JP2013221342A - Precast concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a precast concrete which has a wholly compact shape and is transported and stored without requiring troublesome work.SOLUTION: The bases of truss reinforcements 33 are embedded in a single plate-like concrete part 31a. The truss reinforcement 33 each have wavy lattice reinforcements, a first end reinforcement joined and arranged between the wave head parts of the lattice reinforcements, and a second end reinforcement joined and arranged between the wave bottom parts of the lattice reinforcements. The first end reinforcement is located outside the concrete part, and the second end reinforcement is embedded in the concrete part.

Description

  The present invention relates to precast concrete suitable for use as a building frame.

Generally, precast concrete is used for building beams.
Such precast concrete is disclosed in Patent Document 1 and Patent Document 2.
In the precast concrete of Patent Document 1, square ring-shaped reinforcing bars are arranged inside a U-shaped bowl-shaped body.

  In the precast concrete of Patent Document 2, square ring-shaped streaks are provided inside a PC beam main body made of a plurality of concrete plates or bowl-shaped concrete plates.

JP-A-2-29424 JP 2004-124538 A

  As described above, the configurations described in Patent Document 1 and Patent Document 2 are large-sized because a square annular reinforcing bar or ribbed bar is provided in addition to the three-dimensional bowl-shaped body or PC beam main body. It was bulky, inconvenient to transport and store, and became one of the factors that pushed up construction costs.

  The present invention has been made paying attention to such problems existing in the prior art. The purpose is to provide precast concrete that is compact in overall shape and that does not require labor for transportation and storage.

In order to achieve the above object, the present invention is characterized in that a base portion of a truss bar is embedded in a concrete portion having a single plate shape.
Therefore, in this invention, since the precast concrete is comprised with the simple veneer-like concrete part and truss reinforcement, it is not bulky. For this reason, it does not take time and labor for transportation and storage, and the space required for it is also reduced. Therefore, the construction cost can be reduced.

  In the above-described configuration, the truss muscle includes a lattice-shaped lattice muscle, a first end muscle joined to the wave head of the lattice muscle, and a second end muscle joined to the wave bottom of each lattice muscle. Provided, the lattice bars, the first end bars and the second end bars extend to a rectangular concrete part, the first end bars are located outside the concrete part, and the second end bars are embedded in the concrete part. It is desirable.

In the above-described configuration, it is desirable that a gap is provided between the wave bottom portions of the pair of lattice muscles and the first end muscle is sandwiched between the wave heads.
It is preferable to use the above configuration for a beam of a reinforced concrete structure.

  It is preferable to use the above configuration as a form of the beam.

  As described above, according to the present invention, the overall shape is compact, and it takes less time for transportation and storage, and the construction cost can be reduced.

(A) And (b) is a schematic block diagram which shows the construction method of the reinforced concrete structure of 1st Embodiment in order. (A) And (b) is a schematic block diagram which shows the construction method of the reinforced concrete structure following FIG.1 (b) in order. The principal part side view which expands and shows the assembly state of the beam reinforcement in the assembly | attachment method of Fig.1 (a). Sectional drawing in the 4-4 line | wire of FIG. The partial perspective view which expands and shows the truss reinforcement in the beam of FIG. Sectional drawing which decomposes | disassembles and shows a part of beam of FIG. (A) is sectional drawing which shows the 1st modification of the beam in the assembly | attachment method of 1st Embodiment. (B) is sectional drawing which decomposes | disassembles and shows a part of the beam. (A) is sectional drawing which shows the 2nd modification of the beam in the assembly | attachment method of 1st Embodiment. (B) is sectional drawing which decomposes | disassembles and shows a part of the beam. (A) is sectional drawing which shows the 3rd modification of the beam in the assembly | attachment method of 1st Embodiment. (B) is sectional drawing which decomposes | disassembles and shows a part of the beam. (A) is sectional drawing which shows the 4th modification of the beam in the assembly | attachment method of 1st Embodiment. (B) is sectional drawing which decomposes | disassembles and shows a part of the beam.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.
First, the construction method of a reinforced concrete structure is demonstrated. As shown in FIGS. 1A and 1B and FIGS. 2A and 2B, the lower floor of the building is the N (integer) floor and the upper floor is the N + 1 floor. FIG. 1A shows a state in which the column reinforcement 21 of the column 51 on the N floor is constructed. In this state, the beam bars 22 are first assembled outside the building. Next, as shown in FIG. 1B, the beam 22 is installed at the position between the upper ends of the N-th column pillars 21, that is, at the position of the beam 52 on the (N + 1) th floor. Reference numeral 61 in the drawing denotes a hoop line.

  Here, the bottom of the concrete casting form of the beam 52 is formed of precast concrete (hereinafter simply referred to as PC) 31 made of a single plate shown in FIGS. The beam 22 is installed on the PC 31 in the vicinity of the outside of the building, and is then lifted together with the PC 31 by a crane or the like and installed at the position of the beam 52. Reference numeral 24 denotes a support for supporting the PC 31 (or the bottom frame of the beam form when no PC 31 is present).

