JP2023101672A - Floor slab replacement method - Google Patents

Abstract

To provide a floor slab replacement method allowing efficient replacement of a floor slab.SOLUTION: A floor slab replacement method has an existing floor slab removing step, a new floor slab arranging preparation step, and a new floor slab arranging step. The existing floor slab removing step includes replacement of floor slab pieces of the existing floor slab. The new floor slab arranging preparation step includes a preparation work for arranging the new floor slab on a bridge girder from which the floor slab pieces are removed. The new floor slab arranging step includes arranging the new floor slab on the bridge girder where the preparation work is done. In the floor slab replacement proceeding direction, from the front side toward the rear side, a first construction region for performing the existing floor slab removing step, a second construction region for performing the new floor slab arranging preparation step, and a third construction region for performing the new floor slab arranging step, are arranged in this order. In the second construction region, from the front side toward the rear side in the proceeding direction, a construction region for performing surface preparation work to an upper face of the bridge girder and a construction region for performing installation work of a height adjusting material/seal to the upper face of the bridge girder are arranged.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for replacing a floor slab that constitutes a structure such as a bridge (removing an existing floor slab and installing a new floor slab to replace it).

A bridge, for example, includes a plurality of bridge piers, a plurality of bridge girders (H-shaped steel) each extending in the bridge axis direction across the plurality of piers, and a floor slab arranged across the plurality of bridge girders. The floor slab is made of reinforced concrete, for example. Such floor slabs may require replacement (removal of existing floor slabs and installation of new floor slabs) for reasons such as deterioration of concrete and corrosion of internal reinforcing bars due to long-term use.

As a device used for replacing floor slabs, for example, a floor slab construction machine described in Patent Document 1 is known. It is equipped with a railless, self-propelled gate-shaped structure formed by connecting front and rear gate-shaped frames in the bridge axis direction, and a lifting device (for example, a chain block) provided on the lower surface of the ceiling of the gate-shaped structure so as to be movable in the longitudinal and lateral directions. Here, the new floor slabs are made of precast concrete.

Erection work of new floor slabs using such erection machines
(1) Taking in the new floor slab at the rear of the erection machine, that is, lifting the new floor slab by the lifting device located at the rear of the erection machine with the long side of the new slab facing the direction of the bridge axis (2) Transferring the new slab to the installation position by moving the lifting device forward (3) Changing the direction of the new slab so that the long side of the new slab faces the direction perpendicular to the bridge axis (rotate 90°)
(4) Then, it is carried out in a step of installation at a predetermined position.
In addition, the removal work of the existing floor slabs is carried out almost in the reverse order.

Japanese Patent No. 3901657

However, in the above-mentioned floor slab replacement method using an erection machine, after removing the existing floor slab and installing a new floor slab at a certain construction site, the above-mentioned erection machine moves in the direction of the bridge axis and removes the existing floor slab and installs a new floor slab at the next construction site. Therefore, until the floor slab replacement work at a certain construction site is completed, the floor slab replacement work cannot be started at the next construction site.

SUMMARY OF THE INVENTION In view of such circumstances, it is an object of the present invention to provide a floor slab replacement method that enables efficient replacement of floor slabs in a structure such as a bridge.

Therefore, the first aspect and the second aspect of the floor slab replacement method according to the present invention are methods for replacing an existing floor slab on a bridge girder with a new floor slab in a structure having a bridge girder. A first aspect and a second aspect of the floor slab replacement method according to the present invention have an existing floor slab removal step, a new floor slab placement preparation step, and a new floor slab placement step, wherein the existing floor slab removal step includes removing floor slab pieces of the existing floor slab, the new floor slab placement preparation step includes preparatory work for placing the new floor slab on the bridge girders from which the floor slab pieces have been removed, and the new floor slab placement step includes the bridge girders on which the preparation work has been performed. including placement of new floor slabs on In the first aspect of the floor slab replacement method according to the present invention, the preparatory work includes shaving work on the upper surface of the bridge girder and installation work of height adjustment members on the upper surface of the bridge girder. In the second aspect of the floor slab replacement method according to the present invention, the preparatory work includes cleaning work on the upper surface of the bridge girder and installation work of seals on the upper surface of the bridge girder. In the first aspect and the second aspect of the floor slab replacement method according to the present invention, a plurality of construction areas are set in the axial direction of the structure. In the first aspect and the second aspect of the floor slab replacement method according to the present invention, the first construction area in which the existing floor slab removal process is performed, the second construction area in which the new floor slab layout preparation process is performed, and the third construction area in which the new floor slab layout process is performed are arranged in order from the front side to the rear side of the movement direction in the floor slab replacement construction progress direction along the axial direction. In the first aspect of the floor slab replacement method according to the present invention, in the second construction area, in order from the front side to the rear side in the traveling direction, a cleaning work execution area for performing cleaning work and a height adjustment material installation work execution area for performing the height adjustment material installation work are arranged. In the second aspect of the floor slab replacement method according to the present invention, in the second construction area, in order from the front side to the rear side in the traveling direction, the cleaning work execution area for performing the cleaning work and the seal installation work The seal installation work construction area for performing the work is lined up. In the first aspect and the second aspect of the floor slab replacement method according to the present invention, the first crane device used in the existing floor slab removal process is positioned on the existing floor slab on the bridge girder, and the second crane device used in the new floor slab placement process is positioned on the floor slab newly installed on the bridge girder. In the first and second aspects of the floor slab replacement method according to the present invention, the first construction area, the second construction area, and the third construction area advance in the direction of movement as the floor slab replacement construction progresses. In the first aspect and the second aspect of the floor slab replacement method according to the present invention, a floor slab piece is transported forward in the traveling direction from the first crane device by a transport vehicle traveling on an existing floor slab on a bridge girder, and a new floor slab is carried into the second crane device from behind in the traveling direction by a carriage traveling on the floor slab newly installed on the bridge girder.

According to the present invention, construction can be carried out in parallel (that is, at the same time) in a plurality of construction areas where the progress of floor slab replacement construction is different, so that floor slab replacement can be performed efficiently (in other words, in a short period of time).

