JP2000001938A - Precast concrete board and floorboard structure of building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability by constituting an upper end member of a truss structure reinforcing body having the lower part embedded in a concrete board main body under the horizontal plate part by an upper end steel frame having vertical ribs on the under surface. SOLUTION: This floorboard structure has a reinforcing body 3 of a truss structure having the lower part embedded in a concrete board main body 1 and the upper part projecting from the upper surface of the concrete board main body 1. The reinforcing body 3 is composed of lower end reinforcements 7 being arranged under an upper end steel frame 6 and extending in the same direction as the upper end steel frame 6 and lattice reinforcements 8 extending in the same direction by bending in a zigzag shape so as to alternately join the upper end steel frame 6 and the lower end reinforcements 7. The lower end reinforcements 7 and the lower parts of the lattice reinforcements 8 are embedded in the concrete board main body 1. Thus, flexural rigidity of a precast concrete board is enhanced, and even if the precast concrete board is formed for a long span, timbering and a small beam are not required. Thus, a cost is reduced, a construction period is shortened, and field workability is advantageously improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a precast concrete slab and a floor slab structure of a building.

[0002]

2. Description of the Related Art Japanese Utility Model Publication No. 3-28084 describes a precast concrete slab in which a lower portion of a truss bar is embedded in a concrete slab body. The truss bar includes an upper bar bar (upper chord bar), a lower bar bar (lower bar bar), and a lattice bar which is bent in a zigzag manner so as to alternately connect the two bar bars.

[0003] Japanese Patent Application Laid-Open No. 3-59250 discloses a precast concrete slab in which a receiving metal for hanging on a beam is embedded at an end portion.

[0004]

However, in the case of the conventional precast concrete slab in which the truss bars are embedded, when the span between the beams on which the truss is erected is long, a separate support is required. This is because the flexural rigidity of the precast concrete slab itself is not so high, and the precast concrete slab bends under its own weight when erected. This leads to an increase in man-hours, deterioration of workability on the lower floor, etc., which is disadvantageous for shortening the construction period, reducing costs, and saving labor. For this reason, precast concrete slabs are rarely used for long-span buildings, and when they are used, design changes such as inserting small beams in the middle are inevitable.

[0005] Further, in the precast concrete slab, since the concrete slab main body is erected on the opposite beam, a thick concrete slab is formed on the beam. This means that a layered space between the upper floor and the lower floor is required, which is equal to the height of the beam and the thickness of the concrete slab. means. On the other hand, it is conceivable to separately embed a receiving metal as described in the above-mentioned patent publication in the concrete plate body. However, reinforcing around the base of the receiving metal embedded in the concrete slab with a reinforcing bar, etc. A separate reinforcing means is required.

This application provides an invention relating to a precast concrete slab and a floor slab structure of a building which solves such a problem.

[0007]

In order to solve the above-mentioned problems, in the invention of this application, a steel frame having a vertical rib is used instead of the upper reinforcing bar of the truss bar, or an upper member such as the upper reinforcing bar is used. Both ends are projected outward from the concrete slab main body, and the projected portions are used for erection on beams.
Hereinafter, the invention of this application will be specifically described.

The invention according to claim 1 is a precast concrete slab having a concrete slab main body and a truss structure reinforcing member having a lower part embedded in the concrete slab main body and an upper part projecting from an upper surface of the concrete slab main body. The reinforcing body of the truss structure has an upper end steel frame having a longitudinal rib extending in a longitudinal direction on a lower surface of the horizontal plate portion, and a lower end reinforcing bar disposed below the upper end steel frame and extending in the same direction as the upper end steel frame. And a lattice bar bent in a zigzag and extending in the same direction so as to alternately connect the upper end steel frame and the lower end reinforcement, and the lower end reinforcement and the lower part of the lattice reinforcement are embedded in the concrete plate body. It is characterized by the following.

In the case of the present invention, the reinforcing member of the truss structure is constituted by combining a steel frame having a vertical rib on the lower surface of the horizontal plate portion with the lower end reinforcing bar and the lattice bar, thereby forming a bending rigidity of the precast concrete plate. And it can be used for long span buildings without the need for support. In addition, by changing the welding position of the lattice bar to the vertical ribs up and down, the overall height of the reinforcing body can be changed without changing the height of the lattice bar itself, and when forming concrete plates of various thicknesses The versatility of the lattice muscle is increased. Further, since the upper surface of the upper end steel frame of the reinforcing member is formed flat by the horizontal plate portion, it is easy to arrange and weld the reinforcing bar on the reinforcing member.

