KR101795889B1 - Prestressed girder and manufacturing method of prestressed girder - Google Patents

Prestressed girder and manufacturing method of prestressed girder Download PDF

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KR101795889B1
KR101795889B1 KR1020150185470A KR20150185470A KR101795889B1 KR 101795889 B1 KR101795889 B1 KR 101795889B1 KR 1020150185470 A KR1020150185470 A KR 1020150185470A KR 20150185470 A KR20150185470 A KR 20150185470A KR 101795889 B1 KR101795889 B1 KR 101795889B1
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South Korea
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segment
center
girder
tension force
stress
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KR1020150185470A
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Korean (ko)
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KR20170075923A (en
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김진국
양준모
최유복
안기성
성택룡
김태균
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주식회사 포스코
한국철도시설공단
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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
    • 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)
  • Bridges Or Land Bridges (AREA)
  • Rod-Shaped Construction Members (AREA)

Abstract

The present invention relates to a pneumatic tire comprising a first concrete member, a pair of end segments embedded in the first concrete member and having a first sheath tube formed in a predetermined direction; A second concrete member, a plurality of stranded wires installed in a straight line and embedded in the second concrete member to introduce a pre-tension force, and a plurality of stranded wires connected to the first sheath pipe, A center segment having a second sheath tube formed in a predetermined direction embedded in the center segment; And a tendon member which is provided to penetrate the end segment and the center segment and introduces a post tension force in a predetermined direction to connect the pair of end segments to the center segment, The post tension force introduced into the end segment is set so as to exceed a maximum tensile stress of a girder lower edge having a maximum value at a connection portion between the end segment and the center segment and to be within an allowable stress, The pretension force introduced into the center segment is obtained by subtracting the post tension force introduced by the compressive stress introduced into the center segment by the tensile member at the maximum tensile stress 2 of the lower edge of the girder having the maximum value at the center of the center segment Value and is within the allowable stress. Thereby providing a prestressed girder for gaging.

Figure R1020150185470

Description

[0001] PRESTRESSED GIRDER AND MANUFACTURING METHOD OF PRESTRESSED GIRDER [0002] BACKGROUND OF THE INVENTION [0003]

The present invention relates to a prestressed girder and a method of manufacturing a prestressed girder that can reduce the amount of introduction of a prestress of a girder.

It should be noted that the contents described in this section merely provide background information on the present invention and do not constitute the prior art.

The girder is installed on the upper part of the pier so that the bridge can secure the load-bearing capacity, and the concrete slab is placed on the bridge. Such a girder is a prestressed concrete girder manufactured by introducing a tension force to increase the load bearing capacity of a bridge or to resist deflection or crack generated by overload or use.

Prestressed concrete girder is a structure that can resist tensile force by introducing precompression force to concrete girder by using high strength steel wire to compensate characteristic of concrete which is vulnerable to tensile. In this case, as the length of the bridge increases, the height and width of the concrete section become larger in order to secure the rigidity and strength. In order to introduce the prestress into the enlarged section, tens of stranded wires should be installed.

Prestressed concrete and post tensioning methods are available for manufacturing prestressed concrete girders.

The pre-tension method is a method in which the steel wire is arranged in the longitudinal direction in advance, the concrete is laid after the tension is introduced, the concrete is hardened, and then the compressive stress is introduced into the concrete by releasing the tension force. In the post tension method, It is a method to introduce compressive stress to concrete by installing in advance, pouring concrete, hardening concrete, inserting steel wire and fixing tension on the end of concrete by introducing tension force.

The pretensioning method is advantageous in terms of quality and construction when it is manufactured and transported in a large quantity. However, since the steel wire must be strained in advance, it takes a lot of production equipment such as reaction force and long line bed, The post tension method is widely applied except that it can not be carried by a girder having a length of 15 m or more and is applied to a girder having a length less than that or applied to a girder manufactured in the field.

Fig. 1 is a view showing a distribution of bending stress due to a design load applied to the girder 1. When an external force acts on the girder, a bending stress in the form of a parabola may occur.

FIG. 2 is a view showing a conventional girder 1 in which a prestress is introduced in consideration of the bending stress of FIG. 1. In the prior art, a tension member for generating a post tension force is disposed in consideration of a distribution shape of a bending stress applied to a girder So as to support the bending stress applied to the girder.

Therefore, since 30 to 40 or more stranded wires are disposed in the girders installed in the bridges, a plurality of sheath tubes and fixing members are installed at the ends of the girders, and the cross section of the girders is excessively large.

