JP2017203378A - Reinforcement structure for reinforced-concrete wall pillar and reinforcement structure for reinforced-concrete beam member - Google Patents

Reinforcement structure for reinforced-concrete wall pillar and reinforcement structure for reinforced-concrete beam member Download PDF

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JP2017203378A
JP2017203378A JP2017164091A JP2017164091A JP2017203378A JP 2017203378 A JP2017203378 A JP 2017203378A JP 2017164091 A JP2017164091 A JP 2017164091A JP 2017164091 A JP2017164091 A JP 2017164091A JP 2017203378 A JP2017203378 A JP 2017203378A
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shear
reinforcement
bars
reinforcing
bar
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JP6513754B2 (en
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健好 是永
Takeyoshi Korenaga
健好 是永
慎一郎 河本
Shinichiro Kawamoto
慎一郎 河本
努 小室
Tsutomu Komuro
努 小室
洋三 篠崎
Yozo Shinozaki
洋三 篠崎
宮原 貴昭
Takaaki Miyahara
貴昭 宮原
英義 渡辺
Hideyoshi Watanabe
英義 渡辺
智昭 杉山
Tomoaki Sugiyama
智昭 杉山
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Taisei Corp
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Taisei Corp
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Abstract

PROBLEM TO BE SOLVED: To achieve shear reinforcing bars by securing cover concrete and using thick-diameter reinforcing bars at regions with severe stress conditions without deteriorating workability.SOLUTION: The reinforcement structure for a reinforced-concrete member comprises first shear reinforcing bars arranged on an outer peripheral side of longitudinal bars of the reinforced-concrete member, and second shear reinforcing bars linearly extended across columns of the mutually-facing longitudinal bars at an inner peripheral side of the longitudinal bars, the second shear reinforcing bars having a larger diameter than that of the first shear reinforcing bars, and also comprising plate type fixing parts, located at the outer peripheral side of the longitudinal bars, at both end parts thereof.SELECTED DRAWING: Figure 1

Description

本発明は鉄筋コンクリート部材のせん断補強技術に関する。   The present invention relates to a shear reinforcement technique for reinforced concrete members.

鉄筋コンクリート部材(以下、RC部材ともいう)のせん断補強技術としては様々な方式が提案されている。例えば、特許文献1には開口部(貫通孔)を有する梁のせん断補強技術が開示されている。特許文献2には、壁柱(扁平柱)内にせん断補強筋を交差させたものが開示されている。また、特許文献3には中子筋を用いたものが開示されている。   Various methods have been proposed for shear reinforcement of reinforced concrete members (hereinafter also referred to as RC members). For example, Patent Document 1 discloses a technique for shear reinforcement of a beam having an opening (through hole). Patent Document 2 discloses a structure in which shear reinforcement bars are crossed in a wall column (flat column). Further, Patent Document 3 discloses one using a core muscle.

RC部材のせん断補強は、一般にD10〜D16の細径鉄筋を使って主筋を囲むようになされている(フープ、スターラップ)。また、超高強度鉄筋(例えばSBPD1275/1420)を使用する場合には、せん断補強筋の径が更に小さくなる場合(公称径7.1mm、9.0mm)もある。長方形断面のRC部材のせん断補強としては、せん断応力条件が厳しい部材端部付近に、せん断補強筋を密に配筋することも知られている。   In general, RC members are reinforced by using D10 to D16 thin reinforcing bars to surround the main bars (hoops, stirrups). In addition, when using an ultra-high strength reinforcing bar (for example, SBPD1275 / 1420), the diameter of the shear reinforcing bar may be further reduced (nominal diameters 7.1 mm and 9.0 mm). As a shear reinforcement of RC members having a rectangular cross section, it is also known that a shear reinforcement bar is densely arranged near the end of a member having severe shear stress conditions.

一方、このような長方形断面部材、特に断面の長辺/短辺比が大きい扁平な壁柱や壁梁(ウォールガーダー)では、主筋による曲げ抵抗力に対して圧縮部コンクリートの幅が狭い。このため、例えば図7(A)に示すような最終ひび割れ状態となり、正方形断面の部材などに比べて部材端圧縮部コンクリートの圧壊が生じやすい。また、開口部(貫通孔)を有する梁部材では、開口補強がない場合には図7(B)に示すように開口部から伸びるせん断ひび割れが拡大する破壊形式となり、十分な開口補強を施していても図7(C)に示すように開口部上下でせん断ひび割れが拡大する破壊形式となりえる。   On the other hand, in such a rectangular cross-section member, in particular, a flat wall column or wall beam (wall girder) having a large long side / short side ratio, the width of the compressed concrete is narrow with respect to the bending resistance force by the main bars. For this reason, it will be in the final crack state as shown, for example in FIG. 7 (A), and it will be easy to produce crushing of member end compression part concrete compared with the member of a square cross section. Further, in the case of a beam member having an opening (through hole), when there is no opening reinforcement, as shown in FIG. 7 (B), a shearing crack extending from the opening is expanded, and sufficient opening reinforcement is applied. However, as shown in FIG. 7C, it can be a fracture type in which shear cracks expand above and below the opening.

特開2011−256658号公報JP 2011-256658 A 特開2002−4411号公報Japanese Patent Laid-Open No. 2002-4411 特開平8−260565号公報JP-A-8-260565

図7(A)〜(C)に示したような、部材の曲げ補強部の主筋位置近傍におけるひび割れの拡大を抑止する方策として、例えば、外周のせん断補強筋とは別に、太径の鉄筋を使った中子筋を設けることが考えられる。しかし、図8(A)に示すように、鉄筋の曲げ半径およびフック部の余長に関する配筋規定により、曲げ加工されたフック部における鉄筋の曲げ半径や余長が大きくなり、配筋困難な場合がある。なお、同図のような135°フックではなく、180°フックを採用すると余長が短くなって施工は煩雑であるが配筋が可能となる場合が増える。しかし、同図に示すように中子筋の直線部(S2)では引張力が有効に働くものの、それ以外の部分(S1)では引張力の利きが悪くなる。よって、主筋近傍の破壊を誘発するひび割れの伸展・拡大を効率的に拘束できない。   As a measure for suppressing the expansion of cracks in the vicinity of the main reinforcing bar position of the bending reinforcement portion of the member as shown in FIGS. 7 (A) to (C), for example, a large diameter reinforcing bar is used separately from the outer peripheral shear reinforcing bar. It is conceivable to provide the core muscle used. However, as shown in FIG. 8 (A), due to the reinforcement arrangement relating to the bending radius of the reinforcing bar and the extra length of the hook part, the bending radius and extra length of the reinforcing bar in the bent hook part are increased, making it difficult to arrange the reinforcing bar. There is a case. If the 180 ° hook is used instead of the 135 ° hook as shown in the figure, the extra length is shortened and the construction is complicated, but the number of cases where the bar arrangement is possible increases. However, as shown in the figure, although the tensile force works effectively in the straight portion (S2) of the core muscle, the other portion (S1) has poor tensile force. Therefore, the extension / expansion of a crack that induces destruction near the main muscle cannot be efficiently restrained.

また、フープ、スターラップに太径の鉄筋を使用することや、一般的な細径鉄筋(D10〜D16)を使ってせん断補強筋(フープ、スターラップ)を密に配筋することも考えられる。しかし、いずれの方策も施工面での困難性や限界がある。また、一般論として、柱、梁や壁等のせん断補強筋量を増やしても、その効果には限界があると言われている。   It is also possible to use large-diameter rebars for hoops and stirrups, and to densely arrange shear reinforcement bars (hoops and stirrups) using general thin-diameter rebars (D10 to D16). . However, each measure has difficulty and limitations in construction. In general, it is said that there is a limit to the effect of increasing the amount of shear reinforcement such as columns, beams and walls.