Side view of an example of an existing bridge FIG. 2 is a side view showing a construction state of the floor slab replacement method according to the first embodiment of the present invention. Flowchart showing the main routine of the floor slab replacement method in the first embodiment Flowchart showing a subroutine of the floor slab replacement method in the first embodiment Flowchart showing the method for removing the existing floor slab in the first embodiment Flowchart showing a method of preparing for placement of new floor slabs in the first embodiment Flowchart showing a method for arranging new floor slabs in the first embodiment A diagram showing a method for cutting an existing floor slab in the first embodiment. A diagram showing a method for cutting an existing floor slab in the first embodiment. A diagram showing the edge cutting method of the existing floor slab in the first embodiment. A diagram showing the edge cutting method of the existing floor slab in the first embodiment. A diagram showing a method of preparing for placement of a new floor slab in the first embodiment. A diagram showing a method of preparing for placement of a new floor slab in the first embodiment. A diagram showing a method of preparing for placement of a new floor slab in the first embodiment. A diagram showing a method of arranging a new floor slab in the first embodiment. A diagram showing a method of arranging a new floor slab in the first embodiment. The figure which shows the installation method of the stud dowel in the said 1st Embodiment. A diagram showing the relationship between the time and the work process of each construction area in the first embodiment. A diagram showing the relationship between the time and the work process of each construction area in the first embodiment. A diagram showing the relationship between the time and the work process of each construction area in an example of the conventional floor slab replacement method A diagram showing the relationship between the time and the work process of each construction area in the second embodiment of the present invention. A diagram showing the relationship between the time and the work process of each construction area in the second embodiment. Flowchart showing a method for arranging a new floor slab in the third embodiment of the present invention Flowchart showing a new floor slab placement preparation method according to the fourth embodiment of the present invention Flowchart showing a method for arranging new floor slabs according to the fifth embodiment of the present invention Flowchart showing a method of preparing for placement of new floor slabs according to the sixth embodiment of the present invention

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same or corresponding parts.

FIG. 1 is a side view of an example of an existing bridge to which the floor slab replacement method according to the present invention can be applied. FIG. 2 is a side view showing a construction state of the floor slab replacement method according to the first embodiment of the present invention. In the present embodiment, the forward and backward directions are defined as shown in FIGS. 1 and 2, with the progress direction of the floor slab replacement work on the bridge being the forward direction. Here, the progress direction of the floor slab replacement construction is along the axis direction of the bridge. Further, in this embodiment, the direction perpendicular to the axis of the bridge is defined as the lateral direction (horizontal direction) in the following description (see FIGS. 10A to 12).

In this embodiment, a bridge will be described as an example of the "structure" (civil engineering structure) of the present invention, but the "structure" of the present invention is not limited to a bridge. Also, the above-mentioned bridge axial direction can correspond to the "axial direction of the structure" and the "axial direction of the bridge" of the present invention.

A bridge 1, which is an example of the "structure" of the present invention, includes a pair of front and rear abutments 2a, 2b, a plurality of piers 3 spaced apart between the abutments 2a, 2b, a plurality of bridge girders (H-shaped steel) 4 each straddling over the abutments 2a, 2b and the plurality of piers 3 and extending in the bridge axis direction, and an existing concrete deck 5 straddling over the plurality of bridge girders 4. Supports (not shown) are interposed between the bridge abutments 2a and 2b and the plurality of bridge piers 3 and the plurality of bridge girders 4. As shown in FIG. In this embodiment, the existing floor slab 5 is made of reinforced concrete (RC floor slab), but the existing floor slab 5 may be made of prestressed concrete (PC floor slab). Moreover, the bridge girder 4 has a web 4w, an upper flange 4f, and a lower flange (not shown), as shown in FIGS. 10A to 10C, which will be described later.

In the present embodiment, the description will be made assuming that the total length (bridge length) Lt of the bridge 1 is 300 m, but the total length Lt of the bridge 1 is not limited to 300 m. In this embodiment, the existing floor slab 5 is not divided in the direction perpendicular to the bridge axis of the bridge 1, so-called full-section floor slab replacement construction will be described below, but the construction form is not limited to this.

3 and 4 in addition to FIGS. 1 and 2, the floor slab replacement method in this embodiment will be described. FIG. 3 is a flow chart showing the main routine of the floor slab replacement method in this embodiment. FIG. 4 is a flow chart showing a subroutine of the floor slab replacement method in this embodiment.

The floor slab replacement construction of the bridge 1 (removal of the existing floor slab 5 and installation of the new floor slab 7 in its place) generally follows the main routine shown in FIG.

First, in step S101, a plurality of construction areas A ₁ to A _n are set by dividing the bridge 1 into a plurality of (n in this embodiment) construction areas A ₁ to A _n in the bridge axis direction. In this embodiment, the length of each of the construction areas A ₁ to A _n in the bridge axis direction is assumed to be 6 m, but the length of each of the construction areas A ₁ to A _n in the bridge axis direction is not limited to 6 m. For example, if the total length Lt of the bridge 1 is 300 m and the length in the bridge axis direction of each of the construction areas A ₁ to A _n is 6 m, then n=300/6=50.

Next, in step S102, the existing floor slabs 5 are removed and the new floor slabs 7 are arranged to replace them in each of the construction areas A ₁ to A _n . In this embodiment, for example, as shown in FIG. 2, floor slab replacement work can be performed in parallel in a plurality of construction areas A _k to A _k-6 . In the present embodiment, different work processes can be performed in parallel in a construction area on the front side (for example, construction area A _k-4 ) and a construction area behind this construction area (for example, construction area A _k-6 ) in the progress direction of floor slab replacement construction.

When the existing floor slabs 5 are removed and the new floor slabs 7 are placed to replace them in all of the construction areas A ₁ to A _n (that is, when the placement of the new floor slabs 7 is completed over the entire length Lt of the bridge 1), the process proceeds to step S103, where the new floor slabs 7 and the bridge girders 4 are fixed and integrated, and the new floor slabs 7 adjacent in the bridge axis direction are fixed and integrated.
Thus, the floor slab replacement construction of the bridge 1 is performed.

Regarding step S102 described above, each of the construction areas A ₁ to A _n has a plurality of work steps from removing the existing floor slab 5 to arranging the new floor slab 7 . This multi-stage work process is shown in FIG.
As shown in FIG. 4, first, in step S1, as the first stage (first stage), the existing floor slab 5 is removed. Here, step S1 corresponds to the "first work process" of the present invention.

Next, in step S2, as the middle stage (second stage), preparation work for arranging the new floor slab 7 in the construction area from which the existing floor slab 5 has been removed (preparation work for arranging the new floor slab 7) is performed. Here, step S2 corresponds to the "second work process" of the present invention.

