JPH0410956B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wire sawing method for buildings, bridges, foundations, and other reinforced concrete structures.

[Conventional technology]

Disc blade type cutting machines have traditionally been widely used for partial demolition of reinforced concrete structures by cutting, but there are some issues with blade manufacturing, workability, etc.
Because they are small and lightweight for handling reasons, their cutting ability is poor, the cutting cross-sectional area is limited to a narrow range, and the maximum cutting depth is about 30 to 40 cm. Further, in the case of partial disassembly by rotating such a disc blade, there are problems such as overcutting is required even in areas that do not require cutting.

In order to solve these problems all at once, the present inventor has recently developed a construction method for cutting and dismantling reinforced concrete structures by wire sawing. In this construction method, a cutting cable made of a wire rope with cutting ability is hung on a reinforced concrete structure, and the cutting cable is circulated by a cable drive device while controlling the running speed and tension.

In this case, the cutting cable usually has a structure in which, for example, beads having a layer of diamond abrasive grains are arranged on a wire rope at appropriate pitches, with or without using a coil spring or other spacer. In addition, the cable drive device has a structure that includes, for example, a cable drive pulley around which a cutting cable is wound, a hydraulic motor, electric motor, or other prime mover that rotates the cable drive pulley, and other attached mechanisms. A device that moves along a rail, specifically a device that moves on a rail using drive wheels, a device that moves on a rack using a drive pinion, etc. are used as appropriate.

[Problem that the invention seeks to solve]

When wire sawing reinforced concrete structures, the cutting cable generally runs smoothly with a relatively gentle bend from the beginning to the middle of the cutting process, that is, with a large radius of curvature, cutting not only the concrete layer in contact but also the reinforcing steel without any problems. do. However, at the end of the cutting process, when the diameter and cross-sectional area of the uncut portion become smaller, the cutting cable also becomes smaller.
Since the wire rope in the cutting cable runs with small sharp bends at the part where it comes into contact with the uncut part, the metal fatigue of the wire rope in the cutting cable progresses, and the beads and spacers, etc., which cannot be bent together with the wire rope, are especially prone to pulling against the reinforcing steel. Once hooked, the running of the cutting cable is obstructed, and an abnormal load is applied to the wire rope, causing problems such as breakage of the wire rope and damage to the spacer and the like. When the wire rope of a cutting cable breaks during wire sawing of a reinforced concrete structure, it is necessary to repair the broken connection, replace it with a new cutting cable, or even reinstall the cutting cable. Wire sawing is interrupted, resulting in a significant drop in productivity.
There were also other problems, such as the broken cutting cables separating from the reinforced concrete structure and flying off, posing a danger to the surrounding area.

Further, even if there is no breakage accident as described above during wire sawing, the cutting cable has the problem of separating from the reinforced concrete structure and flying off as soon as cutting is completed, posing a danger to the surrounding area.

An object of the present invention is to prevent the running cutting cable from forming the above-mentioned small sharp bends that could lead to breakage at the end of cutting when wire sawing reinforced concrete structures.
Furthermore, it is an object of the present invention to provide a wire sawing method in which the cutting cable separated from the reinforced concrete structure does not fly around when cutting is finished.

[Technical means to solve problems]

The wire sawing method for reinforced concrete structures according to the present invention involves installing a pair of guide pulleys along the surface of the reinforced concrete structure on the same plane as the planned cutting surface, and inserting a cutting cable into the reinforced concrete from the outside of one of the guide pulleys. It is arranged so that it is hung on a structure and pulled out from the inside of the other guide pulley, and is allowed to circulate endlessly under adjustment of tension and running speed.

In addition, in the wire sawing method described above, a pair of guide pulleys are placed along the surface of the reinforced concrete structure on the same plane as the planned cutting surface, and each guide pulley is Install an auxiliary guide pulley adjacent to each guide pulley that has a common tangent line passing through the pulley groove, pass the cutting cable through one of the auxiliary guide pulleys, and connect it to the reinforced concrete structure from the outside of the adjacent guide pulley. Partially changed to a configuration in which the guide pulley is hung, passed through the inside of the other guide pulley, and pulled out from the auxiliary guide pulley adjacent to it, and is allowed to circulate endlessly under adjustment of tension and running speed. be able to.

Note that the wire sawing method according to the present invention may be employed from the initial stage of cutting as described above, but it may also be employed from the middle or final stage of cutting when its effects are particularly desired.

The present invention will be explained below based on embodiments shown in the drawings.

