JP5672195B2 - Steel chimney cylindrical steel skin repair method - Google Patents

Description

  The present invention relates to a method for repairing a cylindrical iron skin of a steel chimney, and is particularly suitable for attaching and reinforcing a reinforcing member on the outer peripheral surface of the cylindrical iron skin.

  The steel chimney has a refractory material attached to the inside, for example, to improve heat resistance, but may deteriorate due to long-term use. In the following Patent Document 1, a longitudinal rib along the circumferential direction and a lateral rib forming a cross beam are joined to the inner peripheral surface of the cylinder, and a carbon fiber wire is wound around the outer peripheral surface of the cylinder. In addition, reinforcing bars are joined to the longitudinal ribs, and mortar is filled between the longitudinal and lateral ribs to repair the cylinder.

JP 2006-291251 A

  For example, when repairing the thinned portion of the tubular iron skin, the widthwise end of a reinforcing member made of a plate material may be abutted against the tubular iron skin and fixed by welding. In such a case, since the chimney is an outdoor facility, in order to prevent so-called crevice corrosion, it is necessary to weld the butted portion of the reinforcing member all around. In particular, when a reinforcing member made of a plate material is welded and fixed longitudinally in the height direction of the chimney, the long butted portion of the reinforcing member is welded all around, which takes time and effort for the work.

  The present invention has been made paying attention to the above-described problems, and is a steel chimney capable of reducing the work of welding and fixing a reinforcing member made of a plate material to a tubular shell of a steel chimney. The object is to provide a method for repairing a tubular iron skin.

  In order to solve the above-mentioned problem, the steel chimney tubular iron skin repair method of the present invention is a method for repairing a steel chimney tubular iron skin, and includes a plate member width direction end portion of a reinforcing member made of a plate material. When repairing by welding and fixing to the outer peripheral surface of the cylindrical body skin, the length of the portion of the reinforcing member made of the plate material in contact with the cylindrical body skin at the end portion in the width direction of the plate material becomes a preset length. Thus, the plate member width direction end portion of the reinforcing member other than the contacting portion is intermittently escaped in advance by a predetermined length, and the plate member width direction of the reinforcing member is perpendicular to the outer peripheral surface of the cylindrical iron skin The plate member width direction end portion of the reinforcing member is brought into contact with the outer peripheral surface of the cylindrical body skin so that the cylindrical body skin contact portion at the end portion of the reinforcing member in the plate width direction is welded all around. It is a feature.

  Since the board | plate material which comprises the reinforcement member of this invention is a board | plate material, it has a board surface with a large area. The width direction of the plate material is a direction that defines the width of the plate material along the plate surface, and thus may be any direction as long as the direction is substantially along the plate surface. Further, “relief” means to prevent a predetermined portion at the end of the reinforcing member in the width direction of the plate member from coming into contact with the tubular iron skin, for example, by removing or bending.

Further, the length of the portion of the reinforcing member in the plate width direction end contacting the cylindrical iron skin is 40 to 150 mm, and the length of the portion of the reinforcing member in the plate width direction end that is preliminarily escaped is 80 to 600 mm. It is characterized by that.
Further, the plate member width direction end of the reinforcing member on the opposite side to the cylindrical iron skin contact side is bent so as to be perpendicular to the plate material width direction.

  Thus, according to the method of repairing a tubular chimney of a steel chimney according to the present invention, a plate material is repaired by fixing the plate member width direction end of a reinforcing member made of a plate material to the outer peripheral surface of the tubular iron skin. The plate member width direction end portion of the reinforcing member other than the contacting portion is set so that the length of the portion in contact with the cylindrical iron skin at the plate width direction end portion of the reinforcing member made of Plate material width direction of the reinforcing member on the outer peripheral surface of the cylindrical iron skin so that the plate member width direction of the reinforcing member is intermittently escaped in advance by a preset length and is perpendicular to the outer peripheral surface of the cylindrical iron skin Since the end portion is in contact and the cylindrical iron skin contact portion at the end of the reinforcing member in the plate width direction is welded all around, the end of the reinforcing member in the plate width direction of the reinforcing member is compared with the case where the end is not released. Work is reduced because the entire circumference weld length of the skin contact part is shortened, and the outer peripheral surface of the cylindrical iron skin is deformed. Or combined plate width direction end portions of the reinforcing member, also reduces adjustment work or to interposed the supplement member between the plate member widthwise end portions of the reinforcing member and the outer peripheral surface of the cylindrical body steel shell.

