JP6801231B2

JP6801231B2 - Beam evaluation method

Info

Publication number: JP6801231B2
Application number: JP2016104172A
Authority: JP
Inventors: 浅井　英克; 英克浅井
Original assignee: Obayashi Corp
Current assignee: Obayashi Corp
Priority date: 2016-05-25
Filing date: 2016-05-25
Publication date: 2020-12-16
Anticipated expiration: 2036-05-25
Also published as: JP2017210785A

Description

本発明は、梁の評価方法に関する。 The present invention relates to a beam evaluation method.

従来、構造物の鉄骨梁に設備配管などのスリーブを通すために、開口が鉄骨梁のウエブに設けられているが、強度上の問題から開口の周囲を補強する必要がある。例えば特許文献１に記載されているように、梁軸方向に対して４５°に斜めな４本の補強斜材によってウエブの開口を取り囲んでこれら補強斜材を正方形状に組み合わせるように、これら補強斜材をウエブに接合し、ウエブの開口により失われるせん断力負担分を補強斜材の軸力で伝達することによって、鉄骨梁を補強することが行われている。 Conventionally, an opening is provided in the web of the steel beam in order to pass a sleeve such as equipment piping through the steel beam of the structure, but it is necessary to reinforce the circumference of the opening due to a problem in strength. For example, as described in Patent Document 1, these reinforcing diagonal members are reinforced so as to surround the opening of the web with four reinforcing diagonal members oblique to the beam axis direction at 45 ° and combine these reinforcing diagonal members in a square shape. Steel beams are reinforced by joining the diagonal members to the web and transmitting the shear force burden lost by the opening of the web with the axial force of the reinforcing diagonal members.

特開２００３−１４７９０１号公報Japanese Unexamined Patent Publication No. 2003-147901

ところが、特許文献１の技術では、せん断力のみを考慮して補強材を設置するので、曲げモーメントに対して補強材の厚さ及び幅を過剰に設計することになってしまい、補強材の材料費が増えてしまう場合がある。或いは、曲げモーメントに対して、補強材の厚さ又は幅が不足する場合がある。
そこで、本発明は、上記事情に鑑みてなされたものであって、鉄骨梁の開口の周囲を補強する補強材の厚さ及び幅を過剰に設計しないようにするとともに、補強材の厚さ又は幅が不足することに伴う開口補強部の耐力不足を防止することを目的とする。 However, in the technique of Patent Document 1, since the reinforcing material is installed in consideration of only the shearing force, the thickness and width of the reinforcing material are excessively designed with respect to the bending moment, and the material of the reinforcing material is used. The cost may increase. Alternatively, the thickness or width of the reinforcing material may be insufficient with respect to the bending moment.
Therefore, the present invention has been made in view of the above circumstances, and the thickness and width of the reinforcing material for reinforcing the periphery of the opening of the steel frame beam should not be excessively designed, and the thickness of the reinforcing material or the thickness of the reinforcing material or The purpose is to prevent insufficient yield strength of the opening reinforcing portion due to insufficient width.

上記課題を解決するために、本発明の梁の評価方法は、梁軸方向に延在する鉛直な縦板部（２１）と、前記縦板部（２１）の上下に設けられた水平な横板部（２２，２３）と、前記縦板部（２１）に形成された開口（２４）とを有した鉄骨梁本体（２）と、前記開口（２４）の上下において前記梁軸方向に延在するように前記縦板部（２１）に接合された曲げ補強部（３１，４１）と、前記開口（２４）の前記梁軸方向両側において前記梁軸方向に対して斜めな方向に延在するように前記縦板部（２１）に接合されたせん断補強部（３２，３３，４２，４３）と、を備える梁（１）を評価する方法において、前記曲げ補強部（３１，４１）と前記せん断補強部（３２，３３，４２，４３）の幅（Ｂ_b，Ｂ_s）及び厚さ（ｔ_b，ｔ_s）を設定する設定工程（Ｓ２）と、前記設定工程において設定した前記曲げ補強部（３１，４１）と前記せん断補強部（３２，３３，４２，４３）の幅（Ｂ_b，Ｂ_s）及び厚さ（ｔ_b，ｔ_s）に基づいて、前記梁（１）の前記開口（２４）の部分の曲げ耐力とせん断耐力との関係（線ＡＢＣ）を定める工程（Ｓ３，Ｓ４）と、前記梁（１）に想定する設計用せん断力（Ｑ_d）と設計用曲げモーメント（Ｍ_d）を定める設定工程（Ｓ１）と、前記設計用せん断力及び前記設計用曲げモーメントを前記関係と比較する比較工程（Ｓ５）と、を備え、前記関係を定める工程は、前記設定工程において設定した前記せん断補強部（３２，３３，４２，４３）の幅（Ｂs）及び厚さ（ｔ_s）に基づいて、前記梁（１）の前記開口（２４）の部分のせん断耐力（Ｑ_c）を計算する第一計算工程（Ｓ３）と、前記設定工程において設定した前記曲げ補強部（３１，４１）の幅（Ｂ_b）及び厚さ（ｔ_b）に基づいて、せん断力が前記梁の前記開口の部分に作用しない場合の前記梁（１）の前記開口（２４）の部分の第一曲げ耐力（Ｍ_c1）を計算するとともに、前記せん断耐力（Ｑ_c）に相当するせん断力が前記梁の開口の部分に作用する場合の前記梁（１）の前記開口（２４）の部分の第二曲げ耐力（Ｍ_c2）を計算する第二計算工程（Ｓ３）と、前記第二曲げ耐力（Ｍ_c2）と前記第一曲げ耐力（Ｍ_c1）の差（Ｍ_c2−Ｍ_c1）を前記せん断耐力（Ｑ_c）で除することで得られた商（（Ｍ_c2−Ｍ_c1）／Ｑ_c）を傾きとし、前記第一曲げ耐力（Ｍ_c1）を切片とした一次関数（線ＡＢ）を定める工程（Ｓ４）と、を有し、前記比較工程（Ｓ５）は、前記設計用せん断力（Ｑ_d）と前記せん断耐力（Ｑ_c）とを比較するとともに、前記設計用せん断力（Ｑ_d）を前記一次関数（線ＡＢ）に当て嵌めることで得られた曲げ耐力（Ｍ_c）と前記設計用曲げモーメント（Ｍ_d）とを比較する工程（Ｓ５）を有することを特徴とする。 In order to solve the above problems, the beam evaluation method of the present invention includes a vertical vertical plate portion (21) extending in the beam axial direction and horizontal horizontal plates provided above and below the vertical plate portion (21). A steel beam body (2) having a plate portion (22, 23) and an opening (24) formed in the vertical plate portion (21), and extending in the beam axial direction above and below the opening (24). Bending reinforcing portions (31, 41) joined to the vertical plate portion (21) so as to exist, and extending in a direction oblique to the beam axial direction on both sides of the opening (24) in the beam axial direction. In a method of evaluating a beam (1) including a shear reinforcing portion (32, 33, 42, 43) joined to the vertical plate portion (21) so as to be provided with the bending reinforcing portion (31, 41). A setting step (S2) for setting the width (B _b , B _s ) and a thickness (t _b , t _s ) of the shear reinforcing portion (32, 33, 42, 43) and the bending set in the setting step. Of the beam (1), based on the width (B _b , B _s ) and thickness (t _b , t _s ) of the reinforcing portion (31, 41) and the shear reinforcing portion (32, 33, 42, 43). Steps (S3, S4) for determining the relationship (line ABC) between the bending strength and shearing strength of the opening (24), and the design shearing force ( _Qd ) and design bending assumed for the beam (1). the moment setting step (S1) defining a (M _d), e Bei the comparing step (S5), the a bending moment for said design for shear force and the design is compared with the relationship, the step of determining the pre-Symbol relationship, based on the width (Bs) and the thickness (t _s) of the shear reinforcement unit, which is set at the setting step (32,33,42,43), the shear of the portion of the opening (24) of the beam (1) Shearing based on the first calculation step (S3) for calculating the strength (Q _c ) and the width (B _b ) and thickness (t _b ) of the bending reinforcement portion (31, 41) set in the setting step. The first bending strength (M _c1 ) of the opening (24) portion of the beam (1) when the force does not act on the opening portion of the beam is calculated and corresponds to the shear strength (Q _c ). The second calculation step (S3) for calculating the second bending force (M _c2 ) of the opening (24) portion of the beam (1) when the shearing force to be applied acts on the opening portion of the beam, and the above. The quotient ((M _c2 -M) obtained by dividing the difference (M _c2- M _c1 ) between the second bending strength (M _c2 ) and the first bending strength (M _c1 ) by the shear strength (Q _c ). _c1 ) / Q _c ) and the first bending strength (M _c1 ) as a section to determine a linear function (line AB), and the comparison step (S5) is the design. Bending proof stress (M) obtained by comparing the shearing force (Q _d ) and the shearing proof stress (Q _c ) and applying the design shearing force (Q _d ) to the linear function (line AB). It is characterized by having a step (S5) of comparing _c ) with the design bending moment (M _d ).

