JP5911692B2 - Fireproof reinforcement structure for concrete filled steel tubular columns - Google Patents

Fireproof reinforcement structure for concrete filled steel tubular columns Download PDF

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JP5911692B2
JP5911692B2 JP2011221295A JP2011221295A JP5911692B2 JP 5911692 B2 JP5911692 B2 JP 5911692B2 JP 2011221295 A JP2011221295 A JP 2011221295A JP 2011221295 A JP2011221295 A JP 2011221295A JP 5911692 B2 JP5911692 B2 JP 5911692B2
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steel pipe
column
heat insulating
stiffening rib
insulating material
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JP2013079553A (en
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俊彦 西村
俊彦 西村
俊夫 斉藤
俊夫 斉藤
満 竹内
満 竹内
長岡　勉
勉 長岡
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Takenaka Corp
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本発明は、コンクリート充填鋼管柱の耐火補強構造に関する。   The present invention relates to a fireproof reinforcing structure for a concrete-filled steel pipe column.

従来から、吹付けロックウールによって鉄骨柱を被覆する鉄骨柱の耐火被覆構造が知られている。また、耐火シートによって鉄骨柱を被覆する鉄骨柱の耐火被覆構造が知られている（例えば、特許文献１）。   Conventionally, a fireproof covering structure of a steel column that covers a steel column with spray rock wool is known. Moreover, the fireproof covering structure of the steel column which coat | covers a steel column with a fireproof sheet is known (for example, patent document 1).

一方、鋼管柱内にコンクリートが充填されたコンクリート充填鋼管（ＣＦＴ（Ｃｏｎｃｒｅｔｅ Ｆｉｌｌｅｄ Ｓｔｅｅｌ Ｔｕｂｅ））柱が知られている。ＣＦＴ柱では、一般に、中空の鋼管柱と比較して負担可能な軸力が大きく、またコンクリートが充填されている分、熱容量が増加するため、耐火性能に優れている。そのため、設計条件（例えば、柱の負担軸力が比較的小さく火災継続時間が短い場合など）によっては、ＣＦＴ柱の耐火被覆を省略することが可能である。   On the other hand, a concrete filled steel tube (CFT) column in which concrete is filled in a steel tube column is known. In general, the CFT column is superior in fire resistance because the axial force that can be borne is larger than that of a hollow steel tube column and the heat capacity is increased by filling the concrete. Therefore, depending on the design conditions (for example, when the load axial force of the column is relatively small and the fire duration time is short), it is possible to omit the fireproof coating of the CFT column.

特開２０１０−２６５６０５号公報JP 2010-265605 A

ところで、コンクリート充填鋼管柱では、火災時の温度上昇に伴って鋼管柱に局部座屈が発生し易くなる。鋼管柱に局部座屈が発生すると、コンクリート充填鋼管柱の軸方向変位が急激に進展して崩壊に至る可能性がある。   By the way, in a concrete filling steel pipe column, local buckling becomes easy to generate | occur | produce in a steel pipe column with the temperature rise at the time of a fire. When local buckling occurs in the steel pipe column, the axial displacement of the concrete-filled steel pipe column may rapidly develop and collapse.

この対策として、前述した吹付けロックウールや耐火シートで鋼管柱を耐火被覆し、鋼管柱の温度上昇を抑制することが考えられる。   As a countermeasure against this, it is conceivable to cover the steel pipe column with the above-described spray rock wool or fireproof sheet to prevent the temperature rise of the steel pipe column.

しかしながら、鋼管柱の温度上昇を充分に抑制するためには、吹付けロックウール等の耐火被覆の厚みが増えて、コストがかかる。   However, in order to sufficiently suppress the temperature rise of the steel pipe column, the thickness of the fireproof coating such as spray rock wool increases and costs increase.

本発明は、上記の事実を考慮し、鋼管柱の局部座屈を抑制しつつ、断熱材の被覆厚を薄くすることができるコンクリート充填鋼管柱の耐火補強構造を得ることを目的とする。   In view of the above facts, an object of the present invention is to obtain a fireproof reinforcing structure for a concrete-filled steel pipe column that can reduce the coating thickness of a heat insulating material while suppressing local buckling of the steel pipe column.

請求項１に記載のコンクリート充填鋼管柱の耐火補強構造は、鋼管柱と、前記鋼管柱内に充填された充填コンクリートと、前記鋼管柱の外側面に設けられた補剛リブと、前記補剛リブに隣接して配置され、前記鋼管柱の外側面を被覆する断熱材と、前記断熱材を間に置いて前記鋼管柱の前記外側面と対向すると共に、前記補剛リブに支持された仕上げ材と、を備えている。 The fire-proof reinforcement structure for a concrete-filled steel pipe column according to claim 1 includes a steel pipe column, filled concrete filled in the steel pipe column, stiffening ribs provided on an outer surface of the steel pipe column, and the stiffening A heat insulating material disposed adjacent to the rib and covering the outer surface of the steel pipe column; and a finish supported by the stiffening rib while facing the outer surface of the steel pipe column with the heat insulating material interposed therebetween. Material .

請求項１に係るコンクリート充填鋼管柱の耐火補強構造によれば、鋼管柱の外側面に補剛リブが設けられている。この補剛リブによって鋼管柱の側壁に面外剛性を付与することにより、火災時の温度上昇に伴う鋼管柱の側壁の局部座屈が抑制される。従って、補剛リブを備えない構成と比較して、鋼管柱の外側面を被覆する断熱材の被覆厚を薄くすることができる。   According to the fireproof reinforcing structure for a concrete-filled steel pipe column according to claim 1, the stiffening rib is provided on the outer surface of the steel pipe column. By giving out-of-plane rigidity to the side wall of the steel pipe column by this stiffening rib, local buckling of the side wall of the steel pipe column accompanying a temperature rise at the time of a fire is suppressed. Therefore, compared with the structure which is not provided with a stiffening rib, the coating thickness of the heat insulating material which coat | covers the outer surface of a steel pipe column can be made thin.

また、補剛リブに隣接して断熱材を設けたことにより、断熱材の熱吸収容量によって補剛リブの温度上昇が抑制される。これにより、鋼管柱の側壁に対する補剛リブの補剛効果、即ち、鋼管柱の側壁の局部座屈の抑制効果が長期化される。従って、コンクリート充填鋼管柱の耐火性能が向上する。
さらに、補剛リブで仕上げ材を支持することにより、例えば、図１５に示される従来の仕上げ構造１２０のように、コンクリート充填鋼管柱１０から外側へ離れた位置に立てられた軽鉄スタッド１２４で仕上げ材１２６を支持する構成と比較して、仕上げ材を含めた柱の水平断面積を小さくすることができる。従って、室内スペースを広げることができる。更に、コンクリート充填鋼管柱１０の周りに軽鉄スタッド１２４を立てる作業が不要になるため、従来の仕上げ構造１２０と比較して施工性が向上する。
さらにまた、仕上げ材によって断熱材を覆うことにより、断熱材が火災に直接曝されないため、断熱材の消失等が抑制される。これにより、仕上げ材を備えない構成と比較して、断熱材の断熱効果が長期的されるため、コンクリート充填鋼管柱の耐火性能が更に向上する。 Further, since the heat insulating material is provided adjacent to the stiffening rib, the temperature increase of the stiffening rib is suppressed by the heat absorption capacity of the heat insulating material. Thereby, the stiffening effect of the stiffening rib on the side wall of the steel pipe column, that is, the effect of suppressing the local buckling of the side wall of the steel pipe column is prolonged. Therefore, the fire resistance performance of the concrete-filled steel pipe column is improved.
Further, by supporting the finishing material with the stiffening ribs, for example, with a light iron stud 124 erected away from the concrete-filled steel pipe column 10 as in the conventional finishing structure 120 shown in FIG. Compared to the configuration that supports the finishing material 126, the horizontal cross-sectional area of the column including the finishing material can be reduced. Therefore, the indoor space can be expanded. Furthermore, since the operation | work which raises the light iron stud 124 around the concrete filling steel pipe column 10 becomes unnecessary, workability improves compared with the conventional finishing structure 120. FIG.
Furthermore, since the heat insulating material is not directly exposed to the fire by covering the heat insulating material with the finishing material, the disappearance of the heat insulating material is suppressed. Thereby, since the heat insulation effect of a heat insulating material is prolonged compared with the structure which is not provided with a finishing material, the fireproof performance of a concrete filling steel pipe column further improves.

請求項２に記載のコンクリート充填鋼管柱の耐火補強構造は、請求項１に記載のコンクリート充填鋼管柱の耐火補強構造において、前記断熱材が、前記補剛リブの側面を被覆する。   The fireproof reinforcing structure for concrete-filled steel pipe columns according to claim 2 is the fireproof reinforcing structure for concrete-filled steel pipe columns according to claim 1, wherein the heat insulating material covers the side surfaces of the stiffening ribs.

請求項２に係るコンクリート充填鋼管柱の耐火補強構造によれば、断熱材によって補剛リブの側面を被覆したことにより、火災時の補剛リブの温度上昇が更に抑制される。これにより、鋼管柱の側壁に対する補剛リブの補剛効果、即ち、鋼管柱の側壁の局部座屈の抑制効果が長期化される。従って、コンクリート充填鋼管柱の耐火性能が更に向上する。   According to the fireproof reinforcing structure for a concrete-filled steel pipe column according to claim 2, the temperature rise of the stiffening rib during a fire is further suppressed by covering the side surface of the stiffening rib with a heat insulating material. Thereby, the stiffening effect of the stiffening rib on the side wall of the steel pipe column, that is, the effect of suppressing the local buckling of the side wall of the steel pipe column is prolonged. Therefore, the fire resistance performance of the concrete-filled steel pipe column is further improved.

請求項３に記載のコンクリート充填鋼管柱の耐火補強構造は、請求項１又は請求項２に記載のコンクリート充填鋼管柱の耐火補強構造において、前記仕上げ材が、前記補剛リブ及び前記断熱材に支持される。 The fireproof reinforcement structure for a concrete-filled steel pipe column according to claim 3 is the fireproof reinforcement structure for a concrete-filled steel pipe column according to claim 1 or 2, wherein the finishing material is provided on the stiffening rib and the heat insulating material. Supported.

請求項３に係るコンクリート充填鋼管柱の耐火補強構造によれば、補剛リブ及び断熱材で仕上げ材を支持することにより、前述したように、仕上げ材を含めた柱の水平断面積を小さくすることができる。 According to the fireproof reinforcement structure of a concrete-filled steel pipe column according to claim 3, as described above , the horizontal cross-sectional area of the column including the finishing material is reduced by supporting the finishing material with the stiffening rib and the heat insulating material. be able to.

請求項４に記載のコンクリート充填鋼管柱の耐火補強構造は、請求項１〜請求項３の何れか１項に記載のコンクリート充填鋼管柱の耐火補強構造において、前記補剛リブが、前記鋼管柱の周方向に沿って配置されると共に該鋼管柱の軸方向に間隔を空けて複数設けられ、前記断熱材が、前記鋼管柱の軸方向に隣接する前記補剛リブの間に設けられている。   The fireproof reinforcement structure for a concrete-filled steel pipe column according to claim 4 is the fireproof reinforcement structure for a concrete-filled steel pipe column according to any one of claims 1 to 3, wherein the stiffening rib is the steel pipe column. Are arranged along the circumferential direction of the steel pipe column and spaced apart in the axial direction of the steel pipe column, and the heat insulating material is provided between the stiffening ribs adjacent in the axial direction of the steel pipe column. .

