JP4565332B2 - Stepped slab and its construction method - Google Patents

Description

  The present invention relates to a stepped slab and a construction method thereof.

Conventionally, a slab with a step is formed by placing a reinforcing bar with a hook on the step portion of two perforated precast concrete plates provided with a step in the vertical direction, and then placing on-site cast concrete on the step portion. ing. That is, the step portion was formed by on-site construction. However, in the conventional stepped slab, the bar arrangement of the stepped portion is complicated, and it takes time for construction.
In view of this, the present inventor has devised a slab with a step in Patent Document 1 by using a reinforcing bar with a fixing head at the stepped portion, thereby providing a simple bar arrangement structure and good workability and shortening the work period.
JP 2002-294916 A (page 2-3, FIG. 1-3)

  However, the stepped slab described in Patent Document 1 also requires formwork for forming the stepped portion, like the conventional stepped slab.

  The present invention further improves the slab with a step described in Patent Document 1, provides a slab with a step that can greatly eliminate the formwork, and can ensure high construction accuracy, and a construction method thereof. Objective.

In order to achieve the above object, the stepped slab according to the present invention includes a pair of hollow precast concrete plates each having a fixing head-attached reinforcing bar disposed at one end thereof, and the ends thereof are overlapped in the vertical direction. A step portion is formed.
Here, the reinforcing bar with the fixing head is a reinforcing bar in which a diameter-expanded portion is formed at an end in order to increase the fixing strength of the reinforcing bar.
In the present invention, the stepped portion is formed by overlapping the ends of a pair of hollow precast concrete plates each having a fixing head-attached reinforcing bar at one end in the vertical direction. Construction and formwork will be greatly omitted, and construction will be made more efficient. In addition, along with the decrease in bar arrangement work and formwork, it is possible to ensure high construction accuracy.

Moreover, in the stepped slab according to the present invention, the reinforcing head-attached reinforcing bars on the upper side and the lower side of the stepped portion are constrained by shear reinforcement bars .
In the present invention, since the reinforcing bars with fixing heads on the upper side and the lower side in the stepped portion are restrained by the shear reinforcing bars, the strength of the stepped portion can be increased.

Moreover, the construction method of the stepped slab according to the present invention is a method in which the end portions of the pair of hollow precast concrete plates are overlapped in the vertical direction to form a stepped portion having hollow portions arranged in two upper and lower stages, A first step of providing a slit portion communicating with the hollow portion in the vertical direction in the stepped portion; a reinforcing bar with a fixing head is inserted into each hollow portion; A second step of filling the slit portion with a filler after being disposed on the step, and a third step of placing the concrete on the pair of hollow precast concrete plates and placing the concrete. And
In the present invention, a slit portion that communicates the upper and lower two-stage hollow portions disposed in the stepped portion is provided, and the fixing head-attached reinforcing bars are disposed in the upper and lower two steps in the slit portion so that the filler is filled. Construction work is greatly streamlined, and the construction period and cost can be reduced.

  Moreover, in the construction method of the stepped slab according to the present invention, in the second step, the upper-stage side and lower-stage side reinforcing bars may be restrained by shear reinforcement bars.

  In the present invention, the stepped portion is formed by overlapping the ends of a pair of hollow precast concrete plates each having a fixing head-attached reinforcing bar at one end in the vertical direction. Construction and formwork can be greatly omitted, and construction efficiency can be improved. In addition, along with the decrease in bar arrangement work and formwork, it is possible to ensure high construction accuracy.

Hereinafter, the stepped slab according to the present invention will be described with reference to the drawings.
1A is a side cross-sectional view of a stepped slab according to the present invention, and FIG. 1B is a cross-sectional view taken along line AA in FIG.
The stepped slab according to the present invention forms a stepped portion 1 by overlapping the ends of a pair of hollow precast concrete plates (hereinafter referred to as hollow PC plates) 2 and 3 in the vertical direction to form a hollow PC plate 2. 3, the slab reinforcement 11 is arranged, and the upper end reinforcement 9 is arranged on the step portion 1, and the concrete 10 is placed.

