Net support device and method for dismantling large structures using the net support device

Abstract

To provide a net support device that is easy to handle and applicable to a large-sized structure, and a demolition method for the large-sized structure using the net support device.SOLUTION: A net support device 100 for supporting a net 50 covering a large-sized structure S to be demolished, comprises: a vertical material 10 which is installed around the large-sized structure S; metal fittings 20 which are fitted detachably to the vertical material 10; first members 30 which extend along a length direction of the vertical material 10, and are fitted detachably to the vertical material 10 through the metal fittings 20; and second members 40 which extend along the first members 30 and are locked so that vertical positions are freely changed relative to the first members 30 to support the net 50.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a net support device and a method for dismantling a large structure using the net support device. [Background technology]

[0002] At demolition sites of structures, anti-scattering nets are often installed to prevent objects from scattering outside the structure. The anti-scattering nets are required to be easily movable downwards as the structure is dismantled. For example, the net support device described in Patent Document 1 has a first member attached to a scaffolding set up around the structure to be demolished, and the first member supports a second member supporting the scattering prevention net so that the second member can move relatively in the vertical direction. This makes it possible to easily move the scattering prevention net downward by moving the second member downward in accordance with the demolition of the structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-67542 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional net support device, when the structure is large, for example, the distance between the second members supporting the scatter prevention net and the structure becomes long. When the distance becomes long, the load acting from the scatter prevention net increases, and depending on the scaffolding, the scatter prevention net may not be able to be supported. In view of the problems in the background art described above, an object of the present invention is to provide a net support device that is easy to handle and can accommodate large structures, and a method for dismantling a large structure using the net support device. [Means for solving the problem]

[0005] The gist of the present invention is as follows.

[0006] <1> The net support device of aspect 1 of the present invention is a net support device that supports a net covering a large structure to be dismantled, and comprises a plurality of vertical members installed around the large structure, a first member extending along the longitudinal direction of the vertical members and removably attached to the vertical members, and a second member extending along the first members and engaged with the first members so that its vertical position can be freely changed, and supporting the net.

[0007] <2> A net support device according to a second aspect of the present invention is the net support device according to the first aspect, wherein the vertical members are H-shaped steel members.

[0008] <3> A net support device according to aspect 3 of the present invention is a net support device according to aspect 1 or aspect 2, wherein the net comprises a rope and a mesh portion supported by the rope, and the second member has a rope tension support portion that supports the tension of the rope and a rope middle support portion that supports the middle of the rope so that it can slide freely, and is provided with a tension adjustment device that connects between the end of the rope and the rope tension support portion and can change the distance between the end of the rope and the rope tension support portion.

[0009] <4> A net support device according to aspect 4 of the present invention is a net support device according to any one of aspects 1 to 3, wherein the first member is a groove-shaped member having an approximately C-shaped groove-shaped cross-section, and the second member is a tubular member having a closed cross-section.

[0010] <5> A net support device according to aspect 5 of the present invention is a net support device according to any one of aspects 1 to 4, further comprising a mounting bracket that is removably attached to the vertical member, and the first member is attached to the vertical member via the mounting bracket.

[0011] <6> A net support device according to a sixth aspect of the present invention is the net support device according to the fifth aspect, in which the position of the first member relative to the mounting fixture is changeable.

[0012] <7> A method for dismantling a large structure according to aspect 7 of the present invention is a method for dismantling the large structure using a net support device according to any one of aspects 1 to 6, and includes a vertical member installation process for installing a pair of vertical members facing each other on either side of the large structure, a net support device attachment process for attaching each component of the net support device, except for the vertical members, to each of the pair of vertical members, and a sliding process for sliding the second member downward relative to the first member.

[0013] <8> A method for dismantling a large structure according to aspect 8 of the present invention is the method for dismantling a large structure according to aspect 7, further comprising a transfer process in which the first member and the mounting bracket are removed from the vertical member, moved downward, and attached to the vertical member.

[0014] <9> A method for dismantling a large structure according to aspect 9 of the present invention is a method for dismantling a large structure according to aspect 7 or aspect 8, wherein the first member comprises an upper first member and a lower first member arranged below the upper first member along the axis of the upper first member, the net support device mounting process includes a separate installation process for mounting the upper first member and the lower first member to the vertical member, and the sliding process includes a locking process for sliding the second member downward from the upper first member until it fits into the lower first member, and then locking the second member to the lower first member.

[0015] <10> A method for dismantling a large structure according to aspect 10 of the present invention is a method for dismantling a large structure according to any one of aspects 7 to 9, and includes a rope tensioning process in which a rope is stretched between a pair of vertical members via the second member, a relaxation process in which the tension of the rope is reduced before the sliding process, and a tensioning process in which the tension of the rope is increased after the sliding process.

