JP2014129664A - Method for installing caisson structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily install a frame for receiving a pipe pushed out to an arrival pit where a space of an opening corresponding to a caisson structure is formed.SOLUTION: A first movable frame 29a which receives a pipe 23 replaced with a caisson structure 10 and removed is assembled outside a space 22a and moved into the space to be installed, and a second immovable frame 29b is assembled and installed to be connected to the first frame 29a. After a pipe 23 pushed out to the side of an arrival pit 22 is received by the first frame 29a, the pipe is moved to the second frame 29b up to a position where the pipe does not interferes with a ceiling surface forming the space 22a, and then removed from the arrival pit 22.

Description

  The present invention relates to a method for installing a box structure, and in particular, traverses the box structure to a place other than the space under a route in which an opening space corresponding to the box structure is formed on the reach shaft side. The present invention relates to an effective technique applied to the installation method of the box structure in the box body propulsion method to be constructed.

  In order to construct a hollow box structure (for example, precast box culvert etc.) having a rectangular cross section under the route without obstructing the flow of a traveling train or car, the box propulsion method (for example, R & C method etc.) are used.

  In this box body propulsion method, a plurality of pipes having a hollow rectangular cross section are press-fitted along the direction crossing the route so that the planned construction position of the box structure and the outer surface are aligned. Keep it. Then, while the box structure is pushed from the start shaft side with the propulsion jack and the pipe is pushed out to the arrival shaft side, the box structure is replaced with the pipe and is constructed under the route. At this time, the pipe pushed out to the reach shaft side is placed on a frame that has been assembled to the reach shaft, and then lifted by a crane and removed.

  As a technique for installing the box structure, for example, there is one described in Japanese Patent Publication No. 63-31623.

Japanese Examined Patent Publication No. 63-31623

  Here, there is a case where an opening space corresponding to the box structure is formed on the reach shaft side under the line where the box structure is installed. In some cases, it is required to leave the space as it is and to install a box structure in other locations.

  In such a case, the roof part which comprises the space of the opening mentioned above becomes obstructive, and it becomes difficult to install the gantry in the reaching shaft.

  The present invention has been made from the technical background described above, and traverses the box structure at a location other than the space under the route in which an opening space corresponding to the box structure is formed on the reach shaft side. It is an object of the present invention to provide a technique capable of easily installing a pedestal for receiving a pipe pushed out to the reach shaft side in the box structure installation method in the box body propulsion method constructed as described above.

  In order to solve the above-mentioned problem, the installation method of the box structure of the present invention according to claim 1 is characterized in that the hollow box structure having a rectangular cross section is propelled from the starting shaft to the reaching shaft. Installation of a box structure in a box propulsion method constructed by crossing the box structure in a place other than the space under the route in which an opening space corresponding to the box structure is formed on the reach shaft side A pipe press-fitting step of press-fitting a plurality of pipes along a direction crossing the route so that a construction planned position and an outer surface of the box structure are aligned and aligned, and the box A first gantry assembly process for assembling a movable first gantry to receive the pipe that has been replaced by a structure and removed, and the first gantry assembly process assembled in the first gantry assembly process. At least a part of the mount A first pedestal moving step for moving and installing the first pedestal, and a second pedestal for receiving the pipe removed by replacing the box structure; A second pedestal installation step of assembling and installing so as to be connected to the first pedestal moved into the space in the step, and propelling the box structure from the start shaft side to push the pipe A box structure construction step for pushing the pipe structure to the reach shaft side and replacing the box structure with the pipe to construct the pipe structure under the route, and receiving the pipe pushed to the reach shaft side by the first frame. And a pipe removing step of moving from the first gantry to the second gantry to a position where the ceiling does not interfere with the ceiling surface forming the space and removing the pipe from the reaching shaft. .

