JP2003184344A - Iron tower demolishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an iron tower demolishing method which implements demolition of an iron tower safely and in a short period of time. <P>SOLUTION: According to the method, a lower portion of an iron tower support 1a on a tower toppling side is connected to a lower portion of an iron tower support 1b on the side opposite to the tower toppling side, by means of a cable 10, and then prestress is introduced to the cable 10. Thereafter, three portions of the lower portion of each iron tower support 1a, which are aligned in the height direction, are blasted and cut, to thereby topple the iron tower T. After the toppling, the iron tower T is demolished. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dismantling a steel tower, and more particularly to a method for dismantling a steel tower which is characterized by a method of turning over a steel tower for dismantling. 2. Description of the Related Art The dismantling work of a steel tower is disclosed in JP-A-2001-15.
This is performed by a method as described in Japanese Patent No. 9249, for example, using a large crane or the like as shown in FIG. That is, a large tower crane 50 is installed along the tower T, and is sequentially cut into blocks of a predetermined height unit from the top side of the tower T and suspended on the ground.
This is done by dismantling each block suspended on the ground. In FIG. 13, reference numeral 51 denotes a horizontal stay of a tower crane, and reference numeral 52 denotes a crawler crane for small-payment handling. [0003] In order to dismantle a steel tower, assembling and dismantling work of a large tower crane and the like are required. However, the work is a high-place work, and sufficient measures for safety are required. You. In addition, the work of assembling and disassembling the above-mentioned crane and the like may be a factor of elongating the construction period or increasing the cost. Further, since the work of cutting and suspending a steel tower using an assembled large crane or the like is a work in which heavy objects are handled at a high place, sufficient consideration for safety is required in the cutting and hanging work. Need to be applied. In addition, since the work is performed at a high place, the work is easily affected by the weather and the like, and this also causes an increase in the construction period and cost. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a dismantling method capable of safely disassembling a steel tower in a short period of time in dismantling work of the steel tower. [0005] In order to solve the above-mentioned problems, the present invention relates to a method for dismantling a steel tower in which a steel tower is overturned and then dismantled. Blast the lower part of each tower support to be blasted at three or more places separated from each other in the height direction, and connect a cable between the lower part of the tower to be blasted and the tower support not to be blasted before the blast cut. It is characterized in that the cable is connected and a tensile force is introduced into the cable. According to the present invention, the lower part of the tower on the tipping side is blasted and cut, and the pieces generated by the blasting and cutting can be surely displaced from the axis of the tower support, so that the tower can be reliably tilted in the planned direction. Can be. By dismantling the tower, the dismantling of the tower becomes a work on the ground. An embodiment according to the present invention will be described below with reference to the drawings. In the present embodiment, FIG.
The disassembly of a tower T having four tower columns 1 as shown in FIG. The reference numeral 2 indicates the elevator shaft 2, but may be a chimney or the like. In the present embodiment, the legs of the elevator shaft 2 are gas-cut after being supported by temporary supporting columns made of H-shaped steel or the like. First, a direction in which the tower T is to be turned over is determined.
The two tower columns 1 on the side to be overturned are assumed to be a tower column 1a to be blasted and cut. In the present embodiment, a case where the steel tower T is set to be overturned on the right side is exemplified. A main pole blasting cut-off location S and an elevator shaft temporary receiving support blasting blasting cut-off location K are respectively set below the two tower stanchions 1a to be blasted and cut. The blast cutting locations S to be set on each of the tower supports 1a are set at three locations at predetermined intervals in the height direction. By setting three blasting cuts S in the height direction, the portion sandwiched between the upper and lower blasting cuts S becomes two cutting pieces 3, and the number of the cutting pieces 3 becomes two.
The cutting piece 3 is surely shifted away from the axis of each strut 1a (extending direction of the strut), and as shown in FIG. When the blast cut portion of the steel tower T descends and lands, the axis of the tower T tilts to the right. Subsequently, as the center of gravity of the tower T moves to the right, the leg of the left column 1b rises as shown in FIG. 3, and the tower T tilts to the right, and as shown in FIG. To fall. Reference numeral 4 in FIG. 4 denotes an embankment for reducing ground vibration when the overturned tower T lands. Next, the tower T is dismantled on the ground.
