JP2008000760A - Method of forming welded joint structure capable of reducing fatigue damage, and reinforcing resin block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a fatigue damage-reducing welded joint structure which can improve the fatigue strength of a fillet welding portion in the joint structure of metal materials, and also to provide a reinforcing resin block usable therefor. <P>SOLUTION: Firstly, the reinforcing resin blocks 11, 12 and 13 are prepared. Each of them has two flat surfaces perpendicular to each other so as to abut on the planes sandwiching a weld joint part for fixing a vertical stiffening material to a steel floor plate and has a brace body which connects the two flat surfaces and has the thickness gradually reducing toward the surface. Three faces of area in which the vertical stiffening material contacts the steel floor plate and the area of a prescribed width from the weld joint part on the steel floor plate are roughened and coated with an adhesive. Then, the reinforcing resin blocks are pressed on the adhesive and cured to form the reinforced structure of the weld joint of both steel floor plate and vertical stiffening material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a fatigue-reducing welded joint structure forming method for improving the fatigue strength of a fillet joint portion of a metal material and a reinforced resin block used therefor, and particularly to a steel floor of a road with heavy traffic such as a highway. The present invention relates to a welded joint structure forming method for reducing fatigue at a welded portion of a vertical stiffener in a plate and a reinforcing resin block.

  A joint structure using fillet welding is widely used for manufacturing structures using metal materials such as steel and aluminum alloys. However, in joint structures that are joined by fillet welding, if tensile stress or bending stress is applied to the base metal, stress concentrates on the toe of the fillet weld, so that repeated cracking causes fatigue cracks in the weld toe. And the fatigue strength of the welded portion is significantly lower than that of the base material. For this reason, the fatigue strength of the entire structure is dominated by the welded joint, and the characteristics of the base material cannot be fully utilized.

  For example, the elevated part of an expressway uses a steel slab structure in which a trough reinforced deck plate is supported by a main girder and a vertical stiffener is fixed to the deck plate bottom and main girder by fillet welding. Yes. In such a steel slab structure, fatigue cracks may occur in the vicinity of the welded portion of the deck plate and the vertical stiffener as the service period becomes longer, which may lead to serious damage.

  In order to improve the fatigue strength of the welded part, it is only necessary to increase the thickness of the base metal to reduce the distortion of the base material against stress and to reduce the stress applied to the weld toe, but the overall structure design A base material that is much stronger than the strength must be used, which is undesirable because it is a very uneconomical material design.

  Therefore, conventionally, the weld toe is cut and ground with a grinder or the like, or remelted with TIG or plasma to rework the toe smoothly to reduce stress concentration on the toe, The fatigue strength was improved. However, since these methods require careful processing of the vicinity of the toe portion of the weld metal after the structure is formed, a great amount of labor and labor are required, and the cost load is high.

  Patent Literature 1 discloses a method for improving weld fatigue strength as shown in the sectional view of FIG. The disclosed invention is a welded joint in which the main plate 100 and the rib plate 101 are joined by fillet welding, and the elastic modulus is 5% to 150% and (elastic modulus) × (thickness) is 1% to the base material 100. 50% of fiber reinforced plastic (FRP) 102 is fixed to the base material 100 and the fillet weld 101 so as to cover the weld toe 103 of the fillet weld 104, and one of the stresses applied to the weld toe 103. The stress concentration is reduced by sharing the part with the action of FRP.

  By this method, the stress concentration at the weld toe can be relaxed and the fatigue strength of the fillet welded joint can be improved. However, the disclosed invention is a technique invented by paying attention only to the stress concentration at the weld toe portion, and does not take into consideration the stress state of the entire welded portion, and thus has a limited effect. Moreover, only by attaching thin FRP, the stress sharing effect is small and the stress concentration reducing effect is also small.

The inventors of the present application have already applied fillet welding of the main plate 105 and the rib plate 106 and covered the welded portion 107 as shown in the perspective view of FIG. 17 according to the specification of Japanese Patent Application No. 2005-263129. A fatigue-reducing welded joint structure that relaxes stress concentration by forming a putty layer 108 fixed to 106 is disclosed.
According to the disclosed fatigue reduction type welded joint structure, the stress direction concentrated on the toe part of fillet weld is distributed to the putty layer side to relieve stress concentration, and the stress applied to the fillet weld part in the past The putty layer shares a part of this, and the fatigue strength of the welded joint can be improved by reducing the stress flowing through the fillet weld.