以上の評価方法では、曲げ補強部とせん断補強部の幅及び厚さに基づいて、梁の開口の部分の曲げ耐力とせん断耐力との関係を定めた上で、その関係を設計用せん断力及び設計用曲げモーメントと比較することで、梁を評価する。そのような比較の結果、設計用せん断力及び設計用曲げモーメントがその関係を充足する場合、つまり、設計用せん断力がせん断耐力以下であり、且つ、設計用曲げモーメントが曲げ耐力以下である場合、設定した曲げ補強部とせん断補強部の幅及び厚さが適切であるとして、梁を評価する。つまり、せん断力のみならず、曲げモーメントも考慮して、曲げ補強部とせん断補強部の幅及び厚さを適切に評価することになる。よって、曲げ補強部とせん断補強部の幅及び厚さを過不足なく設計することができる。 In the above evaluation method, the relationship between the bending strength and the shearing strength of the opening portion of the beam is determined based on the width and thickness of the bending reinforcing portion and the shear reinforcing portion, and then the relationship is determined as the design shearing force and the shearing strength. Evaluate the beam by comparing it with the design bending moment. As a result of such comparison, when the design shear force and the design bending moment satisfy the relationship, that is, when the design shear force is less than or equal to the shear strength and the design bending moment is less than or equal to the bending strength. , Evaluate the beam as the width and thickness of the set bending and shearing reinforcements are appropriate. That is, the width and thickness of the bending reinforcing portion and the shear reinforcing portion are appropriately evaluated in consideration of not only the shearing force but also the bending moment. Therefore, the width and thickness of the bending reinforcing portion and the shear reinforcing portion can be designed without excess or deficiency.

本発明によれば、せん断力及び曲げモーメントの両方を考慮して、曲げ補強部とせん断補強部の幅及び厚さを適切に評価することになるので、曲げ補強部とせん断補強部の幅及び厚さを過不足なく設計することができる。そのため、曲げ補強部とせん断補強部の材料費の増大を抑えることができるとともに、梁の開口の部分の耐力が不足することを防止できる。 According to the present invention, the width and thickness of the bending reinforcing portion and the shear reinforcing portion are appropriately evaluated in consideration of both the shearing force and the bending moment. The thickness can be designed without excess or deficiency. Therefore, it is possible to suppress an increase in the material cost of the bending reinforcing portion and the shear reinforcing portion, and it is possible to prevent the bearing capacity of the opening portion of the beam from being insufficient.

図１は、評価・設計される梁の側面図である。FIG. 1 is a side view of the beam to be evaluated and designed. 図２は、II−II断面図である。FIG. 2 is a sectional view taken along line II-II. 図３は、別例の梁の断面図である。FIG. 3 is a cross-sectional view of another example beam. 図４は、更に別例の梁の側面図である。FIG. 4 is a side view of a beam of another example. 図５は、V−V断面図である。FIG. 5 is a VV cross-sectional view. 図６は、梁の評価方法及び設計方法の工程順序を示したフローチャートである。FIG. 6 is a flowchart showing the process sequence of the beam evaluation method and the design method. 図７は、せん断力がせん断補強部に作用した場合に、そのせん断力をせん断補強部の延在方向の軸力で受け持った状態を示す説明図である。FIG. 7 is an explanatory view showing a state in which when a shear force acts on a shear reinforcing portion, the shearing force is taken over by an axial force in the extending direction of the shear reinforcing portion. 図８は、曲げモーメントが曲げ補強部に作用した場合に、その曲げモーメントを曲げ補強部の延在方向の軸力で受け持った状態を示す説明図である。FIG. 8 is an explanatory view showing a state in which when a bending moment acts on the bending reinforcing portion, the bending moment is taken over by the axial force in the extending direction of the bending reinforcing portion. 図９は、梁の評価に利用する比較判定式を線で表したグラフである。FIG. 9 is a graph showing a comparative judgment formula used for beam evaluation as a line. 図１０は、図９のグラフに具体的な数値を当て嵌めて、設計用せん断力がせん断耐力以下であり、設計用曲げモーメントが曲げ耐力以下であることを説明するための図である。FIG. 10 is a diagram for applying specific numerical values to the graph of FIG. 9 to explain that the design shear force is less than or equal to the shear strength and the design bending moment is less than or equal to the bending strength.

以下、図面を参照して、本発明の実施形態について説明する。以下に述べる実施形態には、本発明を実施するために技術的に好ましい種々の限定が付されているが、本発明の範囲を以下の実施形態及び図示例に限定するものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are provided with various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

１．梁について
図１は、評価・設計される梁１の側面図であり、図２は、II−II断面図である。図１及び図２に示す梁１は、評価・設計の際に利用する構造計算モデルである。この梁１は、隣り合う柱の間に概ね水平に架設されるとともにＨ形鋼からなる鉄骨梁本体２と、鉄骨梁本体２のウエブ２１に設けられた円形状の開口２４を囲うように鉄骨梁本体２のウエブ２１に接合された上下一対の鋼製補強材３，４と、を備える。鋼製補強材３，４とウエブ２１の接合は、例えば隅肉溶接等の溶接又はボルト結合によるものである。 1. 1. About the beam FIG. 1 is a side view of the beam 1 to be evaluated and designed, and FIG. 2 is a sectional view taken along line II-II. The beam 1 shown in FIGS. 1 and 2 is a structural calculation model used at the time of evaluation / design. The beam 1 is erected substantially horizontally between adjacent columns and is a steel frame so as to surround a steel beam main body 2 made of H-shaped steel and a circular opening 24 provided in the web 21 of the steel beam main body 2. A pair of upper and lower steel reinforcing members 3 and 4 joined to the web 21 of the beam main body 2 are provided. The joining of the steel reinforcing members 3 and 4 and the web 21 is by welding such as fillet welding or bolt connection.

鉄骨梁本体２は、梁軸方向（梁の長手方向）に帯板状に延びた鉛直なウエブ（縦板部）２１と、梁軸方向に帯板状に延びた上下一対の水平なフランジ（横板部）２２，２３とを有し、梁軸方向に直交する断面形状がＨ形を成している。ウエブ２１には、開口２４が貫通するよう形成されている。 The steel beam main body 2 has a vertical web (vertical plate portion) 21 extending in a strip shape in the beam axial direction (longitudinal direction of the beam) and a pair of upper and lower horizontal flanges extending in a strip shape in the beam axial direction. Horizontal plate portions) 22 and 23, and the cross-sectional shape orthogonal to the beam axis direction is H-shaped. The web 21 is formed so as to penetrate the opening 24.

鋼製補強材３は、開口２４の上側において梁軸方向に延在した曲げ補強部３１と、開口２４の上半分の梁軸方向両側において梁軸方向に対して斜めの方向に延在する帯状のせん断補強部３２，３３とを有する。曲げ補強部３１とせん断補強部３２，３３は一体形成された状態にある。 The steel reinforcing member 3 has a bending reinforcing portion 31 extending in the beam axial direction on the upper side of the opening 24 and a strip-shaped extending in a diagonal direction with respect to the beam axial direction on both sides of the upper half of the opening 24 in the beam axial direction. It has shear reinforcing portions 32 and 33 of the above. The bending reinforcing portion 31 and the shear reinforcing portions 32 and 33 are integrally formed.

曲げ補強部３１は等脚台形板状に形成され、曲げ補強部３１の上底３１ａ及び下底３１ｂが梁軸方向に対して平行であり、上底３１ａが下底３１ｂよりも短く、一対の脚３１ｃ，３１ｄの間隔は下に向かって漸増する。上底３１ａと下底３１ｂの中点を通る直線は鉛直方向に延在するとともに、開口２４の中心点を通る。ここで、曲げ補強部３１の延在方向は、互いに平行な上底３１ａ及び下底３１ｂが延びる方向を指すものとする。 The bending reinforcement portion 31 is formed in an isosceles trapezoidal plate shape, the upper base 31a and the lower bottom 31b of the bending reinforcement portion 31 are parallel to the beam axial direction, the upper base 31a is shorter than the lower base 31b, and a pair. The distance between the legs 31c and 31d gradually increases downward. The straight line passing through the midpoints of the upper base 31a and the lower base 31b extends in the vertical direction and passes through the center point of the opening 24. Here, the extending direction of the bending reinforcing portion 31 is defined as the direction in which the upper base 31a and the lower base 31b parallel to each other extend.

