JP2012140824A - Concrete filled steel pipe column - Google Patents

Concrete filled steel pipe column Download PDF

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JP2012140824A
JP2012140824A JP2011000702A JP2011000702A JP2012140824A JP 2012140824 A JP2012140824 A JP 2012140824A JP 2011000702 A JP2011000702 A JP 2011000702A JP 2011000702 A JP2011000702 A JP 2011000702A JP 2012140824 A JP2012140824 A JP 2012140824A
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steel pipe
side wall
concrete
filled
reinforcing rib
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JP5839800B2 (en
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Toshihiko Nishimura
俊彦 西村
Tsutomu Nagaoka
勉 長岡
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Takenaka Komuten Co Ltd
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Takenaka Komuten Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a concrete filled steel pipe column having improved workability while inhibiting the local buckling of the side wall of a steel pipe.SOLUTION: Each side wall 12A of a steel pipe 12 is reinforced by a vertical reinforcing rib 20 disposed inside the steel pipe 12. The vertical reinforcing rib 20 is formed of a plate-like steel sheet, and disposed inside the steel pipe 12 with its longitudinal direction as the axial direction of the steel pipe 12. The vertical reinforcing rib 20 is disposed projecting from the side wall 12A of the steel pipe 12, with (the end face of) one end 20A in the cross direction abutting approximately perpendicular on the center in the cross direction of (the inner face of) the side wall 12A of the steel pipe 12 and the other end 20B in the cross direction directed inside the steel pipe 12. One end 20A (joint end) of the vertical reinforcing rib 20 is continuously welded to the side wall 12A of the steel pipe 12 in the longitudinal direction of the vertical reinforcing rib 20. Thus, out-of-plane rigidity is imparted to the side wall 12A of the steel pipe 12.

Description

本発明は、コンクリート充填鋼管柱に関する。   The present invention relates to a concrete-filled steel pipe column.

鋼管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（例えば、特許文献１）。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（負担軸力）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。   A concrete filled steel tube (CFT (Concrete Filled Steel Tube)) column in which concrete is filled in a steel pipe is known (for example, Patent Document 1). In general, the CFT column has a large axial force (burden axial force) that can be borne compared to a hollow steel tube column, and since the heat capacity increases as the concrete is filled, the CFT column is excellent in fire resistance. 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.

ここで、特許文献１に開示された技術では、鋼管の内周面に、当該鋼管の軸方向へ延びるリブ（フラットバー）が点溶接で取り付けられている。そして、火災時に、鋼管とコンクリートとの熱膨張差によってコンクリートに発生する軸方向の引張り力にリブが抵抗することにより、コンクリートに発生する水平方向のひび割れを抑制し、ＣＦＴ柱の座屈を防止している。   Here, in the technique disclosed in Patent Document 1, a rib (flat bar) extending in the axial direction of the steel pipe is attached to the inner peripheral surface of the steel pipe by spot welding. And in the event of a fire, the ribs resist the axial tensile force generated in the concrete due to the difference in thermal expansion between the steel pipe and the concrete, thereby suppressing the horizontal cracks generated in the concrete and preventing the CFT pillars from buckling. is doing.

しかしながら、特許文献１に開示された技術のように鋼管の内周面にリブを点溶接する構成では、火災時におけるコンクリートのひび割れが抑制されるものの、加熱されて耐力、剛性が低下した鋼管の変形を十分に規制することができず、当該内壁に局部座屈が発生する可能性がある。   However, in the configuration in which the ribs are spot-welded to the inner peripheral surface of the steel pipe as in the technique disclosed in Patent Document 1, cracks in the concrete during a fire are suppressed, but the steel pipe whose yield strength and rigidity are reduced by heating is reduced. Deformation cannot be sufficiently controlled, and local buckling may occur on the inner wall.

一方、断面十字形に組み合わされた２枚の鉄板を鋼管の内部に配置し、溶接で固定したコンクリート充填鋼管柱が知られている（例えば、特許文献２）。特許文献２に開示された技術では、２枚の鉄板によって鋼管の内部が４つの区画に仕切られる。従って、各区画にコンクリートを充填しなければならず、コンクリートの充填作業が煩雑化すると共に、各区画へのコンクリートの充填効率が低下する。   On the other hand, there is known a concrete-filled steel pipe column in which two steel plates combined in a cross-shaped cross section are arranged inside a steel pipe and fixed by welding (for example, Patent Document 2). In the technique disclosed in Patent Document 2, the inside of a steel pipe is partitioned into four sections by two iron plates. Therefore, it is necessary to fill each compartment with concrete, and the concrete filling operation becomes complicated, and the concrete filling efficiency into each compartment decreases.

特開平１０−２０４９９３号公報JP-A-10-204993 特開平９−８８２３８号公報Japanese Patent Laid-Open No. 9-88238

本発明は、上記の事実を考慮し、鋼管の側壁の局部座屈を抑制しつつ、施工性が向上されたコンクリート充填鋼管柱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 concrete-filled steel pipe column with improved workability while suppressing local buckling of the side wall of the steel pipe.

請求項１に記載のコンクリート充填鋼管柱は、鋼管と、前記鋼管の内部に、長手方向を前記鋼管の軸方向又は周方向にして配置されると共に、長手方向に沿って該鋼管の側壁に接合され、該側壁から突出する補強部材と、前記鋼管に充填される充填コンクリートと、を備えている。   The concrete-filled steel pipe column according to claim 1 is disposed inside the steel pipe and the steel pipe with the longitudinal direction being the axial direction or the circumferential direction of the steel pipe, and joined to the side wall of the steel pipe along the longitudinal direction. And a reinforcing member protruding from the side wall, and filled concrete filled in the steel pipe.

請求項１に記載のコンクリート充填鋼管柱によれば、鋼管の内部に配置された補強部材を、その長手方向に沿って鋼管の側壁に接合したことにより、従来技術（例えば、特許文献１）のように、鋼管の側壁にリブを点溶接する構成と比較して、鋼管の側壁の面外剛性が大きくなる。従って、鋼管の側壁の局部座屈が抑制されるため、コンクリート充填鋼管柱の耐火性能が向上する。   According to the concrete-filled steel pipe column of claim 1, the reinforcing member arranged inside the steel pipe is joined to the side wall of the steel pipe along the longitudinal direction thereof, so that the conventional technology (for example, Patent Document 1) is used. Thus, the out-of-plane rigidity of the side wall of the steel pipe is increased as compared with the configuration in which the rib is spot-welded to the side wall of the steel pipe. Therefore, since local buckling of the side wall of the steel pipe is suppressed, the fire resistance performance of the concrete-filled steel pipe column is improved.

また、本発明では、鋼管の側壁から補強部材が突出する構成であり、従来技術（例えば、特許文献２）のように、鋼管の内部を鉄板で仕切る構成ではない。従って、鋼管への充填コンクリートの充填作業の手間が低減されると共に、コンクリートの充填効率が向上する。従って、鋼管に対するコンクリート充填鋼管柱の施工性が向上する。   Moreover, in this invention, it is the structure which a reinforcement member protrudes from the side wall of a steel pipe, and is not the structure which partitions off the inside of a steel pipe with an iron plate like a prior art (for example, patent document 2). Therefore, the labor for filling the steel pipe with the filled concrete is reduced, and the concrete filling efficiency is improved. Therefore, the workability of the concrete-filled steel pipe column with respect to the steel pipe is improved.

請求項２に記載のコンクリート充填鋼管柱は、請求項１に記載のコンクリート充填鋼管柱において、前記補強部材が、板状の補強リブであり、前記補強リブの先端部にフランジ部が設けられている。   The concrete-filled steel pipe column according to claim 2 is the concrete-filled steel pipe column according to claim 1, wherein the reinforcing member is a plate-like reinforcing rib, and a flange portion is provided at a tip portion of the reinforcing rib. Yes.