In addition, the length of the portion of the reinforcing member in the plate width direction end that contacts the cylindrical iron skin is 40 to 150 mm, and the length of the portion of the reinforcing member in the plate width direction end that is escaped in advance is 80 to 600 mm. Thus, it is possible to reduce the work while ensuring the welding strength.
In addition, the strength of the reinforcing member can be improved and the welding strength can be improved by bending the end of the reinforcing member in the plate width direction opposite to the cylindrical iron skin contact side so as to be perpendicular to the plate width direction. it can.

It is a whole front view showing one embodiment of the steel chimney to which the cylindrical iron skin repair method of the present invention is applied. It is a top enlarged front view of the steel chimney of FIG. FIG. 3 is a transverse cross-sectional view of a tubular iron skin of the steel chimney of FIG. It is explanatory drawing of the reinforcement member welded and fixed to the cylindrical iron skin of FIG. It is a perspective view of the reinforcement member of FIG. It is explanatory drawing of the adjustment operation | work of the contact part of the reinforcement member of FIG. It is explanatory drawing of the reinforcement member welded and fixed to the conventional cylindrical iron skin.

Next, an embodiment of the steel chimney tubular iron skin repair method of the present invention will be described with reference to the drawings.
FIG. 1 is an overall front view of a steel chimney to which a cylindrical iron skin repair method of this embodiment is applied. In this embodiment, two steel chimneys 1 are erected on the inside of one steel tower 2, one on the front is a large-diameter steel chimney 1, and the other on the back is a small-diameter steel chimney 1. It is. The cylindrical iron skin repair method of this embodiment demonstrates what was given to the large diameter steel chimney 1. FIG. By the way, this kind of steel chimney 1 is self-supporting, and the steel tower 2 supports the rolling and falling of the cylinder. Further, a refractory material such as an amorphous acid-resistant castable may be lined (lined) on the inner side of the iron skin covering the outer periphery of the cylinder.

  2 is an enlarged front view of the top of the steel chimney 1 of FIG. 1, and FIG. 3 is a cross-sectional view of FIG. In the present embodiment, the reinforcing member 4 made of a plate material is welded and fixed to the outer periphery of the top of the cylindrical iron shell 3 of the large-diameter steel chimney 1 for repair. The reinforcing members 4 are made of a plate material that is long in the height direction of the cylindrical iron skin 3, and are attached equally at a predetermined angle, for example, 22.5 ° in the circumferential direction. The reinforcing member 4 is welded and fixed to the outer peripheral surface of the cylindrical iron skin 3 so that the width direction of the plate material is perpendicular to the outer peripheral surface of the cylindrical iron skin 3.

  In FIG. 4, the detail of the welding fixation to the cylindrical iron skin 3 of the reinforcement member 4 is shown. In the present embodiment, the reinforcing member 4 other than the contacting portion is set so that the length of the portion of the reinforcing member 4 made of the plate material that contacts the cylindrical iron skin 3 at the end in the width direction of the plate material becomes a preset length. The plate material width direction end portion is intermittently escaped in advance by a preset length. FIG. 4a shows details of part A of FIG. 2, and FIG. 4b shows details of part B of FIG.

  2A shown in FIG. 4a, a cylindrical member 5 is attached to the outer peripheral surface of the cylindrical iron skin 3, and a disk-shaped cylindrical reinforcing member 6 is attached to the cylindrical member 5, and the disk-shaped A connecting member 7 is attached to the cylindrical reinforcing member 6. Among these, the cylindrical member 5 and the cylindrical reinforcing member 6 are for holding the circular cross section of the cylindrical iron skin 4. Further, the connecting member 7 abuts on the connecting member protruding from the steel tower 2, supports the rolling and falling of the cylinder as described above, and allows the chimney to expand and contract. A reinforcing member 4 is welded and fixed to the cylindrical iron skin 3 from below the cylindrical reinforcing member 6 in the longitudinal direction in the height direction of the cylindrical iron skin. Moreover, the joining part of the cylindrical member 5 or the cylindrical reinforcing member 6 and the reinforcing member 4 is also fixed by all-around welding. In addition, the width direction edge part on the opposite side to the cylindrical iron-skin welding fixed side of all the reinforcing members 4 is bent in the direction perpendicular to the paper surface of the drawing, and the strength is increased.

