JP6918469B2 - Construction method of precast member, erection structure of precast member, erection structure of precast member - Google Patents

Description

The present invention relates to a precast member and its erection structure and the like.

The precast prestressed concrete structure (hereinafter referred to as PCaPC structure) is a structure in which prestress is introduced into a precast member made of concrete, and is used in various structures.

For example, Patent Document 1 describes an example in which both members are pressure-bonded by introducing prestress into a tension material passed through a precast concrete beam and a precast concrete column. Such a PCaPC structure can be constructed by erection of a precast member manufactured in a factory or the like at a site, and then passing a tension material through a hole of the precast member to perform tensioning by a jack or grouting the hole.

In Patent Document 2, in a precast concrete beam in which prestress by a tension material is introduced at a factory, the end portion of the tension material is extended from the beam end face, and after the precast concrete beam is erected at the site, it is placed on both sides of the precast concrete beam. It is described that the precast concrete beam and the column are crimp-joined by constructing a column in which the extension portion of the tension material is embedded, and finally tensioning the extension portion and fixing it to the side surface of the column.

Japanese Patent Application Laid-Open No. 2002-4417 Japanese Unexamined Patent Publication No. 2007-191865

As described above, in the conventional PCaPC structure, the tensioning material is often tensioned after the precast member is erected to introduce prestress, and it is necessary to carry the jack to the erection position of the precast member to perform the tensioning work. However, the jack is a heavy object, and its movement, tension work, and withdrawal are troublesome. In addition, with the conventional method, it is not possible to proceed to the next process unless the tension work is completed, which has become a bottleneck for shortening the construction period. Furthermore, the tense work was a professional work and was also a dangerous work.

Further, when joining precast members by the PCaPC structure, cracks at the boundary between the members to be joined often become a problem, and it is also required to prevent such cracks while facilitating the construction.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a precast member or the like that facilitates construction and can prevent cracks.

The first invention for solving the above-mentioned problems is a precast member into which prestress by a tension material is introduced , and a bearing body which is a tubular body is provided so as to protrude from the end face of the precast member. The pressure bearing body is arranged without being fixed to the end face of the precast member, and at the tip end portion of the pressure bearing body, constitutes a fixing portion in which the end portion of the tensioning material is fixed to the tip end portion of the pressure bearing body. The precast member is provided with a wedge-shaped grip, the pressure bearing body is crimped to the precast member by the fixing portion, and a filler is filled between the pressure bearing body and the tension member. ..

Since the precast member of the present invention is prestressed by a tensioning material in advance, tensioning work and grouting work after erection are not required, and construction is easy. Can be constructed. Further, by arranging the bearing body without fixing it to the end face of the precast member and fixing the end portion of the tension material to the bearing body, the bearing body acts as an anchor in which the restoring force due to the prestress of the tension material works. It works and can have extremely few cracks. As a result, it leads to improvement of quality of PCaPC structure, improvement of safety during construction, shortening of construction period, and cost reduction.

It is desirable that the tensioning material is an unbonded PC steel material.
As a result, the restoring force due to prestress can be preferably applied .

It is desirable that the tip portion of the pressure bearing body is widened.
As a result, the bearing body functions as an anchor capable of more preferably transmitting stress.

The second invention is a precast member into which prestress by a tension material is introduced, and a bearing body formed in a reinforcing bar cage shape is provided so as to project from the end face of the precast member, and the bearing body is provided. Is arranged without being fixed to the end face of the precast member, and at the tip portion of the bearing body, a wedge-shaped grip constituting a fixing portion for fixing the end portion of the tensioning material to the tip portion of the bearing body is provided. It is a precast member provided and characterized in that the pressure bearing body is crimped to the precast member by the fixing portion .
As a result, the fixing effect of the pressure bearing body as an anchor can be enhanced, and there is also an advantage that the pressure bearing body can be formed at low cost.

In the third invention, the end portion of the precast member of the first or second invention is arranged on the support, a solidifying material is provided on the support, and the solidifying material is subjected to the bearing pressure of the precast member. It is an erection structure of a precast member characterized in that the body is buried.

