JPH0416851Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial application>> This invention is a preform for repair work that, after repairing and restoring a cylindrical concrete structure, binds the structure with tendons to further strengthen structural weaknesses. This invention relates to a tension material placement jig for stress.

<Prior Art> Conventionally, prestressed concrete has been used in pressure vessels, water storage tanks, and the like.

However, there has been no repair method for existing reinforced concrete structures such as tanks of this type, which involves repairing cracks and waterproofing layers and then applying post-tension prestress to prevent the structure from cracking again.

When introducing prestress into an existing structure,
Prestressed concrete steel wire (hereinafter referred to as PC steel wire)
When tightly wound around the outer circumferential surface of the peripheral wall, the arrangement must be relatively accurate in order to obtain uniform prestress.

This also applies to the construction of new structures using the pretension method.

Therefore, in order to position the PC steel wire, it has been considered to fix and hold it with anchor bolts driven into the wall.

<<Problems to be solved by the invention>> However, it is desirable to avoid damaging the walls of existing concrete structures as much as possible, and driving anchor bolts is not preferable from the viewpoint of maintaining strength. In addition, positioning the PC steel wire using anchor bolts was a problem that we really wanted to avoid, as it spoiled the appearance and complicated the work.

The present invention was developed in view of the above circumstances, and its purpose is to prevent tension materials such as prestressed steel wires from becoming slack in the middle when placing them on the outer peripheral wall, and to prevent the tension materials from becoming loose in the middle. To provide a prestressing tendon arrangement jig in which the interval between the two falls within a predetermined dimension and uniform prestressing can be introduced efficiently.

《Means for solving the problem》 In order to achieve the above purpose, in this invention, after repairing an existing cylindrical concrete structure, tension material is wrapped around the outer circumference of the structure and tightened, thereby compressing the structure. It is used for repairing cylindrical concrete structures that apply force, and has comb-shaped teeth arranged at intervals corresponding to the winding intervals of tendons wound around the outer circumference of the concrete structure. be.

《Operation》 Comb-shaped jigs are placed on the outside of the surrounding wall at appropriate intervals,
A tendon is passed between the teeth, and the position of the tendon is determined by the sides of the teeth. Since it is comb-shaped, it is easy to wind and arrange the tendons in parallel.

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

Figure 1 shows prestress tension material placement jig 1.
and how it is used.

After the cracks in the cylindrical concrete outer wall 2 are repaired, tension material arrangement jigs 1-1 are installed around the outer periphery at such intervals that the middle part of the unbonded cable does not loosen.

The tendon arrangement jig 1 is provided with teeth 4 in which round steel is welded and arranged in a comb shape at required intervals on the plate surface of a rectangular steel plate 3. Pass the unbond cable 5 between the teeth 4-4 and temporarily tension it. Next, another unbonded cable 5a is wound around the adjacent tooth 4a or the next adjacent tooth 4b, etc., with a separation dimension that matches the desired prestress, and in the same way, other unbonded cables 5b, 5c, 5d are sequentially wound. Wind the
It makes me feel nervous.

The unbonded cable is temporarily tensioned, and once the slack is removed, the tensioning material arrangement jig 1-1 can be removed.

By the way, as for the means for installing the tendon placement jig 1, as shown in FIG.
Since these are used when repairing structures, the work scaffolding is used without removing it.
That is, the reference numeral 6 in the figure is a steel pipe scaffold. A clamping fitting 9 is provided on the steel pipe scaffold 6 at the end of the steel pipe 8, which is attached to the concrete outer wall 2 in the radial direction from near the outer peripheral surface of the concrete outer wall 2 using a scaffold clamp 7. This clamping fitting 9 supports and screws a bolt 10 facing a receiving plate (not shown),
The object between the tip of the bolt 10 and the receiving plate is clamped. The tension material placement jig 1 is
The back side of the steel plate 3 is clamped and fixed to the clamping fittings 9 with bolts 10.

When the temporary tensioning of the unbonded cables 5 is completed in this way, the tensioning material placement jig 1 is removed and replaced above it (see FIG. 3).

As described above, it is not necessary to drive anchor bolts into the concrete outer wall 2 at all. The tensile material arrangement jig 1 is installed using the support frame of the scaffolding used when repairing the outer wall 2, thereby preventing the winding interval of the unbonded cable 5 and the positional deviation due to slack in the middle part thereof. There is. Therefore, prestress can be uniformly introduced by each unbonded cable 5.

<<Effects>> As described in detail above, the prestressing tendon arrangement jig according to the present invention has comb-like teeth, so the winding interval of the tendon can be easily selected, The distribution of compressive force on the outer wall of the structure due to prestress can be uniformly and easily selected.

Furthermore, since no anchor bolts are used, the strength of the outer wall of the structure is not affected, the appearance is not impaired, and bolt holes are not filled.

In particular, if a plurality of arranging jigs are installed in the winding direction of the tendon, looseness in the middle of the tendon can be temporarily caught by the teeth of the jig, thereby significantly improving work efficiency.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the state of use, FIG. 2 is a perspective view showing the means for installing the tendon arrangement jig, and FIG. 3 is a schematic side view showing how the jig is replaced. 1... Tensor arrangement jig, 2... Concrete outer wall, 3... Steel plate, 4... Teeth, 5... Unbonded cable, 6... Steel pipe scaffolding, 7... Scaffolding clamp, 8... Steel pipe, 9 ... Clamping fittings, 10 ... bolts.

Claims (1)

[Scope of utility model registration request] After repairing an existing cylindrical concrete structure, tension material is wrapped around the outer periphery of the cylindrical concrete structure and tightened, thereby imparting compressive force to the structure. 1. A tendon arrangement jig for prestressing, characterized in that the jig is provided with comb-shaped teeth arranged at intervals corresponding to the winding intervals of the tendon wound around the outer peripheral surface of a concrete structure.