JPH0272905A - Manufacture of prestressed concrete member and latticelike reinforcing rod for prestressed concrete member - Google Patents

Abstract

PURPOSE:To improve an anchor effect of prestressed concrete and contrive a reduction in a manufacturing cost dy eliminating the wastefulness of a material, by a method wherein an anchor reinforcing part for introduction of the prestressed concrete is provided unitarily on a crossing part of both ends of a latticelike reinforcing rods and the anchor reinforcing part is laid within a prestressed concrete member. CONSTITUTION:A latticelike reinforcing rod 2 is manufactured by constituting the title method so that a continuous fiber impregnated with resin is hung away in order in a longitudinal and lateral directions on pins positioning at both ends of an axial reinforcing rod 5a and force distributing reinforcing rod 2b and fiber groups of at least three layers are superposed alternately upon each other at a crossing part without fail. An anchor reinforcing part 21 made of fiber-reinforced plastic where the crossing part 6' is laid is molded unitarily at the each crossing part 6' between each axial reinforcing rod 2a and the each force distributing reinforcing rod 2b, in both end parts of the axial reinforcing rod 2, where prestressed concrete is introduced, out of the latticelike reinforcing rods 2. An anchor effect of prestressed concrete is improved and a reduction in a manufacturing cost can be contrived by eliminating the wastefulness of a concrete 1 as it is laid.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for manufacturing prestressed concrete members and a lattice reinforcement for prestressed concrete members.

"Conventional technology and its problems" Prestressed concrete members are made by applying compressive stress to concrete using tendons (for example, PCJLI wire, etc.), which compensates for the lack of tensile strength of concrete and resists tension within the design load range. It also has various advantages, such as ensuring the same mechanical properties under compression and creating a structure that does not cause cracks.

However, on the other hand, high quality is required of PCJLI wire and concrete because it applies a large compressive force to concrete over a sustained period of time, but in recent years, steel wires in concrete have been subject to deterioration due to salt corrosion, electrical corrosion, or freezing damage. This is becoming a problem. Therefore, we have traditionally changed the tension material for PC from conventional PC steel wire to fiber-reinforced plastic (FRP).
) is being researched (for example, Japanese Utility Model Publication No. 51-53071).

Conventionally, rod-shaped products manufactured by the pultrusion method, which involves applying a certain tension to FRP tensile material tension fibers while converging, forming, and reinforcing them to produce FRP rods, have been used, and are mainly used for making bosts. It is used as a tension method. After the concrete has hardened, the tension material is inserted into a duct that has been prepared in advance, and is fixed by applying a tensile force, thereby introducing prestress into the concrete.

However, in order to apply tensile force to the FRP tension material and fix it, a special jig (crimping friction type grip, etc.) is required, and the introduction of prestress is mostly limited to the boss tension method. This is the actual situation, and for this reason, it is difficult to achieve mass production in factories.

The present invention has been made in view of the above circumstances, and includes a method for manufacturing a prestressed concrete member, which uses lattice reinforcing bars as a tension material and introduces prestress into concrete by a pretension method, and a lattice reinforcement for prestressed concrete members. The purpose is to provide a plot.

"Means for Solving the Problem" In order to solve the above problem, the method for manufacturing a prestressed concrete member according to the present invention is characterized by comprising steps (a) to (e) as shown below. That is.

(b) A step of integrally constructing a lattice-shaped reinforcing bar mainly made of a reinforced plastic material and containing continuous fibers at least in the axial direction; (b) A step of applying tension to the lattice-shaped reinforcing bars at the intersections of both ends of the lattice-shaped reinforcing bars, respectively. (c) arranging the lattice-like reinforcing bars in the formwork of the prestressed concrete member to be formed; (d) the fixing reinforcement part for applying force; a step of attaching a fixing device to the fixing device, applying a jacking reaction force through the fixing device, and applying a tensile force to the shaft portion by the jacking;
(E) A step of pouring concrete into the formwork.

The fixing device includes a connecting tool that extends from outside the formwork into the formwork and can be engaged with the fixing reinforcing section, and a proximal end of the connecting tool and an end of the jack that are detachably connected to each other. It is desirable to have a connecting portion.