せん断補強部３２，３３は、これらの間に開口２４の上半分が位置するように、曲げ補強部３１の下底３１ｂの両側部から下広がりに延出する。せん断補強部３２，３３は帯板状に形成され、平行二辺のうち一方の長辺３２ａ，３３ａが曲げ補強部３１の脚３１ｃ，３１ｄと一直線状になっており、他方の長辺３２ｂ，３３ｂと曲げ補強部３１の下底３１ｂの成す角は鈍角であり、下側の短辺３２ｃ，３３ｃは曲げ補強部３１の下底３１ｂに対して平行である。ここで、せん断補強部３２の延在方向は互いに平行な長辺３２ａ，３２ｂを指すものとし、せん断補強部３３の延在方向についても同様である。 The shear reinforcing portions 32 and 33 extend downward from both sides of the lower base 31b of the bending reinforcing portion 31 so that the upper half of the opening 24 is located between them. The shear reinforcing portions 32 and 33 are formed in a strip shape, and one of the two parallel sides, 32a and 33a, is linear with the legs 31c and 31d of the bending reinforcing portion 31, and the other long side 32b, The angle formed by 33b and the lower bottom 31b of the bending reinforcing portion 31 is an obtuse angle, and the lower short sides 32c and 33c are parallel to the lower bottom 31b of the bending reinforcing portion 31. Here, the extending direction of the shear reinforcing portion 32 refers to the long sides 32a and 32b parallel to each other, and the same applies to the extending direction of the shear reinforcing portion 33.

鋼製補強材３は、開口２４の中心を通る鉛直線に関して、梁軸方向に対称な形状である。そのため、せん断補強部３２の幅（長辺３２ａと長辺３２ｂの間隔）とせん断補強部３３の幅（長辺３２ａと長辺３２ｂの間隔）は互いに等しい上、梁軸方向に対するせん断補強部３２の延在方向の成す角は梁軸方向に対するせん断補強部３３の延在方向の成す角に等しい。 The steel reinforcing member 3 has a shape symmetrical with respect to the vertical straight line passing through the center of the opening 24 in the beam axis direction. Therefore, the width of the shear reinforcing portion 32 (distance between the long side 32a and the long side 32b) and the width of the shear reinforcing portion 33 (distance between the long side 32a and the long side 32b) are equal to each other, and the shear reinforcing portion 32 in the beam axial direction. The angle formed in the extending direction of is equal to the angle formed in the extending direction of the shear reinforcing portion 33 with respect to the beam axis direction.

鋼製補強材４は、開口２４の下側において梁軸方向に延在した曲げ補強部４１と、開口２４の下半分の梁軸方向両側において梁軸方向に対して斜めの方向に延在する帯状のせん断補強部４２，４３とを有する。下側の鋼製補強材４と上側の鋼製補強材３は開口２４の中心を通る水平線に関して互いに対称であるので、下側の鋼製補強材４の詳細な説明を省略する。なお、せん断補強部４３の延在方向とせん断補強部３２の延在方向は互いに平行であり、せん断補強部３３の延在方向とせん断補強部４２の延在方向は互いに平行である。 The steel reinforcing member 4 extends in a bending reinforcing portion 41 extending in the beam axial direction under the opening 24 and in a direction oblique to the beam axial direction on both sides of the lower half of the opening 24 in the beam axial direction. It has strip-shaped shear reinforcing portions 42 and 43. Since the lower steel reinforcing material 4 and the upper steel reinforcing material 3 are symmetrical with respect to the horizontal line passing through the center of the opening 24, detailed description of the lower steel reinforcing material 4 will be omitted. The extending direction of the shear reinforcing portion 43 and the extending direction of the shear reinforcing portion 32 are parallel to each other, and the extending direction of the shear reinforcing portion 33 and the extending direction of the shear reinforcing portion 42 are parallel to each other.

図１及び図２に示す例では、鋼製補強材３，４がウエブ２１の片面に接合されている。それに対して、図３に示す例では、鋼製補強材３，４がウエブ２１の両面に接合されている。この場合、図３の矢印ａの方向に向かって平行投影した場合、一方の鋼製補強材３の外縁と他方の鋼製補強材３の外縁が重なる。鋼製補強材４についても同様である。 In the examples shown in FIGS. 1 and 2, the steel reinforcing members 3 and 4 are joined to one side of the web 21. On the other hand, in the example shown in FIG. 3, the steel reinforcing members 3 and 4 are joined to both sides of the web 21. In this case, when parallel projection is performed in the direction of the arrow a in FIG. 3, the outer edge of one steel reinforcing material 3 and the outer edge of the other steel reinforcing material 3 overlap. The same applies to the steel reinforcing material 4.

図１及び図２に示す例では、曲げ補強部３１とせん断補強部３２，３３が一体形成された状態にあり、曲げ補強部４１とせん断補強部４２，４３が一体形成された状態にある。それに対して、図４及び図５に示す例では、曲げ補強部３１とせん断補強部３２，３３が別体であり、曲げ補強部４１とせん断補強部４２，４３が別体であり、曲げ補強部３１，４１がウエブ２１の一方の面に接合され、せん断補強部３２，３３，４２，４３がウエブ２１の他方の面に接合されている。ここで、曲げ補強部３１，４１は、梁軸方向に平行な長辺及び梁成方向に平行な短辺を有する長方形板状であり、曲げ補強部３１，４１の延在方向は、互いに平行な長辺が延びる方向を指す。また、せん断補強部３２，３３，４２，４３は、梁軸方向に対して斜めの長辺を有する直方体板状であり、せん断補強部３２，３３，４２，４３の延在方向は、互いに平行な長辺が延びる方向を指す。 In the examples shown in FIGS. 1 and 2, the bending reinforcing portion 31 and the shear reinforcing portions 32 and 33 are integrally formed, and the bending reinforcing portion 41 and the shear reinforcing portions 42 and 43 are integrally formed. On the other hand, in the examples shown in FIGS. 4 and 5, the bending reinforcing portion 31 and the shear reinforcing portions 32 and 33 are separate bodies, and the bending reinforcing portion 41 and the shear reinforcing portions 42 and 43 are separate bodies. The portions 31, 41 are joined to one surface of the web 21, and the shear reinforcing portions 32, 33, 42, 43 are joined to the other surface of the web 21. Here, the bending reinforcing portions 31 and 41 have a rectangular plate shape having a long side parallel to the beam axis direction and a short side parallel to the beam forming direction, and the extending directions of the bending reinforcing portions 31 and 41 are parallel to each other. Refers to the direction in which the long side extends. Further, the shear reinforcing portions 32, 33, 42, 43 have a rectangular parallelepiped shape having long sides oblique to the beam axis direction, and the extending directions of the shear reinforcing portions 32, 33, 42, 43 are parallel to each other. Refers to the direction in which the long side extends.