  The installation method of the box structure of the present invention according to claim 2 is a method of propelling a hollow box structure having a rectangular cross section from a start shaft toward a reach shaft, so that the box body is provided on the reach shaft side. A method for installing a box structure in a box propulsion method for constructing the box structure by crossing the box structure at a location other than the space under the route in which an opening space corresponding to the structure is formed. A pipe press-in process in which a plurality of pipes are press-fitted along a direction crossing the route so that the planned construction position of the body structure and the outer surface are aligned and removed, and the box structure is replaced and removed. A first gantry assembling step for assembling a movable first gantry for receiving the pipes outside the space, and a part of the first gantry assembled in the first gantry assembling step. Move and install so that it is located in the space The first gantry moving step and the box structure are propelled from the start shaft side to push out the pipe to the reach shaft side, and the box structure is replaced with the pipe and constructed under the route. After the box structure construction process and the pipe pushed to the reach shaft side are received by the first mount, the first mount is moved to a position where it does not interfere with the ceiling surface forming the space. And a pipe removing step for removing from the reaching shaft.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein in the first gantry assembly step, the first gantry is assembled on a rail, and in the first gantry transfer step, The first pedestal that is assembled in the first pedestal assembling step and is on the rail is slid on the rail and moved into the space.

  According to the first aspect of the present invention, the first mount is assembled and moved and installed in the space formed on the reach shaft side, and the second mount is connected to the first mount and assembled. Therefore, it is possible to easily install a pedestal for receiving the pipe pushed out to the reach shaft side.

  According to the invention described in claim 2, since the first mount is assembled and moved and installed so that a part thereof is located in the space formed on the reaching shaft side, it is pushed out to the reaching shaft side. It is possible to easily install a frame for receiving the pipe.

  According to the third aspect of the present invention, the operation of moving the first frame into the space can be easily performed by sliding on the rail.

It is a perspective view which shows the box structure used with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows a one part process in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 2 in the R & C construction method which is one of the propulsion construction methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 3 in the R & C construction method which is one of the propulsion construction methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 4 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 5 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 6 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 7 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 8 in the R & C construction method which is one of the propulsion construction methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 9 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 10 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is explanatory drawing which shows the process following FIG. 11 in the R & C method which is one of the propulsion methods performed with the installation method of the box structure which concerns on one embodiment of this invention. It is the figure which looked at the promotion of a box-like structure from the side as an example of the state where the 1st frame and the 2nd frame were installed. It is the figure which looked at the mount frame from the reach shaft as an example of the state in which the 1st mount frame and the 2nd mount frame were installed. As an example of a state in which the first gantry and the second gantry are installed, FIG.

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  The box structure used in the present embodiment is, for example, a PRC (Pressed Reinforced Concrete) structure in which pre-stress is introduced into the upper and lower slabs, and has a hollow structure having a rectangular cross section as shown in FIG. And by building such a box structure in tandem and constructing an underground structure, it is used as a sewer, a conduit, a road underpass, an underground crosswalk, and the like.

  In FIG. 1, a box structure 10 includes an upper slab 10a and a lower slab 10b that face each other in the vertical direction, and a pair of side plates 10c and 10d that face each other at both ends of the upper slab 10a and the lower slab 10b. . The front and rear are opened as the opening 10e. And an underground structure is constructed | assembled by propelling the opening 10e mutually communicating and arranging the several box structure 10 in tandem.

  As shown in the drawing, fixing material insertion holes 10f extending along the propulsion direction are formed through the four corners of the box structure 10, and in the middle of the fixing material insertion holes 10f, the box structure 10 is provided. A notch groove 10g opened inside is formed.

  Further, a grout hole 10h for injecting a grout material after installation is formed through the center of the upper slab 10a, the lower slab 10b, and the side plates 10c, 10d. The box structure 10 has two types, that is, those in which the grout hole 10h is formed and those in which the grout hole 10h is not formed, and both are arranged at a predetermined ratio.

  Next, construction of an underground structure using such a box structure 10 will be described with reference to FIGS. Here, the construction of an underpass that traverses the track will be described. In this embodiment, the R & C method, which is one of the propulsion methods, is used.

  The underpass is provided perpendicular to the track 20 under a route such as the track 20.

