JP2948158B2 - Formwork for making precast concrete slabs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a formwork for producing a precast concrete slab laid on a girder such as a bridge, and more particularly to a step joint formed on an end surface orthogonal to a supporting girder to form a loop joint bar. The present invention relates to a formwork provided with a side frame to be provided.

[0002]

2. Description of the Related Art A precast concrete slab (hereinafter referred to as PCa slab) having a predetermined shape is stretched in a direction perpendicular to a steel girder, and adjacent PCa slabs are connected to form a series of slabs. In this case, a structure as a printing plate that is continuous also in the beam direction is required so that the individual PCa slabs do not exhibit independent behavior. For this reason, conventionally, PC
The joint structure by the so-called vertical fastening method, which inserts steel and introduces stress by post tension to integrate the floor slab, has been adopted, but in recent years, the loop joint reinforcement is filled with cast-in-place concrete to transmit shear force. In addition, a system that integrates the floor slab is adopted.

In this joint structure, as shown in FIG. 14, a step portion 103 is formed on an end surface of a PCa floor slab 102 disposed on a support girder 101, and upper and lower power distribution reinforcing bars of the floor slab are connected to form a tip. A loop joint bar 104 formed in a loop shape is protruded from the opposing step portion side surface 103a, and the joint portion 105 formed by the opposing step portion side surface 103a and lower thin plate portion 103b is filled with cast-in-place concrete. This is a structure in which adjacent PCa floor slabs 102 are integrally connected.

In order to reduce the load on the floor slab, PCa slab 1
No. 02 generally has a shape in which the plate thickness at the upper part of the support girder 101 is thick, and the plate thickness at the support portion and the cantilever portion is thin, and the pretension type PC steel material 10 is provided in the plate in a direction perpendicular to the girder.
6 are arranged.

In order to manufacture a large number of PCa floor slabs 102 having such a predetermined shape at a factory, a mold is mainly made of steel, and a side frame forming a step portion 103 is formed on a bottom frame in consideration of workability. It was rotatably supported via a hinge member. In addition, a wooden frame that can be easily removed has been used on the surface from which the loop joint bar 104 protrudes, so that the frame can be removed.
In addition, in order to efficiently perform the work of tensioning the PC steel material 106 by the pretension method, a plurality of such formwork are arranged in series, the PC steel material 106 is inserted, concrete is applied, tension is applied, and concrete is hardened. By releasing the tension later, a plurality of PCa floor slabs 102 were simultaneously subjected to prestress.

[0006]

However, since the lower portion of the side frame is bent to cover the thin plate portion 103b, the conventional frame does not allow the side frame to be rotated by the hinge member.
The upper surface of the thin plate portion 103b and the bent portion of the side frame come into sliding contact with each other at the time of rotation, and it is difficult to smoothly remove the frame if concrete is biting into the face plate, and the fore end of the thin plate may be damaged if the forcible rotation is performed. Was.

Further, since the wooden holding form cannot be diverted, it cannot be said to be efficient in terms of both work and cost. In addition, because of lack of flexibility, concrete does not adhere to the reinforcing steel, and concrete leaks from the gap, and steel Inconveniences such as flowing into the mold frame have occurred. Further, since the wooden frame is easily cut into the concrete, if the wooden frame is forcibly removed at the time of removing the frame, the floor slab and the steel form may be damaged.

[0008] The present invention solves the above-mentioned problems, and enables the side frame to be smoothly removed from the frame without causing any damage to the end of the floor slab.
An object of the present invention is to provide a mold for producing a Ca floor slab. It is another object of the present invention to provide a formwork for producing a PCa floor slab, in which a face plate projecting from a loop joint bar can be diverted, which is advantageous in terms of work surface and cost, and which causes less leakage of concrete.

