JP2017115336A - Lip H-shaped steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture lip H-shaped steel at equal cost to H-shaped steel, by strengthening a value Zy of a section modulus around the weak axis to a similar standard to its Zx around the strong axis, without increasing-decreasing the cross-sectional area in the H-shaped steel used for a column.SOLUTION: A flange thickness is reduced still in the same cross-sectional area to ordinary H-shaped steel, and a projection is provided on a flange pointed end by that extent, and lip H-shaped steel is formed. A value of Zy/Zx is increased to 1/2 or more from about 1/3. Similarly, the flange thickness of the H-shaped steel having the same cross-sectional area is reduced to an ordinary square steel pipe column, and lip H-shaped steel is formed by providing the projection on the flange pointed end by that extent, and respective part dimensions are properly set, and the value of Zy and Zx is set equal to a section modulus Z of a square steel pipe. The lip H-shaped steel forms a lip by bending a flange outer edge part in the same efficiency as usual by post-installing a bending processing machine composed of a new fixing buckling restriction block and a pair of draft rolls in an existing hot-rolling line.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lip H-section steel having excellent cross-sectional bending performance in an H-section steel used as a column material or a beam material of a steel structure building.

  A heavy H-section steel is often used for large steel structures. In ordinary H-shaped steel, the bending strength (related to the section modulus Z) and the bending rigidity (related to the secondary moment I of the section) are around the strong axis (neutral axis (XX in FIG. 1) parallel to both flanges) and the weak axis ( It differs greatly around the neutral axis (YY in FIG. 1) parallel to the web, and in the case of equilateral sides, Zy is about 1/3 of Zx.

When used as a pillar material, it is often a brace structure in which the strong axis direction (flange surface) having a high yield strength is reinforced with a ramen structure and the weak axis direction is reinforced with braces. The brace structure greatly restricts the installation of the window. When giving priority to windows, the columnar material is not an H-shaped steel, but a square steel pipe or a circular steel pipe is used to form a full-frame ramen structure. To increase the application of H-section steel as a column material, the weak shaft strength must be greatly improved.
When H-shaped steel is used as a beam material, it is assembled so that the flange surface is horizontal and can withstand a large load.

There are also problems with square or circular steel pipes for pillars.
1) Since the steel pipe is manufactured by cold bending a hot-rolled thick plate into a tube and closing it by welding, the cost is considerably higher than that of H-shaped steel for mass production of hot-rolled steel.
2) With H-shaped steel, it is easy to extend and assemble the shaft by “holding bolt connection”, but with steel pipes, it is difficult to handle and some work is required.
3) In H-section steel, the space between both flanges has utility value for piping and wiring, but in steel pipe, a separate space must be provided.

On the other hand, lightweight H-section steel that reduces the amount of steel is used for houses and lightweight warehouses. The shape steel is assembled into an H shape by welding a hot-rolled or cold-rolled thin steel strip several mm thick.
In particular, as described in Non-Patent Document 1, a lip lightweight H-shaped steel (FIG. 3 in the literature, FIG. 4 in the present application drawing) in which the flange portion is formed into a groove shape by cold rolling or the like in advance is another H-shaped steel. It has characteristics not found in the standard. In this case, it is presumed that by setting the dimensions appropriately, it is possible to achieve a bending performance equivalent to both axes as in the case of a square steel pipe. For more difficult buckling problems, the H-shaped with lips is clearly more advantageous than the H-shaped, and is actually used a lot.

If the above characteristics of the lightweight lip H-section steel can be applied to a normal H-section steel, it is more convenient for the expansion of the application range and the cost advantage, but it has not yet been seen because of many manufacturing problems.
1) It is extremely difficult to form a lip in the existing hot-rolled H-section steel rolling line due to the increase of the hole shape and the relationship between the roll and the roll drive shaft. It is even more difficult to make the lip thickness larger than the flange thickness in order to improve performance. There is no processing machine that can bend the flange immediately after hot rolling or a hot rolling line with a bending process.
2) Lip formation is easy with the welding assembly method. The welding point of the welded H-section steel is usually two points, but the method of attaching the lip to the H-section steel has four points, and when assembling seven plates, the number of points becomes six, which increases the cost problem.
3) If the material thick plate that forms the flange like the lightweight lip H-shaped steel is pre-grooved in the welding assembly, the welding point is maintained at two points and the cost burden is reduced. Thickness cannot be optimized (same).

