Structure of h-shaped steel beam, and design method of h-shaped steel beam

Abstract

To provide a structure of an H-shaped steel beam used in a building of which a stationary load or a span is large and having a rational section size and a rational section modulus without making a section size and a section modulus for the H-shaped beam excessive, and a design method of the H-shaped steel beam.SOLUTION: A structure of an H-shaped steel beam in which one or both of a distribution load and a concentrated load are applied, wherein both end parts of the H-shaped steel beam is semi-rigidly connected to members to be connected, and the H-shaped steel beam has a section modulus smaller than a section modulus calculated by performing long-term allowable stress design in a boundary condition where both the end parts of the H-shaped steel beam are rigidly connected to the members to be connected.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a structure of an H-shaped steel beam used in a building, and a design method of an H-shaped steel beam. [Background technology]

[0002] In the joints between square steel pipe columns and H-shaped steel beams in steel structural buildings, when short-term loads such as earthquake loads, or constant loads such as fixed loads and live loads are applied, stress is transmitted from the flange of the H-shaped steel beam to the side of the square steel pipe column. To prevent localized out-of-plane deformation of the square steel pipe column due to this stress, it is common to install horizontal stiffeners called diaphragms on the square steel pipe columns at the same height as the flange of the H-shaped steel beam.

[0003] The joints between square steel pipe columns and H-shaped steel beams using diaphragms are broadly classified into through diaphragm type, inner diaphragm type, and outer diaphragm type. In the through diaphragm type, as shown in Figures 7(a) and 7(b), a through diaphragm 7 is provided at the same height as the flange of the H-shaped steel beam 1 so as to penetrate the cross section of the square steel pipe column 2. In the inner diaphragm type, as shown in Figures 8(a) and 8(b), an inner diaphragm 8 is provided at the same height as the flange of the H-shaped steel beam 1 on the inside of the square steel pipe column 2 without penetrating the cross section of the square steel pipe column 2. In the outer diaphragm type, as shown in Figures 9(a) and 9(b), an outer diaphragm 9 is provided at the same height as the flange of the H-shaped steel beam 1 on the outside of the square steel pipe column 2 without penetrating the cross section of the square steel pipe column 2.

[0004] In addition, as shown in Figures 10(a) and 10(b), there is a non-diaphragm type in which no diaphragm is provided and local deformation of the skin plate of the square steel pipe column 2 is suppressed by increasing the thickness of the square steel pipe column 2 at the panel section.

[0005] Of these, in the through diaphragm type and internal diaphragm type, the effect of local deformation of the skin plate of a square steel pipe column on the deformation of the entire frame is extremely small, so it is common to treat the beam-end joint as a rigid joint in the structural design of buildings.

[0006] Furthermore, in the long-term allowable stress design of a building, it is required that the acting stress obtained by dividing the maximum bending moment acting on the beam by its section modulus must be within the long-term allowable stress of the beam, and that the ratio obtained by dividing the maximum deflection of the beam by its length must be within 1 / 250. In what follows, the former consideration of acting stress is referred to as the "stress design conditions" and the latter consideration of deflection as the "deflection design conditions."

[0007] Here, when H-shaped steel beams for buildings with large normal loads or spans are designed using long-term allowable stress design, the cross-sectional dimensions required to satisfy the design conditions for stress are often larger than the cross-sectional dimensions required to satisfy the design conditions for deflection.

[0008] This is thought to be due to the fact that beam-end connections are designed as rigid connections. In other words, if beam-end connections are designed as rigid connections for buildings with large normal loads and spans, the bending moment acting on the ends of the beams tends to increase, and as a result, the cross-sectional dimensions and section modulus of the H-shaped steel beams required to satisfy the long-term allowable stress design tend to become large.

[0009] When the cross-sectional dimensions of H-shaped steel beams become larger, the amount of welding and the number of high-strength bolts required to join components at beam end joints and beam joints increases, which can significantly reduce workability at construction sites. Also, in buildings with large spans such as logistics warehouses, the weight of the beams accounts for a large proportion of the total weight of the components of the entire building, so if the weight of the beams increases, construction costs tend to increase dramatically.