その要因の一つが、日本建築学会編「(旧)鉄筋コンクリート構造計算規準・同解説」(以下、旧RC規準)の耐震壁に関する解説に示されている。図8(B)は同規準で示される模式図である。同解説では、せん断ひび割れ面に対して45°にせん断補強筋が横切っているため、図に示すようにひび割れ幅の拡大(またはひび割れ面でのずれ)によってせん断補強筋が曲がろうとし、その屈曲部のコンクリートが圧縮され、かぶり厚に対して太い径の鉄筋を使用した場合や、細径鉄筋で補強筋量を増やした場合には、屈曲部のコンクリートが局所的に破壊し、せん断補強筋の引張力があまり増大せず、補強効果が十分期待できないことが指摘されている。     One of the factors is shown in the commentary on earthquake-resistant walls in “(Old) Reinforced Concrete Structure Calculation Standards / Description” (hereinafter referred to as the former RC Standard) edited by the Architectural Institute of Japan. FIG. 8B is a schematic diagram shown in the same standard. In this explanation, since the shear reinforcement crosses at 45 ° with respect to the shear crack surface, the shear reinforcement attempts to bend by expanding the crack width (or displacement on the crack surface) as shown in the figure. If the concrete in the bent part is compressed and a reinforcing bar with a diameter larger than the cover thickness is used, or if the reinforcing bar is increased with a small diameter reinforcing bar, the concrete in the bent part will be locally destroyed and shear reinforcement will occur. It has been pointed out that the tensile force of the muscle does not increase so much and the reinforcing effect cannot be expected sufficiently.

したがって、太径鉄筋に対して十分なかぶりを確保した補強方法が肝要と考えられる。この点は、一般のRC部材のせん断補強において、前述した中子筋を除き、せん断補強筋は断面外周に施されてかぶりが少ないこと、コンクリート強度が大きくなるとせん断補強筋の効果が増大するという既往の研究事例とも関係する。   Therefore, it is considered that a reinforcing method that ensures a sufficient cover for large-diameter reinforcing bars is essential. This point is that, in the shear reinforcement of general RC members, except for the above-described core reinforcing bars, the shear reinforcing bars are applied to the outer periphery of the cross section and there is little fogging, and the effect of the shear reinforcing bars increases as the concrete strength increases. It is also related to previous research cases.

一方、別の要因として、RC部材のせん断抵抗機構として現行の設計で普及しているトラス機構では、せん断補強筋の引張力、斜め方向に形成されるコンクリート圧縮束の圧縮力、および主筋の付着力の3つの内力の釣合条件により、せん断抵抗力が決まり、せん断補強量が多いとコンクリート圧縮束がクリティカル(せん断圧縮破壊)となり、せん断補強筋が降伏せずにせん断抵抗力が頭打ちとなることがよく知られている。ただし、図8(B)で示したひび割れ幅の拡大を抑止する効果は、十分なかぶりを有する太径鉄筋の方が鉄筋の曲げ剛性(鉄筋の断面2次モーメント)が大きくひび割れ面で変形しづらく、少なくともトラス機構で想定さるせん断補強筋の効果に比べて抵抗力が増大すると考えられる。     On the other hand, as another factor, in the truss mechanism that is popular in the current design as the shear resistance mechanism of RC members, the tensile force of the shear reinforcement, the compressive force of the concrete compression bundle formed in the diagonal direction, and the attachment of the main reinforcement The shear resistance is determined by the balance condition of the three internal forces, and if the amount of shear reinforcement is large, the concrete compression bundle becomes critical (shear compression failure), and the shear reinforcement does not yield and the shear resistance reaches a peak. It is well known. However, the effect of suppressing the expansion of the crack width shown in Fig. 8 (B) is that the large-diameter rebar with sufficient cover has a greater bending rigidity (secondary moment of rebar cross section) of the rebar and deforms on the crack surface. It is considered that resistance is increased compared to at least the effect of the shear reinforcement assumed by the truss mechanism.

本発明の目的は、かぶりを確保するとともに施工性を悪化させることなく、応力条件が厳しい部位へ、より太径の鉄筋を利用してそのせん断補強を行うことにある。     An object of the present invention is to perform shear reinforcement using a thicker reinforcing bar to a part where the stress condition is severe without securing the fog and degrading the workability.

本発明によれば、鉄筋コンクリート部材の補強構造であって、前記鉄筋コンクリート部材の主筋の外周側に配設された第1のせん断補強筋と、前記主筋の内周側において、互いに対向する前記主筋の列を横断するように直線的に延設された第2のせん断補強筋と、を備え、前記第2のせん断補強筋は、前記第1のせん断補強筋よりも太径であり、かつ、その両端部に、前記主筋の外周側に位置するプレート型定着部を備えることを特徴とする補強構造が提供される。     According to the present invention, there is provided a reinforcing structure for a reinforced concrete member, wherein the first shear reinforcing bar disposed on the outer peripheral side of the main reinforcing bar of the reinforced concrete member and the main reinforcing bar facing each other on the inner peripheral side of the main reinforcing bar. A second shear reinforcement bar extending linearly across the row, the second shear reinforcement bar being thicker than the first shear reinforcement bar, and There is provided a reinforcing structure characterized in that plate-type fixing portions are provided at both ends on the outer peripheral side of the main bar.

本発明によれば、かぶりを確保するとともに施工性を悪化させることなく、応力条件が厳しい部位へ、より太径の鉄筋を利用してそのせん断補強を行うことができる。     According to the present invention, it is possible to perform shear reinforcement using a thicker reinforcing bar to a part where the stress condition is severe without securing the fog and deteriorating the workability.

(A)は本発明の一実施形態に係る補強構造を適用した扁平柱の垂直断面図、(B)は水平断面図。(A) is a vertical sectional view of a flat column to which a reinforcing structure according to an embodiment of the present invention is applied, and (B) is a horizontal sectional view. (A)は別例の補強構造を適用した扁平柱の垂直断面図、(B)は水平断面図、(C)は図2(A)の線I−Iに沿う断面図。(A) is a vertical cross-sectional view of a flat column to which another reinforcing structure is applied, (B) is a horizontal cross-sectional view, and (C) is a cross-sectional view taken along line II in FIG. 2 (A). (A)及び(B)は、それぞれ別例の補強構造を適用した扁平柱の水平断面図。(A) And (B) is a horizontal sectional view of the flat pillar to which the reinforcement structure of another example was applied, respectively. (A)は本発明の一実施形態に係る補強構造を適用した梁の水平断面図、(B)は垂直断面図、(C)は図4(B)の線II−IIに沿う断面図。(A) is a horizontal sectional view of a beam to which a reinforcing structure according to an embodiment of the present invention is applied, (B) is a vertical sectional view, and (C) is a sectional view taken along line II-II in FIG. 4 (B). 別例の補強構造を適用した梁の垂直断面図。The vertical sectional view of the beam which applied the reinforcement structure of another example. ひび割れ集中率と断面欠損率とを示す図。The figure which shows a crack concentration rate and a cross-sectional defect rate. (A)は扁平柱におけるひび割れ状態の説明図、(B)及び(C)は開口部を有する梁におけるひび割れ状態の説明図。(A) is explanatory drawing of the crack state in a flat column, (B) and (C) are explanatory drawings of the crack state in the beam which has an opening part. (A)は中子筋の問題点の説明図、(B)は従来のせん断補強の問題点の説明図。(A) is explanatory drawing of the problem of a core line, (B) is explanatory drawing of the problem of the conventional shear reinforcement.

<第1実施形態>
図1(A)は本発明の一実施形態に係る補強構造を適用したRC部材である、扁平柱(壁柱)1の垂直断面図であり、扁平柱1の立面図を示している。図1(B)は扁平柱1の水平断面図である。なお、各図に示す矢印X、Yは互いに直交する水平方向を示し、矢印Zは上下方向(垂直方向)を示している。
<First Embodiment>
FIG. 1A is a vertical sectional view of a flat column (wall column) 1, which is an RC member to which a reinforcing structure according to an embodiment of the present invention is applied, and shows an elevation view of the flat column 1. FIG. 1B is a horizontal sectional view of the flat column 1. In the drawings, arrows X and Y indicate horizontal directions orthogonal to each other, and an arrow Z indicates a vertical direction (vertical direction).

