JPH01207553A - Fixing tool for unbond pc steel stand - Google Patents

Abstract

PURPOSE:To facilitate execution of works for a concrete structure by providing a plurality of tapered holes in the base construction, fixing a plurality of unbond PC steel strands, and by approaching the divergent point of the unbond PC steel strands. CONSTITUTION:A plurality of tapered holes 2 for pressure fitting of a fixation wedge after strand tightening through steel strand 11a of unbond PC steel strands 11 are provided independently in one body construction. Provision of these tapered openings 2 in the body 1 of a fixation tool to be embedded in concrete permits fixation of PC steel strands 11 in the same number as the number of tapered holes directly by the use of wedge in the body 1 as a pressure bearing member, and also the span between the tapered holes can be lessened remarkably.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides a PC steel stranded wire for unbonded construction method (hereinafter simply referred to as unbonded PCI stranded wire) which is buried in concrete and applies compressive force to the concrete member. ) relates to a fixing device that holds the ends of

[Conventional technology]

In recent years, beams and floor slabs of architectural structures have been developed using the boss tension method using unbonded PC steel strands that do not require grouting work and have a relatively small cross-sectional loss rate of reinforced members.
Alternatively, construction methods that apply prestress to concrete members such as tanks to control deflection and cracking have become widespread.

In this method, both ends of the prestressed steel strands after tensioning are anchored to fixing devices buried at both ends of the concrete member. At that time, each prestressed steel stranded wire is fixed individually as an anchor. A cast metal fixture for the wire ring is often used for the unbonded pciIi1 structure. There are 20 in Figure 4.

In addition, ■ 111 from multiple unbonded PC steels in the fixing part.
In this case, the fixing device shown in FIG.
Either by using an anchoring device 30 consisting of an element or by press-fitting a sleeve with a tapered hole into the outer circumference of each PC steel strand.
A method is adopted in which the pieces are fixed one by one and each piece is supported by a single bearing plate using a fixing device having a structure similar to the one shown in FIG.

[Problem to be solved by the invention]

When applying large prestress to concrete members,
It is common to place unbonded PC steel strands within a member at narrow intervals, one by one. However, such an arrangement
When attempting to form an opening in the concrete member at a later date, handling of the tensed PC steel strands becomes a problem.

Therefore, in the future, in order to avoid such wires and open as large an opening as possible, multiple unbonded PC steel stranded wires (often two) may be bundled together to widen the arrangement pitch.

However, if the fixing device shown in Fig. 4 is used in such a case, the bundled unbonded PC steel strand wires 11 need to be branched far before the fixing device as shown in the figure.
This results in deterioration of work efficiency and increase in construction costs, making it impossible to fully meet the demands for construction of building structures.

On the other hand, although the anchoring device shown in Fig. 5 or a similar anchoring device can bring the branch points of the bundled wires closer together, it is expensive in itself, and the anchor head etc. are independent from the bearing plate. There were also problems with construction.

Therefore, an object of the present invention is to provide a fixing device that eliminates these problems and improves the workability and economic efficiency of prestressed concrete structures using unbonded PC steel strands.

[Means to solve the problem]

The fixing tool of the present invention is characterized in that a plurality of taper opening holes are provided in one main body independently of each other, into which the fixing material is press-fitted after the wire is tensioned through the unpond PC@stranded steel wire. have

In addition, if the main body is provided with an engaging part of a support member that connects the main body to the concrete formwork in a state where the pocket former can be held between them, the construction workability of the structure will be further improved. Become.

[Effect]

By providing a plurality of tapered holes in the main body of the fixing device to be buried in concrete, it is possible to directly fix the same number of PCI stranded wires as the number of taper holes using a pattern on the main body, which serves as a bearing pressure body. The distance between the holes can also be made sufficiently smaller compared to the construction method shown in FIG.

〔Example〕

An embodiment of the present invention will be explained based on FIGS. 1 to 3.

In the figure, 1 is the main body of the fixing tool made of cast metal, 2 is a plurality of tapered holes (two in the figure) provided through the main body, and 3 is
．． Reference numerals 4 denote bearing flanges protruding from the front and rear parts of the main body in order to engage the concrete 12, and 5 refer to flanges of the main body 1 corresponding to each hole in order to facilitate the insertion of cotton from the rope into the holes 2. A stranded steel wire insertion guide is provided on the back side concentrically with the hole 2, and 6 is a reinforcing rib provided between the flanges 3 and 4.

Further, reference numeral 7 denotes a notch provided on both outer edges of the front bearing pressure flange 3, and a bolt, which will be described later, is locked in this notch.

An exemplary fixing tool 10 is obtained by combining the main body 1 configured as described above with a shutter 8 shown in FIG. 3 having a structure in which a tapered cone is vertically divided into a plurality of pieces.

Next, how to use this fixing device will be explained with reference to FIG.

First, the bolts 13 are fitted into the notches 7 at both ends of the flange 3 and engaged, and a pocket former 1 made of plastic or rubber is inserted between the main body 1 and the concrete formwork 14.
5, and the other end of the bolt 13 is inserted into the formwork 14 and tightened from the outside of the formwork. As a result, 1 and 15 are firmly fixed to the formwork 14.

Next, the two unbonded PC steel stranded wires 11, which are bundled together, are branched slightly before the main body 1, and the end side of the polyethylene sheath 11b of each stranded wire is cut off from the guide 5 and exposed. The stranded steel wire 11a that has become stranded is guided by the guide 5 and passed through the hole 2. Next, concrete 12 is poured into the formwork, and after curing and hardening, the mold 14 and pocket former 15 are removed in this order.

After that, pattern 8 along the steel wire into the opened taper hole.
After setting the wire and driving it in lightly, set the special tension jack and tension the steel strands one by one until they are completely fixed.

The holes 2 are preferably provided at appropriate intervals so as not to interfere with tensioning and fixing work, and the number of holes to be provided is preferably 2, or at most 3. This is because if a large load is applied to one anchor, the integrity of the concrete around the anchor will be affected.

(Effects) As described above, the fixing tool of the present invention is capable of fixing a plurality of unbonded PC steel stranded wires by providing a plurality of taber opening holes in one main body. The workability of concrete structures can be improved by bringing the branch points of the steel strands closer together.

In addition, compared to the construction method shown in Figure 4, the number of fixing devices used is small, and on the other hand, compared to the construction method shown in Figure 5, the structure is simpler and easier to handle. Work efficiency also improves.

Furthermore, the construction employing the second aspect of the present invention has excellent workability in attaching the main body and pocket former to the formwork and removing the pocket former, and can contribute to further popularization of the unbonding method.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a front view of an example of the fixing device (main body only) of the present invention, FIG. 3 is a cross-sectional view of the fixing device in use, and FIG. 4 and FIG. 5 are of a conventional fixing device. Unpond PC used
It is a diagram showing the fixing state of the stranded wire. 1... Main body, 2... Tapered opening hole, 3.4... Flange for bearing pressure, 5... Insertion guide, 6...・Reinforcement lip, 7...Notch, 10...
・Fixing tool. Patent applicant: Sumitomo Electric Industries, Ltd. Agent: Kama 1) Text 2 Figure 1 Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) An unbonded PC steel stranded wire in which a plurality of taper opening holes into which the fixing wedge is press-fitted after the steel stranded wire is tensioned are installed independently in the main body of the fixing device, which is used by being buried in concrete. Fixture. (2) The unbonded PC steel according to claim 1, wherein the fixing device main body is provided with an engaging portion of a support member that connects the main body to the concrete formwork in a state in which the pocket former can be held between them. Stranded wire anchor.