JPH0573566B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is directed to forming prestressed concrete (hereinafter referred to as PC) slabs mainly used as pavement slabs by intersecting sheaths for inserting prestressed concrete steel materials vertically and horizontally. The present invention relates to a sheath spacer that can be used to fasten sheaths in PC plate manufacturing, for fastening sheaths at intersecting positions and at the same time positioning the sheaths at a predetermined covering height from the bottom of the PC plate.

(Prior Art) In recent years, paving using a PC version has become popular for airport runways, taxiways, and even general roads.

When molding the PC plate used for this type of pavement,
In the case of casting on site, for example, as shown in Figures 5 and 6, a base course paper 2 is laid on the surface of a roadbed 1, reinforcing bars 3 are arranged in a lattice pattern on top of it, and then prestressing steel material is inserted on top of it. The sheaths 4 and 5 are arranged in a grid pattern. The positioning of each sheath is determined by connecting the upper and lower sheaths 4 and 5 to each other with a binding wire 6 at the intersection point, and using a spacer made of a concrete piece between the roadbed paper 2 and the lower sheath 5. This is done by intervening 7.

After completing the placement of the reinforcing bars 3 and sheaths 4 and 5 in this way, concrete is poured to form a paving slab, and then the PC steel material is inserted into the sheaths 4 and 5.
By tensioning this, stress is introduced and the PC
It is a paved version.

In addition, when molding the precast PC version,
A formwork is used in place of the roadbed described above, and the other steps are the same as those described above.

(Problems to be Solved by the Invention) The conventional method described above uses a spacer made of concrete pieces and a binding wire for positioning the sheath. It takes a lot of work to tie the sheath, and it has to be done without stepping on the sheath, so the worker is forced to work half-heartedly, creating harsh working conditions and increasing inefficiency. It was spot on. Further, since the spacer is simply placed under the sheath, it is likely to shift during sheath positioning work or concrete pouring work, and in some cases, there are problems such as deviations in the buried height of the sheath.

In view of such conventional problems, the present invention aims to provide a sheath spacer that can be used to fasten sheaths and determine the covering height at the same time in the production of prestressed concrete slabs with a single touch. be.

(Means for Solving the Problems) The gist of the present invention is to solve the above-mentioned conventional problems and achieve the intended purpose.
A substantially inverted U-shaped upper sheath that straddles the upper outer periphery of the upper sheath at the intersection of two sheaths that are arranged horizontally above and below and intersect with each other, with both ends hanging down from the sides of the lower sheath. The fitting part and the lower ends of the U-shaped both parallel pieces are respectively connected to a pair of lower sheath fitting parts curved in an arc shape along the outer periphery of the lower surface of the lower sheath, and both lower sheath fitting parts. The present invention relates to a sheath spacer and a sheath spacer for fastening between sheaths in the production of prestressed concrete slabs, which integrally has a pair of supporting legs.

(Function) The inter-sheath fastening spacer of the present invention has the upper sheath fitting part straddle the upper sheath at the intersection position of the sheaths that are orthogonal to each other, and the both lower sheath fitting parts facing downward with the top part as the center. By rotating it under the sheath, the two sheaths are fastened together. At this time, the support legs are oriented vertically and suspended below the sheath, and both sheaths are positioned at a predetermined height by bringing their lower ends into contact with the roadbed or template surface.

(Example) Next, an example of implementation of the present invention will be described with reference to FIGS. 1 to 4.

This sheath spacer, which also serves as a fastener between sheaths, is made by bending a single wire rod and molding the whole piece into one piece.
It has an upper sheath insertion part 11 having a substantially inverted U shape at the top, and both parallel pieces 11a, 11a of the inverted U shape.
It has a pair of lower sheath fitting parts 12, 12 whose lower ends are respectively curved in the same direction and formed into an arc shape, and further, the respective tip sides of both lower sheath fitting parts 12, 12 are bent downward. support leg 13,
It is set at 13. The lower ends of both support legs 13, 13 form horizontal shaft portions 13a, 13a bent at a substantially right angle toward the lower sheath insertion portion. The support leg portion 13 including the horizontal shaft portions 13a, 13a,
An anti-rust coating 14 made of synthetic resin paint is applied to the outer circumferential surface of approximately the lower half of the housing 13 .

In addition, this spacer is connected to the upper sheath insertion part 1.
1 and the bottom upper surface position of the lower sheath fitting part 12.
The length is equal to or slightly shorter than the sum of the outer diameters of 5.

When using this spacer, please refer to Figures 1 and 4.
As shown in the figure, by fitting the upper sheath into the upper sheath fitting part 11 and fitting the lower sheath 5 into the lower sheath fitting parts 12, 12 at the intersection position of both sheaths 4 and 5, Both sheaths 4, 5 are elastically fastened in an orthogonal arrangement and horizontally positioned. And the support leg part 13,
In the case of on-site casting, place the lower end of 13 on the roadbed paper 2,
Further, in the case of precast plate production, both sheaths 4 and 5 are positioned at a constant covering height by being supported on a bottom template.

In addition, to install this spacer, the upper sheath fitting part 11 is placed over the upper side of the upper sheath 4 as shown by the dotted lines in FIG. and in this state, rotate the entire lower sheath fitting part 12, 12 about the top 11b of the upper sheath fitting part 11 in a direction to push it under the lower sheath. The distal end side of 11 is pushed down and elastically enters under the lower sheath 5.

(Effects of the Invention) As described above, the sheath spacer used for fastening between sheaths in the production of the PC plate of the present invention has an upper sheath insertion portion that spans over the upper sheath at the intersection position of the sheaths that intersect in the vertical direction in the horizontal direction. By providing a lower sheath insertion part that is integrally formed at both ends of the lower sheath and curved in the direction along the bottom of the lower sheath, fastening of both sheaths can be completed by simply rotating the sheath while straddling the upper sheath. The installation process is simple and quick. Moreover, support legs are provided integrally with the lower sheath insertion part,
When the sheaths are connected, they are fully upright and in contact with the roadbed (or formwork), which makes it possible to always position the sheath at a constant cover height from the roadbed, and the subsequent PC version The spacer no longer comes off during various molding operations.

[Brief explanation of the drawing]

Fig. 1 is a tilted view showing an embodiment of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a side view, Fig. 4 is a sectional view in a state of use, and Fig. 5 is a plan view showing a conventional example. FIG. 6 is a longitudinal sectional view of the same. 11... Upper sheath fitting part, 11a... Parallel piece part, 12... Lower sheath fitting part, 13... Leg part,
13a...Horizontal contact portion, 14...Rust-proof coating.

Claims (1)

[Claims] 1. At the intersection of two sheaths arranged horizontally above and below each other and intersecting each other, the sheath extends along the outer circumference of the upper surface of the upper sheath, and both ends are suspended from the sides of the lower sheath. a substantially inverted U-shaped upper sheath fitting portion; a pair of lower sheath fitting portions in which the lower ends of the U-shaped both parallel pieces are curved in an arc shape along the outer periphery of the lower surface of the lower sheath; A sheath spacer for fastening between sheaths in the production of prestressed concrete slabs, which integrally has a pair of support legs connected to the sheath insertion part. 2. The sheath spacer for fastening between sheaths in the production of prestressed concrete slabs according to claim 1, wherein the upper sheath fitting part, the lower sheath fitting part, and the support leg part are integrally formed by bending a single metal wire. 3. The sheath spacer for fastening between sheaths in the production of prestressed concrete slabs according to claim 2, wherein the outer peripheral surface of the lower end side of the leg portion is coated with a synthetic resin coating material to prevent rust.