JP2023135445A - Non-diaphragm brace structure - Google Patents

Abstract

To provide a non-diaphragm brace structure in which all of beam-column connection parts can be arranged as non-diaphragm connection parts on the same structure plane of the brace structure avoiding overspecification and economically.SOLUTION: In a brace structure, addition to a skeleton in a frame structure obtained by rigidly coupling a rectangular steel tube column 2 and a reinforcement beam (a steel beam 3), a brace 4 which is a diagonal member is provided to be loaded with horizontal force, all of connection parts of the rectangular steel tube column 2 and the reinforcement beam (the steel beam 3) in the same structure plane are non-diaphragm thick rectangular steel tube 1 consisting of the rectangular steel tube column in a hollow cross section thicker than other parts of the rectangular steel 1 and non-diaphragm thick rectangular steel tube 1 is arranged in the same cross section shape both for connection parts to which the brace 4 is connected and connection parts to which the brace 4 is not connected.SELECTED DRAWING: Figure 1

Description

The present invention relates to a brace structure for steel frames, and more particularly, to a non-diaphragm brace structure that does not adopt a diaphragm type or an inner diaphragm type through the column-beam joint in the brace structure, but uses a non-diaphragm type with a hollow cross section that does not require a diaphragm. It is.

The steel structure of a building is generally a rigid frame structure in which columns made of square steel pipes and beams made of H-shaped steel are rigidly connected (rigidly connected). However, since the cross-sections of members can be designed rationally, in addition to the rigid frame structure of columns and beams, brace structures are also known in which diagonal members made of steel called ``braces'' are installed, and the braces bear the seismic force.

For example, Patent Document 1 discloses a V-shaped left brace body having a left end joint where a first left brace connected to the left joint and a second left brace connected to the upper beam are joined at their ends to each other. a left connecting brace connected to the left end joint, a first right brace connected to the right joint, and a second right brace connected to the upper beam; constitute a V-shaped right brace body having a right end joint portion whose ends are joined to each other, and a right connecting brace joined to the right end joint portion is joined to the lower end portion of the right column, and A column-beam frame reinforcement structure in which the left connecting brace and the right connecting brace are each composed of buckling stiffening braces is disclosed (Claim 1 of Patent Document 1, paragraphs [0015] to [0018] of the specification). , see Figures 1 and 2 of the drawings).

On the other hand, the joints between columns made of square steel pipes and beams made of H-shaped steel in a rigid frame structure are constructed using a through diaphragm type to prevent the hollow square steel pipe columns from being crushed by the stress transmitted from the beams at the joints. As an inner diaphragm type, a diaphragm is installed inside the hollow section of a square steel pipe column, and the column and beam are integrated. However, such through-diaphragm type or inner diaphragm type column-beam joints have a problem in that welding and joint shapes are complicated, requiring time and effort in processing, UT inspection, and quality control, and increasing manufacturing costs. Therefore, a thick-walled square steel tube that is thicker than the square steel tube column is installed as a non-diaphragm member at the joint with the beam that connects to the square steel tube column, creating a non-diaphragm type column that eliminates the need for a diaphragm in the hollow part of the square steel tube column. A beam joint was proposed.

For example, in Patent Document 2, in a joint structure formed between a square steel pipe column, an H-shaped steel beam, and a brace proposed by the applicant of the present application, a thick-walled steel pipe joined to the end of the square steel pipe column is disclosed. A non-diaphragm column-beam joint structure in which at least the H-shaped steel beam is joined to the thick-walled steel pipe is disclosed (Claim 1 of Patent Document 2, paragraphs [0009] to [0015] of the specification). , see Figure 1 of the drawings, etc.).

However, in the brace structure, the axial force of the brace acts in the axial direction of the beam, resulting in a decrease in the yield bending strength and total plastic bending strength of the beam. Accordingly, when a non-diaphragm type column-beam joint is adopted for a brace structure, the beam end joint of the non-diaphragm type column-beam joint also undergoes yield bending due to the axial force of the brace acting from the beam. Yield strength and total plastic bending strength will decrease. Therefore, in the brace structure, there is a problem in that a column-beam joint to which no brace is connected cannot be a non-diaphragm joint.

Furthermore, in the same structural face of a steel brace structure, it would be extremely time-consuming and unrealistic to judge whether to use a non-diaphragm type or a conventional type (through-diaphragm type or inner diaphragm type) depending on the joint (joint) each time. isn't it. Furthermore, as described above, the conventional type of column-beam joint has the problem that it is complicated and requires time and effort in processing, UT inspection, and quality control, and increases manufacturing costs. In addition, there is a problem in that it takes time and effort to change the beam composition of two beams connected in the right and left directions or in the orthogonal directions of the X and Y directions, which is an advantage of the non-diaphragm type.

Additionally, the Architectural Institute of Japan's ``Steel Structure Joint Design Guidelines'', which describes the design method for non-diaphragm type joints, currently does not specify how to handle the axial force that acts on non-diaphragm thick-walled rectangular steel pipes from beams to columns. It has not been. Therefore, it is not possible to calculate the yield strength of non-diaphragm thick-walled rectangular steel pipes, and it is not possible to confirm whether a safety factor can be secured for the strength of the beam.

In addition, one of the two beams that connect to the non-diaphragm thick-walled square steel pipe in the X and Y directions is not connected to a brace, so a conventional joint is used, and the other beam is connected to a brace. Therefore, if a non-diaphragm type joint is adopted, it is necessary to match the size of the two beams (beam composition). This is because if the sizes of the beams are not matched, it is not possible to adopt a non-diaphragm type, and it is necessary to use a conventional type of joint where a diaphragm is provided at the joint. Therefore, the size of the two beams has to be adjusted to the larger one, which results in over-spec and becomes uneconomical.