According to a second aspect of the present invention, in the precast concrete slab according to the first aspect, the reinforcing member of the truss structure has a cross section T having a longitudinal rib extending in a longitudinal direction on a lower surface of the horizontal plate portion. And a top-shaped steel frame
Two lower reinforcing bars which are arranged below and spaced apart from each other below the upper steel frame and extend in the same direction as the upper steel frame; and the upper steel bar and the lower reinforcing bars provided on both sides of the vertical ribs of the upper steel frame, respectively. Are formed in a zigzag manner so as to connect them alternately and extend in the same direction.

In the case of the present invention, since the reinforcing member of the truss structure has a pair of lower reinforcing bars and a pair of lattice bars,
This is advantageous for improving the strength, and since the upper end steel frame is formed in a T-shaped cross section, both side portions of the vertical rib can be used for bonding to the lattice.

According to a third aspect of the present invention, in the precast concrete slab according to the first or second aspect, both ends of the upper end steel frame project outward beyond the concrete slab main body. The part is formed in a bridging part that bridges a beam of the building.

In the case of the present invention, the concrete plate body can be provided between the opposing beams so as not to protrude above the beams by bridging the projecting portions at both ends of the upper end steel frame. It is advantageous in suppressing, and it is only necessary to make the above upper steel frame longer than the concrete slab main body, and it is necessary to separately add a dedicated member for the erection and to separately reinforce the end of the concrete slab main body Is not required.

According to a fourth aspect of the present invention, in the precast concrete slab according to any one of the first to third aspects, a cast-in-place concrete formed by reinforcing a reinforcing bar on the upper surface of the horizontal plate portion of the upper end steel frame. The reinforcing mesh is welded.

In the present invention, a reinforcing mesh is preliminarily welded to a truss structure reinforcing body by utilizing the fact that the upper surface of the horizontal plate portion is flat and the reinforcing bar is easily welded. In the present invention, since the mounting strength or the mounting stability of the reinforcing mesh can be increased, the reinforcing mesh can be prevented from coming off during transportation or erection of the precast concrete slab, and moreover, on site. Work becomes easier.

According to a fifth aspect of the present invention, there is provided a precast concrete plate in which a lower portion of a truss structure reinforcing member is embedded in a concrete plate main body.
An upper end member and a lower end member extending in the same direction at an interval above and below each other, and a lattice staggered in a zigzag manner to alternately connect the upper end member and the lower end member and extending in the same direction as these members are provided. The lower end member and the lower part of the lattice streak are buried in the concrete slab main body, and both ends of the upper end member project outward of the concrete slab main body, and both end protruding portions of the upper end member of the precast concrete slab are provided. Are laid on the upper surface of the opposing beam, and cast-in-place concrete is cast on the concrete slab body so as to surround the truss structure reinforcing body.

In the present invention, the projecting portions at both ends of the upper end member constituting the truss structure reinforcing member are mounted on the opposing beams, so that the concrete slab main body is disposed between the opposing beams to suppress the floor height. In addition, it is not necessary to add a dedicated member for erection and reinforcement for that purpose. As the upper end member, it is preferable to use a steel frame having a vertical rib which is a characteristic configuration of the invention described above, but other steel materials may be used.

[0018]

Therefore, according to the invention of this application, the upper end member of the truss structure reinforcement whose lower portion is buried in the concrete plate body is constituted by the upper end steel frame having the vertical ribs provided on the lower surface of the horizontal plate portion. As a result, the bending rigidity of the precast concrete slab is increased, and even if the precast concrete slab is used for long spans, there is no need for supports or small beams, which is advantageous for cost reduction, shortening the construction period, and improving on-site workability. become. Moreover, since it is possible to change the overall height of the reinforcing member without changing the height of the lattice streaks, it is possible to obtain a precast concrete slab having a different standard while suppressing costs, and furthermore, on the truss structure reinforcing member. It is also easy to add reinforcing bars and other reinforcing members.

Further, according to the invention relating to a precast concrete plate in which both ends of the upper end steel frame are projected outward from the concrete slab main body so as to hang the opposite beams, or the upper end member of the precast concrete plate According to the floor slab structure in which the projecting portions at both ends are laid on the upper surfaces of the opposing beams, the floor height can be kept low without adding a dedicated erection member or reinforcing the concrete slab main body.

