JPH0377350B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a concrete casting method for constructing spherical or circular structures such as egg-shaped sludge digesters, water tanks, oil storage tanks, silos, etc. The present invention relates to the placing device.

<Prior Art> Looking at the scale of recent spherical and circular structures such as egg-shaped digesters, small and medium-sized digesters in the 1,500 to 4,000 ton class are being planned and constructed in local cities.

As formwork and formwork support for concrete pouring to construct such small and medium-sized egg-shaped digesters, conventionally, concrete pouring and formwork assembly were carried out alternately, similar to PC tanks. Full scaffolding formwork, carried out in stages, is used.

<Problems to be Solved by the Present Invention> The conventional construction techniques for spherical and circular structures described above have the following problems.

<A> When using full scaffolding formwork, for example 15 to 20m
In order to lift concrete for the side walls to a certain height, the height of concrete to be lifted at one time is limited to about 1.5 to 1.8 m.

As a result, the concrete must be lifted several times and the construction period becomes extremely long, resulting in high costs.

<B> Since the concrete has to be lifted several times, many joint surfaces are formed in the concrete, which is a weak point in terms of liquid-tightness and air-tightness.

<C> Since the total scaffolding formwork uses a straight formwork, when the side wall has a curved surface like an egg-shaped sludge digestion tank, the curved surface in the meridian direction becomes a polygonal line.

For this reason, in the case of prestressed concrete, there was a problem that the prestressed steel material buried in the center of the wall could become eccentric.

<Objective of the present invention> The present invention was made to solve the above-mentioned problems, and allows construction of spherical and circular structures in a short period of time at low cost, while improving construction accuracy and quality of poured concrete. An object of the present invention is to provide a method for placing concrete for spherical or circular structures and a device for placing concrete therein, which can increase the performance of concrete.

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

<A> The pouring device of the present invention The pouring device of the present invention includes steel materials in the meridian direction and the circumferential direction, such as H steel, assembly fittings, separators,
And it consists of formwork.

In addition, in this embodiment, a case will be described in which an oval-shaped digestion tank is constructed among spherical and circular structures.

(1) H steel in the meridian direction (Figs. 1 and 7) H steel 1 is bent at a predetermined bending radius to match the shape of the structure to be constructed in the meridian direction.

This H steel 1 is assembled at a distance equal to the wall thickness of the structure in the meridian direction on the inside and outside of the structure.

Furthermore, assembly fittings 2 and 3, which will be described later, are attached to the H steel 1.

(2) Assembly fittings (Figures 3 to 7) There are two types of assembly fittings: assembly fittings 2 and assembly fittings 3.

First, the assembly fitting 2 shown in FIGS. 3 and 4 will be explained.

The assembly fitting 2 has two steel plates 21 facing each other,
The space between them is connected by a bending arm 22.

The bending arm 22 is constructed by stacking steel plates in a sandwich pattern and fixing them with bolts 23, and by loosening the bolts 23, the bending arm 22 can be bent.

One of the steel plates 21 is the H steel 1 in the meridian direction.
A long hole 24 is opened and a bolt 25 is inserted and attached.

Therefore, by loosening the bolt 25,
The assembly fitting 2 can be slid in the vertical direction.

Further, U bolts 26 are attached to the other steel plate 21 at two locations with the heads of the bolts positioned above and below, facing outward.

The space surrounded by the U bolt 26 and the steel plate 21 is
It is formed to a size that allows insertion of a circumferential H steel 4, which will be described later.

Next, the assembly fitting 3 shown in FIG. 5 will be explained.

In place of the U bolt 26 used in the above-mentioned assembly fitting 2, the assembly fitting 3 is attached with a pedestal 31 made of steel plates assembled in a U-shape.

The H steel 4 in the circumferential direction is placed on the pedestal 31, and is tightened from the side with a holding bolt 32 so as not to swing.

As shown in Fig. 7, the mounting positions of these assembly fittings 2 and 3 are such that the assembly fittings 2 and 3 are arranged alternately on the outer H steel 1 in the meridian direction, and the assembly fittings 2 and 3 are placed alternately on the inner H steel 1. Place only the metal fittings 3.

Further, the inner and outer assembly fittings 2 and 3 are attached to opposing positions, respectively.

In addition, as shown in FIG. 6, it is also possible to interpose a simple block-shaped metal fitting between the H steel 1 and the H steel 4 and attach them with bolts.

(3) H steel in the circumferential direction (Figs. 1 and 7) H steel 4 is bent at a predetermined bending radius to match the circumferential shape of the structure to be constructed.

This H steel 4 has assembly fittings 2 provided on the inside and outside,
3, it is attached in the circumferential direction across the meridian H steel 1.

At this time, the H steel 1 in the meridian direction is bent equally with the inner and outer surfaces of the side walls of the structure, but in the case of the H steel 4, the assembly metal fittings 2 and 3 are involved, so the outer H steel 4 is bent accordingly. The inner H steel 4 is formed to be small in diameter and large in diameter.

(4) Separator (Fig. 7) The separator 5 is a thin steel bar with threads on both ends.

This separator 5 has internal and external H in the meridian direction.
The steel parts 1 are connected at intervals equal to the wall thickness.

(5) Formwork (Figs. 7 and 9) As shown in Fig. 9, the formwork 6 is made by attaching a plurality of reinforcing horizontal crosspieces 62 and vertical crosspieces 63 to one side of plywood 61.

The width of the plywood 61 is slightly shorter than the width of the H steel 1, and the length of the horizontal crosspiece 62 is slightly longer than the width of the plywood 61.

At this time, if the height of the formwork 6 is formed to be about 45 cm to 90 cm, concrete can be placed and compacted sufficiently, so that high quality concrete can be obtained.

<B> Casting method of the present invention In the case of a vertically symmetrical structure as in this embodiment, concrete is poured in two parts, upper and lower, as shown in FIGS. 1 and 2.

Therefore, the above-mentioned pouring device only needs to be manufactured for a hemisphere, which is economical.

The following explanation assumes that the lower hemisphere has already been constructed and the upper hemisphere is to be constructed.

(1) Assembling the H steel in the meridian direction (Figures 2 and 7) Assemble the H steel 1 in the meridian direction over the entire upper hemisphere of the structure.

First, mark H in the meridian direction on the existing concrete 7.
The lower end of the steel 1 is fixed with a bolt 11.

Next, the H steel 1 is connected in the meridian direction by welding, bolting, or the like.

A separator 5 is passed through the inner and outer H steels 1, and the threaded portions at both ends of the separator 5 are fixed with nuts.

This separator 5 determines the wall thickness of the structure and can receive lateral pressure during concrete pouring.

(2) Assembling the H steel in the circumferential direction (Figs. 2 and 7) Fix the H steel 4 in the circumferential direction to the assembly fittings 2 and 3 attached to the H steel 1 in the meridian direction, and attach it to the inside and outside of the structure. Attach circumferentially.

The connection of the H steel 4 in the meridian direction is performed by welding, bolting, or the like.

At this time, in order to install H steel 4 horizontally,
Bend the assembly fittings 2 and 3 appropriately.

By assembling the H steels 1 and 4 as described above, the weight of the entire concrete can be supported.

That is, the assembly fittings 2 and 3 are moved from the H steel 1 in the meridian direction.
The force transmitted through can be received by the compressive force of the H steel 4 in the circumferential direction.

(3) Assembling the inner (or outer) formwork (Figures 7 and 9) After assembling the H steels 1 and 4, the plywood 61 of the formwork 6
Insert between the inner (or outer) H steels 1 in the meridian direction.

Since the formwork 6 is made of wood, it is bent in the same way as the H steel 1 when it is fitted into the H steel 1.

Therefore, unlike conventional linear formwork, the curved surface in the meridian direction of the structure does not become a polygonal line.
Good construction accuracy can be obtained.

When assembling, it is convenient to assemble either the inside or outside side first to save time and effort when pouring concrete.

When fitting the formwork 6, use the camber 6.
4 is driven between the H steel 1 and the vertical crosspiece 63 and fixed.

Further, a thin plate 65 is fitted into the gap between the plywood 61 and the H steel 1 as a sealing material.

(4) Assembly of reinforcing bars and prestressing steel (Fig. 7) In the case of prestressed concrete, reinforcing bars 8
and PC steel material 9 are placed inside.

Then, a part of the PC steel material 9 is exposed to the outside so that it can be tensioned.

(5) Placing concrete (Fig. 8) Gradually assemble the unassembled formwork 6, either the outside or the outside, one step at a time, and while following the concrete 71 in the circumferential direction, continuously pour the concrete 71 to a predetermined height. Pour concrete.

After the concrete 71 has been poured, the formwork 6 and the H-steels 1 and 4 are dismantled to complete the work.

<Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

<B> When using conventional total scaffolding formwork, the concrete must be lifted several times and the concrete is poured, resulting in a very long construction period and high costs.

In contrast, the present invention allows concrete to be placed continuously.

Therefore, the construction speed is fast, the construction period is short, and costs can be reduced.

<B> Conventionally, concrete has to be lifted several times before being poured, resulting in a large number of joint surfaces in the concrete, which are weak points in terms of liquid-tightness and air-tightness.

However, since the present invention allows concrete to be poured continuously, compared to the conventional method,
The joint surface was significantly reduced.

Therefore, weaknesses in liquid tightness and airtightness can be overcome, and the strength of the structure can be increased.

<C> Since the total scaffolding formwork uses a straight formwork, when the side wall has a curved surface like an egg-shaped sludge digestion tank, the curved surface in the meridian direction becomes a polygonal line.

Therefore, in the case of prestressed concrete, the prestressed steel material buried in the center of the wall may become eccentric, which is a problem.

However, in the present invention, the side wall can be constructed in a curved shape using a steel material such as H steel formed to match the shape of the structure.

Therefore, the prestressing steel material does not become eccentric and can provide the structure with a certain level of strength.

<D> Since the steel material can be formed accurately to match the shape of the structure, construction accuracy can be improved and construction management can be easily performed.

<E> Since concrete can be poured continuously, the concrete pouring height can be lowered.

Therefore, high-quality concrete can be obtained even for sloped side walls.

[Brief explanation of drawings]

Figures 1 and 2: Overall diagram of pouring equipment assembly, Figures 3~
Fig. 6: An explanatory diagram of the assembly fittings, Figs. 7 and 8: an explanatory diagram of the construction order, and Fig. 9: an explanatory diagram of the fitted state of the formwork.

Claims (1)

[Claims] 1 Steel materials bent to match the shape of a spherical or circular structure are assembled in the circumferential direction and the meridian direction inside and outside the planned pouring position of the structure, and A method of pouring concrete for spherical or circular structures, which is characterized by fitting formwork between steel members and between steel members in the outer meridian direction, and pouring concrete between the inner and outer formwork. 2. Steel materials that are bent to match the shape of a spherical or circular structure and assembled in the circumferential direction and meridian direction inside and outside of the planned contact position of the structure; steel materials in the circumferential direction and steel materials in the meridian direction A rod-shaped separator that connects the inner and outer steel members in the meridian direction at a predetermined interval, and a mold that fits between the inner meridian steel members and the outer meridian steel members. A concrete pouring device for spherical or circular structures, characterized by having a frame and being configured to pour concrete between the inner and outer formwork.