請求項２に記載のコンクリート充填鋼管柱によれば、補強リブの先端部にフランジ部を設けたことにより、フランジ部を有しない補強リブと比較して、鋼管の側壁の面外剛性が飛躍的に増加する。従って、鋼管の側壁の局部座屈が抑制されるため、コンクリート充填鋼管柱の耐火性能が向上する。   According to the concrete-filled steel pipe column of claim 2, the flange portion is provided at the tip of the reinforcing rib, so that the out-of-plane rigidity of the side wall of the steel pipe is dramatically higher than that of the reinforcing rib having no flange portion. To increase. Therefore, since local buckling of the side wall of the steel pipe is suppressed, the fire resistance performance of the concrete-filled steel pipe column is improved.

請求項３に記載のコンクリート充填鋼管柱は、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において、前記補強部材が、前記鋼管の側壁に連続溶接又は断続溶接で接合されている。   The concrete-filled steel pipe column according to claim 3 is the concrete-filled steel pipe column according to claim 1 or 2, wherein the reinforcing member is joined to the side wall of the steel pipe by continuous welding or intermittent welding.

請求項３に記載のコンクリート充填鋼管柱によれば、鋼管の側壁に補強部材を連続溶接又は断続溶接で接合したことにより、従来技術（例えば、特許文献１）のように、鋼管の側壁にリブを点溶接する構成と比較して、鋼管の側壁の面外剛性が大きくなる。従って、鋼管の側壁の局部座屈が抑制されるため、コンクリート充填鋼管柱の耐火性能が向上する。   According to the concrete-filled steel pipe column according to claim 3, the reinforcing member is joined to the side wall of the steel pipe by continuous welding or intermittent welding, so that the ribs are formed on the side wall of the steel pipe as in the prior art (for example, Patent Document 1). Compared with the configuration of spot welding, the out-of-plane rigidity of the side wall of the steel pipe is increased. Therefore, since local buckling of the side wall of the steel pipe is suppressed, the fire resistance performance of the concrete-filled steel pipe column is improved.

本発明は、上記の構成としたので、鋼管の側壁の局部座屈を抑制しつつ、施工性も向上することができる。   Since this invention set it as said structure, workability can also be improved, suppressing the local buckling of the side wall of a steel pipe.

本発明の一実施形態に係るコンクリート充填鋼管柱を示す斜視図である。It is a perspective view which shows the concrete filling steel pipe column which concerns on one Embodiment of this invention. 本発明の一実施形態に係るコンクリート充填鋼管柱を示す図１の平断面図である。It is the plane sectional view of Drawing 1 showing the concrete filling steel pipe pillar concerning one embodiment of the present invention. 本発明の一実施形態に係るコンクリート充填鋼管柱を示す図１の縦断面図である。It is a longitudinal cross-sectional view of FIG. 1 which shows the concrete filling steel pipe column which concerns on one Embodiment of this invention. （Ａ）及び（Ｂ）は、本発明の一実施形態における補強部材の変形例を示す図２に相当する平断面図である。(A) And (B) is a plane sectional view equivalent to Drawing 2 showing the modification of the reinforcing member in one embodiment of the present invention. （Ａ）及び（Ｂ）は、本発明の一実施形態における補強部材の変形例を示す図２に相当する平断面図である。(A) And (B) is a plane sectional view equivalent to Drawing 2 showing the modification of the reinforcing member in one embodiment of the present invention. （Ａ）は、本発明の一実施形態における補強部材の変形例を示す図２に相当する平断面図であり、（Ｂ）は、本発明の一実施形態における補強部材の変形例を示す斜視図である。(A) is a plane sectional view equivalent to Drawing 2 showing a modification of a reinforcement member in one embodiment of the present invention, and (B) is a perspective view showing a modification of a reinforcement member in one embodiment of the present invention. FIG. （Ａ）は、本発明の一実施形態における補強部材の変形例を示す図７（Ｂ）の７−７線断面図であり、（Ｂ）は、本発明の一実施形態における補強部材の変形例を示す図３に相当する平断面図である。(A) is a 7-7 line sectional view of Drawing 7 (B) showing a modification of a reinforcing member in one embodiment of the present invention, and (B) is a modification of a reinforcing member in one embodiment of the present invention. It is a plane sectional view equivalent to Drawing 3 showing an example. 本発明の一実施形態における鋼管の変形例を示す図２に相当する平断面図である。It is a plane sectional view equivalent to Drawing 2 showing the modification of the steel pipe in one embodiment of the present invention. 耐火試験の試験結果であり、加熱時間と鋼管の軸方向の変形量との関係を示すグラフである。It is a test result of a fire resistance test, and is a graph showing the relationship between the heating time and the deformation amount in the axial direction of the steel pipe.

以下、図面を参照しながら、本発明の一実施形態に係るコンクリート充填鋼管柱について説明する。なお、各図において適宜図示される矢印Ｚは鋼管の軸方向を示している。   Hereinafter, a concrete-filled steel pipe column according to an embodiment of the present invention will be described with reference to the drawings. In each figure, an arrow Z shown as appropriate indicates the axial direction of the steel pipe.

図１及び図２には、一実施形態に係るコンクリート充填鋼管柱１０の一部が示されている。コンクリート充填鋼管柱１０は、例えば、高層建物や超高層建物等の高い強度（例えば、設計基準強度で６０Ｎ／ｍｍ２以上、軸力比（軸力／（柱の水平断面積×充填コンクリートの設計基準強度）で０．３以上の高い軸力）が求められる柱として好適に用いられるものである。 1 and 2 show a part of a concrete-filled steel pipe column 10 according to an embodiment. The concrete-filled steel pipe column 10 has, for example, a high strength such as a high-rise building or a super-high-rise building (for example, a design standard strength of 60 N / mm 2 or more, an axial force ratio (axial force / (horizontal cross-sectional area of a column × filled concrete design It is preferably used as a column for which a high axial force) of 0.3 or more is required as a reference strength.

コンクリート充填鋼管柱１０は、鋼管１２と、補強部材（補強リブ）としての縦補強リブ２０と、鋼管１２の内部に充填される充填コンクリート１４を備えている。鋼管１２は角形鋼管からなり、軸方向（矢印Ｚ方向）を上下方向として、図示しない基礎等の上に立てられている。なお、鋼管１２の外周部には耐火被覆が施されておらず、コンクリート充填鋼管柱１０は、無耐火被覆のコンクリート充填鋼管柱（無耐火被覆ＣＦＴ柱）とされている。   The concrete-filled steel pipe column 10 includes a steel pipe 12, vertical reinforcing ribs 20 as reinforcing members (reinforcing ribs), and filled concrete 14 filled in the steel pipe 12. The steel pipe 12 is formed of a square steel pipe, and is erected on a foundation or the like (not shown) with the axial direction (arrow Z direction) as the vertical direction. In addition, the fireproof coating is not given to the outer peripheral part of the steel pipe 12, and the concrete filling steel pipe pillar 10 is made into the concrete filling steel pipe pillar (fireproof covering CFT pillar) of a fireproof coating.

