JPH05287802A - Construction method of centrifugal casting pca column - Google Patents

Abstract

(57) [Summary] [Purpose] When using a cylindrical precast concrete member that has been centrifugally molded as a pillar material, it is possible to reduce the work amount of reinforcing bars on the site and improve workability. [Structure] A tubular precast concrete member 5 is a steel plate in which a column main bar 6 embedded in a concrete part 8 is vertically projected through and a periphery of a projecting portion 6a at the lower part of the column main bar 6 is connected to a lower end of the concrete part 8. 9 or the lower end of the concrete part is surrounded by an integral concrete plate with a steel plate inside, and concrete is placed inside the precast concrete member 5 by using this as a lap joint part between the column main bars of the lower layer column and the upper layer column.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal molding PC which uses a cylindrical precast concrete member (PCa column) centrifugally molded when constructing a building or a structure.
a The column construction method.

[0002]

2. Description of the Related Art As a construction method that does not require support work, there is a construction method in which a cylindrical precast concrete member (PCa column) that is centrifugally formed is used as a pillar material. As shown in FIG. The precast concrete (PCa) member 1 is built in, and the column main bar 2
And the concrete is placed to form an RC structure.

The method of adding the column main bars 2 may be such that the column main bars 2 are connected in advance by pressure welding, welding, and mechanical joints, and the outside thereof is covered with the precast concrete (PCa) member 1, as shown in FIG. In some cases, a lap joint may be formed inside the precast concrete (PCa) member 1. In the case of such a lap joint, the restraint iron plate 3 is provided on the outer periphery thereof.
To arrange. Reference numeral 4 in the drawing denotes a hoop streak that is embedded in advance when the tubular precast concrete (PCa) member 1 is centrifugally molded.

[0004]

Thus, in the conventional method of using the centrifugally molded tubular precast concrete member as the pillar material, the cylindrical precast concrete member and the column main bar are separate entities, The on-site bar arrangement was troublesome.

An object of the present invention is to provide a centrifugal molding PCa column construction method capable of solving the above-mentioned disadvantages of the conventional example and reducing the work amount of the reinforcing bar on the site and improving the workability.

[0006]

In order to achieve the above-mentioned object, the present invention uses a centrifugally molded tubular precast concrete member as a pillar material, in which the precast concrete member is a pillar main bar embedded in a concrete portion. Surround the projecting outer part of the lower part of the column main bar with a steel plate that joins the lower end of the concrete part or a concrete plate with a steel plate inside that is integrated with the lower end of the concrete part. As a lap joint part of the above, the gist is to place concrete inside the precast concrete member.

[0007]

According to the first aspect of the present invention, the column main bar is pre-embedded in the centrifugally formed tubular precast concrete member used as the column member when the column-shaped precast concrete member is centrifugally formed.
In addition, this pillar main bar is free in the part projecting above and below the concrete part. Therefore, when the centrifugally molded tubular precast concrete member is built, the column main reinforcement of the lower column is inserted into the portion surrounded by the steel plate under the precast concrete member. It is possible to form a lap joint with the main bar protrusions at the lower part of the part. Further, the steel sheet acts as a formwork during concrete pouring and as an internal concrete restraint member.

According to the second aspect of the present invention, in addition to the above-mentioned action, the lower part of the precast concrete member is surrounded by the concrete plate with the inside of the steel plate, so that no fireproof coating is required for this part, and the surface of the column is also finished. No hassle.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a vertical sectional side view showing an example of a centrifugally-molded tubular precast concrete member (PCa column) used in the centrifugally-molded PCa column method of the present invention.
3 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a sectional view taken along the line BB of FIG.

In the figure, reference numeral 5 denotes a centrifugally molded tubular precast concrete member (PCa column), in which a column main bar 6 and a band bar 7 surrounding its outer circumference are formed in a centrifugally molded concrete part 8 having a circular hollow cross section. Buried. Then, the pillar main bars 6 are projected through the top and bottom of the concrete portion 8.

Further, the protruding portion 6a at the lower portion of the column main bar 6 is provided.
The outer circumference of was surrounded and bent by the steel plate 9 connected to the lower end of the concrete portion 8.

