JP5176338B2 - Folded plate material for building structure - Google Patents

Description

  The present invention relates to a folded plate material for a building structure represented by a so-called deck plate, folded plate roof, siding or the like in which horizontal upper and lower flanges are formed via a web.

  In general, a folded plate used for deck plates, folded plate roofs, sidings, and the like includes a horizontal upper flange and a lower flange, and a web as an inclined portion connected between the upper flange and the lower flange.

  Conventionally, Non-Patent Document 1 discloses the contents of the shape of the corner portion of the folded plate where the flange and the web intersect. This Non-Patent Document 1 describes that the radius of curvature R at the center of the plate thickness when bending the corner is 1.5 times or more the plate thickness. However, this is a rule established to ensure the quality of the corners of the processed folded plate material (such as prevention of cracking due to plastic working). And a radius of curvature at the thickness center of about 2.0 times the thickness is taken.

  In consideration of the above-mentioned provision that the radius of curvature R at the center of the thickness shown in Non-Patent Document 1 is 1.5 times or more of the thickness, the thickness is actually about 2.0 times the thickness. A radius of curvature at the center (a radius of curvature of 2.5 times the plate thickness in the external method) is adopted. The reason for this is that when folded plates are used for floors and roofs, the surface of the folded plates, such as concrete weight, vertical load due to snow and loads, wind pressure applied when folded plates are used for roofs and walls, etc. This is because an orthogonal load is applied, and importance is attached to securing out-of-plane bending rigidity and proof stress to resist this.

  In other words, in the conventional folded plate, the radius of curvature of the corner portion is kept small, and the width of the flat portion of the upper and lower flanges is made as large as possible, thereby controlling the rigidity (resistance) for resisting out-of-plane bending deformation of the folded plate. The moment of inertia of the cross section is secured.

  An example of the shape of a folded plate represented by a conventional deck plate is shown in FIG. In the folded plate 7, a horizontal upper flange 71 and a lower flange 72 are formed via a web 73, and an intersection 74 between the upper flange 71 and the web 73 is bent with a predetermined curvature. The lower flange 72 is fixed to the frame member 75 at the fixing portion 76 by screws, welding, bolts or the like.

  The height H of the folded plate 7 is 50 mm, the width WF of the upper and lower flanges 71 and 72 is 100 mm, the plate thickness t is 1.2 mm, and the radius of curvature (plate thickness center) R at the intersecting portion 74 is Expressed by a function of plate thickness t, R = 2.0t. Here, since the plate thickness t is 1.2 mm, R = 2.4 mm (external radius of curvature: Ro = 2.5 t = 3.0 mm). When the angle θ between the flanges 71 and 72 and the web 73 is 60 °, as shown in FIG. 13B, the flanges 71 and 72 start from the bending start point bs where the bending at the intersecting portion 74 starts. The length RF up to the intersection be on the extended line between the surface and the surface of the web 73 is 1.7 mm.

  When the length between the intersections located at both ends of the flanges 71 and 72 is the width WF of the flanges 71 and 72, the ratio of RF to WF is RF / WF = 0.17. On the other hand, it can be seen that RF is suppressed to a smaller value, and the width FF of the flat portion of the flanges 71 and 72 is increased.

  On the other hand, when the building receives an earthquake force or wind pressure, a shearing force acts in the in-plane direction of the floor, roof, or wall in addition to the above-described vertical load or surface pressure load. In order to resist these shearing forces, there is a design method in which additional structural members such as braces are arranged in the in-plane direction of the floor, roof, or wall. There is also a rational design method that does not require an additional structural member such as a brace. In accordance with the latter design method, when a folded plate is used as a structural material for a floor, a roof, or a wall, it is important to ensure in-plane shear rigidity (resistance) of the folded plate.

