JP5127175B2 - Shape repair method for steel structures and steel products - Google Patents

Description

  For example, when a member such as a bridge, a steel tower, a storage tank, a sluice, a steel frame, or a construction machine such as a crane or a power shovel deteriorates due to corrosion or wear, the deteriorated part is restored to the original shape. The present invention relates to a method for repairing the shape of steel structures and steel products.

  Steel structures exist as structures in various fields, including public buildings, because of the superiority of steel materials such as workability, durability and economy. For example, steel structures are used not only for large buildings such as bridges but also for playground equipment in parks and amusement parks. These steel structures are surface protected by painting, etc., but deterioration of the coating due to aging occurs, and if proper maintenance management is neglected, corrosion of the steel progresses, reducing the thickness of the steel. In addition, the strength as the structure itself may not be able to maintain the desired value. For example, in a steel bridge, corrosion of an end cross girder is observed particularly due to breakage of an expansion / contraction device or leakage from a drainage device at the end portion, and corrosion of an attachment plate portion is observed in a bell plate of a box girder. Furthermore, if the repair is neglected, a cross-sectional defect occurs, the function as a structure is impaired, and there is a possibility that removal and reconstruction are required. For this reason, it is necessary to repair the deteriorated part and restore the strength and the like of the steel structure to an intended value to extend the life of the structure.

  For repairing a steel bridge of this type of steel structure, as described in Non-Patent Document 1, for example, a portion including a repaired portion that has deteriorated due to corrosion or the like and requires repair is cut into A repair replacement member with a matching shape is manufactured and fitted into the cut part, and connected to the repaired member from which the repaired part has been removed by welding, or the attachment member is spanned between the repair replacement member and the repaired member. It is made to join with a high strength bolt etc. Fig. 6 shows a schematic structure of a bridge girder 1 composed of a steel web 1a and a steel flange 1b as an example of a steel structure. A hatched portion shows a repair point 2 that needs to be repaired due to deterioration due to corrosion. Show. A part of the bridge girder 1 that is a repaired member including the repaired portion 2 is cut as a cut portion 3 as indicated by an imaginary line, and the cut portion 3 is melted and removed. On the other hand, as shown in FIG. 7, the repair replacement member 4 is manufactured in a factory or the like in substantially the same shape as the cut portion 3. The repair replacement member 4 is disposed on the portion where the cut portion 3 is removed as shown in FIG. 8 and joined to the bridge girder 1 by butt welding. Alternatively, as shown in FIG. 9, the high-strength bolt 6 is used to fasten the attachment member 5 between the repair replacement member 4 and the bridge girder 1.

  On the other hand, a step of spraying a granular material having a Mohs hardness of 7 or more onto the surface of a civil engineering building material made of metal to form a satin finish, and spraying aluminum and zinc on the surface treated to make the surface rich. A method for preventing rust and corrosion of civil engineering and building materials, which is a process for forming a room temperature drying type ceramic film as a pseudoalloy film, is disclosed (Patent Document 1). In addition, in the repainting repair of steel bridges, the deterioration balance of the steel bridge as a whole can be improved by applying a coating with higher weather resistance (durability) than the other parts to both ends of the steel bridge, where the degree of deterioration is significantly higher than other parts. A steel bridge coating method has been proposed that averages, extends the repainting repair cycle, and reduces maintenance costs (Patent Document 2). A method has been proposed in which this highly weather-resistant coating is obtained by room temperature metal spraying.

"Repair work for steel bridge" Mitsui Engineering & Shipbuilding Technical Report March 2004, published by Motoki Takayama, Hideo Nishitani Patent No. 2945384 JP 2006-144285 A

  In the above-described repair method, it is necessary to cut the gas around the correction point 2 and weld it. Therefore, it is necessary to carry gas and electric equipment to the site where the structure requiring repair is installed. In addition, since the melted surface becomes uneven, it is not possible to manufacture the repair replacement member 4 that matches the cut portion 3 as it is, and therefore it is necessary to process the melted surface smoothly to adjust the shape of the cut portion 3. . The dimension of the cut portion 3 with the trimmed shape is measured, a drawing for manufacturing the replacement member 4 for repair that matches the cut portion 3 is created, and the replacement member 4 for repair is manufactured based on the drawing. . The manufactured replacement member 4 for repair is brought into the field, and the replacement member 4 for repair is joined to the cut portion 3 by welding or by tightening the high-strength bolt 6 via the attachment member 5, so that the bridge girder 1 is restored. It will be restored to shape. At this time, in order to join the repair replacement member 4 by welding, the welding apparatus must be carried into the site. That is, the fusing work around the repaired part 2, the forming work of the cut part 3 after the fusing, the dimension measurement of the cut part 3, the production of the repair replacement member 4, and the joining work of the repair replacement member 4 to the cut part 3 Thus, a large number of processes are required, and the work process may become complicated. Moreover, in steel bridges, depending on the location, scale, etc. that require repair, there is a possibility that work must be performed while traffic is blocked.

