JP2011094335A - Method for constructing floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and rapidly construct a high-quality floor slab by utilizing a precast concrete member for floor framing so as to solve the problems of a prestressed concrete beam and a half prestressed concrete beam, in the case of the precast concrete member in which a hollow hole with both opened ends is formed in a longitudinal direction and into which prestress is introduced by a plurality of prestressed concrete steel wires embedded along the hollow hole. <P>SOLUTION: This floor slab 1 is constructed through the following steps: the hollow rod-like precast concrete member 3, in which the hollow hole (a) with both the opened ends is formed in the longitudinal direction and into which the prestress is introduced by the plurality of prestressed concrete steel wires 2 embedded along the hollow hole (a), is laid across a girder 4; a deck plate 5 with a reinforced truss is laid across the precast concrete member 3; and concrete 6 is cast-in-place on them. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for constructing a reinforced concrete floor slab.

  In constructing reinforced concrete floor slabs, it is already common to use precast concrete members (PC beam) or half precast concrete members (half PC beam) as the beam that is a component of the floor assembly. Has been proposed by Patent Documents 1, 2 and the like. A precast concrete member (PC small beam) for a small beam is embedded with an upper main bar and a lower main bar, and stirrups that are wound around the outer periphery of the main bar and reinforced with shear. Half precast concrete members for half beams (half PC beam) are embedded with the bottom main bar and stirrup in a state where the top side of the stirrup protrudes from the concrete surface, the top main bar is placed on site, and the top is cast in the field. It is constructed so as to be combined with the concrete made into a small beam.

  The PC beam has a tendency to increase in weight on the other hand, while bar arrangement work and concrete placement work are omitted, and is inconvenient for transportation by truck or the like and small transportation on the site. On the other hand, the half PC beam is lighter, but the upper main bar is arranged at the site and the concrete is placed on the upper part. Therefore, the construction of the floor slab tends to take more time than the PC beam.

  By the way, as precast concrete members for floors and walls, prestress is introduced by a plurality of PC steel wires embedded in the longitudinal direction with hollow holes opened at both ends in the longitudinal direction. A precast concrete member (trade name: spun cleat) is known. This precast concrete member is not embedded with upper and lower main bars and stirrup, like PC small beams, but has high strength because prestress is introduced, and has a hollow hole, Specific gravity is lighter and lighter than precast concrete members of the same thickness.

Japanese Patent Publication No.7-88688 Japanese Patent Publication No. 7-51805

  The present invention uses a precast concrete member in which a pre-stress is introduced into a floor set in which a hollow hole opened at both ends is formed in a longitudinal direction and prestress is introduced by a plurality of PC steel wires embedded along the hollow hole. Therefore, it is an object of the present invention to solve the above-mentioned problems in the PC beam and the half PC beam and to easily and quickly construct a high-quality floor slab.

  In order to achieve the above object, the present invention provides a hollow in which pre-stress is introduced by a plurality of PC steel wires in which hollow holes opened at both ends are formed in the longitudinal direction and embedded along the hollow holes. A bar-shaped precast concrete member is installed on a girder, a prefabricated floor slab is installed on a precast concrete member, and concrete is cast on-site on these to construct a floor slab (claim 1).

The invention according to claim 2 is the floor slab construction method according to claim 1, characterized in that the large beam is configured by hitting concrete on-site.

  Invention of Claim 3 is the construction method of the floor slab of Claim 1, Comprising: A large beam is synthesize | combined with the half precast concrete member and the concrete put in-situ on the upper part, It is characterized by the above-mentioned. .

  Invention of Claim 4 is the construction method of the floor slab in any one of Claims 1-3, Comprising: An edge part reinforcement is above the edge part of the hollow-rod-shaped precast concrete member erected in the large beam. The upper horizontal reinforcing bar is placed in the hollow hole at the end of the precast concrete member, and the upper horizontal reinforcing bar is crossed to the upper part of the upper main bar of the large beam, and is bent diagonally downward from the end. The cast-in-place concrete that has been inserted into the hollow hole by inserting the lower end side and the lower horizontal reinforcing bar part of the inclined reinforcing bar part of the lifting bar comprising the inclined reinforcing bar part and the lower horizontal reinforcing bar part folded horizontally from the end part. It is characterized by being embedded in

  According to the first aspect of the present invention, a hollow rod-like shape in which hollow holes opened at both ends are formed in the longitudinal direction and prestress is introduced by a plurality of PC steel wires embedded along the hollow holes. Precast concrete members are installed on large beams, prefabricated floor slabs are installed on precast concrete members to form floor assemblies, and hollow bar-shaped precast concrete members and ready-made floor slabs, both factory products, are used as floor assembly components. Therefore, a high-quality floor assembly can be easily constructed. Here, as the ready-made floor slab, a deck plate, a half precast floor slab (half PC floor slab), or the like is suitably used in addition to a deck plate with a reinforcing bar truss.

