JP4031476B2 - How to paint steel bridge - Google Patents

Description

  The present invention relates to a method for painting a steel bridge, and more particularly, to a painting method for extending the repainting cycle of a steel bridge.

  Repainting of steel bridges for the maintenance and maintenance of steel bridges has been performed as a set for the entire steel bridge according to the principle of the same cycle and the same specifications. About the judgment of repainting time, the incidence rate of rust and peeling in the whole steel bridge is calculated, and it judges based on the degree. Specifically, the determination is based on the area of rust and paint peeling of the entire steel bridge as shown in Table 1 below, and when the area reaches a predetermined standard as shown in Table 2, repainting is required.

すなわち、鋼橋全体について錆の発生が１％を超えており（評価４）、且つ、剥がれの発生が、１％を超えている場合（評価３及び４）は、早い時期に塗り替え補修工事が必要となる。

In other words, if the occurrence of rust exceeds 1% for the entire steel bridge (Evaluation 4) and the occurrence of peeling exceeds 1% (Evaluation 3 and 4), repainting repair work will be performed at an early stage. Necessary.

  By the way, it is known that the progress of deterioration such as rust and peeling in the steel bridge is remarkably fast at both ends of the bridge (particularly in the vicinity of the abutment) as compared with other parts. Usually, even when it is determined that repainting is necessary based on Tables 1 and 2, the deteriorated portions where rust and peeling occur are mostly concentrated at both ends of the bridge.

  In other words, in the past, deterioration of both ends of the bridge has progressed based on the idea of repainting the entire steel bridge with the same specifications, but other parts have not necessarily deteriorated to the extent that repainting is necessary. Even if it exists, the whole steel bridge was repainted when the deterioration rate of the whole steel bridge exceeded the predetermined standard by deterioration of the both ends.

  Therefore, due to the significant deterioration concentrated on a small part of the steel bridge, the entire steel bridge needs to be repainted even though most parts of the steel bridge are in a healthy state that does not require repair, and the repaint cycle is compared. There is a problem that it becomes shorter.

  Moreover, although the repainting is necessary, the entire steel bridge has to be repainted, which increases the repainting cost. Therefore, in recent years, the repainting period seems to be delayed, and the number of aging steel bridges tends to increase. Therefore, the repair is an urgent issue for maintaining and maintaining the steel bridge safely and comfortably, and a low cost and long repainting coating method is required.

  Then, the objective of this invention is providing the coating method of the steel bridge which can extend a repainting period, suppressing a cost increase.

Coating method bridges of the present invention for achieving the above object, the coating method at the time of refinishing repair composed bridge main girder steel material, the end portion of the main beam in the longitudinal direction of the bridge, the main Ri by the main beam remaining painting sites excluding the ends in the length direction of the spar, repainted by the first coating method weatherability is high coating method, in the longitudinal direction of the concrete part of the bridge The end portion is coated so that the weather resistance is higher than the remaining portion of the concrete portion excluding the end portion in the length direction of the concrete portion, and the end of the main girder is repainted and the end of the concrete portion The coating of the main girder is performed at the same time, and only the end portion in the length direction of the main girder is repainted by the first painting method, and the remaining part of the main girder is not repainted at the same time. To do.

In the above and the coating method, the end in the length direction of the main girder has, for example, a first part on the abutment and a second part without an abutment below, and the length of the second part The length is substantially the same as or shorter than the length of the first portion. The first coating method is preferably coating by room temperature metal spraying.

End in the longitudinal direction of the front Symbol concrete portions, said bridges abutment has an end portion in the longitudinal direction of the deck of the bridge.

  According to the present invention, the steel bridge repainting cycle can be greatly extended. Contributes to reducing maintenance costs and life cycle costs.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention.

  In the present invention, a coating having a specification with higher weather resistance is applied to both ends of the steel bridge, which is rapidly deteriorated, as compared with the coating applied to other general parts. As a result, the progress of deterioration at both ends of the steel bridge slows down, and the progress of the deterioration of the entire steel bridge becomes slow, so the repainting cycle is extended. On the other hand, painting with a more weather-resistant specification is more expensive than the normal-specification coating, but it only applies to a small portion of the entire steel bridge, so the cost of repainting the entire steel bridge is slightly increased. It can be suppressed.

