WO2001020089A1

WO2001020089A1 - Concrete structure and method of constructing the same

Info

Publication number: WO2001020089A1
Application number: PCT/JP1999/004954
Authority: WO
Inventors: Kazunori Kono; Hidekimi Imanishi; Minoru Tabata; Tatsuya Ueda
Original assignee: Maeda Corporation
Priority date: 1999-09-10
Filing date: 1999-09-10
Publication date: 2001-03-22

Abstract

A concrete structure capable of reducing a construction term by omitting reinforcement fabricating and form removing operations in construction work, and of securing the safety of the work; and a method of constructing the same. The method comprises forming a basis by building steel frames to a predetermined height, forming frame type form members in which reinforcements are arranged via reinforcement fixing members, piling up a plurality of form members so as to enclose the steel frames therewith, placing concrete in a precast form formed of the piled form members, and uniting in a body the steel frames, tie hoops and precast form by curing the concrete.

Description

Description Title of the invention Concrete structure and method for constructing the same Technical field

TECHNICAL FIELD The present invention relates to a steel-frame concrete structure, and more particularly to a concrete structure excellent in quickness and safety of construction and a method of constructing the same. Background technology

Conventionally, most concrete structures are reinforced concrete structures, but in the construction work, it takes a great deal of time to rebar the concrete before placing the concrete, and it is safe to work in high places and in narrow places. There is also a problem.

The conventional construction method is as follows. First, a number of main reinforcing bars are erected from the foundation, and the belt reinforcing bars are fixed so as to surround the main reinforcing bars. When fixing the belt reinforcing bar, it is fixed to the main reinforcing bar manually using a binding wire or the like.

After such reinforcement work is completed, a concrete formwork is set up around the rebar by attaching supports. After completion of the formwork, concrete is poured into the formwork, and after curing, the formwork and support are dismantled and removed. A series of operations consisting of such steps are repeatedly performed as many times as necessary.

However, such a construction method has the following problems.

Firstly, assembling the rebar requires a lot of time and effort, and requires a lot of labor and labor, so the period is long.

Secondly, it is necessary to remove the concrete formwork and dismantle the support, which requires labor and a temporary installation place for the formwork.

Third, assembling the rebar may be a work at height, which reduces safety and workability.

On the other hand, it is conceivable to use steel frames that are easy to assemble instead of reinforcing bars, and combine them with concrete to form a steel frame concrete structure. However, in steel-framed concrete structures, the adhesion between steel frames and concrete is inferior to that of steel bars. Cracks have poor dispersibility compared to reinforced concrete structures, and have the disadvantage of excessive crack width. For the same reason, there is also a problem that the deformation of the steel concrete structure is excessive compared to the reinforced concrete.

Under such circumstances, when steel frames are used for concrete structures, rebars are also used, and it is inevitable that complicated rebar arrangement work is involved.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a concrete structure and a method of constructing a concrete structure that can easily assemble a reinforcing bar and can shorten a period by removing a mold. To provide.

Another object of the present invention is to provide a method for constructing a concrete structure capable of ensuring work safety and improving the covering accuracy of concrete and the assembling accuracy of reinforcing bars. Disclosure of the invention

The present invention provides a step of forming a foundation by building a steel frame to a required height, a step of forming a frame-shaped form member in which a reinforcing bar is arranged via a reinforcing bar mounting tool, and surrounding the steel frame. Stacking a plurality of form members as described above, and placing concrete in a precast form formed by the stacked form members and hardening the same to integrate the steel frame, the band reinforcing bar, and the precast form. This is a method of constructing a concrete structure with and.

Reinforcing bars can be arranged by a method of arranging a reinforcing bar assembly on the inner surface of the form member and fixing the reinforcing bar to the reinforcing bar assembly.

Further, inside the form member, a reinforcing bar and a steel material are arranged so as to be alternately stacked with a space therebetween, and the reinforcing bar is fixed to a reinforcing bar assembly material arranged on the inner surface of the form member, and the steel material is a formwork. It may be fixed in the transverse direction of the member. In this case, the steel member protects the formwork member from deformation due to external pressure. Therefore, in the work of stacking the form members, the form members are prevented from being deformed.