In FIGS. 1 and 2, which are a plan view and a side view illustrating the wire sawing method for a reinforced concrete structure according to the present invention, a rectangular column-shaped reinforced concrete structure 2, which is an object to be cut, is suspended above a road surface 1, The reinforced concrete structure 2
is constructed by arranging reinforcing bars 4 in the axial direction within a concrete layer 3. The guide pulley stand 5 is attached to the anchor 6 on the surface of the reinforced concrete structure 2.
The guide pulley stand 5 has a pair of horizontally oriented guide pulleys 7a,
7b, and a pair of vertically oriented auxiliary guide pulleys 8a, 8b, which are adjacent to the guide pulleys 7a, 7b and have a common tangent line passing through the pulley grooves, are each rotatably mounted on a shaft. Note that the guide pulleys 7a, 7b and auxiliary guide pulleys 8a, 8
It is more convenient to handle and install b if they are integrated by the guide pulley stand 5 as described above, but there is no problem if they are installed separately, and if they are not fixed to the reinforced concrete structure 2, It may be installed on an object, for example, a road surface 1.

On the other hand, a reinforced concrete structure 2 is placed on the road surface 1.
A second guide pulley stand 9 is fixed by an anchor 10 at a slight distance from the second guide pulley stand 9, and a rail 11 is laid adjacent to it. On the second guide pulley 9, vertically oriented loose side guide pulleys 12, 13 and a tight side guide pulley 14 are rotatably mounted, and a cable drive device 15 is movably installed on the rail 11. . The cable drive device 15 includes a cable drive pulley 16, its drive mechanism (not shown), and a rail 1.
1 and a drive mechanism thereof (not shown).

As shown by the broken line in the drawing, the cutting cable 18 is hung on the cable drive pulley 16, starts from its slack side, passes through the slack side guide pulleys 12 and 13, passes through one of the auxiliary guide pulleys 8a, and then passes through the slack side guide pulleys 12 and 13, and then passes through the slack side guide pulleys 12 and 13. Adjacent guide pulley 7a
wrapped around the reinforced concrete structure 2 from the outside, passing inside the other guide pulley 7b,
It is arranged in an endless state so that it is pulled out from the auxiliary guide pulley 8b adjacent thereto and returned to the tension side of the cable drive pulley 16 via the tension side guide pulley 14.

For example, when it is necessary to cut only a predetermined section of the reinforced concrete structure 2 when partially cutting or forming an opening, instead of wrapping the cutting cable 18 around the entire circumference of the reinforced concrete structure 2, It may be hung by passing it through one or two perforations (not shown) that are passed through it.

[Action of the invention]

In the above, while operating the cable drive device 15 and urging it to move along the rail 11 in the right direction in the drawing, the cable drive pulley 16
When the cutting cable 18 is driven to rotate, the cutting cable 18 circulates under the required tension, and the reinforced concrete structure 2 that comes into frictional contact with the cutting cable 18 is gradually cut from its surface to the inside.

Note that the guide pulleys 7a and 7b are oriented horizontally in the case of horizontal cutting as described above, but the same is true in the case of inclined cutting or vertical cutting, and they are installed on the same plane as the planned cutting surface. Further, an auxiliary guide pulley 8 for the guide pulleys 7a and 7b
Although the installation angles of a and 8b are right angles in the above case, angles other than right angles may be adopted depending on the arrangement of the cutting cable 18 to the cable drive pulley 16. Since the guide pulleys 7a, 7b and the corresponding auxiliary guide pulleys 8a, 8b share a tangent line passing through the pulley groove, the cutting cable 18 is connected to the cutting guide pulleys 7a, 7b and the corresponding auxiliary guide pulley along the tangent line. 8
It is possible to smoothly bridge the gap between a and 8b so that it can run.

In addition, the auxiliary guide pulleys 8a, 8b, the slack side guide pulleys 12, 13, the tight side guide pulley 14, etc. are used as a cable drive device on the road surface 1 to drive the endless cutting cable 18 hung over the upper cut point of the reinforced concrete structure 2. This serves to smoothly guide the cable drive pulley 16 to the 15 cable drive pulleys 16. Therefore, depending on the arrangement relationship between the cutting location and the cable drive pulley 16, they may not be necessary, or guide pulleys of another type may be installed on the road surface 1, the reinforced concrete structure 2, the cable drive device 15, etc. Ru.
For example, when the cutting point is below the cable drive device 15, for example, when wire sawing the root of the reinforced concrete structure 2 in water using the cable drive device 15 installed on land, the auxiliary guide pulley 8a , 8b may be installed above the guide pulleys 7a, 7b to guide the cutting cable 18 upward.

