JP5051766B2 - Joint structure of precast floor slab and beam - Google Patents

Description

  The present invention relates to a joint structure between a precast floor slab and a beam mainly employed in a reinforced concrete structure (RC structure).

  When constructing a reinforced concrete structure (RC structure), it is roughly divided into a method of constructing concrete by on-site casting and a method of pre-fabricating precast concrete members in advance and bringing them into the site for assembly.

  The precast method requires rapid construction because the main structural members such as columns, beams, and floor slabs are manufactured at the factory as described above, and these can be carried to the site and assembled to greatly improve construction efficiency. In this case, many of the latter precast methods have been adopted, and recently, many of them have been adopted for high-rise apartments with more than 30 floors.

  When the precast method is adopted, the so-called full precast method for producing a precast member as a solid cross section and the beam is produced in a U-shape if it is a beam, and a reinforcing bar is placed on the inside to fill the concrete. There is a half-precast method, and in reality, these are used properly in consideration of these advantages and disadvantages, but in any case, as long as they are assembled on site, joining of precast members is inevitable.

  Here, since a large bending moment is generated at the joint between the main structural members, especially during an earthquake, how to construct such a joint is the biggest issue for securing earthquake resistance in the precast method. However, it is not an exaggeration, and many proposals have been made.

  For example, Patent Document 1 states that “a pair of full PC floor plates 10 are placed on the beam 2 so that a placement space Sp1 is formed between the sides, and the reinforcing bars of one floor plate 10 are placed in the space Sp1. The connecting portion 12b1 of the other floor plate and the connecting portion 12b1 of the reinforcing bar of the other floor board 10 are close to each other and parallel to each other, and one steel sleeve Sv is fitted to the connecting portion of the two reinforcing bars, The wedge Wg is press-fitted into the center hole of the steel sleeve to connect the two rebars, the headed stud Sd is fixed to the beam 2 in the space Sp1, and concrete is placed in the space Sp1, A method of adhering full PC floorboards is disclosed in which floorboards are secured to beams and full PC floorboards are secured together.

  Patent Document 2 states that “the connecting end 4 of the precast concrete floor plates 2, 3 is opposed to the upper surface of the beam, and is protruded horizontally from the connecting end at an appropriate interval. Is inserted between the connecting bars 5 facing each other, and a bar-like bar 6 protruding from the beam upper surface is inserted into the connecting bars 4 and 5, and reinforcing bars are provided on the upper surfaces of the connecting bars 4 and 5. 7 is perpendicularly arranged, and the cast-in-place concrete 9 is placed between the joint ends 8 ”.

  Further, Patent Document 3 states that “the first precast concrete member and the second precast concrete member that are joined adjacent to each other are provided with locking bars that protrude from the respective joining side ends, and the both A locking part is provided at the front part of the reinforcing bar, and an annular restraining bar is arranged so as to surround both locking parts of the opposing locking bars, and between the joining side ends of both precast concrete members to be joined, There is disclosed a “joint structure of precast concrete members” in which concrete or mortar is placed so that the locking bars and the binding bars are embedded.

JP 2002-161603 A JP-A-9-165860 JP 2004-3231 A

  However, these are made by filling concrete between the two floor slabs facing each other, thereby exposing two sets of reinforcing bars exposed from each floor slab and reinforcing bars, rods or studs extending from the top of the concrete beam. Because it is a structure that expects the strength of the joint to be the adhesion between the reinforcing bar or bar and the concrete or the bearing pressure of the concrete against the stud, There is a problem that the workability is reduced due to the complicated crossing of studs, studs, and reinforcing bars, and that it requires joining a lot of work to ensure the quality related to the joint strength because it is joined via cast-in-place concrete. It was.

  The present invention was made in consideration of the above-mentioned circumstances, and when the precast floor slab is joined to the edge of the concrete beam by placing it on the top end of the concrete beam, while improving the workability during construction, An object of the present invention is to provide a joint structure between a precast floor slab and a beam capable of firmly joining the precast floor slab and a concrete beam in a state where quality control is easy.

  In order to achieve the above object, the joint structure of the precast floor slab and the beam according to the present invention, as described in claim 1, is an exposed end portion of the slab reinforcement embedded in the precast floor slab and extending from the edge end surface thereof, The exposed portion of the beam reinforcement extending from the top end of the concrete beam on which the edge of the precast floor slab is placed, and the connecting means for connecting the exposed end portion of the slab reinforcement and the exposed portion of the beam reinforcement, A cylindrical body having an oval cross-sectional shape that is inserted in a state where the exposed end portion of the slab bar and the exposed part of the beam bar overlap each other by a predetermined length, and a wall portion that constitutes the cylindrical body. And a wedge member inserted through a wedge insertion hole formed in each of the pair of flat wall portions and press-fitted between the exposed end portion of the slab bar and the exposed portion of the beam bar.