[0016] <11> A method for dismantling a large structure according to aspect 11 of the present invention is a method for dismantling a large structure according to any one of aspects 7 to 10, which includes, after the sliding step, a vertical member dismantling step of dismantling an upper part of the vertical member. Effect of the Invention

[0017] According to the present invention, it is possible to provide a net support device that is easy to handle and can accommodate large structures, and a method for dismantling a large structure using the net support device. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a side view showing a net support device installed on a structure. [Diagram 2] FIG. 2 is a plan view showing a net support device installed on a structure. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] 2 is a cross-sectional view taken along the line A in FIG. 1. [Figure 7] 2 is a cross-sectional view taken along the line B in FIG. 1. [Figure 8] This is an explanatory diagram showing a state in which a net covering the upper part of a structure to be demolished is stretched between multiple facing vertical members. [Figure 9] 13 is an explanatory diagram showing the sliding process and the replacement process for the other vertical material among a plurality of facing vertical materials. FIG. [Figure 10] 1 is an explanatory diagram showing a sliding process and a replacement process for one of a plurality of facing vertical members. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (Embodiment) Hereinafter, an embodiment of the present invention will be described. In the following description, the same numbers or symbols may be used to designate components having the same action or function. FIG. 1 is a side view showing a net support device 100 provided on a structure S (a large structure). FIG. 2 is a plan view showing the net support device 100 provided on the structure S. FIG. 3 is a plan view of a mounting bracket 20. FIG. 4 is a side view of a first member 30. FIG. 5 is a side view of a second member 40. FIG. 6 is a cross-sectional view taken along the line A in FIG. 1. FIG. 7 is a cross-sectional view taken along the line B in FIG. 1. Note that in FIG. 1, since the net support device 100 is symmetrical with respect to the structure S, one side centered on the structure S is shown as a representative, and the other side is not shown.

[0020] The structure S to be demolished is, for example, a building having multiple floors. When the structure S to be demolished is a building having multiple floors, the method of demolishing the building is usually to first demolish the top floor of the building, and then sequentially demolish the floors below it, one by one. Scaffolding (not shown) is erected from the ground surface so as to surround the structure S to be demolished. In this embodiment, the structure S is, for example, a large structure such as a high-rise building that is rectangular in plan view. In this embodiment, work related to the net support device 100 is performed, for example, with a worker standing on the above-mentioned scaffolding (not shown). When demolishing the structure S, a net 50 is installed on the top of the vertical members 10 to prevent objects that are likely to scatter during the demolition work from scattering outside, mainly from the top of the demolition site of the structure S.

[0021] (Net support device) As shown in FIG. 1, a net support device 100 according to this embodiment supports a net 50 that covers a structure S to be dismantled.

[0022] Here, as shown in Figures 1 to 7, the net support device 100 comprises a vertical member 10 installed around the structure S, a mounting bracket 20 that is removably attached to the vertical member 10, a first member 30 that extends along the longitudinal direction of the vertical member 10 and is removably attached to the vertical member 10 via the mounting bracket 20, and a second member 40 that extends along the first member 30, is engaged with the first member 30 so that its vertical position can be freely changed, and supports the net 50. In this way, the net support device 100 includes the first member 30 and the second member 40. Therefore, the net 50 can be moved (repositioned) downward with respect to the vertical member 10 in two stages: a stage of changing the vertical position by moving the second member 40 relative to the first member 30, and a stage of changing the vertical position by moving the first member 30 relative to the vertical member 10. Therefore, the vertical position of the net 50 can be changed by moving the second member 40 supporting the net 50 downward while the first member 30 is attached to the vertical member 10, so that the net 50 can be moved downward without removing the net 50, and the weight of the part that moves in one stage can be reduced. In addition, since the first member 30 is detachably attached to the vertical member 10 via the mounting bracket 20 in a state where it extends along the vertical member 10, the first member 30 can be moved a long distance in the vertical direction with a stable posture relative to the vertical member 10. Therefore, even without using a special lifting device, the net support device 100 can be easily handled and moved (relocated) in accordance with the downward progress of the dismantling work of the structure S. That is, for example, the first member 30 can be moved by human power. In addition, the net support device 100 can be made lightweight and have a compact cross-sectional dimension, so that it can be easily handled even in places where space is relatively limited, such as between a structure S and scaffolding (not shown).