  FIG. 10 is a perspective view showing an outline of the foundation of a road sign or road lamp post 7. The column 7 is erected on a base plate 8 on the upper surface of the foundation provided on the ground and reinforced by ribs 9. The structure is made. Since earth and sand and moisture are likely to accumulate in the joint portion between the pipe 7 and the rib 9 of the support column 7, the joint portion with the rib 9 is likely to deteriorate, for example, as shown by hatching in FIG. 10. When repairing the deteriorated portion 7a, the periphery of the rib 9 must be cut as a repair location, and the replacement member for repair must have a cylindrical shape that matches the column 7. The molding process of the repair / replacement member is complicated.

  Therefore, the present invention focuses on the technical contents of forming a metal film by spraying a metal material, and can easily restore a deteriorated portion due to corrosion or the like generated in various structures, particularly steel structures, to an original shape. It aims at providing the shape repair method of the steel structure and steel products to be made.

As a technical means for achieving the above object, the method for repairing the shape of a steel structure or a steel product according to the present invention is provided with respect to a case where an opening is formed due to deterioration caused by corrosion or the like occurring in the steel structure. In the method of repairing the shape of steel structures and steel products to extend the life of steel structures, a paper pad is pressed against one side of the repaired part, and high-frequency arc spraying is performed from the other side. Thermal spraying is performed by a low temperature spraying method to form a coating layer of a thermal spray material, and the repaired portion is restored to the original shape by closing the opening.

By forming a coating layer by metal spraying at the repair location, the repair location is restored to the original shape. In particular, when corrosion progresses, a hole is formed in the steel plate constituting the steel structure, and an opening may be formed. When the opening has a small diameter, it is repaired so as to match the cross-sectional shape of the steel sheet by pressing the contact plate and filling the opening with a thermal spray material. After the repair, the backing plate may be removed, and a material that can be easily discarded can be used.
In addition, the rust etc. which arise by corrosion by performing a blasting process etc. with respect to a repair location are processed suitably, and the surface is roughened and thermal spraying is performed. After construction, rust-proof coating is performed so that the appearance matches the steel structure that is the repaired member.
By the way, there are gas type and electric type in the thermal spraying method, there are flame spraying etc. as the gas type, and there are DC type thermal spraying, plasma thermal spraying, line explosion thermal spraying, high frequency arc thermal spraying, etc. In the invention, the coating layer is formed particularly by high frequency arc spraying. The high-frequency arc spraying is a spraying method suitable for forming the coating layer with a metal containing a component equivalent to the base material because it enables pseudo alloy spraying or galbarium composition spraying.
And in order to perform the construction by the high frequency arc spraying by the low temperature spraying method, the said board was made of paper. In addition, paper-made things, such as paperboard and corrugated paper, can be utilized.

  The shape repair method for steel structures and steel products according to the invention of claim 2 is characterized in that the thermal spray material is a metal containing a component equivalent to the base material.

  Since the metal equivalent to the base metal is used as the thermal spray material and the steel structure is repaired, a metal material whose composition component such as carbon is almost equal to the material of the steel structure, mainly steel, is sprayed. To do.

Further, in the method of repairing the shape of a steel structure or steel product according to the invention of claim 3 , spraying is performed by placing a filling member made of a material equivalent to a base material in the opening existing in the repaired portion. It is characterized by doing.

  When corrosion has progressed and the opened portion has become a wide range, the filling member is loosely inserted into the opening with the same steel material as that constituting the steel plate, and the gap between the filling member and the steel plate is increased. Thermal spraying is performed so that the thermal spray material is filled in the gap.

