JPH0771072A - Precast concrete form-covered column and execution therefor - Google Patents

Abstract

PURPOSE:To obtain a precast concrete form-covered column having high operating efficiency. CONSTITUTION:Main reinforcements 2... of columns built on a working floor, cylindrical precast concrete forms 3 disposed around the main reinforcements 2... of columns and concrete C placed into the precast concrete forms 3 are provided. These main reinforcements 2... of columns, precast concrete forms 3 and placed concrete C are unified and constructed, and hoops 4..., 6... are arranged into the sidewall of the precast concrete forms 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a column in a building structure, and more particularly to a precast form covered column constructed by using a precast concrete formwork prepared in advance and a method for constructing the column.

[0002]

2. Description of the Related Art As is well known, in the construction of building structures, due to a shortage of workers in recent years, the construction period is lengthened due to the work of assembling and dismantling a weir board form, and the amount of weir board used is reduced. In consideration of environmental issues and the like, various types of precast concrete formwork (hereinafter simply referred to as “PC formwork”) are used when constructing the skeleton and the like.

For example, when constructing a pillar using this PC formwork, the following steps have been taken. (A) A required column main bar is erected at a predetermined column construction position on the work floor, and the bar reinforcement is tied to this column main bar to reinforce and assemble the column rebar. (B) A cylindrical PC form having a length of one floor is prepared, and it is erected from above so as to include the pillar rebar and fixed at a predetermined position. (C) In order to restrain the deformation of the side wall of the PC form due to the concrete pouring pressure, holes are provided in advance in the side walls of the PC form facing each other to prevent the deformation of the conventional weir plate form such as separators and pecon. Or use the jig
On the outside of the side wall of the PC form, measures such as attaching column clamps at predetermined intervals in the vertical direction are taken, and then concrete is placed in the PC form.

[0004]

By the way, the tying work of the stirrups to the column main bars in the above step a is performed manually by a reinforcing bar worker while tying them one by one with a tying wire. Therefore, the work schedule had to be devoted to the work, which significantly reduced the work efficiency at the work site. Further, with respect to the deformation restraining means for the side wall of the PC form in the above step C, it takes a lot of time to install and remove the means, and the work efficiency at the work site is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a precast concrete formwork covered column with high work efficiency and a method for constructing the same.

[0006]

According to a first aspect of the present invention, there is provided a column main bar built on a work floor, a cylindrical precast concrete formwork arranged around the column main bar, and the precast. It is configured to have a concrete cast in a concrete formwork, and these column main bars, precast concrete formwork, and cast concrete are integrally constructed, and the inside of the side wall of the precast concrete formwork is described above. It is characterized in that a stirrup for the main column bar is provided.

According to a second aspect of the present invention, a tubular precast concrete formwork formed by arranging stirrups inside the side wall is prepared, and a column main bar is installed at a predetermined position on the work floor. The precast concrete formwork is arranged around the main pillars of the column, concrete is placed in the precast concrete formwork, and a column in which these main pillars of the precast concrete formwork and the placed concrete are integrated The feature is that it was constructed.

[0008]

According to the first aspect of the present invention, a column main bar built on the work floor and a cylinder arranged around the column main bar, and the stirrups for the column main bar arranged inside the side wall thereof. -Shaped precast concrete formwork and the concrete that has been cast and hardened in the precast concrete formwork are integrated, and the shearing force acting on the precast concrete formwork-covered column is applied around the column main bar. It is transferred to the stirrup through the hardened concrete that has been set and is processed.

According to the second aspect of the present invention, a precast concrete formwork is provided around the pillar main bar built on the work floor, and inside the side wall of the column main bar, pre-cast concrete formwork is preliminarily provided with the stirrups for the column main bar. By placing concrete in the precast concrete formwork and hardening it, a precast concrete formwork-covered column in which the main bar of the column, the precast concrete formwork, and the hardened concrete are integrated is constructed.

[0010]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of a precast concrete formwork-covered column according to the present invention.
In the figure, reference numeral 1 indicates a precast concrete formwork-covered column.

As shown in FIG. 1, a precast concrete formwork-covered column 1 is a column main bar 2 which is built on a working floor so as to define a substantially square shape in plan view at a predetermined interval.
A cylindrical precast concrete formwork (hereinafter referred to as "PC formwork") 3 arranged around these pillar main bars 2 ...
The concrete structure has a concrete C that has been cast into the PC form 3 and hardened.
The formwork 3 and the concrete C are integrated into a column as a so-called structural body.

The PC mold 3 is a tubular molded body which is manufactured by a well-known centrifugal molding method of concrete and has a substantially square cross-section with a substantially constant thickness as a whole with the inside thereof being a concrete placing space. , The length of one side is set equal to the length of one side of the pillar to be constructed. Further, the four corners of the inner peripheral surface of the PC form 3 are formed into an arc-shaped so-called R surface having a predetermined curvature.

