JP7605066B2 - Building structure - Google Patents

Description

The present invention relates to building structures.

Rahmen-frame building structures applied to buildings are designed to resist loads such as earthquake forces by rigidly connecting one end and the other end of a load-bearing member, such as a column, in the axial direction to a connected member. A load-bearing member that can be used in this type of building structure is disclosed in Patent Document 1.

The load support member disclosed in Patent Document 1 has a structure in which two H-shaped steel members are welded together with their inner flanges in contact with each other. A load support member with such a structure can ensure high rigidity and strength against loads such as earthquake forces, compared to a support member made of a single H-shaped steel member.

Patent No. 6382363

In building structures, multiple types of load-bearing members with different rigidities may be used. For example, the load-bearing members of a building structure may be constructed using a specific support member made of two H-shaped steel welded together as disclosed in Patent Document 1, and a standard support member with a predetermined rigidity lower than that of the specific support member. In a building structure configured in this way, the standard support member and the specific support member with different rigidities work together to resist loads such as earthquake forces. In this case, the load distributed to each support member differs depending on the rigidity of each support member, and the load distributed to the specific support member with high rigidity and borne by the specific support member is greater than that of the standard support member.

When the load is distributed to each support member, the load borne by the specific support member may become excessively large compared to the standard support member. If the load borne by the specific support member exceeds its yield strength, the specific support member will reach plastic deformation earlier than the standard support member. As a result, it will no longer be possible to effectively utilize the strengths of the specific support members and the standard support members to resist the load applied to the building structure, and there is a risk that it will not be possible to efficiently improve the earthquake resistance of the building structure.

The present invention was made in consideration of these circumstances, and its purpose is to provide a building structure equipped with multiple types of load-bearing members with different rigidities, which can improve earthquake resistance.

As a result of intensive research into solving the above problems, the inventors focused on the fact that a large bending moment acts on both axial ends of a load support member when a load is applied to a building structure, and discovered that by adjusting the welding positions of the two H-shaped steels that make up the specific support member, it is possible to reduce the rigidity of the specific support member while ensuring the strength of the necessary parts of the specific support member, leading to the completion of the present invention. In other words, the present invention relates to the following inventions.

A building structure according to one aspect of the present invention includes a reference support member having a predetermined rigidity and supporting a load, a specific support member having a rigidity higher than that of the reference support member and supporting a load, a first joined member to which one axial end of the reference support member and one axial end of the specific support member are rigidly joined, and a second joined member to which the other axial end of the reference support member and the other axial end of the specific support member are rigidly joined. The specific support member includes a first H-shaped steel having a pair of first flanges and a first web connecting the first flanges to each other, and a second H-shaped steel having a pair of second flanges and a second web connecting the second flanges to each other. At this time, one of the pair of first flanges and one of the pair of second flanges are welded to each other by a welded portion with their outer surfaces in contact with each other, and the welded portion is formed only on both sides of the specified region including the axial center points of the first H-shaped steel and the second H-shaped steel so that one of the pair of first flanges and one of the pair of second flanges are not joined in the specified region.

According to this building structure, when a load such as an earthquake force is applied to the building structure, the standard support member and the specific support member, which have different rigidity, cooperate to resist the load. In this case, when the load applied to the building structure is distributed to each of the standard support member and the specific support member, the load is distributed to the specific support member with higher rigidity, and the load borne by the specific support member becomes larger than that of the standard support member.

Here, when a load is applied to the building structure, the first and second H-shaped steels constituting the specific support member are subjected to the largest bending moment at one and the other axial ends rigidly joined to the first and second joined members, respectively, and the bending moment decreases as the end approaches the axial center point. With this in mind, in the specific support member, the first flange of the first H-shaped steel and the second flange of the second H-shaped steel are welded to each other by forming welds only on both sides of a specific region including the axial center point, so that they are not joined in the specific region. By forming welds in both the axial end and other end regions on both sides of the specific region including the axial center point where a large bending moment acts, the specific support member can ensure the strength required to resist the load.

Moreover, in the specific support member, the predetermined region including the center point in the axial direction where the bending moment is small becomes a non-welded region where no weld is formed. As a result, it is possible to prevent the rate of increase in rigidity from becoming excessively larger than the strength, with respect to the rate of increase in rigidity and strength in response to the formation of welds on both sides of the predetermined region in the specific support member. That is, in the specific support member, the rate of decrease in rigidity becomes larger than the strength in response to the non-welded region. Therefore, it is possible to reduce the rigidity of the specific support member while ensuring the strength on both sides of the non-welded region in the specific support member. As a result, when the load applied to the building structure is distributed to each support member according to the magnitude of the respective rigidities of the standard support member and the specific support member, it is possible to prevent the load borne by the specific support member from becoming excessively large relative to the standard support member. Therefore, the load is distributed according to the magnitude of the strength of each support member, and it is possible to prevent the specific support member from becoming plastically deformed earlier than the standard support member, and it is possible to effectively utilize the respective strengths of the specific support member and the standard support member to resist the load, thereby improving the earthquake resistance of the building structure.

