JP3208691B2 - Precast concrete covered column and its construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precast concrete-covered column formed by using a precast concrete formwork in which a reinforcing bar is embedded in a cylindrical concrete, and a method of applying the same.

[0002]

2. Description of the Related Art Conventionally, for the purpose of improving work efficiency, a precast concrete formwork (fume box) in which a reinforcing bar is embedded in a cylindrical concrete is previously formed in a factory or the like by a well-known centrifugal molding method. The method of applying the so-called half-precast method to pillars is to manufacture the precast concrete formwork as a formwork, install it at a predetermined position on the building site, and cast in-place concrete into the inside of it and make it a pillar. Has been adopted. In the above construction method, when the earthquake-resistant wall is cast on the side of the precast concrete formwork, a precast concrete formwork with no side opening is installed, and a predetermined side of the precast concrete formwork is provided. A hole is made, and a horizontal streak for the wall is inserted from this hole to fix and arrange the streaks. In this state, cast-in-place concrete is cast inside the precast concrete formwork, and after the cast-in-place concrete has hardened, it is reinforced by removing the wall-placed place on the side of the precast concrete formwork. After forming the slit part where the streak was exposed, this slit part was connected to the horizontal streak as a joint surface and the wall part was arranged, and concrete was poured after assembling the wall formwork I have. However, the precast concrete formwork has a problem that the precast concrete formwork other than the slit may cause cracks in the hanging operation. For this reason, a method of forming a precast concrete-covered column by adopting a precast concrete formwork that has been formed in advance at the time of molding at a factory or the like by forming a slit portion where a reinforcing bar is exposed at a wall joint portion of the side portion. It is being adopted.

[0003]

When a precast concrete covered column is formed by using a precast concrete formwork in which a slit portion is formed in advance as described above, the strength of the precast concrete covered column is increased because the slit portion is formed only of reinforcing bars. The concrete cast in the precast concrete formwork leaks out of the slits, and only the pillars can be cast prior to the wall, because the concrete will be deformed and destroyed due to lack of There was a problem that it was not possible.

Accordingly, an object of the present invention is to provide a precast concrete in which the strength is not insufficient even if the slit portion is formed in advance, and the concrete poured into the inside of the precast concrete form does not leak. An object of the present invention is to provide a precast concrete-covered column using a formwork frame and a method for constructing the column.

[0005]

In order to achieve the above object, a precast concrete-covered pillar of the present invention has a reinforcing bar embedded in a cylindrical concrete, and the reinforcing bar is exposed on a side surface. Precast concrete formwork in which a slit portion for wall joining is formed, provided inside the precast concrete formwork, a column main body having column reinforcing steel and concrete, and a part from the slit portion is A lateral bar buried in the column body and projecting outward so that the other part is buried in the wall, and the precast concrete formwork is at least between the concrete on both sides of the slit portion and the reinforcing bar. It is characterized in that a shape retaining bar and a reticulated form are separately provided.

Further, in the method for constructing a precast concrete-covered column according to the present invention, a reinforcing bar is embedded in the inside of a cylindrical concrete, and a slit portion for joining a wall having the reinforcing bar is exposed on a side surface. Prepare a precast concrete formwork provided with at least the reinforcing bars between the concrete on both sides of the slit portion apart from the reinforcing bars, and a precast concrete formwork is provided, and column reinforcing bars are erected and arranged, The precast concrete formwork is suspended and positioned while the column rebar is inserted inside, and a part of the horizontal streak is inserted from the slit part of the precast concrete formwork and the other part is projected outward. Concrete is poured into the inside of the precast concrete formwork.