Next, in step S3, as the latter stage (third stage), the new floor slab 7 is placed in the construction area where the preparation work for the placement of the new floor slab 7 has been performed. Here, step S3 corresponds to the "third work process" of the present invention.

Here, the work of removing the existing floor slab 5 performed in step S1 will be described using FIGS.
FIG. 5 is a flow chart showing a method for removing the existing floor slab 5 in this embodiment. 8A and 8B are diagrams showing a method of cutting the existing floor slab 5 in this embodiment. 9A and 9B are diagrams showing the edge cutting method of the existing floor slab 5 in this embodiment.

As shown in FIG. 5, first, in step S11, the existing floor slab 5 is cut. In this step S11, as shown in FIGS. 8A and 8B, a cutting line 5b is set at a predetermined length La ahead of the rear end of the existing floor slab 5, and along this cutting line 5b, the existing floor slab 5 is cut using a concrete cutting device such as a concrete cutter or a wire saw to form a floor slab piece 5a. Although the predetermined length La is 2 m in this embodiment, the predetermined length La is not limited to 2 m.

Next, in step S12, the floor slab piece 5a of the existing floor slab 5 is trimmed. In this step S12, first, as shown in FIG. 9A, a plurality of jacks 50a and 50b in a shortened state are installed on the front and rear sides of the floor slab piece 5a, respectively. Here, the jacks 50a and 50b are vertically extendable, and are hydraulic jacks, for example.

The lower end of the front jack 50 a abuts on the upper surface of the existing floor slab 5 . The lower end of the rear jack 50b contacts the upper surface 4a of the bridge girder 4 (specifically, the upper surface 4a of the upper flange 4f of the bridge girder 4 shown in FIGS. 10A to 10C).

Moreover, as shown in FIG. 9A, a beam member 51 is arranged so as to straddle over the jacks 50a and 50b. The beam member 51 is fixed to the upper ends of the jacks 50a and 50b. The beam member 51 has a bracket (not shown), and a vertically extending PC steel rod 52 is arranged so as to pass through the bracket and the floor slab piece 5a. The PC steel rods 52 are arranged so as to avoid the bridge girder 4 . Fixing members 53a and 53b for fixing the PC steel bar 52 to the beam member 51 (the aforementioned bracket) and the floor slab piece 5a are attached to the upper end and the lower end of the PC steel bar 52, respectively.

Next, as shown in FIG. 9B, the floor slab piece 5a is pulled up via the beam member 51 (the aforementioned bracket) and the PC steel rod 52 by operating the jacks 50a and 50b to extend. After the floor slab piece 5a is separated (edge cut) from the bridge girder 4 in this manner, the jacks 50a and 50b are shortened, and the PC steel rod 52, the beam member 51, and the jacks 50a and 50b are removed.

Next, in step S13 of FIG. 5, the floor slab piece 5a cut off from the bridge girder 4 is lifted by the crane device 20 shown in FIG. This transport vehicle can carry out the floor slab piece 5a from the construction areas A ₁ to A _n forward in the direction in which the floor slab replacement construction progresses. In addition, this transport vehicle can run on the existing floor slab 5 .

The crane device 20 includes a pair of left and right lower frames 21 extending in the front-rear direction, a portal frame 22 whose lower ends are connected to the pair of left and right lower frames 21, an upper frame 23 provided on the upper part of the portal frame 22, and a lifting device 24 movable in the front, rear, left, and right directions with respect to the upper frame 23. A pair of left and right lower frames 21 are provided with wheels capable of rolling on the existing floor slab 5 . Inside the gate-shaped frame 22 and between the pair of left and right lower frames 21, the above-described loading platform of the transport vehicle can be arranged.

In this embodiment, the steps S11 to S13 described above are performed three times for each construction area (that is, for each construction area A ₁ to A _n ), thereby removing 6 m of the existing floor slab 5, which is the length of one construction area in the bridge axis direction.
As described above, the work of removing the existing floor slab 5 is carried out in step S1 of FIG.

6 and 10A to 10C in addition to FIGS.
FIG. 6 is a flow chart showing a method of preparing for placement of the new floor slab 7 in this embodiment. 10A to 10C are diagrams showing a method of preparing for placement of the new floor slab 7 in this embodiment. Here, FIGS. 10A to 10C correspond to the II section of FIG. 11A, which will be described later.

As shown in FIG. 6, first, in step S21, the existing floor slab 5 (floor slab piece 5a) is removed and the upper surface 4a of the bridge girder 4 exposed to the outside (specifically, the upper surface 4a of the upper flange 4f of the bridge girder 4 shown in FIG. 10A) is cleaned. Here, the cleaning work may include removing concrete pieces or the like remaining on the upper surface 4 a of the bridge girder 4 .

Next, in step S22, flange seals 60 made of, for example, rubber are installed on both left and right sides of the upper flange 4f of the bridge girder 4 on which the cleaning work has been performed (see FIG. 10B). The flange seal 60 has a plate shape extending in the bridge axis direction. This flange seal 60 is to prevent the mortar cast in the space 9 (see FIG. 11B) between the new floor slab 7 and the bridge girder 4 from leaking out of the space 9 when the new floor slab 7 and the bridge girder 4 are fixed and integrated in step S103.

Next, in step S23, a plurality of height adjusting members 70 for adjusting the placement height of the new floor slab 7 are installed on the upper surface 4a of the upper flange 4f of the bridge girder 4 (see FIG. 10C). It is preferable that the height adjusting member 70 is vertically extendable. The height adjustment member 70 may be, for example, a vertically extendable manual jack. Alternatively, the height adjustment member 70 may be configured by a rigid member (spacer) that cannot be deformed after its own height is determined. The plurality of height adjusting members 70 are arranged in the longitudinal direction of the bridge at intervals.

Regarding the height adjusting material 70, the height of the height adjusting material 70 itself can be adjusted prior to placing the new floor slab 7 on the bridge girder 4 so that when the new floor slab 7 is placed on the bridge girder 4 in step S3 described above and step S31 described later, the height of the new floor slab 7 will be the planned placement height. The height adjustment of the height adjusting member 70 itself may be performed before installation on the upper surface 4a of the upper flange 4f of the bridge girder 4 in step S23, or may be performed after installation on the upper surface 4a of the upper flange 4f of the bridge girder 4.