In addition, the disclosed welded joint structure can be easily constructed using simple tools, especially when applied to an existing structure or when on-site construction is required. Compared to other construction methods such as prime welding, there are significant advantages.
When applying the putty layer 104, first, the surface of the weld metal 103 is wiped with acetone and degreased. Subsequently, a putty material in which the main agent and the curing agent are kneaded is placed on the weld metal 103. After that, as shown in FIG. 18, a cylindrical mold 109 having a desired radius of curvature is pressed against the putty material and fixed for 24 hours, and then the mold is removed and completed. The mold material 109 is made by attaching a fluororesin sheet 110 to the surface of the wood part 111 so that the mold material can be easily released after the adhesive is cured.

However, in the disclosed welded joint structure, a putty layer is placed on the applied welded portion, the mold material is pressed and cured, and then the mold material is removed and completed. Therefore, not only the work efficiency is greatly affected by the situation at the site, but also the work for construction takes a long time and the influence on the construction at the site is also great. Furthermore, the appearance of the finished product depends on the situation in the field and the skill of the operator, and it is difficult to obtain a uniform quality.
JP-A-8-243778

  The problem to be solved by the present invention is to provide a method of forming a fatigue-reducing weld joint structure capable of improving the fatigue strength of a fillet weld in a joint structure of a metal material, and a reinforced resin block that can be used therefor In particular, it is to provide a reinforced resin block used for reinforcing a vertical stiffener in a steel deck such as an expressway.

  In order to solve the above-mentioned problems, the steel plate slab vertical stiffener reinforcement method of the present invention includes two planes that are perpendicular to each other and are in contact with a surface sandwiching a welded joint portion that fixes the steel plate and the vertical stiffener. A reinforcing resin block having a beam of a shape that connects between the planes and gradually decreases in thickness toward the plane is prepared, and each of the three surfaces in contact with the steel stiffener plate of the vertical stiffener and the welded joint portion in the steel deck The reinforcing structure of the steel floor slab vertical stiffener welded joint is formed by roughening the area from to the specified width, applying the adhesive, and pressing the reinforcing resin block on it to cure the adhesive. It is characterized by.

When a reinforcing structure is formed using the method of the present invention, the use of a ready-made reinforced resin block simplifies the work at the site, saving labor for skilled workers and reducing labor costs, and to other field work. The efficiency of construction will be improved.
In addition, in the reinforcing structure formed by the method of the present invention, the high stress concentration generated in the welded part where the steel plates are butt welded is dispersed and relieved in the reinforcing resin block, thus extending the life of the structure and maintaining, remodeling, and refurbishing. Can save you money.

  Further, in order to solve the above problems, the reinforcing resin block of the present invention is applied to a welded joint structure in which a rib member is joined to a main plate by fillet welding, such as a welded joint of a steel floor slab and a vertical stiffener, It has a flat surface in contact with the main plate and the rib plate, and a recess surrounding the fillet weld, and the surface on the opposite side of the recess has a shape that gradually decreases in thickness toward the flat plate in contact with the main plate and the rib plate. This is a block made of resin.

  The reinforcing resin block of the present invention is fixed by filling the adhesive between the block and the main plate, the rib plate and the fillet welded portion and curing the adhesive in a state where the block is pressed against the main plate and the rib plate. use. By using a reinforced resin block, in addition to the effect of alleviating the stress concentration on the weld toe of the fillet weld, the resin block shares and bears the stress applied to the fillet weld. The fatigue strength of the weld can be improved to prevent fatigue cracks and extend the life of the structure.

The adhesive is made of a material having high adhesion and high rigidity to the main plate and the rib plate such as a plastic putty. The reinforced resin block is preferably formed using an adhesive that adheres the reinforced resin block to the main plate or the like.
In particular, when the reinforcing resin block is formed of the same resin as the adhesive, after the adhesive is cured and fixed by applying the reinforcing resin block, the block portion and the adhesive cured portion are uniformly integrated in the reinforcing portion. Therefore, the fatigue strength at the welded portion is improved, and the effect of extending the life of the structure is great.

If the Young's modulus of the reinforced resin block is significantly lower than that of the main plate and rib plate, the block cannot sufficiently bear the stress applied to the fillet welds. For example, an epoxy putty with relatively high rigidity can be used. It is preferable to use a putty material in which reinforcing fibers are kneaded. In addition, glass fiber, carbon fiber, aramid fiber, iron fiber, etc. can be utilized as the reinforcing fiber.
Moreover, when a plastic metal putty such as an iron putty, for example, in which metal powder is mixed with a polymer putty material, the texture of the surface of the putty layer is close to the texture of the main plate or rib plate, and the finish is good. For example, a putty material (trade name Debcon A (ITW Industry Co., Ltd.) or the like) in which iron powder is kneaded with an epoxy type putty is suitable.