[0007]

According to the precast concrete-covered pillar and the method for constructing the same according to the present invention, the precast concrete formwork is reinforced between the concrete on both sides of the slit portion formed on the side surface thereof and having the reinforcing bars exposed. Since the shape-retaining bars and the reticulated formwork are provided separately from the rebars, the strength of the slit portion is improved by the reshaped-reinforcing bars, and the reticulated formwork is cast into the precast concrete formwork. Therefore, the strength of the precast concrete-covered column as a whole is improved, and the precast concrete-covered column can be pre-constructed prior to the concrete construction of the wall.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A precast concrete-coated column according to a first embodiment of the present invention will be described below with reference to the drawings. First
As shown in FIG. 1, the precast concrete-covered pillar of the embodiment has a rectangular cylindrical shape having four side surfaces 1 </ b> A to 1 </ b> D having a predetermined thickness so that the outer portion thereof has a substantially square shape in plan view. Formwork (hereinafter referred to as
A precast member) 1 and the precast member 1
Column cast-in-place concrete 2 cast inside the column and column reinforcing steel 3 buried in the column cast-in-place concrete 2
And a horizontal streak 5 partially embedded in the pillar body 4.

The column reinforcing bar 3 of the column main body 4 includes a plurality of column main reinforcing bars 7 extending in the longitudinal direction of the precast member 1 and a plurality of column reinforcing bars 8 wound around the column main reinforcing bars 7. The pillar main reinforcement 7 has a substantially square shape in plan view slightly smaller than the precast member 1 and has a mutual distance such that a distance between adjacent ones of the side portions 1A to 1D of the precast member 1 is substantially equal. Are arranged at predetermined intervals. The column stirrups 8 are arranged at a predetermined pitch in the vertical direction so as to extend along the horizontal direction.

As shown in FIG. 2 and FIG. 3, the precast member 1 is such that each of the side portions 1A to 1D has a central thick portion 13 and thinner portions 12 on both sides of the thick portion 13 which are thinner. , 12. Here, the central thick part 1
Reference numeral 3 is formed for the purpose of obtaining sufficient strength against an impact load from the outside during handling of the precast member 1 and a pressure at the time of placing concrete in the column.

The precast member 1 is made of reinforced concrete formed by centrifugal concrete molding. A reinforcing bar, a shape-retaining bar, or the like is provided at any one of the side portions 1A to 1D, which is to be joined to a wall (not shown). Is formed continuously over the entire range in the length direction. In the first embodiment, the slit portion 14 is formed in the thin portion 12 on the side portion 1D side of the side portion 1A.
A is provided. Here, of the side surface portions 1A to 1D, the inner surface side of each corner portion formed by the boundary portion between adjacent ones is formed as a curved surface, that is, an R surface, and the outer surface side of each corner portion is formed in a planar shape. It has a chamfered shape.
Of course, the inner surface of each corner may be flat, or the outer surface may be R.
Surfaces are also possible.

As shown in FIG. 2 to FIG. 4, a part of the reinforcing bar buried in the concrete 17 has a square cylindrical shape similar to the precast member 1 as shown in the slit portion 14A. A square ring-shaped closed reinforcing bar (a reinforcing bar) made of a grid-like reinforcing bar 15 having a small gap between the left and right sides and a deformed reinforcing bar having a larger diameter than the reinforcing bar 15 and arranged outside the reinforcing bar 15. 16). Here, the reinforcing bars 15 are used to improve the strength of the entire precast member 1, and the reinforcing bars 16 are used.
As described later, reinforcing reinforcement is provided to maintain the shape of the precast member 1 while maintaining the interval between the slit portions 14A. The reinforcing bars 15 are provided inside the entire length of the precast member 1, and the shape-retaining stirrups 16 are arranged along the horizontal direction, respectively.
Are arranged at a predetermined pitch in the length direction. The shape-retaining stirrups 16 are provided near the upper end and the lower end where the strength is required most, with a large amount of reinforcement.

Here, in the first embodiment, as the mesh form K, a cut-out spread metal mesh such as an expanded metal or a metal lath made by cutting a thin steel plate or the like at regular intervals by punching it and stretching it to form a mesh. After being cut into the shape of the slit portion 14A, the pre-cast member 1 is molded and attached to the inner surface of the slit portion 14A with an iron wire or the like. Further, in the first embodiment, the mesh openings of the reticulated formwork K are sized so as not to allow the column cast-in-place concrete 2 to pass through.

