KR102644694B1 - Pretension PSC piles with controlled rising - Google Patents

Abstract

The present invention arranges more strands on the tension side than on the compression side due to bending moment, but has a non-attached section where concrete is not attached to the tension side tendon, so that the rise span due to the tension side tendon can be reduced. Pretension PSC file is provided. According to a preferred embodiment of the present invention, the compression side tendons have a certain length and are arranged to receive a compressive force on the compression side at a position spaced a certain distance from the neutral axis, and the tension side tendons are arranged at a position spaced a certain distance away from the neutral axis. , the tension-side tendons are installed in concrete with a certain non-attached section at both ends, and the tension-side tendons are arranged in greater quantities than the compression-side tendons, so that the amount of downward deflection and the amount of upward rise due to the tension-side tendons are equal. do.

Description

Pretension PSC piles with controlled rising}

The present invention relates to a pretension PSC pile, and in particular, more strands are arranged on the tension side than on the compression side due to bending moment, but a non-attached section where concrete is not attached to the tension side tendon is left to prevent the rising span by the tension side tendon. It relates to pretensioned PSC files with controlled rise, which can be reduced.

While a typical PSC girder introduces additional prestress due to eccentricity (e) in addition to the axial compressive force due to tension material, the existing pre-tension type PSC pile has tension members arranged symmetrically on the upper and lower surfaces as shown in (a) of Figure 14. Since prestress is introduced only through compression force, excessive tension material is required for piles where bending moment acts on one side, and as shown in Figure 13, prestress is additionally introduced on the compression side due to bending moment, which has the disadvantage of reducing structural safety. there was.

In order to effectively respond to the bending moment acting on one side of the pile tension side, when trying to add prestress due to tension eccentricity like a general PSC girder, a rise occurred as shown in (b) of Figure 14, making pile construction impossible.

The technology behind the present invention to solve this problem is to introduce prestress to the half-section of the lower surface, which is the tension side, and add additional pressure to the remaining compression side, as proposed in Korean Patent No. 10-1940587 (Patent Document 1). An invention was designed to control the rise by pouring and completing the concrete, but there was the inconvenience of pouring additional concrete, and the additional pouring part had the disadvantage of not introducing prestress, so there was a possibility of cracks occurring during transportation and construction.

Korean Patent No. 10-1940587

The present invention arranges more strands on the tension side than on the compression side due to bending moment, but has a non-attached section where concrete is not attached to the tension side tendon, so that the rise span due to the tension side tendon can be reduced. The purpose is to provide pretensioned PSC files.

According to a preferred embodiment of the present invention, the compression side tendons have a certain length and are arranged to receive a compressive force on the compression side at a position spaced a certain distance from the neutral axis, and the tension side tendons are arranged at a position spaced a certain distance away from the neutral axis. , the tension-side tendons are installed in concrete with a certain non-attached section at both ends, and the tension-side tendons are arranged in greater quantities than the compression-side tendons, so that the amount of downward deflection and the amount of upward rise due to the tension-side tendons are equal. do.

In addition, a transmission length reduction device is installed at the boundary between the non-attached section and the attached section of the tension side tendon.

In addition, the transmission length reduction device is characterized by being composed of a synthetic fixing part that increases the pressure area while fixing the position of the tension-side tension member and a tension material fixing part that fixes the tension-side tension member.

In addition, the synthetic fixation part includes a longitudinal fitting plate inserted into a bundle of tension-side tendons through a longitudinal slot hole, and a longitudinal fitting plate fitted through a transverse slot hole into the same bundle of tension-side tendons and arranged to face the longitudinal fitting plate. It is characterized by being composed of a transverse fitting plate.

In addition, the synthetic fixation part is a plurality of longitudinal fitting plates that are respectively inserted through longitudinal slot holes in the tension-side tendon in opposite directions and arranged to overlap, and is located in the longitudinal arrangement section of the tension-side tension member to attach to the longitudinal fitting plate. It is characterized by being composed of steel plates for transverse fixation arranged in an interview.