  The surface of the reinforcing resin block can be any shape such as a flat surface or curved surface, but the surface suspended between the main plate and the rib plate should be gradually reduced toward the surface contacting the main plate or the rib plate. Thus, stress concentration at the end of the reinforced resin block can be effectively reduced. In particular, if the surface suspended between the main plate and the rib plate is a concave cylindrical surface toward the fillet weld, it can be easily formed using a cylindrical jig, and the block can be easily fixed to the main plate or rib plate. At the same time, it is preferable because there is an advantage that water can be prevented from being accumulated in the welded portion and the finish is beautiful. Further, for example, a similar effect can be obtained even when a hyperboloid is used.

  The thickness of the reinforcing resin block corresponding to the fillet weld is arbitrary. However, in order to reduce the stress applied to the fillet weld, it is necessary to bear the stress with the reinforced resin block, and thus a thickness of a certain level or more is required. For example, when the surface is a cylindrical surface, the curvature radius of the surface must be at least one times the plate thickness of the main plate. Moreover, it is preferable that the curvature radius of the surface is about 20 times or less the plate thickness of the main plate because the fatigue reduction effect is saturated with respect to the thickness of the reinforcing resin block and the structure is unnecessarily enlarged.

When the reinforcing resin block of the present invention embeds a reinforcing member having higher rigidity than the putty material inside the block, a higher fatigue reduction effect can be obtained.
In particular, when the Young's modulus of the main plate or rib plate is high, when the reinforced resin block is formed only with the putty material, the rigidity of the block is insufficient, and the reinforced resin block cannot sufficiently share the stress applied to the fillet welds. Therefore, the predetermined fatigue reduction effect may not be obtained. In such a case, it is preferable to embed a highly rigid reinforcing member inside the reinforcing resin block so that the reinforcing member bears stress in a supplemental manner.

For example, the reinforcing member can be a plate material such as a steel plate and can be installed in parallel to the surface of the fillet weld. Further, the reinforcing member may be a wire, and may be disposed in a direction against a compressive stress or a tensile stress applied between the main plate and the rib plate. When the reinforcing member is a wire, it is effective to arrange the wire in a direction that spans the opposing surfaces of the main plate and the rib plate. A large number of wires may be arranged side by side as necessary. However, if it is difficult to construct, embed multiple wires in close contact with the crossing line of the main plate and rib plate so that the wire and wire are in contact with each other, and generate resistance against the pressure in the diameter direction of the wire. It may be possible to resist compressive stress.
What is necessary is just to select suitably the material and arrangement | positioning attitude | position of a reinforcement member according to the direction of the stress concerning a main board and a rib board, intensity | strength, etc. FIG.

The reinforced resin block of the present invention can be reinforced by being attached to a vertical stiffener portion particularly in a steel deck such as an expressway.
When applying the reinforcing resin block of the present invention, the state of the target vertical stiffener is examined, and a reinforcing resin block having a suitable shape is selected. If there is no suitable material, a resin block can be molded using a mold material, and if necessary, it can be cut and shaped to form a reinforced resin block that fits.

The shape of the selected reinforcing resin block is further adjusted so as not to interfere with other things according to the actual situation at the site. Next, the adhesion surface of the steel floor slab to which the resin block is bonded and the vertical stiffener are shaved with a grinder to remove the coating film, and an adhesive such as a plastic metal putty is placed on the adhesion surface to press and fix the reinforcing resin block. .
The gap created between the adhesive surface and the resin block is filled with adhesive, and this part of the adhesive solidifies and integrates with the reinforced resin block to share the stress and weld toe of the fillet weld Demonstrates the effect of relieving stress concentration on

By utilizing the present invention, the construction time on site can be shortened, the construction can be simplified, and high reinforcement performance can be exhibited without using a skilled worker.
The steel plate slab vertical stiffener to which the reinforced resin block of the present invention is applied reduces stress concentration on the fillet weld, reduces stress fatigue at the weld toe, and improves the fatigue strength of the joint structure As a result, an effect of extending the structure life several times can be obtained.

Hereinafter, the best mode of the reinforcing resin block of the present invention will be described in detail with reference to the drawings.
FIGS. 1 to 15 are drawings for explaining a fatigue-reducing welded joint structure and a reinforced resin block according to one embodiment of the present invention, and FIGS. 16 to 18 are drawings showing an example of a conventional welded joint structure.