Furthermore, the axial force acting on the beam from the brace changes depending on the angle at which the brace is attached. Its size is approximately 0.1 to 0.3 of the axial force ratio of the beam. Here, the axial force ratio refers to the ratio of the acting axial force to the yield axial force capacity of the beam, ie, the axial force ratio=(acting axial force)/(yield axial force capacity of the beam).

JP2020-76208A Utility model registration No. 3232594

Therefore, the present invention was devised in view of the above-mentioned problems, and its purpose is to economically connect all column-beam joints in the same structural plane of a brace structure without over-spec. An object of the present invention is to provide a non-diaphragm brace structure that can be a non-diaphragm type joint.

The non-diaphragm brace structure according to the first invention is a brace structure in which a horizontal force is borne by providing diagonal braces in addition to a frame of a rigid frame structure in which square steel pipe columns and steel beams are rigidly connected. The joints between the square steel pipe column and the beam are all non-diaphragm thick-wall square steel pipes made of square steel pipes with a hollow cross section that are thicker than other parts of the square steel pipe column, and the non-diaphragm thick-wall A square steel pipe is characterized in that both the joints to which braces are connected and the joints to which braces are not connected have the same cross-sectional shape.

The non-diaphragm brace structure according to the second invention is a brace structure in which horizontal force is borne by providing diagonal braces in addition to a frame of a rigid frame structure in which square steel pipe columns and steel beams are rigidly connected. The joints between the square steel pipe column and the beam are all non-diaphragm thick-walled square steel pipes made of square steel pipes with a hollow cross section that are thicker than other parts of the square steel pipe column, and the axial force acting from the beam is The yield bending strength jcMy of the beam end joint of the non-diaphragm thick-walled rectangular steel pipe satisfies the following formula (1) when considering the axial force acting from the beam. The total plastic bending strength jcMp of the beam end joint of the steel pipe satisfies the following formula (2), and the yield bending strength jMy of the beam end joint of the non-diaphragm thick square steel pipe satisfies the following formula (3), The non-diaphragm brace structure is characterized in that the total plastic bending strength jMp of the beam end joint of the non-diaphragm thick-walled rectangular steel pipe satisfies the following formula (4).
jcMy≧α×bcMy...Formula (1)
jcMp≧β×bcMp...Formula (2)
jMy≧γ×bMy...Formula (3)
jMp≧δ×bMp...Equation (4)
jcMy: Yield bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
jcMp: Total plastic bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
bcMy: Yield bending strength of the beam (considering the axial force acting on the beam)
bcMp: Total plastic bending strength of the beam (considering the axial force acting on the beam)
jMy: Yield bending strength of non-diaphragm beam end joints
jMp: Total plastic bending strength of non-diaphragm beam end joint
bMy: Yield bending strength of beam
bMp: Total plastic bending strength of the beam α: Joint coefficient 1.0 or more β: Joint coefficient 1.0 or more γ: Joint coefficient 1.0 or more δ: Joint coefficient 1.0 or more

In the non-diaphragm brace structure according to a third invention, in either the first invention or the second invention, the width-thickness ratio D/t of the outer diameter D and the wall thickness t of the non-diaphragm thick-walled rectangular steel pipe is determined by the following formula: It is characterized by satisfying (5).
D/t<10.90...Formula (5)

In the non-diaphragm brace structure according to a fourth aspect of the present invention, in the first to third aspects, the cross-sectional shape of the non-diaphragm thick-walled rectangular steel pipe has a tapered surface formed on the inner surface such that the cross-sectional shape becomes thicker as it approaches the inner corner. It is characterized by

In the non-diaphragm brace structure according to a fifth invention, in any one of the first to fourth inventions, a column shear span ratio ( _c L / 2 _c D) of the square steel pipe column is 2.5 or more, and , the length L of the non-diaphragm thick-walled rectangular steel pipe is 1500 mm or less. Here, _c L: Length of the square steel pipe column, _c D: Outer diameter of the square steel pipe column

According to the first to fifth inventions, all the column-beam joints can be made into non-diaphragm joints in the same structural plane of the brace structure economically without over-spec. Therefore, according to the first to fifth inventions, there is no need to judge and use either the non-diaphragm type or the conventional type (through-diaphragm type or inner diaphragm type) depending on the connection each time, which saves design effort. can be converted into In addition, according to the first to fifth inventions, it is possible to use a non-diaphragm type for connections to which braces are not connected, making it easier to apply the non-diaphragm type to inclined beams and step beams, which increases flexibility in design. increases.