In addition, the synthetic anchorage unit includes a pair of longitudinal fitting plates that have respective longitudinal slot holes inserted into the tension-side tension members, are disposed at regular intervals in the longitudinal direction of the PSC pile, and are interconnected by fitting plate supports, and a tension-side tension member. It is characterized in that it is composed of a plurality of transverse fitting plates, each of which has a transverse slot hole inserted in the transverse direction, and is arranged to face each other on a pair of longitudinal fitting plates.

In addition, the synthetic fixing part includes a plurality of pairs of longitudinal fitting plates, each of which has a longitudinal slot hole and is disposed at regular intervals in the longitudinal direction of the PSC pile and interconnected by a fitting plate support, and is inserted into the tension side tendon in different insertion directions. , It is characterized in that it is made by arranging a steel plate for transverse fixation that is faced on the front side of the flipped longitudinal fitting plate and is located in the longitudinal arrangement section of the tension side tendon.

In addition, the tension member fixing portion has a cylindrical hole into which the tendon member is inserted, and is disposed on the back side of the synthetic fixer and includes a cylindrical sleeve inserted into each tendon member, and at least one tension member fixing bolt that is screwed to the cylindrical sleeve and secures the tendon member. do.

In addition, the tension member fixing part has a long hole into which the tendon member is inserted, and is inserted into an adjacent tension member and includes a clamping bolt disposed on the back of the synthetic fixer, and is screwed to the clamping bolt to fix the tension member by pushing it to one end of the long hole with a tightening force. It is characterized by including a nut.

In addition, the tension member fixing part is characterized by being composed of a fixing wedge installed between the tension member and the steel plate hole of the composite fixing part.

According to the pretension PSC pile with controlled rise of the present invention, more strands are arranged on the tension side than on the compression side in order to respond to the bending moment acting on one side, but a non-attachment section is left where concrete is not attached to the tension member on the tension side. By reducing the rise span due to the tension side tendon, the amount of downward deflection due to the compression side tendon and the amount of upward rise due to the tension side tendon are equalized, making it possible to suppress the occurrence of rise when compressive force is introduced by pretension.

In addition, anchoring performance can be improved near the boundary between the non-attached section and the attached section inside the concrete through a transmission length reduction device that is composed of a synthetic anchor part and a tension material anchor part and is anchored and fixed to the concrete.

As a result, structural safety is improved in response to the bending moment acting on one side of the pretensioned PSC pile, and pile constructability is also improved by suppressing the occurrence of springing.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention along with the detailed description of the invention. Therefore, the present invention is limited to the matters described in the attached drawings. It should not be interpreted as limited.
1 is a conceptual diagram of a pretension PSC file with a transfer length reduction device according to the present invention.
Figure 2a is a diagram showing a state in which the first type of synthetic fixing part is installed in the pretension PSC pile of the present invention.
Figure 2b is a side view of Figure 2a.
Figure 3 is an exploded perspective view of the synthetic fixing portion shown in Figure 2a.
Figure 4 is a side view of a pretension PSC pile with a second type of synthetic fixing part installed according to the present invention.
Figures 5a (a) and (b) are a side view of a pretensioned PSC pile installed with a third type of synthetic fixer according to the present invention and a side plan view of the third type of synthetic fixer.
Figure 5b is an exploded perspective view of the third type of synthetic fixing part shown in Figure 5a.
Figure 6a is a side view of a pretension PSC pile installed with a fourth type of synthetic fixer according to the present invention.
Figure 6b is an exploded perspective view of the fourth type of synthetic fixing part shown in Figure 6a.
Figures 7 (a) and (b) are front and top views showing the installation state of the tension member fixing part of the first form according to the present invention.
Figures 8 (a), (b), and (c) are diagrams of the installation state of the tension member fixing part of the second type according to the present invention, showing a front view, a top view, and an enlarged view of the main portion.
Figure 9 is a diagram showing the installation state of the third type of tension member fixing part according to the present invention.
Figure 10 is a diagram of the change in the amount of downward deflection according to the introduction of compressive force of the compression side tendon according to the present invention.
Figure 11 is a diagram of the change in the amount of upward rise according to the introduction of compressive force of the tension side tendon according to the present invention.
Figure 12 (a) is a diagram showing the introduction of compression force on the tension side without the transmission length reduction device applied, and (b) in Figure 12 is a diagram of introduction of compression force on the tension side with the transmission length reduction device applied.
Figure 13 is a schematic diagram showing that a bending moment occurs on the compression side of a conventional PSC pile.
Figures 14 (a) and (b) are a schematic diagram in which tension members are installed symmetrically about the central axis in an existing pile and a schematic diagram showing the occurrence of a rise when more tension members are placed on the tension side.

