JP4278149B2 - Shaped steel and wall body using the shaped steel - Google Patents

Description

  The present invention relates to a structural steel applicable to the civil engineering and construction fields, and a wall body using the structural steel.

  As a steel / concrete composite structure, for example, there is a structure in which protrusions are provided on the surface of an H-shaped steel and concrete is adhered around the H-shaped steel. As such an H-shaped steel with a protrusion, one having a protrusion on the inner surface of the flange is known (see, for example, Patent Document 1).

On the other hand, as a wall body using a shape steel as a core material, for example, as shown in FIG. 27, there is an SRC wall body using an H-section steel 101. The wall body shown in FIG. 27 has a horizontal reinforcing bar 104 laid on both sides of the concrete 103 in a direction transverse to the wall body, and a main body laid in a vertical direction on the wall body so as to cross the horizontal reinforcing bar 104. It has a reinforcing bar 105, and an H-section steel 101 is arranged at the center of the wall.
In this wall body, the concrete 103, the horizontal reinforcing bar 104, and the main reinforcing bar 105 are integrated to form a steel / concrete structure. However, the H-shaped steel 101 and the concrete 103 are not adhered to each other, and the H-shaped. The steel 101 and the concrete 103 are not integrated.
Japanese Patent Publication No. 1-55042

  In the above Patent Document 1, there is only a description that it is desirable to provide protrusions on the inner surface of the H-shaped steel in order to increase the binding force with concrete, and what protrusions are provided in any arrangement. There is no disclosure as to whether it is desirable to increase adhesion to concrete. In fact, it has been found by the inventor's research that even if protrusions are provided on the inner surface of the shape steel, sufficient adhesion cannot be obtained depending on the size and arrangement of the protrusions.

In the wall shown in FIG. 27, a steel / concrete composite structure is formed between the horizontal reinforcing bar 104 and the main reinforcing bar 105 and the concrete 103, and a certain amount of concrete is provided around the horizontal reinforcing bar 104 and the main reinforcing bar 105. 103 is required. Therefore, a certain amount of the distance B10 shown in FIG. 27 is required, and as a result, there is a problem that the thickness A10 of the wall body increases.
In recent years, in the civil engineering and architecture fields, in order to increase the effective usable area, it has been directed to reduce the wall thickness of underground walls and building structural walls. It is difficult to reduce the wall thickness while maintaining the strength of the body.
Accordingly, an object of the present invention is to obtain an H-shaped section steel and a wall body that can reduce the wall thickness.

(1) In order to increase the adhesion to the shape steel, the shape steel according to the present invention is an H-shaped shape steel having a plurality of protrusions on the flange inner surface side, and the shape steel surface on which the protrusions are formed. The upper side width b _{2 of} the protrusion, the protrusion height h, and the protrusion pitch P in the vertical cross section satisfy the following expression.
P / h ≦ 10 and P / b ₂ ≧ 4
Hereinafter, the basis of the above formula will be described. First, the grounds for P / h ≦ 10 will be described, and then the grounds for P / b ₂ ≧ 4 will be described.

(A) Grounds for P / h ≦ 10 FIG. 18 shows an example of a protrusion cross section perpendicular to the shaped steel surface on which the protrusion is formed, FIG. 18 (a) shows a protrusion having a trapezoidal cross section, and FIG. b) shows a protrusion having a rectangular cross section.
In steel / concrete structures, what is indispensable in order to achieve high yield strength and rigidity is to integrate the two and obtain a structure that balances the acting external force between steel and concrete. The integration of steel and concrete is a structure in which stress can be exchanged between steel and concrete, and for that purpose, it is necessary to have sufficient adhesion (performance) between steel and concrete.

The adhesion force between the shape steel with protrusions and the concrete is generated by the engagement of the protrusions formed on the inner surface of the shape steel with the concrete, and depends on the bearing failure τ ₁ or the shear failure τ ₂ of the concrete.
Here, the bearing failure τ ₁ is a shear strength determined by the bearing failure of the concrete in front of the protrusion, and τ ₂ is a shear strength determined by the shear failure at the boundary between the protrusion and the concrete.
Then, when the bearing failure τ ₁ and the shear failure τ ₂ are expressed by general model equations, the following equations are obtained.

As described above, the adhesive force tau _1, depends on tau _2, tau _1, of the tau _2, since smaller value becomes a bottleneck for the adhesion strength between steel and concrete, which is between the steel and concrete The degree of adhesion stress τ _max . Therefore, it is necessary to obtain the degree of adhesion stress τ _max in order to examine the conditions for increasing the adhesion strength.
In order to obtain the adhesion stress degree τ _max , it is necessary to compare τ ₁ and τ _2, and therefore the following assumption is made.
(Assumption 1)
The following equation is assumed as the relationship between the uniaxial compressive strength σ _c and the shear strength τ _c of concrete that is usually used as a construction material (approximate to design criteria).
τ _c = 0.1 × σ _c ------------------- (3)

FIG. 19 shows the relationship between τ ₁ and τ ₂ and P / h based on the above assumption. The smaller value of the two fracture types is the steel-concrete bond stress τ _{max. From} the graph above, however, the concrete fracture is the shear fracture type in the region below about P / h = 10. τ ₂ ), and τ _max does not change greatly. On the other hand, when the τ _max is exceeded, rupture of the concrete becomes a bearing failure type (depending on τ ₁ ), and the decrease in τ _max becomes remarkable. Therefore, in order to ensure a large adhesive force, it is desirable that the concrete fracture be a shear fracture type region.
Therefore, in consideration of the variation in the relationship between the uniaxial compressive strength σ _{c of} concrete and the shear strength τ _c , the condition is that the following formula is satisfied as the protrusion pitch at which a stable adhesion stress τ _max is obtained.
P / h ≦ 10 ------------------------ (4)