FIG. 1(a) is an elevational view schematically showing the structure of the right-sloping non-diaphragm brace structure according to the first embodiment, and FIG. 1(b) shows the non-diaphragm type and the conventional type (through-type). FIG. 2 is an elevational view schematically showing the construction of a conventional downward-sloping brace structure in which a diaphragm type or inner diaphragm type joint is mixed. FIG. 2 is a partially enlarged elevational view showing the vicinity of the gate A in FIG. 1(a). FIG. 3 is a partially enlarged elevational view showing the vicinity of the gate B in FIG. 1(a). FIG. 4 is a horizontal cross-sectional view showing a non-diaphragm thick-walled square steel pipe, in which (a) represents the cross-sectional shape of 552 mm≧D≧250 mm, and (b) represents the cross-sectional shape of 252 mm≧D≧150 mm. There is. Further, FIG. 4(c) shows the cross-sectional shape of a non-diaphragm thick-walled rectangular steel pipe with a four-sided box formed by welding four flat steel plates. FIG. 5 is a vertical sectional view schematically showing a joint portion between a non-diaphragm thick-walled square steel pipe, a square steel pipe column, and a steel beam. FIG. 6 is a graph showing the relationship between D/t and D/B (B: beam width) for a 400N class steel beam (F=235N/mm ² ). FIG. 7(a) is an elevational view schematically showing the structure of the upward-sloping non-diaphragm brace structure according to the second embodiment, and FIG. 7(b) shows the non-diaphragm type and the conventional type (through-type). FIG. 2 is an elevational view schematically showing the construction of a conventional upward-sloping brace structure in which a diaphragm type or an inner diaphragm type joint is mixed. FIG. 8 is a partially enlarged elevational view showing the vicinity of the gate A in FIG. 7(a). FIG. 9 is a partially enlarged elevational view showing the vicinity of the gate B in FIG. 7(a). FIG. 10(a) is an elevational view schematically showing the structure of a V-shaped non-diaphragm brace structure according to the third embodiment, and FIG. 10(b) shows a non-diaphragm type and a conventional type (through-diaphragm brace structure). FIG. 2 is an elevational view schematically showing the construction of a conventional V-shaped brace structure in which joints of various types (inner diaphragm type or inner diaphragm type) are mixed. FIG. 11 is a partially enlarged elevational view showing the vicinity of the gate A in FIG. 10(a). FIG. 12 is a partially enlarged elevational view showing the vicinity of the joint C in FIG. 10(a). FIG. 13(a) is an elevational view schematically showing the construction of a K-shaped non-diaphragm brace structure according to the fourth embodiment, and FIG. 13(b) shows a non-diaphragm type and a conventional type (through-diaphragm brace structure). FIG. 2 is an elevational view schematically showing the construction of a conventional K-shaped brace structure in which joints of various types (inner diaphragm type and inner diaphragm type) are mixed. FIG. 14 is a partially enlarged elevational view showing the vicinity of the gate A in FIG. 13(a). FIG. 15 is a partially enlarged elevational view showing the vicinity of the gate C in FIG. 13(a).

Hereinafter, a non-diaphragm brace structure according to an embodiment of the present invention will be described in detail with reference to the drawings.

[First embodiment]
A non-diaphragm brace structure 11 according to a first embodiment of the present invention will be explained using FIGS. 1 to 6. FIG. 1(a) is an elevational view schematically showing the structure of a right-sloping non-diaphragm brace structure 11 according to the first embodiment, and FIG. 1(b) shows a non-diaphragm type and a conventional type ( FIG. 2 is an elevational view schematically showing the construction of a conventional downward-sloping brace structure in which joints (through-diaphragm type or inner diaphragm type) are mixed. Further, FIG. 2 is a partially enlarged elevational view showing the vicinity of Shiguchi A in FIG. 1(a), and FIG. 3 is a partially enlarged elevation view showing the vicinity of Shiguchi B in FIG. 1(a). It is an elevational view.

As shown in FIG. 1(a), a non-diaphragm brace structure 11 (hereinafter also simply referred to as "non-diaphragm brace structure 11") according to a first embodiment of the present invention includes a pair of left and right square steel pipe columns 2, 2. and a pair of upper and lower steel beams 3, 3 are rigidly connected to the frame of a rectangular frame-like rigid frame structure, and one brace 4, which is a diagonal member that slopes downward to the right, is provided to bear the horizontal force. It has a brace structure.

The non-diaphragm brace structure 11 has four joints A to D, which are column-beam joints between the square steel pipe column 2 and the steel beam 3, all having the same cross section, which is a non-diaphragm type joint. It is a non-diaphragm thick-walled square steel pipe 1 (non-diaphragm member).

On the other hand, as shown in FIG. 1(b), in the conventional downward-sloping brace structure 101, the joint B and the joint C to which the brace 4 is not connected are The handling of axial force acting on non-diaphragm thick-walled rectangular steel pipes 1 from beams to columns is not specified in the "Structural Joint Design Guidelines", and conventional types of columns with diaphragms such as through-diaphragm type or internal diaphragm type are not recommended. We had no choice but to use beam joint 1'.

(Square steel pipe column)
The square steel pipe column 2 is made of BCR (registered trademark: cold-roll-formed square steel pipe for building structures), BCP (registered trademark: cold-press-formed square steel pipe for building structures), or STKR (carbon steel steel pipe for general structure). Since it is a hollow steel tube and has no anisotropy, a square cross section is generally used (see also Figure 4). The non-diaphragm brace structure 11 according to the present embodiment will be explained by exemplifying a U column with a column size of outer diameter cD = 400 mm x wall thickness ct = 16 mm (□400 x 16). Note that the column member has a σy of 245 to 445 N/mm ² .

Of course, the rectangular steel pipe column according to the present invention is appropriately determined according to the structural design, and may have a rectangular cross section, and the column size is not limited to 400 x 16 square. However, as a general design range, the square steel pipe column 2 is □400×16, □350×12, □300×12, □250×9, □200×9, □175×9, □150×9 A certain degree has been adopted. Furthermore, BCR and BCP are symbols that mean identification, and there is no problem in using other symbols.

(steel beam)
The steel beam 3 is an H-beam made of rolled steel for general structures, rolled steel for welded structures, rolled steel for building structures, weather-resistant hot rolled steel for welded structures, etc. As shown in FIG. 31, a lower flange 32, and a web 33 connecting these. The non-diaphragm brace structure 11 according to the present embodiment will be explained using a narrow H-section steel (HY-600 x 200 x 12 x 19) as an example. In addition, the reference numeral 34 indicates a stiffening rib that is formed between the upper flange 31 and the lower flange 32 and that reinforces the web 33 so that it does not buckle, which corresponds to a reinforcing rib formed along the edge of the gusset plate 5, which will be described later. It is 34. The σy of the beam member is 245 to 445 N/mm ² .

