JPH0621952Y2 - Anchor head processing structure - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an anchor head processing structure, in particular, a so-called standard type anchor head processing structure in which tension force is not measured or adjusted after anchor construction. Regarding the improvement of.

[Conventional technology]

In general, permanent and temporary anchors are applied for various purposes such as mountain retaining for construction work, landslide prevention, slope stabilization, and reinforcement of various structures.

This type of anchor is one in which both ends of the tension material are anchored to the ground and the structure, respectively, and the tension material in the middle portion is free from extension deformation and prestressed to this. is there.

That is, as shown in FIG.
Is an anchor body 3 embedded and set in the ground 2, and a tension member 5 extended from the anchor body 3 to a structure 4 on the ground.
And an anchor head 6 for fixing the extending end of the tension member 5 to the structure, and the tension member 5 is tensioned and prestressed.

Since the tensile member 5 is thus prestressed, the anchor head 6 must have sufficient strength for the designed anchoring force and not cause any harmful deformation or obstacle.

Generally, the anchor head 6 is composed of three members, a fixing metal fitting 6a, a bearing plate 6b and a pedestal 6c.
It is classified into the so-called standard type, re-tension type and strain relief type.

The above-mentioned FIG. 4 shows a standard type anchor head 6, which is designed in consideration of an increase or decrease in tension within the design range. Therefore, the pulling margin of the tension material 5 extended from the fixing metal fitting 6a is cut, and this is cut into the concrete 7
Since it is buried inside, the tension cannot be measured or adjusted after the anchor is constructed.

The pedestal 6c is not used when the structure 4 is constructed of prestressed concrete.

[Problems to be solved by the device]

By the way, in the standard-type anchor head processing structure 8 as described above, the anchor head 6 is covered with a mold 9 made of wood or a steel plate in the shape of the finding. Concrete 7 was being placed on.

Therefore, there is a problem in that the work of dismantling and removing the formwork 9 is required after the solidification and curing of the concrete 7, which lengthens the construction period and increases the number of work steps. Further, burrs of concrete 7 adhered to the removed formwork 9, and a large amount of adherence was usually unavoidable because it had to be discarded after one use, which was uneconomical.

Furthermore, in order to reuse the removed formwork 9, a cleaning operation for removing burrs from the concrete 7 is required.

Further, since the mold 9 made of wood or steel plate is relatively heavy, there is a problem that it is difficult to process the anchor head 6 on the slope.

In view of the above problems, an object of the present invention is to provide a lightweight and economical treatment structure for an anchor head, which can shorten the construction period without the need to dismantle and remove the formwork.

[Means for Solving the Problems]

According to the treatment structure of the anchor head of the present invention, the both ends of the tension member are fixed to the ground and the structure, respectively, and the tension member in the middle portion is free from extension deformation. In the anchor that gives prestress to this, while surrounding the periphery of the anchor head exposed from the structure with a net frame as a mold of a predetermined shape, concrete is placed inside and around the net frame. This is accomplished by embedding the anchor head with the net frame.

In the above structure, preferably, the mesh frame can be formed of a steel wire mesh, a synthetic resin mesh, or an expanded metal.

[Action]

According to the above configuration, concrete is placed inside the net frame surrounding the periphery of the anchor head and its peripheral surface, and the anchor head is treated by embedding the anchor head together with the net frame in the concrete. As a result, it is not necessary to dismantle and remove the mesh frame as the formwork, the construction period can be shortened, and the work man-hour can be reduced.

Further, since the form is formed of a net frame, the form frame can be made lighter, and particularly when the net frame is made of a synthetic resin net body, the weight can be extremely reduced. Is easy to apply.

Furthermore, by embedding the net frame together with the anchor head, it is possible to have a reinforcing effect to prevent cracking of concrete, so the net frame is effectively used, does not need to be discarded, and does not require cleaning work. So economical.

When the mesh frame is made of steel plate wire mesh or expanded metal, an extremely excellent reinforcing effect is exhibited.

In this way, since the soundness of the concrete is maintained by being reinforced by the mesh frame, rainwater does not enter the concrete, and corrosion of the steel parts constituting the anchor head embedded in the concrete does not occur. It is surely prevented, and the anchor life is extended.

Further, when the net frame is made of a synthetic resin net body, the rust prevention effect can be enhanced.

〔Example〕

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, the structure 10 of the anchor in the natural ground will be described.

As shown in FIG. 1, a tension member 5 made of the PC steel strand or the like is inserted into a hole 11 formed by excavating the natural ground 2. A portion of the distal end portion of the tensile member 5 which serves as the fixing portion A is covered with a bond sheath 12 such as a deformed sheath, and the ground side which constitutes the free length portion B is covered with an unbonded sheath 13 made of synthetic resin.

Then, the grout 14 is injected into the space inside the drilled hole 11 to be cured, and the cement paste 15 or the grout 14 is injected into the bond sheath 12 at the distal end of the tensile member to be cured to form the fixing portion A, Then, the extension side of the tension member 5 is tensioned with a jack or the like to apply prestress.

