JP2673225B2 - Prestressed concrete member and its manufacturing method and apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to a prestressed concrete member in which FRP (fiber reinforced plastic) is used as a cage-shaped reinforcing bar, and a manufacturing method and apparatus thereof.

"Conventional technology and its problems" Prestressed concrete members are those in which compressive stress is applied to concrete by a tension material (such as PC steel), which compensates for the lack of tensile strength of concrete and Also, it has various advantages such as securing the same mechanical properties against compression and forming a structure free from cracks.

However, on the other hand, high quality is required for steel materials and concrete because it continuously gives a large compressive force, but in recent years deterioration of steel materials in concrete due to salt corrosion and electrical corrosion has become a problem. . Therefore, a technique for replacing a conventional PC steel material with a conventional PC steel material by a fiber reinforced plastic (FRP) has been studied (for example, Japanese Utility Model Publication No. 51-53071).

Conventionally, this kind of FRP tension material, which is manufactured by the pull-through method of manufacturing FRP rod by focusing, molding and strengthening while applying a constant tension to the fiber, is mainly applied as a post tension method. It is used. These are inserted the tension material in the duct provided in advance after hardening of the concrete, apply a tensile force to fix it,
It is to introduce prestress into concrete. However, in order to apply tensile force to the FRP tension material and fix it, a special jig (compression friction type grip etc.) is required,
Most of the introduction of pre-stress is limited to the post-tension system, which makes it difficult to mass-produce it in factories.

The present invention has been made in view of the above circumstances, and provides a prestressed concrete member that uses fiber-reinforced plastic reinforcing bars as a tension member and introduces prestress into concrete by a pretensioning method, and a manufacturing method and apparatus thereof. Is intended.

"Means for Solving the Problem" In order to solve the above problems, a prestressed concrete member according to the present invention comprises concrete, and a basket-like reinforcing bar embedded in the concrete and having an axial bar and a shear reinforcing bar. , And a prestressed concrete member that applies tension to the axial reinforcement, wherein the cage reinforcement is formed integrally by crossing resin-impregnated continuous fibers in one direction and in a direction orthogonal thereto. It is a thing. At the intersection of the axial reinforcement and the shear reinforcement, it is desirable that the continuous fibers constituting these be alternately laminated in three or more layers.

The method for producing a prestressed concrete member according to the present invention is characterized by including the following steps (a) to (e).

(A) A process of cross-linking resin-impregnated continuous fibers in one direction and in a direction orthogonal to this to integrally form a cage-shaped reinforcing bar composed of axial reinforcement and shear reinforcing reinforcement, (b) introducing prestress A step of molding fixing blocks made of fiber reinforced plastic at both ends of the cage-like reinforcing bar to be formed, (c) a step of placing the cage-like reinforcing bar in a form of a prestressed concrete member to be formed, (D) A step of removing the reaction force of the jack with the fixing block and applying different tensions to the upper and lower axial lines by the jack, (e) Placing concrete in the formwork, and this casting concrete is required. After reaching the strength of 1., the step of loosening the jack and cutting the cage-like reinforcing bar and fixing block located outside the mold.

Further, the manufacturing apparatus according to the present invention includes a mold for penetrating the cage-like reinforcing bar, a base on which the mold is placed, and at least one end of a shaft of the cage-like reinforcing bar provided on the base. A fixing block for fixing the fixing member and at least three jacks provided in a three-dimensional shape on the base to apply a tension force to at least the other end of the axial reinforcement of the cage reinforcement.

[Operation] According to the present invention, the basket-like reinforcing bar composed of the axial reinforcing member and the shear reinforcing bar used as the tension member is formed into a cage by solidifying continuous fibers with resin, and the crossing of the axial reinforcing bar and the shear reinforcing bar is performed. Since the strength of the portion is high, the intersecting portion can be used as the fixing portion, and a special fixing jig is unnecessary.

Further, since the cage-like reinforcing bar has a smaller elastic modulus than PC steel material, elastic deformation of concrete, even if creep or dry shrinkage occurs, the decrease in tensile force applied to the tension material is small, and Prestress loss is reduced.

Furthermore, since the fixing block takes the reaction force of the jack and gives different tensions to the upper and lower axial muscles by this jack, it is more effective by giving different tensile forces to the upper and lower axial muscles. Prestress can be introduced.

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

1 to 10 show a first embodiment of the present invention, and FIGS. 1 to 3 show a unidirectional prestressed concrete slab manufactured by the method for manufacturing a prestressed concrete member according to the present invention. Shows an example.

As shown in FIGS. 1 to 3, this prestressed concrete member (plate) A is composed of concrete 1 which is the main body of this member A, and cage-shaped reinforcing bars 2 which are embedded inside this concrete 1. And a basic structure in which a prestress is introduced into the concrete 1 by applying different tensile forces to the respective axial reinforcements 3, 3 ... Which extend in the longitudinal direction of the concrete 1 among the concrete reinforcements 2. Has become.

