JP2947736B2 - Concrete columnar structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete columnar structure, and more particularly, to a concrete columnar structure constructed by using a plurality of frame-shaped precast forms mixed with a reinforcing material.

[0002]

2. Description of the Related Art Conventionally, most concrete structures are reinforced concrete structures. However, in the construction work, it takes a lot of time and labor to arrange the reinforcing bars before concrete is put on site, and in a high place and in a narrow place. There is also a problem with safety in the work.

[0003] Therefore, it is conceivable to use an easily assembled steel frame instead of a reinforcing bar and combine it with concrete to form a steel concrete structure. This has the advantage that cumbersome bar arrangement work can be largely eliminated.

On the other hand, by using a precast formwork, that is, a precast formwork that does not need to be removed, the work of removing and removing the concrete formwork at the site, assembling and removing the support materials, etc. is reduced, and the construction period is reduced. Can be shortened.

Therefore, if the structure to be constructed is a structure using both a precast formwork and a steel frame, it is possible to greatly simplify the work on site.

[0006]

However, in such a conventional concrete columnar structure, since the adhesion performance between the steel frame and the concrete is inferior to that of a different-diameter rebar, the dispersibility of cracks is poor as compared with a reinforced concrete structure. There was a disadvantage that the crack width was too large. For the same reason, there is also a problem that the deformation is excessive in the steel concrete structure as compared with the reinforced concrete.

[0007] Under such circumstances, there have been few examples of concrete structures constructed with a steel concrete structure. When a steel structure is used for a concrete structure, a steel reinforced concrete structure combined with a reinforcing bar is generally used.

[0008] The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a steel concrete structure capable of solving problems such as cracks and being widely applied to actual buildings and shortening the construction period. Making it a technical issue.

[0009]

The present invention has the following configuration in order to solve the above technical problems. In other words, the co
Steel built in connection with the foundation of concrete columnar structures
A bone and a composite in which the reinforcement is arranged via a reinforcement
It is formed by stacking a number of frames, through which a steel frame is inserted.
Precast formwork arranged to surround the steel frame of
The steel frame is cast into the precast
It consists of a concrete that to integrate the Yasuto type frame, before
The precast formwork is made of mortar and
Fiber, stainless fiber, aramid, vinylo
Selected from the group consisting of carbon fiber, carbon fiber, and glass fiber.
Or two or more reinforcing materials are mixed, and the steel frame is
Projections were formed on the surface .

[0010] By incorporating a reinforcing material into the precast formwork, the tensile strength of the precast formwork can be increased. Further, by using a steel frame having projections formed on the surface, the adhesion between concrete and steel frame can be improved. By improving the integrity, the crack width of the structure can be suppressed and the toughness can be improved.

In addition, since a precast formwork that does not need to be removed and a steel frame that is easy to assemble are used in combination, it is possible to greatly reduce labor on site. Hereinafter, each component will be described. [Precast formwork] This is usually manufactured in a factory and assembled on site. After the concrete has hardened, it is part of the structure without demolding. The surface may be decorated or left untouched. Since this is an industrial product, the durability and aesthetics of a structure constructed using the product can be improved at the factory manufacturing stage.

The base mortar of the precast mold is preferably a cement mortar having a water cement ratio of 20 to 60% (corresponding to claim 2). When a mortar having such a low water cement ratio is used, the resistance to corrosion factors such as salt, carbon dioxide, oxygen, and water is increased, and the durability of the structure can be improved.

