JP2015101821A - Concrete placing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete placing method that can prevent segregation of concrete aggregate when constructing a steel pipe concrete column.SOLUTION: The following concrete placing method is used to place concrete into a steel pile 41. This concrete placing method includes the following steps: a step S1 for constructing a steel pile 41 after preparing a hopper 10 for storing concrete and a concrete placing tool 1 that is provided with a cylindrical, flexible concrete supply pipe 20, whose inner faces are so coherent that the inner faces come into a close contact with each other, extending from the hopper 10; a step S3 for setting the hopper 10 just above the steel pile 41, setting the concrete supply pipe 20 into the steel pile 41 and arranging the concrete supply pipe 20 in a way that it runs along the central axis of the steel pile 41; and step S4 for dropping down concrete in the hopper 10 through the concrete supply pipe 20 into the steel pile 41.

Description

  The present invention relates to a concrete placing method. Specifically, the present invention relates to a concrete placing method for placing concrete in a steel pipe when constructing a steel pipe concrete column.

Conventionally, when a filled steel pipe concrete column is constructed, it is necessary to cast concrete into the steel pipe. In this case, in order to prevent the concrete aggregate from separating, it has been proposed to use a concrete placing jig (see Patent Document 1).
Specifically, the concrete placing jig includes a hopper in which concrete is accommodated, and a cylindrical concrete loading tube extending from the hopper. The hopper is disposed immediately above the steel pipe. The concrete loading pipe is made of steel and extends from the top of the steel pipe to the vicinity of the bottom.

  According to this concrete placing jig, the concrete in the hopper is dropped into the steel pipe through the inside from the concrete loading pipe. At this time, the concrete is always ejected from the tip of the concrete loading pipe, so that the impact at the time of dropping of the concrete is alleviated and separation of the concrete aggregate is prevented.

  In particular, when constructing a filled steel pipe concrete column using this concrete placing jig, steel pipe columns corresponding to two or three layers of the building are manufactured in advance at the steel frame manufacturing factory, and this steel pipe column is then constructed at the construction site. After carrying in and building, concrete is filled using this concrete placing jig. Therefore, since the fall height of the concrete is from the hopper to the lower end surface inside the steel pipe column, there is a high possibility that the aggregate is separated.

Japanese Patent Laid-Open No. 5-272240

  However, in reality, there is a changeover of a ready-mixed concrete car and a refilling work of vibrators, so it is difficult to always eject concrete from the tip of the concrete loading pipe, and it is difficult to prevent separation of the concrete aggregate. was difficult.

  An object of this invention is to provide the concrete placement method which can prevent isolation | separation of the aggregate of concrete, when constructing a steel pipe concrete pillar.

  The concrete placement method according to claim 1 is a concrete placement method for a column (for example, a steel pipe concrete column 40 described later), a hopper (for example, a hopper 10 described later) in which concrete is accommodated, and the hopper. And a concrete supply pipe (for example, concrete supply pipe 20 described later) having a cylindrical shape in which at least some of the inner surfaces are in close contact with each other and having flexibility. A placing jig 1) is prepared, and a step (for example, step S1 to be described later) in which the pillar formwork (for example, a steel pipe 41 described later) is built, and the hopper is disposed immediately above the formwork. And a step of arranging the concrete supply pipe along the column axis in the mold (for example, step S3 described later), and the concrete in the hopper, Step On drop in said steel tube through the interior of the Nkurito supply pipe (e.g., step S4 described later), characterized in that it comprises a a.

  Here, the concrete column includes a steel pipe concrete column (for example, a later-described steel pipe concrete column) including a steel pipe (for example, a later-described steel tube 41) and concrete (for example, a later-described concrete 42) filled in the steel pipe. 40), and the mold is preferably the steel pipe.

  According to the present invention, since the concrete supply pipe is formed of a flexible material and has a cylindrical shape in which at least some of the inner surfaces are in close contact with each other, when the concrete is supplied from the hopper to the concrete supply pipe, the concrete supply pipe Of these, only the portion pressed by the concrete body swells, and the lower and upper portions of the concrete supply pipe are still in contact with each other, that is, in a crushed state. Therefore, since the concrete body falls while being wrapped in the concrete supply pipe, the impact applied to the concrete body can be reliably mitigated, and the concrete can be placed while preventing the separation of the aggregate of the concrete body. In particular, when concrete is cast on a steel pipe concrete column, the drop height of the concrete increases, so that there is a remarkable effect.