Further, the lattice reinforcement for prestressed concrete members according to the present invention is a prestressed reinforcement in which lattice reinforcement mainly made of reinforced plastic material is embedded in concrete and tensile force is applied in the axial direction of the lattice reinforcement. A lattice-shaped reinforcing bar for a concrete member, wherein the lattice-shaped reinforcing portion includes continuous fibers at least in its axial direction, and tension is applied to the lattice-shaped reinforcing bar at intersections at both ends of the lattice-shaped reinforcing bar. A fixing reinforcement part made of reinforced plastic material is provided to provide force.

It is preferable that the lattice-shaped reinforcing portion is integrally formed by laminating three or more layers of resin-impregnated continuous fibers that intersect with each other.

"Function" According to the present invention, the reinforced plastic anchorage reinforcing sections provided at the intersections of both ends of the lattice reinforcing bars used as tension members in the axial direction are used as anchoring sections for introducing prestress, and are inserted into the concrete. Since it is buried in the lattice reinforcement, there is no loss of lattice reinforcement.

In addition, because the elastic modulus of the square grid reinforcement is smaller than that of PCM material, even if concrete undergoes elastic deformation, creep, or drying shrinkage, the tensile force applied to the tendon material is less likely to decrease, and the concrete Prestress loss is reduced.

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

FIGS. 1 and 2 show an example of a one-way breast-stressed concrete plate manufactured by the method of manufacturing a pre-stressed concrete member of the present invention and suitably used, for example, as a slab of a pedestrian bridge.

As shown in the drawing, this prestressed concrete member (version) A is composed of concrete I that forms the main body of this member A.
and lattice-shaped reinforcing bars 2 buried inside this concrete 1, and each shaft part 2a, 2 extends in the longitudinal direction of the concrete 1 of the lattice-shaped reinforcing bars 2.
The basic structure is that prestress is introduced into concrete l by applying tensile force to a.

For example, the entire concrete 1 has a diameter of 2θθcmX5
It is formed into a square rectangular plate shape with a size of approximately θCff1 It has a cross-sectional structure that is buried slightly below the center.

To specifically explain the lattice-shaped reinforcing bars 2, this Nli reinforcing bar 2 has a plurality of continuous fibers 3 (the continuous fibers 3 themselves The fiber bundle 4 is made of a fiber bundle 4 (which is actually composed of a plurality of continuous m vertebrae) and is fixed and molded with resin in a lattice shape. That is, as shown in FIGS. 3 to 5, the reinforcing bars 2 are made up of fiber bundles 4 made up of a plurality of aligned continuous fibers 3 (see FIG. 4) that intersect with each other to form a lattice shape. , six fibers 'a3 of these fiber bundles 4 are bound together with a resin material 5.

Note that, as shown in FIG. 5, the intersection 6 between the fiber bundles 4 has three or more layers (a fiber group 3a extending in one direction and a fiber group 3b extending in the other direction perpendicular to the fiber group 3a). In the illustrated example, the cross-sectional shape is formed by laminating 16 layers.

The continuous fibers 3 that are the main components of the lattice reinforcing bars 2 may be glass fibers, carphone fibers, or carbon fibers that are lightweight and have high strength.
Aramid fibers and the like are mainly used, and other fibers, such as synthetic resin fibers, ceramic fibers, metal fibers, etc., are used in appropriate combinations as necessary. In addition, as the resin material 5, for example, vinyl ester resin, which has good adhesion to the continuous fibers 3 and has sufficient strength properties itself, is mainly used, and in addition, unsaturated polyester resin, evoquino resin, phenol resin, etc. Resin etc. are used. The ratio of these continuous fibers 3 and resin material 5 is as follows:
For example, if the continuous fiber 3 is glass fiber and the resin material 5 is vinyl ester resin, the volume ratio of the continuous fiber 3 is 30 to 7.
It is set to be approximately 0%.

