JPH08155679A - Backing steel plate for welding rectangular column - Google Patents

Abstract

PURPOSE: To suppress the clearance as small as possible to the degree where there is no problem in the welding, and to facilitate the working in the steel plate for the backing to be used for the welding of a square column of a steel structure even when the curvature on the inner side of the square column is dispersed. CONSTITUTION: A group of >=8 and <=10 V-shaped grooves 6 are provided on the parts corresponding to a square column and the respective curved parts on the inner side of the corner parts, and the depth of the V-shaped grooves 6 is the thickness of a backing steel plate minus 1.7 to 4mm, and the angle of the V-shaped grooves 6 is >=90/n (degrees) to <=110/n (degrees) where (n) is the number of the V-shaped grooves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding backing plate for welding the corners of a square column in a steel frame structure using the square column. A cold-formed rectangular steel pipe can be used.

[0002]

2. Description of the Related Art Square columns, which are often used in columns of steel construction, are welded to steel plates (called diaphragms) by welding the square columns 2 as shown in FIG.
A so-called through-diaphragm joining method of welding and joining the beam 4 to the diaphragm steel plate 3 is often used. When this joining method is adopted, butt welding is generally used for welding the square column that is the column and the diaphragm steel plate as shown in the cross section of the welded portion in FIG. 3, and the backing plate 1 is used for welding. The four corners of the rectangular column have a cross-sectional shape with a certain curvature, so that a backing metal having a shape along the curvature is also used.

The gap between the inner surface of the corner of the corner column and the backing plate should be as close as possible for good welding, but the curvature of the corner of the corner column depends on the thickness of the corner column. Depending on the difference between the corners, there are variations in manufacturing in the four corners, and the target value of the corner curvature differs depending on the manufacturer of the corner column. It is usual to make a backing metal together. However, due to the above reasons, there is variation in the curvature of the inner surface of the corner of the square column, and it is difficult to finely adjust the bending curvature with the jig used to bend the steel plate into the backing metal. It is extremely difficult to make a backing metal that adheres to the inner surface of the corner of the column.
Normally, a clearance of up to about 2 mm is allowed, but it requires skill to manufacture the backing plate, and if the clearance is large, it causes welding defects during welding. The manufacturing quality and cost efficiency of steel frame structures using square columns Has become a major problem that undermines.

For this reason, some proposals have been made on how to attach the backing plate to the square column. For example, in Japanese Unexamined Patent Publication (Kokai) No. 4-284997, a long slit plate to be used as a backing plate is formed into a cylindrical roll corresponding to the inner circumference of the column and cut, and this is brought to a mounting position in the column. A method is shown in which, while rolling the column, it is pressed against the inner wall of the column from the end by a roller or the like and fixed by spot welding. However, this method requires large-scale equipment such as a column transfer skid and a turning device, and is not applicable to on-site work because it can be applied only in limited cases.

On the other hand, as a method which can be applied without the need for such a large-scale facility, a flat steel to be a backing metal as shown in Japanese Utility Model Laid-Open No. 63-157497 is provided with a notch groove in advance, There is one that bends to match the inner wall of the corner column when used.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the method of pre-grooving the flat steel of No. 57497, four square grooves each having a certain width are provided at positions corresponding to the respective corner portions of the square column. The present inventors conducted an experiment on the backing metal shown in the embodiment of the present invention, but did not obtain a good result. That is, FIG. 4 is a perspective view showing a bent portion of the backing plate of the above invention, but a portion 2 provided with a groove is shown.
It was found that a dent 21 is formed on the back surface of 0 to form a bent line shape, and a gap is formed between the dent 21 and the inner wall of the corner column, which causes welding failure, that is, a defect in the root portion.
This Japanese Utility Model Application Laid-Open No. 63-157497 describes that the groove of the backing metal can be appropriately changed in shape, size, depth, and the number of pitches. There is no indication what to do.

In contrast to the above-mentioned problems, the present invention makes it possible to minimize the gap to the extent that there is no problem in welding even if there is variation in the curvature on the inner surface side of the rectangular column, and it is easy to machine. It is intended to provide a steel plate for a backing plate.