[0009]

In order to solve the above-mentioned problems, a formwork for producing a precast concrete floor slab according to the present invention produces a floor slab having a thicker plate at an upper portion of a support girder and a thinner plate at a span portion. A bottom frame and a side frame for forming a stepped portion on an end face orthogonal to the support girder and projecting a loop joint bar, and a precast concrete floor slab forming mold in which a pretensioning PC steel material is arranged, A side frame, a rib member protruding from the face plate to form a hole, and a hinge member for supporting the side frame so as to be rotatable and supporting the side frame to be able to move laterally;
A locking plate that is provided with a wedge hole that partially overlaps the hole and protrudes from the side of the bottom frame, and by selecting the insertion position of the hole that overlaps with the locking plate, tightening or tightening the side frame It has a wedge for releasing. It is preferable that a rubber plate is attached to the side frame projecting portion of the side frame, and a pair of steel material projecting holes connected to the rubber plate by a vertical slit are formed.

[0010] The side frame has a step portion side surface from which the loop joint bar can protrude, and a face plate which is bent from the side to reach the bottom frame while covering the lower thin plate portion. A plurality of ribs protrude from the outside of the face plate, and a hinge member pivotally supported on the side of the bottom frame supports the side frame. The hinge member is supported by being inserted into the elongated hole so that the hinge member can rotate and also move laterally.

The rib is connected to a locking plate projecting from the side of the bottom frame by a wedge. The hole of the rib material is provided with a locking plate so that the side frame can be tightened or released at the wedge insertion position. While the wedge hole partially overlaps with the wedge hole, an opening for wedge driving is also formed at the tip of the locking plate. With such a configuration, when the wedge is driven into the wedge hole, the wedge to be locked by the locking plate presses the side frame inward. The stop plate and the rib material move in a direction in which they are separated.

Therefore, when a wedge is driven into the opening at the tip of the locking plate during the removal of the frame, the side frame moves in parallel to eliminate the bite between the face plate and the concrete and is separated from the concrete surface.
Thereafter, when the side frame is rotated, there is no sliding contact between the upper surface of the thin plate portion and the bent portion of the side frame, so that the frame can be smoothly removed, and there is no possibility that the leading end of the thin plate is damaged.

[0013] The rubber plate to be attached to the protruding portion of the loop joint reinforcing bar must have a deformability so that the loop joint bar can pass through the vertical slit while being in close contact with the reinforcing bar, and also have elasticity so as not to leak from the vertical slit. . When such a rubber plate is used, familiarity with concrete is improved, and filling can be sufficiently performed. In addition, since the rubber plate is deformed and the adhesion to concrete is refused at the time of demolding, the demolding can be performed smoothly, and the mold and PCa products are not damaged.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view of a mold for manufacturing a PCa floor slab, FIG. 2 is a front view thereof, and FIG.
FIG. 2 is a sectional view showing an II section. This formwork 1 includes a bottom frame 2 and
It has a side frame 3 disposed on both sides in the longitudinal direction and an end plate 4 placed near both ends of the bottom frame 2.
The upper and lower portions of the support girder are formed with irregularities so that the plate thickness h1 is large and the plate thicknesses h2 and h3 of the supporting portion and the cantilever portion are small. The upper bottom frame 2b having the uneven surface is horizontally supported by the base frame 2c. The side frame 3 is provided with a plurality of ribs 5 protruding at appropriate intervals on the outside to hold the face plate 3a, and hinge members 6 pivotally supported on the sides of the bottom frame 2 are supported at predetermined intervals.

The details of the side frame 3 will be described with reference to FIGS. FIG. 4 is a partially enlarged front view of the side frame, and FIGS. 5 and 6.
5 is a sectional view showing a VV section and a VI-VI section of FIG. 4, respectively. The side frame 3 has a step portion 103 formed on an end face orthogonal to the support girder of the PCa floor slab 102, so that the upper portion of the face plate 3a is located inward and is bent outward when approaching the bottom frame 2 to form a thin plate portion. The structure covering 103b is taken.

