JP2014095256A - Ribbed precast concrete plate, and method for separately placing concrete in composite floor slab and beam using the ribbed precast concrete plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability when a slab and a beam are different in concrete strength, like in the case that concrete having a normal strength is used as cast-in-place concrete of a composite floor slab formed by placing cast-in-place concrete on a ribbed precast concrete plate and a high strength concrete is used as cast-in-place concrete of beams for supporting both ends of the composite floor slab, or like in the case that high strength concretes different in strength are used for the composite floor slab and beam respectively.SOLUTION: Wire mesh like partition materials 4 for placing joint sections are vertically installed on a top face of a ribbed precast concrete plate 1 in which a plurality of ribs 3 extending in a principal direction on a top face of a flat plate part 2 and in the vicinity of both ends in the principal direction are protrusively provided, in a state that lower ends of the partition materials 4 are embedded within the thickness of the ribbed precast concrete plate.

Description

The present invention relates to a ribbed precast concrete plate and a method of placing concrete between a composite floor slab and a beam constructed using the same, and more specifically, a plurality of ribs extending in the main direction are protruded from the upper surface of a flat plate portion. Using normal-strength concrete as the cast-in-place concrete for the composite floor slab, which is a structural integration of the ribbed precast concrete plate and the concrete cast in-situ above it, cast the beam to support both ends of the composite floor slab. The present invention relates to a technique for improving workability when concrete strength of slabs and beams is different, such as when high-strength concrete is used as concrete, or when high-strength concrete of different strength is used for composite floor slabs and beams.

When concrete is handed over at a span intermediate position of a general floor slab, a wire mesh partition material such as a lath wire mesh or rib lath is often used for the joint portion. In addition, when using a low-rigid wire mesh partition material such as a lath wire mesh for the floor slab joint, it is difficult to stably stand on the floor formwork, but the rebar is bent into a rectangular shape. A vertical reinforcing bar is arranged in each part of the processed frame to prepare a frame, and a wire mesh partition is bound and fixed to this frame with a wire, and this wire mesh partition is attached to the upper surface of the floor mold. It is also known from Patent Document 1 to be fixed by a pier or the like to be independent.

However, the floor slab is a synthetic floor slab in which the precast concrete plate with ribs and the concrete cast in-situ above it are structurally integrated, using ordinary strength concrete as the cast-in-place concrete of the synthetic floor slab, When high-strength concrete is used as the cast-in-place concrete for the beams that support both ends in the main direction of the composite floor slab, the following problems arise.

First, because a precast concrete plate with ribs is used as the casting formwork for the synthetic floor slab, it is used for the splicing part on the upper surface of the precast concrete plate with ribs and in the vicinity of both ends in the main direction (longitudinal direction of the ribs). When installing the wire mesh partition material, the metal mesh partition material is required to have a complex shape with an uneven shape along the valley shape between the ribs, with the upper edge being horizontal and the lower edge being horizontal. Therefore, the handling of the wire mesh partition material is troublesome.

Second, pre-stress is introduced into the precast concrete plate with ribs by PC steel (for example, PC steel stranded wire) embedded in the main direction. It is desirable to avoid the opening of the wire mesh, and it is impossible to nail the piers and the like for fixing the wire mesh partitioning material, so it is difficult to make the wire mesh partitioning material stable and independent.

Thirdly, if the wire mesh partition material for the joint is applied to the end face in the main direction of the ribbed precast concrete plate, the wire mesh partition material has a simple shape with no irregularities on the lower edge. However, in this case, the wire mesh partition material used as the splicing part will be placed in the beam width. Since high-strength concrete will be handed over, it is difficult to ensure the beam performance by using high-strength concrete as the cast-in-place concrete for the beam.

JP 2000-45521

The present invention has been made in view of the above-mentioned problems, and the object of the invention is a synthetic floor formed by structurally integrating a precast concrete board with ribs and concrete cast in place above it. When using normal strength concrete as the slab cast-in-place concrete and using high-strength concrete as the cast-in-place concrete for the beams that support both ends of the composite floor slab, or using high-strength concrete with different strength for the composite floor slab and the beam Precast concrete plate with ribs that can improve the workability when the concrete strength of the slab and the beam is different, as in the case of the It is to provide.

