Method for designing dry roof of steel structure

Abstract

To provide a design method of a dry roof of a steel structure capable of efficiently selecting a member of a horizontal plane of structure.SOLUTION: In the case of equation (2), a yield strength Pyf is expressed by equation (3). Therefore, in the case of equation (2), it is possible to select a deck plate 1 and a brace 22 that can satisfy the required yield strength Pyf by using equation (3). In the case of equation (4), the yield strength Pyf is expressed by equation (5). Therefore, in the case of Equation (4), it is possible to select the deck plate 1 and the brace 22 that can satisfy the required yield strength Pyf using Equation (5). In all of Expressions (2), (3), (5), and (7), the performance of the deck plate 1 and the performance of the brace 22 are taken into consideration, Therefore, it is possible to design such that the brace 22 and the deck plate 1 are used together to bear the horizontal load, and it is possible to efficiently select the member of the horizontal plane of structure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for designing a dry roof for a steel frame structure. [Background technology]

[0002] A conventional dry roof for steel frame construction is known from Patent Document 1. This dry roof for steel frame construction has column members, beam members, column-beam joints, and a deck plate. Vertical loads are borne by the column members, and horizontal loads are borne by the deck plate placed between the beam members on the top floor. There are also other structures in which braces spanning between the beam members bear horizontal loads. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Japanese Patent Application Laid-Open No. 2012-87484 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional steel-framed dry roof design methods assume that horizontal loads are carried by either braces or deck plates. When designing to accommodate braces, the performance of the dry roof is determined by the brace diameter. Therefore, to ensure high in-plane shear capacity, the braces must be large. On the other hand, when designing to accommodate deck plates, to ensure high in-plane shear capacity, the shear plate thickness must be increased and the joints must be made stronger.

[0005] On the other hand, when braces and deck plates are installed together as a dry roof for a steel frame, it is expected that both components will bear the horizontal load together. In such cases, a design method that assumes that only one of the braces or deck plates will bear the horizontal load may result in excessive performance compared to the in-plane shear performance actually required, which can be extremely uneconomical.

[0006] The present invention has been made to solve such problems, and aims to provide a design method for a dry roof of a steel frame structure that allows for efficient selection of components for the horizontal structural components. [Means for solving the problem]

[0007] The design method for a steel-framed dry roof of the present invention is a design method for a steel-framed dry roof, wherein the dry roof has a plurality of grids, and at least one of the plurality of grids has four column members, four beam members arranged between the column members, a plurality of deck plates covering the grid, and a plurality of braces spanning the surface of the grid, and the in-plane shear stiffness Kf of one grid is given by equation (1), and in the case of equation (2), the yield strength Pyf is given by equation (3), in the case of equation (4), the yield strength Pyf is given by equation (5), and in the case of equation (6), the yield strength Pyf is given by equation (7). Kf = Kd + Kb …(1) Pyd / Kd <Pyb / Kb …(2) Pyf = Pyd + Pyd Kb / Kd …(3) Pyb / Kb <Pyd / Kd …(4) Pyf = Pyb + Pyb Kd / Kb …(5) Pyd / Kd = Pyb / Kb …(6) Pyf = Pyd + Pyb …(7) however Kd: Deck plate rigidity Kb: stiffness of the brace Pyd: Yield strength of deck plate Pyb: Yield strength of brace

[0008] In the method for designing a dry roof for a steel frame structure according to the present invention, at least one grid among the plurality of grids has a plurality of deck plates and a plurality of braces. Therefore, both the deck plate and the braces can bear the horizontal load of the grid. Here, the in-plane shear stiffness Kf of at least one grid is expressed as Equation (1). Therefore, by using Equation (1), it is possible to select a deck plate and braces that can satisfy the required stiffness Kf. Furthermore, in the case of Equation (2), the yield strength Pyf is expressed as Equation (3). Therefore, in the case of Equation (2), it is possible to select a deck plate and braces that can satisfy the required yield strength Pyf using Equation (3). Furthermore, in the case of Equation (4), the yield strength Pyf is expressed as Equation (5). Therefore, in the case of Equation (4), it is possible to select a deck plate and braces that can satisfy the required yield strength Pyf using Equation (5). Furthermore, in the case of Equation (6), the yield strength Pyf is expressed as Equation (7). Therefore, in the case of formula (6), it is possible to select deck plates and braces that can satisfy the required yield strength Pyf using formula (7). Formulas (2), (3), (5), and (7) all take into account the performance of the deck plate and the brace. This makes it possible to design a structure in which the braces and deck plate work together to bear horizontal loads, allowing for efficient selection of components for the horizontal structural members.