Five shafts 2 are provided at both ends of such a lattice reinforcing bar 2.
At each intersection 6° (10 locations in total) of horizontal reinforcements (distribution reinforcement) 2b, 2b7 at both ends of a..., fixed reinforcing portions 21 for introducing prestress, which will be described later, are molded at each intersection. It is provided integrally so that 6° is buried. This fixing reinforcing section 21 is made of fiber reinforced plastic.

This prestressed concrete member A having the above-mentioned structure is made by fixing high-performance continuous fibers 3 such as glass fibers, carphone fibers, aramid fibers, etc. with a resin material 5, and using reinforcing bars 2 formed in a lattice shape as a tension material. Since tensile force is applied to the shaft portion 2a of the lattice reinforcement 2 and prestress is introduced into the concrete l, corrosion does not occur within the concrete member, resulting in a product with excellent corrosion resistance and durability. can do. In particular, by introducing prestress into the concrete, the load that causes cracks in the concrete increases, so that the concrete can be used effectively, and the thickness and width of the member can be reduced to reduce the cross-sectional area. Moreover, the lattice-shaped reinforcing bars 2 having the above structure
has a smaller elastic modulus than conventional PC steel, so even if concrete undergoes elastic deformation, creep, or drying shrinkage, the tensile force applied to the tendons will decrease less, and the loss of prestress in the concrete will be smaller. There are advantages such as

Next, an embodiment of a method for manufacturing the prestressed concrete member A having the above structure will be described in order of steps.

(1) Forming of lattice-shaped reinforcing bars The method of manufacturing the lattice-shaped reinforcing bars 2 having the above structure is arbitrary, but for example, a method for manufacturing lattice-shaped reinforcing bars 2 having bins around them corresponding to the constituent parts and longitudinal components of the lattice-shaped reinforcing bars 2, respectively, can be used. Using a disk (not shown), the resin-impregnated continuous fibers 3 are sequentially hooked vertically and horizontally onto pins located at both ends of the shaft portion 2a and the distribution bar 2b in a so-called one-stroke manner. Then, the lattice-shaped reinforcing bars 2 are manufactured so that the fiber groups alternately form three or more layers at the intersections.

The continuous fibers can of course be fed manually, but a method is adopted in which the continuous fibers are automatically fed by mechanical means that operate based on a program in which the passing order is set in advance.

After completing the continuous fiber supply process in this way, use a pressing plate to press the entire surface from the top side on the surface plate to make the thickness uniform, resulting in a rectangular lattice shape as shown in Figure 3. A reinforcing bar 2 is obtained.

In the illustrated example, the planar orthogonal lattice-shaped reinforcing bars 2 are described, but the present invention is not limited to this in any way, and depending on the required arrangement of the reinforcing bars, It goes without saying that the shape and cross-direction of the lattice are arbitrary, such as a part of the lattice with large squares, or a three-dimensional one in which the entire lattice is in the form of a brush.

(ii) Forming of the fixing reinforcing portion As shown in FIGS. 6 to 8, the lattice reinforcing bars 2
Among them, at both ends of the shaft portion 2a... where prestress is introduced, fibers are embedded in the intersection portions 6′ (10 locations in total) between each shaft portion 2a and the distribution reinforcement 2b. The fixing reinforcing portions 2I made of reinforced plastic are integrally molded. In the illustrated example, the fixing reinforcing portion 2I is formed into a rectangular parallelepiped shape extending in the longitudinal direction of the shaft portion 2a with the intersection 6° as the center, and is provided on both sides of the fixing member 21 as shown in FIG. Elliptical locking step portions 22, 22 extending in the direction of the distribution bar 2b are protrudingly provided on the upper locking step portion 2.
2.22 is provided with protrusions 22a on both side surfaces thereof, which protrude in the longitudinal direction toward the center of the shaft portion 2a.

(iii) Introduction of prestressing Once the anchoring members 21 have been formed at each intersection 6°, as shown in FIG. A plurality of reinforcing bars 2 (three in the illustrated example) are arranged, and then a lattice-shaped reinforcing bar 2 is arranged within the plurality of formworks 30. At this time, the fixing reinforcing portions 21° 21 at both ends are fixed to the tip of the jack 35 via the fixing device 42, respectively. A telescopic rod 35a provided at the rear end of the jack 35 is fixed to a fixed block 40.

