JPH10252143A - Steel framed column leg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel framed column leg which is excellent in dynamics and execution without making size of foundation concrete and the number of anchor bolts excessive. SOLUTION: With regard to a steel framed column leg, the lower end of a steel framed column is fixed on foundation concrete 7 by anchor bolts buried in the foundation concrete 7. The anchor bolt is composed of a steel wire or a steel rod 2 inserted in sheath pipes 1, 1, and the steel wire or the steel rod 2 is composed of a PC steel wire or a PC steel rod. The shape of the anchor bolt is U-shape, and substantially the whole is buried and fixed in the foundation concrete 7 so that both the ends provided with the screw part are protruded from the surface of the foundation concrete 7. A fixing metal 4 and a column leg metal 6 joined to the lower end of the steel framed column are fixed on the anchor bolt by tightening a nut 5 on the screw part after prestressed force is introduced on the anchor bolt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel column base in which a steel column of a steel structure is fixed to a foundation concrete through a column base metal.

[0002]

2. Description of the Related Art Conventionally, according to FIG. 3, a lower end of a steel column 18 is joined to a column base hardware 16 by welding, and the column base metal 16 is attached to an anchor bolt 11 in a foundation concrete 17 by a nut 1.
5, the steel column 18 was fixed in the foundation concrete 17.

In this case, since a lateral force and a couple force are applied to the steel column, a pull-out force and a lateral force are applied to the anchor bolts in the foundation concrete via the column base hardware. In the conventional method in which the pull-out force and the lateral force are absorbed only by the axial tension and the compressive force of the anchor bolt, the number of the anchor bolts is large and the required cross-sectional area is large. If the required number of anchor bolts increases, construction becomes difficult. In addition, the size of the fixing hardware also increases, which impairs the appearance of the building.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a steel column base which is more mechanically superior and has good workability without excessively increasing the dimensions of the foundation concrete and the number of anchor bolts.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a steel column base having a lower end fixed to a base concrete by anchor bolts embedded in the base concrete (7). Wherein (a) the anchor bolt comprises a sheath tube (1) and a steel wire or steel rod (2) passed through the sheath tube (1), and (b) a steel wire or steel bar (2)
(C) the shape of the anchor bolt is U-shaped and substantially the entire base is formed so that both ends provided with the threaded portions protrude from the surface of the base concrete (7). (D) A fixing metal (4) and a column base metal (6) joined to the lower end of the steel column (8) are fixed by embedding in the concrete (7). The problem is solved by a steel column base characterized by being fixed to an anchor bolt by tightening a nut (5) to the screw portion after being introduced.

According to the present invention, the anchor bolt has a double structure, the outer member of which is formed by a tubular member so as to be well bonded to the foundation concrete and to have suitable surface characteristics such as durability. The core material is selected mainly for strength, a PC steel wire or a PC steel bar made of a steel wire or a steel bar and pre-stressed is used, and the anchor bolt shape is substantially U-shaped. By embedding the whole body in the foundation concrete and fixing both ends with the threaded parts in the foundation concrete so that it protrudes from the foundation concrete surface, the tension in the axial direction of the anchor bolt, the compressive force, the shear force, etc. That is, by effectively using the strength of the entire anchor bolt, the dimensions of the foundation concrete can be reduced without impairing the appearance of the building, and the number of anchor bolts can be reduced. Small Toe can dynamically excellent fixing property than the conventional method of steel columns is obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a steel column base according to the present invention will be described based on the illustrated embodiment. According to FIG. 1, a U-shaped anchor bolt is used for fixing the lower end of the steel column 8 in the foundation concrete 7. The anchor bolt is a hollow sheath tube 1 and a PC steel wire or a P steel wire passed through the sheath tube 1.
The sheath tube as an outer member is formed so as to have good surface characteristics that are well bonded to the base concrete and has durability, and the core material is prestressed mainly for strength. It has high strength by using a hung steel wire or a steel rod, and the anchor bolt has its threaded end substantially protruding from the surface of the foundation concrete 7 by a predetermined length. Is buried and fixed in the foundation concrete 7.

In order to install the steel column 8, a mortar 3 is first placed around a hole (not shown) in the steel column 8 of the foundation concrete 7 to be buried. When the steel column 8 is installed, the anchor bolt is passed through the hole provided in the mortar 3, through the hole of the fixing hardware 4 fixed to the lower end of the steel column 8, and through the hole of the column base metal 6. . The lower end of the steel column 8 is fixed to the fixing hardware 4, and the fixing metal 4 is fixed to the column base metal 6. After the prestressing force is introduced into the anchor bolt, steel columns 8
The fixing metal 4 and the column base metal 6 fixed to the lower end of the steel column are fitted through the holes, and the lower end of the steel column 8 is inserted into the hole (not shown) in the foundation concrete 7 through the column base metal 6. By tightening the nuts 5 on the threaded portions at both ends of the anchor bolt, the steel column 8 can be fixed to the anchor bolt and installed on the foundation concrete 7.