The anchor head 6 of the anchor thus formed is exposed to the outside from the structure and is made up of three members: a fixing metal fitting 6a, a pressure support plate 6b and a pedestal 6c.

The tension member 5 inserted into the drilled hole 11 extends from the fixing metal member 6a. The tension material 5 thus stretched is subjected to pre-stress and then the pulling margin is cut.

The pedestal 6c is not used when the structure 4 is constructed of prestressed concrete.

In such an anchor head 6, the anchor head processing structure 16 of the present invention is constructed as shown in FIGS. 1 and 2.

The anchor head 6 exposed from the structure 4 is surrounded by a net frame 17 having a predetermined shape.

The mesh frame 17 is formed of a steel plate metal mesh, a mesh body made of synthetic resin, or expanded metal. Therefore,
There is a high degree of freedom in designing the shape of the mesh frame 17, and for example, as shown in FIGS. It can be formed into a shape.

In addition, if necessary, the strip material 1 is provided on the upper edge of the net frame 17.
8 or a guide ruler (not shown) having a U-shaped or U-shaped cross section is provided.

Then, concrete 7 is cast into the inside of the net frame 17 and the peripheral surface thereof. The viscosity of the concrete 7 is determined by the size of the mesh of the mesh frame 17.

In this manner, the anchor head 6 is embedded in the concrete 7 together with the net frame 17 to form the anchor head processing structure 16 of the present invention.

Therefore, the anchor head processing structure 16 of the present invention is applied to the so-called standard type anchor head 6, and is designed in consideration of the fact that the tension force of the tension member 5 increases or decreases within the design range. There is. That is, since the pulling margin of the tension member 5 extended from the fixing metal fitting 6a is cut and the anchor head 6 is embedded in the concrete 7, the tension force is not measured or adjusted after the anchor is constructed.

As described above, in the anchor head processing structure 16 of the present invention, since the anchor head 6 is embedded in the concrete 7 together with the net frame 17 surrounding the anchor head 6, the net frame 17 like the conventional form 9 is used. Since it is not necessary to dismantle and remove, the construction period can be shortened, and the work man-hour can be reduced.

When the net frame 17 is embedded in the concrete 7 together with the anchor head 6, the net frame 17 serves as a reinforcing material for preventing cracking of the concrete 7. Therefore, the net frame 17 is effectively used and it is not necessary to dispose of it or perform cleaning work, which is very economical.

When the mesh frame 17 is made of steel plate wire mesh or expanded metal, an extremely excellent reinforcing effect is exhibited.

The anchor head 6 is thus embedded in the concrete 7 because the fixing metal fitting 6a, the pressure bearing plate 6b, the pedestal 6c and the extending end of the tension member 5 which constitute the anchor head 6 are made of steel. This is because it is easily rusted by rainwater.

As described above, since the soundness of the concrete 7 is maintained by being reinforced by the net frame 17, the concrete 7 is not cracked, rainwater does not enter the concrete 7, and the anchor embedded in the concrete Head 6
Corrosion of the steel parts constituting the is reliably prevented, and as a result, the life of the anchor can be extended.

Although not shown in the present embodiment, the reinforcing effect can be remarkably enhanced by appropriately suspending the reinforcing bars between the frames of the net frame 17 as necessary. When the reinforcing bars are bridged between such frames, the reinforcing bars can be fixed to the mesh frame 17 by utilizing the mesh, so that construction is easier than in the conventional form 9.

Further, since the net frame 17 is adopted, the weight is lighter than that of the conventional form 9, and particularly when the net frame 17 is formed of a net made of synthetic resin, the weight can be extremely reduced. However, the treatment of the anchor head 6 is easy to construct.

When the net frame 17 is formed of a synthetic resin net body, the net frame 17 can have a rust preventive effect.

[Effect of device]

As described above, according to the present invention, it is not necessary to dismantle and remove the formwork, the construction period can be shortened, and a lightweight and economical anchor head treatment structure can be provided.
In addition, by burying the net frame in concrete, the anchor life can be extended, which is an extremely excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic view showing an anchor structure and an anchor head processing structure of the present invention, FIG. 2 is a partially cutaway schematic view of an anchor head processing structure of the present invention, and FIGS. ) (C) is a schematic diagram showing an example of a cross-sectional shape of a net frame adopted in the treatment structure of the anchor head of the present invention. FIG. 4 is a schematic view showing a processing structure of a conventional anchor and an anchor head. 2 ... Ground; 4 ... Structure; 5 ... Tensile material; 6 ... Anchor head; 17 ... Net frame; 7 ... Concrete; 16 ...
… Anchor head processing structure; 18 …… Band material.

Claims (1)

[Scope of utility model registration request] 1. An anchor in which both ends of a tensile member are fixed to a ground and a structure, respectively, and the intermediate tensile member is free from extensional deformation and is prestressed to the structure. The periphery of the anchor head exposed from is surrounded by a net made of steel wire mesh or synthetic resin of a predetermined shape, or a net frame as a mold made of expanded metal, and at the inside and the surrounding surface of the net frame. A treatment structure for an anchor head, which comprises placing concrete and burying the anchor head together with a net frame.