Below, the present invention will be described in detail with reference to embodiments shown in the attached drawings, but the presented embodiments are illustrative for a clear understanding of the present invention, and the present invention is not limited thereto.

The pretension PSC file 10 of this embodiment has a constant length (L) as shown in FIG. 1 and is compressed to receive a first compression force (P1) on the compression side at a position spaced a certain distance (e ₁ ) from the neutral axis (C). The side tension members 12 are arranged and the tension side tension members 14 are arranged to receive the second compressive force (P2) on the tension side at a certain distance (e ₂ ) from the neutral axis. It is installed at both ends with a certain unattached section (L2, L2').

In order to form the non-attached sections (L2, L2') in this way, a method of covering the tendon with PVC pipe, hose, taping, etc. can be used, and then concrete is poured so that the tendon 14 is attached to the concrete 11. I made sure it didn't happen. The compression side tension member 12 and the tension member 14 may be strands, PS steel wires, reinforcing bars, steel bars, etc.

In addition, as shown in Figures 2 and 3, the tension side tendons 14 are arranged in greater quantities than the compression side tendons 12 so that the second compression force (P2) is greater than the first compression force (P1), By reducing the attachment length of the tension member, the downward deflection amount (D1) and the upward rise amount (D2) caused by the tension member on the tension side are configured to be equal.

In other words, it is possible to control the generated deformation by distinguishing the influence of the tendons 12 and 14 disposed on the tension side and the compression side and making the displacements caused by these two things the same. When producing a pile, the tension side is manufactured downward, and the compression side is manufactured upward.

Referring to Figure 10,

이 된다.(A) Downward deflection amount due to compression side tendon only

This happens.

Here, E is the concrete elastic modulus value of the pretensioned PSC pile 10, and I is its moment of inertia value.

Referring to Figure 11,

이 된다.(B) Upward surge due to tension side tendon material only

This happens.

At this time, due to the formation of the non-attached section (L2, L2'), the calculation section for the rise < the section for calculating the deflection due to the upper tension member (L ₁ < L).

≒0.7L이고 비부착구간 길이 L₂=L_2'≒0.15L로 형성하면 손쉽게 발생변형을 제어할 수 있다.For example, if e1=e2 and the number of tendons on the tension side is twice that of the compression side (P ₂ =2P ₁ ), and the strain on the tension side and compression side are the same, L ₁ =

If it is ≒0.7L and the length of the non-attached section is L ₂ =L _2' ≒0.15L, the resulting deformation can be easily controlled.

In addition, a transfer length reduction device 20 is installed at the boundary between the non-attached sections (L2, L2') and the attached section (L1) of the tension side tendon 14 to prevent the tendon and concrete from separating and moving.