In the above building structure, the welded portion includes a first welded portion formed including one axial end of the first H-shaped steel and the second H-shaped steel, and a second welded portion formed including the other axial end of the first H-shaped steel and the second H-shaped steel.

In this embodiment, in the first and second H-shaped steels that constitute the specific support member, the first weld is formed including one end in the axial direction where the largest bending moment acts, and the second weld is formed including the other end in the axial direction, so that the strength required for the specific support member to resist the load can be more reliably ensured.

In the above building structure, the welds are formed continuously over the entire areas on both sides of the specified area.

In this embodiment, in the first and second H-shaped steels that constitute the specific support member, continuous welds are formed throughout the entire regions on one and the other axial ends, which are on both sides of a specific region including the axial center point where a large bending moment acts, so that the strength required for the specific support member to resist loads can be more reliably ensured.

In the above building structure, the welds are formed axially symmetrically on both sides of the specified area.

In this embodiment, the specific support member can support the load evenly at each of the axial ends.

In the above building structure, the axial length of the weld is set so that the stiffness ratio indicating the ratio of the stiffness of the specific support member to the stiffness of the reference support member is approximately equal to the strength ratio indicating the ratio of the strength of the specific support member to the strength of the reference support member.

In this aspect, the length of the weld is set so that the stiffness ratio and the yield strength ratio of the reference support member and the specific support member are approximately equal. This makes it possible to more reliably prevent the rate of increase in stiffness and yield strength of the specific support member from becoming excessively greater than the yield strength relative to the reference support member. Therefore, when the load applied to the building structure is distributed to each support member according to the magnitude of the stiffness of each of the reference support member and the specific support member, it is possible to more reliably prevent the load borne by the specific support member from becoming excessively greater than that of the reference support member.

In the above-mentioned building structure, the first web has through holes formed on at least both sides of the specified area, penetrating the first web in its thickness direction, and the welded portion is formed in an area that covers at least half of the through holes when viewed from a direction perpendicular to the axial direction.

In this embodiment, a through hole is formed in the first web of the first H-shaped steel that constitutes the specific support member. A worker can use the through hole when performing work such as placing a wall panel on the specific support member. In addition, when a load is applied to the building structure, there is a risk that plastic deformation may easily occur around the through hole. Therefore, the weld is formed in an area that covers at least half of the through hole when viewed from a direction perpendicular to the axial direction. This makes it possible to suppress plastic deformation from occurring around the through hole.

As described above, the present invention can provide a building structure that has multiple types of load-bearing members with different rigidities and that can improve earthquake resistance.

1 is a perspective view showing a building structure according to an embodiment of the present invention; This is a horizontal plan view of the building structure. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 3 is a cross-sectional view taken along line IV-IV in FIG. 1 is a graph showing a load-displacement curve of a support member when a horizontal load is applied to a building structure. 1 is a plan view showing the configuration of a specific support member provided in a building structure. FIG. FIG. 13 is a plan view showing a first modified example of a welded portion in a specific support member. FIG. 13 is a plan view showing a second modified example of a welded portion in a specific support member. FIG. 13 is a plan view showing a third modified example of a welded portion in a specific support member.

The following describes a building structure according to an embodiment of the present invention with reference to the drawings.

As shown in Figures 1 and 2, the building structure 1 includes a first joined member 2A, a second joined member 2B, a reference support member 3, and a specific support member 4. In the building structure 1, the reference support member 3 and the specific support member 4 are applied to columns, beams, etc. for supporting a load. Below, a case where the reference support member 3 and the specific support member 4 are applied to columns of the building structure 1 will be described. In this case, the first joined member 2A and the second joined member 2B are applied to beams of the building structure 1.

The first member 2A is a beam that extends horizontally. The second member 2B is a beam that extends horizontally vertically below the first member 2A. The second member 2B may be a building foundation. The first member 2A and the second member 2B support the reference support member 3 and the specific support member 4. The first member 2A and the second member 2B are made of, for example, H-shaped steel. In this case, the first member 2A and the second member 2B each have a pair of joining flanges 211 and a joining web 212 that connects the two joining flanges 211 together. The first member 2A and the second member 2B are arranged so that the pair of joining flanges 211 extend horizontally with the pair of joining flanges 211 aligned vertically.

The reference support member 3 and the specific support member 4 are applied to columns rigidly joined to the first and second joined members 2A and 2B so that their axial direction is parallel to the vertical direction, and are column materials that support loads. The reference support member 3 and the specific support member 4 are supported by the first and second joined members 2A and 2B at a predetermined interval in the horizontal direction. In the building structure 1, wall panels and the like are placed relative to the reference support member 3 and the specific support member 4. The area of the cross section perpendicular to the axial direction of the reference support member 3 is set to a predetermined reference cross-sectional area. On the other hand, the area of the cross section perpendicular to the axial direction of the specific support member 4 is set to a specific cross-sectional area larger than the reference cross-sectional area.