[0008]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems and provides a backing for butt welding of square columns, which is provided in a straight state and is bent according to the inner dimensions of the square columns. In the steel plate for use, a group of V-grooves having a number of 8 or more and 10 or less is provided in a portion to be applied to the curved surface inside the corner of each corner column, and the depth of the V-groove is the same as that of the backing steel plate. The value is obtained by subtracting 1.7 to 4 mm from the plate thickness, and the angle of the V groove is 90 / when the number of V grooves in the group is n.
It is a steel plate for welding backing of a square column, characterized in that it is not less than n degrees and not more than 110 / n degrees.

Further, at least one V-groove on each side of the group of at least one V-groove in the above-mentioned welded backing steel sheet, not more than two V-grooves on each side, is to be applied to the curved surface inside the corner of the square column. It is also characterized in that it is added over a range longer than the length. Further, the length of the portion to be applied to the curved surface portion inside the corner portion of the above-mentioned corner column is such that the radius of curvature inside the corner portion of the corner column is r, and the remaining thickness of the backing steel plate at the V groove portion is t _b . Then, π (r-t _b) it is / 2, at two positions or four positions of the total length of the backing steel plate provided with a group of V-grooves, from each of the longitudinal ends of said backing steel plate Another feature is that a difference is provided in the length to the first V groove.

[0010]

The present invention is one in which a notched groove is provided in a steel plate for welding backing, and the optimum shape has been found by repeating theoretical elucidation and experiments. As shown in the perspective view of FIG. 1, the welded backing steel plate of the present invention is provided with a plurality of V-grooves 6 in the portion to be bent of the backing steel plate 5, respectively. At this time, the distance m between the central portions of the respective V-groove groups of the backing steel sheet shown in FIG. 5 (a) and the central portion of the curved surface portion of the inner surface of the adjacent corner portion of the corner column shown in FIG. 5 (b). Match the distance. Note that the distance m in FIG. 5 (b) is not exactly the inner surface of the corner column itself, but as shown in FIG.
It is the distance on the curved surface 10 connecting the bottoms of the grooves of the backing metal 1 in (b) and its extension. 1 and 5
(A) has a group of V-grooves at two locations, but it is also possible to weld the entire inner circumference of the rectangular column with a single backing metal by using V-grooves provided at four locations.

By making the shape of the groove V-shaped as described above, when the backing steel plate is bent, the surfaces of the groove can be brought into close contact with each other, which is preferable because no space remains. As a result, since the bending force is reduced, the remaining thickness of the backing steel sheet at the groove portion is small, and even if the grooved portion is melted during welding, there is no possibility that the molten metal will melt down into the space. It should be noted that the shape of the V groove may be practically no problem even if the bottom portion is not a complete acute angle and is slightly rounded, and this can be done in order to improve the processing efficiency.

In the present invention, the number of V grooves is 8 or more and 10 or less in each group. That is, when the backing steel plate is bent, 8 or more and 10 or less V grooves are provided in the range of the length of the portion that should hit the curved surface inside the corner column. Further, one or two V-grooves may be added on both sides of the above range of length in order to cope with errors in the length and curvature of each side of the corner column. The depth of the V groove is a value obtained by subtracting 1.7 to 4 mm from the thickness of the backing steel plate. These conditions are determined by theoretical devising and verification by experiments, and the reasons are described below.

In order to bend the V-grooves manually, it is necessary that the residual thickness of the V-groove portion of the backing steel plate be 3 mm or less. Considering bending with a simple jig such as a vise, it should be 4 mm or less. The force required for this bending can be calculated as follows. That is, as shown in FIG. 6, the residual thickness of the groove portion is t _b ,
If the width of the steel plate is w and the tensile strength is σ _B , the stress distribution is 7
, The resultant force T is t _b × w × σ _B , and the bending moment M is expressed by the following equation, with the bending fulcrum being the bottom of the V groove and the force point being half the residual plate thickness. _{M = T × t b / 2} = w · t b 2 · σ B / 2

