JPS63189527A - Cylindrical formwork - Google Patents

Abstract

PURPOSE:To prevent the leakage of concrete by providing many openings vertically in the central parts of a flexible sheet on the bottom. CONSTITUTION:Two angular parts 21 are connected at places by round bars 22 in a ladder form and both ends of a flexible sheet 10 having openings 15 between its filling yarns are attached to the angular parts 21 to form a lower formwork 20. The formwork 20 is set on undulatory natural ground 30, a reinforcing bar cage 40 is set on the formwork 20, and anchors 41 are driven into the ground 30 to join the formwork 20 and the cage 40 with the anchors 41 for fixation. A semicylindrical upper formwork 50 is fitted on them and join with the formwork 20 to form a cylindrical formwork 60. Concrete 70 is placed into the formwork 60.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylindrical formwork used when pouring concrete frames.

[Conventional technology]

When pouring concrete frames, the semi-cylindrical formwork used conventionally causes concrete to leak from the gap between the ground and the formwork.To solve this problem, the inventor filed a patent application filed in -25624, patent application No. 125695-1980,
In Japanese Patent Application No. 61-262962, we proposed a cylindrical formwork whose bottom surface was made of a flexible sheet.

It is extremely convenient to use a cylindrical formwork that is completed in whole or in part using a flexible sheet to prevent leakage of concrete.

However, it has been pointed out that a drawback is that the poured concrete body and the ground are blocked by the sheet.

[Problem that the invention seeks to solve]

The purpose of this invention is to solve the above-mentioned problem of isolation between concrete and the ground.

[Means to solve problems]

For this purpose, the present invention provides a large number of openings in the vertical center of the bottom surface of the cylindrical form used for concrete pouring.

[Effect]

With this configuration, the poured concrete can be prevented from leaking between the formwork and the ground by the flexible sheets on both sides of the bottom, and some of the concrete can also flow out to the bottom from the opening in the center. , the isolation between the concrete body and the ground can be avoided.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

What is shown in FIG. 1 is a band-shaped flexible sheet 10 forming the bottom surface of a cylindrical form. In this sheet, both side parts 11 are made of a normal plain-woven fabric 12, but the central part 13 in the longitudinal direction has no warp threads and is made up only of weft threads 14. Therefore, the weft threads can move freely to some extent, and between the weft threads there is no warp. The structure is such that an opening 15 is formed in the opening 15.

As shown in FIG. 2, two long angle members 21 are connected in places in a ladder shape using transverse round rods 22, and both sides of the flexible sheet 10 are connected to the angle members. The lower formwork 20 is constructed by attaching it. The flexible sheet should be wider than the gap between the angle members, and should be installed with a margin.

As shown in FIG. 3, the lower formwork 20 is installed on top of the uneven ground 30. The reinforcing bars 40 are placed on the lower formwork, the anchors 41 are driven into other threads, and the lower formwork and reinforcing bars are fastened to the anchors. From above, a semi-cylindrical upper formwork 50
The cylindrical formwork 60 is completed by covering it and connecting it with the lower formwork.

Concrete 70 is poured into such a cylindrical form. The flexible sheet is pressed against the ground 30 by the concrete, and the sides 11 of the sheet are attached to the lower edge 61 of the cylindrical formwork.
In order to prevent concrete from leaking between the concrete and the ground, in the center of the sheet-like material, the concrete passes through the opening formed by pushing away the weft threads and enters between the other mounds.

〔supplementary explanation〕

The gist of this invention is that when the bottom surface is made of a flexible sheet-like material, leakage of concrete from the gap between the lower edge of the cylindrical form and other piles is prevented, but the sheet-like material completely separate them. To eliminate this drawback, concrete or mortar is allowed to leak from a portion of the bottom.

Therefore, it is important to provide a large number of openings in the longitudinal center of the sheet-like material with a size large enough to allow concrete to leak, that is, with each side IQmn or more. Although the shape and forming method of the opening are not particularly limited, for example, the following method may be used.

As shown in FIG.
Three strips of the mesh body 16 of No. 3 are sewn together to form a band shape.

As shown in FIG. 5, the entire structure is made of a nonwoven fabric 17, and a large number of openings 15 are provided in the center.

As shown in FIG. 6, both side portions 11 are formed of woven fabric 12,
For example, woven fabrics on both sides are connected transversely with strong strings 18 in places.

In order to prevent the sheet-like material from protruding beyond the gap in the formwork more than necessary, it is effective to fix the sheet-like material to the ground using anchor bins with footers at appropriate intervals.

The semi-cylindrical upper formwork 50 is not limited in its material or shape, but may be made of rigid materials such as iron, aluminum, plastic, or wood, as well as flexible materials such as woven fabric, nonwoven fabric, or rubber sheet. You may.

〔effect〕

Since this invention is constructed as described above, concrete leaks from the opening in the center of the bottom flexible sheet.
The concrete body and the ground are not completely isolated,
Anxiety is removed.

[Brief explanation of the drawings] Figures 1, 4, 5, and 6 are plan views of the flexible sheet, Figure 2 is a front view of the lower formwork, and Figure 3 shows the construction method. FIG. 10... Flexible sheet, 11... Side part, 12... Woven fabric,
13...Central part, 14...Weft, 15...Opening, 16...
-Network, 17..Non-woven fabric, 18..String, 20..Bottom formwork, 21..Angle material, 22..Round bar, 30..Mound.
40...Reinforcement capacity, 41...Anchor, 50...Upper formwork,
60...Cylindrical formwork, 61...Lower edge, 70...Concrete.

Claims (5)

[Claims] (1) In a cylindrical formwork for pouring concrete slopes whose bottom surface is made up of a flexible sheet material, there are a number of openings in the vertical center of the flexible sheet material on the bottom surface. A cylindrical formwork characterized by the provision of. (2) The central portion is made of a net (
The cylindrical formwork described in section 1). (3) The cylindrical formwork according to claim (1), wherein the central portion is made of a perforated sheet. (4) The cylindrical formwork according to claim (1), wherein the central portion is made of a woven fabric from which the warp or weft is partially removed. (5) The cylindrical formwork according to claim (1), wherein the central portion is constituted by a set of transverse string-like objects that connect the sheet-like objects on both sides at certain places.