JP3013355B2 - Pretension type PC member formwork - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretension type PC member formwork.

[0002]

Conventionally, this type of pretension type PC (prestressed concrete) member, for example, a PC used for a main girder of a prefabricated PC cover or a main girder of a shed for road protection, which is a rock fall protection body. As shown in FIG. 8, the spar is composed of a flange portion 1, a web portion 2, and a cross beam portion 3.
And pretension is given by the PC steel material 4. By the way, in order to mold the conventional PC girder into concrete by the pretension method, first, a P
The C steel material 4 is arranged and tension is applied. Then, concrete is poured into a formwork, and after hardening, the tension is released to give a prestress to the concrete. I was going. For this reason, a compressive force acts on the concrete molded product by releasing the tension and giving a prestress, and the flange portion 1 and the web portion 2 contract in the direction of the PC steel material 4, that is, the longitudinal direction,
In the case of a structure having a plurality of cross beams 3 as shown in FIG. 8, the compressive force causes the inner side surfaces 5 of the cross beams 3 on both sides in the vertical direction to press against the formwork, making it difficult to remove the mold. 3
There is a problem of damaging the inner side surface 5 of the device.

For this reason, if the inner side surface 5 of the cross beam portion 3 is formed at an acute angle with respect to the length direction, the die can be relatively smoothly removed, but the cross section of the cross beam portion 3 is structurally unnecessary. Since the number of parts increases, there is a problem that the parts cause loss of material cost.

Further, after the concrete has hardened to a predetermined strength, the PC girder is slightly lifted while the PC steel material 4 is pulled and held by a tensioning device, and a spacer is interposed between the PC girder and the form. Thus, a method is also known in which after a gap is formed between the cross beam portion 3 and the formwork, the tension force of the tensioning device is released. But with this method,
Since the PC girder is lifted against the PC steel 4 in a state where the PC girder 4 is pulled and held, the lifting work becomes complicated. In addition, in order to evenly lift a relatively long PC girder, an operation such as a crane is required. There is a problem that is difficult.

[0005] Further, in the case of using this type of integral formwork, in addition to the prestressed by the PC steel material, concrete hardening causes a contraction in the vertical direction due to the hardening of the concrete. There is a problem that press contact occurs between the mold and the mold, and the press contact makes it difficult to remove the mold.

In view of the above, the present invention provides a concrete molded product having a plurality of cross beams on one side, in the case where a longitudinal prestress is applied, to prevent local damage to the cross beams,
It is an object of the present invention to provide a pretension type PC member mold excellent in mold removal workability and easy to handle the mold.

[0007]

According to a first aspect of the present invention, there is provided a mold for manufacturing a PC member having a plurality of cross beams on one side and pretensioning in a longitudinal direction. The inner plate at the location is detachably provided from the formwork position, and after the concrete is hardened, by removing the inner plate from the formwork position, even if the PC member shrinks, the inside of the cross beam portion and the formwork is formed. There is no pressure contact with the plate.

According to a second aspect of the present invention, the inner plate is rotatably provided on the mold, and the inner plate is rotated to be removed from the mold position. To return to the mold position.

According to a third aspect of the present invention, a joining flange is provided at a joint between the inner plate and the mold, and the joining and removal of the inner plate to and from the mold are performed by the joining flange. .

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 to 3 show a first embodiment of the present invention. The same parts as those in FIG. 8 are denoted by the same reference numerals, and the PC member shown in FIG.
Is a steel PC girder formwork (hereinafter referred to as a formwork). This formwork 10 has a vertical flange forming section 11, a web forming section 12, and a horizontal crossbeam section, ie, three horizontal beam sections. Parts 13, 13,
For example, if the PC girder constitutes the roof of the rock fall protection body, the cross beam forming portion 13A forms the mountain-side horizontal beam portion 3, and the left horizontal beam forming portion 13 in FIG. Side beam part 3 is formed. Further, the flange molding portion 11
In this example, a lower surface portion 11A forming the lower surface of the flange portion 1 is provided integrally with the formwork 10, and a side plate portion 14 separate from the formwork 10 is detachably provided around the lower surface portion 11A. The side surface portion 14 is formed by providing the angle iron 14A with a fixing member 14B such as a bolt and a nut.

