JP4530154B2 - Corner joint structure of pier and corner joint construction method - Google Patents

Description

  The present invention relates to a corner joint structure and a corner joint construction method for a pier, and more particularly to a technique for manufacturing a steel pier by constructing a corner joint by joining edges of thick steel plates by welding.

Various materials such as concrete materials are considered as piers for bridges and elevated roads, and one of them is a steel pier.
Steel piers are generally manufactured so as to form square joints by joining the edges of thick steel plates by welding to form a closed cross-sectional structure with a rectangular cross section (for example, a quadrangle).
When welding the edges of thick steel plates to form a corner joint, arc welding (SAW, SMAW, GMAW, etc.) is frequently used for reasons such as easy welding.

  By the way, when arc welding is used for the corner joint in this way, it is common to form a groove on the edge of one of the thick steel plates and form a weld metal bank on the widened portion of the groove. And when forming the said groove | channel, since arc welding cannot be performed about a root | route part, the part which is not welded partially (dissolved part) arises, and a corner joint turns into a partial penetration joint. However, even in such a partially-penetrated joint, it is necessary to ensure rigidity and strength for the corner joint part. As a result of research, the dimension in the plate thickness direction of the route part is, for example, the plate thickness of a thick steel plate. It is known that the size of the expanded portion should be sufficiently ensured by 1/4 or less (see Non-Patent Document 1).

On the other hand, recently, laser welding (LBW), in which a metal member is heated and melted with a laser beam to perform welding, has been developed and put into practical use. For example, laser welding is applied to a Y-shaped groove of a metal member together with arc welding. Such a welding method is known (Patent Document 1).
72nd Annual Meeting of the Japan Welding Society Annual Meeting PP250-251 “Study on the strength of corner joints in steel structures that allow plasticization” (issued March 24, 2003) JP-A-6-114587

  By the way, in arc welding, as shown in Non-Patent Document 1 above, when the dimension of the root part in the thickness direction is ¼ or less of the board thickness and the dimension of the expanded part is sufficiently secured, especially the corners. When trying to make the joint a fully-penetrated joint, the rigidity and strength of the corner joint part are ensured, but the amount of welding work is increased, the cost is increased, and the groove expanding portion is enlarged. Therefore, there is a problem in that the amount of weld metal increases, thereby increasing the amount of thermal shrinkage and increasing the residual stress, or increasing thermal deformation due to excessive heat input.

Furthermore, in the case where the corner joint is constituted by a partially-penetrated joint in which an unmelted portion is generated, there is a problem that sufficient seismic performance cannot be ensured even though a normal load can be supported.
On the other hand, the welding method disclosed in Patent Document 1 is such that laser welding and arc welding are applied to the butt joint of the plate members. Specifically, in the welding method disclosed in Patent Document 1, laser welding is performed from the root side (back side) of the plate member for the root portion of the Y-shaped groove, and the plate member is expanded for the spread portion. Arc welding is performed from the open side (front side).

However, in the above-described angular joint of a steel bridge pier, the welding method disclosed in Patent Document 1 cannot be applied as it is because the welding site is not simple butted welding.
Moreover, the technique disclosed in Patent Document 1 is mainly intended to improve the shape accuracy, and does not solve the above problem.

  The present invention has been made in order to solve such problems, and the purpose of the present invention is to provide high earthquake resistance while suppressing residual stress and thermal deformation, saving labor in welding work, and reducing welding materials. It is an object of the present invention to provide a corner joint structure and a corner joint construction method for a bridge pier capable of ensuring the above.

In order to achieve the above-described object, the corner joint structure of a bridge pier according to claim 1 is configured by welding an end face of one thick steel plate to an edge side surface of the other thick steel plate among adjacent thick steel plates. A corner joint structure of a bridge pier, wherein a groove formed of a pair of a L-shape or a J-shape groove is formed on an end face of the one thick steel plate to expand outward and inward of the pier , Laser welding is applied to the root portion of the groove, and arc welding is applied to the expanded portion and a weld metal is loaded.

  In other words, when trying to make a pier corner joint made by welding thick steel plates into a fully-penetrated joint, arc welding alone increases the amount of weld metal used due to an increase in the widened portion of the groove. Large residual stress is generated in the steel plate due to heat shrinkage of the metal, or the steel plate is thermally deformed due to increased heat input, but the root part of the groove is welded by laser welding. Thus, the usage amount of the weld metal is suppressed to the necessary minimum, the occurrence of residual stress is suppressed, the heat input is reduced, and the thermal deformation of the thick steel plate is suppressed. As a result, a complete penetration joint can be easily realized without increasing the expanding portion of the groove or increasing the heat input, and the rigidity and strength of the corner joint are ensured.

