KR101628632B1 - Dead Anchoring Method of Prestressing Strand - Google Patents

Dead Anchoring Method of Prestressing Strand Download PDF

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Publication number
KR101628632B1
KR101628632B1 KR1020150144014A KR20150144014A KR101628632B1 KR 101628632 B1 KR101628632 B1 KR 101628632B1 KR 1020150144014 A KR1020150144014 A KR 1020150144014A KR 20150144014 A KR20150144014 A KR 20150144014A KR 101628632 B1 KR101628632 B1 KR 101628632B1
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strand
concrete
exposed
sheath
outside
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KR1020150144014A
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Korean (ko)
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오두환
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안정생
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    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D2/00—Bridges characterised by the cross-section of their bearing spanning structure
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D2101/00—Material constitution of bridges
    • E01D2101/20—Concrete, stone or stone-like material
    • E01D2101/24—Concrete
    • E01D2101/26—Concrete reinforced
    • E01D2101/28—Concrete reinforced prestressed
    • E01D2101/285—Composite prestressed concrete-metal

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  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)

Abstract

The present invention has been made in order to solve the problems of the background art, and it is an object of the present invention to provide a fixing device for fixing a tension member inside a concrete structure, Is to provide a fixed fixing method for a stranded wire which is suitable for a case where a space for installation space is narrow but a long space for installation can be ensured in the longitudinal direction of the stranded wire.
The present invention relates to a fixed fixing method for a stranded wire, comprising: a beam producing step of producing a beam of a reinforced concrete material; In order to increase the bond strength between the exposed strand and concrete, one end of the strand is exposed to the outside of the sheath, and the surface of the strand is reinforced with concrete An embedding step of coating a particle-coated strand after coating with fine particles having a strength equal to or higher than the aggregate strength, in a state of being in direct contact with concrete without an internal fixing device; And a prestressing step of fixing the beam to the fixing device in a state where tensile force is applied to the strand after the concrete of the beam is cured to a predetermined strength so that the prestress acts on the beam. .

Description

Dead Anchoring Method of Prestressing Strand

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a fixing method of a strand which is most widely used as a tension member in a post-tensioned prestressed concrete, and more particularly, The present invention relates to a fixed fixing method of a stranded wire, which is suitable for a case where a mounting space is narrow in a plane direction perpendicular to a direction but a long installation space can be ensured in a longitudinal direction of the strand.

In the prestressed concrete, the post-tensioning method is free of the arrangement of the tension members because the tension member is installed on the concrete member and the tension is introduced after the concrete is cured. Therefore, this method can be easily applied even when a prestress is introduced into only a curved member or a part of a large member.

FIGS. 1A and 1B show a post tensioning method of arranging a tension member used in a simple beam structure in which a distributed load is applied. Figure 1 (a) shows a method of placing a tension member, which is often used in simple beams, in which the tension member 1 is arranged in a concave parabolic shape downward. The vertical distance from the center axis CL of the concrete member to the center of the tension member 1 is called the eccentric distance e of the tension member. This is because the bending moment acting on the simple beam in the case of a simple beam in which a distributed load is applied is the parabolic shape of the maximum moment, which is zero at both ends and becomes maximum at the center. A part of the resistance bending moment due to the tensile member 1 is proportional to the product of the tensile force of the tensile member 1 and the eccentric distance e of the tensile member. In this case, since the magnitude of the tensile force is almost constant, Thereby coping with a large acting bending moment at the center portion. In the case of FIG. 1B, the tension member 1 must be installed only at the bottom of the dotted line because of the sectional shape of the member and structural constraints. In this case, since the eccentric distance e is almost constant, To vary according to position, the magnitude of the tension must be changed. In other words, it is necessary to use a method in which a small tensional force is applied at the end portion and a large tensional force is applied at the center portion.

Figs. 2A to 2D are examples in which the arrangement of the tensions is restricted as in Fig. 1B, and the eccentric distance is almost constant over the entire length of the girder.

FIG. 2A is a cross-sectional view of a prestressed concrete U-shaped girder, in which the tension members 1 'on both sides are arranged on the upper and lower sides of the abdomen in a parabolic shape as shown in FIG. 1B, ), The eccentric distance becomes almost constant.