The steel column pedestal assembled as described above is under the following mechanical conditions. Flexural Yield Strength This expression of anchor bolts to counter couple exerted on steel columns _{8, My = n t · b} a · bσ y (d t + d c) + Nd c N; vertical load by steel columns n _t; Jikudan area of the anchor bolt b _a;; tensile side anchor bolt number, anchor bolt number a _1, which is arranged on one side of the cross section neutral axis of the column Jikudan area of the anchor bolt bσ _y; yield of the anchor bolt strength d _t The distance from the center of the column at the point of application of the tensile force T to the center of the column d _c ; the distance from the center of the column at the point of application of the resultant force of compression C M; bending moment My; bending yield strength C; The resultant force of the bolt's tensile force is normally SS400 (conventional unit SS4
1) is used as, for example yield strength in the case of 13φ as about 1.2 safety _{factor, T = bσ y · a 1} =
2400 × 1.327 × 0.85 = 2977 kg / piece.

[0010] SBPD130 / 145 used in the present invention
For profiled PC steel bars, with the same diameter as the above case, as the order of about 1.2 safety factor _{Similarly, T = bσ y · a 1} = 13000 × 1.327 × 0.85
= 14663kg / piece, about 1/5 of the number of anchor bolts required conventionally
And the required number of anchor volts is reduced.

Further, the anchor bolt is formed in a U-shape, most of which is buried in the foundation concrete, and both ends provided with the threaded portions are projected from the surface of the foundation concrete. By using one anchor bolt to fix the steel column in two places by tightening the nut through metal, the tension, compression force, shear force, etc. of the anchor bolt, that is, the entire anchor bolt, The strength can be used effectively, thereby reducing the required number of anchor bolts and improving anchorage of the anchor bolts.

The maximum shear strength with respect to a lateral force acting on a steel column base is expressed by the following equation. _{Q max = n e · ba ·} bσ y / 3 1/2 + 0.4C Q max; maximum shear strength n _e; effective number of anchor bolt [= n-T / ba · bσ
_y ] n; total number of anchor bolts T; tensile force applied to anchor bolts ba; cross-sectional area of anchor bolts b? _y ; yield point of anchor bolts C; compressive force In the case of, the compressive force C increases, so that the number of anchor bolts has at least a considerable maximum shear strength.

However, the columns on the tension side during an earthquake of a building can hardly be expected to have a shear strength due to a compressive force of 0.4C.
Therefore, in the present invention, the anchor bolt is made of PC steel wire or P steel wire.
By using a C steel rod, a prestressing force can be introduced into the anchor bolt, and a shear strength of 0.4 C can be added to the column that becomes the tensile side during an earthquake.

[0014]

According to the present invention, the anchor bolt has a double structure, a prestressing force is introduced by using a PC steel wire or a PC steel rod as a core material, and the anchor bolt is formed into a U-shape. This allows both ends to be used for fixing the steel column, thus making effective use of the strength of the entire anchor bolt, and thereby the tensile force and compression acting on the steel column by the entire anchor bolt embedded in the foundation concrete. Since the force is absorbed, there is no need to make the dimensions of the foundation concrete excessive, and it is not necessary to make the number of anchor bolts excessive. This makes it possible to reduce the size of the building without deteriorating the aesthetics of the building, and to secure fixing performance that is mechanically superior to the conventional method.

[Brief description of the drawings]

FIG. 1 is a view showing a steel column base according to the present invention, and FIG.
Is a front view thereof, and (b) is a top view thereof excluding a column base hardware.

FIG. 2 is a diagram showing a mechanical situation in a steel column base according to the present invention.

FIG. 3 is a diagram showing a steel column base structure using anchor bolts according to the related art.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Sheath pipe 2 PC steel wire or PC steel rod 3 Laying mortar 4 Fixing hardware 5 Nut 6 Column base metal 7 Base concrete 8 Steel frame

Claims (2)

[Claims] 1. A steel column base in which the lower end of a steel column (8) is fixed on the basic concrete by anchor bolts buried in the basic concrete (7), (a) the anchor bolt is a sheath tube (1) And (b) the steel wire or rod (2) comprises a PC steel wire or rod and (c) a steel wire or rod (2) passed through a sheath tube (1).
The shape of the anchor bolt is U-shaped, and substantially the entirety of the anchor bolt is buried and fixed in the foundation concrete (7) so that both ends having the threaded portions protrude from the surface of the foundation concrete (7). And (d) anchoring hardware (4) and column base hardware (6) joined to the lower end of the steel column (8).
A steel column base fixed to the anchor bolt by tightening a nut (5) to the screw portion after a prestressing force is introduced into the anchor bolt. 2. Anchor bolts are used as foundation concrete (7).
The steel column base according to claim 1, wherein the steel column base is buried adjacent to an inner reinforcing bar.