According to the method of repairing the shape of a steel structure or steel product according to the present invention, it is necessary to melt the repaired part, form the melted surface after fusing, measure the size of the cut part, and manufacture a repair replacement member to be incorporated into the cut part. Therefore, the repair work can be simplified and the repair cost can be reduced.
Moreover, since the thermal spray material can be filled into the opening by pressing the contact plate to the portion where the opening is formed, the opening can be closed and the repair work can be easily performed.
In addition, since it can be performed at room temperature by high-frequency arc spraying of the low temperature spraying method, the base material and the coating layer are not heated at the time of thermal spraying construction and are not affected by heat input. The desired strength can be secured by eliminating the influence.
In addition, since the patch plate can be easily removed after the repair construction by thermal spraying, the repair work can be simplified. In addition, since it is a backing plate made of an inexpensive material made of paper, the repair cost can be reduced.

  Further, according to the method for repairing the shape of a steel structure or steel product according to the invention of claim 2, in order to thermally spray a metal containing a component equivalent to the base material, when the steel structure is restored to the original shape by repair, The desired strength and the like can be provided.

In addition, according to the method for repairing the shape of a steel structure or steel product according to the invention of claim 3 , since the construction range of thermal spraying can be made as small as possible by interposing a filling member, it is possible to sufficiently ensure the goodness of construction. Can do.

  Hereinafter, based on the illustrated preferred embodiment, a method for repairing the shape of a steel structure or steel product according to the present invention will be specifically described.

FIG. 1 shows a schematic structure of a bridge girder 10 as a steel structure, which is formed of a steel web 10a and a steel flange 10b. A portion of the steel web 10b that is shaded is a corrected portion 11 that has deteriorated due to corrosion. A blasting process or the like is performed on the correction portion 11 to remove the rust on the surface to appropriately expose the base material and to prepare the surface roughly. As shown in the imaginary line in Fig. 2, the correction point 11 is sprayed with a metal containing almost the same components as the material of the bridge girder 10, that is, a metal composing a steel material equivalent to the steel material constituting the bridge girder 10. A coating layer 10c made of this thermal spray material is formed at the location 11. In addition, since the rust which has arisen in the repair location 11 is blown off by compressed air being sprayed by thermal spraying construction so that it may mention later, it is not necessary to perform the surface treatment of the correction location 11 completely by the said blasting process.

  The thermal spraying is preferably by high frequency arc spraying. FIG. 1 shows a state where a coating layer 10c is formed by high frequency arc spraying. In high-frequency arc spraying, compressed air is injected from a pair of air pipes 12 and intersected at an intersection C to discharge an arc from the tip of the wire rod 13 of the sprayed material. The arc converges on the wire 13 side from the intersection C. It is made to let you. For this reason, the arc receives suction force due to the flow of compressed air, is sucked and accelerated toward the intersection C, and is blown to the repair location 11. For this reason, the arc part is blown in a supercooled state by being locally decompressed. For this reason, the spraying temperature is close to 50 to 60 ° C. and normal temperature, and spraying can be applied to combustible materials such as paper and plastic.

  In a state where the coating layer 10c is formed by thermal spraying, the bridge girder 10 is almost restored to its original shape, and the coating layer 10c is subjected to rust prevention coating.

  FIG. 3 is a diagram showing a thermal spraying construction by another thermal spraying method, and shows the concept of jet air thermal spraying. In the jet air type thermal spraying, an arc is emitted from the tip of the wire rod 14, compressed air is blown through the air pipe 15 from the rear thereof, and the sprayed material is sprayed by a jet of the compressed air. In the repair method according to the present invention, a spraying method other than high-frequency arc spraying may be employed. For example, in high-frequency arc spraying, spraying within a reduced pressure is performed, and as shown in FIG. 1, the spraying range of compressed air greatly increases with the spraying distance, whereas in jet-air spraying, the spraying range is small. For this reason, jet-air spraying is suitable when repairing is performed by concentrating locally, and high-frequency arc spraying is suitable when the range of the repaired portion 11 is large.

  FIG. 4 shows a state in which a small-diameter opening 21a is bored in the repair location 21 due to the progress of corrosion or the like. When repairing is performed on the repaired part 21 in such a state, the spraying is performed by pressing the contact plate 22 against the side opposite to the spraying side while covering the opening 21a. By spraying, the opening 21a is filled with a thermal spray material, and a coating layer 10c is formed at the repaired portion 21, so that the repaired portion 21 is restored to the original shape that becomes a part of the bridge girder 10.