2B is an end cut-type low-type solid girder which is often used for ensuring a water supply cross-section in a bridge across a river, in which a part of the tension member 1 has to be tensioned and fixed at the low- It is the case that the eccentric distance is almost constant because it is inevitable to arrange the tension material straightly.

Fig. 2c is a sectional view of a steel composite girder made up of an upper steel material 3 and a lower prestressed concrete 4, so that the eccentric distance of the tension material 1 is almost constant since the prestressing material 1 has to be arranged in the lower concrete.

Fig. 2d is a cross-sectional view of the steel composite truss girder and is a section at the continuous focal point. Fig. The bottom current (5) and the workpiece (6) of the steel composite truss are steel pipes and the top (7) is U-shaped for easy operation of the bottom plate slab. (8) is filled in concrete (8), and in the case of phase current (7), compressive force acts at the central part of the span where the moment is applied, so that it simply fills the concrete (8) Since the tensile force acts, the prestress is introduced into the filled concrete by arranging the tensile material (1). That is, the phase current 7 near the continuous point portion is composed of a U-shaped section of the steel material and a composite structure of the prestressed concrete in the inside thereof. In this case, since the tensile material 1 is disposed in the upper current concrete, , It has almost constant eccentric distance. This steel composite truss is actually used mainly in the form of a space truss. The structural concept is the same as in Fig.

In order to effectively change the resistance bending moment due to the tensile material in the longitudinal direction in the case where a tensile material is to be placed in a concrete member having a small cross section as shown in FIGS. 2A to 2D and the eccentric distance can hardly be changed, do.

In order to change the compressive force of the concrete introduced by the tension member in the post-tensioning method, one end of the tension member must be fixed inside the concrete. 3 shows a method of applying a compressive force varying in the longitudinal direction of a member by using a dead anchor 9 provided inside the concrete and a live anchor 9 ' . As shown in Fig. 3 (d), the tension members 1A and 1B arranged in a plane in this manner exert a compressive force twice as much at the central portion as compared with the end portions. Fig. 3 (b) shows the magnitude of the compressive force acting on the beam by the tensile member 1A, Fig. 3 (c) shows the magnitude of the compressive force acting on the beam by the tensile member 1B, And the compressive force (C) acting on the beam.

Figs. 4A and 4B show an example of a fixed fixing device embedded in a concrete, wherein Fig. 4A is characterized by using a platen and Fig. 4B is characterized by bulbing the end of the strand. However, due to the large volume of the fixed fixing device, it is necessary to secure a sufficient space for accommodating the fixed fixing device in the concrete in order to install the fixed fixing device. However, it is practically impossible to install the fixing member in a long but narrow concrete member. In particular, additional reinforcement reinforcement is necessary because of the sudden change in local stress at the location of the fixed fixation device in the concrete. If the cross section is small, the placement of such reinforcement bars is impossible due to the minimum cover thickness and minimum rebar spacing requirement. Especially when many tension members are required to be placed on a small cross section, it is difficult to cope with this conventional internal fixed fixing method.

In the post-tensioning method, first, a sheath is embedded in concrete to form a tension duct, and when the concrete is cured, a tension member composed of a bundle of strands is inserted into the duct and tensioned and fixed. When the tension fixture is completed, the duct is grouted and the tension member and the concrete are adhered to each other. FIG. 3 shows an example using the post tension method. It is not easy to install an internal fixed fixing device of a tension member composed of a stranded bundle, and it is difficult to increase the number of ducts. However, if the applied compression force can be changed more depending on the position, it will be possible to cope with the action bending moment more efficiently. However, by virtue of the above-described method using a duct and bundle stranded wire, it is practically impossible to realize the change in the introduction compressive force of 3 or more.