As the reinforcing bar, a band reinforcing bar and an intermediate reinforcing bar can be used.

The band reinforcement is also called a shear reinforcement and has a bar-shaped or plate-shaped cross-section. Since the reinforcement is installed away from the side of the formwork, it is desirable to fix the reinforcement through a band reinforcement. band Casting concrete without placing the rebar in contact with the steel (steel or rebar) installed inside.

For example, an L-angle, small H steel, or the like can be used as the band reinforcing bar, and supports the band reinforcing bar and forms an appropriate gap between the formwork and the band reinforcing bar. After casting concrete, this gap becomes concrete cover.

The steel frame is preferably an H-beam, but other shapes such as an L-beam may be used, which connect to a steel frame or anchor protruding from the top surface of the foundation. In addition, if projections are provided on the flange surface of steel frame, etc., the adhesion of concrete is improved, and the integrity with concrete is obtained. This projection may be formed on the surface in the manufacturing stage, not to mention a post-installed one.

By using a steel frame with projections on the surface in this way, it is possible to suppress the crack width of the structure and improve the toughness

Further, when the concrete structure is hollow, the precast formwork is constituted by a precast outer frame member arranged outside the steel frame, and a precast inner frame member arranged on the 內 side of the steel frame. The concrete frame can be built by attaching the frame for use and the reinforcing bar to one or both of the precast outer frame member and the precast inner frame member.

The form member is usually manufactured in a factory or the like and assembled on site. After the cast-in-place concrete is hardened, it will be part of the structure without demolding. The surface may be decorated or left alone. Since this formwork member is an industrial product, it is possible to secure the durability of the structure constructed using the formwork member and to improve the appearance at the factory manufacturing stage.

The mold member may a water-cement ratio Ca ^s 2 ^0~ 6 0% of cementitious mortars and child. When a mortar having such a low water cement ratio is used, resistance to corrosion factors such as salt, carbon dioxide, oxygen, and water is increased, and the durability of the structure can be improved.

Further, as the mortar mold member, one containing one or two or more reinforcing materials selected from the group consisting of steel fiber, stainless fiber, aramid, vinylon, carbon fiber, and glass fiber is preferably used. Can be Aramid is aromatic It is a polyamide fiber and has a tensile strength more than 5 times that of iron. As the carbon fiber, for example, a polyacrylonitrile-based carbon fiber made of graphite-like carbon can be used. By incorporating such a reinforcing material, the tensile strength of the precast formwork can be increased, and by using a steel frame with projections formed on the surface, the adhesion and integrity of the concrete and steel frame can be improved. And the crack width of the structure can be suppressed and the toughness can be improved.

When the form member reinforced as described above is used, problems such as a large crack width, which is a problem in the steel frame concrete structure, and excessive deformation can be solved.

If a concrete formwork that does not need to be removed and a steel frame that is easy to assemble are used together, the labor at the site can be greatly reduced. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view of a pier constructed by the method of the present invention.

FIG. 2 is a perspective view showing a semi-finished state of a pier constructed by the method of the present invention. FIG. 3 is a diagram showing a part of the inner side surface of a form member to which a band reinforcing bar is attached.

FIG. 4 is a side view of a form member to which a band reinforcing bar is attached.

FIG. 5 is a conceptual diagram of a form member to which a reinforcing material is added.

FIG. 6 is a flowchart showing a construction order in the second embodiment.

FIG. 7 is a sectional view of a pier according to the second embodiment.

Figure 8 is a diagram showing the installation of a steel frame.

FIG. 9 is a cross-sectional view showing a state in which footing has been formed.

FIG. 10 is a cross-sectional view showing a step of stacking the form members.

FIG. 11 is a cross-sectional view showing a state in which concrete has been poured into formwork 內 to form the foundation of the pier.

FIG. 12 is a cross-sectional view showing a state where a steel frame is added.

FIG. 13 is a cross-sectional view showing a state in which mold members are stacked on a foundation.

FIG. 14 is a cross-sectional view showing a state in which the precast inner forms are stacked.

