KR20150046680A - Prestressing method using non-composite parts of tendon and concrete structure therewith - Google Patents

Abstract

A method of manufacturing a concrete structure (concrete, PSC beam, and the like) in a pretension means comprises: (a) a step of applying a hardening retardant to only a section of a tendon and forming a non-composite section (A1) in order to maintain a non-composite state with the concrete; (b) a step of placing and curing the concrete so that a prestressed tendon is embedded by including the non-composite section (A1) before the hardening retardant is hardened and allowing the prestress to be introduced to the cured concrete by releasing the prestressed tendon while preventing the prestress from being introduced to the concrete surrounding the tendon of the non-composite section (A1); and (c) a step in which the hardening retardant outside the tendon (A1) is cured in the non-composite section to be integrated and moved with the concrete as the hardening retardant is hardened.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prestress introduction method using a non-synthetic zone of a torsion material, and a concrete structure manufactured using the torsion prestress method. 2. Description of the Related Art [0002]

The present invention relates to a method of introducing a prestress using a non-synthetic section of a tensional material and a concrete structure manufactured using the method. More specifically, it is possible to easily adjust the introduction amount of the prestress by the prestressing method in the case of manufacturing the beam by the pre-tension method, and a method of introducing the prestress using the non-synthesis section of the torsion material manufactured in a more structurally more efficient manner, It is about concrete structures.

A conventional prestressed concrete beam (PSC beam) is generally tensioned by applying a tensile force to a prestressing material (usually a PS strand or a PC strand), and after the concrete is laid and cured, the prestressing material is released by the adhesive force between the prestressing material and the concrete A pre-tension method in which a compressive prestress is introduced into a concrete section,

A post-tensioning method in which a sheath is disposed over the inside of a concrete section, a tension material is inserted into the sheath after curing of the section of the concrete, and the tension is applied to both ends of the PSC beam to introduce a compressive prestress into the end face of the concrete.

At this time, the pre-tension method has the following advantages in comparison with the post-tension method.

First, since the tension is introduced by the adhesive force between the concrete and the tension member, a separate fixing member is not necessary.

Second, it does not require sheathing because PS tensions are tightened in advance.

Third, there is no need for grouting, which is a filling operation of the sheath necessary for the post tension method.

Fourth, there is no need for a fixing part reinforcing bar near the fixing device of the tension member required in the post tension method.

Fifth, it is possible to minimize the abdominal thickness of the PSC beam and the cross-sectional dimension of the concrete of the fusing part compared to the post-tensioning method.

Sixth, members of the same shape and dimension can be manufactured in large quantities. (Long-line method)

That is, in the pre-tensioning method, as shown in FIG. 1A, a single mold 10 is used and a plurality of molds 10 are arranged in series on the bed 20 as shown in FIG. A method of manufacturing a plurality of members by introducing one tension force can be classified into a long-line method. If the long-line method is used, a large number of members can be manufactured at once.

1A and 1B, the single mold method or the long line method or the bed 20 is installed on the floor by the shear key 21 and the reaction force band 40 is separately provided on one side of the bed, The tension member 60 and the fixture 50 are used to line-tighten the tensile member 30, and the concrete is poured and cured in the formwork previously installed in the bed 20 to produce a member. Such a manufacturing method is subjected to the same manufacturing process.

Therefore, despite the many advantages of pre-tensioned PSC beam fabrication, it is not widely used in Korea because the pre-tension system requires extra pretensioning equipment, There is a problem in that it is not easy to easily determine the member end face and the tension of the tension member and the fixing position in response to the member force.

That is, when the PSC beam is manufactured by the post-tensioning method, the bending moment due to the load applied to the PSC beam is largest at the central portion and decreases gradually at the end portion. The bending moment of the PSC beam is arranged in a parabolic shape (Corresponding to the member force) so as to introduce more prestress into the central region, and the concentratedly arranged tension member is pulled out of the lower flange or the abdomen of the PSC beam to be tensioned and fixed And change the settlement position).