図１、図３、図４の何れの例でも、鉄骨梁本体２のウエブ２１に開口２４が形成されているので、以上のような梁１を設計する際に想定し得る設計用せん断力Ｑ_d [kN]及び設計用曲げモーメントＭ_d [kN・m]が梁１の開口２４の部分に作用した場合、設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dを鉄骨梁本体２のみでは負担することができない場合がる。そのため、鉄骨梁本体２の開口２４の部分を補強するべく、以上のように補強部３１，３２，３３，４１、４２，４３が鉄骨梁本体２に設けられ、設計用曲げモーメントＭ_dを鉄骨梁本体２及び曲げ補強部３１，４１で負担し、設計用せん断力Ｑ_dを鉄骨梁本体２及びせん断補強部３２，３３，４２，４３で負担する。それゆえ、梁１を設計する際に、補強部３１，３２，３３，４１，４２，４３による鉄骨梁本体２の補強、つまり梁１の強度が適切であるか否かを以下の方法によって評価して、梁１の各部の寸法及び降伏点（表１参照）を数値として決定する。なお、せん断力及び曲げモーメントが梁１の開口２４の部分に作用するとは、そのせん断力及び曲げモーメントが開口２４の三次元的中心点（三次元的中心点とは、側面視における開口２４の中心点を通って梁軸方向に直交する鉛直断面における開口２４の中心点のことをいう。以下、同じ。）に作用すると仮定した場合に、そのせん断力及び曲げモーメントを開口２４の周辺部が負担することをいう。従って、梁１の開口２４の部分のせん断耐力とは、そのせん断耐力を超えたせん断力が開口２４の三次元的中心点に作用したと仮定した場合に、そのせん断力を開口２４の周辺部が負担すると、梁１の開口２４の周辺部が破壊するこという。また、梁１の開口２４の部分の曲げ耐力とは、その曲げ耐力を超えた曲げモーメントが開口２４の三次元的中心点に作用したと仮定した場合に、その曲げモーメントを開口２４の周辺部が負担すると、梁１の開口２４の周辺部が破壊するこという。 In any of the examples of FIGS. 1, 3 and 4, since the opening 24 is formed in the web 21 of the steel beam main body 2, the design shear force Q that can be assumed when designing the beam 1 as described above _{When d} [kN] and the design bending moment M _d [kN · m] act on the opening 24 of the beam 1, the design shear force Q _d and the design bending moment M _d are borne by the steel beam body 2 alone. You may not be able to. Therefore, in order to reinforce the opening 24 portion of the steel beam main body 2, the reinforcing portions 31, 32, 33, 41, 42, 43 are provided in the steel beam main body 2 as described above, and the design bending moment M _{d is set} to the steel frame. borne by the beam body 2 and the bending reinforcement portion 31 and 41, bear the design for shear force Q _d in steel beams body 2 and shear reinforcement unit 32,33,42,43. Therefore, when designing the beam 1, the reinforcement of the steel beam body 2 by the reinforcing portions 31, 32, 33, 41, 42, 43, that is, whether or not the strength of the beam 1 is appropriate is evaluated by the following method. Then, the dimensions and yield points (see Table 1) of each part of the beam 1 are determined as numerical values. It should be noted that the shearing force and bending moment acting on the portion of the opening 24 of the beam 1 means that the shearing force and bending moment are the three-dimensional center points of the opening 24 (the three-dimensional center point is the opening 24 in the side view). The center point of the opening 24 in the vertical cross section that passes through the center point and is orthogonal to the beam axis direction. The same shall apply hereinafter), and the shear force and bending moment are applied to the peripheral portion of the opening 24. It means to bear. Therefore, the shear strength of the portion of the opening 24 of the beam 1 is the shear strength of the peripheral portion of the opening 24, assuming that the shear strength exceeding the shear strength acts on the three-dimensional center point of the opening 24. Is said to destroy the peripheral portion of the opening 24 of the beam 1. Further, the bending strength of the portion of the opening 24 of the beam 1 means that, assuming that a bending moment exceeding the bending strength acts on the three-dimensional center point of the opening 24, the bending moment is applied to the peripheral portion of the opening 24. Is said to destroy the peripheral portion of the opening 24 of the beam 1.

２．梁の評価及び設計
以下、図６を参照して、梁１の評価方法及び設計方法について詳細に説明する。ここで、梁１の各部の寸法及び降伏点を表す記号は表１及び図１〜図５のように定義する。 2. 2. Evaluation and Design of Beams Hereinafter, the evaluation method and design method of the beam 1 will be described in detail with reference to FIG. Here, symbols representing the dimensions and yield points of each part of the beam 1 are defined as shown in Table 1 and FIGS. 1 to 5.

ここで、用いる鉄骨梁本体２が予め決まっているものとするので、以下のように梁１の評価及び設計をする際には、鉄骨梁本体２の梁成Ｄ，フランジ２２，２３の幅Ｂ，ウエブ２１の厚さｔ_w，フランジ２２，２３の厚さｔ_f，開口２４の直径φ，フランジ２２，２３の降伏点σ_yf及びウエブ２１の降伏点σ_ywは数値（設計値）として予め設定されている。また、用いる補強部３１，３２，３３，４１，４２，４３の位置及び材料が予め決まっているものとするので、距離Ｈ_b，曲げ補強部３１，４１の降伏点σ_yb，せん断補強部３２，３３，４２，４３の降伏点σ_ys及び成す角θは数値（設計値）として予め設定されている。従って、以下に説明する梁１の評価とは、想定する設計用せん断力Ｑ_d 及び設計用曲げモーメントＭ_dが梁１の開口２４の部分に作用した場合に、梁１が設計用せん断力Ｑ_d 及び設計用曲げモーメントＭ_dに耐え得るのに曲げ補強部３１，４１の幅Ｂ_b，曲げ補強部３１，４１の厚さｔ_b，せん断補強部３２，３３，４２，４３の幅Ｂ_s及びせん断補強部３２，３３，４２，４３の厚さｔ_sが適切であるか否かを評価することである。また、以下に説明する梁１の設計とは、想定する設計用せん断力Ｑ_d 及び設計用曲げモーメントＭ_dが梁１の開口２４の部分に作用した場合に、梁１が設計用せん断力Ｑ_d 及び設計用曲げモーメントＭ_dに耐え得るように、曲げ補強部３１，４１の幅Ｂ_b，曲げ補強部３１，４１の厚さｔ_b，せん断補強部３２，３３，４２，４３の幅Ｂ_s及びせん断補強部３２，３３，４２，４３の厚さｔ_sの数値を決定することである。 Here, since it is assumed that the steel beam main body 2 to be used is determined in advance, when evaluating and designing the beam 1 as described below, the beam formation D of the steel beam main body 2 and the widths B of the flanges 22 and 23 are B. , the thickness t _w of the web 21, the thickness t _f of the flange 22, the diameter of the aperture 24 phi, the yield point sigma _yw yield point sigma _yf and webs 21 of the flange 22, 23 in advance as numeric (design value) It is set. Further, since the positions and materials of the reinforcing portions 31, 32, 33, 41, ₄₂ , ₄₃ to be used are determined in advance, the distance H _b , the yield point σ _yb of the bending reinforcing portions 31, 41, and the shear reinforcing portion 32 , 33, 42, 43 yield points σ _ys and the angle θ formed are preset as numerical values (design values). Therefore, the evaluation of the beam 1 described below means that the beam 1 has a design shear force Q when the assumed design shear force Q _d and the design bending moment M _d act on the opening 24 of the beam 1. Width B _b of bending reinforcements 31, 41, thickness t _b of bending reinforcements 31, 41, width B _{s of} shear reinforcements 32, 33, 42, 43 to withstand _d and design bending moment M _d And it is to evaluate whether or not the thickness t _s of the shear reinforcing part 32, 33, 42, 43 is appropriate. Further, in the design of the beam 1 described below, when the assumed design shear force Q _d and the design bending moment M _d act on the opening 24 portion of the beam 1, the beam 1 has the design shear force Q. The width B _{b of} the bending reinforcing portions 31 and 41, the thickness t _b of the bending reinforcing portions 31 and 41, and the width B of the shear reinforcing portions 32, 33, 42, 43 so as to withstand _d and the design bending moment M _d. It is to determine the numerical value of the thickness t _s of _s and the shear reinforcing portions 32, 33, 42, 43.

なお、図３に示すように、ウエブ２１の両面に鋼製補強材３が接合されている場合には、両面の曲げ補強部３１の厚さの和をｔ_bとする。曲げ補強部４１及びせん断補強部３２，３３，４２，４３についても同様である。 As shown in FIG. 3, when the steel reinforcing members 3 are joined to both sides of the web 21, the sum of the thicknesses of the bending reinforcing portions 31 on both sides is t _b . The same applies to the bending reinforcing portion 41 and the shear reinforcing portions 32, 33, 42, 43.

（Ａ）ステップＳ１：設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dの設定
梁１に関する構造計算書等に基づいて、梁１の開口２４の部分に作用し得る設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dの数値を設定する。ここで、構造計算書には、梁１が設けられる建物等の構造物の仕様（高さ、重量、梁１の階数、梁１の位置、梁１のスパン等）が記載されているとともに、構造物の各部（梁１を含む）に作用する設計用荷重が記載されているので、設計用荷重から梁１の開口２４の部分に作用し得る設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dの数値を解析により算出して、設定することができる。 (A) Step S1: Setting of design shear force Q _d and design bending moment M _d Design shear force Q _d and that can act on the opening 24 of the beam 1 based on the structural calculation sheet related to the beam 1. Set the value of the design bending moment M _d . Here, the structural calculation sheet describes the specifications (height, weight, number of floors of the beam 1, the position of the beam 1, the span of the beam 1, etc.) of the structure such as the building where the beam 1 is provided. Since the design load acting on each part of the structure (including the beam 1) is described, the design shear force Q _d and the design bending moment M that can act on the opening 24 portion of the beam 1 from the design load are described. The numerical value of _d can be calculated and set by analysis.

（Ｂ）ステップＳ２：梁１の各部の寸法及び降伏点の設定
梁１の各部の寸法（表１のＤ，Ｂ，ｔ_w，ｔ_f，φ，Ｂ_b，ｔ_b，Ｈ_b，Ｂ_s，ｔ_s，θ）及び降伏点（表１のσ_yf，σ_yw，σ_yb，σ_ys）の数値を設定する。なお、上述したように、Ｄ，Ｂ，ｔ_w，ｔ_f，φ，Ｈ_b，σ_yf，σ_yw，σ_yb，σ_ys及びθ_sは予め決められた数値であるが、Ｂ_b，ｔ_b，Ｂ_s及びｔ_sは仮に設定する数値である。 (B) Step S2: Setting the dimensions and yield point of each part of the beam 1 Dimensions of each part of the beam 1 (D, B, t _w , t _f , φ, B _b , t _b , H _b , B _{s in} Table 1) , T _s , θ) and the yield point (σ _yf , σ _yw , σ _yb , σ _{ys in} Table 1). As described _{above, D, B, t w,} t f, φ, H b, σ yf, σ yw, σ yb, σ ys and theta _s but is a numerical value predetermined, B _b, t _b , B _s and t _s are tentatively set numerical values.

