JP4716311B2 - Method for reinforcing joints of precast reinforced concrete members - Google Patents

Description

  The present invention relates to a method for reinforcing a joint portion of a precast reinforced concrete member.

  In the PCa construction method in which a building is constructed using a precast reinforced concrete member (in the following description, “precast reinforced concrete” is expressed as “PCa”), the PCa member manufactured at the factory is transported to the site. Join the reinforcing bar of the member to the reinforcing bar of another PCa member, or join the reinforcing bar of the cast-in-place concrete placement part, and cast the cast-in-place concrete into the joint part, or grout, etc. The curable filler is filled.

  Moreover, in this PCa construction method, when joining two precast reinforced concrete members to each other or joining a precast reinforced concrete member to an existing cast-in-place concrete placement part, both concrete surfaces are brought close to each other and face each other. It is also done to join them. In that case, joining of these reinforcing bars is performed using a grout filling type reinforcing bar joint. Further, a joint space is defined in a narrow joint portion between the two concrete surfaces that are close to each other and face each other, and the joint space is filled with a curable filler such as grout. The filled grout is cured to form a grout layer. In determining the design value of the thickness of the grout layer, that is, the joint width, it is necessary to consider the filling properties when filling the grout in the joint space and the strength of the grout layer after curing.

  The smaller the joint width, the more advantageous in terms of economy and strength. However, if the joint width is too small, the grout to be filled may not be able to sufficiently rotate around the entire joint space, and a gap may remain, and the strength of the joint portion may be reduced due to a cross-sectional defect. A thin grout layer defined with a reduced joint width is generally prone to cracking. The crack of the grout layer is more likely to occur in the outer peripheral portion, that is, the portion where the joint is exposed than in the central portion of the joint portion. In particular, if a crack in the grout layer appears to occur at a joint portion located at a high place such as a stigma, there is a concern that the fragment of the cracked grout may be peeled off and dropped.

  Therefore, when precast reinforced concrete is joined, when determining the joint width design value of joints defined between concrete surfaces that are close to each other and facing each other, the joint width is determined by the curability of grout and the like. It is necessary to satisfy both the condition that the filler should be wide enough to allow good filling and the condition that the cured filler layer must be narrow enough to have sufficient strength.

  However, when the PCa construction method is applied to a high-rise building, for example, and the joint portion between the column base and the top of the PCa column member is a narrow joint portion that defines the joint space as described above, these 2 It becomes difficult to satisfy both conditions. This is because, in this type of building, since the pillars are thick, the area of the joining portion becomes large. Therefore, in order to ensure good filling properties, it is necessary to set a wider joint width. On the other hand, in this type of building, since the axial compressive load acting on the column is large, it is required to set the joint width narrower in order to ensure the strength of the filler layer after curing. These conflicting requirements make it difficult to satisfy the above two conditions.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a joint area of a large area when the joint part of the PCa member is a narrow joint part that defines a joint space. Even if it is a thing, the joint part of the PCa member is reinforced so that the joint part can be satisfactorily filled with the curable filler, and the cured filler layer can have sufficient strength. Therefore, it is to prevent cracking and peeling of the filler after curing.

In order to achieve such an object, a method for reinforcing a joint portion of a precast reinforced concrete member according to the present invention is a precast method in which the concrete surfaces of two precast reinforced concrete members are brought close to each other and face each other and the precast reinforced concrete members are joined to each other. In the method for reinforcing a joint portion of a reinforced concrete member , a joint space is defined around the center of the concrete surface between the concrete surfaces of two precast reinforced concrete members that are close to each other and face each other, and the joint space includes the joint space. A mesh material extending along the joint space is disposed only around the entire periphery of the joint space, and then the curable filler is filled into the joint space and cured.

Further, the method for reinforcing the joint portion of the precast reinforced concrete member according to the present invention is such that the concrete surface of the existing cast-in-place concrete placement portion and the concrete surface of the precast reinforced concrete member are brought close to each other to face each other, to the time of joining the precast reinforced concrete element, in the method of reinforcing the bonding portions of the precast reinforced concrete element, which concrete between the existing cast-in-place concrete provided portion of the concrete surface and the precast reinforced concrete of the concrete surface to be opposed in close proximity to each other A joint space is defined around the central portion of the surface, and a mesh material extending along the joint space is disposed only in the periphery of the joint space in the joint space. Fill with curable filler Wherein the curing.