鋼管１２の各側壁１２Ａは、鋼管１２の内部に配置された縦補強リブ２０によって補強されている。縦補強リブ２０は板状の鋼板で構成され、長手方向を鋼管１２の軸方向にして鋼管１２の内部に配置され、鋼管１２の下端部から上端部に渡って設けられている。縦補強リブ２０は、図２に示されるように、その幅方向の一端部２０Ａ（の端面）を鋼管１２の側壁１２Ａ（の内面）の幅方向の中央部に略垂直に突き当てると共に、その幅方向の他端部２０Ｂを鋼管１２の内側へ向け、鋼管１２の側壁１２Ａから突出した状態で配置されている。縦補強リブ２０の一端部２０Ａ（接合端部）は、当該縦補強リブ２０の長手方向に沿って鋼管１２の側壁１２Ａに連続溶接されている。この連続溶接は、縦補強リブ２０の長手方向の全長に渡っている。この縦補強リブ２０によって、鋼管１２の側壁１２Ａに面外剛性が付与されている。   Each side wall 12 </ b> A of the steel pipe 12 is reinforced by vertical reinforcing ribs 20 arranged inside the steel pipe 12. The longitudinal reinforcing rib 20 is composed of a plate-shaped steel plate, and is disposed inside the steel pipe 12 with the longitudinal direction being the axial direction of the steel pipe 12, and is provided from the lower end portion to the upper end portion of the steel pipe 12. As shown in FIG. 2, the longitudinal reinforcing rib 20 abuts the one end portion 20 </ b> A (the end surface thereof) in the width direction substantially perpendicularly to the center portion in the width direction of the side wall 12 </ b> A (the inner surface thereof) of the steel pipe 12. It arrange | positions in the state which protruded from the side wall 12A of the steel pipe 12 toward the inner side of the steel pipe 12, and the other end part 20B of the width direction. One end 20 </ b> A (joint end) of the longitudinal reinforcing rib 20 is continuously welded to the side wall 12 </ b> A of the steel pipe 12 along the longitudinal direction of the longitudinal reinforcing rib 20. This continuous welding extends over the entire length of the longitudinal reinforcing rib 20 in the longitudinal direction. The longitudinal reinforcing rib 20 provides out-of-plane rigidity to the side wall 12 </ b> A of the steel pipe 12.

なお、縦補強リブ２０は、対向する鋼管１２の側壁１２Ａ間にまたがっておらず、対向する一方の側壁１２Ａに接合された状態で、対向する他の側壁１２Ａとの間に間隔が空けられている。つまり、縦補強リブ２０の他端部２０Ｂと対向する他の側壁１２Ａとは接触していない。   The longitudinal reinforcing ribs 20 do not span between the side walls 12A of the opposing steel pipes 12, but are spaced from the other side walls 12A facing each other while being joined to the opposite side wall 12A. Yes. That is, the other side wall 12A facing the other end portion 20B of the vertical reinforcing rib 20 is not in contact.

充填コンクリート１４は、鋼管１２の内部に充填されたコンクリートが硬化したものであり、当該充填コンクリート１４の外周部に縦補強リブ２０が埋設されている。   The filled concrete 14 is obtained by curing concrete filled in the steel pipe 12, and vertical reinforcing ribs 20 are embedded in the outer peripheral portion of the filled concrete 14.

次に、本実施形態に係るコンクリート充填鋼管柱の作用について説明する。   Next, the operation of the concrete-filled steel pipe column according to this embodiment will be described.

例えば、図３に示されるように、火災によってコンクリート充填鋼管柱１０が矢印Ａ方向から加熱されると、先ず、温度上昇に伴って鋼管１２が熱膨張し、鋼管１２が軸方向（矢印Ｚ方向）へ伸張すると共に、徐々に軟化して剛性が低下する。また、鋼管１２の側壁１２Ａを介して、当該側壁１２Ａを内部から支持する充填コンクリート１４の外周部に熱が伝達され、当該外周部の温度が上昇する。そして、充填コンクリート１４の外周部の温度が所定温度（熱劣化温度）以上になると、充填コンクリート１４の外周部が熱劣化する。これにより、充填コンクリート１４の外周部が脆く、脆性的に破壊され易くなり、鋼管１２の側壁１２Ａの支持強度が低下する。この結果、図中の二点鎖線で示されるように、温度上昇により剛性が低下した鋼管１２の側壁１２Ａが面外方向へ凸状に湾曲し、局部座屈する。そして、鋼管１２の側壁１２Ａが局部座屈すると、矢印Ｑで示されるように、内側へ凸状に湾曲した鋼管１２の側壁１２Ａによって充填コンクリート１４の外周部が押圧され、当該外周部が圧壊する。また、鋼管１２の側壁１２Ａに局部座屈が発生すると、鋼管１２が軸方向（矢印Ｚ方向）に縮むため、鋼管１２が負担していた軸力Ｆの一部が充填コンクリート１４に導入され、充填コンクリート１４の負担軸力が増加する。これにより、充填コンクリート１４の外周部の圧壊が促進され、コンクリート充填鋼管柱１０の耐力（軸耐力）が急激に低下し、最終的に破壊に至る。   For example, as shown in FIG. 3, when the concrete-filled steel pipe column 10 is heated from the direction of arrow A due to a fire, first, the steel pipe 12 is thermally expanded as the temperature rises, and the steel pipe 12 is axially (arrow Z direction). ) And gradually softens to lower the rigidity. Moreover, heat is transmitted to the outer peripheral part of the filling concrete 14 which supports the said side wall 12A from the inside via the side wall 12A of the steel pipe 12, and the temperature of the said outer peripheral part rises. And when the temperature of the outer peripheral part of the filling concrete 14 becomes more than predetermined temperature (thermal deterioration temperature), the outer peripheral part of the filling concrete 14 will be thermally deteriorated. Thereby, the outer peripheral part of the filling concrete 14 becomes brittle, and it becomes easy to break brittlely, and the support strength of the side wall 12A of the steel pipe 12 is lowered. As a result, as indicated by a two-dot chain line in the figure, the side wall 12A of the steel pipe 12 whose rigidity has decreased due to temperature rise is curved in a convex shape in the out-of-plane direction, and is locally buckled. When the side wall 12A of the steel pipe 12 is locally buckled, as indicated by an arrow Q, the outer peripheral portion of the filled concrete 14 is pressed by the side wall 12A of the steel pipe 12 that is curved inwardly, and the outer peripheral portion is crushed. . Further, when local buckling occurs on the side wall 12A of the steel pipe 12, the steel pipe 12 contracts in the axial direction (arrow Z direction), so a part of the axial force F that the steel pipe 12 bears is introduced into the filled concrete 14, The burden axial force of the filling concrete 14 increases. Thereby, the crushing of the outer peripheral part of the filling concrete 14 is accelerated | stimulated, and the yield strength (axial strength) of the concrete filling steel pipe column 10 falls rapidly, and finally leads to destruction.

このように鋼管１２の側壁１２Ａに局部座屈が発生すると、充填コンクリート１４が所定の耐力（火災時耐力）を発揮する前に、コンクリート充填鋼管柱１０は、脆性的に崩壊してしまう。   When local buckling occurs in the side wall 12A of the steel pipe 12 in this way, the concrete-filled steel pipe column 10 collapses brittlely before the filled concrete 14 exhibits a predetermined strength (fire-proof strength).

そこで、本実施形態では、鋼管１２の各側壁１２Ａの幅方向の中央部に、鋼管１２の軸方向へ延びる縦補強リブ２０を接合し、当該側壁１２Ａを補強している。これにより、鋼管１２の側壁１２Ａの面外剛性が増加するため、当該側壁１２Ａの局部座屈が抑制される。また、鋼管１２の側壁１２Ａの局部座屈を抑制することで、充填コンクリート１４の外周部の圧壊も抑制される。   Therefore, in the present embodiment, the longitudinal reinforcing rib 20 extending in the axial direction of the steel pipe 12 is joined to the central portion in the width direction of each side wall 12A of the steel pipe 12 to reinforce the side wall 12A. Thereby, since the out-of-plane rigidity of the side wall 12A of the steel pipe 12 increases, local buckling of the side wall 12A is suppressed. Moreover, the collapse of the outer peripheral part of the filling concrete 14 is also suppressed by suppressing the local buckling of the side wall 12 </ b> A of the steel pipe 12.

