JPS60138172A - Disassembling and repairing method of side wall of steel cyclindrical structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Object of the Invention) The present invention relates to the dismantling of side walls of large steel-clad cylindrical structures, such as crude oil tanks and steel silos for storing grain and powder, which are installed as ancillary equipment of petrochemical plants. The purpose is to provide a safe demolition and repair method that has a short construction period, does not require high-altitude work, and limits the use of fire to narrow spaces. Conventional technology and its problems - Conventionally, when dismantling and repairing a large cylindrical structure made of M, the first step is to repeatedly perform gas cutting and removal operations from the top of the structure downwards. A common method is to dismantle the repaired area and then install new parts to complete the repair.

In recent years, structures such as crude oil tanks and LPG tanks and silos have tended to become larger1, with a height of more than 20 meters,
Some trees reach heights of 40 to 50 meters.

Therefore, when dismantling and repairing these large structures, large-scale scaffolding must be erected on the entire side wall of the structure, or
Special consideration is required to ensure work safety, such as installing safety nets all over the area to prevent workers from falling. Ta.

In addition, storage tanks, which are structures to be demolished, are considered part of the equipment in chemical plants and oil depots. In most cases, the handling of fire during demolition and repair work is strictly restricted when other equipment is in operation, resulting in a decrease in work efficiency and damage to surrounding equipment. It was necessary to invest a large amount of money into measures to prevent ignition. That is, in the conventional demolition and repair method, fire is used for gas cutting or the like over a wide area over the entire side wall of the structure, which poses safety problems such as the scattering of fire.

Furthermore, according to the conventional method, it is necessary to lower or lift the cut pieces from a high place all around the structure, and for this purpose, large crane equipment for heavy loads with a high lifting height is required. In addition, there was a need for enough work space to allow the crane equipment to move around the entire perimeter of the structure.

Furthermore, as a construction method for partially replacing the side walls of storage tanks, the Jasuki Amp and Jasuki Down methods have been used.

In other words, the entire storage tank is lifted and lowered by means such as jacks,
Temporarily raise and hold the parts, then dismantle and remove the parts that need to be replaced (mainly the bottom plate and the lower part of the side walls), then assemble the core part with new parts, and then lower the storage lv and 10,000 parts and join them. With this conventional method, if the height of the side wall to be replaced and repaired is low, it is relatively easy to dismantle the corroded part, replace it with a new member, and repaint it with a single jacking operation. If the corroded part of the side wall is spread over a wide area and its height exceeds or exceeds the height of the storage tank side wall, it is necessary to perform the jacking operation several times, and it is necessary to attach a jig. On the other hand, there was a drawback that a large number of workers were required to perform the jacking operation.

Note that impurities contained in stored substances, rainwater, corrosive substances, etc. tend to settle on the bottom and lower surrounding walls of storage tanks, so corrosion is particularly noticeable near the bottom of the bottom plate and surrounding walls. Yes, there are 10,000 I# units that need urgent replacement.
The roof and the upper part of the surrounding wall are relatively less corroded and therefore do not need to be replaced in many cases.In that case, it would be economical to replace only the corroded part of the lower side plate. However, if the corroded part that needs to be replaced is at a height of 7 to 8 m above the ground, it is necessary to raise and lower the structure many times by lifting means such as jacks just to dismantle and remove the corroded part. Furthermore, when assembling new parts, there was a similar problem in that it was very inefficient and required a lot of labor.

(Structure and operation of the invention) The present invention proposes a new construction method that solves the above-mentioned problems and enables safe and efficient demolition and repair work. Near the ground of the structure, cut the side wall around the entire circumference along a cutting line with an inclination of -Y with respect to the horizontal, separate it into the upper and lower peripheral walls, and apply a load to the entire upper end of the lower peripheral wall. A process of cutting and removing the side wall member of the structure corresponding to the lowest part of the upper peripheral wall from a state in which an appropriate number of support rollers are arranged and the upper peripheral wall is rotatably placed on these rollers, and after the removal. The process of rotating and lowering the upper peripheral wall part on a roller is repeated alternately in order to fill the created space 1
A process of performing demolition work at a low location by sequentially cutting and removing the main structure to be demolished from the bottom, then inserting a new peripheral wall member into the removed side wall space and joining it to the lower edge of the upper peripheral wall. The process of assembling the surrounding wall to a predetermined height by alternately repeating the process of rotating the entire upper layer wall in the opposite direction to that used during demolition work and raising it up to form a new space reduces repair work. It's in the place where you do it.

Next, the demolition/repair method of the present invention will be explained according to the embodiment shown in the drawings. The drawing shows an example of an @kai that disassembles and repairs a cylindrical storage tank with a spherical roof.

FIG. 1 is a perspective view showing a state in which the side wall of an existing cylindrical storage tank U is cut around the ground by cutting 1 (R) having a constant inclination with respect to the horizontal. Cutting line (R
) is provided around the storage tank circumferential wall 121'E so as to be inclined at a constant angle with respect to the horizontal direction, with the starting point (S) near the bottom plate of the storage tank as shown in the figure. Therefore, the cutting cut is It has a spiral shape.

The difference in level (l() is usually 2
The height difference is approximately 3 m, and this step corresponds to the height of the peripheral wall member (6) to be removed in one dismantling operation.

With this cutting line (R) as the boundary, the storage tank has a spherical roof fi+
It is vertically divided into two parts: an upper circumferential wall section (3) including an upper circumferential wall section and a lowermost circumferential wall section (4).