[0010] In contrast, in the case of the external diaphragm type and non-diaphragm type, by appropriately considering the local deformation of the skin plate of the square steel pipe column, the beam-end joint can be treated as a semi-rigid joint in the structural design of the building. Non-Patent Document 1 proposes a method for considering the local deformation of the skin plate of the column 2 by using a frame model 10 in which a rotational spring 3 is placed at the end of the beam 1 as shown in Figure 11 when the external diaphragm type is used for the beam-end joint. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Sui, Weining, et al., "Study on Seismic Design of Actual Frames with Exterior Diaphragm Joints," Proceedings of the Annual Conference of Steel Construction Engineers, Vol. 16, November 2008, pp. 87-94. Summary of the Invention [Problem to be solved by the invention]

[0012] In Non-Patent Document 1, a beam-end joint using an external diaphragm type is modeled as a semi-rigid joint, and a dynamic response analysis is performed to confirm the elastoplastic behavior of a frame having a semi-rigid joint. However, in Non-Patent Document 1, a rotational spring is placed directly at the end of the beam of the frame designed with a rigid beam-end joint to model the frame. Therefore, the cross-sectional dimensions of the beam in the frame model used in the dynamic response analysis are the same as those of the beam when the beam-end joint is designed with a rigid joint, and no consideration is given to making the cross-sectional dimensions of the beam reasonable.

[0013] If beam-end joints in buildings with large constant loads or spans are designed as rigid joints, the bending moment acting on the ends of the beams increases due to long-term constant loads, and the cross-sectional dimensions and section modulus of the beams required to satisfy the long-term allowable stress design tend to become large. If the cross-sectional dimensions of the beams become large, the amount of welding and the number of high-strength bolts required to join components at beam-end joints and beam joints increase, which tends to reduce workability at the construction site.

[0014] The present invention has been made to solve such problems, and aims to provide an H-shaped steel beam structure and a design method for an H-shaped steel beam used in buildings with large constant loads and spans, in which the cross-sectional dimensions and section modulus of the H-shaped steel beam are not excessively large and have reasonable cross-sectional dimensions and section modulus. [Means for solving the problem]

[0015] In order to solve the above problems, the present invention has the following features.

[0016] [1] A structure of an H-shaped steel beam on which one or both of a distributed load and a concentrated load act, wherein both ends of the H-shaped steel beam are semi-rigidly connected to the joined members, and the H-shaped steel beam has a section modulus that is smaller than the section modulus calculated by performing long-term allowable stress design under the boundary condition where both ends of the H-shaped steel beam are rigidly connected to the joined members.

[0017] Here, a semi-rigid connection is an intermediate connection between a rigid connection and a pin connection, and is a type of connection that rotates while resisting bending moments. In the structural design of buildings, a semi-rigid connection can be reflected by modeling the end of an H-shaped steel beam as being connected to the connected member via a rotational spring with rotational rigidity K (N mm).

[0018] [2] The H-shaped steel beam has a minimum yield point of 355N / mm 2 ~630N / mm 2 The structure of the H-shaped steel beam described in [1], which is an H-shaped steel in the range.

[0019] [3] A structure of an H-shaped steel beam described in [1] or [2], in which the section modulus satisfies the relationship of the following equation (1).

[0020]

number

[0021] however, Z (mm3 ): Section modulus of H-shaped steel beam l(mm): Length of H-shaped steel beam I(mm 4 ): Moment of inertia of H-shaped steel beam f t (N / mm 2 ): Long-term allowable stress of H-shaped steel beams K(N·mm): Rotational stiffness of the end of the H-shaped steel beam E(=205000N / mm 2 ):Young's modulus C (N mm): Fixed end moment generated at both ends of an H-shaped steel beam when a distributed load, a concentrated load, or both act on the H-shaped steel beam under the boundary condition that both ends of the H-shaped steel beam are rigidly connected to the connected members. [4] A design method for an H-shaped steel beam subjected to one or both of a distributed load and a concentrated load, comprising: a semi-rigid connection between both ends of the H-shaped steel beam and the joined members; and a section modulus of the H-shaped steel beam is set to be smaller than the section modulus calculated by performing long-term allowable stress design under the boundary condition that both ends of the H-shaped steel beam are rigidly joined to the joined members.