Further, in the plate thickness of the thick steel plates are thick as it expanded portion of the GMA is minimized by distributing the groove, thermal deformation of the generation and thick steel plates of residual stress due to arc welding satisfactorily suppressed Is done.

The setting, the corner joint structure of claim 2 piers, Oite to claim 1, wherein the thick plate steel plate thickness dimension is larger than 1/4 of the plate thickness of the thick steel plates of the root portion It is characterized by being.
That is, as described above, when arc welding is used for a corner joint, the dimension in the thickness direction of the root portion is, for example, ¼ or less of the plate thickness of the thick steel plate in order to ensure rigidity and strength for the corner joint portion. In other words, if the dimension in the thickness direction of the root portion is larger than 1/4 of the thickness of the thick steel plate, for example, there is a high possibility that sufficient rigidity and strength cannot be secured in the corner joint portion. However, even if the dimension in the thickness direction of the root part is larger than 1/4 of the thickness of the steel plate, a perfect penetration joint is realized by applying laser welding to the root part. The rigidity and strength of the part are ensured. Furthermore, in this case, the distance for laser welding is increased while the range of arc welding is reduced, generating residual stress due to arc welding and thermal deformation of thick steel plates. Is suitably suppressed

In the corner joint construction method of the pier of Claim 3 , the corner joint construction method of the pier comprised by welding the end surface of one thick steel plate to the edge side surface of the other thick steel plate among adjacent thick steel plates. The first step of forming a groove on the end face of the one thick steel plate, the second step of applying laser welding to the root portion of the groove, and after performing the second step, And a third step of performing arc welding on the expanded portion and loading the weld metal.

  In other words, when trying to make a pier corner joint made by welding thick steel plates into a fully-penetrated joint, arc welding alone increases the amount of weld metal used due to an increase in the widened portion of the groove. A large residual stress is generated in the steel plate due to heat shrinkage of the metal, or the steel plate is thermally deformed due to an increase in heat input, but a groove is formed on the end surface of one steel plate. By forming (first step), applying laser welding to the root portion of the groove (second step), and then applying arc welding to the expanded portion and loading the weld metal (third step), The amount of weld metal used is reduced to the minimum necessary, the occurrence of residual stress is suppressed, the heat input is reduced, the thermal deformation of the thick steel plate is suppressed, and the welded portion is not increased or increased. A fully-penetrated joint can be easily realized without increasing heat.

  According to the corner joint structure of the bridge pier of claim 1, the root portion of the groove is welded by laser welding, and the expanded portion is welded by arc welding, so that the amount of weld metal used can be kept to the minimum necessary and remains. Suppresses the generation of stress, suppresses thermal deformation of thick steel plates, and is constructed by welding thick steel plates without increasing the widened portion of the groove or increasing the heat input. Full penetration joints can be easily realized in the corner joints of piers.

As a result, the rigidity and strength of the corner joint can be ensured while saving the welding work and reducing the welding material, and a bridge pier having high seismic performance can be realized.
Further, in case that the thickness of the thick steel plates are thicker, can minimize the expanding portion of GMA by distributing the groove, favorably suppress heat deformation of the generation and thick steel plates of residual stress due to arc welding can do.

Also, according to the corner joint structure of the pier of claim 2, also the plate thickness dimension of the root part in a case where it is larger than 1/4 of the thickness of the thick steel plate, the laser welding to the root portion By constructing it, it is possible to realize a fully-penetrated joint and ensure the rigidity and strength of the corner joint part.In this case, further, the arc welding construction range is narrowed to generate residual stress due to arc welding and the thick steel plate Thermal deformation can be suitably suppressed.

According to the corner joint method of a bridge pier according to claim 3 , the groove root portion is welded by laser welding, and then the widened portion is welded by arc welding, thereby minimizing the amount of weld metal used. It is possible to suppress the occurrence of residual stress and suppress thermal deformation of the thick steel plate, and it is constructed by welding the thick steel plate without increasing the widened part of the groove or increasing the heat input. A perfect penetration joint can be easily realized in the corner joint of the pier.