  Here, in the present embodiment, as shown in FIG. 2, there are a pair of tracks 20a constituting a double line and a track 20b constituting a single line under the route on which the box structure 10 is installed. Under the track 20b, an opening space 22a corresponding to the box structure 10 is already formed. Then, the space structure 22 is left as it is, and the box structure 10 is installed at other locations (that is, below the track 20a).

  Note that the present invention can be applied not only to the case where such a space 22a is formed in advance on the arrival shaft 22 side, but also to the case where the arrival shaft 22 is excavated so that the space 22a is formed. Yes.

  Now, in order to construct an underpass, after the excavation shaft 21 is excavated by driving the retaining wall 25 into both grounds sandwiching the track 20a (if the arrival shaft 22 is not excavated in the state described above, the start shaft 21 And after the excavation of the reaching shaft 22 in which the space 22a is formed), the propulsion device 24 is used to cross the hollow rectangular cross section in the direction crossing the track 20a from the starting shaft 21 to the planned position of the planned underground passage. The shaped pipe 23 is press-fitted (pipe press-fitting process).

  The pipe 23 is press-fitted so that the planned construction position of the upper slab 10a of the box structure 10 and the outer surface are aligned with each other. In addition, the side surfaces 10c and 10d of the box structure 10 are also arranged so that the outer surfaces thereof are aligned and aligned. Furthermore, in order to reduce the resistance between the upper edge of the box structure 10 and the ground when propelling the box structure 10, the construction position of the upper slab 10 a of the box structure 10 matches the outer surface. The pipes 23 are also arranged on both sides of the pipes 23 arranged in a line (see FIG. 14).

  In many cases, a plurality of box structures 10 are arranged in tandem, so that the number of pipes 23 is also arranged in tandem according to the number of box structures 10, but in FIGS. The case where two are arranged in a column is shown. Further, in these drawings, the illustration of the pipe 23 press-fitted into the planned construction positions of the side plates 10c, 10d of the box structure 10 is omitted in order to avoid complicated display of the drawings.

  At this time, an excavator (not shown) such as an auger is inserted into the pipe 23 to excavate the ground below the surface of the track 20a, and the rear end of the pipe 23 is pressed by the propulsion device 24 to reach the reaching shaft 22. Press fit until it reaches. At this time, excavated earth and sand are carried out from behind through the inside of the pipe 23 by an auger screw.

  An FC (friction cut) plate 26 made of a strip steel plate substantially equal to the width and length of the pipe 23 is placed on the upper surface of the pipe 23 that is press-fitted into the planned construction position of the upper slab 10a of the box structure 10. Then, only the tip of the FC plate 26 is fixed to the tip of the pipe 23 by welding or screwing. After the pipe 23 is press-fitted, the fixing with the pipe 23 is released and the pipe 23 is fixed to the earth retaining wall 25.

  Such an operation is to eliminate the friction generated between the pipe 23 and the ground when the pipe 23 is propelled and replaced with the box structure 10 as described later.

  When the pipes 23 are constructed by completing the press-fitting of the pipes 23 penetrating from the start shaft 21 to the arrival shaft 22, as shown in FIG. 3, a propulsion base 27 is installed in the start shaft 21, and The box structure 10 with the blade 28 attached to the pipe group is placed. The cutting edge 28 cuts the ground where the pipe 23 is not press-fitted, and the front is pressed so that the ground is pressed and cut by being pressed from behind, so that the cut earth is taken into the cutting edge 28. Inclined inward.

  If the box structure 10 is placed on the propulsion table 27 in this way, a reaction force wall 31 is provided between the rear end surface of the box structure 10 and the rear end wall surface of the start shaft 21, and a plurality of reaction force walls 31 are provided. The propulsion jack 30 is installed.

  In addition, a pedestal 29 that receives the pipe 23 that has been removed by replacing the box structure 10 is installed in the reaching shaft 22.

  Here, as described above, in the present embodiment, an opening space 22a corresponding to the box structure 10 is formed on the reach shaft 22 side. Therefore, since there is a roof portion (where the track 20b exists) that constitutes the space 22a, it is difficult to assemble the gantry 29 installed in the reaching shaft 22.