請求項４に係るコンクリート充填鋼管柱の耐火補強構造によれば、補剛リブが鋼管柱の周方向（柱周方向）に沿って配置されている。これにより、鋼管柱の側壁に曲げ剛性を付与せずに、若しくはその付与量を小さく抑えつつ、当該側壁に面外剛性を付与することができる。つまり、補剛リブ付近で鋼管柱の曲げ剛性を急激に変化させずに、鋼管柱に面外剛性を付与することができる。従って、曲げ剛性の急激な変化に伴う応力集中が低減されるため、鋼管柱の補剛リブ付近での局部座屈が抑制される。   According to the fireproof reinforcing structure for a concrete-filled steel pipe column according to claim 4, the stiffening ribs are arranged along the circumferential direction (column circumferential direction) of the steel pipe column. Thereby, out-of-plane rigidity can be given to the said side wall, without giving bending rigidity to the side wall of a steel pipe column, or suppressing the provision amount small. That is, out-of-plane rigidity can be imparted to the steel pipe column without abruptly changing the bending rigidity of the steel pipe column in the vicinity of the stiffening rib. Therefore, since the stress concentration accompanying the rapid change in bending rigidity is reduced, local buckling in the vicinity of the stiffening rib of the steel pipe column is suppressed.

本発明は、上記の構成としたので、鋼管柱の局部座屈を抑制しつつ、断熱材の被覆厚を薄くすることができる。   Since this invention was set as said structure, the coating thickness of a heat insulating material can be made thin, suppressing the local buckling of a steel pipe column.

本発明の第１実施形態に係るコンクリート充填鋼管柱の耐火補強構造が適用されたコンクリート充填鋼管柱を示す立面図である。It is an elevation view which shows the concrete filling steel pipe column to which the fireproof reinforcement structure of the concrete filling steel pipe column which concerns on 1st Embodiment of this invention was applied. （Ａ）は図１の２Ａ−２Ａ線断面図であり、（Ｂ）は本発明の第１実施形態における断熱材及び仕上げ材の取付方法を説明する説明図である。(A) is the sectional view on the 2A-2A line of FIG. 1, (B) is explanatory drawing explaining the attachment method of the heat insulating material and finishing material in 1st Embodiment of this invention. 本発明の第１実施形態におけるコンクリート充填鋼管柱の応力状態を示す縦断面図である。It is a longitudinal cross-sectional view which shows the stress state of the concrete filling steel pipe column in 1st Embodiment of this invention. （Ａ）は図２（Ａ）の一部を示す断面図であり、（Ｂ）は本発明の第１実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図４（Ａ）に相当する断面図であり、（Ｃ）は比較例に係るコンクリート充填鋼管柱を示す図４（Ａ）に相当する断面図である。(A) is sectional drawing which shows a part of FIG. 2 (A), (B) is a concrete filling steel pipe to which the modification of the fireproof reinforcement structure of the concrete filling steel pipe column which concerns on 1st Embodiment of this invention was applied. It is sectional drawing equivalent to FIG. 4 (A) which shows a pillar, (C) is sectional drawing equivalent to FIG. 4 (A) which shows the concrete filling steel pipe pillar which concerns on a comparative example. 一般的なコンクリート充填鋼管柱と梁で構成された架構を示す立面図であり、（Ａ）は火災前の状態を示し、（Ｂ）は火災後の状態を示している。It is an elevation view which shows the frame comprised with the general concrete filling steel pipe pillar and beam, (A) shows the state before a fire, (B) has shown the state after a fire. 一般的なコンクリート充填鋼管柱の耐火性能評価に用いられる実験評価モデルを示すモデル図であり、（Ａ）は水平力を載荷する前の状態を示し、（Ｂ）は水平力が載荷された際のコンクリート充填鋼管柱の変形状態、及び応力状態を示し、（Ｃ）はコンクリート充填鋼管柱を構成する鋼管柱に局部座屈が発生した状態を示している。It is a model figure which shows the experimental evaluation model used for the fireproof performance evaluation of a general concrete filling steel pipe column, (A) shows the state before loading horizontal force, and (B) is when horizontal force is loaded. The deformation state and stress state of the concrete-filled steel pipe column are shown, and (C) shows a state where local buckling has occurred in the steel pipe column constituting the concrete-filled steel pipe column. 本発明の第２実施形態に係るコンクリート充填鋼管柱の耐火補強構造が適用されたコンクリート充填鋼管柱を示す立面図である。It is an elevation which shows the concrete filling steel pipe column to which the fireproof reinforcement structure of the concrete filling steel pipe column concerning 2nd Embodiment of this invention was applied. 図７の８−８線断面図である。FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7. 本発明の第２実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図８に相当する断面図である。It is sectional drawing equivalent to FIG. 8 which shows the concrete filling steel pipe pillar to which the modification of the fireproof reinforcement structure of the concrete filling steel pipe pillar concerning 2nd Embodiment of this invention was applied. （Ａ）は図８の１０−１０線断面図であり、（Ｂ）は、本発明の第２実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図１０（Ａ）に相当する断面図である。(A) is a cross-sectional view taken along line 10-10 in FIG. 8, and (B) is a concrete-filled steel pipe column to which a modification of the fireproof reinforcement structure for a concrete-filled steel pipe column according to the second embodiment of the present invention is applied. FIG. 11 is a cross-sectional view corresponding to FIG. （Ａ）及び（Ｂ）は、本発明の第２実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図１０（Ａ）に相当する断面図である。(A) And (B) is sectional drawing equivalent to FIG. 10 (A) which shows the concrete filling steel pipe pillar to which the modification of the fireproof reinforcement structure of the concrete filling steel pipe pillar concerning 2nd Embodiment of this invention was applied. is there. （Ａ）及び（Ｂ）は、本発明の第１実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図４（Ａ）に相当する断面図である。(A) And (B) is sectional drawing equivalent to FIG. 4 (A) which shows the concrete filling steel pipe column to which the modification of the fireproof reinforcement structure of the concrete filling steel pipe column concerning 1st Embodiment of this invention was applied. is there. 本発明の第１実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図４（Ａ）に相当する断面図である。It is sectional drawing equivalent to FIG. 4 (A) which shows the concrete filling steel pipe pillar to which the modification of the fireproof reinforcement structure of the concrete filling steel pipe pillar concerning 1st Embodiment of this invention was applied. 本発明の第２実施形態に係るコンクリート充填鋼管柱の耐火補強構造の変形例が適用されたコンクリート充填鋼管柱を示す図であり、（Ａ）は図１４（Ｂ）の１４Ａ−１４Ａ線断面図であり、（Ｂ）は図１４（Ａ）の１４Ｂ−１４Ｂ断面図である。It is a figure which shows the concrete filling steel pipe pillar to which the modification of the fireproof reinforcement structure of the concrete filling steel pipe pillar concerning 2nd Embodiment of this invention was applied, (A) is 14A-14A sectional view taken on the line of FIG. 14 (B). FIG. 14B is a cross-sectional view taken along the line 14B-14B in FIG. 従来のコンクリート充填鋼管柱の仕上げ構造を示す図２（Ａ）に相当する断面図である。It is sectional drawing equivalent to FIG. 2 (A) which shows the finishing structure of the conventional concrete filling steel pipe column.

以下、図面を参照しながら、本発明の実施形態に係るコンクリート充填鋼管柱の耐火補強構造について説明する。なお、各図において適宜示される矢印Ｘは鋼管柱の幅方向（柱幅方向）を示し、矢印Ｙは矢印Ｘ方向と直交する鋼管柱の他の幅方向（柱幅方向）を示し、矢印Ｚは鋼管柱の軸方向（柱軸方向、上下方向）を示している。   Hereinafter, a fireproof reinforcing structure for a concrete-filled steel pipe column according to an embodiment of the present invention will be described with reference to the drawings. In addition, the arrow X suitably shown in each figure shows the width direction (column width direction) of a steel pipe column, the arrow Y shows the other width direction (column width direction) of the steel pipe column orthogonal to the arrow X direction, and arrow Z Indicates the axial direction of the steel pipe column (column axis direction, vertical direction).

先ず、第１実施形態について説明する。   First, the first embodiment will be described.

図１には、一例として、第１実施形態に係るコンクリート充填鋼管柱の耐火補強構造（以下、単に「耐火補強構造」という）２０が適用されたコンクリート充填鋼管柱１０が示されている。コンクリート充填鋼管柱１０は、鋼管柱１２と、鋼管柱１２内に充填される充填コンクリート１４（図２（Ａ）参照）とを備えている。鋼管柱１２は角形鋼管で構成されており、水平部材としての鉄骨梁１６が接合される上下の鋼管仕口部１２Ａと、これらの鋼管仕口部１２Ａの間に延びる鋼管本体部１２Ｂとを有している。この鋼管本体部１２Ｂに、本実施形態に係る耐火補強構造２０が適用されている。   FIG. 1 shows, as an example, a concrete-filled steel pipe column 10 to which a concrete-filled steel pipe column fireproof reinforcement structure (hereinafter simply referred to as “fireproof reinforcement structure”) 20 according to the first embodiment is applied. The concrete-filled steel pipe column 10 includes a steel pipe column 12 and filled concrete 14 (see FIG. 2A) filled in the steel pipe column 12. The steel pipe column 12 is formed of a square steel pipe, and has an upper and lower steel pipe joint portion 12A to which a steel beam 16 as a horizontal member is joined, and a steel pipe main body portion 12B extending between these steel pipe joint portions 12A. doing. The fireproof reinforcing structure 20 according to the present embodiment is applied to the steel pipe main body 12B.

鉄骨梁１６はＨ形鋼で構成され、上下一対のフランジ部１６Ａとフランジ部１６Ａを繋ぐウェブ部１６Ｂを有し、その端部が鋼管仕口部１２Ａの外側面に突き当てられて溶接等によって接合されている。一方、鋼管仕口部１２Ａの内側面には、上下一対の内ダイアフラム１８が設けられている。各内ダイアフラム１８は、鉄骨梁１６のフランジ部１６Ａと連続するように設けられており、この内ダイアフラム１８によって鋼管仕口部１２Ａが補強されている。また、各内ダイアフラム１８の中央部には充填孔１８Ａ（図３参照）が形成されており、これらの充填孔１８Ａを通して鋼管柱１２内に充填コンクリート１４が充填されるようになっている。   The steel beam 16 is made of H-shaped steel, and has a pair of upper and lower flange portions 16A and a web portion 16B that connects the flange portion 16A. The end of the steel beam 16 is abutted against the outer surface of the steel pipe joint portion 12A and is welded or the like It is joined. On the other hand, a pair of upper and lower inner diaphragms 18 is provided on the inner side surface of the steel pipe joint 12A. Each inner diaphragm 18 is provided so as to be continuous with the flange portion 16 </ b> A of the steel beam 16, and the steel pipe joint 12 </ b> A is reinforced by the inner diaphragm 18. Further, a filling hole 18A (see FIG. 3) is formed at the center of each inner diaphragm 18, and the filled concrete 14 is filled into the steel pipe column 12 through these filling holes 18A.

ここで、鋼管本体部１２Ｂの４つの側壁の外側面１２Ｓ（図２（Ａ）参照）には、縦補剛リブ２２がそれぞれ設けられている。縦補剛リブ２２は平板状の鋼板で構成されており、その軸方向を柱軸方向（矢印Ｚ方向）にして配置され、鋼管本体部１２Ｂの略全長（柱軸方向の略全長）に渡って設けられている。即ち、縦補剛リブ２２は、鋼管本体部１２Ｂにおける軸方向端部としての鋼管上端部（柱頭部）１２ＢＵと鋼管下端部（柱脚部）１２ＢＬとに渡って設けられている。各縦補剛リブ２２は、図２（Ａ）及び図２（Ｂ）に示されるように、幅方向一端部２２Ａ（長手方向に沿った一端部側の端面）が鋼管本体部１２Ｂの外側面１２Ｓの柱幅方向（矢印Ｘ方向又は矢印Ｙ方向）の略中央部に突き当てられて溶接等により接合されている。これらの縦補剛リブ２２によって、鋼管本体部１２Ｂの各側壁に面外剛性が付与されている。   Here, longitudinal stiffening ribs 22 are provided on the outer side surfaces 12S (see FIG. 2A) of the four side walls of the steel pipe main body 12B. The longitudinal stiffening rib 22 is made of a flat steel plate, and is arranged with its axial direction as the column axis direction (arrow Z direction), and extends over the substantially entire length (substantially the entire length in the column axis direction) of the steel pipe body 12B. Is provided. That is, the vertical stiffening rib 22 is provided over the steel pipe upper end (column head) 12BU and the steel pipe lower end (column base) 12BL as axial ends of the steel pipe main body 12B. As shown in FIGS. 2A and 2B, each longitudinal stiffening rib 22 has one end 22A in the width direction (an end face on one end along the longitudinal direction) as an outer surface of the steel pipe main body 12B. It is abutted on the approximate center in the 12S column width direction (arrow X direction or arrow Y direction) and joined by welding or the like. By these vertical stiffening ribs 22, out-of-plane rigidity is imparted to each side wall of the steel pipe main body 12 </ b> B.

