JP7549541B2 - Construction method of CFT pillars - Google Patents

Description

The present invention relates to a method for constructing CFT columns that construct a lower CFT column and an upper CFT column that are continuous in the vertical direction.

As a construction method for the above-mentioned CFT columns, a construction method is known in which a lower CFT column and an upper CFT column are arranged vertically, the upper end of the lower CFT column is welded to the lower end of the upper CFT column, and then a compressive force transmission material is filled in the gap between the upper end surface of the lower CFT column and the lower end surface of the upper CFT column, which is then hardened to join the lower CFT column and the upper CFT column, thereby constructing a lower CFT column and an upper CFT column that are continuous in the vertical direction (see, for example, Patent Document 1).

In the construction method described in Patent Document 1, the lower steel pipe of the lower CFT column and the upper steel pipe of the upper CFT column are filled with concrete beforehand, and then the lower CFT column and the upper CFT column are arranged one above the other.

In contrast, another construction method is known in which the lower steel pipe of the lower CFT column and the upper steel pipe of the upper CFT column are arranged in a vertically continuous state, and then concrete is filled inside the lower steel pipe and the upper steel pipe to construct a vertically continuous lower CFT column and upper CFT column (see, for example, Patent Document 2).

In the construction method described in Patent Document 2, the lower steel pipe and the upper steel pipe are joined in a state in which their interiors are connected to each other, a concrete supply pipe is connected to an injection port provided in the lower steel pipe, and concrete is injected from the bottom to the top into the lower steel pipe and the upper steel pipe, filling the insides of the lower steel pipe and the upper steel pipe with concrete.

Patent No. 3322652 Patent No. 3518334

In both of the construction methods described in Patent Documents 1 and 2, when constructing the lower CFT column and the upper CFT column that are continuous in the vertical direction, the construction order is such that the lower CFT column is constructed first, and then the upper CFT column is constructed.

However, depending on various construction conditions, for example, the need to ensure a clear route for construction vehicles to move around the installation site of the lower CFT pillars, the lower CFT pillars that were installed earlier can get in the way, making it impossible to secure construction space and making it impossible to carry out other construction work, so a solution is needed.

In view of this situation, the main objective of the present invention is to provide a method for constructing CFT columns that can flexibly respond to situations in which it is not possible to construct the lower CFT column first, and the upper CFT column, when constructing the lower CFT column and the upper CFT column that are continuous in the vertical direction.

The first characteristic configuration of the present invention is a construction method for a CFT column that constructs a lower CFT column and an upper CFT column that are continuous in the vertical direction,
The upper steel pipe is installed in a state where the lower CFT column installation space and the joint space are secured on the lower side, and the upper steel pipe is filled with concrete to carry out the preliminary process of constructing the upper CFT column in advance.
Then, a lower steel pipe is installed in the lower CFT installation space, concrete is filled inside the lower steel pipe to construct the lower CFT column, and a subsequent process is carried out to join the lower end of the upper CFT column and the upper end of the lower CFT column in the joining space.

According to this configuration, the preceding process is performed first, so that not only is a joining space secured below the upper CFT column, but also a lower CFT column installation space is secured, so that the upper CFT column can be constructed while securing these spaces as construction space such as the traffic lines of construction transport vehicles, etc. Then, by performing the following process after the preceding process, the lower CFT is constructed in the lower column installation space, and the upper CFT column and the lower CFT column are joined in the joining space, so that the lower CFT column and the upper CFT column that are continuous in the vertical direction can be constructed. In this way, by performing the preceding process and the following process in sequence, construction space such as the traffic lines of construction transport vehicles, etc. can be secured, and the lower CFT column and the upper CFT column that are continuous in the vertical direction can be suitably constructed while other construction work can be performed.