3 is a view showing a difference between a bending stress distribution according to Fig. 1 and a prestressing force introduced by Fig. 2

As shown in FIG. 3, the distribution of the bending stress due to the design load applied to the girder of FIG. 1 and the distribution of the introduction amount of the post tension force are formed differently, and the post tension force G is excessively increased toward the end region of the girder There is a problem that the construction cost is wasted as the excessive design area X1 is formed.

Therefore, it is necessary to develop a prestressed girder which can optimize the introduction amount of the prestress introduced into the girder so as to correspond to the bending stress caused by the design load applied to the girder.

An aspect of the present invention is to provide a method of manufacturing a prestressed girder which can reduce the construction cost by optimizing the amount of introduction of the prestress according to the distribution of the bending stress due to the design load applied to the girder.

According to an aspect of the present invention, there is provided a method of manufacturing a concrete structure, comprising: a first concrete member; a pair of end segments embedded in the first concrete member and having a first sheath tube formed in a predetermined direction; A second concrete member, a plurality of stranded wires installed in a straight line and embedded in the second concrete member to introduce a pre-tension force, and a plurality of stranded wires connected to the first sheath pipe, A center segment having a second sheath tube formed in a predetermined direction embedded in the center segment; And a tendon member which is provided to penetrate the end segment and the center segment and introduces a post tension force in a predetermined direction to connect the pair of end segments to the center segment, The post tension force introduced into the end segment is set so as to exceed a maximum tensile stress of a girder lower edge having a maximum value at a connection portion between the end segment and the center segment and to be within an allowable stress, The pretension force introduced into the center segment is obtained by subtracting the post tension force introduced by the compressive stress introduced into the center segment by the tensile member at the maximum tensile stress 2 of the lower edge of the girder having the maximum value at the center of the center segment Value and is within the allowable stress. Thereby providing a prestressed girder for gaging.

Preferably, the second sheath pipe is provided at a lower side of the central region of the cross section in the width direction of the second concrete member, the stranded wire is disposed below the cross section in the width direction of the second concrete member, Direction. ≪ / RTI >

Preferably, the tendon member and the second sheath pipe are formed so that the center thereof is curved downward, and the stranded wire may be disposed lower than a top end height of the second sheath pipe at a downward curved point of the second sheath pipe.

In accordance with another aspect of the present invention, there is provided a method of manufacturing a concrete structure, comprising: a first concrete member; a pair of end segments embedded in the first concrete member and having a first sheath tube formed in a predetermined direction; A second concrete member, a plurality of stranded wires installed in a straight line and embedded in the second concrete member to introduce a pre-tension force, and a plurality of stranded wires connected to the first sheath pipe, A center segment having a second sheath tube formed in a predetermined direction embedded in the center segment; And a tension member installed through the end segment and the center segment and introducing a post tension force in a predetermined direction to connect the pair of end segments to the center segment, , Determining the length of the end segment so that the magnitude of the post tensioning force introduced by the tendon member in the total span of the prestressed girder is greater than the maximum design external force applied to the end segment and the generated stress is within an allowable stress An end span determining step; And a sum of a magnitude of a post tension force introduced by the tendon member determined in the end span determination step and a magnitude of a pre-seating force introduced in the central segment exceeds a maximum design external force applied to the center segment, And determining a length of the center segment so that the center segment is within a predetermined range of stress, wherein the post-tension force introduced into the end segment by the tendon member is determined by the post- Wherein the prestressing force introduced by the plurality of stranded wires is set so that the maximum tensile stress of the girder lower edge at the connecting portion of the segment exceeds the maximum tensile stress of 1 and is within an allowable stress, The maximum tensile stress 2 at the lower edge of the girder having the maximum value at the center of the girder By Southern member exceeds the value obtained by subtracting the post-tensioning force that is introduced by the compression stress to be introduced into said central segment, and provides a process for the production of prestressed girder, characterized in that which is set such that the allowable stress.

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Preferably, the step of fabricating the end segment according to the post-tension force determined in the step of determining the end span and the length of the end segment; A center segment forming step of fabricating the center segment according to the pre-tension force determined in the center span determining step and the length of the center segment; And joining the first sheath tube and the second sheath tube in a state where the end segment is disposed at both ends of the center segment, and introducing a post tension force in a state in which the tendon member is disposed have.

