JP2000160834A - Step-up construction of concrete caisson - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assembling workability of a form and save labor and facilitate adjustment of precision for a concrete body and further, increase safety. SOLUTION: An inner form 10 formed by setting four side frame bodies 14 to a square cylindrical shape is supported by a concrete body through form-support brackets 22 fitted to anchor bolts embedded in the concrete body placed in the precedent stage, and bracket-support anchor bolts of the subsequent stage are fitted. Then, concrete in this stage is placed and after curing, form-support brackets 22 of the subsequent stage are fitted. The upper part of the side frame body 14 of the inner form 10 is tilted inward to release it, and the inner form 10 is slid up to automatically erect the form-support bracket 22 of the subsequent stage and pass the inner form 10. Thereby the form-support bracket 22 is naturally set to fall and restored so as to make it supportable. Again, the inner form 10 is moved down and mounted on the form- support bracket 22 of the subsequent stage to adjust the inner form 10 and attach a face steel plate. Further, the outer side form is assembled and the inner and outer forms are fastened together and fixed by fixing hardwares provided with separators and anchor bolts are fitted. Thereafter, concrete is placed. The above processes are repeatedly carried out up to a specified height to construct a caisson.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a concrete caisson (concrete structure used as a foundation) by a step-up method.

[0002]

2. Description of the Related Art Various methods have been proposed and implemented as a step-up method (also called a sliding foam method) for a concrete caisson. For example, it is common to assemble the side forms by lifting them one by one with a crane and mounting them on fixed brackets. However, the form assembling process requires a lot of time and has a problem in safety.

Conventionally, an inner mold has a cylindrical integral structure in which four side frames are arranged in front, rear, left and right and haunch forms are attached to haunch portions between the side frames (four corners). The inner formwork is lifted by a crane on a fixed bracket attached to the concrete structure, installed at the required position, the outer formwork and the inner formwork are positioned and fixed by the separator, and concrete is struck between the inner and outer formworks. After the concrete is solidified, the inner and outer forms are separated from the concrete surface and slid up to the next level, and the above steps are repeated in order to construct a caisson of the required height.

[0004]

By the way, in the above-mentioned prior art, it takes time to correct the error of the cylindrical inner form, and it takes much time for the form assembling work. Since the assembling is performed sequentially from the bottom, it takes a long time to assemble the scaffold, and there are problems such as safety during the assembling of the scaffold, and a large cavity (opening) surrounded by four inner scaffolds after the completion of the assembling.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and has as its object to improve the formwork assembling operability, save labor, and improve the accuracy of concrete skeleton (thickness, thickness,
It is an object of the present invention to provide a concrete caisson step-up construction method capable of facilitating adjustment of dimensions) and improving safety.

[0006]

According to the present invention, the following technical measures are taken to achieve the above object. That is,
The present invention is a concrete caisson step-up construction method including the following steps. The four side frames are arranged in the shape of a rectangular tube facing the front, rear, left and right, and the inner formwork assembled in a box so as to be movable in and out of each other is buried in the solidified concrete body cast in the previous stage. A first step of mounting on the form support bracket attached to the anchor bolts, and fixing the inner forms to each other or to the inner form and the outer form at a predetermined interval with a fixing metal provided with a separator, and in the next step A second step of arranging the anchor bolts for mounting the form supporting bracket, a third step of slidably mounting the face iron plate to the vertical haunch portions at the four corners of the inner form with respect to the side frame body, A fourth step of placing concrete between the frames, a fifth step of assembling the rebar or steel frame of the next step, and a sixth step of attaching the next step of the form support bracket to the anchor bolt after the concrete has been cast. ,each A seventh step of separating the inner formwork and the cast concrete surface so that the upper portions of the frame bodies are respectively inclined inwardly toward the opposite side, and supporting the formwork above the next step position by using a crane or other lifting means. An eighth step of moving the bracket under the guide of the guide rollers and lowering the bracket when the bracket is in a state in which the frame can be supported, and placing the bracket on the bracket; and a ninth step of disposing the outer mold so as to face the inner mold.