The face plate 3a is formed to have the same cross section over the entire side frame 3, and the ribs 5 holding the same have substantially the same shape. For this reason, the lower part of the rib 5 for holding the place where the plate thickness of the PCa floor slab 102 shown in FIG. 5 is thinner is located on the side of the bottom frame 2, but the rib 5 where the plate thickness is thicker as shown in FIG. Is substantially the same height as the face plate 2 a of the bottom frame 2.

The hinge member 6 supporting the side frame 3 has a structure in which a pin 6c connects an arm 6a fixed to the lower end of the side frame and a support plate 6b projecting from the side surface of the base frame 2c.
The side frame 3 is rotatably supported with respect to the bottom frame 2 by a long hole 6d drilled in b, and is also supported to be able to move laterally.

A hole 7 is formed below the rib 5 where the plate is thin.
Is formed, and the face plate 3a side of the hole 7 overlaps with the wedge hole 8a of the locking plate 8 projecting from the side of the bottom frame 2. Reinforcing plates 7a and 7b for pressing the wedge 9 are fixedly provided on the face plate side and the outer end of the hole 7, respectively, and a second wedge hole 7c is also formed between the tip 8b of the locking plate 8 and the reinforcing plate 7b. I do. On the other hand, a plate material 10 having a T-shaped section is formed below the rib 5 where the plate thickness is thick, and a locking plate 11 protrudes from the side of the hole 10a and the base frame 2c. The wedge 9 is inserted into the wedge hole 11a to connect the two.

The face plate 3a of the side frame 3 is provided with an opening at the projecting portion of the loop joint bar 104, and a rubber plate 12 is attached thereto. A pair of steel material projecting holes connected to the rubber plate 12 by a vertical slit 12a. The part 12b is formed. Rubber plate 12
When projecting the loop joint bar 104, the vertical slit 1
It is necessary to have a deformability capable of passing through the concrete 2a and elasticity so that the cast concrete does not leak from the vertical slit 12a.

The operation when the side frame 3 is removed from the frame will be described with reference to FIGS. FIG. 7 and FIG.
9 and FIG. 10 are cross-sectional views of the section shown in FIG. 6 during horizontal movement or rotation, respectively. When the wedge 9 is driven into the wedge holes 8a, 11a of the locking plates 8, 11 as shown in FIGS. 5 and 6, the restrained wedge 9 presses the reinforcing plate 7a or the plate 10 inward, so that the side frame is formed. 3 is fastened.

When removing the frame, both wedges 9 are removed, and then the wedges 9 are driven into the second wedge holes 7c as shown in FIG. The wedge 9 acts to increase the distance between the reinforcing plate 7b and the tip 8b of the locking plate 8, so that the side frame 3 eliminates the bite of the concrete and moves in parallel in the direction of the arrow, and the face plate 3a is separated from the concrete surface. . At this time, the pin 6 of the hinge member 6
c also moves sideways in the long hole 6d. Further, the side frame 3 at the place where the plate thickness is thick also moves sideways at the same time as shown in FIG.
Thereafter, when the side frame 3 is rotated about the pin 6c, the upper surface of the thin plate portion 103b and the bent portion of the face plate 3a are separated without sliding contact with each other, so that the frame can be smoothly removed, and as shown in FIGS. The frame is completed.

Next, the structure and operation of the bottom frame 2 will be described with reference to FIGS.
3 will be described. FIG. 11 is a transverse sectional view of the mold 1, and FIGS. 12 and 13 are longitudinal sectional views when a plurality of PCa slabs are prestressed. The bottom frame 2 includes an upper bottom frame 2b and a base frame 2c that slidably supports the upper bottom frame 2b. Therefore, a plate-like slide member 2d is provided on the upper surface of the base frame 2c.
, And a bottom frame sliding guide 2e is attached to a side portion.