The wall thickness of each side wall of the PC form 3 is set to be 3 to 6% of the width of the precast concrete form covering column 1 to be constructed, that is, the outer side dimension of the PC form 3. Here, the outer side dimension W is 1000 mm, and the thickness of each side is 40 mm (4% of the outer side dimension W). A thick portion is formed at the center of each side wall of the PC mold 3, and the width of the thick portion is 12 to 25% of the outer dimension W of the PC mold 3. Further, the thickness of the thick portion is set to be 120 to 150% of the above thickness. The thick portion reinforces each thin side wall, and when the width and the thickness of the thick portion are smaller than the above-mentioned set values, there is a possibility that the reinforcing effect by the thick portion cannot be expected. , PC formwork 3
This is because it is difficult to fill the material when manufacturing the. On the other hand, if the width and the wall thickness exceed the above-mentioned set values, the reinforcing portion has an unnecessarily large size, and the weight of the PC form 3 becomes difficult to handle.

Further, inside the side wall of the PC form 3, when the pillar is formed by the PC form 3, the stirrups 4 ... Are arranged with respect to the column main bars 2. The straps 4 are embedded in a state in which they are joined at a predetermined interval in the longitudinal direction of the longitudinal strips 5 arranged inside. Here, the deformed bar (D10) is adopted for the stirrups 4 ...
The cover thickness is about 30 mm from the outer peripheral surface of the PC mold 3.
Is set to be

On each of these stirrups 4 ... Two sub stirrups (stirrups) 5 ... The side portions are located on the stirrups 4, and the long side portions are arranged in the shape of a double girder in a plan view, and are arranged so as to surround the main reinforcing bars 2a of the built-in pillar main reinforcing bars 2 ... Has been done. Here, each of the sub-bands 5 has the PC form 3 at both ends thereof.
Is bent and arranged so as to be located in the thick portion in the center of the side wall of the. Further, various hooks can be applied to the bending process of this end portion.

The concrete composition of the PC mold 1 may be a mortar composition depending on the shape and application of the molded product. As the cement to be used, various kinds of cement such as ordinary Portland cement and blast furnace cement can be used, and as the aggregate, not only natural aggregate but also artificial aggregate can be used.

Next, a method of constructing the precast concrete formwork-covered column 1 will be described. First of all, a cylindrical PC form 3 is prepared in advance by arranging the stirrups 4 ... Inside the side wall in a factory or on site, and placed on a temporary storage site such as a stockyard in the work site. deep. on the other hand,
Pillar main reinforcements 2 ... are erected at a predetermined position on the work floor in the work site, a required number of pillars to be constructed, and at predetermined positions. Then, after the PC formwork 3 is lifted by a lifting machine such as a crane and carried in above the built-in pillar main bars 2 ..., the PC mainframe 2 is inserted and arranged around the pillar main bars 2 ... Set up. Furthermore, after positioning and fixing the PC formwork 3 at a predetermined installation position, concrete C is placed in the PC formwork 3, and the pillar main bars 2, ..., PC formwork 3, and the placed concrete C are Build a solid, solid pillar.

In the precast concrete formwork-covered column 1 having the above-mentioned structure, since the strips 4 for the column main bars 2 are arranged inside the side wall of the PC form 3, when the column is subjected to a shearing force. , The inside of the PC form 3, and the stirrups 4 through the hardened concrete C around the pillar main bars 2 ...
It is transmitted to ... and processed. Further, the sub-strands 5 arranged on the stirrups 4 ... Constrain the deformation of the side wall portion of the PC form due to the concrete pouring pressure.

As described above, the precast concrete formwork-covered column 1 of the above-described embodiment has the column main bar 2 arranged in the column.
Since the stirrups 4 for ... are arranged inside the side wall,
The PC form 3 can be constructed by a relatively simple process of arranging and fixing the PC form 3 so as to enclose the pillar main bars 2 ..., Placing concrete C therein and hardening it. Therefore, it is not necessary to perform the conventional work of binding the stirrups to the main pillars, and the work efficiency on site can be greatly improved.

Further, the deformation of the side wall portion of the PC form 3 due to the placing pressure of the concrete C is restrained by the stirrups 4 and the sub stirrups 6 disposed inside the side wall of the PC form 3, and It is not necessary to take a means for restraining the deformation from the outside, and a highly accurate column can be efficiently constructed. Moreover, since the shear strength of the PC mold 3 itself is increased, it is easier to handle during transportation than in the conventional case.