According to this structure, since the inner formwork is assembled in a box in advance, it can be lifted and slid by a lifting means such as a crane and moved to the next stage. At this time, each side frame body lifts up the form support bracket frame support portion at the next stage, and is guided by the guide roller to smoothly move up, so that the frame support portion of the bracket naturally falls down. The mold is supported.

For this reason, the bracket can be placed on the frame support of the bracket only by lowering the inner mold, so that the labor for installing the mold can be greatly reduced, and the workability is improved and the work time is shortened. I can do it. In addition, by using the form supporting brat, when the inner form is lifted, work below the inner form is not required at all, and extremely safe work is possible.

Further, since the face iron plate of the vertical haunch portion can be moved with respect to the side frame, adjustment of the accuracy of the concrete frame, that is, the space between the inner and outer forms (concrete frame thickness), dimensions, etc., according to the frame. It can be done easily. Further, in the sixth step, in the sixth step, the form support bracket at the next stage is provided on an inner scaffold provided inside the inner form,
It is characterized in that each side frame is attached to an anchor bolt through a small window provided corresponding to the anchor bolt embedding position.

In this case, since the scaffold is attached to each side frame inside the inner mold, various operations such as adjusting the dimensions of the mold, attaching the mold support bracket, attaching the face iron plate, and releasing the mold are easy. It can be performed safely and efficiently. Further, the arrangement of the anchor bolts and the attachment of the form support bracket can be easily performed from the small windows of each side frame body,
Various workability can be greatly improved.

In the present invention, a top end scaffold covering an upper opening of the form is provided at the upper end of the inner form so as to be partially openable and closable, and the fourth and fifth steps are performed on the top end scaffold. It is characterized in that it also performs a step-up operation of the outer formwork. In this case, since the upper opening of the inner formwork is closed by the top scaffold, and each side frame can move inward and outward with respect to the top scaffold, the upper side frame body is tilted inward. It can be separated from the concrete surface and can be restored and adjusted, and a part of the top scaffold can be opened and closed to enter and exit the inner formwork, so that various operations on the top scaffold can be performed safely and efficiently. It is not necessary to provide a separate means for preventing the worker from falling.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a concrete caisson 1 employing an embodiment of a step-up construction method according to the present invention has an outer wall 2 divided into a plurality of sections by vertical and horizontal bulkheads 3 and 4 in plan view, and is constructed in five stages. Is done.

Then, the inner mold 5 used in the first stage
Is different from an inner mold 10 to be described later used in the second stage or more, as shown in FIG. 2, a haunch form 8 forming a haunch 7A of the bottom wall 7 (bottom plate) is provided at the lower end. And
Along with the first-stage outer formwork 6, it is configured not to slide. Although not shown, a face iron plate that forms the vertical haunch 9 shown in FIG. 1 is attached to the inner formwork 5.

As shown in FIG. 2, the inner and outer mold frames 5 and 6 are made of a plywood side mold plate 11, a horizontal crosspiece 12, and a vertical beam member 13 (also referred to as a shuttering beam) made of a molded steel material.
It is manufactured to the required size. In addition, the side frame 14 and the outer mold 15 constituting the inner mold 10 used in the second stage or more are similar to the inner / outer frames 5 and 6 in that the plywood side mold 11 and the crosspiece 12 are provided. , Vertical beam members 13 and the like.

Then, the inner and outer molds 5, 10, 6, 15
Are temporarily fixed with a certain degree of precision, respectively, and then, as shown in FIG.
6 is tightened and fixed at a required interval T (concrete wall thickness). The fixing bracket 16 includes a separator 17 shown in FIG. 4 and two long nuts 18 having cones (cone portions) 18A attached to both ends of the separator 17 (FIG. 5).
), A bolt 19 (form tie) screwed to both nuts 18, a washer 20, and a nut 21.