  FIG. 1 is a diagram for explaining a method of painting a steel bridge in an embodiment of the present invention. FIG. 1 shows a cross-sectional view of the end of a steel bridge. A main girder 3 is placed on the inner surface of an abutment (abut) 1 via a support 2, and further, an upper surface of the abutment 1 and a floor slab 5 are connected to each other via a telescopic device 4 to form a road surface.

  In the steel bridge, the part that must be painted is the steel main girder 3, and in this embodiment, the painting of the main girder 3 is made different at the end and other parts. That is, the end portion 3A of the main girder 3 is coated with a higher weather resistance than the coating applied to other portions. Preferably, a coating with higher weather resistance is applied to the support 2 as well.

  In the main girder end 3A, compared to other parts, deterioration promoting substances such as water droplets, snow melting agent and anti-freezing agent (calcium chloride) flowing down from the expansion / contraction device 4 remain and accumulate, and on the inner surface of the abutment 1 Moisture tends to be accumulated due to its presence. For this reason, the main girder end 3A is more rapidly deteriorated than other parts of the main girder 3, such as rust generation and paint peeling.

  Specifically, the main girder end portion 3A to which coating with higher weather resistance is applied refers to a portion having a predetermined length beyond the horizontal inner surface portion of the abutment 1 from the end of the main girder 3. That is, the main girder end portion 3A has a portion that is above the abutment 1 and a portion that does not have the abutment 1 below.

  The coating with higher weather resistance is applied to the part beyond the inner surface part of the abutment 1 (the part where the abutment 1 does not exist) because of the splashing and volatilization of water droplets and deterioration promoting substances from the inner surface of the abutment 1. It is because it adheres to this part and exists in the degradation environment similar to the inner surface upper part (part on the abutment 1) of the abutment 1.

  Drawing 2 is a mimetic diagram explaining the main girder edge part of a steel bridge. In FIG. 2, when the end part of the main girder 3 on the inner surface of the abutment 1 is about 1 meter, the main girder end 3A to which a coating having higher weather resistance is applied is a part on the abutment 1 ( The first part is 1 meter and the part without the abutment (second part) is about 1 meter, about 2 meters in total. The length of the portion without the abutment is preferably substantially the same as or shorter than the length of the portion on the abutment 1. However, the length of the main girder end 3A to which the coating having higher weather resistance is applied is not uniformly determined, and various environmental conditions in which the steel bridge is placed, the shape and length of the abutment, etc. It is decided in consideration of various factors.

  For example, assuming that the main girder end 3A, which is most deteriorated in a steel bridge with a total length of 100 meters, is 2 meters on one side, the main girder length and the area are in a proportional relationship. The occupying ratio is about 4%, and even if a coating having a higher cost than the general construction method is applied to this portion, the coating cost of the entire steel bridge is not greatly affected. On the other hand, by applying a coating with higher weather resistance to this 4% portion, the degree of occurrence of rust and peeling is significantly reduced, and the progress of deterioration is delayed. Therefore, the deterioration rate of the entire steel bridge due to secular change is reduced, and as a result, the repainting cycle based on the criterion based on Table 1 is lengthened, which contributes to cost reduction from the viewpoint of LCC (life cycle cost).

  Conventionally, without distinguishing between sites where corrosion / deterioration is fast and those where it is not, the deterioration rate of the steel bridge as a whole is determined according to the predetermined criteria as shown in Tables 1 and 2 above, and accordingly Since the repair plan was made, repainting the entire steel bridge was a major premise, and there was no idea of changing the type of painting for each part of the steel bridge. This has been emphasized that the entire steel bridge is uniformly repainted with the same specifications, and the present invention is completely different from such a conventional idea, and variation in the degree of progress of deterioration depending on the part. This is based on the viewpoint of reducing and averaging.