Of course, the steel beam according to the present invention is also appropriately determined according to the structural design, similar to the square steel pipe column according to the present invention. However, as a general design range, the steel beam 3 is HY-600 x 200 x 12 x 19, H-500 x 200 x 10 x 16, H-500 x 200 x 10 x 16, H-500 x 200. ×10×16, H-450×200×9×14, H-350×175×7×11, H-300×150×6.5×9, H-300×150×6.5×9, H -300 x 150 x 6.5 x 9 approximately. Note that the steel beam 3 may be divided through splice plates.

(brace)
Like the steel beam 3, the brace 4 is an H-beam made of rolled steel for general structures, rolled steel for welded structures, rolled steel for architectural structures, weather-resistant hot rolled steel for welded structures, etc. (see Figure 2). ). However, it goes without saying that the brace according to the present invention is not limited to H-shaped steel, but may be other shaped steel such as angle-shaped steel. In short, the brace according to the present invention may be made of any steel material as long as it can be joined to the bracket, the non-diaphragm thick-walled square steel pipe 1, or the steel beam 3.

As shown in FIG. 2, the brace 4 is integrally joined to the non-diaphragm thick-walled rectangular steel pipe 1 and the steel beam 3 by welding via the gusset plate 5, and is rigidly connected (rigidly connected). In the illustrated embodiment, the brace 4 and the gusset plate 5 are welded and integrated, but they may be bolted together via a splice plate so as not to be angularly deformable. Moreover, the brace 4 may be divided via a splice plate.

(Non-diaphragm thick-walled square steel pipe)
Next, the non-diaphragm thick-walled rectangular steel pipe, which is a feature of the present invention, will be further explained using FIGS. 4 and 5. FIG. 4 is a horizontal cross-sectional view showing a non-diaphragm thick-walled rectangular steel pipe 1, in which (a) represents a cross-sectional shape of 552 mm≧D≧250 mm, and (b) represents a cross-sectional shape of 252 mm≧D≧150 mm. ing. Further, FIG. 5 is a vertical sectional view schematically showing a joint portion between the non-diaphragm thick-walled square steel pipe 1, the square steel pipe column 2, and the steel beam 3.

The non-diaphragm thick-walled square steel pipe 1 is a square steel pipe made of rolled steel material for architectural structures (SN490B), and as shown in FIGS. It has a hollow cross section. Specifically, the non-diaphragm thick-walled rectangular steel tube 1 according to the present embodiment is a hollow thick-walled rectangular steel tube without a diaphragm with an outer diameter D = 402 mm x wall thickness t = 36.9 mm.

Of course, the non-diaphragm thick-walled rectangular steel pipe according to the present invention can be appropriately determined depending on the structural design, and the horizontal cross section is not limited to □402×36.9. However, as a general design range, the outer diameter D of the non-diaphragm thick-walled square steel pipe 1 is approximately 402 mm, 352 mm, 302 mm, 252 mm, 202 mm, 177 mm, and 152 mm. In addition, since the wall thickness t also changes, the cross section of the non-diaphragm thick-walled rectangular steel pipe 1 is as shown in Fig. 4 (a) when the outer diameter D is 402 mm, 352 mm, 302 mm, and 252 mm, when channel steel is welded together. , when the outer diameter D is 202 mm, 177 mm, and 152 mm, the angle irons are welded together as shown in FIG. 4(b).

Although the number of welding points increases and the manufacturing process is time-consuming, as shown in FIG. It is also possible to form a four-sided BOX-shaped cross section by simply butting together flat steel plates and joining them by complete penetration welding.

In addition, as shown in FIG. 4(a), when the outside diameter D of the non-diaphragm thick-walled rectangular steel pipe 1 is 252 mm or more, the side where the weld bead 1a is formed has a cross-sectional shape from the center to the inside corner. A tapered surface 1b is formed on the inner surface so that it becomes thicker as it approaches. A stiffening effect can be expected by providing a taper. Therefore, the effective outer diameter when calculating D/t changes depending on whether there is a taper, and D/t can be calculated using D'.

Further, as shown in FIG. 5, all the column-beam joints of the non-diaphragm brace structure 11 are non-diaphragm type joints, and the number of complete penetration welded parts is 12 sides at maximum. For this reason, the non-diaphragm brace structure 11 differs from the conventional brace structure 101 in which a diaphragm is installed, such as a through diaphragm type or an inner diaphragm type, in the column-beam joint 1', which greatly reduces the number of complete penetration welding points. can do. Therefore, the number of UT inspections (Ultrasonic Testing) can be significantly reduced, and as shown in Fig. Even if there is a problem, there will be no discrepancy between the joints. In addition, since there is no through diaphragm, there is no protrusion of the diaphragm, making it easy to use with non-scallop construction methods.