[0023] (Vertical members) The vertical members 10 are long members that are installed around the structure S. The vertical members 10 are installed so that their longitudinal direction is along the vertical direction. The vertical members 10 are arranged between the structure S and a scaffolding (not shown). A plurality of the vertical members 10 are installed around the structure S at intervals. The intervals between the vertical members 10 are determined, for example, by the weight added to the vertical members 10 based on the type of net 50 and rope 60 used, the load added due to the slack of the rope 60, etc. In this embodiment, the intervals between the vertical members 10 are, for example, about 45 m, but may be set to any other interval. In detail, the vertical members 10 are arranged, for example, as follows. That is, for example, when the structure S is rectangular in plan view, the vertical members 10 are arranged so as to line up along the long sides of the structure S in plan view. At this time, the multiple vertical members 10 are arranged in pairs on the long sides of the structures S that face each other. That is, on the long sides of the structures S that face each other, each of the vertical members 10 arranged on one long side has a paired vertical member 10 at a corresponding position on the other long side. Hereinafter, the vertical members 10 are arranged so that each of the multiple vertical members 10 arranged on one long side of the structure S has a paired vertical member 10 on the other long side, which is simply referred to as the vertical members 10 being arranged in pairs. In this embodiment, as shown in Fig. 2, the vertical member 10 is an H-shaped steel having an H-shaped cross section formed by the web 11 and a pair of flanges 12. This provides the vertical member 10 with sufficient strength to effectively resist the bending moment acting on the vertical member 10 due to the weight of the net 50. Therefore, for example, the net support device 100 can be made compatible with a large structure S compared to a case in which the first member 30 and the second member 40 are attached to a work scaffold or the like. In this embodiment, the vertical member 10 has a plurality of vertical bolt holes 10h spaced apart in the longitudinal direction to which the mounting bracket 20 described below can be attached. This makes it possible to arbitrarily adjust the position of the mounting bracket 20 in the longitudinal direction of the vertical member 10. Furthermore, as long as it has the above-mentioned characteristics, the H-shaped steel used for the vertical members 10 at the construction site of the net support device 100 can be, for example, a rental product. By using known materials for the vertical members 10 in this way, for example, it is not necessary to use special materials, and costs can be reduced.

[0024] (Mounting bracket) The mounting bracket 20 is detachably attached to the vertical member 10. The mounting bracket 20 is used to attach a first member 30 to the vertical member 10. As shown in FIG. 2, the mounting bracket 20 can be attached to both the vertical member 10, which is an H-shaped steel as described above, and the first member 30. The position of the first member 30 relative to the mounting bracket 20 can be changed as appropriate according to conditions such as the positional relationship between the structure S and the vertical member 10. When the mounting bracket 20 is attached to the vertical member 10, which is an H-shaped steel, the mounting bracket 20 includes a first flange parallel portion 21 and a second flange parallel portion 22, each of which is parallel to the flange 12 of the vertical member 10, a web parallel portion 23 which is parallel to the web 11 of the vertical member 10, and a reinforcing portion 24 which connects the above-mentioned components together to reinforce the mounting bracket 20. The first flange parallel portion 21, the second flange parallel portion 22, the web parallel portion 23, and the reinforcing portion 24 are each a plate-shaped member. In this embodiment, the mounting bracket 20 is formed by welding these together. For this reason, as shown in FIG. 3, the mounting bracket 20 has a weld bead 25 formed at the welded portion.

[0025] As shown in FIG. 2 or FIG. 3, the first flange parallel portion 21 is located at the center of the web 11 of the vertical member 10 in the plate width direction and is arranged parallel to the pair of flanges 12. One end 21a of the first flange parallel portion 21 is located near the flange 12. As shown in FIG. 2 or FIG. 3, the other end 21b of the first flange parallel portion 21 protrudes in a direction away from the web 11 from the end 12e in the plate width direction of the flange 12 of the vertical member 10 when the mounting bracket 20 is attached to the vertical member 10. A first mounting bolt hole 20h1 is provided in a portion of the first flange parallel portion 21 protruding in a direction away from the web 11 from the end 12e in the plate width direction of the flange 12, through which the mounting portion 31 (described later) of the first member 30 can be inserted. In addition, a hanging hole 20h2 may be provided in a portion of the first flange parallel portion 21 located closer to the one end 21a than the center in the plate width direction. The hanging hole 20h2 is provided, for example, to pass a wire through when the mounting bracket 20 is lifted up with a wire or the like. Alternatively, the hanging hole 20h2 may be used as a handle. The hanging hole 20h2 may have a larger diameter than the first mounting bolt hole 20h1, for example. The web parallel portion 23 is connected to the center of the first flange parallel portion 21 in the plate width direction.