Although not shown, the precast member 1 has, for example, an outer mold having an inner shape substantially the same as the outer shape of the precast member 1, and an outer shape having the same shape as the inner shape of the precast member 1. In a state in which the reinforcing bars 15 and the shape-retaining stirrups 16 are arranged in the space formed by the inner mold having the inner mold, the space 17 is filled with concrete 17 and centrifugally molded to be manufactured at a factory or the like. It has become. The outer mold for centrifugal molding has an outer mold projecting portion projecting inward at a portion corresponding to the slit portion 14A and formed continuously in the longitudinal direction of the precast member 1. In addition, an inner mold projecting portion projecting outward at a portion corresponding to the slit portion 4A is formed continuously in the length direction of the precast member 1. The protruding end surfaces of the outer and inner frame protrusions are fitted together while holding the reinforcing bars 15 and the shape-retaining band bars 16 therebetween. The concrete 17 is prevented from entering the inside, and a slit portion 14A composed of a reinforcing bar, that is, a reinforcing bar 15 and a shape-retaining bar 16 is provided.
However, concrete 1
7 will be formed in advance at the time of curing. In addition,
The slit portion 14A has, for example, a reinforcing bar 15 and a shape-retaining band bar 16 interposed in the outer mold frame and the inner mold frame which do not have the above-mentioned projecting portion so that the concrete 17 does not enter the formation position of the slit portion 14A. A core may be provided, and the core may be removed after the concrete 17 has hardened.

Hereinafter, an example of a method of constructing the precast concrete-covered column having such a configuration will be described. First, as shown in FIG. 5, a column reinforcing bar 3 composed of a column main bar 7 and a column bar bar 8 is assembled at a column construction position on a foundation slab 18, and thereafter, a slit portion 14A is previously formed in a manufacturing factory. The precast member 1 is transported to a construction site, and as shown in FIG. 6, the precast member 1 is hung so that the column reinforcing bar 3 is inserted into the inside thereof. Then
As shown in FIG. 7, using the adjusting member 19 such as a steel rod with a turnbuckle, the adjustment of the built-in precast member 1 such as positioning is performed. And the slit part 1
4A, a plurality of horizontal streaks 5 are inserted into one end of the precast member 1 with a predetermined fixing length and the other end is projected outward (see FIG. 1). And
In this state, the cast-in-place concrete 2 is cast inside the precast member 1.

Here, the cast-in-place concrete 2 is divided into a plurality of times and the upper concrete is poured after the previously set concrete is hardened, whereby the mesh opening of the mesh form K of the slit portion 14A is opened. The amount of concrete leaking from the concrete may be adjusted to prevent unnecessary leakage. In addition, by casting the column-part cast-in-place concrete 2 a plurality of times in this way, it is possible to prevent the precast member 1 from being applied with excessive concrete pressure.

As described above, the mesh openings of the mesh form K are
Since the size of the pillar portion cast-in-place concrete 2 is not allowed to pass, the concrete engages with and closes the opening of the mesh form K to prevent the concrete 2 from leaking. Further, by the engagement of the concrete in this manner, the outer surface of the reticulated formwork K, that is, the joint surface of the cast-in-place concrete for a wall, which will be described later, has an uneven shape, so that the joint effect can be favorably obtained.

After the cast-in-place concrete 2 is hardened, although not shown, the reinforcement of the wall is connected to the horizontal reinforcement 5 for construction, and a pair of precast wall form members or molds for forming the wall is formed. A frame weir plate is provided in contact with the precast member 1 so as to be opposed to each other in a state where it is aligned with the slit portion 14A. Is formed to form a wall portion.
It should be noted that cast-in-place concrete for a wall is poured into the horizontal streaks 5 with the wall streaks tied appropriately.