In addition, as described in the background art, the joints B and C of the conventional brace structure 101 had no choice but to be the column-beam joint 1' where a conventional type diaphragm was provided. . However, in the non-diaphragm brace structure 11, since the joint between the joint B and the joint C is a non-diaphragm type, the yield bending strength jcMy of the beam end joint when considering the axial force acting from the steel beam 3 must satisfy the following formula (1), and the total plastic bending strength jcMp must satisfy the following formula (2).

jcMy≧α×bcMy...Formula (1)
jcMp≧β×bcMp...Formula (2)
jcMy: Yield bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
jcMp: Total plastic bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
bcMy: Yield bending strength of the beam (considering the axial force acting on the beam) (Note 1)
bcMp: Total plastic bending strength of the beam (considering the axial force acting on the beam) (Note 1)
α: Joint coefficient 1.0 or more β: Joint coefficient 1.0 or more The proof strength of each steel beam 3 is σy = 259N/mm ² (beam 400N class), σy = 330N/mm ² (beam 490N class) ). In addition, the joint coefficients α and β are the safety factors for safely transmitting the stress acting on the beam and ensuring that the non-diaphragm beam end joint does not enter a fully plastic state until plastic deformation of the beam occurs. This is assumed to vary depending on variations in material strength, etc. The axial force ratio of the beam was set to 0.3. The yield bending strength was defined as the load at which the tangential stiffness in the load-deformation relationship graph of each member became 1/3 of the initial stiffness, and the total plastic bending strength was defined as the load at 1/6.
Note 1: Quoted from Architectural Institute of Japan “Steel Structure Plasticity Design Guidelines”

Furthermore, the joints A and D of the non-diaphragm brace structure 11 are of a non-diaphragm type, similar to the non-diaphragm type column-beam joint structure described in Patent Document 2. To this end, in the non-diaphragm brace structure 11, the non-diaphragm thick-walled rectangular steel pipes 1 of the joint A and the joint D must have a yield bending strength jMy of the beam end joint that satisfies the following formula (3) and a total plasticity The bending strength jMp needs to satisfy the following formula (4).

jMy≧γ×bMy...Formula (3)
jMp≧δ×bMp...Equation (4)
jMy: Yield bending strength of non-diaphragm beam end joints
jMp: Total plastic bending strength of non-diaphragm beam end joint
bMy: Yield bending strength of beam (Note 1)
bMp: Total plastic bending strength of beam (Note 1)
γ: Joint coefficient 1.0 or more δ: Joint coefficient 1.0 or more The proof strength of each steel beam 3 is σy = 259N/mm ² (beam 400N class), σy = 330N/mm ² (beam 490N class) ). Also, here, the joint coefficients γ and δ, like the joint coefficients α and β, safely transmit the stress acting on the beam, and the non-diaphragm beam end joint is in a fully plastic state until plastic deformation of the beam occurs. It is a safety factor for designing to avoid the above-mentioned conditions, and it is assumed to vary depending on variations in material strength, etc. The yield bending strength was defined as the load at which the tangential stiffness in the load-deformation relationship graph of each member became 1/3 of the initial stiffness, and the total plastic bending strength was defined as the load at 1/6.
Note 1: Quoted from Architectural Institute of Japan “Steel Structure Plasticity Design Guidelines”

注１：日本建築学会「鋼構造塑性設計指針」より引用

Note 1: Quoted from Architectural Institute of Japan “Steel Structure Plasticity Design Guidelines”

In the non-diaphragm brace structure 11, the non-diaphragm thick-walled rectangular steel pipe 1 has four joints A to D all having the same cross-sectional shape. Therefore, both the joint to which the brace is connected and the joint to which the brace is not connected have the same cross-sectional shape. That is, in the non-diaphragm brace structure 11, the non-diaphragm thick-walled rectangular steel pipe 1 needs to satisfy all of the above-mentioned formulas (1) to (4).

Furthermore, from the calculation results shown in Tables 2 and 3 below, when the width-thickness ratio D/t becomes 10.90 or more, it becomes difficult to ensure the deformation performance of the entire building. It is preferable that the ratio D/t satisfies the following formula (5). Note that, from Tables 2 and 3, a realistic lower limit value of the width-thickness ratio D/t is considered to be 8.00 or more.
D/t<10.90...Formula (5)

In addition, the non-diaphragm thick-walled square steel pipe 1 has greater rigidity than the square steel pipe column 2, and when the ratio of the total length L of the non-diaphragm thick-walled square steel pipe 1 to the layer is large, the column This will change the deformation performance (see Figure 5, etc.). Therefore, it is preferable that the column shear span ratio (cL/2cD) of the above-mentioned square steel pipe column 2 is 2.5 or more, and the total length L of the non-diaphragm thick-walled square steel pipe 1 is 1500 mm or less.

In other words, it is preferable that the following expressions (6) and (7) be satisfied.
cL/2cD≧2...Formula (6)
Here, cL: length of the square steel pipe column 2, cD: outer diameter of the square steel pipe column 2 L≦1500mm...Equation (7)
Here, it goes without saying that the total length L of the non-diaphragm thick-walled rectangular steel pipe 1 is greater than or equal to the beam length of the largest beam of the steel beams 3 to be joined.

(Judgment of pass/fail of structural calculation based on width-thickness ratio D/t of non-diaphragm thick-walled rectangular steel pipe)
Next, while the outside diameter D of the non-diaphragm thick-walled rectangular steel pipe 1 is within the generally used range of 152 mm to 402 mm, the wall thickness t is variously changed, and the equations (1) to ( Using 4), consider the case where axial force (axial force ratio 0.3) acts on the steel beam when joint coefficient α = jMy / bMy = 1.0 and joint coefficient β = jcMp / bcMp = 1.3. Tables 2 and 3 below show whether or not the structure is acceptable (OK) in terms of structural calculations. Table 2 is a calculation example (α=1.0, β=1.3, γ=1.0, δ=1.3) when the steel beam is 400N (F=235N/mm ² ). 3 is a calculation example (α=1.0, β=1.3, γ=1.0, δ=1.3) when the steel beam is 490N (F=325N/mm ² ). The description of "new" in the table is an embodiment of the present invention that passed the test.

