JPH0396556A - Jointing mechanism for reinforcement - Google Patents

Abstract

PURPOSE:To shorten the joint lengths of clustered reinforcements by arranging female screws along a central axial line, at jointing end sections, and by connecting both the reinforcements to each other with the jointing bolt of strength higher than that of the reinforcements. CONSTITUTION:Along the central axial line from the jointed end surfaces of reinforcements 1a, 1b, female screws 2a, 2b are arranged to specified depths. In the meantime, a jointing bolt 3 is made of material with strength higher than that of the reinforcements. After that, the bolt 3 is spirally fitted on the female screws 2a, 2b of both the reinforcements to be connected to each other. As a result, the arrangement of the clustered reinforcements or the like can be rationalized.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a joint structure for reinforcing bars. (Conventional technology) When joining reinforcing bars in the past, joint structures using coupler joints and pressure welding are used. In addition to these single reinforcing bars, there are reinforcing bar base materials (at) (mu), (at') (mu') with small cross sections as shown in Figures 6 and 7.
, (a,) (a.) (a.), (at') (az'
l (A bundled reinforcing bar is used to bundle ax'l. (Intelligence M to be solved by the invention) In the above coupler joint and pressure welding joint, the cross-sectional area of the reinforcing bar at the joint part of the reinforcing bar becomes large, This is inconvenient when inserting reinforcing bars into precast members.

The bundled reinforcing bars are used by bundling reinforcing bars with small cross sections, so in the case of members with the same cross section, it is possible to have sufficient spacing between reinforcing bars compared to the case of normal reinforcement, and in this way, the spacing between reinforcing bars can be made larger. This improves concrete filling properties at column-beam joints, etc., and it also has excellent workability, such as easier fixing of reinforcing bars compared to large-diameter reinforcing bars that have the same cross-sectional area as bundled reinforcing bars. There is. Furthermore, the circumferential length of bundled reinforcing bars is larger than that of large-diameter reinforcing bars with the same cross-sectional area, which is advantageous in that it is effective in joints where bonding strength of reinforcing bars is a problem.

However, the stress transmission mechanism of reinforcing bars depends on the adhesion force between the reinforcing bars and concrete, so the overlapping length of the reinforcing bars becomes longer, or as shown in Figures 6 and 7, bundled reinforcing bars Reinforcing bars (b) were required to be placed across the joints of each of the reinforcing bars that make up the structure, and there were particular difficulties in arranging reinforcement for precast concrete members. In addition, in the cross section of the bundled reinforcing bars shown in Figure 6(a) and Figure 7(0), it is shown that stress is transmitted between the reinforcing bars filled in black. The present invention has been proposed in view of the problems of the prior art described above, and its purpose is to significantly reduce the length of the joint, suppress the increase in the cross section of the joint, and provide reinforcing bars with excellent workability. The point is that it provides a joint structure. (Means for Solving the Problems) In order to achieve the above object, the reinforcing bar joint structure according to the present invention consists of a pair of adjacent reinforcing bars in which a female screw hole is bored from the joint end surface along the central axis. A connecting bolt is screwed through each of the female threaded holes. (Function) The reinforcing bar joint structure according to the present invention does not require a joining member to be provided between the outer peripheries of the reinforcing bars to be joined, as in conventional reinforcing bar joint barrel construction, but within the reinforcing bars to be joined. By providing a female screw hole extending in the axial direction from the joint end surface and screwing a joint bolt through each female screw hole of a pair of adjacent reinforcing bars, the joint can be easily disconnected, like a reinforcing bar joint using a conventional coupler joint. The area will not increase. Further, the joint length l8 of the reinforcing bars at the reinforcing bar joints as shown in FIGS. 6 and 7 is designed by the following equation.

l, = σt : Perimeter of reinforcing bar τ. : Adhesive stress In the present invention, as described above, the reinforcing bar base material of the bundled reinforcing bars is joined by bolts screwed across the respective female threaded holes, and then the bundled reinforcing bars are formed. The joint length L0 is designed using the following formula. Lt= (1 (1*'・at' /61at)
・Re ・= (2) σt: Stress degree of bolt ag': Cross-sectional area of bolt Therefore, although the cross-sectional areas a and ' of the bolt in equation (2) are smaller, the allowable yield strength is higher than that of the reinforcing bar base material. By using bolts made of the same material, the joint length of the bundled reinforcing bars L. can be made extremely small. Also, depending on the position of the joint, LE can be set to zero. (Embodiments) The present invention will be described below with reference to illustrated embodiments.

(la) and (lb) are the reinforcing bar base materials to be joined, and female screw holes (2a) and (2b) extend from the joint end surface to the sleeve line direction, respectively.
is drilled.

Then, connecting bolts (3) having a higher strength than the base metals are screwed across the female screw holes (2a) and (2b) of both the reinforcing bar base materials (la) and (lb). la) (lb
) are joined so that their joint end faces abut, and then bundled into reinforcing bars.

In the figure (3a) is the male threaded part of the connecting bolt (3). The joint length of the bundled reinforcing bars constructed in this way becomes extremely small as explained in equation (2) above, and the advantages of the bundled reinforcing bars mentioned above can be utilized, and depending on the stress state of the reinforcing bars, additions may not be necessary. The left half of Fig. 4 shows an example in which the present invention is applied to the joining of reinforcing bars (4) and (5) of precast concrete member 0. A bolt (6) is hinged across the female threaded hole drilled across, and the reinforcing bars (4) and (5) are joined via the bolt (6) so that their protruding end surfaces abut each other. The right half of Figure 4 shows a coupler joint as a comparative example of the present invention, in which the precast concrete member (
The protruding ends of each reinforcing bar (4) and (5) in the field are cut into a cutter (7).
The cross-sectional area of the reinforcing bar joint becomes large, which is disadvantageous in terms of construction. In the figure, l' indicates the covering thickness. The left half of FIG. 5 shows an embodiment in which the present invention is applied to a fixing part of a reinforcing bar joint to a precast concrete member, such as a column base part where upper and lower column reinforcing bars of a precast concrete column are joined and fixed. ) The cross section of the grout part (8) between the joint part of (5) and the vicinity of the fixing hole is small. The right half of Fig. 5 shows the case of a coupler joint as a comparative example. 4) In (5), the reinforcement is biased toward the inner center of the cross section of the member than in the case of the present invention, which is disadvantageous structurally. (Effects of the Invention) As described above, in the reinforcing bar joining structure according to the present invention, a joining bolt having higher strength than reinforcing bars is inserted into a female screw hole drilled along the central axis from each joining end face of a pair of adjacent reinforcing bars. Since the reinforcing bars are screwed together and held together, the joint length of the reinforcing bars becomes extremely small, and depending on the stress state of the reinforcing bars, reinforcement bars become unnecessary.When the present invention is applied to bundled reinforcing bars, The strengths of the system are fully utilized. Furthermore, unlike conventional coupler joints, the cross-sectional area of the reinforcing bar joint does not increase, which is advantageous in construction, and also facilitates reinforcing in precast concrete members.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of a reinforcing bar joint structure according to the present invention, and FIGS. 2 and 3 are respectively shown in the direction of arrows ■-■ in FIG.
Figure 4 is a front view showing a case in which the reinforcing bar joint structure and the Cable joint of the present invention are applied to the reinforcing bars of a precast concrete member, and Fig. 5 is a front view showing the reinforcing bars embedded in a precast concrete member. FIG. 6 is a cross-sectional view showing a case where the reinforcing bar joining structure and coupler joint of the present invention are applied to the joint of reinforcing bars to be fixed (Alt(3) is a plan view and a cross-sectional view of bundled reinforcing bars, respectively; FIG. 7 Figure (At (B
+ is a plan view and a cross-sectional view showing other examples of bundled reinforcing bars, respectively. (la) (lb)... Reinforcing bar base material, (2a) (2b) - Female threaded hole, (3)... Bolt.

Claims (1)

[Claims] A connecting bolt having a higher strength than each reinforcing bar is screwed across each of the female threaded holes of a pair of adjacent reinforcing bars, each of which has a female threaded hole drilled from the joint end surface along the central axis. Rebar joint structure.