JP6826956B2 - Dismantling method - Google Patents

Description

The present invention relates to a method of dismantling a support work.

When constructing a structure such as a pier in a water area, a temporary deadline such as a steel pipe sheet pile is placed in a well-shaped cylinder to close the water area, and the ground inside the water area is excavated to a predetermined depth and dried up. May be built.

A support work is installed inside the well cylinder with the temporary deadline to resist the surrounding water pressure (see, for example, Patent Documents 1-3). Support works will be removed according to the construction of the structure.

Japanese Unexamined Patent Publication No. 4-155010 Patent No. 2949341 Patent No. 3051321

At present, various measures are required to improve the workability of such temporary deadline work and to carry out the work quickly. For example, the dismantling work of the support work has conventionally been troublesome, and there is also a problem in terms of safety.

In particular, the applicant has proposed a temporary demolition structure using a support unit having a truss structure on a flat surface and a vertical surface in Japanese Patent Application No. 2016-106158, and by using such a highly rigid support unit, the support unit A large opening can be formed inside the structure, which improves the workability when constructing a structure, but there has been no established method for dismantling such a support unit.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a dismantling method capable of easily dismantling a support work.

The present invention for solving the above-mentioned problems is a dismantling method for dismantling a support unit made of steel material installed inside a temporary cut-off body that closes a water area after drying up the inside of the temporary cut-off body. The support unit has a truss structure on a flat surface and a vertical surface, and when the support unit is disassembled, the support unit is disassembled as a member having a truss shape on both the flat surface and the vertical surface, and the member is disassembled. It is a dismantling method characterized by being removed.

In the present invention, the support unit can be efficiently and easily disassembled and removed, and the construction period can be shortened by removing the above support unit into members having a truss shape on both a flat surface and a vertical surface. ..

A part or all of the cross section of the steel material of the support unit is cut and removed, the support unit is deformed to reduce the axial force generated in the support unit, and then the support unit is disassembled. Is desirable.
In the present invention, after removing the axial force generated in the steel material of the support unit by the above procedure, the support unit is disassembled and removed. As a result, when the support unit is disassembled, it is not deformed unexpectedly due to its axial force, so that the support unit can be safely disassembled.

It is desirable to dismantle the support unit while it is supported by a support mechanism.
By disassembling the support unit while being supported by the support mechanism in this way, the support unit arranged in the hollow inside the temporary cutoff body can be disassembled without losing the balance or dropping.

For example, when the support unit is installed up and down, the lower support unit is disassembled and removed, the upper support unit is disassembled and removed, and the lower support unit is disassembled. , The lower support unit is dismantled as a member that does not have a truss shape or has a truss shape only on a flat surface or a vertical surface, the member is removed, and the upper support unit is dismantled. At this time, the upper support unit is disassembled as a member having a truss shape on both a flat surface and a vertical surface, and the member is removed.
In this case, the lower support unit is disassembled as described above so that the disassembled members can be carried upward through the upper support unit. The upper support unit can be disassembled and removed efficiently as described above, and the construction period can be shortened.

Alternatively, the support units are installed one above the other, and after the upper support unit is disassembled and removed, the lower support unit is disassembled and removed, and the upper and lower support units are disassembled and removed. At the time of dismantling, the support unit is dismantled as a member having a truss shape on both a flat surface and a vertical surface, and the member is removed.
In this case, there is no obstacle when the upper and lower support units are dismantled, and the dismantled members can be dismantled and efficiently removed by a large dismantling method, which leads to further shortening of the construction period.

It is desirable that the lower support unit is disassembled while being supported from below by a support base which is a support mechanism. Further, it is desirable that the support unit in the upper stage is disassembled while being supported from the upper end portion of the temporary cutoff body by a connecting member which is a support mechanism.
In this way, the lower support unit can be suitably supported from below by using a support base as the support mechanism, and the upper support unit can be temporarily supported by using a connecting material as the support mechanism. It can be suitably supported from the upper end of the deadline.

A filling material is arranged between the support unit and the temporary cutoff body, and it is also desirable to reduce the axial force generated in the support unit by removing the filling material.
In this case, the axial force can be released without cutting the steel material.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a dismantling method capable of easily dismantling a support work.