[0009] All of the grids among the multiple grids have four column members, four beam members arranged between the column members, multiple deck plates covering the grid, and multiple braces spanning the grid's plane, and the in-plane shear stiffness Kf of all grids can be expressed as formula (1), and in the case of formula (2), the yield strength Pyf can be expressed as formula (3), in the case of formula (4), the yield strength Pyf can be expressed as formula (5), and in the case of formula (6), the yield strength Pyf can be expressed as formula (7). In this way, even when all grids are composite structures of deck plates and braces, the use of formulas (1) to (7) allows efficient selection of members for the horizontal structural surfaces of all grids.

[0010] All deck plates within a grid may be interconnected, thereby increasing the design strength of the deck plates.

[0011] Some of the deck plates in the grid may be joined to each other, thereby improving the design strength of the deck plates.

[0012] The deck plates may be joined together by a screw structure or a joint structure using fitting and welding, which allows the deck plates to be firmly joined together. [Effects of the Invention]

[0013] According to the present invention, a design method for a dry roof of a steel frame construction can be provided, which allows for efficient selection of components for horizontal structural components. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a steel-framed dry roof according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a steel-framed dry roof with some deck plates omitted. [Figure 3] FIG. 1 is a plan view of one grid. [Figure 4]FIG. 2 is a diagram showing the joining structure of the deck plate. [Figure 5] 10 is a graph for explaining the relationship between yield strengths. [Figure 6] This is a process diagram showing an example of the steps of a design method for a dry roof of a steel frame structure. [Figure 7] FIG. 1 is a plan view showing an apparatus used in an experiment. [Figure 8] 10 is a graph showing experimental results. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[0016] FIG. 1 is a perspective view of a steel-framed dry roof 100 according to an embodiment of the present invention. FIG. 2 is a perspective view of the steel-framed dry roof 100, with some deck plates 1 omitted. As shown in FIGS. 1 and 2, the dry roof 100 is a roof constructed using steel frame materials. The dry roof 100 has a plurality of grids GD. One horizontal direction is defined as a first direction D1, and the direction perpendicular to the first direction D1 is defined as a second direction D2. In this embodiment, the dry roof 100 has a total of nine grids GD1 to GD9, three in the first direction D1 and three in the second direction D2. The dry roof 100 has grids GD1, GD2, and GD3 in a first row in the first direction D1, grids GD4, GD5, and GD6 in a second row, and grids GD7, GD8, and GD9 in a third row.

[0017] In the following description, when simply referring to a "grid GD," this refers to the grids GD1 to GD9. Each grid GD is configured as a rectangular area when viewed from above and below. The number and arrangement of the grids GD on the dry roof 100 are not particularly limited. In other words, by arbitrarily setting the number and arrangement of the grids GD, a dry roof 100 of the desired shape and size can be obtained.

[0018] 3 is a plan view of one grid GD. As shown in FIG. 3, at least one grid GD among the plurality of grids GD1 to GD9 has four column members 20, four beam members 21, a plurality of deck plates 1, and a plurality of braces 22.

[0019] The grid GD has a column member 20 at each of the four corners of its rectangular region. The column members 20 are steel pipes extending in the vertical direction. Adjacent grids GD, GD share the column member 20. For example, grid GD1 and grid GD4, which are adjacent in the first direction D1, share a pair of column members 20. Grid GD1 and grid GD2, which are adjacent in the second direction D2, share a pair of column members 20.

[0020] The grid GD has four beam members 21 arranged between the column members 20. The grid GD has the beam members 21 at positions corresponding to the four sides of a rectangular area. The grid GD has a pair of beam members 21 extending in a first direction D1 and a pair of beam members 21 extending in a second direction D2. The beam members 21 extending in the first direction D1 are suspended between the pair of column members 20 spaced apart from each other in the first direction D1. The beam members 21 extending in the second direction D2 are suspended between the pair of column members 20 spaced apart from each other in the second direction D2. The column members 20 and the beam members 21 are connected via column-beam joints, which are omitted from FIG. 3, FIG. 1 and FIG. 2.

