JP2010101111A - Steel plate structural member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel plate structural member, configured to have a further high compression strength by designing an effective shape or layout of a reinforcement rib. <P>SOLUTION: The steel plate structural member 1 is obtained by forming a steel plate having a fixed plate thickness t into a square pipe shape having a rectangular section, and has reinforcement ribs 15 formed on lateral side surfaces 13 and 14. The reinforcing rib 15 extends in the longitudinal direction of the side surface 13 while being obliquely folded up and down between an upper side end 13a and a lower side end 13b of the side surface 13 in a zigzag shape, and each of folded parts 16a and 16b disposed along the upper and lower side edges 13a and 13b of the side surface 13 has a semicircular shape. The reinforcement rib 15 has a planar shape determined so that, when the plate thickness of the steel plate forming the side surface 13 is t, the apexes 19a, 19b of each folded part 16a, 16b are within end areas 20a, 20b that are a strip-shaped area having a distance of from 5t to 15t from each of the upper and lower side ends 13a and 13b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a steel plate structural material formed of a thin steel plate, and in particular, by increasing the out-of-plane rigidity of a side surface portion that receives a compressive load in the in-plane direction, the compressive strength against a load orthogonal to the material axis direction is increased. The present invention relates to an improved steel plate structural material.

  2. Description of the Related Art Conventionally, steel sheet structural materials in which thin steel plates are formed into rectangular tubes having a rectangular cross section have been used from the viewpoints of weight reduction of structural materials, ease of processing and joining, and the like. However, such a structural member made of a steel plate has a problem that it is likely to buckle when a compressive load is applied in the in-plane direction of the steel plate, and the compressive strength is low.

  Increasing the thickness of the steel plate can prevent buckling and increase the compressive strength of the member. However, this increases the weight of the member and increases the material cost. In view of this, a steel plate structural material has been proposed in which reinforcing ribs are formed on a steel plate portion that receives a compressive load in the in-plane direction to improve the out-of-plane rigidity and the compressive strength. For example, Patent Document 1 discloses a groove-like engagement extending in a longitudinal direction (material axis direction) along both side ends of a steel plate forming a side surface in a square pipe member made of steel plate having a square tubular cross section. A description is given in which a joint recess is formed, and short reinforcing ribs extending in the width direction of the side surface (a direction perpendicular to the material axis) are formed at equal intervals in a portion between the two engagement recesses.

JP-A-10-266458

  The reinforcing rib provided on the conventional steel plate structural material extends in the longitudinal direction (material axis direction) of the side surface of the steel plate structural material as in Patent Document 1, or the width direction (material axis) of this side surface. The effect of improving the compressive strength by such a reinforcing rib was such that the compressive strength was improved by about 30% compared to the case where no rib was provided. Although various shapes and arrangements of the reinforcing ribs are conceivable, it cannot be said that the effective arrangement and shape of the reinforcing ribs have been sufficiently studied in the conventional steel plate structural material.

  In view of such a point, the present invention is to provide a steel plate structural material configured to have a higher compressive strength than conventional ones by an effective shape and arrangement of reinforcing ribs.

The steel sheet structural material of the present invention is
A steel plate structural material having a side face that receives a compressive load in the in-plane direction,
A reinforcing rib formed on the side surface;
The reinforcing rib extends at least partially continuously along a line that folds back in a meandering or zigzag manner between both side ends of the load acting point side and the reaction point side on the side surface,
The tops of the folded portions of the reinforcing ribs facing the side of at least one of the side ends are arranged along the side ends at intervals of a predetermined pitch or less,
Each top portion is provided in a band-shaped end region having a distance of 5 t or more and a distance of 15 t or less from the side end, where t is the thickness of the steel plate forming the side surface. It is said.