  Also, before and after this, as shown in FIG. 1 (b), a floor plate 25 as a floor member made of half precast concrete is used for the horizontal construction surface surrounded by the beam bars 22 of the N + 1 floor. Lay. The floor plate 25 constitutes a floor formwork.

  Next, as shown in FIGS. 2 (a) and 2 (b), in the Nth floor, the arrangement of the reinforcing bars (not shown) between the columns 51, the installation of the molds 26 around the column reinforcing bars 21 and on both sides of the wall The side formwork (not shown) is installed on the side of the beam reinforcement 22 on the N + 1 floor, the wall reinforcement (not shown) between the column bars 21 and the formwork of the wall are installed.

Further, following the completion of the laying of the floor board 25, the reinforcing bars as the floor members and the column bars 21 are arranged on the floor board 25 on the (N + 1) th floor.
It should be noted that at least two of the arrangement of the reinforcing bars on the N floor, the installation of the wall formwork, the installation of the pillar form, the arrangement of the reinforcing bars on the floor plate 25 on the N + 1 floor, and the arrangement of the column reinforcement 21 on the N + 1 floor are performed simultaneously It is preferable to carry out in parallel from the viewpoint of shortening the construction period. Alternatively, at the same time as the installation of the beam bars 22 and the floor board 25 of the N + 1 floor, the arrangement of the reinforcing bars of the N floor, the installation of the wall formwork, the installation of the pillar formwork, the arrangement of the reinforcing bars on the floor board 25 of the N + 1 floor At least one of the above may be performed in parallel. Further, the arrangement of the N-level column bars 21 may be performed simultaneously with the installation of the N + 1-level beam bars 22 and the floor board 25.

  Thereafter, in the state of FIG. 2A or 2B, concrete is placed on the N-th column 51 and the wall, the N + 1-th beam 52, and the floor plate 25. The PC 31 constituting the bottom plate of the formwork of the beam 52 is buried and forms the concrete bottom surface of the beam 52.

As described above, according to the method for constructing the reinforced concrete structure, at least the reinforcement work for the beam 52 on the N + 1 floor and the formwork work for the floor on the N + 1 floor are performed in advance.
Next, the structure and construction method of the beam 52 will be described in detail.

As shown in FIGS. 3 to 6, the beam 52 includes a beam line 22 and a single-plate (flat plate) PC 31 that also serves as a beam bottom mold attached to the bottom surface of the beam.
A truss bar 33 made of a reinforcing bar is erected on the rectangular concrete portion 31 a of the PC 31. As shown in FIG. 5, each truss bar 33 has a wave shape and a plurality of pairs (two pairs in the embodiment) of lattice bars 33 a extending in the longitudinal direction of the concrete portion 31 a, and both lattice bars 33 a. It is joined between the wave heads, and is joined to one upper end bar 33b as a first end bar extending in the longitudinal direction of the concrete part 31a and the inner side of the lower end of the waveform of each lattice bar 33a. A plurality of lower end bars 33c as second end bars extending in the longitudinal direction of the portion 31a and a plurality of bars which are joined in a erected state at predetermined intervals across the lower end bars 33c and extend in the short direction of the concrete portion 31a. And the laying bar 33d. And the lower end part of the waveform of each lattice line 33a, each lower end line 33c, and each installation line 33d are embed | buried in the concrete part 31a.

  As shown in FIGS. 3, 4, and 6, the reinforcing bar set 32 of the beam 22 has a plurality of main bars 34 extending in parallel to the length direction of the beam 22 and a predetermined interval in a state of surrounding the main bars 34. It is arranged at intervals, and is constituted by a plurality of stirrups 35 and a binding state by a binding line. Each stirrup 35 is inserted inside the truss bar 33 on the PC 31 and opened upward, and the lower first divided piece 35A constituting the horizontal band and the opening of the first divided piece 35A. The upper second divided piece 35 </ b> B that opens downward to cover the end is divided. On both sides of the opening end of the first divided piece 35A, locking portions 35a that can be locked to the main bars 34 located at the upper ends of both sides are bent.

  The PC 31 having the truss bars 33 is manufactured at a factory and is carried into a construction site. Further, the reinforcing bar set 32 is arranged on the truss bar 33 while passing the split pieces 35A and 35B inside the truss bar of the PC 31 outside the reinforced concrete structure at the construction site.

Therefore, according to this embodiment, the following effects can be obtained.
(1) In the embodiment, the reinforcement work for the beam 52 on the N + 1 floor and the formwork work for the floor on the N + 1 floor are performed prior to the other work. Therefore, the installation of the form of the beam 52 on the N + 1 floor, the rebar construction of the wall on the N floor and the installation of the form of the wall and pillar, the reinforcement of the floor on the N + 1 floor, and the reinforcement of the column 51 It is possible to carry out simultaneously in parallel and shorten the construction period.