The reference support member 3 is composed of a reference H-shaped steel 31, which is a single H-shaped steel. The reference H-shaped steel 31 is a steel material extending along the axial direction, and has a pair of flanges 311 and a web 312 that connects the two flanges 311 to each other. The web 312 of the reference H-shaped steel 31 has multiple through holes 312A that penetrate the web 312 in its thickness direction. The multiple through holes 312A have a shape that allows a person (worker) to insert their hand through them, and are formed in the web 312 at a predetermined interval in the axial direction. The worker can use the through holes 312A when performing work such as placing a wall panel on the reference support member 3.

The reference H-shaped steel 31 constituting the reference support member 3 has one axial end 3A (upper end) rigidly joined to the first joined member 2A and the other axial end 3B (lower end) rigidly joined to the second joined member 2B. In this embodiment, the reference H-shaped steel 31 has one end 3A rigidly joined to the joining flange 211 of the first joined member 2A via the one-end base plate 32, and the other end 3B rigidly joined to the joining flange 211 of the second joined member 2B via the other-end base plate 33.

Specifically, one end 3A of the standard H-shaped steel 31 is welded (fillet welded) in contact with the one-end base plate 32. As a result, a welded portion 32A is formed at the boundary between the one end 3A of the standard H-shaped steel 31 and the one-end base plate 32. The one-end base plate 32 is then fixed to the joining flange 211 of the first joined member 2A by the bolt 34. As a result, the one end 3A of the standard H-shaped steel 31 is rigidly joined to the first joined member 2A. Meanwhile, the other end 3B of the standard H-shaped steel 31 is welded (fillet welded) in contact with the other-end base plate 33. As a result, a welded portion 33A is formed at the boundary between the other end 3B of the standard H-shaped steel 31 and the other-end base plate 33. The other-end base plate 33 is then fixed to the joining flange 211 of the second joined member 2B by the bolt 34. This causes the other end 3B of the reference H-shaped steel 31 to be rigidly joined to the second joined member 2B.

The specific support member 4 comprises a first H-shaped steel 41 and a second H-shaped steel 42 having the same shape as the standard H-shaped steel 31. The first H-shaped steel 41 is a steel material extending along the axial direction, and has a pair of first flanges 411A, 411B and a first web 412 connecting the first flanges 411A, 411B to each other. The second H-shaped steel 42 is a steel material extending along the axial direction, and has a pair of second flanges 421A, 421B and a second web 422 connecting the second flanges 421A, 421B to each other.

The first H-shaped steel 41 and the second H-shaped steel 42 are arranged such that the first web 412 and the second web 422 are aligned on the same vertical plane, and the first inner flange 411A of the pair of first flanges 411A, 411B and the second inner flange 421A of the pair of second flanges 421A, 421B are adjacent to each other. In this state, the other first outer flange 411B of the pair of first flanges 411A, 411B and the other second outer flange 421B of the pair of second flanges 421A, 421B constitute the outer surface of the specific support member 4. In the first H-shaped steel 41 and the second H-shaped steel 42, the first inner flange 411A and the second inner flange 421A adjacent to each other are welded (fillet welded) to each other by the first welded portion 5A and the second welded portion 5B with their outer surfaces in contact with each other. Details of the welding points between the first inner flange 411A and the second inner flange 421A will be described later.

The first web 412 of the first H-shaped steel 41 has a plurality of first through holes 412A that penetrate the first web 412 in its thickness direction. The plurality of first through holes 412A have a shape that allows a person (worker) to insert their hand, and are formed at a predetermined interval in the axial direction in the first web 412. Similarly, the second web 422 of the second H-shaped steel 42 has a plurality of second through holes 422A that penetrate the second web 422 in its thickness direction. The plurality of second through holes 422A have a shape that allows a person (worker) to insert their hand, and are formed at a predetermined interval in the axial direction in the second web 422. The worker can use the first through holes 412A and the second through holes 422A when performing work such as placing a wall panel on the specific support member 4.

The first through hole 412A and the second through hole 422A also have the function of absorbing the vibration energy transmitted to the specific support member 4 when a horizontal load P, such as an earthquake force, is applied to the building structure 1, thereby damping the shaking of the building structure 1.

The first H-shaped steel 41 and the second H-shaped steel 42 constituting the specific support member 4 have one axial end 4A (upper end) rigidly joined to the first joined member 2A and the other axial end 4B (lower end) rigidly joined to the second joined member 2B. In this embodiment, the first H-shaped steel 41 and the second H-shaped steel 42 have one end 4A rigidly joined to the joining flange 211 of the first joined member 2A via the first base plate 61 and the other end 4B rigidly joined to the joining flange 211 of the second joined member 2B via the second base plate 62.

