JPH0414551A - Core column - Google Patents

Abstract

PURPOSE:To provide compressive strength and compressive flexibility by bringing spiral bars into close contact with each other to form a cylindrical body, providing a supporting plate at the upper or lower end of the body and filling filling material into the body. CONSTITUTION:A spiral bar 1 is formed into a cylindrical body 2 with proper diameter, leaving a gap of about 0-2mm between adjacent bars, while a supporting plate 3 with a diameter larger than that of the body 2 is welded to the lower end of the body 2. And filling material 4 composed of high-strength concrete etc., is filled into the body 2 to form a core column A. As a result, the core column A is prevented from being embedded in a base slab.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a core column embedded in a high axial force reinforced concrete column such as a lower floor column of a super high-rise apartment building or an auxiliary column in a multi-story shear wall. be.

(Conventional technology) Lower floor columns of ultra-high-rise reinforced concrete buildings and attached columns on the lower floors of multi-story shear walls are repeatedly subjected to high axial compressive force and shear force during earthquakes, resulting in the core concrete being crushed and becoming brittle. It was causing major destruction.

Therefore, in the past, the core concrete was designed to be restrained only by stirrups against such high axial compressive force and repeated shear force, but with this level of stirrup, the core concrete could not be crushed. gradually progressed and showed behavior with poor toughness.

Therefore, in order to prevent the core concrete from collapsing, it is conceivable to increase the amount of tie reinforcements or main reinforcements. However, in the former case, although a large deformation performance can be ensured, the pitch of the stirrups becomes very small, so the concrete aggregate gets caught in the stirrups, making it difficult to place concrete properly, which can lead to problems. This results in a decrease in the strength and toughness of the column.

In the latter case, the bending strength of the columns and shear walls increases, making it difficult to design a structure that can handle the increased shear force, resulting in brittle shear failure.

Therefore, in order to solve the above-mentioned problems, in recent years, methods of burying core columns having high strength and high toughness in core concrete have been considered.

(Issues to solve the problem) However, if the bearing strength of the core column is increased as described above, the bearing stress at the bottom end of the core column will exceed the bearing strength of the foundation slab, and this will cause the There is a problem in that when subjected to repeated high axial compressive force or shear force, the core column itself becomes buried in the foundation slab and the column itself is destroyed.

The present invention has been made in view of the above problems, and an object thereof is to provide a core column in which the bearing pressure area of the lower end of the core column is increased as the yield strength of the core column is increased.

(Means for Achieving the Object) In order to achieve the above object, the core column of the present invention has spiral reinforcements closely connected to each other to form a cylindrical body, and bearing pressure is applied to at least one of the upper end and the lower end of the cylindrical body. The present invention is characterized in that a plate is provided and a filler is filled inside the cylindrical body.

(Function) According to the above configuration, the core column has a large compressive strength similar to that of steel pipe concrete due to the restraining action of the spiral reinforcement in a triaxial compression state and the compressive load action due to the close proximity of the spiral reinforcement. In addition to providing compressive toughness, it is possible to improve the adhesion and integrity of the concrete of the core column, and by providing a bearing plate,
Since the bearing area increases, even if the core column strength increases,
It is possible to prevent the core columns from being buried in the foundation slab.

(Example) An example of the present invention will be described in detail below based on the drawings.

FIG. 1 is a perspective view showing an embodiment of the core column A of the present invention.

The core column A is made of precast, and the spiral reinforcements 1 are closely connected to each other to form a cylindrical body 2 of an appropriate diameter.A bearing plate 3 is welded to the lower end of the cylindrical body 2, and a filler material is placed inside the cylindrical body 2. It is formed by filling 4.

The spiral reinforcement 1 is of an appropriate diameter depending on the strength of the core column A, and is closely spaced with a gap of about 0 to 2 m+o.

In addition, the diameter and length of the cylinder 2 are determined depending on the location where it is used, and as shown in Figures 0 and 0 of Figure 2, reinforcing bars 2a are provided in the center or on the inner surface. Good too.

The bearing plate 3 is made of steel, has a diameter larger than that of the cylindrical body 2, and is welded as shown in FIG. 3.

Note that the material of the filler 4 can be arbitrarily selected by the designer from high-strength concrete, concrete, mortar, cement paste, plaster, etc., depending on the strength required of the core column A.

In addition, this core column A is not limited to being made of precast as mentioned above, and as the diameter increases, the weight increases. Filling is also possible.

Moreover, what is shown in FIG. 9 is another embodiment in which bearing pressure plates 3 are provided at the upper end and the lower end, and the bearing pressure plate 3 at the upper end is
is welded while placed on the upper end of the cylindrical body 2, and is provided with a filler inlet 3a smaller than the inner diameter of the cylindrical body 2.

