JPH0749697B2 - Reinforcing bar joint structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a joint structure of reticulated reinforcing bars formed by welding vertical and horizontal reinforcing bars.

(Prior Art) In the Japanese Patent Laid-Open No. 63-289156, the present inventors have welded longitudinal and lateral reinforcing bars and set the joint arrangement interval to be twice the remaining ordinary section reinforcement arrangement. A joint of reticulated reinforcing bars, which is obtained by polymerizing and welding a pair of reticulated reinforcing bars so that the joint rebars of one reticulated rebar are located in the middle of adjacent joint rebars of the other reticulated rebar, and In Japanese Laid-Open Patent Publication No. 63-304861, a pair of braided rebars in which longitudinal and lateral rebars are welded and the rebar spacing of the joint portion is twice as long as the rebar spacing of the remaining general portion are located on the same plane. Opposite, then each longitudinal and lateral reinforcing bars are attached, and connecting reinforcing bars having the same bar arrangement interval as the joint portion of each braided reinforcing bar are polymerized across the joint portions of both braided reinforcing bars, and each joint part is the same. Proposed a joint of reticulated reinforcing bars connected so that the reinforcing bars of the connecting reinforcing bar are located in the middle of the To increase the bearing capacity area of the concrete in the joint portion of the muscle, and the like can be effectively prevented Bearing splitting of the concrete.

(Problems to be solved by the invention) However, vertical and horizontal reinforcing bars (a), (b), (a '), (b')
In the joint portion of the adjacent reticulated reinforcements (A) (A ') formed by double-arranging the inner and outer reticulated reinforcements welded to each other, the transverse reinforcements (b) (b) (b) of the opposing reticulated reinforcements (A) (A') When a tensile force T acts on ′ ′, both rebars (b) and (b ′) are eccentrically positioned, so that when the eccentric distance of the horizontal rebar is e, an eccentric moment M of e · T is generated.

(Refer to Fig. 14) This is not a problem for small diameter braided rebars with a diameter of 10 mm or less, but it is a problem if it occurs in welded braided rebars that use large diameter rebars. Also causes stress, causing the rebar to break before yielding.

(Means for Solving Problems) The present invention has been proposed in order to solve such problems, and is a reticulated reinforcing bar having double inner and outer reticulated reinforcing bar welded longitudinally and laterally. In the transverse lap joint part, straddling between the transverse rebars of the reticulated reinforcing bars that overlap in a face-to-face relationship, resisting the tensile force of concrete caused by the eccentric moment generated by the tensile stress acting on the transverse rebars, and The present invention relates to a joint structure of reticulated reinforcing bars, which is characterized by comprising tensile reinforcing bars and supporting pressure splitting prevention lateral joint reinforcing bars that prevent the bearing splitting fracture of concrete by vertical reinforcing bars intersecting with horizontal reinforcing bars. .

(Operation) Since the present invention is configured as described above, when a tensile force acts on the horizontal reinforcing bars in the joint portion of the inner and outer reticulated reinforcing bars, the concrete generated by the eccentric bending moment resulting from the misalignment of the respective horizontal reinforcing bars Tensile stress, while restrained by the transverse joint reinforcing bar arranged across the horizontal reinforcing bars of the inner and outer reticulated reinforcing bars that polymerize in the facing,
The joint reinforcing bar prevents the splitting fracture of concrete due to the vertical reinforcing bar crossing the horizontal reinforcing bar in the reticulated reinforcing bar, so that the stress can be smoothly transmitted between the reticulated reinforcing bars in the joint section.

(Examples) The present invention will be described below with reference to illustrated examples.

Figures 1 to 3A and 3B show vertical and horizontal reinforcing bars (1) (2)
(1 ') and (2') are welded, and the rebar spacing of the joint is double the rebar spacing l of the general part (= 2l). A) and (A ′) are positioned such that the vertical reinforcing bar (1) of the joint portion of one reticulated reinforcing bar (A) is located in the middle of the adjacent vertical reinforcing bar (1 ′) of the other reticulated reinforcing bar (A ′). An example in which the present invention is applied to the joint portion of the reticulated reinforcing bar shown in Japanese Patent Laid-Open No. 63-289156, which is superposed and connected as described above, is shown at the outer end of the joint section.
A lateral joint reinforcing bar (3) straddling each horizontal reinforcing bar (2) (2 ') of (A') is arranged.

Since the illustrated embodiment is constructed as described above,
As shown in Fig. 3C, when tensile force acts on the horizontal rebars (2) and (2 '), the eccentric moment M =
e · T (e: eccentricity amount) is generated, and the tensile stress T is generated in the concrete due to this moment, and the concrete tends to be cracked. According to the present embodiment, the tensile force generated in the concrete due to the eccentric moment is The lateral joint reinforcing bars (3) restrain the concrete, prevent cracking of the concrete, and allow smooth transmission of stress between the braided bars (A) (A ').

Further, as shown in FIG. 3D, when the concrete cross section surrounded by the adjacent vertical reinforcing bars (1) and (1 ') is small and there is a high possibility that the concrete will cause bearing pressure splitting, the transverse joint reinforcing bar (3 ), The above-mentioned bearing split fracture of concrete is prevented.

In the above embodiment, the lateral joint reinforcing bar (3) is concentrated at the outermost end of the joint portion of the reticulated reinforcing bars (A) and (A '), and the joint portion has proof strength and deformation performance. This is also sufficient, but as shown in FIG. 4, the longitudinal and transverse rebars (1) of each braided bar on the front of the joint
In the case of (2), (1 ') and (2') arranged between all the intersections, the joint strength and deformation performance are further improved.

