JP4724591B2 - Buckling stiffening structure for box-shaped thin sheet member - Google Patents

Description

  The present invention relates to a buckling stiffening structure for a box-shaped cross-section thin plate member, for example, as a rod-shaped member such as a vertical frame member and a horizontal frame member made of a thin lightweight plate steel used in steel houses, houses, factory buildings, and the like. The present invention relates to a buckling stiffening structure for a suitable box-shaped thin plate member.

  As a frame structure in a conventional steel house, the structure shown in FIG. 23 is common. In the figure, the pillars, beams, joists and other vertical and horizontal frames built on the fabric foundation are mainly composed of a single thin steel plate with a thickness of 0.8 to 1.6 mm, which enhances its strength. Therefore, the one formed by bending into a groove shape by roll forming (simply called groove steel) is used.

  In FIG. 23, a plurality of pillars 2, corner pillars 3, and a vertical frame 4 constituting the first floor are erected from a lower frame runner 1 fixed by anchor bolts on a fabric foundation (not shown). At the upper ends of the pillar 2, corner pillar 3, and vertical frame 4, a head connection, an upper frame runner 5, and the like are provided. Moreover, in order to form the window opening part 6 for 1st floors, the lintel 7 and the lintel support 8 are provided. A roof truss 13 is attached to the upper frame runner 5 via a head joint 10, a stopper 11, a tilt stopper, a gusset plate 12, and a brace 9. The lower truss material (that is, the ceiling joist) 14 of the roof truss 13 rises a frame 15 of the house hut, and the upper chord material of the roof truss 13 includes a reinforcing rack 13a, a flutter 16 and a head stopper 17 and the like. Is provided.

  Conventionally, in a thin lightweight steel structure such as a steel house, a cross-sectional structure based on a grooved steel 18 with a lip as shown in FIGS. 24A and 24B has been put into practical use. Further, when the lip-shaped grooved steel 18 as described above is used as a vertical frame member, it is often used as an assembled H-shaped steel 19 having an H-shaped cross-sectional structure as shown in FIG. .

  In FIG. 24 (B), the webs 21 of the two channel steels 18 are abutted back to back, and both the channel steels 18 are joined by driving through the webs 21 and driving a drill screw 22. As a vertical member including the column 2 or the corner column 3 or the vertical frame member in FIG. 23, or an inclined member such as a beam or a truss member or a horizontal member including the horizontal frame member, the buckling strength of the channel steel is improved. It is.

  As the development of vertical frame materials (and vertical members) or horizontal frame materials (and horizontal members) used for thin steel lightweight steel buildings 23 on the first floor or the second floor or more of a steel house or the like as shown in FIG. 23 progresses. In the cross section of FIG. 24 (B), the lip-shaped grooved steel 18 is exposed to the labor required for assembling a large number of drill screws 22, the outer groove of the assembled H-shaped steel member 19, the drill screw 22 or the like is exposed. As a result, problems in the appearance of the member have become apparent, and the need for a rectangular closed cross-section member 24 as shown in FIG.

  The closed cross-section member 24 shown in FIG. 25 (A) was formed by bending a strip-shaped thin steel plate into a box-shaped cross-section having a closed annular cross section composed of four sides 25 and a right-angled corner portion 26 by roll forming. Bar-shaped box-shaped thin plate member such as a vertical frame member of a column member (square steel) 1 or a horizontal frame member including an inclined beam such as a roof truss 13 by seaming both ends of a strip-shaped thin steel plate with a caulking portion 27 28 is constituted.

However, in the box-shaped cross-section member (square steel) 28 in FIG. 25 (A), each corner portion 26 is a corner portion that is smaller than twice the thin plate thickness t. whereas the influence of the width of a small outer width b, as shown in FIG. 24 (B), the assembly H-beam member 19 of the same outer shape width b, and Mizokatachiko 18 When two are used, the assembly is as shown in FIG. 24 (B). In the assembled H-shaped steel member 19 configured by combining two channel steels 18, the flange portions of the individual channel steels 18 are provided. In the box-shaped cross-sectional form of FIG. 25A in which the width b / 2 full width of 29 becomes an effective width and becomes a dimension b that is twice the width of the flange portion 29 of the channel steel 18, Since the plate bending rigidity to the out-of-plane of each side 25 in the box-shaped cross-sectional form is reduced, considering the local buckling, the entire width dimension You often can not be incorporated on the design as effective dimension.

As described above, in the box-shaped cross-section thin plate member 28 formed by bending one thin plate member, the effective dimension width is smaller than the outer width dimension b in calculating the bending rigidity of the box-shaped cross-section member. Therefore, the ratio (width-thickness ratio) between the plate thickness t and the outer width dimension b increases as a large factor. (A web portion 21 of the assembled H-shaped steel member 19 in FIG. 24 (B), the vertical portions of the right and left in FIG. 25 box-shaped cross section type thin plate members 28 (A) corresponding thereto, substantially the same effective size width become.)

  Accordingly, the assembled H-shaped steel member 19 has a total width dimension b of the width b / 2 of each flange 29, whereas the box-shaped cross-section thin plate member 28 having a large side dimension is smaller than the dimension b. Therefore, since elements having a large width-thickness ratio (t / b) increase, the ratio of the effective cross-sectional area (Ae) to the total cross-sectional area (A) of the box-shaped cross-section thin plate member 28 (the cross-sectional effective ratio ρ = Ae / A) becomes smaller, and a new problem has arisen in that the strength per unit weight of the member decreases. In addition, in general steel materials, the plate thickness dimension can be set appropriately large, so that the above-described problems do not occur, and a box-shaped cross-section type with a thin plate member having a thickness t of 0.8 mm to 1.6 mm This is a problem peculiar to the thin plate member 28.