また、鋼管本体部１２Ｂの各外側面１２Ｓには、複数（本実施形態では、４枚）の断熱材２４が設けられている。断熱材２４は、ロックウール等をシート状に成形した巻き付けタイプの断熱材で形成されており、縦補剛リブ２２と鋼管柱１２の周方向（柱周方向）に隣接して配置されている。各断熱材２４は断面略Ｌ字形状に屈曲されると共に、その屈曲部が鋼管本体部１２Ｂのコーナー部（角部）に合わせられ、隣接する外側面１２Ｓにまたがって配置されている。これらの断熱材２４によって鋼管本体部１２Ｂの外側面１２Ｓが柱軸方向の略全長に渡って被覆されている。また、各断熱材２４は、柱周方向に隣接する縦補剛リブ２２の側面２２Ｃ間に渡って設けられている。これらの断熱材２４によって、縦補剛リブ２２の側面２２Ｃが柱軸方向の略全長に渡って被覆されている。なお、断熱材２４の厚さ（被覆厚）ｔ１（図２（Ｂ）参照）は、縦補剛リブ２２の幅ｔ２と略同じとされている。なお、本実施形態では、断熱材２４を４枚のL字形状に屈曲した断熱材で構成しているが、矩形に成形した８枚の断熱材、若しくはさらに分割した断熱材を用いても良い。 In addition, a plurality (four in this embodiment) of heat insulating materials 24 are provided on each outer surface 12S of the steel pipe main body 12B. The heat insulating material 24 is formed of a wrapping type heat insulating material obtained by forming rock wool or the like into a sheet shape, and is disposed adjacent to the circumferential direction (column circumferential direction) of the longitudinal stiffening rib 22 and the steel pipe column 12. . Each heat insulating material 24 is bent into a substantially L-shaped cross section, and the bent portion is aligned with the corner portion (corner portion) of the steel pipe main body portion 12B, and is disposed across the adjacent outer surface 12S. These heat insulating materials 24 cover the outer surface 12S of the steel pipe body 12B over substantially the entire length in the column axis direction. Moreover, each heat insulating material 24 is provided over the side surface 22C of the vertical stiffening rib 22 adjacent to the column circumferential direction. These heat insulating materials 24 cover the side surfaces 22C of the vertical stiffening ribs 22 over substantially the entire length in the column axis direction. Note that the thickness (covering thickness) t 1 (see FIG. 2B) of the heat insulating material 24 is substantially the same as the width t 2 of the longitudinal stiffening rib 22. In this embodiment, the heat insulating material 24 is composed of four heat insulating materials bent into an L shape, but eight heat insulating materials formed into a rectangular shape or further divided heat insulating materials may be used. .

鋼管本体部１２Ｂの外周には、断熱材２４を間において鋼管本体部１２Ｂの各外側面１２Ｓと対向する複数（本実施形態では、４枚）の仕上げ材２６が設けられている。各仕上げ材２６は、断面略Ｌ字形状に屈曲された薄鋼板で形成されており、その屈曲部を断熱材２４の屈曲部に合わせた状態で断熱材２４に重ねられている。また、柱周方向に隣接する仕上げ材２６は、各々の端部同士が縦補剛リブ２２の幅方向他端部２２Ｂ（長手方向に沿った他端部側の端面）の上で突き合わされ、当該幅方向他端部２２Ｂに溶接、接着剤等で接合されている。これらの仕上げ材２６によって、縦補剛リブ２２及び断熱材２４が略全長（柱軸方向の略全長）に渡って被覆されている。   A plurality (four in this embodiment) of finishing materials 26 are provided on the outer periphery of the steel pipe main body 12B so as to face each outer surface 12S of the steel pipe main body 12B with the heat insulating material 24 interposed therebetween. Each finishing material 26 is formed of a thin steel plate bent in a substantially L-shaped cross section, and is overlapped on the heat insulating material 24 in a state where the bent portion is matched with the bent portion of the heat insulating material 24. Further, the finishing material 26 adjacent in the column circumferential direction is abutted on the other end 22B in the width direction of the longitudinal stiffening rib 22 (the end surface on the other end side along the longitudinal direction) of the longitudinal stiffening ribs 22; The other end 22B in the width direction is joined by welding, an adhesive or the like. These finishing materials 26 cover the longitudinal stiffening ribs 22 and the heat insulating material 24 over substantially the entire length (substantially the entire length in the column axis direction).

なお、仕上げ材２６は、断熱材２４にピンや接着剤等やで固定しても良い。また、断熱材２４もピンや接着剤で鋼管本体部１２Ｂの外側面１２Ｓに固定しても良い。   The finishing material 26 may be fixed to the heat insulating material 24 with pins, an adhesive, or the like. Moreover, you may also fix the heat insulating material 24 to the outer surface 12S of the steel pipe main-body part 12B with a pin or an adhesive agent.

次に、第１実施形態に係る作用について説明する。   Next, the operation according to the first embodiment will be described.

図３に示されるように、例えば、火災時に鉄骨梁１６が熱膨張によって軸方向（水平方向）へ伸張すると、鋼管仕口部１２Ａに水平力Ｆが作用し、鋼管本体部１２Ｂに曲げモーメントＭが発生する。この曲げモーメントＭは、鋼管中間部１２ＢＭから鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに向って徐々に大きくなる。一方、鋼管柱１２は、火災時に熱膨張によって柱軸方向（矢印Ｚ方向）へ伸張するが、温度上昇に伴う剛性の低下によって柱軸方向への伸張は徐々に小さくなり、ある温度に達すると柱軸方向への伸張変形は止まり、収縮変形に転じる。この状態で、鉄骨梁１６から鋼管仕口部１２Ａへ水平力Ｆが作用すると、前述したように鋼管中間部１２ＢＭと比較して大きな曲げモーメントＭが発生する鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの圧縮側（矢印Ｃ側）の側壁に局部座屈Ｋが発生し易くなる。特に、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬが鋼管仕口部１２Ａを介して鉄骨梁１６に剛接合されていて、かつ、鉄骨梁１６の軸方向への伸張量が大きい場合は、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに大きな曲率を伴う変形が生じる。この変形によって鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの圧縮側（矢印Ｃ側）の側壁に大きな圧縮応力度が発生すると、当該側壁が面外方向外側へ変位する（はらみ出す）局部座屈Ｋが生じる。   As shown in FIG. 3, for example, when the steel beam 16 expands in the axial direction (horizontal direction) due to thermal expansion during a fire, a horizontal force F acts on the steel pipe joint 12A, and a bending moment M acts on the steel pipe main body 12B. Occurs. The bending moment M gradually increases from the steel pipe intermediate part 12BM toward the steel pipe upper end part 12BU and the steel pipe lower end part 12BL. On the other hand, the steel pipe column 12 expands in the column axis direction (arrow Z direction) due to thermal expansion in the event of a fire, but when the elongation in the column axis direction gradually decreases due to a decrease in rigidity accompanying a temperature rise, and reaches a certain temperature. The expansion deformation in the column axis direction stops and turns into contraction deformation. In this state, when a horizontal force F acts from the steel beam 16 to the steel pipe joint 12A, as described above, the steel pipe upper end 12BU and the steel pipe lower end 12BL generate a bending moment M larger than that of the steel pipe intermediate part 12BM. Local buckling K tends to occur on the side wall on the compression side (arrow C side). In particular, when the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL are rigidly joined to the steel beam 16 via the steel pipe connection portion 12A, and the steel beam 16 has a large extension in the axial direction, the steel pipe upper end portion A deformation | transformation with a big curvature arises in 12BU and steel pipe lower end part 12BL. When a large degree of compressive stress is generated on the compression side (arrow C side) side walls of the steel pipe upper end 12BU and the steel pipe lower end 12BL due to this deformation, the local buckling K that displaces (protrudes) outward in the out-of-plane direction is caused. Arise.

鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに局部座屈Ｋが発生すると、コンクリート充填鋼管柱１０の曲げ剛性は著しく低下する。コンクリート充填鋼管柱１０に作用する軸力（鉛直荷重）Ｖが大きい場合は、局部座屈Ｋの発生後、曲げモーメントＭによる変形が急激に進展し、局部座屈Ｋ側の充填コンクリート１４に圧壊を生じる。この結果、コンクリート充填鋼管柱１０は荷重支持能力を喪失し、脆性的に崩壊に至る場合がある。   When local buckling K occurs in the steel pipe upper end part 12BU and the steel pipe lower end part 12BL, the bending rigidity of the concrete-filled steel pipe column 10 is significantly reduced. When the axial force (vertical load) V acting on the concrete-filled steel pipe column 10 is large, after the occurrence of local buckling K, the deformation due to the bending moment M rapidly progresses and collapses to the filling concrete 14 on the local buckling K side. Produce. As a result, the concrete-filled steel pipe column 10 loses its load supporting ability and may collapse brittlely.

この対策として本実施形態では、鋼管本体部１２Ｂの各外側面１２Ｓが全長若しくは略全長に渡り縦補剛リブ２２で補強されている。これらの縦補剛リブ２２によって鋼管上端部１２ＢＵ、鋼管中間部１２ＢＭ及び鋼管下端部１２ＢＬの各側壁に面外剛性を付与することにより、当該側壁の面外方向外側への変位が抑制される。従って、前述した局部座屈Ｋの発生が抑制される。   As a countermeasure, in this embodiment, each outer surface 12S of the steel pipe main body 12B is reinforced by the longitudinal stiffening rib 22 over the entire length or substantially the entire length. By imparting out-of-plane rigidity to the side walls of the steel pipe upper end portion 12BU, the steel pipe intermediate portion 12BM, and the steel pipe lower end portion 12BL by the vertical stiffening ribs 22, displacement of the side walls in the out-of-plane direction is suppressed. Therefore, the occurrence of the local buckling K described above is suppressed.

また、本実施形態では、鋼管本体部１２Ｂの外側面１２Ｓが全長若しくは略全長に渡り断熱材２４で被覆されている。これにより、断熱材２４の熱吸収効果によって鋼管本体部１２Ｂの温度上昇が抑制されるため、温度上昇に伴う鋼管本体部１２Ｂの剛性の低下が抑制される。従って、前述した局部座屈Ｋの発生が抑制される。   In the present embodiment, the outer surface 12S of the steel pipe main body 12B is covered with the heat insulating material 24 over the entire length or substantially the entire length. Thereby, since the temperature rise of the steel pipe main-body part 12B is suppressed by the heat absorption effect of the heat insulating material 24, the fall of the rigidity of the steel pipe main-body part 12B accompanying a temperature rise is suppressed. Therefore, the occurrence of the local buckling K described above is suppressed.