In this embodiment, the height adjusting member 70 is installed after the flange seal 60 is installed, but the height adjusting member 70 may be installed before the flange seal 60 is installed. That is, step S22 and step S23 may be interchanged.
As described above, in step S2 of FIG. 4, the new floor slab 7 is prepared for placement.

7, 11A, 11B and 12 in addition to FIGS.
FIG. 7 is a flow chart showing a method of arranging the new floor slabs 7 in this embodiment. 11A and 11B are diagrams showing a method of arranging the new floor slab 7 in this embodiment. Here, FIG. 11B corresponds to the II section of FIG. 11A. 12A and 12B are diagrams showing a method of installing the stud dowel 80. FIG.

As shown in FIG. 7, first, in step S31, the new floor slab 7 is placed on a plurality of height adjusting members 70 installed on the upper surface 4a of the upper flange 4f of the bridge girder 4 (see FIGS. 11A and 11B). As a result, a space 9 surrounded by the upper surface 4a of the upper flange 4f of the bridge girder 4, the lower surface 7b of the new floor slab 7, and the flange seal 60 is formed.

The new floor slab 7 is made of precast concrete (that is, it is a PCa floor slab). The new floor slab 7 has a substantially rectangular shape with short sides extending in the direction of the bridge axis and long sides extending in the direction perpendicular to the axis. In this embodiment, the length of the new floor slab 7 in the bridge axis direction is 2 m, but the length of the new floor slab 7 in the bridge axis direction is not limited to 2 m.
A plurality of through holes 7a are formed in the new floor slab 7 so as to face the upper surface 4a of the upper flange 4f of the bridge girder 4. As shown in FIG.

The crane device 30 shown in FIG. 2 is used for the placement work (placing work) of the new floor slab 7 in step S31. The crane device 30 includes a pair of left and right lower frames 31 extending in the front-rear direction, a portal frame 32 whose lower ends are connected to the pair of left and right lower frames 31, an upper frame 33 provided on the upper part of the portal frame 32, and a lifting device 34 movable in the front, rear, left, and right directions with respect to the upper frame 33. A pair of left and right lower frames 31 are provided with wheels capable of rolling on the new floor slab 7 placed on the bridge girder 4 . A carriage 40 can travel inside the portal frame 32 and between the pair of left and right lower frames 31 .

The new floor slab 7 scheduled to be lifted by the crane device 30 is transported from the ground adjacent to the abutment 2b (see FIG. 1) to the crane device 30 by the carriage 40 . The traveling stability of the carriage 40 may be improved by laying a plate-like member such as an iron plate so as to cover the gap between the adjacent new floor slabs 7 placed on the bridge girder 4 from above. The carriage 40 may be self-propelled. The carriage 40 preferably includes wheels with rubber tires.

On the ground adjacent to the abutment 2b, the new floor slab 7 scheduled to be transported by the carriage 40 to the crane device 30 is unloaded from a transport vehicle (not shown) to the carriage 40 lighter in weight than the transport vehicle. For this unloading work, a crane device having the same configuration as the crane devices 20 and 30 described above may be used.
Therefore, in the present embodiment, the new floor slab 7 is carried into the construction areas A ₁ to A _n from behind in the direction in which the floor slab replacement construction progresses.

In the present embodiment, after the new floor slab 7 is lifted from the carriage 40 by the crane device 30, the orientation of the new floor slab 7 is changed by the crane device 30 so that the long side of the new floor slab 7 is directed in the direction perpendicular to the bridge axis (i.e., rotated by 90°).

In the present embodiment, the above-mentioned step S31 is performed three times for each construction area (that is, for each of the construction areas A ₁ to A _n ), thereby arranging the new floor slabs 7 for 6 m (that is, three pieces), which is the length of one construction area in the bridge axis direction.

Next, in step S32 of FIG. 7, a plurality of stud dowels 80 are welded and fixed to the upper surface 4a of the upper flange 4f of the bridge girder 4 so as to be positioned within the through holes 7a of the new floor slab 7, as shown in FIG. If the carriage 40 passes during the installation work of the stud dowel 80 in step S32, the installation work of the stud dowel 80 is interrupted when the carriage 40 passes.
As described above, the work of arranging the new floor slab 7 is carried out in step S3 of FIG.

In the construction state at a certain time shown in FIG. 2, the crane device 20 is positioned in the construction area _Ak+1 . In the construction area A _k located behind the construction area A _k+1 , the work shown in the above step S1 (steps S11 to S13) is being performed. In the construction area A _{k-1 located behind the construction area A k ,} the work shown in step S21 is being performed. In the construction area A _{k- 2 located behind the construction area A k-1} , the work shown in step S22 is being performed. In the construction area A k _{-3 located behind the construction area A k- 2} , the work shown in step S23 is being performed. In the construction area A _k-4 located behind the construction area A _k-3 , the work shown in step S31 is being performed. A crane device 30 is positioned in the construction area A _k-5 located behind the construction area A _k-4 . In the construction area A k _-6 located behind the construction area A _k-5 , the work shown in step S32 is being performed. The symbol “α” shown in FIG. 2 indicates that the work is suspended during the steps S1 to S3 (steps S11 to S32) described above.

In the present embodiment, a temporary tent 10 is provided so as to cover the construction area where the work of step S1 is performed (for example, the construction area A _k shown in FIG. 2) to the construction area where the work of step S32 is performed (for example, the construction area A _k-6 shown in FIG.). Therefore, the cleaning work in step S<b>21 and the welding work in step S<b>32 are performed inside the temporary tent 10 . The construction area covered by the temporary tent 10 is not limited to that shown in FIG.

In this way, in the present embodiment, different work processes can be carried out in parallel (i.e., simultaneously) in the construction area on the front side and the construction area behind this construction area in the direction in which the floor slab replacement construction progresses.
Further, in the present embodiment, in the floor slab replacement construction progress direction, the more from the construction area on the front side to the construction area on the rear side (for example, the more from the construction area A _k shown in FIG. 2 toward the construction area A _k−6 ), the more the work process (steps S1 to S32) in a later stage (that is, closer to step S32).

In this embodiment, as shown in FIG. 2, the crane device 20 is positioned in front of the crane device 30 in the direction in which the floor slab replacement construction progresses.