このように本実施形態では、鋼管１２の各側壁１２Ａを縦補強リブ２０で補強することにより、火災時における鋼管１２の側壁１２Ａの局部座屈が抑制される。従って、コンクリート充填鋼管柱１０が所定の耐力（軸耐力）を発揮可能になるため、コンクリート充填鋼管柱１０の耐火性能が向上する。   Thus, in this embodiment, local buckling of side wall 12A of steel pipe 12 at the time of a fire is suppressed by reinforcing each side wall 12A of steel pipe 12 with longitudinal reinforcement rib 20. Therefore, since the concrete-filled steel pipe column 10 can exhibit a predetermined proof stress (axial proof stress), the fire resistance performance of the concrete-filled steel pipe column 10 is improved.

また、本実施形態では、縦補強リブ２０の幅方向の一端部２０Ａが、当該縦補強リブ２０の長手方向に沿って鋼管１２の側壁１２Ａに連続溶接で接合されている。従って、従来技術（例えば、特許文献１）のように、鋼管の側壁にリブを点溶接する構成と比較して、鋼管１２の側壁１２Ａと縦補強リブ２０との一体性が向上するため、鋼管１２の側壁１２Ａの面外剛性が大きくなる。従って、鋼管１２の側壁１２Ａの局部座屈に対する抑制効果が向上する。   In the present embodiment, one end portion 20 </ b> A in the width direction of the longitudinal reinforcing rib 20 is joined to the side wall 12 </ b> A of the steel pipe 12 by continuous welding along the longitudinal direction of the longitudinal reinforcing rib 20. Therefore, since the integrity of the side wall 12A of the steel pipe 12 and the longitudinal reinforcing rib 20 is improved as compared with the configuration in which the rib is spot-welded to the side wall of the steel pipe as in the prior art (for example, Patent Document 1), the steel pipe is improved. The out-of-plane rigidity of the 12 side walls 12A is increased. Accordingly, the effect of suppressing the local buckling of the side wall 12A of the steel pipe 12 is improved.

更に、本実施形態は、鋼管１２の側壁１２Ａから縦補強リブ２０を突出させる構成であり、従来技術（例えば、特許文献２）のように、鋼管の内部を鉄板で仕切る構成ではない。従って、鋼管１２への充填コンクリート１４の充填作業の手間が低減されると共に、鋼管１２に対する充填コンクリート１４の充填効率が向上する。また、従来技術（例えば、特許文献２）のように、平面視にて十字形に組み合わされた２枚の鉄板を鋼管の内部に配置し、当該鋼管の内部を２枚の鉄板で仕切る構成では、鋼管の側壁に２枚の鉄板を溶接するための作業スペースが狭くなり、溶接作業に手間がかかる。これに対して本実施形態では、鋼管１２の側壁１２Ａから縦補強リブ２０が突出する構成であるため、溶接のための作用スペースを広く確保することができる。従って、コンクリート充填鋼管柱１０の施工性が向上する。   Furthermore, this embodiment is the structure which makes the vertical reinforcement rib 20 protrude from the side wall 12A of the steel pipe 12, and is not the structure which partitions off the inside of a steel pipe with an iron plate like a prior art (for example, patent document 2). Therefore, the labor for filling the steel pipe 12 with the filled concrete 14 is reduced, and the filling efficiency of the filled concrete 14 into the steel pipe 12 is improved. Further, as in the prior art (for example, Patent Document 2), in a configuration in which two steel plates combined in a cross shape in a plan view are arranged inside a steel pipe and the inside of the steel pipe is partitioned by two iron plates. The working space for welding the two steel plates to the side wall of the steel pipe is narrowed, and the welding work is troublesome. On the other hand, in this embodiment, since the vertical reinforcing rib 20 protrudes from the side wall 12A of the steel pipe 12, a wide working space for welding can be secured. Therefore, the workability of the concrete-filled steel pipe column 10 is improved.

また、縦補強リブ２０は、面外剛性が最も低い鋼管１２の側壁１２Ａの中央部に設けられている。従って、鋼管１２の側壁１２Ａの局部座屈を効率的に抑制することができる。更に、縦補強リブ２０は、鋼管１２の下端部から上端部に渡って設けられている。従って、鋼管１２の軸方向の全域に渡って、鋼管１２の側壁１２Ａの局部座屈を抑制することができる。   Further, the vertical reinforcing rib 20 is provided at the center of the side wall 12A of the steel pipe 12 having the lowest out-of-plane rigidity. Therefore, local buckling of the side wall 12A of the steel pipe 12 can be efficiently suppressed. Further, the longitudinal reinforcing rib 20 is provided from the lower end portion of the steel pipe 12 to the upper end portion. Therefore, the local buckling of the side wall 12A of the steel pipe 12 can be suppressed over the entire area of the steel pipe 12 in the axial direction.

次に、本実施系形態に係るコンクリート充填鋼管柱の変形例について説明する。   Next, a modification of the concrete-filled steel pipe column according to the present embodiment will be described.

上記実施形態では、補強部材として、板状の縦補強リブ２０を用いたがこれに限らない。補強部材としては、例えば、図４（Ａ）に示されるように、断面Ｔ字形状の縦補強部材２４を用いても良い。縦補強部材２４はＴ形鋼で構成され、補強リブとしてのウェブ部２４Ｗとフランジ部２４Ｆを備えている。ウェブ部２４Ｗの幅方向の一端部は、鋼管１２の側壁１２Ａの幅方向の中央部に略垂直に突き当てられ、当該縦補強部材２４の長手方向に沿って鋼管１２の側壁１２Ａに連続溶接で接合されている。また、鋼管１２の側壁１２Ａから突出するウェブ部２４Ｗの幅方向の他端部には、鋼管１２の側壁１２Ａと対向するフランジ部２４Ｆが設けられている。   In the above embodiment, the plate-like vertical reinforcing rib 20 is used as the reinforcing member, but the present invention is not limited to this. As the reinforcing member, for example, as shown in FIG. 4A, a vertical reinforcing member 24 having a T-shaped cross section may be used. The vertical reinforcing member 24 is made of T-shaped steel and includes a web portion 24W and a flange portion 24F as reinforcing ribs. One end portion in the width direction of the web portion 24W is abutted substantially perpendicularly to the center portion in the width direction of the side wall 12A of the steel pipe 12, and is continuously welded to the side wall 12A of the steel pipe 12 along the longitudinal direction of the longitudinal reinforcing member 24. It is joined. Further, a flange portion 24F facing the side wall 12A of the steel pipe 12 is provided at the other end portion in the width direction of the web portion 24W protruding from the side wall 12A of the steel pipe 12.

このように、縦補強部材２４のフランジ部２４Ｆを鋼管１２の側壁１２Ａに対向させることにより、側壁１２Ａ及びフランジ部２４Ｆの断面２次モーメントが、側壁１２Ａとフランジ部２４Ｆとの中心線間の距離Ｌ１の二乗に比例して増加する。この結果、鋼管１２の側壁１２Ａの面外剛性が飛躍的に増加する。従って、鋼管１２の側壁１２Ａの局部座屈に対する抑制効果が向上する。 Thus, by making the flange portion 24F of the longitudinal reinforcing member 24 face the side wall 12A of the steel pipe 12, the cross-sectional secondary moment of the side wall 12A and the flange portion 24F is the distance between the center lines of the side wall 12A and the flange portion 24F. It increases in proportion to the square of L 1. As a result, the out-of-plane rigidity of the side wall 12A of the steel pipe 12 increases dramatically. Accordingly, the effect of suppressing the local buckling of the side wall 12A of the steel pipe 12 is improved.

