JPH0542443U - Opening reinforcement - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an opening reinforcing bar having a reinforcing bar which is resistant to cracking in a fracture region extending in a tangential direction at an angle of about 45 ° in contact with an opening of a beam. [Structure] A plurality of ring reinforcements 1 arranged in multiple layers inside and outside are integrally joined with an oblique reinforcing reinforcement 2 from an inner ring reinforcement 1 to an outer ring reinforcement 1, and the diagonal reinforcement 2 is connected to an inner ring. It is arranged so as to extend in the tangential direction of the muscle 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention particularly relates to an opening reinforcing bar of a reinforced concrete (RC) beam or a steel frame reinforced concrete (SRC) beam.

[0002]

[Prior Art]

 Conventionally, this type of RC or SRC beam opening reinforcement has a plurality of ring reinforcements R arranged concentrically and connected by radial branch reinforcements E to form reinforcement as shown in FIG. The reinforcing bar is arranged around the opening b of the beam B.

According to strength experiments conducted by the present inventors, the above-mentioned conventional reinforcing bar is broken by the breaking lines C1 and C2 of 45 ° and 60 ° diagonally extending in contact with the opening b of the beam B. It was found that the shear cracks in the region C 3 were likely to expand. The ring streak is the normal fracture line. 45 ° cracks passing through the center of the opening are constrained to increase the yield strength of the opening. As a result, the crack concentrates in the fracture area C where the reinforcing effect decreases for more loads. This is because. In the fracture region C, the ring muscle R is not orthogonal to the crack direction, and it becomes difficult to exert sufficient crack resistance, and the conventional branch muscle E directly contacts the crack. This is because it is difficult to work.

[0004]

[Problems to be solved by the device]

 The present invention is intended to further enhance the reinforcing ability of the conventional reinforcing bar. By devising the direction of the conventional bar reinforcement E, it is possible to prevent cracks that tend to occur in the above fracture area. The present invention is to provide an aperture reinforcing bar for RC or SRC beams, which can effectively work as a result and can improve the yield strength of the beam.

[0005]

[Means for Solving the Problems]

 The opening reinforcement of the present invention integrally joins the diagonal reinforcements from the inner ring reinforcement to the outer ring reinforcement of a plurality of inner and outer ring reinforcements, and connects the diagonal reinforcement reinforcements to the inner reinforcement. It is characterized in that it is arranged so as to extend in the tangential direction of the ring muscle. In addition, four diagonal reinforcing bars are provided, and the inner ends of the four diagonal reinforcing bars are arranged at respective positions that divide the circumference of the inner ring reinforcing bar into four equal parts, and the four diagonal reinforcing bars are arranged. Divide into two pairs of diagonal reinforcements that are adjacent to each other, and the two diagonal reinforcements of each pair or their extension lines intersect each other. It is also characterized by arranging so as to extend in the tangential direction of the inner ring muscle.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a ring bar, which is formed by bending a reinforcing bar such as a hard steel wire into a ring shape and butt-welding both ends 1a thereof into an annular shape. In this embodiment, three ring muscles 1 each having a different diameter are arranged in concentric circles from the inner side at appropriate intervals.

It is preferable that the diameter of each of the three ring reinforcements 1, the distance between them, the diameter of the reinforcement, and the like are appropriately determined according to the size of the beam to be reinforced, the diameter of the opening, and the like. Further, the combination of the respective ring muscles 1 is not limited to triple as in the present embodiment, but may be double, quadruple, quintuple, etc. as long as they are arranged in multiple. The ring muscles 1 that are multiply arranged may be arranged so as to be eccentric to each other.

Reference numeral 2 denotes diagonal reinforcing bars, and four diagonal reinforcing bars are arranged so as to traverse each ring muscle 1 from the inner ring muscle 1 to the outer ring muscle 1. The intersections of the ring reinforcements 1 and the diagonal reinforcement reinforcements 2 are welded to each other and are integrally formed as a whole.

The inner ends 2a of the four diagonal reinforcing bars 2 are arranged at respective positions that divide the circumference of the inner ring reinforcing bar 1 into approximately four equal parts. Of the four diagonal reinforcements 2, the two adjacent diagonal reinforcements 2 are divided into two pairs, and each pair of two diagonal reinforcements 2 or their extension lines The inner ring muscles 1 are arranged so as to extend tangentially to intersect each other.

Since the opening reinforcing bar of the above embodiment is configured as described above, in order to arrange the reinforcing bar around the opening of the beam, as shown in FIG. 2 and FIG. The ring muscles 1 are concentrically arranged around the sleeve 4 of the opening 3a. At this time, the diagonal reinforcing bar 2 is arranged in a direction substantially orthogonal to the 45 ° tangent line L of the opening 3a of the beam 3.

Therefore, as is apparent from FIG. 2, the diagonal reinforcing bar 2 is provided in a direction orthogonal to the fracture region C between the 45 ° fracture line C1 and the 60 ° fracture line C2. Since it is reinforced, shear cracks in the opening can be effectively prevented.

FIG. 4 shows another embodiment, in which a part of the inner ring reinforcement 1 and the left and right diagonal reinforcements 2 are integrally formed, and a V-shaped reinforcement 6 is connected by an arcuate reinforcement 6. By doing so, the same crack prevention effect as that of the first embodiment is provided. In this embodiment, the straight portion 5a of the dogleg-shaped reinforcing bar 5 has the same function as that of the diagonal reinforcing bar 2.

[0013]

[Effect of the device]

 1) By arranging the reinforcing bars so as to be orthogonal to the fracture area along the 45 ° tangent of the beam opening, it is possible to effectively prevent shear cracks that tend to occur in this area. 2) The structure is simple and the manufacturing cost is low.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of an opening reinforcing bar of the present invention.

FIG. 2 is an explanatory view of the reinforcement of the opening reinforcing bar of the present invention.

3 is a cross-sectional view taken along the line EE of FIG.

FIG. 4 is a front view of an opening reinforcing bar showing another embodiment.

FIG. 5 is an explanatory view of a conventional opening reinforcing bar.

[Explanation of symbols]

 1 Ring Reinforcement 1a Both Ends 2 Oblique Reinforcement 2a Inner End 3 Beam 3a Opening 3b Longitudinal Axis 4 Sleeve 5 V-shaped Reinforcing Bar 5a Straight Part 6 Arcuate Reinforcement C Crash Area C1 45 ° Failure Line C2 60 ° Failure Line L 45 ° tangent

Claims (2)

[Scope of utility model registration request] 1. A plurality of ring muscles arranged inside and outside multiplex,
An opening characterized in that diagonal reinforcements are integrally joined from the inner ring reinforcement to the outer ring reinforcement, and the diagonal reinforcements are arranged so as to extend in the tangential direction of the inner ring reinforcement. Reinforcement. 2. The four diagonal reinforcing bars are provided, and the inner ends of the four diagonal reinforcing bars are arranged at respective positions where the circumference of the inner ring reinforcing bar is divided into approximately four equal parts. Two adjacent diagonal reinforcements of the diagonal reinforcements are paired together.
2. The pair of pairs is arranged so that two diagonal reinforcing bars of each pair or extension lines thereof are arranged so as to extend in the tangential direction of an inner ring reinforcing bar that intersects with each other.
Opening reinforcement as described in.