  In the concrete placing method according to claim 2, a cap (for example, a cap 30 described later) is attached to a tip of the concrete supply pipe, and a plurality of openings (for example, an opening described later) is attached to the cap. 31) is formed.

According to the present invention, the cap is attached to the tip of the concrete supply pipe, and a plurality of openings are formed in the cap. Therefore, the falling concrete body is received by the cap and is then discharged from the opening. The impact on the concrete body can be further reduced.
In addition, when placing concrete, the cap attached to the tip of the concrete supply pipe is buried in the concrete that has already been poured in, and the concrete is dropped through the inside of the concrete supply pipe to prevent air from entering the concrete. Can be prevented.

  The concrete placement method according to claim 3 is characterized in that the cap and the hopper are connected by a wire (for example, a wire 34 described later).

  According to this invention, since the cap and the hopper are connected by the wire, it is possible to prevent the cap from dropping from the tip of the concrete supply pipe.

  According to the present invention, the concrete supply pipe is made of a flexible material and has a cylindrical shape whose inner surfaces are in close contact with each other. Therefore, when concrete is supplied from the hopper to the concrete supply pipe, the concrete supply pipe is pressed against the concrete body. Only the portion that has been swelled is expanded, and the lower and upper portions of the concrete supply pipe are still in contact with each other, that is, in a crushed state. Therefore, since the concrete body falls while being wrapped in the concrete supply pipe, the impact applied to the concrete body can be reliably mitigated, and the concrete can be placed while preventing the separation of the aggregate of the concrete body.

It is a side view of the concrete placement jig used for the concrete placement method concerning one embodiment of the present invention. It is a cap perspective view of the concrete placement jig concerning the embodiment. It is a flowchart of the procedure which places concrete by the concrete placement method which concerns on the said embodiment. It is a sectional side view (the 1) for demonstrating the procedure which places concrete by the concrete placement method which concerns on the said embodiment. It is a sectional side view (the 2) for demonstrating the procedure which places concrete by the concrete placement method which concerns on the said embodiment. It is a sectional side view which shows the state in which concrete falls by the concrete placement method which concerns on the said embodiment. It is a sectional side view (the 3) for demonstrating the procedure which places concrete by the concrete placement method which concerns on the said embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a concrete placing jig 1 used in a concrete placing method according to an embodiment of the present invention.
The concrete placing jig 1 includes a hopper 10 in which concrete is accommodated, a cylindrical concrete supply pipe 20 extending from the hopper 10, and a cap 30 attached to the tip of the concrete supply pipe 20.

  The hopper 10 has a box shape with an upper surface opened. The hopper 10 has a funnel shape in which the inner diameter becomes thinner as it goes downward, and a discharge port 11 that can be opened and closed by remote control operation is provided at the lower end of the hopper 10.

  The concrete supply pipe 20 is connected to the discharge port 11 of the hopper 10. The concrete supply pipe 20 is made of polyvinyl chloride, has flexibility, and has a cylindrical shape in which inner surfaces are in close contact with each other. The concrete supply pipe 20 is provided with marks 21 at predetermined intervals, for example, every 50 cm from the tip.

FIG. 2 is a perspective view of the cap 30.
The cap 30 has a shape that becomes thinner toward the tip, and a plurality of openings 31 are formed in the cap 30.
Specifically, the cap 30 includes a cylindrical base portion 32 and a belt-like belt-like member 33 that extends from the tip edge of the base portion 32 and is joined to each other. The opening 31 described above is a gap between the band-shaped members 33.
The base 32 of the cap 30 and the hopper 10 are connected by a wire 34.

Hereinafter, the procedure for placing the concrete of the steel pipe concrete pillar 40 using the concrete placing jig 1 of the present invention will be described with reference to the flowchart of FIG.
The steel pipe concrete pillar 40 is provided with a steel pipe 41 as a mold having a cylindrical shape whose lower surface is closed, and a concrete 42 filled in the steel pipe 41 (see FIG. 7).

  In step S1, the steel pipe 41 of the steel pipe concrete pillar 40 is built on the floor frame 2 as shown in FIG. At this time, the fall prevention wire 51 is stretched between the vicinity of the column head of the steel pipe 41 and the floor frame 2 to prevent the steel pipe 41 from falling. Thereafter, the installation of the steel pipe 41 is adjusted.

  In step S <b> 2, as shown in FIG. 4, a temporary scaffold 50 is installed on the floor frame 2 so as to surround the steel pipe 41. The temporary scaffold 50 is a seven-stage frame scaffold here.