  However, in the conventional folded plate, the main point is to ensure the out-of-plane bending rigidity of the folded plate, and the length from the bending start point on the flange surface to the intersection point on the extension line between the flange surface and the web surface. Since the cross-sectional shape is such that RF is minimized, there is a problem that in-plane shear rigidity cannot be ensured.

As another conventional technique, as shown in FIG. 14, there is a corrugated sheet 8 in which a steel sheet is formed into a waveform having a continuous curvature. The cross-sectional shape of the corrugated plate 8 can be regarded as a cross-sectional shape in which the radius of curvature is increased until the flat portions of the flanges 71 and 72 in the folded plate 7 are eliminated. However, since the corrugated plate 8 is not formed with a flat surface portion, when the plate is fixed to the frame member, only the peak 81 of the mountain and the peak 82 of the valley are in contact with the frame member 85, and a sufficient fixing degree is obtained. It cannot be secured. Further, if the corrugated plate 8 and the frame member 85 are forcibly brought into contact with each other for securing the fixing degree, the corrugated plate 8 may be deformed. Furthermore, in order to prevent the deformation of the corrugated sheet 8, a method of filling the gap between the corrugated sheet 8 and the frame member 85 with a special hardware is also conceivable. However, the number of parts and construction labor increase, leading to an increase in cost. There is a problem.
JIS G 3352 deck plate

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is a cross-sectional shape that can be sufficiently fixed to a frame material and can ensure high in-plane shear rigidity. It is providing the folded-plate material for building structures which has this.

  In order to solve the above-mentioned problem, the present inventor is a folded plate material for a building structure in which an upper flange and a lower flange having a substantially horizontal plane portion are formed through a web, and the intersection of the flange and the web. The portion RF is bent with a predetermined curvature, and the length RF from the bending start point on the flange surface to the intersection point on the extension line between the flange surface and the web surface is the length WF between the intersection points located at both ends of the flange. Invented the folded plate material for building structures adjusted in relation to

That is, in the invention according to claim 1 of the present invention, in the folded plate material for a building structure in which the upper flange and the lower flange having a substantially horizontal plane portion are formed via the web, the intersection between the flange and the web is The length RF between the bending start point on the flange surface and the intersection point on the extension line between the flange surface and the web surface is a length between the intersection points located at both ends of the flange. with it being less than 30% 20% or more of the WF, the length WF between the intersection points of vertical separation H between the planar portion and the flat portion of the lower flange of the upper flange 0.5 to 3.0 It is characterized by being double.

  In the present invention having the above-described configuration, the length RF to the intersection on the extension line between the flange surface and the web surface is set to 10% or more of the length WF between the intersections located at both ends of the flange. The in-plane shear rigidity can be improved.

Hereinafter, as a best mode for carrying out the present invention, a folded plate material for a building structure in which horizontal upper and lower flanges are joined via a web will be described in detail with reference to the drawings.
The folded plate material 1 for building structure to which the present invention is applied includes, for example, a horizontal upper flange 11 and a lower flange 12 as shown in FIG. 1 and a web 13 formed between the upper flange 11 and the lower flange 12. I have. The flanges 11 and 12 and the web 13 are formed so as to be continuous via the intersection 14.

  The folded plate material 1 for building structure is produced by bending a steel strip by roll forming or press forming. The folded plate material 1 for building structure is applied to a roof, a floor, a wall and the like in a building structure.

  Fig.2 (a) has shown sectional drawing of the folded-plate material 1 for building structures to which this invention is applied. The upper flange 11 and the lower flange 12 each have a flat surface portion 15, and the intersection portion 14 where the upper and lower flanges 11, 12 and the web 13 intersect has a predetermined curvature. Here, the height of the folded plate 1 for building structure is H, and the angle between the upper flange 11 and the web 13 and the angle between the lower flange 12 and the web 13 are θ.

