JPH0822533B2 - Method for manufacturing pillar formwork for steel reinforced concrete - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a concrete formwork used when constructing columns of a steel frame reinforced concrete (SRC) building.

[0002]

2. Description of the Related Art When a pillar of a steel-framed reinforced concrete building is constructed by a formwork (panel) method, a wooden formwork (plywood) is used as a material for the formwork. Recently, precast concrete formwork has been developed due to problems such as waste of formwork disposal, depletion of wood resources, and reduction of craftsmen who make formwork.

As for the precast concrete formwork, a concrete formwork corresponding to a conventional wooden formwork is produced in a factory, which is brought to a work site and covered with a steel frame rebar that has been previously assembled, and concrete is placed therein. You can build a pillar just by doing. Further, the concrete formwork does not require the work of removing the formwork after completion unlike the wooden formwork, which leads to a reduction in the discharge of formwork waste materials. In addition, due to the simplification of the construction, the work time can be reduced to half that of the conventional method, which is an excellent advantage.

By the way, a conventional precast concrete formwork used for constructing columns of a steel-framed reinforced concrete building is a column-shaped hollow body constructed from the beginning, which is vertically divided into two, for example, a U-shape. Alternatively, we manufacture a semi-circular shaped molded product, bring it in to the site, and combine the two molded products at the site to form a framework.

[0005]

Therefore, the above-mentioned half-divided molded product always undergoes deformation such as distortion, warpage, and twisting during the process of curing to stocking in the manufacturing process, that is, during the progress of hardening of concrete. Will end up. Then, the above-mentioned deformation such as distortion, warpage, and twist becomes more remarkable as the thickness of the molded product is thinner. Since this concrete formwork is also designed to be very thin for the purpose of use, the above-mentioned distortion and deformation cannot be avoided. Therefore, when the molded products are covered on the steel frame rebar at the site, there is a problem that the mating surfaces of the left and right molded products do not match because the molded products are deformed, a large gap is opened, and the surface is wavy. Have.

The present invention has been made in view of the problems of the above-mentioned conventional techniques, and an object thereof is to make a split precast concrete mold used for constructing columns of a steel-framed reinforced concrete building. It is an object of the present invention to provide a method for efficiently manufacturing a precast concrete formwork that does not cause distortion, warpage, twisting, or the like with respect to the formwork, and as a result can be matched accurately.

[0007]

Means for Solving the Problems The technical means taken by the present invention to achieve the above-mentioned object is to provide a space inside a molding space of a hollow cylinder defined by an outer mold and an inner mold. A partitioning material that divides the left and right parts into two parts, and insert nuts are bolted to the inner die or outer die at symmetrical positions with the partitioning material sandwiched between them, and the molding between the outer die and the inner die is performed. Fill the space with the cement-based material, remove the inner mold when the cement-based material hardens, and use the insert nut embedded in the molded product to set the connecting jig on the left and right molded products that sandwich the partitioning material. Finally, the molded product is removed from the outer mold, and the partition material that divides the molded product into two parts is removed to obtain a two-part form frame. That is, in the process from molding to curing, a closed hollow cylinder is used, and after waiting for the increase in strength and rigidity, the partitioning material that divides this hollow cylinder into left and right parts is removed to produce a mold that can be used in the field. This is a characteristic method.

The shape of the hollow cylinder is a square,
Examples thereof include rectangular hollow cylinders such as regular hexagons and regular octagons, circular hollow cylinders such as circles and ellipses, and deformed hollow cylinders such as stars. Further, the hollow cylinder described above can be molded by a molding method that is generally used today, such as a centrifugal molding method or a vibration molding method. Further, the molding material for the hollow cylindrical body may be either a cement-based material or a material in which a synthetic resin is mixed.

Further, the mounting position of the partitioning member that divides the hollow cylindrical body into two is not limited to the central position where the hollow cylindrical body is divided into the right and left, and the cross-section of the steel rebar can be covered from the outside. Place it in two places that form a U-shape.

[0010]

According to the above means, since the hardening progress process of concrete is performed with the hollow cylindrical body whose cross-sectional shape is closed, deformation such as warping or twisting does not occur, and the strength and rigidity are sufficient. The imparted hollow cylinder is obtained. And
The left and right molds obtained by removing the partition material attached to the hollow cylindrical body form a pair because the mating surfaces are the same, and they can be accurately matched in the field use. Moreover, since the left and right molds that are partitioned by the partition material are connected by the connecting jig, the left and right mold frames that are divided by the removal of the partition material do not fall apart, and stock and transportation can be performed efficiently. You can

[0011]

Embodiments of the present invention will now be described with reference to the drawings. Inside the corners of the outer mold A having a substantially square cross section, the inner surface of the outer mold A is spaced from the inner surface by a predetermined distance. The mold B is arranged to define the forming space a of the rectangular hollow cylindrical body,
A partition member 1 that divides the molding space into two parts is vertically fixed to the opposite position by a bolt 2 from the outside of the outer mold A, and an insert nut 3 is provided at a symmetrical position with the partition member 1 interposed therebetween. It is fixed to the mold B with bolts 4 to form a molding mold. Then, this molding die is rotated by a centrifugal molding method which is well known today, and the cement material is filled into the rotating die to fill the molding space a with the cement material to form the hollow rectangular cylinder C. . It should be noted that the insert nut 3 should be attached at a position close to the opening ends on both sides along the axial direction of the molding die so that the inner die B can be removed and the connecting jig 6 can be easily attached in the next step. To be able to In addition, it is optional to increase the strength of the molding frame by inserting and arranging the reinforcing material 5 in the molding space a.