In order to solve the problem of reduction in the effective sectional area (Ae), a stiffening rib 31 may be provided in the middle part of the plate element 30 constituting each side 25 as shown in FIG. Patent Documents 1 and 2 (Japanese Patent Laid-Open No. 2001-152607), or a method of improving the effective section ratio ρ by corrugating the plate element 30 as shown in FIG. 25 (c). It has been proposed. In the case of the structure shown in FIGS. 25B and 25C, (1) the stiffening rib or corrugated plate may be an obstacle when the drill screw is driven, or (2) the stiffening rib 31 or corrugated plate. Although there are drawbacks such as an increase in manufacturing cost for molding 20, the rigidity of the plate-shaped cross-section thin plate member 28 as a whole is improved by increasing the rigidity of the plate elements 30 on each side 25 by adopting the structure as described above. The stiffening structure against buckling can be obtained.
JP 2001-152607 A JP 2001-329656 A

  In the field of thin plate lightweight steel construction using the box-shaped cross-section thin plate member 28 as described above, the box-shaped cross-section thin plate member 28 having a square cross section shown in FIG. Is defined to be twice the plate thickness t of the thin plate member (R = 2t). One reason is that the corner portion 26 of the box-shaped cross-section thin plate member 28 is semicircularly bent according to a semicircular bent portion that is greatly bent in an arc shape exceeding 2t, which is twice the plate thickness t. Since the section (arc-shaped section 32) is closer to the center of the member and the sectional moment of the entire member is reduced, the corner is actively considered as a stiffening structure against buckling. There wasn't.

  Since there is a basic design philosophy that the moment of inertia of the entire member is reduced as described above, in the field of thin plate lightweight steel construction, the corner portion 26 of the box-shaped cross-section thin plate member 28 is not shaped like a box. The formation of a large arc-shaped stiffening portion at the corner portion of the cross-sectional thin plate member 28 and the dimensions of the arc-shaped stiffening portion at the corner portion have not been considered by deep technical digging. .

As the inventor increases the arc-shaped or linear stiffening portion at the corner, the bending buckling strength of the entire member, that is, the moment of inertia of the cross section tends to decrease, and the arc-shaped or linear Paying attention to the characteristics of the change in the effective cross-sectional area Ae when the width dimension of the stiffening section is changed, the dimension of the stiffening section at the corner, the allowable compressive stress Fcr (N / mm ² ), and the effective Focusing on the strength of the final member from the relationship with the cross-sectional area Ae (mm ² ), the allowable compressive strength (Ae · Fcr) of the final member, that is, (effective cross-sectional area Ae) × (allowable compressive stress degree) Fcr) is known to draw a chevron diagram depending on the size of the corner stiffening portion, and the box stiffening shape is determined by setting the size of the corner stiffening portion within a predetermined range. The present invention finds that the bending buckling rigidity of a thin plate member can be efficiently increased, and the present invention It was completed.

An object of the present invention is to provide a buckling stiffening structure for a box-shaped cross-section thin plate member that can advantageously solve the above-described conventional problems.
Another object of the present invention is to provide a buckling stiffening structure for a box-shaped cross-section thin plate member that can be applied to the conventional box-shaped cross-section thin plate member. Here, the box-shaped cross-section thin plate member is a thin plate member having a thickness of 0.8 mm to 1.6 mm, such as a steel house, a house, a column member of a factory building, and a thin plate other than a house such as a leg frame of an OA desk. The same structure can be applied.

In order to solve the above-mentioned problem advantageously, in the buckling stiffening structure of the box-shaped cross-section thin plate member of the first invention, the thickness of the plate-shaped cross-section thin plate member is 0.4 mm to A 1.6 mm box-shaped cross-section thin plate member is formed by bending a thin steel plate into a box-shaped cross-sectional shape to form a corner stiffening portion that connects each side and adjacent sides to each other . The cross-sectional thin plate member has a closed cross-sectional shape of any one of six to octagons as a whole by forming a corner stiffening portion at each corner in at least one diagonal direction in the square cross-sectional shape, The part stiffening part has a linear shape or an arc shape on the outer side of the member or an arc shape on the inner side of the member, and the outer width dimension b of the box-shaped cross-section thin plate member is set so as to satisfy the following expression (1). a box-section-type thin plate members that, each corner stiffening portion, direction parallel to the side to be connected thereto The width dimension D is more than twice the plate thickness of the thin plate member and is not more than 1/3 of the external width dimension b of the two sides connected at the corner portion, or of the two sides connected at the corner portion The corner stiffening portion having a dimension equal to or less than 1/3 of the outer width dimension of any one of the shorter short sides is defined, and the width D of the corner stiffening portion is expressed by the following relational expressions (2) and (3): A value satisfying both conditions and having a small upper limit value is set as the width dimension D.
b> 740t / (√F) (1)
2t <D ≦ 2.0 ([b / 2] − [370 t / (√F)]) (2)
2t <D ≦ b / ((√2) +2)) (3)
F: Design standard strength (N / mm ² )
t: Thickness (mm) of the box-shaped cross-section thin plate member
In the buckling stiffening structure for the box-shaped cross-section thin plate member according to the second invention, the box-shaped cross-section thin plate member having a thickness of 0.4 mm to 1.6 mm is provided. Is formed by bending a thin steel plate into a box-shaped cross-sectional shape to form a corner stiffening portion for connecting each side and adjacent sides, and the box-shaped cross-sectional thin plate member has a square cross-sectional shape. A corner stiffening portion is formed at each corner in the diagonal direction to form an octagonal closed cross-sectional shape as a whole, and each corner stiffening portion is linear or outside the member in an arc shape or inside the member And a box-shaped cross-section thin plate member in which the outer width b of the box-shaped cross-section thin plate member is set so as to satisfy the following formula (1). The portion has a width dimension D in the direction parallel to the side connected to it that is more than twice the plate thickness of the thin plate member, and The dimension was set to 1/3 or less of the outer width b of the two sides to be connected at the knurled portion, or to one third or less of the outer width of the shorter side of the two sides to be connected at the corner portion. A corner stiffening portion is set, and the width D of the corner stiffening portion satisfies both conditions of the following relational expressions (2) and (3), and a value having a small upper limit value is set as the width dimension D. It is characterized by being.
b> 740t / (√F) (1)
2t <D ≦ 2.0 ([b / 2] − [370 t / (√F)]) (2)
2t <D ≦ b / ((√2) +2)) (3)
F: Design standard strength (N / mm ² )
t: Thickness (mm) of the box-shaped cross-section thin plate member