  In the present invention, as described above, the steel plate has a side surface made of a steel plate in which reinforcing ribs are formed along a meandering or zigzag line, and a distance of 5 t or more and within 15 t from at least one side end of the side surface (t is The tops of the folded-back portions of the reinforcing ribs are provided at intervals equal to or less than a predetermined pitch in the end region in the thickness of the steel plate. According to such a configuration, the out-of-plane rigidity of the side surface is increased by the reinforcing rib, and the stress on the side surface is not concentrated near the side edge on the side of the acting point or the reaction point of the compressive load. To disperse. Therefore, stress concentration can be suppressed and the occurrence of local buckling can be suppressed. Thereby, while using a thin plate-shaped steel plate, it is possible to provide a steel plate structural material having a higher compressive strength than before.

  Here, the interval between the outer edges of adjacent folded portions provided in the end region is preferably 30 t or less.

  Further, the tops of the folded portions in the present invention are arranged at intervals of a predetermined pitch or less along both side ends on the side of the load acting point and the point of reaction on the side surface, and are arranged along each side end. It is desirable that the tops be provided in the end regions of the strips that are at least 5t from the side ends and within 15t. According to this configuration, the tops of the folded portions of the reinforcing ribs are arranged at intervals equal to or less than a predetermined pitch along both side edges of the side surface, so that stress concentration is suppressed near both side edges of the side surface. Therefore, local buckling is less likely to occur, and the compressive strength is improved.

  The steel plate structural material of the present invention may have a rectangular tubular cross section, and a pair of opposing side faces in the square tubular cross section are the side faces, and the reinforcing ribs are formed on each side face. . Such a rectangular tubular structural material is suitable for use as an underbar of a building fork or joist or a wall, ceiling, roof, or the like. Therefore, it is possible to provide a structural material such as a large draw, joist, or base rail having a high compressive strength.

  Moreover, it is desirable that the surface of the reinforcing rib has a shape in which corners are not formed. In this way, stress concentration on the corner is prevented, and local buckling is less likely to occur.

  The reinforcing rib has, for example, a trapezoidal cross section in which the bottom width is narrower than the width of the opening. Further, it is desirable that each folded portion has a semicircular shape, and a portion from the center point to the vertex of the semicircular shape is provided in the end region.

  According to the steel plate structural material of the present invention, the steel plate has a steel plate side surface on which reinforcing ribs are formed along a meandering or zigzag line, and a distance of 5 t or more and 15 t or less from at least one side end of the side surface. Since the tops of the folded back portions of the reinforcing ribs are provided at intervals equal to or less than a predetermined pitch in the end region in (t is the plate thickness of the steel plate), the out-of-plane rigidity of the side surface can be increased, and The stress on the side surface can be appropriately dispersed along the reinforcing rib without concentrating the stress on the side of the point of application of the compressive load or the side of the reaction point. Therefore, stress concentration can be suppressed and the occurrence of local buckling can be suppressed. Thereby, while using a thin plate-shaped steel plate, it is possible to provide a steel plate structural material having a higher compressive strength than before.

  Hereinafter, embodiments of the steel sheet structural material of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a steel plate structural material. The steel plate structural material 1 is a steel plate having a constant thickness t formed into a rectangular tube with a rectangular cross section by a method such as roll forming, and includes a bottom surface 11, a top surface 12, and left and right side surfaces 13, 14. Yes. The steel plate structural material 1 according to the present embodiment is suitably used as a base rail such as a large draw or joist of a building, or a wall, ceiling, or roof. The load applied to the top surface 12 of the steel plate structural material 1 is the compressive load in the in-plane direction on the side surfaces 13 and 14 with the side end of the side surfaces 13 and 14 on the connection side with the top surface 12 acting as a load. Works. At this time, the side end of the side surfaces 13 and 14 on the connection side with the bottom surface 11 is a reaction point of the load.

  In the present embodiment, the steel plate structural member 1 is formed using a steel plate having a thickness of 0.8 mm so that the width W of the bottom surface 11 and the top surface 12 is 65 mm and the height H of the side surfaces 13 and 14 is 80 mm. is doing. In the center of the bottom surface 11, a caulking joint portion 11 a is provided in which the ends of the steel plates are joined together. The caulking joint portion 11 a is formed such that the bottom surface side of the steel plate structural material 1 is flat and a portion where the steel plates are overlapped and bent protrudes to the inner side of the steel plate structural material 1. In addition, a groove portion 12 a having a semicircular cross section that is recessed downward is provided in the center of the top surface 12.