On the left and right sides of the bottom plate 15 of the web forming section 12,
Vertical cut portions 16, 16 are formed at the cross beam forming portions 13, 13, and the cut portions 16 are formed longer than the corresponding cross beam forming portions 13, 13. Further, as shown in FIGS. 1 and 3, the mold 10 is cut vertically from an end of each cutting portion 16 to form a mold cutout portion 17, and the form cutout portion 17 is formed with a cross beam. Department
13 and 13, inner side plates 18 and 18A on both sides in the longitudinal direction are provided, thereby forming a form cutout 17 including at least the inner side plate 18. The inner plates 18, 18A form the inner surfaces 5, 5. Cutting section 19 obtained by cutting the formwork 10 in the vertical direction
Is a joining portion between the form cutout portion 17 and the formwork 10, and each joining portion has a joining flange portion (hereinafter, referred to as a flange portion).
10A and 17A are provided. The flange portion 10A is provided on the formwork 10, and the flange portion 17A is provided on the formwork cutout portion 17. Further, a joint hole 20 is formed in the flanges 10A and 17A, and a bolt 21 for fastening and fixing the overlapping flanges 10A and 17A is inserted into the joint hole 20.
A nut 22 is screwed into the fixing member 23, and the bolt 21 and the nut 22 constitute a fixing member 23. The form cutting portion 17 is rotatably provided on the bottom plate 15, and an attachment portion 24 is integrally provided on the lower surface of the bottom plate 15, and an arm portion is provided on the lower surface of the form cutting portion 17 in the lateral center side. 25 base end is provided integrally, this arm part 25
2 is rotatably connected to the mounting portion 24 by a vertical pivot 26. As shown in FIG. 2, a pair of arm portions 25, 25 are provided. In this example, the cross beam forming portion 13A is a fixed forming portion. An outer plate 32 is detachably fitted on the laterally outer side of the horizontal beam forming portions 13, 13, 13A.

[0012] However, by the pretension method, the PC
In order to form a girder, first, as shown in FIG. 2, a PC steel material 4 such as a PC steel wire is placed on a mold frame 10 and tension is applied by a conventional method. Thereafter, concrete is poured into the formwork 10 and the concrete is hardened while tension is applied to the PC steel material 4. After that, the angle iron 14A is removed and the fixing member 23 is removed. Then, as shown in FIG.
The form cutout portions 17 on both sides in the lateral direction are pivoted downward around the center and removed from the form position. In this case, the angle iron
With the 14A attached to the lower surface 11A, the form cutout 17 may be rotated. In this manner, after removing the form cut-out portion 17 forming the cross beam portion 3 from the form position, the tension of the PC steel material 4 is released, and the PC member 27 is lifted and demolded. In this case, before the PC member 27 is prestressed, the inner plates 18 and 18A are removed from the form position, so that PC
Even if the tension of the steel material 4 is released, the PC member
The PC member 27 can be easily removed from the mold without pressing the inner side surface 5 of the 27. Then, in order to assemble the formwork 10, the formwork cutout portion 17 is rotated upward, and the flange portions 10A, 17
A bolt 21 is inserted into the joint holes 20 and 20 of A, and a nut 22 is fastened to the bolt 21 to fix the joint.

As described above, in this embodiment, a plurality of cross beams 3, 3, 3 are provided at a lower portion on one side according to the first aspect.
In a mold for manufacturing a PC member 27 provided with a pretension in the vertical direction, a mold cutting portion 17 is cut out from the mold 10 so that the inner plate 18 at the cross beam portion of the mold 10 is Since it is provided so that it can be removed from the position, even if the PC member 27 shrinks after hardening of the concrete, the cross beam part 3 and the inner plate 18 of the formwork 10 do not come into pressure contact with each other, and the demolding can be performed smoothly. The inner surface 5 of the cross beam 3 can be
Is not damaged or damaged by friction or the like. Further, since it is not necessary to form a structurally unnecessary portion in the cross section of the cross beam portion 3, there is no loss of material cost, and the dead weight does not increase due to the extra portion.

As described above, according to the present embodiment, claim 2
In response to the above, while cutting out the form cutout part 17 from the formwork 10,
By providing the form cutout 17 in the form 10 in a rotatable manner, the inner plate 18 is provided in the form 10 in a rotatable manner. After removal from the mold and removal from the mold, the inner plate 18 can be rotated in the reverse direction to return to the mold position, and without removing the inner plate 18 from the mold 10, detachment and return can be performed by a rotating operation. Because
The work of the mold 10 can be performed smoothly.

Further, as described above, according to the present embodiment, the joining flanges 17A and 10A are respectively provided at the joining portions between the mold cutout portion 17 including the inner plate 18 and the mold 10. Since it is provided, the joining and removal of the inner plate 18 to and from the mold 10 can be easily performed by the joining flanges 17A and 10A.

Also, as an effect of the embodiment, the portion between the cut portions 16 on both sides in the lateral direction of the bottom plate 15 remains in the mold 10, so that even if the PC member 27 contracts, The return of rotation of the formwork cutout 17 can be performed smoothly without changing the vertical dimension of the frame. Also, the pivot 26 is attached to the bottom plate 15 by the mounting portion 24.
Since it is provided at a position separated from the lower surface of the web, the inner surface of the form cutout 17 can be smoothly separated from the outer surface of the web portion 2.

