JPH02104852A - Precast concrete post - Google Patents

Abstract

PURPOSE:To improve execution efficiency by passing through sheats for inserting post main bars into a steel shell form lengthwise in the circumferential direction at intervals to place them and placing concrete to form a post while rotating the shell form. CONSTITUTION:Sheaths 3 for inserting post main bars 5 into a steel shell form 2 are passed through lengthwise in the circumferential direction at intervals to place them, and concrete is placed to form a precast concrete post 1 while rotating the form 2. In case of field work, a group of post main bars 5 is connected to a group of floor side main bars in advance. After that, the precast concrete post 1 is moved to a construction point, an opening of the lower part of each of the sheaths 3 is put together with the post main bars 5 connected to the floor main bars to lower the post 1, and grouting into the sheaths 3 of the post 1 is made. According to the constitution, the high strength of connection can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a precast concrete column that is easy to construct on-site.

(Prior art) When constructing columns in a building under construction, in recent years, a part or all of the reinforced concrete columns are manufactured in a factory, and these precast concrete columns (hereinafter referred to as rPC columns) are placed at the construction site. A construction method has been adopted that aims to improve work efficiency by quickly constructing reinforced concrete columns.

Construction methods for such PC columns, especially on-site construction methods for joints between main reinforcements, include pressure welding, mechanical joints using screws, or metal sleeves (Japanese Patent Laid-Open Publication No. 130838/1983). It has been known.

First, the structure and construction method of the PC column in the case of mechanical connection using screws will be explained with reference to FIG.

In the same figure, the PC pillar 11 mainly consists of the concrete body 12
and a column main reinforcing group 13 in the concrete body 12, and the column main reinforcing group 13 protrudes from both end faces of the concrete body 12 by a certain length in the axial direction of the concrete body 12.

During construction, we first installed the PC pillar 1 manufactured at the factory.
1 is moved to the construction site using a crane or the like at the construction site. Next, the tips of the main reinforcement groups 13 of the columns 13 and the tips of the main reinforcement groups 14 of the r:t·5 law, which are constructed so as to protrude from the floor surface 15 by a certain length in accordance with the arrangement of the main reinforcement groups 13 of the columns, are connected. (-21- The column main reinforcement group 13 and the body side main reinforcement group 14 are mechanically connected, and then the formwork 16 is erected between the bottom surface of the PC column 11 and the floor surface 15, and then the concrete After pouring on site and solidifying the concrete, jP!l?416 is removed to complete the PCCl2O construction.

Next, I will explain what uses sleeves (C
Columns mainly consist of a concrete body, a group of column main reinforcements installed inside the concrete body, and are buried at the legal lower end of the concrete body, and the lower ends of the column main reinforcements and the upper ends of the body side main reinforcements that are butted are placed inside the concrete body. It consists of a group of 8f sleeves. Specifically, the tips of the lower ends of the main column reinforcements reach halfway into the sleeves, and the lower ends of each sleeve are opened at the bottom surface of the concrete body in correspondence with the main reinforcements on the body side.

To construct the PC pillar, first, the PC pillar manufactured at the factory is moved to the construction site using a crane or the like at the construction site. Next, the body side main reinforcement, which has been constructed in advance to protrude from the floor by a certain length in accordance with the arrangement of these sleeves, is fitted into the frontage of section F of the sleeves. Then, a grouting agent such as mortar is injected into the inside of the PC pillar, and the construction of the PC column, especially the connection part, is completed.

(Problem to be Solved by the Invention) However, in construction using the mechanical joint shown in FIG. 6, it is difficult to adjust and connect the screw threads of the fixed reinforcing bars of both the column main reinforcement group 13 and the body side main reinforcement group 14. The floor height is difficult to adjust. In addition, the direction in which each column main reinforcement 13 protrudes from the bottom surface of the concrete body 12 and each body side main reinforcement 14
If the direction of the protrusion is not the desired direction, the direction of the upper and lower reinforcing bars will be misaligned, or the lower tips of each column main reinforcement 13 and the tips of each body side main reinforcement 14 will not all butt up, resulting in PC
This causes the inconvenience that the Cl2O bonding strength cannot be ensured.

In addition, concrete must be placed in that area after the reinforcing bars are joined, and the work is time-consuming because it is reverse-cast concrete.Also, the above-mentioned problems do not occur with sleeves. In some cases, the grouting agent does not sufficiently spread into each sleeve, resulting in the inconvenience that the bonding strength of the PC pillars cannot be ensured. Furthermore, this method cannot be used in areas where the upper and lower reinforcing bars are not directly connected to each other and where the reinforcing bars will yield and require large deformability.