(A) Grounds for P / b ₂ ≧ 4 The shear failure between steel and concrete occurs mainly on the boundary line between the concrete and the upper side b ₂ of the protrusion (see FIG. 20). Generally, as the proportion of concrete that is on the boundary line is large (i.e., the larger the proportion of the upper b ₂ is small), the shear strength increases.
The effect of the ratio between the protrusion pitch P and the protrusion upper side width b ₂ on the steel-concrete shear strength τ ₂ can be evaluated by the following equation.
τ ₂ = (P−b ₂ ) / P · τc ------------------------ (5)
τc: Concrete shear strength Equation (5) expresses the shear strength τ ₂ taking into account the strength reduction due to the loss of the concrete shear fracture surface length of the protrusion upper side width b ₂ minutes. Multiplying the surface length loss rate (P−b ₂ ) / P can be expressed as τ ₂ .

When τc in equation (5) is shifted to the left side, τ ₂ / τc = (P−b ₂ ) / P is obtained. FIG. 21 is a graph showing this relationship. From FIG. 21, it can be seen that in the region where P / b ₂ is less than 4, the shear strength τ ₂ rapidly decreases.
Further, FIG. 22 shows the relationship between the incremental change rate (first derivative) of τ ₂ / τc and P / b ₂ . FIG. 22 shows that the incremental change rate saturates in the region where P / b ₂ is 4 or more.
From the above, the relationship between the protrusion pitch P and the protrusion upper side width b ₂ for maintaining a stable degree of adhesion stress needs to satisfy the following expression.
P / b ₂ ≧ 4 ------------------------ (6)

(2) The shape steel according to the present invention is an H-shaped shape steel having a plurality of protrusions on the flange inner surface side, and the upper side width b ₂ of the protrusion in a cross section perpendicular to the shape steel surface on which the protrusion is formed. The protrusion height h and the protrusion pitch P satisfy the following formula.
2 mm ≦ h ≦ 50 mm and 4b ₂ ≦ P ≦ 10 h

The reason why the projection height h is in the above range is as follows.
If the height is less than 2 mm, it is difficult to ensure reliable adhesion with concrete due to the adhesion of impurities called slime to the projections and corrosion of the projections when underwater concrete is placed like an underground wall. Therefore, 2 mm was set as the lower limit.
On the other hand, if the height of the protrusion exceeds 50 mm, there is a high possibility that it becomes an obstacle when inserting or lifting the tremmy tube.

  However, when rolling and manufacturing, the upper limit of the protrusion height is preferably 5 mm. This is because, in order to form a projection height of 5 mm or more by rolling, an excessive rolling load is required, which is not economical. Moreover, when attaching a protrusion by welding etc., such as steel bar, a square, etc., it is preferable that the protrusion height has a lower limit of 9 mm. This is because if the height of the protrusion is smaller than 9 mm, the welding attachment work is complicated and the number of attachments increases, which is not realistic.

Note that 4b ₂ ≦ P ≦ 10h that defines the range of the protrusion pitch P becomes P / h ≦ 10 and P / b ₂ ≧ 4 when this is broken down into two equations. And the grounds prescribed | regulated to this relationship are as having demonstrated in said (1).

(3) The shape steel according to the present invention is an H-shaped shape steel having a plurality of protrusions on the flange inner surface side, and a lower side width b ₁ of the protrusion in a cross section perpendicular to the shape steel surface on which the protrusion is formed. The protrusion height h and the protrusion pitch P satisfy the following formula.
2 mm ≦ h ≦ 50 mm and 4b ₁ ≦ P ≦ 10 h

In the above relationship, the reason why 4b ₁ ≦ P is as follows. Considering the strength of the protrusion, the relationship between the upper side width b ₂ of the protrusion and the lower side width b _{1 of the} protrusion is 1 ≦ b ₁ / b ₂ is preferable. Then b ₁ / b ₂
The lower limit of is 1. Therefore, it is possible to use a lower side width b ₁ of the protrusions in place of the upper side width b ₂ of the protrusions in 4b ₂ ≦ P above (2), the lower side width b of the protrusion of the upper side width b ₂ of the protrusions in the above (2) that instead of ₁ is the 4b ₁ ≦ P.

When the protrusion cross section is a rectangle shown in FIG. 18B, b ₂ = b ₁ = b.
In addition, the protrusion can be formed by rolling or the like, but in that case, the cross-sectional shape or the like is not necessarily an ideal trapezoid or rectangle as shown in FIGS. 18 (a) and 18 (b). Absent. For example, as in the case of the protrusion shown in FIG. 23, the cross-sectional shape may be different depending on the location in the case of a curved substantially triangular shape whose height decreases toward the tip.
In such a case, a representative value may be provided and evaluated, and applied to the conditional expressions of the present invention shown in the above (1) to (3). For example, in the example shown in FIG. 23, representative values may be provided as follows (see FIG. 24).
(A) Projection height h: Height value at the 1 / 2L point from the projection root (web side) (L: Projection length (distance from the projection root to the projection tip))
(B) Projection width b1: Value of the lower side at the 1 / 2L point from the projection root (web side) (C) Projection width b2: Value of the upper side at the 1 / 2L point from the projection root (web side) (D) Projection pitch P : Distance between center position of protrusion (width direction) at 1 / 2L point from protrusion root (web side)

In addition, the protrusion height h was evaluated by the value of the lower side at the 1 / 2L point from the protrusion root (web side). The effective bearing area (projected area of the protrusion side surface) of the concrete and the steel material at this point is a square shape. Because it becomes equal to the case.
As for the protrusion widths b1 and b2 and the protrusion pitch P, the effective concrete shear length (concrete length between adjacent protrusions) of the concrete and the steel material is a square shape at a point 1 / 2L from the protrusion root (web side). Because it becomes equal.