According to a third invention, in the buckling stiffening structure of the box-shaped cross-section thin plate member according to the first or second invention, the box-shaped cross-section thin plate member is configured by combining a plurality of thin steel plate members. And

In the buckling stiffening structure of these box-shaped cross-section thin plate members, the at least one corner stiffening portion has the same width dimension in the direction parallel to each side connected thereto. Also good.
Further, the box-shaped cross-section thin plate member may be a closed box-shaped cross-section member or a box-shaped cross-section member with a part of the side opened as a reference form .
Further, the column member formed of a box-shaped cross-section thin plate member may be formed by means such as welding, drill screw, rivet, adhesion, etc., in addition to the method by caulking.

In the buckling stiffening structure of each box-shaped cross-section thin plate member, the dimension b ₀ between adjacent corner stiffening portions at intervals in the box-shaped cross-section thin plate member is equal to the corner stiffening portion. You may set so that the following relational expression (4) and (5) of the said width dimension D and the external width dimension b of a box-shaped cross-section thin plate member may be satisfied.
b = b ₀ + 2D (4)
b ₀ <740 t / (√F) (5)
F: Design standard strength (N / mm ² )

According to the present invention, even if the width D of the corner stiffening portion in the box-shaped cross-section thin plate member is set larger than the conventional case, the width D of the corner stiffening portion is set within a predetermined range. Thus, the effective cross-sectional area can be increased and the member strength of the box-shaped cross-section thin plate member can be increased.
Moreover, the member strength of the box-shaped cross-section thin plate member can be managed by setting the width dimension D of the corner stiffening portion to a predetermined value. Further, the present invention can be applied in the range of the plate thickness of 0.4 mm to 1.6 mm, and preferably the plate thickness of 0.8 mm to 1.6 mm.

  Next, the present invention will be described in detail based on the illustrated embodiment.

  FIG. 1 shows a first embodiment of a buckling stiffening structure for a box-shaped cross-section thin plate member according to the present invention, which is a vertical frame member made of a thin lightweight plate steel used in a steel house, a house, a factory building, and the like. 1 shows a first embodiment in which the buckling stiffening structure of the present invention is applied to a box-shaped cross-sectional thin plate member 33 suitable as a rod-shaped member such as a horizontal frame member.

  The box-shaped cross-section thin plate member is formed by bending a thin steel plate having a thickness of 0.8 to 1.6 mm into a box-shaped cross-section shape by roll forming, and seaming both ends by caulking, so that the outer shape (four sides) is 40 mm. It is formed to be ~ 120 mm. Further, a buckling stiffening structure is formed by providing a corner stiffening portion 34 at each corner portion 26 of the four sides of the box-shaped cross-section thin plate member 33 (in the figure, each corner of the four sides). Although an example in which the buckling stiffening structure is formed by the portion 26 is shown, the corner stiffening portion 34 may be provided in at least one corner portion 26).

The cross-sectional form of the box-shaped cross-section thin plate member 33 of each embodiment of the present invention is determined based on the following two viewpoints.
(A) Roll forming is performed at the four corners of the rectangular cross section so that the plate element 30 constituting each side 25 in the box-shaped cross-section thin plate member 33 does not have an invalid portion that cannot be incorporated as an effective cross-sectional area in design. Sometimes the sloped face plate or the curved face plate is integrally bent, and the four corners of the square cross-sectional form are cut off as if chamfered, the substantially octagonal cross-sectional form is the basic form, and its application form is as follows: Among the four corners of the square cross-sectional form, a pentagonal to heptagonal deformed form in which at least one corner is provided with a corner stiffening portion 34 and a part of one side 25 of the square cross-sectional form continuously in the longitudinal direction of the member It is an open, generally further variant of approximately 5-8 octagons as a whole.
(B) By making the box-shaped cross-sectional thin plate member 33 into a pentagonal to octagonal cross-sectional form in which the corner stiffening portion 34 is provided while having an octagonal cross-section as described above, a box-shaped cross-sectional type Since the sectional moment of inertia of the thin plate member 33, that is, the total bending buckling strength tends to be small, the final member strength (that is, the member allowable compressive strength, which is the product of the effective sectional area Ae and the allowable compressive stress Fcr: Focusing on Ae · Fcr), the width D in the direction parallel to the side 25 of the corner stiffening portion 34 in FIG. I have to.