By disassembling the tower T after it is turned over, the tower T can be dismantled on a stable ground. Here, temporarily
If the blast cut piece 3 does not come off, the steel tower T
Is in an unstable state, for example, a situation in which the falling direction is unstable. However, in this embodiment, each strut 1 to be blasted and cut is used.
The cutting pieces 3 that are separated from the main body 1a of the column 1a by the cutting are cut out by blasting and cutting at three places for each of the two pieces.
It becomes a book and each cutting piece 3 located between the cuttings
It is easy to deviate from the axis a. In addition, one tower support 1a
In the case where only two cutting portions are used, since there is only one cutting piece 3 from which the cutting portion should be removed, there is a possibility that the cutting piece 3 is less likely to come off the axis of the column 1a. In this respect, in the present invention, by separating the cutting piece 3 into two or more cutting pieces 3, the cutting piece 3 is easily separated from the axis of the column 1a, and the tower T can be turned over in the planned turning direction. Further, at least one of the three blasting cuts set on each column 1a has a cut surface at a cutting position,
As shown in FIG. 5, when the cutting line is set to be inclined in a side view so that there is a predetermined angle between the column 1a and the plane perpendicular to the axis of the column 1a, the cutting piece 3 It becomes easy to be displaced from the axis, and the cutting piece 3 is detached more reliably, so that the steel tower T is easily turned over in the planned direction. Reference numeral 10 denotes a cable described later. Reference numeral 11 denotes a temporary support column for receiving the elevator shaft 2. In the present embodiment, the diagonal material indicated by reference numeral 8 is cut and removed in advance. In this embodiment, in order to reduce the amount of explosive used for blast cutting, about 50% of the main column cutting line in the circumferential direction is gas cut. That is, as shown in FIGS. 6 and 7, at each cutting position, a cutting line C is set in a direction inclined in the circumferential direction, and gas is cut in advance at two axially symmetric locations C1. C2 is a position to be cut by blasting. Reference numeral 12 denotes an opening formed by gas cutting. Further, the explosive 13 is set along the remaining cutting position to perform the blast cutting. Reference numeral 14 denotes an electric detonator. By doing so, not only the amount of the explosive 13 can be reduced as described above, but also the blast noise can be reduced. Further, in the present embodiment, a cable tensioning method using a cable 10 made of a PC steel wire is applied so that the cutting piece 3 by the blast cutting is more reliably pulled out. More specifically, before blasting and cutting, as shown in FIGS. 8 and 9, one of the cutting pieces 3 separated by blasting and cutting and the lower part of the tower column 1 not to be blasted and cut are connected to the cable 1 as shown in FIG.
In addition to the connection at 0, a predetermined prestress is introduced to the cable 10 by the jack 15. The jack 15 is removed after a predetermined prestress is introduced into the cable. As described above, by introducing a force for pulling the inside of the tower T by the cable 10 into the cutting piece 3 before the blast cutting, the cutting piece cut at the same time as the blast cutting as shown in FIG. The cutting piece 3 is drawn into the steel tower T, and the cut piece 3 after cutting can be more reliably removed from the axis of the column 1a. In addition, by using the jack 15, a predetermined prestress can be surely introduced into the cable 10 in a short time with a simple device. [0015] Here, as shown in FIG.
