JPS626063B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in reinforced concrete columns.

The pillar member has two functions: supporting axial force and resisting horizontal force. Among these, the larger the cross-sectional area, the safer it is against axial force, while deformation ability is required against horizontal force.

In general, reinforced concrete columns are susceptible to shear failure when the ratio of column height D to column length (floor height) H is small.
In this case, toughness is poor.

Figure 1 shows the reinforcement arrangement of reinforced concrete structural frames that are currently commonly constructed.The main column reinforcement 1 is designed to be safe against bending stress, and the hoop reinforcement 2 is designed to be safe against shearing stress.

However, with conventional methods, it is not easy to safely design against shear forces, and in particular, as H/D becomes smaller, the amount of hoop reinforcement increases to obtain the required shear resistance, making construction easier on site. Not.

Further, even if the required shear strength can be secured, if the H/D is small, the yield strength after the maximum yield strength is often reduced as shown by the broken line in FIG. 6.

Furthermore, if columns are to be prefabricated, in the case of high-rise buildings or buildings with large floor heights, the weight of each column increases, making it difficult to manufacture using conventional factory equipment.

The present invention has been proposed to solve these problems, and involves imagining a reinforced concrete column having a required design cross section and column length, and dividing the virtual reinforced concrete column along its axis. In addition to sufficiently increasing the ratio of the column length to the strength of the plurality of column pieces obtained through the process, each column piece is individually subjected to bending reinforcement and shear reinforcement to make the column into a bending failure type, thereby achieving the required toughness of the column. This relates to a reinforced concrete column characterized by being made by imparting strength.

In the present invention, we assume a reinforced concrete column that satisfies the required design requirements, that is, has a required design cross section and a required design length, and divide this virtual reinforced concrete along the column axis into a plurality of mutually independent columns. The actual reinforced concrete column is made up of column pieces, and each column piece is independently reinforced in bending and shear.In this way, each column piece has a column length H that does not change, but the column length H remains unchanged. As the ratio D decreases, H/D increases. In the present invention, by making this H/D sufficiently large, each column piece becomes a column material of a bending fracture type.

As described above, according to the present invention, a reinforced concrete column can be changed from a shear failure type to a bending failure type with high toughness without losing its function against axial force, and a large cross-section column can be prefabricated. In this case, by dividing the column into a plurality of column pieces within the same cross section, transportation, lifting, etc. can be made easier without impairing the mechanical properties.

The present invention will be described below with reference to the illustrated embodiments.

FIG. 2 shows a cross section of a secondary reinforced concrete column, in which hoop reinforcements 2 surround the main reinforcement 1, and connecting reinforcements 3 are connected between the opposing hoop reinforcements 2.

3 and 4 show cross sections of each embodiment of the reinforced concrete column according to the present invention. The column shown in FIG. 2 is divided along the axis direction, and each column piece a,
Main reinforcing bars 1, hoop reinforcing bars 2, and tethering bars 3 are independently arranged in a, and bending reinforcement and shear reinforcement are performed separately for each reinforcement.

Now, when a large horizontal force Q is applied to the column of the present invention during an earthquake, etc., the column will crack along the part where there is no hoop reinforcement 2 at the boundary between each divided column a, a, as shown in Fig. 7B. It occurs in the direction of the material axis, and as shown in Fig. 7C,
After bending cracks occur as shown in D, a bending yield type fracture with high toughness occurs, resulting in
This is completely different from the conventional reinforced concrete columns, which were of the shear failure type as seen in D to D, and as described above, according to the present invention, by changing the shear failure type columns to the bending yield type, the required Fig. 6 shows a load deformation curve corresponding to the applied force model of Fig. 5.

In the column shown in Fig. 3, as mentioned above, in the event of a large earthquake, cracks will appear in the axial direction of the material along the cuts in the hoop reinforcement 2 in the area where there is no hoop reinforcement 2, which is the boundary between the column pieces a and a. By inserting a joint 4 along the cut of the hoop reinforcement 2, the joint 4 can be used against earthquakes that may be experienced several times during the service life.
Internal cracks are not noticeable, so you may not need to repair them every time.

In addition, it is inevitable that cracks will occur along the axis of the divided material of the column, so the hoop reinforcement
A release material 5 may be interposed in the cut to make it mechanically clear. (See Fig. 4) Fig. 9 shows an example in which the present invention is applied to a pillar of the conventional construction method. , a, a joint filler 6, a release material 5, and a release material 5 and a joint filler 6 are interposed as necessary at the locations where the hoop lines are broken.

Figure 10 shows a case where the present invention is applied to a column using the reinforced concrete prefabricated construction method, in which PC column pieces a vertically divided in a straight or cross shape along the column axis are joined on site and Reinforcement is arranged for each member like a single column.

In the present invention, as described above, each divided column formed by dividing a reinforced concrete column material along the material axis is independently reinforced by bending and shearing,
Required toughness and strength can be imparted to reinforced concrete columns, which conventionally were of shear failure type, by making them bending yield type.If the present invention is applied to the reinforced concrete prefabrication method, column members can be Since it can be divided in the axial direction of the material, problems with transportation and lifting can be solved.

Furthermore, as described above, according to the present invention, toughness that could not be obtained with conventional reinforced concrete columns can be obtained, so the present invention has many advantages, such as making it possible to build high-rise reinforced concrete structures.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

Figure 1 is a bar arrangement diagram of a reinforced concrete structure frame constructed using a conventional construction method, Figure 2 is a cross-sectional plan view of a reinforced concrete column constructed using a conventional construction method, and Figures 3 and 4 are cross-sectional views showing each embodiment of a reinforced concrete column according to the present invention. A plan view, FIG. 5 is a model diagram of the force applied to the column of the present invention, FIG. 6 is its load deformation curve, and FIG. 7A,
B, C, D and FIGS. 8A, B, C, and D are explanatory diagrams showing the fracture process of the reinforced concrete column according to the present invention and the fracture process of the conventional reinforced concrete column, respectively;
FIG. 9 and FIG. 10 are a front view and a cross-sectional plan view showing an embodiment in which the present invention is applied to a conventional reinforced concrete construction method and a reinforced concrete prefabricated construction method, respectively. a... Column piece, 1... Main reinforcement, 2... Hoop reinforcement.

Claims (1)

[Claims] 1. Imagine a reinforced concrete column with the required design cross section and column length, and divide the virtual reinforced concrete column along its axis to sufficiently increase the ratio of column length to column length of multiple column pieces. A reinforced concrete column is characterized in that each of the column pieces is independently subjected to bending reinforcement and shear reinforcement to make the column bendable and breakable, thereby imparting the required toughness and strength to the column.