[0022] [5] The H-shaped steel beam has a minimum yield point of 355N / mm 2 ~630N / mm 2 The design method for H-shaped steel beams described in [4], in which the H-shaped steel is in the range of

[0023] [6] A design method for an H-shaped steel beam described in [4] or [5], in which the section modulus satisfies the relationship of the following equation (1).

[0024]

number

[0025] however, Z (mm 3 ): Section modulus of H-shaped steel beam l(mm): Length of H-shaped steel beam I(mm 4 ): Moment of inertia of H-shaped steel beam f t(N / mm 2 ): Long-term allowable stress of H-shaped steel beams K(N·mm): Rotational stiffness of the end of the H-shaped steel beam E(=205000N / mm 2 ):Young's modulus C (N mm): Fixed end moment generated at both ends of an H-shaped steel beam when a distributed load, a concentrated load, or both act on the H-shaped steel beam under the boundary condition that both ends of the H-shaped steel beam are rigidly connected to the connected members. Effect of the Invention

[0026] According to the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention, in the H-shaped steel beam on which one or both of a distributed load and a concentrated load act, both ends of the H-shaped steel beam are semi-rigidly connected to the column. That is, the beam end joint is treated as a semi-rigid joint in the structural design of the building, taking into account the local deformation of the skin plate of the column at the beam end joint. This allows the cross-sectional dimensions and section modulus of the H-shaped steel beam to be reduced by an amount that anticipates a reduction in the bending moment at the end of the H-shaped steel beam in the long-term allowable stress design, compared to when the beam end joint is treated as a rigid joint, resulting in a more rational structure.

[0027] Furthermore, by providing H-shaped steel beams with reasonable cross-sectional dimensions and section modulus, it is possible to improve the workability of beam-end joints and beam joints at construction sites. In particular, in buildings such as logistics warehouses where the constant load, span and planar shape of H-shaped steel beams are large, the weight of the H-shaped steel beams can be significantly reduced, resulting in a dramatic reduction in construction costs. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a diagram showing a wire model in which both ends of a beam are semi-rigidly joined to members to be joined. [Diagram 2] FIG. 2 is a diagram showing a wire model in which both ends of a beam are rigidly joined to members to be joined. [Diagram 3] 3(a) and 3(b) are diagrams showing the load distribution and bending moment distribution when a uniformly distributed load acts on the wire model shown in FIG. [Figure 4] 4(a) and 4(b) are diagrams showing the load distribution and bending moment distribution when a uniformly distributed load acts on the wire model shown in FIG. [Diagram 5] 5(a) and 5(b) are diagrams showing the load distribution and bending moment distribution when a distributed load and a concentrated load act on the model shown in FIG. [Figure 6] 6(a) and 6(b) are diagrams showing the load distribution and bending moment distribution when a distributed load and a concentrated load act on the model shown in FIG. [Figure 7] 7(a) and 7(b) are a perspective view and a plan view showing a through diaphragm type joint between a square steel pipe column and an H-shaped steel beam. [Figure 8] 8(a) and 8(b) are a perspective view and a plan view showing a joint between a square steel pipe column and an H-shaped steel beam using an internal diaphragm type. [Figure 9] 9(a) and 9(b) are a perspective view and a plan view showing a joint between a square steel pipe column and an H-shaped steel beam using an external diaphragm type. [Figure 10] 10(a) and 10(b) are a perspective view and a plan view showing a non-diaphragm type joint between a square steel pipe column and an H-shaped steel beam. [Figure 11] FIG. 11 is a diagram showing an example of a frame model in which both ends of a beam are semi-rigidly connected to columns. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the structure of an H-shaped steel beam and a design method for an H-shaped steel beam of the present invention will be described in detail with reference to the drawings.

[0030] The structure of an H-shaped steel beam and the design method of an H-shaped steel beam of this embodiment are intended for an H-shaped steel beam on which one or both of a distributed load and a concentrated load act.