In the first stage, the inner and outer molds 5, 6
An anchor bolt 23 for mounting the form support bracket 22 is buried in the upper portion therebetween (see FIG. 2). The outer diameter of the long nut 18 is smaller than the hole diameter for passing the bolt 19 through the mold because the outer diameter of the nut 17 is inserted through the separator 17 from outside the molds 5, 6, 10, and 15. Approximately two-thirds of the entire length, the dimensional accuracy 3 of the mold interval T can be improved.

When the mold is removed from the mold, the long nut 18 is removed from the separator 17 with a dedicated wrench, and a waterproof mortar is buried in a hole formed thereafter to prevent water leakage from the separator 17. The form support bracket 22
As shown in FIG. 6, a mounting base 24 having a groove shape in cross section having a bolt hole 25 in a mounting part 24A to a concrete surface, and a side plate 24B provided at an upper end of the mounting base 24.
A form-mounting bracket body 27 having a base end inserted therebetween and rotatably mounted by a horizontal support shaft 26 only between a horizontal state (see FIG. 6) and a vertical state (see FIG. 7); At the lower end of the pedestal 24, a guide roller 29 is rotatably mounted between the side plates 24B by a shaft 28 parallel to the support shaft 26. The lower edge of the side plate 24B of the mounting pedestal 24 is a downwardly inclined surface.

The bracket 22 is mounted on the concrete wall 2.
4 are removably attached to the anchor bolts 23 buried in Nos. 1 to 4 by using the nut holes 25 by using the bolt holes 25. The bracket body 27 is
The position of the support shaft 26 is determined so as to always return to the horizontal state shown in FIG. 6 by its own weight, and the main body base end surface 27A
7 (see FIG. 7) comes into contact with the inner surface of the mounting portion 24A.

The bracket main body 27 is flipped up by the side surface template 11 of the form and made substantially vertical. When the bracket body 27 separates from the side surface template 11, it is rotated downward by its own weight and returns to a horizontal state. When the construction of the first stage concrete structure is completed by the conventional construction method, as shown in FIG.
2 are attached, the outer scaffold 31 is assembled, and although not shown, a reinforcing bar (or a steel frame) is assembled, and then the inner formwork 10 uses the suspension frame 32 between the vertical and horizontal bulkheads 3 and 4 using a crane. And is placed on the form support bracket 22.

Inner form 1 used upward from the second stage
9, four side frame members 14 arranged in a rectangular tube shape (box shape) facing each other in the front-rear and left-right directions as shown in FIGS. The face iron plate 33 forming the vertical haunch portions 9 disposed between the side frame members 14, that is, the four corners, and the inner plate 33 which is attached to the vertical beam member 14 of the side frame member 14 on the side opposite to the cross bar 12 The main structure is composed of a scaffold 34 and a flat top end scaffold 35 that covers an upper opening surrounded by the vertical beam 13 and the side frame 14.

The side frame 14 is, as shown in FIG.
The longitudinal beams 13 are connected to each other by tie rods 36 at the front, rear, left and right ends, and jack bases 37, 37 are provided at both ends in order to maintain the facing intervals.
Are supported by support pipes 38, 38 having a support pipe 38 interposed therebetween. Note that the horizontal hole 39 provided in the vertical beam member 13 has a structure shown in FIG.
As shown in FIG. 10, the square pipe 40 is inserted horizontally in the upper and lower portions and fixed by the wedge bolt 41, and the jack base 37 is supported in contact with the square pipe 40 or the vertical beam member 13 (see FIG. 10). .

Therefore, by loosening the jack base 37, the side frame 14 can be inclined inwardly to the opposite side, and by tightening the jack base 37, the square pipe 40 is protruded and the side frame 14 Can be returned to a vertical shape. The tie rod 36 and the jack base 37 adjust the spacing of the side mold plates 11 and 11 between the adjacent inner mold frame 10 or the outer mold frame 15 that determines the concrete wall thickness T facing each side frame body 14. And easily.