The second characteristic configuration of the present invention is that in the subsequent process, a concrete filling process is carried out in which concrete is filled into the lower steel pipe and the joint space to construct the lower CFT column and join the lower end of the upper CFT column to the upper end of the lower CFT column,
In the concrete filling step, a standard filling space is secured in advance between the lower end of the upper steel pipe and the upper end of the lower steel pipe, which is capable of filling a standard amount of concrete based on a standard filling amount when a standard filling operation is performed, and a first pressing step is performed to press and fill the concrete until it reaches the standard filling space,
Thereafter, when the concrete reaches the reference filling space, a second pressing step is performed in which the concrete is pressed into the reference filling space by a reference filling operation.

When filling the lower steel pipe and the joint space with concrete, if the amount of concrete filled or the pressure applied is too high, it can cause problems such as the steel pipe swelling. Conversely, if the amount of concrete filled is too low, the amount of grout and other fillers that need to be injected to fill the gaps will increase, resulting in disadvantages in terms of workability, such as increased effort.

Therefore, according to this configuration, when filling the lower steel pipe and the joint space with concrete, the first pressing step is first performed, which allows the concrete to be smoothly pressed in and filled until it reaches the standard filling space. After that, the second pressing step is performed, and by simply performing the standard filling operation, the standard filling amount of concrete can be filled into the standard filling space, and concrete can be appropriately filled into the standard filling space.

In this way, in the first pressing step, it is only necessary to monitor whether the filling amount of concrete reaches the standard filling space, and in the second pressing step, it is only necessary to simply perform the standard filling operation, so that effective improvements can be made in terms of workability. Moreover, since the standard filling amount when the standard filling operation is performed can be known in advance, by setting the size of the standard filling space based on the previously known standard filling amount, it is possible to eliminate gaps formed in the standard filling space or to make the size of the gap smaller. Thus, it is possible to eliminate gaps formed in the standard filling space or to make the gap smaller, and it is possible to eliminate the need for filler such as grout to fill the gap or to reduce the amount of filler injected, which also improves workability.

The third characteristic feature of the present invention is that it is provided with a first confirmation hole for checking whether the concrete has reached the reference filling space, and a second confirmation hole for injecting the filler into the reference filling space and for checking whether the filler has been injected into the gap in the reference filling space.

According to this configuration, by using the first confirmation hole in the first pressing step, it is possible to easily confirm whether the concrete has reached the standard filling space, and concrete can be appropriately filled until it reaches the standard filling space without filling the amount of concrete too much or too little. Furthermore, by using the second confirmation hole, an appropriate amount of grout or other filler can be injected into the gap in the standard filling space. This allows an appropriate amount of concrete to be filled into the lower steel pipe and the joint space, without filling the amount of concrete too much or too little.

The fourth characteristic feature of the present invention is that in the subsequent process, the joint extending downward from the lower end of the upper CFT column is welded to the upper end of the lower steel pipe, and the welding process is performed to cover the joint space with the joint, and then the concrete filling process is performed.

According to this configuration, by performing the welding joining process, the lower end of the upper CFT column and the upper end of the lower steel pipe can be appropriately welded together using the joint. Moreover, since the joint extends downward from the lower end of the upper CFT column, when welding the joint and the upper end of the lower steel pipe, it is possible to prevent heat from being applied to the concrete filled in the lower CFT column, and appropriately prevent adverse effects on the concrete.

A diagram showing continuous CFT columns in the vertical direction A diagram showing the preceding process Diagram showing the welding process FIG. 1 is a diagram showing a first press-in step. FIG. 2 shows a second press-in process. Diagram showing the gap filling process

An embodiment of a construction method for a CFT column according to the present invention will be described with reference to the drawings.
This CFT column construction method is for constructing a lower CFT column 1 and an upper CFT column 2 that are continuous in the vertical direction, as shown in Fig. 1. The lower CFT column 1 is formed by filling the hollow space inside a lower steel pipe 11 with concrete 12, and the upper CFT column 2 is formed by filling the hollow space inside an upper steel pipe 21 with concrete 22. The lower steel pipe 11 and the upper steel pipe 21 have the same cross-sectional shape, for example, rectangular or circular.

When constructing such CFT columns, it is usually considered that the construction order is to construct the lower CFT column 1 first, followed by the upper CFT column 2. However, depending on various construction conditions, for example, the need to ensure a traffic route for construction transport vehicles at the installation location of the lower CFT column 1, the lower CFT column 1 that was constructed first may get in the way, making it impossible to secure construction space and making it impossible to carry out other construction work.

