JPS5817863B2 - Reinforcement bar with flat section - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reinforcing bar having a flat portion, and more particularly to a reinforcing bar having a perfect circular cross section or a circular cross section similar to this.

Conventionally, when joining the ends of reinforcing bars having a circular cross section, the ends of reinforcing bars a and a' are overlapped with each other as shown in A and B in Fig. 1, and the ends are wrapped with wire or welded. Lap joints, which are joined by a lap joint, or butt joints, which are joined by welding or gas pressure welding by welding or gas pressure welding the ends of the reinforcing bars abutting each other in the axial direction, as shown in C and D, or butt joints, which are joined by welding or gas pressure welding, as shown in E. The sleeve b is fitted onto the outer periphery of the abutted ends using a sleeve joint, etc., and the reinforcing bars are arranged as shown in Fig. 2A.

As shown in B, the reinforcement arrangement in two axial directions is overlapped with each other.

However, in the lap joint in the above-mentioned end joint, since an eccentric distance e is created in the joint, for example, in a slab, the effective acid from the top of the poured concrete layer to the reinforcing bars is small.
Especially in the case of thin slabs, the efficiency of reinforcing bars against bending moments cannot be improved.

In addition, welded butt joints have higher reliability than other joints, but because they have a circular cross section, the reinforcing bar base metal tends to be insufficiently melted during the welding process, and is not suitable for welding, especially after reinforcing. In some cases, sufficient bonding and bonding strength cannot be obtained.

Furthermore, in the case of a sleeve joint, a sleeve and a compressor are essential, and the workability at high places after reinforcing is poor.

Furthermore, in the case of overlapped reinforcing bars, the efficiency of reinforcing bars cannot be improved in the same way as described above, since the above-mentioned example joints cause a kinematic distance e in the joints, similar to the overlapped joints.

The above-mentioned difficulties arise because all of the steel bars have a circular cross section.

Therefore, the present invention was developed as a result of studies in view of the above-mentioned difficulties, and it is a reinforcing bar having a circular cross section, at least at the end of the reinforcing bar and at other appropriate positions, which has approximately the same cross-sectional area as the circular cross section. It is characterized by the formation of flat parts, and its purpose is to provide reinforcing bars that can improve the weldability of coaxial butt joint welding between reinforcing bars or other base metals, as well as reinforcing bar efficiency and reinforcement accuracy. It's about doing.

The drawings showing embodiments of the present invention will be described below.

3A, B & In FIG. 3, the reinforcing bar 1 consists of a round steel cable 1' with a circular cross section of diameter d, the end 2 of which has the same cross-sectional area as that of the circular cross-sectional part 3. The widest part of the flat part 4 is at least twice the diameter of the circular cross section.

Also, from the end 2 in the longitudinal direction of the reinforcing bars, for example, the bar spacing, L...
...Flat parts 4', 4'' similar to the above on the mother...
The reinforcing bars 1 are formed by forming the reinforcing bars 1 at equal intervals as shown in FIG.

The flat parts 4, 4', 4"... are the ends of the round steel so that the reinforcing bars can be easily joined and connected to each other, and so as not to reduce the cross-sectional strength of the chain part. It is formed without any local cross-sectional defects in the reinforcing bars, and is formed by rolling the reinforcing bars during the rolling process, or by pressing the round steel cables of the reinforcing bars into a press with a circular blade type, as illustrated in Figures 4 and 5. It is pressed using a machine 5 to transform the mouth-shaped cross section into a flat rectangular cross section.

Also, the flat part has a streamlined shape when viewed from the side and the plane.
It is formed so that the force flows smoothly as shown in the figure.

That is, the flat part of the reinforcing bar is formed into an arc shape, and the cross-sectional area of the reinforcing bar at each position is made constant by making the flat part thinner as it becomes wider.

When forming with a press machine as mentioned above, compression chi,
For A, equal support and reaction ports are provided that face each other in opposite directions from the axial direction of the round steel cable material 1' to prevent the extension from extending in the axial direction, and instead to extend it in the direction perpendicular to the axial center expansion cover,
When forming the flattened portion 4 at the end portion by pressing, as shown in FIG.
It is best to apply compressive force to deform the ends while abutting each other, and in this way, the ends of two reinforcing bars can be flattened simultaneously in one step, which is convenient for later butting and joining of reinforcing bars.

As described above, the flat parts 4, 4', 4'', .

In the shape shown in B, the cross-sectional areas A' and A are A←BXt in the flat part and πd2A--7- in the circular cross-sectional part, and there is no difference between the two cross-sectional areas.

As shown in FIGS. 8A and 8H, the end joints of the reinforcing bars are made by joining the flat parts 4 and 4 of the respective ends by butt welding 6, and the welding is performed on the flat parts with a rectangular cross section. Depending on the part, the weldability is good and the base metal can be sufficiently melted down to the axial center, as in normal flat steel welding, and by applying additional welding in that state, it is possible to join with sufficient strength.

