JP6666203B2 - A method for estimating the allowable pull-out strength of anchor members embedded in short fiber reinforced cementitious materials - Google Patents

A method for estimating the allowable pull-out strength of anchor members embedded in short fiber reinforced cementitious materials Download PDF

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JP6666203B2
JP6666203B2 JP2016110090A JP2016110090A JP6666203B2 JP 6666203 B2 JP6666203 B2 JP 6666203B2 JP 2016110090 A JP2016110090 A JP 2016110090A JP 2016110090 A JP2016110090 A JP 2016110090A JP 6666203 B2 JP6666203 B2 JP 6666203B2
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貴彦 網野
貴彦 網野
亮一 田中
亮一 田中
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本発明は、固化した短繊維補強セメント系材料に埋設されているアンカー部材を引き抜く際の許容引抜き耐力を精度よく推定できる方法に関するものである。   The present invention relates to a method for accurately estimating an allowable pull-out strength when pulling out an anchor member embedded in a solidified short fiber-reinforced cementitious material.

建築構造部材をコンクリート等のセメント系材料に固定する固定具として、セメント材料に埋込んで使用される大径頭部を有するアンカー部材（頭付きアンカーボルト）が知られている。従来、通常のコンクリートに埋設されているアンカー部材を引き抜く際の許容引抜き耐力は、日本建築学会「各種合成構造設計指針・同解説（２０１０）第４編各種アンカーボルト設計指針」で提示されている以下の（Ｘ）式および（Ｙ）式（以下、建築学会式という）に基づいて算出されている（特許文献１参照）。
Ｐｋ＝Φ・ｕσｔ・Ａｋ・・・（Ｘ）
Ａｋ＝π・Ｌ（Ｌ＋Ｄ）・・・（Ｙ）
ここで、Ｐｋは許容引抜き耐力、Φは低減係数、ｕσｔは材料の引張強度、Ａｋは下記（Ｙ）より算出されるコーン状破壊面の有効水平投影面積、Ｌはアンカー部材の埋込み長、Ｄは大径頭部の頭部径である。 As an anchor for fixing a building structural member to a cement-based material such as concrete, an anchor member (anchor bolt with a head) having a large diameter head used by being embedded in a cement material is known. Conventionally, the permissible pull-out strength at the time of pulling out an anchor member buried in ordinary concrete is presented in the Architectural Institute of Japan's "Guidelines for Designing Various Synthetic Structures / Commentary (2010), Fourth Edition, Guidelines for Designing Various Anchor Bolts". It is calculated based on the following formulas (X) and (Y) (hereinafter, referred to as Architectural Institute formula) (see Patent Document 1).
P k = Φ · u σ t · A k (X)
A k = π · L (L + D) (Y)
Here, P k is the allowable pull strength, [Phi is the reduction coefficient, u sigma t is the tensile strength of the material, A k is the effective horizontal projected area of the conical fracture surface which is calculated by the following (Y), L is the anchor member The embedding length, D, is the head diameter of the large diameter head.

ところで、通常のコンクリートに比べて引張力に対する変形性能に優れ、引張強度および靭性に優れた建材として超高強度ひずみ硬化型セメント系材料（以下、ＵＨＰ−ＳＨＣＣという）等の短繊維補強セメント系材料が知られている（特許文献２参照）。ＵＨＰ−ＳＨＣＣにアンカー部材を埋設して引抜き試験を行ったところ、測定された引抜き耐力と建築学会式に基づいて算出した計算値とは結果が大きく異なることが判明した。そのため、短繊維補強セメント系材料のように、通常のコンクリートと引張強度や靱性能が大きく異なる材料に埋設されているアンカー部材を引き抜く際の引抜き耐力を精度よく推定するには改善の余地がある。   By the way, short fiber reinforced cementitious materials such as ultra-high strength strain hardening type cementitious materials (hereinafter referred to as UHP-SHCC) as building materials which are superior in deformation performance to tensile force and superior in tensile strength and toughness as compared with ordinary concrete. Is known (see Patent Document 2). When a pull-out test was conducted by embedding the anchor member in UHP-SHCC, it was found that the measured pull-out strength was significantly different from the calculated value calculated based on the Architectural Institute of Japan formula. Therefore, there is room for improvement in accurately estimating the pull-out strength when pulling out an anchor member embedded in a material such as a short fiber reinforced cementitious material that has significantly different tensile strength and toughness from ordinary concrete. .

特開２０１４−１６７２０２号公報JP 2014-167202 A 特開２０１１−１８４８５９号公報JP 2011-184859 A

本発明の目的は、固化した短繊維補強セメント系材料に埋設されているアンカー部材を引き抜く際の許容引抜き耐力を精度よく推定できる方法を提供することにある。   An object of the present invention is to provide a method capable of accurately estimating an allowable pull-out strength when pulling out an anchor member embedded in a solidified short fiber-reinforced cementitious material.

