JP6851686B2 - How to build a beam - Google Patents

Description

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

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

Patent Document 1 provides a rectangular opening in which a beam floor at a position separated by a predetermined dimension from the column side is cut out when concrete having different properties is cast and joined between the column, the beam and the slab. A beam floor stopper is provided so that the excised rectangular beam floor cut piece is erected toward the column side. Further, a slag-stopping structure for concrete joints is shown in which concrete stoppers such as an air fence, formwork lath, and metal plate are arranged in the concrete joint portion.

Patent Document 2 discloses a concrete weiring device to be installed in a formwork for joining concrete. This concrete weir blocking device includes a damping plate composed of a plurality of plate members and a guide member having a slit formed in the beam formwork for setting the damming plate from the side surface. ..

In Patent Document 3, when joining or adding high-fluidity concrete in a vertical plane, a retaining formwork having a mesh is fixed to the joint or the added portion, and a steel plate is attached to the back surface thereof while avoiding the beam main bar. After hitting, the method of stopping the high-fluidity concrete into which the high-fluidity concrete is driven is shown.

However, in the slag-stopping structure of Patent Document 1, there is a problem that it takes a lot of time and effort to construct the formwork at the bottom of the beam because an opening is provided for processing.
Further, in the concrete weir blocking device of Patent Document 2, there is a problem that concrete leaks from the joint surface because a gap is generated between a plurality of plate members inserted through the slit.
Further, the method of stopping the high-fluidity concrete of Patent Document 3 has a problem that a gap is generated at the cover portion of the beam reinforcing bar at the bottom of the beam. In order to eliminate this gap, it is necessary to process the steel plate with high accuracy for each joint, which is costly.

Japanese Patent No. 5893792 Japanese Unexamined Patent Publication No. 2004-137693 Japanese Unexamined Patent Publication No. 2000-27439

The present invention can prevent the concrete slag (cement paste) from flowing over the beam bottom formwork and flowing out to the beam side when the concrete of the column is placed, and the vertical joint surface can be prevented at low cost. The purpose is to provide a method for constructing beams that can be easily joined with concrete.

As a beam structure to be joined to a column, the present inventors provide a leading concrete body in which a part of the lower main bar of the beam is embedded in the beam bottom portion at the beam end, and a dam is provided on the upper surface of the leading concrete body. By installing a stop mold (for example, a buried mold or a joint mold) and placing concrete in advance on the beam-beam joint side with the dam-stop mold as the boundary, the beam is hit on the beam joint side. Focusing on the fact that the installed concrete slag can be easily and inexpensively prevented from flowing out to the beam side, the beam structure and the beam construction method of the present invention have been invented.

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 is a beam bottom portion of a beam end portion. In addition, concrete is formed by extending the leading concrete body in the beam width direction (for example, the leading concrete bodies 30 and 30A described later) and the leading concrete body as a joint surface (for example, the joint surface 31 described later). The lower main bar of the beam (for example, the lower main bar 20 described later) includes the post-cast concrete body (for example, the post-cast concrete body 32 described later) formed by casting the above-mentioned leading concrete body. It is characterized in that it is driven into or placed on the preceding concrete body.

According to the present invention, first, a leading concrete body is provided at the beam bottom portion of the beam end portion, and then concrete (described later, S2 in FIG. 3) is placed on the column-beam joint portion side on the leading concrete body. To do. After that, concrete is cast on the beam side above the leading concrete body to provide a post-casting concrete body to form the beam. Therefore, it is possible to prevent the concrete slag from flowing out to the beam side when the concrete of the pillar is placed. In addition, since the formwork at the bottom of the beam is not processed, the cost is low. Further, it is possible to realize a beam structure formed by a leading concrete body and a post-casting concrete body easily joined by a vertical joint surface on the leading concrete body.