[0021] Multiple deck plates 1 cover the grid GD. The multiple deck plates 1 are arranged to cover a rectangular area surrounded by beam members 21 on all four sides. Each deck plate 1 extends longitudinally in a first direction D1. The multiple deck plates 1 are arranged side by side in a second direction D2. The deck plates 1 are joined to the beam members 21 with joining members 24, such as screws, rivets, burn-out plug welds, fillet welds, bolts, and high-strength bolts. The joining members 24 are provided on the bottom flange 2 of the deck plate 1 (see FIG. 4(a)). The number of joining points on the bottom flange 2 is not limited. For example, the bottom flange 2 may have one joining point (single-joint specification), or the bottom flange 2 may have two joining points (two-joint specification).

[0022] All deck plates 1 in the grid GD may be interconnected (integrated specification). Here, either a partial integrated specification or a full integrated specification may be adopted as the integration specification. When a partial integrated specification is adopted, some of the deck plates 1 in the grid GD are interconnected. When a full integrated specification is adopted, all of the deck plates 1 in the grid GD are interconnected. The deck plates 1 in the grid GD may not be connected to each other and may behave individually (individual specification). In the individual specification, the deck plates 1 may be fitted together. The deck plates 1 may be joined together using a screw fastening structure 60 (see FIG. 4(c)) or a welding joint structure 50 (see FIG. 4(b)). Welding may be performed using arc spot welding, fillet welding, welding with round steel bars, or the like. The deck plates 1 may have protruding portions such as ribs or jaws on each side. The fitting portions of the deck plates 1 may be omitted. In this case, a structure in which the deck plate 1 is simply overlapped with another deck plate 1 may be adopted.

[0023] The deck plate 1 will be described in detail with reference to Figure 4(a). The deck plate 1 is formed by continuously bending a strip of steel plate in the width direction, with a horizontal lower flange 2 and a horizontal upper flange 3 bent and connected together by an inclined web 4. The deck plate 1 has arm portions 5 on both sides that are parallel to and on the same plane as the lower flange 2. The deck plate 1 has a joint structure 50 formed by fitting and welding. The joint structure 50 has fitting joints on the side edges of each arm portion 5 as fitting structures 51. One fitting joint is a female fitting joint 6 that opens downward. The other fitting joint is a male fitting joint 7 that protrudes upward, and the overall cross section has a trapezoidal rectangular waveform.

[0024] As shown in Figure 4(b), the female fitting joint 6 comprises an inner surface plate 6a rising from the arm portion 5, an upper surface plate 6b bent and connected integrally with the inner surface plate 6a, the tip of which is separated from the folding plate body and is parallel to the arm portion 5, and an inclined side surface plate 6c bent and connected integrally with the upper surface plate 6b and inclined downward to approach the arm portion 5. The inner surface plate 6a, the upper surface plate 6b, and the inclined side surface plate 6c form a dovetail groove 10 that opens downward. The inner surface plate 6a may also be provided so as to rise at an angle so as to approach the folding plate body side.

[0025] The male fitting joint 7 is equipped with an inclined side plate 7a that rises from the arm portion 5 at an angle so as to approach the folding plate main body, and an upper surface plate 7b that is bent and connected integrally with the side plate 7a, moves away from the folding plate main body, and is parallel to the arm portion 5. The upper end level of the upper surface plate 7b is generally the same as the level of the lower surface of the upper surface plate 6b of the female fitting joint 6, or is at a slightly higher level.

[0026] Deck plates 1 made of folded plates with joints are installed across beam members 21 (see Figure 3), and with one deck plate 1 installed, the dovetail groove 10 of the female mating joint 6 of the other deck plate 1 is positioned so as to cover the male mating joint 7 of one deck plate 1 from above, and the male mating joint 7 of one deck plate 1 and the female mating joint 6 of the other deck plate 1 are engaged so as to fit together, forming a joint mating portion 8.