上記目的を達成するための本発明は、固化した短繊維補強セメント系材料に埋設されているアンカー部材を引き抜く際の許容引抜き耐力Ｐｅを下記（１）式を用いて推定する方法であって、
Ｐｅ＝Φ・ｕσｔ・Ａｅ・・・（１）
ここで、Φは低減係数、ｕσｔは前記材料の引張強度、Ａｅは下記（２）式より算出される有効水平投影面積であり、
Ａｅ＝π（Ｌ／ｔａｎθｅ）｛（Ｌ／ｔａｎθｅ）＋Ｄ｝・・・（２）
ここで、Ｌは前記アンカー部材の埋込み長、Ｄは前記大径頭部の頭部径、θｅは推定破壊角度であり、
固化した前記材料に埋設されている前記アンカー部材の引抜き試験により取得した実測最大引張荷重を、固化した前記材料の引張試験により取得した実測引張強度により除して算出された値（以下、推定水平投影面積という）を、前記有効水平投影面積Ａｅとして前記（２）式に代入して前記引抜き試験の条件に基づいて推定破壊角度θｅを予め把握しておき、
前記許容引抜き耐力Ｐｅを推定する際に、予め把握した前記推定破壊角度θｅを代入した前記（１）式を用いることを特徴とする。 The present invention for achieving the above object, the allowable pull strength P e when removing the anchoring member that is embedded in the short fiber reinforced cement-based material was solidified by a method of estimating using the following equation (1) ,
P e = Φ · u σ t · A e (1)
Here, Φ is the reduction coefficient, u σ t is the tensile strength of the material, A e is the effective horizontal projected area calculated from the following equation (2),
A e = π (L / tan θ e ) {(L / tan θ e ) + D} (2)
Here, L is embedded length of the anchor member, D is the head diameter of the large-diameter head, theta e is an estimated fracture angle,
A value calculated by dividing an actually measured maximum tensile load obtained by a pull-out test of the anchor member embedded in the solidified material by an actually measured tensile strength obtained by a tensile test of the solidified material (hereinafter, estimated horizontal load) (Referred to as a projected area) as the effective horizontal projected area A e in the equation (2), and an estimated breaking angle θ e is grasped in advance based on the conditions of the pull-out test.
When estimating the allowable pull-out strength P e , the formula (1) in which the estimated breaking angle θ e grasped in advance is substituted is used.

本発明によれば、固化した短繊維補強セメント系材料に埋設されているアンカー部材の引抜き試験の結果と固化した前記材料の引張試験の結果とに基づいて、その材料の推定破壊角度θｅをより正確に把握する。そして、この予め把握した推定破壊角度θｅを代入した（１）式を用いて許容引抜き耐力Ｐｅを推定することにより、材料の種類に応じた許容引抜き耐力を、従来に比して一段と精度よく推定することができる。前記材料は通常のコンクリートとは引張強度や靱性能が大きく異なる短繊維補強セメント系材料であり、例えば、ＵＨＰ‐ＳＨＣＣである。前記材料がＵＨＰ‐ＳＨＣＣである場合には、前記推定破壊角度は、例えば、３７°以上４１°以下の範囲となる。 According to the present invention, based on the results of the pull-out test of the anchor member embedded in the solidified short fiber reinforced cementitious material and the results of the tensile test of the solidified material, the estimated fracture angle θ e of the material is determined. Know more accurately. Then, by estimating the allowable pull strength P e by using the previously obtained by substituting the estimated fracture angle theta e after grasping (1), an allowable withdrawal strength in accordance with the type of material, more than the conventional precision Can be estimated well. The material is a short fiber-reinforced cementitious material that differs greatly from ordinary concrete in tensile strength and toughness, for example, UHP-SHCC. When the material is UHP-SHCC, the estimated breaking angle is, for example, in a range of 37 ° or more and 41 ° or less.

前記許容引抜き耐力Ｐｅを推定する際に、前記推定破壊角度θｅを代入した前記（２）式により算出される前記有効水平投影面積Ａｅが、材料に埋設されたアンカー部材の軸心を中心としてその大径頭部の外周側に広がる円環体の面積と仮定した場合に、この円環体の外側円の半径が、このアンカー部材の軸心からこの材料の端面までの距離よりも大きいときは、前記（１）式により算出される許容引抜き耐力Ｐｅを減ずる補正を行なうとよい。これにより、アンカー部材の実際の埋設条件に適した許容引抜き耐力を高精度で推定することができる。 When estimating the allowable pull-out strength P e , the effective horizontal projected area A e calculated by the expression (2) into which the estimated breaking angle θ e is substituted is determined by the axial center of the anchor member embedded in the material. Assuming that the area of an annular body extending to the outer peripheral side of the large diameter head as the center, the radius of the outer circle of the annular body is larger than the distance from the axis of the anchor member to the end face of the material. big case, the (1) may perform correction to reduce the allowable pull strength P e calculated by the equation. As a result, the allowable pull-out strength suitable for the actual embedding condition of the anchor member can be estimated with high accuracy.

図１（ａ）は固化した短繊維補強セメント系材料に埋設されているアンカー部材および推定破壊角度を縦断面視で例示する説明図、図１（ｂ）はアンカー部材およびコーン状破壊面の有効水平投影面積を平面視で例示する説明図である。FIG. 1A is an explanatory view exemplifying an anchor member buried in a solidified short fiber-reinforced cementitious material and an estimated breaking angle in a longitudinal sectional view, and FIG. 1B is a diagram showing the effectiveness of the anchor member and a cone-shaped breaking surface. It is explanatory drawing which illustrates a horizontal projection area in planar view. 本発明の手順を例示するフロー図である。FIG. 4 is a flowchart illustrating a procedure of the present invention. アンカー部材の引抜き試験を実施している状態を縦断面視で例示する説明図である。It is explanatory drawing which illustrates the state which is performing the pull-out test of an anchor member in longitudinal cross-sectional view. 図４（ａ）はアンカー部材を引抜いたときに材料に形成される破壊面を縦断面視で例示し、図４（ｂ）は平面視で例示する説明図である。FIG. 4A is an explanatory view illustrating a fracture surface formed in a material when the anchor member is pulled out in a longitudinal sectional view, and FIG. 図５（ａ）はへりあきが短い条件下でアンカー部材を引抜いたときに材料に形成される破壊面を縦断面視で例示し、図５（ｂ）は平面視で例示する説明図である。FIG. 5A is an explanatory diagram illustrating a fracture surface formed in a material when the anchor member is pulled out under a short edge condition in a longitudinal sectional view, and FIG. 5B is an explanatory diagram illustrating a fracture surface in a plan view. . 実測最大引張荷重と建築学会式で算出した許容引抜き耐力との関係を例示するグラフ図である。It is a graph figure which illustrates the relationship between the measured maximum tensile load and the permissible pull-out strength calculated by the Architectural Institute of Japan formula. 実測最大引張荷重と実測水平投影面積の関係を例示するグラフ図である。It is a graph which illustrates the relationship between the measured maximum tensile load and the measured horizontal projection area. 推定水平投影面積と実測水平投影面積の関係を例示するグラフ図である。FIG. 9 is a graph illustrating a relationship between an estimated horizontal projected area and an actually measured horizontal projected area. 実測最大引張荷重と本発明の推定式で求めた許容引抜き耐力の関係を例示するグラフ図である。FIG. 4 is a graph illustrating the relationship between the measured maximum tensile load and the allowable pull-out strength obtained by the estimation formula of the present invention.