Further, a thick-walled portion projecting inward is formed at the center of each side of the PC form 3, whereby each thin side is effectively reinforced and the strength of the PC form 3 is increased. In addition to being able to secure enough, since the thick part is located in the central part of each piece, in combination with the above-mentioned stirrups 4, ...
When concrete C is placed on the PC form 3, P
It is possible to effectively prevent the side wall portion of the C frame 3 from being deformed.

In addition, each corner of the inner peripheral surface of the PC form 3 is rounded.
Since it is formed on the surface, when the concrete C is cast inside the PC form 3 to construct the precast covered column 1, the concrete C is completely filled up to this corner. 3 It is necessary to reliably prevent the formation of voids between the concrete and the cast concrete C, and to prevent the harmful effects of the presence of voids, such as cracking of the column body during an earthquake. You can Furthermore, P
Since the outer peripheral surface of the C form 3 becomes the surface of the pillar to be constructed, this surface can be used as it is as a finishing base surface, and it has high strength and durability even as an exposed finish surface. Needless to say, the drawbacks of cast-in-place reinforced concrete columns can be eliminated in the same way as the construction method using.

Further, in the precast concrete formwork-covered column 1 of the above-mentioned embodiment, since the PC formwork 3 is thin and extremely lightweight, handling such as transportation or assembling work at the site when constructing the column is extremely difficult. Light and
It goes without saying that work efficiency can be improved.

FIG. 2 shows a second embodiment of the precast concrete formwork-covered column according to the present invention. In the second embodiment, instead of the secondary stirrups 6 ... in the first embodiment shown in FIG. 1, it is bent into a substantially 8-shaped shape in a plan view intersecting at substantially the center of the PC form 3. Viceps 6 ...
Are arranged so as to surround the central main bar 2a of the column main bar 2, ... In this case, the same action and effect as those of the first embodiment can be obtained.

FIG. 3 shows a third embodiment of the precast concrete formwork covering column according to the present invention. In the third embodiment, the sub-belt 6 in the first embodiment is ...
Instead of, the sub-belt 6 bent into a diamond in plan view ...
However, the corners thereof are located on the reinforcing bars and are arranged so as to surround the central main bars 2a ... Of the column main bars 2. In this case, in addition to the same effects and advantages as those of the first embodiment, a large space is provided in the center of the PC form 3, so that not only reinforced concrete columns but also steel reinforced concrete columns can be used. Applicable.

FIG. 4 shows a fourth embodiment of the precast concrete formwork covering column according to the present invention. In the fourth embodiment, in place of the sub-reinforcing bars 6 ... In the first embodiment, rod-like sub-reinforcing bars 6 ... Are erected at the central portions of the opposing side portions of the reinforcing bars 4. Also in this case, the same action and effect as those of the first embodiment can be obtained.

FIG. 5 shows a precast concrete formwork-covered column according to a fifth embodiment of the present invention. In the fifth embodiment, the bar-shaped sub-belt 6 in the fourth embodiment is used.
Is constructed so as to be erected in a state of being rotated by a predetermined angle in a horizontal plane, and in this case as well, the same action and effect as those of the first embodiment can be obtained.

In each of the above embodiments, the stirrup 4 is used.
... was embedded inside the side wall of the PC form 3,
The reinforcing bars 4 may be arranged so as to be partially exposed from the inner peripheral surface of the side wall of the C-frame 3, and in this case also, the same actions and effects as those of the above-described embodiments can be obtained. .

Further, although different diameter reinforcing bars (D10) were used for the stirrups 4, ... And the sub stirrups 6 ,.
It is needless to say that the reinforcing bar used can be changed to another standard according to the thickness of the PC form 3, and the covering thickness can be set appropriately according to the reinforcing bar used.

Further, the stirrups 4 ... and the sub stirrups 6 ...
The deformed rebar is not limited to the above-mentioned deformed rebar, and carbon fiber, aramid fiber, or the like coated with a resin and molded into a predetermined shape like the above rebar may be used.

Further, in order to give the precast concrete formwork-covered column 1 to be constructed a predetermined degree of structural strength, it can be reinforced and strengthened by the following reinforcing and strengthening means.

As the first reinforcing and strengthening means, the PC form 3
It is to use high-strength concrete or fiber reinforced concrete (hereinafter referred to as “FRC”) for the concrete C to be placed inside. Here, high-strength concrete means
Normally, the design standard strength is concrete with a strength of 270 kg / cm2 or more. This strength is achieved by improving the strength of the binder, using high quality aggregate, and improving the adhesion between the aggregate and the binder. It is concrete with admixtures such as additives and admixtures such as silica fume and fly ash. Further, FRC is concrete whose strength is increased by mixing reinforcing fibers such as steel fibers, carbon fibers, and aramid fibers into the concrete.