扁平柱1は長方形断面のRC部材であり、その長辺方向がX方向であり、その短辺方向がY方向となっている。長辺方向を左右方向と呼び、短辺方向を奥行方向と呼ぶ場合がある。扁平柱1は主筋2a及び2b(総称するときは主筋2という)、補助筋3、拘束筋4、中子筋5、せん断補強筋6及びせん断補強筋7を備える。せん断補強筋6及びせん断補強筋7は本発明の一実施形態に係る補強構造を構成している。     The flat column 1 is an RC member having a rectangular cross section, the long side direction is the X direction, and the short side direction is the Y direction. The long side direction may be referred to as the left-right direction, and the short side direction may be referred to as the depth direction. The flat column 1 includes main bars 2a and 2b (referred to collectively as main bar 2), auxiliary bars 3, restraint bars 4, core bars 5, shear reinforcement bars 6 and shear reinforcement bars 7. The shear reinforcement bar 6 and the shear reinforcement bar 7 constitute a reinforcement structure according to an embodiment of the present invention.

曲げ補強筋となる主筋2は、面内方向(X方向)に対して働く比較的太径の集約主筋としており、配置上、左隅部の主筋2aと、右隅部の主筋2bとに大別される。図1(B)に示すように、全主筋2を囲む包絡線Lの内側を内周側、外側を外周側と呼ぶ。主筋2はZ方向に延設されており、左隅部の主筋2a及び右隅部の主筋2bのいずれも、Y方向を列方向として1列2本の構成であり、2列で4本、総計で8本とされている。左隅部の主筋2aと、右隅部の主筋2bとは、互いに対向する主筋の列を構成している。     The main reinforcement 2 serving as a bending reinforcement is an aggregated main reinforcement having a relatively large diameter that works in the in-plane direction (X direction), and is roughly divided into a main reinforcement 2a at the left corner and a main reinforcement 2b at the right corner. Is done. As shown in FIG. 1B, the inner side of the envelope L surrounding all the main muscles 2 is called the inner peripheral side, and the outer side is called the outer peripheral side. The main bar 2 extends in the Z direction, and both the main bar 2a at the left corner and the main bar 2b at the right corner have a configuration of two in one row with the Y direction as the column direction. It is said to be eight. The main bar 2a at the left corner and the main bar 2b at the right corner constitute a row of main bars facing each other.

補助筋3はZ方向に延設され、扁平柱1の部材周縁に沿って複数本(ここでは20本)配筋されている。拘束筋4は、左隅部の主筋2aと、右隅部の主筋2bとに区分けされてその周辺の補助筋3を囲むように配設されている。中子筋5は扁平柱1のX方向中央部において、両端部が補助筋3に係止されて配筋されている。     The auxiliary bars 3 extend in the Z direction, and a plurality of bars (here, 20 bars) are arranged along the peripheral edge of the flat column 1. The restraint muscle 4 is divided into a main muscle 2a at the left corner and a main muscle 2b at the right corner, and is disposed so as to surround the auxiliary muscle 3 in the vicinity thereof. The core muscle 5 is arranged with both ends locked to the auxiliary muscle 3 at the center in the X direction of the flat column 1.

せん断補強筋6は、主筋2の外周側に配置され、本実施形態の場合、補助筋3を囲むように環状を有して配置されたフープを構成している。せん断補強筋6としては、例えば、D10〜D16の細径鉄筋を採用できる。     The shear reinforcement bar 6 is arranged on the outer peripheral side of the main bar 2, and forms a hoop having a ring shape so as to surround the auxiliary bar 3 in the case of the present embodiment. As the shear reinforcement 6, for example, D10 to D16 small-diameter reinforcing bars can be adopted.

せん断補強筋7は、主筋2の内周側において、互いに対向する主筋2aの列と主筋2bの列とを横断するようにX方向に直線的に延設されている。せん断補強筋7は、せん断補強筋6よりも太径とした棒状鉄筋であり、Z方向でみるとせん断補強筋6と交互に配置されている。本実施形態の場合、せん断補強筋7はY方向中央部において1列配置された構成としている。しかし、複数列配置(例えば部材幅に応じて最大4列程度)でもよい。     The shear reinforcement bars 7 are linearly extended in the X direction so as to cross the rows of the main bars 2a and the main bars 2b facing each other on the inner peripheral side of the main bar 2. The shear reinforcement bars 7 are rod-like reinforcing bars having a diameter larger than that of the shear reinforcement bars 6 and are alternately arranged with the shear reinforcement bars 6 when viewed in the Z direction. In the case of the present embodiment, the shear reinforcement bars 7 are arranged in a single row at the center in the Y direction. However, it may be arranged in a plurality of rows (for example, up to about 4 rows depending on the member width).

せん断補強筋7の両端部にはプレート型定着部7a、7aが設けられている。プレート型定着部7aは、せん断補強筋7の径方向に突出してせん断補強筋7端部の定着性を向上できる構成であればどのような構成でもよい。例えば、せん断補強筋7の途中部に対して拡径したもの、鋼板を固定したもの、定着板を有するナットを装着したもの等とすることができる。鋼板を用いる場合は、例えば、せん断補強筋7を構成する鉄筋端部に摩擦圧接で固着してもよい。プレート型定着部7aは主筋2の外周側に配置されている。     Plate-type fixing portions 7 a and 7 a are provided at both ends of the shear reinforcement 7. The plate-type fixing unit 7a may have any configuration as long as it projects in the radial direction of the shear reinforcing bar 7 and can improve the fixing property of the end of the shear reinforcing bar 7. For example, the diameter of the shear reinforcing bar 7 can be increased, the steel plate can be fixed, the nut having a fixing plate can be attached, and the like. In the case of using a steel plate, for example, it may be fixed to the end of the reinforcing bar constituting the shear reinforcing bar 7 by friction welding. The plate-type fixing unit 7 a is disposed on the outer peripheral side of the main bar 2.

本実施形態の場合、プレート型定着部7aを補助筋3に引っ掛けるように配置している。この構成はせん断補強筋7に引っ張り力が作用した場合にせん断補強筋7の定着性を向上させる。引っ掛ける対象は主筋2であってもよい。     In the case of the present embodiment, the plate-type fixing unit 7 a is arranged to be hooked on the auxiliary muscle 3. This configuration improves the fixing property of the shear reinforcement 7 when a tensile force acts on the shear reinforcement 7. The object to be hooked may be the main muscle 2.

係る構成からなる扁平柱1では、せん断力が同図矢印方向に作用した場合に、圧縮部となる柱脚部1aにおいて、太径のせん断補強筋7が圧壊を誘発する主筋位置のひび割れ(破線L1)の拡大を直接拘束する配筋となっており、ひび割れの拡大・伸展を十分抑止できる。     In the flat column 1 having such a structure, when the shearing force acts in the direction of the arrow in the figure, the large-diameter shear reinforcing bar 7 cracks at the main bar position where the large-diameter shear reinforcing bar 7 induces collapse in the column base 1a serving as the compression unit (broken line) It is a reinforcement that directly restrains the expansion of L1), and can sufficiently prevent the expansion and extension of cracks.