FIG. 15 is a cross-sectional view showing a state in which reinforcing bars are arranged. FIG. 16 is a cross-sectional view showing a state in which a concrete is cast in a Brecast formwork.

Figure 17 is a cross-sectional view of the completed pier.

FIG. 18 is a diagram showing a state where a mesh reinforcing bar is fixed to the inner frame.

FIG. 19 is a diagram showing a state in which a belt reinforcing bar is fixed to the inner frame.

FIG. 20 is a diagram showing a state where the outer frame is attached.

FIG. 21 is a diagram showing a state where a reinforcing bar is attached to the outer frame.

FIG. 22 is a diagram showing a state where an intermediate reinforcing bar is attached.

FIG. 23 is a flowchart showing a construction order in the third embodiment.

FIG. 24 is a diagram showing the construction order in the third embodiment.

(b) is the footing construction, (c) is the installation of formwork members, (d) is the placement of concrete, and (e) is the diagram showing the completed pier.

FIGS. 25A and 25B are views showing a mold member, wherein FIG. 25A is a plan view thereof, FIG.

(c) is a side view thereof.

Fig. 26 is a diagram showing the order of assembling the reinforcing steel and copper material in the formwork member, (a) showing the state where the steel material is arranged inside, and (b) showing the state where the reinforcing steel is fixed to the steel material. Figure showing

(c) is a diagram showing a state in which a shape-retaining steel material is arranged, and (d) is a diagram showing a formwork member completed by laminating a reinforcing bar and a steel material.

FIG. 27 is a perspective view of a pier in the middle of construction according to the third embodiment.

FIG. 28 is a diagram showing the position of the load P in Test Example 1.

FIG. 29 is a cross-sectional view of the specimen 1.

FIG. 30 is a cross-sectional view of the test piece 2.

FIG. 31 is a cross-sectional view of the test piece 3.

FIG. 32 is a diagram showing cracks of the test piece 1 to which the load P is applied.

FIG. 33 is a diagram showing cracks of the test piece 2 to which the load P is applied.

FIG. 34 is a diagram showing cracks of the test piece 3 to which the load P is applied.

Fig. 35 is a diagram showing the crack width of the test pieces 1 to 3 in the bending-shear test. _C Fig. 36 is a view showing the toughness factor of the test pieces 1 to 3 in the bending-shear test. FIG. 37 is a cross-sectional view showing the structure of the test piece 4. As shown in FIG. FIG. 38 is a cross-sectional view showing the structure of the test piece 5. As shown in FIG.

FIG. 39 is a diagram showing an apparatus for performing Test Example 2.

FIG. 40 is a diagram showing the horizontal displacement of the specimen 4 at the unloading point.

FIG. 41 is a diagram showing the horizontal displacement of the specimen 5 at the unloading point.

FIG. 42 is a diagram showing the relationship between the load and the displacement of the test pieces 4 and 5. BEST MODE FOR CARRYING OUT THE INVENTION

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

(Example 1)

An embodiment of the present invention will be described with reference to FIGS. Here, the case where a concrete structure is used as a pier will be described.

As shown in FIG. 1, a plurality of annular formwork members 1 are stacked to form a pier A in which the surface of the precast formwork 9 becomes an outer wall. First, the construction process will be described.

In this embodiment, a cylindrical precast material 7 made of concrete is provided inside the laminated annular form member 1. The precast material 7 and the steel frame 4 are erected in the center of the foundation 2 before performing the following construction. However, the installation of the precast material 7 is not an indispensable process, and may be performed after the completion of the steel frame 4 to be described later. The inner diameter of the precast material 7 is 3.1 meters, and the thickness is 0.1 meters.

The form member 1 is manufactured in advance in a factory, and is formed by joining 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. The form member 1 is a cement-based mortar having a water-cement ratio of 20% to 60%, and as shown in FIG. % It is mixed.

Further, as shown in FIGS. 3 and 4, the mold member 1 is provided with vertical copper bars 35 for suspension at predetermined intervals on the inner peripheral surface thereof. A hole 36 is provided at the tip of the flat steel 35, a hook is passed through the hole 36, and the hook is suspended by a crane (not shown). W 1 „It is possible to sequentially stack them on the foundation 2. By stacking a plurality of form members 1, a concrete form A having a desired height can be obtained.