FIG. 5 and FIG. 6 show the reticulated reinforcing bars (A) and (A ′) in each of the above-mentioned embodiments which are arranged so as to be located on the same plane.
Reinforcing bars (B) having welded longitudinal and lateral reinforcing bars (1 ″) (2 ″) and having the same rebar spacing as the joint portion of the reticulated reinforcing bars (A) and (A ′) are both reticulated reinforcing bars (A). The present invention is applied to the joint portion of the reticulated reinforcement shown in the above-mentioned JP-A-63-304861 in which the joint portion of (A ') is superposed and located in the middle of each joint portion. An example is shown, in which the horizontal reinforcing bars (2) (2 ') and the additional reinforcing bars (B) of the reticulated reinforcing bars (A) and (A') are attached to both outer ends of the joints of the reticulated reinforcing bars (A) and (A '). A horizontal joint reinforcing bar (3) straddling (2 ″) is arranged on the horizontal reinforcing bar.

The operation and effect of this embodiment are substantially the same as those of the above-mentioned embodiment, so that the description thereof will be omitted.

Further, FIG. 7 shows an embodiment in which the lateral joint reinforcing bar (3) is arranged between the intersections of the vertical and horizontal reinforcing bars (1 ″) (2 ″) of the added reinforcing bar (B) in the joint portion.

It should be noted that, in the above-mentioned embodiment, the case where the braided reinforcing bars are joined to each other in the joint portion facing each other is shown, but the present invention is also applied to the case where they are joined back to back. Shows the embodiment, and the same reference numerals are attached to the equivalent parts in the drawing.

The present invention is also applicable to a joint of reticulated reinforcing bars in which reticulated reinforcing bars having a normal spacing between rebars are doubled.

Next, examples of the present invention will be given. As shown in FIGS. 12 and 13, in order to examine the joint properties using a large diameter welded wire mesh of D38, an experiment was conducted in which both reinforcing bars at both ends of the test body were pulled.

As shown in Fig. 12, the test piece has lateral joint reinforcement bars concentrated on the outermost end of the joint, and as shown in Fig. 13, lateral joint reinforcement is provided at the intersection of the outermost end and each welding point. Three specimens were compared, one with the arrangement of the muscles and one without the transverse joint reinforcement. The yield strength and deformation performance of the joint are as shown in Fig. 12, and even if the transverse joint reinforcing bar is arranged only at the outermost end, the yield strength and deformation are sufficient as the joint performance,
Furthermore, the one in which the transverse joint reinforcing bar is arranged at each welding point has excellent yield strength and deformation performance. However, those without the transverse joint reinforcing bar were broken before the load at which the reinforcing bar yielded, and exhibited properties inferior to those with the transverse joint reinforcing bar arranged.

The specifications of the test bodies shown in FIGS. 12 and 13 are shown in Tables 1 and 2 below.

(Effect of the invention) As described above, according to the present invention, in the joint portion of the reticulated reinforcing bar in which the reticulated reinforcing bar material obtained by welding the longitudinal and lateral reinforcing bars is double-laid, the reticulated reinforcing bar to be connected is laid across each transverse reinforcing bar. By arranging the horizontal joint reinforcing bar, even if the eccentric bending moment acts due to the misalignment of the horizontal bar of the braided bar,
Restrain the force generated in the joint part due to the same bending moment,
The purpose of the present invention is to smoothly transmit the stress between the reticulated reinforcing bars in the joint portion, prevent the concrete from breaking at the joint portion, and significantly improve the joint strength and the deformation performance.

The lateral joint reinforcing bar can prevent the bearing pressure splitting of concrete in the joint portion.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a joint structure of reticulated reinforcing bars according to the present invention, FIG. 2 is a transverse plan view thereof, FIGS. 3A and 3B.
The drawing is a view taken along the line III-III in FIG. 2, and FIGS. 3C and 3D are explanatory views of the operation of the embodiment. FIG. 4 is a cross-sectional plan view showing another embodiment of the present invention, FIGS. 5 and 6 are partial oblique views showing the other embodiment of the present invention, and FIG. 7 is a cross-sectional plan view showing the same. FIG. 8 is a cross-sectional plan view showing still another embodiment of the present invention, FIG. 8 is a cross-sectional plan view showing still another embodiment of the present invention, FIG. 9 is its front view, and FIG. 10 is an arrow X- of FIG. FIG. X, FIG. 11 are charts showing the test results of the joint performance of the present invention, FIG. 12A and FIG.
Figure 2B along with Figure 12C is a side view and a plan view of the test piece used in the test, respectively, along with a longitudinal section, Figures 13A and 13B along with Figure 13C is a side view showing another test piece. FIG. 14 is an explanatory view showing a state of action of a bending moment on a joint of a conventional braided reinforcing bar, as well as a plan view and a longitudinal sectional view. (A) (A ') ... braided rebar, (B) ... rebar (1) (1') (1 ") ... vertical rebar (2) (2 ') (2") ... horizontal rebar ( 3) ... Horizontal joint reinforcement

Claims (1)

[Claims] 1. A horizontal lap joint portion of a reticulated reinforcing bar having double-arranged inner and outer reticulated reinforcing bar materials formed by welding longitudinal and lateral reinforcing bars, straddling each of the transverse reinforcing bars of the reticulated reinforcing bar which overlaps each other, A tensile rebar-supporting pressure splitting prevention lateral that resists the tensile force of concrete caused by the eccentric moment generated by the tensile stress acting on the horizontal rebar and prevents the bearing splitting fracture of the concrete by the vertical rebar intersecting with the horizontal rebar. A joint structure of reticulated reinforcing bars, characterized in that directional joint reinforcing bars are arranged.