JPH1025801A - Anchoring structure of steel column base - Google Patents

Abstract

(57) [Problem] To provide an anchoring structure for a steel column base in which the shear strength of the steel column base is large and the installation work is easy. SOLUTION: A steel column base formed by integrally joining a column base metal to a lower end of a steel column is attached to an upper end of an anchor bolt embedded in basic concrete through a bolt hole provided in the column base metal. In the anchoring structure of the steel column base that is inserted and fixed on the foundation concrete via a nut screwed to the upper end of the anchor bolt, an opening is provided on a side surface of the column base metal and is connected to the bolt hole. A grout injection hole is provided, and grout is filled from the grout injection hole into the gap between the anchor bolt and the bolt hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing structure of a steel column base for fixing a steel column base constituting a building on foundation concrete.

[0002]

2. Description of the Related Art FIGS. 2 and 3 are a longitudinal sectional view and a plan view, respectively, showing a main part of a conventional steel column base anchoring structure. 2 and 3, reference numeral 5 denotes an anchor bolt, which is made of, for example, a steel bar, is provided with a screw at an upper end portion, and is positioned and embedded in the foundation concrete 9.

Next, after the foundation concrete 9 has been cured and solidified, the column base metal 11 is inserted through the central mortar 10.
Is placed on the lower end of the steel column 12, the steel column base 13 is placed and positioned, and then the non-shrink mortar 14 is filled between the column base metal 11 and the foundation concrete 9.

A washer 1 is provided at the upper end of the anchor bolt 5.
The steel column base 13 is fixed on the foundation concrete 9 by mounting the nut 5 and the nut 16 and tightening the nut 16.

[0005]

SUMMARY OF THE INVENTION A steel column base 1 having the above structure.
When a bending moment MH as shown in FIG. 2 acts on 3, a tensile force QF acts on one anchor bolt 5. What opposes the tensile force QF is the adhesive force between the anchor bolt 5 and the foundation concrete 9 and the fixing force of a fixing plate (not shown) fixed to the lower end of the anchor bolt 5. Of these, even if an attempt is made to increase the adhesive force between the anchor bolt 5 and the foundation concrete 9, the anchor bolt 5 is usually formed of round steel and has a smooth surface, so that the adhesive force is unstable and greatly increases. It is difficult to let.

Accordingly, there is a tendency that the embedding depth of the anchor bolt 5 is increased. However, the adhesion between the anchor bolt 5 and the foundation concrete 9 is broken down with time from the upper end portion and proceeds downward, so that the anchor bolt 5 advances downward. In this case, it is difficult to set the above-mentioned adhesive force, and as a result, there is a problem that the elongation of the anchor bolt 5 becomes large and the degree of fixation of the steel column base 13 decreases.

Next, when a horizontal load QH as shown in FIG. 2 is applied to the steel column base 13, the frictional force between the column base metal 11 and the foundation concrete 9 and the shear stress of the anchor bolt 5 cooperate. To compete. In this case, a bolt hole (not shown) provided in the column base metal fitting 11 is formed to have a diameter larger than that of the anchor bolt 5 and is loosely fitted to the anchor bolt 5, so that the horizontal load QH is not applied. There is a problem in that the shear stress to be opposed cannot be sufficiently exerted, and the horizontal proof strength of the steel column base 13 is insufficient.

Further, the nut 16 screwed to the upper end of the anchor bolt 5 must be securely fastened in order to secure a frictional force between the column base metal 11 and the foundation concrete 9. Usually, a double nut (not shown) is screwed on the upper part to prevent loosening. However, screwing the nut 16 to the anchor bolt 5 and further screwing the double nut has a problem that the installation work of the steel column base 13 at the construction site becomes complicated.

The present invention solves the above-mentioned problems in the prior art, can increase the shear strength of the steel column base, prevents the anchor bolt from being loosened, and facilitates the installation work of the steel column base. It is an object to provide an anchoring structure for a certain steel column base.

[0010]

In order to solve the above-mentioned problems, according to the present invention, a steel column base, which is formed by integrally joining a column base metal to a lower end of a steel column, is provided on the column base metal. Anchoring structure of a steel column base that is inserted through an upper end of an anchor bolt buried in foundation concrete through a bolt hole that has been set and is fixed on the foundation concrete via a nut that is screwed into the upper end of the anchor bolt. A technical means of providing a grout injection hole having an opening on the side surface of the column base metal and communicating with the bolt hole, and filling grout into the gap between the anchor bolt and the bolt hole from the grout injection hole is adopted. did.

In the present invention, the opening of the grout injection hole can be formed in a tapered shape. When grout is injected, a grout injection pump is used. With the above configuration, the discharge port of the grout injection pump can be easily engaged with the opening of the injection hole.

In the above invention, the anchor bolt can be formed of a deformed bar. As the deformed steel bar, rebars called screw joints, bamboo joints, and staple joints can be used.
It is preferable because a nut can be screwed directly to the upper end.