FIG. 5 shows a method for fixing a tent in a concrete structure having a hybrid tendon structure and a method for manufacturing the same, which is a method of fixing a monotender composed of one strand of wire. As shown in FIG. 6, the monotender used herein is a coated strand with plastic sheath (HDPE coating) mounted on each strand. A grease is filled between the strand and the cover for greasing and lubricating. It is an unbonded strand that is not needed. In order to fix the coated strand, the coated strand and the grease are removed from the one end of the coated strand and the strand is exposed and fixed, thereby fixing the inside of the concrete. The tensioning method of the coated strand is a post tension method and the fixing method using the exposed wire portion 210 is called a hybrid tendency in the sense that it is the same as the strand fixing method in the pretensioning method. If the monotender is used instead of the bundle strand as shown in FIG. 3, the inner fixation position may be changed for each tensen as shown in FIG. 7, thereby easily changing the prestress acting along the longitudinal direction of the member . The graphs in FIG. 7 are based on the stress of the lower edge of the simple beam, and the outer parabola is the maximum allowable compressive prestress and the stepped graph is the maximum introduced compressive prestress. 7A shows a case in which a compression prestress is introduced into a beam by using two types of tension members 3a and 3b having different lengths of uncoated portion of the coated strand unblocked inside the beam, (b) shows a case where a compressive prestress is introduced into a beam by using three types of tension members (3a, 3b, 3c) having different lengths of the coated strand unbonded portion disposed inside the beam. In the plan view of the tensions shown in Fig. 7, the consideration for the symmetrical force action is omitted for convenience. 7C shows a case in which a compression prestress is introduced into a beam by using four types of tension members having different lengths of the coated strand unbonded portions disposed inside the beam, only the size of the compression prestress to be introduced is shown And the placement of the tensions is omitted for convenience of illustration. In Fig. 7 (c), the parabolic line inside the dotted line is the maximum allowable bending stress that can resist the bending moment due to the distribution load. As can be seen from FIG. 7, the fixed fixing method of the coated strand can easily introduce the required compressive prestress so that the structural efficiency of the prestressed concrete can be maximized even when the eccentricity of the prestressing material is almost constant

However, the fixed fixing method of the tension member as shown in FIG. 5 is different from the fixing method of the stranded wire in the pretensioning method. 8 is a graph for explaining the introduction length ( t ) and the fixing length ( d ) of the strand in the pretension mode. Introduction length concrete from the free end of the stress of tendons effective tension stress in the stress of tendons zero beams (girder) to release (release) the strand is stress for the introduction of the curing after the prestress that has been buried (f pe In this section, the tensile force of the tensile material is transferred to the compressive force of the concrete by the adhesive force between the tensile material and the concrete, and the prestress is gradually introduced. Development length is when additional load is applied to the concrete beam prestressed such attachment required for fixing the stress of such increased tendons (f ps) for any increase in stress in the tendons attached to the behavior in bending stress and acts on the concrete length. Usually, f ps, which is used when calculating the fixation length of the tensile material, is close to the tensile strength f pu of the tensile material. The graph of FIG. 8 is made up of two straight lines with different slopes, due to differences in the mechanism of adhesion between the tensions and the concrete. The adhesive force between the tension and the concrete is composed of the adhesion between the strand and the concrete, the friction, the twisted structure of the strand and the mechanical interlocking effect of the concrete. The tensile strength of the strand When released for the introduction of the prestress, the tensile force is reduced in the transmission length section, and the cross-sectional area of the tensioned material contracted due to tensile force during expansion increases, thereby improving the frictional force and mechanical engaging effect (Hoyer effect). However, in the section after the introduction length, due to the bending moment due to the additional load, the tensile stress of the tensile material becomes larger than that at the time of the introduction of the prestressing, so that the cross-sectional area of the tensile material is reduced. Conversely, adherence, frictional force and mechanical engaging effect are reduced. This is why the slopes of the two straight lines in the fusing length of Fig. 8 are different.

However, in the post tension method, since the tension member installed in an untensioned state is tensed after the concrete is cured, the graph of FIG. 8 has the same characteristics as the fixing period after the introduction length. In other words, when the tension is reduced, the cross-section of the tensions decreases, and the adhesion between the tensions and the concrete decreases. 8, the difference between the slopes of the two straight lines is approximately three times. Considering these characteristics, the calculated length of the exposed strand of the coated strand as shown in Fig. 5 is about 5 m in the case of the 15.2 mm diameter strand (SWPC 7C). Since no fixation method as shown in FIG. 5 has been used in the post tension method, the fixation length was calculated by using the pre-tension fixation length design method, and the fixed fixation test of the coated strand was performed. Before the tensile strength of the strand was reached, All of the strands were selected and failed to settle. It was assumed that the failure of the test was due to the fact that the grease was not completely removed during the removal of the coating of the coated strand and the removal of the grease. However, even if the experiment succeeded, the settlement length of about 5 m is too long to have applicability. Also, there is a problem that the complete removal of grease is virtually impossible to guarantee, but the biggest problem is that if the fixation of the tensions in the concrete member fails, the entire concrete member must be disposed of. Therefore, it is necessary to reduce the fixing length in order to improve the safety of the fixed fixing method of the tension member while improving the applicability.

