JP2018127804A - Beam structure and construction method of beam structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a beam structure capable of inexpensively preventing the slag of concrete from flowing out to a beam side by flowing over a beam bottom form when placing concrete in a column, and easily allowing placing joint of concrete on a vertical placing-joint surface.SOLUTION: A concrete beam 4 is connected to a concrete column 2. The concrete beam 4 is provided with: a preformed concrete body 30 formed in a beam bottom portion of a beam end and extending in a width direction of the beam; and a subsequently formed concrete body 32 formed on an upper surface of the performed concrete body 30 as a placing-joint surface 31. A lower main reinforcement 20 of the beam 4 is driven into the preformed concrete body 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a structure of a concrete beam bonded to a concrete column and a method for constructing the beam.

  Conventionally, in a reinforced concrete building, the strength of concrete may differ between a column and a beam. In this case, it is necessary to prevent the concrete paste (cement paste) from flowing out to the beam side when placing the concrete in the column.

  Patent Document 1 provides a rectangular opening in which a beam floor located at a predetermined distance from the column side is cut off when casting concrete with different properties between the column, the beam, and the slab. The floor of the beam floor that has been cut up is placed with the cut-out rectangular beam floor cutout facing the column side. Further, there is shown a non-stop structure for a concrete joint in which a concrete joint such as an air fence, a formwork lath, or a metal plate is disposed at the concrete joint part.

  Patent Document 2 discloses a concrete damming device that is installed on a formwork for casting concrete. This concrete damming device includes a damming plate composed of a plurality of plate members, and a guide member in which a slit for setting the damming plate in the beam form from the side is formed. .

  In Patent Document 3, when a high-fluidity concrete is to be handed over or added to a vertical surface, a fastening mold frame having a mesh is fixed to the joint or the part to be added, and a steel plate is attached to the back surface of the steel plate while avoiding the main beam of the beam. A method for stopping high-fluidity concrete, in which high-fluidity concrete is driven after application, is shown.

However, the noro stop structure of Patent Document 1 has a problem that it takes a lot of work because an opening is provided in the formwork at the bottom of the beam.
Moreover, in the concrete damming apparatus of patent document 2, since a clearance gap arises between several plate members inserted from the slit, there existed a problem that concrete leaked from the joining surface.
Moreover, in the method for stopping high-fluidity concrete of Patent Document 3, there is a problem that a gap is generated at the cover portion of the beam reinforcing bar at the beam bottom. In order to eliminate this gap, it is necessary to process the steel plate with high accuracy for each joint portion, which is expensive.

Japanese Patent No. 5893793 JP 2004-137893 A JP 2000-27439 A

  In the present invention, when a concrete column is placed, it is possible to prevent at a low cost that the concrete paste (cement paste) flows on the beam bottom formwork and flows out to the beam side. It is an object of the present invention to provide a beam structure and a method for constructing a beam, which can easily cast concrete.

  As a beam structure to be joined to a column, the present inventors provide a preceding concrete body in which a part of the lower main bar of the beam is embedded at the beam bottom portion of the beam end, and a dam is provided on the upper surface of the preceding concrete body. A stop formwork (for example, a buried formwork or a spliced formwork) is installed, and concrete is placed in front of the beam-column joint side with the damming formwork as a boundary, so that it is cast on the beam-column joint side. The inventors have invented the beam structure and the beam construction method of the present invention by focusing on the fact that it is possible to easily and inexpensively prevent the provided concrete nose from flowing out to the beam side.

  The beam structure of the first invention is a structure of a concrete beam (for example, a beam 4 described later) joined to a concrete column (for example, a column 2 described later), and a beam bottom portion at the end of the beam. In addition, a concrete body that extends in the beam width direction (for example, the preceding concrete bodies 30 and 30A described later) and a concrete surface on the preceding concrete body as a joint surface (for example, a joint surface 31 described later) are used. A post-cast concrete body (for example, a post-cast concrete body 32 which will be described later), and the lower main bar (for example, the lower main bar 20 which will be described later) of the beam is used as the preceding concrete body. Or is placed on the preceding concrete body.

  According to the present invention, first, a preceding concrete body is provided at the beam bottom portion at the end of the beam, and then concrete (described later, S2 in FIG. 3) is placed on the column beam joint side on the preceding concrete body. To do. Thereafter, concrete is placed on the beam side above the preceding concrete body, a post-cast concrete body is provided, and a beam is formed. Therefore, when pouring the concrete of the pillar, it is possible to prevent the concrete nose from flowing out to the beam side. Moreover, since the formwork at the bottom of the beam is not processed, the cost is reduced. Further, it is possible to realize a beam structure formed of a preceding concrete body and a post-concrete concrete body that is easily jointed by a vertical joint surface thereon.

