JP2008007960A - Folded plate material for building structure - Google Patents

Abstract

An object of the present invention is to provide a folded plate material for a building structure capable of further improving the in-plane shear rigidity without reducing the out-of-plane shear rigidity (flexural rigidity).
In a folded plate material for building structure 1 in which horizontal upper and lower flanges 11 and 12 are formed via a web 13, the web 13 is inclined upward by 10 ° or more and less than 45 ° with respect to the horizontal direction. . At this time, the web 13 may be inclined upward by 30 ° or more and 40 ° or less with respect to the horizontal direction.
[Selection] Figure 1

Description

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

  In general, a folded plate used for a deck plate, a folded plate roofing material, or the like is composed of 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, Patent Documents 1 and 2 that refer to the inclination angle of the web in the folded plate are disclosed.

Patent Document 1 describes that the inclination angle of the web is about 45 °. Patent Document 2 describes that the inclination angle of the web is 55 ° to 65 °.
JP 2000-282602 A JP 60-173239 A

  In Patent Documents 1 and 2 mentioned above, the inclination angle of the web in the folded plate is set to 45 ° or more. The vertical load due to concrete, snow, or load applied when the folded plate is used for a floor or a roof. This is because the emphasis is on securing the out-of-plane bending rigidity (resistance) of the folded plate against the surface pressure load caused by wind pressure or the like applied when the folded plate is used for a roof or a wall.

  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 are also rational design methods that do not require additional structural members. 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 of the folded plate.

  However, there is a problem that in-plane shear rigidity cannot be ensured at a web inclination angle of 45 ° or more, which places importance on ensuring the out-of-plane shear rigidity of the folded plate.

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to further improve the in-plane shear rigidity without reducing the out-of-plane bending rigidity (flexural rigidity). The object is to provide a folded plate material for a building structure.

  In order to solve the above-mentioned problems, the folded sheet material for building structure according to the present invention is a folded sheet material for building structure in which horizontal upper and lower flanges are formed via the web. It is characterized by being inclined at 10 ° or more and less than 45 °.

  At this time, the web may be inclined upward by 30 ° or more and 40 ° or less with respect to the horizontal direction.

  In the present invention, in the folded plate material for building structure in which the horizontal upper and lower flanges are formed via the web, the web is inclined upward by 10 ° or more and less than 45 ° with respect to the horizontal direction. At this time, the web may be inclined upward by 30 ° or more and 40 ° or less with respect to the horizontal direction.

  When the inclination angle θ is changed, the opposite characteristics are exhibited in the shear rigidity and the flexural rigidity. The inclination angle θ is preferably in the range of 10 or more and less than 45 ° by comparing the shear rigidity and the deflection rigidity required for the folded plate, but particularly in the range of the inclination angle θ of 30 ° or more and 40 ° or less. If it is inclined, it is possible to expect an improvement in shear rigidity while suppressing a decrease in flexural rigidity.

  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. That is, the upper flange and the lower flange 12 are formed so as to be continuous via the web 13.

  This folded sheet material 1 for building structure is produced by bending a steel strip. The folded plate material 1 for building structure is applied to a roof, a floor, or a wall in a building structure.

  FIG. 2 shows a side view of a folded sheet material 1 for building structure to which the present invention is applied. The web 13 is inclined upward at an angle θ ° with respect to the horizontal direction.

  The reason for limiting the inclination angle θ of the web 13 will be described below. The following formula is based on “DIAPHRAGM DESIGN MANUAL 3rd EDITION” published by Steel Deck Institute (hereinafter referred to as “Technical Reference 1”).

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 rigidity G ′ of the folded plate 2 is given by the following equation (1).

The shear deformation Δ of the folded plate includes in-plane deformation Δ _s caused by pure shear deformation of the folded plate, distortion deformation Δ _d caused by distortion of the shape of the folded plate, and deformation Δ generated at the joint between the folded plate and the surroundings. _c . Here, FIG. 4A shows a situation where a part of the folded plate 2 is extracted and the folded plate is purely sheared, and FIG. 4B shows a situation where the folded plate is distorted. Thus, the expression (1) can be replaced with the expression (2).