  The precast floor slab and the beam joining structure according to the present invention have a stirrup streak as the beam streak and an upper horizontal portion of the stirrup streak as the exposed portion, and the cylindrical body is preliminarily formed in the exposed portion. The concrete beam is formed so as to be inserted.

  Moreover, the joint structure of the precast floor slab and the beam according to the present invention is such that the beam bar is a C-shaped reinforcing bar and the opposite end portions of the C-shaped reinforcing bar are the exposed portions and the connection is made. Each of the cylinders of the pair of connecting means is inserted through the end portions, and the exposed end portions of the slab bars are arranged in the state where the cylinders are coaxially arranged. It is inserted through the body.

  Moreover, the joint structure of the precast floor slab and the beam according to the present invention includes the precast floor slab composed of a pair of precast floor slabs placed on the top ends of the concrete beams so that the edge end faces face each other. In addition, of the pair of precast slabs, the exposed end of the slab reinforcement embedded in one precast slab and the exposed end of the slab reinforcement embedded in the other precast slab are exposed to the beam reinforcement. It is alternately connected to the part.

  In the joint structure of the precast floor slab and the beam according to the present invention, the cylindrical member and the wedge member constitute the connecting means, and the exposed end portion of the slab bar extending from the edge end surface of the precast floor slab is connected to the connecting means described above. It connects with the exposed part of the beam reinforcement extended from the top end of a concrete beam via.

  In this way, the exposed end of the slab bar embedded in the precast floor slab is firmly connected to the exposed part of the beam bar extending from the concrete beam. Compared to conventional joint structures that depend on the bond strength of steel, it is possible to ensure a more stable joint strength and eliminate the need for lap joints between reinforcing bars, so when placing reinforcements or placing concrete The workability is greatly improved.

  The concrete beam is a beam using concrete as a compression structural element, and is a concept including a reinforced concrete beam, a steel reinforced concrete beam, and a prestressed concrete beam. The concrete beam may be manufactured as a precast concrete member at the factory, or may be constructed on site with concrete casting.

  In the present invention, the concrete beam is exposed before the precast slab is joined. In that sense, the exposed part of the beam is not filled with a concrete beam of the entire cross section but is filled with filled concrete. It becomes a concrete beam of all cross sections in the state.

  Beam reinforcement means any reinforcing bar that is arranged in the beam cross section regardless of the connection with the precast slab, and typically refers to a shear reinforcement. In addition, the exposed part of the beam is the part exposed to the space that extends between the precast slab and the concrete beam before joining or the space that spreads between the precast slab and the concrete beam. Indicates a portion embedded in the concrete filled in the space.

  The shape and structure of the beam streak are arbitrary as described above. However, when the beam streak is constituted by, for example, a stirrup streak (a rib streak), the upper horizontal portion of the stirrup streak is used as an exposed portion, and the exposed portion is formed. What is necessary is just to form a concrete beam so that the cylinder of a connection means may be beforehand penetrated by the part. This concrete beam may be manufactured as a precast member or may be constructed of cast-in-place concrete.

  Further, in the case where the beam reinforcement is constituted by, for example, a C-shaped reinforcing bar, the reinforcing bars are arranged so that the opposing end portions of the C-shaped reinforcing bar are on the upper side, and the end portions thereof are exposed portions. The connecting means is a pair of connecting means, and the cylinders of the pair of connecting means are respectively inserted into the end portions, and the exposed ends of the slab muscles are arranged in a state where the cylinders are arranged coaxially. What is necessary is just to penetrate each cylinder. Regardless of whether this concrete beam is manufactured at the factory or constructed on site, if the distance between the opposing ends is narrow, the beam is expanded and each cylinder is inserted. Can be placed.

  In addition, in the case where the beam bars are constituted by, for example, a U-shaped reinforcing bar, the U-shaped end portions are disposed so that the end portions are exposed, and the end portions are exposed portions. What is necessary is just to insert the horizontal upper-end line | wire arrange | positioned so that may be connected to the cylinder of a connection means. This concrete beam, whether it is factory production or construction on site, does not matter.

  For example, when the precast slab in each invention described above is joined to a concrete beam erected along the outer wall of the structure, it is joined to the concrete beam as a single unit. In many cases, a pair of precast slabs are assembled on the top end of a concrete beam so that their edge portions face each other.