The figure explaining the deadline of the water area 3. The figure explaining excavation of ground 2. The figure which shows the truss support 1 and the support unit 10. The figure explaining the installation of the support work unit 10. The figure explaining the disassembly of the lower support unit 10. The figure explaining the dismantling of the support work unit 10 in the upper stage. The figure explaining the reduction of the axial force of the support work unit 10. The figure explaining the reduction of the axial force of the support work unit 10. The figure explaining the small disassembly of the support work unit 10. The figure explaining the large disassembly of the support work unit 10. The figure explaining the dismantling of the upper and lower support work units 10. The figure explaining the reduction of the axial force of the support work unit 10.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

In the embodiment of the present invention, a temporary deadline for a water area is made by a temporary deadline such as a steel pipe sheet pile, a support unit is installed inside the temporary deadline, and then the support unit is installed when a structure is constructed inside the temporary cutoff body. An example of dismantling will be described.

In the present embodiment, as shown in FIG. 1A, a steel pipe sheet pile 4 which is a temporary cutoff body is first driven into the ground 2 at the bottom of the water to form a closed region on a flat surface, and the water area 3 to be constructed is closed. .. The steel pipe sheet pile 4 is provided in a well-shaped shape as shown in FIG. 1 (b). FIG. 1 (b) is a view of FIG. 1 (a) from above.

In this example, the steel pipe sheet pile 5 is driven into the ground 2 on the bottom of the water to form a partition wall inside the well cylinder made of the steel pipe sheet pile 4. The steel pipe sheet piles 5 are provided in a row so as to connect a pair of opposite sides of the wells formed by the steel pipe sheet piles 4. If necessary, concrete by arranging reinforcing bars in the steel pipe in a predetermined section in the vertical direction of the steel pipe sheet piles 4 and 5 (for example, the section from the top plate concrete to the vicinity of the paving stone layer and the lower end of the steel pipe sheet piles 4 and 5 described later). It is also possible to reinforce by filling with concrete. Although not shown, the adjacent steel pipe sheet piles 4 and 5 are connected to each other by a joint, and the joint portion of the steel pipe sheet pile 4 forming the well is water-stopped.

The steel pipe sheet piles 4 and 5 are driven by using the guide frame 6. The guide frame 6 has an outer frame 6a arranged along the outer circumference of the well by the steel pipe sheet pile 4, and two inner frames 6b arranged along both sides of the inner circumference of the well by the steel pipe sheet pile 4 and the partition wall by the steel pipe sheet pile 5. Consists of. A diagonal member 61 is arranged at a corner of each inner frame 6b. After placing the steel pipe sheet piles 4 and 5, the guide frame 6 is attached to the tops of the steel pipe sheet piles 4 and 5.

After that, as shown in FIG. 2, the ground 2 inside the well cylinder by the steel pipe sheet pile 4 is excavated underwater to a predetermined depth while maintaining the water level, and the paving stone layer 71 and the bottom concrete 72 are constructed at the excavation bottom. Underwater excavation is carried out by installing an excavator such as a grab on the crane of a dredger (not shown). After excavating the ground 2 and placing the bottom concrete 72, the steel pipe sheet pile 5 is cut at a position corresponding to the upper surface of the bottom concrete 72, and the upper portion thereof is removed.

In the present embodiment, the excavation of the ground 2 is performed with the guide frame 6 left, and after the excavation, the inner frame 6b is removed so as not to hinder the installation of the support work described later. As a result, when excavating the ground 2, the guide frame 6 functions as a reinforcing work for suppressing deformation of the steel pipe sheet pile 4 with respect to wakes generated by ships navigating in the vicinity. After the bottom concrete 72 is constructed and the inner frame 6b is removed, the steel pipe sheet pile 4 is held by the outer frame 6a and the bottom concrete 72 to suppress deformation of the steel pipe sheet pile 4.

In the present embodiment, after that, a support unit is installed inside the steel pipe sheet pile 4 in order to resist the surrounding water pressure. As the support unit, the truss support 1 whose plane is shown in FIG. 3A is used.

The truss support 1 has a substantially square-shaped annular plane, and has a large-area opening 15 at the center. The plane of the truss support 1 has a truss structure in which a plurality of vertical members 11 and horizontal members 12 are combined in a grid pattern and diagonal members 14 are provided in the grid. The diagonal members 14 are also provided at the four corners of the opening 15. If necessary, a separate beam member such as a box beam is also provided so as to bridge the inside of the opening 15.