以下、本発明の短繊維補強セメント系材料に埋設されたアンカー部材の許容引抜き耐力の推定方法を図に示した実施形態に基づいて説明する。   Hereinafter, a method for estimating the allowable pull-out strength of an anchor member embedded in a short fiber-reinforced cementitious material according to the present invention will be described based on an embodiment shown in the drawings.

本発明は、図１に例示するように、固化した短繊維補強セメント系材料２に埋設されている大径頭部１ａを有するアンカー部材１を引き抜く際の許容引抜き耐力Ｐｅを推定する。大径頭部１ａを有するアンカー部材１とは、いわゆる頭付きボルトやこれに類するアンカー部材である。 The present invention, as illustrated in FIG. 1, to estimate the allowable pull strength P e when removing the anchoring member 1 having a large-diameter head portion 1a is embedded in the short fiber reinforced cement-based material 2 was solidified. The anchor member 1 having the large-diameter head 1a is a so-called headed bolt or an anchor member similar thereto.

短繊維補強セメント系材料２とは、コンクリートの引張強度、曲げ強度、靱性（変形性能）を高めるために、短繊維を砂利、砂、セメント、水で構成されるコンクリートに複合させたコンクリート材である。短繊維とは、合成繊維（炭素やガラス、アラミド、ポリプロピレンなど）や鋼繊維などの連続繊維を数ｍｍ〜数ｃｍに短く切断したものである。具体的には、繊維の直径が０．０４ｍｍ程度、長さ１２ｍｍ程度、弾性係数４０．６ＧＰａ程度、引張破断強度１６９０ＭＰａ程度のポリビニルアルコール（ＰＶＡ）繊維や高強度ポリエチレン繊維を例示できる。或いは、繊維の直径が０．０１２ｍｍ程度、密度０．９７ｇ／ｃｍ２、弾性係数８８ＧＰａ程度、引張破断強度２７００ＭＰａ程度の高強度ポリエチレン繊維を例示できる。 The short fiber reinforced cementitious material 2 is a concrete material in which short fibers are combined with concrete composed of gravel, sand, cement, and water in order to increase the tensile strength, bending strength, and toughness (deformability) of the concrete. is there. The short fiber is obtained by cutting a continuous fiber such as a synthetic fiber (carbon, glass, aramid, polypropylene, etc.) or a steel fiber into a few mm to a few cm. Specifically, a polyvinyl alcohol (PVA) fiber or a high strength polyethylene fiber having a fiber diameter of about 0.04 mm, a length of about 12 mm, an elastic coefficient of about 40.6 GPa, and a tensile breaking strength of about 1690 MPa can be exemplified. Alternatively, high-strength polyethylene fibers having a fiber diameter of about 0.012 mm, a density of 0.97 g / cm 2 , an elastic coefficient of about 88 GPa, and a tensile breaking strength of about 2700 MPa can be exemplified.

このアンカー部材１を上方に引き抜くと、図中の二点鎖線で示すように材料２がコーン状に破壊されて、アンカー部材１とともに引き上げられる。本発明はこのように、アンカー部材１を材料２から引き抜いた際に、材料２にはコーン状の破壊面Ｓが形成される破壊モデルを想定している。   When the anchor member 1 is pulled upward, the material 2 is broken into a cone as shown by a two-dot chain line in the figure, and is pulled up together with the anchor member 1. The present invention thus assumes a fracture model in which a cone-shaped fracture surface S is formed in the material 2 when the anchor member 1 is pulled out of the material 2.

許容引抜き耐力Ｐｅを推定するには下記（１）式を用いる。
Ｐｅ＝Φ・ｕσｔ・Ａｅ・・・（１）
ここで、Φは低減係数、ｕσｔは材料２の引張強度、Ａｅは下記（２）式より算出される有効水平投影面積である。
Ａｅ＝π（Ｌ／ｔａｎθｅ）｛（Ｌ／ｔａｎθｅ）＋Ｄ｝・・・（２）
ここで、Ｌはアンカー部材１の埋込み長、Ｄは大径頭部１ａの頭部径、θｅは推定破壊角度である。 Allowed to estimate the pull-out strength P e uses the following equation (1).
P e = Φ · u σ t · A e (1)
Here, Φ is the reduction coefficient, u σ t is the tensile strength of the material 2, and Ae is the effective horizontal projected area calculated from the following equation (2).
A e = π (L / tan θ e ) {(L / tan θ e ) + D} (2)
Here, L is embedded length of the anchor member 1, D the head diameter of the large-diameter head portion 1a, the theta e is the estimated fracture angle.