The present invention has been made in order to solve the problems of the background art, and it is an object of the present invention to provide a fixing device for fixing a tension member inside a concrete structure, Is to provide a fixed fixing method for a stranded wire which is suitable for a case where a space for installation space is narrow but a long space for installation can be ensured in the longitudinal direction of the stranded wire.

As a means for solving the above-mentioned problems,

In the fixed fixing method of a stranded wire,

A beam forming step of forming a beam of reinforced concrete material;

The method of manufacturing a reinforced concrete beam according to claim 1, wherein the sheath and the strand are embedded in the beam in the process of manufacturing the reinforced concrete material beam, one end of the strand is exposed to the outside of the sheath, the protrusion is formed on the exposed strand, An embedding step of embedding the joined body in a state of being in direct contact with concrete without an internal fixing device; And

And a prestressing step of prestressing the beam by fixing the beam to a fixing device in a state where tensile force is applied to the strand after the concrete of the beam is cured to a predetermined strength. do.

The present invention also provides, as its second aspect,

In the fixed fixing method of a stranded wire,

A beam forming step of forming a beam of reinforced concrete material;

A sheath and a stranded wire are embedded in the beam in the process of manufacturing the beam of the reinforced concrete material, one end of the strand is exposed to the outside of the sheath, and the surface of the strand is deformed to increase the bond strength between the exposed strand and the concrete. An embedding step of coupling a release sleeve in the form of a protrusion of a reinforcing bar and embedding the strand combined with the release sleeve in a state of being in direct contact with the concrete without an internal fixing device; And

And a prestressing step of prestressing the beam by fixing the beam to a fixing device in a state where tensile force is applied to the strand after the concrete of the beam is cured to a predetermined strength. do.

According to a third aspect of the present invention,

In the fixed fixing method of a stranded wire,

A beam forming step of forming a beam of reinforced concrete material;

In order to increase the bond strength between the exposed strand and concrete, one end of the strand is exposed to the outside of the sheath, and the surface of the strand is reinforced with concrete An embedding step of coating a particle-coated strand after coating with fine particles having a strength equal to or higher than the aggregate strength, in a state of being in direct contact with concrete without an internal fixing device; And

And a prestressing step of prestressing the beam by fixing the beam to a fixing device in a state in which tensile force is applied to the strand after the concrete of the beam is cured to a predetermined strength. do.

In the three types of invention described above

The sheath may be a coated form of a coated strand or a tube form containing a strand bundle therein.

In the first aspect of the present invention, it is preferable that the stranded wire and the deformed rod are coupled to each other by a sleeve swaging joint which surrounds the connection portion between the stranded wire and the deformed rod and the sleeve.

In the second aspect of the present invention, it is preferable that the strand and the release sleeve are coupled to each other by a swaging method for pressing the release sleeve surrounding the strand.

In the third aspect of the present invention described above, the particles are preferably silica particles.

According to the present invention, it is possible to introduce a large compressive prestress by arranging a plurality of stranded wires in a small cross section by fixing it in the concrete without using a conventional fixed fixing apparatus which is complicated and bulky, A changing tension force can be easily introduced.

Figs. 1A and 1B are diagrams for explaining a method of arranging a strand of a post tension type used in a simple beam structure in which a distributed load acts. Fig.
Figures 2a to 2d show examples of structures in which the eccentric distance is almost constant over the entire length of the girder due to the arrangement constraints of the stranded wire.
3 is a view for explaining a method of providing a fixed fixing device inside a concrete to apply a compressive force varying in the longitudinal direction of the member.
4A and 4B are views showing an example of a fixed fixing device used in Fig. 3;
5 is a view for explaining a conventional fixed fixing method of a hybrid tent.
6 is a view for explaining the structure of a coated strand.
7 is a view for explaining the allowable compressive prestress and the maximum introduced compressive prestress of the lower beam according to the degree of change of the fixation position of the coated strand.
FIG. 8 is a view for explaining a transfer length and a development length of a strand in a pretension mode; FIG.
9 is a view for explaining a fixed fixing method of a strand according to the first embodiment of the present invention.
FIG. 10 is a view for explaining a case where the sheath is in the form of a tube in the first embodiment shown in FIG. 9; FIG.
11 is a view for explaining a method of joining a deformed rod material having a larger cross-sectional area than a stranded wire in a sleeve swaging in the first embodiment.
12 is a view for explaining a fixed fixing method of a strand according to a second embodiment of the present invention.
13 is a view for explaining a fixed fixing method of a strand according to a third embodiment of the present invention.
FIG. 14A is a view for explaining an embodiment in which the second embodiment and the third embodiment of the present invention are used in combination; FIG.
14 (b) is a view for explaining an embodiment in which the first embodiment and the third embodiment of the present invention are used in combination.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings, and specific details for carrying out the present invention will be provided.