Furthermore, when pressing the fixed reinforcing bars of both the column main reinforcement group 13 and the body side main reinforcement group 14, the pressed reinforcing bars will shrink, so it is necessary to install all the reinforcing bars at the same time, which is actually impossible.

The present invention has been proposed in order to solve the above problems, and is a PC system that does not require the erection of column forms or the on-site pouring of concrete, has good workability, and can obtain high joint strength. The purpose is to provide a pillar.

(Means for Solving the Problems) The present invention provides for a PC column to be centrifugally formed, in which sheaths for inserting column main reinforcement into the outer shell formwork are penetrated at intervals in the circumferential direction and in the longitudinal direction. At the same time, concrete is poured into the outer shell formwork while rotating it and centrifugally formed.

Preferably, the outer shell formwork is made of steel.

(Function) To describe the function of the present invention, during on-site construction, the column main reinforcement group is connected in advance to the body side main reinforcement group protruding from the floor by pressure welding, welding, or a mechanical method, and then the PC column having the above structure is connected. Move the PC column to the construction site, then align the lower opening of each sheath that runs along the circumferential direction of the column and penetrates in the longitudinal direction with the column main reinforcement connected to each body side main reinforcement, and finally lower the PC column. By doing so, each column main reinforcement is fitted into each sheath.

Alternatively, each column main reinforcement is inserted in advance into each sheath of the PC column and temporarily fastened, and with the column suspended, each column main reinforcement is pressed or welded to each body side main reinforcement that protrudes from the floor. The temporary fixing is released during or after the pressure welding or welding. Then lower the PC pillar.

After any of the above operations, grout is injected into each sheath of the grounded PC column. This grout injection is
Do this until it overflows from the top of each sheath.

After the grout has solidified, the joint strength of the PC columns is ensured by the column main reinforcement that is pressed or welded to the body side main reinforcement and the filled grout.

(Example) First, an example of the PC pillar of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the present invention is basically a PC column that is centrifugally formed, in which column main reinforcements are placed inside the outer shell form 2.
Sheaths 3 for insertion are arranged at intervals in the circumferential direction and penetrated in the longitudinal direction, and concrete 4 is poured into it while rotating the outer shell form 2 and formed by centrifugal molding. . In FIG. 1 of this embodiment, the outer shell form 2 has a circular cross section, and the cylindrical PCC 10
It has become. On the other hand, FIG. 3 shows a case where an outer shell form 2 having a square cross section is used.

In either case, both ends of each sheath 3 are opened at both longitudinal end surfaces 1a, if of the PCC 10. This P
To briefly describe CC10 molding, concrete 4 is poured into the outer shell form 2 based on the centrifugal molding method, and the outer shell form 2 is rotated around its longitudinal axis. This results in
A centrifugal force acts on the concrete 4 to form a concrete body having a hollow portion 6 within the outer shell form 2, and then the concrete 4 is solidified. PCC1 according to the invention
If 0 is used, there is no need to process, install, or remove formwork on site, and the associated costs can be reduced.

Next, a method of constructing the PCC 10 will be explained with reference to FIG.

First, the upper tips of each body side main reinforcement 14 protruding from the floor and the lower tips of each column main reinforcement 5 are butted together, and the legal example main reinforcement group 14 and the column main reinforcement group 5 are joined by pressure welding, welding, or other mechanical joints. Next, move the PC column 1 above the construction point, align the lower opening of each sheath 3 with the upper tip of each column main reinforcement 5, and then lower the PC column 1 to attach each column main reinforcement to each sheath group 3. Insert group 5.

Alternatively, as shown in Fig. 5, each column main reinforcement 5 is installed in advance.

It is inserted into each sheath 3 so that its lower tip protrudes a certain length from the bottom surface of the PCC 10, and is temporarily fixed so that each column main reinforcement 5 does not fall. In this state, move the PCC10 to the construction site, temporarily install the PCC10, match the lower tips of the temporarily fastened column main reinforcements 5 with the upper tips of each body side main reinforcement 14 protruding from the floor, and match the column main reinforcement group 5 and the method example main reinforcement group. 14 by pressure welding, welding, or the like. After that, the temporary fixing of each column main reinforcement 5 is released and the PCC 10 is lowered and placed in a predetermined position. Thereafter, a grouting agent 26 such as mortar is filled and injected into each sheath 3. The grouting agent 26 is injected until it overflows from the upper part of the sheath 3.