In addition, the arrangement interval of the plurality of formworks 30 is
It is sufficient if the spacing is narrow enough to allow a cutting jig such as a cutter to be inserted between the two, and from the viewpoint of minimizing waste of material, it is preferable to arrange the two as close as possible.

Here, the configuration of the fixing device 42 will be explained.
2, as shown in FIG. 1θ and FIG.
a shaft portion 44 attached to the tip of the jack 35;
It is composed of a connecting plate 45 that is located outside the formwork 30 and connects the connecting tool 43 and the shaft portion 44 to each other, and the shaft portion 44 and the connecting plate 45 constitute the connecting portion 46.

The connecting tool 43 is a metal plate having a bent portion 43a that engages with the locking step portion 22 of the fixing member 21, and a longitudinal direction of the force distribution bar 2b from the upper and lower ends of the bent portion 43a. It consists of upper and lower arm parts 43b and 43b that extend parallel to the direction of the jack 35 through the slit 31 of the formwork 30 along the
A through hole 47 passing through the arm portions 43b and 43b vertically is formed at the tip end of the arm portions 43b, 43b, respectively.

The bent portion 43a that engages with the locking step portion 22 is prevented from coming off by locking protrusions 22a provided on both sides thereof.

The shaft portion 44 is a metal prism, and its front end 1
4a has a notch 48 penetrating through both side surfaces, and through holes 49a and 49b penetrating from the notch 48 to the top and bottom surfaces, respectively.
A through-hole 50 is formed horizontally on both sides of the housing. With the rear end 44b of the shaft portion 44 inserted into a vertically penetrating notch 35b formed at the tip of the jack 35, the shaft portion 44 can be jacked via a bolt 51 inserted horizontally into the notch 35b. It is connected to the tip of 35.

The connecting plate 45 is a triangular metal plate, and a pair of through holes 52 and 52 that penetrate vertically and have the same diameter as the through hole 47 of the connector 43 are bored in the front end 45a of the connecting plate 45. Further, a through hole 53 is formed in the rear end 45b of the connecting plate 45, passing through it vertically and having the same diameter as the through holes 49a, 49b of the shaft portion 44.

In each of the connectors 43, the shaft portion 44, and the connecting plate 45, the pair of hook portions 43 and the connecting plate 45 are connected by inserting the two pins 54, 54 into the pair of through holes 47, 52, 47, respectively. The shaft portion 44 and the connecting plate 45 are connected to each other by inserting one bolt 54 into the through holes 49a and 5349b.

After arranging the lattice-shaped reinforcing bars 2 in the formwork 30 and fixing the fixing device 42 to the strong part 21 of the fixing member 1i in this way, the rod 35a of the jack 35 is retracted, and the shaft of the lattice-shaped reinforcing bars 2 is Apply the required tensile force to 2a. Then,
Concrete is poured into each formwork 30, and when the concrete reaches the required compressive strength, the jacks 35 are loosened, and then the shafts 2a between the formworks 30 and the connectors 43 located outside the formworks 30 are The arm portions 43b of are cut.

Then, by removing each formwork 30 and finishing both end faces, a prestressed concrete member A as shown in FIGS. 1 and 2 is obtained.

Note that the bent portion 43a of the connector 43 is buried in the concrete, but the arm portion 43 located outside the formwork 30
Regarding b, (1) cut it as described above, (2) bend it, and (3) if it is to be used as a joint part, take steps such as extending it from both ends to the left and right. Which method to choose?
It is determined as appropriate depending on the end shape of the prestressed concrete member A, usage pattern, etc.

In the prestressed concrete member A produced in this way, the crossing portions 6 of the lattice reinforcing bars 2 are
Since an FRP fixing reinforcing part 21 is integrally provided to introduce prestress into the shaft part 2a, by burying this fixing reinforcing part 21 in the conokuri-1-1,
In addition to enhancing the fixing effect of prestress, it is possible to reduce waste of materials and reduce manufacturing costs. In addition to this, (1) the lattice intersections 6 of the lattice reinforcing bars 2 can be used as anchoring parts for the tension material, and (2) the tension cannot be maintained over the entire length as in the case of PC steel wire. (3) There is no need for a special fixing jig such as the boss tension method.