Further, according to the invention of the precast concrete plate in which the reinforcing mesh is welded to the upper surface of the horizontal plate portion of the upper end steel frame, the reinforcing mesh comes off during transportation or erection of the precast concrete plate. While simplifying field work.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a precast concrete slab 1 according to the present invention. In this precast concrete slab 1, reference numeral 2 is a concrete slab main body, 3 is a truss structure reinforcing body, 4 is a mesh for reinforcing cast-in-place concrete, and is welded to the upper surface of the truss structure reinforcing body 3. Reference numeral 5 denotes an embedding material fixed on the upper surface of the concrete slab main body 2. In this embodiment, four truss structure reinforcements 3 are provided at right and left intervals, and the lower part of each reinforcement 3 is embedded in the concrete slab main body 2, and the upper part thereof is above the upper surface of the concrete slab main body 2. Projecting to The reinforcing mesh 4 is formed by arranging rebars vertically and horizontally and welding them to form a lattice, and may be welded to the truss structure reinforcing body 3 at a construction site. The embedding material 5 is made of polystyrene foam, and a plurality of embedding materials 5 are provided between adjacent truss structural reinforcements 3 at intervals in the longitudinal direction. In some cases, the embedding material 5 is not provided.

As shown in FIG. 2, the truss structure reinforcing member 3 has a single upper steel frame 6 and is disposed below the upper steel frame 6 with a space left and right and extends in the same direction as the upper steel frame 6.
The lower end reinforcing bars 7, 7 of the book, the upper end steel frame 6, and the lower end reinforcing bars 7,
7 and two lattice muscles 8, 8. The upper end steel frame 6 has a T-shaped cross section in which a vertical rib 6b is provided at the center of the lower surface of a long horizontal plate portion 6a having a horizontal plate surface. For example, H
A CT section steel obtained by cutting a section steel at the center of the web can be used. The lattice bars 8, 8 are provided on both sides of the vertical ribs 6b of the upper end steel frame 6, and are bent in a zigzag manner so as to alternately connect the upper end steel frame 6 and the lower end reinforcing bars 7, 7 to form a longitudinal portion of the upper end steel frame 6. Extending in the direction. In this example, the bent portion of the lattice stitch 8 is applied to the horizontal plate portion 6a of the upper end steel frame 6 and is welded to a corner formed by the horizontal plate portion 6a and the vertical rib 6b, but is appropriately separated from the horizontal plate portion 6a. In some cases, welding is performed on the side surface of the vertical rib 6b.

As shown in FIG. 3, in the concrete slab main body 2 of the precast concrete slab 1, a reinforcing mesh 9 formed by arranging reinforcing bars vertically and horizontally and welding them in a lattice shape is laid horizontally. Have been. The truss structure reinforcing member 3 has reinforcing meshes 7 at its lower ends.
And is embedded in the concrete slab body 2,
Lattice streaks 8, 8 have lower portions embedded in concrete slab body 2 and upper portions project together with upper end steel frame 6 above concrete slab body 2.

FIG. 4 shows the precast concrete slab 1 described above.
Shows a state in which the floor is erected as a floor slab on the beam 11 of the building. In the figure, reference numeral 12 denotes a pillar. As shown in FIG. 5, the precast concrete slab 1 has
Are projecting outward from the end surface of the concrete slab main body 2, and the two projections 13, 13 are opposed to each other.
1,11. FIG. 6 is a view (partially omitted) as viewed from an arrow A in FIG. As shown in FIG. 5, a reinforcing bar 4a of the cast-in-place concrete reinforcing mesh 4 extending in the same direction as the truss structure reinforcing member 3 has one end bent vertically downward and the other end formed of a straight bar. Has been left.

Cast-in-place concrete is shown in FIG.
As shown in the figure, it is cast on the concrete slab body 2 and over the beam 11 so as to wrap the truss structure reinforcing member 3 and the reinforcing mesh 4. Although not shown, the concrete plate body 2 and the upper end steel frame 6 are not shown.
Between them, facilities such as electric wiring and piping are provided, and cast-in-place concrete 14 is cast after the facilities.