The cement-based material supplied to the molding die forms a hollow rectangular cylinder C, and when it is hardened to some extent, the bolt 4 screwed into the insert nut 3 embedded and fixed in the cylinder is removed to remove the inner metal mold. B is removed, and then the connecting jig 6 is fixed by the bolt 7 using the insert nut 3. Therefore, two connecting jigs 6 are attached to the hollow prismatic cylinder C at one opening end, and a total of four connecting jigs 6 are attached on both sides. Then, at the stage where the curing and hardening of the hollow prismatic cylinder C is promoted, the bolts 2 which hold the partition material 1 on the inner surface of the outer mold A are removed, and then the outer mold A is disassembled into a plurality of members to form a hollow prismatic cylinder. The body C is taken out, and thereafter, the partition member 1 which divides the tubular body into two in a vertical split shape is tapped from the inside to remove, so that molds 8 and 8'having a substantially U-shaped cross section are obtained.

As a form of the molds 8 and 8'manufactured by interposing the partition member 1 at two locations on the peripheral wall of the hollow prismatic cylinder C, for example, as shown in FIG. A partition material is placed along it to form a two-divided formwork with the same U-shape, or as shown in Fig. 4 (b), cut along the diagonal line of a square to form a substantially L-shaped cross-section, etc. Is mentioned. It should be noted that the two molds manufactured by dividing the two parts by the partitioning material are not limited to the shapes of the same shape illustrated,
Needless to say, for example, a U-shape having different long and short dimensions may be used.

As described above, by removing the partition material 1 arranged on the peripheral wall from the hollow prismatic cylinder C, the mold frames 8 and 8'divided in two are covered from the outside so as to surround the steel rebar D, A flat plate-like connecting plate (not shown) is bridged over the molds 8 and 8 ', and bolts are used to connect the two molds by using the insert nut 3 embedded in the molds. It should be noted that, when joining and connecting the forms 8 and 8 ', it is free to interpose packing between the joining surfaces of the two forms, if necessary. Further, the molds 8 and 8'covered and joined from the outside so as to surround the steel rebar D are obtained by vertically dividing the tubular body into two parts by a partition member to form a pair. The contact surface with and becomes the joining surface as it is, and it is possible to improve the alignment accuracy when the molds are aligned to form a tubular shape. Moreover, since the two-divided formwork is connected by the connecting jig 2 as it is, the formwork obtained by removing the partition material does not fall apart, and the formwork is transported in a pair state to the site to assemble the formwork. Can be done. Further, although the above-mentioned embodiment is an embodiment in which the insert nut is attached to the inner die, the insert nut may be attached to the outer die.

[0015]

As described in claim 1, the method for manufacturing a column frame for steel reinforced concrete according to the present invention comprises forming a cylindrical body in a molding die for forming a hollow rectangular cylinder or a hollow circular cylinder. A partitioning material that is divided into two in a vertical split is arranged, and insert nuts are bolted to the mold at symmetrical positions with the partitioning material sandwiched, and this molding mold is filled with cementitious material. At the time of hardening, the mold is removed and the partitioning material is removed to obtain a vertically split two-part formwork, so there is no deformation such as distortion, warpage, or twisting, and it is possible to match it accurately. The mold can be manufactured efficiently.

Moreover, before the partition material is removed, the insert nuts embedded in the cylinder are used to connect the two molds separated by the partition material with a connecting jig, so that the partition material is removed. Since the two molds thus obtained do not become disjointed and always form a pair, they can be easily transported to the site and assembled at the site. The insert nut for attaching the connecting jig has an advantage that it can be used for connecting the molds to be joined together when the molds are mounted on the steel rebar.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding die used in a centrifugal molding method showing an embodiment of a manufacturing method according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which an inner mold is removed from a molding mold and a connecting jig is attached.

FIG. 3 is a cross-sectional view of a state where a mold is obtained by removing an outer mold and a partition member.

FIG. 4 is an explanatory view showing a state in which a steel frame is covered with a molded frame.

[Explanation of symbols]

 A ... Outer mold B ... Inner mold C ... Hollow cylinder D ... Steel frame 1 ... Partition material 3 ... Insert nut 6 ... Connection jig

Claims (1)

[Claims] 1. A partitioning member that divides the space into left and right parts in a molding space of a hollow cylindrical body defined by an outer mold and an inner mold,
Place the insert nut in a symmetrical position across the partition material by bolting it to the inner mold or the outer mold, and fill the molding space between this outer mold and the inner mold with a cement-based material, and cement. When the system material has hardened, remove the inner mold, set the connecting jig to the left and right molded products that sandwich the partitioning material using the insert nut embedded in the molded product, and finally remove the molded product from the outer mold. A method for manufacturing a pillar formwork for steel-framed reinforced concrete, which comprises removing a partitioning material that separates a molded product into two parts to obtain a formwork that is divided into two parts.