  Thereby, it is possible to realize a bridge pier having high seismic performance while reducing the welding work and reducing the welding material.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a steel pier to which a corner joint structure according to the present invention is applied, and FIG. 2 shows a cross-sectional view of the pier along the line AA in FIG. Description will be made based on these drawings.
As shown in FIG. 1, a steel pier 1 is a pier that supports, for example, an elevated road and has a T shape from an arm portion 2 and a leg portion 4, and ends of a plurality of thick steel plates 10. It is configured as a structure with a closed cross-section structure by joining together by welding.

Here, the thick steel plate 10 is, for example, a flat plate having a uniform predetermined plate thickness t1 (for example, 25 mm to 60 mm).
As shown in FIG. 2, in the leg portion 4, the adjacent thick steel plates 10 a to 10 d are welded to each other by laser welding and arc welding at the end edges over the entire length of the corner joint to form a weld metal stack 40. . Thereby, a closed cross-sectional structure having a rectangular cross section is formed in the leg portion 4.

Referring to FIG. 3, a manufacturing process of the pier 1 for welding the thick steel plates 10 to each other is illustrated, and the corner joint construction method of the pier will be described in detail below based on the same drawing. Here, as an example, the thick steel plates 10a and 10b will be described as an example.
First, the end face 20 of the thick steel plate 10a is mold opening destination 22 is formed for the arc welding (first step).

That is, mold opening destination 22, as shown enlarged in FIG. 4, the central portion of the inner plate thickness direction of the end face 20 is chamfered so as to leave a root portion 24.
Specifically, since laser welding is performed on the route portion 24 as described later, the dimension L in the plate thickness direction of the route portion 24 is, for example, the maximum value at which laser welding can be performed in the plate thickness direction, that is, laser welding. It is set to the dimension corresponding to the ability.

  By the way, when only arc welding is applied to the corner joint, as described above, the dimension L in the thickness direction of the root portion 24 that is unwelded is set to, for example, 1/4 (t1) of the thickness t1 of the thick steel plate 10. / 4) It is known that it is preferable to make the following or less. In other words, the dimension L in the thickness direction of the root portion 24 that is unwelded is, for example, less than ¼ of the thickness t1 of the thick steel plate 10. When it is large, it is known that there is a high possibility that sufficient rigidity and strength cannot be secured in the corner joint portion.

However, when laser welding is performed on the root portion 24 as in the present application, there is no reason to suppress the dimension L to ¼ or less of the plate thickness t1, and conversely, if the laser welding is within the range of the laser welding capability. It is possible to make the dimension L larger than 1/4 of the plate thickness t1.
Therefore, more specifically, the dimension L in the thickness direction of the root portion 24 is set to a dimension larger than 1/4 of the thickness t1 of the thick steel sheet 10 within the range of the laser welding capability, for example.

Then, the root portion 24 of the thick steel plate 10a is brought into contact with the edge side surface 30 of the thick steel plate 10b, and laser welding is first applied to the root portion 24. Specifically, in a state where the root portion 24 is in contact with the other edge side surface 30 of the thick steel plate 10b, a laser beam R such as a YAG laser or a CO ₂ laser is applied to the outside of the pier 1 by the laser welding machine 50, that is, the expansion. Irradiation from the open portion 26 side toward the route portion 24 is performed. Thereby, the route part 24 is welded to the edge side surface 30 of the thick steel plate 10b.

When the root portion 24 of the thick steel plate 10a is welded to the edge side surface 30 of the thick steel plates 10b by laser welding, the weld metal rod 42 into the expanding portion 26, 28 of les mold opening destination 22 is inserted, an arc discharge Arc welding is carried out in a work of several passes while the weld metal melted by melting the thick steel plates 10a, 10b at the periphery (third step).
Thus, as shown in an enlarged weld 5, together with the root portion 24 of les mold opening destination 22 is welded to the thick steel plate 10b by laser welding, the arc welding, is expanded sections 26 and 28 The welded metal plate 40 is formed by welding the thick steel plate 10b and loading the weld metal into the expanded portions 26 and 28, respectively.

Hereinafter, the operation and effect of the corner joint structure and the corner joint construction method according to the present invention manufactured as described above will be described. Here, as an example, the thick steel plates 10a and 10b will be described as an example.
If it is going to realize a complete penetration joint only by arc welding to the corner joint of the pier 1, it is necessary to increase the expanded parts 26 and 28 or to weld to the root part 24, so that the arc discharge is strengthened. Required. As a result, the amount of weld metal used is increased, and a large residual stress is generated in the thick steel plates 10a and 10b due to thermal shrinkage of the weld metal, or the heat input is increased, so that the thick steel plates 10a and 10b are heated. Or deform.