Before or concurrently with the stacking work of the formwork member 1, the reinforcing bars inside the formwork member 1 are set up.

Reinforcing bars are arranged as follows. As shown in FIG. 4, mounting strip reinforcing bars 5a made of an L-shaped steel material are attached to the inner surface of the mold member 1 at intervals of 1.2 meters. The belt reinforcing bar fixing device 5 a is fixed on a ring-shaped horizontal flat steel 37 provided at regular intervals in the inner circumferential direction of the form member 1. As shown in FIG. 4, assembled reinforcing bars 6 are attached to the belt reinforcing bar fixture 5a at predetermined intervals in the height direction. The strip reinforcing bar 3 is attached horizontally so as to be orthogonal to the assembled reinforcing bar 6, and the reinforcing bars are arranged in a lattice shape. The reinforcing bars 3 are provided at intervals of about 15 cm. Before or after this step, a steel frame 4 is erected around the precast material 7. A structure (not shown) equal to or more than the steel frame 4 is embedded in the base 2 as an anchor in advance, and the steel frame 4 is connected to this structure by bolting. The steel frame 4 is made of H copper (H-318 x 3 13 x 15 x 24), and its flange surface has a height of 2.1 mm and a pitch of 20 mm in the direction perpendicular to the longitudinal direction. Protrusions are formed on the surface to provide projections. 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 band reinforcing bar 3 and the precast material 7. The process of erecting the steel frame 4 does not matter before or after the process of stacking the formwork member 1 or the process of setting the precast material 7 and before and after the process.

When the above construction is completed, the pier will be in a semi-finished state as shown in Figure 2. In this step, the required number of form members 1 and steel frames 4 are connected to each other to obtain a desired height. Then, a concrete is cast between the precast material 7 and the stacked formwork members 1. When the concrete hardens, the concrete pier is completed without removing the precast formwork 9.

The concrete pier A constructed in this way uses the precast formwork 9 and also has a projection on the steel frame, so that the crack width is about the same as or less than that of the reinforced concrete structure. As a result, the amount of deformation of the pier was reduced. It is also expected to have excellent earthquake resistance. (Example 2)

FIG. 6 is a flowchart showing a method of constructing a concrete pier. First, the construction order will be described based on this flowchart.

In this construction, first, a required number of frame-shaped form members 10 are formed in an assembly yard or a manufacturing factory (step 1). Next, the belt reinforcing bar 11 is attached to these form members 10 via the reinforcing bar frame 14 shown in FIG. 7 (step 2). In parallel with or after steps 1 and 2 above, a steel frame 12 such as an H-beam is erected at the concrete pier 1 construction site (step 3). A precast form member 10 is set around the steel frame 12 (step 4). Then, a support (not shown) is assembled (step 5).

Hereinafter, by repeatedly performing the above-described installation of the form member 10 in step 4 and the assembling of the support in step 5 a predetermined number of times, the precast form members 10 are sequentially stacked to a predetermined height. To

Next, concrete 13 is poured into the stacked precast form members 10 (step 6).

In this way, after a part of concrete pier B (see Fig. 7) has been constructed to the specified height, the above-mentioned step 3 of setting up the steel frame 12 and the concrete placing of step 6 are repeated a predetermined number of times n. By doing so, concrete pier 1 is completed (step 7).

In the case of a relatively low concrete pier, the steel frame 12 is made into one step, a predetermined number of form members 10 are stacked around the steel frame 12, and then concrete 13 is poured into the concrete pier. Can be completed. This is the case where n is 1 as described above.