In the third invention, the precast member is a beam, the precast member has a plurality of the tension members and the pressure bearing body, and a steel frame member having a flange is arranged between the adjacent pressure bearing bodies. It is also desirable.
As a result, the compressive force applied from the bearing body as an anchor can be received by the flange of the steel frame member and transmitted to the steel frame member, and the reinforcing effect is improved. Therefore, the length of the bearing body can be shortened, which is advantageous in terms of cost and fit.

In the fourth invention, the end portion of the precast member of the first or second invention is arranged on a support, a solidifying material is provided on the support, and the solidifying material is subjected to the bearing pressure of the precast member. It is a method of constructing an erection structure of a precast member, which is characterized by burying a body.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a precast member or the like that facilitates construction and can prevent cracks.

The figure which shows the erection structure 100 of the precast member 1. The figure which shows the anchor part 12. The figure which shows the restoring force of an anchor part 12. The figure explaining the construction method of the erection structure 100 of the precast member 1. The figure explaining the construction method of the erection structure 100 of the precast member 1. The figure which shows the arrangement example of the anchor part 12. The figure which shows the arrangement example of the anchor part 12. The figure which shows another arrangement example of the anchor part 12. The figure which shows the cross H steel 40. The figure which shows the erection structure 100a of the precast member 1a. The figure which shows the precast member 1b. The figure which shows the precast member 1c. The figure which shows the precast member 1c'.

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

[First Embodiment]
(1. Precast member 1 and its erection structure 100)
FIG. 1 is a diagram showing an erection structure 100 of the precast member 1 according to the first embodiment of the present invention.

The erection structure 100 is a PCaPC structure in which a beam made of a prestressed concrete precast member 1 is laid between columns 3 (supports).

In the erection structure 100, the ends of the pair of precast members 1 are placed on both sides of the panel zone (column-beam joint) on the column 3, and the concrete 2 (solidification) is placed between the opposing end faces of the pair of precast members 1. It is formed by casting the material) in the field.

Prestress by the tension member 11 is introduced into the precast member 1. A PC steel material such as a PC steel wire is used for the tension material 11, and the tension material 11 is arranged so as to penetrate the beam axial direction of the precast member 1. In this embodiment, an unbonded PC steel material coated with grease or the like is used as the tension material 11.

An anchor portion 12 is provided on the end surface of the precast member 1, and the anchor portion 12 is embedded in the concrete 2 of the panel zone. The anchor portion 12 is a stress transmission fitting for transmitting stress between the precast member 1 and the concrete 2.

Although the details will be described later, in the present embodiment, the end portion of the tension member 11 is passed through the anchor portion 12 and fixed by the anchor portion 12. Further, in addition to the anchor portion 12, reinforcing bars and hoop reinforcing bars protruding from the precast member 1 and columns 3 are also embedded in the concrete 2 of the panel zone, but the illustration of these reinforcing bars is omitted in FIG. There is. This also applies to the following figures.

FIG. 2 is a diagram showing an anchor portion 12. In the present embodiment, the anchor portion 12 is composed of a tubular body 121 (supporting body), a filler 124, a fixing portion 125, a sheath 127, and the like.

The tubular body 121 is a rigid metal tubular member, and a steel pipe or the like is used. The tubular body 121 is arranged so as to project from the end face of the precast member 1. An annular plate such as a steel plate is attached to the root portion 121a and the tip portion 121b of the tubular body 121 to form a flange-shaped widened portion. The root portion 121a of the tubular body 121 is arranged along the end surface of the precast member 1. A fixing portion 125 is provided on the tip portion 121b.

A sheath 127 made of a resin such as polyethylene is arranged inside the cylinder 121, and the end portion of the tension member 11 is passed through the sheath 127. The gap between the inner peripheral surface of the cylinder 121 and the sheath 127 is filled with a filler 124 such as high-strength concrete. In the concrete of the precast member 1, the tension material 11 is passed through the same sheath 13 as the sheath 127 described above.