The method for constructing a beam of the second invention is a method for constructing a concrete beam to be joined to a concrete column, and the main bar of the beam (for example, the lower main bar 20 and the upper main bar 21 described later) and shearing. A step of arranging reinforcing bars (for example, stirrups 22 and 22A described later) (for example, step S11 described later) and a concrete body (for example, step S11 described later) are cast with concrete at the bottom of the beam to form a preceding concrete body ( For example, the preceding concrete body 30) described later is formed, and a mold for filling (for example, filling filling described later) is formed inside the shear reinforcing bar (for example, the stirrups 22A described later) on the preceding concrete body. A step of attaching the mold 50) and attaching a rod-shaped joint mold (for example, a joint mold 56 described later) extending in the vertical direction to the outside of the shear reinforcing bar on the preceding concrete body (for example). Steps S12 to S17, which will be described later, and the surface composed of the filling mold and the jointing mold will be used as a joint surface (for example, the joint surface 31 described later), and the beam side of the joint surface. It is characterized by comprising a step (for example, step S3 described later) of casting concrete into the concrete to form a post-cast concrete body (for example, a post-cast concrete body 32 described later).
Here, the beam side of the joint surface is the beam center side of the joint surface.

According to the present invention, first, a leading concrete body is provided at the beam bottom portion of the beam end portion. Next, the buried formwork and the jointed formwork are mounted on the preceding concrete body, and the surface composed of the buried formwork and the jointed formwork is used as the jointed surface on the beam-column joint side. Place concrete in the formwork. After that, concrete is cast on the beam side (beam center side) of the joint surface, a post-cast concrete body is provided, and the beam is formed. Therefore, it is possible to prevent the concrete slag from flowing out to the beam side when the concrete of the pillar is placed. Further, by installing the preceding concrete body, it is possible to prevent the concrete slag cast on the column from flowing out to the beam side easily and at low cost without processing the formwork at the bottom of the beam. In addition, concrete can be easily joined at the preceding concrete body and the vertical joint surface above it.

In the method of constructing a beam of the third invention, before the step of forming the post-cast concrete body, the buried formwork and the joint formwork are used as joint surfaces, and the pillar side of the joint surface is used. In the step of forming the post-casting concrete body, the step of placing concrete in the concrete (for example, step S2 described later) is further provided, the rod-shaped joint formwork is removed, and then the beam of the joint surface is formed. It is characterized in that concrete is cast on the side to form a post-casting concrete body.

According to the present invention, after removing the joint formwork from the outside of the shear reinforcing bar, that is, the covering portion of the shear reinforcing bar, concrete is cast on the beam side of the joint surface to form a post-cast concrete body. Therefore, it is possible to secure a predetermined cover thickness for the beam main bar and the shear reinforcing bar without driving metal that may corrode into the joint surface between the beam cover portion and the column. In addition, since the metal buried formwork is not left in the cover thickness portion of the beam, the soundness of the concrete of the beam can be ensured.

According to the present invention, by providing the leading concrete body at the beam bottom portion of the beam end, it is possible to easily and at low cost prevent the concrete slag cast on the column from flowing out to the beam side, and the leading concrete body and the leading concrete body thereof. It is possible to realize a method of constructing a beam formed of a post-cast concrete body jointed at the upper vertical joint surface.

It is a vertical sectional view of the joint structure of a column and a beam which concerns on 1st Embodiment of this invention. FIG. 1 is a cross-sectional view taken along the line AA of FIG. It is a schematic flowchart of the construction method of a joint structure (first embodiment). It is a detailed flowchart of a method of constructing a joint structure (first embodiment). It is a top view and BB sectional view explaining the construction method of the joint structure. 5 is a cross-sectional view taken along the line CC and a cross-sectional view taken along the line DD of FIG. It is a top view and EE sectional view explaining the construction method of the joint structure. It is a top view and FF sectional view explaining the construction method of the joint structure. It is a vertical sectional view of the joint structure of a column and a beam which concerns on 2nd Embodiment of this invention. It is a schematic flowchart of the construction method of a joint structure (second embodiment). It is a detailed flowchart of a method of constructing a joint structure (second embodiment). It is a top view and GG sectional view explaining the construction method of the joint structure. It is a top view and HH sectional view explaining the construction method of the joint structure.