That is, the post-tension PSC beam can relatively easily adjust the introduction amount of the prestress introduced by the prestressing material in the manner of adjusting the arrangement position of the prestressing material, the tension and the fixing position,

In the case of the pre-tension method, since the tension is preliminarily tensioned from the bed by using the reaction force band 40, the tension jack 60 and the fixture 50, the concrete is placed and cured to produce the PSC beam. The PSC beam corresponding to the sectional force of the member is inevitably manufactured by the post tension method instead of the pre-tension method.

Accordingly, it is an object of the present invention to provide a pre-stress introduction method using a non-synthetic section of a tensile material capable of introducing a pre-tension corresponding to a member force to a desired site even when a concrete structure is manufactured by a pre- And to provide a concrete structure manufactured using the same.

In order to solve the above problems,

In the pre-tensioning method, since the introduction of the prestress into the concrete structure utilizes the action of introducing the prestress into the concrete by releasing the tensioned prestressing material in advance in a state where the prestressed prestressing material and the concrete placed so as to be embedded with the prestressing material are combined with each other, The amount of pre-tension is adjusted by controlling the synthesis site and time of concrete and tension material. In other words,

A part of the tensional material embedded in the concrete is applied to the delayed curing agent to separate the tensional material and the poured concrete. This is a method to control the synthesis time of the concrete and the tension material. The delayed curing agent applied to the tension material plays a role of preventing the synthesis of the concrete and the tension material at the initial stage of the concrete curing. When the time is elapsed (adjustable) And is synthesized with a tensile material. If the synthesis time is adjusted after the introduction of the prestress, the prestress is not introduced into the region where the retardant is coated.

Specifically, for this purpose,

In the pre-stress introduction method by the pre-tension method,

(a) forming a non-synthesis zone (A1) by applying a curing retardant only to a part of the tensile material to maintain the non-composite state with the concrete;

(b) before the curing retarder is cured

The concrete which is filled with the tensioned material including the non-synthetic section A1 is cured and cured, and the tensed material is released to allow the prestress to be introduced into the cured concrete. In the concrete surrounding the tensioned material of the non-synthetic section A1, ; And

(c) curing the hardening retarder to make the hardening retardant outside the tensile material cure in the non-synthetic section (A1) so that the hardening retardant cures and integrates with the concrete. And a concrete structure manufactured using the same.

According to the present invention, in a concrete structure (for example, a PSC beam) manufactured by a pretension method, more tensile material is disposed at a portion where a large bending moment is generated, and other portions of the tensile material extending through the portion are not combined with concrete By installing or applying a hardening retarder, it is possible to design a member section effectively corresponding to the member force even in a concrete structure manufactured by the pretension method.

Since the delayed curing agent is a material or material that can be easily purchased in a concrete structure manufactured to introduce a prestressing, it is economical and does not require any special technique in its use, and thus has no effect on workability and workability. Lt; / RTI >

FIGS. 1A and 1B are construction drawings of a concrete structure manufactured by the conventional pretension method,
FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating an operation of a prestress introduction method using a non-
FIGS. 3A, 3B, 3C and 3D are flow charts of a method of introducing a prestress using a non-synthesizing section of a tensile material of the present invention,
FIGS. 4A, 4B, 4C, 4D, 4E and 4F are illustrations of a concrete structure manufactured by the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

[Method of introducing the prestress using the non-synthetic section of the taut material of the present invention]

FIGS. 2A and 2B illustrate a conceptual diagram of adjustment of a prestress introduction section by non-synthesis section formation according to the present invention.

In the pre-tension type concrete structure, as described above, the bed 20 is installed on the floor by the shear key 21 and the reaction force band 40 is installed separately on one side of the bed, The tension member 30 is tensioned by using the installed tension jack 60 and the fixture 50 and the concrete is placed and cured in the formwork previously installed in the bed 20 to manufacture the member.

That is, after the tension member 30 is first tensioned and fixed in the manufacturing stand, the concrete is laid so that the tension member 30 is buried. When the inserted concrete is cured, the tension member drawn out of the concrete is released, And the prestress is introduced into the concrete by the elastic restoring force.

Accordingly, the non-synthetic section is formed so that the tensions embedded in the concrete are not combined with the concrete. There are two methods.