  According to the method for reinforcing the joint portion of the PCa member according to the present invention, since the filler layer after curing is reinforced by the mesh material, when the joint portion of the PCa member has a large area, accordingly, The joint width can be set wide, so that the curable filler can be satisfactorily filled into the joint portion, and the cured filler layer can have sufficient strength, It is possible to satisfactorily prevent the filler from cracking or peeling off.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1A is an elevation view showing a concrete example of a PCa column member and a PCa column beam joint block that reinforce a joint portion using the reinforcing method according to the present invention together with the PCa beam member, and FIG. It is a top view of the PCa column beam junction block and PCa beam member shown to (A). 2 (A) and 2 (B) show a joint portion between the column head of the PCa column member and the PCa column beam joint block of FIG. 1 to which the method according to the first embodiment of the present invention is applied. It is a sectional elevation view and a plan view. 1 and 2, the upper surface of the stigma of the PCa column member 10 defines a horizontal plane, and the upper ends of the plurality of column main bars 12 extend upward from the upper surface of the stigma. The PCa beam-column joint block 14 is formed by integrating the beam-column joint 16 and the beam 18 extending laterally from the beam-column joint 16 into a PCa member. As shown in FIGS. 1A and 1B, the tip of the PCa beam member 19 is joined. As shown in FIGS. 2 (A) and 2 (B), the upper ends of a plurality of column main bars 12 extending from the column head of the PCa column member 10 are formed on the column beam junction 16 of the PCa column beam junction block 14. A plurality of column main reinforcement insertion holes 20 for insertion are formed through. The central portion of the lower surface of the beam-column joint 16, the convex Cotter 22 are projectingly formed a projection of flat truncated quadrangular pyramid shape. In the illustrated example, the column main bar insertion hole 20 is formed by embedding a sheath tube 24 in the column beam joint 16.

In order to join the PCa column beam joint block 14 to the column head of the PCa column member 10, the upper ends of the plurality of column main bars 12 extending upward from the upper surface of the column head of the PCa column member 10 are connected to the PCa column beam junction block. The PCa column beam joint block 14 is placed on the stigma of the PCa column member 10 through the plurality of column main bar insertion holes 20. At this time, the convex cotter 22 on the lower surface of the beam-column joint portion 16 of the PCa beam-column joint block 14 abuts on the upper surface of the column head of the PCa column member 10, so that the lower surface of the beam-column joint portion 16 and the PCa column member 10 A joint space 26 is formed around the convex cotter 22 (center portion) between the upper surface of the stigma. Therefore, by placing the PCa beam-column joint block 14 on the column head of the PCa column member 10, the concrete surface on the lower surface of the PCa beam-column joint block 14 and the concrete surface on the upper surface of the column head of the PCa column member 10 Are close to each other and face each other, and a joint space 26 is defined there.

  In the present invention, a mesh material 28 extending along the joint space 26 is disposed in the joint space 26, and the mesh material 28 is a filler layer made of a curable filler described later. It is intended to reinforce. The mesh material 28 is preferably made of a metal net material, and preferably has a planar shape extending along the peripheral edge of the joint space 26 as shown in FIG. .

  As a work procedure at the time of joining, first, a plurality of spacers 30 are placed on the upper surface of the stigma of the PCa pillar member 10, and the spacers 30 are arranged between a mesh material 28 and the concrete surface of this stigma. This is for securing the interval. Subsequently, the mesh material 28 is placed on the spacers 30 so as to pass the column main reinforcement 12 through the mesh of the mesh material 26. After that, the PCa column beam joint block 14 is placed on the column head of the PCa column member 10.

  Subsequently, the periphery of the joint space 26 formed by placing the PCa column beam joint block 14 is sealed with a retaining frame 31 made of a filler. Thereafter, the joint space 26 and the pillar main bar insertion hole 20 are filled with a grout which is a curable filler and cured. The filling into the joint space 26 and the filling into the pillar main bar insertion hole 20 may be performed separately or simultaneously. Further, in order to fill the joint space 26 with the grout, an injection hole may be formed in the stop frame 31 and the grout may be injected from the injection hole. Alternatively, the grout may be injected into the PCa beam-column joint block 14. A hole may be formed to penetrate and grout may be injected from the injection hole. In addition, it is also possible to use things other than grout as the curable filler.

  As the filled grout is hardened, the PCa column beam joint block 14 and the PCa column member 10 are fixedly joined. In particular, since the grout layer formed by hardening the grout filled in the joint space 26 is reinforced by the mesh material 28, the joint width is set relatively wide to increase the thickness of the grout layer. Even in this case, shear cracking does not occur due to a large compressive load due to an earthquake or the like, and it can have sufficient strength to withstand the compressive load. Therefore, when the PCa column member 10 is relatively thick and the joint portion with the PCa column beam joint block 14 has a large area, it is sufficient to ensure a good filling property by setting the joint width wide. There is no shortage of strength in the grout layer. Moreover, the mesh material 28 having a planar shape extending along the peripheral edge of the joint space 26 reinforces the peripheral edge of the joint portion where a greater compressive stress acts than the central portion of the joint portion. It is reasonable.

  FIGS. 3A and 3B show a joint portion between a column base of a PCa column member to which a method according to a second embodiment of the present invention is applied and a floor slab that is a cast-in-place concrete placing portion. It is a sectional elevation view and a plan view. In FIG. 3, the upper surface of the floor slab 32 defines a horizontal plane, while a convex cotter, which is a flat quadrangular pyramid-shaped protrusion, is formed at the center of the lower surface of the column base of the PCa column member 34. 36 is protrudingly formed.

