JP2017039513A - Method for repairing existing tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for repairing an existing tank by replacing bottom plates and the lowest stage side plates without generating moment in the side plates, and furthermore, foundation work can be also done.SOLUTION: A method for repairing an existing tank comprises: providing opening parts (5) in last stage side plates (2) when an existing tank is repaired; attaching supporting members (8) to the respective opening parts to support the tank (1) at directly under the side walls; provide openings (13) under lower ends of the respective side walls over the whole circumference with a height corresponding to the opening parts and support members; and while keeping supporting the tank in a natural attitude, performing replacement of bottom plates, foundation work and replacement of the lowest stage side walls.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a construction method (method) for repairing an existing tank for storing dangerous or non-hazardous materials installed in facilities such as petroleum refining, petrochemical and chemical factories, oil tanks, and the like. More specifically, among these existing tanks, especially in the maintenance, management and maintenance of all-welded vertical cylindrical tanks made of steel, the lowermost side plate, annular plate, bottom plate, etc., of the tank are replaced (updated) and the foundation is revised. It is related to the construction method for performing etc.

  After installation, the tank is constantly managed and regularly inspected to ensure safety, and repairs and repairs are performed as necessary.

  In particular, corrosion of the tank due to aging is unavoidable, and some or all of the bottom plate is replaced depending on the state of corrosion. In recent years, attention has been paid to deterioration of the side plate of the tank, and it is expected that the number of cases in which the side plate needs to be replaced will increase in the future.

  Related laws and regulations are frequently revised to ensure the safety of such tanks, and new standards are set as needed to deal with disasters such as earthquakes and accidents resulting from them.

  In order to properly repair existing tanks and ensure safety while conforming to standards that are changed from time to time, various tank repair methods have been proposed and used according to the purpose and target of the repair.

  For example, to replace an annular bottom plate (annular plate) or other bottom plate, a so-called piece method is used in which a predetermined opening is provided at the bottom of the tank and a support piece or the like that supports the bottom of the tank side plate is attached in the vicinity of the opening. A relatively simple construction method such as (Patent Document 1) can be used.

  On the other hand, when accompanied by foundation work such as unequal settlement correction work, it has been necessary to use a larger apparatus. The main construction method is a so-called jack-up construction method in which a tank is lifted by using a plurality of hydraulic jacks and journal jacks (hereinafter referred to as “hydraulic jacks”) to perform foundations and other work (for example, Patent Documents 2-4).

  In the jack-up method, the plate is usually reinforced on the peripheral surface of the second-stage side plate from the bottom, a bracket is attached, and the whole tank is lifted by supporting it with a plurality of hydraulic pressures. Therefore, the jack-up method has a problem that the side plate is easily deformed by a moment generated by being pushed from either the outer peripheral surface or the inner peripheral surface of the side plate.

  In order to prevent deformation of the side plate due to the moment and to ensure roundness, in this construction method, detailed and detailed strength calculation is performed, and in addition to this plate reinforcement, there are a number of longitudinal reinforcements and circumferential reinforcements. A lot of labor and time are unavoidable, such as attaching reinforcing materials and removing them after the work is completed.

  In addition, when attaching and removing these reinforcing members and brackets, there is a possibility that the side plate to be attached (the side plate used even after tank repair) is damaged.

  Therefore, it becomes necessary to inspect the state after the removal of the large number of reinforcing members and brackets in detail.

Furthermore, in this construction method, a hydraulic jack or the like is installed on the ground around the lower end of the tank, and the weight of the entire tank is applied to it. Therefore, it is necessary to calculate the strength of the installation ground and perform basic maintenance beforehand.

  Patent document 5 is proposed as a measure against the moment generated in the side plate in the jack-up method. However, in the invention of Patent Document 5, if the reinforcing jig is not used, there is a problem that the lower end portion of the side plate may be bent and damaged when jacked up.

  Accordingly, it has been proposed to leave a part of the bottom plate at the lower end of the tank side plate in a circular or polygonal ring shape, cut the bottom plate, and jack up to a predetermined height while leaving the ring-shaped bottom plate at the lower end of the side plate. (Patent Document 6). However, in the invention of Patent Document 6, the bracket attached to the outer periphery of the side plate is jacked up by a jack, and the problem of moment generated in the side plate is not solved.

  As mentioned above, existing tanks must be refurbished to ensure safety, and compliance with standards is also a legal obligation. These often require foundation work, not just replacement of the bottom plate. Nevertheless, only a relatively large-scale construction method exists for this purpose, and the jack-up construction method, which is the main construction method, has the above-mentioned problems.

JP 54-30521 A JP-A-57-1414489 JP-A-11-208777 JP 2006-56525 A JP 09-228680 A JP 2008-230694 A

  The present invention has been made in view of the above problems, and can be used to replace the bottom plate, the lowermost side plate of the side plate, and to perform foundation work without causing a moment on the side plate. It is an issue to provide.

  In order to solve the above-mentioned problems, the present invention attaches a support tool to the lowermost stage of the side plate to be replaced when the existing tank is repaired, and an opening having a height corresponding to the support tool is provided at the lower end of the side plate over the entire circumference. Provide. As a result, the tank is supported by the support tool directly below the side plate while maintaining a natural posture (original posture of the tank). In such a state, after the bottom plate is replaced and the foundation work is performed, the bottom side plate which is the receiving portion of the support is replaced with a new side plate.

  That is, the present invention provides (a) a plurality of openings having a height of about 0.5 m to about 0.7 m at the lowermost part of the lowermost stage of the existing side plate of the existing tank, and a portion positioned below the opening on the existing bottom plate. A step of cutting each, (b) a step of installing a support that supports the lowermost step of the existing side plate in each opening, (c) a lowermost portion of the lowermost step of the existing side plate is cut at the height of the opening, A step of providing an opening over the entire circumference at the bottom, (d) a step of cutting and removing the existing bottom plate from the opening over the entire circumference, (e) a step of performing foundation work, and (f) a new bottom plate over the entire circumference. There is provided a method for repairing an existing tank, characterized by comprising a step of carrying in and laying through an opening extending over, and (g) a step of replacing the lowermost step of the existing side plate with a new side plate over the entire circumference.

  According to the present invention, the bottom plate and the bottom plate of the side plate can be replaced and the foundation work can be performed in a state where the tank is supported in a natural posture without generating a moment on the side plate.

It is a figure which shows the cylindrical tank (state before implementation of this invention) in one Embodiment of this invention. It is a figure which shows the example of the existing bottom plate of a cylindrical tank. (A) shows the example (example of the bottom plate which concerns on this embodiment) in which the cyclic | annular bottom plate is provided, (b) shows the example in which the cyclic | annular bottom plate is not provided. It is a figure for showing a series of processes in one embodiment of the present invention. It is a figure for showing a series of processes in one embodiment of the present invention. (A) is a figure which shows an example of the support tool in one Embodiment of this invention, (b) is a figure which shows the other example of the support tool in one embodiment of this invention. It is a figure for showing a series of processes in one embodiment of the present invention. It is a figure for showing a series of processes in one embodiment of the present invention. It is a figure for showing a series of processes in one embodiment of the present invention. It is a figure for showing a series of processes in one embodiment of the present invention. (B) is an expanded sectional view of a portion B illustrated in (a). It is a figure for showing a series of processes in one embodiment of the present invention. It is a figure for showing a series of processes in one embodiment of the present invention. It is a figure which shows an example at the time of jacking down the tank main body in one Embodiment of this invention, (a) is before jackdown, (b) is a figure which shows after jackdown.

  Hereinafter, an embodiment according to a method for repairing an existing tank of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a diagram showing a tank 1 before repair in this embodiment, and FIG. 2A is a diagram showing a bottom plate 4 of the tank of this embodiment. As shown in FIG. 2A, the bottom plate of the present embodiment is configured with an annular bottom plate (annular plate) 4A on the outside, and the bottom plate 4B is disposed on the inside thereof.

  In the construction method of the present invention, as will be described in detail later, the side plate is supported directly below by a plurality of support tools at the lowest stage of the existing side plate of the tank. An installation place for installing such a support is provided. This installation place is provided with a plurality of openings over the entire circumference (entire in the circumferential direction) at a predetermined interval at the lowest stage of the existing side plate, and positions corresponding to the openings in the annular bottom plate are below the openings. It is provided by excision (see FIG. 3).

  FIG. 2B shows an example of a bottom plate different from the present embodiment in the case where the annular bottom plate is not provided and only the bottom plate 4B is provided. When a tank having such a bottom plate is to be repaired, the bottom plate is cut under each opening provided in the lowermost side plate. That is, the outer side (circumferential side) portion of the bottom plate (corresponding to the annular bottom plate in FIG. 2A), which is located below each opening provided in the lowermost side plate is cut out.

  The present invention enables the foundation work of the tank. The height H (see FIG. 3) of the opening 5 of the side plate is the height of the entire circumferential opening (see FIG. 6 and the like) provided in a later step. This all-around opening serves as an opening for carrying out the tank foundation work. Therefore, it is necessary that the height H of the opening 5 at the lowermost side of the side plate is such that foundation work can be performed. However, it is necessary to avoid that the tank support becomes unstable due to the entire circumferential opening being too wide. Considering the above, it is preferable that the height H of the opening 5 provided in the side plate is about 0.5 m to about 0.7 m.

  The width W of the opening 5 provided at the lowermost side plate is about 1 m. Therefore, each opening 5 has a width W of about 1 m × a height H of about 0.5 m to about 0.7 m, and this distance from the end of the opening 5 to the end of the adjacent opening 5 is about 4 m to about It is provided over the entire circumference at a pitch P of 5 m. The size and pitch of the openings 5 can be determined as appropriate based on conditions such as the size of the tank, but the height H of the openings 5 needs to be noted above.

  In the existing annular bottom plate 4A, the portions located under the openings 5 in the lowermost side plate (portions where support members described later) are cut off.

  As described above, an opening is provided at the lowermost stage of the side plate, and the existing annular bottom plate is cut away to provide a place for installing the support. FIG. 3 shows a state in which the lowermost stage of the side plate is opened, the corresponding portion of the existing annular bottom plate is cut out, and the installation place 6 for the support is provided. The order of excision of the lowermost side plate opening and the existing annular bottom plate is not necessarily limited, but it is preferable to excise the existing annular bottom plate after the lowermost side plate opening.

  It is preferable to attach a reinforcing tool to the second stage of the side plate before and after the process. As an example of the attachment of the reinforcing tool, for example, as shown in FIG. 3, the reinforcing ring 7 is attached to the inner surface of the tank.

  As shown in FIG. 4, the support tools 8 are respectively installed at the support tool installation locations 6 provided as described above. These support tools 8 support the side plates 2 and 3 by receiving the side plates 2 and 3 immediately below.

  The support is configured to support the side plate directly below. For example, as shown in FIG. 5A, it is assumed that an angle 9 and a camber 10 are used (see reference numeral 8A in FIG. 5A).

  As shown in FIG. 5B, the support tool may be a giraffe jack or the like (see reference numeral 8B in FIG. 5B). The giraffe jack is preferable in that the height can be easily adjusted.

  Note that the bottom iron plate 11, the bottom plate 12, and the like may be appropriately disposed under the horn or the giraffe jack.

  After attaching the support 8, the lowermost part of the lowermost side plate is cut off at the height H of the opening 5 (substantially coincides with the height of the support) and the lower end of the side plate is removed. Thereby, as shown in FIG. 6, an opening (entire circumferential opening) 13 is provided over the entire circumference in the lowermost portion.

  As a result, the tank 1 is supported in a natural posture without causing a moment on the side plate by the side plates 2 and 3 being supported by the support 8 immediately below.

  This eliminates the need for detailed and detailed strength calculations and the attachment and removal of a large number of reinforcing materials to cope with moments. In addition to avoiding the risk of damage to the side plate due to the attachment and removal of these reinforcing materials, etc., work required for basic maintenance necessary to support the hydraulic jack attached to the peripheral surface of the side plate Can be reduced. It is also possible to provide means for assisting tank support as desired.

  In the above state, the existing bottom plate including the annular bottom plate is cut, taken out from the opening over the entire circumference, and removed. FIG. 6 shows a state after the existing bottom plate is removed.

  Next, work for foundation correction (foundation work) will be carried out. For example, when there is unequal settlement, the correction is performed based on the lower part directly below the side plate.

  After the foundation work is completed, a new bottom plate including a new annular bottom plate will be laid. In addition, at the time of foundation construction and / or at the time of laying an annular bottom plate, the support 8 is replaced. FIG. 7 shows a state after the new bottom plate 14 is laid.

  Next, the lowermost side plate is replaced. As shown in FIG. 8, first, the bottom side plate is cut and removed (one opening 15 is provided for one side plate), and the opening horizontal portion (horizontal joint portion) 16 is grooved by a grinder or the like. .

  As shown in FIG. 9A, one new side plate 17 is inserted into the opening 15 for one side plate, and a fixing tool such as a strong back 18 is attached and fixed inside the side plate. Between the lowermost end of the new side plate 17 and the new annular bottom plate 14, as shown in FIG. 9B, it is preferable to insert a support member such as a gold arrow 19 and a liner plate 20 to support the tank. In this case, a fixing tool such as a guide piece 21 and a gold arrow 22 is attached and fixed to these supporting members inside and outside the side plate.

  Referring to FIG. 10, the existing side plate adjacent to the new side plate 17 inserted as described above is cut and removed by one piece in the same manner as described above, and one new side plate 24 is inserted into the opened portion and fixed. To do. The vertical joints between the new side plates are fixed using, for example, a fixture such as a strong back (curved) 23, and are subjected to temporary bonding by performing skin alignment. FIG. 10 shows a state after the new side plate 24 adjacent to the first new side plate 17 is inserted and fixed.

  By repeating the same procedure as above, the existing side plate is removed, the new side plate is inserted, and fixed one by one in order from the one adjacent to the new side plate, thereby replacing the lowermost existing side plate with the new side plate over the entire circumference. . Thereby, all the side plates to which the support tool is attached are updated. FIG. 11 shows a state where the lowermost side plate is replaced with a new side plate 25.

  When the gold arrow 19 and the liner plate 20 are inserted between the lowermost end of the new side plate and the new annular bottom plate, they are removed as follows and the tank body is lowered (see FIG. 12). First, a channel 27 for attaching a claw jack 26 or the like to be described later is attached to the inside of the new side plate 25 by welding over the entire circumference at intervals of about 3 m to 5 m. The guide piece 21 is removed as appropriate. Next, the claw jack 26 is attached to the channel 27, the jack is lowered while the gold arrow 19 and the liner plate 20 are pulled out, and the side plate is lowered.

  12 (a) and 12 (b) show a view when the channel 27 is welded to the inside of the new side plate 25, the claw jack 26 is attached to the channel 27, and the side plate is jacked down. FIG. 12A is a diagram before jackdown, and FIG. 12B is a diagram after jackdown. According to this method, the tank body can be lowered simply by jacking down using several claws jacks or the like while sequentially turning.

  After removing all the gold arrows and liner plates and jacking down the tank body, the new side plates are welded in sequence, including the vertical joint outer surface, horizontal joint outer surface, vertical joint inner surface, horizontal joint inner surface, and other necessary welding.

  According to the present invention, an annular bottom plate, other bottom plate, and foundation work can be performed by supporting the tank while maintaining the posture of the tank in a natural state directly below the side plate. Therefore, in order to ensure roundness by preventing the deformation of the side plate and the detailed strength calculation to cope with the moment generated in the side plate, which is necessary when refurbishing the existing tank, especially when using the jack-up method. It is not necessary to attach or remove many reinforcing materials.

  Moreover, the possibility that the side plate is damaged due to the attachment and removal of a large number of reinforcing materials and brackets can be greatly suppressed.

  Moreover, according to this invention, the operation | work etc. which are required for the foundation maintenance required in order to support the hydraulic jack etc. which are attached to a side-plate surrounding surface can be reduced.

  Furthermore, in the present invention, it is possible to cope with the side plate that has been attracting attention in recent years, particularly the modification at the bottom.

  Thus, according to the present invention, it is expected that maintenance of the existing tank becomes easier, and ensuring of the safety of the tank is promoted. Therefore, the industrial applicability of the present invention is extremely high.

DESCRIPTION OF SYMBOLS 1 Existing tank 2 Lower side plate 3 Side plate 2nd stage 4 Bottom plate 4A Annular bottom plate 5 Opening 6 Support installation place 7 Reinforcement rings 8, 8A, 8B Support
9 Shaft 10 Camber 11 Laying iron plate 12 Laying plate 13 Opening over the entire circumference
14 New bottom plate 15 Opening for one side plate 16 Open horizontal part (horizontal joint part)
17, 24, 25 New side plate 18 Fixing tool (strong back)
19 Support member (Kinya)
20 Support member (liner plate)
21 Fixing tool (guide piece)
22 Fixing tool (Kinya)
23 Fixture (Strong Back)
26 Claw jack 27 Channel

Claims (1)

(A) a step of providing a plurality of openings having a height of about 0.5 m to about 0.7 m at the lowermost part of the lowermost stage of the existing side plate of the existing tank, and cutting off portions of the existing bottom plate located below the openings;
(B) a step of installing a support for supporting the lowermost stage of the existing side plate in each opening;
(C) cutting the lowest part of the lowermost step of the existing side plate at the height of the opening, and providing an opening over the entire circumference in the lowermost part;
(D) cutting the existing bottom plate and removing it from the opening over the entire circumference;
(E) the process of performing foundation work,
(F) a step of carrying in and laying a new bottom plate from the opening over the entire circumference;
(G) a step of replacing the lowermost step of the existing side plate with a new side plate over the entire circumference;
A method for repairing an existing tank, characterized by comprising:

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