Specifically, one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42 is welded (fillet welded) in contact with the first base plate 61. As a result, a one-end welded portion 61E is formed at the boundary between the one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42 and the first base plate 61. The first base plate 61 is then fixed to the joining flange 211 of the first joined member 2A by the bolt 63. As a result, the one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42 is rigidly joined to the first joined member 2A. Meanwhile, the other end 4B of the first H-shaped steel 41 and the second H-shaped steel 42 is welded (fillet welded) in contact with the second base plate 62. As a result, the other end welded portion 62E is formed at the boundary between the other end 4B of the first H-shaped steel 41 and the second H-shaped steel 42 and the second base plate 62. The second base plate 62 is then fixed to the joining flange 211 of the second joined member 2B by the bolts 63. This causes the other ends 4B of the first H-shaped steel 41 and the second H-shaped steel 42 to be rigidly joined to the second joined member 2B.

As shown in FIG. 3, the first base plate 61 has a first central receiving portion 61A, a pair of first outer receiving portions 61B, and a first connecting portion 61C that connects the first central receiving portion 61A and the pair of first outer receiving portions 61B. The first central receiving portion 61A receives one end of the first inner flange 411A and one end of the second inner flange 421A of the one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42. The pair of first outer receiving portions 61B receive one end of the first outer flange 411B and one end of the second outer flange 421B of the one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42. The first connecting portion 61C receives one end of the first web 412 and one end of the second web 422 of the one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42. The first central receiving portion 61A and the pair of first outer receiving portions 61B have bolt holes 61D for passing bolts 63 that secure the first base plate 61 to the joining flange 211 of the first joined member 2A.

As shown in FIG. 4, the second base plate 62 has a second central receiving portion 62A, a pair of second outer receiving portions 62B, and a second connecting portion 62C that connects the second central receiving portion 62A and the pair of second outer receiving portions 62B. The second central receiving portion 62A receives the other ends of the first inner flange 411A and the second inner flange 421A of the other ends 4B of the first H-shaped steel 41 and the second H-shaped steel 42. The pair of second outer receiving portions 62B receive the other ends of the first outer flange 411B and the second outer flange 421B of the other ends 4B of the first H-shaped steel 41 and the second H-shaped steel 42. The second connecting portion 62C receives the other ends of the first web 412 and the second web 422 of the other ends 4B of the first H-shaped steel 41 and the second H-shaped steel 42. The second central receiving portion 62A and the pair of second outer receiving portions 62B have bolt holes 62D for passing bolts 63 that secure the second base plate 62 to the joining flange 211 of the second joined member 2B.

In addition, in the first H-shaped steel 41 and the second H-shaped steel 42 constituting the specific support member 4, the setting of the dimension (width dimension) in the width direction (direction perpendicular to the first web 412 and the second web 422) of each of the first inner flange 411A, the first outer flange 411B, the second inner flange 421A, and the second outer flange 421B is not particularly limited. In the first example, the width dimensions of each of the first inner flange 411A, the first outer flange 411B, the second inner flange 421A, and the second outer flange 421B are all set to the same. In the second example, the width dimensions of each of the first inner flange 411A, the first outer flange 411B, and the second outer flange 421B are set to the same first width dimension, and the width dimension of the second inner flange 421A is set to a second width dimension smaller than the first width dimension. In the third example, the width dimensions of the first outer flange 411B and the second outer flange 421B are set to the same third width dimension, and the width dimensions of the first inner flange 411A and the second inner flange 421A are set to the same fourth width dimension that is smaller than the third width dimension.

As described above, in the first H-shaped steel 41 and the second H-shaped steel 42 constituting the specific support member 4, the adjacent first inner flange 411A and the second inner flange 421A are welded to each other by the welds 5A, 5B with their outer surfaces in contact with each other. Specifically, as shown in FIG. 2, the first inner flange 411A and the second inner flange 421A are not joined in the non-welded region 4C1, which is a predetermined region including the axial center point 4C of the first H-shaped steel 41 and the second H-shaped steel 42, so that the welds 5A, 5B are formed only on both sides of the non-welded region 4C1. That is, a first weld 5A is formed in a first welded area 4A1 on one end 4A side of a non-welded area 4C1 that includes the axial center point 4C of the first H-shaped steel 41 and the second H-shaped steel 42 in the first inner flange 411A and the second inner flange 421A, and a second weld 5B is formed in a second welded area 4B1 on the other end 4B side of the non-welded area 4C1.

Next, the rigidity and strength of the standard support member 3 and the specific support member 4 will be described with reference to the load-displacement curve graph shown in FIG. 5. The graph in FIG. 5 shows the load-displacement curve E1 of the specific support member 4, the load-displacement curve E2 of the standard support member 3, and the load-displacement curve E3 of the conventional support member. The conventional support member is a conventional support member in which a pair of adjacent inner flanges of two H-shaped steels are welded together over the entire axial length. The conventional support member is configured in the same way as the specific support member 4, except that the welded points are different from those of the specific support member 4, and the cross-sectional area is larger than that of the standard support member 3.