In FIG. 10, only one set of the tie rods 36 and the support pipes 38 are shown in the front, rear, left and right, but at least two sets are respectively provided in the front, rear, left and right, and two sets of the top and bottom are respectively provided.
There are a total of eight sets. As shown in FIGS. 9 and 11, the inner scaffold 34 has an upper and lower two-stage scaffold plate support member 42, one end of which is fixed to the longitudinal beam member 13 at right angles and in parallel.
43, and the longitudinal beam 13
The vertical members 44 are fixed in parallel with each other, the horizontal members 45 connecting the vertical members 44 to each other, and the scaffold plates 46 and 47, and the scaffold plates 46 and 47 have a corridor shape. Then, the ladder 62 is moved so that it can move to the upper and lower scaffold plates 46 and 47.
Is installed.

Therefore, most of the work in the inner formwork 10 can be performed on the inner scaffold 34, and it is not necessary to perform the assembling work for each stage. Can be greatly reduced. In addition, a safety net 48 for preventing fall is fixedly extended on the lower side of the inner scaffold 34 at four ends thereof at a lower end portion of the vertical beam member 13 to improve work safety.

At both ends of each side bar 12 of the side frame 14,
As shown in FIGS. 9 and 10, a triangular face iron plate contact member 49 in a plan view is attached. And the face iron plate 33
12 is brought into contact with the contact member 49 from the outside, and at both the upper and lower end portions and the middle portion, as shown in FIG. 12, both ends are directly applied to the adjacent cross bar 12 (or via a triangular receiving member). It is detachably attached to a receiving member 50 supported in a bridge-like manner via a fastener (for example, a flat iron wire, a bolt, a nut, etc.) 51.

As described above, since the face iron plate 33 and the side frame body 14 are attached so as to be relatively movable in the horizontal direction via the contact portion 49, the outer mold 15 at each stage is provided.
It is easy to adjust the distance (wall thickness T) between the side template 11 or the side template 14 and the side template 11, and when the side frames 14 of the inner mold 10 incline and move inward each other. By loosening or removing the fastener 51, the work can be easily performed without restraint.

The top scaffold 35 is, as shown in FIG.
It is placed so as to straddle the top end of each vertical beam member 13, and allows the inward tilt and movement of each side frame 14. Then, as shown in FIG. 13, the top end scaffold 35 is made of a rectangular outer frame 52 and a cross-girder frame 5 assembled with a channel steel.
3 and a plurality of scaffold plates 55 laid on the framework 54 to form a flat plate.

The scaffolding plate 55 is fixed to the frame assembly 54 except for two pieces 55A and 55B on both left and right sides, and the two left and right pieces are connected to each other to form an opening / closing door 56. (Or the outer frame body 52) by a hinge 57, so that the door 56 can be opened so as to be able to enter and exit the inner formwork 10. As shown in FIGS. 8 and 14, small windows 58 for attaching a form support bracket are provided at the upper left and right ends of the side surface template 11, respectively.

Next, the caisson construction process from the second stage to the fifth stage will be described with reference to FIGS. 8 and 14 to 28. After the inner mold 10 configured as described above is cleaned on the ground and coated with a release agent, it is lifted by the hanging frame 32 via the hanging wires 59 attached to the vertical beam members 13 as shown in FIG. As shown in FIG. 8, as a first step, the caisson bottom slabs 3-1, 1-3, which are constructed in the first stage, are suspended from hanging hooks 60 such as cranes.
It is mounted on the form support bracket 22 attached to 4-1. Although not shown, a frame reinforcing bar of the second stage is assembled on the caisson bottom slab constructed in the first stage, and the form support bracket 22 is attached.

As shown in FIG. 8, when the inner form 10 is carried in and placed on the form supporting bracket 22, the outer form 15 is carried to a predetermined position by a crane, and the form supporting Installed on top. Then, the inner and outer molds 10 and 11 and the inner mold 10 are separated from each other by the separator 1.
Small window 5 fixed to side template 11
8, the bracket mounting anchor bolt 23 is mounted (second step).