[0031] As shown in Fig. 1, in the structure of the H-shaped steel beam of this embodiment, both ends of the H-shaped steel beam 1 are semi-rigidly joined to the joined members, that is, columns 2. Moreover, the H-shaped steel beam 1 has a section modulus smaller than the section modulus calculated by performing a long-term allowable stress design under the boundary condition that both ends are rigidly joined to the columns 2 as shown in Fig. 2.

[0032] In the design method of the H-shaped steel beam of this embodiment, the joints between both ends of the H-shaped steel beam 1 and the column 2 are semi-rigid joints. The section modulus of the H-shaped steel beam 1 is set to be smaller than the section modulus calculated by long-term allowable stress design under the boundary condition that both ends are rigidly joined to the column 2 as shown in FIG.

[0033] That is, the structure of the H-shaped steel beam of this embodiment is obtained by carrying out a structural design of a building including an H-shaped steel beam 1 using a frame model in which rotational springs 3 are provided at both ends of the H-shaped steel beam 1 as shown in Fig. 1, taking into account the influence of local deformation of the skin plate of the column 2 at the column-end joint. The magnitude of the rotational stiffness K of the rotational spring 3 is set by appropriately anticipating the magnitude of local deformation of the skin plate of the column 2 according to the details of the column-beam joint. Also, the design method of the H-shaped steel beam of this embodiment refers to the part of the structural design described above in which the H-shaped steel beam 1 is designed.

[0034] Either rolled H-shaped steel or welded H-shaped steel may be used for the H-shaped steel beam 1. In general buildings, H-shaped steel beams are made of ordinary steel, i.e., 400N / mm 2 Steel or 490N / mm 2 Steel is often used. The lower limit of the standard for the yield point of these steels is 235N / mm 2 , 325N / mm 2 In the structure of the H-shaped steel beam of this embodiment, these can be used as the H-shaped steel beam 1.

[0035] In addition, when a welded H-shaped steel beam 1 is used, a thick steel plate can be used. A thick steel plate with a higher strength than ordinary steel is 520N / mm 2Steel to 780N / mm 2 It is preferable to use steel types up to 355 N / mm. In other words, by using these high strength steels for the H-shaped steel beam 1, the size of the H-shaped steel beam 1 can be made smaller than when ordinary steel is used, which leads to a reduction in the weight of the H-shaped steel beam 1. In the structure of the H-shaped steel beam of this embodiment, when these high strength steels are used for the H-shaped steel beam 1, the range of the standard lower limit value of the yield point is 355 N / mm. 2 ~630N / mm 2 The range is as follows.

[0036] For the column 2, which is the member to be joined, a square steel pipe such as a cold roll-formed square steel pipe or a cold press-formed square steel pipe, or a four-sided welded box section member can be used. Also, the square steel pipe or box section member may be filled with concrete to form a concrete-filled steel pipe with increased rigidity and strength. Alternatively, instead of a square steel pipe or a four-sided welded box section member, an H-shaped steel pipe or a cross H-shaped steel pipe may be used for the column 2, which is the member to be joined.

[0037] As described above, the structure of an H-shaped steel beam and the design method of an H-shaped steel beam of this embodiment are targeted at H-shaped steel beams on which one or both of a distributed load and a concentrated load act, but the distributed load and concentrated load acting on the H-shaped steel beam 1 are set according to the individual load conditions of the building in which the H-shaped steel beam 1 is installed. Fig. 3(a) shows an example of load distribution when a uniformly distributed load acts on the wire model of the H-shaped steel beam 1 shown in Fig. 1. Fig. 5(a) shows an example of load distribution when a distributed load and a concentrated load act on the wire model of the H-shaped steel beam 1 shown in Fig. 1.

[0038] In the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of this embodiment, the section modulus Z (mm 3 ) is preferably set to satisfy the relationship of the following formula (1).

[0039]

number

[0040] however, l(mm): Length of H-shaped steel beam 1 I(mm 4 ): Moment of inertia of H-shaped steel beam 1 f t (N / mm 2 ): Long-term allowable stress of H-shaped steel beam 1 K(N mm): Rotational stiffness of the end of H-shaped steel beam 1 E(=205000N / mm 2 ):Young's modulus C (N mm): Fixed end moment generated at both ends of H-shaped steel beam 1 when a distributed load or a concentrated load or both act on H-shaped steel beam 1 under the boundary condition that both ends of H-shaped steel beam 1 are rigidly connected to the connected members. It is.