また、図４（Ｂ）に示されるように、補強部材として、断面Ｃ字形状の縦補強部材２６を用いても良い。縦補強部材２６はＣ形鋼で構成され、補強リブとしてのウェブ部２６Ｗと一対のフランジ部２６Ｆ１，２６Ｆ２を備えている。ウェブ部２６Ｗの幅方向の一端部に設けられたフランジ部２６Ｆ１は、鋼管１２の側壁１２Ａの幅方向の中央部に重ねられ、当該縦補強部材２６の長手方向に沿って鋼管１２の側壁１２Ａに連続溶接で接合されている。また、ウェブ部２６Ｗの幅方向の他端部（先端部）に設けられたフランジ部２６Ｆ２は、鋼管１２の側壁１２Ａと対向している。これにより、前述したように、側壁１２Ａ及びフランジ部２６Ｆ２の断面２次モーメントが、側壁１２Ａとフランジ部２６Ｆ２の中心線間の距離Ｌ２の二乗に比例して増加する。この結果、鋼管１２の側壁１２Ａの面外剛性が飛躍的に増加する。従って、鋼管１２の側壁１２Ａの局部座屈に対する抑制効果が向上する。
なお、図示を省略するが、フランジ部を備える補強部材として、Ｌ形鋼、Ｈ形鋼、Ｉ形鋼等を用いても良い。 Further, as shown in FIG. 4B, a longitudinal reinforcing member 26 having a C-shaped cross section may be used as the reinforcing member. The vertical reinforcing member 26 is made of C-shaped steel and includes a web portion 26W as a reinforcing rib and a pair of flange portions 26F1 and 26F2. The flange portion 26F1 provided at one end portion in the width direction of the web portion 26W is overlapped with the center portion in the width direction of the side wall 12A of the steel pipe 12, and is disposed on the side wall 12A of the steel pipe 12 along the longitudinal direction of the vertical reinforcing member 26. Joined by continuous welding. Further, the flange portion 26F2 provided at the other end portion (tip portion) in the width direction of the web portion 26W faces the side wall 12A of the steel pipe 12. Thus, as described above, the second moment of the side wall 12A and the flange portion 26F2 is increased in proportion to the square of the distance L 2 between the center line of the side wall 12A and the flange portion 26F2. As a result, the out-of-plane rigidity of the side wall 12A of the steel pipe 12 increases dramatically. Accordingly, the effect of suppressing the local buckling of the side wall 12A of the steel pipe 12 is improved.
In addition, although illustration is abbreviate | omitted, you may use L shape steel, H shape steel, I shape steel, etc. as a reinforcement member provided with a flange part.

また、上記実施形態では、鋼管１２の各側壁１２Ａの幅方向の中央部に縦補強リブ２０を設けたが、縦補強リブ２０を設ける位置は適宜変更可能である。また、上記実施形態では、鋼管１２の各側壁１２Ａに対し、１つの縦補強リブ２０を設けたが、鋼管１２の各側壁１２Ａに対し、複数の縦補強リブ２０を当該側壁１２Ａの幅方向に間隔を空けて設けても良い。更に、上記実施形態では、鋼管１２の下端部から上端部に渡って縦補強リブ２０を設けたが、長手方向の長さが短くされた複数の縦補強リブ２０を、鋼管１２の軸方向に間隔を空けて設けても良い。   Moreover, in the said embodiment, although the vertical reinforcement rib 20 was provided in the center part of the width direction of each side wall 12A of the steel pipe 12, the position which provides the vertical reinforcement rib 20 can be changed suitably. Moreover, in the said embodiment, although the one vertical reinforcement rib 20 was provided with respect to each side wall 12A of the steel pipe 12, several vertical reinforcement rib 20 is provided in the width direction of the said side wall 12A with respect to each side wall 12A of the steel pipe 12. An interval may be provided. Furthermore, in the said embodiment, although the vertical reinforcement rib 20 was provided ranging from the lower end part to the upper end part of the steel pipe 12, the some longitudinal reinforcement rib 20 by which the length of the longitudinal direction was shortened is made to the axial direction of the steel pipe 12. An interval may be provided.

また、図５（Ａ）に示されるように、縦補強リブ２０の幅方向の他端部２０Ｂ（先端部）に沿って鉄筋、ＰＣ鋼棒等の棒状部材２８を設け、補強効果を向上させても良いし、図５（Ｂ）に示されるように、補強部材として鉄筋、ＰＣ鋼棒等の棒状部材３０を用いても良い。また、図６（Ａ）及び図６（Ｂ）に示されるように、鋼管１２の各側壁１２Ａに対し、複数の棒状部材３０を側壁１２Ａの幅方向に間隔を空けて配置し、これらの棒状部材３０を連結部材３２で連結しても良い。連結部材３２は鉄筋、ＰＣ鋼棒等で構成され、棒状部材３０と交差する方向に延びると共に、鋼管１２の軸方向に間隔を空けて複数設けられている。これらの棒状部材３０と連結部材３２とは、各々の交差部において溶接等で接合されている。即ち、棒状部材３０と連結部材３２とは、格子状（網目状）に連結され、いわゆるメッシュ筋を構成している。   Further, as shown in FIG. 5A, a bar-shaped member 28 such as a reinforcing bar or a PC steel bar is provided along the other end 20B (tip) in the width direction of the longitudinal reinforcing rib 20 to improve the reinforcing effect. Alternatively, as shown in FIG. 5B, a bar-shaped member 30 such as a reinforcing bar or a PC steel bar may be used as the reinforcing member. Further, as shown in FIGS. 6A and 6B, a plurality of bar-shaped members 30 are arranged in the width direction of the side wall 12A with respect to each side wall 12A of the steel pipe 12, and these bar-shaped The member 30 may be connected by the connecting member 32. The connecting member 32 is composed of a reinforcing bar, a PC steel bar, or the like, and extends in a direction intersecting with the bar-shaped member 30 and is provided in a plurality with an interval in the axial direction of the steel pipe 12. The rod-shaped member 30 and the connecting member 32 are joined by welding or the like at each intersection. That is, the rod-shaped member 30 and the connecting member 32 are connected in a lattice shape (mesh shape) to form a so-called mesh streak.

このように、鋼管１２の各側壁１２Ａに対し、複数の棒状部材３０を接合すると共に、これらの棒状部材３０を連結部材３２で連結することにより、各側壁１２Ａに対する補強効果が向上する。従って、鋼管１２の側壁１２Ａの局部座屈に対する抑制効果が向上する。   As described above, by joining the plurality of bar-shaped members 30 to the respective side walls 12A of the steel pipe 12, and connecting these bar-shaped members 30 with the connecting members 32, the reinforcing effect on the respective side walls 12A is improved. Accordingly, the effect of suppressing the local buckling of the side wall 12A of the steel pipe 12 is improved.

