JP2790959B2 - Underground beam construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground beam provided on a foundation of a building.

[0002]

2. Description of the Related Art An underground beam provided as a reinforced concrete building foundation, for example, has been constructed as follows. In other words, excavate underground, cast discarded concrete,
The underground beam and a part of the building are integrated on it and concrete is poured. At this time, the lower main bar was arranged at the lower end of the underground beam, that is, the upper part of the discarded concrete, and the upper main bar was arranged at the upper end thereof, that is, inside the building.
Then, the stirrup bars are wound around the lower main bar and the upper main bar in the vertical direction.

In actual construction, it is conceivable to use two formwork members forming both side surfaces of an underground beam and leave them as they are after placing concrete (Japanese Patent Publication No. 54-5207). In this case, the two formwork members mounted on the discarded concrete are connected to each other by a member called a separator so that the two formwork materials do not fall outside due to the lateral pressure of the poured concrete. ing.

[0004]

However, according to the conventional construction method, a large amount of work is required for rebar arrangement work and formwork embedding work. The height of the beam has been increased and the amount of work at high places has increased, and labor saving has been desired.

[0005] As described above, to save labor,
Even when a plurality of form materials are used, a connecting operation by a separator must be performed in order to prevent the form materials from falling down. In addition, a complicated operation of arranging a reinforcing bar, such as a stirrup bar, for increasing the strength of the underground beam between the connected form members has to be performed on site.

The present invention has been made in order to solve the above problems, and uses two precast concrete plates as a formwork, does not require a separator connecting operation, and can reduce on-site work. The purpose is to provide a construction method for beams.

[0007]

In order to achieve the above object, the present invention integrates the upper end of an underground beam into a building and arranges a lower main bar and an upper main bar at the lower and upper ends thereof. In the method of constructing an underground beam constructed by arranging stirrup bars between the bottom main bar and the top main bar, the vertical bars constituting the vertical portion of the stirrup bars are buried, and both sides of the underground beam The two precast concrete plates forming the formwork are integrally united with each other at predetermined intervals by means of spacing bars in advance, and on the other hand, the bottom main reinforcing bars are placed on the cast-out concrete. A U-shaped streak that is wound and forms the lower end of the stirrup streak is arranged, and then the unitized precast concrete plate is mounted on the discarded concrete, and then a U-shaped streak that forms the upper end of the stirrup streak The top main reinforcement is pre-grounded on the united precast concrete plate, and the U-shaped reinforcement and the vertical reinforcement at the upper and lower ends of the stirrup are overlapped to form a joint structure. It is characterized in that the side formwork is attached, and finally concrete is poured.

[0008] In the invention of claim 2, the spacing maintaining muscle is a truss muscle or a spiral muscle.

[0009]

The two precast concrete plates serving as the formwork of the underground beam are unitized in advance. At this time, the precast concrete plates are integrally joined to each other by the spacing bars, and furthermore, the precast concrete plates are also provided with the vertical bars constituting the vertical portions of the stirrup bars.

[0010] At the site, the U-shaped reinforcing bar wound around the lower main bar and constituting the lower end of the stirrup bar is arranged on the previously cast discarded concrete, and the unitized precast concrete plate is installed. Then, from above, a U-shaped streak constituting the upper end of the stirrup streaks and an upper main streak are pre-grounded. Therefore, the work of arranging the bars on the site is saved. At this time, the U-shaped streaks at the upper and lower ends of the stirrup streaks and the longitudinal streaks constitute a lap joint. Then, the formwork on the building side is attached to the precast concrete plate, and then concrete is poured,
Underground beams and buildings will be built together.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, an underground beam 3 is provided on a waste concrete 1 in an underground portion. A floor slab 5 of the building is provided integrally on the underground beam 3. At the lower end of the underground beam 3, that is, above the abandoned concrete 1, a lower main bar 7 is arranged in the horizontal direction. Similarly, at the upper end of the underground beam 3, that is, inside the floor slab 5, an upper main bar 9 is arranged in the horizontal direction. A stirrup bar 11 is wound around the upper main bar 9 and the lower main bar 7. The stirrup streaks 11 have a substantially rectangular shape as shown in the figure, are arranged in a vertical direction, and oppose a shearing force. Also, truss bars are arranged in the lateral direction as spacing bars 13. As will be described later, the spacing bars 13 are previously embedded in two precast concrete plates 15 forming both side surfaces of the underground beam 3. The formwork 17 supporting the lower surface of the floor slab 5 is also a precast concrete plate.