In this way, by installing the transmission length reduction device 20 at the boundary between the non-attachment section (L2, L2') and the attachment section (L1), it is possible to smoothly introduce compressive force into the attachment section (L1) and reduce the transmission length. In a pretension member, the section where the force of the tendon to which the prestress is introduced is transmitted to the concrete occurs from the anchored end of the tendon, and the distance from the anchored end to the place where the effective prestress occurs in the concrete is called the transmission length. In this way, the present invention prevents the tension material and concrete from separating and moving by installing the transmission length reduction device 20 at the boundary between the attached section (L1) and the non-attached section (L2, L2'), and the non-attached section, which is the anchoring end. This makes it possible to reduce the transmission length from the end of (L2,L2'). Therefore, through the transfer length reduction device 20, it is possible to prevent the fixing performance from being greatly reduced near the boundary between the non-attached section (L2, L2') and the attached section (L1) inside the concrete.

The transmission length reduction device 20 includes a synthetic fixing part 22 that fixes the position of the tension-side tension member 14 and increases the pressure area, and a tension member fixing part 24 that fixes the end of the tension-side tension member 14. It is composed.

In the first form, as shown in Figure 2, the synthetic fixing part 22 includes a longitudinal fitting plate 221 disposed by being inserted into the tension side tendon 12 of the bundle through a longitudinal slot hole 221a, and a tension member of the same bundle. It consists of a transverse fitting plate 222 that is inserted into the side tension member 12 through a transverse slot hole 222a and is placed in contact with the longitudinal fitting plate 221. Therefore, the longitudinal fitting plate 221 and the transverse fitting plate 222 are buried in concrete 11 and synthesized by arranging a bundle of tension side tendons 12 at right angles to each other.

At this time, in order to prevent them from being separated from each other when pouring concrete, it is preferable that the longitudinal fitting plate 221 and the transverse fitting plate 222 are joined by tag welding or by fastening bolts and nuts.

In this way, when the longitudinal fitting plate 221 and the transverse fitting plate 222 are adhered, not only the overall thickness increases and is reinforced, but also the resistance area (bearing pressure area) to increase adhesion to concrete after removing the tensile force of the tension side tendon 12. ) can be increased to reduce the transmission length (L') as shown in Figure 12.

In the second form, as shown in FIG. 4, the synthetic fixing part 22 is inserted into the tension side tendon 14 in mutually opposite directions through longitudinal slot holes and includes a plurality of longitudinal fitting plates 221 and 221 arranged overlapping each other. ), and is located in the longitudinal arrangement section of the tension side tendon 14 and is composed of a transverse fixing steel plate 223 arranged to face the longitudinal fitting plate 221.

At this time, in order to prevent them from being separated from each other when pouring concrete, it is preferable that both the longitudinal fitting plates 221 and 221 and the transverse fixing steel plate 223 are joined by tag welding or joined through fastening of bolts and nuts. do.

Therefore, a plurality of longitudinal fitting plates (221 and 221) and a transverse fixing steel plate 223 are inserted into the tension-side tension members 12 arranged in a bundle, thereby increasing the overall thickness and not only reinforcing itself, but also tensile-side tension members ( 12) The acupressure force is increased, so the delivery length (L') can be reduced as shown in Table 1.

In the third form, as shown in FIG. 5, the synthetic fixing part 22 has each longitudinal slot hole inserted into the tension side tendon 14 and is arranged at regular intervals in the longitudinal direction of the PSC pile 10 to form a fitting plate. A pair of longitudinal fitting plates (221,221) each connected to each other by a support (221') and a transverse slot hole (222a) inserted laterally into the tension side tendon (14), respectively, and a pair of longitudinal fitting plates ( It is composed of a plurality of transverse fitting plates (222,222) arranged in parallel with each other (221,221).

Therefore, a pair of longitudinal fitting plates 221,221 and a plurality of transverse fitting plates 222,222 are embedded in the concrete 11 in a box shape via the fitting plate support 221', thereby providing structural stability and a larger area. By combining, the bearing pressure of the tension side tendon 12 can be increased and the transmission length (L') can be reduced.

