JPH04277224A - Exposed column base - Google Patents

Abstract

PURPOSE:To provide a joint area of a column to a base beam in a compact structure, with good economy and a high degree of securing. CONSTITUTION:A protion of a steel column A near the base is filled with concrete 3. As the steel pipe of the steel column A, a steel pipe 1 provided with rib-like inside projections 2 formed by roll molding is used. A plurality of deformed steel rods 4 are placed in an area from the filling concrete 3 to a base beam B. A part or the whole of bending moment Mo acting on the steel column A is transmitted from the steel pipe 1 with internal projections to the filling concrete 3, further through the deformed reinforcement rods 4 to the base beam B. According to the above processes it becomes possible to make each base plate 5 in a compact size and to drastically reduce axial force exevted on anchor bolts 6.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to exposed type column bases of steel pipe columns and open cross-section steel columns made of H-shaped steel or steel assembled in a cross shape. Used to anchor to the foundation.

0002

[Prior Art] As a conventional exposed type column base, for example, FIG.
4, a plurality of anchor bolts 16 assembled using a fixing plate 17 etc. which also serves as a positioning device are embedded in the foundation beam B of the reinforced concrete structure, and the foundation beam B
After the concrete has hardened, the base plate 15 welded to the end of the steel pipe column A is fastened to the anchor bolt 16, and grout 18 is injected into the gap between the base plate 15 and the upper end of the foundation beam B. be.

[0003] In addition, there is a method called a high base construction method, in which a specially shaped heavy base plate is welded to the lower end of a steel pipe column and the base plate is fastened to anchor bolts supported by a steel frame embedded in a foundation beam. There is.

0004

[Problems to be Solved by the Invention] In the conventional exposed column base, the bending moment M acting on the lower end of the steel pipe column A causes bending deformation of the base plate 15 and elongation deformation of the anchor bolt 16, as shown in FIG. Therefore, the degree of fixation of the lower end of column A is reduced.

In order to achieve economical design of buildings, it is necessary to increase the degree of fixation of column bases, but in order to achieve this with the conventional technology, a heavy and long base plate that suppresses bending deformation of the base plate 15 is required. Is required. Furthermore, in order to suppress the elongation and deformation of the anchor bolts 16, a large number of anchor bolts are required. Conventionally, these problems have hindered economic efficiency in the design of exposed column bases.

[0006] In order to solve these problems, it is an object of the present invention to provide an exposed column base with a compact cross section and a high degree of fixation.

[0007]

[Means for Solving the Problems] In the first type of exposed column base of the present application, concrete is filled near the column base of a steel pipe column, one end is placed in the filled concrete of the steel pipe column, and the other end is placed in the foundation. Multiple deformed reinforcing bars are arranged inside reinforced concrete members such as beams.

[0008] Furthermore, for at least the section of the steel pipe column filled with the concrete, a steel pipe with internal protrusions having rib-like protrusions formed by rolling on the inner surface is used,
Ensures adhesion to concrete.

[0009] In this way, rolled protrusions etc. that have excellent adhesion to concrete are formed near the base of the steel pipe column,
In addition, by filling the steel pipe column with concrete, part or all of the bending moment acting on the steel pipe column can be transmitted from the steel pipe to the filling concrete inside. moreover,
The stress transmitted to the filled concrete is transmitted to the reinforced concrete member to which the steel pipe column is anchored, via deformed reinforcing bars arranged within the filled concrete.

[0010] Also, instead of a steel pipe with internal protrusions having rib-like protrusions on part or all of the inner surface, a steel plate with protrusions is bonded to the inner surface of a normal square or circular cross-section steel pipe by welding or the like. It's okay.

[0011] In the second type of exposed type column base of the present application, H
Fill concrete near the column base of an open cross-section steel column made of shaped steel or steel assembled in a cross shape, and then place one end inside the filled concrete of the steel column and the other end inside a reinforced concrete member such as a foundation beam. Multiple anchored deformed reinforcing bars are arranged.

[0012] Further, rib-shaped protrusions are provided on at least the portions of the web of the steel column, the inner surface of the flange, etc. that come into contact with the filling concrete, to ensure adhesion to the concrete.

[0013] In this way, by forming rolled protrusions etc. that have excellent adhesion with concrete near the base of the steel column and filling them with concrete, part or all of the bending moment acting on the steel column can be reduced. All can be transferred from the steel column to the internal filling concrete. Furthermore, the stress transmitted to the filled concrete is transmitted to the reinforced concrete member to which the steel column is anchored, via deformed reinforcing bars arranged within the filled concrete.