更に、縦補剛リブ２２によって局部座屈Ｋの発生を抑制することにより、縦補剛リブ２２を備えない構成と比較して、断熱材２４の厚さｔ１（図２（Ｂ）参照）を薄くすることができる。従って、施工性の向上、コスト削減を図ることができる。また、図４（Ａ）に示されるように、柱周方向に隣接する縦補剛リブ２２の間に断熱材２４を設けたことにより、即ち、縦補剛リブ２２に隣接して断熱材２４を設けたことにより、縦補剛リブ２２が側面２２Ｃ側から加熱されることを防ぐと共に、断熱材２４の熱吸収容量によって鋼管本体部１２Ｂの温度上昇だけでなく、縦補剛リブ２２の温度上昇も抑制される。この結果、温度上昇に伴う縦補剛リブ２２の剛性低下が抑制される。従って、図４（Ｃ）に示される比較例のように断熱材２４及び仕上げ材２６を備えない構成と比較して、局部座屈Ｋに対する縦補剛リブ２２の抑制効果が長時間にわたり保持される。なお、図４（Ｃ）に示される縦補剛リブ２２は、矢印Ｎのように３方向から加熱される。 Further, by suppressing the occurrence of local buckling K by the vertical stiffening ribs 22, the thickness t 1 of the heat insulating material 24 compared to the configuration without the vertical stiffening ribs 22 (see FIG. 2B). Can be made thinner. Therefore, improvement in workability and cost reduction can be achieved. Further, as shown in FIG. 4A, the heat insulating material 24 is provided between the vertical stiffening ribs 22 adjacent in the column circumferential direction, that is, adjacent to the vertical stiffening ribs 22. The vertical stiffening rib 22 is prevented from being heated from the side surface 22C side, and the temperature of the vertical stiffening rib 22 is not only increased due to the heat absorption capacity of the heat insulating material 24, but also the temperature of the vertical stiffening rib 22 The rise is also suppressed. As a result, a decrease in the rigidity of the vertical stiffening rib 22 accompanying a temperature rise is suppressed. Therefore, as compared with the configuration in which the heat insulating material 24 and the finishing material 26 are not provided as in the comparative example shown in FIG. 4C, the effect of suppressing the vertical stiffening ribs 22 on the local buckling K is maintained for a long time. The The vertical stiffening rib 22 shown in FIG. 4C is heated from three directions as indicated by an arrow N.

特に、本実施形態では、断熱材２４によって縦補剛リブ２２の側面２２Ｃを被覆したことにより、図４（Ａ）に矢印ａで示されるように、縦補剛リブ２２に伝達された火災熱（矢印Ｎ）が断熱材２４へ伝達される。従って、断熱材２４によって縦補剛リブ２２の側面２２Ｃを被覆しない構成と比較して、縦補剛リブ２２の温度上昇が抑制される。   In particular, in the present embodiment, the side surface 22C of the vertical stiffening rib 22 is covered with the heat insulating material 24, so that the fire heat transmitted to the vertical stiffening rib 22 is indicated by an arrow a in FIG. (Arrow N) is transmitted to the heat insulating material 24. Therefore, the temperature rise of the vertical stiffening rib 22 is suppressed as compared with the configuration in which the side surface 22C of the vertical stiffening rib 22 is not covered by the heat insulating material 24.

このように本実施形態では、断熱材２４と縦補剛リブ２２との相乗効果により、鋼管本体部１２Ｂの局部座屈を抑制しつつ、断熱材２４の厚さｔ１（図２（Ｂ）参照）を薄くすることができる。 Thus, in the present embodiment, the thickness t 1 of the heat insulating material 24 (FIG. 2B) while suppressing local buckling of the steel pipe main body portion 12B due to the synergistic effect of the heat insulating material 24 and the longitudinal stiffening ribs 22. Can be made thinner.

また、本実施形態では、鋼管本体部１２Ｂの外周に仕上げ材２６が設けられている。仕上げ材２６は薄鋼板で構成されており、この仕上げ材２６によって断熱材２４及び縦補剛リブ２２が覆われている。従って、図４（Ａ）に示されるように、断熱材２４及び縦補剛リブ２２が火炎に直接曝されないため、これらの断熱材２４及び縦補剛リブ２２の温度上昇が抑制される。更には、矢印ｂで示されるように、仕上げ材２６を介して火災熱（矢印Ｎ）が断熱材２４に分散して伝達されるため、縦補剛リブ２２の温度上昇が更に抑制される。   Moreover, in this embodiment, the finishing material 26 is provided in the outer periphery of the steel pipe main-body part 12B. The finishing material 26 is made of a thin steel plate, and the heat insulating material 24 and the longitudinal stiffening ribs 22 are covered with the finishing material 26. Therefore, as shown in FIG. 4A, the heat insulating material 24 and the vertical stiffening ribs 22 are not directly exposed to the flame, so that the temperature rise of these heat insulating materials 24 and the vertical stiffening ribs 22 is suppressed. Furthermore, since the fire heat (arrow N) is distributed and transmitted to the heat insulating material 24 through the finishing material 26 as indicated by the arrow b, the temperature rise of the longitudinal stiffening ribs 22 is further suppressed.

ここで、図４（Ｂ）に示される変形例のように、仕上げ材２６は省略可能であるが、この場合、断熱材２４が火炎に直接曝されるため、断熱材２４に所定の耐火性能が求められる。例えば、ロックウールであれば、耐火性を有する高耐熱ロックウール等が好ましい。これに対して仕上げ材２６を備えた本実施形態では、図４（Ａ）に示されるように、断熱材２４として安価な断熱用のロックウールやグラスウール等を用いることができるため、断熱材２４のコスト削減を図ることができる。   Here, as in the modification shown in FIG. 4B, the finishing material 26 can be omitted, but in this case, since the heat insulating material 24 is directly exposed to the flame, the heat insulating material 24 has a predetermined fire resistance performance. Is required. For example, if it is rock wool, the high heat-resistant rock wool etc. which have fire resistance are preferable. On the other hand, in the present embodiment provided with the finishing material 26, as shown in FIG. 4A, inexpensive heat insulating rock wool, glass wool, or the like can be used as the heat insulating material 24. Cost reduction.

また、本実施形態では、仕上げ材２６が縦補剛リブ２２の幅方向他端部２２Ｂ（図２（Ａ）参照）に溶接等によって接合されている。即ち、縦補剛リブ２２は、仕上げ材２６を支持する支持部材としても機能する。これにより、図１５に示されるように、吹付けロックウール１２２で耐火被覆されたコンクリート充填鋼管柱１０の周囲に軽鉄スタッド１２４を立設し、これらの軽鉄スタッド１２４で仕上げ材１２６を支持する従来の仕上げ構造１２０と比較して、仕上げ材２６を含めた柱の水平断面積を小さくすることができる。従って、室内スペースを広げることができる。更に、コンクリート充填鋼管柱１０の周りに軽鉄スタッド１２４を立てる作業が不要になるため、従来の仕上げ構造と比較して施工性が向上する。   In the present embodiment, the finishing material 26 is joined to the other end 22B in the width direction of the vertical stiffening rib 22 (see FIG. 2A) by welding or the like. That is, the vertical stiffening rib 22 also functions as a support member that supports the finishing material 26. As a result, as shown in FIG. 15, light iron studs 124 are erected around the concrete-filled steel pipe columns 10 fire-resistant coated with spray rock wool 122 and the finishing material 126 is supported by these light iron studs 124. Compared with the conventional finishing structure 120, the horizontal sectional area of the column including the finishing material 26 can be reduced. Therefore, the indoor space can be expanded. Furthermore, since the operation | work which raises the light iron stud 124 around the concrete filling steel pipe column 10 becomes unnecessary, workability improves compared with the conventional finishing structure.

更に、本実施形態は、既存のコンクリート充填鋼管柱１０に対しても容易に適用することができる。例えば、竣工後の設計変更等により設計条件が変わり、コンクリート充填鋼管柱１０の耐火性能が不足する場合、具体的には、用途変更によって可燃物量が増えて火災継続時間が長くなる場合や、区画の変更によって区画面積が大きくなり、柱頭部に接合する鉄骨梁の熱膨張による伸張長さが増える場合、若しくは増築によって柱の負担軸力が大きくなる場合などでコンクリート充填鋼管柱１０の耐火性能が不足した場合に、後施工による耐火補強で既存のコンクリート充填鋼管柱１０の耐火性能を向上させたい場合に有効な方法である。   Furthermore, the present embodiment can be easily applied to the existing concrete-filled steel pipe column 10. For example, when the design conditions change due to a design change after completion and the fire resistance performance of the concrete-filled steel pipe column 10 is insufficient, specifically, when the amount of combustibles increases due to the change of use and the fire duration time becomes longer, When the extension area due to thermal expansion of the steel beam joined to the column head increases or the burden axial force of the column increases due to the extension, the fire resistance performance of the concrete-filled steel tube column 10 is increased. This is an effective method when it is desired to improve the fireproof performance of the existing concrete-filled steel pipe column 10 by fireproof reinforcement by post-construction when it is insufficient.

ここで、図５（Ａ）には、一般的なコンクリート充填鋼管柱からなる柱１００と梁１０２Ａ，１０２Ｂとで構成された架構の一例が示されている。この架構内において、例えば図５（Ｂ）に示されるように火災１０４が発生すると、梁１０２Ａが水平方向（矢印Ｊ方向）に伸び出すため、柱１００に同図に示されるような変形が生じる。   Here, FIG. 5A shows an example of a frame composed of a column 100 made of a general concrete-filled steel pipe column and beams 102A and 102B. In this frame, for example, when a fire 104 occurs as shown in FIG. 5B, the beam 102A extends in the horizontal direction (arrow J direction), so that the pillar 100 is deformed as shown in FIG. .

また、図６（Ａ）には、一般的なコンクリート充填鋼管柱からなる柱１１０の耐火性能評価に用いられる実験評価モデルが示されている。この実験評価モデルでは、加熱時に、図６（Ｂ）に示されるような変形状態、応力状態を示すことから、図５（Ｂ）に示される柱１００の変形状態、応力状態を適切に模擬することができると言われている。そこで、図６（Ａ）に示される実験評価モデルを用いて載荷加熱実験を行ったところ、以下に示す新たな知見が得られた。   FIG. 6 (A) shows an experimental evaluation model used for fire resistance performance evaluation of a column 110 made of a general concrete-filled steel pipe column. Since this experimental evaluation model shows the deformation state and the stress state as shown in FIG. 6B during heating, the deformation state and the stress state of the column 100 shown in FIG. 5B are appropriately simulated. It is said that you can. Then, when the loading heating experiment was conducted using the experimental evaluation model shown in FIG. 6 (A), the following new knowledge was obtained.

即ち、加熱された柱１１０の上端部に生じる水平変位（水平力Ｆ）が大きい場合や柱１１０に生じる軸力Ｖが大きい場合は、図６（Ｃ）に示されるように、柱１１０を構成する鋼管柱の上端部及び下端部に局部座屈Ｋが生じることが確認された。また、加熱時間が比較的短く、柱１１０の充填コンクリートが十分耐力を残している状態であっても、柱１１０は前述した鋼管柱の局部座屈Ｋによって荷重支持能力を喪失し、崩壊することが確認された。   That is, when the horizontal displacement (horizontal force F) generated at the upper end portion of the heated column 110 is large or when the axial force V generated at the column 110 is large, the column 110 is configured as shown in FIG. It was confirmed that local buckling K occurred at the upper end and the lower end of the steel pipe column. Moreover, even if the heating time is relatively short and the filled concrete of the column 110 remains sufficiently proof, the column 110 loses its load supporting ability due to the local buckling K of the steel pipe column and collapses. Was confirmed.

つまり、局部座屈Ｋに関しては以下のことが確認された。即ち、鋼管本体部１２Ｂの幅をＤ（図２（Ａ）参照）としたときに、鋼管上端部１２ＢＵにおける局部座屈Ｋは、その上端（鋼管仕口部１２Ａと鋼管本体部１２Ｂとの境界部）から２Ｄまでの領域内で発生し易く、特に、上端から１Ｄの領域内で発生し易い。これと同様に、鋼管下端部１２ＢＬにおける局部座屈Ｋは、その下端（鋼管仕口部１２Ａと鋼管本体部１２Ｂとの境界部）から２Ｄまでの領域内で発生し易く、特に、下端から１Ｄの領域内で発生し易い。   That is, the following was confirmed for the local buckling K. That is, when the width of the steel pipe main body 12B is D (see FIG. 2A), the local buckling K at the steel pipe upper end 12BU is the upper end (the boundary between the steel pipe fitting 12A and the steel pipe main body 12B). Part) to 2D, particularly in the 1D region from the upper end. Similarly, local buckling K in the steel pipe lower end portion 12BL is likely to occur in the region from the lower end (boundary portion between the steel pipe fitting portion 12A and the steel pipe main body portion 12B) to 2D, and in particular, 1D from the lower end. It is easy to occur in the area.