  Even in such a case, it goes without saying that each of the above-described inventions can be applied. As a configuration in that case, for example, of the pair of precast slabs, the exposed end portion of the slab muscle embedded in one precast slab and the other A configuration is possible in which the exposed ends of the slab bars embedded in the precast floor slab are alternately connected to the exposed sections of the beam bars.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a joint structure between a precast floor slab and a beam according to the present invention will be described with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG. 1 is a perspective view showing a joint structure between a precast floor slab and a beam according to the present embodiment, and FIG. 2 is a plan view and a side view of the same. As can be seen from these drawings, the joint structure 1 between the precast floor slab and the beam according to the present embodiment is such that the edge portions 2a and 2b of the precast floor slabs 3a and 3b face each other. 4a and 4b are placed on the top end 8 of the concrete beam 5, and the exposed end portion 7a of the slab bar 6a that is embedded in the precast floor slab 3a and extends from the edge end surface 2a is connected to the concrete via a connector 10 as a connecting means. Connected to the upper horizontal portion 11 as an exposed portion of the stirrup muscle 9 which is a beam reinforcement arranged in the beam 5, and to the upper horizontal portion 11 of the stirrup muscle 9 arranged next to the stirrup muscle. Is connected to the exposed end portion 7b of the slab bar 6b embedded in the precast floor slab 3b and extending from the edge end surface 2b via the connector 10.

  As shown in FIG. 3, the connector 10 is formed in a cylindrical body 31 having an oval cross-sectional shape and a pair of opposing flat wall portions 32 and 32 among the wall portions constituting the cylindrical body. A wedge member 34 is inserted into the wedge insertion holes 33 and 33.

  Here, the cylindrical body 31 is configured so that the exposed end portion 7a of the slab muscle 6a and the upper horizontal portion 11 of the stirrup muscle 9 are overlapped by a predetermined length, and the slab muscle 6b is exposed. The end portion 7b and the upper horizontal portion 11 of the stirrup muscle 9 are configured to be inserted in a state where they overlap each other by a predetermined length. The wedge member 34 is configured to be press-fitted between the exposed end portion 7a of the slab muscle 6a and the upper horizontal portion 11 of the stirrup muscle 9, and the exposed end portion 7b and the star of the slab muscle 6b. It is configured to be press-fitted between the upper horizontal portion 11 of the lap muscle 9.

  A plurality of stirrup bars 9 are arranged in the material axis direction at a predetermined pitch as shear reinforcement bars of the concrete beam 5, and the exposed end portion 7a of the slab bar 6a and the slab bar 6b are arranged on the upper horizontal portion 11 of the stir bar bar 9. The exposed end portions 7b are alternately connected.

  In order to construct the joint structure 1 between the precast floor slab and the beam according to the present embodiment, the precast floor slabs 3a and 3b and the concrete beam 5 are manufactured as precast members, and after these are carried to the site, the concrete beam 5 Is installed.

  As shown in FIGS. 1 and 2, the concrete beam 5 is inserted into the cylindrical body 31 of the connector 10 from the end of the stirrup bar 9 in advance and temporarily fixed to the upper horizontal part 11 of the stirrup bar 9. What is necessary is just to cast concrete in the state and produce it.

  Next, the precast floor slab 3 a is placed on the top end 8 of the concrete beam 5, and the exposed end 7 a of the slab bar 6 a extending from the precast floor slab 3 a is inserted into the cylindrical body 31. The same applies to the precast floor slab 3b, and this is placed on the top end 8 of the concrete beam 5, and the exposed end 7b of the slab bar 6b extending from the precast floor slab 3b is inserted into the cylindrical body 31.

  When the installation of the precast floor slabs 3a and 3b and the insertion operation into the cylindrical body 31 are completed, the wedge member 34 is driven into the wedge insertion holes 33 and 33, and the upper horizontal portion 11 of the stirrup muscle 9 and the precast floor slab 3a. Are connected to the exposed end portion 7a of the slab bar 6a extending from the upper horizontal portion 11 of the stirrup bar 9 and the exposed end portion 7b of the slab bar 6b extending from the precast floor slab 3b. In press-fitting the wedge member 34 through the wedge insertion holes 33, 33, a conventionally known wedge driving machine may be appropriately selected and used.

  Next, after reinforcing bars are placed in the space between the edge end faces 2a and 2b of the precast floor slabs 3a and 3b as needed, the concrete is filled and the joining operation is completed.