[0027] Furthermore, joining members 12 are arranged so as to be partially or entirely housed between the inclined side panel 6c of the female fitting joint 6 of one deck plate 1 and the upper surface of the arm portion 5 of the other deck plate 1, and the joining members 12 are fixed to the arm portion 5 or inclined side panel 6c of each deck plate 1 by welding W, thereby integrating adjacent deck plates 1 in the horizontal direction via the joining members 12. Joining structure 50 has joining members 12 fixed by welding W as welded structure 52.

[0028] In the example shown in Figure 4(c), the deck plates 1 are joined together using a screw fastening structure 60. The screw fastening structure 60 is formed by fastening the adjacent deck plates 1 by driving screws 53 into the overlapping area E1 where the widthwise edges of the adjacent deck plates 1 overlap. Note that screws may also be used to fasten the deck plates 1 where they overlap using an interlocking structure 51 as shown in Figure 4(b).

[0029] As shown in Figures 1 and 2, the cross-sectional shape of the peaks and valleys of the deck plate 1 extends in a first direction D1. The peaks and valleys of the deck plate 1 are aligned in a second direction D2. In this case, the first direction D1 corresponds to the span direction of the deck plate 1, and the second direction D2 corresponds to the width direction. In the example shown in Figures 1 and 2, the span direction and width direction are the same for the deck plates 1 of all grids GD1 to GD9.

[0030] As shown in FIG. 2, the grid GD has a plurality of braces 22 that are suspended across the surface of the grid GD. In this embodiment, the grid GD has a pair of braces 22. The braces 22 are formed by bending a steel rod or steel plate into an L or C shape. One brace 22 is suspended between a pair of diagonally opposed corners of the rectangular region of the grid GD. The other brace 22 is suspended between another pair of diagonally opposed corners of the rectangular region of the grid GD. Each end of the brace 22 is connected to the beam member 21 via a bracket provided at any position on the beam member 21. The deck plate 1 is provided so as to cover the braces 22 from above.

[0031] In the dry roof 100, all of the grids GD1 to GD9 may have a deck plate 1 and a brace 22. In the following description, a structure having both a deck plate 1 and a brace 22 may be referred to as a composite structure. At least one grid GD among the grids GD1 to GD9 may have a composite structure, while the other grids GD may not have a brace 22. In a grid GD having a composite structure, the brace 22 and the deck plate 1 can be used together to bear horizontal loads. This allows for efficient selection of components for the horizontal structural components during design.

[0032] Next, we will explain the conditions that a grid GD having a composite structure must satisfy during design. The in-plane shear stiffness Kf of a grid GD having braces 22 satisfies the condition of formula (1), where Kd is the deck plate stiffness and Kb is the brace stiffness. Kf = Kd + Kb …(1)

[0033] The in-plane shear yield strength Pyf of the grid GD with a composite structure satisfies the condition of formula (3) when formula (2) is used. When formula (4) is used, it satisfies the condition of formula (5). When formula (6) is used, the yield strength Pyf satisfies the condition of formula (7). Here, "Pyd: yield strength of the deck plate" and "Pyb: yield strength of the brace" are used. Pyd / Kd <Pyb / Kb …(2) Pyf = Pyd + Pyd Kb / Kd …(3) Pyb / Kb <Pyd / Kd …(4) Pyf = Pyb + Pyb Kd / Kb …(5) Pyd / Kd = Pyb / Kb …(6) Pyf = Pyd + Pyb …(7)

[0034] The relationship between the yield strength Pyf and the above-mentioned relationship will be explained with reference to Figure 5. The horizontal axis of Figure 5 is set to the shear deformation in the in-plane shear direction of the grid GD. The vertical axis is set to the in-plane shear force of the grid GD. Graph Gd in Figure 5 is a graph showing the shear force due to the mechanism of the deck plate 1. Graph Gb is a graph showing the shear force due to the mechanism of the brace 22. Graph Gx is a graph showing the shear force due to the composite structure of the deck plate 1 and the brace 22.