For example, σ _B = 50 kg / mm ² , w = 2
If 5 mm and t _b = 2 mm, it will be 250 kg · cm, and it can be bent with a force of 25 kg at a position separated by 10 cm from the bending position, and can be easily bent manually. When this becomes t _b = 4 mm, it becomes 1000 kg · cm, which is a limit even if a tool such as a vise is used. Therefore, in the present invention, the lower limit of the depth of the V-groove is 4 from the thickness of the backing steel plate.
The value was obtained by subtracting mm. On the other hand, the upper limit was set to a value obtained by subtracting 1.7 mm from the thickness of the backing steel plate because the strength is not preferable in terms of handling if the residual thickness is too small.

The inventor of the present invention has considered the cause of forming the recess 21 as shown in FIG. 4 on the outer surface of the bent portion when the backing steel plate is bent during use. As a result, it was found that the elongation of the outer surface of the bent portion should be within the range of uniform elongation of the material. That is, in the tensile test of the material, the material uniformly stretches until the maximum stress of the stress-strain curve is reached, but when the maximum stress is reached, a part of the material begins to become constricted and eventually breaks at a position where the cross section becomes narrow. That is, it was found that the occurrence of the depression 21 corresponds to the occurrence of necking of the material in the tensile test, and such a depression does not occur if the material is stopped within the range of uniform elongation.

The condition of the V groove satisfying this condition is obtained as follows. That is, when the portion having the V groove shown in FIG. 7A is bent as shown in FIG. 7B, the plastically deformed portion 8 is generated. The following equation (1) is established under the condition that the total stress at the maximum stress line and the total stress at the yield start line are equal. σ _y × L ₁ × w = σ _B × t _b × w (1)

Where σ _y is the yield stress, σ _B is the tensile strength, and w is the strip width. On the other hand, the equation (2) is established in the right triangle of FIG. L ₁ ² = t _b ² + (L _P / 2) ² (2)

When L ₁ is eliminated from the equations (1) and (2) and a value of σ _b / σ _y = 1 / 0.8 = 1.25 for ordinary mild steel is entered, the relation of the equation (3) is obtained. Is required. L _p = 1.5t _b (3)

On the other hand, assuming that the surface strain e is the original length s, the elongation is almost (t) from the geometrical symmetry in FIG. 7A.
_{Since b} / t _a ) · g _0, it becomes as shown in equation (4). e = (t _b / t _a ) · g ₀ / s (4)

On the other hand, the relationship of the equation (5) is established by the definition of the distortion amount. L _p = (1 + e) s (5)

Therefore, s can be eliminated from the equations (4) and (5), and the equation (6) can be derived from the relation of the equation (3). _{e = (t b / t a} ) · g 0 / {L p - (t b / t a) · g 0} = (1 / t a) · g 0 /{1.5-(1/t a)・ G ₀ } (6)

On the other hand, the range of uniform elongation is e in mild steel.
Since it is about ≦ 20%, this leads to (7) from equation (6).
A formula can be derived. g ₀ ≦ 0.25t _a (7)

That is, in order to prevent the occurrence of deep dents on the outside of the bent portion as shown in FIG. 4, the width of the V groove is 1/4 or less of the depth, and the angle of the V groove is 14. This means that it must be less than twice.

By the way, the depth t _a of the groove is determined under the condition that the residual thickness of the backing steel plate should be 1.7 to 4 mm in order to secure bendability and strength as described above. width g ₀ of it comes to be limited in relation to the depth t _a of the groove as described above. This limits the number of V-grooves provided in each bent portion of the backing steel sheet as follows.