Comparing No. 23 and No. 24 in Tables 2 and 3, the joint coefficients α and γ are 1.00 or less, and β and δ are 1.30 or less. This indicates that the yielding of the beam end joint of the non-diaphragm thick-walled rectangular steel pipe 1 precedes the yielding of the steel beam 3, indicating that the deformation performance of the steel beam 3 cannot be fully demonstrated. Moreover, the same tendency is observed when the outer diameter D is different. Therefore, from the calculation results shown in Tables 2 and 3, when the width-thickness ratio D/t becomes 10.90 or more, it becomes difficult to ensure the deformation performance of the entire building. /t is preferably less than 10.90.

Furthermore, when the results in Table 2 are graphed, the relationship between D/t and D/B (B: beam width) for a 400N class steel beam (F=235N/mm ² ) is shown in the graph in Figure 6. , it can be seen that the width-thickness ratio D/t of 10.90 has critical significance.

[Second embodiment]
Next, a non-diaphragm brace structure 12 (hereinafter also simply referred to as "non-diaphragm brace structure 12") according to a second embodiment of the present invention will be described using FIGS. 7 to 9. The non-diaphragm brace structure 12 differs from the non-diaphragm brace structure 11 described above mainly in that the way the brace 4 is attached is different, so this point will be mainly explained, and the same components will be given the same reference numerals. The explanation will be omitted.

Note that FIG. 7(a) is an elevational view schematically showing the structure of the upward-sloping non-diaphragm brace structure 11 according to the second embodiment, and FIG. FIG. 2 is an elevational view schematically showing the construction of a conventional upward-sloping brace structure in which various types of joints (through-diaphragm type or inner diaphragm type) are mixed. 8 is a partially enlarged elevational view showing the vicinity of Shiguchi A in FIG. 7(a), and FIG. 9 is a partially enlarged elevation view showing the vicinity of Shiguchi B in FIG. 7(a). It is an elevational view.

As shown in FIG. 7(a), the non-diaphragm brace structure 12 has a rectangular frame-like rigid frame structure in which a pair of left and right square steel pipe columns 2, 2 and a pair of upper and lower steel beams 3, 3 are rigidly connected. One brace 4, which is a diagonal member that rises to the right, is provided on the frame to bear the horizontal force, resulting in a brace structure that rises to the right.

As shown in FIGS. 7 to 9, like the non-diaphragm brace structure 11 described above, this non-diaphragm brace structure 12 is also constructed from a joint A to a joint between a square steel pipe column 2 and a steel beam 3. The four joints of the mouth D are all non-diaphragm joints, which are non-diaphragm thick-walled rectangular steel pipes 1 (non-diaphragm members) having the same cross-sectional shape.

On the other hand, as shown in FIG. 7(b), in the conventional upward-sloping brace structure 102, the joint A and the joint D to which the brace 4 is not connected are The handling of axial force acting on non-diaphragm thick-walled rectangular steel pipes 1 from beams to columns is not specified in the "Structural Joint Design Guidelines", and conventional types of columns with diaphragms such as through-diaphragm type or internal diaphragm type are not recommended. We had no choice but to make the beam joint 1', which forced us to overspec.

However, according to the non-diaphragm brace structure 12, the connections A and D to which the braces are not connected can also be made of the non-diaphragm type, making it easier to apply the non-diaphragm type to inclined beams and stepped beams, making it easier to design. Increased freedom.

[Third embodiment]
Next, a non-diaphragm brace structure 13 (hereinafter also simply referred to as "non-diaphragm brace structure 13") according to a third embodiment of the present invention will be described using FIGS. 10 to 12. The non-diaphragm brace structure 13 differs from the above-described non-diaphragm brace structure 11 mainly in the number of braces 4 and the way they are attached, so we will mainly explain this point and explain that the same structure is the same. A reference numeral is given and the explanation is omitted.

Note that FIG. 10(a) is an elevational view schematically showing the structure of the V-shaped non-diaphragm brace structure 11 according to the third embodiment, and FIG. FIG. 2 is an elevational view schematically showing the construction of a conventional V-shaped brace structure in which joints (through-diaphragm type or inner diaphragm type) are mixed. Further, FIG. 11 is a partially enlarged elevational view showing the vicinity of Shiguchi A in FIG. 10(a), and FIG. 12 is a partially enlarged elevation view showing the vicinity of Shiguchi C in FIG. 10(a). It is an elevational view.

As shown in FIG. 10(a), the non-diaphragm brace structure 13 has a rectangular frame-like rigid frame structure in which a pair of left and right square steel pipe columns 2, 2 and a pair of upper and lower steel beams 3, 3 are rigidly connected. It has a V-shaped brace structure in which two braces 4, 4, which are V-shaped diagonal members, are provided on the frame to bear horizontal force.

As shown in FIGS. 10 to 12, like the non-diaphragm brace structure 11 described above, this non-diaphragm brace structure 13 also has a structure that extends from the joint A, which is the column-beam joint between the square steel pipe column 2 and the steel beam 3. The four joints of the mouth D are all non-diaphragm joints, which are non-diaphragm thick-walled rectangular steel pipes 1 (non-diaphragm members) having the same cross-sectional shape. Note that the two braces 4, 4 and the steel beam 3 are connected via a gusset plate (not shown) as in the past.

On the other hand, as shown in FIG. 10(b), in the conventional V-shaped brace structure 103, the joints C and D to which the brace 4 is not connected are The handling of axial force acting on non-diaphragm thick-walled rectangular steel pipes 1 from beams to columns is not specified in the "Joint Design Guidelines", and conventional types of columns and beams with diaphragms, such as through-diaphragm type or internal diaphragm type, are not specified. We had no choice but to make the joint part 1'.

However, according to the non-diaphragm brace structure 13, the connections C and D to which the braces are not connected can also be made of the non-diaphragm type, making it easier to apply the non-diaphragm type to inclined beams and step beams, and improving the design. Increased freedom.

