JPH0788667B2 - Lower formwork for concrete formwork - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a lower formwork for a concrete formwork.

<Prior Art> Generally, when constructing a concrete method frame, a semi-cylindrical form is used.

In this conventional formwork, if there is unevenness in the ground, a gap is created between the formwork and the ground, and there is a problem that concrete leaks out from this gap.

Therefore, it has been proposed to prevent leakage of concrete from the bottom of the mold by using a mold in which a part or all of the mold is formed of a flexible sheet in a tubular shape.

<Problems to be Solved by the Present Invention> In the above-mentioned conventional formwork, although leakage of concrete can be regulated, since the ground and the law frame are blocked by the sheet-like material, the ground and the law frame There remains anxiety about the adhesion.

From this situation, it is possible to prevent concrete leaks,
Moreover, it is desired to propose an improved technique capable of ensuring the adhesion to the natural ground.

<Purpose of the present invention> The present invention has been made in view of the above points, and can prevent leakage of concrete, and can improve the adhesion between the ground and the legal frame, a lower mold for a concrete legal frame. The purpose is to provide a frame.

<Structure of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

<A> Lower formwork The lower formwork 1 comprises a flexible sheet 2 and a ladder-shaped ladder frame 3 as shown in FIGS.

<B> Flexible Sheet The flexible sheet 2 is a flexible sheet-like material, and is composed of two types of members having different purposes and functions.

That is, both sides 21 and 21 in the longitudinal direction of the flexible sheet 2 are made of a material that prevents the permeation of concrete, and the central portion 22 between the two sides 21 and 21 has a large number of openings to form the concrete. It is made of transparent material.

As the material of the side portion 21, for example, woven cloth or non-woven cloth can be used.

The material of the central portion 22 may be, for example, a mesh having a coarse mesh, a string may be crossed between the side portions 21, or an opening may be opened in the same material as the side portion 21.

As a means for joining the central portion 22 and the side portions 21, 21, they are joined by sewing, bonding or the like.

In addition, the outermost ends of the both side portions 21, 21 are closed in a bag shape and the locking bag 23
To form.

<C> Ladder Frame The ladder frame 3 is formed by welding a plurality of transverse rods 32 between two parallel rods 31, 31 to form a ladder shape.

Both ends of each cross bar 32 are bent downward.

<Operation> Next, a method of constructing the method frame will be described with reference to FIGS.

<A> Assembly of lower formwork First, a rod member 24 such as a reinforcing bar is inserted into the locking bag 23 of the flexible sheet 2, and the rod member 24 is fixed to the ladder rod 3 by welding or the like to form the lower formwork. Assemble 1.

When assembling the lower formwork 1, the flexible sheet 2 is wider than the interval between the parallel bars 31, 31 of the ladder frame 3 and is attached with a margin, and concrete is placed on the flexible sheet 2 It is characterized in that it is loosened so as to be interposed between the entire bottom surface of the slope and the ground surface.

Then, the lower formwork 1 is laid on an uneven slope.

The laying shape of the lower mold 1 is similar to a known shape such as a lattice shape.

The lower formwork 1 is assembled on the slope or is installed with a flat surface other than the slope.

<B> Attachment of Reinforcing Bar Basket After placing and fixing the reinforcing bar cage 4 on the ladder frame 3, the lower formwork 1 and the reinforcing bar cage 4 are fixed to the anchor 5 driven into the slope.

<C> Installation of Upper Formwork Next, a semi-cylindrical upper formwork 6 is covered from above the rebar cage 4 and the lower formwork 1, and the two formwork 1 and 6 are connected via a connecting tool 7.

The shape of the upper mold 6 is determined by the cross-sectional shape of the method frame to be molded, and the material is a woven fabric, a non-woven fabric, a resin sheet in addition to a rigid material such as iron, aluminum, resin, or wood. It may be a material having flexibility such as.

The connecting tool 7 is composed of an L-shaped hook member 71 formed by an angle or the like and a linear short member 72. The hook member 71 and the short member 72
After the base end of is inserted into the transverse rod 32 and locked, the bolt 73 protruding from the free end of the short member 72 is inserted into the free end of the hook member 71 and tightened with a nut, so that the upper frame 6 is fixed. It has a structure that can be restrained.

<D> Placing of concrete (FIG. 3) Concrete 8 is poured into a cylindrical form formed by the lower form 1 and the upper form 6.

As a result, the entire flexible sheet 2 is deformed following the unevenness of the natural ground.

In particular, at a place where a gap is generated between the upper mold 6 and the ground, both side portions 21, 21 of the flexible sheet 2 are pressed toward the ground side to close the gap, so that the leakage of the concrete 8 is prevented. Regulated.

Further, in the central portion 22 of the flexible sheet 2, the concrete 8 penetrates and directly contacts the ground.

<E> Demolding After a predetermined curing period, the connector 7 and the upper mold 6 are removed.

The lower formwork 1 is buried in the legal frame.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

<a> By using a flexible sheet made of a combination of a material that blocks the permeation of concrete and a material that permeates the concrete, it is possible to prevent the concrete from leaking on both sides of the flexible sheet, and at the same time, the central portion of the flexible sheet The contact between concrete and the ground can be achieved.

Therefore, concrete leakage can be surely prevented in construction, and a structurally stable legal framework can be obtained.

<B> The lower mold components other than the flexible sheet are only bar members.

Therefore, not only the lower mold can be easily manufactured, but also the cost can be reduced.

<C> The flexible sheet used for the lower formwork of the present invention is mounted so that it is slackened so as to be interposed between the entire bottom surface of the method frame and the ground surface in a state where concrete is cast on the sheet. It is characterized by

As a result, the entire bottom surface of the legal frame conforms to the unevenness of the ground surface, enabling stable construction.

<D> In the prior art, there is one in which a concrete outflow hole is formed only in the central portion in the longitudinal direction of a rigid plate body. However, when a plate body is used instead of a flexible sheet as described above, A gap is inevitably formed between the uneven surface and the concrete, and concrete leaks out through the gap.

However, in the present invention, since the outflow holes are formed in the flexible sheet, the flexible sheet adheres closely to the uneven surface of the natural ground, and no gap is generated between the flexible sheet and the natural ground.

Therefore, it is possible to reliably prevent external leakage of the placed concrete.

[Brief description of drawings]

1 is a perspective view of the entire lower mold according to the present invention. FIG. 2 is an explanatory view of a construction method for constructing a method frame, and is a cross-sectional view when the frame of the form is completed. Cross-sectional view of formwork when concrete is placed in the frame

Claims (1)

[Claims] 1. A lower formwork for constructing a tubular formwork for a concrete method frame by placing an upper formwork having a semi-cylindrical cross section on a slope and comprising a plurality of traverses between two parallel bars. It consists of a ladder frame to which a rod is fixed, and a flexible sheet integral with the ladder frame. Both sides of the flexible sheet in the longitudinal direction are formed of a material that prevents the permeation of concrete, and Lower formwork for concrete formwork, characterized in that the central part is made of concrete-permeable material.