Figure 7 shows a cross section of a concrete pier B constructed by applying the above construction method. The form member 10 of the concrete pier B is a frame-shaped, in this embodiment, a quadrilateral precast outer frame member 10a, and a precast frame member 1 arranged on one side of the precast outer frame member 10a. A predetermined number of H-shaped steel frames 12 are arranged between the precast outer frame member 10a and the precast frame member 10b. The outer cast frame member 10a and the precast frame member 10b serve as the outer walls of the concrete pier B, and are formed in a rectangular shape by concrete or mortar. The precast outer frame member 10a and the precast frame member 10b are divided into a plurality of pieces in advance in an assembly card manufacturing plant or the like as described above, and these divided pieces are connected to form an integrated body. It can be formed as a frame. The cross-sectional shape is a quadrangle in the present embodiment, but may be any shape such as a circle, an ellipse, and a polygon. Further, in the present embodiment, a plurality of reinforcing steel frames 14 are provided at appropriate intervals on the outer peripheral side of the precast inner frame member 10b, and the belt reinforcing steel 11 is attached to these reinforcing steel frames 14. I have. The structure and mounting method of the reinforcing bar frame 14 and the belt reinforcing bar 11 will be described later.

Fig. 8 to Fig. 17 show the construction procedure of the concrete pier B mentioned above. It is assumed that the mold member 10 is manufactured in advance. Here, first, as shown in Fig. 8, the anchoring portion of steel frame 12 such as H-shaped copper is erected on the foundation step 21 of concrete pier B. Next, as shown in FIG. 9, a concrete for forming the fitting 22 is cast. Subsequently, as shown in FIG. 10, a predetermined number, in this embodiment, two, of the precast outer frame members 10a are stacked and installed on the fitting 22. After that, as shown in Fig. 11, if concrete 13 is poured into the stacked precast outer frame members 10a, 10a, the solid part which becomes the foundation of the concrete pier B is completed.

Next, as shown in FIG. 12, a steel frame 12 is further added to the steel frame 12 and connected by a connecting means such as a bolt. Subsequently, a predetermined number of precast outer frame members 10a are additionally placed on the precast outer frame members 10a already installed as shown in FIG. 13, and then, as shown in FIG. A precast inner frame member 10b is stacked inside by a certain number and placed inside 12. A strip reinforcing bar 11 is attached to the precast frame member 10b as described later.

Next, as shown in FIG. 15, the precast outer frame member 10a and the precast inner frame member 10b are connected by, for example, a bar-shaped connecting member 24. The connecting member 24 can be made of a steel material such as an equilateral mountain steel or a groove steel other than the rod-shaped member. By connecting with the connecting member 24 in this way, it is possible to prevent the precast outer frame member 10a, the precast / frame member 10b force S, and the lateral pressure caused by the concrete 13 from bending. Next, As shown in 16, concrete 13 is cast between the precast outer frame member 10a and the precast inner frame member 10b.

In the same way, by repeatedly installing the steel frame 12, installing the precast outer frame member 10a and the precast frame member 10b, and pouring concrete 13 in the same manner, Figure 17 As shown, concrete pier B can be completed.

FIG. 18 to FIG. 22 show a procedure for attaching the above-described reinforcing bar frame 14 and reinforcing bar 11 to the precast inner frame member 10b. Here, a description will be given of a case where the reinforcing bar frame 14 is a quadrangle and is vertically divided into two. First, as shown in FIG. 18, one inner frame 14a of the reinforcing bar frame 14 is fixed to the outer peripheral surface of the precast inner frame member 10b by an appropriate method. The inner frame 14a has a U-shape, and mesh streaks 25 are provided on the vertical sides. The mesh bars 25 are attached to maintain the pitch of the band reinforcing bars 11 accurately and to facilitate the assembly of the band reinforcing bars 11.

Next, as shown in FIG. 19, a plurality of belt reinforcing bars 11 are attached to the mesh bars 25. Subsequently, the other outer frame 14b is attached to the inner frame 14a as shown in FIG. The outer frame 14 b is also provided with a mesh streak 26. Next, as shown in Fig. 21, the strip reinforcing bar 11 is attached to the mesh bar 26 of the outer frame 14 b, and as shown in Fig. 22, the strip reinforcing bar 11 of the upper frame 14 a is The intermediate reinforcing bar 27 is connected to the belt reinforcing bar 11 of the outer frame 14 b. This completes the installation of the reinforcing bar frame 14, the belt reinforcing bar 11 and the intermediate reinforcing bar 27.