FIG. 8 shows a situation in which the backing steel sheet shown in FIG. 8 (a) is bent at one corner portion of a rectangular column as shown in FIG. 8 (b). Here, the backing steel plate thickness t,
If the radius of curvature of the inner surface of the column is r, the length of the curved surface portion of the inner surface of the square column is πr / 2, and the length of the inner surface portion after bending the backing steel plate is π (rt). / 2. Also, on the plane 9 that connects the bottoms of the V grooves, it becomes a neutral surface,
When the backing steel plate is bent, its length does not change. The length of the communicating et Neru curved base 10 of the V-groove is _{π (r-t + t a} ) /
It becomes 2. Therefore, the width and the number of V grooves are g ₀ and n, respectively.
Then, the equation (8) is established. _{π (r-t + t a} ) / 2-π (r-t) / 2 = g 0 n ··· (8)

By transforming equation (8), equation (9) is obtained. g ₀ = πt _a / (2n) (9)

Substituting equation (9) into equation (7) yields (10)
The formula holds. n ≧ 2π ... (10)

That is, the required number of V-grooves is irrelevant to the curvature of the corner portion of the rectangular column, the thickness of the backing steel plate, the depth of the V-grooves, etc., and it is a very simple conclusion that 7 or more are sufficient. become. Actually, the present inventors have conducted various experiments, but the number of V-grooves is preferably 9 or more, and the limit is 8 in order to perform good bending without dents on the outer surface when bent. In the book, a dent appeared on the outer surface and was somewhat unsatisfactory.

The present invention has been made by repeating the above-described theoretical device and experiment, and from the above results, the number of V-grooves is 8 or more for each bent portion. On the other hand, when the number is large, the time and labor required for grooving the backing steel sheet increases, and the profit is small for that reason, so 10 or less is appropriate. The length of the section in which the group of 8 to 10 V-grooves is provided is obtained as follows.

In FIG. 8A, if the distance between the centers of adjacent V-grooves, that is, the pitch is p, the part of length k obtained by adding p / 2 to the outside of the V-grooves at both ends is a corner when bent. It will bend most smoothly if it hits a curved surface inside the corner of the column, that is, an arc of a quadrant.

By the way, when the backing steel plate is bent, the portion outside the surface 7 connecting the bottoms of the grooves extends due to plastic deformation,
The amount on the outer surface is maximum. And the amount is (1
It can be calculated as in equation (1). πr / 2-π (r- t + t a) / 2 = π (t-t a) / 2 = πt b / 2 ······· (11)

That is, the amount of elongation when bent depends only on the remaining thickness t _b of the backing steel sheet at the bottom of the V groove. For example, if the remaining thickness is 2 mm, it is 3.1 mm. It will grow. Strictly speaking, the remaining thickness t _b itself is reduced by bending, but it is ignored here. Therefore, the length k of the section where the groove should be formed is (11) when the backing plate is bent from the length of the curved surface of the column.
Equation (12) is obtained by subtracting the elongation of the outer surface portion according to the equation. k = (πr−πt _b ) / 2 = π (r−t _b ) / 2 ... (12)

The portion to be applied to the curved surface portion inside the corner portion of the corner column of the backing steel plate according to the present invention is defined as the portion having the length k as shown in FIG. 8 (a). As described above, the V-grooves may be provided at a pitch obtained by dividing this section by the number of V-grooves. However, as shown in FIG. 8 (a), even if the length of p / 2 is not exactly provided on both sides outside the V groove at both ends in the section of k, 8 to 10 V grooves are provided in this section. If it is included, there is no practical problem. Note that FIG.
Regarding the measurement position of the length of m, it is stated that it is not the inner surface itself of the rectangular column but the curved surface 10 connecting the bottoms of the V grooves in FIG. 8B and its extension. This is clear from the fact that this position becomes the neutral plane and the length does not change when bent.

On the other hand, the number of V-grooves is increased in consideration of the error in the curvature of the corners of the corner column and the length between the corners, and the length from one end of the group of V-grooves to the corners. It can also be made longer than the length of the inner curved surface portion. In this case, two or less grooves may be added on one side or both sides on each side. Therefore, for example, a group of Vs on a curved surface
When the number of grooves is 9, and the number of grooves is further increased on both sides, the maximum number of V grooves increases by 2 on each side to 13 grooves. The space between the added V-grooves may be the same as that of the curved surface portion. Normally, all V-groove groups should be added in the same way on both sides,
Depending on the situation of the dimensional error of the rectangular column, it may be added only to some V-groove groups.

