JPH0790814A - Binding structure of precast floor slab - Google Patents

Abstract

PURPOSE:To simplify mutual binding work of floor slabs adjacent to each other concerning the reinforced concrete made precast floor slabs on a steel girder road bridge. CONSTITUTION:In the state where a floor slab 1B is inclined against a previously set floor slab 1A set on a steel girder, by revolving the floor slab 1B clockwise after inserting a shear key into bound parts 10, 10 formed in respective end parts of respective upper step side reinforcing bars 2A, 2B of both of the floor slabs 1A, 1B, bound parts 10C, 10D formed on respective end parts of respective lower step side reinforcing bars 22A, 22B are superposed. By inserting the shear key into their circular holes 9a, a fulcrum metal fitting 12 is compressed, tensile force is generated on each of the reinforcing bars by its reaction force, and the floor slabs 1A, 1B are made to compress them. Consequently, it is possible to apply prestress and to simplify binding work of the floor slabs 1A, 1B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced concrete precast floor slab used for a steel girder road bridge, and more particularly to a joint portion for joining adjacent precast slabs of a precast slab disposed on a steel girder. Regarding

[0002]

2. Description of the Related Art Generally, at a steel girder road construction site, a large number of rectangular parallelepiped precast floor slabs manufactured at a factory are installed at predetermined intervals on a steel girder at a construction site so that they can be transported. The work of joining adjacent precast floor slabs is being carried out. And this connection is made as follows. That is, as shown in FIG. 6, precast floor slabs 1 and 1 are installed adjacently on a steel girder (not shown) at a predetermined interval so that the required lap joint length of the reinforcing bar 2 can be obtained, and After the streaks 3 and the form 4 are applied, concrete 5 is cast on site to join the precast floor slabs 1 and 1 in the gap formed between the precast floor slabs 1 and 1.
After the concrete is hardened, the PC steel wire 7 is passed through the sheath 6 installed in the precast floor slab 1 in advance, and tension is applied to the precast floor slab by tensioning the PC steel wire 7.

[0003]

By the way, the connection of the conventional precast floor slab as described above has the following problems. (1) Formwork / reinforcing is performed on site and concrete is placed, so the site is easily soiled and the construction period is long. (2) Since prestress is introduced after installing all floor slabs, it takes a long construction period and is uneconomical. (3) During replacement work due to partial damage to the floor slab, demolition of concrete involves lifting work, which causes dust generation, and the construction period is long, which is uneconomical. SUMMARY OF THE INVENTION It is an object of the present invention to provide a precast floor slab having a connecting structure that allows the precast floor slabs arranged adjacent to each other to be connected by a simple operation.

[0004]

In order to achieve the above-mentioned object, the connecting structure of the precast floor slab of the present invention is formed into a substantially rectangular parallelepiped overall shape, and the upper side and the lower side respectively have upper steps. In the connection structure between the precast floor slabs formed so that the reinforcing bars and the lower-stage side reinforcing bars are inserted and the exposed end portions of the reinforcing bars are formed on the connecting end surfaces at both ends of the rectangular parallelepiped, the intermediate portions of the connecting end surfaces facing each other. Since a fulcrum metal fitting is inserted in and a horizontal shear key is provided to connect the exposed portions of the reinforcing bars facing each other, prestress is applied to the precast floor slab as a reaction force of the tensile force applied to each reinforcing bar. It is characterized by being combined like this.

[0005]

In the above-described precast floor slab connection structure of the present invention, since the precast floor slabs installed adjacent to each other are directly mechanically connected to each other by their reinforcing bars, there is no fear of reduction in strength during the connection. In addition, since the fulcrum metal fittings are interposed between the floor slabs when the reinforcing bars of the adjacent precast slabs are connected, the precast slabs can be automatically prestressed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The connecting structure of a precast floor slab as an embodiment of the present invention will be described below with reference to the drawings.
3 is a side sectional view thereof, FIG. 2 is a side sectional view showing a coupling procedure, and FIG.
3 is a side view of the connecting portion, FIG. 4 is a view taken in the direction of arrow A in FIG. 3, and FIG.
FIG. 1 to 5, the same reference numerals as those in FIG. 6 indicate almost the same members.

