JPH073942A - Reinforcement cage - Google Patents

Abstract

PURPOSE:To attain labor saving in a manufacturing process and the like by arranging a decided quantity of shearing reinforcement only on the part position except the joint part position on the end parts of respective main reinforcement constituting a main reinforcement group, and intensively arranging the shearing reinforcement so that an arranged quantity of reinforcement near the joint part position is denser than that on the other part position. CONSTITUTION:A reinforcement cage is composed of a main reinforcement group consisting of four pieces of same length main reinforcement 1 and shearing reinforcement 2, 2-a arranged so as to circumscribe and surround the main reinforcement group. The shearing reinforcement 2, 2-a are arranged on the part position circumscribing the main reinforcement group except the joint part position 3 on the end parts of the main reinforcement 1. In this case, the reinforcement 2-a arranged near the joint part position 3 are intensively arranged so as to be larger in density of a reinforcement arranging quantity per unit length in the axial direction of the main reinforcement than the reinforcement 2 arranged on the other part position. Hereby it is unnecessary at manufacturing the reinforcement cage, to displace shearing reinforcement which should be arranged in a joint part position from that position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing bar cage used in a cast-in-place concrete construction method, and is characterized by the arrangement method of its shear reinforcing bars.

[0002]

[Background Art] When constructing a framework of a building frame by a cast-in-place concrete method, first, a framework of the required structure is constructed, then a form is assembled and concrete is placed. It has been constructed by. Recently, construction of reinforcing rod cages such as pillars and beams that have been manufactured in advance at another factory (referred to as pre-assembled reinforcing rod cages), and these are joined to each other on site to construct a framework reinforcing rod structure. The law is becoming widespread. This construction method is referred to as the pre-assembled rebar cage method.

Here, the rebar cage refers to a group of four or more main rebars, which is a main axis of a frame rebar structure constituting a frame of a building body, for one rebar group. It is a basket-shaped body formed by wrapping the shear reinforcing bars in an arrangement such that they are circumscribed and lateral to the axis of the main reinforcing bar. This shear reinforcement is referred to as the bar or hoop in the case of columns and the stirrup or stirrup in the case of beams. The amount of bar arrangement and the layout method are stipulated by the Building Standards Act and other public or quasi-public standards. According to these standards, a predetermined amount of reinforcing bars should be arranged in such a manner that they are substantially equally spaced over the entire length of the main reinforcing bar group.

Regarding this pre-assembled rebar cage, the corresponding main rebars are joined in a butt shape at the loading site to join the rebar cages. However, as a butt joint means for the main rebars, a screw joint or the like is used. Mechanical joint hardware is used. In the prior art, when joining with the above-mentioned mechanical joint hardware, the shear reinforcing bar is not arranged in advance in the region of the area corresponding to the insertion length from the end of the main rebar into the joint metal fitting at the end of the main rebar. The part must be left blank.

This state will be described with reference to FIG. Figure 2
In (a), a rebar cage consisting of a set of four main rebars 1 is shown. In FIG. 2, the lower end of each main reinforcing bar is shown joined to the main reinforcing bar 1-a of the lower reinforcing bar cage by the mechanical joint metal fitting 4, and the upper end of the main reinforcing bar is connected to the main reinforcing bar of the upper reinforcing bar cage by the mechanical reinforcement. The state in which they are to be joined by the type fitting hardware is shown. At this time, the upper end of the main reinforcing bar is a joining portion 3 which is a portion having a length to be inserted into the mechanical joint metal fitting.
The shear reinforcements are not placed in (the area surrounded by the dotted line in the figure), and the shear reinforcements that should be placed on the outer periphery of the joint hardware group in the final process of construction, that is, the above-mentioned joints Shear reinforcement 2-b to be placed in
At this point, (in this figure) is shown biased toward the center of the main rebar axis, avoiding the joint. In addition,
In this rebar cage, the above-mentioned joining parts are originally located at two places, the upper end and the lower end, but the lower end of them is shown with the fitting hardware attached.

After the main rebar ends are joined to other rebar cage main rebars by mechanical joint metal fittings, the shear reinforcing bar 2-b which has been offset is moved to the joint metal fitting 3 to move the joint metal fitting group. Place it on the outer circumference of. As a result, a predetermined amount of shear reinforcing bars are arranged over the entire length of the main reinforcing bars of the reinforcing bar cage. In addition, as shown in FIG. 2B, the shear reinforcing bar 2 arranged on the outer circumference of the main reinforcing bar group and the shear reinforcing bar 2-b arranged on the outer circumference of the joint hardware group have different loop sizes (the latter is better). Larger than the former).