FIG. 9 is a view for explaining a fixed fixing method of a strand according to the first embodiment of the present invention, FIG. 10 is a view for explaining a case where the sheath is in the form of a tube in the first embodiment shown in FIG. 9, 11 is a view for explaining a method of joining a deformed bar material having a larger cross-sectional area than a stranded wire to a sleeve swaging in the first embodiment.

The present invention relates to a method for fixing a strand of a strand for fixing a strand of strand to the inside of a reinforced concrete beam, and a method for fixing a strand of strand according to the first embodiment of the present invention comprises a beam forming step, an embedding step and a prestening step .

The beam forming step is a step of producing a beam of reinforced concrete material. The beam is a structure containing a long reinforcing concrete material in one direction and is called a beam but can also be used as a girder. The beam may be a prestressed concrete girder having a U-shaped cross section as shown in FIG. 2A, a prestressed concrete girder having a cut end 2 at both lower ends of the beam as shown in FIG. 2B, 2c, or may be a member used in a steel composite truss girder as shown in FIG. 2d. The present invention can also be applied to a general prestressed concrete girder shown in FIG.

The beam is manufactured through a process of installing a concrete mold, placing reinforcing bars in the concrete, and placing / curing concrete, in the same manner as in the production of a general reinforced concrete beam or a girder.

The embedding step is a step of embedding the sheath 30a or 30b and the strand 10 in the beam before placing the concrete in the beam forming step. Since the embedding of the strand 10 and the sheath 30a or 30b in the beam is a general technique, the beam is not shown and only the form of the embedment strand 10 and the sheath 30 is shown in Figs. 9 and 10 .

In this embodiment, one end of the strand 10 is exposed to the outside of the sheaths 30a and 30b, and the exposed strand 10a is embedded in the beam in the form of a combined body with the deformable bar. Without the fixing device, it is buried in direct contact with the concrete constituting the beam. The other end 10b of the strand which is the opposite end of the exposed strand 10a is tensioned and fixed at the end surface of the beam or at the side of the end of the beam. Since tension and settlement of the strand are well known techniques, And are not shown in the drawings.

The deformable bar 20 may be a deformed bar or a FRP taut material having protrusions formed on a surface of a rod having a long length in one direction.

It is noted that the bonding of the deformable bar 20 with the exposed strand 10a is intended to increase the bonding strength and there is a considerable difference in bonding strength depending on the surface shape. In the bond strength test, a pull out test is used to pull out the tied material with a certain length until the bond is destroyed. In this experiment, an example of the bond strength test between the strand and the deformed steel was compared. The bond strength is about 3 MPa, and the bond strength of the deformed bar is about 26 MPa, which is 8 to 9 times different. The results of the full-out test show that the deviation is very large, but it is clear that the difference in bond strength between the strand-type stranded wire made of twisted wires and the deformed bar with protruding nodules is considerably large. The main reason for this difference is that the bearing effect by the nodule of the deformed bar is much more effective in improving the adhesion performance than the mechanical interlocking by the twisted structure of the stranded wire.

In the tensile force (fp) distribution graph of the tension member at the lower side of Fig. 9, the tensile force fp is decreased at a different reduction rate (slope) in the fixed fixing portion, and the reduction rate is proportional to the adhesion strength. In the case of constructing a linear fixed fixing part of a tensile material by only the exposed strand, the fixing length becomes too long (the distance from the point of intersection of the dotted line to the horizontal line) and the bonding strength As shown in the drawing, when the deformed bar having a much greater length than the strand is joined, the length of the fixing can be reduced by increasing the inclination.