Preferably, pretensioning may be introduced while a plurality of stranded wires installed in the central segment are installed on the entire length of the central segment without contacting the second concrete member in a non-attached section.

Preferably, the end segment making step and the center segment making step are such that the second concrete member of the center segment has a strength equal to or greater than that of the first concrete member of the end segment, .

Preferably, the segment bonding step includes: a segment transporting step of transporting the pair of end segments fabricated in the end segment manufacturing step and the center segment fabricated in the center segment manufacturing step to a construction site; A segment arrangement step of arranging the end segments at both ends of the central segment; A tension member mounting step of inserting a tension member of the tension member over the end segment and the central segment and disposing the fixing member of the tension member provided at both ends of the tension member; And a post tension introduction step of tightening the tension member inserted in the first sheath tube and the second sheath tube to fix the fixing member to the end segment in a state in which the post tension force is introduced .

Preferably, the step of forming a bonding paint layer includes coating and curing a bonding paint on a connecting portion between the end segment and the center segment between the segment placing step and the post tension introduction step before the post tension introduction step Of the prestressed girder.

According to one embodiment of the present invention, by applying a compressive stress to the end region and the central region of the prestress girder differentially in accordance with a design load acting differently along the longitudinal direction of the prestress girder, There is an effect that can be done.

According to the embodiment of the present invention, it is possible to assemble the split type segments integrally by the introduced post tension force, and to shorten the construction period by constructing the girders by the simple method.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing distribution of bending stress due to a design load applied to a girder. Fig.
FIG. 2 is a view showing a conventional girder in which a prestress is introduced in consideration of the bending stress due to the design load of FIG. 1. FIG.
3 is a view showing the difference between the bending stress distribution due to the design load of FIG. 1 and the prestressing force introduced by FIG. 2. FIG.
FIG. 4 is a view showing a prestress girder according to the present invention in which a prestress is introduced in consideration of the bending stress due to the design load of FIG. 1. FIG.
5 is a graph showing the relationship between the maximum design external force generated at the center portion of the prestressed girder and the prestressing force (pre-compression force + post tensioning force) introduced at the center of the prestressed girder of the present invention, Is generated and a redundant compressed area is generated in the center segment.
FIG. 6 is a view showing the prestressing force introduced into the prestressed girder of the present invention by dividing the prestressing force into a pre-tension force and a post-tension force.
FIG. 7 is a view showing a prestressed girder and a introduced prestressing force in a state where a tensile generation region is not formed in an end segment, unlike FIG. 5, by the method of manufacturing a prestressed girder of the present invention.
Fig. 8 is a view showing a cross section of the prestressed girder according to the present invention in a direction AA 'in the center part. Fig.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. The shape and size of elements in the drawings may be exaggerated for clarity.

Hereinafter, a prestressed girder according to an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 4, a prestressed girder according to an embodiment of the present invention may include a pair of end segments 100, a central segment 200, and a tendon member 300.

The prestressed girder includes a pair of end segments 100 having a first concrete member 110, a first sheath pipe 130 embedded in the first concrete member 100 and formed in a predetermined direction, A plurality of stranded wires 250 installed between the segments 100 and installed in the form of a straight line embedded in the second concrete member 210 and introducing a pretensioning force, And a second sheath pipe (230) communicating with the sheath pipe (130) and embedded in the second concrete member (210) and formed in a predetermined direction, and a second sheath pipe And a tension member 300 installed through the segment 200 and formed in a predetermined direction and introducing a post tension force to the end segment 100 and the center segment 200. [

In the end segment 100, the post tension force introduced by the tendon member 300 is greater than the maximum design external force applied to the end segment 100 and the generated stress is within an acceptable level, 200 is configured such that the sum of the magnitude of the post tension force introduced by the tension member 300 and the magnitude of the pre-switching force introduced by the plurality of stranded wires 250 is greater than the sum of the magnitude of the pre- It is larger than the maximum design external force applied and the generated stress can be within the allowable level.

4, the post tension force F1 introduced by the tendon member 300 at the total span of the prestressed girder is greater than the maximum design external force applied to the end segment 100, The length L1 of the end segment may be determined such that the stress is within an allowable stress.

The sum of the magnitude of the post tension force F1 introduced by the tendon member 300 and the magnitude of the pre-seating force introduced by the plurality of stranded wires 250 is the maximum The length L2 of the central segment may be determined such that the generated stress is greater than the design external force and the generated stress is within the allowable stress.