When the column base of the PCa column member 34 is placed on the upper surface of the floor slab 32, the convex cotter 36 on the lower surface of the column base of the PCa column member 34 comes into contact with the upper surface of the floor slab 32. A joint space 38 is formed around the convex cotter 36 (central portion) between the lower surface of the floor slab 32 and the upper surface of the floor slab 32. The upper concrete surface is brought close to and opposed to each other, and a joint space 38 is defined there.

  In the embodiment shown in FIG. 3, as in the embodiment shown in FIG. 2, the mesh material 40 extending along the joint space 38 is arranged in the joint space 38. The mesh material 40 is the same as the mesh material 28 shown in FIG.

  The work procedure at the time of joining is the same as that of the embodiment shown in FIG. 2. First, a predetermined interval is secured on the upper surface of the floor slab 32 between the mesh material 40 and the upper surface of the floor slab 32. A plurality of spacers 42 are placed, the mesh material 40 is placed on the spacers 42, and then the PCa column member 34 is placed on the upper surface of the floor slab 34. Subsequently, the periphery of the joint space 38 formed by placing the PCa pillar member 34 is sealed with a filler retaining frame 44, and the joint space 38 is filled with grout as a curable filler. Harden. Also in the joint portion reinforcing method according to the second embodiment, the same advantage as that of the first embodiment can be obtained by reinforcing the grout layer after curing by the mesh material 40.

  4 (A) and 4 (B) are side views of a mesh material 46 according to a modified example that can be used in place of the mesh materials 26 and 40 of FIGS. 2 and 3 described above. It is a top view. The mesh material 46 of FIG. 4 differs from the mesh materials 26 and 40 described above only in that the mesh material 46 has a peripheral bent portion, and the other portions are the same as the mesh materials 26 and 40. is there. The peripheral bent portion of the mesh material 46 has the function of the spacers 30 to 42 (function of ensuring a predetermined interval between the mesh material and at least one concrete surface of two concrete surfaces defining the joint space). In the case of using this mesh material 46, it is not necessary to provide a spacer.

(A) is the elevation which showed the concrete example of the PCa column member which reinforces a joined part using the reinforcing method concerning the present invention, and a PCa column beam joint block with a PCa beam member, (B) is (A) It is a top view of the PCa column beam junction block and PCa beam member shown in FIG. (A) And (B) is sectional elevation which showed the junction part of the column head of the PCa column member of FIG. 1 and the PCa column beam junction block of FIG. 1 which applied the method which concerns on the 1st Embodiment of this invention. FIG. (A) And (B) is a cross-sectional view showing a joint portion between a column base of a PCa column member to which a method according to a second embodiment of the present invention is applied and a floor slab that is a cast-in-place concrete placing portion. It is a surface view and a top view. (A) And (B) is the side view and top view of the mesh material 46 which concern on the example of a change which can be used instead of the mesh materials 26 and 40 of FIG.2 and FIG.3.

Explanation of symbols

  10 ... PCa column member, 14 ... PCa column beam joint block, 26 ... Joint space, 28 ... Mesh material, 32 ... Floor slab, 34 ... PCa column member, 38 ... Joint space, 40 ... ... mesh material, 46 ... mesh material.

Claims (5)

In the reinforcing method of the joint portion of the precast reinforced concrete member when the two precast reinforced concrete members are brought close to each other and face each other and the precast reinforced concrete members are joined to each other,
A joint space is defined between the concrete surfaces of two precast reinforced concrete members that are close to each other and facing each other around the center of the concrete surface,
In the joint space, a mesh material extending along the joint space is disposed only around the peripheral edge of the joint space, and then the curable filler is filled in the joint space and cured.
A method for reinforcing a joint portion of a precast reinforced concrete member, characterized by: The joint portion of the precast reinforced concrete member when the precast reinforced concrete member is joined to the cast-in-place concrete placement portion with the concrete surface of the existing cast-in-place concrete placement portion and the concrete surface of the precast reinforced concrete member in close proximity to each other In the reinforcing method of
A joint space is defined around the center of the concrete surface between the concrete surface of the existing cast-in-place concrete placement part and the concrete surface of the precast reinforced concrete that are close to each other and face each other ,
In the joint space, a mesh material extending along the joint space is disposed only around the peripheral edge of the joint space, and then the curable filler is filled in the joint space and cured.
A method for reinforcing a joint portion of a precast reinforced concrete member, characterized by:   The method for reinforcing a joint portion of a precast reinforced concrete member according to claim 1 or 2, wherein the mesh material is made of a metal net material.   When arranging the mesh material in the joint space, for securing a predetermined interval between the mesh material and at least one concrete surface of two concrete surfaces defining the joint space. The method for reinforcing a joint portion of a precast reinforced concrete member according to claim 1 or 2, wherein a spacer is provided.   As the mesh material, use a mesh material in which a peripheral bent portion for securing a space between the mesh material and at least one concrete surface of the two concrete surfaces defining the joint space is formed. A method for reinforcing a joint portion of a precast reinforced concrete member according to claim 1 or 2.

Images