（Ｃ）ステップＳ３：せん断耐力Ｑ_c及び曲げ耐力Ｍ_c1，Ｍ_c2の計算
以下に説明する通り、梁１の各部の寸法（表１のＤ，Ｂ，ｔ_w，ｔ_f，φ，Ｂ_b，ｔ_b，Ｈ_b，Ｂ_s，ｔ_s，θ）及び降伏点（表１のσ_yf，σ_yw，σ_yb，σ_ys）に基づいてせん断耐力Ｑ_c [kN]、第一曲げ耐力Ｍ_c1 [kN・m]，第二曲げ耐力Ｍ_c2 [kN・m]の数値を計算する。ここで、第一曲げ耐力Ｍ_c1はせん断力が梁１の開口２４の部分に作用しない場合の開口２４の部分の曲げ耐力であり、第二曲げ耐力Ｍ_c2はせん断耐力Ｑ_cに相当するせん断力が梁１の開口２４の部分に作用する場合の開口２４の部分の曲げ耐力である。 (C) Step S3: Calculation of shear strength Q _c and bending strength M _c1 and M _{c2 As} explained below, the dimensions of each part of the beam 1 (D, B, t _w , t _f , φ, B _{b in} Table 1 _). , T _b , H _b , B _s , t _s , θ) and yield _strength (σ _yf , σ _yw , σ _yb , σ _{ys in} Table 1), shear strength Q _c [kN], first bending strength M Calculate the values of _c1 [kN ・ m] and second bending strength M _c2 [kN ・ m]. Here, the first bending proof stress M _c1 is the bending proof stress of the opening 24 portion when the shearing force does not act on the opening 24 portion of the beam 1, and the second bending proof stress M _{c 2} is the shear corresponding to the shear strength Q _c. This is the bending strength of the opening 24 when a force acts on the opening 24 of the beam 1.

・せん断耐力Ｑ_cについて（図７参照）
次式（１）により、開口２４を有する鉄骨梁本体２のせん断耐力Ｑ_cg [kN]を計算する。

・ Shear strength Q _c (see Fig. 7)
The shear strength Q _cg [kN] of the steel beam body 2 having the opening 24 is calculated by the following equation (1).

図７に示すようにせん断力がせん断補強部３２，３３，４２，４３に作用した場合に、そのせん断力をせん断補強部３２，３３，４２，４３の延在方向の軸力で受け持つとすると、せん断補強部３２，３３，４２，４３の延在方向における軸耐力Ｐ_ys [kN]がＢ_s×ｔ_s×σ_ysであるので、次式（２）によりせん断補強部３２，３３，４２，４３のせん断耐力Ｑ_cr [kN]を計算する。

As shown in FIG. 7, when a shear force acts on the

shear reinforcing portions

32, 33, 42, 43, it is assumed that the shear force is taken over by the axial force in the extending direction of the

shear reinforcing portions

32, 33, 42, 43. Since the axial force force P _ys [kN] of the

shear reinforcing portions

32, 33, 42, 43 in the extending direction is B _s × t _s × σ _ys , the

shear reinforcing portions

32, 33, 42 according to the following equation (2). , 43 Shear strength Q _cr [kN] is calculated.

そして、鉄骨梁本体２のせん断耐力Ｑ_cgとせん断補強部３２，３３，４２，４３のせん断耐力Ｑ_crの和を求める。その和は、梁１の開口２４の部分のせん断耐力Ｑ_cである。

Then, the sum of the shear strength Q _cg of the steel beam body 2 and the shear strength Q _cr of the

shear reinforcing portions

32, 33, 42, 43 is obtained. The sum is a shear strength Q _c of the portion of the opening 24 of the beam 1.

・曲げ耐力Ｍ_c1，Ｍ_c2について（図８参照）
次式（４）により、開口２４を有する鉄骨梁本体２の曲げ耐力Ｍ_c1g [kN・m]を計算する。

ここで、

である。・ Bending strength M _c1 and M _c2 (see Fig. 8)
The bending strength M _c1g [kN · m] of the steel beam body 2 having the opening 24 is calculated by the following equation (4).

here,

Is.

図８に示すように曲げモーメントが曲げ補強部３１，４１に作用した場合に、その曲げモーメントを曲げ補強部３１，４１の延在方向の軸力で受け持つとすると、曲げ補強部３１，４１の延在方向における軸耐力Ｐ_yb [kN]がＢ_b×ｔ_b×σ_ybであるので、次式（５）により、曲げ補強部３１，４１の曲げ耐力Ｍ_c1r [kN・m]を計算する。

ここで、

である。 As shown in FIG. 8, when a bending moment acts on the

bending reinforcing portions

31 and 41, assuming that the bending moment is handled by the axial force in the extending direction of the

bending reinforcing portions

31 and 41, the

bending reinforcing portions

31 and 41 Since the axial proof stress P _yb [kN] in the extending direction is B _b × t _b × σ _yb , the bending proof stress M _c1r [kN · m] of the

bending reinforcing portions

31 and 41 is calculated by the following equation (5). ..

here,

Is.

そして、鉄骨梁本体２の曲げ耐力Ｍ_c1gと曲げ補強部３１，４１の曲げ耐力Ｍ_c1rの和を求める。その和は、せん断力が梁１の開口２４の部分に作用しない場合の梁１の開口２４の部分の第一曲げ耐力Ｍ_c1である。

Then, the sum of the bending strength M _c1g of the steel beam body 2 and the bending strength M _c1r of the

bending reinforcing portions

31 and 41 is obtained. The sum is the first bending strength M _c1 of the opening 24 portion of the beam 1 when the shearing force does not act on the opening 24 portion of the beam 1.

一方、曲げ耐力Ｍ_c1からウエブ２１及び曲げ補強部３１，４１の寄与分を控除すれば、せん断耐力Ｑ_cに相当するせん断力が梁１の開口２４の部分に作用する場合の第二曲げ耐力Ｍ_c2 [kN・m]を求められるので、次式（７）により第二曲げ耐力Ｍ_c2を計算する。

On the other hand, if the contributions of the web 21 and the

bending reinforcing portions

31 and 41 are subtracted from the bending strength M _c1 , the second bending strength when the shear force corresponding to the shear strength Q _c acts on the opening 24 of the beam 1. Since M _c2 [kN · m] can be obtained, the second bending strength M _c2 is calculated by the following equation (7).

（Ｄ）ステップＳ４：比較判定式の設定
上記ステップＳ３において計算した梁１の開口２４の部分のせん断耐力Ｑ_cから、せん断力Ｑ[kN]に関する比較判定式を次式（８）のように設定する。

(D) Step S4: Setting of comparison judgment formula From the shear strength Q _c of the opening 24 portion of the beam 1 calculated in step S3 above, the comparison judgment formula regarding the shear force Q [kN] is as shown in the following formula (8). Set.

この比較判定式（８）は、梁１の開口２４の部分に作用するせん断力Ｑがせん断耐力Ｑ_c以下であれば、梁１がそのせん断力Ｑに耐え得ることを表す。 This comparative determination formula (8) indicates that if the shear force Q acting on the portion of the opening 24 of the beam 1 is equal to or less than the shear strength Q _c , the beam 1 can withstand the shear strength Q.

せん断耐力Ｑ_c及び曲げ耐力Ｍ_c1，Ｍ_c2とから、曲げモーメントＭ [kN・m]に関する比較判定式を次式（９）のように設定する。

From the shear strength Q _c and the bending strengths M _c1 and M _c2 , the comparative judgment formula for the bending moment M [kN · m] is set as in the following formula (9).