The end portion of the tension member 11 passes through the tip end portion 121b of the tubular body 121, and the tip end thereof is fixed to the fixing portion 125. The fixing portion 125 is composed of a wedge-shaped grip 125a for fixing the tension material 11 and a holder 125b or the like for holding the grip 125a, and has a hole for passing the tension material 11. The tip of the tension member 11 in the tense state is fixed to the fixing portion 125, and the tip of the tension member 11 is fixed to the tip portion 121b of the cylinder body 121 by the fixing portion 125, so that the cylinder body 121 is fixed to the precast member 1 side. It is pressed against and both members are crimped.

However, in the present embodiment, the root portion 121a of the tubular body 121 is not fixed to the end surface of the precast member 1, and the tubular body 121 and the precast member 1 are not integrated. Therefore, the anchor portion 12 and the precast member 1 are relatively rotatable.

In the erection structure 100 of FIG. 1, when the frame is deformed so that the boundary between the precast member 1 and the concrete 2 is likely to crack as shown in FIG. 3 due to a large earthquake or the like, the prestress of the tension member 11 indicates the arrow A. As described above, the resistance force (restoring force) against the deformation can be exerted, and cracks can be prevented.

If the root portion 121a of the tubular body 121 is fixed to the precast member 1, the tubular body 121 may be deformed due to the above deformation, which may hinder the exerting of the restoring force due to the prestress of the tension member 11. ..

(2. Method for constructing the erection structure 100 of the precast member 1)
Next, a method of constructing the erection structure 100 of the precast member 1 will be described with reference to FIGS. 4, 5, and the like.

In the present embodiment, the precast member 1 into which the prestress by the tension material 11 is introduced is manufactured in advance at a factory or a site.

At this time, first, as shown in FIG. 4A, the tension member 11 is wired in the sheath 13, and the formwork (not shown) is provided so that the tension member 11 and the ends of the sheath 13 project from the end faces of the precast member 1. ) And the like to cast the concrete of the precast member 1. Other necessary reinforcing bars and the like (not shown) are also embedded in the concrete of the precast member 1, and if necessary, the ends of the reinforcing bars and the like are also projected from the end faces of the precast member 1.

After the concrete is solidified, the formwork is removed, and the end portion of the sheath 13 protruding from the precast member 1 is cut and removed. Then, as shown in FIG. 4B, the end portion of the tension member 11 protruding from the precast member 1 is passed through the sheath 127 of the tubular body 121, and the root portion 121a of the tubular body 121 is passed along the end surface of the precast member 1. And place it. In this example, the tubular body 121 is pre-filled with the filler 124, but the filler 124 may be filled after the end portion of the tension member 11 is passed through the sheath 127.

Then, as shown in FIG. 4C, the fixing portion 125 through which the tip of the tension member 11 is passed is set on the tip portion 121b of the tubular body 121, and the tip of the tension member 11 is tensioned by the jack 30. The tension material 11 is fixed to the fixing portion 125.

When the tension of the tension material 11 is released, the tension material 11 is fixed to the tip portion 121b of the tubular body 121 by the fixing portion 125. When the extra length of the tension member 11 protruding from the fixing portion 125 is cut, the production of the precast member 1 is completed as shown in FIG. 5 (a).

After that, as shown in FIG. 5B, the precast member 1 is arranged with the end portion placed on the panel zone on the pillar 3. In this way, the precast members 1 are erected on both sides of the panel zone, and concrete 2 is cast in the panel zone as shown in FIG. 5 (c) to construct the erection structure 100 of the precast members 1 shown in FIG. After the concrete 2 has solidified and developed strength, stress can be transmitted by the anchor portion 12.

(3. Arrangement example of anchor portion 12)
FIG. 6 is a diagram showing an arrangement example of the anchor portion 12 on a plane, and FIGS. 7 (a) and 7 (b) are views showing vertical cross sections taken along the lines BB and CC of FIG. 6, respectively.

In this example, the pair of precast members 1 sandwiching the panel zone in the horizontal direction and the pair of precast members 1'sandwiching the panel zone in the vertical direction each have a plurality of rows in a plane (two rows in the example of FIG. 6). Has a tension member 11 and an anchor portion 12. Further, when viewed in the vertical direction, as shown in FIGS. 7A and 7B, there are a plurality of stages of the precast members 1 and 1'(3 stages in the example of the precast member 1 of FIG. 7A), FIG. 7 ( In the example of the precast member 1'of b), the tension member 11 and the anchor portion 12 of 2 steps) are arranged.