In the present embodiment, as shown in FIG. 3B, the two-stage truss support 1 is vertically connected and supported by a truss structure in which horizontal members 18 are provided above and below the plurality of vertical members 16 and diagonal members 17. Used as a work unit 10. The support unit 10 is assembled and manufactured in advance on the ground or on the water.

The diagonal members 17 are arranged in a substantially X shape between adjacent vertical members 16. The plane of the horizontal member 18 has a rectangular frame shape. Steel materials such as H-shaped steel are used for the vertical member 16, the diagonal member 17, the horizontal member 18, and the vertical member 11, the horizontal member 12, and the diagonal member 14.

In the present embodiment, the support unit 10 is carried to the site, suspended from a crane or the like of a hoisting vessel, suspended inside the steel pipe sheet pile 4, and supported inside the steel pipe sheet pile 4 as shown in FIG. 4A. The work unit 10 is hung and lowered.

The support unit 10 is carried to the site by a pontoon, and the support unit 10 is suspended via a grid-shaped suspension frame (not shown). When the support unit 10 is suspended inside the steel pipe sheet pile 4, a guide material such as H-shaped steel is provided at the upper end of the steel pipe sheet pile 4 as needed to guide the support unit 10. The wire attached to the support unit 10 is operated with a winch such as a chill hole for positioning when the support unit 10 is loaded on the pontoon by a crane or when the support unit 10 is suspended inside the steel pipe sheet pile 4. You can also do it.

In the present embodiment, when the support unit 10 is lowered inside the steel pipe sheet pile 4, a rod-shaped support member 7 is attached to the outer peripheral portion of the support unit 10 as shown in FIG. 4A. A fully screwed steel rod is used for the support member 7, and the support member 7 is arranged so as to be inclined inward as it goes downward.

In the present embodiment, the support unit 10 is lowered to a predetermined position as shown in FIG. 4B while sequentially adding a plurality of steel rods as the support material 7 with a coupler or the like. The position (depth) of the support unit 10 can be grasped from the measuring tape (not shown) attached to the support unit 10, the length and number of the added steel rods, and the like.

When the support unit 10 is lowered, spacers (not shown) for positioning on the plane of the support unit 10 are attached to the outside of each side of the outer peripheral portion of the truss support 1 above the support unit 10. be able to.

When the support unit 10 is arranged at a predetermined position, the upper end portion of the support member 7 is held by the support member receiving portion 9 provided at the upper end of the steel pipe sheet pile 4. The support material receiving portion 9 has a center hole jack 91 and the like, and the support material 7 is held by the center hole jack 91 to adjust the tension force thereof, and the support support unit 10 is suspended and supported.

Regarding the above-mentioned addition of steel rods and installation of the support material receiving portion 9, a temporary scaffold (not shown) is provided in advance at the upper end of the steel pipe sheet pile 4, and the work is performed there. Further, since the center hole jack 91 is a heavy object, the installation work can be performed by attaching the chain block to a frame (not shown) provided at the upper end of the steel pipe sheet pile 4 and suspending the center hole jack 91. ..

In the present embodiment, the support unit 10 is supported by the support material 7 from a plurality of locations (for example, about 20 locations). The tension force of the support member 7 at this time is controlled so as not to exceed the control value, and is finally adjusted to an appropriate value.

As a result, the support unit 10 is arranged in an annular shape along the inner circumference of the well cylinder by the steel pipe sheet pile 4. Next, in the present embodiment, as shown in FIG. 4C, a new support unit 10 is suspended from a crane or the like of a hoisting vessel and suspended inside the steel pipe sheet pile 4 in the same manner as described above. It is hung inside 4 and lowered. When the support unit 10 is lowered, spacers (not shown) similar to the above can be attached to the outside of each side of the outer peripheral portion of the lower truss support 1.

As shown in FIG. 4C, a hook-shaped hooking material 19 made of a steel material such as H-shaped steel is provided on the upper part of the support unit 10, and the upper part of the hooking material 19 is placed on the upper end of the steel pipe sheet pile 4. It is hooked and fixed to the mounting material (not shown) provided at the upper end by welding or the like. The mounting material is, for example, a steel material such as H-shaped steel, and is fixed in the steel pipe by welding or the like. As a result, the upper support unit 10 can be supported, and it is not necessary to attach a bracket or the like for supporting the support unit 10 to the inside of the steel pipe sheet pile 4 by underwater welding, which leads to shortening of the construction period.