As the cutting progresses, the cutting cable 18
The contact portion with the reinforced concrete structure 2 travels while bending, and the bent portion gradually moves in the direction of the guide pulleys 7a and 7b. Since it is arranged inside the other guide pulley 7b via the reinforced concrete structure 2, even at the end of cutting, the tension side of the cutting cable 18 that is hung over the uncut part of the reinforced concrete structure 2 and the loose side are separated. Since the distance between the two sides is not narrower than the distance between the outside of one guide pulley 7a and the inside of the other guide pulley 7b, the bending of the contact area is not extreme, as shown by the dashed line in the drawing. It does not become small and sharp or bend, and the cutting cable 18 is less likely to break. Note that it is preferable to install the guide pulleys 7a and 7b so that the distance between the tight side and the loose side of the cutting cable 18 is appropriately wide.

Moreover, even if the cutting cable 18 separates from the reinforced concrete structure 2 after cutting is completed, the cutting cable 18 is stopped by one of the guide pulleys 7a, so that dangerous jumping does not occur.

Incidentally, when comparing the wire sawing method of the above embodiment with other wire sawing methods, in FIG. 3, which is a plan view of another wire sawing method for a reinforced concrete structure, a pair of The guide pulleys 7c and 7d are arranged horizontally, and the cutting cable 18 is passed through the inside of one guide pulley 7c and hung on the reinforced concrete structure 2, as shown by the broken line in the drawing, and the cable 18 is passed through the inside of the other guide pulley 7d. Although not shown, it is disposed so as to be able to circulate in an endless manner as in the above embodiment.

Even in this case, there is no problem because the cutting cable 18 runs with a relatively large bend in the early and middle stages of cutting, but at the end of cutting, the bend is small and sharp, as shown by the chain double-dashed line in the drawing. Become,
The vehicle will be running unstable with most of the bends.

〔Effect of the invention〕

After all, in the wire sawing method for reinforced concrete structures according to the present invention, the cutting cable is hooked onto the reinforced concrete structure from the outside of one of the guide pulleys, and even at the final stage of cutting, the cutting cable is hooked onto the uncut portion of the reinforced concrete structure. When wire sawing reinforced concrete structures, the distance between the tight side and the loose side of the guide pulley cannot be narrower than the distance between the outside of one guide pulley and the inside of the other guide pulley.
At the end of cutting, the running cutting cable does not form small sharp bends or folds that could lead to breakage, and the wire rope is prevented from breaking due to metal fatigue or damage to the spacer, etc.

In addition, in this wire sawing method, the cutting cable is hooked onto the reinforced concrete structure from the outside of one of the guide pulleys, so even after the cutting is completed and separated from the reinforced concrete structure, the cutting cable remains attached to the guide pulley. It can be stopped and therefore cannot fly off and pose a danger to the surrounding area.

Furthermore, in this wire sawing method, if an auxiliary guide pulley is installed adjacent to each guide pulley, the cutting cable can be guided smoothly from each guide pulley in the desired direction, allowing for a variety of installations. .

[Brief explanation of drawings]

FIGS. 1 and 2 are a plan view and a side view illustrating a wire sawing method for a reinforced concrete structure according to the present invention, and FIG. 3 is a plan view of another wire sawing method for a reinforced concrete structure. <Description of main symbols>, 2...Reinforced concrete structure, 7a, 7b...Guide pulley, 8a,
8b... Auxiliary guide pulley, 15... Cable drive device, 18... Cutting cable.

Claims (1)

[Claims] 1. A pair of guide pulleys are installed along the surface of the reinforced concrete structure on the same plane as the planned cutting surface, and a cutting cable is hung from the outside of one of the guide pulleys onto the reinforced concrete structure while the other Wire sawing method for reinforced concrete structures, which consists of a wire sawing method for a reinforced concrete structure, which is arranged so as to be pulled out from the inside of a guide pulley and run in an endless cycle while adjusting the tension and running speed. 2 Along the surface of the reinforced concrete structure, install a pair of guide pulleys on the same plane as the planned cutting surface, and install an auxiliary guide pulley adjacent to each guide pulley that shares a tangent line passing through the pulley groove with each guide pulley. Pass the cutting cable through one of the auxiliary guide pulleys,
It is arranged so that it is hung from the outside of the adjacent guide pulley to the reinforced concrete structure, passed through the inside of the other guide pulley, and pulled out from the auxiliary guide pulley adjacent to it, and circulated in an endless state under the adjustment of tension and running speed. A wire sawing method for reinforced concrete structures that involves running. 3. The wire sawing method for reinforced concrete structures according to claim 2, wherein each auxiliary guide pulley is oriented at right angles to the adjacent guide pulley.