JPH0662009U - Steel column base hardware - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a pedestal metal fitting that can be used for a column pedestal of a steel frame structure or a steel frame reinforced concrete structure and can always secure a constant and stable shear resistance. [Structure] A bottom portion of a bottom plate of a pillar pedestal is provided with a quadrangular cylindrical bottom side projection, and a mortar inlet and a mortar outlet are further provided on the bottom plate. Due to the filling of the mortar, the bottom surface of the bottom plate and the bottom-side protruding portion are completely adhered to the basic concrete. Therefore, the column base having high rotational rigidity can be secured, and the shearing force transmitted from the column can be reliably transmitted to the foundation concrete via the projecting portion of the column base metal member. This pillar pedestal is manufactured by casting, forging, assembling steel materials, or the like.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a steel column leg metal fitting used for a steel frame structure or a steel frame reinforced concrete structure.

[0002]

[Prior art]

 In the conventional steel column base shown in FIGS. 4 (a) and 4 (b), there are two methods for securing the resistance against the shearing force acting on the column base. The first method is, as shown in FIG. 4 (a), the basic concrete (hereinafter simply referred to as concrete, the cross section of each drawing is generated by the axial force N of the column 3 and the bending moment M generated in the column base). (Hatching is omitted.) The method is to secure the compression reaction force Nc of 5 with the frictional force μNc between the compression reaction force Nc and the bottom of the column base metal 1.

In the second method, in addition to the friction effect, as shown in FIG. 4 (b), mortar 4 or the like is injected into the gap between the anchor bolt hole of the column base metal fitting 1 and the anchor bolt 2, The shearing force Q transmitted from the 3 side is transmitted to the anchor bolt 2 through the column base metal 1, the mortar 4 injected into the gap between the anchor bolt hole of the column base metal 1 and the anchor bolt 2, etc. The bolt 2 ensures the shear resistance.

[0004]

[Problems to be solved by the device]

 However, each of these methods has a problem that it is not possible to secure a large shear resistance force that can resist the shear force acting on the column base depending on the building conditions.

That is, in the method of securing the shear resistance force by the frictional force μNc between the compression reaction force Nc of the concrete 5 of the column base portion and the bottom face of the column base of the first method, as shown in FIG. In the case of the outer pillar 3a on the outer periphery of the building 6 or the pillar 3b of the building 6 having a narrow frontage and a high height as shown in FIG. 5 (b), a large pulling force T is exerted on the pillar pedestal during an earthquake or the like. As shown in FIG. 6, the compression reaction force Nc of the concrete 5 due to the bending moment M acting on the column base portion may be canceled by the axial force N on the extraction side, and the compression reaction force Nc may not be applied to the concrete 5. . In this case, since the compression reaction force Nc of the concrete 5 becomes 0 (zero), the frictional force μNc between the bottom surface 1a of the column base metal 1 and the concrete upper surface 5a cannot be expected, and the shear force Q acting on the column base is Cannot secure resistance.

In the second method, as described above, mortar is injected into the gap between the anchor bolt hole of the column base metal 1 and the anchor bolt 2, and the shearing force Q transmitted from the column side is applied to the column base metal. 1. Further, it is transmitted to the anchor bolt 2 through the mortar 4 and the like in the gap between the anchor bolt hole of the column base metal fitting 1 and the anchor bolt 2, and the anchor bolt 2 secures the shearing resistance. However, as shown in FIG. 7, it is difficult to completely fill the gap between the bolt hole and the anchor bolt 2 with the mortar 4, which is mainly injected from the end of the column base metal fitting 1. In some buildings, it may not be possible to secure the breaking resistance. Therefore, this method has a problem in ensuring the safety of buildings.

In order to solve these conventional problems, the present invention provides a column base of a steel structure or a steel reinforced concrete building that can always ensure a constant and stable shear resistance. It provides hardware.

[0008]

[Means and Examples for Solving the Problems]

 As shown in FIG. 1 or FIG. 2 showing an embodiment, the column base metal fitting 7 of the present invention is provided with a rectangular cylindrical bottom surface side protruding portion 7a on the outer periphery of the bottom surface 7f of the bottom plate 7d fixed to the column 3, and The length D of one side is set to 4.5 times or more the diameter d of the anchor bolt 2, the projection length h is set to 0.45 times or more, and the anchor bolt hole 7e, the mortar inlet 7b, and the mortar outlet are formed on the bottom plate 7d. 7c is a column base metal fitting for a steel column, which is formed by casting, forging, or assembling steel materials.

[0009]

[Operation] The method and procedure for connecting the concrete to the concrete as shown in FIG. 2 by using the steel column pillar metal fitting shown in FIG. 1 will be described. (1) A concrete 5 having a partial flat surface 5a formed by a central mortar 5b and having a central portion of a bottom surface 7f of a column base metal 7 adhered thereto and having an anchor bolt 2 embedded therein is manufactured. (2) After the curing of the concrete 5 is completed, the column base metal fitting 7 attached to the column 3 is installed on the concrete 5, and the column base metal structure 7 is temporarily tightened by the anchor bolt 2. (3) The mortar 4 is press-fitted through the mortar inlet 7b provided in the column base metal 7, and it is confirmed that the mortar 4 is discharged through the mortar outlet 7c, and the filling of the mortar 4 is completed. (4) After curing the mortar 4, the anchor bolts 2 are fully tightened. If the construction is performed by using the column base metal fitting 7 according to the present invention in the above-mentioned procedure, the concrete 5 which is completely adhered to the bottom surface 7f of the column base metal piece 7 and the inner surface of the bottom surface side protruding portion 7a can be secured.