A beam construction method according to a second aspect of the present invention is a method for constructing a concrete beam to be joined to a concrete column, and includes a main bar (for example, a lower main bar 20, an upper main bar 21 described later) and a shear of the beam. A step of arranging reinforcing bars (for example, stirrups 22 and 22A described later) (for example, step S11 described later), and placing concrete on the beam bottom portion of the beam end of the beam, For example, a predecessor concrete body 30 described later is formed, and an embedding formwork (e.g., embedding described later) is formed on the inner side of the shear reinforcing bar (e.g., stirrup 22A described later) on the preceding concrete body. And a rod-shaped splicing mold (for example, a splicing mold 56 described later) extending in the vertical direction on the preceding concrete body and outside the shear reinforcement bar. A step (for example, steps S12 to S17 to be described later), and a surface formed by the burying formwork and the joining formwork as a joining surface (for example, a joining surface 31 to be described later). A step of forming concrete on the beam side of the surface to form a post-cast concrete body (for example, a post-cast concrete body 32 to be described later) (for example, step S3 to be described later).
Here, the beam side of the joint surface is the beam center side of the joint surface.

  According to this invention, first, the preceding concrete body is provided at the beam bottom portion of the beam end. Next, a filling formwork and a joining formwork are attached on the preceding concrete body, and the surface composed of the filling formwork and the joining formwork is used as a joining surface, and the column beam joint side. Place concrete in the wall. Thereafter, concrete is cast on the beam side (beam center side) of the joint surface, a post-cast concrete body is provided, and a beam is formed. Therefore, when pouring the concrete of the pillar, it is possible to prevent the concrete nose from flowing out to the beam side. In addition, by installing the preceding concrete body, it is possible to easily and inexpensively prevent the concrete struck placed on the pillar from flowing out to the beam side without processing the form of the beam bottom. Moreover, concrete can be easily handed over by the preceding concrete body and the vertical joint surface thereon.

  According to a third aspect of the present invention, there is provided a method for constructing a beam, in which, before the step of forming the post-cast concrete body, the buried mold form and the joint mold form are used as a joint surface, and the joint side of the pillar side of the joint surface is provided. The method further comprises a step of placing concrete (for example, step S2 to be described later), and in the step of forming the post-cast concrete body, the rod-shaped joint form is removed and then the beam of the joint surface is removed. It is characterized in that concrete is placed on the side to form a post-cast concrete body.

  According to this invention, after removing the joining formwork from the outside of the shear reinforcement, that is, from the cover portion of the shear reinforcement, the concrete is placed on the beam side of the joining surface to form the post-cast concrete body. Therefore, a predetermined cover thickness can be secured for the beam main bar and the shear reinforcement without driving metal that may corrode into the joint surface between the cover part of the beam and the column. In addition, since no metal burying formwork is left in the cover thickness part of the beam, the soundness of the beam concrete can be secured.

  According to the present invention, by providing the preceding concrete body at the beam bottom portion at the beam end, it is possible to easily and inexpensively prevent the concrete nod placed on the column from flowing out to the beam side. It is possible to realize a beam structure formed by a post-cast concrete body cast by the upper vertical joint surface and a method for constructing the beam.

It is a longitudinal cross-sectional view of the junction structure of the pillar and beam which concerns on 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is a schematic flowchart of the construction | assembly method of joining structure (1st Embodiment). It is a detailed flowchart of the construction method of a junction structure (first embodiment). It is the top view explaining the construction method of joining structure, and BB sectional drawing. It is CC sectional drawing and DD sectional drawing of FIG. It is the top view explaining the construction method of joining structure, and EE sectional drawing. It is the top view explaining the construction method of joining structure, and FF sectional drawing. It is a longitudinal cross-sectional view of the junction structure of the pillar and beam which concerns on 2nd Embodiment of this invention. It is a schematic flowchart of the construction method of joining structure (2nd Embodiment). It is a detailed flowchart of the construction method of a junction structure (2nd Embodiment). It is the top view explaining the construction method of junction structure, and GG sectional drawing. It is the top view explaining the construction method of junction structure, and HH sectional drawing.