更に、上記実施形態では、縦補強リブ２０を鋼管１２の軸方向に沿って配置したが、例えば、鋼管１２の軸方向に対して傾斜する方向に沿って縦補強リブ２０を配置しても良い。また、図７（Ａ）及び図７（Ｂ）に示されるように、鋼管１２の周方向に沿って、補強部材としての横補強リブ２２を配置しても良い。具体的には、横補強リブ２２は板状の鋼板で構成され、長手方向を鋼管１２の周方向（側壁１２Ａの幅方向）にして配置されている。また、横補強リブ２２は、鋼管１２の側壁１２Ａの幅方向の略全長に渡って設けられている。更に、横補強リブ２２は、図７（Ｂ）に示されるように、各側壁１２Ａに対し、鋼管１２の軸方向に間隔を空けて複数設けられている。この横補強リブ２２によって鋼管１２の側壁１２Ａに面外剛性を付与することにより、当該側壁１２Ａの局部座屈が抑制される。従って、上記と同様の効果を得ることができる。   Furthermore, in the said embodiment, although the vertical reinforcement rib 20 was arrange | positioned along the axial direction of the steel pipe 12, you may arrange | position the vertical reinforcement rib 20 along the direction which inclines with respect to the axial direction of the steel pipe 12, for example. . Further, as shown in FIGS. 7A and 7B, lateral reinforcing ribs 22 as reinforcing members may be arranged along the circumferential direction of the steel pipe 12. Specifically, the lateral reinforcing ribs 22 are made of plate-shaped steel plates, and are arranged with the longitudinal direction being the circumferential direction of the steel pipe 12 (the width direction of the side wall 12A). The lateral reinforcing rib 22 is provided over substantially the entire length in the width direction of the side wall 12A of the steel pipe 12. Further, as shown in FIG. 7B, a plurality of lateral reinforcing ribs 22 are provided at intervals in the axial direction of the steel pipe 12 with respect to each side wall 12A. By imparting out-of-plane rigidity to the side wall 12 </ b> A of the steel pipe 12 by the lateral reinforcing rib 22, local buckling of the side wall 12 </ b> A is suppressed. Therefore, the same effect as described above can be obtained.

なお、ここでいう鋼管の周方向とは、角形鋼管のように複数の側壁を備える鋼管の場合は、横補強リブ２２が接合される鋼管１２の側壁１２Ａの幅方向に沿った方向を意味し、後述する丸形鋼管４２（図８参照）のように断面円形形状の側壁を備える鋼管の場合は、側壁４２Ａに沿った円周方向を意味する。   In addition, the circumferential direction of a steel pipe here means the direction along the width direction of the side wall 12A of the steel pipe 12 to which the horizontal reinforcing rib 22 is joined in the case of a steel pipe having a plurality of side walls like a square steel pipe. In the case of a steel pipe having a side wall with a circular cross section like a round steel pipe 42 (see FIG. 8) to be described later, it means the circumferential direction along the side wall 42A.

また、本変形例では、横補強リブ２２を鋼管１２の側壁１２Ａの幅方向の略全長に渡って設けたが、長手方向の長さが短くされた複数の横補強リブ２２を、鋼管１２の側壁１２Ａの幅方向の中央部や他の部位に設けても良い。また、鋼管１２の各側壁１２Ａに接触される４枚の横補強リブ２２を枠状に連結しても良い。更に、前述した縦補強リブと同様に、フランジ部を備えるＴ形鋼、Ｃ形鋼等で横補強リブ２２を構成しても良い。   In the present modification, the lateral reinforcing ribs 22 are provided over substantially the entire length in the width direction of the side wall 12 </ b> A of the steel pipe 12, but a plurality of lateral reinforcing ribs 22 whose lengths in the longitudinal direction are shortened are provided on the steel pipe 12. You may provide in the center part of the width direction of 12 A of side walls, and another site | part. Moreover, you may connect the four horizontal reinforcement ribs 22 contacted to each side wall 12A of the steel pipe 12 in frame shape. Further, similarly to the longitudinal reinforcing ribs described above, the lateral reinforcing ribs 22 may be constituted by T-shaped steel, C-shaped steel or the like having a flange portion.

更にまた、横補強リブ２２は、鋼管１２の仕口部（鉄骨梁との接合部）にも設けることができる。ここで、鋼管１２の仕口部における側壁１２Ａには、内ダイアフラムが設けられることが多い。この内ダイアフラムは、鉄骨梁のフランジと連続するように設けられる。これに対して横補強リブ２２は、鉄骨梁のフランジと連続させても良いし、連続させなくても良い。なお、横補強リブ２２を鉄骨梁のフランジと連続させた場合は、横補強リブ２２が内ダイアフラムとしても機能する。一方、鋼管１２の仕口部は、前述した内ダイアフラム等によって一般に強固に補強されるため、他の部位と比較して側壁１２Ａが局部座屈し難い。従って、鋼管１２の仕口部に横補強リブ２２を設けずに、鋼管１２の上下の仕口部間にのみ横補強リブ２２を設けることで、コスト削減を図りつつ、鋼管１２の側壁１２Ａの局部座屈を効率的に抑制することができる。   Furthermore, the lateral reinforcing ribs 22 can be provided also at the joint portion (joint portion with the steel beam) of the steel pipe 12. Here, the inner diaphragm is often provided on the side wall 12 </ b> A of the joint portion of the steel pipe 12. The inner diaphragm is provided so as to be continuous with the flange of the steel beam. On the other hand, the lateral reinforcing ribs 22 may be continuous with the flange of the steel beam or may not be continuous. When the lateral reinforcing rib 22 is made continuous with the flange of the steel beam, the lateral reinforcing rib 22 also functions as an inner diaphragm. On the other hand, since the joint portion of the steel pipe 12 is generally strongly reinforced by the above-described inner diaphragm or the like, the side wall 12A is less likely to be locally buckled as compared with other portions. Accordingly, by providing the horizontal reinforcing ribs 22 only between the upper and lower joint portions of the steel pipe 12 without providing the horizontal reinforcing ribs 22 at the joint portion of the steel pipe 12, the cost of the side wall 12A of the steel pipe 12 can be reduced while reducing costs. Local buckling can be efficiently suppressed.

また、鋼管１２の内部には、長手方向を鋼管１２の軸方向にした縦補強リブ２０と、長手方向を鋼管１２の周方向にした横補強リブ２２とを、適宜組み合わせて配置しても良い。   Further, in the steel pipe 12, a longitudinal reinforcing rib 20 whose longitudinal direction is the axial direction of the steel pipe 12 and a lateral reinforcing rib 22 whose longitudinal direction is the circumferential direction of the steel pipe 12 may be appropriately combined. .

更に、上記実施形態では、鋼管１２として角形鋼管を用いたが、断面多角形の鋼管を用いても良い。更に、図８に示されるように、断面円形形状の丸形鋼管４２を用いても良い。なお、図８に示す構成では、４つの縦補強リブ２０が、その長手方向を鋼管１２の軸方向にして鋼管１２の内部に配置されている。また、鋼管として丸形鋼管を用いた場合は、丸形鋼管の側壁（の内面）に沿って、丸形鋼管の軸方向、丸形鋼管の周方向、又は丸形鋼管の中心軸を中心として螺旋状に延びる鉄筋等を設けても良い。更には、鋼管として、帯鋼を螺旋状に巻いて形成したスパイラル鋼管を用いた場合は、隣接する帯鋼の継目端部を溶接する溶接ビードをスパイラル鋼管の内面側に設けると共に、溶接ビードの厚みを増して、スパイラル鋼管と充填コンクリートの一体性を高めても良い。   Furthermore, in the said embodiment, although the square steel pipe was used as the steel pipe 12, you may use the steel pipe of a cross-sectional polygon. Furthermore, as shown in FIG. 8, a round steel pipe 42 having a circular cross section may be used. In the configuration shown in FIG. 8, the four vertical reinforcing ribs 20 are arranged inside the steel pipe 12 with the longitudinal direction thereof being the axial direction of the steel pipe 12. When a round steel pipe is used as the steel pipe, the axial direction of the round steel pipe, the circumferential direction of the round steel pipe, or the central axis of the round steel pipe along the side wall (inner surface) of the round steel pipe You may provide the reinforcing bar etc. which extend in a spiral. Further, when a spiral steel pipe formed by spirally winding a steel strip is used as the steel pipe, a weld bead for welding the joint end of the adjacent steel strip is provided on the inner surface side of the spiral steel pipe, The thickness may be increased to improve the integrity of the spiral steel pipe and the filled concrete.