Further, even if the axial force N acts on the pull-out side and the compression reaction force Nc of the concrete 5 is 0 (zero), which is a problem with the first conventional method, it acts on the column base. A resistance force against the shearing force Q can be secured. That is, the shearing force Q transmitted from the column 3 can be transmitted to the concrete 5 via the bottom surface side protrusion 7 a of the column base metal 7.

Further, the problem caused by the second conventional method, that is, the problem that the mortar is not completely filled in the gap between the anchor bolt hole of the column base metal and the shear resistance cannot be secured, can be solved for the same reason. .

The reason why the length D (see FIG. 1) of one side of the bottom projection 7a of the column base metal 7 is set to 4.5 times or more the diameter d of the anchor bolt 2 is as follows. In the conventional column base portion of FIG. 4 (b), the shear resistance force Qc of the column base portion is determined by Equation 1 from the allowable compression force of the mortar 4 filled in the anchor bolt holes.

[0013]

[Equation 1]

However, d: diameter of anchor bolt t: thickness of bottom plate of column pedestal n: number of bolts arranged on compression side of concrete Fc: standard strength of concrete

The theoretical shear resistance Qc of the column base when the column base metal member 7 according to the present invention is used is the smaller value of the formulas 3 and 5.

[0016]

[Equation 2]

The shear resistance is given by equation 3 when equation 2 is taken into consideration. In addition, bearing pressure resistance becomes equation 5 when equation 4 is considered.

[0018]

[Equation 3]

[0019]

[Equation 4]

[0020]

[Equation 5]

However, D: Length of one side of bottom side protrusion of column pedestal metal h: Length of protrusion of bottom side protrusion of column pedestal metal object t ₀ : Thickness of bottom side protrusion of column pedestal metal article

Therefore, in order to secure the shear resistance Qc of the present invention equal to or more than that of the conventional one, the condition of the equation 6 is necessary.

[0023]

[Equation 6]

In consideration of the lower limit condition t≈d, n = 2 in the column base metal fitting 1 of the conventional general formula in the formula 1, the upper formula of the formula 7 is more than that of the formula 6 in the upper formula. As for the inequality, the inequality of the lower equation of the equation 7 is established from the lower equation of the equation 6.

[0025]

[Equation 7]

That is, the length D of one side of the bottom surface side protruding portion 7 a is 4.5 times or more the diameter d of the anchor bolt 2, and the protruding length h is 0.45 times or more the diameter d of the anchor bolt 2. By using the above-described pillar pedestal metal 7 according to the present invention, it is possible to always secure a shear resistance force Qc equal to or higher than the conventional one in the pillar pedestal under any condition.

Furthermore, since the concrete 5 and the bottom surface 7f of the column pedestal 7 are completely adhered by using the column pedestal 7 according to the present invention, as shown in FIG. Rotational rigidity M / θ (M: bending moment generated in the column base, θ: rotation angle of the column base), which is one of the performances, can be increased (contact between concrete 5 and column base metal fitting 7 is rotational rigidity Is a big factor in raising). This leads to a reduction in the size of the members of the upper frame, which makes it possible to reduce the cost of the building.

[0028]

[Effect of device]

 The effects of the present invention mainly include the following two points. (1) In a building under any condition, it is possible to secure a pedestal that always has a constant and even more equal breaking resistance than before. (2) Column base Since the bottom surface of the metal fittings and the concrete are completely adhered, a column base with high rotational rigidity can be secured, and the cost can be reduced by downsizing the upper frame member of the building.

[Brief description of drawings]

1A and 1B are respectively a front view and a bottom view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a column base using the column base metal fitting of the present invention.

FIG. 3 is a sectional view showing a state in which a bending moment acts on the column base of the present invention.

FIG. 4A and FIG. 4B are cross-sectional views showing a conventional column base.

5A and 5B are explanatory views showing a state in which a pulling force is applied to a pillar of a building.

FIG. 6 is a cross-sectional view showing an example of a conventional column base portion.

FIG. 7 is a cross-sectional view showing an example of a conventional column base portion.

[Explanation of symbols]

1 Column Base Metal 1a Bottom 2 Anchor Bolt 3 Column 3a Column 3b Column 4 Mortar 5 Foundation Concrete 5a Foundation Concrete Top 5b Center Mortar 6 Building 7 Column Base Metal 7a Bottom Side Projection 7b Mortar Inlet 7c Mortar Outlet 7e Bottom Plate Anchor bolt hole 7f Bottom surface D Length of one side of protrusion of bottom side of column pedestal d Diameter of anchor bolt h Length of protrusion of bottom side protrusion of column pedestal metal t ₀ Thickness of bottom side protrusion of column pedestal metal M Bending moment N rotation angle of the axial force N _C compression reaction force [mu] N _C frictional force Q shearing force T pullout force θ column base

Claims (1)

[Scope of utility model registration request] 1. A rectangular cylindrical bottom side protrusion is provided on the outer circumference of the bottom plate, and the length of one side of the outline is 4.5 times or more the diameter of the anchor bolt, and the protrusion length is 0.45 times or more. A steel column pedestal, characterized in that the bottom plate is provided with anchor bolt holes, a mortar inlet and a mortar outlet, and is made by casting or forging or assembling steel materials.