低減係数Φはいわゆる安全係数であり、材料２に埋設されているアンカー部材１を長期的な建材として用いる場合には１／３に設定され、仮設のような短期的な建材として用いる場合には２／３に設定される。埋込み長Ｌは、大径頭部１ａの上面から材料２の上面までの長さである。   The reduction coefficient Φ is a so-called safety coefficient, and is set to 1/3 when the anchor member 1 embedded in the material 2 is used as a long-term building material, and when the anchor member 1 is used as a short-term building material such as temporary construction. Set to 2/3. The embedding length L is a length from the upper surface of the large diameter head 1 a to the upper surface of the material 2.

推定破壊角度θｅは、縦断面における材料２の上面（アンカー部材１に直交する方向）に対するコーン状の破壊面Ｓがなす角度である。したがって、有効水平投影面積Ａｅは、この破壊面Ｓを材料２の上面２ａに水平投影した面積からアンカー部材１の支圧面積（大径頭部１ａの面積）を除いた円環体Ｒ（格子模様部分）の面積となる。 Estimating fracture angle theta e is an angle conical fracture surface S with respect to the upper surface of the material 2 in longitudinal section (direction perpendicular to the anchoring member 1) is formed. Therefore, the effective horizontal projection area Ae is an annular body R (R) obtained by removing the bearing area (the area of the large-diameter head 1a) of the anchor member 1 from the area obtained by horizontally projecting the fracture surface S onto the upper surface 2a of the material 2. (Grid pattern portion).

許容引抜き耐力Ｐｅを推定する手順は図２に例示するとおりである。必要な種類（仕様）の材料２に対してアンカー部材１の引抜き試験と、材料２の引張強度試験とを行ってそれぞれの材料２について推定破壊角度θｅを予め把握する。 Procedure for estimating the allowable pull strength P e is as illustrated in FIG. And pulling test of the anchor member 1 with respect to the material 2 type (specification) required to grasp beforehand the estimated fracture angle theta e for each of the materials 2 tensile strength test and perform material 2.

アンカー部材１の引抜き試験は、図３に例示するように実施する。大径頭部１ａを下方にしてアンカー部材１を材料２に埋設し、固化した材料２の上面からアンカー部材１を突出させた状態にする。この実施形態では、大径頭部１ａは頭部径Ｄの円盤状になっている。大径頭部１ａが非円形の場合は、大径頭部１ａの面積に相当する円形の直径を頭部径Ｄにする。   The pull-out test of the anchor member 1 is performed as illustrated in FIG. The anchor member 1 is embedded in the material 2 with the large-diameter head 1a downward, and the anchor member 1 is made to protrude from the upper surface of the solidified material 2. In this embodiment, the large diameter head 1a has a disk shape with a head diameter D. When the large-diameter head 1a is non-circular, a circular diameter corresponding to the area of the large-diameter head 1a is set as the head diameter D.

このアンカー部材１の上端部をカプラ等で把持して、センターホールジャッキ４を有する引抜き試験機３などを用いてアンカー部材１を上方に引き抜く。このときの実測最大引張荷重Ｐｔを取得する。 The upper end of the anchor member 1 is gripped by a coupler or the like, and the anchor member 1 is pulled upward using a pull-out tester 3 having a center hole jack 4 or the like. Obtaining a measured maximum tensile load P t in this case.

材料２の引張強度試験では、固化した材料２の引張強度ｕσｔを取得する。引張強度ｕσｔは、例えば、土木学会コンクリートライブラリー１２７「複数微細ひび割れ型繊維補強セメント複合材料設計・施工指針（案）」で掲示されている一軸直接引張試験方法により取得できる。 In the tensile strength test of the material 2, the tensile strength u σ t of the solidified material 2 is obtained. The tensile strength u σ t can be obtained, for example, by a uniaxial direct tensile test method disclosed in the Concrete Library 127 of the Japan Society of Civil Engineers “Guidelines for Design and Execution of Plural Fine Crack Type Fiber Reinforced Cement Composite Materials”.

取得した実測最大引張荷重Ｐｔを、取得した実測引張強度ｕσｔにより除した値である推定水平投影面積Ａを算出する。即ち、推定水平投影面積Ａ＝Ｐｔ／ｕσｔとなる。次いで、算出した推定水平投影面積Ａを、有効水平投影面積Ａｅとして（２）式に代入する。また、この（２）式に引抜き試験を実施した条件（埋込み長Ｌ、頭部径Ｄ）を代入して、推定破壊角度θｅを算出する。 An estimated horizontal projected area A, which is a value obtained by dividing the acquired actually measured maximum tensile load P t by the acquired actually measured tensile strength u σ t , is calculated. That is, the estimated horizontal projection area A = P t / u σ t . Next, the calculated estimated horizontal projected area A is substituted into the equation (2) as an effective horizontal projected area Ae . Further, the (2) by substituting the conditions were performed withdrawal test (embedded length L, the head diameter D) in the expression for calculating the estimated fracture angle theta e.

上述した建築学会式では、材料２の種類（仕様）を考慮せずに推定破壊角度θを一律に４５°に設定している。即ち、建築学会式の（Ｘ）式は、本発明の（２）式において推定破壊角度θｅを４５°に設定している。一方、本発明では引抜き試験を行って、材料２の種類（仕様）毎に推定破壊角度θｅを予め把握することが、大きな特徴になっている。 In the Architectural Institute's formula described above, the estimated breaking angle θ is uniformly set to 45 ° without considering the type (specification) of the material 2. That, (X) formula Architectural Institute expression has set the estimated fracture angle theta e in 45 ° in equation (2) of the present invention. On the other hand, in the present invention by performing a pull-out tests, be grasped in advance the estimated fracture angle theta e for each type of material 2 (specification) has become a major feature.