  The hollow PC plates 2 and 3 are formed by a plurality of hollow portions 2a and 3a having a cross section such as a sector or an ellipse in the PC plate. It extends and is arranged side by side in the short side direction. A PC steel wire 15 is disposed between the hollow portions 2a and 3a and the hollow portions 2a and 3a. Therefore, it has the features of light weight, high strength, and high durability.

The hollow portion 2a formed in the upper hollow PC plate 2 and the hollow portion 3a formed in the lower hollow PC plate 3 are arranged in a vertically aligned state. In the step portion 1, the hollow portion 2a 3a is formed in the up-down direction, and a slit portion 4 is formed to open upward.
Reinforcing bars 5 with fixing heads having enlarged diameter portions at both ends are inserted into the hollow portions 2a and 3a at the ends (stepped portion 1 side) of the hollow PC plates 2 and 3, respectively. The provided reinforcing bars 5 and 5 with the fixing head are restrained by the shear reinforcing bar 7 in the slit portion 4.
In addition, a U-shaped stirrup 6 wound around the upper end bars 9, 9 arranged in the short side direction of the hollow PC plates 2, 3 in the stepped portion 1 is connected to the lower reinforcing bar 5 with the fixing head. Yes. In the stepped slab according to the present invention, the lower end bars of the stepped portion 1 are omitted, and the stress is processed by the reinforcing head-attached reinforcing bars 5.
In addition, the reinforcing head-attached reinforcing bar 5, the shear reinforcing bar 7, and the ribbed bar 6 are disposed in the hollow portions 2a and 3a.

Part of the slit portion 4 and the hollow portions 2a and 3a (portions where the reinforcing bar 5 with the fixing head is disposed) is filled with a filler such as mortar. At this time, a partition plate 12 is installed in the hollow portions 2a and 3a so that the filler does not flow into the hollow portions 2a and 3a.
Further, a gap D of about 10 to 20 mm is provided between the upper hollow PC board 2 and the lower hollow PC board 3, and the gap D is filled with a filler, and the hollow PC board 2, The adhesiveness between the three is improved.

Here, the overlap length of the reinforcing head-attached rebars 5 and 5 arranged in two upper and lower stages, and the length obtained by subtracting the overlap length from the fixing head-attached rebar 5 (the length of the non-overlapping portion) are: the same length L _2, and more than 35 times the diameter of the fixing head with rebar 5. Moreover, the deformed reinforcing bar of D16-25 is used for the reinforcing bar 5 with a fixing head.

  The stepped portion 1 is provided with anchor bars 8 for the slab bars 11 arranged on the lower hollow PC plate 3, and the end surface of the upper hollow PC plate 2 (stepped portion 1 side). ) To the side.

Next, the construction method of the stepped slab according to the present invention will be described.
When constructing a stepped slab according to the present invention, a half-precast stepped slab manufactured in a factory is installed between beams, and a concrete is placed by placing a bar on it. It becomes.

FIG. 2 and FIG. 3 are diagrams for explaining a manufacturing procedure of a stepped slab in a factory.
First, the ends of the pair of hollow PC plates 2 and 3 so that the hollow portion 2a formed in the upper hollow PC plate 2 and the hollow portion 3a formed in the lower hollow PC plate 3 are aligned vertically. The step portions 1 are formed by overlapping the portions with a gap D of about 10 to 20 mm in the vertical direction (see FIG. 2).
Then, the end portions of the hollow PC plates 2 and 3 are partially cut, the hollow portions 2a and 3a disposed in the two upper and lower stages are communicated in the vertical direction, and the slit portion 4 that opens upward is the stepped portion 1 To form.
In addition, after forming the slit part 4 in the hollow PC board 2 on the upper stage side and the hollow PC board 3 on the lower stage side, the ends of the pair of hollow PC boards 2 and 3 may be overlapped in the vertical direction.

Next, rebars 5 and 5 with fixing heads are inserted into the hollow portions 2a and 3a, and the rebars 5 and 5 with fixing heads are arranged in the upper and lower two stages in the slits 4 so as to fix the upper and lower stages. The head-reinforcing bars 5 and 5 are constrained by the shear reinforcement bars 7, and the U-shaped ribbed bars 6 are connected to the lower fixing head-reinforcing bars 5.
In addition, a partition plate 12 is installed in the hollow portions 2a and 3a, and anchor bars 8 are disposed so as to protrude from the end surface (step portion 1 side) of the upper hollow PC plate 2.