The concrete 1 is, for example, 1000 cm × 30 cm
It is formed into a cubic shape having a size of about 50 cm, and the cage-like reinforcing bar 2 that pre-stresses the concrete 1 is made of concrete 1 as shown in FIG.
It has a cross-sectional structure that is buried almost at the center in the plate thickness direction.

The cage-shaped reinforcing bar 2 will be described in detail. As shown in FIG. 4, the reinforcing bar 2 is a plurality of bars (six in the illustrated example) arranged in parallel vertically with a predetermined interval.
, And a plurality of (10 in the illustrated example) anchor muscles 4, 4 arranged in parallel on the left and right with a predetermined distance from each other.
, And a plurality of shear reinforcing bars 5, 5 arranged so as to intersect each of the axial reinforcement 3 and the anchor reinforcement 4 at a substantially right angle via the intersection C ₁ ,. The shear reinforcing bars 5 are arranged at predetermined intervals in the axial direction of the shaft bars 3.

And, these axial reinforcement 3, anchor reinforcement 4, shear reinforcement reinforcement 5
As shown in FIGS. 5 and 6, respectively, is made of a fiber bundle T made up of a plurality of continuous fibers 11 bundled with a resin material 10, and is solidified and molded. . Further specifically, the fiber bundle T composed of a plurality of aligned continuous fibers 11 is three-dimensionally arranged to form the axial reinforcement 3 and the anchor reinforcement 4, and the axial reinforcement 3 and the anchor are formed. By intersecting another fiber bundle T with the fiber bundle T forming the muscle 4, a shear reinforcing muscle 5 intersecting with the axial muscle 3 and the anchor muscle 4 is formed at the intersection C ₁ , and these fiber bundles T The continuous fibers 11 are bound and integrated by the resin material 10.

The intersecting portion of the fiber bundles T (that is, the intersecting portion C ₁ ) has a fiber group 11a extending in one direction and a fiber group 11b extending in a direction orthogonal to the fiber group 11a shown in FIG. As described above, the cross-sectional shape is formed by alternately stacking three or more layers.

As the continuous fiber 11 which is the main component of the reinforcing bar 2, glass fiber, carbon fiber, aramid fiber and the like which are lightweight and have high strength are suitable, but if necessary, other fibers such as synthetic resin fiber, ceramic fiber, You may use metal fiber etc. Also, these fibers may be used in an appropriate combination.

Further, as the resin material 10 for binding the continuous fibers 11 of the fiber bundle T, for example, vinyl ester resin or the like, which has good adhesiveness to the continuous fibers 11 and has sufficient strength itself, is preferable. Other resin materials may be used depending on the type of the fiber 11 to be used. As other resin materials, unsaturated polyester resin, epoxy resin, phenol resin and the like can be mentioned.

Regarding the ratio of the continuous fiber 11 and the resin material 10, the fiber
It is appropriately determined in consideration of the type and strength of 11, and the usage pattern of the reinforcing bar 2. For example, when the continuous fiber 11 is a glass fiber and the resin material 10 is a vinyl ester resin,
As the continuous fiber 11 is about 30 to 70% by volume, and when the continuous fiber 11 is, for example, pitch-based carbon fiber,
It is desirable to consider it to be about 20 to 60%. When the proportion of the continuous fibers 11 is less than the above, the strength of the cage reinforcing bar 2 is remarkably reduced. On the other hand, when the proportion of the continuous fibers 11 is increased, a reinforcing member having such high strength can be obtained, but it is too high. If the ratio is set, a relatively expensive one such as carbon fiber is not preferable in terms of economy.

In addition, according to the experimental results, the tensile strength of the fiber bundle T in which the glass fiber (fiber diameter 23 μm) to the vinyl ester resin has a volume ratio of 38% is 46.4 kg / mm ² , and the intersection C ₁
Was 20 kg / mm ² . When the volume ratio of carbon fibers (fiber diameter 8 μm) is 20%, the tensile strength of the fiber bundle T is 20.4 kg / mm ² .
The bending shear strength of the intersection C ₁ was 11 kg / mm ² .

The prestressed concrete member A having the above-described structure uses high-performance continuous fibers 11 such as glass fiber, carbon fiber, and aramid fiber fixed with a resin material 10 and uses a cage-shaped reinforcing bar 2 as a tension material. This cage reinforcement 2
Since a tensile force is applied to the shaft bar 3 and the prestress is introduced into the concrete 1, corrosion in the concrete member does not occur, and a product having excellent corrosion resistance and durability can be obtained. In particular, the introduction of prestress into concrete increases the crack generation load of the concrete, so that the concrete can be effectively used, and the member thickness and the member width can be reduced to reduce the cross-sectional area. In addition, since the reinforcing bar 2 having the above-mentioned structure has a smaller elastic coefficient than that of the conventional PC steel material, even if elastic deformation, creep or drying shrinkage of concrete occurs, the tensile force applied to the tension material is less reduced, and There is also an advantage that the prestress loss is small.

Next, an example of an apparatus for producing the prestressed concrete member A having the above-mentioned configuration
This will be described with reference to the drawings and FIG.