FIG. 2 is a diagram showing a state in which the upper circumferential wall (3) has been raised by jacking or the like from the state shown in FIG. 1, and a load supporting roller (5) has been disposed between it and the lowermost circumferential wall (4). As shown in an enlarged view in FIG. 5, this cargo support roller 151 has a plurality of them with an appropriate opening (curvature of about 2 to 5 m) all around the upper end of the lowermost peripheral wall (4). The rollers (5) are configured to rotatably support the upper and lower peripheral walls (3).

Next, in this state, the peripheral wall member (6) of the structure to be demolished corresponding to the lowest part of the upper peripheral wall (3) is cut by means such as gas cutting, and then lifted up by a small crane or the like and removed. In other words, in FIG. 2, the cutting schedule 1t7 is indicated by a broken line on the extension of the spiral cutting line (R).
1, and cut out the peripheral wall member +61. Note that the length of the member (6) is usually set to about 6 m in consideration of the maximum length that can be carried out by a vehicle.

FIG. 5 is a perspective view showing the state immediately after the peripheral wall member (6) is removed, and a space (8) is formed in the removed portion.

Next, by driving the roller (5), the upper peripheral wall portion (3) is rotated by a predetermined amount in the same direction as the arrow. Then the fourth
As shown in the figure, the upper peripheral wall part (3) descends while rotating along the spiral part so as to fill the space (8).

In this way, the peripheral wall portion that requires repair is dismantled and removed by alternately repeating the process of cutting and removing the peripheral wall member (6) and the process of rotating and lowering the entire upper peripheral wall part (3). Next, work begins on assembling new surrounding wall members into the removed surrounding wall portions.

In other words, a new plate material corresponding to the removed peripheral wall member is installed in accordance with the reverse procedure of the F## construction method described above.

In other words, the installation work is based on the construction method conventionally called the helical construction method, and the space shown in Figure 3 (
Insert a new peripheral wall member into 8) and join it to the lower edge of upper tier 4 system 3), then upper tier a! [All 131 pieces are rotated on rollers in the opposite direction to the one used during disassembly, raised to form a new space, and the same procedure is repeated to assemble the peripheral wall to a predetermined height. ) is removed and the upper peripheral wall part (3) and the lowermost peripheral wall part (4) are joined, completing all the M body repair work.

(Effects of the Invention) As is clear from the above explanation, according to the present construction method, through the steps described above, assembly work can be performed continuously in the reverse order of disassembly work, and in the case of the conventional Jasokiup construction method, There is no need for any setup changes such as changing the necessary jigs, and the work can proceed efficiently.

In addition, according to this construction method, all maintenance and repair work on the structure is carried out at a low place near the ground, so first of all, unlike the conventional construction method, which starts by dismantling the structure from the top. In addition, there is no need to install huge amounts of imitation scaffolding or safety nets all around the structure, which can significantly reduce construction costs.

Secondly, most of the demolition and repair work is carried out close to the ground level and in arbitrarily limited areas, so so-called work at heights is avoided, making it possible to perform highly safe and efficient work. be. Furthermore, a small crane is sufficient for removing the peripheral wall members. Furthermore, there is no need to secure open space all around the structure as a continuous path for the movement of the crane.
! ! Since the work area required is small, this construction method exhibits excellent effects and maneuverability, especially in cases where there are other existing structures around the structure.

Sixth, since the most dangerous process of cutting with fire is carried out in a narrow, low-lying area, it is easy to ensure safety against fire, and safety is maintained even when equipment around the structure is in operation. You can proceed with your work.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a state in which an existing cylindrical storage tank is cut around the entire circumference of the storage tank near the ground so that the cut section has a spiral shape. In FIG. 2, the upper circumferential wall portion (3) is raised from the state shown in FIG.
FIG. FIG. 6 is a perspective view showing the state of the interview after removing the surrounding wall material (field). FIG. 4 is a perspective view showing a state in which the upper circumference ag+3+ is rotated in the direction of the arrow from the state shown in FIG. 6 to fill the space (8) in FIG. 3. FIG. 5 is an enlarged perspective view of the load supporting roller (5). Il+ --------- One spherical roof +21 ------ One storage wall + 31 ---
-----Upper peripheral wall +41-1---Lowermost peripheral wall 15J---
−−−−One load support roller +61−−−−−−−−
One circumferential wall member (7) --1111~--Planned cutting line +8)-- Space (1-1-- Spiral cutting line (H) ---
−−=−1 step difference (S) −−−−−−−−−First point (L) −−−1~−−−−End point

Claims (1)

[Claims] When dismantling and repairing the prepared cylindrical structure +11JI wall, first, near the ground level of the existing structure, the side wall was cut all around along a cutting line that had a certain inclination to the horizontal, and the wall was separated into the upper and lower peripheral walls. Load support rollers are disposed at predetermined intervals around the entire upper end of the lower peripheral wall, and the upper peripheral wall is placed on the load supporting four rollers in a rotational manner to the lowest side J114T' of the upper peripheral wall. By repeating the process of cutting and removing material A and the process of lowering the upper peripheral wall by rotating it on rollers so as to fill the space created in the removed part, the structure can be constructed in the first place. The process of cutting and removing the necessary side wall parts sequentially from the bottom, then inserting a new IFJ wall member into the removed side wall space and joining it to the lower edge of the upper peripheral wall, and removing the entire upper peripheral wall. The process of rotating in the opposite direction to the one used during the Kui-Qin era and raising the wall to form a new space is repeated alternately to build up the surrounding wall to a predetermined height, allowing repair work to be carried out at a lower location. A method for dismantling and repairing side walls of cylindrical structures.