In this embodiment also, the precast floor slabs 1A, 1
B are installed adjacent to each other on a steel girder to form a steel girder road bridge, and in FIG. 1, reference numerals 1A and 1B indicate that the overall shape is a substantially rectangular parallelepiped and both side surfaces thereof are connected end faces. The precast floor slabs formed in X and Y are shown. Both precast floor slabs 1A and 1B are formed to have substantially the same structure except for a fulcrum fitting 12 and the like described later. A precast floor slab 1B is installed adjacent to the right side of 1A. Precast floor slab 1A
A fulcrum support plate 14 is embedded and attached to the connection end surface X on the right side of the sill by a dowel 16a, and a fulcrum metal fitting 12 made of a material having high rigidity such as a steel rod is attached to the surface of the fulcrum support plate 14 on the precast floor slab 1A.
Is projected and welded from the right end face.

On the other hand, a pressure receiving plate 15 is attached to the left connecting end surface Y of the precast floor slab 1B so as to be opposed to the fulcrum support plate 14 by embedding by a dowel 16b. The pressure receiving plate 15 is formed with a recessed portion 15a having an angle θ required to secure a relative position with the fulcrum metal fitting 12. In addition, the precast floor slabs 1A and 1B include the precast floor slabs 1A and 1B.
In order to apply pre-stress to the upper part and the lower part, upper and lower reinforcing bars 2A, 2B, 22A and 22B are inserted through a sheath (not shown). And 2A, 2B, 22A, 22B of each rebar is penetrated through all precast floor slabs 1A, 1B, and each rebar 2
A coupling portion 10 is formed at each end exposed on each connection end face X, Y of A, 2B.

As shown in FIGS. 3 to 5, the connecting portion 10 is formed at the right end portion of the reinforcing bar 2A (22A) and has a circular hole 9a in the central portion and a convex portion having a circular outer shape. 9 and a concave portion 8 which is provided in parallel in the left-right direction of the convex portion 9 and has an arcuate sliding surface 8a having the same inner diameter as the circular outer peripheral surface 9b of the convex portion 9 and the outer shape of which is formed in a substantially semicircular shape. It is configured. The joints 10 at the left ends of the upper and lower rebars 2B, 22B of the precast floor slab 1B are symmetrical to this, and the joints on the side of the precast floor slab 1A and the precast floor slab 1B.
When the coupling portion on the side is coupled, the convex portion 9 and the concave portion 8 of both coupling portions 10 mesh with each other and the outer peripheral surface 9b of one convex portion 9 slides on the sliding surface 8a of the other concave portion 8. I have come into contact with them.

When the connecting portions 10 and 10 are overlapped in the left and right direction, the circular holes 9a and 9a are aligned on the same horizontal line, and the shear key 1
By inserting 1 horizontally, both joints 10, 10
Are combined. Also, precast floor slabs 1A, 1
Oblique cut portions 17A and 17B are formed on the upper and lower ends of B, respectively, to facilitate the connecting work described later. With the above configuration, the precast floor slabs 1A and 1B are joined together as follows.
The procedure is as follows.

That is, as shown in FIG. 2, the precast floor slab 1 on the mounting side with respect to the existing precast floor slab 1A.
With B slanted, the connecting portion 10A of the rebar 2A on the upper side of the precast floor slab 1A (auxiliary symbols "A", "B" ...
Etc. to distinguish from other joints, the same applies hereinafter) and the joints 10B of the rebar 2B on the upper side of the precast floor slab 1B are polymerized in the left-right direction (direction perpendicular to the paper surface in FIG. 2), and The shear key 11 is inserted horizontally into the circular hole 9a. Next, precast floor slab 1B centered on shear key 11
Is rotated clockwise until the connecting portions 10C, 10D of the lower reinforcing bars 22A, 22B of both precast floor slabs 1A, 1B reach the position where the connecting portions 10C, 10D overlap in the left-right direction (the state of FIG. 1).