そして、本発明では、固化した材料２に埋設されている大径頭部１ａを有するアンカー部材１を引抜く際の許容引抜き耐力Ｐｅを推定する際に、その材料２について予め把握している推定破壊角度θｅを（２）式に代入して、有効水平投影面積Ａｅを算出する。算出した有効水平投影面積Ａｅは（１）式に代入する。また、この（１）式には、予め把握しているその材料２の引張強度ｕσｔを代入することで許容引抜き耐力Ｐｅを算出、推定する。 In the present invention, when estimating the allowable pull strength P e when withdrawing the anchor member 1 having a large-diameter head portion 1a is embedded in the solidified material 2, are grasped in advance for the material 2 the estimated fracture angle θ e (2) are substituted into equation to calculate the effective horizontal projection area a e. The calculated effective horizontal projection area Ae is substituted into equation (1). Further, in the equation (1), calculating an allowable withdrawal strength P e by substituting tensile strength u sigma t of the material 2 being grasped in advance, and estimates.

このように本発明では、固化した材料２に埋設されているアンカー部材１の引抜き試験の結果と固化した材料２の引張試験の結果とに基づいて、その材料２の種類毎にその推定破壊角度θｅをより正確に把握する。それ故、材料２の種類に応じた許容引抜き耐力Ｐｅを、従来に比して一段と精度よく推定することが可能になっている。 As described above, according to the present invention, based on the results of the pull-out test of the anchor member 1 embedded in the solidified material 2 and the results of the tensile test of the solidified material 2, the estimated fracture angle for each type of the material 2 is determined. to grasp the θ e more accurately. Therefore, the allowable pull strength P e in accordance with the type of material 2, it becomes possible to estimate more accurately than conventional.

以下では、ＵＨＰ−ＳＨＣＣを材料２とした場合について、３つのシリーズに分けてアンカー部材１の引抜き試験を行い、許容引抜き耐力Ｐｅについて、その試験結果と建築学会式で算出した推定値との比較をしたので説明する。 Hereinafter, the case where the UHP-SHCC and material 2 is divided into three series perform pull tests of the anchor member 1, allowed for withdrawal Strength P e, the estimated value calculated by the Architectural Institute of formula The test results The comparison will be described.

シリーズ１では、アンカー部材１の埋込み長Ｌを１０ｍｍ〜３０ｍｍの範囲に設定し、万能試験機を用いて引抜き試験を行った。シリーズ２およびシリーズ３では、埋込み長Ｌを３０ｍｍ〜５０ｍｍの範囲に設定し、図３に例示するように、センターホールジャッキ４を有する引抜き試験機３を用いて引抜き試験を行った。   In the series 1, the embedding length L of the anchor member 1 was set in the range of 10 mm to 30 mm, and a pull-out test was performed using a universal testing machine. In the series 2 and the series 3, the embedding length L was set in a range of 30 mm to 50 mm, and a pull-out test was performed using a pull-out tester 3 having a center hole jack 4 as illustrated in FIG.

シリーズ１およびシリーズ２では図４に示すように、アンカー部材１の軸心Ｃから材料２の端面２ｂまでの最短距離Ｂ１（以下、距離Ｂ１という）を、建築学会式に基づいて算出される有効水平投影面積Ａｋを表す円環体Ｒｋの外側円の半径Ｂ３（以下、半径Ｂ３という）よりも大きく設定した試験体を用いた。シリーズ３では図５に示すように、距離Ｂ１を半径Ｂ３と同じ大きさに設定した試験体を用いた。 In the series 1 and the series 2, as shown in FIG. 4, the shortest distance B1 (hereinafter referred to as distance B1) from the axis C of the anchor member 1 to the end face 2b of the material 2 is calculated based on the Architectural Institute of Japan formula. A test specimen set to be larger than the radius B3 (hereinafter, referred to as radius B3) of the outer circle of the annular body R k representing the horizontal projection area A k was used. In the series 3, as shown in FIG. 5, a test body in which the distance B1 was set to the same size as the radius B3 was used.

シリーズ１で用いた材料２の引張強度は６．４０Ｎ／ｍｍ２であり、シリーズ２およびシリーズ３で用いた材料２の引張強度は６．１４Ｎ／ｍｍ２であった。図６〜図９に示すＥ１、Ｅ２、Ｅ３がそれぞれシリーズ１、シリーズ２、シリーズ３の試験結果である。 The tensile strength of Material 2 used in Series 1 was 6.40 N / mm 2 , and the tensile strength of Material 2 used in Series 2 and Series 3 was 6.14 N / mm 2 . E1, E2, and E3 shown in FIGS. 6 to 9 are test results of series 1, series 2, and series 3, respectively.

図４および図５に示すように、ＵＨＰ−ＳＨＣＣが材料２の場合には、アンカー材１を引抜いて形成される破壊面Ｓｔが、建築学会式で想定している破壊面Ｓｋとは大きく異なる形状になる。実際に形成された破壊面Ｓｔでは、大径頭部１ａ付近の破壊角度は４５°に近い角度となるが、材料２の上面２ａに近づくほど４５°よりも緩い破壊角度となる。 As shown in FIGS. 4 and 5, when the UHP-SHCC the material 2, fracture surface S t which is formed by pulling out the anchor member 1, a fracture surface S k assumed in Architectural Institute formula It has a very different shape. In actually formed fracture surface S t, but the fracture angle is an angle close to 45 ° in the vicinity of the large diameter head 1a, a loose broken angles than about 45 ° closer to the upper surface 2a of the material 2.