(4) The structural steel in the present invention is an H-shaped structural steel that is used as a structural member of a steel / concrete wall body by standing a plurality of web surfaces facing each other in the longitudinal direction of the wall body. A plurality of protrusions on the side, and an upper side width b ₂ , a protrusion height h, and a protrusion pitch P in the cross section perpendicular to the H-shaped steel surface on which the protrusions are formed satisfy the following formula: It is.
P / h ≦ 40 and P / b ₂ ≧ 4
Among the above numerical limitations, the basis for setting P / b ₂ ≧ 4 is as described in (1) above. In the following, the grounds for setting P / h ≦ 40 will be described.

Steel according to projections of the H-beam - deposition stresses tau _max between concrete, the strength at the concrete Bearing Failure Type (tau _1), in comparison with the strength at the concrete shear failure format (tau _2), both It is defined as the smaller of these values.
When τ ₁ and τ ₂ are expressed by general model equations, as described above, the following is obtained.

When the H-shaped steel with protrusions is actually embedded in concrete and used as a wall body, the web surfaces are opposed to each other and continuously arranged (see FIG. 25).
In this structure, the strength of the adjacent H-section steel is increased because the deformation of the internal concrete is constrained by the web surface and the flange surface. Therefore, the strength of adhesion stress τ ' _max between steel and concrete used in actual is the additional factor α of strength for τ ₁ and τ ₂ above: α ₁ : Additional factor for bearing failure due to the restraining effect between flanges α ₂ : Between flanges The value α ₁ · τ ₁ and α ₂ · τ ₂ , which are multiplied by an additional coefficient for shear failure due to the constraint effect, are defined as the smaller value of the two.

When H-section steel is used as the wall, calculating the percent increment based on the experimental results leads to α ₁ = 10 and α ₂ = 3, respectively.
Here, in order to compare both α ₁ · τ ₁ and α ₂ · τ ₂ , the above-described assumption of τc = 0.1 × σc is made. Based on this assumption, α ₁ × τ ₁ and α ₂ × τ ₂ The relationship of P / h is as shown in FIG.
Although smaller one of the two fracture type is adhered stresses tau _'max between the steel and concrete, approximately boundary P / h = 42 from the graph, less concrete failure shear fracture in the region format (Depends on τ ₂ ), and τ ′ _max does not change greatly. On the other hand, when the τ ′ _max is exceeded, the fracture of the concrete becomes a bearing failure type (depending on τ ₁ ), and the decrease in τ ′ _max becomes remarkable. Therefore, in order to ensure a large adhesive force, it is desirable to determine the protrusion pitch so that the concrete fracture becomes a shear fracture type region.
From this relationship, in terms of even dispersion of the relationship between the uniaxial compression strength σc and shear strength τc of concrete considering, as a stable shape of the projection pitch bond stress of tau _'max is obtained, and a P / h ≦ 40.

(5) A structural steel according to the present invention is an H-shaped structural steel that is used as a structural member of a steel / concrete wall body by standing a plurality of web surfaces facing each other in the longitudinal direction of the wall body. A plurality of protrusions are provided on the inner surface side, and the upper side width b ₂ , the protrusion height h, and the protrusion pitch P of the protrusions in a cross section perpendicular to the H-shaped steel surface on which the protrusions are formed satisfy the following expression. Is.
2 mm ≦ h ≦ 50 mm and 4b ₂ ≦ P ≦ 40 h

The reason why the projection height h is set to 2 mm ≦ h ≦ 50 mm is as described in (2) above. Further, 4b ₂ ≦ P ≦ 40h, which defines the protrusion pitch P, is divided into two equations and arranged, and P / h ≦ 40 and P / b ₂ ≧ 4. The basis of P / h ≦ 40 is as described in (4) above, and P / b ₂ ≧ 4 is as described in (1) above.

(6) A structural steel according to the present invention is an H-shaped structural steel which is used as a structural member of a steel / concrete wall body by standing a plurality of web surfaces facing each other in the longitudinal direction of the wall body. A plurality of protrusions are provided on the inner surface side, and the lower side width b ₁ , the protrusion height h, and the protrusion pitch P of the protrusions in a cross section perpendicular to the H-shaped steel surface on which the protrusions are formed satisfy the following expression. Is.
2 mm ≦ h ≦ 50 mm and 4b ₁ ≦ P ≦ 40 h

The reason why the projection height h is set to 2 mm ≦ h ≦ 50 mm is as described in (2) above. Further, 4b ₁ ≦ P ≦ 40h is obtained by replacing the upper side width b ₂ of the protrusion in the above (5) with the lower side width b ₁ , and the basis for this alternative is as described in the above (3).

(7) The shape steel according to the present invention is characterized in that in the shape steel described in (1) to (6) above, an adhesion strengthening means is provided on the web surface.
The adhesion reinforcing means provided on the web surface may be a protrusion or a recess. In the case of protrusions, the above conditions (1) to (6) may be satisfied or may not be satisfied. In any case, by providing the adhesion strengthening means on the web surface, the adhesion can be improved in combination with the protrusions provided in the above (1) to (6).

(8) The shape steel according to the present invention is characterized in that, in the shape steel described in (1) to (7) above, h ≦ b ₁ when the lower side width of the protrusion is b _1. It is.

The reason why h ≦ b ₁ is set is that the protrusion height h is at least equal to or greater than the protrusion width lower side b ₁ because the protrusion may be deformed to reduce the effect of preventing concrete from slipping.
The above explanation is about the lower side b ₁ of the protrusion width, but if the upper side b ₂ of the protrusion width is too wide, it causes a reduction in the shear area with the concrete (decrease in shear stress), so a certain restriction is necessary. It becomes. However, this point does not need to be newly added because 4b ₂ ≦ P is already provided as a limiting equation for preventing the reduction of the shear stress τ _{2 in} the above (2).