この比較判定式（９）において、変数Ｍ_cはせん断力Ｑが梁１の開口２４の部分に作用する場合の梁１の開口２４の部分の曲げ耐力を表し、変数Ｍ_cはせん断力Ｑを独立変数としたせん断力Ｑの一次関数である。比較判定式（９）は、梁１の開口２４の部分に作用するせん断力Ｑと、そのせん断力Ｑが梁１の開口２４の部分に作用した場合の梁１の開口２４の部分の曲げ耐力Ｍ_cとの関係を表したものである。つまり、この比較判定式（９）は、せん断力Ｑが梁１の開口２４の部分に作用した場合に、梁１の開口２４の部分に作用する曲げモーメントＭがそのせん断力Ｑから定まる曲げ耐力Ｍ_c以下であれば、梁１がその曲げモーメントＭに耐え得ることを表す。 In this comparative determination formula (9), the variable M _c represents the bending strength of the opening 24 portion of the beam 1 when the shear force Q acts on the opening 24 portion of the beam 1, and the variable M _c represents the shear force Q. It is a linear function of the shear force Q as an independent variable. In the comparative judgment formula (9), the shearing force Q acting on the opening 24 portion of the beam 1 and the bending strength of the opening 24 portion of the beam 1 when the shearing force Q acts on the opening 24 portion of the beam 1. It shows the relationship with M _c . That is, in this comparative determination formula (9), when the shearing force Q acts on the opening 24 of the beam 1, the bending moment M acting on the opening 24 of the beam 1 is determined from the shearing force Q. If it is M _c or less, it means that the beam 1 can withstand the bending moment M.

ここで、図９に示すように、変数としてのせん断力Ｑを横軸により表し、変数としての曲げモーメントＭを縦軸により表す直交座標系のグラフに点Ａ（０，Ｍ_c1）、点Ｂ（Ｑ_c，Ｍ_c2）及び点Ｃ（Ｑ_c，０）をプロットすると、線ＢＣの左側の領域が比較判定式（８）を表し、線ＡＢの下側の領域が比較判定式（９）を表す。線ＡＢＣは、せん断耐力Ｑ_c及び曲げ耐力Ｍ_c1，Ｍ_c2に基づいて定められた曲げせん断耐力曲線であり、その曲げせん断耐力曲線は、梁１の開口２４の部分の曲げ耐力とのせん断耐力との関係を表す。
線ＡＢが右肩下がりとなっているのは、つまり式（９）の一次関数の傾きが負となっているのは、梁１の開口２４の部分に作用するせん断力Ｑが増加するにつれて、梁１の開口２４の部分２４の曲げ耐力Ｍ_cが減少するようしたものである。即ち、数値Ｑのせん断力が梁１の開口２４の部分に作用すると、梁１の開口２４の部分がそのせん断力に耐えうるように数値Ｑのせん断耐力を必要とするが、梁１の開口２４の部分の全体としての耐力がせん断耐力として用いられる分だけ、梁１の開口２４の部分の全体としての耐力のうち曲げ耐力として用いられる分が減少するので、線ＡＢ及び式（９）のようにせん断力Ｑが増加するにつれて曲げ耐力Ｍ_cが減少することになる。 Here, as shown in FIG. 9, points A (0, _Mc1 ) and B are shown in a graph of a Cartesian coordinate system in which the shear force Q as a variable is represented by the horizontal axis and the bending moment M as a variable is represented by the vertical axis. When (Q _c , M _c2 ) and the point C (Q _c , 0) are plotted, the area on the left side of the line BC represents the comparison judgment formula (8), and the area below the line AB is the comparison judgment formula (9). Represents. The line ABC is a bending shear strength curve determined based on the shear strength Q _c and the bending strengths M _c1 and M _c2 , and the bending shear strength curve is the shear strength with the bending strength of the opening 24 of the beam 1. Represents the relationship with.
The reason why the line AB is downward-sloping, that is, the slope of the linear function of Eq. (9) is negative, is that as the shear force Q acting on the opening 24 of the beam 1 increases, The bending strength M _c of the portion 24 of the opening 24 of the beam 1 is reduced. That is, when the shearing force of the numerical value Q acts on the portion of the opening 24 of the beam 1, the shearing strength of the numerical value Q is required so that the portion of the opening 24 of the beam 1 can withstand the shearing force, but the opening of the beam 1 Since the proof stress of the 24 portion as a whole is used as the shear strength, the portion of the proof stress of the opening 24 portion of the beam 1 used as the bending proof stress is reduced, so that the line AB and the formula (9) As the shear force Q increases, the bending proof stress M _c decreases.

（Ｅ）ステップＳ５：比較・判定
比較判定式（８）のせん断力Ｑに設計用せん断力Ｑ_dを当て嵌めて、比較判定式（８）に従って設計用せん断力Ｑ_dとせん断耐力Ｑ_cとを比較することによって、比較判定式（８）を充足するか否かを判定する。更に、比較判定式（９）のせん断力Ｑと曲げモーメントＭにそれぞれ設計用せん断力Ｑ_dと設計用曲げモーメントＭ_dを当て嵌め、設計用せん断力Ｑ_dを比較判定式（９）に当て嵌めることによって得られた曲げ耐力Ｍ_cを求めて、比較判定式（９）に従って曲げ耐力Ｍ_cと設計用曲げモーメントＭ_dとを比較することによって、比較判定式（９）を充足するか否かを判定する。 (E) Step S5: Comparison / judgment The design shear force Q _d is applied to the shear force Q of the comparison judgment formula (8), and the design shear force Q _d and the shear strength Q _c are combined according to the comparison judgment formula (8). It is determined whether or not the comparison determination formula (8) is satisfied by comparing. Furthermore, comparison judgment formula (9) of the shear force Q and bending each designed for shear force moment M Q _d and fit the design for the bending moment M _d, applying a design for shear force Q _d to comparative judgment formula (9) Whether or not the comparative judgment formula (9) is satisfied by obtaining the bending strength M _c obtained by fitting and comparing the bending strength M _c with the design bending moment M _d according to the comparative judgment formula (9). Is determined.

つまり、線ＡＢ，線ＢＣが表された図９のグラフに点Ｄ（Ｑ_d，Ｍ_d）をプロットし（点Ｄは点Ｄ1〜点Ｄ4の何れか）、点Ｄが曲げせん断耐力曲線ＡＢＣの内側に存在するか否かを判定する。具体的には、線ＢＣの左側の領域に存在するか否かを判定するが、点Ｄが点Ｄ1又は点Ｄ3のように線ＢＣの左側の領域に存在すれば、比較判定式（８）を充足し、点Ｄが点Ｄ2又は点Ｄ4のように線ＢＣの右側の領域に存在すれば、比較判定式（８）を充足しない。また、点Ｄが線ＡＢの下側の領域に存在するか否かを判定するが、点Ｄが点Ｄ1又は点Ｄ2のように線ＡＢの下側の領域に存在すれば、比較判定式（９）を充足し、点Ｄが点Ｄ3又は点Ｄ4のように線ＢＣの右側の領域に存在すれば、比較判定式（９）を充足しない。 That is, the points D (Q _d , M _d ) are plotted on the graph of FIG. 9 in which the lines AB and BC are represented (point D is any of points D1 to D4), and point D is the bending shear strength curve ABC. Determine if it exists inside. Specifically, it is determined whether or not it exists in the region on the left side of the line BC, but if the point D exists in the region on the left side of the line BC like the point D1 or the point D3, the comparison determination formula (8) If the point D exists in the region on the right side of the line BC like the point D2 or the point D4, the comparison determination formula (8) is not satisfied. Further, it is determined whether or not the point D exists in the region below the line AB, but if the point D exists in the region below the line AB like the point D1 or the point D2, the comparison determination formula ( If 9) is satisfied and the point D exists in the region on the right side of the line BC like the point D3 or the point D4, the comparison determination formula (9) is not satisfied.

（Ｆ）ステップＳ６：曲げ補強部，せん断補強部の幅及び厚さの設定値の変更
図９に示す点Ｄ2，Ｄ4のように、ステップＳ５の比較判定工程において比較判定式（８）を充足しなければ、せん断補強部３２，３３，４２，４３の幅Ｂ_s及び厚さｔ_sが設定された梁１は設計用せん断力Ｑ_dに耐えることができず、設定された幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sが不適切である。また、図９に示す点Ｄ3，Ｄ4のように、ステップＳ５の比較判定工程において比較判定式（９）を充足しなければ、曲げ補強部３１，４１やせん断補強部３２，３３，４２，４３の幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sが設定された梁１は設計用曲げモーメントＭ_dに耐えることができず、設定された幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sが不適切である。 (F) Step S6: Change of set values of width and thickness of bending reinforcement portion and shear reinforcement portion As shown in points D2 and D4 shown in FIG. 9, the comparison determination formula (8) is satisfied in the comparison determination step of step S5. Otherwise, the beam 1 having the width B _s and the thickness t _{s of} the shear reinforcing portions 32, 33, 42, 43 cannot withstand the design shear force Q _d , and the set width B _b , B _s and thickness t _b , t _s are inappropriate. Further, as in the points D3 and D4 shown in FIG. 9, if the comparison determination formula (9) is not satisfied in the comparison determination step of step S5, the bending reinforcement portions 31, 41 and the shear reinforcement portions 32, 33, 42, 43 Beam 1 with widths B _b , B _s and thicknesses t _b , t _s cannot withstand the design bending moment M _d , and the set widths B _b , B _s and thickness t _b , t _s is inappropriate.