実際の破壊面Ｓｔの有効水平投射面積Ａｔ（以下、実測水平投射面積Ａｔという）を実測したところ、建築学会式に基づいて算出される有効水平投影面積Ａｋとは大きく異なっていた。シリーズ１およびシリーズ２では、実測水平投影面積Ａｔが、建築学会式に基づく有効水平投影面積Ａｋに比べて、２．７倍〜４．４倍程度大きい結果となった。 The actual fracture surface S t of the effective horizontal projection area A t (hereinafter, referred to as actual horizontal projection area A t) was measured and was significantly different from the effective horizontal projection area A k, which is calculated on the basis of the Architectural Institute of formula . In Series 1 and Series 2, measured horizontally projected area A t is compared to the effective horizontal projection area A k based on the Architectural Institute expression became 2.7 times ～4.4 times greater results.

さらに、図６に示すように、引抜き試験で実測した最大引張荷重Ｐｔ（以下、実測最大引張荷重Ｐｔという）と、建築学会式に基づいて算出した許容引抜き耐力Ｐｋ（低減係数Φを１とした場合）とを比較すると、実測最大引張荷重Ｐｔは許容引抜き耐力Ｐｋに対して２．７４倍程度大きい値となった。したがって、ＵＨＰ‐ＳＨＣＣのように、通常のコンクリートとは引張強度や靱性能が大きく異なる短繊維補強セメント材料を材料２にする場合には、建築学会式ではアンカー部材１の許容引抜き耐力を精度よく推定できない。 Furthermore, as shown in FIG. 6, the maximum tensile load P t (hereinafter, the measured maximum of tensile load P t) actually measured in the pull-out test and the allowable pull strength P k (reduction factor Φ calculated based on Architectural Institute formula comparing 1 as when) and, found the maximum tensile load P t became 2.74 times greater value the allowable withdrawal strength P k. Therefore, when a short fiber reinforced cement material having a significantly different tensile strength and toughness from that of ordinary concrete, such as UHP-SHCC, is used as the material 2, the allowable pull-out strength of the anchor member 1 is accurately determined by the Architectural Institute of Japan. Can't estimate.

一方で、図７に示すように、実測最大引張荷重Ｐｔと実測水平投影面積Ａｔとの関係を表すと、実測最大引張荷重Ｐｔと実測水平投影面積Ａｔとは線形関係にあることがわかる。これは、材料２の引張強度ｕσｔと有効水平投影面積との積から許容引抜き耐力を推定できるという建築学会式の考え方が、通常のコンクリートと引張強度や靱性能が大きく異なる短繊維補強セメント系材料２を採用した場合においても応用できることを示唆している。 On the other hand, as shown in FIG. 7, to represent the relationship between the measured maximum tensile load P t and the measured horizontal projection area A t, be in a linear relationship with the measured maximum tensile load P t and the measured horizontal projection area A t I understand. This is based on the idea of the Architectural Institute of Japan's formula that the allowable pull-out strength can be estimated from the product of the tensile strength u σ t of the material 2 and the effective horizontal projected area, but the short fiber reinforced cement is significantly different from ordinary concrete in tensile strength and toughness. This suggests that the present invention can be applied even when the system material 2 is employed.

有効水平投影面積とアンカー材１の引抜き耐力が線形関係にあるとの建築学会式の考え方によれば、実測最大引張荷重Ｐｔを実測水平投影面積Ａｔで除した値が、材料２の引張強度ｕσｔとなる。即ち、図７に示すように、横軸を実測水平投影面積Ａｔ、縦軸を実測最大引張荷重Ｐｔにしたときの実測有効水平投影面積Ａｔと実測最大引張荷重Ｐｔとの近似直線の傾きが材料２の引張強度ｕσｔを表すことになる。そして、この近似直線の傾きが表す引張強度が、シリーズ１〜３で用いた材料２の実際の引張強度ｕσｔに近い数値を示すと考えられる。 According effective horizontal projected area pulling strength of the anchor member 1 within Architectural Institute expression idea that a linear relationship, a value obtained by dividing the measured maximum tensile load P t in the measured horizontal projection area A t is the tensile of the material 2 The intensity becomes u σ t . That is, as shown in FIG. 7, the approximation of the horizontal axis measured horizontally projected area A t, the vertical axis and the measured effective horizontal projection area A t of when the measured maximum tensile load P t and the measured maximum tensile load P t linear Represents the tensile strength u σ t of the material 2. Then, tensile strength slope represents the approximate line considered to indicate a numeric value close to the actual tensile strength u sigma t of the material 2 used in Series 1-3.

しかしながら、近似直線の傾きが表す材料２の引張強度は２．４Ｎ／ｍｍ２となり、シリーズ１〜３で用いた材料２の実際の引張強度ｕσｔに比べて非常に小さい数値を示している。これは、通常のコンクリートとは引張強度や靱性能が大きく異なる短繊維補強セメント系材料２の場合には、実測有効水平投影面積Ａｔと実際の材料の引張強度ｕσｔとの積の値が実測最大引張荷重Ｐｔと一致しないことを意味している。そして、許容引抜き耐力Ｐｅに寄与しているのは実測水平投影面積Ａｔ全体ではなく、実測水平投影面積Ａｔの一部の面積であることを示唆している。 However, the tensile strength of the material 2 represented by the slope of the approximate straight line is 2.4 N / mm 2 , which is a very small value compared to the actual tensile strength u σ t of the material 2 used in the series 1 to 3. . This is because, when the normal concrete tensile strength and toughness performance is significantly different short fiber reinforced cement-based material 2, the product of the values of the tensile strength u sigma t of the actual material and the measured effective horizontal projection area A t There are means that do not match the measured maximum tensile load P t. The allowable withdrawal strength of contribute to P e, not the entire measured horizontal projection area A t, suggesting that a part of the area of the actual horizontal projection area A t.