  Therefore, as shown in the drawing, a rail 34 extending toward the start shaft 21 is laid in the reaching shaft 22. Then, the first mount 29a is assembled on the rail 34 positioned outside the space 22a (first mount assembly process). Therefore, the first mount 29a can move on the rail 34.

  If the first gantry 29a is assembled on the rail 34 located outside the space 22a in this way, as shown in FIG. 4, the rail 34 is arranged so that the first gantry 29a is located in the space 22a. It is slid and moved and installed (first pedestal relocation process). At this time, the first gantry 29a has an amount corresponding to the protruding space of the knives 28 so that the knives 28 attached to the tip of the box structure 10 do not interfere with the first gantry 29a when the knives 28 protrude into the reaching shaft 22. It is installed with a clearance from the retaining wall 25 only.

  Here, in order to prevent the first mount 29a from moving on the rail 34 at the installation position, the first mount 29a and the rail 34 or the ground are fixed using an anchor bolt or the like.

  In the case shown in the drawing, the entire first frame 29a may enter the space 22a, or a part of the first frame 29a may enter the space 22a. That is, as described above, when the first gantry 29a is installed in the space 22a with a clearance from the retaining wall 25 by the protruding space of the blade 28, the rear part in the moving direction is located outside the space 22a. May be.

  In the present embodiment, the first frame 29a is slid on the rail 34 and moved into the space 22a. However, as long as the first frame 29a can be moved, It is not limited to the moving form. However, if the rail 34 is used as in the present embodiment, the operation of moving the first mount 29a into the space 22a can be easily performed by sliding on the rail 34.

  Now, after the first frame 29a is installed in the space 22a, the second frame 29b is assembled and installed so as to be connected to the first frame 29a as shown in FIG. 2 frame installation process). At this time, the second mount 29b may be assembled on the rail 34 or on the ground, but even if assembled on the rail 34, the first mount 29a is fixed at the installation position. Therefore, the 2nd mount frame 29b is immovable.

  Here, FIG. 13 to FIG. 15 show details as an example of a state in which the first frame 29a and the second frame 29b are installed. 13 is a view of the propulsion of the box structure 10 as viewed from the side, FIG. 14 is a view of the gantry 29 viewed from the reaching shaft 22, and FIG. 15 is a diagram showing the gantry 29 installed through the plane. is there. In FIG. 13, the pipe 23 and the FC plate 26 are not shown.

  As shown in these drawings, the gantry 29 (the first gantry 29a and the second gantry 29b) is composed of a structural body in which H-shaped steel is combined, and the structural body is reinforced by braces (bars) 33 arranged appropriately. Has been.

  As shown in FIG. 13, a caster unit 29a-1 is attached to the bottom surface of the first mount 29a, and a caster (not shown) provided on the caster unit 29a-1 is mounted on the rail 34 described above. Is supposed to roll.

  Further, as shown in FIG. 14, the gantry 29 is a first receiving portion that receives the pipes 23 arranged in the lateral direction so that the planned construction position of the upper slab 10 a of the box structure 10 is aligned with the outer surface. 29-1 and a second receiving portion 29-2 for receiving the pipe 23 arranged in the vertical direction so that the construction planned positions of the side plates 10c, 10d of the box structure 10 and the outer surfaces thereof are aligned. ing. And the pipe 23 pushed out to the reach shaft 22 side as will be described later is received one by one in a row in the first receiving unit 29-1, and is collectively received in a column in the second receiving unit 29-2. .

  Now, when the installation of the first gantry 29a and the second gantry 29b is completed in this way (FIG. 5), the propulsion jack 30 is actuated as shown in FIG. When the box structure 10 is propelled from the start shaft 21 side while excavating, the pipe 23 moves to the arrival shaft 22 side. At the same time, the ground on the both side walls of the box structure 10 is cut by the blade 28, and the earth and sand are taken into the box structure 10, so that the box structure is further removed by the propulsion jack 30 while removing the earth and sand. The object 10 is pressed.

