JP5088720B2 - Tank bottom plate replacement method - Google Patents

Description

  The present invention relates to a construction method for replacing a bottom plate of a flat bottom cylindrical tank with a new bottom plate partially or entirely.

  The bottom plate of the outer peripheral ring located at the bottom of the side plate such as an oil tank, that is, the bottom plate such as an annular plate, is easy for rainwater to enter and deforms under a large load, and is likely to be corroded or damaged. The plate thickness was inspected, and those with significant corrosion and damage were conventionally replaced with new bottom plates using the piece method, jack-up method, window opening method, etc.

  Japanese Patent Publication No. 55-41990 (Patent Document 1) is an example of a piece construction method, in which an existing annular plate and a lower part of a side plate in a section are cut and removed, and a new annular plate is inserted and temporarily joined. In this method, a wedge is driven between the two plates, the support piece is fixed, the holding piece is fixed, and the annular plate of the tank is replaced.

  Japanese Patent Publication No. 2-5222 (Patent Document 2) is a construction method in which a jackup construction method is combined with a piece construction method, and the lower part of the side plate is divided into several sections and sequentially melted horizontally to guide the guide pieces on both the inner and outer sides. Affixed to the plate, melted a part of the lower part of the side plate to open several window holes, installed jacks with claws in this window hole, and attached and supported the support piece and guide piece to the entire circumference of the tank sequentially It is an annular plate and bottom plate replacement method for oil storage tanks to be constructed.

  Japanese Patent No. 3709902 (Patent Document 3) is an improved jack-up method of the bottom end plate replacement method of the invention according to the present applicant, as shown in FIGS. A tank that has a hole with a U-shaped cross section installed in the hole and cuts the existing bottom plate connected to the tank, and engages a jack with the flange of this bracket. This is a jack-up method.

Japanese Patent Publication No.55-41990 No. 2-5222 Japanese Patent No. 3709902

  (Patent Document 1) Japanese Patent Publication No. 55-41990 of the above conventional example, the tank annular plate replacement method by the piece construction method cuts and removes the lower side plate, so that the side plate height is reduced and the connection pipe height is adjusted. It took a lot of work.

  Japanese Patent Publication No. 2-5222 is an invention of a construction method in which a jack-up construction method is combined with a conventional piece construction method (Patent Document 2). In order to install the support piece and guide piece to support the entire circumference of the tank in order, it took time and effort to cut and repair the side plates.

Further, in the conventional invention (Patent Document 3) of Japanese Patent No. 3709902 relating to the present applicant, there is provided an opening portion that cuts out an existing bottom plate connected to the lower end portion of the side plate of the tank and penetrates the inside and outside of the tank. This is a tank jack-up method in which a bracket and jack with a U-shaped cross section are provided, and if the reinforcing jig is not used, the lower end of the side plate may be bent and damaged when jacked up. .
Furthermore, since the replacement method of cutting the side plate and the annular plate on the foundation is adopted, the annular plate is pressed against the tank foundation for a long time, and it is difficult to peel off the annular plate. I was worried that it would be damaged.

  The present invention was made to solve the above-mentioned problems in the conventional method, and prevents the deformation of the lower side plate when jacking up the side plate, facilitates the cutting of the annular plate, and further reduces the lower end of the side plate. It is an object of the present invention to provide a tank bottom plate replacement method that facilitates groove processing and allows safe and easy replacement of a bottom plate such as an annular plate.

In the tank bottom plate replacement method according to claim 1, the tank side plate and the annular plate are jacked up so that the tank side plate and the annular plate are lifted from the tank foundation, and a part of the annular plate at the lower end of the tank side plate is lifted off from the tank foundation. Cut the annular plate while leaving it as a circular or polygonal ring-shaped reinforcing ring, jack it up to a predetermined height while leaving it as a ring-shaped reinforcing ring at the lower end of the side plate, and with this jacked up, old and new annular plates, etc. After carrying in and out of the bottom plate, removing the ring-shaped reinforcing ring at the lower end of the side plate and performing groove processing, jack down and weld the lower end portion of the side plate.

The tank bottom plate replacement method according to claim 2 includes a step of attaching a jackup jig to an appropriate position below the tank side plate, and a degree of floating the side plate and the annular plate from the tank foundation using the jackup jig. A step of jacking up and taking off, a step of cutting the annular plate while leaving a part of the annular plate at the lower end of the side plate as a circular or polygonal ring-shaped reinforcing ring in the floated state, and a reinforcing ring at the lower end of the side plate The step of jacking up the side plate and the reinforcing ring to a predetermined height with the remaining state, and the bottom plate such as the existing annular plate cut off and carried out of the tank with the jack up, the new annular plate such as the annular plate is carried into the tank a step of welding bound by, the weld between the reinforcement ring and the side plate while the jack-up A step detach the removed by to reinforcing ring from the side plate, and a step of processing the GMA side plate lower portion in the jack-up, side plates when lowering seat the side plate to a new annular plates using the jack up jig By attaching a guide piece that reinforces the lower part to prevent deformation and prevents the annular plate from springing up, and aligns and welds the groove part of the lower part of the side plate on the annular plate using the guide piece . And a step of joining the side plate and the new annular plate.

According to the tank bottom plate replacement method of the first aspect, the tank side plate and the annular plate are jacked up to the extent that they float from the tank foundation, are taken off, and a part of the tank side plate is left at the lower end of the tank side plate in a state of floating from the tank foundation. Since the round or polygonal ring-shaped reinforcing ring functions as a reinforcing material for preventing deformation of the side plate when jacking up, it is possible to replace the bottom plate such as the annular plate while maintaining a safe jackup state. In addition, since the side plate and the ring-shaped reinforcement ring are jacked up to a predetermined height position, it is easy to perform the welding portion removal work and the cutting work of the annular plate of the ring-shaped reinforcement ring , and the groove processing of the side plate lower end, The bottom plate of the tank can be replaced with good work procedures. Further, since the lower end of the side plate is not cut, the tank capacity can be ensured without reducing the tank height.
In this manner, the annular plate at the lower end of the tank side plate is cut in a state where the side plate and the annular plate are jacked up and taken off so that the side plate and the annular plate are lifted off from the tank foundation. Can be cut without damage, and since the annular plate is separated from the foundation, it can be cut with good workability without causing sparks or rebounding of the cut pieces.

According to the tank bottom plate replacement method of claim 2, the annular plate that is in close contact with the foundation is floated by the step of lifting off the side plate and the annular plate from the tank foundation using the jack-up jig. The cutting process leaves a part of the annular plate at the lower end of the side plate as a ring-shaped reinforcing ring and cuts with good workability without damaging the tank foundation and without causing sparks or rebounding of the cut pieces. it can. In addition, it functions as a reinforcement to prevent deformation of the side plate when jacking up by jacking up with the ring-shaped reinforcing ring remaining at the lower end of the side plate, and the bottom plate such as the old and new annular plates can be used while maintaining a safe jack-up state. Can be carried in and out. Furthermore, workability is not good by a process of processing the GMA side plate lower portion disassociate the ring-shaped annular plate reinforcing ring from the side plate while the jack-up. Further, the side plates are lowered seating, a step of mounting a guide piece for preventing the jumping of the annular plate which prevents the reinforcement deforms the side plate lower when lowering seat the side plate to a new annular plate using the jack up jig By using this guide piece and aligning and welding the groove at the bottom of the side plate on the annular plate, it is possible to prevent the deformation of the bottom of the side plate and to prevent the annular plate from rising. The bottom plate such as the annular plate can be replaced and restored with good work efficiency.

An embodiment of a tank bottom plate replacement method according to the present invention will be described with reference to FIGS.
FIG. 1 shows a state in which a jack-up jig is attached to the outer peripheral position of the tank side plate lower portion, FIG. 2 shows a state in which the side plate and the annular plate are lifted up, and FIG. 3 shows a circular shape with the annular plate in a floating state. The situation of cutting to leave a polygonal ring shape is shown.
FIG. 4 shows a situation where the side plate and the annular plate remaining in the ring shape are jacked up to a predetermined height and the bottom plate such as the annular plate is replaced.
FIG. 5 shows a situation in which the annular plate remaining in the ring shape is deleted from inside and outside, and the lower end of the side plate is grooved from inside and outside.
FIG. 6 shows a situation in which the side plate is jacked down on the new annular plate and welded.

Reference numeral 1 denotes a side plate constituting a flat bottom cylindrical tank, 2 denotes a bottom plate at the lower end of the side plate, that is, an annular annular annular plate, and 3 denotes a circular flat bottom plate connected to the inside of the annular plate.
As shown in FIG. 1, a bracket 6 is attached to an appropriate position on the outer peripheral wall surface of the lower portion of the side plate 1, and a jack-up jig 4 is installed on the jack base 7 on the outer periphery of the tank so as to support the lower portion of the bracket 6. . Although not shown in the drawing, a plurality of jack-up jigs 4 are provided separately along the outer periphery of the tank so that the entire tank can be jacked up and down on average.

In order to replace the bottom plates such as the annular plate 2 and the bottom plate 3, it is necessary to cut off the lower end portion (X) of the side plate 1, but in the present invention, the vicinity of the lower end portion (X) of the side plate 1 is not cut. (Y) of the annular plate 2 is cut, and a part of the annular plate 2 is left as a circular or polygonal ring-shaped reinforcing ring 9 at the lower end edge of the side plate 1.
Thus, by cutting the position (Y) in the figure, it is not necessary to cut the upper position from the lower end (X) of the side plate 1 or to provide a window hole or opening.

In the embodiment shown in FIG. 2, the annular plate 2 and the side plate 1 are jacked up to the extent that they float from the tank foundation 5. The vicinity of the cutting position of the annular plate 2 is taken off from the tank base 5 to about 50 mm by this jack-up, and then the position (Y) in the figure is cut.
The annular plate 2 that has been pressed against the side plate 1 for a long time and is in close contact with the tank foundation 5 is easily detached from the tank foundation by applying a light impact such as hammering or the like. Asphalt mortar can be easily removed by light hammering.

As shown in FIG. 3, the position of (Y) is cut so that a part of the annular plate 2 jacked up and floated is left as a reinforcing ring 9 having a circular or polygonal ring shape.
Thus, by leaving a part of the annular plate 2 as the reinforcing ring 9, when the side plate 1 is jacked up, there is no fear that the lower side plate will be deformed by the load, and there is no need to separately attach a reinforcing jig for preventing deformation. .
The annular plate 2 is cut using a cutting machine 8 by gas cutting or arc air gouging.
At the time of this cutting, the vicinity of the cutting position of the annular plate 2 floats from the tank foundation 5, so that the asphalt mortar and the like of the tank foundation 5 are not cut or damaged by the flame or heat of gas cutting. Moreover, since the annular plate 2 is pulled away from the tank foundation 5 during the cutting operation, the cutting operation is easy without causing an arc or a cut piece to escape into the lower space and causing an upward rebound. .

FIG. 4 shows a situation where the side plate 1 and the annular plate reinforcing ring 9 left in the ring shape are jacked up to a predetermined height and the bottom plate such as the annular plate is replaced.
(A) The existing annular plate 2 and bottom plate 3 were pulled out and carried out of the tank using the space between the jacked up side plate 1 and the tank foundation 5, and the tank foundation 5 was corrected as necessary. Thereafter, (B) a new annular plate 12 and a new bottom plate 13 are carried in, arranged and welded together. The height of the jack-up is such that the annular plate 2 and the bottom plate 3 can be easily carried out, the foundation can be easily modified, the bottom plate such as the new annular plate 12 can be easily carried into the tank, and in the event of an emergency such as a storm. Set the height so that it can be jacked down quickly and easily.

FIG. 5 shows a situation in which the groove portions 10 </ b> A and 10 </ b> B are formed by removing the reinforcing ring 9 at the lower end (X) of the side plate 1 using the space below the jacked up side plate 1.
The reinforcement ring 9 is cut and removed from both the inside and outside of the tank by arc air gouging, gas cutting, grinder grinding, etc., and then the groove and shaping of the lower end of the side plate are performed to weld the new annular plate and the lower end of the side plate. The groove portions 10A and 10B are formed.
Since the work of removing the reinforcing ring 9 and the work of groove processing of the lower end of the side plate can be performed at a moderately high posture position from both the inside and outside of the tank, the work can be appropriately performed with good workability.

  As shown in FIG. 6, the side plate 1 is jacked down on the new annular plate 12 using the jack-up jig 4, that is, is lowered and seated. At this time, the guide plate 14 is used to reinforce the lower portion of the side plate to prevent deformation, and the annular plate 12 is prevented from springing up and aligned as shown by the horizontal arrows in the figure, and the welded portion 15 The groove portions 10A and 10B are welded.

  As mentioned above, there is no change in tank side plate height because the lower part of the side plate is not cut off, and there is no need to repair the tank side plate because there is no window hole or opening by cutting the lower part of the side plate. The bottom plate such as the annular plate can be replaced and restored with good workability by preventing the deformation of the lower side plate.

  Various structures such as tanks with damaged foundations as well as bottom plates can be used for replacement and repair work.

It is side section explanatory drawing which shows the state which attached the jackup jig | tool to the appropriate position of the lower part of a side board in the embodiment of the replacement method of the tank bottom board concerning this invention. FIG. 2 is an explanatory side sectional view showing a state where the side plate and the annular plate are jacked up to the extent that the side plate and the annular plate are floated. FIG. 3 is an explanatory view showing a situation where a part of the annular plate is cut so as to remain in a ring shape at the lower end of the side plate, following FIG. 2. FIG. 4 is an explanatory diagram showing a situation in which, following FIG. 3, the side plate and the annular plate remaining in the ring shape are jacked up to a predetermined height, and the bottom plate such as the annular plate is replaced. It is explanatory drawing which shows the condition which deletes the annular plate partially left in the ring shape from both the inside and outside both sides, and carries out groove processing of the side plate lower end part. FIG. 6 is an explanatory diagram showing a situation in which welding is performed by jacking down a side plate on a new annular plate, following FIG. 5.

Explanation of symbols

1 side plate
2 Annual Plate
3 bottom plate
4 Jack-up jig
5 basics
6 brackets
7 jack base
8 cutting machine
9 Reinforcing ring
10A, 10B Groove

12 new annular plates
13 New bottom plate
14 guide pieces
15 welds

Claims (2)

The tank side plate and the annular plate are jacked up to the extent that they float from the tank foundation, take off and leave a part of the annular plate at the lower end of the tank side plate as a circular or polygonal ring-shaped reinforcing ring. Cut the annular plate, jack it up to a specified height while leaving it as a ring-shaped reinforcement ring at the lower end of the side plate, and with this jack up, carry in and out the bottom plate such as the old and new annular plates , A tank bottom plate replacement method characterized by removing a reinforcing ring and performing groove processing, then jacking down and welding a lower end portion of a side plate. A step of attaching a jack-up jig to an appropriate position under the tank side plate, a step of jacking up the side plate and the annular plate so that the side plate and the annular plate are lifted from the tank foundation using the jack-up jig, and taking off the side plate. A step of cutting the annular plate while leaving a part of the annular plate at the lower end as a circular or polygonal ring-shaped reinforcing ring, and jacking up the side plate and the reinforcing ring to a predetermined height with the reinforcing ring at the lower end of the side plate remaining Cutting the existing bottom plate such as an annular plate in the jacked-up state and carrying it out of the tank, bringing the bottom plate such as a new annular plate into the tank and welding it together, and the reinforcing ring in the jacked-up state a step detach the removal to reinforcing ring welded portion between the side plates from the side plate and, A step of processing the GMA side plate lower portion in Yakkiappu, the bounce of the annular plate which prevents the reinforcement deforms the side plate lower when lowering seat the side plate to a new annular plates using the jack up jig Attaching the guide plate to prevent, and joining the side plate and the new annular plate by aligning and welding the groove portion of the lower side plate on the annular plate using the guide piece. A tank bottom plate replacement method characterized by

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