  According to the present embodiment, for example, during repainting repair, it is possible to perform repair by repainting only the end portion of the steel bridge having a high deterioration rate. If only the edge is repainted, the installation cost of the temporary scaffold is low, and the paint area is also very small, so even if you use a slightly expensive painting method, compared to the cost of repainting the entire steel bridge, It can be significantly reduced. On the other hand, the portions other than the end portions that are not repainted are originally less deteriorated and the deterioration rate is slower, so there is no problem in safety and strength even if the repaint cycle is extended. As a result, the coating cycle with higher weather resistance is applied only to the end portion, thereby extending the repainting cycle of the entire steel bridge, leading to a reduction in life cycle cost. Of course, at the time of repainting repair, the end portion may be repainted with high weather resistance and the other portion may be repainted with normal coating at the same time. Even in this case, the repainting cycle is extended and the life cycle cost is reduced.

  Here, a method for painting the main beam 3 will be briefly described. In the present embodiment, a coating having higher weather resistance than the coating applied to other parts is applied to the end 3A of the main girder 3, but the conventional general coating applied to other parts is, for example, According to “Handbook of Steel Road Painting” (June 1990) published by Japan Road Association. In this manual, various coating systems such as A coating system using phthalic acid, C-1 coating system using polyurethane, and C-3 coating system using fluorine are specified according to environmental conditions and application locations. ing. In addition, other organizations such as the Japan Highway Public Corporation have established coating standards as well, but these standards use higher quality (for example, higher weather resistance) coating technology than the coating systems of the established standards. It does not prevent it.

  In the present embodiment, the general portion excluding both end portions 3A of the main girder 3 is coated in accordance with various standards as before, and the both end portions 3A of the main girder 3 have higher weather resistance than that. Apply paint. As a coating means with higher weather resistance, for example, a metal spraying system is known.

  The metal spraying system is a technology that forms a coating film by melting a solid substance such as metal and spraying it on the surface of an object. In particular, steel bridges have recently become possible due to the development of compact construction machines and room temperature spraying technology that sprays pseudo-alloys (zinc (Zn) / aluminum (Al)), which have a high anticorrosion effect, at room temperature. It is also applicable to repainting. This room temperature metal spraying system is different from conventional metal spraying (frame spraying, arc spraying, plasma spraying) in that a special rough surface forming agent is applied as a pretreatment and the room temperature is applied to the adherend. The point that can be constructed by using a Zn-Al pseudo-alloy as a sprayed metal is mentioned, not only blocking the factors (oxygen, moisture, salinity) that steel materials corrode, but also taking advantage of the characteristics of zinc-aluminum pseudo-alloy. By making it difficult to generate rust in terms of potential, high-quality coating that is not affected by the shape or construction accuracy of the steel material can be realized. In addition to improving the rust prevention effect, there is little zinc fume and dust, workability is good, thermal spraying with the adherend and excellent adhesion between the metal, durability and weather resistance It is a very good coating system.

  In the embodiment of the present invention, it is preferable that the end portion 5A of the floor slab 5 and the abutment 1 which are concrete portions of the steel bridge may be subjected to weather resistance coating.

  As for concrete structures, deterioration such as cracking, damage, and peeling of concrete occurs due to neutralization of concrete and frost damage. And as for this deterioration phenomenon, it is known that the deterioration progress of the concrete part in the edge part of steel bridges, such as both ends 5A of the floor slab 5, will be faster than other parts like the steel main girder 3. . As with the reason for the deterioration of the end 3A of the main girder 3, water drops, deterioration promoting substances (snow melting agents, antifreezing agents, etc.) are likely to adhere, and moisture is likely to accumulate (in the case of the abutment 1, its inner surface). is there.

  Conventionally, the concrete part of the steel bridge has not been usually painted, but the deterioration of the concrete part is also faster at the edges than at other parts, as in the main girder. Therefore, the repair cycle can be extended by coating the concrete portion at the end of the steel bridge with high durability and weather resistance.

  FIG. 3 is a view when the end portion of the steel bridge is painted according to the embodiment of the present invention. Fig.3 (a) is the figure which looked at the steel bridge from diagonally lower side, FIG.3 (b) is the figure seen from diagonally upper side. As shown in the drawing, the end portion of the steel bridge including the main girder end portion 3A, the floor slab end portion 5A, the support 2 and the abutment 1 colored in gray is painted with high weather resistance.

