JPH02217543A - Constructing method for centrifugal forming steel bar reinforced concrete - Google Patents

Abstract

PURPOSE:To transfer axial force of columns with certainty by providing a plurality of the first and the second reinforcing bars to the insides of the first and the second steel pipes, and connecting the first and the second concrete members provided with the first and the second lining concrete by centrifugal forming. CONSTITUTION:The first twelve reinforcing bars 2 are provided to the first column H1 in the circumferential direction of the first steel pipe 1, and the first reinforcing bars 2 are enveloped in the first lining concrete 3 by centrifugal forming. The second reinforcing bars 12 are extended and provided to the inside of the second steel pipe 11 of the second column H2 so that they have a length to project out of the ends of the second steel pipe 11 and, at the same time, they are enveloped in the second lining concrete 3. Furthermore, internal form members 14 are fixed to the second steel pipe 11, and the columns H1 and H2 are positioned to pour and fill mortar into spaces S. Accordingly, the axial force and moment acting on the up and down columns H1 and H2 can be transferred.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a centrifugally formed steel rod that is used as a pillar or flexible structural member of a building and is assembled by connecting centrifugally formed steel rod reinforced concrete covered with a steel pipe. This relates to a method of constructing reinforced concrete.

"Conventional technology and its problems" Conventionally, this type of centrifugally formed steel rod reinforced concrete construction method has not been known, and similar technologies include reinforced concrete (RC) and steel reinforced concrete (SRC).
Construction methods for concrete piles and steel pipe concrete piles are known.

The RC construction method and the SRC construction method are constructed by arranging reinforcing bars, surrounding them with formwork on site, and then filling the inside of the formwork with concrete.

In other words, in these RC and SRC construction methods, for example, when connecting members such as columns and beams in the middle, the reinforcing bars protruding from the end faces of the upper and lower columns are connected using couplers, etc. The connection is made by covering the surrounding area with a formwork at the construction site and filling the inside of the formwork with mortar or the like.

However, the above-mentioned RC construction method and SRC construction method require the work of assembling formwork at the construction site and the work of pouring a large amount of concrete on-site, and in recent years the construction cost has increased due to a shortage of workers. This required a lot of manpower, construction time, construction costs, etc., and there were problems in construction management.

Furthermore, as for centrifugally formed steel rod reinforced concrete, it is known that it is applied to steel pipe concrete piles, and the steel pipe concrete piles are made by incorporating reinforcing bars inside the steel pipes and then filling the insides of the steel pipes with concrete. This was then constructed by centrifugal molding.

However, with these steel pipe concrete piles, when the piles are connected in the middle, only the steel pipe parts are welded together, and the stress transmission between the members is not sufficient. There are difficult quality control issues, such as the high temperatures during welding having an adverse effect on the internal concrete. Therefore, no technology has been established regarding a construction method that does not cause problems in terms of construction control certificates and quality control, which is the object of the present invention.

The present invention has been made in view of the above-mentioned problems, and allows centrifugally formed steel rod reinforced concrete members to be used as a building structure, and allows the centrifugally formed steel rod reinforced concrete members to be easily connected to each other, and also enables the use of centrifugally formed steel rod reinforced concrete members as a building structure. The object of the present invention is to provide a method for constructing centrifugally formed steel rod reinforced concrete that can reliably transmit axial force and that does not cause problems in quality control.

"Means for Solving the Problems" This invention provides a first steel pipe having a predetermined length, which extends in the axial direction with approximately the same length as the first steel pipe, and extends along the circumferential direction. A plurality of first reinforcing bars are provided at predetermined intervals, and the first reinforcing bars are further enclosed by centrifugal forming and retreated by a predetermined distance from both ends of the first steel pipe inward to form a first lining. While manufacturing a first centrifugally formed steel bar reinforced concrete member coated with concrete, the first lining concrete is applied to the inside of a second steel pipe of a predetermined length from both ends of the second steel pipe. It protrudes to a length approximately equal to the receding dimension from both ends of the
A plurality of second reinforcing bars are provided at predetermined intervals along the circumferential direction at different positions in the radial direction of the steel pipe from the first reinforcing bars, and further, second reinforcing bars are formed by centrifugal forming to enclose the second reinforcing bars. A second centrifugally formed steel rod reinforced concrete member with lining concrete of No. 2 was manufactured, and these
After placing one of the centrifugally formed steel rod reinforced concretes, the other is brought into contact with the steel pipe joint, and then between the first and second lining concrete of the first and second centrifugally formed steel pipe reinforced concretes. The above-mentioned problem is solved by filling the gap formed by mortar with mortar.

"Operation" Since the centrifugally formed steel rod reinforced concrete of the present invention is configured as described above, after the second centrifugally formed steel rod reinforced concrete is placed, the first
When the centrifugally formed steel rod reinforced concrete member comes into contact with the first and second lining concrete members, a second reinforcing bar protruding from the second steel pipe is placed in the gap formed between the first and second lining concrete members. By overlapping the reinforcing bars and the second reinforcing bars at different positions in the radial direction and filling the gap with mortar, the first reinforcing bars and the second reinforcing bars are fixed, forming a lap joint, and the first and second reinforcing bars are overlapped. Centrifugally formed steel rod reinforced concrete members are mechanically connected. In this state, if the first steel pipe and the second steel pipe are butt welded, the first and second centrifugally formed steel rod reinforced concrete members will be more firmly connected and constructed. Become.

