JPH0444048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reinforcement structure for RC columns using X-shaped reinforcement.

[Conventional technology]

As shown in Figures 7 and 8, the reinforcement structure of an RC column using X-type reinforcement is as follows: between the vertical column main reinforcements 1 at the four corners, there are vertical reinforcement sections 2 corresponding to the column and beam joints 3.
The bent column main reinforcement 2, which consists of the upper diagonal reinforcement 2b and the lower diagonal reinforcement 2c that are bent diagonally from above and below the vertical reinforcement portion 2a, is arranged so as to have an X shape in side view, and It is already known that a hoop muscle 7 is wrapped around a main muscle 1 group.

[Problem that the invention seeks to solve]

The X-shaped reinforcement method has more than twice the energy absorption capacity compared to the normal reinforcement method, which mainly uses vertical and horizontal reinforcement, and has dramatically improved toughness resistance, and can withstand alternating horizontal loads during earthquakes. It has been experimentally confirmed that it is effective in preventing shear failure of columns and walls that are subject to damage. However, the conventional reinforcement structure has the following problems.

(1) Since the vertically adjacent bent column main reinforcements 2 are joined by gas pressure welding, the bending point between the vertical reinforcement portion 2a and the lower diagonal reinforcement 2c (position P in the figure) will shrink due to the pressure welding. It moves downward, making it difficult to obtain construction accuracy. In addition, if there is poor accuracy, it is impossible to correct the reinforcement arrangement.

(2) In the X-type reinforcement arrangement, the anchorage length of the diagonal reinforcement to the concrete of the column-beam joint section 3 cannot be longer than the length of the vertical reinforcement section 2a.
When using steel rods with high tensile strength such as threaded reinforcing bars, the vertical reinforcement portion 2a may pull out (slip in the vertical direction against the concrete at the joints of columns and beams), reducing the inherent strength of the X-shaped reinforcement arrangement. there's a possibility that.

(3) When the vertical column main reinforcements 1 at the four corners and the bent column main reinforcements 2 arranged in an X-shape between them are pre-assembled, they cannot be joined by gas pressure welding, etc., and workability is improved by pre-assembly. It is difficult to do so.

An object of the present invention is to solve these problems.

[Means for solving problems]

Technical measures taken by the present invention to solve the above problems are as follows.

That is, the present invention provides a folded structure between the vertical column main reinforcements at the four corners, which consists of a vertical reinforcement section corresponding to the column-beam joint, and an upper diagonal reinforcement and a lower diagonal reinforcement that are bent obliquely from both ends of the vertical reinforcement section. In an RC column reinforcement structure in which curved column main reinforcements are arranged in an X-shape in side view and hoop reinforcements are wrapped around the vertical column main reinforcement group, the vertical column main reinforcements and bent column main reinforcements are arranged. Threaded reinforcing bars are installed in the vertical center of the column and beam joints.
A column reinforcement fixing plate is provided which is formed into a rectangular ring shape in plan view and has a horizontal pressure receiving surface, and the vertical column main reinforcement and the vertical column part of the bent column main reinforcement are formed on the column reinforcement fixing plate. The columnar reinforcement fixing plate is fixed to the columnar reinforcement plate by each pair of nuts that are inserted into the through holes and screwed into threaded joints of the threaded reinforcing bars, with the columnar reinforcement fixing plate being sandwiched from both upper and lower sides by the nuts. It is a feature.

[Effect]

According to the above configuration, the vertical column main reinforcement and the vertical column main reinforcement part of the bent column main reinforcement are attached to the column reinforcement fixing plate having a horizontal pressure-receiving surface, and the column reinforcement fixing plate is attached from both upper and lower sides using each pair of nuts. Since they are fixed in a sandwiched state, the column main reinforcements, especially the vertical reinforcement portions of the bent column main reinforcements, are completely prevented from slipping against the concrete at the column and beam joints.

Even if the vertical column main reinforcements at the four corners and the bent column main reinforcement arranged in an X-shape between them are pre-assembled via the column reinforcement fixing plate and nuts, when the nuts are loosened, the Since it is possible to move the main reinforcement of each column in any direction independently of each other, it is possible to use a lock nut type mechanical joint as a means of joining diagonal reinforcement, which improves the accuracy of reinforcement arrangement and construction accuracy. is possible.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Figures 1 and 2 are a front view and a plan view of the reinforcement structure of an RC column using X-shaped reinforcement, Figure 3 is a perspective view of the main part, Figure 4 is a side view of the main part, Figures 5A, 5B and 5C are front views showing the construction method.