Furthermore, in the method of manufacturing the prestressed concrete member A of this embodiment, (1) the integrity of the anchorage reinforcing portion 21 and the lattice reinforcing bars 2 can be ensured, which is very advantageous structurally; (2) Lattice reinforcing bar 2 and anchoring reinforcing section 2
If 1 and 2 are manufactured in the same process, mass production is possible.
(3) Since each component of the fixing device 42 is connected by pins or bolts, the fixing reinforcement part 2 of the jack 35 and the lattice reinforcing bar 2 can be
(4) The fixing device 42 should be easy to attach to the fixing device 1 and also be easy to remove after introducing prestress.
Regarding the connector 43, the bent part 43a is buried in concrete, and the arm part 43b outside the formwork 30 can be easily finished by cutting, bending, etc., which simplifies the work. It is possible to speed up the process. Moreover, waste of materials can be kept to a minimum.

Further, in the above-mentioned embodiment, an example was explained in which the method of the present invention was applied to a slab used for a pedestrian bridge, but the manufacturing method of the present invention can also be suitably used for lath construction of prestressed concrete members for a pond. In particular, if the lattice reinforcing bars 2 are three-dimensionally formed into a brush-like shape and prestress is introduced therein, it becomes possible to introduce prestress into the entire beam or column member.

Furthermore, in the above-described embodiment, the mutually orthogonal shaft portions 2a and distribution bars 2b of the lattice-shaped reinforcing bars 2 each contain continuous fibers. In some cases, the material is reinforced plastic and continuous fibers are included only in the shaft portion where prestress is introduced. In this case, by reducing the amount of continuous fiber used, the desired objective can be achieved while reducing manufacturing costs.

Furthermore, the desired purpose of the lattice-shaped reinforcing bars can also be achieved by using, as the lattice-shaped reinforcing bars, two iron plates formed into a lattice shape by pressing or the like.

FIG. 12 shows a second embodiment of the present invention, in which the structure of the reinforcing portion 21 fixed to the prestressed concrete member shown in the first embodiment is changed.

As shown in FIG. 12, at both ends of the lattice reinforcing bars 2,
A fixing reinforcing portion 6° for reinforcing each intersection 6° of the shaft portion 2a... and the distribution bars 2b, 2b at both ends is connected to the distribution bars 2b, 2b and each intersection 6'. They are integrally provided by molding in the form of embedding them respectively. The front surface of the fixing reinforcing section 60 (the center side of the lattice reinforcing bars 2) is formed with a U-shaped curved surface so that it can be easily engaged with the connector 43 of the fixing device 42. And each intersection 6°
By engaging the pair of connectors 43° 43 of the fixing device 42 with the fixing reinforcing portions 60 on both sides of the shaft portion 2a,
It is designed to apply a tensile force to...

According to this embodiment, the fixing reinforcing portion 6o is connected to the distribution bar 2b at both ends.
Since the fixing reinforcing portion 60 is constructed integrally with the fixing reinforcing portion 60 in a buried form, the structure of the fixing reinforcing portion 60 becomes stronger, which is structurally advantageous in applying tensile force to the shaft portion 2a by the connecting tool 43. Further, in the manufacturing process of the lattice-shaped reinforcing bars 2, the fixing reinforcing portions 6o can be manufactured integrally with the both-end distribution bars 2b by molding, so that the number of manufacturing steps can be reduced. Furthermore, the fixing reinforcing section 60 can be used as a fixing section for concrete, and it is also possible to reduce manufacturing costs by eliminating wasted materials.

"Effects of the Invention" As explained in detail above, in the method for manufacturing a prestressed concrete member according to the present invention, fixed reinforcing sections for introducing prestress are integrally provided at the intersections at both ends of the lattice reinforcing bars. Therefore, by embedding this anchorage reinforcement part within the prestressed concrete member,
It is possible to further enhance the fixing effect of prestress, and to reduce the manufacturing cost by eliminating waste of materials.