  FIG. 2 is a side view of a steel plate structural material. Reinforcing ribs 15 are formed on the side surfaces 13 and 14 of the steel plate structural material 1. The reinforcing rib 15 extends on the side surface 13 in the longitudinal direction of the side surface 13 while diagonally turning back and forth between the upper side end 13a and the lower side end 13b of the side surface 13 in the zigzag manner. Is formed. The reinforcing rib 15 includes a folded portion 16a that is folded upward from the downward direction, a folded portion 16b that is folded upward from the downward direction, and another folded portion 16b that extends upward or downward from each folded portion 16a (16b). The straight portion 17 connected to (16a) is provided. In the present embodiment, the angle R formed by each linear portion 17 arranged adjacent to the longitudinal direction of the side surface 13 is 7 degrees.

  The folded portions 16a and 16b of the reinforcing rib 15 have a semicircular shape with a predetermined curvature. In this embodiment, the radius R1 of the outer edge portion is 8 mm and the radius R2 of the inner edge portion is 2 mm. The folded portions 16a and 16b are formed at regular intervals (rib pitch) along the upper and lower side edges of the side surfaces 13 and 14, and this rib pitch is set to the plate thickness t of the steel plate forming the side surfaces 13 and 14. It is decided accordingly. That is, the interval between the outer edges of the ribs is determined so that the interval L1 between the outer edges of the adjacent folded portions 16a (16b) is 30 t or less. The optimum range (L1 ≦ 30t) of the rib pitch is constant regardless of the semicircular curvature. In the present embodiment, the interval between the center points 18a and 18b of the folded portions 16a and 16b or the arrangement interval L2 between the top portions 19a and 19b is 27.28 mm, and L1 is 11.28 mm. In the case of the plate thickness t = 0.8 mm, 30t = 24 mm, which satisfies the condition of L1 ≦ 30t.

  Further, the distance between the reinforcing rib 15 and the side ends 13a and 13b is also determined according to the thickness t of the steel plate forming the side surfaces 13 and 14. That is, end regions 20a and 20b, which are band-like regions having a distance of 5t to 15t from the upper and lower side ends 13a and 13b of the side surface 13, are set, and at least one of the reinforcing ribs 15 is provided in the end regions 20a and 20b. The planar shape of the reinforcing rib 15 is determined so as to arrange the portions. Desirably, the top portions 19a and 19b of the folded portions 16a and 16b may be disposed in the end regions 20a and 20b.

  In the present embodiment, since the plate thickness t = 0.8 mm, the end regions 20a and 20b are regions of 4 mm or more and 12 mm or less from the side ends 13a and 13b, respectively. The center points 18a and 18b of the folded portions 16a and 16b having a semicircular shape are arranged on the inner boundary line of the end regions 20a and 20b (position at a distance of 15t from the side ends 13a and 13b). The top portions 19a, 19b of the folded portions 16a, 16b are arranged on the outer boundary line of the end regions 20a, 20b (positions at a distance of 5t from the side ends 13a, 13b).

  FIG. 3 is a cross-sectional view of the reinforcing rib (A-A cross-sectional view of FIG. 2). The reinforcing rib 15 is formed in a groove shape having the same depth (0.8 mm) as the plate thickness t of the steel plate, and is recessed toward the inside of the steel plate structural material 1. The cross-sectional shape of the reinforcing rib 15 is a trapezoidal cross section in which the inner width W1 of the bottom surface is 4 mm and the inner width W2 of the opening is 6 mm. Since the surfaces of the connecting portions between the reinforcing rib 15 and the side surface 13 (14) on the outer peripheral side thereof are all formed in a curved shape, the side surfaces 13 and 14 have corners on the surface including the reinforcing rib 15 portion. It has no shape. By making the shape without such corners, it is difficult for stress to concentrate on specific portions of the reinforcing rib 15 and the side surfaces 13 and 14.