Therefore, when the deformed bar 20 is coupled to the exposed strand 10a as in the present embodiment, it is possible to complement the disadvantage of the strand with small stiffness as the deformed bar, thereby remarkably reducing the fixing length.

The deformable bar 20 may be a deformed steel bar, a deformed steel bar (a steel bar having a projection similar to a projection of a deformed reinforcing bar to a steel bar), an FRP tension member, or the like.

In order to withstand the maximum tensile strength of a steel strand having a small tensile strength due to its small tensile strength, it is necessary to use a reinforcing steel having a larger cross-sectional area than that of the steel strand. Recently, a tensile strength of 700 MPa Since the steel (SD700) is produced and used domestically, it is possible to reduce the difference in cross-sectional area between the stranded wire and the deformed bar using high strength steel bars.

As the deformed steel bar, a threaded steel rod with a threaded screw can be used. The tensile strength of the threaded steel rod is about 1000 MPa, and the difference in cross sectional area between the stranded wire and the bar is further reduced.

In the case of FRP tensile material, it has a tensile strength almost equal to that of the stranded wire, though it varies somewhat depending on the type of fiber used. It is easy to adjust the bonding strength because the surface of the rod can be formed into various shapes.

A variety of mechanical joining methods can be applied to the method of joining the exposed strand 10a and the deformed bar 20 to each other. In this embodiment, the joined portion of the strand 10a and the deformed rod 20 is connected to a sleeve 40 A sleeve swaging joining method is used which is wrapped and compressed by applying a mechanical force. At this time, the tensile strength of the strand 10a and the deformed rod 20 may differ from each other (the tensile strength of the strand is different from the tensile strength of the deformed rod). In this case, It is possible to use a method of inserting the step-adjustment sleeve 41 on the surface of a member having a small cross-sectional area, and then connecting the sleeve 41 to the sleeve 40. The sleeve swaging joint equipment is small in size and can be easily used in the field.

The sheath may be a sheath 30a in the form of a non-adhered strand of sheath 30a as shown in Fig. 9 to prevent the beam and the stranded wire from adhering in the process of wrapping the stranded wire, And may also be a tubular sheath 30b that accommodates a strand bundle therein.

When the sheath is in the form of a tube for accommodating a bundle of strands, the deformed bar 20 may be connected to each of the plurality of exposed strands 10a as shown in FIG.

In the case of the sheath 30a in the form of a non-adhered strand of sheath 30a, it is sufficient to remove a portion of the sheath of the strand of sheath and wipe out the grease between the sheath and the strand in order to expose the strand, ), It is necessary to install it inside the beam with the stranded wire exposed, and to prevent the concrete from entering into the interior of the sheath.

In the prestressing step, the concrete of the beam is cured to a predetermined strength, and then the prestress is applied to the fixing device in a state in which a tensile force is applied to the strand, so that the prestress acts on the beam.

As described above, the strand at the opposite end of the exposed portion of the strand is exposed to the end surface of the beam or the side of the end of the beam, and after the tensile force is applied through this portion, the strand is fixed to the fixing apparatus. Even in the case of using a coated strand, the coating of the strand of the exposed portion of the beam at the end of the beam is removed for tension and settlement of the strand. Tension and settlement of tensions are a common skill, so further explanation is omitted.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

12 is a view for explaining a fixed fixing method of a strand according to a second embodiment of the present invention.

The method of fixedly fixing the strand of the strand according to the present embodiment includes a beam forming step, an embedding step and a prestressing step. Since the beam forming step and the prestressing step are substantially the same as the corresponding configurations of the first embodiment, I will explain.

The embedding step is a step of embedding the sheath 30 'and the strand 10' within the beam. The embedding of the strand 10 'and the sheath 30' inside the beam is a general technique, and thus the beam is not shown, and only the form of the strand 10 'and the sheath 30' are shown in FIG.

In this embodiment, one end of the strand 10 'is exposed to the outside of the sheath 30' and the exposed strand 10a 'is provided with release sleeves 20a', 20b ', 20c ', And the strand connected with the release sleeve is buried in the beam. The strand connected with the release sleeve is buried in a state of being in direct contact with the concrete constituting the beam without a separate internal fixing device.