本実施形態では、鋼管本体部１２Ｂを全長にわたり縦補剛リブ２２及び断熱材２４で補強したが、局部座屈Ｋの発生を抑制する観点からすると、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬのみに縦補剛リブ２２及び断熱材２４が設けられていれば良く、鋼管中間部１２ＢＭにおける縦補剛リブ２２及び断熱材２４は省略しても良い。この場合、鋼管上端部１２ＢＵでは、例えば、縦補剛リブ２２及び断熱材２４を鋼管上端部１２ＢＵの上端から鋼管中間部１２ＢＭへ向けて１Ｄ以上の範囲に設けることが好ましく、２Ｄ以上の範囲に設けることがより好ましい。これと同様に、鋼管下端部１２ＢＬでは、縦補剛リブ２２及び断熱材２４を鋼管下端部１２ＢＬの下端から鋼管中間部１２ＢＭへ向けて少なくとも１Ｄ以上の範囲に設けることが好ましく、２Ｄ以上の範囲に設けることがより好ましい。これにより、縦補剛リブ２２及び断熱材２４の材料コストを削減しつつ、鋼管上端部１２ＢＵの局部座屈Ｋの発生を効率的に抑制することができる。鋼管下端部１２ＢＬについても同様である。   In the present embodiment, the steel pipe body 12B is reinforced with the longitudinal stiffening ribs 22 and the heat insulating material 24 over the entire length. However, from the viewpoint of suppressing the occurrence of local buckling K, only the steel pipe upper end 12BU and the steel pipe lower end 12BL are provided. The longitudinal stiffening rib 22 and the heat insulating material 24 may be provided, and the vertical stiffening rib 22 and the heat insulating material 24 in the steel pipe intermediate portion 12BM may be omitted. In this case, in the steel pipe upper end portion 12BU, for example, the longitudinal stiffening rib 22 and the heat insulating material 24 are preferably provided in a range of 1D or more from the upper end of the steel pipe upper end portion 12BU toward the steel pipe intermediate portion 12BM. More preferably. Similarly, in the steel pipe lower end portion 12BL, it is preferable to provide the vertical stiffening rib 22 and the heat insulating material 24 in the range of at least 1D from the lower end of the steel pipe lower end portion 12BL toward the steel pipe intermediate portion 12BM. More preferably. Thereby, generation | occurrence | production of the local buckling K of the steel pipe upper end part 12BU can be suppressed efficiently, reducing the material cost of the vertical stiffening rib 22 and the heat insulating material 24. FIG. The same applies to the lower end 12BL of the steel pipe.

なお、設計条件が厳しい場合、例えば鋼管仕口部１２Ａに接合される鉄骨梁１６の熱膨張による伸張長さが大きい場合や鋼管本体部１２Ｂの負担する軸力が大きい場合などで、補強範囲を鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬのみに限定した場合、剛性の極端な変化によって、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬと鋼管中間部１２ＢＭの境界面付近で局部座屈が発生し、これによって鋼管本体部１２Ｂが破壊する可能性がある。鋼管本体部１２Ｂの軸方向にわたる剛性の極端な変化をさけるため、縦補剛リブ２２を鋼管本体部１２Ｂの全長にわたり設置して、断熱材２４を鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬのみに設置しても良い。逆に、縦補剛リブ２２は鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬのみに設置して、断熱材２４は鋼管本体部１２Ｂの全長にわたり設置しても良い。   In addition, when design conditions are severe, for example, when the extension length due to thermal expansion of the steel beam 16 joined to the steel pipe joint portion 12A is large or when the axial force borne by the steel pipe main body portion 12B is large, the reinforcement range is set. When limited to only the steel pipe upper end 12BU and the steel pipe lower end 12BL, local buckling occurs in the vicinity of the boundary surface between the steel pipe upper end 12BU and the steel pipe lower end 12BL and the steel pipe intermediate portion 12BM due to an extreme change in rigidity. There is a possibility that the steel pipe body 12B will be destroyed. In order to avoid an extreme change in the rigidity of the steel pipe body 12B in the axial direction, the longitudinal stiffening rib 22 is installed over the entire length of the steel pipe body 12B, and the heat insulating material 24 is installed only in the steel pipe upper end 12BU and the steel pipe lower end 12BL. You may do it. Conversely, the longitudinal stiffening ribs 22 may be installed only on the steel pipe upper end 12BU and the steel pipe lower end 12BL, and the heat insulating material 24 may be installed over the entire length of the steel pipe main body 12B.

なお、前述した局部座屈Ｋによる破壊はこれまでの実験では確認されなかった現象である。これまでの実験では、柱１１０の断面を小断面（例えば、３００ｍｍ×３００ｍｍ程度）で実施していたが、前述した局部座屈Ｋが確認された実験では、柱１１０の断面を大面積（６００ｍｍ×６００ｍｍ）で実施している。柱頭、柱脚に生じる曲率が同じ場合、鋼管柱の上端部及び下端部に発生する圧縮ひずみは、柱１１０の中立軸位置から鋼管柱までの距離に比例して大きくなる。断面が大きくなれば、鋼管柱の側壁に生じる圧縮ひずみもこれに比例して大きくなる。このため、火災によって大断面の柱（例えば、６００ｍｍ×６００ｍｍ以上）の上端部に大きな水平力が生じると、柱の上端部及び下端部には大きな圧縮ひずみが発生する。前述の実験では、鋼管柱に生じた圧縮ひずみが当該鋼管柱の局部座屈に対する許容圧縮ひずみを超過したために発生したものと考えられる。この圧縮ひずみは、長期軸力に起因する長期圧縮ひずみε１と、梁の伸長に伴う強制変形（水平力Ｆ）に起因する圧縮ひずみε２と、同梁の伸長に伴う付加曲げモーメントに起因する圧縮ひずみε３の和と考えることも可能である。   Note that the above-described destruction due to local buckling K is a phenomenon that has not been confirmed in previous experiments. In the previous experiments, the cross section of the pillar 110 was implemented with a small cross section (for example, about 300 mm × 300 mm). However, in the experiment in which the local buckling K described above was confirmed, the cross section of the pillar 110 was large in area (600 mm). × 600 mm). When the curvature generated in the column head and the column base is the same, the compressive strain generated in the upper end portion and the lower end portion of the steel pipe column increases in proportion to the distance from the neutral axis position of the column 110 to the steel tube column. If the cross section becomes large, the compressive strain generated on the side wall of the steel pipe column also increases in proportion thereto. For this reason, when a large horizontal force is generated at the upper end portion of a large cross-sectional column (for example, 600 mm × 600 mm or more) due to a fire, a large compressive strain is generated at the upper end portion and the lower end portion of the column. In the above-described experiment, it is considered that the compressive strain generated in the steel pipe column exceeded the allowable compressive strain for local buckling of the steel pipe column. This compressive strain includes a long-term compressive strain ε1 caused by a long-term axial force, a compressive strain ε2 caused by a forced deformation (horizontal force F) accompanying the extension of the beam, and a compression caused by an additional bending moment accompanying the extension of the beam. It can also be considered as the sum of strains ε3.

なお、本実施形態のように鋼管仕口部１２Ａの両側に鉄骨梁１６が接合された構成では、各鉄骨梁１６の伸長に伴って鋼管仕口部１２Ａの両側に反対向きの水平力が作用するため、これらの水平力が打ち消し合う。従って、前述した圧縮ひずみε２，ε３が小さくなり易い。一方、建物の外周に配置される側柱又は隅柱のように、鋼管仕口部１２Ａの片側（水平方向片側）にのみ鉄骨梁１６が接合される構成では、上記圧縮ひずみε２，ε３が大きくなり易い。特に、鋼管仕口部１２Ａの片側に接合される鉄骨梁１６の梁スパンが長くなると（例えば、１０ｍ程度以上）、火災時における鉄骨梁１６の伸長量が増加し、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの水平変位（強制変形）が大きくなるため（例えば、柱の部材角１／５０ｒａｄ程度）、上記圧縮ひずみε２，ε３が過大となる可能性がある。本実施形態は、このように鋼管仕口部１２Ａの片側に鉄骨梁１６が接合されるコンクリート充填鋼管柱１０の耐火補強に適している。   In the configuration in which the steel beam 16 is joined to both sides of the steel pipe joint 12A as in the present embodiment, the opposite horizontal force acts on both sides of the steel pipe joint 12A as each steel beam 16 extends. Therefore, these horizontal forces cancel each other. Therefore, the above-described compression strains ε2, ε3 tend to be small. On the other hand, in the configuration in which the steel beam 16 is joined only to one side (one side in the horizontal direction) of the steel pipe joint portion 12A such as a side column or a corner column arranged on the outer periphery of the building, the compression strains ε2 and ε3 are large. It is easy to become. In particular, when the beam span of the steel beam 16 joined to one side of the steel pipe joint 12A becomes long (for example, about 10 m or more), the extension amount of the steel beam 16 at the time of fire increases, and the steel pipe upper end 12BU and the steel pipe lower end Since the horizontal displacement (forced deformation) of the portion 12BL becomes large (for example, the column member angle is about 1/50 rad), the compressive strains ε2 and ε3 may be excessive. The present embodiment is suitable for fireproof reinforcement of the concrete-filled steel pipe column 10 in which the steel beam 16 is joined to one side of the steel pipe joint 12A.

次に、第２実施形態について説明する。なお、第１実施形態と同様の構成のものについては、同符号を付すると共に適宜省略して説明する。   Next, a second embodiment will be described. In addition, about the thing of the structure similar to 1st Embodiment, it attaches | subjects the same code | symbol and abbreviate | omits suitably, and demonstrates.

図７及び図８には、第２実施形態に係る耐火補強構造３０が適用されたコンクリート充填鋼管柱１０が示されている。第２実施形態では、鋼管本体部１２Ｂの外側面１２Ｓ（図８参照）に、補剛リブとしての複数（本実施形態では、３つ）の環状補剛リブ３２が設けられている。これらの環状補剛リブ３２は柱軸方向に間隔を空けて配置され、鋼管上端部１２ＢＵ、鋼管中間部１２ＢＭ、及び鋼管下端部１２ＢＬにそれぞれ設けられている。   7 and 8 show the concrete-filled steel pipe column 10 to which the fireproof reinforcing structure 30 according to the second embodiment is applied. In the second embodiment, a plurality (three in this embodiment) of annular stiffening ribs 32 as stiffening ribs are provided on the outer surface 12S (see FIG. 8) of the steel pipe body 12B. These annular stiffening ribs 32 are arranged at intervals in the column axis direction, and are respectively provided on the steel pipe upper end portion 12BU, the steel pipe intermediate portion 12BM, and the steel pipe lower end portion 12BL.

図８に示されるように、環状補剛リブ３２は、平面視にて略矩形のリング状の鋼板で形成されており、鋼管本体部１２Ｂの外周に柱周方向に沿って配置され、当該鋼管本体部１２Ｂを囲んでいる。この環状補剛リブ３２の内周部３２Ａは、鋼管本体部１２Ｂの外側面１２Ｓに溶接等により接合されている。この環状補剛リブ３２によって、鋼管本体部１２Ｂの各側壁に面外剛性が付与されている。   As shown in FIG. 8, the annular stiffening rib 32 is formed of a substantially rectangular ring-shaped steel plate in plan view, and is disposed along the column circumferential direction on the outer periphery of the steel pipe main body portion 12 </ b> B. The main body 12B is enclosed. The inner peripheral portion 32A of the annular stiffening rib 32 is joined to the outer surface 12S of the steel pipe main body portion 12B by welding or the like. By this annular stiffening rib 32, out-of-plane rigidity is imparted to each side wall of the steel pipe body 12B.