  As a result of studying stress analysis and compression tests under various conditions, the applicant of the present application has provided the reinforcing rib 15 having the above-described shape, thereby preventing local buckling without increasing the thickness of the steel sheet. Generation | occurrence | production can be suppressed and it came to the idea that the compressive strength of the steel-plate structural material 1 can be improved rather than the case where the reinforcement rib of a simple shape like the past is provided. The steel plate structural material 1 is a steel plate in which the reinforcing ribs 15 are formed with a plate thickness t of 0.8 mm, but when the plate thickness is 0.5 mm, the plate thickness t is the same as above. It is desirable to set the optimum range of the rib pitch of the reinforcing rib or the end region where the tip of the reinforcing rib is to be arranged with reference to the above.

  FIG. 4 is an explanatory diagram of a test body and a loading method of a compression test, FIG. 4 (a) is a test body of a comparative example, and FIG. 4 (b) is a test body of the present embodiment. The present applicant conducted a compression test on the steel plate structural material 1 provided with the reinforcing ribs 15 having the above-described shape and the steel plate structural material 100 of the comparative example provided with the conventional reinforcing ribs under the same conditions. . The steel plate structural material 100 differs from the steel plate structural material 1 only in the reinforcing rib shape. The steel plate structural member 100 is formed between two ribs 101 and 102 having a groove shape extending in the longitudinal direction of the steel plate structural member 100 along the upper and lower side edges of each side surface, and the ribs 101 and 102. Ribs 103 extending linearly in the width direction of each side surface are provided. The ribs 103 are arranged at regular intervals in the longitudinal direction of the steel plate structural member 100 and have a semicircular cross section.

  The compression test was performed by bringing the lower end surface of the load cell 105 into contact with the upper surface of the steel plate structural members 1 and 100 placed on the loading table via the fixing jig 104 or the like. The loading speed of the compressive force was 3.0 mm / min, and the situation from the elastic range until the local buckling occurred and the ultimate situation was confirmed. As a result, in the steel plate structural material 1 of the present embodiment, the slope (elastic coefficient) of the compression load-strain curve in the elastic range is 9262 N / mm at the maximum, whereas in the steel plate structural material 100 of the comparative example, 5889 N / mm. That is, it was confirmed that the elastic modulus of the steel plate structural material 1 was increased to about 1.57 times at maximum as compared with the comparative example.

  Further, as a result of confirming the deformation state in the final state, the steel plate structural material 100 of the comparative example is a steel plate structural material in which the entire side surface on which the ribs are formed is inclined or bent like a square in the final state. While the whole 100 is deformed into a largely crushed shape, in the steel sheet structural material 1 of the present embodiment, the amount of deformation gradually decreases as the distance from the load application point increases, and the entire member is greatly crushed. It was confirmed that no deformation occurred.

(Modification of Embodiment 1)
(1) In the above embodiment, the reinforcing ribs 15 are recessed toward the inside of the steel plate structural material 1. However, the reinforcing ribs 15 may be projected to the outside of the steel plate structural material 1.

(2) In the above embodiment, the reinforcing ribs 15 are formed in a zigzag shape. However, the straight portions 17 may be formed in a gentle curve shape so that the whole is meandering. Further, the reinforcing ribs 15 may not be formed on the entire surface of the side surfaces 13 and 14, but may be formed only on a portion where deformation such as local buckling is expected to occur due to a compressive load. Further, the reinforcing rib 15 may be formed intermittently along a zigzag or meandering line instead of a single continuous rib. When forming intermittently, it is desirable not to form a corner | angular part in the edge part of each rib.

(3) In the above embodiment, all the folded portions 16a, 16b are formed in the end regions 20a, 20b on the upper and lower side ends 13a, 13b, but only one of the folded portions 16a, 16b is used. May be provided only in the end region 20a or the end region 20b.

