JP2005207101A - Method of demolition of structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of demolition of a structure for reducing a work period and the cost, improving safety by shortening the work period at a high place, and substantially reducing the shock and vibrations given to the ground caused by the demolition of the structure. <P>SOLUTION: A V-shaped blasting cable is set along blast-cut lines S, S positioned at both ends of a girder 2. The blast-cut lines S, S are formed to have a truncated chevron shape when viewed from the side so that the girder may fall easily. A shock absorbing mound 5 is arranged on the ground to absorb the shock caused by the fall of the girder 2 and a toppling of a hinged leg 3 and a fixed leg 4. After finishing preparation work for the blast, the blast is carried out along the blast-cut lines S, S and the girder 2 is cut to allow the girder 2 to fall freely. The hinged leg 3 and the fixed leg 4 topple freely having their foot parts as centers of rotation, respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure demolition method, and particularly to a low-rise structure demolition method.

Conventionally, the structure is dismantled by sequentially cutting individual structural members by gas cutting or a hydraulic crusher. However, several methods for dismantling structures using explosives have been proposed from the viewpoint of improving safety by reducing the construction period and cost, or by reducing the working period at high places. For example, Patent Document 1 discloses a method of dismantling the steel tower after blasting and cutting the lower part of the steel tower pillar to invert the steel tower. Moreover, in patent document 2, after providing a hollow part in a pillar member, one of the vertical parts on both sides of the hollow part is blasted and crushed to generate an unbalanced moment, thereby forming a collapse mechanism in the entire structure. Demolition method is shown.
JP 2003-184344 A (page 2-3, FIG. 5) JP-A-6-346610 (page 2-3, FIG. 2)

However, in the case of the dismantling method using blasting described in Patent Document 1, Patent Document 2, and the like, the impact on the ground, vibration, and dust due to overturning or crushing of the structure is enormous. In addition, in the case of the dismantling method described in Patent Document 2, the provision of the hollow portion in the column member itself is a work that consumes a work period and a work cost, and there is a possibility that the merit by blasting may be lost.
The present invention has been made in view of the above-mentioned problems, and it is possible to improve the safety by reducing the work period and cost, and by reducing the work period at high places, and the impact on the ground accompanying the dismantling of the structure, An object of the present invention is to provide a structure dismantling method that can greatly reduce vibration.

In order to achieve the above object, the structure demolition method according to the present invention is a structure demolition method consisting of a column and a beam, and both ends of the beam are simultaneously blasted and cut to drop an intermediate portion of the beam. Then, the column having the end portion of the beam at the top is allowed to fall freely.
At this time, it is preferable to control the fall direction of the column and the time required for the fall by adjusting the position at which the beam is blasted and cut.
In the present invention, since both ends of the beam are simultaneously blasted and cut to drop the beam, the column is freely toppled, so that there is a time difference between the time required for the beam to fall and the time required for the column to fall. As a result, the impact and vibration generated in the ground can be dispersed and reduced.

Moreover, in the structure demolition method according to the present invention, a notch portion may be formed in the leg portion of the column.
In the present invention, by forming a notch portion in advance in the leg portion of the column, the column can be easily tumbled freely.

In the structure demolition method according to the present invention, it is preferable to dispose an impact absorber on the ground.
Here, the impact absorber absorbs impact energy by changing its shape, for example, an impact absorption mound formed in a truncated cone shape using sand or clay, synthetic rubber, etc. Anti-vibration material mainly composed of the elastic body.
In the present invention, the impact energy generated by the fall of the beam and the fall of the column is absorbed by the impact absorber, whereby the impact and vibration generated in the ground can be further reduced.

  According to the present invention, both ends of the beam are simultaneously blasted and cut to drop the beam, and then the column is freely toppled. Therefore, the work period and work cost can be reduced, and the safety can be improved by reducing the work period at high places. . In addition, according to the present invention, there is a time difference between the time required for the beam to fall and the time required for the column to fall, so that it is possible to greatly reduce the impact and vibration on the ground due to the dismantling of the structure. it can.

Hereinafter, an embodiment of a structure demolition method according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a blast cutting location in a first embodiment of a structure demolition method according to the present invention. FIG. 2 is a schematic view showing the work process of the first embodiment of the structure demolition method according to the present invention.
As shown in FIG. 1, in the first embodiment, the present invention is applied to dismantling a steel portal crane 1.
The portal crane 1 includes a girder 2, a swing leg 3 that pin-supports one end of the girder 2, a rigid leg 4 that rigidly supports the other end of the girder 2, and a trolley 6 that moves on the girder 2. . The legs of the swing leg 3 and the rigid leg 4 are provided with wheels, respectively, so that they can move on the track in the out-of-plane direction of FIG.

  First, an explosive called a V-shaped shaped explosion broken line 11 is set along the blast cutting lines S and S at both ends of the girder 2. At this time, the blast cutting lines S and S at both ends of the girder 2 are formed in a C shape in a side view so that the girder 2 is easily dropped. Further, since the center of gravity of the swinging leg 3 and the leg part of the swinging leg 3 are on the same vertical plane, it is necessary to move the center of gravity of the swinging leg 3 toward the rigid leg 4 so that the swinging leg 3 can easily fall over. is there. Therefore, the blast cutting line S on the swing leg 3 side of the girder 2 is moved to the rigid leg 4 side. Further, by doing so, the swinging leg 3 becomes more to the top than the rigid leg 4, so that the swinging leg 3 falls freely more quickly than the rigid leg 4.