太径のせん断補強筋7を採用することにより、多量の細径補強筋で同程度のせん断補強を行った場合に比べて、太径鉄筋の曲げ剛性が大きいため、それを横切るせん断ひび割れの伸展・拡大を抑止できる。例えば、1本の太径鉄筋D29に対して、細径鉄筋D10で鉄筋の総断面積を等しくするためには9本必要(6.42cm2)となる。鉄筋の曲げ剛性、すなわち断面2次モーメント(I=πd4/64、d:鉄筋径)のみで考えると、1本のD29鉄筋は、断面積が等しい9本のD10鉄筋の7.9倍となり、両者の鉄筋屈曲部のコンクリート支圧面の複雑な応力条件の違い等を考慮しても、太径鉄筋を使用することによって、鉄筋の曲げ剛性は確実に大きくなる。     By adopting the large-diameter shear reinforcement bar 7, the bending rigidity of the large-diameter reinforcing bar is larger than that when a large amount of small-diameter reinforcement reinforcement is used.・ Can prevent expansion. For example, in order to make the total cross-sectional area of the reinforcing bar equal with the thin reinforcing bar D10, 9 pieces are required (6.42cm2) for one large reinforcing bar D29. Considering only the bending stiffness of the reinforcing bar, that is, the moment of inertia of the cross section (I = πd4 / 64, d: reinforcing bar diameter) Even in consideration of complicated differences in stress conditions on the concrete bearing surface of the reinforcing bar bending portion, the bending rigidity of the reinforcing bar is reliably increased by using the large diameter reinforcing bar.

このせん断ひび割れ伸展・拡大を抑止する効果は、せん断補強筋7の径ができるだけ大きい方が効果的であり、併用するせん断補強筋6の径より2倍以上太径であることが好ましく、特に、D19以上の鉄筋であることが好ましい。     The effect of suppressing the extension / expansion of shear cracks is effective when the diameter of the shear reinforcing bar 7 is as large as possible, and is preferably at least twice as large as the diameter of the shear reinforcing bar 6 used together. It is preferably a D19 or higher reinforcing bar.

せん断補強筋7は直線の棒状鉄筋であり、曲げ加工を要しないので太径としても施工性を悪化させない。更に、その両端部にプレート型定着部7aを設けたので、定着性を向上できるだけでなく、かぶりがプレート型定着部7aの厚みには影響されるものの、せん断補強筋7の径に影響されず、より太径の鉄筋を利用した場合であっても、かぶりを確保しやすくなっている。     The shear reinforcing bar 7 is a straight bar-shaped reinforcing bar and does not require bending, so that the workability is not deteriorated even if the diameter is large. Further, since the plate-type fixing portions 7a are provided at both ends thereof, not only the fixing property can be improved, but the fogging is influenced by the thickness of the plate-type fixing portion 7a, but is not affected by the diameter of the shear reinforcement bars 7. Even when a thicker reinforcing bar is used, it is easy to ensure the cover.

こうして本実施形態の補強構造では、かぶりを確保するとともに施工性を悪化させることなく、応力条件が厳しい部位(ここでは柱脚部1a)へ、より太径の鉄筋を利用してそのせん断補強を行うことができる。また、配筋方法が簡易かつ合理的なため、終局耐力等の設計法が明快かつ簡便なものとなる。     Thus, in the reinforcing structure of the present embodiment, the shear reinforcement is performed using a thicker reinforcing bar to a part where the stress conditions are severe (here, the column base portion 1a) without securing the covering and degrading the workability. It can be carried out. In addition, since the bar arrangement method is simple and rational, the design method for ultimate strength and the like becomes clear and simple.

なお、本実施形態では、Z方向全域にわたってせん断補強筋7を配置しているが、応力条件が相対的に厳しくない部位(例えば扁平柱1のZ方向中間部位)ではプレート型定着部7aを省略してもよく、あるいは、せん断補強筋7の本数を減らしたり、なくしたりしてもよい。     In the present embodiment, the shear reinforcement bars 7 are arranged over the entire Z direction, but the plate-type fixing unit 7a is omitted in a portion where the stress condition is not relatively strict (for example, the intermediate portion in the Z direction of the flat column 1). Alternatively, the number of the shear reinforcement bars 7 may be reduced or eliminated.

<第2実施形態>
図2(A)は本発明の別実施形態に係る補強構造を適用したRC部材である、扁平柱(壁柱)1Aの垂直断面図であり、扁平柱1の立面図を示している。図2(B)は扁平柱1Aの水平断面図、図2(C)は図2(A)の線II−IIに沿う断面図である。扁平柱1Aは、上記第1実施形態の扁平柱1の変形例であり、同様の構成については同じ符号を付して説明を省略し、異なる点について以下に説明する。
Second Embodiment
FIG. 2A is a vertical sectional view of a flat column (wall column) 1 </ b> A, which is an RC member to which a reinforcing structure according to another embodiment of the present invention is applied, and shows an elevation view of the flat column 1. 2B is a horizontal sectional view of the flat column 1A, and FIG. 2C is a sectional view taken along line II-II in FIG. 2A. The flat column 1A is a modified example of the flat column 1 of the first embodiment. The same components are denoted by the same reference numerals, description thereof is omitted, and different points will be described below.

本実施形態は、上記第1実施形態のせん断補強筋6に対応するせん断補強筋6’を有している。せん断補強筋6’は、主筋2の外周側に配置されているが、直線棒状の鉄筋であり、1段の同一水平面上にY方向に離間して互いに平行に2本設けられている。     This embodiment has a shear reinforcement bar 6 'corresponding to the shear reinforcement bar 6 of the first embodiment. The shear reinforcing bars 6 ′ are arranged on the outer peripheral side of the main reinforcing bars 2, but are straight bar-like reinforcing bars, and are provided in parallel with each other at a distance in the Y direction on the same horizontal plane.

せん断補強筋7は上記第1実施形態と同様であるが、せん断補強筋6’と、せん断補強筋7との配設位置を高さ方向(Z方向)で近接させている。換言すると、せん断補強筋6’とせん断補強筋7とが、主筋2の列方向と平行な方向(Y方向)で互いに重なるように配置されている。本実施形態では、特に、せん断補強筋6’の中心軸の高さとせん断補強筋7の中心軸とを同一水平面(破線L2)上に位置させており、両者のZ方向の位置を揃えた構成としている。そして、せん断補強筋6’とせん断補強筋7の組と、拘束筋4とをZ方向に交互に配置して、両者の干渉を回避する配筋としている。     The shear reinforcement bars 7 are the same as those in the first embodiment, but the arrangement positions of the shear reinforcement bars 6 'and the shear reinforcement bars 7 are close to each other in the height direction (Z direction). In other words, the shear reinforcement bars 6 ′ and the shear reinforcement bars 7 are arranged so as to overlap each other in a direction (Y direction) parallel to the row direction of the main bars 2. In the present embodiment, in particular, the height of the central axis of the shear reinforcement bar 6 ′ and the central axis of the shear reinforcement bar 7 are located on the same horizontal plane (broken line L2), and the positions of both are aligned in the Z direction. It is said. A set of shear reinforcement bars 6 ′ and shear reinforcement bars 7 and restraint bars 4 are alternately arranged in the Z direction so as to avoid the interference between them.

せん断補強筋6’と、せん断補強筋7との配設位置を高さ方向(Z方向)で近接させると、その断面(破線L2)でコンクリート面積が鉄筋によって欠損することになり、作用せん断力によって発生する曲げひび割れが破線L2に沿って伸展しやすくなる。     If the arrangement positions of the shear reinforcement bars 6 'and the shear reinforcement bars 7 are close to each other in the height direction (Z direction), the concrete area will be lost by the reinforcing bars in the cross section (broken line L2), and the acting shear force The bending crack generated by the above becomes easier to extend along the broken line L2.

一方、せん断補強筋7が太径であればあるほど曲げ剛性が高くなり、せん断補強筋7を横切るせん断ひび割れ(破線L3)の伸展を抑止できる。実際には、地震時にせん断力が正負繰り返し作用するため、比較的初期段階で曲げひび割れ(破線L2)が水平断面全体に貫通して拡がり、その後生じるせん断ひび割れ(破線L3)の伸展は、一般的な配筋(細径鉄筋のフープ)に比べて抑えることができる。     On the other hand, the larger the shear reinforcement bar 7 is, the higher the bending rigidity becomes, and the extension of shear cracks (broken line L3) across the shear reinforcement bar 7 can be suppressed. Actually, since the shearing force repeatedly acts positively and negatively during an earthquake, the bending crack (broken line L2) penetrates through the entire horizontal section in a relatively early stage, and the extension of the resulting shear crack (broken line L3) is generally common. It can be suppressed compared to a large reinforcing bar (a hoop of a small diameter reinforcing bar).