In the present invention, as a beam structure to be joined to a column, a preceding concrete body is provided at the beam bottom portion at the end of the beam, a buried form is provided on the upper surface of the preceding concrete body, and the cover thicknesses on both sides of the beam main bar are provided. This is a beam structure and a beam construction method in which a joint form is provided at a portion to prevent a concrete nose placed on a column from flowing out to the beam side.
Specifically, in the first embodiment, a beam construction method in which a preceding concrete body is provided at the beam bottom portion of the beam end and a beam construction method (FIG. To FIG. 8), and the second embodiment is a beam structure and a beam construction method (FIGS. 9 to 13) for simultaneously constructing a preceding concrete body at the beam bottom portion when placing concrete in a column portion. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
FIG. 1 is a longitudinal sectional view of a column-to-beam joint structure 1 to which a beam structure according to a first embodiment of the present invention is applied. FIG. 2 is a cross-sectional view taken along the line AA of FIG.
A column-to-beam joint structure 1 includes a reinforced concrete column 2 and a reinforced concrete beam 4 joined to a column-beam joint 3 of the column 2. The column 2 is made of concrete having a higher strength than the beam 4. Therefore, when building columns and beams with concrete of different strength, it is necessary to clarify the joint surface between the columns and beams for strength classification and construction management, and the beam structure and beam construction method of the present invention are effective. It becomes.

Column main bars 10 and band bars 11 are arranged in the column 2.
The beam 4 is provided with a lower main bar 20, an upper main bar 21, and a stirrup 22 as a shear reinforcement bar as beam reinforcing bars.
The beam 4 includes a preceding concrete body 30 formed by casting concrete extending in the beam width direction at the beam bottom portion of the beam end portion, and a concrete placed using the joining concrete surface 31 on the preceding concrete body 30. And a post-cast concrete body 32 formed in the above manner.
The joint surface 31 is set at a position closer to the beam center by a predetermined dimension d from the side surface of the column 2, and the preceding concrete body 30 is formed on the beam center side of the joint surface 31.

  The preceding concrete body 30 is made of concrete having the same strength as that of the pillar 2, and the lower main bar 20 of the beam is driven into the preceding concrete body 30. The height dimension of the preceding concrete body 30 is h, and the width dimension is w.

Hereinafter, the construction method of the joint structure 1 of a column and a beam will be described with reference to the flowchart of FIG.
In step S <b> 1, as shown in FIGS. 1 and 2, the preceding concrete body 30 is constructed at the beam bottom portion of the beam end of the beam 4, and the joint surface 31 is formed on the preceding concrete body 30.
In step S2, as shown in FIGS. 1 and 2, concrete is placed on the side of the column 2 and the beam-to-column joint 3 of the joining surface 31 to construct the column 2 and the beam-to-column connection 3.
In step S3, as shown in FIGS. 1 and 2, concrete is cast on the beam 4 side of the joint surface 31 to construct a post-cast concrete body 32. At this time, after removing a joining form 56 described later, concrete is placed on the beam 4 side of the joining surface 31 (see FIG. 8).

Hereinafter, the detailed procedure of step S1 is demonstrated, referring the flowchart of FIG.
As an initial state, it is assumed that the column main reinforcement 10 and the band reinforcement 11 are arranged, and a column form frame (not shown) is installed.
In step S11, as shown in FIGS. 5 and 6, the beam bottom mold 40 is built, and the lower main bar 20, the upper main bar 21, and the ribs are formed on the beam bottom mold 40 as beam reinforcing bars. The muscle 22 is arranged.

  In step S12, as shown in FIG. 5 and FIG. 6, a lath wire net is attached to the inner region of the stirrup 22A located on the joint surface 31 to form a buried mold 50. Further, a dowel bar 51 is attached to the cover portion on the beam side of the joint surface 31. At this time, the height position of the upper end of the dowel bar 51 is set higher than the height dimension h.

  In step S13, as shown in FIG. 5 and FIG. 6, a cover mold 52 that covers the beam bottom and the beam-side cover part is built in the joint surface 31. Further, a cover mold 53 that covers the beam bottom and the beam-side cover portion is installed at a position closer to the center of the beam than the joint surface 31 by the dimension w. Furthermore, an end face formwork 54 is built between the cover formwork 52 and the cover formwork 53 at a position that becomes the beam side face.

  In step S14, as shown in FIGS. 5 and 6, a lath metal mesh is attached to the height dimension h immediately above the cover mold 53 on the beam center side to form a buried mold 55. The filling mold 55 is flush with the cover mold 53.