Patent Document 1 (preceding example) discloses a method for compensating for the lack of proof stress around the weak axis, which is a problem of H-section steel. According to this, the thickness of the flange central part is reduced, and both outer edges of the flange are made thicker, and the section modulus Zy around the weak axis is increased while maintaining the section modulus Zx around the strong axis substantially.
It has the same cross-sectional area as the original H-shaped steel (compression strength is equivalent), and the value of Zy / Zx is exemplified to be improved from 0.34 to a maximum of 0.46.

The problems of the above H-section steel are listed.
1) Although the Zy value has improved, it is still insufficient to eliminate braces.
2) While it is easy to extend and assemble the columns and beams by “patent bolt connection”, which is one of the features of H-section steel, the improvement produces a step on the outer surface of the flange. Requires a board.

Ferrum Vol.20 (2015) No.11, p19 “Japanese Industrial Standard for H-Shaped Steel and Its Structural Performance”

JP2002-180597

In ordinary H-shaped steel, bending strength and bending rigidity differ greatly in the direction of the flange and web. Therefore, when used as a column material, one is easy to cope with the ramen structure, but the other is often a brace structure (with built-in windows) due to insufficient strength. It is difficult). In order to compete with the widely used rectangular and round steel pipes, it is essential to improve the cross-sectional performance around the weak axis.
In the prior example in which the section modulus ratio Zy / Zx is improved by setting the flange thickness to two steps, the ratio is less than 0.5, which is insufficient for removing the braces. In addition, there is a problem in that a different thickness plate is required for bolt joining.
Steel pipe columns have no problem of strength anisotropy, but they are expensive, difficult to join with bolts, and difficult to use the space in the columns. In addition, the cost is considerably higher than that of H-section steel.

  The H-section steel of the present invention has the same strong axis section coefficient Zx and the weak axis section coefficient Zy of 0.5 or more of Zx at the same unit weight (kg / m) as the steel tube column so that it can be easily replaced with the steel tube column. In addition, the problem to be solved is to make the manufacturing cost smaller than that of the steel pipe column while improving it equally.

  The first invention is an H-section steel having a cross-sectional shape similar to that of a lightweight lip H-section steel, has the same cross-sectional area as a normal H-section steel, has a lip thickness equal to or greater than the flange thickness, flange width, lip width and web By appropriately selecting the width, the section modulus Zx around the strong axis is set to the same level as that of the normal H-shaped steel, and the section modulus Zy around the weak axis is 0.5 to 1.0 of the section modulus Zx around the strong axis. The lip H-section steel is characterized as follows.

  The second invention is an H-section steel having the same cross-sectional shape as the lightweight lip H-section steel, has the same cross-sectional area as a rectangular steel pipe column with a uniform wall thickness, the lip thickness is equal to or greater than the flange thickness, and the flange width and lip By appropriately selecting the width and web width, the section modulus Zx around the strong axis is set to the same level as that of the square steel pipe column, and the section coefficient Zy around the weak axis is set to 0.8 to 1.0 of Zx. It is a lip H-section steel characterized by this.

  According to a third aspect of the present invention, a pair of channel steels facing each other is used as a flange, and one wide flat steel is used as a web for welding and assembling into an H shape, whereby the side walls of the channel steel are used as lips. The lip H-section steel described in the first invention or the second invention.

  According to a fourth aspect of the present invention, after the end of hot rolling of H-section steel, the flange central portion is sandwiched with a gap by a buckling restraint guide fixedly arranged in parallel and close to the inner and outer surfaces of the center portion of the flange, but the outer edge portion protrudes. The lip H-section steel according to the first invention or the second invention, wherein the protruding portion is squeezed by a roll and continuously bent inward to form a lip.

  As the definition of predicate, “same level” is preferably the same as the original, but if there is a small difference, there is no practical problem, and there is a calculation difference caused by the difference in the welded area and the corner area. A difference of ± 5% is allowed.