  FIG. 1 is a perspective view illustrating the shape of a reinforced resin block of the present embodiment, FIG. 2 is a perspective view showing a fatigue-reducing welded joint structure in which the reinforced resin block is applied to a steel stiffener vertical stiffener, and FIG. FIG. 4 is a cross-sectional view when the fatigue-reducing welded joint structure of the embodiment is cut vertically, FIG. 4 is a cross-sectional view when cut horizontally along the line IV-IV in FIG. 3, and FIG. It is the top view observed from the upper surface except.

  The reinforcing resin block of the present embodiment is a column having a cross section having a substantially right triangle in an axis parallel to the fillet weld line, and is formed on the fillet weld portion formed so as to go around the butt portion of the member. In this case, the stress concentration generated in the vicinity of the welded portion is alleviated by using the flattened portion of the member sandwiching the welded portion with an adhesive.

  On highways and other high-traffic roads, the steel plate slab of the elevated part has a structure that supports the deck plate with the main girder, but the main girder stretches the floor surface and the ceiling surface of the deck plate at an appropriate interval. A supporting vertical stiffener is provided. The deck plate and the vertical stiffener are joined by fillet welding, but fatigue cracks may occur in the vicinity of the weld due to the vehicle load traveling on the road. Fatigue cracks are largely caused by stress concentration that rapidly increases in the vicinity of the weld.

On the other hand, by applying the reinforcing resin block of this embodiment, it is possible to relax the stress concentration in the vicinity of the welded portion, increase the fatigue strength, and have the effect of extending the life of the structure.
A reinforcing resin block set 1 shown in FIG. 1 is applied to a portion where a main plate deck plate 2 and a rib plate vertical stiffener 3 are fillet welded as shown in FIG. It is fixed to the main girder web 4 with fillet welds 32 and surrounds the vertical stiffener 3 from three sides to reinforce it, so that it is sandwiched between a pair of plane-symmetric reinforcing resin blocks 11 and 12. The wedge-shaped reinforcing resin block 13 is arranged in three blocks.

A pair of plane-symmetric blocks 11 and 12 include vertical surfaces a and a ′ that contact the vertical stiffener 3, horizontal surfaces b and b ′ that contact the lower surface of the deck plate 2, and edge lines between the horizontal surface and the vertical surface. Concave surfaces d and d ′ stretched between them, front end surfaces e and e ′ facing the free end side of the vertical stiffener 3, and back end surfaces f and f ′ contacting the main girder web 4.
Usually, since the deck plate 2, the vertical stiffener 3 and the main girder web 4 are perpendicular to each other, the vertical surfaces a and a ', the horizontal surfaces b and b' and the back end surfaces f and f 'are perpendicular to each other.

  The concave curved surfaces d and d ′ are shaped so that the thickness of the block becomes thinner as it approaches the deck plate 2 and the vertical stiffener 3 when the block is attached to the joint between the deck plate 2 and the vertical stiffener 3. Have For example, a column having a curved surface such as a cylinder, an elliptical column, or a hyperboloidal column can be easily formed using a mold.

  In use, the ridges c and c ′ are formed so that the ridgeline where the vertical surfaces a and a ′ and the horizontal surfaces b and b ′ meet is scraped off so as not to interfere with the fillet welds 31 of the deck plate 2 and the vertical stiffener 3. Before use. Indented surfaces c and c ′ indicated by a one-dot chain line in FIG. 1 can be processed on-site in accordance with the actual fillet weld 31. Further, the recessed surfaces c and c 'may be formed in advance at the time of block molding so as to be a recess having a size that surrounds the fillet weld.

  The tip surfaces e and e 'are vertical inclined surfaces, and as can be seen from the horizontal cross-sectional view of FIG. 4, the wedge-shaped block 13 is disposed so as to be sandwiched between these inclined surfaces.

  The wedge-shaped block 13 includes a narrow vertical surface g that contacts the end surface of the vertical stiffener 3, a horizontal surface h that contacts the lower surface of the deck plate 2, and a recess stretched between the horizontal plane h and the edge of the vertical surface g. The curved surface j has wedge surfaces k and k ′ that come into contact with the tip surfaces e and e ′ of the plane-symmetric blocks 11 and 12. The recessed surface i for preventing interference with the fillet welded portion 31 at the tip of the vertical stiffener 3 is formed at the time of molding in addition to being processed in the same manner as the recessed surfaces c and c ′ of the blocks 11 and 12. can do.