(4) In the above embodiment, the steel sheet structural material 1 is formed in a rectangular tube with a rectangular cross section. However, the steel plate structural material has various cross sections such as a hat-shaped cross section, a groove-shaped cross section, a C-shaped cross section, and a Z-shaped cross section. It is also possible to apply. In this case, in each cross-sectional shape, a reinforcing rib similar to that of the above embodiment may be formed on the side surface that receives a compressive load in the in-plane direction.

(Other embodiments)
Next, steel plate structural members 2 to 5 provided with reinforcing ribs having shapes different from those of the above embodiment will be described. FIG. 5 is a cross-sectional view of the steel plate structural material 2. The steel plate structural material 2 is a steel plate having a constant thickness t formed in a hat-shaped cross-section by a method such as roll forming, and includes a top surface 21, left and right side surfaces 22, 23, Bottom surfaces 24 and 25 extending from the lower end toward the outer side in the member width direction of the steel plate structural member 2 are provided. In this embodiment, the steel plate structural material 2 is formed using a steel plate having a thickness of 0.5 mm so that the width W of the top surface 21 is 40 mm and the height H of the side surfaces 22 and 23 is 80 mm. .

  FIG. 6 is a side view of the steel plate structural material 2. Four corrugated reinforcing ribs 26 are formed on the side surfaces 22 and 23 of the steel plate structural material 2. The cross section of each reinforcing rib 26 is arcuate. In the present embodiment, band-shaped end regions 27 a and 27 b within a distance of 10 t are set from the upper and lower end sides of the side surfaces 22 and 23 on the basis of the plate thickness t of the steel plate, and at least the reinforcing ribs 26 closest to the top surface 21 are provided. A part is disposed in the end region 27a, and at least a part of the reinforcing rib 26 closest to the bottom surfaces 24 and 25 is disposed in the end region 27b. In this embodiment, the plate thickness t = 0.5 mm, and the top of the corrugated shape of the reinforcing rib 26 of the steel plate structural material 2 is in contact with a line 10 t from the upper and lower edges of the side surfaces 22 and 23, that is, a distance of 5 mm. ing.

  A compression loading test was performed on the steel plate structural material 2 having the above shape and the steel plate structural material of the comparative example in which the reinforcing ribs 26 were not formed. The loading speed of the compressive force was set to 3.0 mm / min, and the maximum load when local buckling occurred on the side surface on which the reinforcing rib 26 was formed was measured. As a result, the maximum load was 2264 N in the comparative example, and the maximum load was 3891 N in the steel plate structural material 2 of the present embodiment. That is, an improvement in compressive strength of 70% or more was confirmed with respect to the comparative example. Further, as a result of the same compression loading test in a comparative example in which the reinforcing rib 26 is separated from the upper and lower end sides of the side surfaces 22 and 23 to a position at a distance of 7.5 mm instead of within a distance of 5 mm, buckling deformation The maximum load to reach 3009N was only about 30% improvement in compressive strength.

  FIGS. 7A to 7D are side views of steel plate structural members 3 to 6 in which reinforcing ribs having other shapes are formed. 7 (a) and 7 (b), the steel ribs 3 and 4 are respectively provided with main ribs 31 and 41 having X-shaped sideways, and an X-shaped intersection upper region and an intersection lower region. The deformed circular secondary rib 32 or the kidney-shaped secondary rib 42 is provided. The adjacent X-shaped joints of the main ribs 31 and 41 and the upper or lower portions of the sub-ribs 32 and 42 are within a distance of 10 t from the upper and lower end sides of the side surface on which these ribs are formed (t: steel plate Thickness) end regions 33a, 33b, 43a, 43b. Moreover, the main ribs 31 and 41 and the sub-ribs 32 and 42 are raised outside the steel plate structural members 3 and 4 and do not have corners on the surface. In addition, you may make the X-shaped crossing angle in the main ribs 31 and 41 gentler than the shape of Fig.7 (a) (b). When a compression loading test was performed on these steel plate structural members 3 and 4 in the same manner as the steel plate structural member 2, the maximum load leading to buckling deformation was 3802N.