The effective cross-sectional area (Ae) of the plate element 30 in the box-shaped cross-section thin plate member 33 is determined based on the following formula that defines the effective width Be shown in the thin plate lightweight section steel notification (Ministry of Land, Infrastructure, Transport and Tourism H13 No. 1641). However, it can also be calculated using the formula shown in the overseas guidelines.
The effective width Be is Be = 740 t / (√F), where t is the plate thickness (mm) of the box-shaped cross-section thin plate member 33, and F is the material yield point or design standard strength.

Next, with reference to FIG. 1, the relationship between the outer width b, the corner stiffening portion 34, and the plate thickness t of the box-shaped cross-section thin plate member 33 that is the subject of the present invention will be examined. The outer shape width dimension b of the box-shaped cross-section thin plate member 33 is to satisfy the following expression (1).
b> 740t / (√F) (1)
F: Design standard strength (N / mm ² )
t: Thickness (mm) of the box-shaped cross-section thin plate member
On the other hand , the length dimension b ₀ of the side 25 excluding the width dimension D of the corner stiffening portions 34 on both sides is set to satisfy the following conditions.
b ₀ = b−2D ≦ (740 t) / (√F) (6)
Based on the formula Be = 740 t / (√F) relating to the effective width and b ₀ = b−2D in the formula (6) , the allowable compressive strength (Ae · Fcr) of the box-shaped cross-section thin plate member 33 is maximized. The corner width dimension D (D1) as a condition to become can be expressed by the following equation.
D1 = b / 2 − [(370t) / (√F)]
As shown in FIG. 6, the allowable compression strength (Ae · Fcr) of the box-shaped cross-section thin plate member 33 can be effectively increased within the range of 2.0 times D (D1). Set to range.
D ≦ 2.0 [(b / 2) − [(370 t) / (√F)]]
Further, if the width dimension D does not exceed twice the plate thickness t (mm) of the thin plate member, the rigidity of the box-shaped cross-section thin plate member 24 cannot be increased efficiently compared to the conventional case. The width dimension D is preferably set within the range of the following equation (2).
2t <D ≦ 2.0 [(b / 2) − {(370 t) / (√F)]] (2)

Further, when the width Do of the flat plate portion of the corner protection portion 33 is larger than the width of the dimension bo between the corner stiffening portions, the out-of-plane bending rigidity of the plate at the width Do portion of the flat plate portion becomes the corner stiffening. Since there is a concern that the strength of the member may be reduced due to the smaller than the out-of-plane bending rigidity of the plate at the dimension bo between the parts, in relation to the outer width dimension b of the box-shaped cross-section thin plate member,
D ≦ b / ((√2) +2)) (3)
Need to be.
The equation (3) is obtained by substituting the value of b ₀ = b−2D when the corner portion 26 is a right angle and D ≦ b ₀ / (√2).
As described above, the width dimension D of the corner stiffening portion 33 may be set so as to satisfy both the conditions (2) and (3). That is, it is desirable that the maximum value of the corner width dimension D is equal to or less than the smaller value of the upper limit values of both the expressions (2) and (3).

Next, the performance of the box-shaped cross-sectional thin plate member 33 having an octagonal cross section as shown in FIG. 1 will be described. A box-shaped cross-sectional thin plate member 33 having a cross-sectional shape having corner stiffening portions 34 at four corners is as follows. For example, the box-shaped cross-section thin plate member 33 shown in FIG. 1 when applied to a vertical frame (column) of a house structure (member length L = 2400 mm, □ 90 mm × 90 mm, t = 1.6 mm) is assumed. , The width dimension D (mm) of the corner stiffening portion 34 at four corners, the allowable compressive stress F cr (N / mm ² ) excluding the safety factor (not considering the safety factor), and the effective cross-sectional area Ae (mm ² ) and the relationship between the member allowable compressive strength Ae · Fcr (kN), respectively, are shown in FIGS. The allowable compressive stress Fcr and the effective cross-sectional area Ae were calculated according to the above-mentioned notification. 4 to 6, the F is calculated as 280 N / mm ² as the design standard strength with reference to the Ministry of Land, Infrastructure, Transport and Tourism Notification No. 1639 in 2001, but is appropriately determined based on the yield point of the steel material. You may calculate.

FIG. 4 shows the relationship between the width dimension D of the corner stiffening portion 34 and the allowable compressive stress F cr (N / mm ² ) excluding the safety factor (without considering the safety factor). It can be seen that when the width D of the corner stiffening portion 34 is increased, the allowable compressive stress Fcr is reduced. This is because the width D of the corner stiffening portion 34 is increased. This is because the cross-sectional secondary moment I (mm ⁴ ) of the cross-sectional thin plate member 33 is small. As described above, in the conventional idea, since the allowable compressive stress Fcr calculated in this way is reduced, a cross-sectional configuration in which the width D of the corner stiffening portion 34 is increased as in the present invention is used. It has never been done.