In order to achieve the above object, technical measures taken by the present invention are as follows. That is,
The ribbed precast concrete plate according to the invention described in claim 1 is spliced on the upper surface of the ribbed precast concrete plate in which a plurality of ribs extending in the main direction is projected on the upper surface of the flat plate portion and in the vicinity of both ends in the main direction. The metal mesh partition material for part is erected in a state in which the lower edge is embedded in the thickness of the ribbed precast concrete board.

Invention of Claim 2 is a precast concrete board with a rib of Claim 1, Comprising: The upper edge of the wire-mesh-like partition material for splicing parts is made into the diameter of the distribution bar mounted in a rib. It is characterized by being positioned above the rib by a corresponding height.

Invention of Claim 3 is a precast concrete board with a rib of Claim 1, Comprising: The upper edge of the metal-mesh-like partition material for joining parts is located in the same height as the upper surface of a rib It is characterized by that.

According to a fourth aspect of the present invention, there is provided a composite floor slab and beam concrete placing method, wherein the precast concrete plate with ribs according to the second or third aspect is laid over beam forms on both sides, and orthogonal to the ribs on the ribs. An upper layer in which a plurality of notches are formed on the lower edge after placing the reinforcing bars at the required intervals in the direction in which the upper end main bars are placed on the distributing bars at the required intervals. The second wire mesh partition material for the side splicing part is aligned with the wire mesh partition material provided upright in the vicinity of both ends of the ribbed precast concrete plate, and the upper end main bar fits into the notch at the lower edge. After placing and fixing the wire mesh partition with a wire rod, normal strength concrete is placed on the precast concrete plate with ribs, and high strength concrete is placed inside the beam form. Synthetic floor It is characterized in that separate out the concrete of the probe and the beam.

According to the invention described in claim 1, the wire mesh partition material for the joint portion is previously provided on the upper surface of the ribbed precast concrete plate and in the vicinity of both ends in the main direction, and the lower edge of the ribbed precast concrete plate. Since it is erected in a state where it is embedded within the thickness, installation work of the wire mesh partitioning material at the site can be greatly saved, and nails such as piers to make the wire mesh partitioning material self-supporting Since it is unnecessary, it is possible to avoid the release of prestress by nailing the precast concrete part.

According to the second aspect of the present invention, the upper edge of the wire mesh partition material for the splicing portion is positioned above the rib by a height corresponding to the diameter of the distribution bar placed on the rib. Therefore, if the reinforcing bars are placed on the ribs in a direction perpendicular to the ribs, and the upper main bars are placed on these distributing bars in the main direction, the upper main bars are the upper edges of the wire mesh partition material. Since the wire mesh partition material does not become an obstacle to the work of arranging the upper main bar, it is easy to accurately arrange the upper main bar at a predetermined position.

In addition, a second wire mesh partition material for the upper layer joint portion in which a notch portion into which the upper end main bar is fitted in advance at the lower edge is prepared, and the second wire mesh partition material is used as the wire mesh partition material. The wire mesh partition for vertical joints corresponding to the slab thickness is arranged in a state in which the upper end main bar is fitted in the notch portion of the lower edge and is bound and fixed to the wire mesh partition material with a wire. Can be completed. Therefore, when placing the upper main bar on the strength bar, the troublesome work of inserting the upper main bar from the side into the mesh of the wire mesh partitioning material can be omitted, and the upper end main bar is bent at both ends.
That is, it is possible to easily arrange the upper main bars which are bent at both ends toward the inside of the beam in order to secure the fixing length with the beam concrete.

According to the invention described in claim 3, since the upper edge of the wire mesh partitioning material for the splicing portion is positioned at the same height as the upper surface of the rib, in addition to the effect of the invention of claim 2, the rib Even if the precast concrete plates with a stack are stacked, there is no possibility that the wire mesh partitioning material for the joint portion will be deformed, and there is an effect that the precast concrete plates with ribs can be easily transported and stored.