  (2) In the embodiment, when the reinforced concrete structure having the beam reinforcement 22 is constructed, the beam reinforcement 22 constituting the beam reinforcement 22 is assembled outside the structure, and then the beam reinforcement 22 is installed between the column reinforcements 21. I am doing so. For this reason, the beam bars 22 can be easily installed between the column bars 21 while being suspended by a crane or the like. On the other hand, when the beam bars 22 are arranged at the position of the beam, the work is complicated because it is an aerial work or a work in a narrow space in the formwork. Therefore, in this embodiment, the installation of the reinforcing bar set 32 constituting the beam bars 22 and the operation of arranging the beam bars 22 between the column bars 21 can be performed efficiently, and the construction period can be shortened. . Further, by arranging the reinforcing bars at the construction site, it is not necessary to transport the large bulky reinforcing bar set 32 by using a transportation means such as a truck, so that it is possible to reduce labor and cost for that purpose. Therefore, according to this embodiment, the construction cost of a building can be reduced.

  (3) In this embodiment, the bottom surface of the beam is composed of PC31. For this reason, by installing the reinforcing bar set 32 on the upper side of the PC 31, the beam 52 can be easily formed using the PC 31 as a formwork, which contributes to a reduction in construction cost.

  (4) In this embodiment, since PC31 is comprised with the simple flat concrete part 31a and the truss reinforcement 33, it is not bulky. For this reason, it does not take time and labor for transportation and storage, and the space required for it is also reduced. Therefore, the construction cost can be reduced also from this point.

(Example of change)
Next, first to fourth modification examples of the embodiment will be described.
In the first modified example shown in FIGS. 7A and 7B, almost the same as in the case of the above embodiment, the stirrup 35 constituting the reinforcing bar set 32 is a lower first opening that opens upward. It is divided into a divided piece 35A and an upper second divided piece 35B that opens downward. On both sides of the opening end of the first divided piece 35 </ b> A, a locking portion 35 a that can be locked with the pair of main bars 34 located on the second step from the bottom of both sides is bent. On both sides of the opening end of the second divided piece 35B, a locking portion 35b that can be locked to the pair of main bars 34 located at the lower ends of both sides is bent.

  In the second modified example shown in FIGS. 8A and 8B, in the same manner as in the first modified example, the stirrup 35 constituting the reinforcing bar set 32 is a lower side opening upward. The first divided piece 35A is divided into an upper second divided piece 35B that opens downward. On both sides of the opening end of the first divided piece 35A, a locking portion 35a that can be locked to the pair of main bars 34 located on the second stage from the top of both sides is bent. On both sides of the opening end of the second divided piece 35B, a locking portion 35b that can be locked with the pair of main bars 34 located at the second stage from the bottom of both sides is bent.

  In the third modified example shown in FIGS. 9A and 9B, the stirrup 35 constituting the reinforcing bar set 32 has a lower first divided piece 35A that is linear, and an upper side that opens downward. The second divided piece 35B is divided. Engaging portions 35a that can be engaged with the pair of main bars 34 located at the lower ends of both sides are bent at both ends of the first divided piece 35A. On both sides of the opening end of the second divided piece 35B, a locking portion 35b that can be locked to the pair of main bars 34 located at the lower ends of both sides is bent.

  In the fourth modified example shown in FIGS. 10A and 10B, the stirrup 35 constituting the reinforcing bar set 32 has a first divided piece 35 </ b> A on one side that forms a straight line, and an opening toward one side. And is divided into the second divided piece 35B on the other side. Engaging portions 35a that can be engaged with a pair of main bars 34 located at both upper and lower ends on one side are bent at both end edges of the first divided piece 35A. Engagement portions 35b that can be engaged with the pair of main bars 34 located at the upper and lower ends on one side are bent above and below the opening end of the second divided piece 35B.

  26 ... Formwork, 31 ... Precast concrete, 31a ... Concrete part, 32 ... Reinforcement group, 33 ... Truss, 33a ... Lattice, 52 ... Beam.

Claims (5)

Precast concrete in which the base of truss bars is embedded in the concrete part that forms a single plate. The truss muscle includes a lattice muscle having a wave shape, a first end muscle joined to the wave head of the lattice muscle, and a second end muscle joined to the wave bottom of each lattice muscle, The first end bar and the second end bar extend to the rectangular concrete part, the first end bar is located outside the concrete part, and the second end bar is embedded in the concrete part. The precast concrete according to claim 1. The precast concrete according to claim 2, wherein a gap is provided between the wave bottom portions of the pair of lattice bars, and the first end bars are sandwiched between the wave head portions. The precast concrete according to any one of claims 1 to 3, wherein the precast concrete is used for a beam of a reinforced concrete structure. The precast concrete according to claim 4, wherein the precast concrete is used as a form of the beam.