In this embodiment, the temporary tent 10 and the crane devices 20 and 30 move forward as the floor slab replacement construction progresses. Therefore, a floor slab replacement system capable of executing a plurality of work processes (steps S1 to S32) in parallel (that is, at the same time) also advances. Here, this floor slab replacement system includes a temporary tent 10 and crane devices 20 and 30 .

FIG. 13 is a diagram showing the relationship between the time t=t1 to t10 and the work process of each of the construction areas A ₁ to A ₉ in this embodiment. FIG. 14 is a diagram showing the relationship between the times t=t1 to t15 and the work processes of the construction areas A ₁ to A ₈ in this embodiment.

13 and 14, similarly to FIG. 2, indicates that the work is suspended in the middle of steps S1 to S3 (steps S11 to S32).

Also, the time between times t1 and t2, the time between times t2 and t3, . In addition, the work process times of steps S1, S21, S22, S23, S31, and S32 are the same for one construction area (that is, each of the construction areas A ₁ to A _n ). When setting the work process time, it is possible to consider which work process is the critical path among steps S1, S21, S22, S23, S31, and S32.

As shown in FIGS. 13 and 14, in this embodiment, between times t1 and t13, floor slab replacement (removal of the existing floor slab 5 and placement of the new floor slab 7 to replace it) in the construction areas A ₁ to A ₆ is completed.

In this regard, FIG. 15 shows the relationship between the times t1 to t13 and the respective work steps in the construction areas A ₁ and A ₂ in an example of the conventional floor slab replacement method. FIG. 15 shows that after removing the existing floor slab 5 and placing the new floor slab 7 in place of it in the construction area _A1 , the removal _of the existing floor slab 5 and placement of the new floor slab 7 in place of it in the construction area A2 takes a working time of t1 to t13.

Therefore, as is clear from the illustrations in FIGS. 13 to 15, the floor slab replacement method of the present embodiment can be used to proceed with floor slab replacement construction much more quickly than the conventional floor slab replacement method.

In step S103 of FIG. 3 described above, mortar is injected and cast into the space 9 (see FIG. 11B) from the through holes 7a of the new floor slab 7 placed on the bridge girder 4, and the new floor slab 7 and the bridge girder 4 are fixed and integrated by this mortar and the stud dowels 80 (see FIG. 12). Further, in step S103 of FIG. 3 described above, reinforced concrete work is carried out in the gaps (not shown) between the new floor slabs 7 that are adjacent in the bridge axis direction, so that these new floor slabs 7 are fixed and integrated.

According to this embodiment, the floor slab replacement method includes setting a plurality of construction areas A ₁ to A _n by dividing the structure (bridge 1) into a plurality of construction areas A ₁ to A _n in the axial direction of the structure (bridge 1). Each of the construction areas A ₁ to A _n has a plurality of work processes (steps S1 to S3 (S11 to S32)) from removal of the existing floor slab 5 to placement of the new floor slab 7 . In the floor slab replacement construction progress direction along the axial direction (bridge axis direction) of the structure (bridge 1), different work processes are performed in parallel in the construction area on the front side of the floor slab replacement construction progress direction and the construction area behind the floor slab replacement construction progress direction from this construction area (see FIGS. 2, 13 and 14). As a result, construction can be carried out in parallel (that is, at the same time) in a plurality of construction areas where the progress of floor slab replacement construction is different, so that the replacement from the existing floor slab 5 to the new floor slab 7 can be efficiently performed (in other words, in a short period of time) (see FIGS. 13 to 15).

In addition, according to the present embodiment, a plurality of work steps are performed in parallel so that the work process becomes later as it goes from the construction area on the front side of the floor slab replacement construction progress direction to the construction area on the rear side of the floor slab replacement construction _progress direction ₍ for example, as shown in FIG. As a result, each work process can be continued and advanced along the progress direction of the floor slab replacement construction, so that the occurrence of downtime (work waiting time) in each work process can be suppressed, and the floor slab replacement construction can be efficiently performed.

Further, according to this embodiment, the removed existing floor slab 5 (floor slab piece 5a) is carried forward from the construction areas A ₁ to _An in the floor slab replacement construction progress direction, and the new floor slab 7 is carried into the construction areas A ₁ to _An from the rear in the floor slab replacement construction progress direction. As a result, it is possible to prevent the work of carrying out the existing floor slab 5 (floor slab piece 5a) and the work of carrying in the new floor slab 7 from being complicated.

According to the present embodiment, the work process of multiple steps in which each construction area A ₁ to _A has, each of which has the first work process (step S1), which implements the removal of the existing floor version 5 in the construction area, and the preparation work to place a new floor version 7 in the construction area where the existing floor version 5 has been removed. Includes the second work process (step S2) to be applied and the third work process (step S3), which allows the new floor version 7 to be placed in the construction area where the preparation work was implemented. Therefore, by making various preparations for the placement of the new floor slabs 7 prior to placement of the new floor slabs 7, the placement of the new floor slabs 7 can be performed smoothly.

Further, according to the present embodiment, the second work process (step S2) includes providing the height adjustment material 70 on the upper surface 4a of the bridge girder 4 of the bridge 1 for adjusting the placement height of the new floor slab 7 to be placed in the construction area in the third work process (step S3) (step S23). As a result, in step S31 (step S3), the new floor slab 7 can be easily placed in the construction area at the planned placement height.

Further, according to the present embodiment, the second work process (step S2) includes performing the scraping work on the upper surface 4a of the bridge girder 4 of the bridge 1 (step S21). This cleaning work is carried out inside the temporary tent 10 . Therefore, since the temporary tent 10 can function as a rain cover, cleaning work can be carried out even in rainy weather. In addition, since the dust generated by the cleaning work can remain in the temporary tent 10, it is possible to suppress the scattering of the dust to the outside.

Further, according to the present embodiment, the welding work is carried out inside the temporary tent 10 in the work process including the welding work (for example, step S32) among the multiple stages of work processes of each of the construction areas A ₁ to A _n . Therefore, since the temporary tent 10 can function as a rain cover, welding work can be carried out even in rainy weather.

Further, according to this embodiment, the new floor slab 7 is made of precast concrete. Therefore, it is possible to simplify the installation work of the new floor slab 7 at the floor slab replacement construction site.