建築学会式に基づくと、アンカー部材１の引抜き耐力に寄与する有効水平投影面積は、許容引抜き耐力を材料２の引張強度ｕσｔで除することで求められる。この建築学会式の考え方に基づいて、図８に示すように、実測最大引張荷重Ｐｔを材料２の引張強度ｕσｔにより除して算出した推定水平投影面積Ａｅと、実測水平投影面積Ａｔとの比較を行った。その結果、推定水平投影面積Ａｅは実測水平投影面積Ａｔの約０．３９倍となり、実測水平投影面積Ａｔのうち３９％程度の面積分しかアンカー部材１の引抜き耐力に寄与していないことがわかる。 According to the Architectural Institute of Japan formula, the effective horizontal projected area that contributes to the pull-out strength of the anchor member 1 is obtained by dividing the allowable pull-out strength by the tensile strength u σ t of the material 2. As shown in FIG. 8, based on the idea of the Architectural Institute of Japan, the estimated horizontal projected area A e calculated by dividing the measured maximum tensile load P t by the tensile strength u σ t of the material 2, and the measured horizontal projected area a comparison was made of the a t. As a result, the estimated horizontal projection area A e becomes approximately 0.39 times the measured horizontal projection area A t, does not contribute 39% of the area fraction only pull out strength of the anchor member 1 of the measured horizontal projection area A t You can see that.

上記の分析から、建築学会式では推定破壊角度を４５°として立式しているが、本発明では、材料２の推定破壊角度θｅを把握して、許容引抜き耐力Ｐｅに寄与する有効水平投影面積Ａｅをより精度よく推定しているので、高精度で許容引抜き耐力Ｐｅを推定可能になっている。 From the above analysis, the Architectural Institute expressions are standing formula estimated fracture angle as 45 °, in the present invention, to understand the estimated fracture angle theta e material 2, the effective horizontal contributes to allowable pull strength P e Since the projection area A e is more accurately estimated, the allowable withdrawal strength P e can be estimated with high accuracy.

図９に、本発明で推定した許容引抜き耐力Ｐｅ（低減係数Φを１とした場合）と実測最大引張荷重Ｐｔとの比較結果を示す。材料２として、ＵＨＰ‐ＳＨＣＣを用いた場合の推定破壊角度θｅは３７°以上４１°以下の範囲となり、平均すると３９°であった。そのため、図９に示す許容引抜き耐力Ｐｅは、推定破壊角度θｅを３９°として算出している。シリーズ１（Ｅ１）およびシリーズ２（Ｅ２）では、本発明で推定した許容引抜き耐力Ｐｅと実測最大引張荷重Ｐｔの数値がほぼ一致した。それ故、本発明の推定方法によって許容引抜き耐力を精度よく推定できることがわかる。 FIG. 9 shows a comparison result between the allowable pulling strength P e estimated in the present invention (when the reduction coefficient Φ is set to 1) and the measured maximum tensile load P t . As the material 2, the estimated fracture angle theta e in the case of using a UHP-SHCC becomes in the range of 37 ° or more 41 ° or less, an average for the 39 °. Therefore, the allowable withdrawal strength P e shown in FIG. 9, calculates the estimated fracture angle theta e as 39 °. In Series 1 (E1) and Series 2 (E2), numerical values of allowable withdrawal Strength P e and the measured maximum tensile load P t estimated in the present invention were almost the same. Therefore, it can be seen that the allowable pull-out strength can be accurately estimated by the estimation method of the present invention.

シリーズ３（Ｅ３）においては、本発明で推定した許容引抜き耐力Ｐｅが、実測最大引張荷重Ｐｔよりも若干大きい数値を示した。図７に示すように、有効水平投影面積Ａｅを材料２に埋設されたアンカー部材１の軸心Ｃを中心として、大径頭部１ａの外周側に広がる円環体Ｒｅの面積と仮定すると、シリーズ３では、円環体Ｒｅの外側円の半径Ｂ２が距離Ｂ１よりも大きい条件となっている。 In Series 3 (E3), the allowable pull strength P e estimated by the present invention showed a slightly larger number than the measured maximum tensile load P t. As shown in FIG. 7, around the axis C of the anchor member 1 embedded effective horizontal projection area A e to the material 2, assuming that the area of the annular body R e extending to the outer peripheral side of the large-diameter head portion 1a Then, the series 3, the radius B2 outer circle of the torus R e is a greater condition than the distance B1.

このように、距離Ｂ１よりも半径Ｂ２が大きい場合には、有効水平投影面積Ａｅに相当する円環体Ｒｅのうち、材料２の端面２ｂよりも外側にはみ出した部分は、実際には引抜きに寄与しない部分となる。 As described above, when the radius B2 is larger than the distance B1, the portion of the toroid R e corresponding to the effective horizontal projection area A e that protrudes outside the end surface 2b of the material 2 is actually This is a part that does not contribute to pulling.

そのため図５に示すように、半径Ｂ２が距離Ｂ１よりも大きいときには、（１）式により算出される許容引抜き耐力Ｐｅを減ずる補正を行なうとよい。具体的には、例えば、有効水平投影面積Ａｅに相当する円環体Ｒｅにおいて、円環体Ｒｅ全体に対して材料２の端面２ｂよりも外側にはみ出した部分の面積比率を求める。そして、この外側にはみ出した部分の面積比率分を（１）式により算出される許容引抜き耐力Ｐｅから減ずる補正を行なう。 Therefore, as shown in FIG. 5, when the radius B2 is greater than the distance B1 may when performing correction to reduce the allowable pull strength P e calculated by equation (1). Specifically, for example, effective in torus R e corresponding to the horizontal projection area A e, determine the area ratio of the portion protruding outside the end face 2b of the material 2 for the entire torus R e. Then, a correction to reduce the area ratio amount of the portion protruding to the outer side (1) from the allowable pull strength P e calculated by the equation.