As shown in FIG. 3, the pair of plane-symmetric blocks 11 and 12 are arranged so that the vertical stiffener 3 is sandwiched between the vertical planes and bonded by the adhesive 5, and the horizontal planes of the deck plate 2 are respectively It is used by being bonded to the bottom surface with the adhesive 5.
Since the concave surface is provided, interference between the deck plate 2 and the fillet welded portion 31 that joins the vertical stiffener 3 can be avoided, and the deck plate and the vertical stiffener can be brought into close contact with each other.

  4 and 5, the wedge block 13 is sandwiched between a pair of plane-symmetric blocks 11 and 12 and integrated by an adhesive, and is formed at the upper end of the vertical stiffener 3. The fillet welded portion 31 with the deck plate 2 formed so as to surround the three sides can be surrounded, and the vicinity of the edge portion of the vertical stiffener 3 where fatigue cracks are likely to occur can be protected.

The gap formed between the three blocks and the structural material is filled with an adhesive, and after the adhesive is cured, the reinforcing resin blocks 11 and 12 are integrated with the adhesive 5 to form the deck plate 2 and the vertical stiffener. 3 to form a fatigue-reducing welded joint structure, share the stress generated in the deck plate 2 and the vertical stiffener 3 to alleviate stress concentration and extend the life of the structure.
Similarly, for the fillet welded portion 41 between the deck plate 2 and the main girder web 4, a groove portion for avoiding interference is formed in the ridgeline portion where the reinforcing resin blocks 11 and 12 abut, and the adhesive 5 is filled. And unite.

Various combinations of the reinforced resin block set are possible.
FIG. 6 is a perspective view illustrating a reinforcing resin block having another shape according to the present embodiment, and FIG. 7 is a plan view of the application state observed from the upper surface except for the deck plate.
The reinforcing resin block set 1 ′ of this embodiment includes a pair of triangular pyramid blocks 11 ′ and 12 ′ that are symmetric with respect to each other and a square pyramid with one pseudo quadrangular pyramid shape. It consists of block 13 '.

The triangular base blocks 11 ′ and 12 ′ include a vertical surface that abuts on the vertical stiffener 3, a horizontal surface that abuts on the lower surface of the deck plate 2, a concave curved surface stretched between the horizontal plane and the edge line of the vertical surface, and a main girder web. 4 and a distal end surface parallel to the rear end surface on the free end side of the vertical stiffener 3. The four surfaces other than the concave curved surface are orthogonal to each other.
Due to the concave curved surface, the thickness of the block decreases as it approaches the deck plate 2 and the vertical stiffener 3.

  The quadrangular pyramid block 13 ′ is located between the end surface of the vertical stiffener 3 and the front surface of the triangular base block, the horizontal surface that contacts the lower surface of the deck plate 2, and the three horizontal edges and the edge of the vertical surface. It has three concave curved surfaces.

When the reinforcing resin block set of this aspect is assembled, it is sufficient to align the plane of the quadrangular pyramid block 13 ′ with the tip surface of the triangular block 11 ′, 12 ′ and fix it with an adhesive, and thus the configuration is easy.
At the time of forming the structure, the ridge line portion where the vertical plane and the horizontal plane are combined is scraped off to form a concave surface indicated by a one-dot chain line in FIG. 6 so as not to interfere with the fillet weld portion 31. The concave surface may be processed on-site in accordance with the actual fillet welded portion 31, or may be formed in advance at the time of block molding.

The reinforcing resin block can be manufactured using a mold material.
Make a mold box with a surface corresponding to the flat part and a fluororesin sheet affixed to the inner surface, and a cylindrical pressing mold with the desired radius of curvature and covered with a fluororesin sheet. The kneaded putty material is filled, the pressing die is pressed and fixed, and after 24 hours, it hardens to a considerably high degree.

The fatigue strength of the block can be increased by embedding a glass fiber reinforced plastic sheet (GFRP sheet), a steel plate, a steel wire, or the like inside the reinforced resin block.
For example, as a reinforcing member, a plate material such as a steel plate may be installed parallel to the surface of the fillet welded portion, or the wire material may be arranged in a direction against compressive stress or tensile stress applied between the main plate and the rib plate. When the reinforcing member is a wire, it is effective to arrange the wire in a direction that spans the opposing surfaces of the main plate and the rib plate. A large number of wires may be arranged side by side as necessary.
What is necessary is just to select suitably the material and arrangement | positioning attitude | position of a reinforcement member according to the direction of the stress concerning a main board and a rib board, intensity | strength, etc. FIG.

