JP2732025B2 - Joint structure of rebar using shape memory alloy members - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure of a reinforcing steel bar using a shape memory alloy member.

[0002]

2. Description of the Related Art Conventionally, there have been known mechanical joints such as coupler-type and grip-type mechanical joints and press-welding-type welded joints, and others using a shape memory alloy member have been proposed. I have.

[0003] A joint of a reinforcing bar described in Japanese Patent Application Laid-Open No. 58-26155 is designed to prevent loose rattling between the reinforcing bar and the coupler by interposing a member made of a shape memory alloy when connecting the reinforcing bar with a screw coupler. I made it.

[0004] In the rebar joint device disclosed in Japanese Utility Model Laid-Open No. 4-111813, a plate-like spring-shaped shape memory alloy for pressing a pressing member against a rebar is arranged inside a highly rigid cylindrical body.

[0005]

However, these conventional joints of reinforcing bars have an auxiliary role of enhancing the action of other restraining members, rather than directly restraining the reinforcing bars with a member made of a shape memory alloy. However, the number of members is large, and the set is troublesome.

It is an object of the present invention to provide a joint structure for a reinforcing steel bar made of a shape memory alloy member which has a simple structure and which can obtain an effective restraining action with a small number of members. is there.

[0007]

According to the present invention, in order to achieve the above object, one rebar joint is inserted from one end of a restraining member made of a shape memory alloy formed into a coil shape, and the other is inserted from the other end. The gist is that a rebar joint is inserted so that the shape memory alloy member performs a tightening action by hydration heat when concrete hardens.

[0008]

According to the present invention, the shape memory alloy member for restraining the reinforcing steel bar to be connected is formed in a coil shape, that is, a spiral body. And the diameter of the spiral can be reduced, and the rebar ends can be tightened directly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 5 are perspective views of respective steps showing a first embodiment of a joint structure of a reinforcing steel bar using a shape memory alloy member according to the present invention.
Are joined.

As shown in FIG. 1, a joint reinforcing bar joint 3 corresponding to an end of a reinforcing bar is protruded from an upper end of a lower column member 1.
The periphery thereof is bent by the PC form 4. On the other hand, similarly, the upper column member 2 to be joined to the lower column member 1 also has a joint reinforcing bar 5 projecting from the lower end thereof, and a PC form 4 around the joint.
It is surrounded and bent. In addition, the PC form 4 is configured such that the outer circumferences similar to the pillars 1 and 2 are formed by abutting each other, and one or both of the rebar joint 3 and the rebar joint 5 are more than the PC form 4. It shall be longer.

In FIG. 2, reference numeral 6 denotes a restraining member made of a shape memory alloy formed in a coil shape. The reinforcing member 3 is inserted from one end of the restraining member 6 so that the reinforcing joint 3 is inserted.
The restraining member 6 is set around.

When the upper column 2 is erected in this manner, if the reinforcing joint 5 is brought into contact with the reinforcing joint 3, the reinforcing joint 5 is inserted from the other end of the restraining member 6 into the inside thereof. As a result, the restraining member 6 is set around the rebar joint 5.

The butted lower column 1 and upper column 2 are filled with concrete 7 in the inner space where the PC form 4 is abutted.
Is injected and filled, the abutting rebar joint 3 and the rebar joint 5 and the surrounding constraining member 6 made of a shape memory alloy formed into a coil shape are also buried in the concrete 7.

Although the temperature rises due to the hydration reaction of the concrete 7, the restraint member 6 made of the shape memory alloy recovers its shape by such a temperature change, and reduces both the space between the spirals and the spiral diameter. Tighten 3,5. In particular, since the shape of the restraining member 6 is coil-shaped, when the shape recovery temperature is reached, the spring is in a state close to a cylinder in which a spring is crushed, and a strong tightening force that tightens the outer periphery of the rebar joints 3 and 5 on the surface is obtained. can get.

The shape memory alloy forming the restraining member 6 will be described. The shape memory alloy coil spring is stored in advance in the coil inner diameter smaller than the outer diameter of the reinforcing bar,
It is made of a shape memory alloy having a transformation temperature (austenite transformation end temperature) at 60 ° C. The shape memory alloy coil spring is expanded at room temperature to an inner diameter larger than the outer diameter of the reinforcing bar, and is set outside the reinforcing bar as a joint. As the shape memory alloy, any of copper-based and iron-based alloys can be used in addition to the NiTi-based alloy, but the NiTi-based shape memory alloy is the best in terms of the generated stress, recovery strain, corrosion resistance, etc. Optimal.

In the first embodiment, the rebar joint 3 and the rebar joint 5 are opposed to each other. However, the rebar joint 3 may be a lap joint in which the rebar joints are overlapped.
It may be a double spiral type.

Also, the present invention can be used for a joint of a reinforcing bar arranged in a formwork even when the column members 1 and 2 are formed on site.
In some cases, the C-form 4 is not used.

FIG. 6 shows a second embodiment of the present invention.
The lower column member 1 has a metal cylindrical body 8 buried in the joint end face so that the end is open, and the reinforcing steel joint 3 is protruded therein.

When the upper column 2 is to be built, the cylindrical body 8
A reinforcing member 3 made of a shape memory alloy formed into a coil shape is arranged around the reinforcing joint 3 and the reinforcing joint 5 of the upper column 2 in the inside thereof, and the concrete 7 is filled. did.

Further, as a third embodiment, as shown in FIGS. 10 to 12, a sleeve 9 provided with a slit 9a for imparting elasticity is used for abutting the rebar joints 3, 5 with each other. , 5 and a constraining member 6 made of a shape memory alloy formed in a coil shape is attached to the outer periphery of the sleeve 9 and tightened from the outside.

In this case, the rebar joints 3 and 5 are ends of a screw rebar, and the sleeve 9 may be a screw coupler.

In the above embodiment, the joint between the columns has been described, but the present invention can be similarly applied to the joint between the column and the beam. 13, 14, and 15, reference numeral 10 denotes a formwork, and a beam is attached to the column 11.
To join 12, the reinforced joint 13 on the column 11 and the reinforced joint 14 on the beam 12 are abutted or lap jointed, and a shape memory alloy formed into a coil around them The restraining member 6 is arranged, and concrete is poured into the mold 10 though not shown.

Further, as shown in FIG.
It may be possible to omit the demolding work by integrating with the concrete to be cast as 15.

[0024]

As described above, the joint structure of the rebar using the shape memory alloy member of the present invention has a simple structure, and
An effective restraining action can be obtained with a small number of members.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first step showing a first embodiment of a joint structure for a reinforcing bar using a shape memory alloy member of the present invention.

FIG. 2 is a perspective view of a second step showing the first embodiment of the joint structure of the reinforcing steel using the shape memory alloy member of the present invention.

FIG. 3 is a perspective view of a third step showing the first embodiment of the joint structure of a reinforcing bar using the shape memory alloy member of the present invention.

FIG. 4 is a perspective view of a fourth step showing the first embodiment of the joint structure for a reinforcing bar using the shape memory alloy member of the present invention.

FIG. 5 is a perspective view of a fifth step showing the first embodiment of the joint structure for a reinforcing bar using the shape memory alloy member of the present invention.

FIG. 6 is a perspective view showing a second embodiment of the joint structure of a reinforcing steel bar using the shape memory alloy member of the present invention.

FIG. 7 is a longitudinal sectional side view of a first step showing a second embodiment of the joint structure of a reinforcing bar using the shape memory alloy member of the present invention.

FIG. 8 is a longitudinal sectional side view of a second step showing a second embodiment of the joint structure of a reinforcing steel bar using the shape memory alloy member of the present invention.

FIG. 9 is a vertical sectional side view of a third step showing a second embodiment of the joint structure of the reinforcing steel using the shape memory alloy member of the present invention.

FIG. 10 is a perspective view showing a third embodiment of a joint structure for a reinforcing steel bar using the shape memory alloy member of the present invention.

FIG. 11 is a perspective view showing an example of a sleeve to be used.

FIG. 12 is a perspective view showing another example of a sleeve to be used.

FIG. 13 is a longitudinal sectional side view showing a fourth embodiment of the joint structure of a reinforcing steel bar using the shape memory alloy member of the present invention.

FIG. 14 is a longitudinal sectional side view showing a fifth embodiment of the joint structure of a reinforcing steel bar using the shape memory alloy member of the present invention.

FIG. 15 is a longitudinal sectional side view showing a sixth embodiment of the joint structure of a reinforcing steel bar using the shape memory alloy member of the present invention.

FIG. 16 is a longitudinal sectional side view showing a seventh embodiment of the joint structure of a reinforcing steel bar using the shape memory alloy member of the present invention.

[Explanation of symbols]

1,2 ... column material 3,5 ... reinforcement joint 4 ... PC form 6 ... restraint member by shape memory alloy 7 ... concrete 8 ... metal cylinder 9 ... sleeve 9a ... slit 10 ... form 11 ... post 12 ... beam 13, 14… Reinforcing bar joint 15… PC formwork

Claims (1)

(57) [Claims] 1. A rebar joint is inserted from one end of a constraining member made of a shape memory alloy formed into a coil shape, and the other rebar joint is inserted from the other end. A joint structure of a reinforcing bar made of a shape memory alloy member, wherein a tightening action is performed by heat of hydration when it is hardened.