鉄筋によるコンクリートの断面欠損率に関して、日本建築学会編「鉄筋コンクリート造のひび割れ対策指針・同解説」において、ひび割れ誘発目地のひび割れ集中率に関する検討によれば、図6に示す結果となっており、コンクリート断面に対して20%の欠損率でひび割れが60%以上の集中率と、22%の欠損率で80%の集中率となっている。この指針では、コンクリートの乾燥収縮によるひび割れを誘発目地に集中させることを目的としているが、ひび割れ発生の外的要因が乾燥収縮か、作用せん断力かの違いであり、この考え方は本実施形態にも整合すると考えられる。     Regarding the cross-sectional defect rate of concrete due to reinforcing bars, according to the study on the crack concentration ratio of crack-induced joints in the “Architectural Guidelines for Cracks in Reinforced Concrete Structures” edited by the Architectural Institute of Japan, the results shown in FIG. The defect rate is 20% for the cross section and the crack rate is 60% or more, and the defect rate is 22% and the concentration rate is 80%. This guideline aims at concentrating cracks due to drying shrinkage of concrete at the induced joints, but the external factor of cracking is the difference between drying shrinkage and acting shear force. Are also considered to be consistent.

したがって、以上のような効果を達成するためには、外周側のせん断補強筋6’と内周側のせん断補強筋7の径の総和が部材幅に対して20%以上が望ましい。例えば、本実施形態でいえば、柱幅250mmに対して、せん断補強筋6’:2本-D13+せん断補強筋7:1本-D25で、欠損率20.4%とすることができる。せん断補強筋6’と、せん断補強筋7との配設位置は高さ方向(Z方向)で完全に一致していなくても近接していれば同様の効果が期待できる。     Therefore, in order to achieve the above effects, the total sum of the diameters of the outer peripheral shear reinforcing bar 6 'and the inner peripheral shear reinforcing bar 7 is preferably 20% or more with respect to the member width. For example, in this embodiment, with respect to a column width of 250 mm, the shear reinforcement bar 6 ': 2 pieces-D13 + shear reinforcement bar 7: 1 piece-D25, the defect rate can be 20.4%. Even if the positions where the shear reinforcement bars 6 'and the shear reinforcement bars 7 are not completely coincided with each other in the height direction (Z direction), the same effect can be expected.

なお、せん断補強筋6’と、せん断補強筋7とがZ方向に離れていても、曲げひび割れを誘発する方法として、例えば、せん断補強筋7として部材幅に対して10%以上の径の太径鉄筋を2本使用することや、あるいは、部材幅に対して20%以上の径の太径鉄筋を1本使用することが挙げられる。これにより、せん断補強筋7のみで欠損率を20%以上にでき、曲げひび割れの集中化を効果的に促進し、せん断ひび割れの伸展をせん断補強筋7の曲げ剛性によって抑えることができる。     As a method for inducing bending cracking even if the shear reinforcement 6 'and the shear reinforcement 7 are separated in the Z direction, for example, the shear reinforcement 7 has a diameter of 10% or more with respect to the member width. For example, two diameter reinforcing bars may be used, or one large diameter reinforcing bar having a diameter of 20% or more of the member width may be used. As a result, the defect rate can be increased to 20% or more with only the shear reinforcement bars 7, the concentration of bending cracks can be effectively promoted, and the extension of the shear cracks can be suppressed by the bending rigidity of the shear reinforcement bars 7.

さらに、せん断補強筋7によるコンクリート断面欠損率が20%以下でも、せん断補強筋7の径が、併用するせん断補強筋6’の2倍以上かつD19以上であれば、通常配筋(細径補強筋のフープのみ)に比べてせん断補強筋7の配設位置において曲げひび割れが先行して生じやすくなる。いずれにしろ、正負繰り返しの地震荷重によって断面を貫通する複数の曲げひび割れが発生した状態では、それらを横切るせん断ひび割れが生じづらくなるというRC部材の力学原理を応用している点が本実施形態の特徴の一つである。   Furthermore, even if the concrete cross-section defect rate due to the shear reinforcement 7 is 20% or less, if the diameter of the shear reinforcement 7 is at least twice that of the shear reinforcement 6 'used in combination and D19 or more, normal reinforcement (thinning reinforcement) Bending cracks are more likely to occur in advance at the position where the shear reinforcing bar 7 is disposed than in the case of only the muscle hoop. In any case, in this embodiment, in the state where multiple bending cracks penetrating the cross section are generated due to repeated positive and negative seismic loads, it is difficult to generate shear cracks crossing them. One of the features.

<第3実施形態>
図3(A)は本発明の別実施形態に係る補強構造を適用したRC部材である、扁平柱(壁柱)1Bの水平断面図である。扁平柱1Bは、上記第1実施形態の扁平柱1の変形例であり、同様の構成については同じ符号を付して説明を省略し、異なる点について以下に説明する。
<Third Embodiment>
FIG. 3A is a horizontal sectional view of a flat column (wall column) 1B, which is an RC member to which a reinforcing structure according to another embodiment of the present invention is applied. The flat column 1B is a modification of the flat column 1 of the first embodiment. The same reference numerals are assigned to the same components, the description thereof is omitted, and different points will be described below.

本実施形態では、扁平柱1Bを高配筋・高耐力とするために、主筋2を上記第1実施形態より増やし、それに伴いせん断補強筋7も増やしている。     In this embodiment, in order to make the flat column 1B have high reinforcement and high proof strength, the main reinforcement 2 is increased from that in the first embodiment, and the shear reinforcement reinforcement 7 is also increased accordingly.

上記第1および第2実施形態では、かぶり厚を大きくする目的で、拘束筋4に主筋2が接しないように配置した場合について説明した。しかし、より一般的な扁平柱における主筋は、図3(A)の例のように、主筋2が拘束筋4に接するように配筋されることが多い。そのような場合、図7(A)で示したように、主筋に沿ったひび割れを生じやすくなるが、せん断補強筋7を断面に対して複数列(図3(A)の例では2列)にすることで、曲げ補強筋に沿ったひび割れの防止と、高耐力で変形性能の優れた高靱性の扁平柱とすることができる。     In the first and second embodiments described above, the case where the main bar 2 is arranged so as not to contact the restraint bar 4 has been described for the purpose of increasing the cover thickness. However, the main bars in a more general flat column are often arranged so that the main bars 2 are in contact with the restraint bars 4 as in the example of FIG. In such a case, as shown in FIG. 7A, cracks along the main bars are likely to occur, but the shear reinforcing bars 7 are arranged in a plurality of rows with respect to the cross section (two rows in the example of FIG. 3A). By doing so, it is possible to provide a flat column with high toughness that prevents cracks along the bending reinforcement, and has high yield strength and excellent deformation performance.

図3(B)は、本発明の別実施形態に係る補強構造を適用したRC部材である、扁平柱(壁柱)1Cの水平断面図であり、上述した扁平柱1Bと同様に、主筋2が拘束筋4に接する配筋としている。扁平柱1Cでは、より施工を合理化する目的で、せん断補強筋6の代わりにメッシュ筋8を扁平柱1Cの両側面から設置した事例である。メッシュ筋8は、上記第2実施形態におけるせん断補強筋6’に相当する鉄筋と、上述した補強筋3に相当する鉄筋とを網目状に交差させたものに相当する。このようなメッシュ筋8は上記第1実施形態や上記第2実施形態においても採用可能である。     FIG. 3B is a horizontal cross-sectional view of a flat column (wall column) 1C, which is an RC member to which a reinforcing structure according to another embodiment of the present invention is applied. As with the flat column 1B described above, the main reinforcement 2 Are arranged in contact with the restraint muscle 4. The flat column 1C is an example in which mesh bars 8 are installed from both sides of the flat column 1C instead of the shear reinforcement bars 6 for the purpose of rationalizing the construction. The mesh reinforcement 8 corresponds to a mesh-like intersection of a reinforcing bar corresponding to the shear reinforcing bar 6 'in the second embodiment and a reinforcing bar corresponding to the reinforcing bar 3 described above. Such mesh streaks 8 can also be employed in the first embodiment and the second embodiment.