  As the putty material, for example, an iron putty (trade name: Devcon A) in which iron powder is kneaded with an epoxy-based putty can be used. This putty can also be used as an adhesive for joining the reinforcing resin blocks 11, 12, 13 to the deck plate 2 and the vertical stiffener 3. When the block and adhesive are made of the same material, the stress-removed beam body does not have a boundary surface that changes its characteristics when the fatigue-reducing welded joint structure is formed, so that the stress can be dispersed smoothly. it can.

FIG. 8 is a flowchart for explaining the construction procedure of the reinforcing resin block.
If the construction conditions are examined for the application target and it is decided to perform the construction (S1), then the shape of the block that matches the target structure is selected (S2). At this time, structural analysis is performed to determine the curvature of the concave surface, the size of the plane, and the like.
A suitable block is produced (S3). The basic shape of the block is formed by molding a putty material, and the detailed shape adjustment is performed by cutting.

Next, as field work, shape adjustment is performed so as not to cause interference or the like according to each position where the reinforcing resin block is applied (S4).
Next, preparation for application of the adhesive surface to which the reinforcing resin block is applied is performed. The adhesive surface of the vertical stiffener and the deck plate is polished using a grinder having a particle size of 40 to 400 to remove the coating film on the adhesive surface, and degreased using a solvent such as acetone (S5).

  An adhesive is applied to the bonding surface, and the reinforcing resin block is bonded (S6). At this time, when a space is formed by leaving the surface of the reinforcing resin block, the adhesive is sufficiently accumulated so that the adhesive fills the space when the block is pressed so that no gap is generated.

After pressurizing the bonding surface with the mold, a support mechanism is configured to support the block and the mold so as not to move (S7). In particular, as a mold for suppressing and supporting the concave curved surface, it is possible to use a pipe having a radius that is the same as the curvature of the concave curved surface and cut. Since the deck plate and the like are made of steel, a magnet base that can be attached and detached by magnetic force can be used as a simple support mechanism.
When using a hard adhesive, this step (S7) can be omitted.

After curing until the adhesive is sufficiently cured (S8) and removing the support material such as the formwork (S9), the steel deck can be put into service (S10).
Note that the iron putty may be left for about 30 minutes until it can be used. Even if the adhesive layer is extremely thick, the planned strength can be obtained after 24 hours of curing.
By using the reinforced resin block of the present invention, instead of depositing putty material directly on the structure at the site, it is easier to simply bond the block to the steel plate with an adhesive, and in a shorter curing time, The same effect as the fatigue-reducing welded joint structure disclosed by the inventors can be obtained.

In the fatigue-reduced welded joint structure disclosed above, the life of the joint structure is 1.6 times before reinforcing when the radius of curvature of the concave curved surface is 20 mm, and 2.4 times when it is 25 mm. In addition, by embedding the steel plate in a resin shape with a curvature radius of the concave curved surface of 25 mm, the life is 1.2 times that of the case of using only the putty material.
Moreover, as a result of calculating by simulation about the effect which relieve | moderates the stress concentration concerning the toe part of fillet weld, when the curvature radius of the concave curved surface is 18 mm (3 times the plate thickness t of the main plate), the tensile load is about 0. There was a stress concentration relaxation effect of about 0.75 times with respect to the plate bending load of .9 times. When the curvature radius of the concave curved surface is increased to 4t and 5t, the stress concentration mitigating effect on the plate bending load increases dramatically. When the curvature radius is 5t, the stress concentration at the toe is half that before construction. It becomes the following.

  In addition, increasing the Young's modulus of the putty material increases the stress concentration mitigating effect for both tensile load and plate bending load. Therefore, when the Young's modulus of the putty layer is increased by using, for example, a reinforcing fiber kneading putty kneaded with glass fiber, carbon fiber, aramid fiber, iron fiber, or by embedding a reinforcing member such as a steel plate or steel wire. It is effective.

The reinforcing resin block of the present embodiment is the same as the matter disclosed previously in the shape and the embedded object, so that the welded joint structure in which the block is bonded and bonded has the same life-prolonging effect as the fatigue-reduced welded joint structure disclosed above. Bring.
Therefore, the work rationalization effect by this invention is large.

The effect by joining the reinforcement resin block in a present Example to a fillet weld part was confirmed using FEM analysis.
FIG. 9 is a perspective view showing a model of a conventional joint structure used for FEM analysis, FIG. 10 is a perspective view showing a model of this embodiment, and FIGS. 11 to 14 are main plate sides and ribs when a predetermined force is applied. FIG. 15 is a graph for explaining the effect of the reinforcing resin block on the deck plate and the vertical stiffener.

As shown in FIG. 9, the analysis model is represented by a conventional structure for comparison in which a deck plate and a vertical stiffener are joined by fillet welding. The Young's modulus of the steel plate is 200 GPa, and the Young's modulus of the reinforcing resin block is 6 GPa.
Moreover, the fatigue reduction type welded joint structure in the present invention is obtained by surrounding a weld bead with a reinforcing resin block as shown in FIG. 10 with respect to the structure of FIG. The radius of curvature ρ of the concave curved surface was 50 mm.
In any case, the end face B is completely constrained, and a shearing force and a moment force directed vertically downward are applied at the center point P of the ridge on the other end side.

At this time, the reinforcing resin block joins the relationship between the horizontal stress in the deck plate and the horizontal distance x from the weld toe Ox, and the relationship between the vertical stress in the vertical stiffener and the vertical distance z from the weld toe Oz. A comparison was made between the case of being bonded and the case of not being bonded.
FIG. 11 is a relationship diagram when a shear force is applied to the deck plate, and FIG. 12 is a relationship diagram when a moment force is applied. FIG. 13 is a relational diagram when a shear force is applied to a vertical stiffener, and FIG. 14 is a relationship diagram when a moment force is applied. In the figure, the horizontal axis and the vertical axis are each an appropriate linear scale that does not specify a unit.

The hot spot stress at a distance of 0.3 times the plate thickness t from the toe of the welded portion represented by a dotted line in the figure corresponds to the fatigue strength of the member in the vicinity of the welded portion.
From FIG. 11 and FIG. 12, when the reinforcing resin block is joined in the welded joint structure, the hot spot stress of the deck plate is reduced to about 26% when the shear force is applied, and about 38 when the moment force is applied. It can be seen that it has decreased to%.
Further, from FIGS. 13 and 14, when the reinforcing resin block is joined in the welded joint structure, the hot spot stress of the vertical stiffener decreases to about 37% when the shear force is applied, and the moment force is applied. In some cases reduced to about 36%.
Since the life is inversely proportional to the cube of the hot spot stress, if these values are used, a life extension effect of about 18 times can be expected.

In addition, various structures are used in the actual steel deck, and the acting load is a combination of shear force and moment force.
FIG. 15 is a graph showing a result of confirming a reinforcing effect by performing a loading test by constructing a reinforcing resin block on the vertical stiffener of the steel deck specimen and the fillet weld of the deck plate.
For vertical stiffeners with reinforced resin blocks and vertical stiffeners that have not been installed, the wheels of the truck loaded 10 tons at the same distance on the loading stage in the vertical direction with respect to the main girder of the deck plate The hot spot stress was estimated and compared from the stress measured with a strain gauge installed near the welded part of the vertical stiffener and the deck plate.

  In FIG. 15, the left figure is a drawing showing hot spot stress occurring in the deck plate, and the right figure is a drawing showing hot spot stress occurring in the vertical stiffener. The figure shows data on three loading positions at different distances from the welded portion, and the solid line represents the hot spot stress in the vertical stiffener with the reinforced resin block applied, and the dotted line represents the vertical stiffener not applied.

As shown in FIG. 15, the vertical stiffener with the reinforced resin block shows a stress relaxation effect of about 30 to 50% compared to the unreinforced vertical stiffener. It showed a relaxation of nearly 50% when loaded close.
This result is represented by the Japan Steel Structure Association (JSSC) recommended relationship between stress and life. Σ ³ N = 1.024 × 10 ¹²
(However, σ: Stress range (MPa), N: Life (times))
If applied to the above, a life extension effect of 2.8 to 7.6 times can be expected.

As described above, according to the fatigue reduction type welded joint structure of this example, the putty layer laminated on the fillet weld part reduces the stress applied to the fillet weld part, and the stress concentration applied to the weld toe part is reduced. Since it relaxes, the fatigue crack of the fillet welded part due to repeated stress can be prevented, and the fatigue life of the welded joint can be improved.
Moreover, the use of pre-molded reinforced resin blocks significantly simplifies on-site work and shortens the work period by shortening the construction period because it takes only a short period of time for puttingty materials and adhesives to be cured. The time until resuming service can be shortened even when reinforcement work is performed.