Here, the anchor portions 12 of the pair of precast members 1 in the lateral direction are arranged so that the tips thereof abut against each other in the panel zone.

With respect to the pair of precast members 1'in the vertical direction, the upper portion of the end portion on the panel zone side is cut out in a substantially U-shape in a plan view. The anchor portion 12 is arranged so as to protrude from the notch portion 16. The notch 16 is filled with concrete 2 in the panel zone, and the tip of the anchor portion 12 is located on the side of the anchor portion 12 of the pair of precast members 1 in the lateral direction described above.

FIG. 8 is a diagram showing another arrangement example of the anchor portion 12, and in this example, a pair of precast members 1, 1 ”sandwiching the panel zone in the vertical direction are arranged in a plurality of rows (2 in the example of FIG. 8). It has a tension member 11 and an anchor portion 12 (row). In this example, a pair of ordinary reinforced concrete beams 20 are provided so as to sandwich the panel zone in the lateral direction.

The end of one precast member 1 "on the panel zone side is widened in a reverse taper shape, so that the two rows of tension members 11 of the precast member 1" widen the distance between the tension members 11 at this widened portion. It is arranged to be inclined outward. In the panel zone, the anchor portion 12 of the precast member 1 ”is arranged so as to sandwich the anchor portion 12 of the other precast member 1.

As described above, since the precast member 1 of the present embodiment is prestressed by the tension material 11 in advance, tension work and grout work after erection are not required, and the construction becomes easy, and the construction becomes easy at the factory or the site. A long-span erection structure 100 can be constructed using the manufactured precast member 1. Further, by arranging the tubular body 121 without fixing it to the end face of the precast member 1 and fixing the end portion of the tension member 11 to the tubular body 121, the tubular body 121 exerts a restoring force due to the prestress of the tension member 11. It functions as a working anchor and can reduce cracks extremely. As a result, it leads to improvement of quality of PCaPC structure, improvement of safety during construction, shortening of construction period, and cost reduction.

Further, by using an unbonded PC steel material for the tension material 11, it is possible to cut off the adhesion in the anchor portion 12 and appropriately exert the restoring force due to prestressed concrete. It is possible to configure the anchor portion 12 so that the filler 124 and the tensioning material 11 adhere to each other, but in this case as well, it is desirable that the adhesion is cut off in the case as shown in FIG.

Further, in the present embodiment, since the tip portion 121b of the tubular body 121 is widened, the tubular body 121 functions as an anchor capable of more preferably transmitting stress.

However, the present invention is not limited to this. For example, as shown in FIG. 9, by arranging the flange 41 of the cross H steel 40 between the cylinders 121 of the adjacent anchor portions 12 of the precast member 1, it is possible to improve the reinforcing effect of the anchor portion 12. be.

The cross H steel 40 is a steel frame member having a flange 41, and has a shape in which H-shaped steels are crossed in a plane cross shape. The height of the top end of the cloth H steel 40 is about the same as the height of the top end of the precast member 1 and the reinforced concrete beam 20. The lower portion of the cloth H steel 40 may be embedded in the pillar 3 below the panel zone, or may be simply placed on the upper surface of the pillar 3.

When the deformation as described with reference to FIG. 3 occurs in the frame, the compressive force from the tip portion 121b of the tubular body 121 of the anchor portion 12 and the compressive force from the concrete 2 adhering to the tubular body 121 are the dotted lines in FIG. Although it is added to the range indicated by F, in the example of FIG. 9, this compressive force is received by the flange 41 of the cross H steel 40 and can be transmitted to the cross H steel 40. Therefore, the reinforcing effect of the anchor portion 12 is improved, and the length of the tubular body 121 can be shortened, which is advantageous in terms of cost and fit.

Although the cross H steel 40 is used in the example of FIG. 9, for example, there is a beam only at a position sandwiching the panel zone in one direction, and a precast member 1 having an anchor portion 12 is used for the pair of beams. Then, ordinary H-shaped steel may be used as a steel frame member instead of the cross H-steel 40. In this case, both flanges of the H-shaped steel are arranged so as to come between the cylinders 121 of the anchor portion 12 of both precast members 1.