Furthermore, as shown in FIGS. 9A and 9B, butt welding with the steel frame 7 can also be performed in the same manner as described above.

Furthermore, as shown in Fig. 10, the overlapped reinforcing bars are arranged using flat parts 4', 4'', which are provided at predetermined intervals.
・Then, the reinforcing bars perpendicular to this are overlapped with their circular cross-sections, and the reinforcement for columns, beam hoops, and scrap reinforcements is as shown in Fig. 11, with flat parts 4/ ,
4//... are carried out overlappingly, and the main part is joined by butt welding.

At this time, it is preferable to interpose a short steel pipe 10 inside the reinforcing bar cage 9 to serve as a backing metal and fixation during welding.

Since reinforcing bars can be arranged in this way, for example, in the case of a slab, as shown in Fig. 12, from the upper end of the poured concrete layer 11 to the center of the upper reinforcing bars arranged in layers at the lower part of the slab, which is the tension side. The effective component d1 is larger than that in the case of reinforcing with conventional reinforcing bars by 1/ of the value obtained by dividing the wall thickness of the flat part from the diameter of the circular cross section.

Therefore, the efficiency of the reinforcing bars in resisting the tensile forces of the slab can be improved.

In addition, if the flat part is formed at predetermined intervals according to the reinforcement spacing, there will be no need to divide the reinforcement dimensions on site or in the factory, and there will be no overlap of reinforcements, resulting in increased stability and high precision. Reinforcement arrangement becomes possible.

As described above, according to the reinforcing bars of the present invention, due to the flat parts of the reinforcing bar ends, butt welding between reinforcing bars and butt welding with reinforcing bars can be performed with equally good weldability from the viewpoint of work and joint strength. Moreover, it can be easily performed without creating an eccentric distance in the joint, and the flat part has a cross-sectional area equivalent to the circular cross-sectional area of the pond, and is formed so that it has a streamlined shape when viewed from the side and from the plane. Therefore, the flow of the transmitted force becomes smooth, there is no decrease in cross-sectional strength, and therefore, a sufficiently satisfactory joint strength can be ensured.

In particular, the widest part of the flat part of the reinforcing bar is at least twice as wide as the circular cross-section, so the base material of the reinforcing bar is sufficiently melted and a strong welded joint is created. It serves as a reinforcing material for bending in the wide direction, and is desirable in terms of strength.

In addition, by forming a flat part from the end to the middle at each reinforcing interval, when assembling reinforcing bars in a valve shape at the site or in a factory, it is possible to overlap the reinforcing bars at the flat part, making it easier to connect the reinforcing bars. This makes it easier and does not cause positional deviation, which not only allows for stable reinforcement and highly accurate reinforcement and good workability, but also because the deflection distance of the upper and lower reinforcement in overlapped reinforcement becomes smaller. This is an extremely effective invention, as it can increase the efficiency of reinforcing bars against bending moments.

[Brief explanation of drawings]

The attached drawings, Figures 1 and 2, show known examples.
Figures A, B, C, D, and E show examples of known end joints of reinforcing bars with circular cross sections, and Figures 2 A and B show examples of overlapped reinforcement of the same reinforcing bars in plan and side views. Figures 3 to 12 show multiple examples of the present invention, Figures 3A and B are plan and side views of the reinforcing bar of the present invention, and Figures 4 and 5 are flat section processing of the same reinforcing bar. Figures 4A and 4B show examples of machining of flat parts of other parts of reinforcing bars, and side and plan views of the shapes thereof. Figure 6 is a plan view showing the flow of force in the flat part, Figure 7A
, B is each cross-sectional view taken along the line AA and line B-B in FIG. 6,
Figures 8A and B are plan and side views of butt joints between reinforcing bars, Figures 9A and B are plan and side views of butt joints between steel frames, and Figure 10 is an example of overlapped reinforcement. Side view shown, 1st
FIG. 1 is a plan view showing an example of reinforcement as a hoop reinforcement and a modified example of a butt joint at the end of the reinforcement, and FIG. 12 is a cross-sectional view of a slab showing an example of using reinforcing bars arranged in overlaps. 1...Reinforcement bar, 1'...Round steel material, 2.
...Reinforcing bar end, 3...Circular cross section, 4
, 4', 4"...Squamous part.

Claims (1)

[Claims] 1 A flat part is formed at any point from the end to the middle of a reinforcing bar with a circular cross section, and the flat part is formed in an arc shape, and the width of the widest part is at least twice the diameter of the circular cross section. ,
In addition, the flat part is made thinner as the flat part becomes wider, thereby making the cross-sectional area constant at each position of the reinforcing bar and improving the strength of butt welding at both ends of the reinforcing bar. Rebar with.