  In particular, a hollow rod-shaped precast concrete member in which prestress is introduced by a plurality of PC steel wires embedded in the longitudinal direction with open hollow holes at both ends and embedded along the hollow holes is a PC beam. Unlike main and half PC beam, main reinforcement and shear reinforcement are not embedded, but because pre-stress is introduced, it has high strength and becomes a part of the floor slab. , Ready-made floor slab → hollow rod-like precast concrete member → can flow to large beams. In addition, the hollow rod-shaped precast concrete member has a hollow hole, so its specific gravity is lighter and lighter than that of the PC beam of the same thickness, which is advantageous for transportation by truck or on-site. It is not necessary to arrange the upper main bars on site like a half PC beam. As a result of these, a high quality floor slab can be constructed easily and quickly.

  In addition, as the large beam, as in the invention described in claim 2, it may be configured by hitting concrete on the spot, but as in the invention according to claim 3, the large beam is a half precast concrete member. It is preferable to synthesize it with the concrete that has been cast in the upper part in that the formwork for the large beam can be omitted.

  According to the invention described in claim 4, the end reinforcing bar is arranged above the end of the hollow rod-like precast concrete member installed on the girder, and inside the hollow hole at the end of the precast concrete member. An upper horizontal reinforcing bar part that is arranged to intersect the upper part of the upper main bar of the girder, an inclined reinforcing bar part that is bent diagonally downward from its end part, and a lower horizontal reinforcing bar part that is folded back horizontally from that end part Inserting the lower end of the sloped reinforcing bar part and the lower horizontal reinforcing bar part and embedding it in the cast-in-place concrete that has flowed into the hollow hole, so that the joint between the hollow rod-shaped precast concrete member and the girder is strong. It is possible to prevent the occurrence of cracks at the joint.

It is a schematic perspective view of the floor slab constructed by the method of the present invention. It is a schematic plan view of a floor set. It is a top view of the principal part of a floor set. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is sectional drawing of the principal part of a floor slab. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is sectional drawing of the principal part of a floor slab. It is a schematic perspective view of the floor set which shows other embodiment of this invention. It is sectional drawing of the principal part. It is sectional drawing of the principal part.

  FIG. 1 shows a floor slab 1 constructed according to the method of the present invention, and FIG. 2 shows a floor set. As shown in FIGS. 2 to 4 and 6, the floor assembly is formed by a plurality of PC steel wires 2 in which hollow holes “a” opened at both ends are formed in the longitudinal direction and embedded along the hollow holes “a”. As shown in FIGS. 1, 5, and 7, a hollow rod-shaped precast concrete member 3 into which prestress is introduced is constructed on a large beam 4 and a deck plate 5 with a reinforcing bar truss is constructed on the precast concrete member 3. In addition, the floor slab 1 is constructed by hitting concrete 6 on the top. Until a predetermined strength is developed in the concrete 6, the precast concrete member 3, the deck plate 5 with a reinforcing bar truss, and the formwork 7 for the large beam are supported by a pipe support 8 that is planted on the lower floor.

  As the hollow rod-shaped precast concrete member 1, for example, trade name: spun cleat is used. The girder 4 is constructed by performing beam placement of the beam reinforcement (upper main bar 9a, lower main bar 9b, stirrup 9c, etc.) 9 and concrete 6 in the formwork 7. The illustrated deck plate 5 with a reinforcing bar truss is constituted by a discarded frame 5a made of a galvanized steel plate and a reinforcing bar truss 5c attached to the upper surface of the discarded frame 5a via a suspension member 5b. 5d is an upper chord member of the reinforcing bar truss 5c, 5e is a lower chord member, and 5f is an oblique member.

  Reference numeral 10 denotes an end reinforcing bar arranged above the end of the hollow rod-shaped precast concrete member 3 installed on the large beam 4. 3, 4, 6, and 7, 11 is an upper horizontal reinforcing bar portion 11 a that is arranged so as to intersect with the upper portion of the upper main reinforcing bar 9 a of the girder 4, and is bent obliquely downward from the end thereof. This is a lifting bar comprising an inclined reinforcing bar part 11b and a lower horizontal reinforcing bar part 11c folded back horizontally from its end part. The lower end side of the inclined reinforcing bar portion 11b and the lower horizontal reinforcing bar portion 11c of the lifting bar 11 are inserted into the hollow hole a at the end of the precast concrete member 3 and flow into the hollow hole a in the state where the floor slab 1 is constructed. It is embedded in the concrete 6. However, as shown in FIG. 7, the concrete 6 does not need to flow into all the inside of the hollow hole a, and it is sufficient that the concrete 6 is buried to the extent that the adhesion strength between the concrete 6 and the lower horizontal reinforcing bar portion 11 c can be maintained. Incidentally, in the present embodiment, the concrete 6 is embedded up to the position of 100 mm including the extra length from the end of the lower horizontal reinforcing bar portion 11 c toward the center of the precast concrete member 3. b is a notch formed at the upper end of the end of the precast concrete member 3.