FIG. 2B shows an enlarged view of the upper flange as an example. Here, the length from the bending start point bs at which the bending at the intersection 14 starts to the intersection be on the extension line between the surface of the upper flange 11 and the surface of the web 13 is RF, and the intersection points located at both ends of the upper flange 11 The length between them is WF. The width of the plane portion of the upper flange 11 is FF.
This FF corresponds to the length between the bending start points bs in the upper flange 11. In addition, this FF is a length that does not hinder fixing a frame material or a non-structure material (heat insulating material or waterproof material) (not shown) with screws, welding, bolts, etc., regardless of the shape of the folded plate material 1 for building structure. Specifically, it is desirable that this FF is composed of about 5 to 20 mm or more. Although the upper flange has been described above as an example, the same applies to the lower flange.

  The folded plate material 1 for building structure to which the present invention is applied is characterized in that the ratio of RF to WF as the flange width is optimized. The reason for limiting the ratio of RF to WF will be described below.

  FIG. 3 shows an example in which the folded plate 2 represented by the folded plate material 1 for building structure is disposed on the outer frame 3 provided inside the inner frame 4. The shear deformation amount Δ is composed of the shear deformation of the folded plate 2 and the deformation generated at the joint portion around the folded plate 2. The deformation of the folded plate 2 itself can be classified into a pure shear deformation A of the plate element shown in FIG. 4 (a) and a deformation B shown in FIG. 4 (b) in which the cross section of the folded plate is distorted. Compared to the deformation amount of the former pure shear deformation A, the deformation amount of the deformation B in which the latter cross section is distorted is remarkably large. That is, since this deformation B dominates the shear deformation of the folded plate itself, suppressing the deformation B is important for improving the in-plane shear rigidity (resistance) of the folded plate.

  About the deformation | transformation B with which a cross section is distorted, the relationship between the deformation | transformation property at the time of a cross section distorting and a cross-sectional shape can be grasped | ascertained generally by the plane frame analysis which made the cross section of a folded plate object.

  FIG. 5A shows an analysis sample P in which the curvature is eliminated by making the intersecting portion 14 square and the RF is 0 mm. In this analysis sample P, H = 100 mm, WF = 100 mm, RF = 0 mm, θ = 60 °, and t = 1 mm for each size. Further, FIG. 5B shows an analysis sample Q provided with a predetermined curvature at the intersection 14. In this analysis sample Q, H = 100 mm, WF = 100 mm, RF = 30 mm, θ = 60 °, and t = 1 mm for each size.

  As an analysis model, a cross section having a thickness of unit width (1 mm) was assumed, and a beam element of 1 mm (plate thickness) × 1 mm (unit width) was used. In the analysis, it is assumed that the center 21 of the lower flange 12 is fixed to the frame member, the points of the center 21 of the lower flange 12 located on both sides of the upper flange 11 are pin-supported, and a cross section is formed at the center 22 of the upper flange 11 The load P which tries to distort the load is applied, and the deformation δ in the load direction at the applied point is obtained.

  FIG. 6 shows the relationship of load P-deformation δ obtained from the elastic analysis for the plane frame of FIG. When compared at the same load level, the analysis sample Q with RF = 30 mm produces less deformation than the analysis sample P with RF = 0 mm, and increasing the RF can improve the rigidity against deformation with a distorted cross section. I understand.

  FIGS. 7A and 7B show the bending moment distribution obtained by the analysis. 7 (a) and 7 (b), the bending moment is large at both ends of the upper and lower flanges 11 and 12. In the analysis sample Q, as compared with the analysis sample P, by increasing the RF, the length of the beam is intensively shortened in the region where the bending moments at both ends of the flanges 11 and 12 are increased, and the deformation due to the distortion of the cross section. It can be seen that this is effectively suppressed.

  Next, a description will be given of FEM analysis performed in order to verify the effect of increasing the RF at the intersection 14 on the improvement of the shear rigidity with the three-dimensional deformation behavior that actually occurs. FIG. 8 shows an analysis model used for this FEM analysis. FIG. 8A shows the analysis model viewed from the front, and FIG. 8B shows the analysis model viewed from above. It is a shape.