また、鋼管本体部１２Ｂの外側面１２Ｓには、環状補剛リブ３２と柱軸方向に隣接する複数の断熱材２４が設けられている。断熱材２４は、環状補剛リブ３２の柱軸方向両側に設けられ、鋼管本体部１２Ｂに巻き付けられている。これらの断熱材２４によって、鋼管本体部１２Ｂの外側面１２Ｓが被覆されている。また、各断熱材２４は、環状補剛リブ３２の側面３２Ｂに沿って設けられている。これらの断熱材２４によって環状補剛リブ３２の側面３２Ｂが被覆されている。なお、断熱材２４の厚さ（被覆厚）ｔ１は、環状補剛リブ３２の幅ｔ３と略同じとされている。 Moreover, the outer surface 12S of the steel pipe main body part 12B is provided with a plurality of heat insulating materials 24 adjacent to the annular stiffening rib 32 in the column axis direction. The heat insulating material 24 is provided on both sides of the annular stiffening rib 32 in the column axis direction, and is wound around the steel pipe body 12B. These heat insulating materials 24 cover the outer surface 12S of the steel pipe body 12B. Each heat insulating material 24 is provided along the side surface 32 </ b> B of the annular stiffening rib 32. The side surfaces 32B of the annular stiffening rib 32 are covered with these heat insulating materials 24. The thickness (covering thickness) t 1 of the heat insulating material 24 is substantially the same as the width t 3 of the annular stiffening rib 32.

また、鋼管本体部１２Ｂの外周には、断熱材２４を間において鋼管本体部１２Ｂの各外側面１２Ｓと対向する複数（本実施形態では、４枚）の仕上げ材２６が設けられている。各仕上げ材２６は平板状の薄鋼板で形成されており、断熱材２４及び環状補剛リブ３２の上に重ねられると共に、ピン又は接着剤等により断熱材２４に固定され、鋼管本体部１２Ｂを囲んでいる。これらの仕上げ材２６によって、縦補剛リブ２２及び断熱材２４が略全長（柱軸方向の略全長）に渡って被覆されている。   In addition, a plurality (four in this embodiment) of finishing materials 26 are provided on the outer periphery of the steel pipe main body 12B so as to face each outer surface 12S of the steel pipe main body 12B with the heat insulating material 24 interposed therebetween. Each finishing material 26 is formed of a flat thin steel plate, is overlaid on the heat insulating material 24 and the annular stiffening rib 32, and is fixed to the heat insulating material 24 with a pin or an adhesive, etc. Surrounding. These finishing materials 26 cover the longitudinal stiffening ribs 22 and the heat insulating material 24 over substantially the entire length (substantially the entire length in the column axis direction).

なお、仕上げ材２６は、環状補剛リブ３２の外周部に溶接、接着剤等で接合しても良い。また、第１実施形態と同様に、仕上げ材２６は省略可能であるが、この場合、断熱材２４が火炎に直接曝されるため、断熱材２４に所定の耐火性能が求められる。例えば、ロックウールであれば、耐火性を有する高耐熱ロックウール等が好ましい。これに対して仕上げ材２６を備えた本実施形態では、断熱材２４として安価な断熱用のロックウールやグラスウール等を用いることができるため、断熱材２４のコスト削減を図ることができる。   The finishing material 26 may be joined to the outer peripheral portion of the annular stiffening rib 32 by welding, an adhesive, or the like. Further, as in the first embodiment, the finishing material 26 can be omitted, but in this case, since the heat insulating material 24 is directly exposed to the flame, the heat insulating material 24 is required to have a predetermined fire resistance. For example, if it is rock wool, the high heat-resistant rock wool etc. which have fire resistance are preferable. On the other hand, in this embodiment provided with the finishing material 26, since the cheap heat insulating rock wool, glass wool, or the like can be used as the heat insulating material 24, the cost of the heat insulating material 24 can be reduced.

また、図８に示す実施形態では、環状補剛リブ３２は、平面視にて略矩形のリング状の鋼板で形成されると共に鋼管本体部１２Ｂの外周に柱周方向に沿って当該鋼管本体部１２Ｂを囲むように配置され、その内周部３２Ａを鋼管本体部１２Ｂの外側面１２Ｓに溶接されているが、図９に示すように、環状補剛リブ３２の内周部３２Ａに環状補剛リブ凸部３２Ｔを設け、環状補剛リブ凸部３２Ｔと鋼管本体部１２Ｂの外側面１２Ｓを溶接により接合しても良い。これにより溶接箇所が少なくなり、特に、鋼管本体部１２Ｂのコーナー部における溶接が不要となるため、施工性が向上する。図９に示すように、コーナー部を曲げ加工して成形された角形鋼管からなる鋼管柱１２の場合は特に有効である。   Further, in the embodiment shown in FIG. 8, the annular stiffening rib 32 is formed of a substantially rectangular ring-shaped steel plate in plan view, and the steel pipe main body portion along the column circumferential direction on the outer periphery of the steel pipe main body portion 12B. The inner peripheral portion 32A is disposed so as to surround 12B, and the inner peripheral portion 32A is welded to the outer surface 12S of the steel pipe main body portion 12B. However, as shown in FIG. The rib convex portion 32T may be provided, and the annular stiffening rib convex portion 32T and the outer surface 12S of the steel pipe main body portion 12B may be joined by welding. As a result, the number of welded portions is reduced, and in particular, welding at the corner portion of the steel pipe main body portion 12B becomes unnecessary, so that workability is improved. As shown in FIG. 9, the case of a steel pipe column 12 made of a square steel pipe formed by bending a corner portion is particularly effective.

なお、図９では環状補剛リブ３２の一面につき環状補剛リブ凸部３２Ｔが２箇所設けられているが、環状補剛リブ凸部３２Ｔをさらに増やしても良いし、逆に環状補剛リブ凸部３２Ｔを１箇所にしてもよい。環状補剛リブ凸部３２Ｔを１箇所にする場合は、環状補剛リブ凸部３２Ｔの幅を広げることが好ましい。   In FIG. 9, two annular stiffening rib convex portions 32T are provided on one surface of the annular stiffening rib 32. However, the annular stiffening rib convex portion 32T may be further increased. You may make the convex part 32T in one place. When the annular stiffening rib convex portion 32T is provided at one place, it is preferable to widen the annular stiffening rib convex portion 32T.

次に、第２実施形態の作用について説明する。   Next, the operation of the second embodiment will be described.

図８及び図１０（Ａ）に示されるように、鋼管本体部１２Ｂの外周には、柱周方向に沿って配置された複数の環状補剛リブ３２が設けられており、これらの環状補剛リブ３２によって鋼管本体部１２Ｂの各側壁に面外剛性が付与されている。従って、鋼管本体部１２Ｂの各側壁の局部座屈が抑制される。   As shown in FIG. 8 and FIG. 10 (A), a plurality of annular stiffening ribs 32 arranged along the circumferential direction of the column are provided on the outer periphery of the steel pipe main body 12B. Out-of-plane rigidity is given to each side wall of the steel pipe body 12B by the ribs 32. Therefore, local buckling of each side wall of the steel pipe body 12B is suppressed.

また、鋼管本体部１２Ｂの局部座屈は、前述したように鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬにおいて発生し易いところ、本実施形態では、図７及び図１０（Ａ）に示されるように鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの外側面１２Ｓに環状補剛リブ３２がそれぞれ設けられている。従って、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの側壁の局部座屈Ｋ（図３参照）の発生が抑制される。   Further, as described above, local buckling of the steel pipe main body 12B is likely to occur in the steel pipe upper end 12BU and the steel pipe lower end 12BL. In this embodiment, as shown in FIGS. 7 and 10A, the steel pipe An annular stiffening rib 32 is provided on the outer surface 12S of the upper end 12BU and the steel pipe lower end 12BL. Therefore, generation | occurrence | production of the local buckling K (refer FIG. 3) of the side wall of steel pipe upper end part 12BU and steel pipe lower end part 12BL is suppressed.

また、環状補剛リブ３２によって鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬを囲んだことにより、これらの鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの側壁の面外方向外側への変位に対して環状補剛リブ３２がその周方向軸力で抵抗するコンファインド効果を発揮する。従って、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの側壁の局部座屈Ｋに対する抑制効果が向上する。   Further, by enclosing the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL by the annular stiffening rib 32, the annular stiffening is prevented against the outward displacement of the side walls of the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL. The rib 32 exhibits a confining effect that resists with its circumferential axial force. Therefore, the suppression effect with respect to the local buckling K of the side wall of steel pipe upper end part 12BU and steel pipe lower end part 12BL improves.

更に、環状補剛リブ３２は柱周方向に沿って配置されている。これにより、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの側壁に曲げ剛性を付与せずに、若しくはその付与量を小さく抑えつつ、これらの側壁に面外剛性を付与することができる。つまり、環状補剛リブ３２付近で鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの曲げ剛性を急激に変化させずに、これらの鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの側壁に面外剛性を付与することができる。これにより、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬにおける環状補剛リブ３２付近で曲げ剛性が急激に変化しないため、当該環状補剛リブ３２付近に対する応力集中が低減される。従って、前述したように鋼管中間部１２ＢＭと比較して大きな曲げモーメントＭ（図３参照）が発生する鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに局部座屈Ｋが発生し易くなる。即ち、局部座屈Ｋが発生する部位を鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに限定することができる。従って、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬの局部座屈Ｋを効率的に抑制することができる。   Further, the annular stiffening rib 32 is arranged along the column circumferential direction. Thereby, out-of-plane rigidity can be given to these side walls, without giving bending rigidity to the side wall of steel pipe upper end part 12BU and steel pipe lower end part 12BL, or suppressing the amount of provision small. That is, the out-of-plane rigidity is imparted to the side walls of the steel pipe upper end 12BU and the steel pipe lower end 12BL without abruptly changing the bending rigidity of the steel pipe upper end 12BU and the steel pipe lower end 12BL in the vicinity of the annular stiffening rib 32. Can do. Thereby, since bending rigidity does not change abruptly in the vicinity of the annular stiffening rib 32 in the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL, stress concentration on the vicinity of the annular stiffening rib 32 is reduced. Accordingly, as described above, local buckling K is likely to occur in the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL where a large bending moment M (see FIG. 3) is generated as compared with the steel pipe intermediate portion 12BM. That is, the part where the local buckling K occurs can be limited to the steel pipe upper end part 12BU and the steel pipe lower end part 12BL. Therefore, the local buckling K of the steel pipe upper end part 12BU and the steel pipe lower end part 12BL can be efficiently suppressed.

また、前述したように、鋼管上端部１２ＢＵでは、その上端（鋼管仕口部１２Ａと鋼管本体部１２Ｂとの境界部）から２Ｄまでの領域内で局部座屈Ｋ（図３参照）が発生し易く、特に、上端から０．５Ｄ〜１Ｄの領域内で発生し易い。従って、局部座屈Ｋの発生を抑制する観点からすると、図１０（Ｂ）に示すように、鋼管上端部１２ＢＵの上端から０．５Ｄ〜１Ｄの範囲、及び、鋼管下端部１２ＢＬの下端から０．５Ｄ〜１Ｄの範囲に環状補剛リブ３２を一箇所ずつ配置する方法が最も合理的な形態である。   Further, as described above, in the steel pipe upper end portion 12BU, local buckling K (see FIG. 3) occurs in the region from the upper end (the boundary portion between the steel pipe fitting portion 12A and the steel pipe main body portion 12B) to 2D. It is easy to generate in the region of 0.5D to 1D from the upper end. Therefore, from the viewpoint of suppressing the occurrence of local buckling K, as shown in FIG. 10 (B), the range from 0.5D to 1D from the upper end of the steel pipe upper end portion 12BU and 0 from the lower end of the steel pipe lower end portion 12BL. A method in which the annular stiffening ribs 32 are arranged one by one in the range of 5D to 1D is the most rational form.