本発明を用いることで、通常のコンクリートと引張強度や靱性能が大きく異なる短繊維補強セメント材料を材料２とした場合に、従来に比して、高精度で引抜き耐力Ｐｅを推定できる。そして、本発明は、事前に材料２の推定破壊角度θｅを把握しておけば、アンカー部材１の埋設条件を（１）式に代入するだけで、許容引抜き耐力Ｐｅを算出することができるので、非常に有益性が高い。 By using the present invention, when tensile ordinary concrete strength and toughness performance has been greatly different short fiber reinforced cement material as 2, compared to the conventional, it can be estimated withdrawal strength P e with high accuracy. The present invention, if in advance grasp the estimated fracture angle theta e material 2, only substituting the buried condition of the anchor member 1 (1), is possible to calculate the allowable pull strength P e Can be very useful.

１ アンカー部材
１ａ 大径頭部
２ （短繊維補強セメント系）材料
２ａ 上面
２ｂ 端面
３ 引抜き試験機
４ センターホールジャッキ
Ｓｔ 実際の破壊面
Ｓｋ 建築学会式で推定した破壊面
Ｓｅ 本発明で推定した破壊面 1 anchor member 1a large diameter head 2 (short fiber reinforced cement) material 2a top 2b end surface 3 pull tester 4 center fracture surface S e present invention was estimated by Hall jack S t actual fracture surface S k Architectural Institute formula Estimated fracture surface

Claims (4)

固化した短繊維補強セメント系材料に埋設されている大径頭部を有するアンカー部材を引き抜く際の許容引抜き耐力Ｐｅを下記（１）式を用いて推定する方法であって、
Ｐｅ＝Φ・ｕσｔ・Ａｅ・・・（１）
ここで、Φは低減係数、ｕσｔは前記材料の引張強度、Ａｅは下記（２）式より算出される有効水平投影面積であり、
Ａｅ＝π（Ｌ／ｔａｎθｅ）｛（Ｌ／ｔａｎθｅ）＋Ｄ｝・・・（２）
ここで、Ｌは前記アンカー部材の埋込み長、Ｄは前記大径頭部の頭部径、θｅは推定破壊角度であり、
固化した前記材料に埋設されている前記アンカー部材の引抜き試験により取得した実測最大引張荷重を、固化した前記材料の引張試験により取得した実測引張強度により除して算出された値を、前記有効水平投影面積Ａｅとして前記（２）式に代入して前記引抜き試験の条件に基づいて推定破壊角度θｅを予め把握しておき、
前記許容引抜き耐力Ｐｅを推定する際に、予め把握した前記推定破壊角度θｅを代入した前記（１）式を用いることを特徴とする短繊維補強セメント系材料に埋設されたアンカー部材の許容引抜き耐力の推定方法。 The allowable pull strength P e when removing the anchoring member having a large-diameter head portion is embedded in the solidified short fiber reinforced cement-based material A method for estimating using the following equation (1),
P e = Φ · u σ t · A e (1)
Here, Φ is the reduction coefficient, u σ t is the tensile strength of the material, A e is the effective horizontal projected area calculated from the following equation (2),
A e = π (L / tan θ e ) {(L / tan θ e ) + D} (2)
Here, L is embedded length of the anchor member, D is the head diameter of the large-diameter head, theta e is an estimated fracture angle,
A value calculated by dividing the actually measured maximum tensile load obtained by the pull-out test of the anchor member embedded in the solidified material by the actually measured tensile strength obtained by the tensile test of the solidified material, By substituting the projected area A e into the above equation (2) and grasping the estimated breaking angle θ e in advance based on the conditions of the pull-out test,
When estimating the allowable pull-out strength P e , the above equation (1) in which the previously estimated estimated breaking angle θ e is substituted is used, wherein the allowable value of the anchor member embedded in the short fiber-reinforced cementitious material is used. Method for estimating pullout strength. 前記材料がＵＨＰ‐ＳＨＣＣである請求項１に記載の短繊維補強セメント系材料に埋設されたアンカー部材の許容引抜き耐力の推定方法。   The method for estimating the allowable pull-out strength of an anchor member embedded in a short fiber reinforced cementitious material according to claim 1, wherein the material is UHP-SHCC. 前記推定破壊角度θｅが３７°以上４１°以下の範囲である請求項２に記載の短繊維補強セメント系材料に埋設されたアンカー部材の許容引抜き耐力の推定方法。 Estimation method allowable withdrawal strength of the estimated fracture angle theta e anchor member embedded in the short fiber-reinforced cement-based material according to claim 2 in the range of 37 ° or more 41 ° or less. 前記許容引抜き耐力Ｐｅを推定する際に、前記推定破壊角度θｅを代入した前記（２）式により算出される前記有効水平投影面積Ａｅが、材料に埋設されたアンカー部材の軸心を中心としてその大径頭部の外周側に広がる円環体の面積と仮定した場合に、この円環体の外側円の半径が、このアンカー部材の軸心からこの材料の端面までの距離よりも大きいときは、前記（１）式により算出される許容引抜き耐力を減ずる補正を行なう請求項１または２のいずれかに記載の短繊維補強セメント系材料に埋設されたアンカー部材の許容引抜き耐力の推定方法。 When estimating the allowable pull-out strength P e , the effective horizontal projected area A e calculated by the expression (2) into which the estimated breaking angle θ e is substituted is determined by the axial center of the anchor member embedded in the material. Assuming that the area of an annular body extending to the outer peripheral side of the large diameter head as the center, the radius of the outer circle of the annular body is larger than the distance from the axis of the anchor member to the end face of the material. When the value is larger, the allowable pull-out strength calculated by the equation (1) is corrected to reduce the allowable pull-out strength, and the allowable pull-out strength of the anchor member embedded in the short fiber reinforced cementitious material according to claim 1 or 2, is estimated. Method.
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