また、上記実施形態では、補強部材としての縦補強リブ２０の幅方向の一端部２０Ａを鋼管１２の側壁１２Ａに、縦補強リブ２０の全長に渡って連続溶接で接合したが、縦補強リブ２０の全長に渡って溶接部と非溶接部とが交互に存在する断続溶接で接合しても良い。なお、この断続溶接には、縦補強リブ２０と鋼管１２の側壁１２Ａとの一部を溶接する点溶接は含まれない。前述した各種の変形例についても同様である。   Moreover, in the said embodiment, although the end part 20A of the width direction of the longitudinal reinforcement rib 20 as a reinforcement member was joined to the side wall 12A of the steel pipe 12 by continuous welding over the full length of the longitudinal reinforcement rib 20, the longitudinal reinforcement rib 20 You may join by the intermittent welding in which a welding part and a non-welding part exist alternately over the full length. The intermittent welding does not include spot welding in which a part of the longitudinal reinforcing rib 20 and the side wall 12A of the steel pipe 12 is welded. The same applies to the various modifications described above.

また、上記実施形態におけるコンクリート充填鋼管柱１０には、必要に応じて耐火被覆を施しても良い。   Moreover, you may give fireproof coating to the concrete filling steel pipe column 10 in the said embodiment as needed.

以上、本発明の一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、上記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。   As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to such an embodiment, and the above embodiment and various modifications may be used in combination as appropriate, and the gist of the present invention will be described. Of course, various embodiments can be implemented without departing from the scope.

次に、耐火試験について説明する。   Next, the fire resistance test will be described.

本耐火試験では、高層建物や超高層建物等の高い強度（例えば、設計基準強度で６０Ｎ／ｍｍ２以上、軸力比（軸力／（柱の水平断面積×充填コンクリートの設計基準強度）で０．３以上の高い軸力）が求められるコンクリート充填鋼管柱において、鋼管１２の内部に充填される充填コンクリート１４の骨材が、耐火性能に与える影響を検証した。充填コンクリート１４の骨材としては、従来から一般的に用いられている硬質砂岩骨材と、近年、広く用いられるようになってきた石灰岩骨材を用いた。 In this fire resistance test, high strength of high-rise buildings and ultra-high-rise buildings (for example, 60N / mm 2 or more in design standard strength, axial force ratio (axial force / (horizontal cross-sectional area of column x design standard strength of filled concrete)) In a concrete-filled steel pipe column that requires a high axial force of 0.3 or more, the effect of the aggregate of the filled concrete 14 filled in the steel pipe 12 on the fire resistance performance was verified. Used hard sandstone aggregates that have been generally used, and limestone aggregates that have become widely used in recent years.

耐火試験では、２つの試験体１，２に鉛直荷重（軸力比＝０．４）を載荷しながら、試験体１，２をバーナーで加熱し、各試験体１，２の軸方向の変形量をそれぞれ測定した。試験体１は、石灰岩骨材を用いたコンクリートを角形鋼管に一律に充填した従来のコンクリート充填鋼管柱であり、試験体２では、硬質砂岩骨材を用いたコンクリートを角形鋼管に一律に充填した従来のコンクリート充填鋼管柱である。また、試験体１，２における角形鋼管の水平断面積は同一であり、これらの角形鋼管に充填されるコンクリートのコンクリート強度も略同一（呼び強度５５Ｎ／ｍｍ２、試験時強度７０Ｎ／ｍｍ２程度）である。 In the fire resistance test, a vertical load (axial force ratio = 0.4) is loaded on the two test bodies 1 and 2, and the test bodies 1 and 2 are heated with a burner to deform the test bodies 1 and 2 in the axial direction. Each amount was measured. Specimen 1 is a conventional concrete-filled steel pipe column in which square steel pipe is uniformly filled with concrete using limestone aggregate. In test specimen 2, concrete using hard sandstone aggregate is uniformly filled into square steel pipe. It is a conventional concrete-filled steel pipe column. Moreover, the horizontal cross-sectional areas of the square steel pipes in the test bodies 1 and 2 are the same, and the concrete strength of the concrete filled in these square steel pipes is also substantially the same (nominal strength 55 N / mm 2 , test strength 70 N / mm 2 or so) ).

図９には、耐火試験の試験結果が示されている。図中に実線で示す曲線は試験体１の試験結果であり、点線で示す曲線は試験体２の試験結果である。なお、図９における横軸は加熱時間（分）であり、縦軸は試験体１，２の軸方向の変形量（ｍｍ）である。この変形量（ｍｍ）は、各試験体１，２に鉛直荷重を載荷した状態をゼロとし、軸方向に伸びる方向を正、軸方向に縮む方向を負としている。   FIG. 9 shows the test results of the fire resistance test. In the figure, the curve indicated by the solid line is the test result of the test body 1, and the curve indicated by the dotted line is the test result of the test body 2. In FIG. 9, the horizontal axis represents the heating time (minutes), and the vertical axis represents the axial deformation amount (mm) of the test bodies 1 and 2. The amount of deformation (mm) is zero when a vertical load is loaded on each of the test bodies 1 and 2, positive in the direction extending in the axial direction and negative in the direction contracting in the axial direction.

図９に示される試験結果から、石灰岩骨材を用いた試験体１は、硬質砂岩骨材を用いた試験体２よりも早期に軸方向の変形量（縮み量）が大きくなり、急激に耐力が低下したことが分かる。これは、石灰岩骨材を用いた試験体１では、充填コンクリートの外周部が早期に熱劣化し、鋼管の側壁に局部座屈が発生したためと考えられる。石灰岩骨材を用いたコンクリートは、硬質砂岩骨材を用いたコンクリートに比べ耐火性能が劣ることが知られている。試験体１は加熱によって熱劣化し、脆くなった鋼管周辺のコンクリートが、図３に示す鋼管の面外への変形を抑えることができなくなり、局部座屈によって脆性的に崩壊したものと思われる。このように負担軸力が大きいＣＦＴ柱（例えば軸力比０．３以上）に石灰岩のように脆い骨材を用いる場合は、充填コンクリートが十分な耐力を残している場合でも、鋼管の局部座屈によって早期に破壊が生じる。なお、骨材として安山岩、流紋岩を用いたコンクリートは、硬質砂岩骨材を用いたコンクリートと同等以上の耐火性能を有することが知られている。従って、石灰岩骨材を用いたコンクリートは、安山岩、流紋岩を用いたコンクリートよりも早期に熱劣化するが分かる。   From the test results shown in FIG. 9, the test body 1 using limestone aggregate has a greater amount of axial deformation (shrinkage) at an earlier stage than the test body 2 using hard sandstone aggregate, and the yield strength is rapidly increased. It can be seen that decreased. This is considered to be because in the test body 1 using limestone aggregate, the outer peripheral portion of the filled concrete was thermally deteriorated early and local buckling occurred on the side wall of the steel pipe. It is known that concrete using limestone aggregate is inferior in fire resistance performance to concrete using hard sandstone aggregate. It seems that the test body 1 was thermally deteriorated by heating, and the concrete around the steel pipe that became brittle could not suppress the deformation of the steel pipe shown in FIG. 3 out of plane, and collapsed brittlely due to local buckling. . When brittle aggregates such as limestone are used for CFT columns with a large axial load (for example, axial force ratio of 0.3 or more), local seats of steel pipes are used even when the filled concrete has sufficient proof stress. Destruction occurs early due to bending. In addition, it is known that concrete using andesite and rhyolite as aggregate has fire resistance performance equal to or higher than concrete using hard sandstone aggregate. Therefore, it can be seen that the concrete using limestone aggregate deteriorates more quickly than the concrete using andesite and rhyolite.