[0026] As shown in FIG. 2 or FIG. 3, the second flange parallel portion 22 is located near both ends of the web 11 of the vertical member 10 in the plate width direction and is arranged parallel to the pair of flanges 12. The second flange parallel portion 22 is provided in a pair corresponding to each of the pair of flanges 12. Each of the pair of second flange parallel portions 22 is fixed to the flange 12 by a bolt B. For this reason, each of the second flange parallel portions 22 has a second mounting bolt hole 20h3 at a position corresponding to the vertical bolt hole 10h of the vertical member 10. One end 22a of the second flange parallel portion 22 is located near the flange 12. At this time, it is preferable that one end 22a of the second flange parallel portion 22 is located at the same position as one end 21a of the first flange parallel portion 21 in the plate width direction of the flange 12. The other end 22b of the second flange parallel portion 22 is located near the end 12e of the flange 12 in the plate width direction. The other end 22b of the second flange parallel portion 22 is connected to the web parallel portion 23.

[0027] The web parallel portion 23 is disposed parallel to the web 11 as shown in FIG. 2 or FIG. 3. The web parallel portion 23 is provided in a pair on both sides of the first flange parallel portion 21 in the thickness direction. One end 23a of each of the pair of web parallel portions 23 is connected to the other end 22b of the second flange parallel portion 22. The other end 23b of each of the pair of web parallel portions 23 is connected to the center of the first flange parallel portion 21 in the width direction. In this case, it is preferable that the surface 23c of the web parallel portion 23 that does not face the web 11 is disposed so as not to be located farther from the web 11 than the end 12e of the flange 12 in the width direction in the flange 12 as shown in FIG. 2 or FIG. 3. Alternatively, the end 12e of the web parallel portion 23 in the thickness direction may be flush with the end 12e of the flange 12 in the width direction. Each of the pair of web parallel portions 23 is provided with a fourth mounting bolt hole 20h4 through which the mounting portion 31 of the first member 30 can be inserted.

[0028] 2 or 3, the reinforcing portion 24 reinforces the mounting bracket 20 by connecting the first flange parallel portion 21, the second flange parallel portion 22, and the web parallel portion 23. The reinforcing portion 24 is provided so as to be perpendicular to both the web 11 and the flange 12 of the vertical member 10. In other words, the plate thickness direction of the reinforcing portion 24 is aligned with the longitudinal direction of the vertical member 10. The mounting bracket 20 is configured with each of the above components. As shown in Fig. 2, the first member 30 can be attached to the mounting bracket 20 having the above configuration by inserting the mounting portion 31 of the first member 30 into either the first mounting bolt hole 20h1 or the fourth mounting bolt hole 20h4 and fixing with a nut N. The position of the first member 30 relative to the mounting bracket 20 may be changed as appropriate depending on conditions such as the positional relationship between the structure S and the vertical member 10. This makes it possible to more suitably position the first member 30 relative to the structure S and the vertical member 10.

[0029] (First member and second member) 1 and 4, the first member 30 is a rod-shaped body that extends along the longitudinal direction of the vertical member 10 that is installed around the structure S and is detachably attached to the vertical member 10 via a mounting bracket 20. Alternatively, the first member 30 may be attached directly to the vertical member 10 without using the mounting bracket 20. The first member 30 restricts the relative movement of the second member 40 in the horizontal direction. In detail, for example, as shown in FIG. 6 or FIG. 7, the first member 30 may be a groove-shaped member having a groove-shaped cross section of a substantially C-shape. This allows the second member 40 to move vertically relative to the first member 30 while restricting the horizontal movement of the second member 40, and allows the first member 30 and the second member 40 to move as a unit. In addition, the first member 30 restricting the relative movement of the second member 40 in the horizontal direction does not necessarily mean that the relative movement is completely restricted, but also means that the structural relationship between the first member 30 and the second member 40 allows a relative movement of a distance equivalent to a so-called play, for example, about 10 cm, but does not allow any more relative movement. In the present embodiment, a plurality of first members 30 are provided for one second member 40. That is, for example, two first members 30 are provided for one second member 40. Alternatively, without being limited thereto, three or more first members 30 may be provided for one second member 40. The first member 30 has a mounting portion 31 that is detachably attachable to the mounting bracket 20. The mounting portion 31 is a rod-shaped member that can be inserted into the first mounting bolt hole 20h1 or the fourth mounting bolt hole 20h4 that the mounting bracket 20 has. The base of the attachment portion 31 is attached to the outer peripheral surface of the first member 30 by welding or the like. This can prevent the attachment portion 31 from being positioned inside the groove-shaped cross section of the first member 30. This can prevent the attachment portion 31 from affecting the position and shape of the second member 40 positioned inside the groove-shaped cross section of the first member 30. Therefore, for example, the distance between the inner peripheral surface of the groove-shaped cross section of the first member 30 and the outer peripheral surface of the second member 40 can be made small. Also, for example, it is not necessary to provide an opening in the second member 40 to avoid the attachment portion 31, and the second member 40 can be a cylindrical member having a closed cross section. A threaded portion is provided at the tip of the mounting portion 31, and a nut N can be screwed into it. The first member 30 is fixed to the mounting bracket 20 by fastening the nut N with the mounting portion 31 inserted into the first mounting bolt hole 20h1 or the fourth mounting bolt hole 20h4 of the mounting bracket 20. In this way, the first member 30 is attached to the vertical member 10 via the mounting bracket 20. In this embodiment, two mounting portions 31 are provided in the longitudinal direction of the first member 30. As shown in FIG. 4, the mounting portions 31 are provided, for example, near both ends of the longitudinal direction of the first member 30, one each. In this way, the first member 30 is provided so as to be parallel to the vertical member 10. The first member 30 may be provided with a handle 32 for easy carrying. A latch 41 (described later) may be connected to the first member 30 by a chain (not shown) or the like to prevent loss.