The procedure in this embodiment will be described below with reference to FIG. First, two precast concrete plates 15 serving as a formwork of the underground beam 3 are unitized in a factory in advance. That is, by keeping a predetermined interval,
Are integrally joined together.

The spacing bars 13 are arranged on the reinforcing bars 18 of the precast concrete plate 15 itself. Therefore, after the precast concrete plate 15 is manufactured, the spacing bars 13 are partially embedded in the precast concrete plate 15. Further, the vertical bars 11A are arranged in the precast concrete plate 15. The vertical streaks 11 </ b> A constitute a vertical portion of the stirrup streaks 11.

At the site, the ground is excavated and the concrete 1 is poured. The U-shaped muscle 11B and the lower main muscle 7 are horizontally arranged thereon.

On the other hand, the cast concrete 1
The precast concrete plate 15 unitized at the factory is installed with the U-shaped streak 11B and the like sandwiched therebetween. By this time, stirrup streaks 11
An upper reinforcing bar 19 is prepared in which the U-shaped reinforcing bar 11C and the upper main bar 9 constituting the upper end of the upper bar are ground in advance. This upper reinforcement 19
From above the installed precast concrete plate 15.

Then, so to speak, upper and lower three parts 11A, 1
Each part of the stirrup streak 11 divided into 1B and 11C is overlapped and formed to complete the substantially rectangular stirrup streak 11. That is, U of the upper and lower ends of the stirrup streak 11
The type bars 11C and 11B and the vertical bars 11A are referred to as a lap joint 21. Therefore, each tip of the U-shaped muscles 11B and 11C and the longitudinal muscle 1
1A is overlapped with a certain dimension in the vertical direction.

At the upper end of the precast concrete plate 15, a formwork 17 for supporting the floor slab 5 of the building from below is attached. After the reinforcing work and the erection work are completed in this way, the concrete 23 is poured. When the poured concrete 23 hardens, the underground wall 3 and the floor slab 5
Are integrated.

As described above, according to this embodiment,
Since the unitized precast concrete plates 15 are joined to each other by the spacing bars 13 at the factory, there is no need for the work of connecting them with a separator at the site as in the related art. In other words, the spacing bars 13 can sufficiently prevent the precast concrete plate 15 from falling down due to the lateral pressure of the cast concrete 23.

Since the spacing bars 13 are already arranged in the factory and partly embedded in the precast concrete plate 15, there is no need to arrange them again on site.

Further, by dividing the stirrup streak 11 into three parts 11A, 11B, and 11C, which are so-called upper, middle, and lower portions, the U-shaped streak 11C and the upper end main streak 9 constituting the upper end of the stirrup streak 11 are previously ground. Therefore, the arrangement work can be performed in parallel with other operations, and the efficiency of the arrangement work can be improved. Therefore, it is possible to reduce troublesome work as compared with the case where the stirrup bars 11 and the spacing bars 13 are arranged after the precast concrete plate 15 serving as the formwork is installed as in the related art.

Further, by connecting the U-shaped bars 11B and 11C of the stirrup bars 11 and the vertical bars 11A and the vertical bars 11A with the lap joint 21, the precast concrete plate 15 is unitized for the work of connecting these reinforcing bars. Alternatively, there is no need to form a vertical streak from the lower end, so that the production efficiency and on-site work efficiency of the precast concrete plate 15 can be improved.

In the above-described embodiment (FIGS. 1 and 2), the spacing bars 13 are formed by two precast concrete plates 1.
Although the truss bars are arranged in a zigzag manner in the vertical direction between the portions 5, spiral bars 25 may be used as shown in FIGS. 3 to 5 in other embodiments. In the present embodiment, the spiral streaks 25 are repeatedly drawn in a substantially closed shape in a horizontal plane, and are spirally arranged in the vertical direction. FIG. 3 shows an eight-shape. By using the figure-shaped spiral streaks 25, each reinforcing bar that looks as if a large number of bars are arranged between the two precast concrete plates 15 is inclined not only vertically but also in a plane. In addition, the rigidity against the force for shifting the precast concrete plates 15 in the vertical and horizontal directions can be improved.

Further, as shown in FIG. 4, it may be formed in a square shape. Further, as shown in FIG. 5, the shape may be triangular.

