JPH0519442Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a flat cross-section column in reinforced concrete construction or steel-frame reinforced concrete construction.

``Prior Art'' This type of flat cross-section column, typified by a column with a wall-type rigid-frame structure, is formed as shown in FIG. In the figure, A is a flat cross-section column, 1 is a column main reinforcement, and 2
is shear reinforcing bar, 3 is restraining bar (width stopping type),
4 is poured concrete.

This flat column has a much larger bending strength than a square cross-section column with the same cross-sectional area and the same amount of main reinforcement.
Moreover, it has been shown that if shear reinforcement is applied to match the shear force during the mechanism, bending failure can be postponed, resulting in greater deformation capacity.

``Problem to be solved by the invention'' On the other hand, bending failure due to seismic force in the girder direction (horizontal direction in Figure 4) of a flat cross-section column is caused by compression and bending compression of the concrete on both sides of the flat cross-section column, that is, the bending compression side. It has been found that this is caused by buckling of the main reinforcement of the side columns, and in order to increase the bending strength and deformation capacity, the purpose is to increase the strength and compressive toughness through the restraint effect of concrete and prevent buckling of the main reinforcement of the columns. Effective reinforcing measures are required.

However, at present, restraint bars such as width stop bars are only placed on the main column reinforcements, and we believe that it is necessary to develop more effective reinforcement methods in order to further increase strength and deformation capacity. It is being

Therefore, the present invention considers both sides of a flat cross-section column as a virtual compression part, and aims to increase the appropriate restraint effect of concrete and prevent buckling of the main reinforcement of the column in the virtual compression part or the central part, or even in both. The aim is to increase the strength and deformability of the steel by taking reinforcing measures.

"Means for Solving the Problem" In order to achieve the above object, the present invention provides a reinforced concrete construction or steel-frame reinforced concrete in which shear reinforcing bars 2 are appropriately installed around the entire main column reinforcement 1 and concrete 4 is poured. In the flat cross-section column A of the structure, the shear reinforcing bars 2 are installed around the column main reinforcements 1 in one or both groups of the virtual compression part Aa on both sides in the column direction and the central part Ao between both the virtual compression parts. It is characterized by the addition of an angular spiral muscle 5.

Here, the imaginary compressed portion Aa refers to a portion where bending compressive stress is generated when the flat cross-section column 1 receives a bending moment due to an earthquake force in the longitudinal direction of the column. Although it goes without saying that the seismic force that causes the bending moment acts from all directions, only the bending moment due to the seismic force in the column direction is considered here and is referred to as a virtual compression section.

"Function" Since the structure is as described above, the square spiral reinforcement 5 used separately from the shear reinforcing reinforcement 2 can be applied to the concrete 4 in the virtual compression part Aa on the bending compression side or the concrete 4 in the central part Ao between both virtual compression parts. Both concretes are restrained, and the strength and compressive toughness of the concrete are increased due to the restraint effect, and buckling of the column main reinforcement 1 can be prevented. Therefore, in the virtual compression part Aa on the bending compression side, against bending compression failure,
In the central part Ao between both virtual compression parts, it acts effectively against compression failure due to axial force.

As a result, the horizontal yield strength (bending strength, shear strength) of the column member as a whole increases, and the deformation capacity also increases dramatically.

The reason why this deformation ability increases is as follows.

When the flat cross-section column A undergoes rotational deformation in the beam direction due to the bending moment due to the seismic force, a larger compressive strain at the outermost edge than that of the square cross-section column is generated in the virtual compression part Aa of the flat cross-section column A. Therefore, if we consider that concrete will collapse when it reaches the critical compressive strain, the critical rotational deformation of flat cross-section column A will be smaller than that of square cross-section column, but the virtual compression section
When Aa is reinforced with the square spiral reinforcements 5, the critical compressive strain of the concrete 4 increases, and the deformation capacity of the column member increases.