  2b shown in FIG. 4b, a disk-shaped tubular reinforcing member 8 is attached via a rib 10 so as to penetrate the tubular iron skin 3, and a protruding tip portion faces downward above the rib 10. A dust cover 9 is attached obliquely so that In this portion, the reinforcing member 4 is welded and fixed to the cylindrical iron skin 3 longitudinally in the height direction of the cylindrical iron skin 3 both above and below the cylindrical body reinforcing member 8. Further, the joint portion between the tubular reinforcing member 8 and the reinforcing member 4 is also fixed by all-around welding. The dust cover 9 is for preventing dust from accumulating on the disk-shaped cylindrical reinforcing member 8. This is because when dust accumulates on the disk-shaped cylindrical body reinforcing member 8, the accumulated dust contains moisture and wets and corrodes, so that the dust cover 9 prevents the dust from accumulating on the cylindrical body reinforcing member 8. ing.

  Although not shown in FIG. 2, as shown in FIG. 4 c, there is also a part where the reinforcing member 4 made of a plate curved in an arc shape is welded and fixed along the circumferential direction of the outer peripheral surface of the cylindrical iron skin 3. . In any case, the reinforcing member 4 other than the contacting part is set so that the length of the part in contact with the cylindrical iron skin 3 at the end in the width direction of the sheet material of the reinforcing member 4 made of a plate material becomes a preset length. The portion of the plate material width direction end is intermittently escaped in advance by a preset length. And only the contact part of the cylindrical iron skin 3 and the reinforcement member 4 is being fixed by the perimeter welding.

  Conventionally, for example, as shown in FIG. 7, when the reinforcing member 4 made of a plate material is welded and fixed to the outer peripheral surface of the cylindrical iron skin 3 in the longitudinal direction, the width of the reinforcing member 4 on the cylindrical iron skin contact side Since the direction end portion is not escaped, in order to prevent crevice corrosion, the entire length of the plate member length of the reinforcing member 4 must be welded. This takes too much time and time for welding, and also requires time and labor for adjusting the reinforcing member 4 and filling the gap in accordance with the deformation of the cylindrical iron shell 3 as will be described later.

  On the other hand, for example, as shown in FIG. 5a, the end in the width direction of the reinforcing member 4 made of a plate material on the cylindrical iron skin contact side is intermittently escaped in advance by a predetermined length, and only the cylindrical iron skin contact portion is entirely surrounded. If welding is performed, the labor and time of the welding itself can be reduced. Further, as shown in FIG. 6a, when the cylindrical iron skin 3 is deformed outwardly, the contact portion of the reinforcing member 4 is removed, and as shown in FIG. In the case of being deformed inwardly, adjustment work such as interposing the gap filling member 11 between the contact portion of the reinforcing member 4 and the cylindrical iron skin is required. Such adjustment work such as the processing of the reinforcing member 4 and the gap filling work is also greatly reduced as compared with the case where the end of the reinforcing member 4 in the width direction of the cylindrical iron skin contact side does not escape. In addition, when the strength of the reinforcing member 4 is sufficient even between flat plates, as shown in FIG. 5b, the end in the width direction opposite to the cylindrical body contact side of the reinforcing member 4 may not be bent.

  The length (hereinafter also referred to as the contact length) of the portion of the reinforcing member 4 made of the plate material that contacts the cylindrical iron skin 3 is L1, and the length of the portion that is escaped in advance (hereinafter also referred to as the escape length) is L2. Then, it is desirable that the contact length L1 of the portion in contact with the cylindrical iron skin is 40 to 150 mm, and it is desirable that the removal length of the portion removed in advance is 80 to 600 mm. Of these, the contact length L1 is preferably set to 40 mm or more with reference to the numerical values of the steel structure design standard, since both end portions of the welding start point and end point include defects. That is, according to the steel structure design standard established by the Architectural Institute of Japan, the effective length of fillet welding that transmits stress is 10 times or more of fillet and 40 mm or more, so the lower limit of the contact length L1 Was 40 mm. On the other hand, when the contact length L1 is increased, the adjustment work such as the processing work and the gap filling work accompanying the deformation of the cylindrical iron shell 3 as described above increases. Therefore, the upper limit value of the contact length L1 is set to 150 mm.