In the figure, reference numeral 20 is a formwork of the prestressed concrete member A to be formed, reference numeral 21 is a base on which the formwork 20 is placed,
Reference numeral 22 is a support member having both ends supported at the upper and lower ends of a fixing block 30 which will be described later and is formed at both ends of the cage reinforcement 2 arranged in the form 20, and 23 is the cage reinforcement 2. A fixed block for fixing one end, 24 is a group of jacks that take a reaction force by the support member 22 and give a tension force to the shaft muscle 3 of the cage reinforcement 2 through the fixing block 30. , And constitutes a main member of the manufacturing apparatus B.

The formwork 20 includes a bottom formwork 20a and side formwork 20b arranged around the bottom formwork 20a so as to surround the bottom formwork 20a.
And the subject. The side mold 20b is provided with slits (5 places) 25 through which both ends of the axial reinforcements 3, 3 ... of the cage reinforcement 2 arranged in the form 20 penetrate (drop). ing.

The base 21 on which the mold 20 is placed is entirely formed in a flat rectangular shape. The fixed blocks 23 are erected on both ends of the base 21 in the longitudinal direction (that is, in the axial direction of the cage reinforcement 2). The fixed block 23 has its base end fixed to a predetermined position on the upper surface of the base 21 with four bolts 23b ... Through a mounting plate 23a. The mounting holes 21a for the four bolts 23b on the base 21 are provided at four positions in the front and rear, respectively, and the fixing position thereof is changed in the front and back according to the size of the prestressed concrete member A to be manufactured. be able to.

The support member 22 includes a plate-shaped main body 22a located between the fixing block 30 and the fixed block 23, and bent portions 22b and 22b extending from the upper and lower ends of the main body 22a in parallel with the upper and lower surfaces of the fixing block 30, respectively. And 3 hinges 26a fixed to the inner surface of the bent portion 22b in the width direction, and 4 hinge portions fixed to the upper and lower surfaces of the fixing block 30 in the width direction. 26b ... and intermeshing with each other, by a pin 26d having nuts 26c at both ends,
They are hinged so as to be rotatable relative to each other.

The group of jacks 24 is composed of four hydraulic jacks 27, 27 ... Having a pair of rods 27a.
The one rod 27a is hooked to the hooks 27b at the four corners of the main body portion 22a of the support member 22, and the other rod 27a is hooked to the hooks 27b on the inner surface of the fixed block 23. And
By expanding and contracting the rods 27a of the four jacks 27, a tension force is applied to the axial line 3 through the support member 22 and the fixing block 30. Therefore, one of the pair of left and right jack groups is used as a fixing means for fixing the shaft reinforcement 3 of the cage reinforcement 2 to the fixing block 23 and the other as a tensioning means for applying a tension force to the shaft reinforcement 3. Or both can be used as a tension means from the left and right.

The main body portion 22a of the support plate 22 is provided with the hooking members 27b at a total of 24 positions, that is, 6 positions on the upper and lower ends and 6 positions on both sides. Similarly, the inner surface of the fixed block 23 is provided with 24 hooking members 27b ... Corresponding to the 24 hooking members 27b. Therefore, the attachment position of the jack 27 and the number of attachments can be set arbitrarily, and the optimum prestress introduction position and tension can be given. Further, a roller 28 slidable on the base 21 is attached to the lower end of the lower bent portion 22b of the support plate 22.

Next, a method of manufacturing the prestressed concrete member A using the manufacturing apparatus S configured as described above will be described in the order of steps.

(I) Molding of cage-shaped reinforcing bar The method for molding the cage-shaped reinforcing bar 2 having the structure shown in FIG. 4 is optional, but, for example, resin (normal temperature curable fluid resin etc.) is impregnated. The continuous fiber 11 is hooked in a so-called one-stroke writing manner on pins or the like provided at positions corresponding to both ends of each axial reinforcement 3 ... and Anchor reinforcement 4. The continuous fiber 11 impregnated with the resin is wound around the position.

At this time, at the intersection C between the axial reinforcement 3, the anchor reinforcement 4, and the shear reinforcement reinforcement 5, the fiber groups must be alternately laminated in at least three layers or more. Furthermore, it is necessary to apply sufficient tension to the continuous fiber 11 to maintain the linearity. In some cases, it is necessary to dispose the axial reinforcement 3 and the anchor reinforcement 4 while avoiding the bent portions at the four corners of the shear reinforcing bar 5 (because the axial reinforcement 3 is arranged at the bent portion of the shear reinforcing bar 5). If it is installed, the stress from the axial line 3 may be transmitted to the bent portion and the fracture may occur there.

Here, the continuous fibers 11 can be supplied manually, of course, but may be automatically executed by a mechanical means that operates based on a program in which the passage order is set in advance.

