JPH04309620A - Underground beam and working method thereof - Google Patents

Abstract

PURPOSE:To obtain an underground beam and its working method whereby increase in quality and shortage of work period of buildings can be attained. CONSTITUTION:A groove 1 with a depth equivalent to that of an underground beam is excavated. Reinforcing bars for supporting 3 are erected on both sides of the bottom of the groove 1. Steel plates such as keystone plate 5, etc., are built into the groove 1. Inside the steel plates, underground beam reinforcements 15 are assembled. Slab reinforcements 17 are assembled integrally together with the underground beam reinforcements 15. Concrete for the underground beam 19 and slab 21 are worked integrally. Accordingly the excavating width of the groove is made narrow and the amount of soil work is reduced. Separators, etc., are not required for assembling the underground beam reinforcements and also de-molding work is eliminated. The reinforcement assembly work is simplified and joints between the slabs and underground beams are eliminated to increase quality. Also its work period is approximately halved than before.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground beam in which an underground beam and a floor slab are continuously integrated, and a method for constructing the same.

0002

[Prior Art] Conventionally, when constructing the foundation of a house,
A formwork made of wood or iron plates was constructed, concrete was poured inside the formwork, and the form was removed after the concrete had hardened. Of course, before constructing the formwork, which is the same for both cloth foundations and underground beams, excavate the soil in the axial direction to create a groove, and fix the formwork within this groove with end pieces or the like. After demolding, the concrete and nails adhering to the formwork were removed in order to reuse it, and in the case of iron plates, a thin layer of oil was applied to prevent rust.

0003

[Problem to be solved by the invention] Description: In order to perform formwork work on conventional foundations and underground beams, it is necessary to excavate a width equal to the width of the underground beam to be actually constructed plus the width for the work. there were. As a result, the amount of backfilling soil had increased. In addition, there was an underground beam joint under the slab, which could not be said to be of the best quality. When demolding work and formwork construction were included, work efficiency was also not good. The present invention has been made in view of the above circumstances, and its purpose is to reduce the amount of earthwork work such as simple form work, narrow excavation width, and small amount of backfilling soil, and to omit work. An object of the present invention is to provide a beam and its construction method.

0004

[Means for Solving the Problems] In order to achieve the above object, the underground beam according to the present invention has the following features when constructing the underground beam:
A steel plate such as a keystone plate is erected and supported as a formwork using supporting reinforcing rods that are erected almost vertically in the excavation trench.
The underground beam reinforcing bars are placed inside the beam, and the slab reinforcing bars are assembled together, and concrete is poured over these to form the underground beam and slab as one unit. The construction method is to excavate a trench that is approximately the same width as the underground beam, and then insert support rods into the soil intermittently along both sides of the trench. Build it while supporting it, backfill the outside, and then install beam reinforcing bars within the formwork.
Furthermore, slab reinforcing bars were assembled at the upper end of the slab, and the concrete for the underground beam and slab was cast continuously and integrally, and the formwork was used as a waste formwork.

[0005]

[Operation] The underground beam reinforcing bars and the slab reinforcing bars are assembled together and concrete is poured so that there is no concrete pouring between the underground beams and the slab, and the underground beam formwork becomes a waste formwork. . Since steel plates such as keystone plates are used as formwork, they are located on the surface side of the concrete, and their oxidative expansion will not cause damage to the concrete from within. Further, the formwork is supported from the inside using support rods, and then the outside of the formwork is backfilled to support the formwork from the inside and outside. Therefore, no end pieces or separators are used, and there is no need to excavate outside the formwork.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. First, as shown in FIG. 1, a groove 1 is excavated to a width slightly wider than the cross section of the underground beam, that is, a width corresponding to the thickness of the formwork added to the cross section of the beam. Reinforcement rods 3 are erected intermittently along both sides of the inside of this groove 1. Although the reinforcing bar 3 is called a support bar, it is the same thing. The reinforcing bar 3 is preferable because it can ensure sufficient strength even though it is small in price and cross section. The lower part of the reinforcing bar 3 is inserted into the soil so that it is independent enough to support the formwork. At this time, the top of the reinforcing bar 3 is long enough to protrude slightly above the ground surface. Next, considering the advantage of having a shape that is hard to distort, the keystone plate 5 is placed against the outside of the reinforcing bar 3, and the keystone plate 5 is supported by the reinforcing bar 3. The keystone plate 5 serves as the formwork for the underground beam. Scatter gravel on the bottom of the trench 1 and the ground surface, drive a short support stake 7 at an arbitrary point located from the top of the reinforcing bar 3 toward the outside of the trench 1, and Stretch wire 9 between. Incidentally, the maximum distance between the keystone plate 5 and the excavated side surface is about 300 mm. As a reminder, groove 1 has an excavated cross-sectional shape that spreads upward from the bottom. Further, the height at which the support pile 7 protrudes above the ground surface is such that it can be sufficiently hidden (buried) within the thickness of the cast concrete slab. After that, the inside of the groove 1 and the outside part of the keystone plate 5 is backfilled, and concrete 11 is laid on the bottom of the groove 1 and the ground surface. The support piles 7 oppose the earth pressure of this backfill earth and sand 13, and maintain the reinforcing bar 3 in its position so as not to be distorted. This completes the reinforcement arrangement for configuring the underground beam, and will be described in detail below with reference to FIG. 2. A stirrup is arranged inside the groove 1, and underground beam reinforcing bars 15 are laid out from possible locations, and sequentially configured with lap joints. Next, slab reinforcements 17 are connected to the upper ends of the underground beam reinforcing bars 15. Finally, concrete is cast and cured in the groove 1 and the slab part, so that the underground beam 19 and the slab 21 are cast seamlessly. The support piles 7, reinforcing rods 3, and keystone plates 5 are discarded. In other words, it has become a discarded formwork.

[0007]

[Effects of the Invention] As explained in detail above, according to the underground beam and its construction method according to the present invention, a steel plate such as a keystone plate can be used as a supporting reinforcing rod that is erected from the inside of an excavated trench into the trench. The underground beam reinforcing bars placed inside the steel plate such as the keystone plate are assembled together with the slab reinforcing bars, and concrete is poured into them, making it possible to connect the underground beams under the slab. This has the effect of improving quality. In addition, there is no need for separators or excavation widths for formwork work, and the amount of backfilling soil can be significantly reduced, which has the effect of improving workability and shortening the construction period.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a state in which reinforcement arrangement setup is completed in an embodiment of the present invention.

FIG. 2 is a sectional view showing the embodiment when the construction work is completed.

[Explanation of symbols]

1 Groove ３　　　　Rebar rod 5 Keystone plate 7 Support pile 9 Platform line 11 Discarded concrete 13　Sediment 15 Underground beam reinforcement 17 Slab muscle 19 Underground beam 21 Slab

Claims (2)

[Claims] [Claim 1] When constructing an underground beam, a steel plate such as a keystone plate is erected as a formwork and supported by supporting reinforcing rods that are erected almost vertically in an excavation trench, and the underground beam is placed inside of it. An underground beam characterized by arranging reinforcing bars, assembling these and slab reinforcing bars together, and pouring concrete over these to form an underground beam and a slab as one unit. [Claim 2] A trench with approximately the same width as the underground beam is excavated, and support rods are inserted into the soil intermittently along both sides of the trench, and the support rods are used to The formwork is erected while supporting it, the outside of it is backfilled, and then beam reinforcing bars are installed within the formwork, and slab reinforcing bars are integrated into the upper end of the formwork to make the concrete of the underground beam and slab continuous and integrated. A method for constructing an underground beam, characterized in that the formwork is used as a formwork.