FIG. 4 is a perspective view of a member constituting the steel plate 9 portion, which is a steel box body 10 having an open lower surface, the inside of which is partitioned by a vertical partition plate 11 into a cross shape, and the upper surface of which has an opening 12 at the center. The top plate 13 has a peripheral edge. This top plate 13 has a tapered shape that rises toward the opening 12 in order to improve the filling property when pouring concrete inside, and a hole 14 for penetrating the main bar is formed.
Is provided.

Further, the steel box body 10 has an anchor streak 15 having a hook at its tip and is erected upward, and steel plate legs 16 are provided on the lower surfaces of the intersections of the partition plates 11.

Such a steel box body 10 is preliminarily formed together with the reinforcing bar in advance by making the column main bar 6 penetrate through the hole 14 when centrifugally forming the cylindrical precast concrete member (PCa column) 5. When set in the formwork of No. 3, it is integrally connected to the lower end of the concrete portion 8 of the precast concrete member 5.

As shown in FIG. 5, the column main bar 17 of the lower layer column 19 has its upper portion projecting above the beam / floor 18.
When the centrifugally molded tubular precast concrete member 5 is to be built, if it is inserted into the lower part surrounded by the steel plate 9, the main pillars 17 of this lower layer pillar and the lower part of the concrete part 8 The protruding portion 6a of the main bar 6 which is free can be configured as a lap joint. The steel plate feet 16 are useful for ensuring the stability of the standing when the precast concrete member 5 is built on the beam / floor 18. In order to form a lap joint without fighting with the lower layer column main reinforcement 17 and the upper layer column main reinforcement 6, the main reinforcement 6 is arranged in an inclined manner in the concrete portion 8.

After that, when concrete is poured into the precast concrete member 5 from above, the concrete is also filled in the steel plate 9 through the opening 12, and the steel plate 9 is used as a mold for concrete pouring. Acts as a frame and as a restraint for internal concrete. Since there is the steel plate 9, it is not necessary to apply streaks to this portion.

Further, if the shape of the steel box body 10 of this steel plate 9 is made smaller than the cross-sectional dimension of the column by a few centimeters, the outside thereof may be subjected to a fireproof coating as a post-treatment.

FIG. 6 is a vertical cross-sectional side view showing another example of a centrifugally-formed tubular precast concrete member (PCa column) used in the centrifugally-formed PCa column method as a second embodiment of the present invention. And the stirrup 7 surrounding the outer circumference thereof are embedded in a centrifugally molded concrete part 8 having a circular hollow cross section inside, and the column main bar 6 is projected above and below the concrete part 8 in the first embodiment. Same as the example, but with the protrusion 6a at the bottom of the column main bar 6
The outer periphery of the concrete part 8 was surrounded by a concrete plate 21 in which a steel plate 20 integral with the concrete part 8 was attached.

As shown in FIG. 9, a member made of the steel plate 20 is a steel box 10 having an open lower surface, and the upper surface is closed by a top plate 13 having an opening 12 at the center. This top plate
Reference numeral 13 is a tapered shape that rises toward the opening 12. A hole 14 is provided for penetrating the main muscle, and the anchor muscle 15 is erected upward. In order to increase the adhesion with concrete,
A striped steel plate is used for the steel plate 20. A small hole 22 for water permeation is provided on the side of the steel box body 10.

The steel box 10 is used for centrifugally molding a tubular precast concrete member (PCa column) 5.
As shown in FIG. 11, the inner mold is set in the outer mold 23 of the centrifugal manufacturing apparatus. In the figure, reference numeral 24 is an auxiliary outer formwork extending to the end of the outer formwork 23, and 25 is an auxiliary inner formwork temporarily provided at the end of the steel box 10.

Outer form 23 and auxiliary outer form 24 and steel box 10
Concrete is poured from both ends between the space and the side pressure generated by centrifugal force and the fluidity of the concrete (centrifugal acceleration during centrifugal production reaches 20 to 30 G, so pressure is usually 20 to 30 times that of gravity). Thus, the entire area of the outer circumference of the steel box body 10 is filled with concrete. The air and water at the time of placing the outer peripheral concrete are discharged to the inside of the steel box body 10 through the small holes 22.

After casting and curing, as shown in FIG. 12, the auxiliary outer mold 24 and the auxiliary inner mold 25 are removed, and the molded extra concrete block is removed.