At the time of assembling at a site or the like, a band reinforcing steel is attached to the inner surface of the precast form via a steel band fixing device while maintaining a predetermined distance from the inner wall of the precast form. In this way, it is possible to improve the covering accuracy and the positional accuracy of the belt reinforcing bar. [Steel Frame] The steel frame is preferably H-shaped, but other shapes such as L-shaped can also be used. This connects to a steel frame or anchor protruding from the upper surface of the foundation. In addition, continuous projections and depressions can be provided on the flange surface of the steel frame or the like to form the projections. The irregularities may be not only retrofitted ones but also irregularities formed on the surface at the manufacturing stage. [Reinforcing material] Steel fiber, stainless steel fiber, aramid, vinylon, carbon fiber, and glass fiber are used alone or in combination. Aramid is an aromatic polyamide fiber having a tensile strength of five times or more that of iron. As the carbon fiber, for example, a polyacrylonitrile-based one made of graphite-like carbon can be used.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. Here, the case where the structure is a pier will be described. Finally, a pier in which the surface of the precast form 1 is an outer wall is completed. First, the construction process will be described.

In the present embodiment, as shown in FIG. 1, a concrete precast material 7 formed in a cylindrical shape is used.
Is provided at the center of the portion surrounded by the precast formwork 1, and before the following construction is performed,
It is designed to be erected in the central part of. However, the installation of the precast material 7 is not an indispensable step, and may be provided after completion of the installation of the steel frame 4 described later.
The precast material 7 is formed in a circular shape with an inner diameter of 3.1 meters and a thickness of 0.1 meters.

The precast formwork 1 is made of an annularly formed precast concrete. The precast mold 1 is manufactured in advance in a factory, and is formed by connecting curved plates to form an integral annular body. Its cross section is circular, 4.5 meters in diameter, 2.5 meters in height and 5 cm in thickness. This precast form 1 has a water cement ratio of 20% to 60%.
As shown in FIG. 5, a reinforcing material 8 made of stainless steel was used at a volume ratio of 1%.
% To 4%.

The precast formwork 1 is suspended by a crane (not shown) by inserting a hook into a hole 36 at the tip of a suspension flat steel 35 (FIG. 3) provided on the inner surface thereof, and suspended by a crane (not shown). Stack one on top to get the desired height. Before or in parallel with this stacking operation, the reinforcing bars inside the precast formwork 1 are set up.

On the inner surface of the precast form 1, as shown in FIG. 4, fixing fasteners 5 a made of L-shaped steel are attached at intervals of 1.2 meters (so every other precast form 1). Installed. The belt reinforcing bar fixing tool 5a is fixed on a ring-shaped flat steel 37 provided at regular intervals on the inner circumference of the precast formwork 1. Assembled reinforcing bars 6 are attached to the belt reinforcing bar fixture 5a at predetermined intervals. As shown in FIG. 4, the rebar 6 is provided along the height of the pier. Then, the belt reinforcing bar 3 is attached to the assembled reinforcing bar 6 so as to be orthogonal thereto.
Are attached, and these form a grid. This steel bar 3
Are provided at intervals of approximately 15 cm in the height direction of the precast formwork 1 and are arranged as shown in FIG.

Before and after this step, the precast material 7
A steel frame 4 is erected around. A structure (not shown) equal to or more than the steel frame 4 is embedded in the foundation 2 as an anchor in advance, and the steel frame 4 is connected to this structure by bolting. Steel frame 4 is H steel (H-318 × 313 × 15 × 24)
And a projection (not shown) having a height of 2.1 mm and a pitch of 20 mm is provided on the flange surface in a direction perpendicular to the longitudinal direction to form irregularities on the surface.
Then, as shown in FIG. 1, the steel frame 4 is erected at a position where it does not come into contact with any of the strip reinforcing bar 3 and the precast material 7. The step of erecting the steel frame 4 may be performed before or after the step of stacking the precast formwork 1 or the step of setting the precast material 7 and before and after the construction.

By performing the above construction, a semi-finished state as shown in FIG. 2 is obtained. The precast mold 1 and the steel frame 4 are connected to a required number of steps to obtain a desired height. Thereafter, concrete is cast between the precast material 7 and the precast formwork 1. When the concrete hardens, the concrete pier is completed without removing the precast formwork.