[Fourth embodiment]
Next, a non-diaphragm brace structure 14 (hereinafter also simply referred to as "non-diaphragm brace structure 14") according to a fourth embodiment of the present invention will be described using FIGS. 13 to 15. The non-diaphragm brace structure 14 differs from the non-diaphragm brace structure 13 described above mainly in that the way the brace 4 is attached is different, so this point will be mainly explained, and the same components will be given the same reference numerals. The explanation will be omitted.

Note that FIG. 13(a) is an elevational view schematically showing the construction of the K-shaped non-diaphragm brace structure 14 according to the fourth embodiment, and FIG. 13(b) is an elevational view schematically showing the construction of the K-shaped non-diaphragm brace structure 14 according to the fourth embodiment, and FIG. 13(b) shows the non-diaphragm type and the conventional type. FIG. 2 is an elevational view schematically showing the construction of a conventional K-shaped brace structure in which joints (through-diaphragm type or inner diaphragm type) are mixed. Further, FIG. 14 is a partially enlarged elevational view showing the vicinity of Shiguchi A in FIG. 13(a), and FIG. 15 is a partially enlarged elevation view showing the vicinity of Shiguchi C in FIG. 14(a). It is an elevational view.

As shown in FIG. 13(a), the non-diaphragm brace structure 14 has a rectangular frame-like rigid frame structure in which a pair of left and right square steel pipe columns 2, 2 and a pair of upper and lower steel beams 3, 3 are rigidly connected. It is a K-shaped brace structure in which a frame and two braces 4, 4, which are K-shaped diagonal members, are provided to bear horizontal force.

As shown in FIGS. 13 to 15, like the non-diaphragm brace structure 13 described above, this non-diaphragm brace structure 14 is also constructed from a joint A to a joint between a square steel pipe column 2 and a steel beam 3. The four joints of the mouth D are all non-diaphragm joints, which are non-diaphragm thick-walled rectangular steel pipes 1 (non-diaphragm members) having the same cross-sectional shape. Note that, similarly to the non-diaphragm brace structure 13, the two braces 4, 4 and the steel beam 3 are connected via a gusset plate (not shown) as in the past.

On the other hand, as shown in FIG. 13(b), in the conventional K-shaped brace structure 104, the joint A and the joint B to which the brace 4 is not connected are The handling of axial force acting on non-diaphragm thick-walled rectangular steel pipes 1 from beams to columns is not specified in the "Joint Design Guidelines", and conventional types of columns and beams with diaphragms, such as through-diaphragm type or internal diaphragm type, are not specified. We had no choice but to make the joint part 1'.

However, according to the non-diaphragm brace structure 14, the connections A and B to which the braces are not connected can also be made of the non-diaphragm type, making it easier to apply the non-diaphragm type to inclined beams and step beams, and improving the design. Increased freedom.

According to the non-diaphragm brace structures 11 to 14 according to the embodiments of the present invention described above, all the column-beam joints in the same structural plane of the brace structure can be economically connected to non-diaphragm braces with the same cross-sectional shape without over-spec. It can be a type of joint.

In addition, according to the non-diaphragm brace structures 11 to 14, there is no need to judge and use either the non-diaphragm type or the conventional type (through-diaphragm type or inner diaphragm type) each time depending on the connection, which saves design effort. can do.

Moreover, according to the non-diaphragm brace structures 11 to 14, all the column-beam joints to which the brace 4 is not connected can be made of the non-diaphragm type, making it easier to apply the non-diaphragm type to inclined beams and stepped beams. Increased freedom in design.

The non-diaphragm brace structures 11 to 14 according to the embodiments of the present invention have been described in detail above, but the embodiments described above or shown in the drawings all represent one embodiment of the present invention. It's nothing more than that. Therefore, the technical scope of the present invention should not be interpreted to be limited by the illustrated embodiments.

11-14: Non-diaphragm brace structure 101-104: Conventional brace structure 1: Non-diaphragm thick-walled square steel pipe 1a: Weld bead 1b: Tapered surface 2: Square steel pipe column 3: Steel beam (steel beam)
31: Upper flange 32: Lower flange 33: Web 34: Stiffening rib 4: Brace
5: Gusset plate

The non-diaphragm brace structure according to the first invention is a brace structure in which a horizontal force is borne by providing diagonal braces in addition to a frame of a rigid frame structure in which square steel pipe columns and steel beams are rigidly connected. The joints between the square steel pipe column and the beam are all non-diaphragm thick-wall square steel pipes made of square steel pipes with a hollow cross section that are thicker than other parts of the square steel pipe column, and the non-diaphragm thick-wall The square steel pipe has the same cross-sectional shape both at the joint where the brace is connected and at the joint where the brace is not connected, and the width-thickness ratio between the outside diameter D and the wall thickness t of the non-diaphragm thick-walled square steel pipe. D/t is characterized by satisfying the following equation (5) .
D/t<10.90...Formula (5)

