JPH06299514A - Reinforced concrete buried formwork - Google Patents

Abstract

(57) [Summary] [Purpose] Reinforcement work in a narrow space is reduced to reduce formwork. [Structure] Reinforced concrete buried formwork with reinforcing bars protruding in four directions

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced concrete buried formwork suitable for use in a narrow space where workability of formwork is poor.

[0002]

2. Description of the Related Art A formwork method for placing concrete with box-shaped cross-section girders, such as that found in many prestressed concrete cable-stayed bridges, is as follows: A method of connecting the frames with a foam tie or a separator, or a method of additionally providing a supporting material in the space section of the box-shaped cross section is generally used.

[0003]

[Problems to be Solved by the Invention] The main girder (box-shaped girder) of a prestressed concrete cable-stayed bridge is constructed so that the force exerted by its own weight acting on the main girder or the load on the vehicle is transmitted to the cable diagonally. A cross girder in the direction perpendicular to the bridge axis is provided at the portion connected to the material cable. Therefore, in the box-shaped cross-section girder, after the completion not only in the lateral direction but also in the longitudinal direction, the manhole remains and becomes almost a closed space. For this reason,
The workability inside the narrow box-shaped cross girder, especially the formwork, was poor. In addition, before constructing the cross girder, the formwork is demolded and moved to the outside of the planned girder, or many small formworks are used to transfer through the manhole after the girder construction. Took time and effort.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to reduce the work of formwork in such a narrow space, and is to arrange some or all of the reinforcing bars of members on site. And the function of the stopped reinforcing bar is taken over by the reinforcing bar embedded in the ready-made reinforced concrete embedded formwork manufactured in a place with a good working environment, and the embedded formwork and the main concrete to be placed later. In order to ensure the integrity of the above, the reinforcing bar is projected in four directions of the embedded formwork, and is preferably bent to the concrete side of the main body.

Reinforcing bars protruding in four directions of the embedded formwork and preferably bent toward the main body concrete side contribute to the integration of the embedded formwork and the main body concrete, and at locations where structural members are adjacent or intersect. In the above, it contributes to connecting and integrating members.

The reinforced concrete buried formwork of the present invention is manufactured in the same manner as a concrete factory product is manufactured in a place having a good working environment such as a concrete product factory. At this time, reinforcing bars of the same or larger amount than the reinforcing bars required to reinforce the main body concrete are arranged vertically and horizontally, the tips of the reinforcing bars project from the concrete in four directions, and the projecting parts use embedded formwork. Depending on the location, it is processed into a length and shape that sufficiently encloses the adjacent area and the crossing area of the structural member. In addition, through holes for foam ties are also provided. Concrete is cast into the reinforced concrete embedded formwork for producing a formwork to manufacture a reinforced concrete embedded formwork in which the reinforcing bars project like whiskers around the panel surface. At the time of this production, the concrete surface of the inner surface of the embedded formwork ensures integration with the main body concrete,
It is preferably roughened.

The reinforced concrete buried formwork manufactured as described above is transported to the site, and in a predetermined position, the rough surface side is the main body concrete side, and the protruding rebars are in a direction to sufficiently enclose the intersection area of the structural members. , Is installed in the same manner as a normal diversion formwork. The projecting reinforcing bar is connected to the reinforcing bar of the other crossing structural member through a joint, and both members are integrated.

By using the reinforced concrete buried formwork of the present invention, not only the reinforcing bar of the member on the site is unnecessary, but also the process of removing, transferring and cleaning the formwork can be omitted.

In the above description, the box-shaped cross-section girder is cited as the place of use of the reinforced concrete buried formwork of the present invention, but this is an example, and the reinforced concrete buried formwork of the present invention is used in other places as well. Of course it will be done.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the buried formwork of the present invention.
(A) is an elevation view and (b) is a side view.

Reinforcing bars project from the rectangular reinforced concrete buried formwork 1 in all directions, and these projecting reinforcing bars 2 are bent approximately 90 ° toward the concrete side of the main body. The main body concrete side of the reinforced concrete panel 1 is roughened. The number and position of the protruding reinforcing bars 2 are determined in consideration of the weight and shape of the concrete body.