(9) In the shape steel according to the present invention, in the shape steel described in (1) to (8) above, the protrusions are provided on the flange inner surface and the web surface, and the protrusions provided on both are integrated. It is characterized by this.

(10) A wall according to the present invention is a wall using the structural steel according to any one of (1) to (9) as a structural member, and the structural steel has a flange outer surface facing a wall surface. A plurality of the wall bodies are provided in the longitudinal direction.

(11) Further, in the above (10), adjacent shape steels are connected to each other by a connecting member.

(12) Further, in the above (10), horizontal reinforcing bars are arranged at a plurality of locations in the wall body height direction in contact with the outer surface of the flange of the shaped steel.

(13) Further, in the above (12), the main reinforcing bars are arranged between the flanges of the adjacent shape steels and inside the horizontal reinforcing bars so as to contact the horizontal reinforcing bars and cross in a cross shape. It is a feature.

(14) Further, in the above (12) or (13), the horizontal reinforcing bar is fixed to the outer surface of the flange of the shape steel.

  In the present invention, since a plurality of protrusions are provided on the inner surface side of the shape steel, and these protrusions are set so as to satisfy a predetermined numerical value, the adhesion force with concrete can be increased. As a result, the wall thickness can be reduced by using such a shaped steel as a structural member of the wall.

[Embodiment 1]
FIG. 1 is an explanatory view of a H-shaped steel 1 with protrusions according to Embodiment 1 (reference example) , FIG. 1 (a) is a schematic plan view, and FIG. 1 (b) is a XX partial cross-sectional view. .
As shown in FIG. 1, the H-section steel 1 with protrusions according to the first embodiment has protrusions 2 having a rectangular cross section on the four surfaces of the flange inner surface. Formed. The protrusion 2 on the inner surface of the flange has a protrusion height h1, a protrusion width b, and a protrusion length L1, and is formed without being in contact with a corner formed by the flange and the web.

As for the shape and arrangement of the protrusions, the protrusion pitch P is set to 4b ≦ P ≦ 40h1 and the protrusion height h1 is set to 2mm ≦ h1 ≦ 50mm in order to increase the adhesion between the concrete and the solidified soil. Yes. Further, the protrusion 2 is formed so that the protrusion longitudinal direction is parallel to the flange width Wf direction.
If the protrusions 2 are parallel to the flange width direction, the adhesion characteristics generated in either direction are the same, and there is no difference in strength and stable adhesion performance can be obtained. On the other hand, if the direction of the protrusion has an inclination with respect to the flange width direction, the characteristics may differ depending on the direction of adhesion, but the protrusion obtained by rolling forming has a shape with an inclination in one direction. However, the difference in characteristics depending on the direction of adhesion was negligible.

[Embodiment 2]
2A and 2B are explanatory diagrams of the H-shaped steel 11 with protrusions according to the second embodiment (reference example) , FIG. 2A is a schematic plan view, and FIG. 2B is a partial cross-sectional view taken along line XX. .
As shown in FIG. 2, the H-shaped steel 11 with protrusions according to the second embodiment has protrusions 2 having a rectangular cross section formed on the four surfaces of the flange inner surface in the same manner as the protrusions 2 according to the first embodiment. At the same time, protrusions 2A as adhesion enhancing means are formed on both surfaces of the web at a plurality of locations in the H-shaped steel longitudinal direction, with the longitudinal direction of the protrusion being the web height direction.

  The projection 2A on the web surface is formed on each surface of the web, has a projection height h2, a projection width b, and a projection length L2. Both the projection 2 on the flange inner surface and the projection 2A on the web surface are composed of a flange and a web. It is formed without contacting the corners. The protrusion height h2, protrusion width b, and protrusion length L2 of the protrusion 2A formed on the web surface can be uniquely determined with respect to the protrusion 2 formed on the inner surface of the flange.

As to the shape and arrangement of the protrusions formed on the web surface, as in the first embodiment, the protrusion pitch P is 4b ≦ P ≦ 40h2 and the protrusion height is increased in order to increase the adhesion between concrete and solidified soil. The height h2 is preferably set so as to satisfy 2 mm ≦ h2 ≦ 50 mm.
However, if most of the adhesive force required by the protrusion formed on the flange surface can be ensured, the protrusion formed on the web surface is positioned as an auxiliary increase in adhesive force, and in that case, the above-mentioned is not necessarily the case. It is not necessary to satisfy the shape and arrangement.

[Embodiment 3]
FIG. 3 is an explanatory diagram of the H-shaped steel 21 with protrusions according to the third embodiment of the present invention. As shown in FIG. 3, the H-shaped steel 21 with projections according to the third embodiment has projections 2 having a projection height h1, a projection width b, and a projection length L1 formed on four surfaces of the flange inner surface on the flange inner surface. And a protrusion 2B having a protrusion height h2, a protrusion width b, and a protrusion length L3 is formed on the web surface. Further, the protrusion 2 on the inner surface of the flange and the protrusion 2B on the web surface are both formed in contact with the corner portion formed by the flange and the web, and the protrusion 2B on the web surface is not formed at the center of the web surface.
By the contact of the corners described above, the adhesion force between the concrete and the solidified soil can be further increased (integration effect). The protrusion length L3 of the protrusion 2B formed on the web surface of the H-shaped steel 21 with protrusions according to the third embodiment is formed on the web surface of the H-shaped steel 11 with protrusions according to the second embodiment. The length is set shorter than the protrusion length L2 of the protrusion 2A.
The shape and arrangement of the protrusions, that is, the protrusion pitch P, the protrusion width b, and the protrusion heights h1 and h2 are the same as those in the first and second embodiments.