The non-diaphragm brace structure according to the second invention is a brace structure in which horizontal force is borne by providing diagonal braces in addition to a frame of a rigid frame structure in which square steel pipe columns and steel beams are rigidly connected. The joints between the square steel pipe column and the beam are all non-diaphragm thick-walled square steel pipes made of square steel pipes with a hollow cross section that are thicker than other parts of the square steel pipe column, and the axial force acting from the beam is The yield bending strength jcMy of the beam end joint of the non-diaphragm thick-walled rectangular steel pipe satisfies the following formula (1) when considering the axial force acting from the beam. The total plastic bending strength jcMp of the beam end joint of the steel pipe satisfies the following formula (2), and the yield bending strength jMy of the beam end joint of the non-diaphragm thick square steel pipe satisfies the following formula (3), The total plastic bending strength jMp of the beam end joint of the non-diaphragm thick-walled square steel pipe satisfies the following formula (4) and is the width-thickness ratio D of the outside diameter D and wall thickness t of the non-diaphragm thick-walled square steel pipe. /t is characterized by satisfying the following equation (5) .
jcMy≧α×bcMy...Formula (1)
jcMp≧β×bcMp...Formula (2)
jMy≧γ×bMy...Formula (3)
jMp≧δ×bMp...Equation (4)
jcMy: Yield bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
jcMp: Total plastic bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
bcMy: Yield bending strength of the beam (considering the axial force acting on the beam)
bcMp: Total plastic bending strength of the beam (considering the axial force acting on the beam)
jMy: Yield bending strength of non-diaphragm beam end joints
jMp: Total plastic bending strength of non-diaphragm beam end joint
bMy: Yield bending strength of beam
bMp: Total plastic bending strength of the beam α: Joint coefficient 1.0 or more β: Joint coefficient 1.0 or more γ: Joint coefficient 1.0 or more δ: Joint coefficient 1.0 or more
D/t<10.90...Formula (5)

In the non-diaphragm brace structure according to a third aspect of the present invention, in the first or second aspect of the present invention, the cross-sectional shape of the non-diaphragm thick-walled rectangular steel pipe has a tapered surface formed on the inner surface such that the cross-sectional shape becomes thicker as it approaches the inner corner. It is characterized by

A non-diaphragm brace structure according to a fourth aspect of the present invention is the non-diaphragm brace structure according to any one of the first to third aspects, wherein the column shear span ratio (cL/2cD) of the square steel pipe column is 2.5 or more, and The length L of the diaphragm thick-walled square steel pipe is 1500 mm or less. Here, cL: length of the square steel pipe column, cD: outer diameter of the square steel pipe column

According to the first to fourth inventions, all the column-beam joints can be made into non-diaphragm joints in the same structural plane of the brace structure economically without over-spec. Therefore, according to the first to fourth inventions, there is no need to judge and use either the non-diaphragm type or the conventional type (through-diaphragm type or inner diaphragm type) each time depending on the connection, which saves design effort. can be converted into Furthermore, according to the first to fourth inventions, it is possible to use a non-diaphragm type for the joints to which braces are not connected, and it becomes easier to apply the non-diaphragm type to inclined beams and stepped beams, which increases the freedom of design. increases.

Claims (5)

In addition to the frame of a rigid-frame structure that rigidly connects square steel pipe columns and steel beams, brace structures are provided with diagonal braces to bear the horizontal force.
The joints between the square steel pipe column and the beam in the same structural plane are all non-diaphragm thick-walled square steel pipes made of square steel pipes with a hollow cross section that are thicker than other parts of the square steel pipe column,
The non-diaphragm brace structure is characterized in that the non-diaphragm thick-walled rectangular steel pipe has the same cross-sectional shape at both the joint portion to which the brace is connected and the joint portion to which the brace is not connected. In addition to the frame of a rigid-frame structure that rigidly connects square steel pipe columns and steel beams, brace structures are provided with diagonal braces to bear the horizontal force.
The joints between the square steel pipe column and the beam in the same structural plane are all non-diaphragm thick-walled square steel pipes made of square steel pipes with a hollow cross section that are thicker than other parts of the square steel pipe column,
When considering the axial force acting from the beam, the yield bending strength jcMy of the beam end joint of the non-diaphragm thick-walled square steel pipe satisfies the following formula (1),
When considering the axial force acting from the beam, the total plastic bending strength jcMp of the beam end joint of the non-diaphragm thick-walled square steel pipe satisfies the following formula (2), and
The yield bending strength jMy of the beam end joint of the non-diaphragm thick-walled square steel pipe satisfies the following formula (3),
A non-diaphragm brace structure characterized in that the total plastic bending strength jMp of the beam end joint of the non-diaphragm thick-walled rectangular steel pipe satisfies the following formula (4).
jcMy≧α×bcMy...Formula (1)
jcMp≧β×bcMp...Formula (2)
jMy≧γ×bMy...Formula (3)
jMp≧δ×bMp...Equation (4)
jcMy: Yield bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
jcMp: Total plastic bending strength of non-diaphragm beam end joint (considering axial force acting from the beam)
bcMy: Yield bending strength of the beam (considering the axial force acting on the beam)
bcMp: Total plastic bending strength of the beam (considering the axial force acting on the beam)
jMy: Yield bending strength of non-diaphragm beam end joints
jMp: Total plastic bending strength of non-diaphragm beam end joint
bMy: Yield bending strength of beam
bMp: Total plastic bending strength of the beam α: Joint coefficient 1.0 or more β: Joint coefficient 1.0 or more γ: Joint coefficient 1.0 or more δ: Joint coefficient 1.0 or more The non-diaphragm brace structure according to claim 1 or 2, wherein a width-thickness ratio D/t between an outer diameter D and a wall thickness t of the non-diaphragm thick-walled rectangular steel pipe satisfies the following formula (5).
D/t<10.90...Formula (5) The non-diaphragm brace structure according to any one of claims 1 to 3, wherein the cross-sectional shape of the non-diaphragm thick-walled rectangular steel pipe is such that a tapered surface is formed on the inner surface so that the thickness becomes thicker toward the inner corner. . The column shear span ratio ( _c L / 2 _c D) of the square steel pipe column is 2.5 or more,
The non-diaphragm brace structure according to any one of claims 1 to 4, wherein the non-diaphragm thick-walled rectangular steel pipe has a length L of 1500 mm or less.
Here, _c L: Length of the square steel pipe column, _c D: Outer diameter of the square steel pipe column

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