そこで、判別式（８），（９）のどちらか一方又は両方を充足しない場合には、曲げ補強部３１，４１とせん断補強部３２，３３，４２，４３の幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sの設定値を変更することによって、曲げ補強部３１，４１とせん断補強部３２，３３，４２，４３の幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sを再度設定する。或いは、フランジ２２，２３の降伏点σ_yf，ウエブ２１の降伏点σyw，曲げ補強部３１，４１の降伏点σyb，せん断補強部３２，３３，４２，４３の降伏点σysのうち少なくとも１つをより高い設定値に変更することによって、降伏点σ_yf，降伏点σ_yw，降伏点σ_yb及び降伏点σ_ysのうち少なくとも１つを再度設定する。
その後、ステップＳ３に戻って、ステップＳ３の再計算によってせん断耐力Ｑ_c及び曲げ耐力Ｍ_c1，Ｍ_c2を再度計算し、ステップＳ４における判別式（８），（９）を再度定めて、ステップＳ５において設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dが変更後の判別式（８），（９）を充足するか否か判定する。こうして、ステップＳ５の比較判定工程において比較判定式（８）及び比較判定式（９）の両方を充足するまで、ステップＳ６，Ｓ３，Ｓ４，Ｓ５の工程を繰り返す。 Therefore, when either one or both of the discriminants (8) and (9) are not satisfied, the widths B _b , B _s and thickness of the bending reinforcing portions 31, 41 and the shear reinforcing portions 32, 33, 42, 43 are not satisfied. By changing the set values of t _b and t _s , the widths B _b and B _s and the thicknesses t _b and t _s of the bending reinforcing portions 31, 41 and the shear reinforcing portions 32, 33, 42 and 43 are set again. To do. Alternatively, at least one of the yield point σ _yf of the flanges 22 and 23, the yield point σ _{yw of} the web 21, the yield point σyb of the bending reinforcing portions 31 and 41, and the yield point σ ys of the shear reinforcing portions 32, 33, 42, 43 is set. By changing to a higher setting value, at least one of the yield point σ _yf , the yield point σ _yw , the yield point σ _yb, and the yield point σ _ys is set again.
After that, returning to step S3, the shear strength Q _c and the bending strengths M _c1 and M _c2 are recalculated by the recalculation of step S3, and the discriminants (8) and (9) in step S4 are redefined, and step S5. Whether or not the design shear force Q _d and the design bending moment M _d satisfy the changed discriminants (8) and (9) is determined. In this way, the steps S6, S3, S4, and S5 are repeated until both the comparison determination formula (8) and the comparison determination formula (9) are satisfied in the comparison determination step of step S5.

（Ｇ）ステップＳ７：決定（本設定）
図９に示す点Ｄ1のように、ステップＳ５の比較判定工程において比較判定式（８）及び比較判定式（９）の両方を充足すれば、ステップＳ２又はステップＳ６において幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sが設定された梁１は設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dに耐え得る。従って、ステップＳ２又はステップＳ６において設定された幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sが適切である。よって、曲げ補強部３１，４１やせん断補強部３２，３３，４２，４３の幅や厚さをステップＳ２又はステップＳ６において設定された数値Ｂ_b，Ｂ_s及びｔ_b，ｔ_sに決定する。併せて、鉄骨梁本体２の梁成、フランジ２２，２３の幅、ウエブ２１の厚さ、フランジ２２，２３の厚さ、開口２４の直径、曲げ補強部３１の上端から曲げ補強部４１の下端までの距離、フランジ２２，２３の降伏点、ウエブ２１の降伏点、曲げ補強部３１，４１の降伏点、せん断補強部３２，３３，４２，４３の降伏点、梁軸方向に対するせん断補強部３２，３３，４２，４３の延在方向の成す角を、ステップＳ２において設定した数値Ｄ，Ｂ，ｔ_w，ｔ_f，φ，Ｈ_b，σ_yf，σ_yw，σ_yb，σ_ys，θに決定する。
以上により、梁１の評価・設計が終了する。 (G) Step S7: Decision (this setting)
As shown at point D1 shown in FIG. 9, if both the comparison determination formula (8) and the comparison determination formula (9) are satisfied in the comparison determination step of step S5, the widths B _b , B _s and the widths B _b , B _s and in step S2 or step S6 are satisfied. The beam 1 having the thicknesses t _b and t _s can withstand the design shear force Q _d and the design bending moment M _d . Therefore, the widths B _b , B _s and the thicknesses t _b , t _s set in step S2 or step S6 are appropriate. Therefore, the widths and thicknesses of the bending reinforcing portions 31, 41 and the shear reinforcing portions 32, 33, 42, 43 are determined to be the numerical values B _b , B _s and t _b , t _s set in step S2 or step S6. At the same time, the beam formation of the steel beam main body 2, the widths of the flanges 22 and 23, the thickness of the web 21, the thickness of the flanges 22 and 23, the diameter of the opening 24, the upper end of the bending reinforcing portion 31 to the lower end of the bending reinforcing portion 41. Distance to, the yield point of the flanges 22, 23, the yield point of the web 21, the yield point of the bending reinforcing portions 31, 41, the yield point of the shear reinforcing portions 32, 33, 42, 43, the shear reinforcing portion 32 in the beam axial direction. The angles formed by the extending directions of, 33, 42, and 43 are set to the numerical values D, B, t _w , t _f , φ, H _b , σ _yf , σ _yw , σ _yb , σ _ys , and θ set in step S2. decide.
This completes the evaluation and design of the beam 1.

３．梁の製造
上述の設計方法によって決定した設計値に従って梁１を製造する。具体的には、まず、ステップＳ７で決定した幅Ｂ_b、厚さｔ_b及び降伏点σ_ybの曲げ補強部３１，４１と、ステップＳ７で決定した幅Ｂ_s、厚さｔ_s及び降伏点σ_ysのせん断補強部３２，３３，４２，４３とを有した鋼製補強材３，４を準備する。更に、ステップＳ７で決定した幅Ｂ、厚さｔ_f及び降伏点σ_yfのフランジ２２，２３と、ステップＳ７で決定した厚さｔ_w、高さ（Ｄ−２ｔ_f）及び降伏点σ_ywのウエブ２１と、直径φの開口２４とを有した梁成Ｄの鉄骨梁本体２を準備する。そして、梁軸方向に対するせん断補強部３２，３３，４２，４３の延在方向の成す角がステップＳ７で決定した設計値θになるように、且つ、曲げ補強部３１の上端から曲げ補強部４１の下端までの距離がステップＳ７で決定した設計値Ｈ_bになるように、曲げ補強部３１，４１及びせん断補強部３２，３３，４２，４３を鉄骨梁本体２のウエブ２１に接合する。こうして製造した梁１を柱間に架設する。 3. 3. Manufacture of Beam Beam 1 is manufactured according to the design value determined by the above design method. Specifically, first, the width B _b determined at step S7, and the bending reinforcement portion 31, 41 having a thickness of t _b and yield point sigma _yb, width B _s determined in step S7, the thickness t _s and a yield point Steel reinforcing members 3 and 4 having shear reinforcing portions 32, 33, 42 and 43 of σ _ys are prepared. Furthermore, the width B is determined in step S7, the flange 22, 23 thickness t _f and yield point sigma _yf, the thickness t _w determined in step S7, the height (D-2t _f) and yield point sigma _yw of A steel beam main body 2 of a beam D having a web 21 and an opening 24 having a diameter φ is prepared. Then, the angle formed by the shear reinforcing portions 32, 33, 42, 43 in the extending direction with respect to the beam axial direction becomes the design value θ determined in step S7, and the bending reinforcing portion 41 is formed from the upper end of the bending reinforcing portion 31. The bending reinforcing portions 31, 41 and the shear reinforcing portions 32, 33, 42, 43 are joined to the web 21 of the steel beam main body 2 so that the distance to the lower end of the beam becomes the design value H _b determined in step S7. The beam 1 manufactured in this way is erected between the columns.