By using the spiral streaks 25 as the spacing streaks 13, when manufacturing the unitized precast concrete plates 15 at a factory, the work of arranging the bars is easy and the manufacturing efficiency can be improved.

[0025]

As described above, according to the underground beam construction method of the present invention, the upper end of the underground beam is integrated with the building, and the lower main bar and the upper main bar are arranged at the lower and upper ends. In the construction method of underground beams constructed by arranging stirrup bars between the bottom main bar and the top main bar, vertical bars constituting the vertical portion of the stirrup bars are buried, Two precast concrete plates forming both sides and forming a form are integrally united with each other while maintaining a predetermined interval with a spacing streak in advance to form a unit. The main reinforcement is wound to arrange a U-shaped reinforcement constituting the lower end of the stirrup reinforcement, and then the unitized precast concrete plate is mounted on the discarded concrete, and then the U-formation constituting the upper end of the stirrup reinforcement is provided. Type muscle The top main reinforcement is pre-grounded on the united precast concrete plate, and the U-shaped reinforcement and the vertical reinforcement at the upper and lower ends of the stirrup are overlapped to form a joint structure. Since the formwork on the side was attached and concrete was finally cast, the two precast concrete plates were integrally joined together by the spacing streaks in advance. You don't have to.

Further, the stirrup streak is divided into upper, middle and lower parts, and the streak forming the vertical portion is buried in advance in the unitized precast concrete plate, and furthermore, constitutes the upper end of the stirrup streak. By pre-fabricating the U-shaped reinforcement and the upper-end main reinforcement, the arrangement work at the site can be performed simply by arranging the upper, middle, and lower parts, thereby reducing the work. Moreover, by using the lap joint, it is not necessary to expose the reinforcing bars from the upper and lower ends of the precast concrete plate for joining the reinforcing bars, so that the precast concrete plate can be efficiently manufactured and the workability on site is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a schematic exploded perspective view of FIG.

FIG. 3 is a perspective view showing a first example in which a spacing muscle in FIG. 2 is a spiral muscle.

FIG. 4 is a perspective view showing a second example in which the spacing muscle in FIG. 2 is a spiral muscle.

FIG. 5 is a perspective view showing a third example in which the spacing muscle in FIG. 2 is a spiral muscle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discarded concrete 3 Underground beam 5 Floor slab 7 Lower main bar 9 Upper main bar 11 Stirrup bar 11A Vertical bar 11B, 11C U-shaped bar 13 Spacing bar 15 Precast concrete plate 17 Formwork 18 Steel bar 19 Upper bar 21 Lap joint 23 Concrete 25 spiral streaks

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Haneishi 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office (72) Inventor Etsunori Tamura 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office (72) Inventor Tatsuya Wakisaka 4-640 Shimoseito, Kiyose-shi, Tokyo, Japan Inside Obayashi Corporation Technical Research Institute (72) Inventor Noriyuki Furuya 4-640 Shimoseito, Kiyose-shi, Tokyo, Japan Obayashi Corporation Within the Technical Research Institute (72) Kohei Kurita 4-640 Shimoseito, Kiyose-shi, Tokyo Inside the Obayashi Corporation Technical Research Institute (56) References JP-A-5-79044 (JP, A) JP-A-5-106228 (JP) , A) (58) Fields studied (Int. Cl. ⁶ , DB name) E02D 27/00 E02D 27/08

Claims (2)

(57) [Claims] 1. An upper end of an underground beam is integrated with a building, a lower main bar and an upper main bar are arranged at the lower and upper ends thereof, and a stirrup bar is arranged between the lower main bar and the upper main bar. In the construction method of the underground beam to be built by the vertical stirrup,
The two precast concrete plates that form both sides of the underground beam and form a formwork are integrally united with each other at predetermined intervals by a spacing streaks to form a unit. A U-shaped reinforcing bar having a lower main bar wound thereon to form a lower end of the stirrup bar is disposed thereon, and then the unitized precast concrete plate is installed on the discarded concrete. The U-shaped reinforcing bar and the upper main bar are pre-grounded on the united precast concrete plate, and the U-shaped reinforcing bar at the upper and lower ends of the stirrup bar and the vertical bar are overlapped to form a joint structure. Underground beam construction method, in which the building-side formwork is attached to the converted precast concrete plate, and finally concrete is cast 2. The method according to claim 1, wherein the spacing bars are truss bars or spiral bars.