  At this time, since the FC plate 26 is fixed to the retaining wall 25, the sediment in the surface layer portion does not move even though the pipe 23 moves to the reaching shaft 22 side.

  If the box structure 10 is not buried in the ground even with the maximum propulsion stroke of the propulsion jack 30, the box structure 10 is propelled using the maximum propulsion stroke, and then the propulsion jack 30 is removed once and the reaction is performed. A strut 32 is installed on the force wall 31 side. Then, as shown in the drawing, the propulsion jack 30 is installed between the strut 32 and the box structure 10 again, and the propulsion of the box structure 10 is resumed.

  In this way, the first box structure 10 is propelled along the FC plate 26, and as shown in FIG. 7, the top pipe 23 is discharged to the reach shaft 22 side while cutting the internal soil and the box structure. While replacing with the object 10, the box structure 10-2 to be next constructed is installed behind the box structure 10-1 previously constructed.

  Note that the box structures 10 arranged in tandem are fixed to each other by a fixing material such as a PC steel rod or a PC steel wire, thereby preventing the box structures 10 from being displaced. This fixing work is performed between the box structure 10-1 previously constructed every time the box structure 10-2 to be constructed next is installed.

  Here, the pipe 23 pushed out to the reach shaft 22 by the propulsion of the box structure 10 is once received by the first mount 29a located in the space 22a (FIG. 6), and then located outside the space 22a. Is moved to the second frame 29b (FIG. 7). And it is lifted with the crane which is not illustrated, and is removed from the reaching shaft 22 (FIG. 8) (pipe removal process).

  If the leading pipe 23 is removed in this way, as shown in FIG. 9, the box structure to be next constructed is the same as the case of the box structure 10-1 previously constructed. The thing 10-2 is propelled and the next pipe 23 is pushed out to the arrival shaft 22 side. Here, the pipe 23 pushed out to the reaching shaft 22 is once received by the first frame 29a (FIG. 9), then moved to the second frame 29b (FIG. 10), and lifted by a crane to reach the reaching shaft. 22 is removed (FIG. 11) (pipe removal step).

  These series of operations are sequentially repeated, and finally the blade 28, the gantry 29, the propulsion jack 30, the reaction force wall 31, the strut 32, the rail 34, etc. are removed, as shown in FIG. The structures 10 are constructed in tandem to form an underpass (box structure construction process).

  As described above, according to the installation method of the box structure 10 in the present embodiment, the first gantry 29a is assembled and moved and installed in the space 22a formed on the reaching shaft 22 side, Since the second gantry 29b is connected to the first gantry 29a and assembled, the gantry 29 for receiving the pipe 23 pushed out toward the reaching shaft 22 can be easily installed.

  The pipe press-fitting process, the first gantry assembly process, the first gantry transfer process, the second gantry installation process, the pipe removal process, and the box structure construction process are performed in the order described above. The order is not limited, and any order may be used as long as the processes assumed when the processes are performed are performed.

  In the case described above, the first mount 29a is assembled and moved and installed in the space 22a, and the second mount 29b is connected to the first mount 29a for assembly. However, when the first gantry 29a is installed in the space 22a, when the portion located outside the space which is the rear end has a length necessary for lifting the pipe 23 with the crane, the first gantry 29a The installation of the gantry 29 in the reach shaft 22 is completed only by 29a, and it is connected to the first gantry 29a and the second gantry 29b becomes unnecessary.

  In this case, the assembled first mount 29a is moved and installed so that a part thereof is located in the space 22a. Further, if the box structure 10 is pushed from the start shaft 21 side and the pipe 23 is pushed out to the arrival shaft 22 side, the pushed pipe 23 is received by the first mount 29a, and then the space 22a is formed. The first base 29a is moved to a position where it does not interfere with the ceiling surface to be lifted, lifted with a crane and removed from the reaching shaft 22.

  Also by this, the first gantry 29a is assembled and moved and installed so that a part of the first pedestal 29a is located in the space 22a formed on the reaching shaft 22 side. Therefore, the pipe pushed to the reaching shaft 22 side. 23 can be easily installed.

