JP2575754Y2 - Rectangular steel tube concrete column - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete column made of a rectangular steel pipe for construction, which is formed by filling a rectangular steel pipe with concrete.

[0002]

2. Description of the Related Art As a steel pipe used in a steel pipe-filled concrete method, there are a circular steel pipe and a rectangular steel pipe. When a circular steel pipe is used, the cross-sectional performance as a column is better than that of a rectangular steel pipe and the steel pipe has a better cross section performance. There is an advantage that the steel plate is also strong against local buckling. Further, the concrete has a large restraining force inside the steel pipe that receives an axial force, and has better mechanical strength performance than a rectangular steel pipe.

On the other hand, rectangular pillars are more desirable than round pillars from the viewpoint of building planning. Therefore, cost and performance are both inferior, but rectangular steel tubular concrete pillars are often used.
Stud bolts are welded to the inside of the steel pipe to prevent local buckling, and inserts are inserted into the symmetry plane of the rectangular steel pipe to prevent the steel sheet constituting the steel pipe from locally buckling and protruding out of the plane of the steel sheet. .

[0004]

However, such a conventional rectangular steel tubular concrete column receives a large axial force at all times, and a large bending moment is applied to the column cap and the column base during an earthquake. The steel pipe steel plate receives a large compressive force in the plane due to the force and bending moment, and also receives an out-of-plane force due to the overflow of the internal concrete, causing local buckling of the steel plate, causing a sudden decrease in proof stress. there were.

The present invention has been made in view of the above-mentioned conventional problems. A hoop-shaped reinforcing steel is applied to a steel plate to increase the binding force of the concrete filled inside the welded steel pipe and to support the outside of the steel plate surface. This effectively prevents the local buckling of the steel sheet, thereby obtaining a rectangular steel tube concrete column capable of providing sufficient strength against the in-plane force caused by the bending force due to the axial force and the horizontal force during an earthquake or the like. The purpose is to:

[0006]

According to the present invention, a rectangular steel pipe concrete column having a steel plate buckling prevention is formed by combining steel plates in a box shape and welding the joints to form the rectangular steel pipe. A plurality of hoop-shaped reinforcing bars welded so as to protrude substantially in the horizontal direction are provided on the inner surface of each steel plate, and concrete is filled in a rectangular steel pipe having the reinforcing bars.

[0007]

The hoop-shaped reinforcing bar in the present invention has a part fixed to each steel plate constituting the rectangular steel pipe, and the other part protrudes horizontally and deeply into the steel pipe. For this reason, when a part of the concrete filled in the rectangular steel pipe is confined in the hoop-shaped reinforcing bar protruding in the horizontal direction and receives a bending moment due to an axial force or a horizontal force due to an earthquake, the hoop is prevented. It acts to increase the restraining force of the concrete by the reinforcing bar, thereby functioning to minimize the protrusion of the concrete.

As a result, it is possible to avoid the occurrence of local buckling by restraining the out-of-plane force acting on each steel plate constituting the rectangular steel pipe due to the protrusion of concrete as in the prior art, and supporting the steel plate out of the plane. To improve the strength and toughness of the rectangular steel tubular concrete column and prevent a sudden decrease in proof stress.

[0009]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG.
1 is a plan sectional view showing a rectangular steel pipe concrete column having buckling prevention of a steel plate of the present invention, in which 1 is a rectangular steel pipe, which is a combination of four steel plates 2 of a predetermined width in a box shape, It consists of a welded corner. W is the weld.

Reference numeral 3 denotes a hoop-shaped reinforcing bar, which is welded to the inner surface of each steel plate 2 in such a manner that a plurality of the bars are protruded in the vertical direction in a horizontal direction. Each of these rebars 3 is provided so as to protrude so as to reach a majority portion in the rectangular steel pipe 1, that is, the vicinity of the inner surface of each of the opposed steel plates 2, and are arranged so as not to interfere in the horizontal direction. Therefore,
The reinforcing bars 3 on each steel plate 2 overlap or interfere (contact) with each other in the vertical direction via a gap.

Further, a concrete 4 is filled in a rectangular steel pipe 1 composed of four steel plates 2 to which the above-mentioned reinforcing bars 3 are welded, and each reinforcing bar 3 is buried in the concrete 4.
The concrete 4 is restrained in the hoop.

FIG. 2 is an internal explanatory view of the rectangular steel pipe 1 showing the arrangement of the hoop-shaped reinforcing bars 3 with respect to the respective steel plates 2. Each reinforcing bar 3 is fixed to the inner surface of each steel plate 2 at a welded portion X in the horizontal direction. ing.

Therefore, in the concrete column made of the rectangular steel pipe having the steel plate buckling prevention having such a structure, when the large axial force F as shown in FIGS. However, at this time, a force f in a protruding direction is generated in the concrete 4 inside, and this acts on the inner surface of each steel plate 2.

However, most of the force in the protruding direction acts on the hoop of the reinforcing bar 3, and the protruding force beyond the hoop is prevented. Then, only a small force f1 in the protruding direction generated outside the hoop acts on each steel plate 2, and the steel plate locally buckles due to the in-plane force of f2, but the rectangular steel pipe is formed by the out-of-plane support force of the warp of the reinforcing bar. The buckling resistance of 1 and 2 is sufficiently enhanced.

In the above embodiment, the rectangular steel pipe 1 is formed by combining four steel plates 2 in a box shape. However, instead of this, two U-shaped steel plates face each other to form a box shape. The same effect as in the above embodiment can be obtained by attaching the above-mentioned hoop-shaped rebar similarly to a rectangular steel pipe concrete column which is made into a rectangular steel pipe by welding each joint.

[0016]

[Effect of the Invention] As described above, according to the invention, a rectangular steel pipe formed by combining steel plates in a box shape and welding the joints,
On the inner surface of each steel plate forming the rectangular steel pipe, a plurality of hoop-shaped rebars welded so as to project substantially in the horizontal direction are provided, and concrete is filled in the rectangular steel pipe having the rebars. As a result, part of the concrete filled in the rectangular steel pipe was restrained by the hoop-shaped reinforcing bar protruding in the horizontal direction, and the steel plate was supported out-of-plane and received horizontal and axial forces due to the earthquake. In such a case, the restraining force of the rebar can suppress the overhang of the concrete, and can also avoid the occurrence of local buckling of the steel plate of the rectangular steel pipe, and can reliably prevent the reduction of the strength of the rectangular steel pipe concrete column. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing a rectangular steel tube concrete column having a steel plate buckling according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a mounting structure of a hoop-shaped rebar to a steel plate in FIG. 1;

FIG. 3 is an explanatory front view showing the anti-buckling performance of the rectangular steel pipe according to the present invention.

FIG. 4 is an explanatory plan view showing the restraining effect of the rectangular steel pipe concrete according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectangular steel pipe 2 Steel plate 3 Rebar 4 Concrete

Claims (1)

(57) [Scope of request for utility model registration] 1. A rectangular steel pipe formed by combining steel sheets in a box shape and welding a joint portion, and a plurality of steel pipes welded to the inner surface of each steel sheet forming the rectangular steel pipe so as to project in a substantially horizontal direction. A rectangular steel tube concrete column comprising: a hoop-shaped reinforcing steel; and concrete filled in a rectangular steel pipe having the reinforcing steel.