  The H-shaped steels 1, 11, 21 with protrusions according to the above-described first to third embodiments show the case where the protrusion 2 has the protrusion longitudinal direction parallel to the flange width direction. As described above, as steel, even if the protrusion 2 is formed to be inclined with respect to the flange width direction, a constant adhesion can be obtained.

  In addition, the method of forming the protrusion 2 shown in the first embodiment on the inner surface of the flange may be formed by rolling, or using a protrusion member such as a square bar, a round bar, a deformed reinforcing bar, a stud, etc., to a predetermined length. You may form by cut | disconnecting and adhering to a flange inner surface. When the protrusion 2 is formed of a protrusion member, the protrusion member is preferably made of steel so that the protrusion 2 can be easily fixed. The protrusions 2A and 2B can be formed in the same manner as the protrusion 2.

[Embodiment 4]
FIG. 4 is an explanatory view of a wall body according to Embodiment 4 of the present invention, and shows a horizontal section when the wall body is erected.
As shown in FIG. 4, the wall body according to the fourth embodiment is a wall body using the H-shaped steel 1 with projections shown in the first embodiment as a structural member, and the H-shaped steel with projections as the structural member. 1 (FIG. 4 (a)), in addition to the H-shaped steel 1 with protrusions, a horizontal rebar 4 is used as a structural member (FIG. 4 (b)), and a vertical rebar 5 is added as a structural member. The thing (FIG.4 (c)) is shown.

In the wall shown in FIG. 4 (a), the H-shaped steel 1 with protrusions is excellent in adhesion to concrete or solidified soil, so the H-shaped steel 1 and concrete or solidified soil are integrated, Steel / concrete structure is constructed in which tensile force is mainly borne by steel and compressive force is borne mainly by concrete.
As a result, in the case of the conventional example in which adhesion between the H-shaped steel and the concrete is not taken (see FIG. 27), it was necessary to take adhesion between the reinforcing bars 104 and 105 to form a steel / concrete structure. In the present embodiment, it is not necessary to arrange the reinforcing bars 104 and 105 in order to take adhesion with concrete or the like, or to arrange concrete having a predetermined thickness or more around them. And since the protrusion is formed in the inner surface side of a flange, the concrete etc. for taking adhesion with the H-section steel 1 are not required on the flange outer surface.
As a result, the interval B1 from the flange outer surface to the wall surface of the H-shaped steel 1 with projections can be made smaller than the interval B10 from the flange outer surface to the wall surface in the conventional example, and the wall thickness can be reduced.
Further, since the proof stress of the structure itself is increased, the wall thickness can be reduced in that sense.

  Moreover, since the wall body of this Embodiment has arrange | positioned the several H-section steel 1 with the web surface facing, the restraint effect of the concrete between the flanges of each H-section steel 1 becomes the wall body width direction full length. We can expect across and can increase adhesion more. That is, as shown in FIG. 5 (a), when there is nothing next to the H-section steel 1, when the concrete is cracked, the concrete constrained between the flanges is separated in the horizontal direction in the figure. Adhesion is greatly reduced. On the other hand, as shown in FIG. 5 (b), when the H-section steels 1 are arranged with the web surfaces facing each other, the concrete sandwiched between the flanges of the respective H-section steels 1 tends to be separated. Occasionally adjoining neighbors prevent this from happening. For this reason, adhesive force can be maintained and the proof stress fall of a wall can be prevented.

The maximum adhesion stress _τ'max (N / mm ² ) for concrete of a wall body in which a plurality of H-shaped steels 1 with protrusions are erected is obtained when there is no restriction between flanges (that is, when there is only one steel with a protrusion). On the other hand, it is 2.7-25 times.

  In addition, in the wall body using the H-shaped steel 1 with projections as a structural member, if the distance between the centers of the adjacent H-shaped steels 1 with projections is excessively increased, the proof stress and the rigidity are extremely reduced. In the wall, there is a possibility that concrete punching (a kind of brittle fracture) may occur, and the effect of reducing the wall thickness is reduced. Therefore, it is desirable to set the distance between the centers of the adjacent H-section steels 1 with protrusions within a range of 1.0 to 2.5 times the flange width according to the force applied to the wall.

In addition, when constructing an underground wall, a pipe called a tremy tube (generally having a diameter of 200 to 250 mm) can be inserted between the adjacent H-shaped steels 1 with projections, while achieving a sufficiently thin wall. Therefore, it is desirable to use the H-shaped steel with projection 1 having a web height of 600 mm or more, a flange width Wf of 300 mm or more, and a steel yield point of 315 N / mm ² or more.

  Next, the wall structure of FIG. 4B will be described. As described above, this wall body is one in which the horizontal reinforcing bars 4 are arranged at a plurality of positions in the wall body height direction in contact with the flange outer surface of the H-shaped steel 1 with projections. In the case shown in FIG. 4B, the resistance to bending in the orthogonal direction can be increased in the horizontal reinforcing bars 4 acting on the wall body.

  In addition, in the wall structure of FIG.4 (b), the horizontal reinforcement 4 is an auxiliary structural member, and compared with the case where attachment of the concrete 103 and the reinforcement 104 is essential as shown in FIG. The interval B2 from the outer surface of the flange to the wall surface can be reduced.

Next, the wall structure of FIG. 4C will be described. As described above, in addition to the horizontal rebar 4, the wall body has the main rebar 5 between the flanges of the adjacent H-shaped steel 1 with projections and in contact with the inside of the horizontal rebar 4 and crossing in a cross shape. It is arranged.
In this wall body, it is possible to increase the resistance to bending in the orthogonal direction to the main reinforcing bars 5 acting on the wall body.