Subsequently, face iron plates 33 to be vertical haunch portions are fixed to the four corners of the inner formwork 10 from above the inner scaffold 34 with the fasteners 51 (third step), and the formwork assembling work is completed. It is similar to the state shown. Then, concrete is driven between the inner and outer forms 10 and 15 and between the inner forms 10 on each top scaffold 35 (fourth step—see FIG. 28). When the second-stage concrete walls 2-2, 3-2, and 4-2 solidify, the next level, that is, the third-stage rebar 61 is assembled by the operator on the top scaffold 35 as shown in FIG. (Fifth step).

Subsequently, as shown in FIG.
5 is opened, and the worker gets down on the inner scaffold 34 in the inner formwork 10. Then, on the inner scaffold 34, the operator moves the form support bracket 22 from the small window 58 of the side template 11.
However, as shown in FIG. 18 (showing a state in which the crown scaffold 35 has been removed, the crown scaffold 35 is actually mounted),
Each is attached to the anchor bolt 23 embedded in the skeleton (sixth step).

At the same time, the bolts 19 attached to the molds 10 and 15 are removed together with the long nuts 18, and the fasteners 51 of the face iron plate 33 and the jack base 37 are tightened so that the upper portion of the rear frame 14 is turned inward. By tilting, the side plate template 11 and the cast concrete surface are separated (seventh step—see FIG. 23). Subsequently, as shown in FIG. 19, FIG. 20, and FIG.
0 is lifted with a crane. At this time, each side frame 14 rises while being inclined inward as shown in FIG.

When the side mold plate 11 of the side frame body 14 pushes up the frame mounting bracket main body 27 of the form support bracket 22 and notifies the bracket 22 with the rise of the inner mold 10, FIG. As shown in FIG. 24, it becomes parallel to the concrete wall surfaces 3-2, 4-2, and 2-2, and is guided by the guide rollers 29 to smoothly rise. Inner formwork 10
As shown in FIG. 25, by lowering the lower end of the side mold plate 11 from the form support bracket 22 (upper side in FIG. 25) to slightly above the length of the bracket body 27, the bracket body 27 is From the state shown by the middle dotted line, it naturally falls back to the horizontal state shown by the solid line and recovers, and the mold can be supported. Therefore, the inner mold 10 is lowered again and placed on the main body 27 of the mold support bracket 22. FIG. 22
(8th process).

Subsequently, on the top end scaffold 35 of the inner form 10, the worker adjusts the inner form 10 while ensuring the safety of the body with the master rope 63 stretched above the form, Adjustment work of the jack base 37, the tie rod 36 and the like is also performed inside the formwork 10. At this time, since the inner formwork 10 is placed on the formwork support bracket 22, there is no dangerous work under the suspended load, and the safety net 48 is provided inside.
It is safe because it is stretched.

Although the reinforcing bar 61 is not shown in FIGS. 19 to 25, it is already assembled as shown in FIGS. Then, the second to eighth steps are repeated. First, the inner molds 10 are
And the like, and the anchor bolts 23 are attached (second step), and the face iron plate 33 is attached to the adjacent side frame 14.
It is fastened and fixed in between (third step).

In this manner, the third stage inner mold 10
26, the outer formwork 15 is once lifted up by the crane using the hanging wire 64 and the chain block 65 as shown in FIG.
Clean the surface of the side template 11 and apply a release agent on it,
When the maintenance is completed, lower the outer formwork 15 again,
It is placed on the form support bracket 22 already attached (ninth step).

Next, as shown in FIG. 27, the outer mold 15 and the inner mold 10 are fastened and fixed to each other by a separator 17, a long nut 18, and a bolt 19, and an anchor bolt 23 is attached. Two steps), the form setting work is completed, and the state shown in FIG. 15 is obtained. Subsequently, as shown in FIG. 28, the space between the inner and outer
After the concrete is poured between each other (fourth step), the concrete is cured, and the construction of the third stage is completed.

By repeating the second to ninth steps in the fourth and fifth steps (or as many times as necessary), the desired caisson is stacked up to the height. In addition,
Since the raising or sliding work of the inner formwork 10 is sequentially performed from the formwork 10 located at the corner of the caisson to the adjacent side, an operator who rides on the formwork 10 for the formwork slide setting work needs to be lifted. Since the work is performed while moving onto the top end scaffold 35 adjacent to the formed form 10 next to the formed form 10, there is no need to go up and down on the form 10 and, therefore, a ladder or the like for raising and lowering the worker is unnecessary. .