After that, when the truss support 1 of each stage and the steel pipe sheet pile 4 are padded with a filling material such as concrete, the two upper and lower support units 10 are annularly formed along the inner circumference of the well cylinder by the steel pipe sheet pile 4. The arranged temporary deadline structure 20 is formed.

After forming the temporary deadline structure 20 in this way, the construction of the structure is started. In this embodiment, the pier is constructed on the top slab concrete as a structure. The support unit 10 is removed according to the progress of construction of the structure.

Here, as shown in FIG. 4D, first, the inside of the well cylinder is drained by the steel pipe sheet pile 4 to dry up, and the bracket 8 is attached at a position corresponding to the truss support 1 of each stage.

After that, as shown in FIG. 5A, a reinforced concrete top slab concrete 73 is constructed on the bottom concrete 72, and the lower support unit 10 is mounted on the top slab concrete 73 by the support base 31 (support mechanism). To support. A jack or the like is used for the support base 31.

In the present embodiment, after that, the lower support unit 10 is disassembled. However, since pressure such as water pressure is transmitted from the steel pipe sheet pile 4 to the support unit 10 via the filling material, an axial force (compressive force or tensile force) is generated in each steel material of the support unit 10. If dismantling is performed as it is, there is a risk in terms of safety because the support unit 10 is unexpectedly deformed due to the axial force.

Therefore, in the present embodiment, as shown in FIG. 7A, the entire cross section (cross section) of the steel material is formed at the cut points 111 at both ends of the diagonal members 14 (flint) at the four corners of the opening 15 of the truss support 1 of the support unit 10. The diagonal member 14 (steel material) is removed by cutting. The "cross section" refers to a cross section in a direction orthogonal to the longitudinal direction of the steel material. Further, when another beam member such as a box beam is bridged over the opening 15, this is also cut and removed in the same manner. As a result, the support unit 10 is bent and deformed inward with respect to the pressure transmitted from the steel pipe sheet pile 4, and the force is released to reduce the axial force of the steel material.

Further, in the present embodiment, a part of the cross section of the steel material of the vertical member 11 and the horizontal member 12 is cut at the notch 112 near the center of each side of the plane of the support unit 10 shown in FIG. By removing (notch), the axial force of the support unit 10 is further reduced due to the buckling deformation of the remaining portion.

For example, in the case of H-section steel, the flange portions on both sides of the web can be cut out and removed as shown by the dotted line portion in the left figure of FIG. 8A, and the web can be buckled and deformed as shown in the right figure. In the case of the steel material (raised) on the outer periphery of the truss support 1, one flange and the web are cut out in a T shape and removed as shown by the dotted line in the left figure of FIG. 8 (b). , The other flange can be buckled and deformed as shown in the right figure.

After releasing the axial force of the steel material of the support unit 10 in this way, in the present embodiment, as shown in FIGS. 5 (b) to 5 (d), the truss support 1 at the upper part of the support unit 10 and the truss support 1 above and below The truss structure between them and the truss support 1 at the bottom are dismantled in this order. The disassembled member 101 is sequentially carried out upward through the opening 15 (see FIG. 3A) of the upper support unit 10 using a crane or the like. In this way, the lower support unit 10 is dismantled.

When the lower support unit 10 is dismantled, the support unit 10 is disassembled in consideration of carrying the disassembled member 101 upward through the opening 15 of the upper support unit 10.

For example, as shown in FIG. 9A, the cutting points 111 and the like at both ends of the steel material constituting the truss structure are cut, and the linear member 101 (which does not have the truss shape) after cutting is removed, or FIG. 9 As shown in (b) and (c), the cut portion 111 or the like corresponding to the intersection of the steel materials is cut, and the cut member 101 has a truss shape (triangular shape) only in the plane or in the vertical plane. Remove this. The support base 31, the bracket 8, and the like that are no longer needed due to the dismantling of the lower support unit 10 are removed in accordance with the removal of the lower support unit 10.

In the present embodiment, after that, as shown in FIG. 6A, a reinforced concrete pier 74 is constructed on the top slab concrete 73, and the periphery of the pier 74 is backfilled with earth and sand. The pier 74 is constructed inside the opening 15 of the upper support unit 10.

