JPH07109787A - Concrete-filled square-shaped steel pipe post - Google Patents

Abstract

PURPOSE:To enhance concrete restraint effect, inhibit local buckling and improve toughness by welding a local buckling reinforcing steel plate with an inner side surface of a steel post on both upper and lower ends and a concrete restraint reinforcing steel plate with the outer side surface as well. CONSTITUTION:A flat board-shaped local buckling reinforcing steel plate 2 is welded with the inside of a square-shaped steel plate 1 which comprises a component of a welded plate square-shaped steel pipe post where the steel plate 2 is preliminarily designed to extend in the direction parallel to the axis of the post. The reinforcing steel plate 2-attached steel plate 1 is welded, thereby assembling a square-shaped steel pipe post 3. A flat board-shaped concrete restraint reinforcing plate 4, which extends in the right angle direction with the post axis of the steel pipe post 3, is welded with the outside of both ends of the square-shaped steel pipe post 3. Concrete 5 is filled up in the square- shaped steel pipe post 3 formed in this construction. Even when the concrete restraint reinforcing steel plate 4 is welded with the inside of the steel pipe post while the local buckling reinforcing steel plate is welded with the outside reversely to this construction, similar functions are available.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete-filled rectangular steel pipe column.

[0002]

2. Description of the Related Art Concrete-filled circular steel tubular columns have high strength and rigidity and are used as high-performance structural members. When a concrete-filled steel pipe column receives a compressive load, the steel pipe a
Since the part restrains the protrusion of the concrete b inside from the periphery, the compressive strength of the concrete section rises more than it would be without the steel pipe, while the concrete inside prevents the local buckling of the steel pipe from occurring, The buckling strength of the steel pipe is also higher than in the case without it. (See FIG. 10 (a)) However, when the concrete-filled steel pipe column is not a circular steel pipe column but a rectangular concrete-filled steel pipe column, the pressure applied to the steel pipe wall face by the internal filling concrete causes the steel pipe wall face as shown in a '. The effect of restraining the concrete decreases because it deforms out of the plane. (See FIG. 10B.) If the plate thickness of the concrete-filled rectangular steel tube column A is thin, local buckling easily occurs in the steel tube itself as shown in c, and the toughness is deteriorated. (See FIG. 11) In the figure, d is a beam.

Conventionally, in order to reinforce and stiffen the concrete-filled rectangular steel tubular column, a horizontal rib extending in the direction perpendicular to the column axis over the entire length of the column is provided on the inner surface of the rectangular steel tubular column, and a stiffener is provided in the concrete. Japanese Patent Laid-Open No. 63-27634 discloses a filled rectangular steel tubular column, and a concrete filled rectangular steel tubular column provided with a stiffener and a flat plate-shaped rib extending in the axial direction of the column on the inner surface of the joint of the steel tubular column to the beam. It is proposed in Japanese Patent Publication No. 4-52353.

[0004]

However, in the former case, the horizontal ribs are provided only on the inner surface over the entire length of the steel pipe column, and in the latter case, the vertical ribs are provided only on the inner surface at the beam contact portion of the steel pipe column. Therefore, when the axial force compressive force as a constant load and the horizontal force as a short-term load such as an earthquake are simultaneously applied to the column member, the concrete restraining effect is not sufficient, and there is a difficulty in suppressing local buckling. There was also a problem with the fillability of concrete.

The present invention has been proposed in view of the above-mentioned problems of the prior art. The object of the present invention is to enhance the effect of restraining concrete in a concrete-filled rectangular steel tubular column to suppress local buckling and toughness. There is a point to improve.

[0006]

In order to achieve the above-mentioned object, a concrete-filled rectangular steel tube column according to the present invention is provided at both upper and lower ends of the concrete-filled rectangular steel tube column.
Rectangular buckle steel columns assembled from steel plates for local buckling reinforcement or steel plates for concrete restraint welded to the inner surface in advance to form upper and lower ends of rectangular steel tube columns. It is configured by welding buckling reinforcing steel plates.

[0007]

As described above, the pillar member generates maximum stress at both upper and lower ends of the pillar when the axial compressive pressure and the horizontal force such as an earthquake are simultaneously applied as a constant load. In the case of filled rectangular steel pipe columns, steel plates for local buckling reinforcement or steel plates for concrete restraint are provided on both inner and outer sides of the steel pipe in the plastic hinge zones at the upper and lower ends that produce the maximum stress, not in the entire length of the column. By being welded, the out-of-plane rigidity of the plastic hinge zones at the upper and lower ends of a concrete-filled rectangular steel tubular column is increased and reinforced, the steel tubular column is rationally reinforced, and the filling of concrete into the column is improved. .

At this time, since the reinforcement on the outside of the steel pipe column can be accommodated in the fireproof coating of the column or the finishing material, there is no design problem.

[0009]

The present invention will be described below with reference to the illustrated embodiments. Welded rectangular steel tube that is a constituent element of a rectangular steel tube column 1
A plate-shaped local buckling reinforcing steel pipe 2 extending in the direction parallel to the column axis was previously welded to the inside of the column, and the steel plate 1 with the reinforcing steel plate 2 was welded (see FIG. 2) to assemble the rectangular steel pipe column 3. After that (see FIG. 3), a flat plate-shaped concrete constraining reinforcing steel plate 4 extending in a direction perpendicular to the column axis of the same column 3 is welded to the outside of the same column steel pipe column 3 (see FIG. 4), and the rectangular steel pipe thus configured Concrete 3 is filled in the pillar 3 to form a concrete-filled rectangular steel pipe pillar A. (Refer to FIG. 1) Note that contrary to the above, the reinforcing steel plate 4 for concrete restraint may be welded to the inside of the column and the steel plate 2 for local buckling reinforcement may be welded to the outside of the column.