In this way, the joint strength to the floor surface 15 of the PCC 10 can be increased between the press-welded or welded column main reinforcement group 5 and the column main reinforcement group 14.
, since they are integrated by the grouting agent 26 etc. injected into each sheath 3, the strength of the PCC 10 member can be ensured.

In the embodiments shown in FIGS. 1 and 3, the P and C pillars 1 are described as having a hollow cylindrical shape. good.

Further, the cross-sectional shape of the PCC 10 depends on the outer shell formwork 2, and its shape is not limited.

Moreover, when further increasing the strength of the hollow cylindrical PCC 10 shown in FIGS. 1 and 3, post-casting of concrete may be performed in the hollow portion 6 of the PCC 10 after the construction of the PCC 10.

As explained above, since a plurality of sheaths 3 that penetrate in the axial direction are provided inside the PC column 1, the column main reinforcement 5, which has been pressure-welded or welded to the body side main reinforcement 14 in advance, is inserted into the column 1 later. The joining work can be performed by fitting or temporarily fastening, and the body side main reinforcement 14 and the column main reinforcement 5 can be reliably joined.

Unlike the conventional construction of PC columns using sleeves, the present invention has high reliability in ensuring the strength and deformation of the members because the reinforcing bars are joined together. In addition, there is no need to carry out mechanical joining such as conventional difficult butting of the lower end of the column main reinforcement and the upper end of the body side main reinforcement, and the effort of post-casting concrete can be saved. Furthermore, in the mechanical joint construction method, there is a risk that the PC column may be misaligned in the vertical direction when constructing the PC column, but this can be resolved by using the PC column according to the present invention.

In addition, the PCC 1 is equipped with a plurality of sheaths 3 by centrifugal molding.
0, it is possible to pour concrete densely, and since the hollow part 6 can be formed inside, ff1fl is small (,
Work such as hanging becomes easier.

In particular, by making the outer shell formwork 2 that forms the outer shell made of steel, it is possible to prevent brittle fracture after the maximum strength when ultra-high strength concrete is used, and to provide the column 1 with toughness.

Furthermore, if steel pipes are used for the steel formwork 2, the manufacturing process, especially the manufacturing, assembly, and disassembly of the formwork, will be simplified, reducing production costs and improving production efficiency.

(Effects of the Invention) In the present invention, since a plurality of sheaths communicating in the axial direction are provided in the concrete body of the PC column, the column main reinforcement that has been pressure-welded, welded, or mechanically joined to the main reinforcement on the body side in the sheath is later connected to the PC column. It is possible to carry out the joining work by inserting it into the column or temporarily fixing it, and it is possible to appropriately and sufficiently ensure the connection between the body side main reinforcement and the column main reinforcement.

As a result, a structure in which the PC columns are integrated with the main reinforcing bars can be created, and vertical displacement of the PC columns does not occur.

In addition, since the PC column is made of a plurality of sheaths formed by centrifugal molding, the concrete is dense, and since it has a hollow section, it is light in weight and easy to hang.

Furthermore, according to the present invention, the PC column can also be used as a formwork, so that the on-site process does not require processes such as manufacturing, assembling, and dismantling the formwork, thereby reducing construction costs and improving construction efficiency. .

[Brief explanation of drawings]

FIG. 1 is a plan sectional view showing an embodiment of the PC pillar of the present invention;
Figure 2 is a perspective sectional view of the PC column in Figure 1, Figure 3 is a plan sectional view showing another embodiment, Figure 4 is a diagram for explaining an example of construction, and Figure 5 is another example of construction. A diagram for explaining an example, FIG. 6 is a diagram for explaining construction of a PC column using a conventional mechanical joint. 1...PC column 2...Outer shell formwork 3...Sheath 4...
Concrete 5... Column main reinforcement patent applicant Obayashi Co., Ltd. General Representative Patent attorney - Ken Iro Axis
Patent Attorney Masatoshi Matsumoto Figure 1 Figure 4 Figure 5

Claims (2)

[Claims] (1) In a precast concrete column that is centrifugally formed, sheaths for inserting column main reinforcement into the outer shell form are arranged at intervals in the circumferential direction and penetrated in the longitudinal direction, and the outer shell form A precast concrete column characterized by being formed by centrifugally forming the frame by pouring concrete into it while rotating the frame. (2) The precast concrete column according to claim 1, wherein the outer shell formwork is made of steel.