なお、断面両側の応力条件が厳しい部位で、拘束筋4とせん断補強筋7の協働効果が期待できるため、せん断補強筋7の補強量が多い場合には、断面両側の拘束域以外の中間部分では、メッシュ筋8がなくてもせん断補強筋7のみで十分なせん断補強効果が期待できる。     In addition, since the cooperative effect of the restraining bar 4 and the shear reinforcing bar 7 can be expected in a part where the stress condition on both sides of the cross section is severe, if the amount of reinforcement of the shear reinforcing bar 7 is large, the intermediate part other than the restraining area on both sides of the cross section In the portion, a sufficient shear reinforcement effect can be expected with only the shear reinforcement 7 even without the mesh reinforcement 8.

<第4実施形態>
本実施形態では、RC梁の開口部の補強に本発明の補強構造を適用したものである。図4(A)は本発明の一実施形態に係る補強構造を適用した梁11の水平断面図、(B)は垂直断面図、(C)は図4(B)の線II−IIに沿う断面図である。
<Fourth embodiment>
In this embodiment, the reinforcing structure of the present invention is applied to the reinforcement of the opening of the RC beam. 4A is a horizontal sectional view of the beam 11 to which the reinforcing structure according to the embodiment of the present invention is applied, FIG. 4B is a vertical sectional view, and FIG. 4C is along a line II-II in FIG. It is sectional drawing.

一般的な開口部補強では、開口部上下の上弦材と下弦材にせん断補強(小径のスターラップ)に加えて、開口周りに、斜め補強筋(X型等)や既製品の開口補強金物等で補強される。本実施形態ではこのような補強は採用せず、開口部上下の上弦材と下弦材の補強と、せん断応力が厳しい開口際(開口左右)の補強とを行っている。     In general opening reinforcement, in addition to shear reinforcement (small diameter stirrup) on the upper and lower chords above and below the opening, diagonal reinforcement bars (such as X-type) and ready-made opening reinforcement hardware around the opening Reinforced with. In the present embodiment, such reinforcement is not employed, and the upper chord material and the lower chord material at the top and bottom of the opening are reinforced, and the reinforcement at the time of opening where the shear stress is severe (opening left and right) is performed.

梁11は長方形断面のRC部材であり、その軸方向がX方向、梁せい方向がZ方向、梁幅方向がY方向となっている。軸方向を左右方向と呼び、梁せい方向を上下方向と呼ぶ場合がある。梁11は、その軸方向中央部に水平方向に開口した貫通孔である開口部11aを有している。また、梁11は主筋12a及び12b(総称するときは主筋12という)、せん断補強筋16、せん断補強筋17、開口補強筋18及び拘束筋19を備える。せん断補強筋16、せん断補強筋17及び開口補強筋18は本発明の一実施形態に係る補強構造を構成している。     The beam 11 is an RC member having a rectangular cross section, and its axial direction is the X direction, the beam direction is the Z direction, and the beam width direction is the Y direction. The axial direction may be referred to as the left-right direction, and the beam direction may be referred to as the up-down direction. The beam 11 has an opening 11a, which is a through hole that opens in the horizontal direction at the center in the axial direction. The beam 11 includes main bars 12a and 12b (referred to collectively as main bars 12), a shear reinforcing bar 16, a shear reinforcing bar 17, an opening reinforcing bar 18, and a restraining bar 19. The shear reinforcing bar 16, the shear reinforcing bar 17, and the opening reinforcing bar 18 constitute a reinforcing structure according to an embodiment of the present invention.

主筋12は、配置上、上側の主筋12aと、下側の主筋12bとに大別される。主筋12はX方向に延設されており、主筋12a及び主筋12bのいずれも、Y方向を列方向として1列4本の構成であり、総計で8本とされている。上側の主筋2aと、下側の主筋2bとは、互いに対向する主筋の列を構成している。     The main muscle 12 is roughly classified into an upper main muscle 12a and a lower main muscle 12b. The main muscles 12 extend in the X direction, and each of the main muscles 12a and 12b has a configuration of four in one row with the Y direction as the row direction, and the total number is eight. The upper main bar 2a and the lower main bar 2b constitute a row of main bars facing each other.

せん断補強筋16は、主筋12の外周側に配置され、本実施形態の場合、主筋12を囲むように環状を有して配置されたスターラップを構成している。せん断補強筋16としては、例えば、D10〜D16の細径鉄筋を採用できる。     The shear reinforcement bars 16 are arranged on the outer peripheral side of the main bars 12, and in the case of the present embodiment, they constitute a stirrup arranged so as to surround the main bars 12. As the shear reinforcement 16, for example, D10 to D16 small-diameter reinforcing bars can be employed.

せん断補強筋17は、主筋12の内周側において、互いに対向する主筋12aの列と主筋12bの列とを横断するようにZ方向に直線的に延設されている。せん断補強筋17は、せん断補強筋16よりも太径とした棒状鉄筋である。本実施形態の場合、せん断補強筋17は、開口部11aの左右側部にそれぞれ上下方向に配置され、片側で2×2=4本で、両側で総計8本としている。しかし、せん断補強筋17の数は適宜選択できる。     The shear reinforcement bars 17 are linearly extended in the Z direction so as to cross the rows of the main bars 12a and the main bars 12b facing each other on the inner peripheral side of the main bars 12. The shear reinforcing bar 17 is a bar-shaped reinforcing bar having a diameter larger than that of the shear reinforcing bar 16. In the case of this embodiment, the shear reinforcement 17 is arrange | positioned at the up-down direction at the right-and-left side part of the opening part 11a, respectively, It is set to 2x2 = 4 on one side and a total of eight on both sides. However, the number of shear reinforcement bars 17 can be selected as appropriate.

せん断補強筋17の両端部にはプレート型定着部17a、17aが設けられている。プレート型定着部17aは、上記第1実施形態と同様、せん断補強筋17の径方向に突出してせん断補強筋7端部の定着性を向上できる構成であればどのような構成でもよい。プレート型定着部17aは主筋12の外周側に配置されている。本実施形態の場合、プレート型定着部17aを主筋12に引っ掛けるように配置している。この構成はせん断補強筋17に引っ張り力が作用した場合にせん断補強筋17の定着性を向上させる。     Plate-type fixing portions 17 a and 17 a are provided at both ends of the shear reinforcement 17. As in the first embodiment, the plate-type fixing unit 17a may have any configuration as long as the plate-type fixing unit 17a can protrude in the radial direction of the shear reinforcing bar 17 and improve the fixing property of the end of the shear reinforcing bar 7. The plate-type fixing unit 17 a is disposed on the outer peripheral side of the main bar 12. In the case of the present embodiment, the plate-type fixing unit 17a is arranged to be hooked on the main muscle 12. This configuration improves the fixing property of the shear reinforcement 17 when a tensile force acts on the shear reinforcement 17.

本実施形態では、梁11の上側および下側において、主筋2がそれぞれ1段配筋のため、開口部11a上下の開口に近接した部位に開口補強筋18を施している。なお、主筋2が多段配筋の場合等の構成の場合、開口補強筋18を省略することができる。     In this embodiment, the main reinforcing bars 2 are arranged in a single step on the upper side and the lower side of the beam 11, respectively, so that the opening reinforcing bars 18 are provided at portions close to the upper and lower openings of the opening 11 a. In addition, in the case of a configuration in which the main reinforcing bars 2 are multistage reinforcing bars, the opening reinforcing bars 18 can be omitted.