According to the precast concrete-covered column of the first embodiment constructed by such a method, the precast member 1 has a slit portion 14A on the side surface portion 1A corresponding to the position where the wall portion is driven. Since the concrete 17 is formed in advance at the time of hardening of the concrete 17, that is, at the time of manufacturing in a factory, it is not necessary to perform hanging afterward, so that the occurrence of cracks and the occurrence of shavings of the precast member 1 can be prevented. In addition, between the concrete 17 on both sides of the slit portion 14A, apart from the reinforcing bar 15, the shape-retaining band 16
Is provided, the strength is improved by the shape-retaining straps 16. Therefore, breakage or the like due to a decrease in the strength of the slit portion 14A does not occur, and the strength of the entire precast concrete-covered column is improved. In addition, since the mesh portion K is provided in the slit portion 14A, it is possible to perform the preceding construction prior to the wall portion concrete of the cast-in-place concrete of the pillar portion, and the drainage of the cast-in-place concrete portion 2 is good from the slit portion 14A. Will be performed.

The above construction method is an example, and various other construction methods can be applied.

For example, before the cast-in-place concrete 2 is cast, a metal plate or the like fitted to the slit portion 14A is provided inside the reinforcing bar 15 and the shape-retaining bar 16 of the slit portion 14A at the construction site at the construction site. A metal lath or the like may be attached to provide a mesh form K for stopping concrete, and the cast-in-place concrete 2 may be continuously or intermittently cast.

Further, after inserting the horizontal streak 5 into the inside of the precast member 1 from the slit portion 14A by a predetermined fixing length, etc., before the cast-in-place concrete 2 is cast, the reinforcing steel for the wall portion and the precast wall mold are formed. A frame member or a wall form is connected to the precast member 1 so as to be aligned with the slit portion 14A, and further, a form reinforcing bar such as a beam or a slab is constructed. It is also possible to pre-cast the column cast-in-place concrete 2 into the precast member 1 and then cast the wall cast-in-place concrete. In this case, a concrete with a predetermined slump and strength as structural concrete is adopted as the cast-in-place concrete, and a large slump concrete with higher fluidity is adopted as the cast-in-place concrete for the wall. In this way, by allowing the cast-in-place concrete to be placed later and allowing the large-slump concrete to be cast, it is possible to prevent the occurrence of cavities (junkers) in the concrete in the thin-walled formwork.

The precast concrete-covered columns can be changed to various shapes without being limited to the above. For example, it is also possible to use what binds an L-shaped muscle as the shape-retaining stoma. Further, as shown in FIG. 9, it is also possible to provide the shape-retaining streaks 16 inside the reinforcing bars 15, and by arranging in this manner, the unevenness on the surface side is eliminated and the reinforcing bars 15 are evenly disposed on the outer surface side. Since it is provided and molded, it is possible to further prevent cracks generated on the surface of the precast member 1 due to a load at the time of placing concrete. Further, like the precast member 21 of the second embodiment shown in FIG. 10, two slit portions 22 are provided on the side portions 21A and 21C.
A, 22C, and the side portions 25A, 25B, 25 like the precast member 25 of the third embodiment shown in FIG.
Of course, it is also possible to provide three slits 26A, 26B, 26C in C.

Further, the precast members 1, 2, 21
In order to further increase the rigidity of the column with the wall using 5, it is possible to reduce the arrangement pitch of the shape-retaining stirrup 16.
In addition, the slits 14A, 22A, 22C, 26A-2
It is possible to provide the 6C not continuously in the vertical direction but intermittently at regular intervals as a horizontal connecting portion of concrete, but it is more advantageous to provide the 6C continuously in terms of cost. Also preferred. Also, as described above, the casting of cast-in-place concrete is performed in several steps,
By lowering the casting speed, the lath, that is, the slit portion 14A,
22A, 22C and 26A-26C, the precast members 1 and 2 are used.
The generation of cracks of 1, 25 can be effectively reduced. Also, the precast members 1 and 2 by the separator
It is possible to reinforce the precast members 1, 25, but it is preferable not to use them because the precast members 1, 25 may be perforated to cause unexpected cracks.

