JPH05248037A - Reinforcing bar for shearing - Google Patents

Abstract

PURPOSE:To form a reinforcing bar having high earthquake resistant effect without using welding structure, by setting the bending angle of a hook to a certain value or more, and installing the hook at the engagement position with a main stem other than four corners of a pillar or beam. CONSTITUTION:A reinforcing bar 8 for shearing is arranged so that a hook 9 is engaged with a main stem 11 at a position separated from four corner parts. The bending angle of the hook is set at 135 deg. or more. As for the reinforcing bar 8 for shearing, even if the concrete at four corners of a pillar and beam is cut, the hook 9 is left in the firmly engaged state with the main stem 11 at the part where the concrete is not cut, and acts to the full limit of the tensile strength of the reinforcing bar 8 for shearing, for the destruction of the pillar and beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the shape of a shear reinforcing bar with a hook used in an RC structure.

[0002]

2. Description of the Related Art When a column or beam of a reinforced concrete building has an RC structure, a shear reinforcing bar called a hoop or stirrup is provided around the main bar so as to surround the main bar arranged in the longitudinal direction of the column or beam. And bury it in concrete. As shown in FIG. 2, conventionally, such a shear reinforcing bar has a shape obtained by bending a deformed rebar into a square or rectangular shape surrounding the outer periphery of the main bar 10, and the hooks 2 are provided at the corners. Had formed.

[0003]

FIG. 4 shows a cross section of a column 3 having an RC structure in which such a main bar 10 and a conventional shear reinforcing bar 1 are combined. FIG. 4B shows a pattern in which the concrete 4 of the pillar 3 having the cross section shown in FIG. 4A is destroyed during an earthquake. RC using shear reinforcement with hook
In the process in which a structural pillar or beam is destroyed by a strong earthquake, first, as shown in FIG. 4B, the concrete 5 at the four corners of the pillar or beam is missing, and the shear reinforcing bar and the main bar 10 are exposed. . After that, as shown in FIG. 4 (c), it is known that the shear reinforcing bar 1 causes a moment 7 to act on the portion of the hook 2 by pulling, causing deformation 6 of the hook, and finally breaking.

Therefore, in order to solve the problem of the conventional shear reinforcing bar with a hook, as shown in FIG. 3, a shear reinforcing bar having a welded structure without hooks has begun to be used. However, the shear reinforcing bar of the welded structure has a problem that it requires a lot of welding work, the tensile strength of the welded portion is lower than that of other portions, and the heat-affected zone exhibits brittleness, resulting in poor toughness. An object of the present invention is to provide a shape of a shear reinforcing bar that solves these conventional problems.

[0005]

Conventionally, the hook portion of the shear reinforcing bar with a hook has been attached to the main bars at the four corners of a column or a beam, but in the present invention, the hooks are locked to the main bars other than the four corners.
That is, in the present invention, in the shear reinforcing bar with hook used for the RC structure, the bending angle of the hook is set to an angle of 135 ° or more and the position of the hook is locked to the main bar other than the four corners of the column or the beam. It is a shear reinforcement bar characterized by being provided in.

[0006]

In the shear reinforcing bar of the present invention, the hooks are locked to the main bars other than the four corners. Therefore, even if the concrete or the four corners of the RC structure column or beam subjected to seismic load is damaged, The hook portion of the reinforcing bar is not exposed to the outside. Therefore, the hook is not deformed and the performance as the shear reinforcing bar is not lost. Further, since it is not a welded structure, it requires less labor and is highly reliable.

[0007]

FIG. 1 is a schematic view of an embodiment of the present invention. The shear reinforcing bar 8 has a shape in which a hook 9 is engaged with a main bar 11 at a position apart from four corners. The bending angle of this hook is 180 °. Such shear reinforcements 8 are
Even if the concrete in the corner is missing, the hook is left firmly fixed to the main bar 11 where it does not drop, and acts on the tensile strength of the shear reinforcing bar up to the limit of the breaking strength of the column or beam. The reliability is markedly higher than that of the shear reinforcement with hook and the shear reinforcement of welded structure.

[0008]

As described above, according to the present invention, since the hook is surely kept in the state of being locked to the main bar, it greatly contributes to the improvement of the toughness of the RC structure column or beam.

[Brief description of drawings]

FIG. 1 is a plan view of a shear reinforcing bar of an example.

FIG. 2 is a plan view of a conventional shear reinforcing bar.

FIG. 3 is a plan view of a shear reinforcing bar of a welded structure.

FIG. 4 is an explanatory diagram showing destruction in the RC structure.

[Explanation of symbols]

 1 Shear Reinforcing Bar 2 Hook 3 RC Structural Column 4 Concrete 5 Missing 6 Hook Deformation 7 Moment 8 Shear Reinforcing Bar 9 Hook 10, 11 Main Bar

Claims (1)

[Claims] 1. A shear reinforcing bar with a hook used for an RC structure, wherein the bending angle of the hook is set to 135 ° or more, and the position of the hook is provided at a portion other than the four corners of the column or the beam to be locked to the main bar. Shear reinforcement that is characterized by