  Moreover, in this wall body, since the main reinforcement 5 was arrange | positioned inside the horizontal reinforcement 4, the space | interval B3 from a flange outer surface to a wall surface does not become large by arrange | positioning the main reinforcement 5, but wall thickness as a whole. Can be thin.

In addition, in the wall body of this Embodiment 4, the erection accuracy of an H-section steel member can be raised by connecting adjacent H-section steel 1 with a protrusion at the time of wall construction.
For example, in the wall structure shown in FIG. 4 (a), for example, flat steel is used as the connecting member, and when the wall is constructed, the flat steel is fixed to the flange of the H-shaped steel 1 with protrusions by welding. It can be set as the wall body by which the adjacent H-section steels 1 are connected by the flat steel fixed to the H-section steel 1.
In the wall structure shown in FIGS. 4 (b) and 4 (c), the adjacent H-shaped steels 1 with protrusions adjacent to each other in the steel structure portion are welded to the flange surface by welding the horizontal reinforcing bars 4 during the construction of the wall. It can be set as the wall body which is connected.

  Such a wall body in which adjacent H-section steels 1 are connected to each other by a connecting member or a horizontal reinforcing bar 4 is subjected to uneven force in the longitudinal direction of the wall body, for example, an earth pressure in the case of an underground wall. Even so, the force can be propagated in the lateral direction by the connecting member, and the restraining force of the concrete that is in contact with the web surface of the adjacent H-shaped steel 1 with projections and sandwiched between the flange inner surfaces can be further increased.

  In addition, as the horizontal reinforcement 4 and the main reinforcement 5, if an appropriate deformed reinforcement is used, the adhesive force with concrete etc. can be increased, and it is more preferable.

In the fourth embodiment, the H-shaped steel 1 with protrusions shown in the first embodiment has been described as an example. However, the H-shaped steels 11 and 21 shown in the second and third embodiments are structured. Needless to say, a wall can be constructed as a member.
And when a wall body is constructed using the H-section steels 11 and 21 shown in Embodiments 2 and 3 as structural members, since the adhesion between the H-section steels 11 and 21 and concrete or the like is large, a greater proof stress is achieved. It can be set as the wall body which has.

  In addition, although the construction method of the wall body which concerns on this invention is not specifically limited, For example, it can be set as an underground wall as shown to Fig.6 (a), (b). First, the earth retaining wall is built in the ground, the ground on the ground space side is excavated until reaching the earth retaining wall, the earth and sand are removed, and the flanged outer surface of the H-shaped steel with projections faces the wall surface. A plurality of H-shaped steels with protrusions are erected at intervals in the longitudinal direction of the wall to create a steel structure part. After that, by placing concrete or solidified soil in the formwork, the steel structure and the concrete or solidified soil are integrated to construct a wall body. After that, the space between the wall body having the steel structure part in which the H-shaped steel with protrusions is used as a structural member and the earth retaining wall is backfilled to form an underground wall.

Figure using H-section steel 1 with web height H of 588 mm, flange width Wf of 300 mm, web thickness of 12 mm, flange thickness of 20 mm, and concrete 31 with compression strength σc after solidification of 29 (N / mm ² ) The effect of the present invention was verified by a test body for measuring the adhesive force between H-section steel and concrete as shown in FIG.

At that time, an H-shaped steel without protrusions on the inner surface of the flange (referred to as an H-shaped steel without protrusions) was used as the test body 1, and the specimens 2 to 4 were provided with the protrusions 2. The protrusion pitch P, the protrusion height h, and the protrusion width b in the test bodies 2 to 4 are as follows.
Specimen 2: P = 50 mm, P / h = 17, b = 12.5 mm
Specimen 3: P = 100 mm, P / h = 33, b = 12.5 mm
Specimen 4: P = 150 mm, P / h = 50, b = 12.5 mm
In addition, the protrusion 2 of the H-section steel 1 with protrusions used for the test bodies 2, 3 and 4 was welded to the H-section steel using a steel square member as a protrusion member. Further, in the test, a steel jig was used to sandwich and restrain the side concrete surface from both sides.

A load is loaded on each of the obtained specimens in the direction indicated by the arrow in FIG. 7, and the relative displacement amount at that time is detected. The relative displacement amount (mm) is plotted on the horizontal axis, and the adhesion stress τ (N / Mm ² ) and shown in FIG. Bond stress of τ (N / mm ^2), the sum SUM of the flange in the area in contact with the mounting load and the concrete (SUM = (300-12) × 500 × 2 = 288000mm 2
) Divided by. The loading method was a monotonic loading method by punching with displacement control.
In addition, the maximum adhesion stress τ ′ _max in each of the above-described specimens
Table 1 shows the ratio of the maximum adhesion stress τ ′ _max of each test specimen to the maximum adhesion stress τ ′ _max of the test specimen 1, the maximum loading load, and the relative displacement amount at the maximum loading load. In addition, since the allowable value of the relative deviation amount between steel and concrete in the case of a steel / concrete wall is assumed to be about 5 mm, comparison was made within that range.

As can be seen from Table 1, in the test bodies 2 to 4 provided with the protrusions, the maximum adhesion stress degree is remarkably larger than that of the test body 1 without the protrusions.
However, the required adhesion strength for the wall structure is 3.0 N / mm ² , but for test body 2 (projection pitch P = 50 mm) and test body 3 (projection pitch P = 100 mm), 3.0 N / mm ² is required. Although greatly exceeding, the maximum adhesion stress degree was less than 3.0 N / mm ^{2 in} the specimen 4 (protrusion pitch P = 150 mm).
From this, it can be seen that it is necessary to satisfy P / h ≦ 40 and P / b ≧ 4, which are the scope of the present invention, in order to ensure the adhesion strength necessary for the wall structure.
That is, by using the H-section steel 1 with a flange inner surface projection having a projection within the scope of the present invention, a wall body having high proof stress and high rigidity can be obtained, and a thinner wall can be obtained.