[0030] As shown in FIG. 5, the second member 40 is a rod-shaped body extending along the first member 30. As shown in FIGS. 5 to 7, the second member 40 is a rectangular cylindrical member and has a so-called closed cross section that does not have an opening in cross section. This makes the second member 40 stronger than a member having an opening in cross section. Therefore, the second member 40 can effectively resist the bending moment acting on the second member 40 due to the weight of the net 50. This is particularly effective when, for example, the rope intermediate support part 44 of the second member 40 is located above the upper end of the first member 30. In cross section, the outer shape of the second member 40 is smaller than the inner shape of the first member 30 and has a dimension larger than the opening width of the first member 30, so that the second member 40 does not fall off the first member 30 when fitted in the first member 30.

[0031] The second member 40 is engaged with the first member 30 so that the vertical position can be changed. The second member 40 has a yoke 41. The yoke 41 is, for example, a round bar having a diameter of 9 mm. As shown in FIG. 6 or FIG. 7, the yoke 41 has a straight portion that penetrates through both the first member through hole 30h provided in the first member 30 and the second member through hole 40h provided in the second member 40 so as to be freely insertable and removable. This allows the second member 40 to be engaged with the first member 30 and to be freely slidable. In addition, the yoke 41 may have a bendable tip after being inserted into the first member through hole 30h and the second member through hole 40h in order to prevent the yoke 41 from unintentionally falling out from the state in which it is inserted into the first member through hole 30h and the second member through hole 40h. In order to facilitate sliding of the second member 40 relative to the first member 30, the second member 40 may be provided with a slide plate 42 on its outer circumferential surface as shown in FIG. 5. The slide plate 42 is made of, for example, a plate material such as SS400. The slide plate 42 is welded to the outer circumferential surface of the second member 40. At this time, it is preferable that the corners of the slide plate 42 are appropriately chamfered. This preferably prevents the corners of the slide plate 42 from getting caught on the inner circumferential surface of the first member 30 when the second member 40 is slid relative to the first member 30. The second member 40 supports the net 50 .

[0032] In detail, the second member 40 is restricted from relative movement in the horizontal direction by the first member 30. The second member 40 may be fitted inside the groove-shaped cross section of the first member 30, for example, as shown in Figs. 6 and 7. This allows the second member 40 to be moved vertically while keeping its longitudinal direction aligned with the vertical direction, using the first member 30 as a guide. Therefore, the second member 40, which is holding the net 50, can be moved downward in a stable vertical position. Furthermore, the structural relationship between the first member 30 and the second member 40 is not limited to one in which one has a groove-shaped cross-section and the other has a cross-section that fits inside the groove-shaped cross-section, as long as they regulate relative movement in the horizontal direction.

[0033] (net) The net 50 is for capturing objects scattered from the structure S to be demolished without letting them through. The net 50 is a planar net having mesh that is not subject to excessive wind pressure and does not let scattered objects through. The net 50 may be supported on the upper part of the vertical member 10 via the net support device 100 with its surface aligned vertically. The net 50 may be supported by a rope 60 stretched between a pair of opposing vertical members 10 arranged on the sides of the structure S, with the net 50 in a horizontal position via the net support device 100.

[0034] The net 50 may include a rope 60 and a net portion 70 supported by the rope 60. The second member 40 may have a rope tension support portion 43 that supports the tension of the rope 60, and a rope middle support portion 44 that slidably supports the middle of the rope 60. This allows the second member 40 to support the weight of the net portion 70 of the net 50 via the rope 60. In this embodiment, for example, a known general eye bolt is preferably used for the rope tension support part 43, as shown in Fig. 7. For example, a rotatable eye bolt is preferably used for the rope intermediate support part 44, as shown in Fig. 6. Specifically, for example, a double swivel ring (registered trademark) is preferably used for the rope intermediate support part 44.