In this embodiment, when one axial end and the other axial end of the reference support member 3 and the specific support member 4 are fixed by rigid joining to the first joined member 2A and the second joined member 2B, the initial rigidity is used as the rigidity of each support member, and the yield strength or maximum strength is used as the strength of each support member. The initial rigidity is the horizontal rigidity represented by the horizontal load required to cause a unit horizontal displacement. The yield strength is represented by the horizontal load indicating the yield point at which the deformation of the support member changes from elastic deformation to plastic deformation. The maximum strength is represented by the maximum value of the horizontal load on the load-displacement curve.

Hereinafter, for the initial stiffness A1, yield strength B1, and maximum strength C1 of the specific support member 4 shown in the load-displacement curve E1, the initial stiffness A1 will be referred to as "stiffness A1", and the yield strength B1 and maximum strength C1 will be referred to as "strengths B1, C1". Similarly, for the initial stiffness A2, yield strength B2, and maximum strength C2 of the reference support member 3 shown in the load-displacement curve E2, the initial stiffness A2 will be referred to as "stiffness A2", and the yield strength B2 and maximum strength C2 will be referred to as "strengths B2, C2". Also, for the initial stiffness A3, yield strength B3, and maximum strength C3 of the conventional support member shown in the load-displacement curve E3, the initial stiffness A3 will be referred to as "stiffness A3", and the yield strength B3 and maximum strength C3 will be referred to as "strengths B3, C3".

As the cross-sectional area of the specific support member 4 increases relative to the reference support member 3, the stiffness A1 and strengths B1 and C1 of the specific support member 4 increase and become greater than the stiffness A2 and strengths B2 and C2 of the reference support member 3. Also, as the cross-sectional area of the conventional support member increases relative to the reference support member 3, the stiffness A3 and strengths B3 and C3 of the conventional support member increase and become greater than the stiffness A2 and strengths B2 and C2 of the reference support member 3.

Comparing the specific support member 4 with the conventional support member, the stiffness A1 of the specific support member 4 is smaller than the stiffness A3 of the conventional support member, and the strengths B1, C1 of the specific support member 4 are approximately the same as the strengths B3, C3 of the conventional support member. In other words, when focusing on the rate of increase in stiffness and strength in response to an increase in cross-sectional area relative to the standard support member 3, the rate of increase in the strengths B1, C1 of the specific support member 4 relative to the strengths B2, C2 of the standard support member 3 is approximately the same as the rate of increase in the strengths B3, C3 of the conventional support member. On the other hand, the rate of increase in the stiffness A1 of the specific support member 4 relative to the stiffness A2 of the standard support member 3 is smaller than the rate of increase in the stiffness A3 of the conventional support member.

As shown in FIG. 2, when a horizontal load P such as an earthquake force is applied to the building structure 1, the reference support member 3 and the specific support member 4, which have different rigidity according to the difference in the cross-sectional area, cooperate to resist the horizontal load P. The horizontal load P applied to the building structure 1 is distributed to each of the reference support member 3 and the specific support member 4 according to the rigidity of each of them. When the horizontal load P applied to the building structure 1 is distributed to each of the reference support member 3 and the specific support member 4, the horizontal load P1 distributed to the specific support member 4 with high rigidity and borne by the specific support member 4 is greater than the horizontal load P2 borne by the reference support member 3.

Here, when a horizontal load P is applied to the building structure 1, the first H-shaped steel 41 and the second H-shaped steel 42 constituting the specific support member 4 are subjected to the largest bending moment M at the axial one end 4A and the other end 4B rigidly joined to the first and second joined members 2A, 2B, and the bending moment M decreases as the axial center point 4C is approached. In view of this, in the specific support member 4, the first inner flange 411A of the first H-shaped steel 41 and the second inner flange 421A of the second H-shaped steel 42 are not joined in the non-welded region 4C1 including the axial center point 4C, so that the first welded portion 5A is formed in the first welded region 4A1 on the axial one end 4A side relative to the non-welded region 4C1, and the second welded portion 5B is formed in the second welded region 4B1 on the axial other end 4B side. By forming the first weld 5A and the second weld 5B in the first weld area 4A1 and the second weld area 4B1 where a large bending moment M acts, it is possible to ensure the strength B1 and C1 required to resist the horizontal load P1 borne by the specific support member 4.