In this way, when the precast concrete member (PCa column) 5 is centrifugally formed, the steel box 10 is made to penetrate the column main bar 6 through the hole 14 so that the frame of the centrifugal manufacturing apparatus can be prepared together with the reinforcing bar in advance. If set to, the precast concrete member 5 is integrally joined to the lower end of the concrete portion 8.

As shown in FIG. 10, when the cylindrical main cast 17 of the lower pillar 19 is built into the cylindrical precast concrete member 5, the steel plate 20 is surrounded by the concrete plate 21. If it is inserted into the portion, the column main bar 17 of this lower layer column and the projecting portion 6a of the free main bar 6 below the concrete portion 8 can be configured as a lap joint. In order to form a lap joint without fighting with the lower layer column main reinforcement 17 and the upper layer column main reinforcement 6, the main reinforcement 6 is arranged in an inclined manner in the concrete portion 8.

After that, when concrete is poured into the precast concrete member 5 from above, the concrete is also filled into the concrete plate 21 to which the steel plate 20 has been adhered through the opening 12 and the steel plate 20. Acts as a formwork when placing concrete and as a restraint member for internal concrete. And this part is a concrete board
Since 21 is present, there is no need to apply a fireproof coating as a post-treatment, and since there is a steel plate 20, there is no need to apply stirrup.

[0026]

As described above, the centrifugal molding PC of the present invention
The a-column method can reduce the work amount of the reinforcing bar at the site and improve the workability when the centrifugally molded tubular precast concrete member is used as the pillar material.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an example of a centrifugally molded tubular precast concrete member (PCa column) used in a centrifugally molded PCa column method of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a perspective view of a member forming a steel plate portion.

FIG. 5 is a partially cutaway front view showing the first embodiment of the present invention.

FIG. 6 is a vertical cross-sectional side view showing another example of a centrifugally molded tubular precast concrete member (PCa column) used in the centrifugally molded PCa column method of the present invention.

FIG. 7 is a sectional view taken along line CC of FIG.

8 is a cross-sectional view taken along line DD of FIG.

FIG. 9 is a perspective view of a member that constitutes an inner laminated steel plate.

FIG. 10 is a partially cutaway front view showing a second embodiment of the present invention.

FIG. 11 is a vertical cross-sectional front view of the first step showing the manufacturing process of the concrete plate portion having the steel plate internally attached.

FIG. 12 is a perspective view of a second step showing the manufacturing process of the concrete plate portion in which the steel plate is stuck.

FIG. 13 is a vertical sectional side view showing a conventional example.

FIG. 14 is a cross-sectional plan view showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Precast concrete member 2 ... Column main reinforcement 3 ... Restraint iron plate 4 ... Hoop reinforcement 5 ... Cylindrical precast concrete member 6 ... Column main reinforcement 6a ... Projection 7 ... Belt reinforcement 8 ... Concrete part 9 ... Steel plate 10 ... Steel box Body 11… Partition plate 12… Opening 13… Top plate 14… Hole 15… Anchor bar 16… Steel plate leg 17… Column main bar 18… Beam / floor 19… Lower column 20… Steel plate 21… Concrete plate 22… Small hole 23… Outside Formwork 24 ... Auxiliary outer formwork 25 ... Auxiliary inner formwork

Claims (2)

[Claims] 1. In the case where a centrifugally molded tubular precast concrete member is used as a pillar material, the precast concrete member vertically protrudes through a pillar main bar embedded in a concrete portion, and a protruding portion at a lower portion of the pillar main bar. A centrifugal molding PCa column construction method characterized in that the outer periphery is surrounded by a steel plate that is joined to the lower end of the concrete portion, and this is used as a lap joint between the main reinforcements of the lower and upper columns, and the concrete is placed inside the precast concrete member. 2. When a centrifugally molded tubular precast concrete member is used as a pillar material, the precast concrete member vertically protrudes through a column main bar embedded in the concrete portion, and a projecting portion below the column main bar. Centrifuge characterized by placing concrete inside the precast concrete member by surrounding the outer periphery with a concrete plate with a steel plate inside which is integrated with the lower end of the concrete part, and using this as a lap joint part between the main reinforcements of the lower and upper columns Molding PC
a Column construction method.