[0035] (Tension adjustment device) 1, the lifting machine may include a tension adjusting device 80 that connects the end 60e of the rope 60 to the rope tension support part 43 and can change the distance between the end 60e of the rope 60 and the rope tension support part 43. The tension adjusting device 80 may be a lifting machine having a first hook 81 that can be hooked to the rope tension support part 43, a second hook 82 that can be hooked to the end 60e of the rope 60, a cord-like body 83 such as a chain that connects between the first hook 81 and the second hook 82, and a lever 84 that can adjust the length of the cord-like body 83 between the first hook 81 and the second hook 82.

[0036] (Disassembly method) Next, a method for dismantling the structure S using the above-mentioned net support device 100 will be described with reference to Figs. Fig. 8 is an explanatory diagram showing a state in which a net 50 covering the upper part of a structure S to be demolished is stretched between multiple vertical members 10. Fig. 9 is an explanatory diagram showing a sliding process and a replacement process for another vertical member 10 of the multiple vertical members 10. Fig. 10 is an explanatory diagram showing a sliding process and a replacement process for one vertical member 10 of the multiple vertical members 10.

[0037] (S1) First, as shown in FIG. 8, a pair of vertical members 10 are installed so as to face each other with a structure S in between (vertical member installation step).

[0038] (S2) Next, each component of the net support device 100, except for the vertical members 10, is attached to each of the pair of vertical members 10 (net support device attachment process). In detail, as shown in Fig. 1, with the mounting brackets 20 attached to the vertical members 10 in advance, the mounting parts 31 provided on the first member 30 are attached to the vertical members 10 via the mounting brackets 20 as described above.

[0039] (S2-1) Here, as shown in Fig. 1, the first member 30 may include an upper first member 30U and a lower first member 30B that is disposed below the upper first member 30U along the axis of the upper first member 30U. In this case, in the net support device mounting step, the upper first member 30U and the lower first member 30B are mounted to the vertical member 10 (split installation step).

[0040] (S3) Next, as shown in Fig. 8, a rope 60 is stretched between the pair of vertical members 10 via the second member 40 (rope tensioning process). In detail, the end 60e of the rope 60 is pulled using a tension adjustment device 80 that receives a reaction force from the rope tension support part 43 of the second member 40. This allows the net 50 to cover the top of the structure S to be demolished.

[0041] (S4) If necessary, dismantle the upper part of the structure S (structure dismantling process).

[0042] (S5) Here, as appropriate, the tension of the rope 60 is reduced (relaxation step) before the next sliding step, as shown in Fig. 9. This reduces the frictional force between the first member 30 and the second member 40, making it easier for the second member 40 to slide.

[0043] (S6) Next, as shown in Fig. 9, of the pair of vertical members 10, the second member 40 arranged on the other vertical member 10 is slid downward, for example, by about 3.4 m relative to the first member 30 (sliding process). Then, the net 50 supported by the second member 40 moves downward.

[0044] (S6-1) After this, as shown by the dashed arrow in FIG. 9, the first member 30 and the mounting bracket 20 are removed from the vertical member 10, moved downward, for example, by about 4 to 6 m, and attached to the vertical member 10 (replacement process). At this time, it is also possible to remove only the first member 30 and the mounting bracket 20 from the vertical member 10 and move them downward while maintaining the height position of the second member 40 by supporting the second member 40 on the vertical member 10, as appropriate. In this case, it is preferable to remove only the topmost one of the multiple first members 30 supporting one second member 40 (in this embodiment, the upper first member 30U) and move it directly below the bottommost one of the multiple first members 30 (in this embodiment, the lower first member 30B). It is preferable to repeat this process so that the multiple first members 30 can support the second member 40 again when the second member 40 is moved downward. Alternatively, without being limited to this, the first member 30 and the mounting bracket 20 together with the second member 40 may be removed from the vertical member 10, and both the first member 30 and the mounting bracket 20 and the second member 40 may be moved downward.

[0045] (S6-2) In the net support device installation process, when the upper first member 30U and the lower first member 30B are attached to the vertical member 10 (after the division installation process), in the sliding process, as shown by the downward white arrow in Fig. 1, the second member 40 is slid downward from the upper first member 30U until it fits into the lower first member 30B, and then the second member 40 is locked to the lower first member 30B (locking process). In detail, the latch 41 penetrating the second member 40 and the upper first member 30U is temporarily removed, the second member 40 is slid from the upper first member 30U to fit into the lower first member 30B, and then the latch 41 is penetrating the second member 40 and the lower first member 30B and locked.