Moreover, in the specific support member 4, the non-welded region 4C1 including the axial center point 4C where the bending moment M acting is small is an area where no weld is formed. This makes it possible to suppress the increase rate of the stiffness A1 from becoming excessively larger than the strength B1, C1 in terms of the increase rate of the stiffness A1 and the strength B1, C1 in response to the formation of the welds 5A, 5B on both sides of the non-welded region 4C1 in the specific support member 4. That is, in the specific support member 4, the decrease rate of the stiffness A1 becomes larger than the strength B1, C1 in response to the non-welded region 4C1. Therefore, it is possible to lower the stiffness A1 of the specific support member 4 while ensuring the strength B1, C1 on both sides of the non-welded region 4C1 in the specific support member 4. As a result, when the horizontal load P applied to the building structure 1 is distributed to each support member 3, 4 according to the magnitude of each of the stiffnesses of the reference support member 3 and the specific support member 4, it is possible to suppress the horizontal load P1 borne by the specific support member 4 from becoming excessively larger than the horizontal load P2 borne by the reference support member 3. As a result, the horizontal load P is distributed according to the magnitude of the strengths B1, C1 of the specific support members 4 and the strengths B2, C2 of the reference support members 3, which prevents the specific support members 4 from undergoing plastic deformation earlier than the reference support members 3, and effectively utilizes the strengths B1, C1 of the specific support members 4 and the strengths B2, C2 of the reference support members 3 to resist the horizontal load P, improving the earthquake resistance of the building structure 1.

In addition, since the horizontal load P1 borne by the specific support member 4 can be prevented from becoming excessively large relative to the horizontal load P2 borne by the reference support member 3, the load on the area supporting the specific support member 4 in the first and second join members 2A and 2B can be prevented from becoming excessively large relative to the area supporting the reference support member 3.

As described above, when a horizontal load P is applied to the building structure 1, the largest bending moment M acts on one end 4A and the other end 4B of the first H-shaped steel 41 and the second H-shaped steel 42 that constitute the specific support member 4. For this reason, in the first H-shaped steel 41 and the second H-shaped steel 42, when the horizontal load P1 borne by the specific support member 4 exceeds the yield strength B1 of the specific support member 4, plasticization gradually progresses from the one end 4A and the other end 4B toward the center point 4C. In order to suppress the progression of such plasticization, it is desirable to form the first welded portion 5A and the second welded portion 5B in the range where plasticization is expected.

Therefore, as shown in FIG. 6, in the first H-shaped steel 41 and the second H-shaped steel 42, the axial region length L21 of the first welded region 4A1 on the one end 4A side relative to the non-welded region 4C1 is set so that the first plasticization assumed region 4D1 is included within the first welded region 4A1. The first plasticization assumed region 4D1 is a region where plasticization is assumed around the one end 4A of the first H-shaped steel 41 and the second H-shaped steel 42. Similarly, the axial region length L22 of the second welded region 4B1 on the other end 4B side relative to the non-welded region 4C1 is set so that the second plasticization assumed region 4D2 is included within the second welded region 4B1. The second plasticization assumed region 4D2 is a region where plasticization is assumed around the other end 4B of the first H-shaped steel 41 and the second H-shaped steel 42.

In the first H-shaped steel 41 and the second H-shaped steel 42, the region length L31 in the axial direction of the first assumed plasticization region 4D1 and the region length L32 in the axial direction of the second assumed plasticization region 4D2 can be calculated based on the total length L1 of the specific support member 4 in the axial direction from one end 4A to the other end 4B, or the width dimension W1 in the width direction perpendicular to the axial direction of the specific support member 4. The region length L31 of the first assumed plasticization region 4D1 and the region length L32 of the second assumed plasticization region 4D2 are set to, for example, at least one-tenth the length of the total length L1 of the specific support member 4, or at least twice the length of the width dimension W1 of the specific support member 4.

The region length L21 of the first welding region 4A1 is not particularly limited as long as it is set so that the first plasticization assumed region 4D1 is included in the first welding region 4A1. The region length L21 of the first welding region 4A1 is set to, for example, a quarter of the total length L1 of the specific support member 4. Similarly, the region length L22 of the second welding region 4B1 is not particularly limited as long as it is set so that the second plasticization assumed region 4D2 is included in the second welding region 4B1. The region length L22 of the second welding region 4B1 is set to, for example, a quarter of the total length L1 of the specific support member 4. In this case, the region length L23 in the axial direction of the non-welded region 4C1 between the first welding region 4A1 and the second welding region 4B1 is set to a half of the total length L1 of the specific support member 4.

In this embodiment, as shown in FIG. 6, the first welded portion 5A in the first welding region 4A1 is formed to include one end 4A in the axial direction of the first H-shaped steel 41 and the second H-shaped steel 42. That is, in the first welding region 4A1, the first welded portion 5A extends in a continuous straight line from one end 4A in the axial direction of the first H-shaped steel 41 and the second H-shaped steel 42 to the center point 4C. Similarly, in the second welding region 4B1, the second welded portion 5B is formed to include the other end 4B in the axial direction of the first H-shaped steel 41 and the second H-shaped steel 42. That is, in the second welding region 4B1, the second welded portion 5B extends in a continuous straight line from the other end 4B in the axial direction of the first H-shaped steel 41 and the second H-shaped steel 42 to the center point 4C. In this way, in the first H-shaped steel 41 and the second H-shaped steel 42, the first welded portion 5A and the second welded portion 5B are formed including the axial end 4A and the other end 4B where the largest bending moment M acts, so that the strengths B1 and C1 required to resist the horizontal load P1 borne by the specific support member 4 can be more reliably secured.