[0035] The design strength of the combined mechanism of the deck plate 1 and braces 22 is adjusted to match the mechanism that reaches the design strength earlier. The design strength of the deck plate 1 mechanism is when the shear force reaches the yield strength Pyd, and is indicated by the yield point P1. The design strength of the brace 22 mechanism is when the shear force reaches the yield strength Pyb, and is indicated by the yield point P2. The shear deformation "Pyd / Kd" at the yield point P1 is smaller than the shear deformation "Pyb / Kb" at the yield point P2 (equation (2) is satisfied). In other words, the deck plate 1 mechanism reaches the design strength earlier than the brace 22 mechanism. Therefore, the design strength of the combined mechanism of the deck plate 1 and braces 22 is adjusted to match the mechanism that reaches the design strength earlier. Therefore, the shear deformation at the yield point P3 of the design strength of the composite structure is "Pyd / Kd". The shear force due to the brace 22 mechanism at this time is "Pyd·Kb / Kd". From the above, the shear force at the yield point P3 of the composite mechanism is "Pyd+Pyd·Kb / Kd", which is the sum of the shear force of the deck plate 1 mechanism when the shear deformation is "Pyd / Kd" and the shear force of the brace 22 mechanism. This is the right-hand side of equation (3). In this way, when equation (2) is true, the condition of equation (3) is met.

[0036] Furthermore, if the shear deformation "Pyd / Kd" at yield point P1 is greater than the shear deformation "Pyb / Kb" at yield point P2 (if equation (4) is satisfied), the brace 22 mechanism will reach its design strength earlier than the deck plate 1 mechanism. Therefore, the design strength of the composite mechanism is adjusted to match the brace 22 mechanism. The shear force at yield point P3 of the composite mechanism is "Pyb + Pyb Kd / Kb," which is the sum of the shear force of the brace 22 mechanism and the shear force of the deck plate 1 mechanism when the shear deformation is "Pyb / Kb." This is the right-hand side of equation (5). In this way, if equation (4) is true, the condition of equation (5) is satisfied.

[0037] Next, an example of the steps of a design method for a steel-framed dry roof 100 will be described with reference to Fig. 6. Note that Fig. 6 is merely an example of the steps, and the order and content may be changed as appropriate. As shown in Fig. 6, a structure of the dry roof 100 using column members 20 and beam members 21 is set, and among multiple grids GD, a grid GD that employs a composite structure of a deck plate 1 and braces 22 is set (step S10).

[0038] Next, for grid GD employing a composite structure, the stiffness and yield strength of the composite structure are calculated using equations (1) to (5) based on the stiffness and yield strength values ​​of the deck plate 1 and braces 22 (step S20). The stiffness and yield strength of the deck plate 1 are adjusted by changing the thickness and shape of the deck plate 1, the strength of the joints, the material strength, etc. The stiffness and yield strength of the braces 22 are adjusted by changing the cross-sectional area, material strength, etc. of the braces 22.

[0039] Next, the deck plate 1 and braces 22 to be adopted are selected based on the calculation results in step S20. Here, the required stiffness and yield strength are compared with the calculation results in step S20, and a combination of deck plate 1 and braces 22 that can meet the requirements is selected (step S30). Note that calculations may be performed for multiple combinations of deck plates 1 and braces 22 in step S20, and a combination that meets the requirements may be adopted in step S30. Alternatively, calculations may be performed for any combination of deck plates 1 and braces 22 in step S20, and if the requirements are met in step S30, that combination is adopted; if not, the process may return to step S20 and calculate a different combination.

[0040] Next, the operation and effect of the design method for the steel-framed dry roof 100 according to the embodiment of the present invention will be described.

[0041] In the design method for a steel-framed dry roof 100 according to this embodiment, at least one grid GD among the multiple grids GD has multiple deck plates 1 and multiple braces 22. Therefore, both the deck plate 1 and the braces 22 can bear the horizontal load of the grid GD. Here, the stiffness Kf of at least one grid GD in the in-plane shear direction is expressed as Equation (1). Therefore, by using Equation (1), it is possible to select the deck plate 1 and the brace 22 that can satisfy the required stiffness Kf. Furthermore, in the case of Equation (2), the yield strength Pyf is expressed as Equation (3). Therefore, in the case of Equation (2), it is possible to select the deck plate 1 and the brace 22 that can satisfy the required yield strength Pyf using Equation (3). Furthermore, in the case of Equation (4), the yield strength Pyf is expressed as Equation (5). Therefore, in the case of Equation (4), it is possible to select the deck plate 1 and the brace 22 that can satisfy the required yield strength Pyf using Equation (5). Furthermore, in the case of formula (6), the yield strength Pyf is calculated using formula (7). Therefore, in the case of formula (6), it is possible to select the deck plate 1 and brace 22 that can satisfy the required yield strength Pyf using formula (7). Formulas (2), (3), (5), and (7) all take into account the performance of the deck plate 1 and the brace 22. Therefore, it is possible to design the brace 22 and deck plate 1 to work together to bear horizontal loads, allowing for efficient selection of members for the horizontal structural components.