４．効果
以上の評価方法・設計方法では、せん断力のみならず曲げモーメントも考慮して、梁１が設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dに耐え得るように、曲げ補強部３１，４１とせん断補強部３２，３３，４２，４３の幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sの値を決定した。そのため、曲げ補強部３１，４１とせん断補強部３２，３３，４２，４３の幅Ｂ_b，Ｂ_s及び厚さｔ_b，ｔ_sを過不足なく適切に設計することができる。そのため、曲げ補強部３１，４１とせん断補強部３２，３３，４２，４３の材料費の増大を抑えることができるとともに、梁１の開口２４の部分の耐力が不足することを防止できる。 4. Effect In the above evaluation method and design method, not only the shear force but also the bending moment is taken into consideration so that the beam 1 can withstand the design shear force Q _d and the design bending moment M _d. The values of the widths B _b , B _s and the thicknesses t _b , t _s of the shear reinforcing portions 32, 33, 42, 43 were determined. Therefore, the widths B _b , B _s and the thicknesses t _b , t _s of the bending reinforcing portions 31, 41 and the shear reinforcing portions 32, 33, 42, 43 can be appropriately designed without excess or deficiency. Therefore, it is possible to suppress an increase in the material cost of the bending reinforcing portions 31, 41 and the shear reinforcing portions 32, 33, 42, 43, and it is possible to prevent the proof stress of the opening 24 portion of the beam 1 from being insufficient.

５．変形例
鉄骨梁本体２はＨ形鋼であったが、梁軸方向に帯状に延びた鉛直な縦板部と、縦板部の上下端に設けられるとともに梁軸方向に帯状に延びた水平な横板部とを備える形鋼（例えば山形鋼、溝形鋼、リップ溝形鋼、Ｚ形鋼、Ｔ形鋼、角形鋼管）であれば、Ｈ形鋼以外であってもよい。 5. Modification example The steel beam body 2 was H-shaped steel, but it was provided in a vertical vertical plate portion extending in a strip shape in the beam axial direction and a horizontal plate portion provided in the upper and lower ends of the vertical plate portion and extending in a strip shape in the beam axial direction. A section steel having a horizontal plate portion (for example, angle steel, channel steel, lip channel steel, Z section steel, T section steel, square steel tube) may be other than H section steel.

６．具体例
以下に、梁１の各部の寸法及び降伏点の具体的な数値を挙げて、具体的に梁１の評価・設計をする。 6. Specific Examples Below, specific numerical values of the dimensions and yield points of each part of the beam 1 are given, and the beam 1 is specifically evaluated and designed.

梁１の各部の寸法及び降伏点を以下のように設定する。

The dimensions and yield points of each part of the beam 1 are set as follows.

また、梁１の設計用荷重から設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dを解析して、設計用せん断力Ｑ_d及び設計用曲げモーメントＭ_dを以下のように設定する。

Further, the design shear force Q _d and the design bending moment M _d are analyzed from the design load of the beam 1, and the design shear force Q _d and the design bending moment M _d are set as follows.

式（１）に従って開口２４を有する鉄骨梁本体２のせん断耐力Ｑ_cgを計算すると、次の通りである。

The shear strength Q _cg of the steel beam main body 2 having the opening 24 is calculated according to the equation (1) as follows.

式（２）に従ってせん断補強部３２，３３，４２，４３のせん断耐力Ｑ_crを計算すると、次の通りである。

The shear strength Q _cr of the

shear reinforcing portions

32, 33, 42, and 43 is calculated according to the equation (2) as follows.

式（３）に従って梁１の開口２４の部分のせん断耐力Ｑ_cを計算すると、次の通りである。

Calculating the shear strength Q _c of the portion of the opening 24 of the beam 1 according to equation (3), it is as follows.

式（４）に従って開口２４を有する鉄骨梁本体２の曲げ耐力Ｍ_c1gを計算すると、次の通りである。

The bending strength M _{c1 g} of the steel beam main body 2 having the opening 24 is calculated according to the equation (4) as follows.

次式（５）に従って曲げ補強部３１，４１の曲げ耐力Ｍ_c1rを計算すると、次の通りである。

The bending strength M _c1r of the

bending reinforcing portions

31 and 41 is calculated according to the following equation (5) and is as follows.

式（６）に従って第一曲げ耐力Ｍ_c1を計算すると、次の通りである。

The first bending strength M _c1 is calculated according to the equation (6) as follows.

式（７）に従って第二曲げ耐力Ｍ_c2を計算すると、次の通りである。

The second bending strength M _c2 is calculated according to the equation (7) and is as follows.

図１０に示すように、点Ａ、点Ｂ及び点Ｃをグラフにプロットし、線ＡＢＣをグラフに設定する。つまり、せん断耐力Ｑ_c及び曲げ耐力Ｍ_c1，Ｍ_c2から線ＡＢの傾きを算出し、第一曲げ耐力Ｍ_c1を線ＡＢの切片とし、線ＡＢを表す一次関数を設定する。この一次関数に設計用せん断力Ｑ_dを当て嵌める。これにより、せん断力Ｑが設計用せん断力Ｑ_dである場合の曲げ耐力Ｍ_cを計算する。

As shown in FIG. 10, points A, B and C are plotted on the graph and line ABC is set on the graph. That is, the slope of the line AB is calculated from the shear strength Q _c and the bending strengths M _c1 and M _c2 , the first bending strength M _c1 is used as the intercept of the line AB, and a linear function representing the line AB is set. The design shear force Q _d is applied to this linear function. As a result, the bending proof stress M _c when the shear force Q is the design shear force Q _d is calculated.

そして、せん断耐力Ｑ_c（＝825 kN）と設計用せん断力Ｑ_d（＝600 kN）を比較すると、せん断耐力Ｑ_cが設計用せん断力Ｑ_dよりも大きい。また、曲げ耐力Ｍ_c（＝725 kN・m）と設計用曲げモーメントＭ_d(＝710 kN・m)を比較すると、曲げ耐力Ｍ_cが設計用曲げモーメントＭ_dよりも大きい。つまり、図１０に示すように、点Ｄをグラフにプロットすると、点Ｄが線ＢＣの左側且つ線ＡＢの下側の領域にある。
よって、梁１の各部の寸法及び降伏点の設定値（表２）が適切であり、梁１の各部の寸法及び降伏点の設計値をその設定値に決定する。この梁１の各部の寸法及び降伏点の設計値に従って、梁１を製造する。 Comparing the shear strength Q _c (= 825 kN) and the design shear strength Q _d (= 600 kN), the shear strength Q _c is larger than the design shear strength Q _d . Comparing the bending proof stress M _c (= 725 kN ・ m) and the design bending moment M _d (= 710 kN ・ m), the bending proof stress M _c is larger than the design bending moment M _d . That is, as shown in FIG. 10, when the point D is plotted on the graph, the point D is in the region on the left side of the line BC and below the line AB.
Therefore, the set values of the dimensions and the yield point of each part of the beam 1 (Table 2) are appropriate, and the design values of the dimensions and the yield point of each part of the beam 1 are determined as the set values. The beam 1 is manufactured according to the dimensions of each part of the beam 1 and the design value of the yield point.

１…梁，２…鉄骨梁本体，３，４…鋼製補強材，２１…ウエブ（縦板部），２２，２３…フランジ（横板部），２４…開口，３１，４１…曲げ補強部，３２，３３，４２，４３…せん断補強部 1 ... Beam, 2 ... Steel beam body, 3,4 ... Steel reinforcement, 21 ... Web (vertical plate), 22, 23 ... Flange (horizontal plate), 24 ... Opening, 31, 41 ... Bending reinforcement , 32, 33, 42, 43 ... Shear reinforcement

Claims

A steel beam main body having a vertical vertical plate portion extending in the beam axial direction, horizontal horizontal plate portions provided above and below the vertical plate portion, and openings formed in the vertical plate portion.
A bending reinforcing portion joined to the vertical plate portion so as to extend in the beam axial direction above and below the opening, and a bending reinforcing portion.
In a method for evaluating a beam including a shear reinforcing portion joined to the vertical plate portion so as to extend in a direction oblique to the beam axial direction on both sides of the opening in the beam axial direction.
A setting process for setting the width and thickness of the bending reinforcing portion and the shear reinforcing portion, and
A step of determining the relationship between the bending strength and the shearing strength of the opening portion of the beam based on the width and thickness of the bending reinforcing portion and the shear reinforcing portion set in the setting step.
A setting process that determines the design shear force and design bending moment assumed for the beam, and
A comparison step of comparing the design shear force and the design bending moment with the relationship is provided .
The process of determining the relationship is
A first calculation step of calculating the shear strength of the opening portion of the beam based on the width and thickness of the shear reinforcing portion set in the setting step.
Based on the width and thickness of the bending reinforcing portion set in the setting step, the first bending strength of the opening portion of the beam when the shear force does not act on the opening portion of the beam is calculated. A second calculation step of calculating the second bending strength of the opening portion of the beam when a shear force corresponding to the shear strength acts on the opening portion of the beam.
It has a step of determining a linear function with the quotient obtained by dividing the difference between the second bending proof stress and the first bending proof stress by the shearing proof stress as an intercept and using the first bending proof stress as an intercept.
The comparison step is
It has a step of comparing the design shearing force and the shearing force, and comparing the bending force obtained by applying the design shearing force to the linear function and the design bending moment. > A beam evaluation method characterized by that.