  As explained above, according to the joint structure 1 of the precast floor slab and the beam according to the present embodiment, the joining tool 10 is configured by the cylindrical body 31 and the wedge member 34, and the edge end surfaces of the precast floor slabs 3a and 3b are formed. Since the exposed end portions 7a and 7b of the slab bars 6a and 6b extending from 2a and 2b are connected to the upper horizontal part 11 of the stirrup bars 9 arranged in the concrete beam 5 through the connector 10, precast The exposed end portions 7a and 7b of the slab bars 6a and 6b embedded in the floor slabs 3a and 3b can be firmly connected to the stirrup bars 9 of the concrete beam 5.

  Therefore, the precast floor slab 3a, the precast floor slab 3b, and the concrete beam 5 are integrated through the joint 10, and thus, compared to a conventional joint structure that depends on the adhesion strength of concrete or mortar, It becomes possible to ensure a more stable joint strength and eliminate the need for a lap joint between reinforcing bars, so that the workability when placing bars and placing concrete is significantly improved.

  In the present embodiment, the case where the pair of precast floor slabs 3a and 3b is placed on the concrete beam 5 so that the end surfaces of the precast floor slabs face each other is explained. However, the precast floor slabs 3a and 3b are precast on the concrete beam along the outer wall of the structure. It goes without saying that the present invention can also be applied to the case of placing a floor slab.

  In such a modified example, in the above-described embodiment, only the precast floor slab 3b is omitted, and the other configurations are the same, and thus the description thereof is omitted here.

  Further, in the present embodiment, it is assumed that the concrete beam 5 is manufactured as a precast member, but the concrete beam 5 may be constructed on site instead. Even in that case, the procedure for inserting the cylindrical body 31 of the connector 10 into the stirrup muscle 9 is the same as that in the above-described embodiment.

  Further, in the present embodiment, the stirrup muscle 9 is folded in a normal form, that is, in a rectangular shape and both ends are folded to form hooks, and the whole is closed. The beam reinforcement 41 shown in FIG.

  In the modification shown in the figure, the beam bars 41 are formed in a substantially rectangular shape like the stirrup bars 9, but the end portions 42 and 42 are opposed to each other with a gap δ therebetween. Each of the end portions is an exposed portion.

  In order to construct a joint structure between a precast floor slab and a beam using the beam reinforcement 41, first, the concrete beam 5a is manufactured at the factory so as to expose the end portions 42, 42 of the beam reinforcement 41, or on the site. To construct.

  Next, the two cylinders 31 and 31 are respectively inserted into the end portions 42 and 42 of the beam bar 41 using the gap δ, and the slab bar 6a extending from the precast floor slab 3a placed on the top end of the concrete beam. The exposed end portion 7a is inserted into the cylindrical bodies 31 and 31.

  At this time, the cylindrical bodies 31 and 31 are temporarily held coaxially, and the exposed end 7a of the slab muscle 6a may be inserted straight in this state.

  The same applies to the precast floor slab 3b, and the two cylindrical bodies 31, 31 are respectively inserted into the end portions 42, 42 of the other beam bars 41 arranged next to the beam bar 41, and extend from the precast floor slab 3b. The exposed end portion 7b of the slab muscle 6b is inserted through the cylindrical bodies 31 and 31.

  When the installation of the precast floor slabs 3a and 3b and the insertion work into the cylindrical bodies 31 and 31 are completed, the two wedge members 34 and 34 are driven into the wedge insertion holes 33 and 33 of the cylindrical bodies 31 and 31, The end 42 and the exposed end 7a of the slab muscle 6a, and the end 42 and the exposed end 7b of the slab muscle 6b are connected to each other.

  Next, after reinforcing bars are placed in the space between the edge end faces 2a and 2b of the precast floor slabs 3a and 3b as needed, the concrete is filled and the joining operation is completed.

  According to this modification, the beam bars 41 are closed via the exposed end portions 7a of the joints 10, 10 and the slab muscle 6a, or the exposed end portions 7b of the joint tools 10, 10 and the slab muscle 6b, so that the star Similar to the wrap bars 9, it can act as a shear reinforcement, and, as in the above-described embodiment, the precast floor slab 3 a, the precast floor slab 3 b and the concrete beam 5 a are integrated with each other through the joint 10. Is possible.

  Moreover, you may use the beam reinforcement 51 shown in FIG.

  In the modified example shown in the figure, the beam line 51 is formed so as to be bent in a substantially U-shape and arranged so that end portions 52 and 52 provided with hooks are on the upper side. Are exposed portions.