[0041] The right side of the above equation (1) is the section modulus required for the H-shaped steel beam 1, calculated by performing long-term allowable stress design under the boundary condition that both ends of the H-shaped steel beam 1 are rigidly connected to the column 2 as shown in Figure 2. The value of C is the fixed end moment generated at both ends of the H-shaped steel beam 1 when one or both of a distributed load and a concentrated load act on the H-shaped steel beam 1 under the boundary condition that both ends of the H-shaped steel beam 1 are rigidly connected to the column, and is determined according to the load conditions acting on the H-shaped steel beam 1.

[0042] For example, when a uniformly distributed load acts on the H-shaped steel beam 1 as shown in Figure 3(a), the value of the fixed end moment C in the above formula (1) is C = wl 2 / 12. In this case, the above formula (1) can be rewritten as the following formula (2).

[0043]

number

[0044] however, w(N / mm): Uniformly distributed load It is.

[0045] In addition, when a distributed load and a concentrated load act on the H-shaped steel beam 1 with the load distribution shown in Figure 5(a), the fixed end moment C in the above formula (1) is C = 17wl 2 / 384+Pl / 8. In this case, the above formula (1) can be rewritten as the following formula (3).

[0046]

number

[0047] however, w(N / mm): Maximum value of distributed load P(N): Concentrated load It is.

[0048] In general structural design, the beam end joint is treated as a rigid joint, so the section modulus of the H-shaped steel beam is determined to be equal to or greater than the section modulus shown on the right side of equations (1) to (3). In contrast, in this embodiment, the beam end joint is treated as a semi-rigid joint, so the section modulus Z of the H-shaped steel beam 1 is set to be smaller than the section modulus shown on the right side of equations (1) to (3). In other words, the H-shaped steel beam 1 has a section modulus smaller than the section modulus calculated by long-term allowable stress design under the boundary condition that both ends of the beam 1 are rigidly joined to the column 2 as shown in FIG. 2.

[0049] The left sides of the above formulas (1) to (3) are the section modulus required for the H-shaped steel beam 1, calculated by performing long-term allowable stress design under the boundary condition that both ends of the H-shaped steel beam 1 are semi-rigidly joined to the column 2 as shown in Fig. 1. In this embodiment, the section modulus Z of the H-shaped steel beam 1 is set to be smaller than the section modulus shown on the left sides of the formulas (1) to (3).

[0050] In the structure of an H-shaped steel beam and the design method of an H-shaped steel beam of this embodiment, the magnitude of local deformation of the skin plate of the column 2 is appropriately estimated according to the details of the column-beam joint, i.e., the rotational stiffness K of the rotational spring 3 at the end of the H-shaped steel beam 1 is set to an appropriate value. This allows the beam end joint to be designed as a semi-rigid joint regardless of the joint form of the column-beam joint. Therefore, there are no particular restrictions on the type of column-beam joint to which the structure of an H-shaped steel beam and the design method of an H-shaped steel beam of the present invention are applicable.

[0051] In the external diaphragm type shown in Figures 9(a) and 9(b) and the non-diaphragm type shown in Figures 10(a) and 10(b), local deformation at the beam end joint is large, and a relatively large reduction in the bending moment acting on the end of the H-shaped steel beam 1 can be expected. Therefore, by applying the H-shaped steel beam structure and H-shaped steel beam design method of this embodiment, the beam end joint can be treated as a semi-rigid joint in the structural design of a building, and the cross-sectional dimensions and section modulus of the H-shaped steel beam 1 can be reduced by the amount corresponding to the expected reduction in bending moment at the end of the H-shaped steel beam 1, resulting in a rational structure.

[0052] In addition, in the case of the through diaphragm type shown in Figures 7(a) and 7(b) and the inner diaphragm type shown in Figures 8(a) and 8(b), the beam end joint is generally treated as a rigid joint in structural design. However, the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of this embodiment can be applied to these joint types as well by appropriately considering the local deformation of the skin plate of the column 1 at the beam end joint. As a result, in the structural design of the building, the beam end joint can be treated as a semi-rigid joint, and the cross-sectional dimensions and section modulus of the H-shaped steel beam 1 can be reduced by an amount corresponding to the expected reduction in bending moment at the end of the H-shaped steel beam 1, resulting in a rational structure.