After the continuous fiber supply step is completed in this manner, finally, by using a pressing plate or the like to press each bar of the reinforcing bar 2 from the upper surface and the lower surface to make the thickness uniform, as shown in FIG.
Reinforcing bars 2 each having a rectangular cross section are obtained. Here, if the surface of the pressing plate is provided with irregularities in advance, the surface of the reinforcing bar 2 can be roughened due to irregularities. In this case, the adhesion of the reinforcing bar 2 to concrete can be easily improved. The fiber 11 is
Here, a twisted string, a braid, and the like are also included.

(Ii) Molding of fixing block As shown in FIGS. 7 and 8, the cage reinforcement 2
Of the axial reinforcements 3, 3 ... Into which the prestress is introduced, the fixing blocks 30, 30 made of fiber reinforced plastic are respectively molded. This fixing block 30 is a cage reinforcement 2
Upper end fixing block 30a in which the upper end axis reinforcement 3 is embedded and lower end fixing block 30b in which the lower end axis reinforcement 3 is embedded
And a side fixing block 30c in which the anchor streak 4 is embedded. Each of these fixing blocks 30a, 30b, 30c
Is fixed by eight bolts 31 for each line.

The structure of the upper fixing block 30a will be further described. As shown in FIG.
One end of the axial shaft 3 is provided with two shear reinforcements 4 in the width direction.
And a pair of mesh fibers 32, 32 arranged so as to cover and sandwich from above and below, and a resin material 33 for binding the mesh fibers 32, 32 and the axial reinforcement 3 and the shear reinforcing reinforcement 4 to each other. Is formed into a rectangular parallelepiped shape. The mesh fiber 32 is formed by weaving or stacking the same fibers as the continuous fibers 11 constituting the cage-shaped reinforcing bar 2 in a mesh shape. Through holes penetrating in the thickness direction at predetermined intervals in the width direction of the upper end fixing block 30a.
A plurality of 34, 34 ... Are drilled. The other fixing blocks 30b and 30c have the same structure.

If the shear reinforcing bar 5 is embedded in the multi-row fixing block 30, the concrete 1 and the cage reinforcing bar 2 are fixed at the intersection C ₁ of the reinforcing bar 2 as will be described later. Fixing can be firmly achieved. However, if a large number of rows of excessive shear reinforcing bars 5 are provided, the fixing block 30 becomes large and the material itself is wasted. Normally, if two rows are buried, the specified purpose can be achieved, but the pulling force applied If it is small, it may be one row. Also, the fixing block 30
The mesh fiber 32 may be omitted if the tensile force introduced into the fiber is small.

(Iii) Introduction of pre-stress Once the fixing block 30 has been formed, the fixing block 30 shown in FIGS.
A prestress is introduced using the manufacturing apparatus S as shown in the figure.

First, both fixing blocks 23, 23 are positioned and fixed on the base 21 in accordance with the length dimension of the prestressed concrete member A, and the formwork 20 of the prestressed concrete member A to be formed is fixed to the base between both fixing blocks 23. Place on table 21. The four jacks 27 may be previously hooked on the hooks 27b, 22b of the fixed block 23 and the support plate 22, respectively.

Then, the cage-shaped reinforcing bar 2 having the fixing blocks 30 at both ends is arranged in the mold 20 from above while penetrating the slits 25 of the mold 20. At this time, the fixing blocks 30 at both ends
Is located outside the formwork 20. Then, the hinge portions 26a provided on the upper and lower surfaces of the upper and lower fixing blocks 30a and 30b are respectively attached to the upper and lower hinge portions of the support plate 22 by the hinge pins 26c.
The hinges are connected to 26b so that they can rotate vertically.

In this way, when the left and right fixing blocks 30 are supported by the support plate 22, the rods 27a of the jacks 27 at the left and right upper ends are evenly contracted, and the required tension is applied to the upper three shafts 3 ... of the cage reinforcement 2. Along with applying force, the rod 27a of the jack 27 at the lower end is evenly contracted to apply a required tensile force to the lower three shaft reinforcements 3 ... of the cage reinforcement 2. These upper and lower two tensile forces set the value of the tensile force of the lower end shaft reinforcements 3 ... to be larger than the value of the tensile force of the upper end shaft reinforcements 3. Therefore, the prestress can be introduced into the concrete 1 more effectively by applying different tensile forces to the top and bottom.

Bending stress is generated around the rotation axis (pin) 26c of the hinge portion 26b by these tensile forces, but this bending stress is canceled by the rotation of the hinge portion 26a of the support plate 22.

Next, concrete 1 is placed in the formwork 20, and when this concrete 1 reaches the required compressive strength, the jack 27
... After loosening each, the axial line 3 and the fixing block 30 outside the form 20 are cut. Then, by removing the formwork 20 and further finishing the both end surfaces, a prestressed concrete member A as shown in FIGS. 1 to 3 is obtained.

In the prestressed concrete member A manufactured in this way, in addition to the effects described above, the following excellent effects are exhibited. That is, since the strength of the cage-shaped reinforcing bar 2 is high, each of the intersections C ₁ ... Can be used as a fixing portion for the tension member. As a result, in addition to the adhesive strength of the reinforcing bar 2 itself, the fixing strength of the intersecting portion C _{1 as} a fixing portion is added, and as a result, the tension force applied to the axial muscle 3 is reliably maintained.