  In this FEM analysis, assuming that the center 21 of the lower flange 12 is fixed to the frame member, one center 21a of the lower flange 12 is pin-supported, and the other center 21b is assumed to be a pin roller. In this FEM analysis, a load P is applied in the y direction in the figure, that is, in the depth direction in FIG. 8A, and in the upper direction in FIG. 8B, and the shear deformation δ in the load direction is obtained. . Further, the load P obtained by the analysis was divided by the deformation δ to obtain the shear rigidity P / δ.

  In this FEM analysis, as shown in FIG. 9, H = 50 mm, WF = 58 mm, θ = 60 °, and t = 1 mm are common, and RF = 0 mm for analysis sample C1, and RF for analysis sample C2. = 14.5 mm, and in the analysis sample C3, RF = 29 mm. As a result, the analysis samples C1 to C3 are expressed in shapes as shown in FIGS. 9 (a) to 9 (c), respectively. The RF / WF of the analysis sample C1 is 0, the RF / WF of the analysis sample C2 is 0.25, and the RF / WF of the analysis sample C3 is 0.5.

  FIG. 10 shows the result of this FEM analysis. In FIG. 10, the horizontal axis represents RF / WF, and the vertical axis represents the rigidity ratio. The stiffness ratio here is the stiffness ratio of the other analysis samples C2 and C3 when the stiffness P / δ of the analysis sample C1 with RF / WF = 0 is used as a reference.

  From FIG. 10, it can be seen that the stiffness ratio increases as RF / WF increases, that is, the shear stiffness improves as RF / WF increases.

  In order to confirm in more detail the effect of RF / WF on the improvement of the shear stiffness of the folded plate, the plane frame analysis model shown in FIG. 5 is used, the parameters constituting the cross-sectional shape are changed, and the analysis results are compared. It was decided. FIG. 11A shows the relationship of the rigidity ratio (vertical axis) to RF / WF (horizontal axis) when WF is 0.5H and θ is 30 °, 45 °, 60 °, and 90 °, respectively. Show. Incidentally, the rigidity ratio here is obtained on the basis of the case where RF / WF = 0 at each θ. FIG. 11B shows the relationship of the rigidity ratio (vertical axis) to RF / WF (horizontal axis) when WF is H and θ is 30 °, 45 °, 60 °, and 90 °, respectively. Yes. FIG. 11 (c) shows the relationship of the stiffness ratio (vertical axis) to RF / WF (horizontal axis) when WF is 2H and θ is 30 °, 45 °, 60 °, and 90 °, respectively. Yes. FIG. 11 (d) shows the relationship of the stiffness ratio (vertical axis) to RF / WF (horizontal axis) when WF is 3H and θ is 30 °, 45 °, 60 °, and 90 °, respectively. Yes.

  Although the stiffness ratio varies slightly depending on the shape of the cross section, it is shown that the stiffness ratio increases in the range of RF / WF ≧ 0.1. In the case of “WF = 0.5H to 3H” and “θ = 30 ° to 90 °” shown in FIGS. 11A to 11D, the average stiffness ratio at RF / WF = 0.1 is It is about 1.1, and the rigidity is improved by about 10% on average. Similarly, the average stiffness ratio at RF / WF = 0.2 is about 1.25, which is an average improvement of about 25%. That is, when RF / WF ≧ 0.2, it can be seen that a more significant rigidity improvement effect can be obtained.

  Note that the cross-sectional shape in the case of WF = H and θ = 60 ° shown in FIG. 11B substantially corresponds to the cross-section of the FEM analysis model shown in FIG. 9, but FIG. ) Of θ = 60 ° and the graph of FIG. 10 which is the result of the FEM analysis correspond well, and the examination result by the above-described plane frame analysis is the three-dimensional of the folded plate material 1 for building structures. It can be said that the typical deformation behavior is evaluated appropriately.