However, the former case has the advantage that the filling property of the concrete is better and the present invention can be applied to a cold-formed rectangular steel pipe produced by welding a U-shaped steel plate. In general, the pillar member produces maximum stresses at both upper and lower ends of the pillar when it receives an axial compressive force P as a constant load and a horizontal force Q as a short-term load such as an earthquake at the same time. Therefore, the above-mentioned reinforcement may be applied not only to the entire length of the column but only to the plastic hinge zones B at the upper and lower ends of the column.

In the embodiment shown in FIGS. 5 and 6, a flat plate-shaped local buckling reinforcing steel plate 2 extending in the column axial direction is welded to the inner surface of the column only in the plastic hinge zone B of the column in the rectangular steel tube column 3. The steel plate 2 increases the out-of-plane rigidity of the rectangular steel pipe column 3 and reinforces the hinge zone B. In the embodiment shown in FIGS. 7 and 8, a plate-shaped local buckling reinforcing steel plate 2 is welded to the rectangular steel tube column 3 in the direction perpendicular to the column axis only in the hinge zone B of the column.

In the embodiment shown in FIG. 9 (a), the reinforcing steel plates 2 are formed in a trapezoidal shape, adjacent steel plates 2 are in contact with each other, and a continuous frame having a large reinforcing effect is provided on the inner peripheral surface of the rectangular steel pipe column 3. The case where a strip-shaped reinforcing material is formed is shown. In FIG. 9B, a pentagonal reinforcing steel plate 2 is used, and adjacent steel plates 2 are arranged close to each other to increase the reinforcing effect.

[0013]

As described above, according to the present invention, a column-constituting element in which a local buckling reinforcing steel plate or a concrete restraining reinforcing steel plate is welded to the inner side surfaces at the upper and lower ends of a concrete-filled rectangular steel tubular column. By welding a steel plate for concrete restraint reinforcement or a steel plate for local buckling reinforcement to the outer surface of the upper and lower ends of a rectangular steel pipe column assembled from steel plates to be strengthened and stiffened the steel pipe column, It increases the restraining effect of the filled concrete, improves the toughness of the concrete-filled rectangular steel tubular column, and does not impair the concrete filling property.

Further, according to the present invention, the column member simultaneously receives an axial compressive force as a constant load and a horizontal force as a short-term load such as an earthquake without reinforcing the steel plate over the entire length of the column. By applying only to the upper and lower ends of the column that sometimes causes the maximum stress, the toughness of the concrete-filled rectangular steel tubular column is effectively improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of a concrete-filled rectangular steel tube column according to the present invention.

FIG. 2 is a vertical cross-sectional view of a steel plate welded with a local buckling reinforcing steel plate.

3 is a plan sectional view of a rectangular steel tube column assembled from the steel plate of FIG.

FIG. 4 is a plan view showing a state in which a reinforcing steel plate for concrete restraint is attached to the rectangular steel pipe column of FIG.

FIG. 5 is a plan view showing another embodiment of the concrete-filled rectangular steel plate column according to the present invention.

FIG. 6 is a longitudinal sectional view of a main part of the concrete-filled steel pipe column shown in FIG.

FIG. 7 is a plan sectional view showing still another embodiment of the concrete-filled rectangular steel tube column according to the present invention.

FIG. 8 is a vertical cross-sectional view of a main part of the concrete-filled steel pipe column shown in FIG.

9 (a) and 9 (b) are plan sectional views showing respective examples of the concrete-filled rectangular steel tube column according to the present invention.

10 (a) and 10 (b) are plan cross-sectional views showing the effect of restraining concrete-filled circular steel tubular columns and rectangular steel tubular columns with internally filled concrete under high axial force.

FIG. 11 is an explanatory diagram showing deformation of a concrete-filled rectangular steel tube column during an earthquake load.

[Explanation of symbols]

 A Concrete-filled square steel tube column B Plastic hinge zone 1 Steel plate 2 Steel plate for local buckling reinforcement 3 Square steel pipe column 4 Reinforcement steel plate for concrete restraint 5 Concrete

Front page continuation (72) Inventor Jun Kobayashi 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. (72) Kenyoshi Korenaga 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. (72) Inventor Hiroyuki Narihara 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd.

Claims (4)

[Claims] 1. A steel plate for locally buckling reinforcement in advance on the inner side surface at both upper and lower ends of a concrete-filled rectangular steel tubular column,
Or, the reinforcing steel plate for concrete restraint or the steel plate for local buckling reinforcement is welded to the outer surface of the upper and lower ends of the rectangular steel tube column which is assembled from the steel plate which is the element for forming the column to which the reinforcing steel plate for concrete restraint is welded. Concrete-filled rectangular steel tubular columns characterized by. 2. The concrete-filled rectangular steel tube column according to claim 1, wherein a reinforcing steel plate made of steel extending at right angles to the column axis is welded to the outer peripheral surface of the plastic hinge zone of the rectangular steel tube column. 3. The reinforcing steel plate extending in the axial direction of the column is welded to the inner peripheral surface of the plastic hinge zone of the rectangular steel column.
Concrete-filled prismatic steel tubular column described. 4. A polygonal reinforcing steel plate extending at right angles to a column axis is welded to an inner peripheral surface of a plastic hinge zone of the rectangular steel tubular column so that edges of the adjacent reinforcing steel plates are close to or in contact with each other. Item 1. A concrete-filled rectangular steel tubular column according to Item 1.