As described above, since each crossing portion C ₁ of the cage reinforcement 2 can be used as a fixing portion, even if one portion of the axial reinforcement 3 is broken, the decrease in tension is very small, and in the case of PC steel wire As you can see, there is no need to worry about being unable to maintain tension.

Since a special fixing jig such as the post-tension system is not required, complicated work such as fixing work on both ends of the member can be eliminated during the manufacturing thereof, and the workability thereof can be improved.

Furthermore, the manufacturing method of the prestressed concrete member A of this example has the following excellent effects. That is, since the fixing block 30 for introducing the prestress is made of fiber reinforced plastic, the fixing block 30 and the cage reinforcing bar 2 are integrated as compared with the case where the fixing block 30 is made of concrete, for example. It is possible to secure the property and it is very advantageous structurally. Also, when pouring concrete,
By disposing the fixing block 30 in the formwork 20 and embedding it in concrete, cutting and finishing work can be reduced.

After the concrete is poured, the manufacturing process is simpler than the hardening process, and the unit manufacturing cost is low, which is very economical. In particular, if the cage reinforcement 2 and the fixing block are manufactured in the same process, mass production is possible, which can contribute to reduction in man-hours.

Moreover, according to the manufacturing apparatus S of this embodiment, the following excellent effects are exhibited. That is, by the four jacks 27 fixed to the four corners of the support member 22,
Through the support member 22 and the fixing block 30, the cage reinforcement 2
Since different tensions are applied to the upper and lower axial muscles 3, 3 respectively, and the number and position of the jacks 27 can be arbitrarily set, it is possible to set the prestress introduction condition in a wider range, The optimum prestress introduction conditions can be sought to further enhance the effect. Also,
The cross-sectional area of the manufactured prestressed concrete member A can be reduced, and a more economical design can be achieved.

When applying a tension force, the bending stress applied to the upper and lower hinge portions 26 can be canceled by each rotation, so that the allowable value of the tensile force applied by the jack 27 can be set high, which is a safe design. .

Not only the jack 27 in the axial direction but also different tensions to the jacks 27 in the width direction can be applied to a prestressed concrete member having an overhang in the width direction. Therefore, although the prestress is introduced in one direction, three or more jacks 27 can cope with three-dimensional bending and deformation.

11 to 15 show a second embodiment of the present invention, in which the prestressed concrete member according to the present invention is applied to an I-shaped beam material.

As shown in FIG. 11, the I-shaped beam material (prestressed concrete member) B in this embodiment has upper and lower flange portions 40, 41, a web portion 42 therebetween, and both side surfaces of the web portion 42. The stiffener portions 43 are provided at equal intervals, and the size thereof has a height dimension of about 3 m or more.

As shown in FIG. 12, in such an I-shaped beam material B, a solid I-shaped cage-shaped reinforcing bar group 44 made of FRP in which prestress is introduced into each axial bar is embedded. These FRP reinforcement groups 44 consist of pre-stressed upper and lower axial muscles 4
5, consisting of shear reinforcing bar 46, anchor bar 47, the reinforcing bar group 44, and the cage-shaped web reinforcing bar 44a extending vertically from the web portion 42 into the upper and lower flange portions 40, 41, The web reinforcing bar 44a is composed of cage-like flange reinforcing bars 44b and 44c which are arranged inside the upper and lower flange portions 40 and 41, respectively.

The reinforcing bar group 44 has a cross-sectional structure similar to that of the basket-like reinforcing bar 2 in the first embodiment, and the reinforcing bars are integrally formed. Note that reference numeral 50
Is a form of the I-shaped beam material B to be formed.

The semi-cylindrical stiffener portions 43a, 43b formed on both side surfaces of the web portion 42 have, as shown in FIGS. 14 and 15, semi-arcuate reinforcing bars composed of a main bar 51a and a shear reinforcing bar 51b, respectively. 51 are buried. As shown in FIG. 15, these reinforcing bars 51 have a tubular body 53 formed by a plurality of rings 52 forming each shear reinforcing bar 51b and a main bar 51a orthogonal to the rings 52, along a diametrical direction thereof. It was cut and produced. The reinforcing bar 51 is also an integrally molded product made of FRP.

According to the I-shaped beam member B having such a configuration, since the solid I-shaped reinforcing bar group 44 is embedded, the axial bar 45 and the anchor bar 47 are provided.
Crossing portions C ₂ between the and the shear reinforcing bar 46 can be provided at a large number of places, and the tension force applied to the upper and lower axial lines 45, 45 can be more reliably maintained. Further, other operational effects are the same as those of the prestressed concrete member A in the first embodiment.

FIG. 16 shows an application example of the second embodiment, in which the prestressed concrete member according to the present invention is applied to a beam C which supports a floor slab.

The beam C in this embodiment is a T-shaped beam that supports the lower surface of the floor slab 60, and an FRP monolithic reinforcing bar group 61 is embedded in the beam C. Axial muscle 62 arranged and prestressed, shear reinforcement muscle 63,
The reinforcing bar group 61 is made up of anchor bars 64, and the reinforcing bar group 61 is made up of cage-shaped reinforcing bars 61a and 61b arranged in a T shape.