Further, according to the present embodiment, after the placement of the new floor slab 7 over the entire length of the bridge 1 is completed, the new floor slab 7 and the bridge girder 4 of the bridge 1 are fixed and integrated, and the new floor slabs 7 adjacent in the axial direction of the bridge 1 (bridge axis direction) are fixed and integrated (step S103). Thus, the integration of the new floor slab 7 and the bridge girder 4 and the integration of the adjacent new floor slabs 7 can be collectively performed over the entire length of the bridge 1, so that these integration work can be efficiently performed in a short period of time.

In this embodiment, after the new floor slab 7 and the bridge girder 4 have been laid out over the entire length of the bridge 1, the new floor slab 7 and the bridge girder 4 are fixed and integrated, and the new floor slabs 7 adjacent to each other in the bridge axis direction are fixed and integrated. Adjacent new floor slabs 7 may be fixed and integrated.

FIGS. 16A and 16B are diagrams showing the relationship between times t1 to t19 and work steps in the construction areas A ₁ to A ₂₀ in the second embodiment of the present invention.
Differences from the first embodiment described above will be described.

In this embodiment, the length in the bridge axis direction of each of the construction areas A ₁ to A _n is shortened compared to the first embodiment. In this embodiment, the length of each of the construction areas A ₁ to A _n in the bridge axis direction is set to 2 m, but the length of each of the construction areas A ₁ to A _n in the bridge axis direction is not limited to 2 m. For example, if the total length Lt of the bridge 1 is 300 m and the length in the bridge axis direction of each of the construction areas A ₁ to A _n is 2 m, then n=300/2=150.

Further, in the present embodiment, the time between times t1 and t2, the time between times t2 and t3, .

According to the present embodiment, the work process time of step S1 is 0.4 hours for one construction area (that is, each of the construction areas A ₁ to A _n ), the work process time of step S21 is 0.8 hours (0.4 hours x 2), and the step S22 and S23 work time is 1.4 (0.4 (0.4). Time x 3), step S31 work processing time is 0.4 hours, and the work process time for step S32 is 0.4 hours.

In this embodiment, as shown in FIGS. 16A and 16B, it is possible to optimize the time allocation for each work process and optimize the work range of each work process according to the characteristics of each work process. For example, at times t6 to t7, t9 to t10 in FIG. 16A and times t12 to t13, t15 to t16, t18 to t19 in FIG. 16B, by pausing the cleaning work in step S21, the chronic generation of dust in the temporary tent 10 can be suppressed.

FIG. 17 is a flow chart showing a method of arranging the new floor slabs 7 according to the third embodiment of the present invention.
Differences from the first embodiment described above will be described.

In this embodiment, step S33 is added after step S32 instead of step S103. That is, in the present embodiment, the stud dowel 80 is installed in step S32 for each construction area (that is, in each construction area A ₁ to A _n ), and subsequently, in step S33, the new floor slab 7 and the bridge girder 4 are fixed and integrated, and the new floor slabs 7 adjacent in the bridge axis direction are fixed and integrated. These integration operations are the same as those in the first embodiment described above, so description thereof will be omitted.

It goes without saying that in the above-described second embodiment, step S33 may be added after step S32 instead of step S103, as in the present embodiment.

FIG. 18 is a flow chart showing a method of preparing for placement of the new floor slab 7 according to the fourth embodiment of the present invention.
Differences from the first embodiment described above will be described.

In this embodiment, after the top surface 4a of the upper flange 4f of the bridge girder 4 is cleaned in step S21, the process proceeds to step S24 to measure the shape of the top surface 4a of the upper flange 4f of the bridge girder 4. After this survey is completed, the process proceeds to step S22, and flange seals 60 are installed on both left and right sides of the upper flange 4f of the bridge girder 4. As shown in FIG. That is, in this embodiment, step S24 is added between step S21 and step S22.

It goes without saying that in the above-described second and third embodiments, step S24 may be added between steps S21 and S22 as in the present embodiment.

FIG. 19 is a flow chart showing a method of arranging the new floor slabs 7 according to the fifth embodiment of the present invention.
Differences from the first embodiment described above will be described.

In this embodiment, after placing the new floor slab 7 on the plurality of height adjustment members 70 installed on the upper surface 4a of the upper flange 4f of the bridge girder 4 in the above-described step S31, the process proceeds to step S34 to adjust the height of the new floor slab 7. After this height adjustment is completed, the process proceeds to step S32, and a plurality of stud dowels 80 are welded and fixed to the upper surface 4a of the upper flange 4f of the bridge girder 4 so as to be positioned within the through holes 7a of the new floor slab 7. That is, in this embodiment, step S34 is added between step S31 and step S32.

It goes without saying that in the above-described second to fourth embodiments, step S34 may be added between steps S31 and S32 as in the present embodiment.

FIG. 20 is a flow chart showing a method of preparing for placement of the new floor slab 7 according to the sixth embodiment of the present invention.
Differences from the first embodiment described above will be described.

In this embodiment, a plurality of inserts are embedded in the new floor slab 7 . Each insert has a female screw portion that vertically penetrates the new floor slab 7 . A male threaded portion of a bolt having a head on the upper side is screwed into the female threaded portion. The lower end of the male threaded portion of the bolt protrudes downward from the lower surface 7b of the new floor slab 7 and can abut on the upper surface 4a of the upper flange 4f of the bridge girder 4. As shown in FIG. By changing the screwing degree of the male threaded portion of the bolt with respect to the female threaded portion, the amount by which the lower end portion of the male threaded portion of the bolt protrudes downward from the lower surface 7b of the new floor slab 7 can be changed. Therefore, these inserts and bolts (hereinafter referred to as “insert bolts”) can function as height adjusting members for adjusting the height of the new floor slab 7 .

In this embodiment, a plurality of height adjusting members (for example, insert bolts described above) for adjusting the placement height of the new floor slab 7 are provided on the new floor slab 7 prior to step S31 described above. Therefore, since the height adjusting member 70 described above is not required, in this embodiment, as shown in FIG. 20, step S23 described above can be omitted.

In the above-described second to fifth embodiments, if a plurality of height-adjusting members (for example, the above-described insert bolts) for adjusting the arrangement height of the new floor slab 7 are provided on the new floor slab 7 prior to step S31, step S23 can be omitted because the height-adjusting members 70 are not required. In particular, in the above-described fifth embodiment, if a plurality of height adjusting members (for example, the above-described insert bolts) for adjusting the arrangement height of the new floor slab 7 are provided on the new floor slab 7 prior to step S31, and step S23 is omitted, these height-adjusting members (for example, the above-described insert bolts) can be used in adjusting the height of the new floor slab 7 in step S34.