In the present invention, as a beam structure to be joined to a column, a leading concrete body is provided at the bottom of the beam at the beam end, a buried mold is provided on the upper surface of the leading concrete body, and the cover thickness on both side surfaces of the beam main bar is provided. This is a beam structure and a beam construction method in which a joint mold is provided in a portion to prevent the concrete slag cast on the column from flowing out to the beam side.
Specifically, the first embodiment is a beam structure in which a preceding concrete body is provided at the beam bottom portion of the beam end and a beam construction method (FIG. 1) before concrete is placed on the beam-column joint side. ~ FIG. 8), and the second embodiment is a beam structure and a beam construction method (FIGS. 9 to 13) in which a preceding concrete body of a beam bottom portion is simultaneously constructed when concrete is placed on a column portion. ..

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the following embodiments, the same components will be designated by the same reference numerals, and the description thereof will be omitted or simplified.
[First Embodiment]
FIG. 1 is a vertical cross-sectional view of a joint structure 1 of a column and a beam to which the beam structure according to the first embodiment of the present invention is applied. FIG. 2 is a cross-sectional view taken along the line AA of FIG.
The column-beam joint structure 1 includes a reinforced concrete column 2 and a reinforced concrete beam 4 joined to the column-beam joint 3 of the column 2. The pillar 2 is made of concrete having a higher strength than the beam 4. Therefore, when constructing columns and beams with concrete of different strengths, it is necessary to clarify the joint surface between columns and beams in terms of 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 on the columns 2.
The beam 4 is provided with a lower main bar 20, an upper main bar 21, and a loose bar 22 as a shear reinforcing bar as beam reinforcing bars.
The beam 4 has a leading concrete body 30 formed by placing concrete extending in the beam width direction on the beam bottom portion at the beam end, and concrete is placed on the leading concrete body 30 as a joint surface 31. A post-casting concrete body 32 formed of the above-mentioned material is provided.
The joint surface 31 is set at a position closer to the center of the beam by a predetermined dimension d from the side surface of the column 2, and the leading concrete body 30 is formed on the beam center side of the joint surface 31.

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

Hereinafter, a method of constructing the joint structure 1 of the column and the beam will be described with reference to the flowchart of FIG.
In step S1, as shown in FIGS. 1 and 2, a leading concrete body 30 is constructed at the beam bottom portion of the beam end portion of the beam 4, and a joint surface 31 is formed on the leading concrete body 30.
In step S2, as shown in FIGS. 1 and 2, concrete is cast on the side of the column 2 and the beam-column joint 3 of the joint surface 31 to construct the column 2 and the beam-column joint 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 the post-cast concrete body 32. At this time, after removing the joint formwork 56 described later, concrete is placed on the beam 4 side of the joint surface 31 (see FIG. 8).

Hereinafter, the detailed procedure of step S1 will be described with reference to the flowchart of FIG.
As an initial state, it is assumed that the column main bars 10 and the band bars 11 are arranged and a column formwork (not shown) is built.
In step S11, as shown in FIGS. 5 and 6, the beam bottom formwork 40 is built, and the lower main bar 20, the upper main bar 21, and the stirrups are built on the beam bottom formwork 40 as beam reinforcing bars. Reinforce the muscle 22.

In step S12, as shown in FIGS. 5 and 6, a lath wire mesh is attached to the inner region of the stirrups 22A located on the joint surface 31 to form a buried formwork 50. Further, the 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 FIGS. 5 and 6, a cover form 52 that covers the beam bottom and the cover portion on the beam side is built in the joint surface 31. Further, a cover form 53 that covers the beam bottom and the cover portion on the beam side is built at a position on the beam center side by the dimension w from the joint surface 31. Further, the end face form 54 is built between the cover form 52 and the cover form 53 at the position on the side surface of the beam.