The upper support unit 10 is dismantled at an appropriate time after the lower support unit 10 is dismantled. Here, as shown in FIG. 6A, it is assumed that the inside of the well cylinder made of the steel pipe sheet pile 4 is backfilled with earth and sand and then dismantled.

When the upper support unit 10 is disassembled, the upper support unit 10 is supported from the upper end of the steel pipe sheet pile 4 by a connecting member 41 (support mechanism) so that the support unit 10 does not become unstable. In addition, since there are no obstacles on the upper support unit 10, unlike the lower support unit 10, it can be disassembled in large pieces, and the disassembled members can be sequentially carried upward using a crane or the like. It is possible.

At the time of dismantling the support unit 10, after removing the axial force by the same procedure as in FIG. 7, as shown in FIG. 10, the portion corresponding to the intersection of the steel materials constituting the truss structure is cut as the cutting portion 111, and after cutting. With the member 102 having a truss shape both in the plane and in the vertical plane (large disassembly), the members 102 are collectively removed by a crane or the like. The connecting member 41 is also removed when it is no longer needed due to the removal of the member 102.

In this way, as shown in FIG. 6 (b), the upper support unit 10 is removed, and when the unnecessary bracket 8 and the like are also removed, water is injected into the well cylinder by the steel pipe sheet pile 4 as shown in FIG. 6 (c). Then, the steel pipe sheet pile 4 and the like are removed. As shown in FIG. 6D, the steel pipe sheet pile 4 is cut at a position corresponding to the upper surface of the top slab concrete 73 and only the upper portion thereof is removed, so that the remaining part is used as a pier foundation together with the steel pipe sheet pile 5. It is possible.

As described above, in the present embodiment, when the upper support unit 10 is disassembled, the support unit 10 is largely separated into members 102 having a truss shape on both a flat surface and a vertical surface and removed. , The support unit 10 can be disassembled and removed efficiently and easily, and the construction period can be shortened.

Further, in the present embodiment, after the axial force of the steel material of the support work unit 10 is released by the procedure described with reference to FIG. 7, the support work unit 10 is disassembled and removed. As a result, when the support unit 10 is disassembled, it is not deformed unexpectedly due to its axial force, so that the support unit 10 can be safely disassembled.

Further, in the present embodiment, the support unit 10 is disassembled while being supported by the support base 31 and the connecting member 41, which are support mechanisms, so that the support unit 10 is arranged in the hollow inside the steel pipe sheet pile 4. It can be disassembled without losing balance or dropping it. Further, the lower support unit 10 can be suitably supported from below by using the support base 31, and the upper support unit 10 can be preferably supported from the upper end of the steel pipe sheet pile 4 by using a connecting member 41. it can. However, the support mechanism is not limited to these.

Further, in the present embodiment, the lower support unit 10 is disassembled into small pieces as described above so that the disassembled members can be carried upward through the upper support unit 10. The upper support unit 10 can be disassembled and removed efficiently as described above, and the construction period can be shortened.

However, the present invention is not limited to this. For example, the timing of dismantling the upper and lower support units 10 or the dismantling order is not limited to the above.

That is, as shown in FIG. 11A, after the inside of the well cylinder by the steel pipe sheet pile 4 is dried up, the bridge pier 74 is constructed inside the opening 15 of the upper and lower support unit 10, and then the bridge pier 74 is constructed. As shown in (c), it is also possible to disassemble the upper support unit 10 and the lower support unit 10 in this order. After dismantling these support units 10, the inside of the well cylinder made of the steel pipe sheet pile 4 is backfilled with earth and sand as shown in FIG. 11D, and water is injected.

In this case, when the upper and lower support units 10 are dismantled, there is no obstacle when the dismantled member 102 is carried out upward by a crane or the like, and the members can be disassembled and efficiently removed by a large disassembly method. It leads to shortening of construction period. Although not particularly shown, when the upper and lower support units 10 are disassembled, the support by the connecting member 41 and the support base 31 can be similarly performed.

Further, in the present embodiment, when the support unit 10 is deformed, the diagonal members 14 at the four corners of the opening 15 are first cut and removed, but the present invention is not limited to this, and members that may be cut or removed may be cut or removed. Anything can be used as long as it can cause the support unit 10 to be deformed. Further, in the present embodiment, cutting and removal of the entire cross section of the steel material as described in FIG. 7A and cutting (notch) of a part of the cross section as described in FIG. 7C are used in combination. However, the support unit 10 may be deformed by only one of them to reduce the axial force.