  FIG. 5 shows the relationship between the width dimension D of the corner stiffening portion 34 and the effective sectional area Ae. It can be seen that when the width dimension D of the corner stiffening portion 34 is increased, the effective cross-sectional area Ae becomes larger at one end and, after giving a local maximum value, starts to decrease. Here, the maximum is obtained when D = 10 mm. The present invention pays attention to such an increasing / decreasing tendency of the effective sectional area Ae, and aims to obtain a box-shaped cross-section thin plate member 33 with good member performance while aiming to maximize the allowable yield strength (allowable compressive strength) of the member. It is.

FIG. 6 shows the relationship between the width D of the corner stiffening portion 34 and the allowable compressive strength Ae · F cr of the box-shaped cross-section thin plate member 33. The allowable compressive strength (Ae · F cr ) of the box-shaped thin plate member 33 is more affected by the effective cross-sectional area Ae than the allowable compressive stress Fcr, and becomes a maximum value when D = 10 mm. Compared to the plain square steel shown in A), the strength of the box-shaped cross-section thin plate member can be increased by about 16%. The allowable compressive strength (Ae · Fcr) at this time is almost the same as that of the conventional assembled H-section steel 19 shown in FIG. it can.

The result of evaluating the box-shaped cross-section thin plate member 33 having the same thickness of t = 1.2 mm by the same method as described above is as shown in FIGS. By setting the width dimension D of the stiffening portion 34 to 20 mm, the allowable compressive strength (Ae · F cr ) of the box-shaped cross-section thin plate member 33 can be maximized. In this case, FIG. The member strength of the box-shaped cross-section thin plate member 33 can be increased by about 40% compared to the square steel having the same plate thickness t = 1.2 mm shown in FIG. Further, the allowable compressive strength Ae · Fcr at this time is almost the same as that of the conventional assembled H-section steel 19 shown in FIG. it can.

The result of evaluating the box-shaped cross-section thin plate member 33 having the same thickness of t = 0.8 mm in the same manner as described above is as shown in FIG. 10, but in this case, the corner stiffening portion By setting the width dimension D of 34 to 25 mm, the allowable compressive strength (Ae · F cr ) of the box-shaped cross-section thin plate member 33 can be maximized. In this case, the same as shown in FIG. The member strength of the box-shaped cross-section thin plate member 33 can be increased by about 90% compared to the square steel having a plate thickness t = 0.8 mm. Further, the allowable compressive strength Ae · Fcr at this time is almost the same as that of the conventional assembled H-section steel 19 shown in FIG. it can.

  Furthermore, in any case, by increasing the width dimension D of the corner stiffening portion 34, each cross-sectional area A is reduced. Therefore, by providing the width dimension D of the corner stiffening portion 34, the unit weight It can be seen that the hit performance is also greatly improved. Note that the case where the width dimension D is 0 in FIGS. 4 to 9 is the form shown in FIG. In the present invention, as can be seen from the drawings shown in FIGS. 6 and 9, when the width dimension D is zero (the position of the left vertical axis), that is, more than the form shown in FIG. By increasing the width dimension D of the stiffening portion 34 and restricting it to a predetermined range, the allowable compression resistance can be further improved.

Note that when the outer width b of the box-shaped cross-section thin plate member 33 is set to 85 mm to 90 mm, for example, the dimension D of the corner stiffening portion 34 may be 3 mm to 30 mm. The width D of the stiffening portion 34 may be, for example, 3 mm to 10 mm.
When the cross-sectional shape of the corner stiffening portion 34 is a flat plate shape, when the dimension D of the corner stiffening portion 34 exceeds b / 3 of the outer width b, the corner stiffening portion 34 is obtained. Since the width dimension of the side 25 of the intermediate part excluding the width of the intermediate part becomes smaller and the rigidity of the part of the side 25 of the intermediate part may be relatively smaller than the rigidity of the corner stiffening part 34, It is desirable that the dimension D of the rigid portion 34 is not more than b / 3 of the outer width dimension b. However, the rigidity of the corner stiffening portion 34 is increased by making the thickness of the thin plate member and the cross-sectional shape (arc-shaped cross section or corrugated cross-sectional shape) of the corner stiffening portion 34 higher. Although it is possible to make the dimension D of the part stiffening part 34 slightly larger than b / 3 of the outer width dimension b, in the present invention, higher allowable compressive strength is expected than the form shown in FIG. It was set as the upper limit of the possible range.

  In the present invention, although it is a steel box-shaped cross-section thin plate member 33, the corner stiffening portion 34 is provided, so that corner portions can be eliminated in the same manner as chamfering in a wooden member, and a person can make a box-shaped cross-section thin plate. Even if it collides with the member 33, there is no risk of injury, and the design of the box-shaped cross-section thin plate member 33 is enhanced, and the high-quality feeling is enhanced while being a steel member, so that it is exposed to the indoor space. It is also possible to use the box-shaped cross-section thin plate member 33. Further, a cosmetic surface material is attached as necessary.

(Variation of deformation form of box-shaped cross-section thin plate member)
In the above-described embodiment, the form in which the linear corner stiffening portion 34 arranged so as to intersect each side 25 is provided at the four corners of the rectangular cross-sectional shape, but when implementing the present invention, At least the box-shaped cross-sectional thin plate member 33 having a closed cross-sectional shape, or the box-shaped cross-sectional thin plate member 33 having an open cross-sectional shape partially opened may be used to increase rigidity. This will be described in detail. Since the corner stiffening portion 34 and its width dimension D are the same as those in the above embodiment, the same reference numerals are given and the description thereof is omitted.