The caisson 1 in which the concrete has been poured in the fifth stage enters curing, and when curing is completed, the inner and outer forms 10 and 15 are removed and the caisson 1 is launched. According to the above-described embodiment of the present invention, the front, rear, left and right side frame members 14 are assembled into a rectangular tube to form the inner formwork 10. Therefore, the inner frame 10 is lifted by a crane or other heavy equipment and arranged at required locations. It is possible to improve work efficiency by saving labor and shortening time of construction.

Further, the face iron plate 3 forming the vertical haunch 9
3 is movably attached to the side frame body 14, so that it is easy to adjust the accuracy of the frame body such as the distance T between the side frame bodies 14 and the outer formwork 15 and the like. The release and ascending slide by tilting can be performed easily and smoothly. Since the form support bracket 22 having the guide roller 29 and the up-and-down body 27 is employed, the form can be smoothly slid, and the bracket body 27 can naturally fall down and return to support the form. State. Therefore, there is no work under hanging loads such as the inner formwork 10 when the formwork 10 is lifted, and safe work can be performed.

Further, since the upper opening of the inner formwork 10 is closed and opened by the top end scaffold 35 provided with the opening / closing door 56, the rebar 61 assembling work, concrete placing work and the like can be performed safely and efficiently. The work in the inner formwork 10 is safe. Moreover, since the inner scaffold 34 fixed to the longitudinal beam 13 is provided in the inner formwork 10 on all four sides,
Adjustment and release work in the inner formwork 10 and the anchor bolt 2
3. The work of mounting the form support bracket 22, the face iron plate 33 and the like can be performed easily and safely.

Further, according to the step-up method of this embodiment, the number of times the inner formwork 10 is diverted can be increased, so that the number of times the formwork material is discarded can be reduced and the problem of industrial waste can be reduced. The reduction of the formwork material can contribute to environmental problems, and contribute to cost reduction and resource saving. The present invention is not limited to the above embodiment. For example, the small window 58 is provided with an opening / closing door so that the small window 58 can be easily closed, and the opening / closing door 56 of the top end scaffold 35 is specially provided. Even without it (the hinge 57 is not provided), the design can be changed as appropriate, such as removing or attaching the two scaffold plates 55, and without stepping up the outer formwork 15.

[0044]

As described above, according to the caisson step-up construction method according to the present invention, the inner form formed by assembling the four side frames is integrally slid,
The side frame body is supported by the form support bracket, and each side frame body can move relative to the face iron plate. This facilitates the adjustment of the caisson body accuracy as well as shortening the construction period by improving the workability of the formwork and saving labor. Thus, it is possible to improve work safety and the like.

Further, since the anchor bolt and the form support bracket are attached through the small windows provided in the side frame, the work can be performed easily and efficiently. Further, since the inner formwork is provided with the inner scaffold and the top scaffold, the scaffold assembling and disassembling operations can be greatly reduced, and the work efficiency can be secured as well as the work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a concrete caisson constructed according to the present invention.

FIG. 2 is a sectional view showing inner and outer molds in a first stage of the embodiment.

FIG. 3 is a cross-sectional view showing an example of a fastening and fixing structure of the inner and outer molds in the embodiment.

FIG. 4 is an enlarged perspective view showing a formwork fastening fixture used in the embodiment.

FIG. 5 is an enlarged perspective view of a long nut constituting the fixing bracket.

FIG. 6 is a perspective view of a form support bracket used in the embodiment.

FIG. 7 is an explanatory view of the operation of the same frame supporting bracket.

FIG. 8 is an explanatory diagram of a state of loading of the inner formwork at the second stage or higher in the embodiment.

FIG. 9 is a cross-sectional view of the inner formwork in the embodiment.