Further, in the above, the mesh form K is formed by cutting a thin steel plate or the like at predetermined intervals by punching, expanding the mesh, and expanding the mesh into a punched expanded metal mesh such as expanded metal or a metal lath. However, it is also possible to adopt a welded mesh, that is, a welded wire mesh, in which iron wires or the like are assembled in a grid shape and the contacts are electrically welded into a net shape. Also in this case, it is preferable that the mesh opening has a size that does not allow the cast-in-place concrete to pass through.

In the case where the reinforcing bars 5 formed by meshing iron wires or the like in a grid shape and electrically welding the contacts to form a mesh are formed into a rectangular tube shape, a plurality of vertical bars are arranged at positions that form a rectangular shape in plan view. A plurality of rectangular ring-shaped stirrups are weld-fixed up and down at the specified pitch on the outer periphery of the vertical streak, or spiral spirals are wound around the perimeter of the above-mentioned streaks spirally so that the position is gradually shifted up and down and weld-fixed May be. Furthermore, the arrangement pitch of the stirrups of the reinforcement 5 or the winding pitch of the spiral reinforcer is to make the pitch of the lower part smaller than that of the upper part or to make the lower part folded back at the lower end so as to be doubled. For example, it is possible to increase the strength of the lower portion where a large pressure is generated when the cast-in-place concrete is cast inside. Further, it is also possible to provide auxiliary muscles in parallel with the vertical stripes in proximity to those located at the four corners of the vertical stripes. In addition, since the reinforcing bar 15 is likely to receive an impact on the upper and lower ends when handling itself, the upper and lower ends can be double-folded to reinforce this portion.

In the above description, a square ring made of deformed reinforcing bars or the like is provided as an example of a shape-retaining bar provided over the entire circumference of the reinforcing bar 15, but the positional relationship of the slit portions and the like is maintained. If the main purpose is to do so, at least one of the inside and outside at least between the concrete on both sides of the slit portion where the reinforcing bars are exposed, the shape retaining bars may be provided, The shape retainer can be variously changed according to the position of the slit portion and the like.

For example, like the precast member 27 of the fourth embodiment shown in FIG. 12, slit portions 28B and 28D are formed in the thin portion 12 on the side surface 27C side of the side surface 27B and the side surface 27D opposed thereto. When provided, it extends from approximately the center of the thin portion 12 on the side surface portion 27B side of the side surface portion 27A to approximately the center of the thin portion 12 on the side surface portion 27D side of the side surface portion 27A, passing through the side surface portions 27B, 27C, and 27D. As shown in FIG.
The shape-retaining streaks 30B extending from substantially the center of the thin portion 12 on the side portion 27A side of the side portion 27B to the side portion 27B side of the thick portion 13 of the side portion 27C, and another side portion 2 of the side portion 27D
A shape-retaining line 30D extending from substantially the center of the thin portion 12 on the 7A side to the side surface portion 27D of the thick portion 13 of the side surface portion 27C, or a square ring-shaped closed shape as shown in FIG. The shape streaks 31 can also be used.

Further, as in the precast member 32 of the fifth embodiment shown in FIG. 15, a slit portion 33A is formed in the thin portion 12 on the side surface portion 32B side of the side surface portion 32A, and a thin portion on the side surface portion 32C side of the side surface portion 32D. 12 is provided with a slit portion 33D, the thick portion 13 of the side surface portion 32B is provided.
16. A shape-retaining streak 34 extending from the side surface portion 32A side to the side surface portion 32D side of the thick portion 13 of the side surface portion 32C passing through the side surface portions 32A and 32D, or as shown in FIG.
35A extending from the side portion 32A side of the thick portion 13 to the position beyond the thick portion 13 of the side portion 32A, and another side portion 32D of the thick portion 13 of the side portion 32C.
It is also possible to use a shape-retaining line 35D extending from the side to a position beyond the thick portion 13 of the side surface portion 32D. Similarly to the above, as shown in FIG. It is also possible to use