[0046] (S7) Next, the uppermost first member 30 (upper first member 30U) and the mounting bracket 20 corresponding to that first member 30 are removed from the vertical member 10.

[0047] (S8) Next, after the above-mentioned sliding process, the upper part of the vertical member 10 is dismantled (vertical member dismantling process).

[0048] (S9) Next, especially when the relaxation process for reducing the tension of the rope 60 has been performed, the tension of the rope 60 is increased (tensioning process) after the above-mentioned sliding process. Note that the method for increasing the tension of the rope 60 may be a method of pulling the rope 60 using the tension adjusting device 80, as in the above-mentioned rope tensioning process.

[0049] (S10) Next, as shown in Fig. 10, the above-mentioned structure dismantling process, sliding process and vertical member dismantling process are performed on one of the pair of vertical members 10 in the same manner as the other vertical member 10. Then, by repeating this process alternately in sequence on both of the pair of vertical members 10, the net support device 100 supporting the net 50 is moved downward in synchronization with the sequential dismantling of the structure S from the top downward, and the vertical members 10 are dismantled.

[0050] In this way, according to the method for dismantling a structure S using the net support device 100 of this embodiment, the second member 40, which is a part of the member constituting the net support device 100, can be slid downward and moved while supporting the net 50 without removing the net 50. In addition, since the vertical member 10 is an H-shaped steel and has sufficient strength, it can effectively resist the bending moment acting on the vertical member 10 due to the weight of the net 50, compared to when the first member 30 and the second member 40 are attached to a work scaffold or the like. Therefore, the net 50 can be easily and stably moved downward according to the progress of the dismantling of the structure S without using a special lifting device. Therefore, it is possible to provide a method for dismantling a structure S using the net support device 100 that is easy to handle and can handle large structures S. Furthermore, when the first member 30 and the second member 40 are attached to the work scaffold, the work scaffold cannot be dismantled unless the first member 30 is removed from the work scaffold. As in the present embodiment, by attaching the first member 30 to the vertical member 10, the work scaffolding can be dismantled without involving the first member 30. Therefore, the dismantling process of the work scaffolding can be adjusted more flexibly. According to the method for demolishing a structure S using the net support device 100, for example, in a demolition work cycle in which a structure S such as a multi-story building is demolished from the upper floors to the lower floors using heavy machinery, the work of replacing the net 50 downward can be performed independently with a relatively simple device without using the heavy machinery, so that the work of replacing the net 50 is not a critical path in the entire process of the demolition work of the structure S, and the heavy machinery can be used continuously by being dedicated to the demolition work, and can be always positioned downward according to the progress of the demolition work. This improves the efficiency of use of the heavy machinery, contributes to shortening the overall construction period of the demolition work, and allows the structure S to be demolished safely and economically. Here, when dismantling the structure S, there is a strength limit to the height (vertical length) at which the scaffolding (not shown) provided around the structure S can remain above the upper end of the wall of the structure S and stand on its own. For this reason, for example, when the first member 30 and the second member 40 are attached to a work scaffolding or the like, in order to keep the position of the net 50 above the structure S, it may be necessary to dismantle the floor part first, leaving the wall part of the structure S that supports the scaffolding via the wall ties. In contrast, according to the method for dismantling a structure S using the net support device 100 of this embodiment, since the vertical members 10 are H-shaped steel and have sufficient strength, it is not necessary to consider the impact on the dismantling procedure of the structure S, and the timing of dismantling the wall parts of the structure S can be accelerated. Therefore, the vertical length from the heavy equipment placed on the floor part of the structure S being dismantled to the net 50 hooked to the upper part of the vertical members 10 can be secured relatively long, ensuring sufficient working space for the heavy equipment, and making it possible to smoothly carry out the dismantling work of the structure S.

[0051] (Other embodiments) Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications and the like are possible.

[0052] The net support device 100 of this embodiment supports a net 50 covering a structure S to be dismantled. The net support device 100 includes a first member 30 that extends along a vertical member 10 installed around the structure S and is detachably attached to the vertical member 10 via a mounting bracket 20, and a second member 40 that extends along the first member 30 and is engaged so that its vertical position can be freely changed relative to the first member 30 and supports the net 50. This allows the net 50 to be moved (repositioned) downward relative to the vertical member 10 in two stages: a stage in which the second member 40 is moved relative to the first member 30 to change the vertical position, and a stage in which the first member 30 is moved relative to the vertical member 10 to change the vertical position. Therefore, the vertical position of the net 50 can be changed by moving the second member 40 supporting the net 50 downward while the first member 30 is attached to the vertical member 10, so that the net 50 can be moved downward without removing the net 50, and the weight of the part that is moved in one stage can be reduced. In addition, since the first member 30 is detachably attached to the vertical member 10 via the mounting brackets 20 while extending along the vertical member 10, the first member 30 can be moved a long distance in the vertical direction in a stable posture relative to the vertical member 10. Therefore, the net support device 100 can be easily handled and relocated (rearranged) according to the downward progress of the dismantling work of the structure S, without using a special lifting device.