According to the beam C having such a configuration, by introducing prestress, it is possible to reduce the overall weight of the bridge, and it is possible to design an economical bridge. Since it is not exposed to the outside, it is suitable as a bridge structure that is susceptible to external factors. Other functions and effects are the same as those of the second embodiment, and therefore their explanations are omitted.

FIG. 17 shows another application example of the second embodiment, in which the prestressed concrete member manufactured according to the present invention is applied to a foot stand for constructing a girder 70 of a structure such as a road or artificial ground. It is a thing.

The pedestal D has an I-shaped cross section, and inside the pedestal D, a solid I in which primary prestress is introduced into the upper and lower axial muscles.
Model-shaped cage-shaped reinforcing bars (not shown) are buried.

Such a foot stand D is a seabed (ground) at predetermined intervals.
It is mounted and fixed on a foundation pile 72 that is installed and fixed at 71, and the girder 70 is bridged over the upper end of a foot stand D protruding to the sea. Then, inside the girder 70, the PC steel wire 73 having the span center as the lowermost end and the span ends as the uppermost end,
It is arranged with a sheath tube. Further, the fixing portions 70a of the PC steel wire 73 are provided at both ends (both ends of the span) of the girder 70, whereby the post tension type secondary prestress is introduced into the girder 70. The PC steel wire 72
In consideration of salt damage, a carbon fiber material which is a non-corrosive material may be used.

FIG. 18 shows a third embodiment of the present invention, in which the prestressed concrete member according to the present invention is applied to a wing type bridge girder having an elevated road formed on the upper surface thereof.

In this bridge girder E, the width dimension of the upper flange portion 80 is set larger than the width dimension of the lower flange portion 81. Prestress is introduced in the length direction of the bridge girder E, and A bidirectional prestressed concrete member in which prestress is introduced in the width direction.

A three-dimensional reinforcing bar group 82 is embedded inside such a bridge girder E. The reinforcing bar group 82 includes an axial bar 83 and a shear reinforcing bar.
The reinforcing bar group 82 includes a cage-shaped upper flange reinforcing bar 82a, a lower flange reinforcing bar 82b, and a web reinforcing bar 82c. Then, a tensile force is applied to the axial bars 83 arranged at the upper and lower ends of the bridge girder E to introduce prestress in the longitudinal direction of the bridge girder E, and the tensile force is applied to the shear reinforcing bar 84 arranged on the upper flange portion 80. Is given and a prestress is introduced in the width direction of the upper flange portion 80 to form a basic structure.

The method of applying a tensile force to the shear reinforcing bar 84 of the upper flange portion 80 is the same as the method of applying a tensile force to the axial bar 83 (see the first embodiment), and the anchoring blocks ( (Not shown) is molded, and the reaction force of the jack is taken by this fixing block, so that a tensile force is applied to the shear reinforcing bar 84 through the fixing block. It should be noted that these two directions of prestress introduction work are performed simultaneously.

In this embodiment, two rows of bridge girders E are respectively bridged over two rows of column pedestals 86 to form the traveling lanes of the elevated road on the upper surface, and at the same time, two rows of column pedestals are similarly provided. An oncoming lane is formed on the upper surface by spanning two rows of bridge girders E on 86. Then, a green belt is arranged on the upper surface of the plate member 87 arranged between the bridge girders E to form a central separator. A secondary prestress is introduced in the axial direction of the bridge girder E by a sheath 88 and a PC steel wire (not shown).

According to the bridge girder E of this embodiment, in the upper flange portion 80, the strength of the crossing portion of the upper flange reinforcing bar 83a is high, and each crossing portion C
₃ ... can be used as a fixing part for the tension material. Thus, joined by fixing strength as the fixing portion of the further cross section C ₃ in addition to the bond strength of the reinforcement 83a itself, as a result, tension given to the shear reinforcement 84 is reliably maintained .

In addition, in this way, each intersection C ₃ of the upper flange reinforcing bar 83a is
Since it can be used as a fixing part, even if one portion of the shear reinforcing bar 84 is broken, the loss to the tension force is very small, and there is no fear that the tension force cannot be maintained as in the case of PC steel wire.

From the above points, a tensile force is applied to the axial reinforcement 82, and a tensile force is applied to the shear reinforcement reinforcement 84 of the upper flange portion 80 to introduce pre-stress in two directions to the bridge girder E. The bridge girder E is preferably used for a structure such as a three-dimensional road because it has a large strength.

Furthermore, if the anchoring block for introducing prestress in the upper flange portion 80 is made of fiber reinforced plastic, the anchoring block and the shear reinforcing bar 84 can be secured in one piece, and the anchoring block can be used when placing concrete. By embedding it in concrete, the entire shear reinforcing bar 84 can be effectively used as a prestressed concrete member. Therefore, the cutting work and the finishing work can be reduced, and the man-hours can be reduced.