  In FIG. 2, the arcuate portion 35 having a center in the vicinity of intersecting on the extension line of each side 25 of the box-shaped cross-sectional thin plate member 33 and approaching the center of the member intersects each side 25. It is the form made into the corner part stiffening part 34 connected to. As described above, the corner stiffening portion 34 is not limited to a straight shape, and may be an arcuate corner stiffening portion 34. With such an inward arc-shaped corner stiffening portion 34, the outer shape is a special shape, so that it is possible to improve the design including design while being a steel member. However, it can also be used as a member arranged on the indoor side. Further, a cosmetic surface material is attached as necessary.

In the reference form shown in FIG. 3A, in the corner portion 26, a corner stiffening portion 34 is formed in which the radius dimension r of the arc-shaped portion 35 connected to each side 25 is set to a radius dimension not less than 2t. Yes, each side 25 connected to the corner portion 26 is smoothly connected. The radius dimension r of the arc-shaped portion 26 may exceed 2t, for example, the dimension D as in the above embodiment.

  In the form shown in FIG. 3B, the radius R of the arcuate portion 35 connected to each side 25 is made larger in the corner portion 26 than in the case of FIG. Within the range of the width dimension D, each side 25 connected to the corner portion 26 is connected so as to intersect. The radius R of the arcuate portion 26 may be greater than 2t, for example, a radius greater than the width D. When the radius dimension R is increased, the form approaches that shown in FIG.

  In addition to the forms shown in FIGS. 1 to 3, the form of the box-shaped cross-section thin plate member 33 having the corner stiffening part 34 according to the present invention can be various forms. explain. Moreover, the same code | symbol is attached | subjected to the same element and description is abbreviate | omitted.

The reference form shown in FIG. 11 is a box-shaped cross-section thin plate member 33 having an open cross-sectional shape in which the middle part of the right side 25 is opened, and other configurations are the same as those in the above-described embodiment. Thus, the form which used the intermediate part of the one side 25 in the box-shaped cross-section thin plate member 33 as the open part 36 may be sufficient. In such a form, since it is not necessary to provide a caulking part, manufacture is also easy. Moreover, it is suitable when the box-shaped cross-section thin plate member 33 is used as a column member and another beam member or the like is inserted and joined from the open portion 36.

In FIG. 12, the lateral width dimension of the box-shaped cross-sectional thin plate member 33 is set to b / 2, and the vertical width dimension is set to b. In such a rectangular form, since the lateral width dimension in the horizontal direction is as small as b / 2, the width dimension D of the corner stiffening part 34 may be a dimension close to the dimension b ₀ of the short side 25 of this part. However, the width dimension D of the corner stiffening portion 34 is preferably set to D ≦ (b / 2) / 3 = b / 6.

Further, as shown in FIG. 13, in the case where the box-shaped cross-section thin plate member 33 having the closed cross section as described above is used, the position when the caulking portion 27 is provided in order to close the cross section is as follows. What is necessary is just to make it provide in the position of the appropriate intermediate part of b. As the caulking fixing structure, for example, as shown in FIG. 13 (B), one end is folded inwardly in a U-shape, and the other end is folded outwardly in a symmetrical U-shape. In addition, a conventionally well-known structure may be used in which the U-shaped tip portions are overlapped and fixed by caulking.
In addition, the position of the caulking portion can be changed as appropriate based on construction reasons and the like. That is, it is not limited to the middle part of the outer width dimension b, and may be caulked and joined at a plurality of positions.

Further, when implementing the present invention, as shown in FIG. 14, an intermediate stiffening rib 31 having a U-shaped cross section extending in the longitudinal direction of the member may be integrally connected to the intermediate portion of the side 25, In this case, the corner stiffening portion 34 according to the present invention is provided, and the stiffening rib 31 is provided at the center of each side 25. Therefore, the rigidity of the box-shaped cross-section thin plate member 33 against buckling is further improved. Can be increased.
In this case, as shown in FIG. 18, a configuration in which the intermediate stiffening rib 31 having a U-shaped cross section and the caulking 27 are mixed may be used.
In addition, the present invention determines the cross-sectional shape of the box-shaped cross-sectional thin plate member 33 formed from a thin steel plate based on a consistent technical idea, and forms the cross-sectional shape of the box-shaped cross-sectional thin plate member 33. There is no limitation on the bonding method, bonding position, or number of bonding points. Therefore, a part of the thin steel sheet shown in FIG. 19 (both ends of the thin steel sheet in the case of illustration) is overlapped to form a joint part 37 joined by a joining means such as welding, a drill screw, a rivet, adhesion, As shown in FIG. 20 or FIG. 21, a box-shaped cross-section using a plurality of thin steel plate members is used to form a grooved steel 38 with a corner stiffening portion having a corner stiffening portion 34 formed from a thin steel plate. The thin plate member 33 and the case where there are a plurality of joint portions 37 are also included in the scope of the present invention. As described above, when the box-shaped cross-section thin plate member 33 is manufactured using a plurality of thin steel plate members, the number of parts is increased as compared with the case of manufacturing using a single thin steel plate, but there is an advantage that manufacture is easy.
In the form shown in FIG. 20, the flange 42 tip of the grooved steel 38 with corner stiffening portion is overlapped (however, the tip of the flange 42 located on the inside is bent so as to be displaced inward). In the case of the box-shaped cross-section thin plate member 33 as the joint portion 37 by the joining means, the form shown in FIG. 21 is the above-described joining by overlapping the lip 40 of the lip-shaped channel steel 39 provided with the corner stiffening portion. It is a box-shaped cross-section thin plate member 33 in the form of a joint portion 37 by means. For the corner stiffening portion 34 in the grooved steel 38 with the corner stiffening portion or the grooved steel 39 with the corner stiffening portion, the box-shaped cross-sectional thin plate having the corner stiffening portion 34 described above. This is the same as when the member 33 is manufactured.
In addition, although illustration is abbreviate | omitted, of course, you may form the box-shaped cross-section type | mold thin plate member 33 using the welding of both ends of the member formed with the thin steel plate, or fillet welding.
Further, as shown in FIG. 22, the box-shaped cross-section thin plate member 33 is filled with foaming resin such as urethane foam or other resin as a filler 41, so that the rigidity or heat insulation of the box-shaped cross-section thin plate member 33 is increased. You may make it raise property.