[0014]

[Operation] The operation of the present invention will be explained below based on FIG. 1 (when the column A is a steel pipe column).

First, due to the bending moment M0 acting on the column base of the steel pipe column A, a tensile force Tp and a compressive force Cp in the axial direction act on the cross section of the steel pipe 1.

The tensile force Tp and compressive force Cp are transmitted to the filling concrete 3 by the concrete adhesion force τs of the protrusion 2 rolled on the inner surface of the steel pipe 1.

The stress in the filled concrete 3 generated by the tensile force Tp is transmitted to the foundation beam B of the reinforced concrete structure by the tensile force σt of the deformed reinforcing bars 4 fixed in the filled concrete 3.

On the other hand, the stress in the filled concrete 3 generated by the compressive force Cp becomes a concrete compressive force fc, which is directly transmitted to the foundation beam B.

From the above, part or all of the bending moment M0 acting on the column base is transmitted by the concrete 3 filled in the steel pipe 1 and the deformed reinforcing bars 4, and the shaft acting on the anchor bolt 6, which is necessary in the prior art, is Directional tensile force T
1 can be significantly reduced.

[0020]

[Embodiment] Next, the illustrated embodiment will be explained.

FIGS. 2 and 3 show an example of the first type (in the case where the column A is a steel pipe column), in which substantially all the stress generated in the steel pipe column A is caused by the steel pipe 1 with internal protrusions. This is an example in which the heat is transmitted from a rolled protrusion 2 to a filling concrete 3. In addition, the reinforcing bars in the foundation beam B are omitted in the figure.

In this embodiment, a steel pipe column A is installed at a predetermined position on the upper surface of the foundation beam B, and concrete is poured with a plurality of deformed reinforcing bars 4 arranged from the base of the steel pipe column A into the foundation beam B. It is set up. In this way, the upper end of the deformed reinforcing bar 4 is embedded in the filling concrete 3 in the steel pipe 1 with internal projections used for the steel pipe column A, and the lower end of the bent deformed reinforcing bar 4 is embedded in the foundation beam B. become. In this embodiment, the base plate and anchor bolt at the lower end of the steel pipe column A are omitted because substantially all of the stress generated in the steel pipe column A is transmitted to the filling concrete 3.

FIGS. 4 and 5 show another example in which a part of the stress generated in the steel pipe column A is transmitted to the filling concrete 3 through the protrusion 2 of the steel pipe 1 with internal protrusions. .

In this embodiment, a base plate 5 is welded to the lower end of the steel pipe column A, and is fixed to the foundation beam B by a plurality of anchor bolts 6 whose lower ends are fixed to the fixing plate 7. However, since a part of the stress generated in the steel pipe column A is directly transmitted to the filling concrete 3 from the projection 2 of the steel pipe 1 with internal projections, the base plate 5 and the anchor bolt 6 can be made more compact.

In the embodiments shown in FIGS. 6 and 7, a steel plate 9 with protrusions on which protrusions 10 are formed by rolling is welded to the inner surface of the column base of an ordinary square steel pipe 8, instead of a steel pipe with inner protrusions. .

The above is an example in which a square cross-section steel pipe is used, but the same applies to a circular cross-section steel pipe.

FIGS. 8 and 9 show an example of the second type (in the case where the column A is a steel column with an open cross section), in which a protrusion-equipped H-shaped steel 1' having a rolled protrusion 2 is used. This shows an example. In addition, the reinforcing bars in the foundation beam B are omitted in the figure.

In this embodiment, a steel column A is installed at a predetermined position on the upper surface of the foundation beam B, and concrete is poured with a plurality of deformed reinforcing bars 4 arranged from the base of the steel column A to the inside of the foundation beam B. It is set up. In this way, the upper end of the deformed reinforcing bar 4 is embedded in the concrete 3 filled between the web 1a' and the flange 1b' of the H-shaped steel 1' with projections used for the steel column A, and the deformed reinforcing bar 4 is bent. 4 will be embedded in the foundation beam B. In this embodiment, a base plate 5 is welded to the lower end of a protruded H-shaped steel 1' serving as a steel column A, and is fixed with anchor bolts 6.