  Conventionally, repainting of the main girder part and repair of the concrete part have been carried out separately, but as in this embodiment, a temporary scaffold installed when repainting both ends of the main girder of the steel bridge is used. It is possible to simultaneously repaint both ends of the concrete part of the steel bridge at the same time, reducing the cost and time for installing temporary scaffolding and dismantling work compared to working separately. Can reduce the maintenance cost of the entire steel bridge.

  As a countermeasure for preventing deterioration of the concrete portion, there is a method of protecting the concrete by covering the surface of the concrete with a highly durable organic coating film and blocking it from the base. Further, as a higher quality coating method, there is a method in which a permeable inorganic reactive modifier such as an alkali silicate aqueous solution is applied and infiltrated into concrete. According to this method, the concrete holes can be completely filled and made nonporous. Specifically, insoluble crystals (glass substances) are formed on the concrete surface and inside, preventing intrusion of rainwater and salt into the interior, and further improving strength, water resistance, dust resistance, wear resistance, etc. Can be made.

  In addition, about concrete part, painting may be given from the beginning, but in such a case, by carrying out painting that is higher in weather resistance than already applied paint on both ends of the concrete part, Similar effects can be obtained.

  As described above, in this embodiment, in repairing a steel bridge, the steel bridge is coated with higher weather resistance (durability) than the other parts at both ends of the steel bridge where the degree of deterioration is more remarkable than the other parts. We explained how to paint steel bridges that average the deterioration balance of the entire bridge, extend the repair (repainting) cycle, and reduce maintenance costs.

  Further, the present embodiment is not limited to repairing a steel bridge, but can be applied to a new construction of a steel bridge. That is, in the new construction of the steel bridge, the period until the next repair can be extended by making the coating of both ends more highly weather-resistant than the coating of other parts.

  In addition, the present embodiment is not limited to a steel bridge whose main girder is steel, and can be applied to other bridges such as a bridge whose main girder is made of concrete. Even in a bridge in which almost all of the main components including the main girder are made of concrete, as described above, the deterioration of the end portion of the concrete portion is faster than the other portions. Therefore, the end of the concrete part including the main girder is coated with a weather resistance higher than that of other parts, so that the bridge repainting cycle can be extended and the life cycle cost can be reduced.

It is a figure explaining the coating method of the steel bridge in embodiment of this invention. It is a schematic diagram explaining the main girder edge part of a steel bridge. It is a figure at the time of coating the edge part of the steel bridge by embodiment of this invention.

Explanation of symbols

1: abutment, 2: support, 3: main girder, 3A: main girder edge, 4: telescopic device, 5: floor slab, 5A: floor slab edge

Claims (4)

In the painting method at the time of repainting repair of the bridge whose main girder is made of steel ,
The end of the main girder in the longitudinal direction of the bridge, the main beam of Ri said Lord painting of the remaining sites of digits excluding the ends in the longitudinal direction, the first weather resistance is high coating method repainted by the method of painting,
The end portion in the length direction of the concrete portion of the bridge is coated so that the weather resistance is higher than the remaining portion of the concrete portion excluding the end portion in the length direction of the concrete portion,
Repainting the end of the main girder and painting the end of the concrete part at the same time, and repainting only the end in the length direction of the main girder by the first painting method, at the same time A method of painting a bridge , wherein the remaining part of the main girder is not repainted . In claim 1 ,
The end of the main girder in the length direction has a first part on the abutment and a second part without an abutment below, and the length of the second part is the first part A method for painting a bridge , characterized in that the length is substantially the same as or shorter than the length of the bridge . In claim 1 or 2 ,
The first coating method is a coating method of a bridge characterized in that the coating is performed by room temperature metal spraying. In any one of Claims 1 thru | or 3 ,
The end portion in the longitudinal direction of the concrete portions, said bridges abutment, bridge method painting, characterized in that it has an end portion in the longitudinal direction of the deck of the bridge.

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