Similarly, when flat cross-section column A undergoes rotational deformation in the beam direction due to bending moment due to seismic force, in the central part Ao between both virtual compression parts Aa of flat cross-section column A, this central part is strong. Acts as a core material. That is, when the concrete in the virtual compressed areas Aa at both ends is crushed and the concrete peels off, in the conventional flat cross section column, the reduction in the column cross section causes the fracture due to the axial force to progress. however,
If there is a rigid part formed by the square spiral muscle 5 in the central part Ao, this part prevents the progress of destruction due to axial force.

Next, in wall-type rigid-frame structures that employ flat cross-section columns, seismic forces in the direction between the beams are usually resisted by multi-layered shear walls. That is, generally, a multi-layer shear wall is provided in the beam-to-beam direction between the center portions Ao of the facing flat cross-section columns. In this case, when the multi-story shear wall receives seismic force in the wall direction (beam-to-beam direction), a large compressive force acts on the side columns on the compression side. For this compressive force,
The central part Ao acts as a core material as before,
Prevents crushing due to axial force.

"Embodiment" FIGS. 1 to 3 show an embodiment of the present invention.

What is shown in the figure is a flat cross-section column A made of reinforced concrete, with main reinforcement bars in each group between the imaginary compressed area Aa on both sides of the column in the column direction (left and right direction in Figure 3) and the central area Ao between both imaginary compressed areas. A square spiral reinforcement 5 is installed around each column 1, and the entire column main reinforcement 1 is attached.
A plurality of shear reinforcing bars 2 are installed around the concrete 4, and a predetermined amount of concrete 4 is poured. The square spiral reinforcing bars 5 may be ordinary reinforcing bars or high-strength reinforcing bars. The shear reinforcing bars 2 may be those commonly used in the past.

In principle, the shear force during the mechanism is borne by the conventional shear reinforcing bars 2, but if it becomes possible to quantitatively evaluate the increase in yield strength due to square spiral bars in the future, it will be possible to It seems necessary to consider this as well.

"Effects of the invention" According to the invention, in a flat cross-section column A made of reinforced concrete or steel-framed reinforced concrete, in which shear reinforcing bars 2 are suitably installed around the entire main column reinforcement 1 and concrete 4 is cast, In addition to the shear reinforcing bars 2, square spiral reinforcements 5 are installed around the column main reinforcements 1 in one or both groups of the virtual compression part Aa on both sides in the column direction and the central part Ao between both the virtual compression parts. Since it is installed, the concrete 4 in the virtual compression part Aa, the concrete 4 in the central part Ao between both virtual compression parts, or both concrete can be restrained by the square spiral reinforcement 5 used separately from the shear reinforcing reinforcement 2, and the concrete The strength and compressive toughness of the column main reinforcement 1 can be increased, and buckling of the column main reinforcement 1 can be prevented. Therefore, the virtual compression part Aa on the bending compression side can effectively act against bending compression failure, and the central part Ao between both virtual compression parts can effectively act against compression failure due to axial force.

Therefore, the horizontal strength and deformation capacity of the entire column member can be increased regardless of whether the square spiral reinforcement 5 is attached to either of the virtual compression parts Aa or the central part Ao. For example, due to the synergistic effect, its horizontal strength and deformation capacity can be dramatically increased.

[Brief explanation of the drawing]

Figures 1 to 3 show embodiments of the present invention.
The figure is a cutaway perspective view, FIG. 2 is an enlarged longitudinal sectional side view of the main part, FIG. 3 is a cross-sectional plan view of the same, and FIG. 4 is a cross-sectional plan view showing a conventional example. A...Flat cross-section column, Aa...Virtual compression section, Ao...
...Central part, 1...Column main reinforcement, 2...Shear reinforcement,
3...Restraint bar, 4...Poured concrete, 5...
corner spiral.

Claims (1)

[Scope of utility model registration request] Appropriate shear reinforcing bars 2 are placed around the entire column main bar 1.
In a flat cross-section column A of reinforced concrete construction or steel-framed reinforced concrete construction, in which a concrete 4 is installed and concrete 4 is cast, one of the virtual compressed parts Aa on both sides in the column direction and the central part Ao between both virtual compressed parts A flat cross-section column characterized in that square spiral reinforcements 5 are installed around the main column reinforcements 1 of both groups, separately from the shear reinforcing reinforcements 2.