In the fourth form, as shown in FIG. 6, the synthetic fixing parts 22 each have longitudinal slot holes 221a and are arranged at regular intervals in the longitudinal direction of the PSC pile 10 to serve as a fitting plate support 221'. A plurality of pairs of interconnected longitudinal fitting plates (221,221) are inserted into the tension-side tension member (14) with different insertion directions, and are interviewed on the front side of the flipped longitudinal fitting plate (221,221) to form a tension-side tension member (14). This is achieved by arranging a steel plate 223 for transverse fixation located in the longitudinal arrangement section.

In this case as well, a pair of longitudinal fitting plates (221,221) and transverse fitting plates (222,222) are embedded in the shape of a box in the concrete (11) via the fitting plate support (221'), thereby providing structural stability and a larger area. By combining, the bearing pressure of the tension side tendon 12 can be increased and the transmission length (L') can be reduced.

On the other hand, the tension member fixing part 24 has a cylindrical hole 242a into which the tension member 14 is inserted as shown in FIG. 7 and is disposed on the front side of the synthetic fixing part 22 and inserted into each tension member 14. It may be composed of a cylindrical sleeve 242 and at least one tendon fixing bolt 244 that is screwed to the cylindrical sleeve 242 and secures the tendon 14.

Therefore, when prestress is introduced, the tension side tendon 14 is fixed to the cylindrical sleeve 242 by the tightening friction of the tension member fixing bolt 244, and the cylindrical sleeve 242 is firmly fixed without movement on the front side of the synthetic fixing part 22. It can be established.

The tension member fixing part 24 is of another form and has a long hole 246a into which the tension side tension member 14 is inserted as shown in FIG. 8 and is inserted into the neighboring tension members 14 and 14 and placed on the front side of the synthetic anchorage part 22. It may be composed of a clamping bolt 246 and a tension member fixing nut 248 that is screwed to the clamping bolt 246 and pushes and secures the tension member 14 to one end of the long hole 246a with a tightening force.

In this case as well, the tension side tendon 14 is fixed to the clamping bolt 246 by the tightening friction of the tension member fixing nut 248, and the clamping bolt 246 is firmly fixed without movement on the front of the synthetic fixing part 22. You can do it.

In another form, as shown in FIG. 9, the tension member fixing part 24 may be composed of a fixation wedge 252 installed between the tension member 14 and the steel plate hole of the composite fixation part 22. In this case, the anchoring wedge 252 can bite the tendon member 14 and anchor it to the steel plate of the composite anchoring portion 22 without movement. Here, the steel plate hole refers to a hole formed in the above-described fitting plates 221 and 222 or the steel plate 223 for transverse fixation.

In this way, the pretension PSC pile 10 of the present invention arranges more strands on the tension side than the compression side to respond to the bending moment acting on one side, but has a non-attached section (L2, L2) in which concrete is not attached to the tension member on the tension side. ') is placed to reduce the rise span due to the tension side tendon so that the amount of downward deflection due to the compression side tendon is equal to the amount of upward rise due to the tension side tendon, making it possible to suppress the rise when compressive force is introduced by pretension.

In addition, the non-attached section (L2.L2') and the attached section (L1) inside the concrete are formed through the transmission length reduction device (20), which is composed of a synthetic fixing part (22) and a tension material fixing part (24) and is fixed and fixed to the concrete. Fixation performance can be improved near the boundary.

As a result, structural safety is improved in response to the bending moment acting on one side of the pretension PSC pile (10), and pile constructability is also improved by suppressing the occurrence of springing.

So far, the present invention has been described in detail with reference to the presented embodiments, but those skilled in the art can make various variations and modifications without departing from the technical spirit of the present invention with reference to the presented embodiments. will be. The present invention is not limited by such variations and modifications, but is limited by the claims appended below.