In step S3, the concrete placing jig 1 is set on the steel pipe 41 as shown in FIG.
That is, the concrete is accommodated in the hopper 10 of the concrete placing jig 1, and then the hopper 10 is lifted by the crane 52 and disposed immediately above the steel pipe 41. Further, the concrete supply pipe 20 is put into the steel pipe 41, and the concrete supply pipe 20 is arranged along the central axis of the steel pipe 41, that is, the column axis.

In step S4, concrete is placed in the steel pipe 41.
That is, the discharge port 11 of the hopper 10 is appropriately opened and closed by a remote control operation, and the concrete in the hopper 10 is dropped into the steel pipe 41 through the concrete supply pipe 20.

  When the concrete body 43 is supplied to the concrete supply pipe 20, as shown in FIG. 6, only the portion pressed by the concrete body 43 in the concrete supply pipe 20 swells, and the concrete supply pipe 20 is lower than the concrete body 43. The upper part is still in a state where the inner surfaces are in close contact with each other, that is, in a crushed state. Therefore, the concrete body 43 falls in a state wrapped in the concrete supply pipe 20.

  Thereafter, as shown in FIG. 7, the concrete supply pipe 20 is gradually pulled up in the direction of the arrow in FIG. 7 by the crane 52, and the vicinity of the upper end of the steel pipe 41 is maintained while maintaining the state where the cap 30 is already buried in the poured concrete. Put concrete up to.

  At this time, the height position of the surface of the concrete 42 is measured with the steel tape 53, and the height position of the concrete supply pipe 20 is confirmed by the mark 21 of the concrete supply pipe 20 and attached to the tip of the concrete supply pipe 20. The cap 30 is slightly buried in the concrete 42.

According to this embodiment, there are the following effects.
(1) Since the concrete supply pipe 20 is formed of a flexible material and has a cylindrical shape whose inner surfaces are in close contact with each other, when the concrete 42 is supplied from the hopper 10 to the concrete supply pipe 20, the concrete supply pipe 20 Only the portion pressed by the concrete body 43 swells, and the lower and upper portions of the concrete supply pipe 20 are still in a state where the inner surfaces are in close contact with each other, that is, in a crushed state. Therefore, since the concrete body 43 falls in a state of being wrapped in the concrete supply pipe 20, the impact applied to the concrete body 43 can be surely mitigated, and the concrete 42 can be placed while preventing the separation of the aggregate of the concrete body 43. .

(2) Since the cap 30 is attached to the tip of the concrete supply pipe 20 and the plurality of openings 31 are formed in the cap 30, the falling concrete body 43 is received by the cap 30, and then from the opening 31. Since it is discharged, the impact applied to the concrete body 43 can be further alleviated.
In addition, when placing concrete, the cap 30 attached to the tip of the concrete supply pipe 20 is buried in the already poured concrete, and the concrete is dropped through the concrete supply pipe 20 so that air is mixed into the concrete. Can be prevented.

  (2) Since the base portion 32 of the cap 30 and the hopper 10 are connected by the wire 34, the cap can be prevented from falling off from the tip of the concrete supply pipe.

  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.

DESCRIPTION OF SYMBOLS 1 ... Concrete placement jig 2 ... Floor frame 10 ... Hopper 11 ... Discharge port 20 ... Concrete supply pipe 21 ... Mark 30 ... Cap 31 ... Opening 32 ... Base 33 ... Band-shaped member 34 ... Wire 40 ... Steel pipe concrete pillar 41 ... Steel pipe (formwork)
42 ... Concrete 43 ... Concrete body 50 ... Temporary scaffolding 51 ... Tumble prevention wire 52 ... Crane 53 ... Steel tape

Claims (3)

A method of placing concrete in a pillar,
Preparing a concrete placing jig comprising a hopper for containing concrete, and a cylindrical and flexible concrete supply pipe extending from the hopper and having at least a part of inner surfaces in close contact with each other,
Building the pillar formwork;
Placing the hopper directly above the formwork, and placing the concrete supply pipe along the column axis in the formwork;
Dropping the concrete in the hopper into the mold through the inside of the concrete supply pipe. A cap is attached to the tip of the concrete supply pipe,
The concrete placing method according to claim 1, wherein a plurality of openings are formed in the cap.   The concrete placing method according to claim 2, wherein the cap and the hopper are connected by a wire.

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