  The steel plate structural member 5 in FIG. 7 (c) is formed with reinforcing ribs 51 extending in the width direction of the side face at regular intervals, and the upper and lower ends of the reinforcing ribs 51 are semicircular and have a corner portion having a cross-sectional shape. The upper and lower ends are formed in the end regions 52a and 52b within a distance of 10t (t: plate thickness of the steel material) from the upper and lower end sides of the side surface on which these ribs are formed. is there. Moreover, the steel plate structural member 6 in FIG. 7D is formed by tilting the reinforcing rib 61 obliquely, and the upper end and the lower end of the reinforcing rib 61 are formed in the end regions 62a and 62b. Thus, also about the linear reinforcement rib extended in the width direction, compressive strength can be improved compared with the past by extending the edge part to the position which enters in edge part area | region 52a, 52b, 62a, 62b. .

It is sectional drawing of the steel-plate structural material of Embodiment 1. FIG. It is a side view of the steel plate structural material of Embodiment 1. It is sectional drawing (AA sectional drawing of FIG. 2) of a reinforcement rib. It is explanatory drawing of the test body and loading method of a compression test. It is sectional drawing of the steel plate structural material of other embodiment. It is a side view of the steel plate structural material of other embodiment. It is a side view of the steel plate structural material of other embodiment.

Explanation of symbols

1, 2, 3, 4, 5, 6 Steel plate structural material 11 Bottom surface 11a Caulking joint 12 Top surface 12a Grooves 13 and 14 Side surfaces 13a and 13b Side edges 15 Reinforcement ribs 16a and 16b Folded portions 17 Linear portions 18a and 18b Center Point 19a, 19b Top part 20a, 20b End area 21 Top surface 22, 23 Side face 24, 25 Bottom face 26 Reinforcement rib 27a, 27b End area 31, 41 Main rib 32, 42 Sub rib 33a, 33b, 43a, 43b End Regions 51, 61 Reinforcing ribs 52a, 52b, 62a, 62b End region 100 Steel plate structural members 101-103 Rib 104 Fixing jig 105 Load cell

Claims (7)

A steel plate structural material having a side face that receives a compressive load in the in-plane direction,
A reinforcing rib formed on the side surface;
The reinforcing rib extends at least partially continuously along a line that folds back in a meandering or zigzag manner between both side ends of the load acting point side and the reaction point side on the side surface,
The tops of the folded portions of the reinforcing ribs facing the side of at least one of the side ends are arranged along the side ends at intervals of a predetermined pitch or less,
Each top portion is provided in a band-shaped end region having a distance of 5 t or more and a distance of 15 t or less from the side end, where t is the thickness of the steel plate forming the side surface. Steel structure material. In the steel sheet structural material according to claim 1,
A steel plate structural material, wherein an interval between outer edges of adjacent folded portions provided in the end region is 30 t or less. In the steel plate structural material according to claim 1 or 2,
The tops of the folded portions are arranged at intervals of a predetermined pitch or less along both side ends of the load acting point side and the reaction point side on the side surface,
The steel plate structural material characterized in that each of the top portions arranged along each side end is provided in each end region of a belt-like shape having a distance of 5 t or more and within a distance of 15 t from each side end. . In the steel sheet structural material according to any one of claims 1 to 3,
Has a rectangular tubular cross section,
A pair of opposite side surfaces in the rectangular tubular cross section are the side surfaces,
A steel plate structural material, wherein the reinforcing rib is formed on each side surface. In the steel sheet structural material according to any one of claims 1 to 4,
A steel plate structural material characterized in that corners are not formed on the surface of the reinforcing rib. In the steel sheet structural material according to any one of claims 1 to 5,
The reinforcing rib has a trapezoidal cross section in which the width of the bottom is narrower than the width of the opening. In the steel sheet structural material according to any one of claims 1 to 6,
Each folded portion has a semicircular shape, and a portion from the center point to the apex of the semicircular shape is provided in the end region.

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