Then, the shear key 11 is horizontally inserted into the circular holes 9a of the coupling portions 10C and 10D. This allows
The fulcrum bracket 12 receives a compressive force from both sides, and as a reaction force, a tensile force is generated on both the upper rebars 2A and 2B and the lower rebars 2C and 2D of both precast floor slabs 1A and 1B. To do. In this way, the connecting portion 10A-
When 10D is bonded, it is possible at the same time to apply a prestress to both precast floor slabs 1A and 1B so as to compress them. The prestressing amount in this case is adjusted by adjusting the position and size of the fulcrum bracket 12 and the rotation amount of the precast floor slab 1B.
It can be set to a predetermined value.

After the joining of the joining portions of both precast floor slabs 1A, 1B is completed, the upper diagonal cut portions 17A, 17B are formed.
A compression block 13 is inserted between them, and both precast floor slabs 1
The joining work of A and 1B is completed. The compression block 13 is inserted in order to make the top surface of the floor slab smooth and to be integrated with the precast floor slab so that the compression force is directly transmitted between the adjacent precast floor slabs. No claws are placed between the lower diagonal cuts 17A and 17B.

Thus, in this embodiment, the connecting portion is
10, the convex portion 9 having the circular hole 9a and the concave portion 8 are formed side by side, and the adjacent coupling portions are superposed so that the concave portion 8 and the convex portion 9 can mesh with each other. Since the shear key 11 is horizontally inserted through the aligned circular hole 9a, a tensile force is applied to the reinforcing bar through the shear key 11 to pre-cast floor slabs 1A, 1
B can be prestressed to compress them. Further, the meshing force between the concave portion 8 and the convex portion 9 can transmit the shearing force. In addition, the precast floor slab can be replaced by simply attaching and detaching the shear key 11, which is advantageous in terms of repair cost.

[0015]

As described in detail above, according to the joining structure of the precast floor slab of the present invention, the following effects and advantages can be obtained. (1) The concrete work associated with the connection at the site disappeared,
It can provide a clean site and contribute to cost reduction and shortening of construction period. (2) Since prestress is introduced every time one precast slab is installed, it can contribute to shortening the construction period. (3) The floor slab can be replaced by simply attaching and detaching the shear key, eliminating the problem of dust generation and reducing the cost for repairs.
It can contribute to shortening the construction period.

[Brief description of drawings]

FIG. 1 is a side sectional view of a joint structure of a precast floor slab according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the connecting procedure.

FIG. 3 is a side view of the connecting portion.

FIG. 4 is a view on arrow A of FIG.

5 is a view on arrow B of FIG.

FIG. 6 is a side view of a conventional procedure for joining precast floor slabs.

[Explanation of symbols]

 1A, 1B Precast floor slab 2A, 2B Upper-stage reinforcing bar 3 Distribution bar 8 Concave 8a Sliding surface 9 Convex part 9a Circular hole 9b Outer peripheral surface 10 Joint part 11 Shear key 12 Support point metal fitting 13 Compression block 14 Support point support plate 15 Pressure receiving plate 16a, 16b Gibel 22A, 22B Lower end rebar X, Y connection end face

Claims (1)

[Claims] 1. The overall shape is formed into a substantially rectangular parallelepiped, and upper and lower rebars are inserted through the upper part and the lower part, respectively, and exposed parts of the rebars are formed on connection end faces at both ends of the rectangular parallelepiped. In the connection structure between the precast floor slabs formed to have, while the fulcrum metal fitting is interposed in the intermediate portion of the connection end surface facing each other,
By providing horizontal shear keys for connecting the exposed portions of the reinforcing bars facing each other, the precast floor slabs are coupled so as to be prestressed as a reaction force of the tensile force applied to the reinforcing bars. The combined structure of precast floor slabs.