other concrete member in one concrete member, and does not adhere to the concrete in the section near the other concrete member. A reaction force against the shearing force is generated in the section, and the component of the reaction force in the direction perpendicular to the material axis resists the shearing force, so the shearing force acting on the part of one concrete member excluding the joint is also reduced. In addition, it is possible to prevent the shear failure of the concrete at the end of one concrete member.

  The component in the material axis direction of the reaction force in the bonded section of the joint line forms a couple of bending back to the bending moment due to the shearing force, thus reducing the bending moment due to the shearing force and at the hinge part of one concrete member It also has the effect of reducing concrete damage.

  In addition, the main reinforcement of one concrete member is arranged to at least the boundary surface with the other concrete member, and the main reinforcement adheres to the surrounding concrete up to the boundary surface, so that one concrete member of the joint reinforcement Since there is a main reinforcement united with concrete in the section where the adhesion is cut, the hinge forming part of one concrete member can have the same resistance to bending moment and shear force as the part not forming the hinge. It is possible, and in the section where the joint bars do not adhere, the same stress as that of the portion where no hinge is formed between the main bars and the concrete can be transmitted by the adhesive force.

  In claim 3, by placing the main reinforcement of one concrete member to the inside of the other concrete member, the load capacity of the tensile force acting on the main reinforcement is increased as compared with the case of staying at the boundary surface. The resistance to the moment can be increased.

  In claim 4, the main bar can yield in the section where the adhesion is cut by not attaching the part of the main bar close to at least one concrete member inside the other concrete member, so that the main bar can yield. Can be deformed with little damage, and damage to the hinge portion of the other concrete member can be reduced.

  According to claim 5, the main reinforcing bar is not attached to the whole concrete section inside the other concrete member, so that the whole main section inside the other concrete member is not stretched and deformed, and tensile stress is also generated. Therefore, a function of transmitting a shearing force in a direction perpendicular to the material axis of one concrete member A to the other concrete member without applying a tensile force to the section inside the one concrete member A of the main reinforcement (the dowel) Action).

  As shown in FIG. 1 and FIG. 3, the present invention includes a main bar 1 arranged in the direction of the axis of material in one concrete member A, and a concrete member B on the other side. It is extended to one concrete member A while being fixed inside, and using two joint bars 2 along the main bars 1 in the one concrete member A and arranged in one concrete member A, two concretes are used. This is a joint structure formed by joining members A and B. The main reinforcing bars 1 are mainly arranged in one concrete member A in pairs in the forming direction or width direction, and the joint bars 2 are mainly paired in the forming direction or width direction of one concrete member A. It will be arranged.

  The main reinforcement 1 is arranged at least up to the boundary surface with the other concrete member B, the joint reinforcement 2 is arranged obliquely toward the central portion of the member in one concrete member A, and the other concrete member B is arranged. It adheres to concrete in a section farther away and does not adhere to concrete in a section near the other concrete member B.

  1 and 3 show a case where the main reinforcement 1 arranged in the concrete member A is stopped at the boundary surface with the concrete member B when the concrete member A is a beam, the concrete member B is a column, or a bearing wall. Show. FIG. 1 shows a case where the joint bars 2 are arranged only at the end of the concrete member A, and FIG. 3 shows a case where the joint bars 2 are arranged over the entire length of the concrete member A (Claim 2). . In any case, the joint bars 2 intersect each other in the section in the concrete member A, but it is not always necessary to intersect in the central part in the section in the concrete member A as shown.

  Concrete members A and B include columns and beams, bearing walls and columns or beams, upper-floor columns and lower-floor columns, columns and foundations, piles and foundations (footings), bearing walls and bearing walls, and flat slabs. Any part may be used as long as it is a concrete member joined to each other such as a slab and a pillar. It may be precast concrete, whether it is made of cast-in-place concrete or precast concrete, and may be prestressed in addition to reinforced concrete, steel reinforced concrete, steel pipe concrete (CFT), or any combination thereof.

  4 to 7 show a case where the main reinforcing bar 1 is arranged beyond the boundary surface with the concrete member B to the inside of the concrete member B (Claim 3). 4 shows a case where the section of the main reinforcement 1 in the concrete member B is fixed in the concrete, and FIG. 5 shows a case where the section of the main reinforcement 1 near the concrete member A in the concrete member B is cut off. ). 6 and 7 show the case where the adhesion with the concrete is cut over the entire section in the concrete member B of the main reinforcement 1 (Claim 5). 6 and 7 show the case where the concrete member A is a beam, the concrete member A can be replaced with a column, and the concrete member B can be replaced with a foundation or a slab.

  In the case of FIG. 6 and FIG. 7, by cutting the adhesion of the entire section in the concrete member B of the main reinforcement 1, for the shearing force in the direction perpendicular to the material axis of the concrete member A in the section in the concrete member B, Since the section where the adhesion is cut in the concrete member B does not stretch and deform and does not yield, the tensile force is not applied to the section of the main reinforcement 1 inside the concrete member A. Moreover, since the section which cut | disconnected adhesion in the concrete member B of the main reinforcement 1 is always kept healthy, the favorable function (dubbing action) which transmits the shearing force from the concrete member A to the concrete member B is exhibited.

It is the elevation which showed the case where the main reinforcement is stopped at the boundary surface with the other concrete member. (a) is an elevational view showing a reaction force generated in a joint line when a shear force is applied to one concrete member, and (b) is a shear force diagram at that time. It is the elevation which showed the case where a joint part reinforcement is arranged over the full length of one concrete member. It is the elevation which showed the case where the main reinforcement was extended to the inside of the concrete member beyond the boundary surface with the other concrete member, and was fixed in the concrete. It is the elevation which showed the case where the main reinforcement was extended to the inside of the concrete member beyond the boundary surface with the other concrete member, and the adhesion of the section near one concrete member in the concrete member was cut. It is the elevation which showed the case where the main reinforcement was arranged to the inside of the other concrete member, and the adhesion with the concrete was cut. It is the elevation which showed the case where the main reinforcement is arranged to the inside of the other concrete member when the joint reinforcement is arranged over the entire length of one concrete member, and the adhesion with the concrete is cut.

Explanation of symbols

A: One concrete member, B: The other concrete member,
1 …… Main muscle, 2 …… Juncture muscle

Claims (5)

Of the two concrete members to be joined to each other, the main reinforcement arranged in the direction of the axis of the material in one concrete member, and being fixed in the other concrete member, is extended to the one concrete member, one of which A joint structure constructed by joining the two concrete members, using joint bars arranged in one concrete member along the principal bars in the concrete members of
The main bars are arranged at least up to the boundary surface with the other concrete member, and the joint bars are paired in the direction of formation or width in the one concrete member, and in the state of crossing each other, Bonding of concrete members that are diagonally arranged toward the center of the concrete, adhere to the concrete in the section farther than the other concrete member in one concrete member, and not to the concrete in the section near the other concrete member Part structure.
  The joint structure of a concrete member according to claim 1, wherein the joint bars are arranged over the entire length of one concrete member.   The joint structure of a concrete member according to claim 1 or 2, wherein the main reinforcing bar is arranged to the inside of the other concrete member.   The joint part structure of a concrete member according to claim 3, wherein a part of the main reinforcement near the one concrete member inside the other concrete member is not attached to the concrete. The joint structure of a concrete member according to claim 4, wherein the entire section of the main reinforcement inside the other concrete member does not adhere to the concrete.

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