As the second reinforcing and strengthening means, the column main bars 2 ...
Is to increase the amount of muscle arrangement. The increase in the bar arrangement amount is achieved by increasing the number of bar arrangements of the column main bars 2 ... Or by setting the diameter thereof large. When the diameters of the column main bars 2 are set to be large, the diameters of all the column main bars 2 may be set to be large, or the diameters of the column main bars 2b located at the four corners of the column may be set to be large.

As the third reinforcing and strengthening means, PC is used.
The purpose is to increase the strength of the mold 3. In this case, the PC
By mixing the concrete composition of the mold 3 with an admixture such as a high-performance damping material, an admixture such as silica fume or fly ash, or a reinforcing fiber such as steel fiber, carbon fiber or aramid fiber, or in combination. is there.

By reinforcing and strengthening by each of these means, the shear strength of the column to be constructed can be increased,
It is possible to form a pillar having higher rigidity and proof strength than conventional ones. In particular, when the strength of the PC form 3 is increased, the stirrups are restrained by mortar or concrete having high compressive strength and bending strength, and the shearing / bending strength of the column to be constructed is effectively increased. be able to. In addition,
It goes without saying that the columns can be more effectively reinforced and strengthened by combining the first to third reinforcing and strengthening means.

Further, spiral welded cage bars and expanded metal for preventing cracks can be embedded in the side wall of the PC form 3. In the case of a spiral welded cage bar, the same action and effect can be obtained by arranging the sub-reinforcing bar 6 in accordance with the shape of the spiral welded cage, and in the case of using expanded metal, , As shown in FIG.
In addition to the above-described actions and effects, a high crack preventing effect can be obtained by arranging the structure on the outside of the stirrups 4 ... along the side wall of the C-frame.

[0037]

EFFECTS OF THE INVENTION According to the precast concrete formwork-covered column and its construction method according to the present invention, the following effects can be obtained. In the precast concrete formwork-covered column according to claim 1, a tubular precast concrete formwork in which a band is arranged inside the side wall is arranged around the column main bar to be positioned and fixed, and concrete is cast inside the column. Since it is constructed by setting and hardening it, there is no need for the work of binding the stirrups to the main pillars of the columns, and the construction efficiency can be greatly increased compared to the conventional case.

According to the method for constructing a precast concrete formwork-covered column according to claim 2, a tubular precast concrete formwork in which a band is preliminarily disposed inside the side wall is disposed around the main pillar of the column for positioning and fixing. However, since the pillar is constructed only by placing concrete in the precast concrete formwork, it is possible to significantly increase the construction efficiency as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a plan sectional view of an essential part showing a first embodiment of a precast concrete formwork-covered column according to the present invention.

FIG. 2 is a plan sectional view showing a second embodiment of a precast concrete formwork-covered column according to the present invention.

FIG. 3 is a plan sectional view showing a third embodiment of the precast concrete formwork-covered column according to the present invention.

FIG. 4 is a plan sectional view showing a fourth embodiment of the precast concrete formwork-covered column according to the present invention.

FIG. 5 is a plan sectional view showing a fifth embodiment of the precast concrete formwork-covered column according to the present invention.

FIG. 6 is a plan sectional view showing a sixth embodiment of the precast concrete formwork-covered column according to the present invention.

[Explanation of symbols]

 1 Precast concrete formwork covered columns 2 ... Column main bar 3 Precast concrete formwork 4 ..., 6 ... Reinforcing bar C concrete

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideo Tsukagoshi 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Yuro Baba 4-30-5 Ryogoku, Sumida-ku, Tokyo Teihu Incorporated (72) Inventor Shigeharu Murayama 4-30-5 Ryogoku, Sumida-ku, Tokyo Teihu Co., Ltd. (72) Inventor Yasuki Shiobara 4-30-5 Ryogoku, Sumida-ku, Tokyo Teihu Co., Ltd.

Claims (2)

[Claims] 1. A column main bar built on a work floor, a cylindrical precast concrete formwork arranged around the column main bar, and concrete cast in the precast concrete formwork. The column main bar, the precast concrete formwork, and the cast concrete are integrally constructed, and the tie bar for the column main bar is arranged inside the side wall of the precast concrete formwork. Characteristic precast concrete formwork covered columns. 2. A cylindrical precast concrete formwork formed by arranging strips inside the side wall is prepared, a column main rebar is built at a predetermined position on the work floor, and the precast is placed around the column main rebar. A concrete formwork was arranged, concrete was placed in the precast concrete formwork, and a pillar was constructed in which these column main bars, the precast concrete formwork, and the placed concrete were integrated. A method of constructing precast concrete formwork covered columns.