  Substituting values determined by the shape of the folded plate, the physical property values, and the deformation characteristics of the surrounding joints into each term of the equation (2), the equation is expressed by the equation (3). The correspondence between the symbols representing the cross-sectional dimensions of the folded plate 2 and the cross-sectional shape is shown in FIG. In the folded plate 2 shown in FIG. 5, the length of the upper flange 11 is f, the length corresponding to a half of the lower flange 12 is e, the length of the web is w, the length of the horizontal component of the web is g, The length of the vertical component of the web (the height of the folded plate) is h, and the length corresponding to one mountain pitch including the length of the upper flange and the webs on both sides and the lower flange is d. . That is, the length d for one pitch is represented by 2e + 2g + f.

Here, paying attention to the shape of the folded plate and excluding the joint deformation coefficient C that is affected by the specifications of the joint around the folded plate, the shear rigidity G ′ of the folded plate is the in-plane deformation coefficient S _i and distortion deformation. determined by the coefficient _{D n.} Here, since the in-plane deformation coefficient S _i is significantly smaller than the distortion deformation coefficient D _n , the shear rigidity G ′ is substantially controlled by the distortion deformation coefficient D _n . In equation (2) that gives the shear stiffness G ′, the distortion deformation coefficient D _n is in the denominator, so that the greater this D _{n, the} lower the shear stiffness G ′. Conversely, shear stiffness G'higher the distortion deformation coefficient D _n is smaller the higher.

According to the technical literature 1, the distortion deformation coefficient D _n is expressed by the equation (4).

  Here, D is a value determined in accordance with the cross-sectional dimension of the folded plate and the degree of fixation to the frame material. D is expressed by equation (5).

We define the inclination angle theta of the web 13, the rigidity ratio κ relative to the case of theta = 45 °, which has been calculated based on the distortion deformation coefficient D _n. The rigidity ratio κ is given by the following equation (6) as a shear rigidity ratio obtained from a distortion deformation coefficient D _n representing the rigidity of distortion deformation shown in FIG.

  Here, in the case where three crest pitches constituted by the upper flange 11 and the web 13 and the lower flange 12 formed at both ends thereof are used as shown in FIG. The relationship of the rigidity ratio κ with respect to the inclination angle θ will be described. In FIG. 6, the correspondence between the symbol representing the cross-sectional dimension of the folded plate 2 and the cross-sectional shape is the same as in FIG.

  At this time, FIG. 7A shows the stiffness ratio κ when the inclination of the inclination angle θ is changed with d = 300 mm, h = 50 mm, and e = 25 mm. FIG. 7B shows the stiffness ratio κ when the inclination of the inclination angle θ is changed with d = 300 mm, h = 50 mm, and e = 50 mm. FIG. 7C shows the rigidity ratio κ when the inclination of the inclination angle θ is changed with d = 300 mm, h = 50 mm, and e = 75 mm.

  FIG. 8A shows the stiffness ratio κ when the inclination of the inclination angle θ is changed with d = 300 mm, h = 25 mm, and e = 25 mm. FIG. 8B shows the rigidity ratio κ when the inclination of the inclination angle θ is changed with d = 300 mm, h = 25 mm, and e = 50 mm. FIG. 8C shows the rigidity ratio κ when the inclination of the inclination angle θ is changed with d = 300 mm, h = 25 mm, and e = 75 mm.

  Here, g, f, and w, which are values other than fixed values d, h, and e, are changed as the inclination angle θ increases and decreases. From the above results, even if the dimension of e changes and the balance of the lengths of the upper flange 11 and the lower flange 12 changes, the rigidity ratio κ exceeds 1 when the inclination angle θ is less than 45 °. The shear rigidity is improved. That is, when focusing only on the in-plane shear rigidity, it is shown that the smaller the inclination angle θ, the better.

FIG. 9 shows the behavior of the in-plane deformation coefficient S _i and the distortion deformation coefficient D _n with respect to the inclination angle θ, taking as an example the case where d = 300 mm, h = 50 mm, e = 50 mm, and l = 3000 mm. Plane deformation coefficient S _i as described above, considerably compared to strain deformation coefficient D _n small shearing stiffness G'is seen to be substantially controlled to the distortion deformation coefficient D _n.