開口補強筋18は、開口部11aの上部及び下部にそれぞれ配置され、左右方向に直線的に延設された直線棒状の鉄筋である。開口補強筋18の両端部にはプレート型定着部18aが設けられている。プレート型定着部18aは、上記第1実施形態のプレート型定着部7aと同様、開口補強筋18の径方向に突出して開口補強筋18端部の定着性を向上できる構成であればどのような構成でもよい。プレート型定着部18aは必須ではないが、本実施形態では破壊を誘発するひび割れを効率的かつ強制的に拘束することを目的として、あえて設けている。拘束筋19は主筋2と開口補強筋18とを囲むように配筋されている。     The opening reinforcing bars 18 are linear bar-like reinforcing bars that are respectively arranged at the upper and lower parts of the opening 11a and extend linearly in the left-right direction. Plate type fixing portions 18 a are provided at both ends of the opening reinforcing bars 18. The plate-type fixing unit 18a may be any configuration as long as the plate-type fixing unit 18a protrudes in the radial direction of the opening reinforcing bar 18 and can improve the fixing property of the end of the opening reinforcing bar 18 similarly to the plate-type fixing unit 7a of the first embodiment. It may be configured. The plate-type fixing unit 18a is not essential, but in the present embodiment, it is purposely provided for the purpose of efficiently and forcibly constraining cracks that induce destruction. The restraint bars 19 are arranged so as to surround the main bars 2 and the opening reinforcing bars 18.

係る構成からなる梁11では、太径のせん断補強筋17が圧壊を誘発する主筋12や開口補強筋18近傍の位置のひび割れ(破線L4)の拡大を直接拘束する配筋となっており、ひび割れの拡大・伸展を十分抑止できる。また、開口補強筋18も破壊を誘発するひび割れを拘束する。せん断補強筋17は、また、主筋12の付着条件が厳しい場合に生じる主筋12に沿った付着割裂ひび割れの抑止にも効果を発揮する。     In the beam 11 having such a configuration, the large-diameter shear reinforcing bar 17 is a reinforcing bar that directly restrains the expansion of cracks (broken line L4) near the main reinforcing bar 12 and the opening reinforcing bar 18 that induce crushing. Can be sufficiently deterred. Further, the opening reinforcing bar 18 also restrains a crack that induces a fracture. The shear reinforcing bar 17 is also effective in suppressing adhesion splitting cracks along the main bar 12 that occurs when the main bar 12 has severe conditions.

せん断補強筋17は直線の棒状鉄筋であり、曲げ加工を要しないので太径としても施工性を悪化させない。更に、その両端部にプレート型定着部17aを設けたので、定着性を向上できるだけでなく、かぶりがプレート型定着部17aの厚みには影響されるものの、せん断補強筋17の径に影響されず、より太径の鉄筋を利用した場合であっても、かぶりを確保しやすくなっている。     The shear reinforcing bar 17 is a straight bar-like reinforcing bar and does not require bending work, so that the workability is not deteriorated even if the diameter is large. Further, since the plate-type fixing portions 17a are provided at both ends thereof, not only the fixing property can be improved, but the fogging is influenced by the thickness of the plate-type fixing portion 17a, but is not affected by the diameter of the shear reinforcing bar 17. Even when a thicker reinforcing bar is used, it is easy to ensure the cover.

こうして本実施形態の補強構造でも、上記第1実施形態の補強構造と同様、かぶりを確保するとともに施工性を悪化させることなく、応力条件が厳しい部位(ここでは開口部11a近傍)へ、より太径の鉄筋を利用してそのせん断補強を行うことができる。また、配筋方法が簡易かつ合理的なため、終局耐力等の設計法が明快かつ簡便なものとなる。     In this way, in the reinforcing structure of the present embodiment as well, as in the reinforcing structure of the first embodiment, the cover is secured and a thicker part (here in the vicinity of the opening 11a) is stressed without deteriorating the workability. The shear reinforcement can be performed using a reinforcing bar having a diameter. In addition, since the bar arrangement method is simple and rational, the design method for ultimate strength and the like becomes clear and simple.

<第5実施形態>
図5は本発明の別実施形態に係る補強構造を適用したRC部材である、梁11’の垂直断面図である。梁11’は、上記第3実施形態の梁11の変形例であり、同様の構成については同じ符号を付して説明を省略し、異なる点について以下に説明する。
<Fifth Embodiment>
FIG. 5 is a vertical sectional view of a beam 11 ′ that is an RC member to which a reinforcing structure according to another embodiment of the present invention is applied. The beam 11 ′ is a modification of the beam 11 of the third embodiment. The same components are denoted by the same reference numerals, description thereof is omitted, and different points will be described below.

本実施形態の場合、主筋2は上下で2段構成とされており、上記第3実施形態の開口補強筋18は省略されて拘束筋19’は上側の主筋2aと、下側の主筋2bとをそれぞれ囲む構成である。     In the case of the present embodiment, the main reinforcement 2 has a two-stage configuration in the upper and lower directions, the opening reinforcement 18 in the third embodiment is omitted, and the restraining reinforcement 19 'includes an upper main reinforcement 2a and a lower main reinforcement 2b. Are each enclosed.

梁11’は開口部11aが複数形成されている。同図の例では、開口部11aの間隔を開口径の2倍としているが、通常は開口径の3倍以上とされている(日本建築学会編:鉄筋コンクリート造配筋指針・同解説)。     The beam 11 'has a plurality of openings 11a. In the example shown in the figure, the interval between the openings 11a is set to be twice the opening diameter, but is usually set to three or more times the opening diameter (edited by the Architectural Institute of Japan: Reinforced concrete bar arrangement guide).

このような複数の開口部11aを有するRC梁では、同図に示す開口部11a間の束材と開口部11a上下の弦材の耐力の低い方で梁11’の終局せん断耐力が決まる。図5において、破線L5は上弦材の破壊線を、破線L6は下弦材の破壊線を、破線L7は束材の破壊線を、それぞれ示している。破壊線上の補強量が多いとコンクリートのせん断圧縮破壊が、補強量が少なくなると破壊線上のせん断ひび割れの拡大が最終破壊形式となる。     In such an RC beam having a plurality of openings 11a, the ultimate shear strength of the beam 11 'is determined by the lower one of the strength of the bundle material between the openings 11a shown in FIG. In FIG. 5, a broken line L5 indicates a breaking line for the upper chord material, a broken line L6 indicates a breaking line for the lower chord material, and a broken line L7 indicates a breaking line for the bundle material. When the amount of reinforcement on the fracture line is large, the shear compression fracture of concrete becomes the final fracture type, and when the amount of reinforcement decreases, the expansion of shear cracks on the fracture line becomes the final fracture type.

せん断補強筋17は、各開口部11aの左右両側に配置されている。せん断補強筋17は、開口部11a上下の弦材および束材の破壊防止に有効に働く。なお、束材の補強には、通常、開口部11aの側方を斜めに通過する斜め補強筋が有効であるが、開口部11aの間隔を通常の間隔(開口径の3倍以上)とした場合、束材の破壊線L7が図示の例の傾き(約30°)よりも水平に近くなる。補強筋はひび割れに直交する方が効果的とされる一般論からすると、必ずしも斜め補強筋と効果において大きな差はなく、せん断補強筋17によって、破壊線上での鉄筋の曲げ剛性も高く、せん断ひび割れの伸展・拡大を抑止できるので、施工性を考えると従来工法(斜め補強等)より合理的である。     The shear reinforcement 17 is arrange | positioned at the both right and left sides of each opening part 11a. The shear reinforcement 17 works effectively for preventing the breakage of the string material and the bundle material above and below the opening 11a. In addition, for reinforcement of the bundle material, an oblique reinforcing bar that obliquely passes through the side of the opening portion 11a is effective, but the interval between the opening portions 11a is set to a normal interval (more than three times the opening diameter). In this case, the fracture line L7 of the bundle is closer to the horizontal than the inclination (about 30 °) in the illustrated example. From the general theory that it is more effective to reinforce the reinforcing bars perpendicular to the cracks, the effect is not necessarily different from that of the oblique reinforcing bars, and the shear reinforcing bars 17 have high bending rigidity of the reinforcing bars on the fracture line. It is more rational than conventional methods (diagonal reinforcement, etc.) in terms of workability.