FIGS. 19 to 21 show a fourth embodiment of the present invention, and the symbol F is a bidirectional prestressing concrete member.

This two-way prestressed concrete member (hereinafter abbreviated as concrete member) F has an upper plate portion 90 and a lower plate portion.
A main body 93 having a square cross-section including 91 and both side slabs 92
And an extended portion 90a extending left and right from both sides of the upper plate portion 90, the upper surface formed by the upper plate portion 90 and both extended portions 90a is a slab surface of about 7 m × 7 m Has become.

Inside such a concrete member F, a reinforcing bar group 97 composed of upper and lower shaft bars 94, shear reinforcing bars 95, and anchor bars 96 to which prestress is to be introduced is embedded. The reinforcing bar group 97 includes a cage-shaped upper plate reinforcing bar 97a arranged in the upper plate part 90 and the extending part 90a and a lower plate reinforcing bar 97b arranged in the lower plate part 91.
And the side plate reinforcing bars 97c arranged on both side plate portions 92 and the main body portion 93
Corner reinforcements 97d arranged in each of the 4 corners ...
It is composed of Such a reinforcing bar group 97 is
Similar to the cage-like reinforcing bar 2 of the embodiment, each reinforcing bar made of FRP is integrally molded.

Further, in the width direction of the upper plate portion 90, the shear reinforcing bar 95
Prestress is introduced by applying tensile force to. The method of applying a tensile force to the shear reinforcing bar 95 is the same as that of the bridge girder E of the fourth embodiment.

FIG. 21 shows a usage pattern of such a concrete member F, which is applied to the invention already filed by the applicant as Japanese Patent Application No. 58-252147. As shown in this figure, a plurality of bridge piers 101, 101 are erected on the ground 100, and a prestressed concrete bridge 102 is installed between these piers 101, 101.

This prestressed concrete bridge 102 (hereinafter abbreviated as bridge 102) is composed entirely of a plurality of bridge superstructures (concrete members) F, F ... Introduced with primary prestress. Post tension type secondary pre-stress is introduced by PC steel 103.

To build a bridge 102 like this,
Bridge superstructure F ... is sequentially extended and joined for each block from 1,101 forward and backward. That is, first, the bridge superstructure F already installed on the bridge pier 101 and the second bridge superstructure F suspended from the ground by using a suspension device or the like.
The PC steel material 103a is inserted into the sheaths 98 and 98 on both sides and tensioned to join the bridge superstructures F and F to each other. Then, the PCs are attached to the sheaths 98, 98 of both the second bridge superstructure F and the third bridge superstructure F that are suspended next.
The steel material 103b is inserted and tension work is performed, and those bridge superstructures are
Join F and F together. In this way, the entire bridge 102 is constructed while sequentially joining the bridge superstructures F.

The bridge 102 thus constructed can be used, for example, on its upper surface as a traveling road surface of a magnetic traveling vehicle. In addition, the internal space can be used as a tunnel for wiring such as a cable or a second traveling path. In this case,
As the tension material of the bridge 102, a magnetized material such as carbon fiber is used because the PC steel material 103 may be corroded by the electrolytic corrosion due to magnetism.

According to the concrete member F of this embodiment, as compared with the bridge of the above-mentioned conventional application example, a tension force is applied to the upper and lower sides of the bridge superstructure F to introduce the primary pre-stress.
The strength and durability of 2 can be improved. Further, this makes it possible to set the span length of the bridge 102 to be longer, and it is possible to prevent peeling and cracking of the concrete surface, for example, in a cold region where frost damage easily occurs, and a temperature difference of one day. It is suitable for use in buildings in harsh environments such as severe areas.

Incidentally, each prestressed concrete member as described above, in the basket-like reinforcing bar embedded in concrete, all the intersections of the axial reinforcing bar and the shear reinforcing bar are anchoring parts, but in such a prestressed concrete member However, if at least two intersecting parts are provided on each of the upper and lower axial lines, the fixing effect can be obtained. Therefore, the number of fixing parts (that is, cage shape) can be obtained depending on the size of the member and the usage form. The number of crossing portions in the reinforcing bar) can be set arbitrarily.

"Effects of the Invention" As described in detail above, according to the prestressed concrete member of the present invention, it is utilized that the crossing portion strength of the cage-shaped reinforcing bars formed by integrally fixing continuous fibers with a resin material to form a cage is high. And give tension to the reinforcement,
By using the intersecting portion as a fixing portion, a prestressed concrete member having a higher fixing effect can be obtained. Moreover, since the intersections at a large number of places are used as anchorages, even if part of the reinforcing bar is broken, it is possible to suppress the decrease in tension and effectively prevent peeling and cracking of the concrete surface. You can

Also, according to this manufacturing method, a prestressed concrete member can be easily obtained without the need for a special jig such as the post tension method, the workability thereof can be improved, and mass production can be achieved. Can be easily achieved. In addition, when introducing prestress, the effect of prestress introduction can be enhanced by applying different tensions to the upper and lower sides of the reinforcing muscles. Furthermore, since the anchor blocks that are molded at both ends of the cage reinforcement for introducing prestressing are made of fiber reinforced plastic, it is possible to secure the integrity of the cage reinforcement and the anchor block, and to place concrete By embedding this fixing block in concrete at this time, the entire cage-shaped reinforcing bar can be effectively used as a prestressed concrete member.