As described above, according to the prior art, when manufacturing the pre-assembled rebar cage, the shear reinforcing bars to be arranged are offset toward the center of the main rebars, and after the main rebars are joined together,
Work is being performed to move this to the outer periphery of the joint metal piece and to arrange it again. Such work is extremely complicated, and the advantage of simplification of on-site work, which the pre-assembled rebar cage method originally should have, is greatly impaired. Moreover, since the outer diameter of the mechanical joint metal fitting is considerably thicker than the diameter of the main reinforcing bar, the loop diameter of the shear reinforcing bar arranged on the outer periphery of the joint metal fitting group is the loop diameter of the shear reinforcing bar arranged on the outer periphery of the main reinforcing bar group. There is a problem in that shear reinforcements having different loop diameters must be prepared because they must be considerably larger. The present invention is intended to solve the problems in the conventional pre-assembled rebar cage construction method.

[0008]

DISCLOSURE OF THE INVENTION The present invention is a rebar cage used in a cast-in-place concrete construction method, which comprises a group of four or more main rebars constituting a frame of a building body and a set of main rebars. In a rebar cage consisting of a shear reinforcing bar arranged so as to circumscribe the main rebar group and surround this group, only the part excluding the joint part located at the end of each main rebar forming the main rebar group In addition, a predetermined amount of shear reinforcement is arranged, and in the arrangement method, the shear reinforcement is collectively arranged so that the amount of reinforcement in the vicinity of the joint is denser than the amount of reinforcement in other parts. The present invention provides a rebar cage used in a cast-in-place concrete construction method, which is characterized by the following method.

The reinforcing bar cage according to the present invention will be described with reference to FIGS. The rebar cage in the figure is 4
The book is composed of a main rebar group consisting of main rebars 1 having the same length and a shear reinforcing bar (2 or 2-a) arranged so as to circumscribe and surround the main rebar group. This reinforcing bar is arranged at the main rebar group circumscribing part excluding the joint part 3 at the end of the main rebar (the part surrounded by the dotted line in the figure).
Then, the shear reinforcing bars (referred to as aggregated shear reinforcing bars) 2-a that are densely arranged in a part close to the joint part 3 have a narrower arrangement interval than the shear reinforcing bars 2 arranged in other parts, That is, they are collectively arranged so that the density of the reinforcing bar per unit length in the axial direction of the main reinforcing bar is large.

The butt joint means used in the rebar cage of the present invention is not specified. For example, in the case of a mechanical joint metal fitting, a screw joint, a mortar joint, a coupler joint, a screw joint, and a composite joint thereof (for example, a screw mortar joint) can be applied. Besides, joining by welding can also be applied.

In the rebar cage of the present invention, the term "joint site" means that when a mechanical joint metal fitting is used for joining, the main rebar end to the open end of the joint metal fitting (from this open end to the predetermined insertion length within the joint) It will be inserted in) until the part. Further, when joining by welding, it means a portion that extends a required distance in the axial direction from the end of the main reinforcing bar. This distance is a distance for securing a space for welding work, and is generally about 30 cm although various variations are observed depending on the diameter of the main reinforcing bar, the welding method, and the like.

[0012] The amount of reinforcement of the shear reinforcements arranged in the main rebar group excluding the joints is the same as that in the case of arranging over the entire length of the main rebar group in the prior art, that is, calculated by design as a rebar cage. It is the same as the amount of reinforcement. Further, the collective arrangement in the reinforcing bar cage of the present invention means the arrangement so that the arrangement density of the shear reinforcing bar per unit length in the axial direction of the main reinforcing bar is higher than that in the area other than the integrated arrangement area. That is, when the diameters of the shear reinforcing bars are the same throughout the entire rebar cage, the arrangement interval is narrowed to achieve the collective arrangement, and the diameters of the shear reinforcing bars to be arranged collectively are reinforced by arranging them in other parts. When the diameter is larger than the diameter of the muscle, the collective arrangement can be achieved even with the same arrangement interval. The amount of the reinforcing bars to be collectively arranged is almost the same as the amount of the shear reinforcing bar to be originally arranged at the joining portion in the conventional technique, and the amount of the shear reinforcing bar of the entire reinforcing bar cage is the same as that in the conventional technique.

The shear reinforcing bar is a usual shear reinforcing bar, and flat steel or the like can be used in addition to the reinforcing bar. Further, the method for arranging the shear reinforcing bar is not particularly specified. For example, there are a spiral winding method, a stepwise arrangement method as shown in FIG. 1, and a plowing arrangement method.

In the rebar cage of the present invention, unlike the prior art, it is not necessary to move the shear reinforcing bars that have been offset to one another after being joined with another rebar cage. Therefore, when the reinforced concrete clad is completed, the shear reinforcement is not arranged at the joint, but the mechanical properties of the clad are different from those of the conventional structure where the shear reinforcement is arranged at this part. There is no. Such effects in the present invention were unpredictable. Although the rebar cage of the present invention can be manufactured separately, it is also possible to construct the rebar cage of the present invention by joining the main rebar to the lower rebar cage at the construction site to form the upper rebar cage. .

[0015]

The construction of the reinforced cage according to the present invention and the reinforced concrete slab using the same has the following advantages over the conventional construction of the reinforced cage based on the shear reinforcing bar arrangement method and the construction of the reinforced concrete slab using the same.

(1) When manufacturing a rebar cage, it is not necessary to offset the shear reinforcing bar to be arranged at the joint part so as to avoid this part, thus saving labor in the manufacturing process. further,
Since the process of moving the shear reinforcing bars that have been offset to one another after joining the rebar cages is also unnecessary, labor saving on-site work can be achieved.

(2) When the reinforcing bar cage is joined by a mechanical joint metal fitting, in the prior art, as shown in FIG. 2- (b), the shear reinforcing bar arranged on the outer circumference of the joint metal fitting and the main reinforcing bar group are arranged on the outer circumference. Since the loop size of the shear reinforcing bar to be used is different, the shear reinforcing bar having a different loop size must be prepared when manufacturing the reinforcing bar cage, which complicates the manufacturing process, but this complexity is eliminated.

(3) When a mechanical joint metal fitting is used as the joining means, a shear reinforcing bar is conventionally arranged also on the outer periphery of the metal fitting group. Therefore, the size of the cross section of the concrete member is the size of the outer circumference of this shear reinforcement bar plus the required cover thickness, while the shear reinforcement bar is not placed on the outer circumference of the joint group and Since the diameter is generally smaller than the difference between the joint radius and the main rebar radius, the loop diameter of the shear reinforcing bar arranged on the outer periphery of the main rebar group is smaller than the loop diameter of the joint group itself. Therefore, the size of the member cross section is limited to the size obtained by adding the required cover thickness to the joint group loop, and the reduction of the member cross section size can be achieved. This effect is shown in FIG. FIG. 3A shows a cross section of the concrete member 5 when the conventional rebar cage is used, and FIG. 3B shows a member cross section when the rebar cage of the present invention is used. In either case, a cover concrete having a predetermined thickness h must be provided from the outer edge of the shear reinforcing bar forming the outermost circumference of the reinforcing bar cage to the outside, as shown in FIGS. 2 (b) and 3 (a). As described above, the loop size of the shear reinforcing bar 2-b arranged on the outer periphery of the joint hardware group is the shear reinforcing bar 2-a arranged on the outer periphery of the main reinforcing bar group.
Since it is larger than the loop size shown in FIG. 3B, the member cross-sectional size is smaller when the reinforcing bar cage of the present invention is used by the difference. Note that in FIG.
The cross section of the member of (a) is shown by filling it with a dotted line.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention, in which FIG. 1 (a) is an elevational view and FIG. 1 (b) is a plan view.

2A and 2B are views showing a reinforcing bar cage in the related art, wherein FIG. 2A is an elevation view and FIG. 2B is a plan view of a shear reinforcing bar.

FIG. 3 is a cross-sectional view of a concrete member, FIG. 3 (a) is a cross-sectional view showing a case where a conventional reinforcing bar cage is used, and FIG. 3 (b) is a sectional view showing a case using the reinforcing bar cage of the present invention. FIG.

[Explanation of symbols]

1 Main Reinforcing Bar 1-a Main Reinforcing Bar of Other Reinforcing Bar Baskets 2 Shear Reinforcing Bars 2-a Aggregate Shear Reinforcing Bars 2-b Mechanical Reinforcing Bars Arranged on the Outer Perimeter of the Hardware Group 3 Joints (parts surrounded by dotted lines) 4 Mechanical joint hardware 5 Concrete member h Cover thickness

Claims (1)

[Claims] 1. A rebar cage used in a cast-in-place concrete construction method, comprising a group of four or more main rebars and a set of main rebars constituting a frame of a building body. In a rebar cage consisting of a shear reinforcing bar arranged so as to circumscribe this group, a predetermined amount is applied only to the part excluding the joint part located at the end of each main bar that constitutes the main bar group. The shear reinforcements are arranged and the shear reinforcements are collectively arranged so that the amount of reinforcement in the vicinity of the joint is denser than the amount of reinforcement in other parts in the arrangement method. Reinforcing bar basket used for the cast-in-place concrete method.