JPS6263748A - Anchor jig of prestressed concreie - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a concrete/stressed concrete anchorage, and more particularly to an improved anchorage for significantly increasing durability.

[Prior Art] /1/ Stressed concrete, as is well known, is a concrete product that cannot bear compressive loads.

Insert a wire such as steel through the through hole of a concrete body provided with a through hole, tension the wire, and then connect both ends of the wire to both ends of the concrete body. There is a method of fixing using a fixing tool. There are many types of this fixing device. Figure 1 is a plan view showing an example of the fixing device, and Figure 12 is a plan view of an example of the fixing device.
It is a cross-sectional view along the -■ line. Reference numeral 1 indicates an outer cone, which has a tapered inner hole. Reference numeral 2 designates a truncated cone-shaped inner cone that fits into this inner hole, and has a central hole of equal diameter.

This inner cone 2 is divided into three pieces Q12a.

2b, 2C. The wire rod 3 is inserted into the center hole of the inner cone 2, and the wire rod 3 is pulled out through the wedges 2a, 2b, 2c.
The tightening is prevented by force, and the wire is thereby fixed.

FIG. 3 is a plan view showing the inner cone of the fixing device into which a 7-wood wire rod is inserted and fixed. In this fixing device, the inner cone is divided into six parts, six patterns 4a to 4 are formed, and a groove 5 for inserting a wire is provided on the surface adjacent to each of the two wedges. The wire is inserted through these grooves 5 and the center hole of the inner cone and fixed therein.

In addition, Hochtief, B-eye finger
r, Held u.

Various fixing devices are known, such as Franke, Moraudi, and Nippon Auwens.

As described above, a large number of types of fixing devices are known, but steel is widely used as a material because it requires high strength.

[Problems to be Solved by the Invention] Steel fixing devices have considerable durability under normal use environments, but rust occurs in highly corrosive environments. Along with its own strength reduction,
Due to the occurrence of rust, the deterioration of the surrounding concrete progresses. (For example, when rust occurs, it undergoes volumetric expansion, which can lead to fine racks in the concrete.) Therefore, when using conventional prestressed concrete, for example for offshore structures or structures near the coast, it is difficult to compare The problem is that the prestress is likely to decrease at an early stage.

As a countermeasure against this problem, the fixing member and the fixing member are sometimes made of stainless steel, and a corresponding improvement in durability has been achieved, but the corrosion resistance under strong environments such as salt damage is still insufficient.

[Means and effects for solving the problems] The presto concrete fixing device of the present invention has a ceramic coating applied to its surface to improve the corrosion resistance of the fixing device,
This greatly improves its durability.

The present invention will be explained in more detail below.

The ceramic used for the coating in the present invention may be oxide-based, nitride-based, or carbide-based, but according to the studies conducted by the present inventors, nitride-based and carbide-based ceramics are preferred. It was recognized that the corrosion resistance was superior to that of oxide-based materials. Among nitrides and carbides, Ti-based TiN and T f C were found to be most suitable in terms of adhesion, wear resistance, galvanic corrosion resistance, and the like.

When coating with TfN and TiC, the corrosion resistance improves as the thickness increases.

Practically speaking, it is preferable to set the thickness to 10 μm or less, especially 5 pm or less, because of the increase in coating processing cost or the risk of cracking if the coating becomes too thick.In addition, in the case of TiN and TtC, sufficient corrosion resistance is ensured. For this purpose, a coating thickness of at least 0.5 gm, particularly lpm or more is preferred.

When coating with a ceramic other than TiN or Tic, it is preferable to make the coating thicker than in the case of TiN or TiC due to the lower corrosion resistance.

In the present invention, it is preferable to apply a corrosion-resistant metal coating to the lower layer of the ceramic coating. In other words, the ceramic coating will not cause any problems if carefully coated, but if pinholes occur, salt,
Corrosive components such as various ions may pass through this pinhole and reach the surface of the base material of the fixing tool, causing corrosion of the base material. Even if a pinhole exists in the ceramic coating and a corrosive component passes through, it is possible to prevent further penetration into the interior and prevent base material corrosion even more reliably.

Such corrosion-resistant metals include Ti, Ta, Cr, N1
．． W... etc., but when the ceramic coating is TiN or TiC, it is preferable to use Ti as the corrosion-resistant metal.

The coating thickness of the corrosion-resistant metal is preferably about 0.1 to 10 m, particularly about 0.5 to 3.0 m.

In the present invention, the ceramic or corrosion-resistant metal coating can be easily formed by an ion blasting method commonly referred to as a vapor phase plating method, a sputtering method, or the like. Furthermore, among ion blasting,
I (CD method (hollow cathode discharge method)) is preferably used to achieve a high ionization rate of 20 to 40%.

In addition, the fti of the fixing device to which the coating described in Section 1- is applied is
The material may be any material conventionally used for fixing devices as long as it can be coated.

The present invention relates to a fixing device having the structure shown in one drawing and the above-mentioned Hoc
It can be applied to various types of fixing devices in addition to fixing devices such as htief, B11fir+, and get.

[Example] A T with a thickness of 1.0 x m was applied to the surface of a common steel fixing device having the structure shown in Fig. 1.2 by an ion plating method.
i coating was applied, and further north of it was coated with 2JLrn of TiN.

This fixing device was placed in a 5 wt% salt solution at 35°C for 500 hours.
Although it was immersed in water, no rust occurred.

On the other hand, a stainless steel fixing device that was not coated with the above coating was subjected to the same immersion treatment.

It was observed that the entire surface was oxidized.

[Effects] As described in section 2 below, the fixing device of the present invention is coated with a corrosion-resistant ceramic coating, and has extremely high durability.
Furthermore, by applying a corrosion-resistant metal coating to the F layer of the f:r multi-layer coating, durability is further increased. In addition, it can be manufactured by applying a thin coating to the conventional product, and has good dimensional accuracy.

Therefore, it can be used stably for a long period of time even in highly corrosive environments such as offshore structures and structures installed near the coast.

[Brief explanation of the drawing]

Each of FIGS. 1 to 4 is an explanatory diagram of the structure of the fixing device. 1...Outer cone, 2...Inner cone, 3
···wire. Agent Patent Attorney Tsuyoshi Shigeno Figure 1 Figure 3 Figure 4 d

Claims (2)

[Claims] (1) An anchor for prestressed concrete characterized by having a ceramic coating with corrosion resistance applied to the surface. (2) Claim 1, characterized in that a corrosion-resistant metal coating is applied to the lower layer of the ceramic coating.
Anchors for prestressed concrete as described in Section.