Moreover, according to this manufacturing apparatus, different tensions can be applied to one end of the reinforcing bar by at least three jacks, so that the introduction mode of prestress can be arbitrarily set according to the shape of the concrete member and its usage state. Yes,
It is possible to introduce optimal prestress.

[Brief description of the drawings]

1 to 10 show a first embodiment of the present invention. FIG. 1 is a perspective view showing a part of a prestressed concrete member, FIG. 2 is a plan view thereof, and FIG. 3 is a longitudinal section thereof. Fig. 4 is a perspective view showing a part of the cage reinforcement, Fig. 5 is a cross-sectional view of the intersection of the fiber bundles, Fig. 6 is a cross-sectional view of the straight portion of the fiber bundles, and Figs. FIG. 10 is shown for explaining the method for manufacturing the prestressed concrete member. FIG. 7 (a) is a top view of the prestressed concrete member showing fixing blocks at both ends, and (b) is the same front view. FIG. 8 is a configuration diagram of a main part of a fixing block, FIG. 9 is a front view showing a state in which basket-like reinforcing bars are arranged in a manufacturing apparatus,
FIG. 10 is a top view of the same, FIGS. 11 to 15 show a second embodiment of the present invention, FIG. 11 is a perspective view of a prestressed concrete member, and FIG. 12 is II in FIG. 13 is a sectional view taken along the line II-II in FIG. 11,
Figures 14 and 15 show the structure of concrete reinforcement bars,
FIG. 16 is a block diagram showing a state in which the prestressed concrete member in the second embodiment is used as a beam for supporting a floor slab,
FIG. 17 is a third embodiment of the present invention, and is a configuration diagram showing a state in which a prestressed concrete member is used as a footing of a marine structure, and FIG. 18 is a fourth embodiment of the present invention.
The block diagram which shows the state which used the prestressed concrete member for the bridge girder of an elevated road, FIG. 19 thru | or 21 is 5th Example of this invention, FIG. 19 is sectional drawing of the prestressed concrete member, FIG. Is a perspective view thereof, and FIG. 21 is a configuration diagram showing a state in which the prestressed concrete member is used for a bridge superstructure. 1 …… Concrete, 2,44 (44a, 44b, 44c), 61 (61a, 61b), 83 (83a, 83b, 83c), 97 (97a, 97b, 97c) …… Cage-shaped reinforcement, 3,45 , 62, 82, 94 …… Axial reinforcement, 4, 46, 63, 83, 95 …… Shear reinforcement, 10 …… Resin, 11 …… Continuous fiber, 20 …… Formwork, 21 …… Base, 23 …… Fixed block, 27 …… Jack, 30 (30a, 30b, 30c) …… Fixing block, A, B, C, D, E, F …… Prestressed concrete members.

Continuation of the front page (56) References JP 62-185946 (JP, A) JP 63-11747 (JP, A) JP 64-6442 (JP, A)

Claims (4)

(57) [Claims] 1. A prestressed concrete member comprising concrete and a basket-like reinforcing bar embedded in the concrete and having an axial bar and a shear reinforcing bar, wherein the axial bar is given a tensioning force. The cage-shaped reinforcing bar is a prestressed concrete member characterized in that continuous fibers impregnated with resin are formed integrally by being crossed in one direction and in a direction orthogonal thereto. 2. The prestressed concrete member according to claim 1, wherein at the intersection of the axial reinforcement and the shear reinforcement, continuous fibers constituting the intersection are alternately laminated in three or more layers. 3. A step of integrally forming a cage-shaped reinforcing bar having axial reinforcement and shear reinforcing reinforcement by crossing resin-impregnated continuous fibers in one direction and in a direction orthogonal thereto, and introducing prestress. Forming a fixing block made of fiber reinforced plastic at both ends of the cage-like reinforcing bar to be formed, the cage-like reinforcing bar, and a step of arranging the cage through the frame of the prestressed concrete member to be formed, The step of taking the reaction force of the jack with the fixing block and applying different tension to the upper and lower axial lines by the jack, and placing concrete in the formwork, the placed concrete has reached the required strength. After that, the method of manufacturing a prestressed concrete member, which comprises the steps of loosening the jack and cutting the cage-shaped reinforcing bars and fixing blocks located outside the mold. 4. A formwork through which the cage-shaped reinforcing bar according to claim 1 is arranged, a base on which the formwork is placed, and a shaft bar of the cage-shaped reinforcing bar provided on the base. Apparatus for manufacturing a prestressed concrete member, comprising: a fixing block fixing at least one end thereof; and at least three jacks which are three-dimensionally provided on the base and apply a tension force to at least the other end of the axial reinforcement of the cage reinforcement. .