A method of introducing a pulling force into the cable 10 by attaching a pulley to the side and suspending the weight 20 via the pulley 19 is also conceivable. However, a concrete block or a steel lump is assumed as the weight 20, and a considerable amount of time and cost are required to procure and suspend materials. In this regard, it is more advantageous to connect the columns 1 with the cable 10 and apply prestress to the cable 10 with the jack 15, because the work for tensioning the cable becomes easier and the cost is reduced. A method of pre-processing the legs of the tower support 1a on the opposite side of the tower from overturning will be described with reference to FIG. 12 before the processing. As described above, it is necessary to smoothly lift the leg portion of the column 1b on the opposite side of the tower from overturning during the tower overturning process. For this reason, the concrete 22 on the base plate 21 above the leg of the column 1b is removed and the anchor bolt 23 is gas-cut in advance so as not to stop the overturning movement. That is, the concrete portion described as the anchor removal range portion in FIG. 12 is peeled off, and the exposed anchor portion is removed. It is not necessary to remove the anchor bolts from the tower support 1a on the falling side in advance. As described above, in the present embodiment, the tower column 1a on the falling side is blasted and cut at three places in the height direction, and at least one cross section of the three places is inclined by cutting the cut surface, thereby separating the tower support 1a by blasting and cutting. It is possible to reliably pull out the cut piece 3 thus obtained. A cable 10 made of PC steel wire is connected between the cutting piece 3 of the column 1a to be cut by blasting and the lower end of the steel tower column 1b on the side opposite to the falling direction, and a prestress is applied to the cable 10. With the introduction, the cutting piece 3 of the post 1a after the blasting and cutting can be reliably pulled out, and the steel tower T can be surely turned over in the planned direction. Further, by removing the holding concrete and the anchor bolt of the leg of the column 1b on the side opposite to the fall,
Suppressing the overturning movement of the tower T is also reliably prevented. Since the tower T is turned over by blasting and cutting, it is possible to reduce work at high places and shorten the construction period.
In the above description, a steel tower having four pillars is illustrated, but three or five or more pillars may be used. As described above, when the present invention is employed, assembling and dismantling of a large crane and the like are not required, work at a high place is greatly reduced, and dismantling of a steel tower is performed on the ground. As a result, not only the safety of the work is improved, but also the work period of the dismantling work can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a steel tower according to an embodiment based on the present invention, wherein (a) is a side view and (b) is a plan view showing the arrangement of columns. FIG. 2 is a diagram illustrating a behavior after blast cutting according to the embodiment according to the present invention. FIG. 3 is a view showing a state in which a leg portion of a tower column on the opposite side to overturn according to the embodiment according to the present invention is raised. FIG. 4 is a diagram showing a state in which a steel tower according to an embodiment based on the present invention has fallen and landed. FIG. 5 is a diagram showing a cutting line according to an embodiment according to the present invention. FIG. 6 is a side view illustrating cutting according to the embodiment of the present invention. FIG. 7 is a plan view illustrating cutting according to the embodiment based on the present invention. FIG. 8 is a side view showing cable tension according to an embodiment according to the present invention. FIG. 9 is a plan view showing an arrangement of cables according to the embodiment according to the present invention. FIG. 10 is a diagram illustrating cable pulling according to an embodiment based on the present invention. FIG. 11 is a reference diagram of the tension of the cable 10; FIGS. 12A and 12B are diagrams for explaining the processing of the tower column leg on the side opposite to the fall according to the embodiment according to the present invention, wherein FIG. 12A is a plan view and FIG. 12B is a cross-sectional view taken along line AA in FIG. is there. FIG. 13 is a view for explaining a conventional dismantling of a steel tower. [Description of Signs] T Steel Tower S Main Column Blasting Cut Point K Blasting Cut Point 1 Tower Support 1a Falling Side Support 3 Cutting Piece 10 Cable 15 Jack

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takaya Kawada             1-25-1, Nishi Shinjuku, Shinjuku-ku, Tokyo Taisei             Construction Co., Ltd. F term (reference) 2E176 AA07 AA11 DD31

Claims (1)

Claims 1. A method for dismantling a steel tower in which a steel tower is overturned and then the steel tower is disassembled, wherein a lower part of each of the tower pillars located on a side where the steel tower is overturned is moved in a height direction. Blast cutting at three or more places apart from each other, and before the blast cutting, connect a cable between the lower part of the tower to be blasted and cut and the tower support not to be blasted, and introduce a tensile force to the cable. A method for dismantling a steel tower.