Therefore, in this embodiment, a preceding process is carried out in which the upper CFT column 2 is constructed first, and then a succeeding process is carried out in which the upper steel pipe 21 and the lower steel pipe 11 are joined to construct the lower CFT column 1.

In buildings, etc., multiple CFT column assemblies are provided with a horizontal gap between them, each consisting of a lower CFT column 1 and an upper CFT column 2 that are continuous in the vertical direction. Therefore, in order to secure work space, the target CFT column assembly is selected from among the multiple CFT column assemblies, and the above-mentioned preceding and following processes are carried out in sequence when constructing the selected CFT column assembly. The target CFT column assembly may be one set or multiple sets, and the target CFT column assembly can be selected depending on the size and location of the work space to be secured.

The preceding and following processes are explained below, but we will explain the case of constructing a set of CFT columns consisting of a lower CFT column 1 and an upper CFT column 2 that are continuous in the vertical direction, as shown in Figure 1.

In the preceding process, as shown in Figure 2, the upper steel pipe 21 is installed while securing the lower CFT column installation space 3 and the joint space 4 on the lower side, and the upper steel pipe 21 is filled with concrete 22 to construct the upper CFT column 2 in advance.

At a position corresponding to the lower end of the upper steel pipe 21, a bottom wall portion 23 is provided that closes the internal space with a plate or the like. The upper steel pipe 21 is supported by temporary materials 31 such as trusses connected to the building frame, etc., and the lower CFT column installation space 3 and the joint space 4 are secured in a vertically aligned state between the bottom wall portion 23 of the upper steel pipe 21 and the installation surface 5 such as the ground on which the lower CFT column 1 is installed. The concrete 22 is filled into the interior of the upper steel pipe 21 by a drop-in method in which the concrete 22 is poured into the interior of the upper steel pipe 21 from its upper end using a tremie pipe or flexible hose, etc.

In the subsequent process, first, as shown in FIG. 3, a welding joining process is performed in which the lower end of the upper steel pipe 21 and the upper end of the lower steel pipe 11 are welded together, and then, as shown in FIG. 4 and FIG. 5, a concrete filling process is performed in which concrete 12 is filled inside the lower steel pipe 11 and into the joint space 4.

In the welding process, as shown in FIG. 3, the joint 41 (see FIG. 2) extending downward from the lower end of the upper steel pipe 21 is welded to the upper end of the lower steel pipe 11 so that the joint 41 covers the joint space 4. The joint 41 is formed in a hollow shape with the same cross-sectional shape as the upper steel pipe 21, and is composed of a plate-like body extending downward while covering the inside periphery. The upper end of the lower steel pipe 11 is provided with a backing part 42 extending upward, and the upper end of the lower steel pipe 11 and the lower end of the joint 41 are welded together with the backing part 42 abutting against the inner wall of the joint 41.

In the concrete filling process, as shown in Figures 4 and 5, concrete 12 is filled into the lower steel pipe 11 and the joint space 4, and the lower CFT column 1 is constructed and the lower end of the upper CFT column 2 is joined to the upper end of the lower CFT column 1. At this time, concrete 12 is filled into the lower steel pipe 11 and the joint space 4 by a pressurization method in which a pressure feed pipe 47 is connected to a pressure inlet 46 at the base of the lower steel pipe 11, and concrete 12 is pressed in from a concrete pump such as a pump truck through the pressure feed pipe 47 and guide pipe 48, as shown by the arrows in Figures 4 and 5.

As shown in FIG. 3, a standard filling space 43 is secured in advance in the upper end portion of the upper steel pipe 21 (the portion adjacent to the bottom wall portion 23 of the upper steel pipe 21) in the joint space 4. This standard filling space 43 is set as a space that can be filled with more concrete 12 than the standard filling amount when a standard filling operation is performed by the pressing method. The standard filling operation is, for example, an operation of pressing in concrete 12 once with a concrete pump (one push). The standard filling amount when the standard filling operation is performed can be obtained in advance by experiment, the capacity of the concrete pump, etc.