  The reason for limitation of the ratio of the width RF of the bent portion to the flange width WF has been described above. About the other cross-sectional shape of the folded plate material 1 for building structures, the height H = 10 to 200 mm, WF = 15 to 300 mm, θ = 30 to 90 °, the plate thickness t = 0.5 to 3.0 mm, folding The length L of the plate may be in the range of about 300 to 6000 mm, and any size suitable for the target structure may be used. In addition, increasing the ratio of the width RF of the bent portion to the flange width WF slightly reduces the out-of-plane bending rigidity of the folded plate. What is necessary is just to determine the cross-sectional shape of a board.

  Note that FIG. 12 is intended for the cross section used in the study shown in FIG. 11, with WF in the range of 0.5H to 3H, θ in the range of 30 ° to 90 °, and RF / WF = 0 for each θ as a reference for comparison. This is the ratio of the calculated out-of-plane bending stiffness (secondary moment of section), and shows the relationship between RF / WF (horizontal axis) and the out-of-plane bending stiffness ratio (vertical axis). In each case, in the range of RF / WF ≦ 0.4, the out-of-plane bending rigidity ratio is generally higher than 0.8, and the degree of reduction in out-of-plane bending rigidity can be appropriately suppressed. Therefore, when 0.1 ≦ RF / WF ≦ 0.4, and further 0.2 ≦ RF / WF ≦ 0.4, both in-plane shear rigidity and out-of-plane bending rigidity are well balanced. It can be set as a folded plate material for building structures.

  In the present invention, a cross section having the same size and shape on the upper flange 11 side and the lower flange 12 side is illustrated. However, the length of the upper and lower flanges 11 and 12 and the ratio of the width RF of the intersecting portion to the flange width WF, etc. Needless to say, the lower flange 12 may have a different shape, or may be arbitrarily modified such that the present invention is applied to only one of the upper flange and the lower flange.

It is a perspective view of the folded-plate material for building structures to which this invention is applied. It is sectional drawing of the folded-plate material for building structures to which this invention is applied. It is a figure which shows the example which arrange | positions the folded plate represented by the folded-plate material for building structures in the outer frame which provided the inner frame inside. (a) is a diagram showing a situation where the folded plate is purely sheared, and (b) is a diagram showing a situation where the folded plate is distorted and deformed. It is a figure for demonstrating a plane frame analysis model. It is a figure which shows the relationship of the load P-deformation (delta) obtained from the elastic analysis which made the plane frame object. It is a figure which shows the bending moment distribution obtained by analysis. It is a figure for demonstrating a FEM analysis model. It is a figure which shows each analysis sample in a FEM analysis model. It is a figure which shows the result of FEM analysis. It is a figure which shows the relationship of the rigidity ratio (vertical axis) with respect to RF / WF (horizontal axis) when (theta) is 30 degrees, 45 degrees, 60 degrees, and 90 degrees, respectively. It is a figure which shows the relationship of the rigidity ratio (vertical axis) of out-of-plane bending with respect to RF / WF (horizontal axis) when θ is 30 °, 45 °, 60 ° and 90 °, respectively. It is a figure which shows the shape of the folded plate represented by the conventional deck plate etc. It is a figure which shows the corrugated sheet which shape | molded the steel plate in the waveform which has the continuous curvature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Folding board material 11 for building structures Upper flange 12 Lower flange 13 Web 14 Crossing part 15 Plane part

Claims (1)

In the folded plate material for a building structure in which an upper flange and a lower flange having a substantially horizontal plane portion are formed via a web, the intersection between the flange and the web is bent with a predetermined curvature, and the flange The length RF from the bending start point on the surface to the intersection on the extended line between the flange surface and the web surface is 20% or more and 30% or less of the length WF between the intersections located at both ends of the flange. The length WF between the intersections is 0.5 to 3.0 times the vertical distance H between the plane portion of the upper flange and the plane portion of the lower flange. Folded plate material.

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