1... is the vertical column main reinforcement placed at the four corners, 2...
are bent column main reinforcements arranged in an X-shape between the vertical column main reinforcements 1..., these 1..., 2...
...are threaded reinforcing bars (deformed reinforcing bars with screw-shaped ribs that increase adhesion to concrete)
It uses The vertical column main reinforcements 1, 1 which are vertically adjacent to each other are connected to a so-called lock nut type mechanical joint 4 consisting of a female threaded sleeve 4a and a pair of lock nuts 4b, 4b, at a position approximately 1 m above the column/beam joint 3. are joined together. Each bent column main reinforcement 2 includes a vertical reinforcement portion 2a having a length equal to the vertical width l of the column-beam joint portion 3, an upper diagonal reinforcement 2b and a lower diagonal reinforcement 2c that are bent diagonally from both ends of the vertical reinforcement portion 2a. The overall vertical length is the same as that of the vertical column main reinforcement 1. The vertically adjacent bent column main reinforcements 2, 2 are also joined by a lock nut type mechanical joint 4 at a position approximately 1 m higher than the column/beam joint 3.

A column reinforcement fixing plate 5 having an annular shape in a plan view and having a horizontal pressure-receiving surface S is provided at the vertical center of the column-beam joint portion 3 . The column reinforcement fixing plate 5 has a through hole (blind hole) 5a slightly larger than the diameter of the vertical column main reinforcement 1 and the bent column main reinforcement 2.
are formed in a predetermined number, and the vertical column main reinforcements 1 and the vertical column portions 2a of the bent column main reinforcements 2 are inserted through these through holes 5a. Then, each pair of nuts 6 are screwed into threaded joints of the vertical column main reinforcement 1 and the bent column main reinforcement 2.
a, 6b, vertical column main reinforcement 1 and bent column main reinforcement 2
to the columnar reinforcement fixing plate 5, and the nut 6
The columnar reinforcement fixing plate 5 is held and fixed from both upper and lower sides by a and 6b.

A hoop reinforcement 7 made of a spiral reinforcement is wrapped around the group of vertical column main reinforcements 1 and fixed with a binding wire or the like.

Reference numeral 8 denotes a beam reinforcing bar consisting of beam main reinforcing bars 9 made of threaded reinforcing bars, and a spiral stirrup 10 wrapped around them and fixed by means of bundling, welding, or the like. The beam main reinforcements 9 at the upper end are held at a predetermined height position by beam support members 11 installed between the vertical column main reinforcements 1 at the four corners. Each of the illustrated beam receiving members 11 is formed of an angle material, and its horizontal plate portion has blank holes 11a for inserting the vertical reinforcement portions 2a of the vertical column main reinforcements 1... and the bent column main reinforcements 2... ... are formed, and a recess 11b ... is formed at the upper edge of the vertical plate portion to fit with the beam main reinforcement 9 ... at the upper end. The beam support member 11 is supported by nuts 12 screwed onto the vertical column main reinforcements 1 at the four corners, and the vertical column main reinforcements 1... and the bent column main reinforcements 2...
It is not fixed to... This is done in consideration of not interfering with the free movement of the vertical column main reinforcements 1 and the bent column main reinforcements 2 during reinforcement work.
13 is column concrete, 14 is beam concrete,
15 shows the shear wall concrete, and 16 shows the wall reinforcement.
5b is a reinforcing rib for increasing the rigidity of the columnar reinforcement fixing plate 5.

According to the above-mentioned reinforcement arrangement structure, the vertical reinforcement portions 2a of the vertical column main reinforcement 1 and the bent column main reinforcement 2 are attached to the column reinforcement fixing plate 5 having the horizontal pressure receiving surface S, and each pair of nuts that sandwich the plate 5 are attached. 6a and 6b, in the event of an earthquake, the column main reinforcements (vertical column main reinforcement 1 and vertical reinforcement part 2) on both the left and right sides of the column-beam joint 3
Even if tensile forces in opposite directions are applied repeatedly to a), the concrete bearing pressure provided by the column reinforcement fixing plate 5 prevents the column main reinforcement from slipping against the concrete of the column-beam joint 3, and the X-shaped arrangement is maintained. The inherent strength of the muscles does not decrease.

Next, the construction method of the above reinforcement structure is shown in Figure 5 A.
The explanation will be based on B and C.

First, as shown in Fig. 5A, a reinforcing bar assembly unit A consisting of beam reinforcing bars 8 and column reinforcing bars 17 is assembled,
Lift it up with a retskar etc. The column reinforcing bars 17 are comprised of the vertical column main reinforcements 1..., the bent column main reinforcements 2..., the column reinforcement fixing plates 5, the hoop reinforcements 7, the beam receiving members 11..., and the like.

The beam reinforcing bars 8 and the column reinforcing bars 17 may be manufactured in advance, but the beam main reinforcing bars 9... and the stirrups 10
When these are fixed by welding, it is desirable to first manufacture the beam reinforcing bars 8 and then incorporate the column reinforcing bars 17 into the reinforcing bars 17 to form the reinforcing bar assembly unit A, as described below.

First, after making the beam reinforcing bars 8, the upper and lower beam main bars 9, 9
A column reinforcement fixing plate 5 is arranged between them, and a vertical column main reinforcement 1 is placed in the through hole 5a of the column reinforcement fixing plate 5.
Then, insert the bent column main reinforcing bars 2, and slightly loosen each pair of nuts 6a and 6b screwed into them. In other words, the vertical column main reinforcement 1 and the bent column main reinforcement 2 are integrally connected via the column reinforcement fixing plate 5 and the nuts 6a and 6b.
Moreover, the gap between the nuts 6a and 6b and the through hole 5a
Each of the vertical column main reinforcements 1 and the bent column main reinforcements 2 are connected so as to be movable independently of each other in both the vertical and horizontal directions within the range of the accommodating gap. Then, the spiral hoop reinforcements 7 in a reduced state are fitted around the vertical column main reinforcements 1... and suspended from the column reinforcement fixing plate 5 with wires or the like.

In addition, with the nuts 12 screwed into the predetermined positions of each vertical column main reinforcement 1,
Insert the vertical reinforcement portions 2a of the vertical column main reinforcement 1 and the bent column main reinforcement 2 into ..., and attach the beam receiving member 11 to the nut 1.
2 to support. The sleeve 4a and lock nut 4b forming the mechanical joint 4 are also screwed onto the ends of the vertical column main reinforcement 1 and the bent column main reinforcement 2 at appropriate times.

After the reinforcing bar pre-assembled unit A is assembled in this way, a suspension wire is hung around the beam reinforcing bars 8, and the reinforcing bar pre-assembled unit A is lifted up. In this state, the main beam reinforcements 9 at the lower end are the column reinforcement fixing plates 5.
It is in contact with the bottom surface of. Further, displacement of the beam reinforcing bars 8 in the beam main reinforcing direction with respect to the column reinforcing bars 17 is prevented by the contact between the spiral stirrup 10 and the column reinforcing plates 5, the vertical column main reinforcing bars 1, etc.

Next, with the reinforcing bar pre-assembly unit A suspended and supported, as shown in FIG. It is connected in this order to the main reinforcing bars 1, the bent column main reinforcing bars 2, the vertical column main reinforcing bars 1 and the bending column main reinforcing bars 2, etc. on the lower floor that were previously constructed, using lock-nut type mechanical joints 4. In this case, nuts 6a, 6b
are loosened, and the vertical column main reinforcements 1 and bent column main reinforcements 2 can freely move within a certain range, so the threads of the column main reinforcements to be joined can be aligned in phase, and the connection by the sleeve 4a and the lock nuts 4b, 4b can be performed. It can be done without any problems.

Thereafter, as shown in FIG. 5C, the spiral hoop reinforcements 7 are stretched and fixed to the vertical column main reinforcements 1 with binding wires or the like.

Then, the verticality of the vertical column main reinforcement 1, the vertical reinforcement part 2a of the bent column main reinforcement 2, and the upper and lower diagonal reinforcement 2
After correcting the positional relationship between the bending points 6a and 2c with respect to the column-beam joint 3, each nut 6a and 6b is tightened to complete the reinforcement work for the column. Note that the beam reinforcing bars 8 are vertical column main reinforcements 1... and bent column main reinforcements 2...
Preferably, after the hoop reinforcements 7 are fixed, they are lowered to their original beam reinforcing positions, and the upper main beam reinforcements 9 are supported by the beam support members 11.

In the above example, since the building has a rigid frame structure in one direction and a shear wall structure in the direction perpendicular to this, the bent column main reinforcement 2 is made planar (flat in the beam direction) as shown in the figure. The reinforcement is arranged to form an X shape, but if the building has a rigid frame structure in both directions, the reinforcement should be arranged to form a three-dimensional X shape, as shown in Figure 6. . Also, although not shown, if the vertical column main bars 1... are joined together using a lock nut type mechanical joint 4, the reinforcing bar front assembly unit A can stand on its own, so the bent column main bars 2... can be joined by bending Column main reinforcement 2... may be made longer by the amount of overlap, and may be simply an overlap joint.

〔Effect of the invention〕

The effects of the present invention are as follows.

The vertical reinforcement parts of the vertical column main reinforcement and the bent column main reinforcement are fixed to the column reinforcement fixing plate with a horizontal pressure-receiving surface using a pair of nuts 6a and 6b that sandwich the plate, so that the column Even if tensile forces in opposite directions are applied repeatedly to the column reinforcements (vertical column reinforcement 1 and vertical reinforcement portion 2a) on both the left and right sides of the beam joint, the concrete bearing pressure by the column reinforcement fixing plate will cause the column and beam to The main reinforcement of the column is prevented from slipping against the concrete at the joint, and the inherent strength of the X-shaped reinforcement does not decrease.

Even if the vertical column main reinforcements at the four corners and the bent column main reinforcements arranged in an X-shape between them are pre-assembled via the column reinforcement fixing plate and the nuts 6a, 6b, the nuts 6a, 6b cannot be attached. In the loosened state, the vertical column main reinforcement and the bent column main reinforcement can freely move in all directions within a certain range, so it is possible to match the phase of the screw threads.Therefore, the lock nut method is used as a means of connecting column main reinforcement. By adopting a mechanical joint, it is possible to eliminate the change (reduction) in the length of the main reinforcement as in the case of gas pressure welding, and when the nuts 6a and 6b are loosened, it is possible to correct the verticality of the main reinforcement of the vertical column. By being able to correct the vertical position of the bending point between the vertical reinforcement part and the upper and lower diagonal reinforcements in the main reinforcement of the bent column, reinforcement can be arranged easily and accurately.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention,
Figure 1 is a front view of the reinforcement structure of an RC column, Figure 2 is a cross-sectional plan view of the same as above, Figure 3 is a perspective view of the same as above, Figure 4 is a side view of the main parts, Figure 5 is A, B, and C. FIG. 2 is a front view showing an example of a construction method. FIG. 6 is a plan view showing another embodiment of the present invention. 7 and 8 are a front view and a plan view showing a conventional example. A...Reinforcing bar pre-assembly unit, 1...Vertical column main reinforcement,
2...Bent column main reinforcement, 2a...Vertical reinforcement part, 2b...
...Upper diagonal reinforcement, 2c...Lower diagonal reinforcement, 5...Column reinforcement fixing plate, 6a, 6b...Nut, 7...
Hoop muscle.

Claims (1)

[Claims] 1. Between the vertical column main reinforcements at the four corners, bend the bent column main reinforcements consisting of the vertical reinforcement part corresponding to the column and beam joint part, and the upper diagonal reinforcement and lower diagonal reinforcement bent diagonally from both ends of the vertical reinforcement part. This is an RC column reinforcement structure in which the reinforcement is arranged in an X-shape when viewed, and hoop reinforcement is wrapped around the vertical column main reinforcement group, and the vertical column main reinforcement and bent column main reinforcement are each screwed together. As a reinforcing bar,
A column reinforcement fixing plate is provided in the vertical center of the column-beam joint part, and is formed in a rectangular ring shape in plan view and has a horizontal pressure-receiving surface. is inserted into the through-hole formed in the columnar reinforcement fixing plate, and is inserted into the columnar reinforcement fixing plate by each pair of nuts screwed into threaded joints of the threaded reinforcing bars. A reinforcement structure for RC columns using X-shaped reinforcement, which is characterized by being fixed in a state where it is sandwiched from both the upper and lower sides.