The size of the standard filling space 43 is therefore set to the standard filling amount plus the amount of filler 46 (e.g., grout) used to fill the gaps 47, so that some gaps 47 (see FIG. 5) will be created when the standard filling amount of concrete 12 is filled into the standard filling space 43. In this way, the size of the standard filling space 43 is set based on the standard filling amount determined in advance, so that the amount of filler 46 to be filled can be prevented from becoming too large, and the operation for filling the concrete 12 can be improved by simply performing the standard filling operation.

As shown in Fig. 3, the joint 41 in the joint space 4 has a first confirmation hole 44 at a position corresponding to the lower end of the reference filling space 43 to confirm whether the concrete 12 has reached the reference filling space 43. As shown in Fig. 4, the concrete 12 is filled by the pressing method (see the arrow in Fig. 4), so that the concrete 12 is filled from the lower side to the upper side. Therefore, by the concrete 12 being ejected from the first confirmation hole 44, it is possible to recognize that the concrete 12 has been filled up to the position corresponding to the lower end of the reference filling space 43, and it is possible to confirm that the concrete 12 has reached the reference filling space 43.

As shown in FIG. 3, the joint 41 in the joint space 4 is provided with a second confirmation hole 45 in addition to the first confirmation hole 44. The second confirmation hole 45 is arranged at a position corresponding to the upper end of the reference filling space 43 (a position adjacent to the bottom wall portion 23 of the upper steel pipe 21). As shown in FIG. 6, the second confirmation hole 45 is used to inject the filler 46 into the reference filling space 43 (see the arrow in FIG. 6), and to check whether the filler 46 has been injected into the gap 47 (see FIG. 5) of the reference filling space 43. As shown in FIG. 5, the concrete 12 is filled from the lower side to the upper side by the press-in method, so that a gap 47 is formed on the upper side of the reference filling space 43. Therefore, as shown in FIG. 6, the gap 47 formed on the upper side of the reference filling space 43 can be filled by injecting the filler 46 from the second confirmation hole 45 arranged at a position corresponding to the upper end of the reference filling space 43. In addition, by ejecting the filler 46 from the second confirmation hole 45, it is possible to confirm that the filler 46 has been injected into the gap 47 of the reference filling space 43.

In this way, the standard filling space 43 is secured in advance in the joint space 4, and the first confirmation hole 44 and the second confirmation hole 45 are provided in the joint 41, and then the concrete filling process is carried out. In the concrete filling process, the first pressing process (see FIG. 4) and the second pressing process (see FIG. 5) are carried out in that order to fill the lower steel pipe 11 and the joint space 4 with concrete 12, and finally, the gap filling process (see FIG. 6) is carried out to fill the gap 47 formed in the standard filling space 43 with the filler material 46.

In the first pressing step, as shown in FIG. 4, concrete 12 is pressed in by a pressing method until it reaches the reference filling space 43 (see the arrow in FIG. 4). Whether or not the concrete 12 has reached the reference filling space 43 is confirmed by whether or not the concrete 12 erupts from the first confirmation hole 44. Once it is confirmed that the concrete 12 has reached the reference filling space 43, the first confirmation hole 44 is blocked by a blocking body or the like.

In the second pressing step, as shown in FIG. 5, concrete 12 is pressed into the standard filling space 43 by the standard filling operation using the pressing method (see the arrow in FIG. 4). As a result, in the second pressing step, it is sufficient to simply perform the standard filling operation, which effectively improves workability.

In the gap filling process, as shown in FIG. 6, a filler 46 (e.g., grout) is injected into the upper side of the reference filling space 43 to fill the gap 47 (see FIG. 5) formed on the upper side of the reference filling space 43 with the filler 46 (see the arrow in FIG. 6). At this time, by injecting the filler 46 into the reference filling space 43 through the second confirmation hole 45, the filler 46 can be injected into the upper side of the reference filling space 43 where the gap 47 is formed. In addition, whether or not the filler 46 has been injected into the gap 47 of the reference filling space 43 and the gap 47 has been filled is confirmed by whether or not the filler 46 has been sprayed out from the second confirmation hole 45. When it is confirmed that the gap 47 has been filled, the second confirmation hole 45 is blocked by a blocking body or the like.