"Example" The present invention will be described below with reference to the drawings.

Figures 1 to 6 show an embodiment in which the centrifugally formed steel rod reinforced concrete construction method of the present invention is applied to columns, and the reference numeral H in the figures indicates a centrifugally formed steel rod reinforced concrete column (
(hereinafter simply referred to as "pillars").

First, the outline of the first pillar H1 used in the construction method of this embodiment will be explained using FIG.
1 extends in the axial direction with approximately the same length as the first steel pipe 1 inside a first steel pipe l having a predetermined length, and extends at regular intervals along the circumferential direction of the first steel pipe l. Twelve first reinforcing bars 2 are provided. The first reinforcing bars 2 are contained inside a first lining concrete 3 formed by centrifugal forming, and the first lining concrete 3 is moved inward from both ends of the first steel pipe 1 in a predetermined direction. The dimensions have been set back.

And the setback lining concrete 3
A slope is formed that gradually expands in diameter as it approaches the outside of the steel pipe, and both ends of the first reinforcing bar 2 protrude from the slope to near the end surface of the first steel pipe l. ing.

Next, referring to FIG. 6, the second column H2 will be explained. The second column H2 has a second reinforcing bar 12 inside a second steel pipe 11 of a predetermined length. 11, extending in the axial direction with a length protruding from both ends, and 12 of them are arranged at regular intervals in the circumferential direction. Further, the second reinforcing bars protrude from both ends of the steel pipe with lengths slightly shorter than the setback length of the first lining concrete, and the first reinforcing bars 2 are arranged. It is provided so as to be located closer to the center of the steel pipe 11 than in the radial direction. The second reinforcing bars 2 are made of second lining concrete 1.1 formed by centrifugal forming.
It is included inside 3. Further, at both ends of the second steel pipe 11, an end plate 14a and a cylindrical member +4b are provided.
An inner formwork member I4 formed by the above is fixed, and the inner formwork member 14 aligns the columns H1 and H2 by fitting inside the first lining concrete, and It is configured to serve as a formwork for injecting mortar into the gap S formed by the inner formwork member and the steel pipe I. In addition, near the tip of the cylindrical member 14b of the inner frame member 14, an air vent hole h2 as described later is formed.

Next, the first and second centrifugally formed steel rod reinforced concrete columns 1 and H2, which are configured as shown in the figure, are located at the midpoint of the columns (i.e., near the inflection point of the moment applied to the columns). The connected state will be explained using FIG. 1 and FIG. 2(a).

The upper end of the inner formwork member 14 fixed to the upper part of the second pillar H2 is fitted into the lower end of the first lining concrete 3 formed on the inner peripheral surface of the first pillar H1, In the annular gap S defined by the inner formwork member 14, the steel pipe 1, and the first lining concrete 3, there is a lower end of the first reinforcing bar 2 extending from above to below, and a lower end of the first reinforcing bar 2 extending from below to above. The upper end portion of the second reinforcing bar I2 is placed at a different position in the radial direction (double in a shape that surrounds the center on a plane with the central axis of the Li pipe as the center).

And the corresponding number! , second reinforcing bar 2. ■By filling the mortar M into the gap S in which the first and second
The second reinforcing bar is mechanically connected in a lap joint.

Further, the end faces of the first steel pipe 1 at the upper part and the second steel pipe 2 at the lower part are welded together.

Therefore, in the column H of this embodiment, the upper and lower columns H1,i
(The axial force and moment acting on 2 can be transmitted.

Next, the procedure for carrying out the construction method of the centrifugally formed steel rod reinforced concrete column of this embodiment on site will be explained using FIGS. 3 and 4(a).

(i) First, as shown in FIG. 3, the first column H1 is placed on top of the second column H2 manufactured as described above, with its central axis aligned.

(11) Next, as shown in Fig. 4(a), the column 1-TI is built on the top of the second column 1-12, and the steel pipes at the tips of the first steel pipe and the second steel pipe are These steel pipes are connected by butt welding the joints.

At this time, the tip of the inner formwork member 14 is fitted near the upper end of the first lining concrete, and there is a gap between the inner formwork member, the first steel pipe, and the lining concrete 3. A gap S is formed, and the first reinforcing bar 2 and the second reinforcing bar 12 are arranged in the gap S in a lap joint state.

(iii) Next, after forming a mortar injection port h1 near the bottom of the first steel pipe H1 using an electric drill or the like,
The gap S is filled with mortar through the injection port h1, and the mortar is flowed out through the exhaust port h2 of the mold member that has already been formed, resulting in the state shown in FIG. 1.