The lower limit of the angle of the V-grooves is 90, where n is the number of V-grooves because the corner portion is bent at a right angle in the entire V-groove.
/ N degrees or more is required. On the other hand, in order to deal with the error of the curvature of the rectangular column and the error of the V groove processing, the above 90 / n
Although it is better to be larger than 110 / n degrees, it is preferable to set it to 110 / n degrees or less because the gap when bending exceeds 110 / n degrees as a whole. On the other hand, the angle of the V groove is theoretically required to be 14.2 degrees or less so that no dent is formed on the outer surface of the backing material when it is bent as described above. 1 if the number of V-grooves is 8 when the upper limit of the angle of V-grooves is 110 / n
It is 3.7 degrees, which satisfies this condition.

The procedure for using this backing steel plate will be described in the case where there are two V-groove groups. First, as shown in FIG. 9 at the steel frame processing site, first bend the backing metal 11 into a channel shape by hand or the like. , Insert inside the square column so that it is almost along the inner surface of the square column. Next, a part of the channel-shaped backing steel plate is fixed to the corner column with a vise, and then the corner of the backing steel plate is easily broken by hitting the corner with a hammer. Can follow the inner surface.

If one backing steel plate can be bent into a channel shape and can be fitted along the inner surface of the corner column, then another backing steel plate is prepared, and the other side of the corner column is fitted along the same procedure. Let At this time, if there is a difference in the length from each lengthwise end of the backing steel plate to the first V groove, one of the channel-bent portions is long, so two backing sheets are used. It is possible to adjust the dimensions by cutting the respective end portions 12 so that the end portions of the steel sheet for use are abutted against each other. A backing plate is formed on the entire length of the inner surface of the rectangular column, a predetermined welding route interval is secured, and the backing plate is temporarily welded.

Even when four groups of V-grooves are provided on the entire length of the backing steel plate, the backing metal 13 may be bent as shown in FIG. 10 by bending in the same manner as above. At this time, if the lengths from the respective lengthwise ends of the backing steel plate to the first V groove are provided differently and one of them is made sufficiently long, the extra portion 1
By cutting 4, it is possible to exactly match the inner dimensions of the square column. In addition, V in one backing steel plate
The number of the groove groups is not limited to 2 or 4 described above, and one of the grooves is used as shown in FIG.
It can be set to 5. In this case, a short backing steel plate of the present invention having V grooves as shown in this figure may be used, and a straight backing plate 16 of a steel plate may be used between them.

[0039]

EXAMPLE A backing steel sheet was manufactured by using steel sheets having thicknesses of 6 mm and 9 mm and a width of 25 mm and changing the number and shape of V-grooves and tested. The radius of curvature inside the target corner column is 23 mm, and the arc length of the quadrant of the curved portion is 36 mm. Table 1 shows the test conditions and results.

[0040]

[Table 1]

As shown in this table, under the conditions of the present invention, the residual thickness t _b of the V groove portion is 2 mm, 3 mm and 4 mm.
I did it in. When the backing steel plate is bent, the length k of the portion to be applied to the curved surface inside the corner of the corner column is (1)
According to the equation (2), as the remaining thickness of the V groove portion increases, it becomes 33.0 mm, 31.4 mm, 30.
It becomes as short as 0 mm. For the pitch p of the V groove,
It is divided by the number of grooves, and the arrangement of V grooves is as shown in FIG. Further, the number 4 is a section in which a group of V grooves is provided so as to correspond to the dimensional error of the rectangular column, is made longer than the length of k, and accordingly the number of V grooves is increased by two on each side. In these backing steel sheets under the conditions of the present invention, no dent was formed when bent, and good results were obtained.