The prestressed girder according to the present invention can be manufactured by assembling the end segments 100 and the center segments 200 at a factory, joining the segments together at the site, and installing the tension members 300 in the longitudinal direction.

Since each segment is manufactured in the factory, quality control is easy, and the manufacturing process is completed in the factory except for the connection of the segments and the introduction of the post tension force (F1), so that the construction period can be remarkably shortened, Since only a short-term small-scale assembly is required instead of a large production site in the field, the applicability is very excellent.

8, the second sheath pipe 230 is installed at a lower side of the central region of the cross section in the width direction of the second concrete member 210, and the strand 250 is formed in the width of the second concrete member 210 And may be disposed symmetrically with respect to the second sheath tube 230 in the width direction.

The central segment 200 includes a tension member 310 that applies a post tension force F1, a second sheath tube 230 that extends through the tension member 310, A plurality of stranded wires 250 are arranged in the longitudinal direction.

8, the second sheath pipe 230 through which the tension member 310 of the tension member 300 penetrates is provided below the central region of the width direction cross section of the second concrete member 210, A plurality of stranded wires 250 having pre-tension introduced in a symmetrical manner on both sides of the second sheath tube 230 may be disposed.

The tensile member 300 and the second sheath pipe 230 are curved downward and the strand 250 is bent at a downward curvature point of the second sheath pipe 230 so that the second sheath pipe 230 The height of the uppermost end of the tapered portion 22b.

This minimizes the thickness of the web member of the second concrete member 210 by placing the second sheath tube 230 within the lower flange within a possible range of the second concrete member 210 of the middle segment 200 So as to optimally design the cross section of the center segment 200.

The method of manufacturing the prestressed girder of the present invention and the constituent elements constituting the end segment 100 and the center segment 200 of the prestressed girder are not limited to the concrete member and the sheath pipe, May exist.

It goes without saying that, when the reinforcing bars are installed in the interior of the concrete member, the reinforcing bars can support the design load due to the bending stress applied to the prestressing girder.

Therefore, when reinforcing bars are additionally provided in the prestressed girder, the pre-tension force F2 introduced by the plurality of stranded wires 250 and the post tension force F1 introduced by the tension member 300, Of course, can be reduced.

The details of the prestressed girder of the present invention will be described below together with the description of the manufacturing method of the prestressed girder described below.

Hereinafter, a method of manufacturing a prestressed girder according to an embodiment of the present invention will be described in detail with reference to the drawings.

First, the concept of stress introduction in the method of manufacturing a prestressed girder of the present invention will be described first.

Fig. 1 is a view showing the distribution of bending stress E due to a design load applied to a girder.

As shown in FIG. 1, it can be seen that the maximum bending stress acts in the central region of the girder and the distribution of the bending stress becomes smaller toward the end direction.

As shown in FIG. 2, in order to cope with the bending stress (tensile stress of the girder lower edge) due to a design load acting differently according to the longitudinal direction of the girder, an equal prestress force F, Tension type or pre-tension type.

Fig. 3 is a diagram showing the distribution of the bending moment according to Fig. 1 and the difference of the prestress force F introduced by Fig. 2. Fig.

Accordingly, as shown in FIG. 3, in the conventional case, the post tension force F1 is excessively formed toward the end region of the girder, which results in a waste of construction cost due to excessive design.

4, according to the present invention, in the case of the end segment 100 disposed at both end regions of the girder, the post tension force F1 introduced by the tendon member 300 causes the design load of the girder Thereby supporting the bending stress exerted thereon.

The post tension force F1 introduced by the tendon member 300 and the pretension force F2 introduced in advance by the plurality of stranded wires 250 in the case of the center segment 200 disposed in the central region of the girder, So as to correspond to the bending stress applied by the design load.

The stress (f t ) of the girder girder is defined by the following equation (1), and the stress (f b ) of the lower girder is defined by the following equation (2).

Figure 112015126614099-pat00001
Equation (1)

Figure 112015126614099-pat00002
Equation (2)

The prestressed girder of the present invention should be designed so as to satisfy the equations (3) and (4).

Figure 112015126614099-pat00003
Equation (3)

Figure 112015126614099-pat00004
Equation (4)

Here, f t: the segment girders: girder upper edge stress, f b: girder lower edge stress, P: force introduced by the PC strands 250, A: girder terms the cross-sectional area, e: PC strands 250, eccentric, M d moment, y t: distance from the center of the girder to girder the upper edge (1-1), y b: distance from the center of the girder to the lower edge girder (1-2), f at: allowable tensile stress of the concrete, f ac: the concrete Allowable compressive stress.