In this way, concrete 12 is filled up to the lower end of the reference filling space 43 in the first pressing process, the reference filling space 43 is filled with only the reference filling amount of concrete 12 in the second pressing process, and the gap 47 above the reference filling space 43 is filled with the filling material 46 in the gap filling process.

The above describes the construction of one CFT column assembly consisting of a lower CFT column 1 and an upper CFT column 2 that are continuous in the vertical direction, but when constructing multiple CFT column assemblies, for example, the preceding and following processes can be carried out simultaneously for multiple sets. In addition, the construction order can be set according to priorities, etc., and construction can be carried out according to the set construction order in which the preceding and following processes are carried out in sequence.

[Another embodiment]
Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied alone, but may also be applied in combination with the configurations of other embodiments.

(1) In the above embodiment, the first confirmation hole 44 is used to confirm that the reference filling space 43 has been reached in the first pressing step, but it is not limited to the first confirmation hole 44, and a separate configuration for confirming that the reference filling space 43 has been reached can also be adopted.

(2) In the above embodiment, in the gap filling process, the second confirmation hole 45 is used to inject the filler 46 into the gap 47 in the reference filling space 43 to confirm whether the gap 47 has been filled. However, it is not limited to the second confirmation hole 45, and a separate configuration can also be adopted to confirm whether the gap 47 in the reference filling space 43 has been filled.

(3) In the above embodiment, the size of the reference filling space 43 is set to the reference filling amount plus the amount of filling material 46 (e.g., grout), which is set to be larger than the reference filling amount. Alternatively, the size of the reference filling space 43 can be set to the same size as the reference filling amount. In this case, the second confirmation hole 45 can be eliminated.

1 Lower CFT column 2 Upper CFT column 3 Lower CFT column installation space 4 Joint space 11 Lower steel pipe 12 Concrete 21 Upper steel pipe 22 Concrete 41 Joint 43 Standard filling space 44 First confirmation hole 45 Second confirmation hole 46 Filling material 47 Gap

Claims (4)

In a construction method for a CFT column, a lower CFT column and an upper CFT column that are continuous in the vertical direction are constructed,
The upper steel pipe is installed in a state where the lower CFT column installation space and the joint space are secured on the lower side, and the upper steel pipe is filled with concrete to carry out the preliminary process of constructing the upper CFT column in advance.
This is a CFT column construction method in which a lower steel pipe is then installed in the lower CFT installation space, the inside of the lower steel pipe is filled with concrete to construct the lower CFT column, and a subsequent process is performed to join the lower end of the upper CFT column and the upper end of the lower CFT column in the joint space. In the subsequent process, a concrete filling process is carried out in which concrete is filled into the lower steel pipe and the joint space to construct the lower CFT column and join the lower end of the upper CFT column to the upper end of the lower CFT column,
In the concrete filling step, a standard filling space is secured in advance between the lower end of the upper steel pipe and the upper end of the lower steel pipe, which is capable of filling a standard amount of concrete based on a standard filling amount when a standard filling operation is performed, and a first pressing step is performed to press and fill the concrete until it reaches the standard filling space,
The construction method for a CFT column according to claim 1, wherein when the concrete reaches the reference filling space, a second pressing step is performed in which the concrete is pressed into the reference filling space by a reference filling operation. The construction method for a CFT column according to claim 2, which is provided with a first confirmation hole for confirming whether the concrete has reached the reference filling space, and a second confirmation hole for injecting a filler into the reference filling space and for confirming whether the filler has been injected into the gap in the reference filling space. The construction method for CFT columns according to claim 2 or 3, in which, in the subsequent process, a joint extending downward from the lower end of the upper CFT column is welded to the upper end of the lower steel pipe, and a welding joining process is performed in which the joint covers the joint space, and then the concrete filling process is performed.

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