  Next, after the molds 13 and 13 are attached to the end surfaces (stepped portion 1 side) of the upper hollow PC plate 2 and the lower hollow PC plate 3, respectively, the hollow portions 2a and 3a are sealed, and then the slit portion 4 In addition, a filler such as mortar is filled in a part of the hollow portions 2a and 3a in which the reinforcing bar 5 with the fixing head is arranged. At this time, the gap D is also filled with the filler.

FIG. 4 is a schematic view showing a state where a stepped slab is installed between beams, and FIG. 5 is a diagram for explaining a construction procedure of the stepped slab in the field.
The stepped slab S manufactured at the factory is carried into the construction site and is installed between the beams B and B. A notch Ba is formed at the top of the beam B, and the stepped slab S is placed on the notch Ba. Note that the stepped slab S may not be placed on the notch Ba, but may be supported by a support (not shown).

  Next, a single slab barb 11 is placed on the hollow PC plates 2 and 3, and an upper end bar 9 is arranged across the rib 6 on the stepped portion 1. And after installing the formwork 14 on the upper side surface of the stepped portion 1, the concrete 10 is placed on the hollow PC plates 2 and 3.

  In this embodiment, the end portions of the pair of hollow PC plates 2 and 3 are overlapped in the vertical direction to form the stepped portion 1, and the upper and lower two-step hollow portions 2 a and 3 a disposed on the stepped portion 1 are formed. Since the slit part 4 which communicates is provided, and the reinforcing bars 5 and 5 with fixing heads are arranged in the upper and lower stages in the slit part 4 and filled with the filler, the bar arrangement work and the formwork work are largely omitted. Can be made more efficient. In addition, along with the decrease in bar arrangement work and formwork, it is possible to ensure high construction accuracy.

As described above, the stepped slab according to the present invention has been described, but the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist thereof. It is only necessary to obtain the function.

(A) is a sectional side view of the stepped slab according to the present invention, and (b) is an AA arrow sectional view. It is a figure for demonstrating the manufacture procedure of the slab with a level | step difference in a factory, (a) is a sectional side view of a slab with a level | step difference, (b) is a BB arrow sectional drawing. It is a figure for demonstrating the manufacture procedure of the slab with a level | step difference in a factory, (a) is a sectional side view of a slab with a level | step difference, (b) is CC sectional view taken on the line. It is the schematic which shows the state which constructed the slab with a level | step difference between beams. It is a sectional side view of the stepped slab for explaining the construction procedure of the stepped slab at the site.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Step part 2, 3 Hollow PC board 2a, 3a Hollow part 4 Slit part 5 Reinforcing bar with fixing head 6 Stirrup 7 Shear reinforcement bar 8 Anchor bar 9 Top bar 10 Concrete 11 Slab bar 12 Partition plates 13 and 14 Form 15 PC steel wire D Gap B Beam Ba Notch S Slab with step

Claims (3)

A stepped portion is formed by overlapping the ends of a pair of hollow precast concrete plates each having a fixing head-attached reinforcing bar at one end in the vertical direction ,
A stepped slab, wherein the reinforcing bar with fixing head on the upper side and the lower side of the stepped portion is constrained by a shear reinforcing bar. The ends of the pair of hollow precast concrete plates are overlapped in the vertical direction to form a stepped portion having a hollow portion arranged in two upper and lower steps, and the slit portion communicating the hollow portion in the vertical direction is the step A first step provided in the section;
A second step of inserting a reinforcing head-attached reinforcing bar into each of the hollow parts, and arranging the fixing head-attached reinforcing bar in the upper and lower stages in the slit part, and then filling the slit part with a filler;
And a third step of placing the concrete on the pair of hollow precast concrete plates and placing the concrete thereon. In the second step,
3. The method for constructing a slab with a step according to claim 2 , wherein the reinforcing head-attached reinforcing bars on the upper side and the lower side are restrained by a shear reinforcing bar.

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