JP4255853B2 - Method for constructing concrete structure of prestressed structure from outside to inside using spiral hoop and its concrete structure - Google Patents

Description

  The present invention relates to a method for constructing a concrete structure having a prestressed structure from the outside to the inside using spiral hoop bars and used for a bridge pier or a foundation, and the concrete structure.

Conventionally, in RC (Reinforced Concrete) piers having a circular cross section, spiral bars are used to provide a lateral restraint effect.
“Lateral restraint effect of spiral muscle on RC pier with circular section”, Structural Engineering Papers Vol. 48A (March 2002), pp. 715-723

  However, concrete has a problem that it is easily cracked.

  The present invention can increase the strength of a concrete column by applying a prestress from the outside to the inside using a spiral hoop reinforcement. The prestressed from the outside to the inside using a spiral hoop reinforcement can be achieved. It is an object of the present invention to provide a method for constructing a concrete structure having a structure and the concrete structure.

In order to achieve the above object, the present invention provides
[1] In a construction method of a concrete structure having a prestressed structure from the outside to the inside using a spiral hoop reinforcement, the spiral hoop reinforcement wound around an axial rebar arranged in a cylindrical formwork is connected to the spiral. Applying a twisting force so as to widen the diameter of the hoop and placing the concrete in the cylindrical formwork in that state; and twisting applied to widen the diameter of the spiral hoop after the concrete is hardened The step of releasing the force and the step of removing the cylindrical formwork are performed.

  [2] A concrete structure having a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement, wherein the concrete structure has a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement described in [1]. It is constructed using the construction method of things.

  [3] In a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement described in [2], the concrete structure is an RC column.

  [4] In a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement described in [2], the concrete structure is a foundation pile.

[5] In a method for constructing a prestressed concrete structure from outside to inside using a spiral hoop, concrete is placed in a cylindrical steel pipe, and the diameter is smaller than the diameter of the cylindrical steel pipe A step of winding a spiral hoop muscle to which a twisting force is applied so as to increase the diameter of the spiral hoop muscle in an initial state, and a twisting force applied to increase the diameter of the spiral hoop muscle And a step of releasing.

  [6] In a concrete structure having a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement, the concrete structure having a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement described in [5] above. It is constructed using a construction method.

  [7] In a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement described in [6], the concrete structure is a CFT column.

  [8] In a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement described in [6], the concrete structure is a foundation pile.

  [9] In the method for constructing a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement described in [1], a deformed reinforcing bar is used as the spiral hoop reinforcement.

  [10] A concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement described in [2] to [4], wherein the spiral hoop reinforcement is a deformed reinforcing bar.

  According to the present invention, by applying a prestress by applying a torsional force that reduces the diameter of the spiral hoop to the concrete structure, the concrete effect can be increased and the strength of the concrete column can be increased. You can build things.

  In the construction method of the concrete structure of the prestressed structure from the outside to the inside using the spiral hoop reinforcement, the spiral hoop reinforcement is wound on the spiral hoop reinforcement wound around the axial rebar arranged in the cylindrical formwork. Applying a twisting force to widen the diameter, placing the concrete in the cylindrical formwork in that state, and releasing the twisting force applied to widen the diameter of the spiral hoop after the concrete is hardened And a step of removing the cylindrical formwork. Therefore, when the spiral hoop is released from the torsional force, the force to return to the original shape acts as a force to reduce the diameter, so that the restraining effect is increased and the strength of the concrete column is increased. be able to.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a schematic diagram of a manufacturing process of an RC column as a concrete structure of a prestressed structure from the outside to the inside using a spiral hoop bar showing an embodiment of the present invention, and FIG. 2 is an explanation of the action of the spiral hoop bar. FIG. 3 is a cross-sectional view of an RC column as a prestressed structure from the outside to the inside using the spiral hoop.

  (1) First, as shown in FIG. 1A, a spiral hoop bar 3 is wound around an axial reinforcing bar 2 in a cylindrical mold 1.

  (2) Next, as shown in FIG. 1B, the concrete 4 is placed in a state where a twisting force is applied so as to widen the diameter of the spiral hoop muscle 3.

  (3) Next, as shown in FIG. 1 (c), the twisting force applied to expand the diameter of the spiral hoop bar 3 after the concrete 4 is hardened is released.

  (4) Next, as shown in FIG.1 (d), the said cylindrical formwork 1 can be removed and the RC pillar 5 of a prestressed structure can be obtained.

  The action of the spiral hoop muscle 3 in that case will be described in detail. As shown in FIG. 2A, the spiral hoop muscle 3 in the initial state is changed to the diameter of the spiral hoop muscle 3 as shown in FIG. The torsional force F is applied so as to increase the diameter. Next, when concrete is placed and the twisting force F is released after the concrete is hardened, the spiral hoop muscle 3 acts to return to the initial state, as shown in FIG.

Here, how to expand the diameter of the spiral hoop muscle 3 is, as shown in FIG. 2B, the lower end portion of the spiral hoop muscle 3 in the initial state is clockwise as indicated by an arrow. On the other hand, the upper end of the spiral hoop muscle 3 in the initial state can be implemented by applying a twisting force counterclockwise as indicated by an arrow. Then, by placing concrete and releasing the twisting force applied to the lower end and upper end of the spiral hoop after the hardening, the spiral hoop 3 acts to return to the initial state, and the twist A prestress from the outside to the inside can be applied by force.

  The RC pillar 5 constructed in this way can produce a restraining effect with the force that the spiral hoop bar 3 tries to return to the original shape, in other words, the force that the diameter of the concrete 4 is reduced.

  Although the RC column has been described above, it can also be applied to foundation piles.

  In addition, as the spiral hoop reinforcement in each of the above-described embodiments, it is desirable to use a deformed reinforcing bar made of a steel bar having surface protrusions such as ribs or joints so that adhesion to the concrete can be greatly removed when embedded in the concrete.

  FIG. 4 is a schematic diagram of a manufacturing process of a CFT (concrete feel tube) column as a concrete structure having a prestressed structure from the outside to the inside using a spiral hoop bar according to an embodiment of the present invention. It is a cross-sectional view of a CFT column as a prestressed structure from the outside to the inside using the spiral hoop.

  (1) First, concrete 12 is placed in the steel pipe 11 as shown in FIG.

(2) Next, as shown in FIG. 4 (b), the spiral hoop bar 13 in an initial state having a diameter smaller than the diameter of the steel pipe 11 is wound around the outside of the steel pipe 11 in a state where the diameter is widened.

  (3) Next, as shown in FIG.4 (c), the force which expands the diameter of the spiral hoop muscle 13 is released.

  (4) Then, it is possible to obtain a CFT column 14 having a prestressed structure to which a force to reduce the diameter of the CFT column is applied by the spiral hoop muscle 13.

That is, when shifting from the above (3) to (4), the spiral hoop muscle 3 is released from the twisting force that attempts to expand the diameter, so that the force that tries to return to the original shape attempts to reduce the diameter. Thus, a compressive force acts from the outside to the inside of the CFT column, and the CFT column 14 having a large restraining effect can be obtained. In this case as well, it goes without saying that the method of expanding the diameter of the spiral hoop muscle 3 shown in FIG.

  Although the CFT pillar has been described above, it can be applied to foundation piles.

  Further, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

  The method for constructing a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop of the present invention and the concrete structure are suitable for RC bridge piers, foundation piles, and the like because the strength increases.

It is a schematic diagram of the preparation process of RC pillar as a concrete structure of the prestressed structure from the outer side to the inner side using the spiral hoop reinforcement which shows the Example of this invention. It is explanatory drawing of an effect | action of the spiral hoop muscle which shows the Example of this invention. It is a cross-sectional view of the RC column as a prestressed structure from the outside to the inside using the spiral hoop muscle showing the embodiment of the present invention. It is a schematic diagram of the manufacturing process of the CFT (concrete feel tube) column as a concrete structure of the prestressed structure from the outer side to the inner side using the spiral hoop bar which shows the example of the present invention. It is a cross-sectional view of the CFT column as a prestressed structure from the outside to the inside using the spiral hoop muscle shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical formwork 2 Axial reinforcement 3,13 Spiral hoop reinforcement 4,12 Concrete 5 RC pillar of prestressed structure 11 Steel pipe 14 CFT pillar of prestressed structure

Claims (10)

(A) A twisting force is applied to the spiral hoop muscles wound around the axial reinforcing bars arranged in the cylindrical formwork so as to widen the diameter of the spiral hoop reinforcements. A process of placing concrete;
(B) releasing the twisting force applied to expand the diameter of the spiral hoop after the concrete is hardened;
(C) A method for constructing a concrete structure having a prestressed structure from the outside to the inside using a spiral hoop reinforcement, wherein the step of removing the cylindrical formwork is performed.   The prestressed structure of the prestressed structure from the outside to the inside direction using the spiral hoop reinforcement, which is constructed using the method for constructing the concrete structure of the prestressed structure from outside to inside using the spiral hoop reinforcement according to claim 1. Concrete structure.   3. A concrete structure having a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement according to claim 2, wherein the concrete structure is a prestressed structure in the direction from the outside to the inside using a spiral hoop reinforcement in which the concrete structure is an RC pillar. Concrete structure.   The concrete structure of the prestressed structure from the outside to the inside direction using the spiral hoop reinforcement according to claim 2, wherein the concrete structure is a prestressed structure from the outside to the inside using the spiral hoop reinforcement in which the concrete structure is a foundation pile. Concrete structure. (A) Concrete is placed in a cylindrical steel pipe, and a spiral hoop muscle to which a twisting force is applied so as to widen the diameter of the spiral hoop muscle in an initial state smaller than the diameter of the cylindrical steel pipe Wrapping around the outside of the steel pipe,
(B) A method for constructing a concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement, wherein a step of releasing a twisting force applied so as to expand the diameter of the spiral hoop reinforcement is performed.   The prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement, which is constructed using the method for constructing the concrete structure having the prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement according to claim 5. Concrete structure.   7. A concrete structure having a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement according to claim 6, wherein the concrete structure is a prestressed structure in the direction from the outside to the inside using the spiral hoop reinforcement in which the concrete structure is a CFT pillar. Concrete structure.   7. A concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement according to claim 6, wherein the concrete structure is a prestressed structure from the outside to the inside using a spiral hoop reinforcement in which the concrete structure is a foundation pile. Concrete structure.   In the construction method of the concrete structure of the prestressed structure from the outer side to the inner side using the spiral hoop bar according to claim 1, a spiral hoop bar is used as the spiral hoop bar. A method of building a prestressed concrete structure from the outside to the inside.   5. A concrete structure having a prestressed structure from the outside to the inside using the spiral hoop reinforcement according to claim 2, wherein the spiral hoop reinforcement is a deformed reinforcing bar using a spiral hoop reinforcement. Prestressed concrete structure.

Images