[0053] Furthermore, when an H-shaped steel column is used for the column 2, a detail using high-strength bolts to connect the column and the H-shaped steel beam can be considered. In this case, if the local deformation of the joint due to the high-strength bolt connection can be appropriately considered, the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of this embodiment can be applied to treat the beam end connection as a semi-rigid connection in the structural design of the building, and the cross-sectional dimensions and section modulus of the H-shaped steel beam 1 can be reduced by an amount corresponding to the expected reduction in bending moment at the end of the H-shaped steel beam 1, resulting in a rational structure.

[0054] In addition, when the margin of error in the cross-sectional dimensions and section modulus of the H-shaped steel beam 1 is large with respect to the design conditions for deflection, the range of the standard lower limit of the yield point for the H-shaped steel beam 1 is 355 N / mm 2 ~630N / mm 2By using high strength steel in the range, the cross-sectional dimensions and section modulus of the H-shaped steel beam 1 can be further reduced while satisfying the stress design conditions and the deflection design conditions.

[0055] Above, an embodiment of the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention has been described. The specific configuration of the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention is not limited to the above embodiment, and can be appropriately changed within the scope of the present invention. In the above embodiment, the through diaphragm type, the inner diaphragm type, the outer diaphragm type, and the non-diaphragm type shown in Figs. 7 to 10 are given as typical examples of the beam end joint. The application target of the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention is not limited to these joint types, and details with better workability may be used as necessary. In addition, in the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention, the load distribution of the distributed load and concentrated load acting on the H-shaped steel beam 1 may be asymmetric with respect to the center of the span of the H-shaped steel beam. The combination of the distributed load and concentrated load can be changed in various ways depending on the individual load conditions of the building in which the H-shaped steel beam 1 is installed.

[0056] In the above embodiment, the case where both ends of the H-shaped steel beam 1 are joined to the column 2, i.e., the H-shaped steel beam 1 is a main beam, has been described, but the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention are not limited to such an embodiment. For example, the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention can be applied to the case where both ends of the H-shaped steel beam are joined to a main beam, which is a member to be joined, i.e., the H-shaped steel beam is a sub-beam.

[0057] The joint between the minor beam and the main beam is generally treated as a pin joint, but the bending moment is large at the center of the minor beam's length, which makes it easy for the floor to sag and crack. Therefore, when both ends of the minor beam, an H-shaped steel beam, are joined to the main beam, which is the member to be joined, by applying the structure of the H-shaped steel beam and the design method of the H-shaped steel beam of the present invention, the bending moment at the center of the minor beam's length can be alleviated, and the floor can be prevented from sagging and cracking. EXAMPLES

[0058] Tables 1 and 2 show examples of the cross-sectional dimensions of an H-shaped steel beam 1 made of ordinary steel and an example of the cross-sectional dimensions of an H-shaped steel beam 1 made of high-strength steel, respectively, designed using the above formula (2) for an H-shaped steel beam 1 subjected to a uniformly distributed load as shown in Figure 3(a). Table 3 also shows examples of the cross-sectional dimensions of an H-shaped steel beam designed to satisfy the same load conditions when the joint conditions of the beam end joint are replaced with rigid joints as shown in Figure 4.

[0059] [Table 1]

[0060] [Table 2]

[0061] [Table 3]

[0062] As shown in Tables 1 to 3, the cross-sectional dimensions of an H-shaped steel beam when both ends of the beam are semi-rigidly joined are smaller than the cross-sectional dimensions of an H-shaped steel beam when both ends of the beam are rigidly joined. Specifically, it was confirmed that the weight of H-shaped steel beam 1, which uses ordinary steel, can be reduced by up to approximately 15%, and that the weight of H-shaped steel beam 1, which uses high-strength steel, can be reduced by up to approximately 22%.