Further, when carrying out the present invention, depending on the performance required for the box-shaped cross-section thin plate member 33 and the place where it is used, as shown in FIG. A member having a structure to which the corner stiffening portion 34 of the present invention is applied may be used. In this case, the number of bent portions is reduced, so that the equipment cost for roll forming can be reduced. Moreover, what is necessary is just to arrange | position the side with the corner | angular part stiffening part 34 to the indoor side or the exposed side. In this viewpoint, in the embodiment shown in FIG. 16, in the form in which a corner stiffeners 34 in two places in the diagonal direction in the box-shaped cross section type thin plate 33. The reference form shown in FIG. 17A is a form in which the corner stiffening part 34 of the present invention is formed at one corner part 26 of the box-shaped cross-section thin plate member 33. FIG. 17B shows a form in which the width D of the corner stiffening portion 34 is increased and the box-shaped cross-section thin plate member 33 is octagonal.

  As described above, as a cross-sectional form of the corner stiffening portion 34, for example, as shown in FIG. 2, the cross-sectional arc shape approaches the central portion of the member and has the center of the circular arc on the outer side of the member. The corner reinforcing portion 34 may be connected so as to be refracted to each side 25, or conversely, as shown in FIG. The corner reinforcing part 34 having the center of the arc may be an arc-shaped corner stiffening part 34 that is refracted or smoothly connected to each side 25. Although not shown, these forms are combined. Further, the corner reinforcing portion 34 may be wave-shaped.

  In the above-described embodiment, a square box shape made of a square or a rectangle is used as a base, and the four corners are formed as corner stiffening portions. However, the present invention is also applicable to various square box cross-section members. be able to.

  In each of the above-described embodiments, the case where the corner stiffening portion 34 has the same dimension as the width of the corner stiffening portion D in the direction of each side 25 connected to the corner portion 26 has been described. In this case, although not shown, the width of the corner stiffening portion D in the direction of each side 25 connected to the corner portion 26 may be different. Accordingly, various modifications other than those shown are possible.

As described above, the width D of the corner stiffening portion is set to a predetermined range even if the width D of the corner stiffening portion in the box-shaped cross-section thin plate member is set larger than the conventional case. Thus, the effective sectional area can be increased and the bending buckling rigidity of the box-shaped cross-section thin plate member can be increased.
In addition, by setting the width D of the corner stiffening portion within a predetermined value range, it is possible to manage the bending buckling rigidity of the box-shaped cross-section thin plate member.

It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the first embodiment of the present invention. It is an end elevation of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the second embodiment of the present invention. (A) is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the third embodiment of the present application , and (B) is a short view showing the deformation mode. It is a diagram which shows the relationship between the width dimension D of the corner stiffening part, and the allowable compressive stress Fcr when the plate | board thickness of the plate-shaped member in the form shown in FIG. 1 is 1.6 mm. A line showing the relationship between the dimension D of the corner stiffening portion and the perforated cross-sectional area Ae at the end face of the box-shaped cross-section thin plate member when the plate thickness of the plate-shaped member in the form shown in FIG. 1 is 1.6 mm FIG. 1 shows a relationship between the width D of the corner stiffening portion and the allowable compressive strength when the plate thickness of the plate-like member in the embodiment shown in FIG. 1 is 1.6 mm. ) Satisfies the formula (2) and is a diagram when the maximum value is smaller in the formula (2). It is a diagram which shows the relationship between the width dimension D of the corner stiffening part, and the allowable compressive stress degree Fcr when the plate | board thickness of the plate-shaped member in the form shown in FIG. 1 is 1.2 mm. A line showing the relationship between the dimension D of the corner stiffening portion and the perforated cross-sectional area Ae at the end face of the box-shaped cross-section thin plate member when the plate thickness of the plate-shaped member in the form shown in FIG. 1 is 1.2 mm FIG. 1 shows the relationship between the width D of the corner stiffening portion and the allowable compressive strength when the plate thickness of the plate-like member is 1.2 mm in the form shown in FIG. It is a diagram when the formula (3) is satisfied and the maximum value is smaller in the formula (3). FIG. 1 shows the relationship between the width D of the corner stiffening portion and the allowable compressive strength when the plate thickness of the plate-like member in the form shown in FIG. 1 is 0.8 mm. It is a diagram when the maximum value is smaller in equation (3) that satisfies equation (3). It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the fourth form of the present application . It is an end elevation of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the fifth embodiment of the present invention. An end view of a buckling stiffening structure of a box-shaped cross-section thin plate member having a corner stiffening portion according to a sixth embodiment of the present invention for explaining the position when caulking is fixed, (b) is a caulking fixing portion It is a vertical front view which expands and shows. It is an end elevation of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the seventh embodiment of the present invention. It is an end elevation of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the eighth embodiment of the present invention. It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the ninth embodiment of the present invention. (A) An end view of a buckling stiffening structure of a box-shaped cross-section thin plate member having a corner stiffening portion according to the tenth embodiment of the present application , and (b) a corner stiffening portion according to an eleventh embodiment of the present invention. It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the twelfth embodiment of the present invention. It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the thirteenth embodiment of the present invention. It is an end elevation of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the fourteenth embodiment of the present invention. It is an end elevation of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the fifteenth embodiment of the present invention. It is an end view of the buckling stiffening structure of the box-shaped cross-section thin plate member provided with the corner stiffening portion of the sixteenth embodiment of the present invention. It is a perspective view of the framework of the conventional steel house. (A) and (B) are the end views of two examples of the conventional column member. (A), (B) (C) is an end elevation of three examples of a conventional column member, and (D) is a longitudinal front view showing an enlarged crimped portion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower frame runner 2 Column 3 Corner column 4 Vertical frame 5 Upper frame runner 6 Window opening part 7 Crib 8 Crib support 9 Arm 10 Head joint 11 Roll stopper 12 Gusset plate 13 Roof truss 13a Reinforcement bar 14 Lower chord material 15 Tut hut frame 16 Flutter 17 Head stopper 18 Grooved steel with lip 19 Assembled H-shaped steel 20 Corrugated plate 21 Web 22 Drill screw 23 Thin steel lightweight steel building 24 Closed cross-section member 25 Side 26 Corner section 27 Caulking section 28 Box-shaped cross-section thin plate member 29 Flange section 30 Plate element 31 Stiffening rib 32 Arc-shaped section 33 Box-shaped cross-section thin plate member 34 Corner stiffening section 35 Arc-shaped section 36 Opening section 37 Joint section 38 Corner steel 39 with corner stiffening section Steel section 40 with lip with corner stiffening section 40 Lip 41 Filler 42 Flange