  In order to examine the adhesion characteristics of the rolling formed protrusions (see FIGS. 11 and 24), the same experiment as in Example 1 was performed. In this example, the present invention example is set as test bodies 5, 9, and 10, a comparative example for verifying the influence of the protrusion pitch, the test body 6, a comparative example for verifying the influence of the protrusion height, A test sample 8 was used as an example of the present invention for verifying the influence of the projection direction. In the test, the side concrete surface was sandwiched and restrained from both sides using a steel jig as in Example 1.

(1) Consideration about the influence of the protrusion pitch P In order to consider the influence of the protrusion pitch P, the degree of adhesion stress (N / mm ² ) and the relative deviation (mm) for the test body 1, the test body 5 and the test body 6 The relationship is shown in FIG.
As can be seen from FIG. 9, the maximum degree of adhesion stress within the relative deviation amount δ = 5 mm greatly exceeds the adhesion strength of 3.0 N / mm ² required for the wall structure in the specimen 5 (projection pitch P = 50 mm). However, in the specimen 6 (projection pitch P = 150 mm), the maximum adhesion stress was less than 3.0 N / mm ² . From this, it can be seen that it is effective to obtain the adhesion strength required for the wall structure in the rolling formed protrusions so that the protrusion pitch is P / h ≦ 40.

(2) Consideration of the effect of the protrusion height h In order to consider the influence of the protrusion pitch, the degree of adhesion stress (N / mm ² ) and the relative deviation (mm) for the test body 1, the test body 5 and the test body 7 ) Is shown in FIG.
As can be seen from FIG. 10, the maximum degree of adhesion stress when the relative displacement δ = 5 mm greatly exceeds the adhesion strength of 3.0 N / mm ² required for the wall structure in the specimen 5 (projection height h = 3 mm). However, in the test body 7 (projection height h = 1.2 mm), the maximum adhesion stress was less than 3.0 N / mm ² .
In addition, as shown in Table 2, the maximum adhesion stress levels of the test body 9 (projection height h = 2 mm) and the test body 10 (projection height h = 2.5 mm) are 3.95 N / mm ² and 4.01 N / respectively. a mm ^2, exceeds the adhesive strength 3.0 N / mm ² required as the wall structure.
From the above results, it is understood that the protrusion height h for obtaining a predetermined adhesion strength is preferably within the range of the present invention (P / h ≦ 40).

(3) Consideration about influence of protrusion direction (curved shape) When a protrusion having a curved shape as shown in FIG. 11 is provided, the case where the concave side becomes a surface for pushing out concrete (FIG. 11 (a), The test body 8) was used, and the case where the convex side was the surface through which concrete was pushed out was taken as the reverse direction (FIG. 11 (b), test body 5).
In order to consider the influence of the protrusion direction (curved shape), FIG. 12 shows the relationship between the degree of adhesion stress (N / mm ² ) and the relative deviation (mm) for the test body 5 and the test body 8.
As can be seen from FIG. 12, the maximum adhesion stress level within the relative displacement δ = 5 mm greatly exceeds the adhesion strength of 3.0 N / mm ² required for the wall structure, and the curvature of the protrusions that push through the concrete. There was no significant difference in adhesion characteristics even when the surface was changed. That is, it can be seen that the protrusion direction (curved shape) does not significantly affect the adhesion characteristics, and the bending direction may be any direction.

  In the case where the protrusions are formed by rolling as in the present embodiment, as shown in FIG. 13, a protrusion may be formed at the boundary between the flange and the web. Then, although the influence on the adhesive force by forming this ledge was verified, it was confirmed that the adhesive force was not lowered by forming the ledge at least.

Using an H-shaped steel having the same cross-sectional dimensions as in Example 1, a protrusion 2 having a protrusion height of 3 mm, a protrusion width of 12.5 mm, and a protrusion length of 50 mm was formed on the inner surface of the flange with a protrusion pitch P = 50 mm. However, the protrusion 2 of the H-section steel 1 with flange inner surface protrusion was disposed by welding attachment as shown in FIG. 1 using a steel square member as a protrusion member.
A simulated wall body was constructed on a rectangular parallelepiped base as shown in FIG. 14 using the above H-shaped steel 1 with flange inner surface projection as a structural member, and a test was performed by loading a repeated load in the direction indicated by the arrow in the figure.

  As a result, as shown in FIG. 15, the simulated wall body using the H-shaped steel with flange inner surface protrusions having the protrusions within the scope of the present invention on the inner surface of the flange has a maximum load with respect to the displacement of the loading point position. The value was 1.3 times or more than the maximum load of the simulated wall body using steel, and it was found that it had high proof stress. In addition, the rigidity of the simulated wall body using the H-section steel with flange inner surface protrusions having the protrusions within the scope of the present invention is 1.3 times the rigidity of the simulated wall body using the H-shaped steel without protrusions. That's it.

It was demonstrated by Examples 1 to 3 that a predetermined adhesion strength was secured with respect to the punching force.
However, since the force acting on the actual wall body is the bending / shearing force, the demonstration of the performance against the punching force alone is not sufficient as the demonstration of the performance as the wall body.
Therefore, in this example, the performance of the steel / concrete wall body with respect to bending / shearing force was confirmed using a full-size test specimen.
FIG. 16 is an explanatory view of the test body of this example, and has a structure in which the H-section steel 1 is arranged in the center and the periphery thereof is surrounded by concrete 31. Protection plates 33 for protecting the concrete 31 are provided at both ends and the axial center of the test body, and the both ends are supported and loaded on the axial center. The specifications of the H-shaped steel were the same as those shown in Example 1, and the specifications of the protrusions (including the manufacturing method and dimensions) and the specifications of the concrete were the same as those of the test body 5 of Example 2.