Hereinafter, another example of the present invention will be described as the second to fourth embodiments. The points of each embodiment different from those of the first embodiment will be described, and the same points will be omitted by adding the same reference numerals in the drawings and the like. In addition, the configurations described in each embodiment, including the first embodiment, can be combined as needed.

[Second Embodiment]
FIG. 10A is a diagram showing an erection structure 100a of the precast member 1a according to the second embodiment of the present invention. This erection structure 100a is different from the first embodiment in that it is a PCaPC structure in which a floor slab made of a prestressed concrete precast member 1a is bridged between beams 5 (supports).

The erection structure 100a is formed by placing the ends of a pair of precast members 1a on both sides of the beam 5 and casting concrete 2a (solidifying material) between the opposing end faces of the pair of precast members 1a. NS. A plurality of precast members 1a are arranged side by side in the beam axial direction of the beam 5 (corresponding to the paper surface normal direction in FIG. 10A), whereby a slab is constructed.

FIG. 10B is a diagram showing an example of arrangement of the anchor portion 12 on a plane. As shown in the figure, the precast member 1a has a plurality of rows (4 rows in the example of FIG. 10B) of tension members 11 and anchor portions 12 in a plane, and the anchor portion 12 of one precast member 1a is the other. It is arranged between the anchor portions 12 of the precast member 1a.

As described above, by using the precast member 1a as the floor slab in the present embodiment, the same effect as that of the first embodiment can be obtained in the PCaPC structure including the floor slab. The joint between the floor slab and the top of the beam is originally a place where cracks are likely to occur, but by using the above-mentioned precast member 1a, cracks can be prevented, and a great effect can be expected.

In the present embodiment, the entire floor slab is used as the precast member 1a, but the precast member 1a may be used as the half precast floor slab, and the floor slab may be constructed together with the cast-in-place concrete.

[Third Embodiment]
FIG. 11 is a diagram showing a precast member 1b according to a third embodiment of the present invention. The precast member 1b is different from the first embodiment in the shape of the anchor portion 14.

That is, the anchor portion 14 of the present embodiment is configured by providing a sheath 142 inside a rigid metal cylinder 141 (supporting body) formed by casting or the like, and is filled as in the first embodiment. The material is omitted. Further, ribs (convex portions) 141c are provided on the outer peripheral surface of the tubular body 141, and the ribs 141c function as an anchor that allows the tubular body 141 to more preferably transmit stress.

The root portion 141a of the tubular body 141 is widened in a flange shape and is not fixed to the end face of the precast member 1b as in the first embodiment. On the other hand, the tip portion 141b of the tubular body 141 is widened in a reverse taper shape, and the hole of the tubular body 141 is also widened in a reverse taper shape at the tip portion 141b. A fixing portion 143 is arranged in this reverse taper portion. The fixing portion 143 is a wedge-shaped grip or the like.

The end portion of the tension member 11 protruding from the precast member 1b passes through the sheath 142 of the tubular body 141, and the tip thereof is fixed to the fixing portion 143 in a tensioned state as in the first embodiment of the tubular body 141. It is fixed to the tip portion 141b. This precast member 1b can also be used in the same manner as in the first embodiment, and the same effect as in the first embodiment described above can be obtained.

[Fourth Embodiment]
12 (a) is a diagram showing a precast member 1c according to a fourth embodiment of the present invention, and FIG. 12 (b) is a diagram showing a cross section taken along line DD of FIG. 12 (a), FIG. 12 (b). c) is a side view of the anchor portion 15 of the precast member 1c.

The precast member 1c of the fourth embodiment is also different from the first embodiment in the shape of the anchor portion 15. That is, the anchor portion 15 is composed of a reinforcing bar 151, a spiral bar 152, a plate 153, 154, a fixing portion 155, a sheath 156, and the like.

Reinforcing bars 151 are steel materials arranged along the longitudinal direction of the tension member 11, and are provided at four locations around the tension member 11 in the present embodiment.