[0053] The method for dismantling the structure S using the net support device 100 of this embodiment includes a vertical member installation step of installing a pair of vertical members 10 so as to face each other across the structure S, a net support device installation step of attaching each component of the net support device 100, except for the vertical members 10, to each of the pair of vertical members 10, and a sliding step of sliding the second member 40 downward relative to the first member 30. This allows the second member 40, which is a part of the net support device 100, to be slid downward and moved while supporting the net 50 without removing the net 50. In addition, since the vertical member 10 is an H-shaped steel and has sufficient strength, it can effectively resist the bending moment acting on the vertical member 10 due to the weight of the net 50, compared to when the first member 30 and the second member 40 are attached to a work scaffold or the like. Therefore, the net 50 can be easily and stably moved downward according to the progress of the dismantling of the structure S without using a special lifting device. Therefore, a method for dismantling a structure S using the net support device 100 can be provided, which is easy to handle and can accommodate large-sized structures S.

[0054] In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0055] 10 Vertical members 10h Vertical bolt hole 11. Web 12 Flange 20 Mounting bracket 20h1 First mounting bolt hole 20h2 Hanging hole 20h3 Second mounting bolt hole 21 First flange parallel section 22 Second flange parallel section 23 Parallel web section 24 Reinforcement 25 Weld Bead 30 First member 30B Lower first member 30h First component through hole 30U Upper 1st member 31 Mounting part 40 Second member 40h Second component through hole 41 Lock 42 Slide plate 43 Rope tension support 44 Rope intermediate support 50 Net 60 Rope 70 Amibe 80 Tension adjustment device 81 First Hook 82 2nd Hook 83 Funicular body 84 Lever 100 Net support device B Bolt N Nut S structure

Claims

1. A net support device for supporting a net covering a large structure to be demolished, A plurality of vertical members are installed around the large structure; A first member extending along a longitudinal direction of the vertical member and removably attached to the vertical member; A second member that extends along the first member, is engaged with the first member so as to be freely changeable in vertical position, and supports the net; Equipped with The vertical member is an H-shaped steel having an H-shaped cross section formed by a web and a pair of flanges, The mounting bracket further includes a first flange parallel portion and a second flange parallel portion, each of which is parallel to the flange of the vertical member, and a web parallel portion of the vertical member, the web being parallel to the web of the vertical member; The first member is attached to the vertical member via the mounting bracket, The position of the first member relative to the mounting bracket is variable. Net support device.

2. The net includes a rope and a net portion supported by the rope, The second member has a rope tension support part that supports the tension of the rope and a rope intermediate support part that slidably supports the intermediate part of the rope, A tension adjusting device is provided which connects the end of the rope and the rope tension support part and can change the distance between the end of the rope and the rope tension support part.

2. The net support device of claim 1.

3. 2. The net support device according to claim 1, wherein the first member is a channel-shaped member having a generally C-shaped channel-shaped cross section, and the second member is a tubular member having a closed cross section.

4. The mounting bracket is detachably attached to the vertical member. A net support device according to any one of claims 1 to 3.

5. A method for dismantling the large structure using the net support device, comprising: A vertical member installation process of installing a pair of the vertical members so as to face each other across the large structure; A net support device installation process in which each component of the net support device, except for the vertical members, is attached to each of a pair of the vertical members; The method for dismantling the large structure using the net support device according to claim 4, further comprising a sliding step of sliding the second member downward relative to the first member.

6. A transfer process in which the first member and the mounting bracket are removed from the vertical member, moved downward, and attached to the vertical member. A method for dismantling a large structure using the net support device according to claim 5.

7. The first member includes an upper first member and a lower first member disposed below the upper first member along an axis of the upper first member, The net support device mounting step includes a division installation step of mounting the upper first member and the lower first member to the vertical member, the sliding step includes a locking step of sliding the second member downward from the upper first member until the second member fits into the lower first member, and then locking the second member to the lower first member. A method for dismantling a large structure using the net support device according to claim 5.

8. A rope stretching process of stretching a rope between the pair of vertical members via the second member; a relaxation step of reducing tension on the rope before the sliding step; The method for dismantling a large structure using the net support device according to claim 5, further comprising a tensioning step of increasing tension of the rope after the sliding step.

9. The method for dismantling the large structure using the net support device as described in claim 5, further comprising a vertical member dismantling step of dismantling the upper part of the vertical member after the sliding step.

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