In this way, in the centrifugally formed steel rod reinforced concrete construction method of the present invention, when the upper column HI is built into the lower column H2, the inner formwork member 14 is inserted into the lining concrete 3 of the first steel pipe. This is a construction method that allows easy alignment by fitting the inner formwork member, the first steel pipe, and the first lining concrete, and a gap S is formed between the inner formwork member, the first steel pipe, and the first lining concrete, and the inside of the gap S is The first reinforcing bar and the second reinforcing bar are fixed in the gap by mortar, creating a lap joint, which transmits the axial force and moment of the first and second columns without directly connecting the reinforcing bars. be able to.

Therefore, in the case of this embodiment, there is no need to assemble a formwork, and the columns H1 and H2 can be mechanically and strongly connected, improving workability and reducing construction costs. . Note that the columns H in this example are connected at the middle point of the columns, which is the point of inflection of the moment.
The structure is said to be strong enough.

In addition, after installing pillars H1 and H2, the pillar HIj(2
Of course, the strength of the column can be improved by filling the inside of the lining concrete with concrete.

Further, in the above embodiment, the column H1 is built above the column H2, but the present invention is not limited to this, and the column H1 is built above the column H1.
2 may be built in.

In addition to carrying out the construction method of the present invention as a pillar as described above, it can also be constructed similarly as a beam member.

In other words, it is sufficient to implement the vertical relationship in the above embodiment as a horizontal relationship.

Note that the cross section of the member is not limited to a circular shape, as shown in Fig. 2(b).
It may also be polygonal, as shown in .

In addition, a column T is placed above the second column H2 shown in FIG. 4(a).
-11, and connect the first and second steel pipes by butt welding the joints at the tips of the first and second steel pipes, as shown in Fig. 4(b). The lining concrete 3 of the first column H1 is shaped so that it slopes upward as it goes outward, and the steel pipe 1 is positioned directly below the lining concrete.
If the air vent hole h2 is formed in the steel pipe, when the gap S formed inside the steel pipe is filled with mortar, air will be sufficiently removed and filling with mortar will be performed satisfactorily.

Further, the inner frame member is not limited to the shape described above, and the design can be changed as appropriate.

"Effects of the Invention" As explained above, in the method for constructing centrifugally formed steel rod reinforced concrete of the present invention, the first lining is set back inward from both end surfaces of the first steel pipe by a predetermined length. Concrete is applied, and second reinforcing bars are provided by protruding from both end faces of the second steel pipe by the amount by which the first lining concrete is set back, and these first centrifugally formed steel rod reinforced concrete and second After erecting the centrifugally formed steel rod reinforced concrete, the first reinforcing bars and the second reinforcing bars are fixed with mortar.
Unlike conventional construction methods, there is no need for formwork assembly and dismantling work, making it possible to significantly reduce construction costs and the number of workers, as well as shorten the construction period. In addition to being used as columns and beams, members can be easily connected in the middle of the members.
Moreover, it is possible to reliably transmit the force acting on the member, that is, the moment and the axial force, to the other member.

[Brief Description of the Drawings] Figures 1 to 6 show one embodiment of the present invention, and Figure 1 shows the main part of the method for constructing a centrifugally formed steel rod reinforced concrete column of the present invention. Fig. 2(a) is a side sectional view of the column, and Fig. 2(a) is a plan view of a circular column showing the cross section taken along ■-■ in Fig. 1. Fig. 2(b) is a side sectional view showing the cross-section taken along ■-■ in Fig. 1. Figure 3 is a side cross-sectional view of the pillar showing the alignment of the first pillar to the second pillar, and Figure 4 (a) is a plan view of the pillar with the first pillar aligned with the second pillar. Fig. 4(b) is a side sectional view of another embodiment showing the state in which the first pillar is built into the second pillar; FIG. 6 is a side sectional view of the manufactured first pillar, and FIG. 6 is a side sectional view of the second pillar manufactured by centrifugal molding. Line, 13...Second lining concrete,
14... Inner formwork member.

Claims (1)

[Claims] A plurality of first reinforcing bars extending in the axial direction with substantially the same length as the first steel pipe and arranged at predetermined intervals along the circumferential direction inside the first steel pipe having a predetermined length. and further includes the first reinforcing bar by centrifugal forming and the first reinforcing bar.
A first centrifugally formed steel rod-reinforced concrete member is manufactured by recessing a steel pipe a predetermined distance inward from both ends and applying a first lining concrete. The first lining concrete protrudes from both ends of the second steel pipe to a length that is approximately the same as the receding dimension from both ends of the first steel pipe, and is located at a different position in the radial direction of the first reinforcing bar and the steel pipe. A second centrifugally formed steel rod having a plurality of second reinforcing bars arranged at predetermined intervals along the circumferential direction, and further provided with a second lining concrete by centrifugal forming so as to enclose the second reinforcing bars. After manufacturing a reinforced concrete member and placing one of these first and second centrifugally formed steel rod reinforced concrete members, the other one is brought into contact with the joint portion of the steel pipe, and then the first and second centrifugally formed steel pipes are connected to each other. A method for constructing centrifugally formed steel rod reinforced concrete, which comprises filling a gap formed between first and second lining concrete of reinforced concrete with mortar.