The release sleeve makes low-height knots, so that too large back pressure does not act on each knot, and the length of the sleeve can be made very short to form one knot per one sleeve as shown in FIG. 12 (a) And a plurality of nodes may be formed in one sleeve by making the length of the sleeve a little longer as shown in FIG. 12 (b). In the case of FIG. 12 (b), it is also possible to use a sleeve preformed with a nodule or to swage using a die capable of forming a nod. As shown in FIG. 12 (c), it is also possible to sandwich the elongated sleeves previously formed with the corners in the strand and attach the glue 21 'between the strands and the sleeve by grouting.

The provision of the release sleeve on the surface of the strand 10a 'is intended to increase the bond strength with concrete as in the case of joining the deformed bar material in the previous embodiment. As described above, attention is paid to the fact that the adhesive strength of the deformed reinforcing bar is larger than that of the strand, so that a sleeve similar to the protrusion of the deformed reinforcing bar is bonded to the surface of the strand.

The method of coupling the release sleeve to the strand is similar to the method of the first embodiment described above in which the release sleeve is pressed with a mechanical force in the state of wrapping the surface of the strand, have.

The other end portion 10b 'of the stranded wire opposite to the exposed strand 10a' is taut and fixed at the end face of the beam or at the end side of the beam. The tension and fixation of the strand are the same as in the first embodiment A further explanation will be omitted.

On the other hand, FIG. 12 shows a sheath 30 'in the form of a coated strand, but a sheath (not shown) in the form of a tube for receiving a strand bundle as shown in FIG. 10 may be used. Will not be described.

Hereinafter, a third embodiment of the present invention will be described with reference to FIG.

13 is a view for explaining a fixed fixing method of a strand according to a third embodiment of the present invention.

Since the beam fixing step and the prestressing step are substantially the same as the corresponding configurations of the first embodiment and the second embodiment, the difference between the beam forming step, Only the embedding step will be described.

The embedding step is a step of embedding the sheath 30 "and the strand 10" inside the beam. The embedding of the strand 10 "and the sheath 30" inside the beam is a general technique, so the beam is not shown and only the form of the strand 10 "and the sheath 30" buried is shown in FIG.

In this embodiment, one end of the strand 10 "is exposed to the outside of the sheath 30" and the exposed strand 10a "is coated with hard particles such as sandpaper, And the strand coated with the particles is buried in a state of being in direct contact with the concrete constituting the beam without a separate internal fixing device.

Usually, a method of sticking hard silica particles to the surface of a member by using a polymer (resin) is often used in the exposed strand 10a "in order to improve the adhesion performance of members attached to concrete. Particle coating The term " hard particles " used herein refers to particles having a strength equal to or higher than the concrete aggregate strength. Usually, particles used as an abrasive may be used.

When the particles are coated with the exposed strand 10a "using a polymer, the adhesion strength is increased. In particular, as shown in Fig. 13, in the case where the sheath is covered with a coated strand, the coating and grease are removed to form an exposed strand The grease on the surface of the strand is easy to remove but the grease remaining between the twisted strands is difficult to remove so that the residual grease may flow later and reduce the friction of the strand surface, Is applied to the surface of the strand and the particles are sprayed evenly, and then the polymer is applied to the particles again. Therefore, since the polymer completely seals the strand, it is possible to prevent the residual grease from leaking to the surface, There is also an effect.

The other end portion 10b "of the stranded wire opposite the end of the exposed strand 10a" is taut and fixed at the end surface of the beam or at the side of the end portion of the beam. The tension and fixation of the strand are accomplished by the first embodiment or the second embodiment The same explanation is omitted.

On the other hand, Fig. 13 shows a sheath 30 "in the form of a coated strand. As shown in Fig. 10, a sheath (not shown) in the form of a tube accommodating a strand bundle may be used. Will not be described.

14 (a) is a view for explaining an embodiment in which the second embodiment and the third embodiment of the present invention are used in combination, and Fig. 14 (b) Fig. 2 is a view for explaining an embodiment in which embodiments are used in combination. In FIG. 14 (b), a section enlarging member 21 like the enlarged head of a reinforcing bar is formed at the end of the deformable bar 20, which has the effect of further increasing the bonding strength with concrete.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments, The present invention can be embodied in various forms without departing from the scope of the present invention.