1) Compared with the normal H-section steel used for steel columns, the lip H-section steel of the present invention has the same compressive strength with the same cross-sectional area, the same strong axis bending strength, and the weak axis strength of the lip Since the effect is greatly improved, the condition that the brace is not required is relaxed compared to the preceding different thickness H-shaped steel, and the window can be easily incorporated.
2) Compared to normal square steel pipe columns, the lip H-section steel of the present invention has equivalent compressive strength due to the same cross-sectional area, and can be replaced with steel pipe columns because it has bending strength equivalent to both axes by appropriate dimensional design. .
In addition, the convenience of the H-section steel that is not in the steel pipe column is maintained. a) Bolt joining is easy. b) The space between the flanges can be used for piping and wiring.
3) The lip H-section steel of the present invention can be manufactured by welding assembly using a hot-rolled groove section steel as a raw material, and can have a cost advantage over a steel pipe column.
4) Since the lip H-section steel of the present invention can be formed by a relatively simple bending machine that is connected directly to the existing H-section steel hot-rolling line, it is almost the same as a normal hot-rolled H-section steel. It can be manufactured at low cost, and is more cost-effective than square steel pipe columns and round steel pipe columns.

The cross-sectional shape of the lip H-section steel of the present invention is shown in comparison with a conventional H-section steel. The cross-sectional shape of the lip H-section steel of the present invention is shown in comparison with a conventional square steel pipe column. The groove steel of the member used as the flange of the lip H-section steel of this invention is illustrated. The cross-sectional shape of a lightweight lip H-section steel is shown. It is the schematic front view A and side view B of the bending machine which forms a lip.

  FIG. 1a shows a cross section of a conventional H-section steel used for a column, FIG. 1b shows a cross section of a lip H-section steel of the present invention, and FIG. 1 is a web, 2 is a flange 5 is a lip. Unlike normal H-section steel, different thickness flange H-section steel and lip H-section steel have the same cross-sectional area, so that the amount of steel is the same and the compressive strength is the same.

Conventional H-section steel is manufactured by hot rolling or by welding and assembling three steel sheets. In the H-section steel shown in FIG. The section modulus Zy around the weak axis YY is about 1/3 of the section modulus Zx around the strong axis XX.
In the different thickness flange H-shaped steel, the flange width central portion 4 is thinned and the flange width outer edge portion 3 is thickened accordingly. Therefore, a portion with a large bending strain is increased, and Zy is strengthened while maintaining Zx. . It is expected that the applicable range will expand as a pillar material. It is noted that the flange H-shaped steel with different thickness is easily manufactured by the existing hot rolling line.

  In the H-section steel of the present invention shown in FIG. 1c, the entire flange is thinned, and a thick protrusion (lip 5) is newly provided in parallel with the web 1 at the end of the flange, thereby forming a lip H-section steel. By “appropriate dimension setting”, Zx is usually equivalent to H-section steel, and Zy can be further strengthened. If the Zy / Zx ratio is 0.5 or more, the adoption of the ramen structure becomes easier than the former.

FIG. 2a shows a cross section of a widely used rectangular steel pipe column 6, and FIG. 2b shows a cross section of a lip H-section steel of the present invention. Each has the same cross-sectional area, so the amount of steel is the same and the compressive strength is the same.
Since the former is square, it has the same cross-sectional performance in the X and Y directions. In the latter case, Zx = Zy can be set by “appropriate dimension setting” and can be made equal to the former Z. Therefore, it can be replaced with a square steel pipe in terms of strength.

  It can be understood from the principle formula that it is effective to increase the value of the weak-axis section modulus Zy farther from the neutral axis and thicker. Therefore, it is desirable to make the lip thickness larger than the flange thickness. If it is the same or less, the lip width must be increased accordingly, and the Zx value becomes smaller. However, the Zy value is unchanged. Further, when the lip width is increased, the H-shaped opening width is reduced, and it is difficult to perform construction for piping and wiring in the opening.

The lip H-section steel of the present invention can be easily manufactured by welding assembly and is more cost-effective than a steel pipe column.
FIG. 3 shows a cross-sectional shape of a member constituting the flange portion during welding assembly. Since a suitably thick channel steel is used, it can be manufactured at a lower cost than ordinary welded H-section steel.

A manufacturing method of the lip H-section steel having the most cost advantage will be described. First, an H-shaped steel with a different thickness flange having a larger flange width is formed by an existing hot rolling line by the method shown in the preceding example. A bending machine for forming a lip is provided following the line, and the outer edge of the flange is bent at the root of the thick part by the bending machine to form a lip.
FIG. 5 shows an example of a new bending machine, FIG. 5A is a front view, and FIG. 5B is a side view. The bending machine squeezes the flange restraining block 11 fixed over the line and the flanges 13 and 13 ′ of the H-shaped steel 12 passing through the block while running through the line, thereby reducing the flange outer edge (thick wall). And rolls 14, 14 'for bending the portions 19, 19').
The buckling restraint block 11 has two left and right outer restraint guides 15 and 15 'arranged in parallel and close to the outer surface of the flange, and two upper and lower inner face restraint guides 16 and 16' arranged in parallel and close to the inner surface of the flange. And connecting bodies 17 and 17 'for connecting the four guides.