The form of use of the buried formwork of the present invention will be described by taking the above box-shaped cross-section girder as an example.

FIG. 2 (a) is a cut perspective view of a box-shaped cross-section girder, and FIG. 2 (b) is a vertical cross-sectional view around the inner web. The box-shaped cross-section girder of this example comprises an upper floor slab 3, a lower floor slab 4, an outer web 6, front and rear cross girders 7 and an inner web 5.

A case where the embedded formwork of the present invention is used as the formwork of the inner web 5 and the upper floor slab 3 will be described. Figure 2
As shown in (b), the embedded molds 1 and 1 are arranged on the respective surfaces to be the inner webs 5, and are connected by foam ties or separators. Then, the buried molds 1 and 1 for the upper floor slab 3 and the diversion molds 9 and 9 for the lower floor slab 4 are arranged at predetermined positions, and the diversion molds 9 and 9 for the lower floor slab 4 are placed in the lower part. Reinforcement reinforcement (not shown) for floor slab 4 is arranged. In addition, the inner web 5
The gap between the intersecting portion of the embedded formwork and the embedded formwork for the upper floor slab 3 is closed by the transfer formwork 9, 9. In this way, the entire formwork is assembled, and the main body concrete is placed from above. At the time of assembling this formwork, the protruding reinforcing bars 2 are connected and integrated with the reinforcing bars 10 of adjacent or intersecting structural members via a joint. FIG. 3 shows an example of the joint. (A) is a lap joint utilizing adhesion of concrete on the main body or a lap joint in which reinforcing bars are welded to each other, and (b) is a joint which mechanically connects the reinforcing bars with a coupler or a sleeve. Furthermore, since the projecting rebar 2 is bent inside the buried formwork 1, the integration of the buried formwork concrete with the main body concrete becomes more reliable.

The buried formwork of the present invention is usually used once for each block of the main body concrete that is cast. For example, when used on a web surface, the upper protruding rebars 2 are connected to the upper floor slab 3, the lower protruding rebars 2 are connected to the lower floor slab 4, and the lateral protruding rebars 2 are the front and rear crossbeams 7, Connect to 7.

However, the construction may become large, and the length of one block may not be enough with one embedded formwork. In such a case, a plurality of unit buried molds having the same structure as the buried mold of the present invention may be connected and used as a single buried mold as a whole. At this time, the protruding rebars 2 of the unit-embedded formwork are directly connected to each other via a mechanical joint, or the protruding rebars 2 are connected to each other as shown in FIG. In this case, it is necessary to block the gap of the connecting portion with a diversion frame.

[0018]

EFFECTS OF THE INVENTION By using the reinforced concrete buried formwork of the present invention, not only the reinforcing bar of the member on the site becomes unnecessary, but also the process of removing, transferring and cleaning the formwork can be omitted. it can.

[Brief description of drawings]

FIG. 1 shows an example of a buried formwork of the present invention, (a) is an elevation view and (b) is a side view.

FIG. 2A is a cutaway perspective view of a box-shaped cross section girder,
(B) is a vertical cross-sectional view around the inner web.

3A and 3B are cross-sectional views illustrating joints of reinforcing bars, where FIG. 3A shows a lap joint and FIG. 3B shows a mechanical joint.

FIG. 4 is a cross-sectional view of a connecting portion between unit buried molds.

[Explanation of symbols]

1 ... Buried formwork, 2 ... Projected rebar, 3 ... Upper plate, 4 ...
・ Bottom slab, 5 ・ ・ Inner web, 6 ・ ・ Outer web, 7 ・
・ Horizontal girder, 8 ・ ・ Manhole, 9 ・ ・ Diversion formwork, 10 ・ ・
Other member reinforcement, 11 ... Mechanical joint

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Shinbo 2-19-1 Tobita-Su, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute

Claims (1)

[Claims] 1. A reinforced concrete buried formwork having reinforcing bars protruding in four directions.