It is a perspective view which illustrates the shape of the reinforcement resin block concerning one Example of this invention. It is a perspective view which shows the fatigue reduction type welded joint structure which applied the reinforced resin block concerning a present Example to the steel deck slab vertical stiffener. It is the cross section which cut | disconnected perpendicularly the fatigue reduction type welded joint structure of a present Example. It is sectional drawing when cut | disconnected horizontally by the IV-IV line of FIG. It is the top view which observed the application state of the reinforcement resin block of a present Example from the upper surface except the deck plate. It is a perspective view which illustrates the reinforcement resin block which has another shape of a present Example. It is the top view which observed the application state of the reinforced resin block of FIG. 6 from the upper surface except the deck plate. It is a flowchart explaining the construction procedure of the reinforced resin block of a present Example. It is a perspective view showing the model of the conventional joint structure used for FEM analysis. It is a perspective view showing the model of the joint structure of the present Example used for FEM analysis. It is a related figure of the stress which generate | occur | produces in a deck plate when the shear force is applied calculated | required by FEM analysis. It is a related figure of the stress which generate | occur | produces in a deck plate when the moment force was calculated | required by FEM analysis. It is a related figure of the stress which generate | occur | produces in a vertical stiffener when a shear force is applied calculated | required by FEM analysis. It is a related figure of the stress which generate | occur | produces in a vertical stiffener when applying a moment force calculated | required by FEM analysis. It is a graph which shows the result of having confirmed the reinforcement effect of a reinforced resin block by the steel floor slab loading test. It is sectional drawing explaining the welding part fatigue strength improvement method in patent document 1. FIG. It is a perspective view which shows the fatigue reduction type welded joint structure disclosed previously. It is a perspective view explaining the manufacturing method of the fatigue reduction type welded joint structure disclosed previously.

Explanation of symbols

1, 1 'Reinforcement resin block set 2 Deck plate 3 Vertical stiffener 4 Main girder web 5 Adhesive 11, 12 Reinforcement resin block 13 Wedge-shaped reinforcement resin block 11', 12 'Triangular block 13' Square pyramid block 31, 32, 41 Fillet welded portion 100 Main plate 101 Rib plate 102 Fiber reinforced plastic (FRP)
103 Weld toe 104 Fillet weld 105 Main plate 106 Rib plate 107 Welded part 108 Putty layer 109 Cylindrical mold 110 Fluororesin sheet 111 Wood part

Claims (12)

  The welded joint part that fixes the main plate and the rib plate has two planes that are perpendicular to each other and that are in contact with the surface sandwiching the welded joint part of the main plate and the rib plate. Prepare a reinforcing resin block having a beam body whose thickness gradually decreases toward the surface, apply an adhesive by roughening the area where the reinforcing resin block of the rib plate and the main plate abut, and apply the adhesive A method for forming a fatigue-reducing welded joint structure, wherein a reinforcing structure of a welded joint of a main plate and a rib plate is formed by pressing and fixing the reinforcing resin block to each of the finished surfaces and curing the adhesive.   The fatigue reduction type welded joint structure forming method according to claim 1, wherein the main plate is a steel deck and the rib plate is a vertical stiffener.   A reinforced resin block applied to a welded joint structure in which a rib material is joined to a main plate by fillet welding, two perpendicular planes facing the surfaces of the main plate and the rib plate, and the main plate and the rib plate It has a surface having a shape whose thickness gradually decreases toward the two planes, and a beam body is formed between the two planes, and the main plate and the rib are bonded to each of the two planes with an adhesive. Reinforced resin block that is fixed and reinforced on a plate.   The reinforcing resin block according to claim 3, wherein a dent that surrounds the fillet weld portion is formed in a ridge line portion formed by two planes perpendicular to each other facing the surfaces of the main plate and the rib plate.   The reinforcing resin block according to claim 3 or 4, wherein the beam body is formed of a plastic putty.   The reinforced resin block according to claim 5, wherein the plastic putty is an epoxy putty.   The reinforcing resin block according to claim 5 or 6, wherein the beam body is formed of a plastic steel putty in which metal powder is mixed with a plastic putty material.   The reinforcing resin block according to claim 3, wherein reinforcing fibers are kneaded in a putty material forming the beam body.   The reinforcing resin block according to claim 8, wherein the reinforcing fiber is one of glass fiber, carbon fiber, aramid fiber, and iron fiber.   10. The reinforcing resin block according to claim 3, wherein a cross-sectional shape of the beam body is an arc shape having a concave surface in a cross section cut perpendicularly to an intersection line of the main plate and the rib plate.   11. The reinforcing resin block according to claim 10, wherein a radius of curvature of a cross-sectional shape of the beam body is 1 to 20 times a plate thickness of the main plate. The reinforcing resin block according to any one of claims 3 to 11, wherein a reinforcing member having higher rigidity than a putty material forming the beam body is embedded in the beam body.

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