  According to the above configuration, the hollow rod-shaped precast in which the hollow holes a opened at both ends are formed in the longitudinal direction, and prestress is introduced by the plurality of PC steel wires 2 embedded along the hollow holes a. A concrete member 3 is installed on a large beam 4 and a deck plate 5 with a reinforcing bar truss is installed on a precast concrete member 3 to form a floor assembly. Since the deck plate 5 with a reinforcing bar truss is used, a high-quality floor assembly can be easily constructed.

In particular, a hollow rod-shaped precast concrete member 3 having hollow holes a open at both ends in the longitudinal direction and prestressed by a plurality of PC steel wires 2 embedded along the hollow holes a is as follows: Unlike PC beam and half-PC beam, the main bar and shear reinforcement bar are not embedded, but because pre-stress is introduced, it has high strength and becomes a part of floor slab 1, and the floor slab The load acting on 1 can flow from the deck plate 5 with a reinforcing bar truss to the hollow bar-shaped precast concrete member 3 to the girder 4. Moreover, since the hollow rod-shaped precast concrete member 3 has the hollow hole a, its specific gravity is lighter and lighter than that of a PC beam having the same thickness, which is advantageous for transportation by truck or on-site. There is also no need to arrange the upper main bars on site like a half PC beam. As a result of these, a high quality floor slab can be constructed easily and quickly.

  8 to 10 show another embodiment of the present invention. This embodiment is characterized in that the girder 4 is composed of the half precast concrete member 4a and the concrete 6 cast on the top thereof. In the half precast concrete member 4a for large beams, concave grooves c into which the end portions of the hollow rod-like precast concrete member 3 are fitted are formed at intervals of the precast concrete member 3. And the state which constructed | assembled the floor slab 1 by inserting the concrete 6 in-situ, and inserting the lower end side of the inclination reinforcement part 11b of the lifting reinforcement 11 and the lower horizontal reinforcement part 11c inside the hollow hole a of the edge part of the precast concrete member 3 7, as in the case of FIG. 7, it is configured to be embedded in the concrete 6 flowing into the hollow hole a from the opening end of the hollow hole a and the notch b of the precast concrete member 3. However, since the embedding of the concrete 6 in the hollow hole a is the same as that in the above embodiment, the description thereof is omitted.

  The cross-sectional shape of the precast concrete member 3 may have a recessed portion on both side surfaces as shown in FIGS. 4 and 5, but as shown in FIG. 8, the cross-sectional shape has smooth both side surfaces. It is desirable to prevent the concrete 6 from flowing out from the gap between the groove c and the precast concrete member 3.

  According to said structure, a formwork for large beams can be abbreviate | omitted and a high quality floor slab can be constructed | assembled still more easily and rapidly. Other configurations and operations are the same as those in the embodiment of FIGS.

  The floor slab construction method of the present invention can be used for construction of floor slabs in office buildings, apartment houses, commercial facilities and the like.

DESCRIPTION OF SYMBOLS 1 Floor slab 2 PC steel wire 3 Hollow rod-shaped precast concrete member 4 Large beam 4a Half precast concrete member 5 Deck plate with a reinforcing bar truss 5a Dismantling frame 5b Hanging material 5c Reinforcing bar truss 5d Upper chord material 5e Lower chord material 5f Diagonal material 6 Concrete 7 type Frame 8 Pipe support 9 Beam reinforcement 9a Upper main bar 9b Lower main bar 9c Stirrup 10 End reinforcement bar 11 Lifting bar 11a Upper horizontal bar part 11b Inclined bar part 11c Lower horizontal bar part a Hollow hole b Notch c Concave groove

Claims (4)

  A hollow rod-shaped precast concrete member in which pre-stress is introduced by a plurality of PC steel wires embedded in the longitudinal direction with hollow holes opened at both ends and embedded along the hollow holes, A method for constructing a floor slab, comprising laying a plate on a precast concrete member and constructing a floor slab by placing concrete on the spot on the spot.   The method for constructing a floor slab according to claim 1, wherein the girder is constructed by hitting concrete on-site.   The method for constructing a floor slab according to claim 1, wherein the girder is composed of a half precast concrete member and concrete cast in place on the upper part thereof.   End reinforcement bars are placed above the ends of the hollow-rod-shaped precast concrete members installed on the girder, and the top of the upper main bars of the girder crosses inside the hollow holes at the end of the precast concrete members. An inclined reinforcing bar portion of a lifting bar comprising an upper horizontal reinforcing bar portion that is arranged at the end, an inclined reinforcing bar portion that is bent obliquely downward from the end portion thereof, and a lower horizontal reinforcing bar portion that is folded back horizontally from the end portion thereof The floor slab construction method according to any one of claims 1 to 3, wherein a lower horizontal reinforcing bar portion and a lower horizontal reinforcing bar portion are inserted and embedded in the cast-in-place concrete flowing into the hollow hole.

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