In this way, the core column A of the present invention has a restraint action in a triaxial compression state due to the spiral reinforcements 1, and a compressive load effect due to the close formation of the spiral reinforcements 1, compared to steel pipe concrete. In this case, it has compressive strength and compressive toughness that are almost the same as this steel pipe concrete.

Therefore, when used by being buried in the lower floor columns of super high-rise apartment buildings, the lower floor columns of high-rise wall-type apartment buildings, and the attached columns of the lower floors of multi-story earthquake-resistant walls, as shown in Figure 4, , it is possible to reduce the compressive axial force that was previously borne by cast-in-place concrete with insufficient properties, and the compressive force is borne by the core column A, which has high compressive strength and high compressive toughness. It becomes possible to construct a pillar with a

Furthermore, since core column A bears almost no tensile force,
It is possible to suppress an increase in bending strength and an increase in shear stress.

The core pillar A is arranged as shown in Figure 4 in plan view, but in the case of the lower floor pillar M of a super high-rise apartment building, the core pillar A is arranged as shown in Figure 6.
The method shown in Figure 0, the method shown in Figures ■ and ■ in Figure 7 for the accessory column n on the lower floor of a multi-story shear wall, and the method shown in Figure 8 for the lower floor column S of a high-rise wall type apartment building. Various methods can be considered.

In addition, in the vertical direction, as shown in Fig. As shown in the figure, bearing plates 3 are provided at both the upper and lower ends.

It goes without saying that the above arrangement method is not limited to this.

FIG. 13 shows that the core column A of the present invention shown in FIG. 0, ■, and 0 in FIG.
Figure 1 shows the results of measuring the axial strain by applying the compressive force as shown in Figure 1. From these results, the core column A of the present invention has a strength five times or more compared to a normal core column.

In addition, the diameters of Figure 0, ■, 0, and ■ in Figure 12 are 148 mm, 180 am, 202 mm, and 100 am, respectively.
The compressive stress degree σC is calculated using the following formula.

(Effects of the Invention) The present invention has the following effects by having the above configuration.

■ By forming a cylindrical body by placing spiral striations in close contact with each other, providing a bearing plate on at least one of the upper and lower ends of the cylindrical body, and filling the inside of the cylindrical body with a filler material, the core column is Since the bearing area of the lower end increases, even if the proof strength of the core column increases, it is possible to prevent the core column from being buried in the foundation slab.

■ Constraint action in triaxial compression state by spiral muscles,
Due to the effect of compressive load due to the closeness of the spiral reinforcements, the core column has compressive strength and compressive toughness similar to steel pipe concrete.

Furthermore, by increasing the material strength of the filler, the rigidity of the core column increases accordingly, making it possible to bear a larger force.

(2) The tensile strength of the core column is only as high as the tensile strength of the filler inside the cylinder because the spiral reinforcement hardly resists the tensile force in the axial direction of the core column.

■ By forming a core column with closely spaced spiral reinforcements, the outer circumferential surface is uneven, providing excellent adhesion to cast-in-place concrete.

■ You can freely select the overall diameter and length of the core column, the diameter and strength of the spiral reinforcement, the compressive strength of the filler, etc., so you can use the core column that suits your design. Therefore, the degree of freedom in design can be expanded.

[Brief explanation of drawings]

Figure 1 is a perspective view of the core column of the present invention, Figure 0 in Figure 2 is a plan view without reinforcing bars, and Figures ■ and 0 in the same figure are plan views with reinforcing bars installed. , Figure 3 is a vertical cross-sectional view, Figure 4
The figure is a cross-sectional view showing the state of use, Figure 5, figure 0, and figure ■ are longitudinal cross-sectional views, showing the state of use, figure 6, figure 0 to 0, figure 7, figure 0, figure ■, and figure 8. is a cross-sectional view showing other usage conditions,
Figure 9 is the front view of the core column with bearing plates at the upper and lower ends, Figure 10 is the same plan view, Figure 11 is the front view showing the state with no load applied, Figure 12 is Figure 0, Figure ■. , Figure 0 is a cross-sectional view of core columns with different diameters, ■ figure in the same figure is a cross-sectional view of a conventional core column, Figure 13 is the core of figure 0, ■ figure, figure 0, ■ figure in figure 12. FIG. 3 is a measurement diagram showing the axial strain of a column. In the figure, A: Core column 1: Spiral muscle 2: Cylindrical body 3: Bearing plate 4: Filler.

Claims (1)

[Claims] A core characterized in that a cylindrical body is formed by forming spiral striations in close contact with each other, a bearing plate is provided on at least one of the upper end and the lower end of the cylindrical body, and a filler is filled inside the cylindrical body. Pillar.