  If only the in-plane shear rigidity is focused on and the inclination angle θ is too small, as shown in FIG. Is done. Hereinafter, as in the case of the shearing rigidity, the relationship between the bending rigidity ratio η and the inclination angle θ compared to the rigidity at which the folded plate shown in FIG. .

  The flexural rigidity ratio η is given by the following equation (7).

  The sectional secondary moment I of the folded plate is expressed by the following equation (8) when a single pitch having a length d is targeted.

Here, _xn is the distance from the lower flange to the neutral axis, and is expressed by the following equation (9).

  FIG. 10A shows the deflection rigidity ratio η when the inclination of the inclination angle θ is changed with d = 300 mm, h = 50 mm, and e = 25 mm. FIG. 10B shows the deflection rigidity ratio η when the inclination of the inclination angle θ is changed with d = 300 mm, h = 50 mm, and e = 50 mm. FIG. 10C shows the deflection rigidity ratio η when the inclination of the inclination angle θ is changed with d = 300 mm, h = 50 mm, and e = 75 mm.

  FIG. 11A shows the deflection rigidity ratio η when the inclination of the inclination angle θ is changed with d = 300 mm, h = 25 mm, and e = 25 mm. FIG. 11B shows the deflection stiffness ratio η when the inclination of the inclination angle θ is changed with d = 300 mm, h = 25 mm, and e = 50 mm. FIG. 11C shows the deflection rigidity ratio η when the inclination of the inclination angle θ is changed with d = 300 mm, h = 25 mm, and e = 75 mm.

  Here, g, f, and w, which are values other than fixed values d, h, and e, are changed as the inclination angle θ increases and decreases. The lower limit of the geometrically determined inclination angle θ differs depending on the balance of the cross-sectional dimensions of d, h, and e. However, even if the angle of the inclined portion is reduced to about θ = 10 ° as shown in FIG. Thus, it is possible to ensure about 1/2 of the flexural rigidity when θ = 45 °.

  As described above, when the inclination angle θ is changed, opposite characteristics are exhibited in the shear rigidity and the flexural rigidity. The inclination angle θ is preferably in the range of 10 to less than 45 ° by comparing the shear rigidity and the deflection rigidity required for the folded plate, but particularly in the range of the inclination angle θ of 30 to 40 °. If it was made, it will become possible to expect improvement in shear rigidity while suppressing a decrease in flexural rigidity.

  The bending radius r of the plate at the ridge line where the flange and the web intersect may be an arbitrary value.

It is a block diagram of the folded-plate material for building structures to which this invention is applied. It is a side view 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 which shows the correspondence of the symbol showing the cross-sectional dimension of a folded plate, and cross-sectional shape. It is a figure which shows the side surface at the time of making three crest pitches comprised by the upper flange, the web formed in the both ends, and a lower flange into object. It is a figure which shows rigidity ratio (kappa) at the time of changing the inclination of inclination-angle (theta). It is another figure which shows rigidity ratio (kappa) at the time of changing the inclination of inclination-angle (theta). It is a diagram illustrating the behavior of the in-plane deformation coefficient for the tilt angle theta S _i and distortion deformation coefficient D _n. It is a figure which shows the bending rigidity ratio (eta) at the time of changing the inclination of inclination-angle (theta). It is another figure which shows the bending rigidity ratio (eta) at the time of changing the inclination of inclination-angle (theta). It is a figure which shows the condition where a folded plate bends and deform | transforms out-of-plane.

Explanation of symbols

1 Folded plate material for building structure 2 Folded plate 11 Upper flange 12 Lower flange 13 Web 14 Folded plate and frame material fixing point

Claims (2)

In the folded plate material for building structure in which the horizontal upper and lower flanges are formed via the web,
The folded sheet material for building structures, wherein the web is inclined upward by 10 ° or more and less than 45 ° with respect to the horizontal direction. In the folded plate material for building structure in which the horizontal upper and lower flanges are formed via the web,
The folded sheet material for a building structure, wherein the web is inclined upward by 30 ° or more and 40 ° or less with respect to a horizontal direction.