  Although the invention made by the present inventor has been specifically described based on the embodiment, the embodiment disclosed in this specification is an example in all respects and is limited to the disclosed technology. Should not be considered. That is, the technical scope of the present invention should not be construed restrictively based on the description in the above-described embodiment, but should be construed according to the description of the scope of claims. All modifications are included without departing from the technical scope equivalent to the described technique and the gist of the claims.

  For example, in the above description, the case where the box structure 10 is pressed from the rear end side using the propulsion jack 30 has been described. However, the box structure 10 is pulled by embedding a steel wire from the reach shaft 22 side, etc. In other words, the box structure 10 may be promoted.

  In the above description, the case where the box structure installation method according to the present invention is used for the R & C method, which is one of the propulsion methods, is shown. However, other than the R & C method, for example, the SFT method, the FJ method, etc. It can be used for various propulsion methods.

10, 10-1, 10b-2 Box structure 10a Upper slab 10b Lower slab 10c, d Side plate 10e Opening 10f Fixing material insertion hole 10g Groove 10h Grout hole 20 Track 21 Starting shaft 22 Reaching shaft 23 Pipe 24 Propeller 25 Earth retaining Wall 26 FC plate 27 Propulsion base 28 Cutting edge 29 Base 29-1 First receiving portion 29-2 Second receiving portion 29a First base 29a-1 Caster unit 29b Second base 30 Propulsion jack 31 Reaction wall 32 struts 33 braces 34 rails

Claims (3)

By propelling a hollow box structure having a rectangular cross section from the starting shaft to the reaching shaft, other than the space under the line in which an opening space corresponding to the box structure is formed on the reaching shaft side A box structure installation method in a box propulsion method for building the box structure across the box,
A pipe press-fitting step of press-fitting a plurality of pipes along a direction crossing the line, so that the construction planned position and the outer surface of the box structure are aligned with each other;
A first gantry assembling step of assembling a movable first cradle for receiving the pipe removed by replacing the box structure outside the space;
A first gantry moving step of installing the first gantry assembled in the first gantry assembling step so that at least a part thereof is located in the space; and
The second frame that cannot move and receives the pipe that has been replaced by the box structure is connected to the first frame that has been moved into the space in the first frame moving step. A second pedestal installation step for assembling and installing;
A box structure construction step of propelling the box structure from the start shaft side to push the pipe to the arrival shaft side, replacing the box structure with the pipe and building under the route,
After the pipe pushed out to the reach shaft side is received by the first gantry, the pipe is moved from the first gantry to the second gantry to a position where it does not interfere with the ceiling surface forming the space. A pipe removing step for removing from the shaft,
A method for installing a box structure, comprising: By propelling a hollow box structure having a rectangular cross section from the starting shaft to the reaching shaft, other than the space under the line in which an opening space corresponding to the box structure is formed on the reaching shaft side A box structure installation method in a box propulsion method for building the box structure across the box,
A pipe press-fitting step of press-fitting a plurality of pipes along a direction crossing the line, so that the construction planned position and the outer surface of the box structure are aligned with each other;
A first gantry assembling step of assembling a movable first cradle for receiving the pipe removed by replacing the box structure outside the space;
A first gantry moving step of moving and installing the first gantry assembled in the first gantry assembling step so that a part thereof is located in the space;
A box structure construction step of propelling the box structure from the start shaft side to push the pipe to the arrival shaft side, replacing the box structure with the pipe and building under the route,
After receiving the pipe pushed out to the reaching shaft side by the first mount, the pipe is moved on the first mount to a position where it does not interfere with the ceiling surface forming the space and removed from the reaching shaft Removal process,
A method for installing a box structure, comprising: In the first mount assembly step, the first mount is assembled on a rail;
In the first gantry relocation step, the first gantry assembled on the rail in the first gantry assembling step is slid on the rail and moved into the space.
The box structure installation method according to claim 1 or 2, wherein the box structure is installed.

Images