Further, the steel pipe sheet pile 4 need only form a closed region on a flat surface, and is not limited to the one that closes the water area 3 in a well-shaped manner. For example, the water area 3 may be closed in a cylindrical shape. In this case, the plane of the support unit 10 may be a substantially circumferential annular plane. Further, instead of the steel pipe sheet pile 4, a steel sheet pile or other member may be used as a temporary cutoff body.

Further, in the present embodiment, the steel material was cut when the axial force of the support unit 10 was released, but as shown in FIG. 12, the filling material 50 such as concrete between the steel pipe sheet pile 4 and the truss support 1 was removed. You may. In this case, the axial force of the support unit 10 can be relaxed without cutting the steel material. However, since it takes time, it is desirable to remove the filling material 50 only in the necessary portion in combination with the cutting of the steel material described above. Alternatively, a sand bag or the like may be used for the packing material 50 so that the axial force can be released in a short time simply by making a hole in the bag and removing the sand. In addition, although it takes time and effort, it is also possible to bite a jack in advance between the steel materials of the support unit 10 and shrink the jack instead of cutting the steel material when the axial force is released.

Further, in the present embodiment, the support unit 10 in which the upper and lower two-stage truss support 1 is connected by the truss structure is used, but the present invention is not limited to this. For example, it is possible to connect three or more stages of truss support 1 vertically by a truss structure, and dismantling can be performed by the same method as described above.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

1: Truss support 2: Ground 3: Water area 4: Steel pipe sheet pile 5: Steel pipe sheet pile 6: Guidance frame 7: Support material 8: Bracket 9: Support material receiving part 10: Support work unit 11: Vertical material 12: Horizontal material 14 , 17, 61: Diagonal material 15: Opening 16: Vertical material 18: Horizontal material 19: Hook material 20: Temporary deadline structure 31: Support stand 41: Connecting material 50: Filling material 71: Paving stone layer 72: Bottom concrete 73: Top plate concrete 74: Bridge pier 91: Center hole jack 111: Cutting part 112: Notch part

Claims (8)

This is a dismantling method in which a support unit made of steel material installed inside a temporary cut-off body that shuts off a water area is dismantled after the inside of the temporary cut-off body is dried up.
The support unit has a truss structure in flat and vertical planes.
A dismantling method characterized in that when dismantling the support unit, the support unit is disassembled as a member having a truss shape on both a flat surface and a vertical surface, and the member is removed. A part or all of the cross section of the steel material of the support unit is cut and removed, the support unit is deformed to reduce the axial force generated in the support unit, and then the support unit is disassembled. The dismantling method according to claim 1, characterized in that. The dismantling method according to claim 1 or 2, wherein the support unit is disassembled while being supported by a support mechanism. The support unit is installed up and down,
After dismantling and removing the support unit in the lower row, the support unit in the upper row is dismantled and removed.
When dismantling the lower support unit, the lower support unit is dismantled as a member that does not have a truss shape or has a truss shape only on a flat surface or a vertical surface, and the member is removed. ,
Claim 1 according to claim 1, wherein when the upper support unit is disassembled, the upper support unit is disassembled as a member having a truss shape on both a flat surface and a vertical surface, and the member is removed. The dismantling method according to any one of item 3. The support unit is installed up and down,
After dismantling and removing the support unit in the upper row, the support unit in the lower row is dismantled and removed.
Claim 1 according to claim 1, wherein when the upper and lower support units are disassembled, the support unit is disassembled as a member having a truss shape on both a flat surface and a vertical surface, and the member is removed. The dismantling method according to any one of item 3. The dismantling method according to any one of claims 4 or 5, wherein the support unit in the lower stage is disassembled while being supported from below by a support base which is a support mechanism. The dismantling method according to any one of claims 4 to 6, wherein the support unit in the upper stage is disassembled while being supported from the upper end portion of the temporary cutoff body by a connecting member which is a support mechanism. .. A filling material is arranged between the support unit and the temporary deadline.
The dismantling method according to any one of claims 1 to 7, wherein the axial force generated in the support unit is reduced by removing the packing material.

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