一方、石灰岩は、硬質砂岩、安山岩、流紋岩等と比較して安価で、かつコンクリート強度の高強度化（設計基準強度で８０Ｎ／ｍｍ２程度まで）が可能であり、近年、広く用いられるようになっている。従って、上記実施形態及び各種の変形例は、前述した高い強度が求められ、かつ、充填コンクリートの骨材として石灰岩が用いられたコンクリート充填鋼管柱に特に有効であり、このようなコンクリート充填鋼管柱に上記実施形態及び各種の変形例を適用することで、コスト削減を図りつつ、コンクリート充填鋼管柱の耐火性能を飛躍的に向上させることができる。 On the other hand, limestone is cheaper than hard sandstone, andesite, rhyolite, etc., and can increase the strength of concrete (up to about 80 N / mm 2 in design standard strength), and has been widely used in recent years. It is like that. Therefore, the above embodiment and various modifications are particularly effective for the concrete-filled steel pipe column in which the above-described high strength is required and limestone is used as the aggregate of the filled concrete. By applying the above embodiment and various modifications to the above, it is possible to drastically improve the fire resistance of the concrete-filled steel pipe column while reducing costs.

なお、上記実施形態及び各種の変形例は、充填コンクリートの骨材として硬質砂岩、安山岩、流紋岩等を用いたコンクリート充填鋼管柱や、一般的な強度のコンクリート充填鋼管柱にも、当然ながら適用可能である。   In addition, the said embodiment and various modifications are naturally also applied to concrete-filled steel pipe columns using hard sandstone, andesite, rhyolite as aggregates of filled concrete, and concrete-filled steel pipe columns of general strength. Applicable.

１０ コンクリート充填鋼管柱
１２ 鋼管
１２Ａ 側壁
１４ 充填コンクリート
２０ 縦補強リブ（補強部材、補強リブ）
２２ 横補強リブ（補強部材、補強リブ）
２４ 縦補強部材（補強部材）
２４Ｗ ウェブ部（補強リブ）
２４Ｆ フランジ部
２６ 縦補強部材（補強部材）
２６Ｗ ウェブ部（補強リブ）
２６Ｆ２ フランジ部
２８ 棒状部材（補強部材）
３０ 棒状部材（補強部材）
４２ 丸形鋼管（鋼管）
４２Ａ 側壁 DESCRIPTION OF SYMBOLS 10 Concrete filled steel pipe pillar 12 Steel pipe 12A Side wall 14 Filled concrete 20 Vertical reinforcement rib (reinforcement member, reinforcement rib)
22 Lateral reinforcing ribs (reinforcing members, reinforcing ribs)
24 Longitudinal reinforcement member (reinforcement member)
24W web part (reinforcing rib)
24F Flange portion 26 Vertical reinforcing member (reinforcing member)
26W web part (reinforcing rib)
26F2 Flange 28 Bar-shaped member (reinforcing member)
30 Bar-shaped member (reinforcing member)
42 Round steel pipe (steel pipe)
42A side wall

Claims (3)

鋼管と、
前記鋼管の内部に、長手方向を前記鋼管の軸方向又は周方向にして配置されると共に、長手方向に沿って該鋼管の側壁に接合され、該側壁から突出する補強部材と、
前記鋼管に充填される充填コンクリートと、
を備えるコンクリート充填鋼管柱。 Steel pipes,
Inside the steel pipe, the longitudinal direction is arranged in the axial direction or the circumferential direction of the steel pipe, and the reinforcing member is joined to the side wall of the steel pipe along the longitudinal direction and protrudes from the side wall;
Filled concrete filled in the steel pipe;
Concrete-filled steel pipe column with. 前記補強部材が、板状の補強リブであり、
前記補強リブの先端部にフランジ部が設けられている請求項１に記載のコンクリート充填鋼管柱。 The reinforcing member is a plate-shaped reinforcing rib;
The concrete-filled steel pipe column according to claim 1, wherein a flange portion is provided at a tip portion of the reinforcing rib. 前記補強部材が、前記鋼管の側壁に連続溶接又は断続溶接で接合されている請求項１又は請求項２に記載のコンクリート充填鋼管柱。   The concrete-filled steel pipe column according to claim 1 or 2, wherein the reinforcing member is joined to a side wall of the steel pipe by continuous welding or intermittent welding.
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CN109989519A (en) * 2019-05-09 2019-07-09 中国建筑第七工程局有限公司 A ribbed steel concrete member
CN111593846A (en) * 2020-06-22 2020-08-28 宁波优造建筑科技有限公司 A high-strength thin-walled steel tube concrete composite column
CN111980157A (en) * 2020-08-26 2020-11-24 长安大学 Open steel pipe concrete structure with cold-bending turned edge and batten plate
CN112160502A (en) * 2020-09-18 2021-01-01 北京工业大学 Corrugated plate connected steel special-shaped column
CN113530084A (en) * 2021-08-07 2021-10-22 华东交通大学 Steel pipe concrete column with T-shaped stiffening rib on inner side of steel pipe
CN115217270A (en) * 2021-04-20 2022-10-21 中国建筑设计研究院有限公司 A large-diameter built-in vertical rib circular steel tubular concrete column and preparation method thereof
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KR20180008946A (en) * 2016-07-14 2018-01-25 주식회사 포스코 Steel tube and composite column using the same
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WO2018072777A1 (en) 2016-10-17 2018-04-26 Burkhart Schurig Wall construction system for building houses, having dry construction composite columns of structural steel and concrete
US10655327B2 (en) 2016-10-17 2020-05-19 Burkhart Schurig Wall construction system with drywall composite columns and method for wall construction
CN107663926B (en) * 2017-09-29 2023-09-15 浙江省建工集团有限责任公司 L-shaped steel tube concrete composite column
CN107663926A (en) * 2017-09-29 2018-02-06 浙江省建工集团有限责任公司 A kind of L-shaped concrete filled steel tube coupled column
CN109057160A (en) * 2018-09-10 2018-12-21 李新华 Polygon steel pipe concrete column
CN109989519A (en) * 2019-05-09 2019-07-09 中国建筑第七工程局有限公司 A ribbed steel concrete member
CN111593846A (en) * 2020-06-22 2020-08-28 宁波优造建筑科技有限公司 A high-strength thin-walled steel tube concrete composite column
CN111980157A (en) * 2020-08-26 2020-11-24 长安大学 Open steel pipe concrete structure with cold-bending turned edge and batten plate
CN112160502A (en) * 2020-09-18 2021-01-01 北京工业大学 Corrugated plate connected steel special-shaped column
CN115217270A (en) * 2021-04-20 2022-10-21 中国建筑设计研究院有限公司 A large-diameter built-in vertical rib circular steel tubular concrete column and preparation method thereof
CN115217270B (en) * 2021-04-20 2023-06-13 中国建筑设计研究院有限公司 A large-diameter built-in vertical rib circular concrete column and its preparation method
CN113530084A (en) * 2021-08-07 2021-10-22 华东交通大学 Steel pipe concrete column with T-shaped stiffening rib on inner side of steel pipe
KR20230095360A (en) 2021-12-22 2023-06-29 주식회사 포스코 Composite column and manufacturing method thereof

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