In the above-described first embodiment, work teams including workers and equipment are individually organized (that is, division of labor) so as to correspond to each of a plurality of work processes (steps S1, S21 to S23, S31, and S32), and these work teams are arranged in a line in the bridge axis direction according to the order of the work processes (steps S1, S21 to S23, S31, and S32) (that is, a production line for floor slab replacement consisting of these work teams). things are formed). Then, these work teams repeat the execution of each work and the forward movement in parallel, and the floor slab replacement construction progresses. Therefore, the floor slab replacement construction progresses through assembly line work involving forward movement by these work teams. This point applies not only to the first embodiment, but also to the second to sixth embodiments. Here, by utilizing ICT (information and communication technology) including AI (artificial intelligence) technology for the work by each work team and the cooperation between work teams, part or all of the floor slab replacement construction can be automated, and as a result, productivity can be greatly improved. Therefore, the floor slab replacement method according to the present invention can improve productivity in infrastructure maintenance and management renewal by promoting i-Construction (registered trademark) by utilizing ICT, etc., and can be one of the basic technologies for contributing to an increase in the number of young people entering the construction industry by creating an attractive work environment, and has great industrial applicability.

In the above-described first to sixth embodiments, for example, when the work is likely to be delayed in any of the construction areas A ₁ to A _n , the organization (configuration) of the work team may be changed according to the progress of the construction, such as by increasing the number of workers in the construction area where the work is likely to be delayed (that is, the organization (configuration) of the work team may be flexible).

In the above-described first to sixth embodiments, an example was shown in which the floor slab replacement construction progresses while the length in the bridge axis direction of the construction area where the work for removing the existing floor slab 5 (step S1 described above) is performed is constant (6 m in the first and third to sixth embodiments, and 2 m in the second embodiment). In addition, the length in the bridge axis direction of the construction area where the work for removing the existing floor slab 5 (step S1 described above) is performed may change depending on the time. That is, flexibility may be given to the length in the bridge axis direction of the construction area where the work of removing the existing floor slab 5 (step S1 described above) is performed. If the length in the bridge axis direction of the construction area where the removal work of the existing floor slab 5 (step S1 described above) is performed changes according to time, subsequent work can be appropriately adjusted so as to follow it.

In the first to sixth embodiments described above, the construction areas A ₁ to A _n have a constant length in the bridge axis direction (6 m in the first and third to sixth embodiments, and 2 m in the second embodiment). In addition, the construction areas A ₁ to A _n may have different lengths in the bridge axis direction.

In the above-described first embodiment, in each of the construction areas A ₁ to A _n , a work suspension period (a period corresponding to the symbol “α” in FIG. 2) is provided between the above-described steps S31 and S32. However, this work suspension period is not limited to between the above-described steps S31 and S32. In addition to or instead of this, at least one of between steps S1 and S21, between steps S21 and S22, between steps S22 and S23, and between steps S23 and S31 may optionally be provided with an operation pause period. This point applies not only to the first embodiment but also to the second to sixth embodiments. Here, the work suspension period can function as an adjustment allowance for the work time of each work.

In the first to sixth embodiments described above, the order of the work processes in the construction areas A ₁ to A _n is the same, but the order of some of the work processes in the construction areas A ₁ to A _n may differ from the order of the work processes described in the first to sixth embodiments.

In the first to sixth embodiments described above, the existing floor slab 5 may be made of precast concrete (or may be a PCa floor slab). The existing floor slab 5 may be made of cast-in-place concrete. The existing floor slab 5 may be a steel floor slab, a synthetic floor slab, or the like.

In the above-described first to sixth embodiments, the new floor slab 7 may be a floor slab partially made of precast concrete, such as a half precast concrete floor slab. The new floor slab 7 may be made of prestressed concrete (or may be a PC floor slab). The new floor slab 7 may be a steel floor slab, a synthetic floor slab, or the like.

In the first to sixth embodiments described above, a bridge was used as an example of the "structure" of the present invention, but the "structure" of the present invention is not limited to bridges. For example, the "structure" of the present invention may be a tunnel having floor slabs.

The illustrated embodiments are merely illustrative of the present invention, and it goes without saying that the present invention includes various improvements and modifications made by those skilled in the art within the scope of the claims in addition to those directly indicated by the described embodiments.
Incidentally, the claims at the time of filing of Japanese Patent Application No. 2017-202222 were as follows.
[Claim 1]
A method for replacing a floor slab in a structure,
setting a plurality of construction areas by dividing the structure into a plurality of construction areas in the axial direction of the structure;
Each construction area has a multi-stage work process from the removal of the existing floor slab to the placement of the new floor slab,
A method for replacing floor slabs, wherein different work processes are performed in parallel in a construction area on the front side of the construction area and a construction area on the rear side of the construction area in the construction area on the front side of the construction area in the construction progress direction of floor slab construction along the axial direction of the structure.
[Claim 2]
2. The floor slab replacement method according to claim 1, wherein a plurality of work steps are performed in parallel so that work steps become later in order from the work area on the front side in the traveling direction to the work area on the rear side in the traveling direction.
[Claim 3]
carrying out the removed existing floor slab from the construction area forward in the traveling direction;
The floor slab replacement method according to claim 1 or 2, wherein the new floor slab is carried into the construction area from behind in the traveling direction.
[Claim 4]
The multi-stage work process that each construction area has,
a first work process for removing the existing floor slabs in the construction area;
a second work process for performing preparatory work for arranging a new floor slab in the construction area from which the existing floor slab has been removed;
a third work step of arranging a new floor slab in the construction area where the preparatory work has been performed;
The floor slab replacement method according to any one of claims 1 to 3, comprising
[Claim 5]
the structure is a bridge;
5. The floor slab replacement method according to claim 4, wherein the second work step includes providing a height adjusting material on the upper surface of the bridge girder of the bridge for adjusting the placement height of the new floor slabs placed in the construction area in the third work step.
[Claim 6]
the structure is a bridge;
The floor slab replacement method according to claim 4 or 5, wherein the second work step includes performing a scraping work on the upper surface of the bridge girder of the bridge.
[Claim 7]
The floor slab replacement method according to claim 6, wherein the cleaning work is performed in a temporary tent.
[Claim 8]
The floor slab replacement method according to any one of claims 1 to 7, wherein the welding work is performed in a temporary tent in the work process including the welding work among the work processes of the plurality of stages that each construction area has.
[Claim 9]
the structure is a bridge;
The floor slab replacement method according to any one of claims 1 to 8, wherein after the placement of the new floor slabs over the entire length of the bridge is completed, the new floor slabs and the bridge girders of the bridge are fixed and integrated, and the new floor slabs adjacent to each other in the axial direction of the bridge are fixed and integrated.
[Claim 10]
The floor slab replacement method according to any one of claims 1 to 9, wherein the new floor slab is made of precast concrete.