An annular plates 153 and 154 such as steel plates are attached to the root portion and the tip portion of the reinforcing bar 151. The plate 153 on the root side is arranged along the end face of the precast member 1c, but is not fixed to the end face as in the first embodiment. On the other hand, the hole 1541 of the plate 154 on the distal end side expands in a reverse taper shape, and the fixing portion 155 is arranged in this hole 1541. The fixing portion 155 is a wedge-shaped grip or the like.

The spiral bar 152 is spirally provided around the reinforcing bar 151, and is welded and fixed to the reinforcing bar 151. The spiral bar 152 is provided to reinforce the reinforcing bar 151 and prevent buckling.

The end portion of the tension member 11 protruding from the precast member 1c passes through the sheath 156 arranged inside the reinforcing bar 151, and the tip thereof is fixed to the fixing portion 155 in a tensioned state as in the first embodiment. Is fixed to the plate 154. The reinforcing bars 151, the plates 153, 154 and the spiral reinforcing bars 152 of the anchor portion 15 form a reinforcing bar cage-like bearing body that supports the prestressing force of the tension member 11.

This precast member 1c can also be used in the same manner as in the first embodiment, and the same effect as in the first embodiment described above can be obtained. Further, since concrete can be filled inside the spiral bar 152, the fixing effect of the anchor portion 15 is enhanced and stress can be easily transmitted. Further, there is an advantage that the anchor portion 15 can be formed at a lower cost than the anchor portions 12 and 14 described above.

FIG. 13 (a) is a modification of the anchor portion 15 of the precast member 1c described above. It is connected by a connecting means. As a result, the reinforcing effect of the anchor portion 15a can be enhanced. Note that FIG. 13B is a view showing a cross section taken along line EE of FIG. 13A. In this example, the four corners of the plate 154a are connected by screw reinforcing bars 31, nuts 32, and the like.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

1, 1', 1 ", 1a, 1b, 1c, 1c': Precast members 2, 2a: Concrete 3: Pillar 5: Beam 11: Tension material 12, 14, 15, 15a: Anchor portion 13, 127, 142, 156: Sheath 16: Notch 20: Reinforced concrete beam 30: Jack 31: Screw Reinforcing bar 32: Nut 40: Cross H steel 41: Flange 100, 100a: Elevation structure 121, 141: Cylinder 121a, 141a: Root part 121b, 141b : Tip portion 124: Filling material 125, 143, 155: Fixing portion 141c: Rib 151: Reinforcing bar 152: Spiral reinforcing bar 153, 154, 154a: Plate

Claims (6)

It is a precast member with prestress introduced by tension material.
A pressure bearing body, which is a tubular body, is provided so as to project from the end face of the precast member.
The pressure bearing body is arranged without being fixed to the end face of the precast member.
At the tip portion of the pressure bearing body, a wedge-shaped grip forming a fixing portion for fixing the end portion of the tension material to the tip end portion of the pressure bearing body is provided.
The pressure bearing body is crimped to the precast member by the fixing portion, and the pressure bearing body is pressed against the precast member .
A precast member characterized in that a filler is filled between the pressure bearing body and the tension member. It is a precast member with prestress introduced by tension material.
A bearing body formed in a reinforcing bar cage shape is provided so as to project from the end face of the precast member.
The pressure bearing body is arranged without being fixed to the end face of the precast member.
At the tip portion of the pressure bearing body, a wedge-shaped grip forming a fixing portion for fixing the end portion of the tension material to the tip end portion of the pressure bearing body is provided.
A precast member characterized in that the pressure bearing body is pressed against the precast member by the fixing portion. The precast member according to claim 1, wherein the tip portion of the pressure bearing body is widened. The end of the precast member according to any one of claims 1 to 3 is arranged on the support.
An erection structure of a precast member, characterized in that a solidifying material is provided on the support and the pressure bearing body of the precast member is embedded in the solidifying material. The precast member is a beam
The precast member has a plurality of the tensioning material and the pressure bearing body.
The erection structure of a precast member according to claim 4 , wherein a steel frame member having a flange is arranged between adjacent pressure bearing bodies. The end of the precast member according to any one of claims 1 to 3 is arranged on the support.
A method for constructing an erection structure of a precast member, which comprises providing a solidifying material on the support and embedding the pressure bearing body of the precast member in the solidifying material.

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