Therefore, in such a floor slab structure, the portion of the precast concrete slab 1 below the upper end steel frame 6 is disposed between the opposing beams 11, 11.
Of the resulting slab, only about the upper half of the thickness of the floor slab comes out above the beam 11. Therefore, it is not necessary to secure a thick space between the upper floor and the lower floor, and the floor height can be suppressed.

Such a floor slab structure can be adopted because both ends of the upper end steel frame 6 of the truss structure reinforcing member 3 have protrusions 13, 13 protruding outward from the concrete slab main body 2.
Is provided so that it can be hung on the beam 11.
Since the projecting portion 13 is constituted by a part of the upper end steel frame 6 having a high strength and a T-shaped cross section, it is not necessary to separately provide a dedicated member for erection, and the concrete plate main body 2 is not required.
There is no need to separately reinforce the end of the.

The upper end steel frame 6 has high strength (high bending rigidity) because it has the vertical ribs 6b. Therefore, the precast concrete slab 1 itself also has high bending rigidity. Even if the beams 11 have a long span, they can be bridged without any support work, which is advantageous for workability, shortening the construction period, and reducing costs.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a precast concrete slab according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a part of the truss structure reinforcement of the concrete slab.

FIG. 3 is a sectional view showing a part of the concrete slab.

FIG. 4 is a front view showing a state where the concrete slab is stretched over beams of a building.

FIG. 5 is an enlarged front view of the same state with a part thereof omitted;

FIG. 6 is a view taken in the direction of arrow A in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Precast concrete plate 2 Concrete plate main body 3 Truss structure reinforcement 4 Cast-in-place concrete reinforcement mesh 5 Embedding material 6 Upper steel frame 6a Horizontal plate portion 6b Vertical rib 7 Lower reinforcement 8 Lattice reinforcement 9 Body reinforcement mesh 11 Beam 12 Column 13 Projecting part (hanging part) 14 Cast-in-place concrete

Claims (5)

[Claims] 1. A precast concrete slab comprising a concrete slab main body, and a truss structure reinforcement having a lower part embedded in the concrete slab main body and an upper part protruding from an upper surface of the concrete slab main body, wherein the truss structure is provided. A reinforcing member having a longitudinal rib extending in the longitudinal direction on the lower surface of the horizontal plate portion; a lower reinforcing bar disposed below the upper steel frame and extending in the same direction as the upper steel frame; A precast, comprising: a lattice bar bent in a zigzag manner and alternately extending in the same direction so as to alternately tie the reinforcing bar, and the lower end reinforcing bar and a lower portion of the lattice bar are embedded in the concrete plate body. Concrete version. 2. The precast concrete slab according to claim 1, wherein the reinforcing member of the truss structure has a T-shaped upper end steel frame having a longitudinal rib extending in a longitudinal direction on a lower surface of a horizontal plate portion. Two lower reinforcing bars which are arranged below the upper steel frame at an interval on the left and right and extend in the same direction as the upper steel frame, and the upper steel bar and the lower reinforcing bars provided on both sides of the vertical rib of the upper steel frame, respectively. And a pair of lattice bars which are bent in a zigzag and extend in the same direction so as to alternately connect with the precast concrete plate. 3. The precast concrete slab according to claim 1, wherein both ends of the upper end steel frame project outward from the concrete slab main body, and the projecting portion is a beam of a building. A precast concrete slab characterized in that it is formed in a bridging portion for bridging. 4. The precast concrete slab according to any one of claims 1 to 3, wherein a cast-in-place concrete reinforcing mesh formed by reinforcing steel is welded to an upper surface of the horizontal plate portion of the upper end steel frame. A precast concrete slab characterized by the fact that: 5. A precast concrete slab in which a lower portion of a truss structure reinforcing member is embedded in a concrete plate body, wherein the truss structure reinforcing member has an upper end member and a lower end member extending in the same direction at an interval vertically above and below each other. A lattice bar that bends in a zigzag manner to alternately connect the upper end member and the lower end member and extends in the same direction as these members, and a lower portion of the lower end member and a lattice bar is embedded in the concrete plate body. And both ends of the upper end member protrude outward from the concrete slab main body, and both end protruding portions of the upper end member of the precast concrete slab are hung on the upper surface of the opposing beam, and are placed on the concrete slab main body. A floor slab structure for a building, wherein cast-in-place concrete is cast so as to surround the truss structure reinforcement.