  In step S15, as shown in FIG. 7, concrete having the same strength as the concrete used for the pillar 2 is placed in the space surrounded by the filling molds 50 and 55, the cover molds 52 and 53, and the end face mold 54. The above-mentioned preceding concrete body 30 is constructed by placing.

  In step S16, after the concrete of the preceding concrete body 30 is hardened, as shown in FIG. 8, the cover molds 52 and 53 and the end face mold 54 are removed, and the beam side mold 41 and the slab covering the beam side surface are removed. A slab mold 42 covering the lower surface and a column beam joint mold 43 surrounding the column beam joint 3 are installed.

  In step S <b> 17, as shown in FIG. 8, a long member such as a square pipe is attached to the dowel bar 51 that has been driven into the preceding concrete body 30, so that a joint form 56 is obtained. As a result, the buried mold 50 is attached to the inner side of the loose streaks 22A on the preceding concrete body 30, and the splicing form 56 is placed on the outer side of the streaks 22A on the preceding concrete body 30, that is, the cover portion of the streaks 22A. Is attached, and the joint surface 31 is constituted by the filling mold 50 and the joint mold 56.

According to this embodiment, there are the following effects.
(1) A preceding concrete body 30 is provided at the beam bottom portion at the end of the beam, and then a joining surface 31 is provided on the preceding concrete body 30, and the concrete is placed on the joint side of the joining surface 31 to the column beam joint. Set up. After that, concrete is placed on the beam 4 side of the joint surface 31, the post-cast concrete body 32 is provided, and the beam 4 is formed. Therefore, when the concrete of the pillar 2 is placed, it is possible to prevent the concrete nose from flowing out to the beam 4 side. Moreover, since the formwork at the bottom of the beam is not processed, the cost is reduced. Moreover, concrete can be easily handed over with the preceding concrete body 30 and the vertical joint surface 31 thereon.

  (2) After removing the rod-shaped joint form 56 from the cover portion of the stirrup 22A, concrete is placed on the beam 4 side of the joint surface 31 to form the post-cast concrete body 32. Therefore, a predetermined cover thickness can be secured for the lower main bar 20 and the rib 22 of the beam 4 without driving a metal that may corrode into the joint surface 31 between the cover part of the beam 4 and the column 2. In addition, since no metal buried mold is placed in the cover thickness portion of the beam, the soundness of the concrete of the beam 4 can be ensured.

  (3) Since a lath metal mesh was provided as the filling form 50, a diamond-shaped uneven surface was formed on the joint surface of the concrete on both sides of the lath metal mesh. The integrity of the concrete on both sides can be increased.

[Second Embodiment]
FIG. 9 is a longitudinal sectional view of a column-to-beam joint structure 1A to which the beam structure according to the second embodiment of the present invention is applied.
In the present embodiment, the position of the preceding concrete body 30A and the method for constructing the joint structure 1A of columns and beams are different from those in the first embodiment.

  That is, the preceding concrete body 30 </ b> A is formed on the side of the joint surface 31 on the column beam joint 3 side. The height of the preceding concrete body 30 is h1, and the lower main bar 20 of the beam is placed on the preceding concrete body 30.

Hereinafter, a construction method of the column-to-beam joint structure 1A will be described with reference to the flowchart of FIG.
In step S <b> 21, as shown in FIG. 9, the pillar 2 and the preceding concrete body 30 </ b> A are constructed integrally, and the joining surface 31 is formed on the preceding concrete body 30.
In step S <b> 22, as shown in FIG. 9, concrete is placed on the joint surface 31 on the column beam joint 3 side.
In step S23, as shown in FIG. 9, concrete is placed on the beam 4 side of the joint surface 31 to construct a post-cast concrete body 32. At this time, after removing the joint form 56, concrete is placed on the beam 4 side of the joint surface 31.

Hereinafter, the detailed procedure of step S21 is demonstrated, referring the flowchart of FIG.
As an initial state, it is assumed that the column main reinforcement 10 and the band reinforcement 11 are arranged, and a column form frame (not shown) is installed.
In step S31, as shown in FIG. 12, the beam-to-beam joint mold 43 and the beam bottom mold 40 are built, and the cover mold 57 having the height dimension h1 is built in the position of the joining surface 31. Further, a dowel bar 51 is attached to the cover portion on the beam side of the joint surface 31. At this time, the height position of the upper end of the dowel bar 51 is set higher than the height dimension h <b> 1 of the cover mold 57.