In order to efficiently perform the tensioning operation by the pretensioning method, as shown in FIG. 12, a plurality of molds 1 are arranged in series, a PC steel material 106 is inserted, and jacks 108 are inserted through anchors 107 installed at both ends. After fixing and applying a tension, concrete is poured to manufacture the PCa floor slab 102. After the concrete is hardened, the tension is released as shown in FIG.
Since the C steel material 106 contracts, a force acts on the PCa floor slab 102 in a direction to make the adjacent space closer. At this time PCa
The upper bottom frame 2b, which forms the irregularities on the lower surface of the floor slab 102, slides on the upper surface of the base frame 2c, so that the PC steel material 106 can smoothly release the tension.

[0024]

As described above, the PCa according to the present invention is used.
The mold for floor slab production includes a hinge member that rotatably supports the side frame and also supports the side frame so that the side frame can be moved, and a wedge that tightens or releases the side frame by selecting an insertion position. When the frame is removed, a wedge is driven into the side frame to move the side frame in parallel to separate the face plate from the concrete surface. Since the side frame is rotated after the parallel movement in this manner, sliding contact between the upper surface of the thin plate portion of the floor slab and the side frame is eliminated, and smooth frame removal is possible. This eliminates the risk of damage to the thin plate tip.

In addition, since the rubber plate having the vertical slit through which the loop joint can pass is attached to the form according to the second aspect, the face plate can be diverted, which is advantageous in terms of work and cost. In addition, the leakage of the concrete is reduced by the elasticity of the rubber plate which is in close contact with the reinforcing bar, and the familiarity is improved, so that the filling can be sufficiently performed. In addition, since the rubber plate is deformed and the adhesion to concrete is refused at the time of demolding, the demolding can be performed smoothly, and the mold and PCa products are not damaged.

[Brief description of the drawings]

FIG. 1 is a plan view of a mold frame for producing a PCa floor slab.

FIG. 2 is a front view of a mold frame for producing a PCa floor slab.

FIG. 3 is a sectional view showing a section taken along line III-III of FIG. 1;

FIG. 4 is a partially enlarged front view of a side frame.

FIG. 5 is a sectional view showing a VV section of FIG. 4;

FIG. 6 is a sectional view showing a section taken along line VI-VI of FIG. 4;

FIG. 7 is a cross-sectional view showing the cross section shown in FIG. 5 during horizontal movement.

FIG. 8 is a cross-sectional view showing a state in which the cross section shown in FIG. 5 is rotated.

FIG. 9 is a cross-sectional view showing the cross section shown in FIG. 6 during horizontal movement.

FIG. 10 is a cross-sectional view showing a state in which the cross section shown in FIG. 6 is rotated.

FIG. 11 is a cross-sectional view of a formwork for producing a PCa floor slab.

FIG. 12 is a longitudinal sectional view at the time of tension when prestress is applied to a plurality of PCa floor slabs.

FIG. 13 is a vertical cross-sectional view of FIG. 12 when the tension is released.

FIG. 14 is a perspective view of a PCa floor slab placed on a support girder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Form frame 2 Bottom frame 3 Side frame 3a Face plate 5 Rib 6 Hinge member 6c Pin 6d Long hole 7 Hole 7c Second wedge hole 8 Locking plate 8a Wedge hole 9 Wedge 102 PCa floor slab

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B28B 23/00

Claims (2)

(57) [Claims] 1. A bottom frame for producing a floor slab having a large plate thickness at an upper portion of a support girder and a thin plate thickness at a support portion, and a side at which a step portion is formed on an end surface orthogonal to the support girder to project a loop joint bar. In a mold frame for preparing a precast concrete floor slab having a frame and disposing a pretensioning type PC steel material, the side frame is a rib material projecting from a face plate to form a hole, and the side frame is rotated. A hinge member that supports and allows lateral movement, a wedge hole that partially overlaps with the hole, and a locking plate that projects from the side of the bottom frame; A wedge for tightening or releasing a side frame by selecting an insertion position of a hole to be formed. 2. The side frame according to claim 1, wherein a rubber plate is attached to the loop joint bar projecting portion, and a pair of steel material projecting holes connected with a vertical slit are formed in the rubber plate. A formwork for making the precast concrete slabs described.