First, since the tensile member 30 is, for example, a PC stranded wire, it is a method of installing a sheath 110 (replaceable with a SHEATH or PVC pipe) that surrounds the tensile member 30 in a predetermined section such that a prestress is not introduced.

The sheath 110 is formed in the form of a corrugated pipe and serves as a pipe preventing the PC stranded wire from contacting the concrete laid thereon.

As shown in FIGS. 2A and 2B, the concrete structure 100, which is a PSC beam having an I-shaped cross-section, is shown in a front view and a cross-sectional view of the concrete structure 100. The pretensioned bed 20, And the tension jack 60 and the fixture 50 are not shown.

At this time, it can be seen that the tension members 30 are arranged in advance in the upper flange and the lower flange of the PSC beam, but are arranged in a straight line.

In the pre-tension type, the tension members 30 are generally arranged in a straight line, but they may be arranged in a curve or parabolic shape using a device such as a saddle.

At this time, it can be seen that the sheath 110 is laid on the non-synthetic section A1 in the tensile member 30 of the present invention. That is, the sheath 110 is disposed to surround the prestressing material 30 at both ends of the PSC beam, and the prestressed material is not introduced into the PSC beam by the prestressed prestressing material 30, .

As a result, the sheath 110 is not disposed at the central portion A2 excluding both ends of the PSC beam. Therefore, the prestress is introduced by the prestressing material 30, but the prestress is not introduced at both ends, It is possible to control the introduction of the prestress to the desired site.

The PSC beam can be manufactured by filling the grouting material in the sheath and then curing it to complete the prestress and introduce the prestress into the non-synthesis zone A1 and A2.

Next, the hardening retarder 120 is used instead of the sheath 110 as shown in FIGS. 2C and 2D.

When the curing retardant 120 is applied to the tensile material 30, the cured concrete is contacted with the curing retardant and the curing retardant 120 is cured by the curing retardant 120. [ do.

First, in the cured concrete, the prestress is introduced into the concrete in the cured part by releasing the tension material, so that the prestress can be selectively introduced into the desired site.

If the curing retarding action by the curing retarder is stopped after all the prestresses are introduced, it can be understood that the prestress is not introduced in the region where the curing retardant is applied. Also, I will not.

The sheath 110 and the curing retarder 120 have a function of forming the non-synthesis section A1 of the present invention. Since the installation position and the number thereof can be arbitrarily adjusted, Control is possible.

Further, in the non-synthesis section A1, the hardening retardant is applied between the concrete to be poured in the tense tensions (outside), and the concrete paved with the tense material is formed by controlling the synthesis time. After the curing retardant is cured by re-tensioning, the tensional material maintains its straightness to move integrally with the concrete.

That is, if the tension of the tension member is released in the non-synthetic section A1 due to the release of the tension member, if the tension member is held in a taut state, if it can not maintain the straight line state, it may affect the integration with the concrete. Curing.

Of course, even if sheath is used, it does not matter whether the grouting material is hardened by re-tensing before the grouting hardening.

[Method for introducing a prestress using a non-synthetic section of the tensile material 30]

FIGS. 3A, 3B, 3C and 3D illustrate a flow chart of a method of introducing a prestress using a non-synthetic section of a taut material according to the present invention.

First, the bed as shown in FIG. 3A is installed on a floor by a shear key, and a fixing belt 50 is provided on one side of a reaction force band formed at both ends of the bed.

One end of the tension member 30 is fixed to the one reaction force band and the other end passes through the other reaction force band to extend to the fixing belt 50 via the bed and then fixed to the fixing belt.

At this time, a tension jack is installed between the other reaction force band and the fixing belt.

At this time, the hardening retardant 120 is installed / applied to the non-synthetic section A1 of the concrete structure in the tensile member 30. [

Next, as shown in FIG. 3B, a tension jack mounted between the other reaction force band and the fixing belt is actuated to tense the tension member 30.

Next, as shown in FIG. 3C, concrete (C) is placed in a mold (not shown), and the tough material 30 to which the hardening retardant 120 is applied is buried. (A1) does not come into direct contact with the straining material (30).