10: PSC file
20: Transmission length reduction device
22: Synthetic fixation unit
221: longitudinal fitting plate
221a: longitudinal slot hole
222: Transverse fitting plate
222a: transverse slot hole
223: Steel plate for transverse fixation
24: Tension member fixing part
242: Cylindrical sleeve
244: Tension member fixing bolt
246: clamping bolt
246a: Jang Gong

Claims (10)

The compression side tension member 12 is arranged to receive a compressive force (P1) on the compression side with a certain length (L) and a certain distance (e ₁ ) from the neutral axis (C), and is a certain distance (e ₂ ) from the neutral axis. The tension-side tension members 14 are arranged at positions spaced apart from each other by a distance of ) is arranged in a larger quantity than the compression side tendon (12) so that the downward deflection amount (D1) and the upward rise amount (D2) due to the tension side tendon (14) are equal. A pretension PSC with controlled rise. file. According to clause 1,
A pretension PSC file with controlled rise, characterized in that a transmission length reduction device (20) is installed at the boundary between the non-attached section (L2, L2') and the attached section (L1) of the tension side tension member (14). According to clause 2,
The transmission length reduction device 20 is composed of a synthetic fixing part 22 that increases the pressure area while fixing the position of the tension-side tension member 14 and a tension member fixing part 24 that fixes the tension-side tension member 14. A pretensioned PSC file with controlled rise. According to clause 3,
The synthetic fixation unit 22,
A longitudinal fitting plate 221 is inserted into the bundle of tension-side tendons 12 through longitudinal slot holes 221a, and is inserted into the tension-side tendons 12 of the same bundle through transverse slot holes 222a. A pretensioned PSC pile with controlled rise, characterized in that it consists of a transverse fitting plate (222) arranged in an interview with a longitudinal fitting plate (221). According to clause 3,
The synthetic fixation unit 22,
A plurality of longitudinal fitting plates (221 and 221) are respectively inserted through longitudinal slot holes in the tension-side tendon 14 in opposite directions and arranged overlapping, and are located in the longitudinal arrangement section of the tension-side tendon 14. A pretensioned PSC pile with controlled rise, characterized in that it consists of a transverse fixing steel plate (223) arranged in an interview on a longitudinal fitting plate (221). According to clause 3,
The synthetic fixation unit 22,
A pair of longitudinal fitting plates ( 221,221) and a plurality of transverse fitting plates (222,222) each having a transverse slot hole (222a) inserted laterally into the tension side tension member (14) and arranged in a face-to-face manner on a pair of longitudinal fitting plates (221,221). ) A pretension PSC file with controlled rise, characterized in that it consists of. According to clause 3,
The synthetic fixation unit 22,
A plurality of pairs of longitudinal fitting plates 221, 221, each having a longitudinal slot hole 221a, arranged at regular intervals in the longitudinal direction of the PSC pile 10 and connected to each other by a fitting plate support 221', are aligned in the insertion direction of each other. Alternatively, a transverse fixing steel plate 223 is inserted into the tension-side tension member 14, is interviewed on the front side of the flipped longitudinal fitting plate 221, and is located in the longitudinal arrangement section of the tension-side tension member 14. A pretension PSC file with controlled rise, characterized in that it is made by. According to clause 3,
The tension member fixing part (24) is
A cylindrical sleeve 242 is disposed on the front side of the synthetic fixing part 22 and has a cylindrical hole 242a into which the tendon 14 is inserted and is inserted into each tendon 14, and is screwed to the cylindrical sleeve 242. A pretension PSC file with controlled rise, characterized in that it includes at least one tendon fixing bolt (244) for fixing the tendon (14). According to clause 3,
The tension member fixing part (24) is
A clamping bolt 246 that has a long hole 246a into which the tendon 14 is inserted is inserted into the adjacent tendons 14 and 14 and is disposed on the front side of the synthetic anchorage part 22, and is screwed to the clamping bolt 246. A pretension PSC file with controlled rise, characterized in that it includes a tension member fixing nut (248) that pushes and secures the tension member (14) to one end of the long hole (246a) with a tightening force. According to clause 3,
The tension material fixing part 24 is a pretension PSC pile with controlled rise, characterized in that it is composed of a fixing wedge 252 installed between the tension material 14 and the steel plate hole of the synthetic fixing part 22.

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