FIG. 10 is a plan view showing a structure for fastening and fixing the inner formwork.

FIG. 11 is a plan view showing an inner scaffold mounting structure of the inner formwork.

FIG. 12 is a plan view of a main part showing an example of a mounting structure of a face iron plate.

FIG. 13 is a plan view of the top scaffold in the embodiment.

FIG. 14 is a perspective view showing a lifted state of the inner formwork in the embodiment.

FIG. 15 is a perspective view showing a completed state of the mold assembly in the third stage in the embodiment.

FIG. 16 is a perspective view showing an iron wire assembling operation state on the top end scaffold.

FIG. 17 is a perspective view showing a state in which an opening / closing door of the top scaffold is opened and an operator enters the inside formwork.

FIG. 18 is a perspective view showing a working state in the inner formwork.

FIG. 19 is a perspective view illustrating a state in which the inner mold starts to slide upward.

FIG. 20 is a perspective view showing a state in which the inner mold is being slid up.

FIG. 21 is a perspective view showing the raised state of the inner mold.

FIG. 22 is a perspective view showing a mold adjusting operation state after completion of the upward sliding of the inner mold.

FIG. 23 is a cross-sectional view illustrating a release state of the inner mold according to the embodiment due to tilting of the side frame body.

FIG. 24 is a cross-sectional view showing a state in which the inner frame is being slid up.

FIG. 25 is a cross-sectional view showing a state in which the inner formwork has been lifted and then started to lower again.

FIG. 26 is a perspective view showing a step-up operation state of the outer formwork on the top scaffold in the embodiment.

FIG. 27 is a perspective view showing an inner / outer formwork tightening adjustment operation state on the inner formwork inner scaffold.

FIG. 28 is a perspective view showing a concrete placing operation state on the top scaffold in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete caisson 9 Vertical haunch part 10 Inner formwork 11 Side form plate 12 Side beam 13 Vertical beam material 14 Side frame 15 Outer formwork 16 Fixture 17 Separator 22 Formwork support bracket 23 Anchor bolt 27 Bracket body 29 Guide roller 33 Face iron 34 Inner scaffold 35 Top end scaffold 55 Scaffolding board 56 Opening door 58 Small window 61 Reinforcing bar

Claims (3)

[Claims] 1. An inner form formed by arranging four side frames in a rectangular tube shape facing each other in the front-rear and left-right directions and having a box assembled so as to be movable in and out of each other. A first step of mounting on a form support bracket attached to anchor bolts embedded in the concrete skeleton, and fixing the inner forms to each other or to the inner form and the outer form at predetermined intervals by a fixing metal provided with a separator. And a second step of arranging the anchor bolts for mounting the form support bracket in the next stage, and a third step of mounting a face iron plate on the vertical haunch portions at the four corners of the inner form so as to be slidable relative to the side frame. A fourth step of placing concrete between the opposing forms; a fifth step of assembling a reinforcing bar or a steel frame of the next step; and after setting concrete solidification, the next step of the form supporting bracket is attached to the anchor bolt. Mounting A sixth step, a seventh step of separating the inner formwork and the cast concrete surface such that the upper portions of the side frame bodies are respectively inclined inwardly to the opposite side, and a step above the next step position by the weighting means for the inner formwork An eighth step of moving the guide under the guidance of the form support bracket and lowering the bracket when the bracket is in a form supportable state and mounting the bracket on the bracket; and a ninth step of disposing the outer form so as to face the inner form. A concrete caisson step-up construction method comprising: 2. In the sixth step, the form support bracket of the next stage is provided on an inner scaffold provided inside the inner form,
2. The step-up construction method for a concrete caisson according to claim 1, wherein a small window provided on each side frame body corresponding to the anchor bolt embedding position is attached to the anchor bolt. 3. A top end scaffold covering an upper opening of the formwork is provided at an upper end of the inner formwork so as to be partially openable and closable, performing the fourth and fifth steps on the top end scaffold, and The step-up construction method for a concrete caisson according to claim 1 or 2, wherein a step-up operation of the formwork is also performed.