In addition, in the first welding region 4A1, the first welded portion 5A is formed continuously over the entire axial direction of the first welding region 4A1. In this case, the weld length L21A in the axial direction of the first welded portion 5A is the same as the region length L21 of the first welding region 4A1. Similarly, in the second welding region 4B1, the second welded portion 5B is formed continuously over the entire axial direction of the second welding region 4B1. In this case, the weld length L22A in the axial direction of the second welded portion 5B is the same as the region length L22 of the second welding region 4B1. In this way, in the first H-shaped steel 41 and the second H-shaped steel 42, the first welded portion 5A and the second welded portion 5B are formed continuously over the entire welded areas 4A1, 4B1 on the axial end 4A side and the other end 4B side where a large bending moment M acts, so that the strengths B1, C1 required to resist the horizontal load P1 borne by the specific support member 4 can be more reliably secured.

In addition, in the first H-shaped steel 41 and the second H-shaped steel 42, the first welded portion 5A formed in the first welding area 4A1 and the second welded portion 5B formed in the second welding area 4B1 are formed so as to be symmetrical in the axial direction. This allows the specific support member 4 to support the horizontal load P evenly at each of the one end 4A and the other end 4B in the axial direction.

As described above, the first through hole 412A is formed in the first web 412 of the first H-shaped steel 41, and the second through hole 422A is formed in the second web 422 of the second H-shaped steel 42. The first through hole 412A is formed in at least the first welded region 4A1 and the second welded region 4B1 on both sides of the non-welded region 4C1 in the first web 412. In other words, the first through hole 412A may be formed in each of the non-welded region 4C1, the first welded region 4A1, and the second welded region 4B1 in the first web 412, or may be formed only in the first welded region 4A1 and the second welded region 4B1. Similarly, the second through hole 422A is formed in at least the first welded region 4A1 and the second welded region 4B1 on both sides of the non-welded region 4C1 in the second web 422.

When a horizontal load P is applied to the building structure 1, there is a risk that plastic deformation may easily occur around the first through hole 412A and the second through hole 422A in the first H-shaped steel 41 and the second H-shaped steel 42. Therefore, in the first welding area 4A1, the first welded portion 5A is formed in a range that covers at least half (preferably the entirety) of the first through hole 412A and the second through hole 422A arranged in the first welding area 4A1 when viewed from a direction perpendicular to the axial direction. Similarly, in the second welding area 4B1, the second welded portion 5B is formed in a range that covers at least half (preferably the entirety) of the first through hole 412A and the second through hole 422A arranged in the second welding area 4B1 when viewed from a direction perpendicular to the axial direction. This makes it possible to suppress the occurrence of plastic deformation around the first through hole 412A and the second through hole 422A.

In this embodiment, the weld length L21A of the first welded portion 5A and the weld length L22A of the second welded portion 5B are set so that the rigidity ratio AR and the yield strength ratio BR are approximately equal. Specifically, the weld length L21A of the first welded portion 5A and the weld length L22A of the second welded portion 5B are set so that the rigidity ratio AR and the yield strength ratio BR satisfy, for example, the following formula (1).
1≦(rigidity ratio AR/strength ratio BR)≦1.5... (1)

The stiffness ratio AR indicates the ratio (A1/A2) of the stiffness A1 of the specific support member 4 to the stiffness A2 of the reference support member 3. The strength ratio BR indicates the ratio (B1, C1/B2, C2) of the strength B1, C1 of the specific support member 4 to the strength B2, C2 of the reference support member 3.

If the ratio of the stiffness A3 of the conventional support member to the stiffness A2 of the reference support member 3 is taken as the conventional stiffness ratio, and the ratio of the strengths B3, C3 of the conventional support member to the strengths B2, C2 of the reference support member 3 is taken as the conventional strength ratio, then (conventional stiffness ratio/conventional strength ratio) exceeds "1.5" and does not satisfy the above formula (1).

As described above, the weld length L21A of the first welded portion 5A and the weld length L22A of the second welded portion 5B are set so that the stiffness ratio AR and the strength ratio BR are approximately equal and satisfy the above formula (1). This makes it possible to more reliably prevent the rate of increase in stiffness A1 and strength B1, C1 of the specific support member 4 relative to the reference support member 3 from becoming excessively larger than the strengths B1, C1. Therefore, when the horizontal load P applied to the building structure 1 is distributed to each support member 3, 4 according to the magnitude of each of the stiffness of the reference support member 3 and the specific support member 4, it is possible to more reliably prevent the horizontal load P1 borne by the specific support member 4 from becoming excessively larger than the horizontal load P2 borne by the reference support member 3.

