JP4418331B2 - Bonding structure between concrete and steel - Google Patents

Description

  The present invention relates to a joint structure between a concrete material and a steel frame material. More specifically, the present invention relates to a joint structure between a concrete material and a steel frame for joining the concrete material and the steel frame so as to facilitate the reuse of the steel frame.

  Conventionally, in order to improve the proof stress and rigidity of a steel frame structure, the steel frame material is tightly coupled with a concrete material such as an RC slab (reinforced reinforced concrete plate) and reinforced. In this case, the concrete material is generally joined to the steel frame by a stud bolt attached to the steel frame.

  FIG. 9 shows an example of such a connection structure between a concrete material and a steel frame material (see Patent Document 1). In this coupling structure 100, as shown in FIG. 9, the male screw 101a provided at the tip of the stud bolt 101 is screwed into the female screw hole 102a provided in the upper flange of the steel frame (steel beam) 102. Thus, the stat bolt 101 is attached to the steel frame material 102.

  As described above, conventionally, the steel structure has been reinforced by firmly joining the steel material with the concrete material and the stud bolt. Therefore, at the time of dismantling, for example, the steel material is cut and destroyed while the steel material is removed. There is a problem that it is difficult to reuse such as using the steel frame as it is in another building.

In order to avoid this, for example, a method of separating the steel material and the concrete material while holding the concrete material at the joining portion is also conceivable. However, such work generates a large amount of noise and requires a lot of labor, and thus there are cases where construction is difficult in a residential area or the like and costs increase.
JP 2003-56127 A

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a joint structure of a concrete material and a steel material that can facilitate the reuse of the steel material.

The joint structure between a concrete material and a steel frame according to the present invention is a joint structure between a concrete material and a steel frame that facilitates the reuse of the steel frame, and is a binding member that binds the concrete material to the steel frame. A void forming member made of a metal having a low melting point such as zinc or tin is embedded in the surroundings.

Furthermore, in the joint structure of the concrete material and the steel frame of the present invention, it is preferable that the gap forming member has a core portion made of a metal having a high melting point such as iron, copper or nickel .

  Furthermore, in the joint structure of the concrete material and the steel frame according to the present invention, it is preferable that the gap forming member is formed in a coil spring shape and the fastening member is accommodated in the coil.

  According to the present invention, since a gap can be formed around the fastening member at the time of dismantling, the concrete material around the fastening member can be broken by a relatively weak impact, and the steel frame material can be easily separated from the concrete material. Therefore, the excellent effect that the reuse of the steel frame becomes easy is obtained.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

Embodiment 1
FIG. 1 is a cross-sectional view showing a joint structure between a concrete material and a steel frame according to Embodiment 1 of the present invention. FIG. 2 is a top perspective view showing the coupling structure.

  As shown in FIG. 1, the joint structure K includes a concrete material 2 and a steel frame so that a concrete material 2 made of RC slab is supported by a steel frame material (steel beam) 1 made of, for example, an H-shaped steel to form a floor 10. It is assumed that the material 1 is bonded.

  In the coupling structure K, as shown in FIGS. 1 and 2, a stud bolt (tightening member) 3 is attached to the steel frame 1, and the concrete material 2 is fastened to the steel frame 1 by the stud bolt 3. Further, in the coupling structure K, the melting member 4 having a predetermined shape is embedded in the concrete material 2 around the stud bolt 3.

  The melting member 4 is formed in a predetermined shape in which a low melting point metal such as zinc (melting point: 419 degrees Celsius) or tin (melting point: 232 degrees Celsius) can be disposed around the stud bolt 3, in the first embodiment, in a coil spring shape. It will be. Further, the melting member 4 is embedded in the concrete material 2 in contact with the steel frame material 1 so as to be able to conduct electricity through the steel frame material 1.

  Thus, when the steel structure 1 and the concrete material 2 are separated at the time of building dismantling or the like in the connection structure K, one pole of the power source E and the steel frame material 1 are connected and the other pole of the power source E is connected. And the upper end of the melting member 4 (the end that is not in contact with the steel frame 1) can be connected or conducted, and a large current is passed from the power source E to the melting member 4. Thereby, the melting member 4 is heated and melted. That is, the melting member 4 is heated and melted by a so-called direct current heating method.

  For this reason, a gap is generated in the buried portion of the melting member 4 inside the concrete material 2, the concrete material 2 becomes brittle around the stud bolt 3, and the concrete material 2 in that portion is destroyed only by applying a relatively weak impact. It becomes possible to do. That is, the melting member 4 is a gap forming member. Therefore, the steel material 1 can be easily separated from the concrete material 2 without damaging it, and it becomes easy to reuse the steel material 1 such as using the steel material 1 as it is in another building. . Moreover, since the concrete material 2 is fragile, it is easily destroyed without generating a large noise. Therefore, construction in a residential area or the like is also possible, and the labor is greatly reduced.

  Here, the heating method for melting the melting member 4 may be based on high-frequency induction heating as shown in FIG. 3 in addition to the direct current heating method. That is, it is assumed that the coil 11 to which a high-frequency alternating current is applied is brought close to the melting member 4 and an eddy current is generated on the surface of the melting member 4 by the magnetic field N generated by the coil 11, thereby heating and melting the melting member 4. Also good. In the case of high frequency dielectric heating, it is not necessary to embed the molten member 4 in the concrete material 2 in a state in which the molten member 4 is in contact with the steel frame material 1 so as to be conductive.

  Alternatively, the weld metal 4 may be heated and melted using a gas burner or the like.

  Hereinafter, a specific procedure for separating the concrete material 2 and the steel frame material 1 in the steel structure L to which the coupling structure K is applied will be described with reference to FIG.

  Procedure 1: The concrete material 2 is cut into sections M of an appropriate size by a cutter (not shown) together with the internal reinforcing bars 2a. Here, the slice M has a predetermined shape that does not fall from the framework of the steel frame 1.

  Procedure 2: The eyebolt 5 is attached to the concrete material 2 cut into the sections M by a hole-in anchor (not shown).

  Procedure 3: Pass the wire through the eyebolt 5 and hang it on the crane.

  Procedure 4: The melting member 4 is heated and melted.

  Procedure 5: The concrete material 2 is suspended by the crane.

  As described above, according to the coupling structure K of the first embodiment, when the steel frame material 1 and the concrete material 2 are coupled, the melting member 4 is made to the concrete material 2 so as to surround the stud bolt 3 attached to the steel frame material 1. When embedding and separating the steel frame material 1 and the concrete material 2 at the time of building dismantling, etc., the molten material 4 is heated and melted to make the concrete material 2 around the stud bolt 3 brittle, and in this state the steel frame material 1 and the concrete material 2 are separated. Therefore, it can be easily separated from the concrete material 2 without damaging the steel frame material 1. For this reason, while being able to aim at the reusability improvement of the steel frame material 1, it also becomes possible to aim at the improvement of the silence of construction, and reduction of labor.

Embodiment 2
Hereinafter, Embodiment 2 of the present invention will be described with reference to FIG. The coupling structure K1 of the second embodiment is obtained by modifying the first embodiment, and includes an upper end 41 having an upper surface that is flush with the surface of the concrete material 2 at the upper end of the melting member 4A. The The remaining configuration of the second embodiment is the same as that of the first embodiment.

  Specifically, in the coupling structure K1 of the second embodiment, the melting member 4A is embedded in the concrete material 2 with the upper surface of the upper end portion 41 being flush with the surface of the concrete material 2. This facilitates the connection between the power source E and the melting member 4A. Therefore, the efficiency of the building demolition work can be improved. Further, by connecting the upper surface of the upper end portion 41 of each melting member 4A with a conductor and connecting them, it is possible to energize and melt the plurality of melting members 4A simultaneously by one energization. Therefore, the efficiency of the dismantling work can be further improved. Note that the upper end portion 41 may be previously connected by a conducting wire.

Embodiment 3
Hereinafter, Embodiment 3 of the present invention will be described with reference to FIGS. 6 and 7. The third embodiment is obtained by modifying the first embodiment, and is formed by forming the melting member 4B in a straight line. The remaining configuration of the third embodiment is the same as that of the first embodiment.

  Specifically, in the coupling structure K2 of the third embodiment, a predetermined number (four in the illustrated example) of the melting members 4B formed in a straight line surround the stud bolt 3 attached to the steel frame 1. The steel material 1 is embedded in the concrete material 2 in parallel, for example. That is, since the stud bolts 3 are usually provided on the upper surface of the steel frame 1 at a predetermined interval in a row, the linear molten member 4B is embedded in the concrete material 2 in a predetermined arrangement parallel to the steel frame 1. By doing so, it becomes possible to arrange | position the fusion | melting member 4B so that all the stud bolts 3 located in a line may be enclosed simultaneously. Therefore, the efficiency of the embedding work of the melting member 4B is achieved. Here, the melting member 4 </ b> B may be arranged so as not to contact the steel frame 1.

Embodiment 4
Hereinafter, Embodiment 4 of the present invention will be described with reference to FIG. The fourth embodiment is obtained by modifying the first to third embodiments. As shown in FIG. 8, the melting member 4 </ b> C is formed from a double-structured wire 50. The remaining configuration of the fourth embodiment is the same as that of the first to third embodiments.

  That is, in the first to third embodiments, when the melting member 4C is heated and melted by the direct current heating method, a part of the melting member is melted first, and the whole is not melted due to a disconnected state. There is. When such unmelted residue occurs, the concrete material 2 in that portion does not become brittle, and it is difficult to break the concrete material 2.

  Therefore, in the fourth embodiment, the wire 50 constituting the melting member 4C is composed of a core 51 made of a metal having a relatively high melting point (iron, copper, nickel, gold, etc., melting point: 1000 to 1500 degrees Celsius); The covering member 52 is made of a low melting point metal (zinc, tin, etc.), and the melting member 4C is heated so that the covering portion 52 is melted but the core portion 51 is not melted. Thereby, it is possible to prevent the melting member 4C from remaining undissolved. Here, if the diameter of the wire 50 is, for example, 10 mm, the diameter of the core 51 is, for example, 2 to 3 mm.

  Thus, in Embodiment 4, since the wire 50 which comprises the fusion | melting member 4C is made into the double structure which has the core part 51 which consists of a high melting point metal, and the coating | coated part 52 which consists of a low melting point metal, As a result, when the melting member 4C is heated and melted, the melting member 4C is not left undissolved, and the separation work of the steel frame material 1 and the concrete material 2 can be facilitated more reliably.

  Further, the melting member 4C is not formed entirely from a low melting point metal, but is formed by including an inexpensive metal (such as iron) having a high melting point, thereby reducing the cost.

  The present invention can be applied to various steel structures in which a concrete material and a steel frame material are coupled by a stud bolt.

It is sectional drawing which shows the joint structure of the concrete material and steel frame which concern on Embodiment 1 of this invention. It is a top perspective view of the joint structure. It is sectional drawing which shows another example of the heating-melting method of the melting member of the same connection structure. It is a schematic diagram which shows the detail of the isolation | separation procedure of the concrete material and steel frame material in the joint structure. It is sectional drawing which shows the connection structure of the concrete material of Embodiment 2 of this invention, and a steel frame material. It is a perspective view which shows the joint structure of the concrete material and steel frame of Embodiment 3 of this invention. It is sectional drawing of the joint structure. It is sectional drawing of the fusion | melting member used for the connection structure of the concrete material of Embodiment 4 of this invention, and a steel frame material. It is sectional drawing which shows an example of the connection structure of the conventional concrete material and steel frame material.

Explanation of symbols

K, K1, K2 binding structure
1 Steel frame
2 Concrete material
3 Stud bolt, Tightening member 4, 4A-4C Melting member
50 wire rod
51 heart
52 Covering part

Claims (3)

It is a joint structure between a concrete material and a steel frame that facilitates the reuse of the steel frame,
A joining structure of a concrete material and a steel frame, characterized in that a void forming member made of a low melting point metal such as zinc or tin is embedded around a fastening member for binding the concrete material to the steel frame. Junction structure of the gap forming member, iron, copper, concrete material and steel material according to claim 1, characterized by having a core made of a refractory metal such as nickel. Gap forming member is formed into a coil spring shape, the junction structure between the concrete material and the steel material according to claim 1, wherein the tie element therein coil is characterized by comprising housed.

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