なお、環状補剛リブ３２は仕上げ材２６の下地材としての機能も兼ねているため、下地材の効果的な配置という観点から前述の第２実施形態では、鋼管上端部１２ＢＵ、鋼管中間部１２ＢＭ、及び鋼管下端部１２ＢＬに各一箇所ずつ、計３枚の環状補剛リブ３２を設置した。仕上げ材２６を設置しない場合、あるいは、仕上げ材２６の剛性が十分あり、環状補剛リブ３２が上下２箇所であっても仕上げ材２６の設置が可能な場合は、鋼管上端部１２ＢＵの上端から０．５Ｄ〜１Ｄの範囲、及び、鋼管下端部１２ＢＬの下端から０．５Ｄ〜１Ｄの範囲に環状補剛リブ３２を一箇所ずつ配置することで、コストの削減を図ることができる。   Since the annular stiffening rib 32 also serves as a base material for the finishing material 26, the steel pipe upper end portion 12BU and the steel pipe intermediate portion 12BM are used in the second embodiment described above from the viewpoint of effective placement of the base material. A total of three annular stiffening ribs 32 were installed at each of the steel pipe lower ends 12BL. When the finishing material 26 is not installed, or when the finishing material 26 is sufficiently rigid and the finishing material 26 can be installed even when the annular stiffening ribs 32 are located at two locations, the upper end of the steel pipe upper end portion 12BU. By arranging the annular stiffening ribs 32 one by one in the range of 0.5D to 1D and the range of 0.5D to 1D from the lower end of the steel pipe lower end portion 12BL, the cost can be reduced.

また、設計条件が厳しい場合、例えば柱頭部に接合する梁の熱膨張による伸張長さが大きい場合や柱の負担する軸力が大きい場合などで、環状補剛リブ３２を図１０（Ａ）や図１０（Ｂ）に示す方法で配置するだけでは、局部座屈Ｋの発生を抑制できない場合、あるいは、鋼管が薄くて細かい局部座屈Ｋが鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに多数発生するような場合などは、環状補剛リブ３２を複数枚配置すると良い。   Further, when the design conditions are severe, for example, when the extension length due to thermal expansion of the beam joined to the column head is large or when the axial force imposed by the column is large, the annular stiffening rib 32 is formed as shown in FIG. If the generation of local buckling K cannot be suppressed only by arranging by the method shown in FIG. 10B, or the steel pipe is thin and fine, local buckling K occurs in a large number in the steel pipe upper end 12BU and the steel pipe lower end 12BL. In such a case, a plurality of annular stiffening ribs 32 may be arranged.

効果的な配置の一例として、図１１（Ａ）では鋼管上端部１２ＢＵの上端から０．５Ｄ付近と１Ｄ付近の位置に一箇所ずつ、鋼管下端部１２ＢＬの下端から０．５Ｄ付近と１Ｄ付近の位置に一箇所ずつ環状補剛リブ３２を配置した場合を示す。また、効果的な配置の他の例として、図１１（Ｂ）では、鋼管上端部１２ＢＵの上端から０．５Ｄ付近と１Ｄ付近と１．５Ｄ付近の位置に一箇所ずつ、鋼管下端部１２ＢＬの下端から０．５Ｄ付近と１Ｄ付近と１．５Ｄ付近の位置に一箇所ずつ環状補剛リブ３２を配置した場合を示す。   As an example of an effective arrangement, in FIG. 11 (A), one point is located near 0.5D and 1D from the upper end of the steel pipe upper end 12BU, and 0.5D and 1D from the lower end of the steel pipe lower end 12BL. The case where the cyclic | annular stiffening rib 32 is arrange | positioned 1 each at a position is shown. Further, as another example of the effective arrangement, in FIG. 11B, the steel pipe lower end 12BL is placed at positions of 0.5D, 1D and 1.5D, respectively, from the upper end of the steel pipe upper end 12BU. The case where the cyclic | annular stiffening rib 32 is arrange | positioned one each in the position of 0.5D vicinity, 1D vicinity, and 1.5D vicinity from a lower end is shown.

次に、第１，第２実施形態の変形例について説明する。   Next, modified examples of the first and second embodiments will be described.

上記第１，第２実施形態では、鋼管本体部１２Ｂの外側面１２Ｓの略全面を断熱材２４で被覆したがこれに限らない。断熱材２４はコンクリート充填鋼管柱１０に求められる耐火性能に応じて適宜設ければ良い。第１実施形態を例に具体的に説明すると、図１２（Ａ）に示されるように、平断面視にて鋼管本体部１２Ｂの周囲に部分的に断熱材４４を設け、柱周方向に隣接する断熱材４４の間に隙間４６を形成しても良い。また、図１２（Ｂ）に示されるように、縦補剛リブ２２の側面２２Ｃと断熱材２４との間に隙間４６を形成しても良い。つまり、図１２（Ｂ）に示される変形例では、断熱材２４によって縦補剛リブ２２の側面２２Ｃが被覆されていない。このように鋼管本体部１２Ｂの周囲に断熱材２４がない隙間４６を形成しても、断熱材２４の熱吸収容量によって縦補剛リブ２２及び鋼管本体部１２Ｂの温度上昇を抑制することができる。第２実施形態についても同様である。   In the said 1st, 2nd embodiment, although the substantially whole surface of the outer surface 12S of the steel pipe main-body part 12B was coat | covered with the heat insulating material 24, it is not restricted to this. The heat insulating material 24 may be appropriately provided according to the fire resistance required for the concrete-filled steel pipe column 10. Specifically, taking the first embodiment as an example, as shown in FIG. 12 (A), a heat insulating material 44 is partially provided around the steel pipe main body 12B in a plan view, and adjacent to the column circumferential direction. You may form the clearance gap 46 between the heat insulating materials 44 to perform. Further, as shown in FIG. 12B, a gap 46 may be formed between the side surface 22 </ b> C of the vertical stiffening rib 22 and the heat insulating material 24. That is, in the modification shown in FIG. 12B, the side surface 22 </ b> C of the vertical stiffening rib 22 is not covered with the heat insulating material 24. Thus, even if the clearance 46 without the heat insulating material 24 is formed around the steel pipe main body 12B, the temperature increase of the longitudinal stiffening rib 22 and the steel pipe main body 12B can be suppressed by the heat absorption capacity of the heat insulating material 24. . The same applies to the second embodiment.

また、上記第１，第２実施形態における縦補剛リブ２２及び環状補剛リブ３２の形状は適宜変更可能である。縦補剛リブとしては、例えば、Ｌ形鋼、Ｔ形鋼、Ｃ形鋼、Ｈ形鋼、Ｉ形鋼等を用いることができる。また、環状補剛リブは、例えば、Ｌ形鋼、Ｔ形鋼、Ｃ形鋼、Ｈ形鋼、Ｉ形鋼等を環状に連結して構成しても良い。また、環状補剛リブ３２ではなく、柱幅方向に延びる棒状の横補剛リブを鋼管本体部１２Ｂの各外側面１２Ｓに設けても良い。   Further, the shapes of the longitudinal stiffening rib 22 and the annular stiffening rib 32 in the first and second embodiments can be changed as appropriate. As the vertical stiffening rib, for example, L-shaped steel, T-shaped steel, C-shaped steel, H-shaped steel, I-shaped steel or the like can be used. In addition, the annular stiffening rib may be configured by connecting, for example, an L-shaped steel, a T-shaped steel, a C-shaped steel, an H-shaped steel, an I-shaped steel or the like in an annular shape. Further, instead of the annular stiffening rib 32, a rod-shaped lateral stiffening rib extending in the column width direction may be provided on each outer surface 12S of the steel pipe main body 12B.

更に、上記第１，第２実施形態における縦補剛リブ２２及び環状補剛リブ３２の数や配置は適宜変更可能である。第１実施形態を例に具体的に説明すると、上記第１実施形態では、図１に示されるように、縦補剛リブ２２を鋼管本体部１２Ｂの略全長（柱軸方向の略全長）に渡って設けたが、複数の縦補剛リブ２２を柱軸方向に間隔を空けて設けも良い。また、図１３に示される変形例のように鋼管本体部１２Ｂの１つの外側面１２Ｓに対して複数の縦補剛リブ２２を設けても良い。更に、複数の縦補剛リブ２２を略全長に渡り設けても良いし、一部は略全長にわたり設けて、残りは柱軸方向へ部分的に設けても良い。ただし、前述したように局部座屈Ｋ（図３参照）は鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに発生し易い。従って、縦補剛リブ２２は鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに設けることが好ましい。また、環状補剛リブ３２を複数配置する場合も、鋼管上端部１２ＢＵ及び鋼管下端部１２ＢＬに設けることが好ましい。   Furthermore, the number and arrangement of the longitudinal stiffening ribs 22 and the annular stiffening ribs 32 in the first and second embodiments can be appropriately changed. Specifically, taking the first embodiment as an example, in the first embodiment, as shown in FIG. 1, the vertical stiffening ribs 22 are made substantially the entire length (substantially the entire length in the column axis direction) of the steel pipe body 12B. However, a plurality of longitudinal stiffening ribs 22 may be provided at intervals in the column axis direction. Moreover, you may provide several vertical stiffening rib 22 with respect to one outer side surface 12S of the steel pipe main-body part 12B like the modification shown by FIG. Further, a plurality of vertical stiffening ribs 22 may be provided over substantially the entire length, some may be provided over substantially the entire length, and the remaining may be provided partially in the column axis direction. However, as described above, local buckling K (see FIG. 3) is likely to occur in the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL. Therefore, the vertical stiffening ribs 22 are preferably provided on the steel pipe upper end 12BU and the steel pipe lower end 12BL. Further, when a plurality of annular stiffening ribs 32 are arranged, it is preferable to provide the steel pipe upper end portion 12BU and the steel pipe lower end portion 12BL.

更にまた、上記第２実施形態では、鋼管本体部１２Ｂの外側面１２Ｓに環状補剛リブ３２を溶接（連続溶接）等で接合したがこれに限らない。例えば、鋼管本体部１２Ｂの側壁に曲げ剛性が付与されないように、鋼管本体部１２Ｂの外側面１２Ｓに環状補剛リブ３２を断続溶接で接合しても良いし、接合金物等のスペーサを介して、鋼管本体部１２Ｂの側壁との間に隙間を空けた状態で環状補剛リブ３２を接合しても良い。   Furthermore, in the said 2nd Embodiment, although the cyclic | annular stiffening rib 32 was joined to the outer surface 12S of the steel pipe main-body part 12B by welding (continuous welding) etc., it is not restricted to this. For example, an annular stiffening rib 32 may be joined to the outer surface 12S of the steel pipe main body 12B by intermittent welding so that bending rigidity is not given to the side wall of the steel pipe main body 12B, or via a spacer such as a joint hardware. The annular stiffening rib 32 may be joined with a gap between the side wall of the steel pipe main body 12B.

また、上記第１，第２実施形態では、断熱材２４として、巻き付けタイプの断熱材を用いたがこれに限らない。断熱材としては、例えば、耐火性能を有する巻き付け系耐火被覆材、セラミックブランケット等を用いても良い。また、繊維混入けい酸カルシウム板、せっこうボード、強化せっこうボード、モルタルボード、ロックウールボード、セラミックファイバーボード、ＰＣ板、ＡＬＣパネル、押し出し成形セメント板等のボード系の材料を用いても良い。更に、鋼管本体部１２Ｂの周囲に仕上げ材２６を設置した後に、鋼管本体部１２Ｂと仕上げ材２６との間にモルタル等を充填して断熱層を形成しても良い。   Moreover, in the said 1st, 2nd embodiment, although the winding type heat insulating material was used as the heat insulating material 24, it is not restricted to this. As the heat insulating material, for example, a wrapping fireproof covering material having a fireproof performance, a ceramic blanket, or the like may be used. Further, board-based materials such as fiber-mixed calcium silicate board, gypsum board, reinforced gypsum board, mortar board, rock wool board, ceramic fiber board, PC board, ALC panel, and extruded cement board may be used. . Further, after the finishing material 26 is installed around the steel pipe main body 12B, a heat insulating layer may be formed by filling mortar or the like between the steel pipe main body 12B and the finishing material 26.

