JP2022076845A - Construction method of concrete structure and concrete structure - Google Patents

Abstract

To provide a construction method of a concrete structure, etc. that facilitate design and construction work.SOLUTION: A reinforcement cage 1 includes a plurality of flexible strands 11 that are arranged in a circumferential direction of the reinforcement cage 1 leaving an interval therebetween, and the reinforcement cage 1 is disposed in a vertical shaft 3 formed in a ground 2. Then, a top end portion of the strand 11 is deflected and anchored on a steel tower leg section 4. By casting concrete, a foundation is constructed that has the reinforcement cage 1 and an anchored portion embedded in the concrete, the anchored portion being a location where the top end portion of the strand 11 has been anchored on the steel tower leg section 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for constructing a concrete structure and the like.

Concrete may be placed in a shaft formed in the ground to construct a concrete foundation such as a deep foundation of a steel tower. When an inclined steel column such as a steel tower leg is provided on a concrete foundation, it is necessary to transmit the lifting force generated in the steel column by the wind load to the concrete foundation.

Therefore, for example, Patent Document 1 describes that a ring-shaped bearing plate projecting laterally from a tower leg is provided, and concrete is cast around the support plate to construct a foundation. In addition, a squid-type fixing structure is also known in which a steel material is extended laterally from the tower leg and integrated with the concrete of the foundation.

Japanese Unexamined Patent Publication No. 2000-345571

In the conventional structure, the lifting force of the tower leg due to the wind load acts on the joint between the tower leg and the foundation, but the inclined tower leg and the vertical foundation are not smoothly continuous and are bent. The joints are in a complex stress state, requiring complex design and construction considerations for safety.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for constructing a concrete structure that can be easily designed and constructed.

In the first invention for solving the above-mentioned problems, a plurality of flexible axial steel materials arranged at intervals in the circumferential direction of the reinforcing bar cage and the circumference of the reinforcing bar cages arranged in a plurality of upper and lower stages are provided. A step of arranging a reinforcing bar cage formed in a shaft formed in the ground by joining a reinforcing bar in the direction and a temporary ring in the circumferential direction of the reinforcing bar cage arranged at the upper end of the reinforcing bar cage above the reinforcing bar (reinforcing bar). A) and a step (b) of removing the temporary ring, bending the upper end portion of the axial steel material, and fixing the upper end portion to the inclined pillar body, by placing concrete. , The method for constructing a concrete structure, characterized in that the reinforcing bar cage and the fixed portion in which the upper end portion of the axial steel material is fixed to the pillar body are embedded in concrete.

In the present invention, a reinforcing bar cage provided with a flexible axial steel material is used, and the upper end thereof is bent and fixed to an inclined pillar such as a tower leg. Therefore, the pillar body and the reinforcing bar cage in the foundation can be smoothly connected, the joint portion does not become a complicated stress state, and its design and construction become easy. In addition, the work is easy by building the reinforcing bar cage in the shaft with the upper end of the flexible axial steel material held by the temporary ring, removing the temporary ring, and fixing the upper end to the pillar. become.

It is desirable that the pillar has a projecting portion that projects laterally, and the upper end portion of the axial steel material is fixed to the projecting portion.
By fixing the upper end portion of the axial steel material to a projecting portion such as a bearing plate or a steel material that protrudes laterally from the pillar body, construction becomes easy.

It is desirable that the reinforcing bar cage is vertically stretchable by rotatably joining the axial steel material, the strip bar and the temporary ring.
A reinforcing bar cage is, for example, rotatably joined to an axial steel material with a band bar or a temporary ring, and the distance between the upper and lower band bars or the like increases or decreases as the intersection angle between the axial steel material and the band bar changes. , The axial steel material is in an extended state orthogonal to the strips, etc., and the axial steel material is tilted with respect to the strips, etc., and is twisted in a spiral shape. Makes construction easier.