[0042] All of the grid GDs among the plurality of grid GDs have four column members 20, four beam members 21 arranged between the column members 20, a plurality of deck plates 1 covering the grid GD, and a plurality of braces 22 spanning the grid GD's plane. The in-plane shear stiffness Kf of all grid GDs may be expressed as formula (1), and in the case of formula (2), the yield strength Pyf may be expressed as formula (3), in the case of formula (4), the yield strength Pyf may be expressed as formula (5), and in the case of formula (6), the yield strength Pyf may be expressed as formula (7). In this way, even when all grid GDs are composite structures of deck plates 1 and braces 22, the use of formulas (1) to (7) allows efficient selection of components for the horizontal structural surfaces of all grid GDs.

[0043] All the deck plates 1 in the grid GD may be mutually joined, thereby improving the design strength of the deck plates 1.

[0044] Some of the deck plates 1 among the plurality of deck plates 1 in the grid GD may be joined to each other, thereby improving the design strength of the deck plates 1.

[0045] The deck plates 1 may be joined together by a screw fastening structure 60 or a fitting and welding joining structure 50. This allows the deck plates 1 to be firmly joined together.

[0046] Next, an experiment to confirm that the performance of the brace 22 and the deck plate 1 can be evaluated by adding them together will be described with reference to Figures 7 and 8. Figure 7 is a plan view showing the device 200 used in the experiment. Figure 8 is a graph showing the experimental results.

[0047] As shown in FIG. 7, the device 200 has a pair of support members 201 and a pair of support members 202 that simulate the four beam members 21. This allows the device 200 to simulate the rectangular area of ​​one grid GD. The opposing beam members 21 have a retaining portion 206 that holds the deck plate 1 and a retaining portion 207 that holds the brace 22. The device 200 also has a driving device 203 that applies a horizontal load to the grid GD. The device 200 applies a horizontal load to the grid GD using the driving device 203 and measures the relationship between the magnitude of the load and the controlled displacement. The upper support member 201 and the support member 208 below the driving device 203 are fixed supports. The circular areas in FIG. 7 are pin joints.

[0048] First, we will explain the structure in which braces 22 are installed on the grid GD but the deck plate 1 is not installed. Figure 8(a) is a graph showing the experimental results for a structure with only braces 22. The vertical axis of the graph represents the load magnitude, and the horizontal axis represents the controlled displacement. As shown in Figure 8(a), when the braces 22 alone are subjected to repeated horizontal loads and undergo plastic deformation, they exhibit slip-type hysteresis characteristics. This indicates that a structure with only braces 22 cannot absorb energy until the load increases and cannot stably resist large deformations. This is because plastic deformation causes permanent elongation in the braces 22, and when the load transitions from compression to tension, the braces 22 do not resist until they are fully elongated. To achieve performance equivalent to that of the composite structure described below using only braces 22, the braces 22 would need to be one size larger.

[0049] Next, we will explain a structure in which a deck plate 1 is installed on the grid GD, but no braces 22 are installed. Figure 8(b) is a graph showing the experimental results for a structure with only a deck plate 1. As shown in Figure 8(b), when a structure with only a deck plate 1 is subjected to repeated horizontal loads, cracks occur in the joints, and the load capacity decreases with each cycle, making it impossible to stably resist large deformations. To achieve the same performance as the composite structure described below using only the deck, the rigidity and strength of the joints must be more than doubled.

[0050] Next, we will explain a structure in which a deck plate 1 and braces 22 are attached to a grid GD. Figure 8(c) is a graph showing the experimental results for a composite structure of a deck plate 1 and braces 22. As shown in Figure 8(c), when a horizontal load is borne using both a brace 22 and a deck plate 1, even when the maximum strength is reached, there is no sudden decrease in strength, and no slip-type hysteretic behavior is exhibited. This means that by using a design method that combines the brace 22 and deck plate 1, it is possible to economically select both.