According to the invention described in claim 4, in addition to the effects of the invention described in claim 2 or 3, in addition to the joint portion between the normal strength concrete for the synthetic floor slab and the high strength concrete for the beam (Position position) will be closer to the center of the span than the end face in the main direction of the precast concrete board with ribs (position slightly entering the composite floor slab side from the beam side face), and a part of the high-strength concrete will be in the composite floor. Since it enters the slab side, normal strength concrete and high-strength concrete are placed on the safe side, and it is easy to ensure the beam performance.

It is a schematic perspective view of the precast concrete board with a rib which concerns on this invention. It is a vertical front view of the precast concrete board with a rib which concerns on this invention. It is a vertical side view explaining the concrete floor slab and the beam concrete placement method concerning the present invention. It is a vertical side view explaining the process following FIG. It is the sectional view on the AA line of FIG. It is a vertical side view explaining the process following FIG. It is a vertical side view explaining the process following FIG. It is a vertical front view of the precast concrete board with a rib which shows other embodiment of this invention. It is a vertical front view of the precast concrete board with a rib which shows other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an example of a ribbed precast concrete board 1 according to the present invention. This ribbed precast concrete plate 1 is spliced to the upper surface of a ribbed precast concrete plate in which a plurality of ribs 3 having a flat upper surface extending in the main direction are projected on the upper surface of the flat plate portion 2 and in the vicinity of both ends in the main direction. The metal mesh partition material 4 for part is erected in a state where the lower edge 4a is embedded in the thickness of the ribbed precast concrete plate. The upper edge 4 b of the wire mesh partition member 4 is positioned above the rib 3 by a height corresponding to the diameter of the power distribution bar placed on the rib 3. As the wire mesh partitioning material 4, for example, a lath wire mesh, rib lath or the like is employed. Reference numeral 5 denotes a mesh line (welded wire mesh) embedded in the flat plate portion 2. PC steel (for example, PC steel strand) at the position corresponding to the rib 3
6 is embedded in the main direction, and prestressing by a pretension system is introduced into the precast concrete plate 1 with ribs.

Next, the concrete floor slab and beam concrete placement method using the ribbed precast concrete plate 1 will be described.

As shown in FIG. 3, the precast concrete board 1 with a rib is constructed over the beam formwork 7 of both sides. Next, as shown in FIG. 4, the reinforcing bars 8 are placed on the ribs 3 in the direction perpendicular to the ribs 3 at a required interval, and the upper main bars 9 are arranged on these distributing bars 8 in the main direction. Are placed at required intervals. Both end portions of the upper end main reinforcement 9 are bent toward the inside of the beam in order to secure a fixing length with the beam concrete.

After the upper main bar 9 is arranged, as shown in FIGS. 4 and 5, the second metal mesh partition material (the wire mesh partition material 4 and the upper layer side joint portion having a plurality of notches a formed in the lower edge is formed. The same lath wire mesh, rib lath, etc. are employed.) 10 is placed along the wire mesh partitioning material 4 erected in the vicinity of both ends of the precast concrete plate 1 with ribs, and the upper end main reinforcement 9 is the lower edge. It arrange | positions in the state engage | inserted in the notch part a, and it binds and fixes to the said metal-mesh-like partition material 4 with a wire, and completes the metal mesh-like partition for perpendicular | vertical joint parts corresponding to slab thickness.

In this state, as shown in FIG. 6, the ordinary strength concrete C ₁ on the ribbed precast concrete plate 1, the interior of the beam-type frame of high strength concrete C ₂ to each Da設, as shown in FIG. 7 In addition, the composite floor slab 11 in which the precast concrete plate 1 with ribs and the normal strength concrete C ₁ cast on the top thereof are structurally integrated and the beam 12 made of the high strength concrete C _{2 on} the spot are constructed.

According to said structure, the metal-mesh-like partition material 4 for joint parts is previously set | placed on the upper surface of the precast concrete board 1 with a rib in the main direction both ends vicinity, The lower edge 4a of the precast concrete board 1 with a rib Since it is erected in a state of being embedded in the thickness, the installation work of the wire mesh partitioning material 4 at the site can be omitted, and there is no need for nail fastening such as a berth to make the wire mesh partitioning material 4 self-supporting. The release of prestress due to nailing the precast concrete part can be avoided.