  After the thermal spraying, the abutting plate 22 may remain in a state of being left, but it can be removed. When the contact plate 22 is made of a steel plate or the like and remains, it needs to be fixed to the steel flange 10b with a bolt or the like. On the other hand, when spraying by high frequency arc spraying, the sprayed material is sprayed in a supercooled state, so it can be performed at room temperature, so use a flammable material such as paperboard, corrugated paper, plastic, etc. for the backing plate 22 You can also. This type of combustible material is preferable because it can be easily removed after repair work.

  As shown in FIG. 5, when the opening 31a formed in the repair location 31 is relatively large, a filler 32 as a filling member is loosely inserted into the opening 31a. Further, in a state where the opening 31a is covered, the contact plate 33 is pressed against the side opposite to the spraying side to perform spraying. The thermal spray material is filled in the gap between the filler 32 and the repair required part where the repair location 31 exists by thermal spraying, and the filler 32 is joined to the bridge girder 10 and the coating layer 10c of the thermal spray material is formed to repair the location. 31 is restored to its original shape. The backing plate 33 may be left, but when construction is performed by high-frequency arc spraying, a paper-made one can be used as described above, which is preferable because it can be easily removed after repair construction.

  When spraying is complete, apply anti-rust paint to complete the repair.

  In the above-described embodiment, the bridge girder 10 as a steel structure has been illustrated and described. However, any steel structure such as a road light post 7 or a playground equipment such as a park shown in FIG. The shape repair method of this invention can be implemented.

  According to the method for repairing the shape of a steel structure or steel product according to the present invention, repair work can be carried out by bringing the thermal spraying device into the repair site without requiring the work of fusing the correction points or the production of replacement parts for repair. Since it can be performed, quick repairs can be performed, and repairs can be performed in a timely manner by reducing the repair cost, thereby contributing to the extension of the life of the steel structure.

It is a figure which shows 1st Embodiment of this invention, and is a schematic perspective view explaining the case where the steel girder of a steel bridge is repaired, The case by high frequency arc spraying is shown. It is a front view of the repair location shown in FIG. 1, and has shown the coating layer by thermal spraying construction with the imaginary line. It is a figure explaining spraying methods other than high frequency arc spraying, and the outline in the case of repair by jet air type spraying is shown. It is a figure which shows 2nd Embodiment of this invention, and the case where a small diameter opening is formed in a repair location is shown. It is a figure which shows 3rd Embodiment which concerns on this invention, and shows the case where a big opening is formed in the repair location. It is a figure explaining the conventional repair method, and is a schematic perspective view which shows the state in which some bridge girders deteriorated. It is a figure explaining the conventional repair method, and is a perspective view which shows the replacement member for repair for replacing a repair location. It is a figure explaining the conventional repair method, and is a perspective view which shows the case where the replacement member for repair is joined to the repair location by welding. It is a figure explaining the conventional repair method, and is a perspective view which shows the case where the replacement member for repair is joined to a repair location via an attachment member. It is a figure explaining the state which the illumination pillar as a steel structure deteriorated, and is a schematic perspective view which shows the lower end part of a support | pillar.

Explanation of symbols

10 Bridge girder (steel structure)
10a steel web
10b steel flange
10c coating layer
11 Repair points
12 Air pipe
13 Wire
14 Wire
15 Air kite
21 Repair points
21a opening
22 Batting plate
31 Repair points
31a opening
32 Filling material
33 Batting plate

Claims (3)

In the method of repairing the shape of a steel structure or steel product for the purpose of extending the life of the steel structure, when an opening is formed due to deterioration due to corrosion or the like occurring in the steel structure,
Press a paper backing plate on one side of the repaired area, perform high-frequency arc spraying from the other side and perform thermal spraying using a low-temperature spraying method to form a coating layer of thermal spray material, and open the opening. A method for repairing the shape of a steel structure or steel product, characterized in that the repaired portion is restored to its original shape by closing.   The method for repairing the shape of a steel structure or steel product according to claim 1, wherein the thermal spray material is a metal containing a component equivalent to a base material.   The steel structure or the steel according to claim 1 or 2, wherein a filler member made of a material equivalent to a base material is disposed in the opening existing at the repair location to perform thermal spraying. Product shape repair method.

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