更に、上記第１，第２実施形態では、仕上げ材２６として薄鋼板を用いたがこれに限らない。仕上げ材としては、例えば、アルミニウム板やステンレス板を用いて意匠性を向上させても良いし、逆に、安価な金属板を用いてコスト削減を図っても良い。なお、安価な金属板を用いた場合は、表面を壁紙等で仕上げ、意匠性を向上させても良い。また、仕上げ材としては、例えば、厚紙系の壁紙やプラスチック合成繊維系の材料等で形成された仕上げ材、若しくは、せっこうボードや繊維混入けい酸カルシウム板等のボード材を用いても良い。   Furthermore, in the said 1st, 2nd embodiment, although the thin steel plate was used as the finishing material 26, it is not restricted to this. As the finishing material, for example, an aluminum plate or a stainless steel plate may be used to improve the design, and conversely, an inexpensive metal plate may be used to reduce costs. When an inexpensive metal plate is used, the surface may be finished with wallpaper or the like to improve the design. Further, as the finishing material, for example, a finishing material formed of a cardboard wallpaper or a plastic synthetic fiber material, or a board material such as a gypsum board or a fiber mixed calcium silicate board may be used.

更には、仕上げ材の基材に金属板を用いずに、せっこうボードや繊維混入けい酸カルシウム板等のボード材を直接仕上げ材として用いても良い。若しくは、例えば図１４（Ａ）及び図１４（Ｂ）に示すように帯状に加工した帯状薄鋼板２６Ｂを環状補剛リブ３２に溶接し、帯状薄鋼板２６Ｂにせっこうボード等の仕上げボード材２６Ｐをビス５０等で接合しても良い。   Furthermore, a board material such as a gypsum board or a fiber-mixed calcium silicate board may be directly used as a finishing material without using a metal plate as a base material of the finishing material. Alternatively, for example, as shown in FIGS. 14A and 14B, a belt-shaped thin steel plate 26B processed into a strip shape is welded to the annular stiffening rib 32, and the strip-shaped thin steel plate 26B is finished board material 26P such as a gypsum board. May be joined with screws 50 or the like.

なお、図１４（Ａ）及び図１４（Ｂ）では仕上げボード材２６Ｐを１枚張りとしたが、複数枚貼り付けても良い。更には、仕上げボード材２６Ｐに強化せっこうボード等の耐火性能に優れたボード材を用いることで耐火性能をさらに高めても良い。既存建物の無耐火被覆コンクリート充填鋼管柱（周囲に軽鉄スタッド１２４を立設し、これらの軽鉄スタッド１２４でせっこうボード等のボード材で周囲を仕上げている場合）の耐火補強として図１４（Ａ）及び図１４（Ｂ）に示す方法を用いた場合は、補強前に比べ耐火性能が向上するだけでなく、仕上げ材２６を含めた柱の水平断面積を小さくすることができる。また、図１４（Ａ）及び図１４（Ｂ）に示される変形例では、環状補剛リブ３２に帯状薄鋼板２６Ｂを接合したが、縦補剛リブ２２（図２（Ａ）参照）に帯状薄鋼板２６Ｂを接合しても良い。   In FIG. 14A and FIG. 14B, one finish board material 26P is stretched, but a plurality of finish board materials 26P may be attached. Furthermore, the fire resistance may be further increased by using a board material having excellent fire resistance such as a reinforced gypsum board as the finishing board 26P. FIG. 14 shows fireproof reinforcement of a fire-resistant coated concrete-filled steel pipe column of an existing building (when light iron studs 124 are erected around and the surroundings are finished with a board material such as a gypsum board with these light iron studs 124). When the methods shown in FIGS. 14A and 14B are used, not only the fire resistance is improved but also the horizontal cross-sectional area of the column including the finishing material 26 can be reduced as compared to before reinforcement. Further, in the modification shown in FIGS. 14A and 14B, the belt-like thin steel plate 26B is joined to the annular stiffening rib 32, but the belt-like stiffening rib 22 (see FIG. 2A) has a belt-like shape. The thin steel plate 26B may be joined.

また、上記第１，第２実施形態では、縦補剛リブ２２及び環状補剛リブ３２を断熱材２４と仕上げ材２６で被覆する、若しくは縦補剛リブ２２及び環状補剛リブ３２を断熱材２４で被覆することで、縦補剛リブ２２及び環状補剛リブの温度上昇を抑制する形態としてきたが、断熱材２４と仕上げ材２６を省略し、縦補剛リブ２２若しくは環状補剛リブ３２のみとしても良い。例えば、設計条件があまり厳しくない場合、具体的には、火災継続時間が短い場合、柱頭部に接合する梁の熱膨張による伸張長さがあまり大きくない場合、柱の負担する軸力が小さい場合などは、縦補剛リブ２２若しくは環状補剛リブ３２のみによる補強でも局部座屈Ｋの発生を抑制することが可能である。   In the first and second embodiments, the longitudinal stiffening rib 22 and the annular stiffening rib 32 are covered with the heat insulating material 24 and the finishing material 26, or the vertical stiffening rib 22 and the annular stiffening rib 32 are insulated. However, the heat insulating material 24 and the finishing material 26 are omitted, and the vertical stiffening rib 22 or the annular stiffening rib 32 is provided. Just as good. For example, when the design conditions are not so strict, specifically, when the fire duration is short, when the extension length due to thermal expansion of the beam joined to the column head is not very large, or when the axial force borne by the column is small The occurrence of local buckling K can be suppressed even by reinforcement using only the longitudinal stiffening rib 22 or the annular stiffening rib 32.

また、上記第１，第２実施形態では、内ダイアフラム１８を用いた内ダイアフラム形式のコンクリート充填鋼管柱１０を例に説明したが、上記実施形態は、通しダイアフラム形式や外ダイアフラム形式のコンクリート充填鋼管柱にも適用可能である。   Moreover, in the said 1st, 2nd embodiment, although the concrete filling steel pipe pillar 10 of the inner diaphragm type using the inner diaphragm 18 was demonstrated to the example, the said embodiment is a concrete filling steel pipe of a through diaphragm type or an outer diaphragm type. It can also be applied to pillars.

更に、鋼管柱１２は、断面略正方形の角形鋼管に限らず、断面長方形の角形鋼管や丸形鋼管を用いても良い。なお、断面長方形の角形鋼管では、短辺の長さが鋼管本体部の幅Ｄに相当し、丸形鋼管では、その直径が鋼管本体部の幅Ｄに相当する。また、鋼管柱の周方向（柱周方向）とは、角形鋼管のように複数の外側面１２Ｓを備える鋼管柱１２の場合は、鋼管柱１２の各外側面１２Ｓの幅方向に沿った方向（矢印Ｘ方向又は矢印Ｙ方向）を意味し、丸形鋼管のように断面円形の外側面を備える鋼管柱の場合は、円周に沿った方向（円周方向）を意味する。   Furthermore, the steel pipe column 12 is not limited to a square steel pipe having a substantially square cross section, and may be a square steel pipe or a round steel pipe having a rectangular cross section. In addition, in the rectangular steel pipe having a rectangular cross section, the length of the short side corresponds to the width D of the steel pipe main body, and in the case of a round steel pipe, the diameter corresponds to the width D of the steel pipe main body. Moreover, the circumferential direction (column circumferential direction) of a steel pipe column is the direction along the width direction of each outer side surface 12S of the steel pipe column 12 in the case of the steel pipe column 12 provided with several outer surface 12S like a square steel pipe ( In the case of a steel pipe column having an outer surface with a circular cross section like a round steel pipe, it means a direction along the circumference (circumferential direction).

また、鋼管柱１２には、耐火被覆を施しても良い。更に、上記第１，第２実施形態では、水平部材として鉄骨梁１６を例に説明したが、鉄骨梁１６に替えてスラブ（例えば、ＲＣ床スラブやフラットスラブ）等でも良い。   The steel pipe column 12 may be provided with a fireproof coating. Further, in the first and second embodiments, the steel beam 16 is described as an example of the horizontal member, but a slab (for example, an RC floor slab or a flat slab) may be used instead of the steel beam 16.

以上、本発明の第１，第２実施形態について説明したが、本発明はこうした実施形態に限定されるものでなく、第１，第２実施形態、及び各種の変形例を適宜組み合わせて用いても良いし、本発明の要旨を逸脱しない範囲において、種々なる態様で実施し得ることは勿論である。   The first and second embodiments of the present invention have been described above. However, the present invention is not limited to such embodiments, and the first and second embodiments and various modifications may be used in appropriate combination. Of course, various embodiments can be implemented without departing from the scope of the present invention.

１２ 鋼管柱
１２Ｓ 外側面
１４ 充填コンクリート
２０ コンクリート充填鋼管柱の耐火補強構造
２２ 縦補剛リブ（補剛リブ）
２４ 断熱材
２６ 仕上げ材
３０ コンクリート充填鋼管柱の耐火補強構造
３２ 環状補剛リブ（補剛リブ）
４４ 断熱材 12 Steel pipe column 12S Outer side surface 14 Filled concrete 20 Fireproof reinforcement structure of concrete filled steel tube column 22 Vertical stiffening rib (stiffening rib)
24 Heat Insulating Material 26 Finishing Material 30 Fireproof Reinforcement Structure of Concrete Filled Steel Pipe Column 32 Annular Stiffening Rib
44 Thermal insulation

Claims (4)

鋼管柱と、
前記鋼管柱内に充填された充填コンクリートと、
前記鋼管柱の外側面に設けられた補剛リブと、
前記補剛リブに隣接して配置され、前記鋼管柱の外側面を被覆する断熱材と、
前記断熱材を間に置いて前記鋼管柱の前記外側面と対向すると共に、前記補剛リブに支持された仕上げ材と、
を備えるコンクリート充填鋼管柱の耐火補強構造。 Steel pipe columns,
Filled concrete filled in the steel pipe column;
A stiffening rib provided on the outer surface of the steel pipe column;
A heat insulating material disposed adjacent to the stiffening rib and covering an outer surface of the steel pipe column;
A facing material that is opposed to the outer surface of the steel pipe column with the heat insulating material in between, and supported by the stiffening ribs;
A fireproof reinforcement structure for concrete filled steel pipe columns. 前記断熱材が、前記補剛リブの側面を被覆する請求項１に記載のコンクリート充填鋼管柱の耐火補強構造。   The fireproof reinforcing structure for a concrete-filled steel pipe column according to claim 1, wherein the heat insulating material covers a side surface of the stiffening rib. 前記仕上げ材が、前記補剛リブ及び前記断熱材に支持される請求項１又は請求項２に記載のコンクリート充填鋼管柱の耐火補強構造。 The fireproof reinforcing structure for a concrete-filled steel pipe column according to claim 1 or 2, wherein the finishing material is supported by the stiffening rib and the heat insulating material . 前記補剛リブが、前記鋼管柱の周方向に沿って配置されると共に該鋼管柱の軸方向に間隔を空けて複数設けられ、
前記断熱材が、前記鋼管柱の軸方向に隣接する前記補剛リブの間に設けられている請求項１〜請求項３の何れか１項に記載のコンクリート充填鋼管柱の耐火補強構造。 A plurality of the stiffening ribs are provided along the circumferential direction of the steel pipe column and provided with a plurality of intervals in the axial direction of the steel pipe column,
The fireproof reinforcing structure for a concrete-filled steel pipe column according to any one of claims 1 to 3, wherein the heat insulating material is provided between the stiffening ribs adjacent in the axial direction of the steel pipe column.
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