In step S32, as shown in FIG. 12, when placing the concrete of the column 2, the concrete is driven to the height of the upper end of the cover mold 57 in the column beam joint mold 43 and the cover mold 57. The pillar 2 and the above-described preceding concrete body 30A are constructed integrally.
In step S <b> 33, as shown in FIG. 13, the cover mold 57 is removed, and the lower main bar 20, the upper main bar 21, and the stirrup bar 22 are arranged on the beam bottom mold 40. At this time, the lower main reinforcement 20 is placed on the preceding concrete body 30A.

  In step S34, as shown in FIG. 13, a lath metal mesh is attached to the inner region of the stirrup 22A located on the joining surface 31 to make the mold 50.

  In step S35, as shown in FIG. 13, a beam side mold 41 covering the beam side surface and a slab mold 42 covering the lower surface of the slab are built.

  In step S36, as shown in FIG. 13, a long member such as a square pipe is attached to the dowel bar 51 driven into the preceding concrete body 30 to form a splicing form frame 56 located outside the ribbed bar 22A. . As a result, the buried mold 50 is attached to the inner side of the loose streaks 22A on the preceding concrete body 30, and the splicing form 56 is placed on the outer side of the streaks 22A on the preceding concrete body 30, that is, the cover portion of the streaks 22A. Is attached, and the joint surface 31 is constituted by the filling mold 50 and the joint mold 56.

According to this embodiment, in addition to the above (1) to (3), there are the following effects.
(4) When the concrete of the pillar 2 is placed, the concrete of the preceding concrete body 30A for preventing the outflow of the column concrete is also placed, so that only the preceding concrete body 30 is constructed as in the first embodiment. There is no need to cast concrete. Therefore, according to 2nd Embodiment, compared with 1st Embodiment, the frequency | count of placement of concrete can be reduced and work efficiency can be improved.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
For example, in the first embodiment described above, the preceding concrete body 30 is formed of concrete having the same strength as the pillar 2, but the present invention is not limited thereto, and the preceding concrete body 30 is formed of concrete having the same strength as the beam 4. May be.

  In each of the above-described embodiments, the concrete on the side of the column 2 and the beam-to-column joint 3 is placed, and then the concrete on the side of the beam 4 is placed so that the concrete on the side of the column 2 and the beam-to-column joint 3 is on the beam 4 side. Although the preceding concrete body 30 was provided in order to prevent it from flowing out, it is not limited to this. That is, after the concrete on the beam 4 side is placed, the concrete on the column 2 and the column beam joint 3 side is placed, and the concrete on the beam 4 side flows out to the column 2 and the column beam joint 3 side. In order to prevent this, a preceding concrete body may be provided.

DESCRIPTION OF SYMBOLS 1, 1A ... Joint structure of column and beam 2 ... Column 3 ... Column beam joint 4 ... Beam 10 ... Column main reinforcement 11 ... Band reinforcement 20 ... Lower main reinforcement 21 ... Upper main reinforcement 22, 22A ... Stirrup reinforcement (shear reinforcement) )
30, 30A ... Preceding concrete body 31 ... Joint surface 32 ... Post-cast concrete body 40 ... Beam bottom formwork 41 ... Beam-side formwork 42 ... Slab formwork 43 ... Column beam joint formwork 50 ... Filling formwork 51 ... Dowels 52, 53 ... Cover formwork 54 ... End face formwork 55 ... Filling formwork 56 ... Joint formwork 57 ... Cover formwork

Claims (3)

A concrete beam structure joined to a concrete pillar,
A preceding concrete body formed extending in the beam width direction at the beam bottom portion of the beam end; and
A post-cast concrete body formed by placing concrete as a joint surface on the preceding concrete body, and
The lower main bar of the beam is driven into the preceding concrete body or placed on the preceding concrete body. A method of constructing a concrete beam to be joined to a concrete pillar,
Arranging the main and shear reinforcements of the beam;
Concrete is cast on the beam bottom portion of the beam end of the beam to form a preceding concrete body, and a filling form is attached to the inside of the shear reinforcement on the preceding concrete body, and Attaching a rod-shaped joint form extending vertically to the outside of the shear reinforcement on the preceding concrete body;
Forming a post-cast concrete body by placing concrete on the beam side of the joint surface with the surface constituted by the filling mold form and the joint mold form as a joint surface; A method for constructing a beam, comprising: Before the step of forming the post-cast concrete body, further comprising the step of placing concrete on the column side of the joint surface, using the buried mold and the joint mold as the joint surface,
In the step of forming the post-cast concrete body, the rod-shaped joint form is removed, and then concrete is placed on the beam side of the joint surface to form the post-cast concrete body. The method for constructing a beam according to claim 2.

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