It is desirable that the pillar body is a cylindrical socket into which a pillar can be inserted.
In this case, a relatively lightweight socket may be arranged to construct the foundation, and then a pillar may be inserted and fixed to the socket, so that temporary fixing of the socket or the like becomes easy and construction becomes easy.

The second invention has a reinforcing bar cage arranged in a shaft formed in the ground and an inclined pillar body, and a plurality of the reinforcing bar cages are arranged at intervals in the circumferential direction of the reinforcing bar cage. It is made by joining a flexible axial steel material and a circumferential band of reinforcing bars arranged in a plurality of upper and lower stages, and the upper end portion of the axial steel material is bent and fixed to the pillar body. , The reinforcing bar cage, and the fixed portion in which the upper end portion of the axial steel material is fixed to the pillar body are embedded in concrete.
The pillar body is, for example, a cylindrical socket, and the pillar is inserted into the socket.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for constructing a concrete structure that can be easily designed and constructed.

The figure which shows the foundation 100. The figure which shows the reinforcing bar cage 1. The figure which shows the construction method of the foundation 100. The figure which shows the fixing method of the upper end part of a strand 11. An example in which the bearing plate 41 is provided in a plurality of upper and lower stages. The figure which shows the cylinder 42a and the washer 42b. The figure which shows the protrusion plate 41a. The figure which shows the plate-shaped rib 43 and the steel material 44. The figure which shows the reinforcement ring 12a, 12b, 12c. The figure which shows the socket 6.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(1. Foundation structure 10)
FIG. 1 is a diagram showing a foundation 100 which is a concrete structure constructed by the construction method according to the embodiment of the present invention. The foundation 100 is a deep foundation of a steel tower, but it is not limited to this.

The foundation 100 is constructed by placing concrete in a shaft 3 formed in the ground 2, and a reinforcing bar cage 1 is buried inside the concrete. Further, in the upper part of the foundation 100, a root-wrapping concrete 102 is provided around the tower leg portion 4.

The tower leg 4 is a steel column, and is formed of a steel pipe in the present embodiment, but may be formed of a shaped steel. The tower leg portion 4 is inclined with respect to the vertical direction, and a flange-shaped bearing plate 41 (projecting portion) projecting outward from the outer surface of the steel pipe is provided at a predetermined position in the axial direction thereof.

The reinforcing bar cage 1 has a strand 11 and a strip 12, and the upper end portion of the strand 11 is fixed and fixed to the bearing plate 41 of the tower leg portion 4.

(2. Reinforcing bar cage 1)
FIG. 2 is a diagram showing a reinforcing bar cage 1. The reinforcing bar cage 1 can be expanded and contracted up and down, FIG. 2 (a) shows a state in which the reinforcing bar cage 1 is completely extended, (c) is a state in which the reinforcing bar cage 1 is completely contracted, and (b) is an intermediate state. It is a figure which showed.

As mentioned above, the reinforcing bar cage 1 has a strand 11 and a band bar 12. The strands 11 are axial steel materials of the reinforcing bar cage 1, and a plurality of strands 11 are arranged at intervals in the circumferential direction of the reinforcing bar cage 1. The band 12 is a reinforcing bar provided in the circumferential direction of the reinforcing bar cage 1 so as to surround the strand 11, and is arranged in a plurality of upper and lower stages. The stirrups 12 and the strands 11 are rotatably joined at their intersections.

Further, at the upper end of the reinforcing bar cage 1, a temporary ring 13 in the circumferential direction of the reinforcing bar cage 1 is provided so as to surround the strand 11 as in the band bar 12. The temporary ring 13 is arranged in a plurality of upper and lower stages above the band bar 12, and is rotatably joined to the strand 11 like the band bar 12. The temporary ring 13 can be removed from the strand 11. The temporary ring 13 may be arranged inside the strand 11 instead of outside, or may be arranged both inside and outside.

The strand 11 is made by twisting a plurality of PC steel wires and has flexibility. The reinforcing bar cage 1 is formed by twisting the strand 11 in the circumferential direction of the reinforcing bar cage 1 as shown by the arrow A in FIG. 2 (a), thereby forming the strand 11 and the band as shown in FIGS. 2 (b) and 2 (c). The crossing angle of the reinforcing bars 12 and the like (the reinforcing bars 12 and the temporary ring 13) is changed to form a spiral shape in which the strand 11 is inclined with respect to the reinforcing bars 12 and the like, and the distance between the upper and lower reinforcing bars 12 and the like is shortened to reduce the total length of the reinforcing bar cage 1. Can be reduced. On the other hand, by extending the strand 11 in a straight line and eliminating the twist, the strand 11 and the reinforcing bar 12 and the like are orthogonal to each other, and the distance between the upper and lower reinforcing bars 12 and the like is restored. It is possible to return the basket 1 to its original length.

(3. Construction method of foundation 100)
Next, a method of constructing the foundation 100 using the reinforcing bar cage 1 will be described with reference to FIG. 3 and the like.

As shown in FIG. 3A, in the present embodiment, the shaft 3 is first formed on the ground 2.

After that, as shown in FIG. 3 (b), the reinforcing bar cage 1 is arranged on the upper part of the shaft 3. The reinforcing bar cage 1 is tied up with a lashing material (not shown) such as a string to bring it into a contracted state, and the upper end and the lower end of the reinforcing bar cage 1 are separated from different suspension devices (not shown) to wire rods 5a such as wires. Suspended by 5b.

From this state, when the lashing of the reinforcing bar cage 1 is released and the wire rod 5b attached to the lower end portion of the reinforcing bar cage 1 is extended downward, the lower end portion of the reinforcing bar cage 1 extends downward. As a result, as shown in FIG. 3C, the reinforcing bar cage 1 extends, and the lower end portion of the reinforcing bar cage 1 reaches the bottom portion of the shaft 3. Alternatively, the rebar cage 1 in a lashed state may be suspended from the bottom of the shaft 3, the lashing may be released at the bottom, and the upper end of the reinforced cage 1 may be lifted and extended upward until it reaches a predetermined height. ..

After arranging the reinforcing bar cage 1 in the shaft 3 in this way, as shown in FIG. 3 (d), the concrete of the foundation 100 is poured to the position below the temporary ring 13 in the middle portion of the shaft 3. Then, the temporary ring 13 is removed, the tower leg portion 4 is temporarily fixed to the upper part of the concrete as shown in FIG. 3 (e), and the upper end portion of the strand 11 is bent as shown in FIG. 3 (f). The upper end portion is fixed and fixed to the tower leg portion 4.

FIG. 4A is a diagram showing a method of fixing the strand 11. In the present embodiment, the condominium 111 is provided at the upper end of the strand 11. The apartment 111 is a fixing portion for fixing the upper end portion of the strand 11 to the bearing plate 41 of the tower leg portion 4, and has a screw. The upper end of the strand 11 is fixed and fixed to the bearing plate 41 by inserting the apartment 111 into a hole (not shown) provided in the bearing plate 41 from below and screwing it into the nut 112 on the upper surface of the bearing plate 41. To.

Here, the protrusion length at which the upper end portion of the strand 11 projects upward from the uppermost band bar 12 differs depending on the position in the circumferential direction of the reinforcing bar cage 1 as shown in FIG. 3 (e). That is, the protruding length of the strand 11 at the position corresponding to the direction in which the tower leg 4 is inclined (corresponding to the right side of FIG. 3E) is smaller than that of the strand 11 at the position opposite to it.

For the strand 11 having a small protrusion length, the upper end portion thereof is fixed to the bearing plate 41 at a position corresponding to the direction in which the tower leg portion 4 is inclined (corresponding to the right side in FIG. 4A). The strand 11 having a large protrusion length is fixed to the bearing plate 41 at a position opposite to the strand 11. As a result, extra bending does not occur in the strand 11, which is preferable from the viewpoint of stress transmission between the tower leg 4 and the reinforcing bar cage 1 and workability.

Further, the strand 11 is arranged so as to have a straight line portion B having a constant length parallel to the tower leg portion 4 below the bearing plate 41 from the viewpoint of stress transmission. In the example of FIG. 4A, the bearing plate 41 is provided so as to be orthogonal to the axial direction of the tower leg portion 4, but as shown in FIG. 4B, the bearing plate 41 is provided in the horizontal direction. You may. In the case of FIG. 4A, it becomes easy to arrange the strand 11 in parallel with the tower leg portion 4, and in the case of FIG. 4B, the difference in the protruding length of the upper end portion of the strand 11 from the band bar 12. Can be made smaller.

After fixing the upper end portion of the strand 11 to the bearing plate 41 in this way, the formwork 5 for forming the root-wrapping concrete 102 is arranged as shown in FIG. 3 (f).

Then, by placing concrete in the upper part of the shaft 3 and in the formwork 5, the reinforcing bar cage 1 and the fixed portion (support plate 41) in which the upper end of the strand 11 is fixed to the tower leg 4 are buried in the concrete. The foundation 100 of FIG. 1 is constructed.

As described above, in the present embodiment, the reinforcing bar cage 1 provided with the flexible strand 11 is used, and the upper end portion thereof is bent and fixed to the tower leg portion 4. Therefore, the tower leg portion 4 and the reinforcing bar cage 1 in the foundation 100 can be smoothly continuous, and the joint portion does not become a complicated stress state, and its design and construction become easy. Further, the reinforcing bar cage 1 is built in the shaft 3 with the upper end portion of the flexible strand 11 held by the temporary ring 13, the temporary ring 13 is removed, and the upper end portion is fixed to the tower leg portion 4. This makes the work easier.

In particular, in the present embodiment, the foundation 100 can be easily constructed by using the vertically expandable reinforcing bar cage 1 in which the strand 11 is rotatably joined to the band bar 12 and the like.

Further, the upper end portion of the strand 11 is fixed to the bearing plate 41 projecting laterally from the tower leg portion 4, so that the construction can be facilitated.

However, the present invention is not limited to the above embodiments. For example, as shown in FIG. 5, when the number of strands 11 is large, a plurality of bearing plates 41 may be provided above and below, and the upper end portion of the strands 11 may be dispersed and fixed to each bearing plate 41.

The fixing position of the strand 11 in the circumferential direction of the bearing plate 41 is different between the upper and lower bearing plates 41, and is changed in a staggered manner, for example. Further, as shown by C in the figure, the bending start positions of the strands 11 are set to different positions in the upper and lower directions between the strands 11 fixed to the upper and lower bearing plates 41, and the stress transmission surface is to moderate the bending of each strand 11. Is preferable.

Further, as shown in FIG. 6A, when the tower leg 4 and the bearing plate 41 are orthogonal to each other, a cylinder 42a protruding upward from the bearing plate 41 is provided at a fixed position of the strand 11, and the upper surface of the cylinder 42a is provided. By screwing the apartment 111 into the nut 112, the fixed height of the strand 11 may be made constant in the circumferential direction of the bearing plate 41. Thereby, as in the example of FIG. 4B described above, the difference in the protruding length from the band bar 12 at the upper end of the strand 11 can be reduced.

Further, as shown in FIG. 6B, when the bearing plate 41 is provided in the horizontal direction, a washer 42b whose upper surface is inclined in a direction orthogonal to the tower leg 4 is provided, and the condominium 111 is attached to the nut 112 on the upper surface. It may be screwed. As a result, the condominium 111 at the upper end of the strand 11 is fixed at an inclination that matches the tower leg 4, and the straight portion B of the strand 11 parallel to the tower leg 4 is formed in the same manner as in the example of FIG. 4A described above. It becomes easy to form.

Further, as shown in FIG. 7A, instead of the ring-shaped bearing plate 41, an independent protruding plate 41a (protruding portion) is projected outward from the tower leg portion 4 for each fixed position of each strand 11. It may be provided. In this example, a plurality of projecting plates 41a projecting in the direction orthogonal to the tower leg 4 are provided at the same height, whereby the difference in the projecting length from the band bar 12 at the upper end of the strand 11 is described. Can be made small, and it becomes easy to form a straight portion B of the strand 11 parallel to the tower leg portion 4.

The protruding plate 41a is provided with a hole (not shown) for passing the condominium 111, but instead of this, a U-shaped notch 411 is provided as shown in the protruding plate 41a'in FIG. 7 (b). It may be provided. The condominium 111 may be inserted into the notch 411 from the side as shown by an arrow, so that the condominium 111 can be easily fixed and fixed to the protruding plate 41a', and the width of the notch 411 can be reduced. The notch 411 is also applicable to the bearing plate 41 described above and the steel material 44 described later.

In addition, as shown in FIG. 8, a plate-shaped rib 43 projecting laterally from the tower leg 4 is provided, steel materials 44 having an H-shaped cross section are fixed on both left and right sides thereof, and the upper end portion of the strand 11 is placed in the horizontal portion thereof. It may be fixed. The plate-shaped rib 43 and the steel material 44 form a protrusion in the present invention.

Further, the strand 11 which was linear in the shaft 3 becomes an S-shaped curve up to the bearing plate 41 of the inclined steel tower leg portion 4. When a tensile force is applied to the strand 11 in a section where a high-strength steel material such as the strand 11 becomes curved, a bearing pressure corresponding to the curvature is generated in the concrete inside the curve. It is desirable to place reinforcing steel materials. That is, in the present embodiment, it is desirable to dispose the reinforcing steel material inside the strand 11 at the lower part of the S-shaped section and outside the strand 11 at the upper part.

At this time, as shown in FIG. 9A, the upper part of the S-shaped section is reinforced with a reinforcing steel material so as to surround the linear portion of the strand 11 (see reference numeral B in FIG. 4A). A ring 12a may be provided to reinforce the upper part of the S-shaped section. The reinforcing ring 12a can be provided around the upper part of the S-shaped section after fixing the upper end portion of the strand 11 to the bearing plate 41. As shown in FIG. 9B, the reinforcing ring 12a is previously fastened on the lower surface of the bearing plate 41, fixed to the bearing plate 41 at the upper end of the strand 11, and then released in a bamboo blind shape. It is also possible to expand to.

On the other hand, for the lower part of the S-shaped section, a reinforcing ring 12b can be provided inside the strand 11 as shown in FIG. 9A. The reinforcing ring 12b can be, for example, tied to the lower end of the tower leg 4 in advance, fixed to the bearing plate 41 at the upper end of the strand 11, and then untied and expanded upward in a bamboo blind shape. be.

In a general reinforced concrete bar member having a circular cross section, it is necessary to arrange the reinforcing bars so as to surround the axial reinforcing bars against the shearing force acting on the members. In this embodiment as well, the shearing force of the shaft 3 needs to be arranged. It is desirable to arrange the necessary reinforcing steel material on the outside of the strand 11. The reinforcing ring 12c of FIG. 9A is provided as the reinforcing steel material, and is arranged outside the strand 11 at the lower part of the S-shaped section. As shown in FIG. 9B, the reinforcing ring 12c can be fixed to the bearing plate 41 in the same manner as the reinforcing ring 12a described above, and can be deployed downward in a blind shape.

Further, in the present embodiment, the upper end portion of the strand 11 is fixed to the bearing plate 41 of the tower leg portion 4, but instead, as shown in FIG. 10, a cylindrical shape for inserting the tower leg portion 4 (pillar). A bearing plate 61 similar to the bearing plate 41 may be provided in the socket 6 (column body) of the above, and the upper end portion of the strand 11 may be fixed to the bearing plate 61.

In this case, the socket 6 is temporarily fixed in the step shown in FIG. 3 (e), the upper end of the strand 11 is fixed to the bearing plate 61, and then the upper part of the shaft 3 and the inside of the formwork 5 are fixed. The foundation 100 is constructed by placing concrete, and then the tower leg portion 4 is inserted and fixed in the socket 6. Since the temporary fixing may be performed on the relatively lightweight socket 6 which is lighter in weight than the tower leg 4, the construction can be easily performed. In addition, the members required for temporary fixing can be simplified and the cost can be reduced.

Further, unlike the steel tower leg 4, the socket 6 can be stably temporarily fixed for a long time. Therefore, the socket 6 is arranged before concrete is placed in the shaft 3, and the upper end of the strand 11 is fixed to the socket 6. After installing the formwork 5, concrete may be poured into the shaft 3 and the formwork 5 at once. In this case, since the concrete is not spliced as described above, it contributes to the improvement of the quality of the foundation 100.

Further, in the present embodiment, the length of protrusion of the upper end portion of the strand 11 from the band bar 12 is changed according to the position in the circumferential direction of the reinforcing bar cage 1, but the strand 11 can be expanded and contracted so that the upper end portion of the strand 11 can be expanded and contracted. The protrusion length may be the same. Further, the length of protrusion of the upper end portion of the strand 11 from the band bar 12 may be the same, and the length of the apartment 111 may be changed according to the position of the reinforcing bar cage 1 in the circumferential direction. Since the condominium 111 has a large diameter, there is no particular problem in joining the temporary ring 13 to the condominium 111.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or modified examples within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

1: Reinforcing bar cage 2: Ground 3: Shaft sink 4: Steel tower leg 5: Formwork 6: Socket 10: Foundation structure 11: Strand 12: Reinforcing bar 13: Temporary ring 41, 61: Support plate 41a, 41a': Protruding plate 100: Foundation 111: Mansion 112: Nut

Claims (6)

Flexible axial steel materials arranged at intervals in the circumferential direction of the reinforcing bar cage, circumferential reinforcing bars of the reinforcing bar cages arranged in multiple stages above and below, and reinforcing bars above the reinforcing bars. The step (a) of arranging the reinforcing bar cage, which is joined to the temporary ring in the circumferential direction of the reinforcing bar cage arranged at the upper end of the cage, in the shaft formed in the ground, and
The step (b) of removing the temporary ring, bending the upper end portion of the axial steel material, and fixing the upper end portion to the inclined pillar body.
Have,
A concrete structure characterized by constructing a concrete structure in which a reinforcing bar cage and a fixed portion in which an upper end portion of the axial steel material is fixed to the pillar body are embedded in concrete by placing concrete. How to build. The pillar has a laterally protruding portion and has a protrusion.
The method for constructing a concrete structure according to claim 1, wherein the upper end portion of the axial steel material is fixed to the protruding portion. The concrete structure according to claim 1 or 2, wherein the reinforcing bar cage is a structure that can be expanded and contracted vertically by rotatably joining the axial steel material, the band bar, and the temporary ring. How to build. The method for constructing a concrete structure according to any one of claims 1 to 3, wherein the pillar body is a cylindrical socket into which a pillar can be inserted. Reinforcing bar cages placed in the shaft formed on the ground,
With a sloping pillar
Have,
The reinforcing bar cage is formed by joining a plurality of flexible axial steel materials arranged at intervals in the circumferential direction of the reinforcing bar cage and a circumferential band of the reinforcing bar cages arranged in a plurality of upper and lower stages. And
The upper end of the axial steel material bends and is fixed to the pillar.
A concrete structure characterized in that a reinforcing bar cage and a fixed portion in which an upper end portion of the axial steel material is fixed to the pillar body are embedded in concrete. The concrete structure according to claim 5, wherein the pillar body is a cylindrical socket, and the pillar is inserted into the socket.

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