FIG. 4 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. An example is shown in which both side flanges 17A, 17A of the protrusion 17 are obliquely attached so as to form a C-shape toward the tip.
Corresponding to A, the flanges 10A, 10A are also obliquely attached to the formwork 10.

By mounting the flanges 17A and 10A obliquely in this manner, the overlapping flanges 17A and 10A do not slide when the form cut-out portion 17 rotates downward. Also, the position can be adjusted smoothly even when returning by turning upward.

FIGS. 5 and 6 show a third embodiment of the present invention. The same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Bottom plate
31 is cut substantially parallel to the inner side plate 18 to cut a cross beam 33
The lower surface portion 11A is cut obliquely in a plane to form a lower surface cut portion 34, and the outer plate 35 of the web portion 12 is cut in a vertical direction to form a vertical cut portion 36. The section 36 and the cross beam cutting section 33 are connected by a length direction cutting section 37, and a form cutting section 38 is cut from the form 10. In addition, a flange 17B is provided at 33 of the horizontal beam cutting portion of the form cutting portion 38, and a flange is provided at the lower surface cutting portion 34 and the vertical cutting portion 36.
17C, and as shown in FIG.
Are provided diagonally on both sides in the vertical direction. These flanges 17B, 17C
Corresponding to the flanges 10B, 10B having substantially the same shape as the flanges 17B, 17C.
C is provided on the mold 10.

[0020] However, by the pretension method, the PC
In order to mold the girder, concrete is poured into the formwork 10 and the concrete is hardened while tension is applied to the PC steel material 4 and then fixed from the flanges 17B, 10B and the flanges 17C, 10C. The member 23 is removed, and the mold cutout portion 38 is pulled out from the mold 10 while being pulled down diagonally downward, and is removed. In this way, after removing the form cut-out portion 38 forming the vicinity of the inner side surface 5 from the form position, the tension of the PC steel material 4 is released, and the PC
The member 27 is lifted and removed. In this case, by removing the inner plate 18 before prestressing the PC member 27, even if the tension of the PC steel material 4 is released, the inner plate 18
The PC member 27 can be easily removed from the mold without causing the inner side surface 5 of the C member 27 to come into pressure contact. To assemble the formwork 10, the formwork cutout 38 is inserted into the formwork position, and bolts are inserted into the positioning holes 19, 19 of the joint holes 20, 20 of the flanges 10B, 17B and the flanges 10C, 17C. 21 and insert a nut into the bolt 21
Tighten 22 and fix it.

As described above, in the present embodiment, a plurality of cross beams 3, 3, 3 are provided at a lower portion on one side according to the first aspect.
In a mold for manufacturing a PC member 27 provided with a pretension in the longitudinal direction, a mold cutting portion 38 is cut out from the mold 10 so that the inner plate 18 at the cross beam portion of the mold 10 is According to the third aspect of the present invention, the joining flanges 17B, 10B and 10J are provided at the joining portion between the mold cutting portion 38 including the inner plate 18 and the mold 10, respectively. Since the joining flanges 17C and 10C are provided, the joining flange 17C is provided.
B, 10B, 17C and 10C make it easy to join and disassemble the inner plate 18 to the formwork 10.

Further, as an effect of the embodiment, the lower surface portion 11A continuous with the inner side surface 18 is cut obliquely in a plane to form a form cutout portion.
By forming 38 into a tapered shape in which the plane becomes narrower toward the tip, it is possible to easily pull out and insert from the mold 10. In addition, flanges on both sides in the vertical direction
Because 17B and 17C are substantially in the shape of a substantially C-shaped plane, the flange 10
It can be pulled out without sliding resistance with B and 10C, and can be easily positioned at the mold position by inserting and fitting the flanges 17B, 10B, 17C and 10C.

FIG. 7 shows a fourth embodiment of the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted. The illustrated frame cutout 38 is rotatably provided on the bottom plate 15, and the mounting portion 24 is integrally provided on the lower surface of the bottom plate 15, and an arm is provided on the lower surface of the form cutout 38 on the central side in the vertical direction. The base end of the part 25 is provided integrally, and the tip of the arm part 25 is rotatably connected to the mounting part 24 by a vertical pivot 26.

Then, the form cutouts 38 on both sides in the lateral direction are pivoted downward around the pivot 26 to remove them from the formwork position, and to assemble the formwork 10, the formwork cutouts 38 must be lifted up. Then, a bolt 21 is inserted into the joint holes 20 and 20 of the flanges 10A and 17A, and a nut 22 is fastened to the bolt 21 to fix the joint.