[0063] Tables 4 and 5 show examples of the cross-sectional dimensions of an H-shaped steel beam 1 made of ordinary steel and an example of the cross-sectional dimensions of an H-shaped steel beam 1 made of high-strength steel, designed using the above formula (3) for an H-shaped steel beam 1 on which a distributed load and a concentrated load act with the load distribution shown in Figure 5(a). Table 6 shows examples of the cross-sectional dimensions of an H-shaped steel beam designed to satisfy the same load conditions when the joint conditions of the beam end joint are replaced with rigid joints as shown in Figure 6.

[0064] [Table 4]

[0065] [Table 5]

[0066] [Table 6]

[0067] As shown in Tables 4 to 6, the cross-sectional dimensions of the H-shaped steel beam when both ends of the H-shaped steel beam are semi-rigidly joined were smaller than the cross-sectional dimensions of the H-shaped steel beam when both ends of the H-shaped steel beam are rigidly joined. Specifically, it was confirmed that the weight of the H-shaped steel beam 1 using ordinary steel could be reduced by up to about 15%, and that the weight of the H-shaped steel beam 1 using high-strength steel could be reduced by up to about 20%. [Explanation of symbols]

[0068] 1 H-shaped steel beam (beam) 2 Part to be joined (square steel pipe column) 3 Rotational Spring 7 Through diaphragm 8 Inner diaphragm 9 Outer diaphragm 10 Skeleton Model l Length of H-beam w Distributed load P concentrated load

Claims

1. A structure of an H-shaped steel beam on which one or both of a distributed load and a concentrated load act, Both ends of the H-shaped steel beam are semi-rigidly joined to the joined members, The structure of the H-shaped steel beam has a section modulus that is smaller than the section modulus calculated by performing long-term allowable stress design under boundary conditions where both ends of the H-shaped steel beam are rigidly joined to the joined members.

2. The H-shaped steel beam has a standard lower limit of 355 N / mm ２ ~630N / mm ２ The structure of claim 1, wherein the H-shaped steel beam is in the range of .

3. The structure of an H-shaped steel beam according to claim 1 or claim 2, wherein the section modulus satisfies the relationship of the following formula (1). [0010] however, Z (mm ３ ): Section modulus of H-shaped steel beam l (mm): Length of H-shaped steel beam I (mm ４ ): Moment of inertia of H-shaped steel beam f ｔ (N / mm ２ ): Long-term allowable stress of H-shaped steel beam K (N mm): Rotational rigidity of the end of the H-shaped steel beam E(=205000N / mm ２ ): Young's modulus C (N mm): Fixed end moment generated at both ends of the H-shaped steel beam when a distributed load and / or a concentrated load acts on the H-shaped steel beam under the boundary condition that both ends of the H-shaped steel beam are rigidly connected to the connected members.

4. A method for designing an H-shaped steel beam subjected to one or both of a distributed load and a concentrated load, comprising the steps of: The joint between both ends of the H-shaped steel beam and the joined member is a semi-rigid joint, A design method for an H-shaped steel beam, in which the section modulus of the H-shaped steel beam is set to be smaller than the section modulus calculated by performing long-term allowable stress design under boundary conditions in which both ends of the H-shaped steel beam are rigidly joined to the joined members.

5. The H-shaped steel beam has a standard lower limit of 355 N / mm ２ ~630N / mm ２ The method for designing an H-shaped steel beam according to claim 4, wherein the H-shaped steel beam is in the range of

6. The design method for an H-shaped steel beam according to claim 4 or claim 5, wherein the section modulus satisfies the relationship of the following formula (1). [0025] however, Z (mm ３ ): Section modulus of H-shaped steel beam l (mm): Length of H-shaped steel beam I (mm ４ ): Moment of inertia of H-shaped steel beam f ｔ (N / mm ２ ): Long-term allowable stress of H-shaped steel beam K (N mm): Rotational rigidity of the end of the H-shaped steel beam E(=205000N / mm ２ ): Young's modulus C (N mm): Fixed end moment generated at both ends of the H-shaped steel beam when a distributed load and / or a concentrated load acts on the H-shaped steel beam under the boundary condition that both ends of the H-shaped steel beam are rigidly connected to the connected members.

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