10: Strand 10a: Exposed strand
20: shaped rod 30: sheath

Claims (8)

In the fixed fixing method of a stranded wire,
A beam forming step of forming a beam of reinforced concrete material;
A sheath and a part of the strand are embedded in the beam while the one end of the buried strand is exposed to the outside of the sheath,
The method of claim 1, further comprising the steps of: forming an unfired strand and an elongated bar having a surface on a surface thereof,
An embedding step of exposing the remaining part of the strand to the outside of the beam; And
And a prestressing step of applying a tensile force to an end of the strand exposed to the outside of the strand after the concrete of the beam is hardened to a predetermined strength to fix the strand to the fixing device so that the prestress acts on the beam Of the fixing line.
In the fixed fixing method of a stranded wire,
A beam forming step of forming a beam of reinforced concrete material;
In order to increase the bond strength between the exposed strand and the concrete, one end of the buried strand is exposed to the outside of the sheath, and the other end of the strand is exposed to the outside of the sheath. In the process of manufacturing the reinforced concrete beam, And the reinforcing sleeve joined with the releasing sleeve is buried in a state in which it is in direct contact with the concrete without the internal fixing device,
An embedding step of exposing the remaining part of the strand to the outside of the beam; And
And a prestressing step of applying a tensile force to an end of the strand exposed to the outside of the strand after the concrete of the beam is hardened to a predetermined strength to fix the strand to the fixing device so that the prestress acts on the beam Of the fixing line.
In the fixed fixing method of a stranded wire,
A beam forming step of forming a beam of reinforced concrete material;
In order to increase the bond strength between the exposed strand and the concrete, one end of the strand is exposed to the outside of the sheath, and the surface of the strand is exposed to the outside of the sheath. Is coated with fine particles having a strength equal to or higher than that of concrete aggregate strength, and the strand coated with particles is buried in a state of being in direct contact with concrete without an internal fixing device,
An embedding step of exposing the remaining part of the strand to the outside of the beam; And
And a prestressing step of applying a tensile force to an end of the strand exposed to the outside of the strand after the concrete of the beam is hardened to a predetermined strength to fix the strand to the fixing device so that the prestress acts on the beam Of the fixing line.
4. The method according to any one of claims 1 to 3,
Wherein the sheath is in the form of a coated strand.
4. The method according to any one of claims 1 to 3,
Wherein the sheath is in the form of a tube for receiving a strand bundle therein.
The method according to claim 1,
Wherein the stranded wire and the deformed rod are connected to each other by a sleeve swaging joint which surrounds the connection part between the stranded wire and the deformed rod and the sleeve is compressed.
3. The method of claim 2,
Wherein the strand and the release sleeve are coupled to each other by a swaging method for pressing the release sleeve surrounding the strand.
The method of claim 3,
Wherein the particles are silica particles.

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109057148A (en) * 2018-09-29 2018-12-21 中路杜拉国际工程股份有限公司 Ultra-high performance concrete is without regular reinforcement Prestressed U type beam and its construction method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007040052A (en) * 2005-08-05 2007-02-15 Kajima Corp Steel for unbonded prestressed concrete, its manufacturing method and structure
JP2007314970A (en) * 2006-05-24 2007-12-06 Sumitomo Denko Steel Wire Kk Fixing structure with jump preventing mechanism of pc steel bar
KR20100043165A (en) * 2010-02-04 2010-04-28 스미토모 덴코 스틸 와이어 가부시키가이샤 Saddle system and cable for tension
KR101471648B1 (en) * 2013-04-11 2014-12-10 주식회사 포스코건설 Concrete structure including hybrid tendon structure and manufacturing method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007040052A (en) * 2005-08-05 2007-02-15 Kajima Corp Steel for unbonded prestressed concrete, its manufacturing method and structure
JP2007314970A (en) * 2006-05-24 2007-12-06 Sumitomo Denko Steel Wire Kk Fixing structure with jump preventing mechanism of pc steel bar
KR20100043165A (en) * 2010-02-04 2010-04-28 스미토모 덴코 스틸 와이어 가부시키가이샤 Saddle system and cable for tension
KR101471648B1 (en) * 2013-04-11 2014-12-10 주식회사 포스코건설 Concrete structure including hybrid tendon structure and manufacturing method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109057148A (en) * 2018-09-29 2018-12-21 中路杜拉国际工程股份有限公司 Ultra-high performance concrete is without regular reinforcement Prestressed U type beam and its construction method

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