Claims (3)

The box-shaped cross-section thin plate member having a thickness of 0.4 mm to 1.6 mm is formed by bending a thin steel plate into a box-shaped cross-sectional shape with a box-shaped cross-section thin plate member buckling stiffening structure. The box-shaped cross-section type thin plate member is formed with a corner stiffening portion at each of at least one diagonal corner in a rectangular cross-sectional shape. As a whole, the cross-sectional shape is closed to any one of 6 to 8 angles, and each corner stiffening portion is linear or arcuate on the outside of the member or arcuately on the inside of the member, and the following (1 ) a box-section-type thin plate member outer width dimension b of the box-shaped cross section type thin plate members are set so as to satisfy the equation, the respective corner stiffening portion, the direction parallel to the side to be connected thereto The width dimension D is more than twice the thickness of the thin plate member, and the outside of the two sides connected at the corner portion A corner stiffening part having a dimension of 1/3 or less of the shape width dimension b or a dimension of 1/3 or less of the outer width dimension of the shorter short side of the two sides connected at the corner part; A box shape characterized in that the width dimension D of the corner stiffening section satisfies both of the following relational expressions (2) and (3), and a value having a small upper limit is set as the width dimension D Buckling stiffening structure for cross-section thin plate members.
b> 740t / (√F) (1)
2t <D ≦ 2.0 ([b / 2] − [370 t / (√F)]) (2)
2t <D ≦ b / ((√2) +2)) (3)
However, F: Design standard strength (N / mm ² ) (value determined by Building Standard Law or yield point of steel material)
t: Thickness (mm) of the box-shaped cross-section thin plate member The box-shaped cross-section thin plate member having a thickness of 0.4 mm to 1.6 mm is formed by bending a thin steel plate into a box-shaped cross-sectional shape with a box-shaped cross-section thin plate member buckling stiffening structure. The box-shaped cross-section type thin plate member is formed with a corner stiffening portion at each corner in the diagonal direction in the rectangular cross-sectional form, and is formed as a whole. Each of the corner stiffening portions has a linear shape or an arc shape on the outer side of the member or an arc shape on the inner side of the member, and a box shape so as to satisfy the following expression (1). a box-section-type thin plate member outer width b of the cross-section-type thin plate members is set, the respective corner stiffeners, it direction parallel to the side of the width dimension D connected thereto, of the thin plate member A dimension that is more than twice the thickness of the plate and is not more than 1/3 of the outer width b of the two sides connected at the corner, Alternatively, a corner stiffening portion having a dimension that is 1/3 or less of the outer width dimension of the shorter short side of the two sides connected at the corner portion, and the width dimension D of the corner stiffening portion is as follows: A buckling stiffening structure for a box-shaped cross-section thin plate member, characterized in that a value having a small upper limit value that satisfies both the conditions of relational expressions (2) and (3) is set as the width dimension D.
b> 740t / (√F) (1)
2t <D ≦ 2.0 ([b / 2] − [370 t / (√F)]) (2)
2t <D ≦ b / ((√2) +2)) (3)
However, F: Design standard strength (N / mm ² ) (value determined by Building Standard Law or yield point of steel material)
t: Thickness (mm) of the box-shaped cross-section thin plate member The box-shaped cross-section thin plate member according to claim 1 or 2 , wherein the box-shaped cross-section thin plate member is configured by combining a plurality of thin steel plate members.

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