  The width of the outer surface restraining guides 15 and 15 'is the same as that of the thin portions 18 and 18' at the center of the flange. If the height of the inner surface restraining guides 16 and 16 'from the web is slightly lower than that of the outer surface restraining guides 15 and 15', the inner restraining guides 16 and 16 'are easily bent. The thin flange portions 18 and 18 'are sandwiched by the inner and outer restraint guides with a gap, and the thick flange portions 19 and 19' of the flange protrude from the guides. The thick wall portions 19 and 19 'of the flange are pressed down by the rolls 14 and 14' and bent inward to form lips 20 and 20 '.

  Since it is produced in the same efficiency and almost the same process as mass-produced H-section steel, the cost is almost the same, and it is clearly more cost-effective than the steel pipe column by cold forming + welding of thick plates.

  Table 1 shows numerical values calculated based on specific dimensions for the shape of FIG. 1 and the shape of FIG. 2 as examples of “appropriate dimension setting”.

For a 400 mm square H-section steel (FIG. 1a), the Zy / Zx value from 0.34 to 0.40 in the same shape preceding example (FIG. 1b) is 0. In the present invention (FIG. 1c, outer diameter 400 mm × 500 mm) Improve to 74. The reason why the value of Zy / Zx is specified to be 0.5 or more is to make it clear that all of the preceding examples are less than 0.5, which is superior to the preceding examples and is advantageous for omitting the m brace.
The reason for specifying 1.0 or less is that no improvement equal to or higher than that is required.

Zy and Zx of the lip H-section steel of the present invention (FIG. 2e, 360 × 520) are the same as the prisms for a 400 mm square prism (FIG. 2d).
The reason why the value of Zy / Zx is specified as 0.8 or more is substantially the same as Zy and Zx, and there is no problem in use. However, in order to facilitate manufacture, some tolerance for azimuth is considered. There is.

  It can be seen from Table 1 that the same performance as that of the prism can be obtained by properly setting the lip height C even in the third aspect of the present invention in which the lip thickness is twice the flange thickness.

DESCRIPTION OF SYMBOLS 1; Web 2; Flange 3; Flange width center part 4; Flange width outer edge part 5; Lip 6; Square steel pipe column XX; Strong axis YY; Weak axis 11; Buckling restraint block 12; Flange 14, 14 'roll 15, 15'; outer surface restraint guide 16, 16 '; inner surface restraint guide 17, 17'; coupling body 18, 18 '; thin wall portion 19, 19'; thick wall portion 20, 20 ';

Claims (4)

  H-section steel with the same cross-sectional shape as lightweight lip H-section steel, with the same cross-sectional area as normal H-section steel, with lip thickness equal to or greater than flange thickness, and appropriate selection of flange width, lip width, and web width Thus, the section modulus Zx around the strong axis is set to the same level as that of the normal H-shaped steel, and the section modulus Zy around the weak axis is set to 0.5 to 1.0 of the section modulus Zx around the strong axis. Characteristic lip H-section steel.   H-section steel with the same cross-sectional shape as the lightweight lip H-section steel, which has the same cross-sectional area as a square steel tube column with uniform wall thickness, the lip thickness is greater than the flange thickness, and the flange width, lip width and web width are By appropriately selecting, the section modulus Zx around the strong axis is set to the same level as that of the square steel pipe column, and the section factor Zy around the weak axis is set to 0.8 to 1.0 of the Zx. Lip H-section steel.   The pair of channel steels facing each other as a flange and a wide flat steel as a web are welded and assembled into an H shape to form a side wall of the channel steel as a lip. The lip H-section steel according to Item 2.   In the hot rolling of H-shaped steel, after the end of rolling, the central part of the flange is sandwiched with a gap by a buckling restraint guide fixed in parallel with the inner and outer surfaces of the central part of the flange, but the outer edge part protrudes. The lip H-section steel according to claim 1 or 2, wherein the lip is formed by rolling down a roll and continuously bending inward.

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