  Moreover, since the relief length L2 is intended to reduce the welding amount, the lower limit value is set to 80 mm with a reference of at least twice the contact length L1. On the other hand, considering the compressive buckling strength of the reinforcing member, for example, in the case of the reinforcing member 4 having a thickness of 15 mm and a width of 200 mm, the main member λ (elongation ratio) of the road bridge specification (issued by the Japan Road Association) < In order to make it 120, it is necessary to make the buckling length of the reinforcing member 4 600 mm or less. That is, since the relief length L2 needs to be 600 mm or less, the upper limit is set to 600 mm.

  As described above, in the method for repairing a steel chimney of a steel chimney according to the present embodiment, the plate material is repaired by fixing the plate member width direction end portion of the reinforcing member 4 made of a plate material to the outer peripheral surface of the cylindrical iron skin 3 by welding. The plate width direction of the reinforcing member 4 other than the contacting portion so that the length L1 of the portion in contact with the cylindrical iron skin 3 at the end portion of the reinforcing member 4 in the plate material width direction becomes the preset length L1. The outer periphery of the cylindrical iron skin 3 is such that the end portion is intermittently escaped in advance by a preset length L2 so that the plate member width direction of the reinforcing member 4 is perpendicular to the outer peripheral surface of the cylindrical iron skin 3. The end of the reinforcing member 4 in the width direction of the plate member is brought into contact with the surface of the reinforcing member 4 by abutting the cylindrical iron skin contact portion of the end of the reinforcing member 4 in the width direction of the plate member. Compared to not letting go through, the weld length of the entire circumference of the cylindrical iron skin contact part is shortened, reducing work. At the same time, the edge of the reinforcing member 4 in the width direction of the plate member is aligned with the deformation of the outer peripheral surface of the cylindrical iron skin 3, or the gap between the outer peripheral surface of the cylindrical iron shell 3 and the edge of the reinforcing member 4 in the plate material width direction is filled. Adjustment work for interposing the member 11 is also reduced.

Further, the length of the portion of the reinforcing member 4 in the width direction end of the plate member that contacts the cylindrical iron skin is 40 to 150 mm, and the length L1 of the portion of the reinforcing member 4 that is released in advance in the width direction of the plate member is 80 to 600 mm. By doing so, it is possible to reduce the work while ensuring the welding strength.
Moreover, the strength of the reinforcing member 4 is improved and the welding strength is also improved by bending the end of the reinforcing member 4 on the side opposite to the cylindrical iron skin contact side so as to be perpendicular to the plate width direction. be able to.

DESCRIPTION OF SYMBOLS 1 is a steel chimney 2 is a steel tower 3 is a cylindrical iron skin 4 is a reinforcing member 5 is a cylindrical member 6 and 8 is a cylindrical reinforcing member 9 is a dust cover 10 is a rib

Claims (3)

  A method for repairing a cylindrical iron skin of a steel chimney, wherein the reinforcing member made of the plate material is repaired by fixing the end portion in the width direction of the plate material reinforcing member to the outer peripheral surface of the cylindrical iron skin. The portion of the reinforcing member in the width direction of the reinforcing member other than the contacting portion is set in advance so that the length of the portion in contact with the cylindrical iron skin at the end of the width direction of the plate material is set in advance. The plate member width direction end of the reinforcing member is provided on the outer peripheral surface of the cylindrical iron skin so that the plate member width direction of the reinforcing member is intermittently escaped in advance by the length, and is perpendicular to the outer peripheral surface of the cylindrical iron skin. A method for repairing a cylindrical steel skin of a steel chimney, wherein the cylindrical steel skin contact portion at the end in the plate width direction of the reinforcing member is welded around the entire circumference.   The length of the portion of the reinforcing member in contact with the cylindrical iron skin at the end in the width direction of the plate member is 40 to 150 mm, and the length of the portion of the reinforcing member in the width direction of the plate member that is escaped in advance is 80 to 600 mm. The method of repairing a tubular iron skin of a steel chimney according to claim 1.   3. The steel chimney cylinder according to claim 1, wherein an end of the reinforcing member on the side opposite to the cylindrical iron skin contact side is bent so as to be perpendicular to the plate width direction. Iron skin repair method.

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