The method for constructing a concrete pier according to the present invention is as follows. Since the reinforcing bar 11 is previously attached to the inner frame member 10b, which is the form member 10, via the reinforcing bar frame 14 and then piled up. Installation of 1 becomes easy. In addition, since it is not necessary to assemble the rebar 11 and disassemble the formwork at the site, it is possible to reduce the number of work steps and the time required for delivery. In addition, rebar assembly work at high places is omitted, and work safety is improved.

In addition, a reinforcing bar frame 14 is provided on the precast inner frame member 10b, and the reinforcing bar 11 is mounted on the inner frame 14a of the reinforcing bar frame 14, so that the mounting of the reinforcing bar 11 is easy. Become. By providing this reinforcing bar frame 14, When lifting the _n -type form 10, it is difficult to deform, and the predetermined shape can be maintained. Although the reinforcing bar frame 14 and the band reinforcing bar 11 are attached to the precast frame member 10b in the present embodiment, they can be attached to the precast outer frame member 10a. Further, the step of installing the form member 10 and the step of erection of the steel frame 12 can be replaced with each other as appropriate.

(Example 3)

FIG. 23 is a flowchart showing a method of constructing a concrete leg according to the third embodiment. First, an outline of the construction will be described based on this flowchart and FIG. In the construction of footing 22, the pier construction site is excavated, a plurality of steel frames 12 such as H-beams are erected, and concrete is cast to form the foundation of pier C.

The assembling of the formwork member 10 is performed in parallel with the work of the footing 22, which is performed in a factory or a yard near the construction site. Predetermined reinforcing bars and copper materials are arranged inside the formwork member 10 to manufacture the required number of pieces for construction.

In the construction of pier C, formwork members 10 are sequentially stacked from below along steel frames 12. After forming the precast form 9 by fastening the form members 10 together with bolts or the like, concrete is poured into the precast form 9 through a concrete pumping pipe P from a pump truck. This work is required n times! : Repeat and build the pier C to the specified height to complete the construction.

Hereinafter, each step will be described in more detail with reference to FIGS.

(Construction of footing)

As shown in Fig. 24 (a), at the construction site of concrete pier C, ground G is excavated to a predetermined depth. 10 H-beams 12 are erected on the excavated surface and inside the formwork members. A reinforcing bar (not shown) is arranged around the H-shaped steel 12 and a concrete formwork is assembled and arranged around the H-shaped copper 12 and the reinforcing bar. Pour concrete. For the steel frame 12, an H-section steel with a protrusion formed on the flange is used.

As shown in Fig. 24 (b), when the concrete hardens and the fitting is formed, the excavated part is backfilled.

(Assembly of form members) _i2 At the same time as the above-mentioned fitting, the required number of frame-shaped form members 10 shown in Fig. 25 are formed in a place other than the construction site, for example, in an assembly yard ゃ a manufacturing factory (step 1). ). The form member 10 is a rectangular frame having a short side to long side ratio of about 1: 2, and is formed with a predetermined height.

A belt reinforcing bar 11 is attached to these precast form members 10 via a reinforcing steel assembly 40 (step 2). The steel rebar assembly steel material 40 is a channel steel or an angle steel that is disposed at a predetermined interval on the inner peripheral surface of the frame-shaped form member 10. The rebar-assembled steel materials 40 are provided at eight locations at predetermined intervals in the vertical direction with respect to the form member 10. The frame-shaped reinforcing bar 11 is fixed to the reinforcing steel assembly 40 by welding or the like, and crosses the reinforcing bar 11 and intersects with the reinforcing bar 11 in a grid pattern. Distribute. The strip reinforcing bar 11 and the intermediate reinforcing bar 27 may be assembled as a single unit, or those previously assembled in a rice cake net shape may be fixed to the reinforcing bar assembled steel material 40.

The frame-shaped portion forming the form member 10 is assembled by joining the U-shaped body 43 at the end and the linear body 44 connecting the two U-shaped bodies. To join them, a joint steel member 42 is provided in contact with the reinforcing steel member 40, and the reinforcing steel member 40 and the joint steel member 42 are fastened to each other by bolts.