The concrete pier thus constructed uses a precast formwork including a reinforcing material, and has a projection provided on a steel frame, so that the crack width can be reduced as shown in the following test example. It was possible to suppress it to the same level or less as that of reinforced concrete, and the amount of deformation was reduced. It is also expected to have excellent earthquake resistance.

Hereinafter, test examples will be described with reference to FIGS. [Test Example 1] A bending-shear test was performed on the steel precast concrete structure of the present invention, a conventional reinforced concrete structure, and a conventional steel frame concrete structure. (Specimen) As shown in FIG. 6, each specimen was a concrete beam 12 having a length of 4.6 meters, a width of 0.5 meters, and a height of 0.8 meters.

The test body 1 is a conventional reinforced concrete structure (RC), in which a belt reinforcing bar 11 is provided around a main reinforcing bar 10 as shown in FIG. Specimen 2 was a steel concrete structure (SC), and as shown in FIG.
3 are provided. Further, as shown in FIG. 9, the specimen 3 was a steel precast concrete structure (SC +
PCa), which uses a precast mold 12a and has four H steels 13 provided inside. (Test Method) In the test, two points 1.1 m inward were pressed from bearings provided at 0.4 m from both ends. (Test Results) (1) FIGS. 12 to 14 show the state of occurrence of cracks in specimens 1 to 3, respectively. In the drawing, the solid line indicates the state obtained when the tension-side reinforcing bar reaches the allowable stress, and the dotted line indicates the state generated when the tension-side reinforcing bar reaches the allowable stress to the yield stress, respectively.

The steel concrete structure according to the present invention has almost the same dispersibility of cracks as the reinforced concrete structure, and the reinforced precast concrete structure has little difference in allowable stress but cracks in the yield stress, compared with the other reinforced concrete structures. Is small. (2) FIG. 10 shows the relationship between the load of the test pieces 1 to 3 and the maximum crack width.

The specimen 3 has a smaller crack width than the specimen 1, and the steel frame precast concrete structure of the present invention has an effect of suppressing cracks. (3) FIG. 11 shows the relationship (toughness factor) between the load normalized by the yield load of the steel material and the displacement normalized by the yield displacement of the test specimen for the specimens 1 to 3.

From this graph, it can be seen that the toughness of the steel precast concrete structure exceeds that of the reinforcing steel or concrete structure. Test Example 2 Positive and negative alternating loading tests were performed on the steel frame precast concrete structure of the present invention and a conventional reinforced concrete structure. (Specimen) As shown in FIG. 15 for each specimen, a hollow cylindrical column 21 having a diameter of 0.9 m, an inner diameter of 0.3 m, and a height of 2.6 m was placed on a base 20 having a height of 0.75 m. Was formed.

FIG. 17 is a sectional view of the test piece 4 having a reinforced concrete structure. This is provided with a main reinforcing bar 22 therein and a band reinforcing bar 24. FIG. 18 is a cross-sectional view of a test body 5 having a steel precast concrete structure, in which eight H steels 23 are provided inside and a steel bar 25 is provided. (Test Method) An axial force loading jack 30 is provided on the upper surface of the test body, and a PC steel rod 31 is hung from the jack 30 and the lower end thereof is connected to an anchor 32 embedded and fixed in the base 20. . An actuator 38 is provided between the upper end stub 33 and the reaction wall 34, and one end of the actuator 38 is connected to the stub 33.
It is fixed to.

In such a state, the axial load jack 3
By applying a predetermined axial force to the entire test piece by pulling the PC steel rod 31 by 0, the actuator 38 was operated to repeatedly apply a horizontal positive / negative force to the stub 33 portion. (Test Results) FIG. 18 shows the horizontal displacement of the loading point of the test piece 4 and FIG. 19 shows that of the test piece 5. The vertical line indicates the load (ton), the horizontal line indicates the horizontal displacement of the loading point in millimeters, and the dotted line indicates the calculated value of the ultimate proof stress.