In step S14, as shown in FIGS. 5 and 6, a lath wire mesh is attached to the height dimension h directly above the cover form 53 on the center side of the beam to form a buried form 55. The buried formwork 55 is flush with the cover formwork 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 formwork 50, 55, the cover formwork 52, 53, and the end face formwork 54. Casting is performed to construct the above-mentioned leading concrete body 30.

In step S16, after the concrete of the preceding concrete body 30 is hardened, as shown in FIG. 8, the cover formwork 52, 53 and the end face formwork 54 are demolded, and the beam side formwork 41 and the slab covering the beam side surface are removed. A slab formwork 42 that covers the lower surface and a beam-column joint formwork 43 that surrounds the beam-column joint 3 are built.

In step S17, as shown in FIG. 8, 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 joint form 56. As a result, the filling formwork 50 is attached to the inside of the loose bar 22A on the leading concrete body 30, and the joint formwork 56 is attached to the outside of the loose bar 22A, that is, the cover portion of the loose bar 22A on the leading concrete body 30. Is attached, and the joint surface 31 is composed of the buried form 50 and the joint form 56.

According to this embodiment, there are the following effects.
(1) A leading concrete body 30 is provided at the beam bottom portion of the beam end portion, and then a joint surface 31 is provided on the leading concrete body 30, and concrete is cast on the column-beam joint side of the joint surface 31. Set up. After that, concrete is cast on the beam 4 side of the joint surface 31 to provide a post-cast concrete body 32 to form the beam 4. Therefore, when the concrete of the pillar 2 is cast, it is possible to prevent the concrete slag from flowing out to the beam 4 side. In addition, since the formwork at the bottom of the beam is not processed, the cost is low. In addition, concrete can be easily joined by the leading concrete body 30 and the vertical joint surface 31 above the preceding concrete body 30.

(2) After removing the rod-shaped joint formwork 56 from the cover portion of the stirrups 22A, concrete is cast on the beam 4 side of the joint surface 31 to form the post-cast concrete body 32. Therefore, it is possible to secure a predetermined cover thickness for the lower main bar 20 and the stirrups 22 of the beam 4 without driving metal that may corrode into the joint surface 31 between the cover portion of the beam 4 and the column 2. Further, since the metal buried formwork is not left in the cover thickness portion of the beam, the soundness of the concrete of the beam 4 can be ensured.

(3) Since a lath wire mesh was provided as the filling form 50, a diamond-shaped uneven surface was formed on the concrete joint surface on both sides of the lath wire mesh, so that the lath wire mesh was sandwiched and joined. It is possible to enhance the integrity of the concrete on both sides.

[Second Embodiment]
FIG. 9 is a vertical cross-sectional view of a column-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 of constructing the joint structure 1A between the column and the beam are different from those in the first embodiment.

That is, the leading concrete body 30A is formed on the beam-column joint 3 side of the joint surface 31. Further, the height dimension of the leading concrete body 30 is h1, and the lower main bar 20 of the beam is placed on the leading concrete body 30.

Hereinafter, a method of constructing the joint structure 1A between the column and the beam will be described with reference to the flowchart of FIG.
In step S21, as shown in FIG. 9, the column 2 and the leading concrete body 30A are integrally constructed, and the joint surface 31 is formed on the leading concrete body 30.
In step S22, as shown in FIG. 9, concrete is placed on the beam-column joint 3 side of the joint surface 31.
In step S23, as shown in FIG. 9, concrete is cast on the beam 4 side of the joint surface 31 to construct the post-cast concrete body 32. At this time, after removing the joint formwork 56, concrete is poured on the beam 4 side of the joint surface 31.