FIGS. 10 and 11 show another example,
This shows an example in which a cross-shaped steel material 1'' with projections, which is made by assembling a cross-shaped web 1a'' and four flanges 1b'' by welding or the like, is used as the steel column A.In this example, Protrusions 2 are formed by rolling on both sides of the cross-shaped web 1a'' and on the inner surface of the flange 1b''.

In this embodiment as well, the base plate 5 is welded to the lower end of the steel column A, and is fixed to the foundation beam B by a plurality of anchor bolts 6 whose lower ends are fixed to the fixing plate 7.

In both of the above embodiments, a part of the stress generated in the steel column A is directly transmitted to the filling concrete 3 from the protrusion 2 of the H-beam 1' or the cruciform steel 1'' with the protrusion. 5 and the anchor bolt 6 can be made more compact.

The embodiment shown in FIGS. 12 and 13 is a steel plate 9 with protrusions in which protrusions 10 are formed by rolling on both sides of the web 8a' and the inner surface of the flange 8b' for the column base of a normal H-shaped steel 8'. are welded to form an H-beam with protrusions.

[0033]

[Effects of the invention] ■ Since the stress of the steel pipes generated at the column base can be transmitted to the foundation beam through the filled concrete, the tensile force generated on the anchor bolts can be reduced, making it possible to make the base plate more compact or omit them. It becomes possible.

[0034] Therefore, the entire exposed column base can be made more compact, which is economical.

[0035] Further, by utilizing the adhesion of the protrusions to concrete by rolling, etc., it is possible to provide a column base with high rotational rigidity and yield strength.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view for explaining the operation of the present invention.

FIG. 2 is a vertical sectional view showing an embodiment of the first type of invention.

FIG. 3 is a horizontal sectional view corresponding to FIG. 2;

FIG. 4 is a vertical sectional view showing another embodiment of the first type of invention.

FIG. 5 is a horizontal sectional view corresponding to FIG. 4;

FIG. 6 is a vertical sectional view of a steel pipe column base in still another embodiment of the first type of invention.

FIG. 7 is a horizontal sectional view corresponding to FIG. 6;

FIG. 8 is a vertical sectional view showing an embodiment of the second type of invention.

FIG. 9 is a horizontal cross-sectional view corresponding to FIG. 8;

FIG. 10 is a vertical sectional view showing another embodiment of the second type of invention.

FIG. 11 is a horizontal sectional view corresponding to FIG. 10;

FIG. 12 is a vertical sectional view of a steel column base in still another embodiment of the second type of invention.

FIG. 13 is a horizontal cross-sectional view corresponding to FIG. 12;

FIG. 14 is a vertical sectional view showing a conventional example.

FIG. 15 is an explanatory diagram for explaining problems in the conventional example.

[Explanation of symbols]

A...Column, B...Foundation beam, 1...Steel pipe with internal protrusion, 2...Protrusion, 3...Concrete, 4
... Deformed reinforcing bar, 5... Base plate, 6... Anchor bolt, 7... Fixing plate, 8... Square steel pipe, 9... Steel plate with projections, 10...
Protrusion 1'...H-shaped steel with protrusion, 1"...Cross-shaped steel with protrusion, 8'...
H-shaped steel

Claims (4)

[Claims] Claim 1: In an exposed type column base of a steel pipe column in which a steel pipe column is fixed on a reinforced concrete member constituting a foundation, the vicinity of the column base of the steel pipe column is filled with concrete, and the steel pipe column A steel pipe with internal projections is used at least in the section filled with the concrete, and a plurality of irregularly shaped steel pipes are fixed at one end in the filling concrete near the base of the steel pipe column and at the other end in the reinforced concrete member. Exposed column base characterized by reinforced reinforcement. 2. The exposed type column pedestal according to claim 1, wherein the steel pipe with internal projections is a rolled steel pipe having rib-shaped projections on its inner surface. 3. The exposed column base according to claim 1,
An exposed type column base characterized in that instead of using a steel pipe with inner surface projections, a steel plate with projections is joined to the inner surface of the steel pipe at least in the section filled with concrete. 4. In an exposed type column base of a steel column in which a steel column with an open cross section is fixed on a reinforced concrete member constituting a foundation, the vicinity of the column base of the steel column is filled with concrete, A rib-shaped protrusion is provided on at least a portion of the steel column that contacts the concrete, and one end of the steel column is fixed in the filling concrete near the base of the steel column, and the other end is fixed in the reinforced concrete member. Exposed column base characterized by the fact that it is reinforced with deformed reinforcing bars.