[0013]

FIG. 1 is an enlarged longitudinal sectional view of a main part showing the vicinity of an upper end portion of an anchor bolt according to an embodiment of the present invention, and the same parts are denoted by the same reference numerals as those in FIGS. 2 and 3. . In FIG. 1, reference numeral 21 denotes a bolt hole, which is provided at, for example, four corners of the column base hardware 11. Next, reference numeral 22 denotes a grout injection hole, which has an opening 23 on a side surface of the column base metal 11 and is formed so as to communicate with the bolt hole 21.

Next, reference numeral 17 denotes an anchor bolt formed of, for example, SD490 deformed steel bar (threaded bar).
It is buried in the foundation concrete 9 and has a washer 1 at its upper end.
The nut 16 is screwed through the 5 and a steel column (not shown)
Then, the column base metal fitting 11 joined is fixed.

After fixing the column base hardware 11 as described above,
Grout is injected and filled from the grout injection hole 22 into the gap between the anchor bolt 17 and the bolt hole 21 by a grout injection pump (not shown). A part of the grout injected also enters the nut 16 from the washer 15 and the nut 1
Since the gas is blown out from the upper part of 6, the filling and filling of the grout can be confirmed.

With the above configuration, a steel column base (not shown)
When the bending moment acts on the anchor bolt 17 and the tensile force QF acts on the anchor bolt 17,
Since 7 is formed by the threaded bar, it resists the tensile force QF by the adhesive force with the base concrete 9, so that the steel column base (see reference numeral 13 in FIG. 2) can be fixed. As a result, the embedding depth of the anchor bolt 17 can be made smaller than that of the conventional one shown in FIG.

Further, a bolt hole 2 provided in the column base hardware 11 is provided.
By grouting and filling grout 1, anchor bolt 17 and column base metal 11 can be integrated, horizontal load QH acting on column base metal 11 can be countered, and steel column base 13 (FIG. 2), the shear stress of the anchor bolt 17 can be sufficiently exerted.

Further, the nut 16 can be firmly fixed by the grout injection and filling, so that the screwing of the double nut is not required, and the installation work at the construction site becomes easy.

In the above embodiment of the present invention, an example in which the anchor bolt 17 is formed by a threaded bar is described. Alternatively, a bamboo bar or a barbed bar may be used as the deformed bar. However, when these deformed steel bars are used, screw members are integrally joined to their ends by joining means such as, for example, friction welding, and are formed so that they can be screwed with a nut.

The present invention can be applied not only to a steel column made of a square steel pipe but also to a steel column made of a round steel pipe, a polygonal steel pipe, and an H-shaped steel. Naturally, geometric shapes other than shapes can be selected.

Further, the column base metal in the present invention is preferably formed by casting means or forging means, but may be formed by a thick steel plate.

[0022]

Since the present invention has the above-described configuration and operation, the following effects can be obtained.

(1) By forming the anchor bolts with the deformed steel bars, the adhesion to the foundation concrete is increased, the rotational rigidity is improved, and a higher-performance anchoring structure for the steel column base is obtained.

(2) The embedding depth can be greatly reduced and the proof stress can be improved as compared with the conventional method using a round steel anchor bolt. (3) Since grout is injected and filled into the bolt holes of the column base hardware, the strength against the horizontal load is increased, and the screwing of the double nut is not required, thereby facilitating the installation work.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view of a main part showing the vicinity of an upper end portion of an anchor bolt according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part showing an example of a conventional anchoring structure for a steel column base.

FIG. 3 is a partial cross-sectional plan view showing an example of a conventional anchoring structure for a steel column base.

[Explanation of symbols]

 11 Column base hardware 12 Steel column 17 Anchor bolt 22 Grout injection hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Kitano 1-9-1 Kitahama-ku, Wakamatsu-ku, Kitakyushu-shi, Fukuoka Prefecture Inside the Wakamatsu Plant of Hitachi Metals Co., Ltd. 9-1 Hitachi Metals Co., Ltd. Wakamatsu Plant (72) Inventor Hidenori Tanaka 4-2-2 Toyo 2-chome, Koto-ku, Tokyo (72) Inventor Kazuyuki Noguchi 2-chome Toyo, Koto-ku, Tokyo No.4-2 Hitachi Machinery Co., Ltd. (72) Kuniaki Sato 24-21 Yaesaki-cho, Hiratsuka-shi, Kanagawa

Claims (3)

[Claims] An upper end of an anchor bolt buried in foundation concrete through a bolt hole provided in said column base metal, wherein the steel column base is formed by integrally joining a column base metal to the lower end of the steel column. In the anchoring structure of the steel column base fixed on the foundation concrete through a nut screwed into the upper end of the anchor bolt, the column base has an opening on the side surface and communicates with the bolt hole. An anchoring structure for a steel column base, characterized in that a grout injection hole is provided in the hole, and grout is filled into the gap between the anchor bolt and the bolt hole from the grout injection hole. 2. An anchoring structure for a steel column base according to claim 1, wherein the opening of the grout injection hole is formed in a tapered shape. 3. The anchoring structure for a steel column base according to claim 1, wherein the anchor bolt is formed of a deformed steel bar.