Hereinafter, the detailed procedure of step S21 will be described with reference to the flowchart of FIG.
As an initial state, it is assumed that the column main bars 10 and the band bars 11 are arranged and a column formwork (not shown) is built.
In step S31, as shown in FIG. 12, the column-beam joint formwork 43 and the beam bottom formwork 40 are built, and the cover formwork 57 having a height dimension h1 is built at the position of the joint surface 31. Further, the 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 h1 of the cover form 57.

In step S32, as shown in FIG. 12, when the concrete of the column 2 is placed, the concrete is driven into the column-beam joint formwork 43 and the cover formwork 57 to the height of the upper end of the cover formwork 57. The pillar 2 and the above-mentioned leading concrete body 30A are integrally constructed.
In step S33, as shown in FIG. 13, the cover formwork 57 is demolded, and the lower main bar 20, the upper main bar 21, and the stirrups 22 are arranged on the beam bottom formwork 40. At this time, the lower main bar 20 is placed on the leading concrete body 30A.

In step S34, as shown in FIG. 13, a lath wire mesh is attached to the inner region of the stirrups 22A located on the joint surface 31 to form a buried formwork 50.

In step S35, as shown in FIG. 13, the beam side formwork 41 covering the side surface of the beam and the slab formwork 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 joint formwork 56 located outside the stirrups 22A. .. As a result, the filling formwork 50 is attached to the inside of the loose bar 22A on the leading concrete body 30, and the joint formwork 56 is attached to the outside of the loose bar 22A, that is, the cover portion of the loose bar 22A on the leading concrete body 30. Is attached, and the joint surface 31 is composed of the buried form 50 and the joint form 56.

According to this embodiment, in addition to the above-mentioned (1) to (3), the following effects are obtained.
(4) When the concrete of the pillar 2 is poured, the concrete of the preceding concrete body 30A for preventing the outflow of the pillar concrete is also poured, so that only for constructing the preceding concrete body 30 as in the first embodiment. There is no need to cast concrete. Therefore, according to the second embodiment, the number of times of placing concrete can be reduced and the work efficiency can be improved as compared with the first embodiment.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
For example, in the above-described first embodiment, the leading concrete body 30 is formed of concrete having the same strength as the column 2, but the preceding concrete body 30 is formed of concrete having the same strength as the beam 4. You may.

In each of the above-described embodiments, after the concrete on the side of the column 2 and the beam-column joint 3 is placed, the concrete on the beam 4 side is placed, and the concrete on the side of the column 2 and the beam-column joint 3 is placed on the beam 4 side. The leading concrete body 30 is provided in order to prevent the concrete from flowing out to the concrete body 30, but the present invention is not limited to this. That is, after the concrete on the beam 4 side is cast, the concrete on the column 2 and the beam-column joint 3 side is cast, and the concrete on the beam 4 side flows out to the column 2 and the beam-column joint 3 side. A leading concrete body may be provided to prevent this.

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

Claims (2)

A method of constructing concrete beams that are joined to concrete columns.
The process of arranging the main reinforcement and shear reinforcement of the beam, and
Concrete is cast on the bottom of the beam at the beam end of the beam to form a leading concrete body, and a filling form is attached to the inside of the shear reinforcing bar on the leading concrete body. , A step of attaching a rod-shaped joint formwork extending in the vertical direction to the outside of the shear reinforcing bar on the preceding concrete body,
A step of forming a post-cast concrete body by placing concrete on the beam side of the joint surface, using the surface composed of the buried form and the joint form as a joint surface. A method of constructing a beam, which is characterized by being provided. Prior to the step of forming the post-cast concrete body, a step of placing concrete on the pillar side of the joint surface with the buried formwork and the joint form as a joint surface is further provided.
The step of forming the post-cast concrete body is characterized in that the rod-shaped joint formwork is removed, and then concrete is cast on the beam side of the joint surface to form the post-cast concrete body. The method for constructing a beam according to claim 1.

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