Further, as in the precast member 38 of the sixth embodiment shown in FIG. 18, a slit portion 39A is formed in the thick portion 13 of the side portion 38A, and a slit portion is formed in the thick portion 13 of the side portion 38C opposed thereto. In the case where 39C is provided, the shape-retaining streaks 40A extending from the side surface portion 38A side of the thick portion 13 of the side surface portion 38B to the side surface portion 38A side of the thick portion 13 of the side surface portion 38D when the respective side surfaces 38B are provided. And a separate shape retaining bar 40C extending from the side surface portion 38C of the thick portion 13 of the side surface portion 38B to the side surface portion 38C side of the thick portion 13 of the side surface portion 38D, FIG.
As shown in FIG. 3, a shape-retaining streak 41A extending from substantially the center of the thin portion 12 on the side surface 38A side of the side surface portion 38B and extending to substantially the center of the thin portion 12 on the side surface portion 38A side of the side surface portion 38D, and The other side portion 3 of the side portion 38B
A shape-retaining streak 41C extending from substantially the center of the thin portion 12 on the 8C side to substantially the center of the thin portion 12 on the side surface 38C side of the side portion 38D through the side surface portion 38C, or as shown in FIG. It is also possible to form the shape-retaining line 42 closed in a square ring shape.

In addition, the shape-retaining muscle may be constituted by a spiral muscle spirally wound around the reinforcing muscle so as to gradually shift its position up and down. In addition, it is also possible to partially reduce the arrangement pitch and increase the diameter of only the portion requiring high strength (for example, the lower portion where the pressure of cast-in-place concrete is high). Further, the shape-retaining muscles can be provided outside or inside the reinforcing bars, or only a predetermined portion can be provided outside and other portions can be provided inside. Further, the shapes of the precast member and the reinforcing bars embedded in the precast member are not limited to the above-described quadrangular cylindrical shape, but may be various polygonal cylindrical shapes such as an octagonal cylindrical shape, and may be, of course, cylindrical shapes. It is also possible to make the reinforcing bars multiple. Furthermore, the shape retainer can be partially, for example, a structure provided only at the upper and lower ends of the slit portion, as long as the shape of the precast member can be maintained, and in this case, along the horizontal direction, It can be provided only between the slit portions or closed in a hoop shape. In this case, a vertical bar as a reinforcing bar and a tubular bar around which a hoop bar or a spiral bar is wound are provided between the upper and lower shape retaining bars. Reinforcing bars may be provided for the purpose of preventing leakage.

[0032]

As described above in detail, according to the precast concrete-covered column of the present invention and its construction method,
Since the precast concrete formwork is formed on the side surface thereof, between the concrete on both sides of the slit part where the reinforcing bars are exposed, the shape-retaining bars and the reticulated formwork are provided separately from the reinforcing bars, The strength of the slits is improved by the shape-retaining bars, and therefore the strength of the entire precast concrete-covered column is also improved. At the same time, concrete cast into the inside of the precast concrete formwork by the mesh form is used. Will be prevented from leaking. Therefore, it is possible to prevent the occurrence of breakage and the like due to the formation of the slit portion and the reduction in the strength of this portion, thereby improving the reliability and enabling the preceding construction prior to the concrete construction of the wall of the precast concrete-covered column. Become.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a precast concrete formwork of the precast concrete covered column according to the first embodiment of the present invention.

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

FIG. 4 is a perspective view showing an example in which a part of a slit portion of a precast concrete formwork of the precast concrete covered column according to the first embodiment of the present invention is partially enlarged.

FIG. 5 is a front view showing one step of a method for constructing a precast concrete-covered column according to the first embodiment of the present invention.

FIG. 6 is a front view showing the next step of the method for constructing a precast concrete-covered column according to the first embodiment of the present invention.

FIG. 7 is a front view showing the next step of the method for installing a precast concrete-covered column according to the first embodiment of the present invention.

FIG. 8 is a front view showing a further next step of the method for constructing a precast concrete covered column according to the first embodiment of the present invention.