Next, as shown in FIG. 3D, the exposed tensions 30 are released (cut) and separated from the fixture band located between the fixing belt and the reaction force band. The curing retardant 120 is installed in the concrete in which the prestress is cured. / In the non-synthetic section A1 applied, the prestress is not introduced.

At this time, in the concrete enclosing the tension member of the non-synthetic section A1, the released tension member is re-tensioned only to maintain the tension member in a straight state while the prestress is not introduced. The reason for this is that the tensions in the non-synthetic zone at the time of release may not be able to control quality because the tensions are suddenly released and the shape and position of the tensions are not restrained and the concrete may not be able to behave integrally with the poured concrete.

Therefore, it is not necessary to introduce a prestress, but it is re-tensioned only to constrain its position and shape.

[Concrete Structures Prepared by Prestress Introduction Method Using Non-Synthetic Section of Tension Material]

FIG. 4 shows a concrete structure having various cross sections with prestress introduced by the present invention.

As shown in FIG. 4A, a concrete structure 100a having an open bottom can be a concrete structure having a non-synthetic section in which no sheath or hardening retardant is installed / applied,

As shown in FIGS. 4B and 4C, the hollow box-type concrete structures 100b and 100c can be a concrete structure having a non-synthetic section in which the sheath or hardening retardant is installed /

As shown in FIG. 4D, a concrete structure 100d having an open top can also be a concrete structure having a non-synthetic section in which no sheath or hardening retardant is installed / applied,

As shown in FIG. 4E, a T-shaped concrete structure 100e having an open upper portion can also be a concrete structure having a non-synthetic section in which no sheath or hardening retardant is installed / applied,

As shown in FIG. 4F, it can be seen that a concrete structure having a non-synthetic section in which no sheath or hardening retarder is installed / applied as an I-shaped concrete structure 100f is also possible.

In addition, various types of concrete structures can be manufactured because it is possible to form various shapes by concrete pouring using formwork.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

20: Bed
30: tensile material 40: reaction force band
50: Settlement 60: Tension Jack
100, 100a, 100b, 100c, 100d, 100e, 100f: concrete structures
110: Sheets
120: Hardening retarder

Claims (4)

In the pre-stress introduction method by the pre-tension method,
(a) forming a non-synthesis zone (A1) by applying a curing retardant only to a part of the tensile material to maintain the non-composite state with the concrete;
(b) before the curing retarder is cured
The concrete which is filled with the tensioned material including the non-synthetic section A1 is cured and cured, and the tensed material is released to allow the prestress to be introduced into the cured concrete. In the concrete surrounding the tensioned material of the non-synthetic section A1, ; And
(c) curing the hardening retarder to make the hardening retardant outside the tensile material cure in the non-synthetic section (A1) so that the hardening retardant cures and integrates with the concrete. . The method according to claim 1,
In the step (b), the method further comprises a step of re-tensioning the released tension material so that the prestress is not introduced into the concrete surrounding the tension material of the non-combining section (A1) A method of introducing a prestress using a non - synthetic interval. In a concrete structure designed to introduce a prestress by a pre-tensioning method,
Tensions placed inside; And concrete, which is formed by being cured so as to be embedded in the prestressing material, and which is made to introduce prestressing by the prestressing material,
The pre-
(a) forming a non-synthesis zone (A1) by applying a curing retardant only to a part of the tensile material to maintain the non-composite state with the concrete; (b) pouring and curing the concrete so that the tensioned material including the non-synthetic section (A1) is buried before the hardening retarder is hardened, releasing the tensioned material to allow the prestress to be introduced into the cured concrete, Preventing the prestress from being introduced into the concrete surrounding the tensions of the section A1; And (c) curing the hardening retarder so that the hardening retardant outside the tensile material in the non-synthetic section (A1) is cured and integrated with the concrete to make it behave. Concrete structures produced by the introduction method. The method of claim 3,
In the step (b), the method further comprises a step of re-tensioning the released tension material so that the prestress is not introduced into the concrete surrounding the tension material of the non-combining section (A1) A concrete structure manufactured by the method of introduction of prestress using non - synthetic section of.

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