Moreover, since the upper edge 4b of the wire mesh partition material 4 for the joint portion is positioned above the rib 3 by a height corresponding to the diameter of the distribution bar 8 placed on the rib 3, the rib 3 is placed in a direction perpendicular to the ribs 3, and an upper end main reinforcement 9 is placed in the main direction on these distribution reinforcements 8, the upper end main reinforcement 9 becomes the wire mesh partition 4. Since the wire mesh partitioning material 4 does not become an obstacle to the work of arranging the upper main bar 9, it is easy to accurately arrange the upper main bar 9 at a predetermined position. As shown in the figure, even the upper end main reinforcement 9 having both ends bent can be easily arranged.

Also, usually strength concrete C ₁ and the high strength concrete C ₂ the hit joints (strikes separated position) of the span center side than the main direction end face of the ribbed precast concrete plate 1 (beam side for beams for synthesis Slabs Since the part of the high-strength concrete C ₂ enters the synthetic floor slab 11 side, the normal-strength concrete C ₁ and the high-strength concrete are placed. C ₂ is arranged on the safe side, and it is easy to secure the beam performance.

FIG. 8 shows another embodiment of the present invention. This embodiment is characterized in that the wire mesh partition material 4 for the joint portion is set to have a vertical width such that the upper edge 4b is positioned at a height corresponding to the upper surface of the synthetic floor slab. It is preferable to form the upper end main bar notches b in advance at predetermined intervals on the upper edge 4b of the wire mesh partition member 4 in order to save labor for the upper end main bar in the field. . Since the other configuration is the same as that of the embodiment of FIG. 2, the same reference numerals are given to the same components, and the description thereof is omitted.

FIG. 9 shows another embodiment of the present invention. This embodiment is characterized in that the upper edge 4 b of the wire mesh partition material 4 for the joint portion is positioned at the same height as the upper surface of the rib 3. Other configurations are:
Since it is the same as that of embodiment of FIG. 2, the same code | symbol is attached | subjected to the same structural member and description is abbreviate | omitted.

Although not shown in the drawings, in the concrete floor slab and beam concrete placing method using the ribbed precast concrete board 1 according to the present invention, instead of the second wire mesh partitioning material 10 for the upper layer side joint portion, plywood, piers, etc. It is also possible to perform the upper layer side joining using a wooden partition material. In this way, a step of removing the wooden partition material is required, but the cost can be reduced by reducing the amount of use of lath wire mesh, rib lath and the like.

DESCRIPTION OF SYMBOLS 1 Precast concrete board with a rib 2 Flat plate part 3 Rib 4 Wire mesh partition material 4a Lower edge 4b Upper edge 5 Mesh reinforcement 6 PC steel material 7 Beam formwork 8 Load reinforcement 9 Top main reinforcement 10 Second metal mesh partition material 11 Composite floor slab 12 Beam C ₁ Normal strength concrete C ₂ High strength concrete a, b Notch

Claims (4)

On the top surface of the flat plate portion, a ribbed pre-cast concrete plate with a plurality of ribs extending in the main direction is provided on the top surface and in the vicinity of both ends in the main direction. A ribbed precast concrete board characterized by being erected in a state embedded in the thickness of the precast concrete board. 2. The upper edge of the wire mesh partition material for the splicing part is positioned above the rib by a height corresponding to the diameter of the distribution bar placed on the rib. Ribbed precast concrete board. The precast concrete board with ribs according to claim 1, wherein the upper edge of the wire mesh partitioning material for the joint portion is located at the same height as the upper surface of the rib. A precast concrete plate with ribs according to claim 2 or 3 is laid over beam forms on both sides, and the reinforcing bars are placed on the ribs in a direction perpendicular to the ribs at predetermined intervals. After placing the upper main bars in the main direction at the required intervals, the second wire mesh partitioning material for the upper layer-side joint with a plurality of notches formed on the lower edge of the ribbed precast concrete board Along with the wire mesh partition material standing upright in the vicinity of both ends, and arranged in a state where the upper end main bar is fitted into the notch portion of the lower edge, after being bound and fixed to the wire mesh partition material with a wire A composite floor slab characterized by placing normal strength concrete on a precast concrete plate with ribs and high-strength concrete inside the beam form to separate the composite floor slab and beam concrete, Beam con REIT beating classification method.

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