FIG. 9 is a perspective view showing another example in which a part of the slit portion of the precast concrete formwork of the precast concrete covered column according to the first embodiment of the present invention is enlarged.

FIG. 10 is a plan view showing a precast concrete formwork of a precast concrete covered column according to a second embodiment of the present invention.

FIG. 11 is a plan view showing a precast concrete formwork of a precast concrete covered column according to a third embodiment of the present invention.

FIG. 12 is a plan sectional view showing an example of arrangement of shape-retaining bars of a precast concrete formwork of a precast concrete covered column according to a fourth embodiment of the present invention.

FIG. 13 is a plan sectional view showing another example of the arrangement of the shape-retaining bars of the precast concrete formwork of the precast concrete-covered column according to the fourth embodiment of the present invention.

FIG. 14 is a plan sectional view showing still another example of the arrangement of the shape-retaining bars of the precast concrete formwork of the precast concrete-covered column according to the fourth embodiment of the present invention.

FIG. 15 is a plan sectional view showing an example of arrangement of shape-retaining bars of a precast concrete formwork of a precast concrete-covered column according to a fifth embodiment of the present invention.

FIG. 16 is a plan sectional view showing another example of the arrangement of the shape-retaining bars of the precast concrete formwork of the precast concrete-covered column according to the fifth embodiment of the present invention.

FIG. 17 is a cross-sectional plan view showing still another example of the arrangement of the shape-retaining bars of the precast concrete formwork of the precast concrete-covered column according to the fifth embodiment of the present invention.

FIG. 18 is a plan sectional view showing an example of arrangement of shape-retaining bars of a precast concrete formwork of a precast concrete-covered column according to a sixth embodiment of the present invention.

FIG. 19 is a plan sectional view showing another example of the arrangement of the shape-retaining bars of the precast concrete formwork of the precast concrete-covered column according to the sixth embodiment of the present invention.

FIG. 20 is a plan sectional view showing still another example of the arrangement of the shape-retaining bars of the precast concrete formwork of the precast concrete-covered column according to the sixth embodiment of the present invention.

[Explanation of symbols]

1,21,25,27,32,38 Precast concrete formwork 1A-1D, 21A-21D, 25A-25D, 27A
-27D, 32A-32D, 38A-38D Side part 2 Column part cast-in-place concrete 3 Column reinforcing bar 4 Column body 5 Horizontal bar 14A, 22A, 22C, 26A-26C, 28B, 2
8D, 33A, 33D, 39A, 39C Slit part 15 Reinforcing bar 16, 29, 30B, 30D, 31, 34, 35A, 3
5D, 36, 40A, 40C, 41A, 41C, 42
Shape-retaining streaks (retainers) 17 Concrete K Reticulated formwork

Claims (2)

(57) [Claims] 1. A precast concrete formwork in which a reinforcing bar is embedded in a cylindrical concrete, and a slit portion for joining a wall portion is formed on a side surface portion, the reinforcing bar being exposed. Provided inside the precast concrete formwork,
A column main body having a column reinforcing bar and concrete; and a horizontal bar protruding outward so that a part is embedded in the column main body and the other part is embedded in a wall from the slit portion, and is made of the precast concrete. The precast concrete-covered column, wherein the formwork is provided with a shape-retaining bar and a net-like formwork separately from the reinforcing bars at least between the concrete on both sides of the slit portion. 2. A reinforcing bar is embedded in a cylindrical concrete, and a slit is formed on a side surface thereof for joining a wall portion in which the reinforcing bar is exposed. Prepare a precast concrete formwork in which a shape-retaining reinforcing bar and a reticulated formwork are provided separately from the reinforcing bars between the concrete, and arranging the column reinforcing bars, and the precasting while inserting the column reinforcing bars inside. The concrete formwork is suspended and positioned, and a part of the horizontal streak is inserted from the slit portion of the precast concrete formwork and the other part is protruded outward, and concrete is inserted into the precast concrete formwork. A method for constructing a precast concrete-covered column, which comprises: