JP7422054B2 - Concrete structure construction method and concrete structure - Google Patents

Description

The present invention relates to a method for constructing a concrete structure, etc.

Concrete is sometimes poured into a shaft formed in the ground to construct a concrete foundation such as a deep foundation for a steel tower. When installing inclined steel columns such as steel tower legs on a concrete foundation, it is necessary to transmit the uplift force generated on the steel columns due to wind loads to the concrete foundation.

Therefore, for example, Patent Document 1 describes that a ring-shaped bearing plate is provided that protrudes laterally from a steel tower leg, and that a foundation is constructed by pouring concrete around the ring-shaped bearing plate. Another well-known anchor structure is one in which steel extends laterally from the tower legs and is integrated with the concrete foundation.

Japanese Patent Application Publication No. 2000-345571

In conventional structures, the uplifting force of the tower legs due to wind loads acts on the joint between the tower legs and the foundation, but since the inclined tower legs and the vertical foundation are not connected smoothly and are bent, Joints are subject to complex stress conditions, 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 of constructing a concrete structure, etc., which can be easily designed and constructed.

A first invention for solving the above-mentioned problems includes a plurality of flexible axial steel members arranged at intervals in the circumferential direction of a reinforcing bar cage, and a circumference of the reinforcing bar cage arranged in multiple stages above and below. A process of arranging a reinforcing bar cage in which the reinforcing bar cage is joined with the reinforcing bars in the direction and a temporary ring in the circumferential direction of the reinforcing bar cage placed at the upper end of the reinforcing bar cage above the said ties, in a shaft formed in the ground ( a) and step (b) of removing the temporary ring, bending the upper end of the axial steel member, and fixing the upper end to the inclined column, and placing concrete. , a method for constructing a concrete structure, characterized in that a concrete structure is constructed in which the reinforcing bar cage and a fixed part of the upper end of the axial steel member fixed to the column are buried in concrete.

In the present invention, a reinforcing bar cage including a flexible axial steel member is used, and the upper end thereof is bent and fixed to an inclined column such as a steel tower leg. Therefore, the column and the reinforcing bar cage in the foundation can be smoothly connected, and the joints will not be in a complicated stress state, making their design and construction easier. In addition, the reinforcing bar cage is built into the shaft with the upper end of the flexible axial steel material held by a temporary ring, and the work is facilitated by removing the temporary ring and fixing the upper end to the column. become.

It is preferable that the column has a protrusion that protrudes laterally, and that the upper end of the axial steel member is fixed to the protrusion.
Construction is facilitated by fixing the upper end of the axial steel member to a protrusion such as a bearing plate or steel member that protrudes laterally from the column.

It is preferable that the reinforcing bar cage is vertically expandable and retractable, in which the axial steel material, the tie bars, and the temporary ring are rotatably joined.
A reinforcing bar cage, for example, is a structure in which axial steel is rotatably joined to stirrups or temporary rings, and the interval between the upper and lower stirrups increases or decreases as the intersection angle between the axial steel and the stirrups changes. , which realizes an elongated state in which the axial steel material is orthogonal to the stirrup bars, etc., and a contracted state in which the axial steel material is arranged at an angle and twisted in a spiral shape with respect to the stirrup bars, etc., and the use of such a reinforcing bar cage. This makes construction easier.

It is desirable that the column is a cylindrical socket into which the column can be inserted.
In this case, it is sufficient to construct a foundation by arranging relatively lightweight sockets, and then insert and fix the pillars into the sockets, which simplifies temporary fixing of the sockets and facilitates construction.

A second invention includes a reinforcing bar cage disposed in a shaft formed in the ground and an inclined column body, and a plurality of the reinforcing bar cages are arranged at intervals in the circumferential direction of the reinforcing bar cage. A flexible axial steel material is joined to circumferential straps of reinforcing bar cages arranged in multiple stages above and below, and the upper end of the axial steel material is bent and fixed to the column. , a concrete structure characterized in that the reinforcing bar cage and a fixed part in which the upper end of the axial steel member is fixed to the column are embedded in concrete.
The column is, for example, a cylindrical socket, and the column is inserted into the socket.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide a method for constructing a concrete structure, etc., which can be easily designed and constructed.

A diagram showing a foundation 100. A diagram showing a reinforcing bar cage 1. The figure which shows the construction method of the foundation 100. FIG. 6 is a diagram showing a method of fixing the upper end of the strand 11. An example in which bearing pressure plates 41 are provided in multiple upper and lower stages. The figure which shows the cylinder 42a and the washer 42b. The figure which shows the protruding board 41a. The figure which shows the plate-shaped rib 43 and the steel material 44. The figure which shows reinforcement rings 12a, 12b, and 12c. A diagram showing a socket 6.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

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

The foundation 100 is constructed by pouring concrete into a shaft 3 formed in the ground 2, and the reinforcing bar cage 1 is buried inside the concrete. Further, at the upper part of the foundation 100, a wrap-around concrete 102 is provided around the steel tower legs 4.

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

The reinforcing bar cage 1 has strands 11 and tie bars 12, and the upper end portions of the strands 11 are fixedly fixed to bearing plates 41 of the steel tower legs 4.

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

As described above, the reinforcing bar cage 1 has the strands 11 and the ties 12. The strands 11 are axial steel members of the reinforcing bar cage 1, and a plurality of strands are arranged at intervals in the circumferential direction of the reinforcing bar cage 1. The tie bars 12 are reinforcing bars provided in the circumferential direction of the reinforcing bar basket 1 so as to surround the strands 11, and are arranged in a plurality of upper and lower stages. The ties 12 and the strands 11 are rotatably joined at their intersections.

Furthermore, a temporary ring 13 is provided at the upper end of the reinforcing bar cage 1 in the circumferential direction of the reinforcing bar cage 1 so as to surround the strands 11 like the ties 12. The temporary rings 13 are arranged in multiple stages above and below the straps 12, and are rotatably joined to the strands 11 like the straps 12. Temporary ring 13 can be removed from strand 11. Note that the temporary ring 13 may be placed inside the strand 11 instead of outside, or may be placed both inside and outside the strand 11.

The strand 11 is made by twisting a plurality of PC steel wires and has flexibility. The reinforcing bar cage 1 is made by twisting the strands 11 in the circumferential direction of the reinforcing bar cage 1 as shown by arrow A in FIG. By changing the intersection angle of the reinforcement bars 12, etc. (the ties 12 and the temporary ring 13), the strands 11 are made into a spiral shape that is inclined with respect to the ties 12, etc., and the interval between the upper and lower ties 12, etc. is shortened to increase the total length of the reinforcing bar cage 1. can be reduced. On the other hand, by stretching the strand 11 in a straight line and eliminating the twist, the strand 11 and the stirrup bars 12, etc. intersect at right angles, and the spacing between the upper and lower stirrups 12, etc. returns to the original, and as shown in FIG. 2(a), the reinforcing bars It is possible to return the basket 1 to its original length.

(3. How to build basic 100)
Next, a method for constructing the foundation 100 using the reinforcing bar cage 1 will be explained with reference to FIG. 3 and the like.

As shown in FIG. 3(a), in this embodiment, a vertical shaft 3 is first formed in the ground 2.

Thereafter, as shown in FIG. 3(b), the reinforcing bar cage 1 is placed at the top of the shaft 3. The reinforcing bar cage 1 is tied down with a lashing material (not shown) such as a string to be in a contracted state, and the upper end and the lower end of the reinforcing bar cage 1 are each connected to a wire rod 5a, such as a wire, from separate hanging devices (not shown). 5b.

From this state, when the reinforcing bar cage 1 is unfastened and the wire rod 5b attached to the lower end of the reinforcing bar cage 1 is let out downward, the lower end of the reinforcing bar cage 1 extends downward. As a result, the reinforcing bar cage 1 expands as shown in FIG. 3(c), and the lower end of the reinforcing bar cage 1 reaches the bottom of the shaft 3. Alternatively, the secured reinforcing bar cage 1 may be lowered to the bottom of the shaft 3, the lashing may be released at the bottom, and the upper end of the reinforcing bar 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 manner, as shown in FIG. 3(d), the concrete of the foundation 100 is poured to a position below the temporary ring 13 in the middle of the shaft 3. Then, the temporary ring 13 is removed and the tower leg 4 is temporarily fixed on the top of the concrete as shown in FIG. 3(e), and the upper end of the strand 11 is bent as shown in FIG. 3(f). The upper end portion is fixedly fixed to the steel tower leg portion 4.

FIG. 4(a) is a diagram showing a method of fixing the strand 11. In this embodiment, an apartment 111 is provided at the upper end of the strand 11. The condominium 111 is a fixing part for fixing the upper end of the strand 11 to the bearing plate 41 of the steel tower leg part 4, and has a screw. By inserting this condominium 111 from below into a hole (not shown) provided in the bearing pressure plate 41 and screwing it into the nut 112 on the upper surface of the bearing pressure plate 41, the upper end of the strand 11 is fixedly fixed to the bearing pressure plate 41. Ru.

Here, the length by which the upper end of the strand 11 projects upward from the topmost hoop 12 varies 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 a position corresponding to the direction in which the tower leg 4 is inclined (corresponding to the right side in FIG. 3(e)) is smaller than that of the strand 11 at the opposite position.

The upper end of the strand 11 with a small protrusion length is fixed to the bearing plate 41 at a position corresponding to the direction in which the tower leg 4 is inclined (corresponding to the right side in FIG. 4(a)). The strand 11 with a large protrusion length is fixed to the bearing pressure plate 41 at the opposite position. This is preferable from the viewpoint of stress transmission between the steel tower legs 4 and the reinforcing bar cage 1 and workability, since no extra bending occurs in the strands 11.

Further, from the viewpoint of stress transmission, the strand 11 is arranged so as to have a straight portion B of a certain length parallel to the tower leg 4 below the bearing plate 41. In addition, in the example of FIG. 4(a), the bearing pressure plate 41 is provided so as to be perpendicular to the axial direction of the tower leg 4, but as shown in FIG. 4(b), the bearing pressure plate 41 is provided in the horizontal direction. You can. In the case of FIG. 4(a), it is easy to arrange the strand 11 in parallel with the tower leg 4, and in the case of FIG. can be made smaller.

After the upper ends of the strands 11 are fixed to the bearing pressure plate 41 in this manner, the formwork 5 for forming the neck-wrapping concrete 102 is placed as shown in FIG. 3(f).

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

As explained above, in this embodiment, the reinforcing bar cage 1 including the flexible strands 11 is used, and the upper end thereof is bent and fixed to the steel tower leg 4. Therefore, the steel tower legs 4 and the reinforcing bar cage 1 in the foundation 100 can be smoothly connected, and the joints will not be in a complicated stress state, making the design and construction easier. Further, the reinforcing bar cage 1 is built into the shaft 3 with the upper end of the flexible strand 11 held by the temporary ring 13, and the temporary ring 13 is removed and the upper end is fixed to the steel tower leg 4. This makes your work easier.

In particular, in this embodiment, the construction of the foundation 100 is facilitated by using the vertically expandable reinforcing bar cage 1 in which the strands 11 are rotatably joined to the ties 12 and the like.

Further, the upper end portion of the strand 11 is fixed to a bearing plate 41 that protrudes laterally from the steel tower leg portion 4, thereby facilitating construction.

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 pressure plates 41 may be provided above and below, and the upper ends of the strands 11 may be distributed and fixed to each bearing pressure plate 41.

The fixing positions of the strands 11 in the circumferential direction of the bearing pressure plate 41 are different between the upper and lower bearing pressure plates 41, and are changed, for example, in a staggered manner. In addition, the starting positions of the strands 11 are different in the vertical direction between the strands 11 fixed to the upper and lower bearing plates 41, as shown by C in the figure, and the stress transmission surface is such that the flexure of each strand 11 is made gentle. preferred.

Further, as shown in FIG. 6(a), when the tower leg 4 and the bearing plate 41 are perpendicular to each other, a cylinder 42a is provided that projects upward from the bearing plate 41 at the fixed position of the strand 11, and the upper surface of the cylinder 42a is By screwing the condominium 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. This makes it possible to reduce the difference in the length of the upper end of the strand 11 protruding from the strap 12, as in the example shown in FIG. 4(b).

In addition, as shown in FIG. 6(b), when the bearing plate 41 is provided in the horizontal direction, a washer 42b whose upper surface is inclined in a direction perpendicular to the tower leg 4 is provided, and the apartment 111 is attached to the nut 112 on the upper surface. They may be screwed together. 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 fixed as in the example of FIG. It becomes easier to form.

In addition, as shown in FIG. 7(a), instead of the ring-shaped bearing plate 41, independent protruding plates 41a (protrusions) are provided for each fixed position of each strand 11 so as to protrude outward from the tower legs 4. It may be provided. In this example, a plurality of protruding plates 41a protruding from the steel tower legs 4 in a direction orthogonal to each other are provided at the same height, and this results in a difference in the protruding length from the strap 12 at the upper end of the strand 11 described above. can be made smaller, and it is also easier to form the straight portion B of the strand 11 parallel to the tower leg 4.

Note that 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 can be inserted into the notch 411 from the side as shown by the arrow, which makes it easy to fix the condominium 111 to the protruding plate 41a', and the width of the notch 411 can be reduced. Such a notch 411 can also be applied to the bearing plate 41 described above and the steel material 44 described later.

In addition, as shown in FIG. 8, plate-shaped ribs 43 are provided that protrude laterally from the tower legs 4, and steel members 44 with an H-shaped cross section are fixed to both left and right sides of the plate-shaped ribs 43, and the upper ends of the strands 11 are attached to the horizontal portions of the plate-shaped ribs 43. It may be fixed. The plate-shaped rib 43 and the steel material 44 constitute a protrusion in the present invention.

Furthermore, the strand 11, which was straight in the shaft 3, becomes an S-shaped curve up to the bearing plate 41 of the inclined steel tower leg 4. When tensile force is generated in the strand 11 in a curved section of high-strength steel like the strand 11, a bearing force corresponding to the curvature is generated in the concrete on the inside of the curve. It is desirable to place reinforcing steel materials. That is, in this embodiment, it is desirable to arrange the reinforcing steel material inside the strand 11 in the lower part of the S-shaped section and outside the strand 11 in the upper part.

At this time, as shown in FIG. 9(a), in the upper part of the S-shaped section, reinforcement made of reinforcing steel material is placed so as to surround the straight portion of the strand 11 (see symbol B in FIG. 4(a)). 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 the upper end of the strand 11 is fixed to the bearing pressure plate 41. As shown in FIG. 9(b), the reinforcing ring 12a is tied in advance to the lower surface of the bearing pressure plate 41, and after fixing the upper end of the strand 11 to the bearing pressure plate 41, the reinforcement ring 12a is untied and moved downward in the shape of a blind. It is also possible to expand into

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. 9(a). For example, the reinforcing ring 12b can be tied in advance to the lower end of the steel tower leg 4, and after fixing the upper end of the strand 11 to the bearing pressure plate 41, it can be untied and unfolded upward in the shape of a blind. be.

In addition, in a general reinforced concrete bar member with a circular cross section, it is necessary to arrange band reinforcing bars so as to surround the axial reinforcing bars to withstand the shear force acting on the member, and in this embodiment as well, the shear force of the shaft 3 is It is desirable to arrange necessary reinforcing steel materials on the outside of the strand 11. The reinforcing ring 12c in FIG. 9(a) is provided as such reinforcing steel material, and is arranged outside the strand 11 at the lower part of the S-shaped section. As shown in FIG. 9(b), the reinforcing ring 12c is secured to the bearing pressure plate 41 in the same way as the above-mentioned reinforcing ring 12a, and can be unfolded downward in the shape of a blind.

Further, in this embodiment, the upper end of the strand 11 is fixed to the bearing pressure plate 41 of the tower leg 4, but instead, as shown in FIG. A bearing pressure plate 61 similar to the bearing pressure plate 41 may be provided in the socket 6 (column body), and the upper end portion of the strand 11 may be fixed to this bearing pressure plate 61.

In this case, after temporarily fixing the socket 6 and fixing the upper end of the strand 11 to the bearing plate 61 in the step shown in FIG. A foundation 100 is constructed by pouring concrete, and then the steel tower legs 4 are inserted and fixed into the sockets 6. Temporary fixation can be carried out using the relatively lightweight socket 6, which is lighter in weight than the tower leg 4, so that the construction can be easily performed. Furthermore, the members necessary for temporary fixing can be simplified and costs can be reduced.

In addition, unlike the tower legs 4, the sockets 6 can be temporarily fixed stably for a long period of time, so the sockets 6 are placed before concrete is poured into the shaft 3, and the upper ends of the strands 11 are fixed to the sockets 6. After the formwork 5 is installed, concrete may be poured into the shaft 3 and the formwork 5 at the same time. In this case, there is no need to pour concrete as described above, which contributes to improving the quality of the foundation 100.

Furthermore, in this embodiment, the length of the upper end of the strand 11 protruding from the hoop 12 is changed depending on the position in the circumferential direction of the reinforcing bar cage 1; The protrusion lengths may be the same. Alternatively, the length of the upper end of the strand 11 protruding from the tie bar 12 may be the same, and the length of the condominium 111 may be changed depending on the circumferential position of the reinforcing bar cage 1. 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 those skilled in the art can come up with various changes or modifications within the scope of the technical idea disclosed in this application, and these naturally fall within the technical scope of the present invention. Understood.

1: Rebar cage 2: Ground 3: Vertical shaft 4: Steel tower leg 5: Formwork 6: Socket 10: Foundation structure 11: Strand 12: Strap 13: Temporary ring 41, 61: Bearing plate 41a, 41a': Projecting plate 100: Basics 111: Apartment 112: Nuts

Claims (6)

A plurality of flexible axial steel members arranged at intervals in the circumferential direction of the reinforcing bar cage, circumferential reinforcing bars of the reinforcing bar cage arranged in multiple stages above and below, and reinforcing bars above the reinforcing bars. a step (a) of arranging a reinforcing bar cage, which is joined to a circumferential temporary ring of the reinforcing bar cage placed at the upper end of the cage, in a shaft formed in the ground;
(b) removing the temporary ring, bending the upper end of the axial steel member, and fixing the upper end to the inclined column;
has
A concrete structure characterized in that, by pouring concrete, a concrete structure is constructed in which the reinforcing bar cage and the fixed part of the upper end of the axial steel member fixed to the column are buried in concrete. Construction method. The column has a protrusion that protrudes laterally,
2. The method of constructing a concrete structure according to claim 1, wherein the upper end of the axial steel member is fixed to the protrusion. The concrete structure according to claim 1 or 2, characterized in that the reinforcing bar cage is vertically expandable and contractible by rotatably joining the axial steel material, the tie bars, and the temporary ring. How to build. 4. The method of constructing a concrete structure according to claim 1, wherein the column is a cylindrical socket into which a column can be inserted. A steel cage placed in a shaft formed in the ground,
a slanted column,
has
The reinforcing bar cage is made by joining together a plurality of flexible axial steel members arranged at intervals in the circumferential direction of the reinforcing bar cage and circumferential band bars of the reinforcing bar cage arranged in multiple stages above and below. and
The upper end of the axial steel member is bent and fixed to the column,
A concrete structure, characterized in that the reinforcing bar cage and a fixed part where the upper end of the axial steel member is fixed to the column are embedded in concrete. 6. The concrete structure according to claim 5, wherein the column is a cylindrical socket, and a column is inserted into the socket.

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