なお、開口部11aの位置が梁端部に近くなるほど、部材の曲げ応力によりせん断補強筋17に沿って曲げひび割れが生じやすく、有害なせん断ひび割れの伸展・拡大の抑止効果が更に増大する。     As the position of the opening 11a is closer to the beam end, bending cracks are more likely to occur along the shear reinforcement bars 17 due to the bending stress of the member, and the effect of suppressing the extension / expansion of harmful shear cracks is further increased.

<他の実施形態>
上記第1〜第5実施形態では、RC造の柱および梁(開口補強)を対象として示したが、本発明の適用対象はこれらに限られるものでなく、柱型のない耐震壁や壁式構造における耐力壁のせん断補強や開口補強等、各種のRC部材に適用可能であり、特に、長方形断面を有するRC部材の長辺方向のせん断補強に有益である。また、プレストレストコンクリート造部材についても適用可能である。
<Other embodiments>
In the first to fifth embodiments, RC columns and beams (opening reinforcement) are shown as targets. However, the application target of the present invention is not limited to these, and a seismic wall or wall type without a column shape is used. The present invention can be applied to various RC members such as shear reinforcement of bearing walls and opening reinforcement in the structure, and is particularly useful for shear reinforcement in the long side direction of RC members having a rectangular cross section. It can also be applied to prestressed concrete members.

本発明によれば、鉄筋コンクリート壁柱の補強構造であって、前記鉄筋コンクリート部材の両隅部には、複数の主筋を囲むように拘束筋がそれぞれ配設されており、前記鉄筋コンクリート部材の主筋の外周側に配設された第1のせん断補強筋と、前記主筋の内周側において、互いに対向する前記主筋の列を横断するように直線的に延設された第2のせん断補強筋と、を備え、前記第2のせん断補強筋は、前記第1のせん断補強筋よりも太径であることを特徴とする補強構造が提供される。
また、本発明によれば、開口部を有する鉄筋コンクリート梁部材の補強構造であって、前記鉄筋コンクリート梁部材には、前記開口部の上側の主筋と下側の主筋とが配設され、前記上側の主筋および前記下側の主筋の外周側には第1のせん断補強筋が環状に配設されており、前記開口部の左右側部にそれぞれ上下方向に配置された第2のせん断補強筋と、前記開口部の上部及び下部にそれぞれ配置され、左右方向に直線的に延設された開口補強筋と、を備え、前記開口部の上部側では、前記上側の主筋同士、または前記上側の主筋と前記開口補強筋を囲むように配設されるとともに、前記開口部の下部側では、前記下側の主筋同士、または前記下側の主筋と前記開口補強筋を囲むように其々拘束筋が配設されることを特徴とする鉄筋コンクリート梁部材の補強構造が提供される。

According to the present invention, there is provided a reinforcing structure for a reinforced concrete wall column , and constraining bars are respectively disposed at both corners of the reinforced concrete member so as to surround a plurality of main bars, and the outer periphery of the main bar of the reinforced concrete member A first shear reinforcing bar disposed on the side, and a second shear reinforcing bar extending linearly so as to cross the row of the main bars facing each other on the inner peripheral side of the main bar. wherein the second shear reinforcement, the reinforcing structure characterized by a large diameter der Turkey than the first shear reinforcement is provided.
Further, according to the present invention, there is provided a reinforcing structure for a reinforced concrete beam member having an opening, and the reinforced concrete beam member is provided with an upper main bar and a lower main bar of the opening, and the upper the outer periphery of the main reinforcement and the lower main reinforcement are first shear reinforcement is arranged annularly, a second shear reinforcement arranged vertically on the left and right sides of the front Symbol opening are arranged respectively on the top and bottom of the opening, with an opening reinforcement which is linearly extended, the right and left direction, the upper side of the opening, the main reinforcement together of the upper or the upper main reinforcement, Are arranged so as to surround the opening reinforcing bars, and on the lower side of the opening, there are restraining bars so as to surround the lower main bars or the lower main bars and the opening reinforcing bars, respectively. rebar characterized in that it is arranged concrete Reinforcing structure DOO beam member.

Claims (4)

鉄筋コンクリート部材の補強構造であって、
前記鉄筋コンクリート部材の主筋の外周側に配設された第1のせん断補強筋と、
前記主筋の内周側において、互いに対向する前記主筋の列を横断するように直線的に延設された第2のせん断補強筋と、を備え、
前記第2のせん断補強筋は、
前記第1のせん断補強筋よりも太径であり、かつ、
その両端部に、前記主筋の外周側に位置するプレート型定着部を備えることを特徴とする補強構造。
A reinforcing structure for a reinforced concrete member,
A first shear reinforcing bar disposed on the outer peripheral side of the main reinforcing bar of the reinforced concrete member;
A second shear reinforcement bar extending linearly so as to cross the row of the main bars facing each other on the inner peripheral side of the main bar,
The second shear reinforcement is
Larger diameter than the first shear reinforcement, and
A reinforcing structure comprising plate-type fixing portions positioned on the outer peripheral side of the main bar at both ends thereof.
前記第1のせん断補強筋と前記第2のせん断補強筋とが、前記主筋の列方向と平行な方向で互いに重なるように配置されていることを特徴とする請求項1に記載の補強構造。     2. The reinforcing structure according to claim 1, wherein the first shear reinforcing bar and the second shear reinforcing bar are arranged so as to overlap each other in a direction parallel to the row direction of the main bars. 前記鉄筋コンクリート部材が、水平方向に開口した開口部を有する梁部材であり、
前記第2のせん断補強筋が、前記開口部の左右側部にそれぞれ上下方向に配置され、
前記補強構造は、更に、
前記開口部の上部及び下部にそれぞれ配置され、左右方向に直線的に延設された開口補強筋を備え、
前記開口補強筋は、
前記第1のせん断補強筋よりも太径の鉄筋であり、かつ、
その両端部に、プレート型定着部を備えることを特徴とする請求項1に記載の補強構造。
The reinforced concrete member is a beam member having an opening portion opened in a horizontal direction,
The second shear reinforcement bars are arranged vertically on the left and right sides of the opening,
The reinforcing structure further includes:
It is arranged at the upper part and the lower part of the opening part, respectively, and comprises an opening reinforcing bar extending linearly in the left-right direction,
The opening reinforcing bar is
A reinforcing bar having a diameter larger than that of the first shear reinforcing bar, and
The reinforcing structure according to claim 1, further comprising a plate-type fixing unit at both ends thereof.
前記第2のせん断補強筋は、
前記第1のせん断補強筋よりも2倍以上太径であることを特徴とする請求項1に記載の補強構造。
The second shear reinforcement is
The reinforcing structure according to claim 1, wherein the reinforcing structure has a diameter two or more times that of the first shear reinforcing bar.
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JPS60133171A (en) * 1983-12-21 1985-07-16 Takenaka Komuten Co Reinforced concrete earthquake-proof wall
JPH08260565A (en) * 1995-03-20 1996-10-08 Kawatetsu Techno Wire Kk Reinforced concrete wall column
JP2012077606A (en) * 2011-11-28 2012-04-19 Taisei Corp Concrete structure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60133171A (en) * 1983-12-21 1985-07-16 Takenaka Komuten Co Reinforced concrete earthquake-proof wall
JPH08260565A (en) * 1995-03-20 1996-10-08 Kawatetsu Techno Wire Kk Reinforced concrete wall column
JP2012077606A (en) * 2011-11-28 2012-04-19 Taisei Corp Concrete structure

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