  The performance to be provided as a steel / concrete wall was calculated by FEM analysis. As an analysis model, the mechanical properties of concrete and H-section steel are modeled by the stress-strain curve (non-linear model) obtained from each element test result, and between concrete and H-section steel. On the boundary surface, the adhesion characteristics were modeled using interface elements based on the punch adhesion test.

As a test, when the specimen shown in FIG. 16 was loaded at the center, the deflection of the loading point was determined. FIG. 17 is a graph showing the test results, in which the horizontal axis indicates the deflection (mm) of the loading point, and the vertical axis indicates the load (kN).
As can be seen from FIG. 17, the experimental results are in good agreement with the calculated values considering the adhesion characteristics, so it is confirmed that the steel / concrete wall has the expected performance against bending and shearing forces. did it.

It is explanatory drawing of the H-section steel 1 with a protrusion which concerns on Embodiment 1 (reference example) , Fig.1 (a) is a schematic plan view, FIG.1 (b) is XX partial sectional drawing. It is explanatory drawing of the H-section steel 11 with a protrusion concerning Embodiment 2 (reference example) , FIG. 2 (a) is a schematic plan view, FIG.2 (b) is a YY partial sectional view. It is a schematic plan view of the H-section steel 21 with a protrusion which concerns on Embodiment 3 of this invention. It is explanatory drawing explaining the wall body which concerns on Embodiment 4 of this invention. It is explanatory drawing explaining the effect of Embodiment 4 of this invention. It is a schematic diagram which shows an example of the construction method of the wall body which concerns on this invention. It is explanatory drawing explaining the adhesive force measurement experiment of the H-shaped steel with a protrusion in an Example, Fig.7 (a) is a side view, FIG.7 (b) is a front view. 6 is a graph showing the effect of the H-shaped steel with protrusions in Example 1. 10 is a graph for explaining the influence of the protrusion pitch in Example 2. It is a graph explaining the influence of the protrusion height in Example 2. FIG. FIG. 10 is an explanatory diagram of the direction of protrusions in Example 2. 6 is a graph for explaining the influence of the direction of a protrusion in Example 2. It is explanatory drawing of the shape of the protrusion in Example 2. FIG. It is a figure which shows the simulation wall body structure in Example 3, Fig.14 (a) is a front view, FIG.14 (b) is a side view, FIG.14 (c) is ZZ sectional drawing. It is a graph which shows the effect of the H section steel with a projection in the simulation wall in Example 3. It is explanatory drawing of the test body apparatus of Example 4. FIG. 10 is a graph for explaining the effect of Example 4; It is explanatory drawing of the cross-sectional shape of the processus | protrusion which concerns on this invention. It is explanatory drawing for demonstrating the basis of the numerical limitation of this invention. It is explanatory drawing explaining a shear fracture | rupture. It is explanatory drawing for demonstrating the basis of the numerical limitation of this invention. It is explanatory drawing for demonstrating the basis of the numerical limitation of this invention. It is explanatory drawing of the protrusion shape of this invention. It is explanatory drawing explaining the protrusion shape and arrangement | positioning of this invention. It is explanatory drawing of the wall body structure which concerns on this invention. It is explanatory drawing for demonstrating the basis of the numerical limitation of this invention. It is a cross-sectional view which shows the structure of the conventional SRC wall body.

Explanation of symbols

1, 11, 21 H-shaped steel with protrusions 2 Protruding members 3, 31, 32 Concrete (solidified soil)
4 Horizontal bars 5 Main bars
h, h1, h2 Protrusion height b Protrusion width of rectangular cross section protrusion
b1 Lower side protrusion width in protrusion section
b2 Upper side protrusion width in protrusion cross section
L, L1, L2, L3 Projection length: Distance from projection root to projection tip P Projection pitch A1, A2, A3, A10 Wall thickness B1, B2, B3, B10 Distance from flange outer surface to wall surface H Web height Wf Flange width

Claims (6)

An H-shaped steel having a plurality of protrusions on the inner surface side of the flange, and a lower side width b ₁ and an upper side width b ₂ of the protrusions in a cross section perpendicular to the H-shaped steel surface on which the protrusions are formed and parallel to the web surface _The protrusion height h, the protrusion pitch P, and the protrusion length L in the flange width direction satisfy the following formula, and the protrusion is formed in contact with a corner portion formed by the flange and the web. A featured steel.
2 mm ≦ h ≦ 50 mm, 4b ₁ ≦ P ≦ 40 h , b ₁ / b ₂ ≧ 1, and L ≧ Wf / 6
However, Wf is a flange width. The shape steel according to claim 1, wherein the adhesion reinforcing means is provided on the web surface. The shape steel according to claim ₁ , wherein h ≦ b ₁ when the lower side width of the protrusion is b ₁ . The shape steel according to any one of claims 1 to 3 , wherein the protrusions are provided on the inner surface of the flange and the web surface, and the protrusions provided on both are integrated. A wall body using the structural steel according to any one of claims 1 to 4 as a structural member, and after excavating the ground and removing earth and sand, the outer surface of the flange is directed to the wall surface, and the web surfaces are mutually connected. A wall body characterized in that a plurality of the H-shaped steel bars are erected in the longitudinal direction of the wall body and faced with concrete . 6. The wall body according to claim 5, wherein adjacent shape steels are connected by a connecting member.

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