  A V-shaped explosive broken line 11 is a special explosive for cutting metal, in which a metal sheath 11a made of copper or lead is filled with a high-performance explosive 11b and the cross section is formed in an inverted V shape (see FIG. 3). When detonation occurs, the inverted V-shaped part becomes a high-temperature, high-pressure, high-speed jet, and instantaneously cuts the metal. At this time, there is no scattering of lead metal pieces to the peripheral part, and the blast jet part is vaporized due to high temperature and high pressure after the metal is cut.

  An impact absorbing mound 5 is disposed on the ground in order to reduce the impact caused by the fall of the girder 2 and the falling of the swing leg 3 and the rigid leg 4. The shock absorbing mound 5 is formed in a truncated cone shape using sand or clay.

When the preparatory work for blasting is completed, the worker is evacuated to confirm safety, and then blasts along the blast cutting lines S, S to cut the girder 2 (see FIG. 2A). At this time, it is necessary to cause blasting simultaneously at the blast cutting lines S and S at both ends of the girder 2.
When the girder 2 is cut, as shown in FIG. 2 (b), the girder 2 immediately starts free fall and reaches the ground in a short time.
On the other hand, as shown in FIGS. 2C and 2D, the swing leg 3 and the rigid leg 4 naturally fall over with the leg portion as the center of rotation.

In the structure demolition method according to this embodiment, both ends of the girder 2 are simultaneously blasted and cut to drop the girder 2, and then the rocker leg 3 and the rigid leg 4 are allowed to fall freely. And a time difference between the swing leg 3 and the time required for the rigid leg 4 to fall. As a result, the impact and vibration generated in the ground can be dispersed and reduced.
Further, in the structure demolition method according to the present embodiment, the shock absorbing mound 5 absorbs the impact energy caused by the fall of the girder 2 and the fall of the swing leg 3 and the rigid leg 4 to further reduce the shock and vibration generated in the ground. I am letting.

FIG. 4 is a schematic diagram showing work steps in the second embodiment of the structure demolition method according to the present invention.
As shown in FIG. 4, in the second embodiment, the present invention is applied to the dismantling of the one-layer multi-span structure 20.
First, as shown in FIG. 4A, the beam 21 is cut by blasting along the blast cutting lines S ₁ and S ₁ at both ends of the beam 21. When the beam 21 is cut, the beam 21 immediately starts free fall and reaches the ground in a short time. On the other hand, the pillar 23 falls freely with the leg portion of the pillar 23 as a rotation center.
Next, as shown in FIG. 4C, the beam 22 is cut by blasting along blast cutting lines S ₂ and S ₂ at both ends of the beam 22. When the beam 22 is cut, the beam 22 falls freely, and the column 24 falls freely about the column 24 leg.
Thereafter, the same operation is repeated, and finally the one-layer multi-span structure 20 is disassembled.

  In addition, you may form the notch part in the leg part of the pillars 23 and 24 previously using a breaker, a cutter, etc. so that the pillars 23 and 24 may fall over freely.

  In the dismantling method of the structure according to the present embodiment, the beams 21 and 22 and the columns 23 and 24 of the one-layer multi-span structure 20 are separated from one side by sequentially blasting and cutting both end portions of the beams 21 and 22 that are continuously provided. It will be dismantled sequentially. Therefore, a large impact and vibration do not occur on the ground.

  As mentioned above, although embodiment of the structure demolition construction method concerning this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably. For example, in the above embodiment, a single-layer structure is targeted, but the present invention can also be applied to a multilayer structure having two to several layers.

It is the schematic which shows the blast cutting location in 1st embodiment of the structure demolition construction method which concerns on this invention. It is the schematic which shows the operation process of 1st embodiment of the structure demolition construction method which concerns on this invention. (A) is a perspective view of a V-shaped forming explosion broken line, and (b) is a sectional view thereof. It is the schematic which shows the operation | work process in 2nd embodiment of the structure demolition construction method which concerns on this invention.

Explanation of symbols

1 portal crane 2 girder 3 Yuraashi 4 Tsuyoshiashi 5 shock absorbing mound 6 trolley 11 V molding blow line 20 1-layer multi-span structures 21, 22 the beams 23 and 24 poster _S, S 1, _{S 2} blasting cut part

Claims (4)

A method of dismantling a structure consisting of columns and beams,
A structure dismantling method characterized in that both ends of the beam are simultaneously blasted and cut to drop an intermediate portion of the beam, and then the column having the end of the beam at the top is freely overturned.   The method for disassembling a structure according to claim 1, wherein the falling direction of the column and the time required for the falling are controlled by adjusting the position at which the beam is blasted and cut.   The method for disassembling a structure according to claim 1 or 2, wherein a notch is formed in a leg portion of the column.   4. The method for demolishing a structure according to claim 1, wherein an impact absorber is disposed on the ground.

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