FIG. 20 shows the relationship between the load and the displacement (envelope) of the specimen 4 and the specimen 5, and the vertical axis represents the load (t),
The horizontal axis is the loading point horizontal displacement. According to the above results, the test specimen 4 and the test specimen 5 show almost the same deformation performance, and the test specimen 5 shows toughness higher than that of the test specimen 4.
From the above, it can be seen that the structure of the present invention has the deformation performance not inferior to the conventional reinforced concrete structure, and has toughness higher than that of the conventional reinforced concrete.

[0030]

According to the present invention, since a reinforcing material is mixed into a frame-shaped precast mold and a steel frame having projections is used, the crack dispersibility and toughness of the steel concrete structure are greatly improved. You. By stacking such frame-shaped precast forms to form a concrete columnar structure, there is an effect that the construction period can be shortened.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a pier that is a steel concrete structure of the present invention.

FIG. 2 is a perspective view showing the structure of a pier which is a steel concrete structure of the present invention.

FIG. 3 is a schematic view showing a precast formwork to which a band reinforcing bar is attached.

FIG. 4 is a side view showing a precast formwork to which a band reinforcing bar is attached.

FIG. 5 is a partial cross-sectional view of a precast mold in which a reinforcing material is mixed.

FIG. 6 is a side view showing a test body used in Test Example 1.

FIG. 7 is a sectional view of a test piece 1 used in Test Example 1.

FIG. 8 is a sectional view of a test body 2 used in Test Example 1.

FIG. 9 is a sectional view of a test body 3 used in Test Example 1.

FIG. 10 is a diagram showing a relationship between a load and a crack width in Test Example 1.

FIG. 11 is a diagram showing the relationship between load and displacement in Test Example 1.

FIG. 12 is a diagram showing a crack state of a test piece 1 in Test Example 1.

FIG. 13 is a view showing a crack state of a test body 2 in Test Example 1.

FIG. 14 is a view showing a crack state of a test piece 3 in Test Example 1.

FIG. 15 is a view showing a test body of Test Example 2 and an implementation method.

FIG. 16 is a cross-sectional view showing the structure of the test body 4.

FIG. 17 is a cross-sectional view showing a structure of a test body 5.

FIG. 18 is a graph showing horizontal displacement of a specimen at a loading point.

FIG. 19 is a graph showing horizontal displacement of a specimen 5 at a loading point.

FIG. 20 is a graph showing a relationship between a load and a displacement of the test body 4 and the test body 5;

[Explanation of symbols]

 1. Precast formwork 2. Foundation 3. Band reinforcement 4. Steel frame 5. Concrete 8. Reinforcement

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazunori Kono 2-10-26 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industries Co., Ltd. (72) Inventor Tetsuya Mishima 2- 10-26 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industry Co., Ltd. (72) Inventor Natsuo Hara 2--10-26 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industry Co., Ltd. (72) Inventor Hideko Imanishi 2- 10-26, Fujimi, Chiyoda-ku, Tokyo Maeda Construction (72) Inventor Osamu Hashimoto 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Kawasaki Steel Corporation (56) References JP-A-7-90980 (JP, A) JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) E04C 3/00-3/46 E01D 1/00-23/00

Claims (2)

(57) [Claims] 1. Connecting to the foundation of a concrete columnar structure
Built-in steel frames and multiple frames with strip reinforcement inside through strip reinforcements
It is formed by stacking the bodies, and the steel frame is inserted
A precast formwork arranged to surround the
Poured into a recast formwork and precast with the steel frame
It is made of concrete that integrates with the formwork.
The cast form is made of mortar, steel fiber
ー, stainless fiber, aramid, vinylon, carbon
One or more selected from the group of fibers and glass fibers
The above reinforcing material is mixed in, and the steel frame
Concrete characterized by the fact that it is formed
Columnar structure . 2. The concrete columnar structure according to claim 1, wherein said concrete columnar structure is a concrete pier.