As described above, in the present embodiment, according to the second aspect, the mold cutting portion 38 is cut out from the mold 10 and the mold cutting portion 38 is rotatable with respect to the mold 10. By providing, the inner plate 18 is rotatably provided on the mold 10, so that the inner plate 18 is rotated and removed from the form position, and after the mold is removed, the inner plate 18 is rotated in the opposite direction. The inner plate 18 can be removed and returned by a rotating operation without separating the inner plate 18 from the mold 10.
Can be carried out smoothly, and according to the first and third aspects, the same actions and effects as those of the above-described embodiments can be obtained. Further, in this example, the flange portions 17B and 17C It is provided on both sides diagonally, and the form cutout 38 is arranged so that the interval between the tips of the flanges 17B and 17C is widened downward, which is the rotation direction at the time of removal. Are formed so as to form a C-shape with each other, so that when the form cut-out portion 38 rotates downward, the overlapping flange portions 17B and 10B overlap.
Also, the flanges 17C and 10C do not slide, and the position can be smoothly adjusted when returning by turning upward. Further, in this example, since the formwork cutout portion 38 is formed by partially cutting the formwork 10, the formwork cutout portion 38 is light in weight, so that handling is easy.

Further, as an effect of each embodiment, in the form 10 of the PC girder having the plurality of cross beam forming portions 13, 13, 13A, the inner plates 18, 18 of the cross beam forming portions 13, 13 other than the mountain side are removed. Since it is provided as possible, it is not necessary to remove the inner surface of the cross beam forming part 13A on the mountain side, for example, by changing the length of the valley side according to the site with a PC girder etc. constituting the roof such as a shed,
This is suitable for forming PC digits having different lengths.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, the shape and dimensions of a concrete molded product can be appropriately selected, and the number of cross beams may be four or more. Further, in the embodiment, FIG.
The inner plates 18, 18 of the left and right cross beam forming sections were made removable, but the inner plates 1 of the left and right cross beam forming sections were removed.
8, 18A may be made removable, and the inner plates 18A, 18A of the middle and right cross beam forming portions may be made removable. That is, at least another cross beam forming portion may be formed for the cross beam forming portion serving as the fixed forming portion. The inner plate on the side of the fixed molding portion of the portion may be provided so as to be removable. Further, in the detailed description of the present invention, it has been described that the formwork is cut out to form the formwork cutout, but the formwork is formed in advance by removing the formwork cutout, and the formwork cutout is formed. May be formed separately and assembled.

[0028]

According to the first aspect of the present invention, there is provided a mold for manufacturing a PC member having a plurality of cross beams on one side and pretensioning in a longitudinal direction, wherein an inner plate at a cross beam portion of the mold is provided. Is provided so as to be removable from the formwork position, prevents local damage of the cross beam, is excellent in demolding workability, and
An object of the present invention is to provide a pretension type PC member formwork in which the formwork can be easily handled.

According to a second aspect of the present invention, the inner plate is rotatably provided on the formwork to prevent local breakage of the cross beam portion, to have excellent workability in removing the mold, and to improve the workability of the formwork. An object of the present invention is to provide a pretension type PC member formwork that is easy to handle.

According to a third aspect of the present invention, a joining flange portion is provided at a joining portion between the inner plate and the formwork to prevent local breakage of the cross beam portion, and is excellent in demolding workability. It is another object of the present invention to provide a mold for a pretensioning type PC member in which the mold can be easily handled.

[Brief description of the drawings]

FIG. 1 is a sectional view of a mold showing a first embodiment of the present invention.

FIG. 2 is a side view of the mold showing the first embodiment of the present invention.

FIG. 3 is a plan view showing a first embodiment of the present invention.

FIG. 4 is an enlarged side view of a main part of a mold showing a second embodiment of the present invention.

FIG. 5 is a perspective view of a main part of a mold and a cut-out part of the mold, showing a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a cut-out portion of a mold according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a mold showing a fourth embodiment of the present invention.

FIG. 8 is a partially cutaway perspective view of a PC girder.

[Description of Signs] 3 Cross beam part 10 Formwork 18 Inner plate 10A, 10B, 10C, 17A, 17B, 17C Flange part for joining 27 PC member

Continuation of front page (72) Inventor Tsutomu Ishizuka 29-5, Nishi-Hachijo Minami, Obihiro City, Hokkaido Obihiro Concrete Co., Ltd. (56) References JP-A-5-138639 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) B28B ^7/ 00-7/46 B28B 23/00-23/22 E01F 7/04

Claims (3)

(57) [Claims] 1. A mold for manufacturing a PC member having a plurality of cross beams on one side and pretensioning in a longitudinal direction, wherein an inner plate at a cross beam portion of the mold is removed from the position of the mold. A mold frame for a pretensioning type PC member, which is provided as possible. 2. The pretension type PC member according to claim 1, wherein the inner plate is rotatably provided on the mold. 3. The mold for a pretensioning type PC member according to claim 1, wherein a joining flange is provided at a joint between the inner plate and the mold.