[0051] The present invention is not limited to the above-described embodiments.

[0052] [Form 1] A method for designing a dry roof for a steel frame structure, comprising: the dry roof having a plurality of grids; At least one grid of the plurality of grids Four pillar members; four beam members disposed between the column members; A plurality of deck plates covering the grid; a plurality of braces spanning the grid surface; A design method for a dry roof of a steel frame structure, in which the in-plane shear stiffness Kf of one grid is defined as equation (1), and when equation (2) is true, the yield strength Pyf is defined as equation (3), when equation (4) is true, the yield strength Pyf is defined as equation (5), and when equation (6) is true, the yield strength Pyf is defined as equation (7). Kf = Kd + Kb …(1) Pyd / Kd <Pyb / Kb …(2) Pyf = Pyd + Pyd Kb / Kd …(3) Pyb / Kb <Pyd / Kd …(4) Pyf = Pyb + Pyb Kd / Kb …(5) Pyd / Kd = Pyb / Kb …(6) Pyf = Pyd + Pyb …(7) however Kd: Deck plate rigidity Kb: stiffness of the brace Pyd: Yield strength of deck plate Pyb: Yield strength of brace [Form 2] All grids of the plurality of grids are Four pillar members and four beam members disposed between the column members; A plurality of deck plates covering the grid; a plurality of braces spanning the grid surface; A design method for a steel-framed dry roof according to form 1, wherein the in-plane shear stiffness Kf of all grids is expressed by equation (1), and when equation (2) is given, the yield strength Pyf is expressed by equation (3), when equation (4) is given, the yield strength Pyf is expressed by equation (5), and when equation (6) is given, the yield strength Pyf is expressed by equation (7). [Form 3] 3. The design method for a steel-framed dry roof according to claim 1, wherein all of the deck plates within the grid are interconnected. [Form 4] A design method for a steel-framed dry roof according to any one of the first to third aspects, wherein some of the deck plates in the grid are interconnected. [Form 5] A design method for a steel-framed dry roof according to any one of the first to fourth embodiments, wherein the deck plates are joined together using a screw structure or a welding structure. [Explanation of symbols]

[0053] 1...deck plate, 20...column member, 21...beam member, 22...brace, 50...joint structure, 60...screw-fastened structure, 100...dry roof.

Claims

1. A method for designing a dry roof for a steel frame structure, comprising: the dry roof having a plurality of grids; At least one grid of the plurality of grids Four pillar members; four beam members disposed between the column members; A plurality of deck plates covering the grid; a plurality of braces spanning the grid surface; A design method for a steel-framed dry roof, in which the in-plane shear stiffness Kf of one grid is expressed by equation (1), and when equation (2) is expressed by equation (3), when equation (4) is expressed by equation (5), and when equation (6) is expressed by equation (7). Kf=Kd+Kb…(1) Pyd / Kd<Pyb / Kb…(2) Pyf=Pyd+Pyd・Kb / Kd…(3) Pyb / Kb<Pyd / Kd...(4) Pyf=Pyb+Pyb・Kd / Kb…(5) Pyd / Kd=Pyb / Kb...(6) Pyf=Pyd+Pyb…(7) however Kd: Deck plate rigidity Kb: stiffness of the brace Pyd: Yield strength of deck plate Pyb: yield strength of brace

2. All grids of the plurality of grids are Four pillar members and four beam members disposed between the column members; A plurality of deck plates covering the grid; a plurality of braces spanning the grid surface; A design method for a steel-framed dry roof as described in claim 1, wherein the in-plane shear stiffness Kf of all grids is expressed by equation (1), and when equation (2) is given, the yield strength Pyf is expressed by equation (3), when equation (4) is given, the yield strength Pyf is expressed by equation (5), and when equation (6) is given, the yield strength Pyf is expressed by equation (7).

3. 2. The method for designing a dry roof for a steel frame construction according to claim 1, wherein all of the deck plates within the grid are interconnected.

4. 2. The method for designing a dry roof for a steel frame structure according to claim 1, wherein some of the deck plates in the grid are joined to each other.

5. A design method for a steel-framed dry roof as described in any one of claims 1 to 4, wherein the deck plates are joined to each other using a screw structure or a welding structure.

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