  In order to construct a joint structure between a precast floor slab and a beam using the beam reinforcement 51, first, the concrete beam 5b is manufactured at the factory so that the ends 52, 52 of the beam reinforcement 51 are exposed upwardly, Or build on-site.

  Next, the horizontal upper end reinforcement 53 spanned between the end portions 52 of the beam bar 51 is inserted into the cylindrical body 31, and the exposed end portion 7 a of the precast floor slab 3 a is inserted into the cylindrical body 31.

  Next, both ends of the horizontal upper bar 53 are bound to the ends 52 and 52 of the beam bar 51 using a binding line or the like.

  When the installation of the precast floor slab 3a and the insertion operation into the cylindrical body 31 are completed, the wedge member 34 is driven into the wedge insertion hole 33 of the cylindrical body 31, and the horizontal upper end line 53 and the exposed end part 7a of the slab bar 6a Are connected to each other.

  After connecting the precast floor slab 3b in the same manner, reinforcing bars are placed in the space between the edge end faces 2a, 2b of the precast floor slabs 3a, 3b as necessary, and then concrete is filled. To complete the joining work.

  According to such a modification, the exposed end 7a of the slab bar 6a and the exposed end 7b of the slab bar 6b are firmly connected to the horizontal upper bar 53 via the connector 10, and the horizontal upper bar 53 is a beam bar. Since it becomes a shear reinforcement with 51, it becomes possible to mutually integrate the precast floor slab 3a, the precast floor slab 3b, and the concrete beam 5b via the connector 10, similarly to embodiment mentioned above.

The perspective view which showed the joining structure 1 of the precast floor slab and beam which concern on this embodiment. It is the figure which similarly showed the joining structure 1 of a precast floor slab and a beam, (a) is a top view, (b) is an arrow view of the AA line direction. It is the figure which showed the connector 10, (a) showed the mode which connected the exposed end part 7a of the slab muscle 6a, and the stirrup muscle 9, (b) showed the mode that the wedge member 34 was driven. Figure. The perspective view which showed a mode that the exposed end part 7a of the slab reinforcement 6a extended from the precast floor slab 3a was connected with the beam reinforcement 41 which concerns on a modification. The perspective view which showed a mode that the exposed end part 7a of the slab reinforcement 6a extended from the precast floor slab 3a was connected with the beam reinforcement 51 which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Junction structure 2a, 2b edge part surface 3a, 3b Precast floor slab 4a, 4b Edge 5,5a, 5b Precast floor slab concrete beam 6a, 6b Slab reinforcement 7a, 7b Exposed end 8 Top end 9 Stirrup (beam)
DESCRIPTION OF SYMBOLS 10 Connector 31 Cylindrical body 33, 33 Wedge insertion hole 34 Wedge member 41, 51 Beam reinforcement

Claims (4)

An exposed end portion of the slab reinforcement embedded in the precast floor slab and extending from the edge end face thereof, an exposed portion of the beam reinforcement extending from the top end of the concrete beam on which the edge of the precast floor slab is placed, and an exposed end of the slab reinforcement And a connecting means for connecting the exposed portion of the beam reinforcement, and the connecting means is inserted in a state where the exposed end portion of the slab reinforcement and the exposed portion of the beam reinforcement overlap each other by a predetermined length. Of the oval cylindrical body and the wall portion constituting the cylindrical body, the exposed end portion of the slab bar and the beam bar are inserted through wedge insertion holes respectively formed in a pair of opposed flat plate wall portions. A joint structure of a precast floor slab and a beam, characterized by comprising a wedge member press-fitted between the exposed portion and the exposed portion. 2. The concrete beam is formed by using the beam stirrup as a stirrup streak and the upper horizontal portion of the stirrup as the exposed portion, and the cylindrical body is inserted into the exposed portion in advance. Structure of precast floor slab and beam. The beam bars are C-shaped reinforcing bars, and the opposite ends of the C-shaped reinforcing bars are the exposed portions, and the connecting means are provided in a pair, and the cylinders of the pair of connecting means are The joint between the precast floor slab and the beam according to claim 1, wherein each end is inserted, and an exposed end of the slab bar is inserted into each cylinder in a state where the cylinders are coaxially arranged. Construction. The precast slab is composed of a pair of precast slabs placed on the top end of the concrete beam so that the edge end surfaces face each other, and one of the pair of precast slabs The exposed end portion of the embedded slab reinforcement and the exposed end portion of the slab reinforcement embedded in the other precast floor slab are alternately connected to the exposed portion of the beam reinforcement. Bonded structure of precast floor slab and beam.

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