The above describes the building structure 1 according to an embodiment of the present invention, but the present invention is not limited to this, and the following modified embodiments can be adopted, for example.

In the above embodiment, the first and second H-shaped steels 41 and 42 constituting the specific support member 4 are described as being continuously formed over the entire welded areas 4A1 and 4B1 on the axial end 4A side and the other end 4B side of the first and second H-shaped steels 41 and 42, respectively, but the present invention is not limited thereto. As shown in FIG. 7, the first and second welded areas 5A and 5B do not have to be formed over the entire first and second welded areas 4A1 and 4B1 in the axial direction. In this case, the weld length L21A of the first welded area 5A is shorter than the area length L21 of the first welded area 4A1, and the weld length L22A of the second welded area 5B is shorter than the area length L22 of the second welded area 4B1.

In the above embodiment, the first and second H-shaped steels 41 and 42 constituting the specific support member 4 are described as being formed with the first and second welded portions 5A and 5B including the axial one end 4A and the other end 4B, but the present invention is not limited thereto. As shown in FIG. 8, the first and second welded portions 5A and 5B do not have to be formed including the axial one end 4A and the other end 4B of the first and second H-shaped steels 41 and 42. In this case, in the first welding region 4A1, the first welded portion 5A extends from a position away from the axial one end 4A of the first and second H-shaped steels 41 and 42 toward the center point 4C. Similarly, in the second welding region 4B1, the second welded portion 5B extends from a position away from the axial other end 4B of the first and second H-shaped steels 41 and 42 toward the center point 4C.

In the above embodiment, the first and second H-shaped steels 41 and 42 constituting the specific support member 4 are described as having a first welded portion 5A extending in a continuous straight line in the first welding region 4A1 and a second welded portion 5B extending in a continuous straight line in the second welding region 4B1, but the present invention is not limited to this. As shown in FIG. 9, the first welded portion 5A may have a plurality of welded portions 5A1 formed at intervals in the axial direction in the first welding region 4A1. Similarly, the second welded portion 5B may have a plurality of welded portions 5B1 formed at intervals in the axial direction in the second welding region 4B1.

In addition, in the above embodiment, a mode has been described in which the first through hole 412A is formed in the first web 412 and the second through hole 422A is formed in the second web 422 in the first H-shaped steel 41 and the second H-shaped steel 42 constituting the specific support member 4, but the present invention is not limited to this. A through hole may not be formed in the second web 422. Also, a through hole may not be formed in each of the first web 412 and the second web 422.

1 Building structure 2A First joined member 2B Second joined member 3 Reference support member 4 Specific support member 41 First H-shaped steel 411A, 411B First flange 412 First web 412A First through hole 42 Second H-shaped steel 421A, 421B Second flange 422 Second web 422A Second through hole 4A1 First welded area 4B1 Second welded area 4C Center point 4C1 Non-welded area (predetermined area)
5A First welded portion 5B Second welded portion

Claims (6)

A reference support member having a predetermined rigidity and supporting a load;
A specific support member having a higher rigidity than the reference support member and supporting a load;
a first joined member to which one axial end of the reference support member and one axial end of the specific support member are rigidly joined;
a second joined member to which the other axial end of the reference support member and the other axial end of the specific support member are rigidly joined,
The specific support member is
a first H-shaped steel having a pair of first flanges and a first web connecting the first flanges to each other;
a second H-shaped steel having a pair of second flanges and a second web connecting the second flanges to each other;
one of the pair of first flanges and one of the pair of second flanges are welded to each other by a weld portion with outer surfaces thereof in contact with each other,
A building structure, wherein the welded portions are formed only on both sides of a specified region including the axial center points of the first H-shaped steel and the second H-shaped steel, so that one of the pair of first flanges and one of the pair of second flanges are not joined in the specified region including the axial center points of the first H-shaped steel and the second H-shaped steel. The welded portion is
A first welded portion formed including one end portion in the axial direction of the first H-shaped steel and the second H-shaped steel;
The building structure according to claim 1 , further comprising: a second weld portion formed including the other axial end portion of the first H-shaped steel and the other axial end portion of the second H-shaped steel. The building structure according to claim 1 or 2, in which the welded portion is formed continuously over the entire area on both sides of the specified area. The building structure according to any one of claims 1 to 3, wherein the welds are formed symmetrically in the axial direction on both sides of the specified region. The building structure according to any one of claims 1 to 4, in which the axial length of the weld is set so that the stiffness ratio indicating the ratio of the stiffness of the specific support member to the stiffness of the reference support member is approximately equal to the strength ratio indicating the ratio of the strength of the specific support member to the strength of the reference support member. The first web has through holes formed on at least both sides of the predetermined region, the through holes penetrating the first web in a thickness direction thereof,
The building structure according to any one of claims 1 to 5, wherein the welded portion is formed in an area that covers at least half of the through hole when viewed from a direction perpendicular to the axial direction.

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