On the other hand, the comparative examples Nos. 12 and 13 had a small number of V-grooves, so that when they were bent, a recess was formed on the outside. Further, in the case of the number 14, the total angle of the group of V grooves is smaller than 90 degrees, so even if it is bent until the V grooves are all closed, it cannot reach a right angle, and if it is attempted to bend to a right angle, a large force must be forcibly applied. It was On the other hand, in No. 15, the total angle of the group of V-grooves is 126 degrees, which exceeds 110 degrees, which is the range of the present invention. There has occurred. Further, in Comparative Example No. 16, the remaining thickness of the V groove portion was too thick as 4.5 mm, and it was quite difficult to bend even if a vise was used.

[0043]

As is apparent from the above description, the present invention relates to a steel plate used as a backing metal for a joint when a column by a square column is manufactured by using a welding joint method.
The theoretical consideration and experiment were repeated on the function of the welding backing steel sheet with grooves, and the optimum one was found by paying attention to the law concerning the number, size, and shape of the grooves. As a result, it is possible to obtain an excellent quality effect at a minimum cost, which is not obtained from the range of the conventional idea of simply providing a groove for easy bending. By using the grooved steel plate shown in the present invention, a welding backing plate for a rectangular column can be formed very easily, and good quality welding can be ensured, which is useful for ensuring the quality of a steel frame structure and improving the economical efficiency. Is.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a steel plate for welding backing of the present invention.

FIG. 2 is a diagram showing an example of how to use a corner column.

FIG. 3 is a sectional view of a welded portion between a square column and a diaphragm steel plate.

FIG. 4 is a diagram illustrating a bent portion of a conventional grooved steel plate for backing.

FIG. 5 is a diagram for explaining the distance between groups of V grooves, (a) is a backing steel plate, and (b) is a square column.

FIG. 6 is a diagram illustrating a calculation method of a force required to bend a backing steel plate.

FIG. 7 is a diagram illustrating a method of calculating a deformation state when a backing steel plate is bent, (a) showing a state before bending and (b) showing a state after bending.

FIG. 8 is a diagram for explaining a calculation method for determining the interval between the V grooves of the backing steel sheet according to the present invention. FIG.
(B) shows a state after bending

FIG. 9 is a diagram showing a method of applying the steel sheet for welding backing of the present invention.

FIG. 10 is a diagram showing a method of applying the steel sheet for welding backing of the present invention.

FIG. 11 is a diagram showing a method of applying the steel sheet for welding backing of the present invention.

[Explanation of symbols]

 1 Backing Metal 2 Square Column 3 Diaphragm Steel Plate 4 Beam 5 Steel Plate for Backing 6 V Groove 7 Stress Distribution 8 Plastic Deformation Part 9 Flat Surface Connecting V-groove Bottom 10 Curved Surface Connecting V-groove Bottom 11, 13 , 15 backing metal 16 straight steel backing metal 20 grooved part 21 dent

Claims (4)

[Claims] 1. In a backing steel plate provided in a straight state for butt welding of a rectangular column and used by bending according to the inner dimension of the rectangular column, it should be applied to the curved surface inside the corner of each rectangular column. The number of groups in the part is 8 or more 10
A group of V grooves or less is provided, and the depth of the V grooves is a value obtained by subtracting 1.7 to 4 mm from the plate thickness of the backing steel plate, and
A steel plate for welding backing of a square column, wherein the groove angle is 90 / n degrees or more and 110 / n degrees or less, where n is the number of V grooves in a group. 2. The length of a portion of the group of at least one V-groove according to claim 1, which is not more than two V-grooves on one side or both sides of each group, which is to be applied to the curved surface inside the corner of the corner column. The steel plate for welding backing of a square column according to claim 1, wherein the steel plate is added over the range. 3. The length of the portion to be applied to the curved surface inside the corner of the square column is such that the radius of curvature inside the corner of the square column is r, and the remaining thickness of the backing steel plate at the V groove portion. When the the _{t b, π (r-t} b) / 2 welding backing steel sheet for corner column according to claim 1 or 2, characterized in that a. 4. A group of V-grooves is provided at two or four positions along the entire length of the backing steel plate, and the length from each lengthwise end of the backing steel plate to the first V-groove is different. The steel plate for welding backing of a square column according to any one of claims 1 to 3, further comprising: