JPH0321771A - Construction method for footing using sheet mould - Google Patents

Abstract

PURPOSE:To carry out the footing construction work together with a piling work concurrently by using a sheet-form substance as the outer mould member, forming a hollow at a tube-form inner mould position in a rod reinforcement position, and incorporating the rod reinforcement and a footing after the concrete is hardened. CONSTITUTION:The part where the piling is finished is cut and excavated to expose pile heads 5 so as to set the pillar positions, and a base reinforcement 4 is placed to set an anchor 9 and the like. And on the base reinforcement 4, a cylindrical inner mould 8 with bottom is provided, and a concrete 11 is placed to make the position of the reinforcement 13 in a hollow. An outer mould made of a sheet is assembled to surround the whole body and the concrete 11 is placed in the mould. After the concrete is hardened, a pipe support 6 and round steel pipes 2 are removed to construct a footing having a hollow. Consequently, the work can be carried out concurrently with the piling work, the term of the work is reduced, and the cost can be also reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for creating a footing for transmitting the stress of a superstructure to the ground or a substructure of another company when constructing a civil engineering/building structure. It is related to. Note that the land works are the parts such as piles installed below the footing to support it.

[Conventional technology]

In recent years, a method of creating a footing has been proposed in which an outer form made of sheet is used instead of a conventional plywood form or the like. Sheet external formwork is made by rolling a suitable sheet material into a cylindrical shape and making it self-supporting using pipes, nets, etc. Compared to conventional plywood formwork, it takes less time and is easier to use even if you do not have special skills. It is characterized by being assembled into.

When using a sheet external formwork, taking advantage of the above-mentioned characteristics, for example, a pile driving craftsman excavates the area where pile driving has been completed in parallel with the piling work, arranges reinforcement, and assembles the seahu external formwork. If the footing can be created by pouring concrete, it will save a lot of time.

However, in order to do this, you need to drive a throwaway cone into each footing one by one starting from the part where the pile driving has been completed.
It is rather time-consuming as it is necessary to mark out the markings and set the column reinforcements, and at the same time to construct the reinforcing scaffolding to support the column reinforcements. It was impossible to do so.

[Problem to be solved by the invention]

The present invention aims to solve the problem that footings cannot be created until the pile driving work is completed due to the above-mentioned reasons.

[Means to solve the problem]

The present invention provides a method for creating a border that can be worked in parallel with pile driving work.

That is, a sheet material is used as the outer formwork material, and a cylindrical inner formwork with a cross section larger than the column is installed at the column reinforcement position and concrete is poured, thereby making the column reinforcement position hollow. This method of creating a footing is characterized in that after hardening, a column reinforcement is installed in the hollow portion, and concrete is poured to integrate the column reinforcement and the footing.

The method for creating a footing according to the present invention will be explained in detail below.

First, the area where pile driving has been completed is cut and excavated using a backhoe or the like to expose the pile head. At this time, the bottom of the root cut should be almost smooth.

Next, use a level etc. to determine the approximate position of the pillar, using the grid as a guide. Since the cylindrical inner formwork has a larger cross section than the pillars, it is only necessary to show the approximate position of the pillars, and there is no need for waste concrete or marking work.

Once the column position is determined, place the base reinforcement. At this time, if necessary, install anchors or the like to secure the cylindrical inner formwork.

Next, install a cylindrical inner formwork on top of the base reinforcement.

The cylindrical inner formwork must have a bottom to prevent concrete from penetrating. The previously provided anchors or the like are connected to the bottom of this cylindrical inner form by welding or using bolts or the like.

Finally, an outer formwork made of sheet is installed to surround the entire area.

In addition, any jigs necessary for fixing the cylindrical inner formwork will be installed.

Concrete is poured into the formwork assembled as described above using a pump or the like. When pouring concrete, it is advisable to provide a lid or the like on the cylindrical formwork to prevent it from entering the inner cylindrical formwork. Furthermore, if it is necessary to connect the footing and the underground sill, they may be connected by means of stabs or the like.

After the concrete hardens, if necessary, remove the cylindrical inner formwork and sheet outer formwork and backfill with excavated soil.

Since the above-mentioned work can be carried out in parallel with the pile driving work, most of the footing with the hollow part will be completed by the time the pile driving work is completed.

Column reinforcements can be set using the top surface of hardened concrete, making the work easier and improving accuracy. The footing and column are integrated by setting column reinforcements and pouring concrete into the hollow space.

Next, we will discuss the materials for formwork.

As the material for the cylindrical inner form, highly rigid materials such as expanded metal, steel pipes, PVC pipes, cardboard, corrugated pipes, and Hume pipes are preferred, but materials with low rigidity such as sheet materials, wire mesh, rubber, etc. It may also be supported with a support or the like.

The cylindrical inner formwork may be buried during concrete pouring, or may have a removable structure. If the structure is to be removable, the mold may be coated with a release agent or the like, or it may be covered with a sheet material such as foam, rubber, fabric, etc. to make it easily removable.

It is even better if the inner cylindrical mold is provided with appropriate irregularities to improve adhesion with post-cast concrete.

Examples of the sheet material for the sheet outer form include ordinary woven fabrics, nonwoven fabrics, perforated sheets, and the like. If the sheet material is semi-permeable, that is, it is made of fiber that does not permeate concrete but allows water to pass through, a moderate amount of water will be removed from the surface of the fiber cloth when concrete is poured, and the surface of the cloth will become hard and dehydrated. This is preferred because it forms a concrete layer.

The rod-shaped supports supporting this are provided at least on either the inside or outside of the sheet outer formwork, and are provided at two or more locations,
In particular, it is preferable to install the molds at about four locations on the quarter points of the cylinder in terms of stability of the formwork and construction time. The rod-shaped supports include various types of bar materials used in conventional plywood formwork construction methods, such as round pipes, square pipes, angles, square timbers, and universal gauges. A fixing material such as a string or wire is used to fix the sheet material and the rod-shaped support.

When supporting with a net-like material, attach it to the entire surface of at least one of the inside and outside sides of the sheet outer formwork.

The net-like material refers to a metal net-like material such as a crimped wire mesh, a woven wire mesh, a welded wire mesh, expanded metal, and metal lath, or a plastic net-like material. Fixing materials such as strings and wires are also used to fix the sheet material and the net-like material.

〔Example〕

FIG. 1 shows an example of the assembled formwork used in the footing construction method of the present invention. (a) is a cross-sectional view, (
b) is a plan view.

This example has a PHC pile D = 400φ x 4 footings, the width is 2m square, the height is 0.8m, and the center is 0.5m. 6
It was designed with m-square pillars.

This footing was created at the same time as the piling work, starting from the area where the piling work had been completed. First, the roots were excavated with a backhoe to expose the pile cap 5 by about 10 cm, and the bottom surface of the excavation was made almost smooth. Next, after checking the pile misalignment and head level using a level using the grid as a reference, the approximate column position was determined and marked. Then, anchors 9 for fixing the cylindrical inner formwork 8 were cast.

After marking out the outer periphery of the footing, a base reinforcement 4 was placed, and a cylindrical inner formwork was installed over it. The cylindrical inner formwork was made of expanded metal rolled into a cylindrical shape with a bottom attached. Size: outer diameter 800mm, height 700m
The bottom part was connected using the anchors and bolts installed earlier in step m. This was covered with a plastic lid 7, and the installation of the cylindrical inner formwork was completed.

Finally, an outer form made of sheet was assembled to surround the entire structure. A polypropylene woven fabric was used as the sheet material, and was wound into a cylinder to form the cylindrical body 1. This sheet material consists of 4 rigid round pipes 2
to give independence, and the round pipes are connected with pipe support 6.
It was fixed with. The round pipe and sheet material were connected with wire 3. In addition, the lower end of the sheet material was folded inward by approximately 50n++n to prevent leakage during concrete pouring.

Concrete 11 having a nominal strength of 210 kg/crl and a slump of 15 cm was poured into the formwork assembled as described above using a pump truck.

The next day, after the concrete had hardened, the pipe support and rigid round pipe were removed and used for the next formwork.

The polypropylene fabric and cylindrical inner mold were disposable.

In this way, the footing work was carried out in parallel with the pile driving work, and two days after the end of the pile driving work, the construction of the footing, which has a hollow part except for the column reinforcement part, was completely completed.

FIG. 2 is an example of a footing having a hollow portion excluding the column reinforcement portion. (a) is a cross-sectional view, and (b) is a plan view.

After that, the part where the underground beam was to be placed was cut using a backhoe, the top surface 12 of the footing was marked, the column reinforcement 13 was placed, the reinforcing steel scaffold was assembled, the reinforcement for the underground beam was placed, and the formwork was constructed. Finally, concrete was poured into the cylindrical inner formwork and the underground formwork to complete the footing according to the method of the present invention.

As a result, although material costs increased, the construction period was shortened by about one week, resulting in a significant cost reduction in total.

〔Effect of the invention〕

According to the footing construction method/method of the present invention, the footing drilling work can be performed in parallel with the pile driving work, so it is possible to significantly shorten the time compared to the conventional method.

Additionally, marking can be done on the top surface of the footing, making the work easier and improving accuracy.

[Brief explanation of drawings]

FIG. 1 is an example of an assembled formwork used in the footing construction method of the present invention. (a) is a cross-sectional view, (b)
) is a plan view. FIG. 2 is an example of a border having a hollow portion excluding the column reinforcement portion. (a) is a cross-sectional view, and (b) is a plan view. 1 is a cylindrical body made of sheet material 2 is a rigid round pipe 3 is a wire 4 is a base reinforcement 5 is a counter head 6 is a pipe support 7 is a plastic lid 8 is a cylindrical inner form frame 9 is an anchor io is a sheet The turning 11 of the material is concrete l2 is the footing, and the upper surface 13 is the column reinforcement.

Claims (1)

[Claims] In addition to using a sheet material as the outer formwork material, a cylindrical inner formwork with a cross section larger than the column is installed at the column reinforcement position, and concrete is poured to make the column reinforcement position hollow, and the concrete hardens. A method for creating a footing, which comprises: later installing column reinforcements in the hollow portion and pouring concrete to integrate the column reinforcements and the footing.