In addition, since tensile force is applied to the lattice-shaped reinforcing bars by the jack via the fixing device that engages with the fixing reinforcement parts provided at both ends of the lattice-shaped reinforcing bars, the fixing work between the jack and the fixing reinforcement parts and The removal work of both is easy,
This can simplify the work of introducing prestress and contribute to improving workability in the manufacturing process.

Moreover, because the strength of the intersections of the lattice reinforcing bars is high, all intersections can be used as anchorage points for tendons, and even if the concrete cracks in some areas or loses its adhesion, , the decrease in tensile force is small, and there is no fear that the tension cannot be maintained throughout the wire as in the case of PC steel wire.

Furthermore, since pre-stress is introduced using the pre-tension method, there is no need for special fixing jigs like those used in the post-tension/con method.
This has excellent effects such as eliminating complicated on-site work such as fixing work for both ends of the member, and improving work efficiency on-site.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view of a prestressed concrete member, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a perspective view showing a part of lattice reinforcement, and FIG.
The figure is a sectional view of a straight portion of a fiber bundle, FIG. 5 is a sectional view of an intersection between a fiber bundle and a fiber bundle, and FIGS. 6 to 11 are shown to explain an embodiment of the manufacturing method of the present invention. The 6th
The figure is a plan view showing a reinforcing bar provided with a constant n reinforcement part.
The figure is a front view of the same, Figure 8 is an enlarged perspective view of the main part of the fixing reinforcing section, Figure 9 is a plan view showing the reinforcing bars arranged in the formwork, and Figure 10 is the fixing reinforcement part. FIG. 12 is a plan view of the apparatus, FIG. 1... Concrete, 2... Grid h
li strong reinforcement, 2a... shaft portion, 2b... distribution reinforcement, 3... continuous fiber, 5... resin,
6...Cross section, 21.60...Fixing reinforcement section, 30...
Formwork, 35...Glossy, 42...Fixing device, 13...Hook part, 16...
・・Abebe, A・・Prestressed concrete member. Applicant t? l Suiwa Risetsu Co., Ltd. Inu l Honsho Industrial Company 50 (jD)

Claims (4)

[Claims] (1) A process of integrally configuring a lattice-shaped reinforcing bar mainly made of reinforced plastic material and containing continuous fibers at least in the axial direction, and applying tensile force to the lattice-shaped reinforcing bar at the intersections at both ends of the lattice-shaped reinforcing bar, respectively. a step of reinforcing and molding an anchorage reinforcing section with a reinforced plastic material to give the anchorage reinforcing section, a step of arranging the lattice-like reinforcing bars in a formwork of a prestressed concrete member to be formed, and attaching an anchoring device to the anchorage reinforcing section. applying a reaction force of the jack via the fixing device;
A method for manufacturing a prestressed concrete member, comprising the steps of applying tensile force to the shaft portion using the jack, and pouring concrete into the formwork. (2) The fixing device includes a connecting tool that extends from outside the formwork into the formwork and can be engaged with the fixing reinforcing section, and a proximal end of the connecting tool and an end of the jack that are detachably connected to each other. 2. The method for manufacturing a prestressed concrete member according to claim 1, further comprising: a connecting portion that is connected to a prestressed concrete member. (3) A lattice-shaped reinforcing bar for a prestressed concrete member, in which a lattice-shaped reinforcing bar mainly made of a reinforced plastic material is embedded in concrete and a tensile force is applied in the axial direction of the lattice-shaped reinforcing bar, The lattice reinforcing bars include continuous fibers at least in the axial direction,
A lattice-like structure for a prestressed concrete member, characterized in that fixing reinforcing parts molded from a reinforced plastic material are provided at both end crossing parts of the lattice-like reinforcing bars to apply tensile force to the lattice-like reinforcing bars. Reinforcement bars. (4) The prestressed concrete member according to claim 3, wherein the lattice-shaped reinforcing bars are integrally formed by resin-impregnated continuous fibers that intersect with each other and are laminated in three or more layers.