  However, as described above, when the root portion 24 of the thick steel plate 10a is welded to the thick steel plate 10b by laser welding, there is no need to increase the expanded portions 26 and 28, and conversely, the plate of the root portion 24 The dimension in the thickness direction is larger than ¼ of the thickness t1 of the thick steel sheet 10 and is set to a dimension corresponding to, for example, the ability of laser welding. The welding range of arc welding, that is, the expanded portions 26 and 28 can be reduced while the welding operation can be reduced to about several passes as described above, and the amount of weld metal used can be minimized. The amount of heat shrinkage of the weld metal can be reduced, and the occurrence of residual stress in the thick steel plates 10a and 10b can be suppressed. Further, arc welding can be performed only in the range of the expanded portions 26 and 28, and it is not necessary to perform arc welding up to the root portion 24. Therefore, it is possible to complete the arc welding without making the arc discharge so strong. Yes, it is possible to reduce heat input and suppress thermal deformation of the thick steel plates 10a and 10b.

That is, the root portion 24 of the thick steel plate 10a is welded to the thick steel plate 10b by laser welding, and then the expanded portions 26 and 28 are welded by arc welding without increasing the expanded portions 26 and 28. Alternatively, a complete penetration joint can be easily realized without increasing heat input, and the rigidity and strength of the corner joint can be ensured.
As a result, it is possible to realize a bridge pier having high seismic performance while saving labor and reducing welding materials and reducing costs. Moreover, since the groove | channel formed in the end surface 20 of the thick steel plate 10a is provided in the outward side and the inward side of the pier 1 , for example, when the plate | board thickness of the thick steel plate 10a is thick, a groove part is set. The groove portions 26 and 28 can be distributed, and the groove portions 26 and 28 can be made as small as possible. Residual stress generated in the thick steel plates 10a and 10b by arc welding and thermal deformation of the thick steel plates 10a and 10b. Can be suppressed satisfactorily.

Note that although so as to form a Les mold opening destination 22 to the end face 20 of the thick steel plates 10a, may be formed a J-type GMA.

Although the description of the embodiment according to the present invention is finished above, the embodiment is not limited to the above, and various modifications can be made without departing from the spirit of the invention.
For example, in the above-described embodiment, the case where the corner joint structure of the pier according to the present invention is applied to the corner joint of the leg portion 4 has been described as an example, but the present invention is naturally applicable to a corner joint or the like of the arm portion 2. It is.

It is a figure which shows the steel pier to which the corner joint structure which concerns on this invention is applied. It is sectional drawing of the pier along the AA line of FIG. It is a figure which shows the manufacturing process of an pier. It is an enlarged view of a lathe groove. It is an enlarged view of a welding part .

Explanation of symbols

1 pier 2 arms 4 leg portion 10 thick steel 10a~10d thick steel plate 20 end face 22 bevel groove destination 24 root portion 26 expanding portion 28 expanding portion 30 end edge sides 40 weld metal overlay 42 weld metal rod 50 Laser Welding machine

Claims (3)

The corner joint structure of the pier constructed by welding the end face of one thick steel plate to the edge side surface of the other thick steel plate among adjacent thick steel plates,
A groove formed of a pair of a ladle or a J-shaped groove is formed on the end surface of the one thick steel plate to expand outward and inward of the pier .
A corner joint structure of a bridge pier, in which laser welding is applied to the root portion of the groove and arc welding is applied to the expanded portion and a weld metal is loaded. Wherein the thickness dimension of the thick steel plates of the root portion is set larger than 1/4 of the plate thickness of the thick steel plates, the corner joint structure of the pier of claim 1 Symbol placement . The corner joint construction method of the pier constructed by welding the end face of one thick steel plate to the edge side surface of the other thick steel plate among adjacent thick steel plates,
A first step of forming a groove formed of a pair of a ladle or a J-shaped groove that expands on the outer side and the inner side of the pier on the end face of the one thick steel plate;
A second step of performing laser welding on the root portion of the groove;
After performing the second step, a third step of performing arc welding on the expanded portion of the groove and loading a weld metal;
A corner joint construction method for a pier characterized by comprising:

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