On the other hand, one shape-retaining steel material 41, which is a channel steel or an angle iron, is arranged in the longitudinal direction of the formwork member, and three in the lateral direction. These are arranged so as to be alternately stacked with the above-mentioned belt reinforcing bars 11 and intermediate reinforcing bars 27 as shown in FIG. 26 (d).

Note that, as shown in FIG. 27, the strip reinforcing bar 11 and the like and the shape-retaining steel material 40 are arranged at positions where they do not come into contact with the H-shaped steel when the form members 10 are stacked.

The shape-retaining steel material 41 is arranged in the transverse direction of the form member 10 to prevent both deformation of the form member 10 at the time of lifting and deformation due to lateral pressure at the time of placing concrete, and the latter is generally used in concrete. It will perform the same function as the separator used for a single formwork.

(Construction of pillar)

Next, as shown in FIGS. 24 (c) to (d), the precast form members 10 are sequentially stacked around the steel frame 12 to a predetermined height, and the stacked precast Pour concrete 13 into form member 10.

In this way, after constructing a part of the concrete pier C to a predetermined height, the scaffold 14 is installed on the uppermost formwork member, and the above-mentioned work (for the formwork member 10 The concrete pier C is completed by repeating the installation and concrete casting) a predetermined number of times n. In the case of a relatively low concrete pier, the concrete pier C is completed by stacking all the form members 10 around the steel frame 12 and then placing the concrete 13 thereon.

The cross-sectional shape of the form member 10 is substantially quadrangular in this embodiment, but may be any shape such as a circle, an ellipse, or a polygon according to the cross-sectional shape of the pier.

(Test Example 1)

In order to compare the concrete structure of the present invention with conventional reinforced concrete structures and steel-frame concrete structures, bending and shear tests were performed on these structures. (Specimen)

As shown in Fig. 28, each of the specimens is a concrete beam with a length (L) of 4.6 m, width (W) of 0.5 m, and height (H) of 0.8 meter. 120. Specimen 1 has a conventional reinforced concrete structure (R C). As shown in FIG. 29, a belt reinforcing bar 110 is provided around the main reinforcing bar 100. Specimen 2 has a steel frame concrete structure (S C), and is provided with four H-section steels 130 as shown in FIG. Further, as shown in FIG. 31, the specimen 3 has a steel frame precast concrete structure (SC + PCa) of the present invention, and has a precast formwork 120a on a side surface and four insides. H steel 130 is provided.

(Test method)

In the test, from the bearings 121 provided at a position of 0.4 m from both ends, a point 122 inside each 1.1 m was pressed by a load P.

(Test results)

(1) Figure 32 through Figure 34 show the state of occurrence of cracks in specimens 1 through 3. In the figure, the solid line shows the cracks when the tension-side reinforcement reaches the allowable stress, and the dotted line shows the cracks when the tension-side reinforcement gives the allowable stress to the yield stress. The steel frame precast concrete structure of the present invention has almost the same dispersibility of cracks as the reinforced concrete structure.Also, the structure of the present invention has little difference in allowable stress but cracks in yield stress compared to other structures. I understood that there were few.

(2) Figure 35 shows the relationship between the load on specimens 1 to 3 and the maximum crack width. Specimen 3 has a smaller crack width than Specimen 1, and the steel frame precast concrete structure of the present invention has an effect of suppressing cracking.

(3) For specimens 1 to 3, the relationship between the load normalized by the yield load of steel and the displacement normalized by the yield displacement of the specimen (toughness factor) is shown in Fig. 36.

From these results, it is understood that the toughness of the steel frame precast concrete structure of the present invention exceeds that of the steel bar or the steel frame concrete structure.

(Test Example 2)

Positive and negative alternating load tests were performed on the steel frame precast concrete structure and the reinforced concrete structure of the present invention.

(Specimen)

Specimen 4 is a reinforced concrete structure as shown in Figure 37. The main reinforcement 220 and the belt reinforcement 240 are arranged inside this, and the center is hollow.

Specimen 5 is a steel frame precast concrete structure of the present invention as shown in FIG.

Inside this, eight H-shaped copper 230 and its surrounding rebar 250 are provided, and the center is hollow.