1 Bridge 2a, 2b Abutment 3 Bridge Pier 4 Bridge Girder 4a Upper Surface 4f Upper Flange 4w Web 5 Existing Floor Slab 5a Floor Slab Piece 5b Cutting Line 7 New Floor Slab 7a Through Hole 7b Lower Surface 9 Space 10 Temporary Tent 20, 30 Crane Device 21, 31 Lower Frame 22, 32 Gate Frame 23, 33 Upper Frame 24, 3 4 Lifting device 40 Carrier 50a, 50b Jack 51 Beam member 52 PC steel rod 53a, 53b Fixing member 60 Flange seal 70 Height adjustment member 80 Stud dowel A ₁ to A _k to _An construction area

Claims (12)

In a structure having a bridge girder, a method for replacing a floor slab arranged on the bridge girder from an existing floor slab to a new floor slab,
It has an existing floor slab removal process, a new floor slab placement preparation process, and a new floor slab placement process,
The existing floor slab removal step includes removing floor slab pieces of the existing floor slab,
The new floor slab placement preparation step includes preparing to place a new floor slab on the bridge girder from which the floor slab pieces have been removed, and the preparation work includes cleaning the upper surface of the bridge girder and installing height adjustment materials on the upper surface of the bridge girder.
The new floor slab placement step includes placing a new floor slab on the bridge girder for which the preparatory work has been performed,
setting a plurality of construction areas in the axial direction of the structure;
In the floor slab replacement construction progress direction along the axial direction, a first construction area in which the existing floor slab removal process is performed, a second construction area in which the new floor slab placement preparation process is performed, and a third construction area in which the new floor slab placement process is performed are arranged in order from the front side to the rear side of the direction of travel.
In the second construction area, in order from the front side to the rear side in the traveling direction, a cleaning work execution area where the cleaning work is performed and a height adjustment material installation work execution area where the height adjustment material installation work is performed.
A first crane device used in the existing floor slab removal process is positioned on the existing floor slab on the bridge girder,
A second crane device used in the new floor slab placement process is positioned on the floor slab newly installed on the bridge girder,
The first construction area, the second construction area, and the third construction area move forward in the direction of movement as the floor slab replacement construction progresses,
Carrying out the floor slab pieces forward in the traveling direction from the first crane device by a transport vehicle traveling on the existing floor slab on the bridge girder;
A floor slab replacement method, wherein the new floor slab is carried into the second crane device from behind in the direction of travel by a transport vehicle that travels on the floor slab newly installed on the bridge girder. The floor slab replacement method according to claim 1, wherein the cleaning work in the cleaning work execution area and the installation work of the height adjustment material in the height adjustment material installation work execution area are performed simultaneously. The floor slab replacement method according to claim 1 or 2, wherein the existing floor slab removal step in the first construction area and the new floor slab placement step in the third construction area are performed simultaneously. The floor slab piece is formed by cutting the existing floor slab,
The floor slab replacement method according to any one of claims 1 to 3, wherein the axial length of the second construction area is six times or more the axial length of the floor slab piece. The new floor slab is made of precast concrete or half precast concrete,
The floor slab replacement method according to any one of claims 1 to 3, wherein the axial length of the second construction area is at least six times the axial length of the new floor slab. The floor slab replacement method according to any one of claims 1 to 3, wherein the axial length of the second construction area is 12 m or more. In a structure having a bridge girder, a method for replacing a floor slab arranged on the bridge girder from an existing floor slab to a new floor slab,
It has an existing floor slab removal process, a new floor slab placement preparation process, and a new floor slab placement process,
The existing floor slab removal step includes removing floor slab pieces of the existing floor slab,
The new floor slab placement preparation step includes preparing to place a new floor slab on the bridge girder from which the floor slab pieces have been removed, and the preparation work includes cleaning the upper surface of the bridge girder and installing a seal on the upper surface of the bridge girder.
The new floor slab placement step includes placing a new floor slab on the bridge girder for which the preparatory work has been performed,
setting a plurality of construction areas in the axial direction of the structure;
In the floor slab replacement construction progress direction along the axial direction, a first construction area in which the existing floor slab removal process is performed, a second construction area in which the new floor slab placement preparation process is performed, and a third construction area in which the new floor slab placement process is performed are arranged in order from the front side to the rear side of the direction of travel.
In the second construction area, a cleaning work construction area for performing the cleaning work and a seal installation work construction area for performing the seal installation work are arranged in order from the front side to the rear side in the traveling direction,
A first crane device used in the existing floor slab removal process is positioned on the existing floor slab on the bridge girder,
A second crane device used in the new floor slab placement process is positioned on the floor slab newly installed on the bridge girder,
The first construction area, the second construction area, and the third construction area move forward in the direction of movement as the floor slab replacement construction progresses,
Carrying out the floor slab pieces forward in the traveling direction from the first crane device by a transport vehicle traveling on the existing floor slab on the bridge girder;
A floor slab replacement method, wherein the new floor slab is carried into the second crane device from behind in the direction of travel by a transport vehicle that travels on the floor slab newly installed on the bridge girder. The floor slab replacement method according to claim 7, wherein the cleaning work in the cleaning work execution area and the seal installation work in the seal installation work execution area are performed simultaneously. The floor slab replacement method according to claim 7 or 8, wherein the existing floor slab removal step in the first construction area and the new floor slab placement step in the third construction area are performed simultaneously. The floor slab piece is formed by cutting the existing floor slab,
The floor slab replacement method according to any one of claims 7 to 9, wherein the axial length of the second construction area is six times or more the axial length of the floor slab piece. The new floor slab is made of precast concrete or half precast concrete,
The floor slab replacement method according to any one of claims 7 to 9, wherein the axial length of the second construction area is six times or more the axial length of the new floor slab. The floor slab replacement method according to any one of claims 7 to 9, wherein the axial length of the second construction area is 12 m or more.