Each of the specimens 4 and 5 was a cylindrical column having a diameter (D) of 0.9 m, an inner diameter (I) of 0.3 m, and a height (T) of 2.6 m. These were mounted on a 0.75 meter high base 200 as shown in FIG.

(Test method)

An axial force loading jack 300 was installed on the upper surface of the test piece, a PC steel rod 310 was hung from this jack 300, and the lower end was embedded and fixed in the base 200. Connected to the NC 320. Also, an actuator 350 was installed between the stub 330 at the upper end and the reaction wall 340, and one end thereof was fixed to the stub 330.

In such a situation, the PC steel rod 3 10 is pulled by the axial load jack 3 0 0 As a result, the actuator 350 was actuated while applying a predetermined axial force to the entire test piece, and a positive and negative horizontal force was repeatedly applied to the stub 330.

(Test results)

FIG. 40 shows the horizontal displacement of the loading point of the specimen 4 and FIG. 41 shows that of the specimen 5 which is the structure of the present invention. The vertical line shows the load (t f), the horizontal line shows the horizontal displacement at the load point in millimeters, and the dotted line shows the calculated ultimate strength.

Fig. 42 shows the relationship between the load and the displacement (envelope) of the test specimens 4 and 5, the vertical axis represents the load (tf), and the horizontal axis represents the horizontal displacement at the load point.

In the above results, Specimen 4 and Specimen 5 show almost the same deformation performance, and Specimen 5 shows toughness exceeding Specimen 4.

As described 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. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is used in the construction of a concrete structure, and is particularly useful for the construction of a concrete structure such as a pier which requires work at height.

Claims

The scope of the claims

1. A step of forming a foundation by embedding a steel frame to a required height, a step of forming a frame-shaped form member in which a reinforcing bar is arranged via a reinforcing bar fitting inside, and a mold surrounding the steel frame. Stacking a plurality of frame members, casting concrete into a precast form formed by the stacked form members and hardening, and integrating the steel frame, the band reinforcing bar and the precast form, For building concrete structures with

2. The method for constructing a concrete structure according to claim 1, wherein a reinforcing bar assembly is disposed on an inner surface of the form member, and a reinforcing bar is fixed to the reinforcing bar assembly.

3. Inside the form member, a reinforcing bar and a steel material are arranged so as to be alternately stacked with a space therebetween, and the reinforcing bar is fixed to a reinforcing bar assembly material arranged on one side of the form member, and the steel material is a formwork. 2. The method according to claim 1, wherein the concrete structure is fixed in a transverse direction of the member.

4. The method for building a concrete structure according to claim 1, wherein the reinforcing bars are a band reinforcing bar and an intermediate reinforcing bar.

5. The method for constructing a concrete structure according to claim 1, wherein a steel frame having a projection formed on a surface in contact with the concrete is used.

6. The steel concrete structure is hollow, and the precast formwork is composed of a precast outer frame member arranged outside the steel frame, and a precast inner frame member arranged inside the steel frame, 2. The method for constructing a concrete structure according to claim 1, wherein the rebar frame and the rebar are attached to one or both of the precast outer frame member and the precast inner frame member.

7. The method for constructing a concrete structure according to claim 6, wherein a reinforcing bar is attached to the form member via a reinforcing bar frame.

8. Precast formwork, steel frame provided inside the precast formwork, concrete and cast in the precast formwork, the precast formwork is made of mortar, steel fiber One or more reinforcements selected from the group consisting of, stainless steel fiber, aramide, vinylon, carbon fiber, and glass fiber Concrete structure characterized by mixing wood.

9. The concrete structure according to claim 8, wherein the steel frame is an H-shaped steel, and a projection is formed on a flange surface thereof.

10. Attach a reinforcing bar on the inner surface, attach a reinforcing bar to the reinforcing bar, form a frame, and use steel fiber, stainless fiber, aramid, vinylon, carbon fiber and glass as reinforcement Formwork material containing one or more fibers.

11. The mold member according to claim 10, wherein the base mortar is a cement-based mortar having a water-cement ratio of 20 to 60%.