And, the prestressed girder should be designed to satisfy f p = f at - f d > 0.

Where f p = f p1 + f p2 , f d = the tensile stress of the lower edge of the concrete caused by the design load of the girder, f p1 = the compressive stress of the lower edge of the concrete introduced by the pretension, f p2 = And the compressive stress of the underfloor of concrete.

4 to 6, a method of manufacturing a prestressed girder according to an embodiment of the present invention may include an end span determination step and a center span determination step.

As shown in FIGS. 4 and 8, the prestressed girder to which the prestressing method of the present invention is applied includes a pair of end segments 100, a central segment 200, and a tendon member 300 .

The present invention is directed to a pneumatic tire comprising a first concrete member (110), a pair of end segments (100) having a first sheath pipe (130) embedded in the first concrete member (110) A plurality of stranded wires 250 installed in a predetermined direction embedded in the second concrete member 210 and introducing a pretensioning force F2, And a second sheath pipe (230) communicating with the first sheath pipe (130) and embedded in the second concrete member (210) and formed in a predetermined direction, and a second sheath pipe And a tendon member 300 installed through the central segment 200 and formed in a predetermined direction to introduce a post tension force F1 to the end segment 100 and the center segment 200. [ A method of manufacturing a rest girder.

The method of manufacturing a prestressed girder according to the present invention is characterized in that the post tension force F1 introduced by the tendon member 300 at the total span of the prestressed girder is greater than the maximum design external force applied to the end segment 100 And determining a length L1 of the end segment so that the generated stress is within an allowable stress, and determining a post tension force F1 introduced by the tendon member 300 determined in the end span determination step, Of the center segment (200) is greater than the maximum design external force applied to the central segment (200) and the sum of the magnitudes of the pre-stress forces introduced in the central segment (200) And a center span determining step of determining the center distance L2.

4, the tendon member 300 may be installed in the post tension zone S1 formed over the end segment 100 and the central segment 200, and the plurality of strands 250 may be disposed in the middle segment < RTI ID = 0.0 > May be installed in a pre-tension section (S2) formed over the entire surface of the substrate (200).

Therefore, according to the present invention, compressive stress is introduced by the pre-tension force (F) differentially from the end region and the central region of the prestress girder depending on the design load acting differently along the longitudinal direction of the prestress girder, There is an effect that can be saved.

6, in the step of determining the end span, the post tension force F1 introduced into the end segment 100 by the tendon member 300 is applied to the end segment 100 and the center segment 200, The maximum tensile stress 1 (P1) of the lower edge of the girder having the maximum value at the connection portion of the girder can be set to be within the allowable stress.

6, the pre-tension force F2 introduced by the plurality of stranded wires 250 is determined by the maximum tension of the girder bottom having the maximum value at the center of the center segment 200, Can be set so as to exceed the value obtained by subtracting the post tension force F1 introduced by the compressive stress introduced into the central segment 200 by the tensile member 300 at the stress 2 (P2) and within the allowable stress .

Referring to FIG. 3, it can be seen that the maximum design external force exerted on the end segment 100 occurs at the connecting portion of the end segment 100 and the central segment 200.

The maximum design external force exerted on the end segment 100 may correspond to a maximum tensile stress 1 (P1) of the lower edge of the girder having a maximum value at the connection portion of the end segment 100 and the central segment 200. [

5 is a graph showing the relationship between the maximum design external force generated at the center of the prestressed girder and the prestress force F (pre-compression force + post tension force F1) introduced at the center of the prestressed girder of the present invention, In which the tensile generation region X2 is generated in the end segment 100 and the redundant compression generation region X3 is generated in the center segment 200. [

6, the post tension force F1 introduced into the end segment 100 by the tendon member 300 is set such that the tensile generation region X2 is not generated in the end segment 100 Should be set so as to exceed the maximum tensile stress 1 (P1) of the lower edge of the girder having the maximum value at the connection portion between the end segment 100 and the center segment 200 and within the allowable stress.

6 is a perspective view of a prestressed girder according to the present invention in which a prestressed girder in a state where a tensile generation region X2 is not formed in an end segment 100 and a prestressed girder F Fig.

6 further shows that the post tension force F1 is further introduced in the end segment 100 and the central segment (X2) is further introduced in the end segment 100 than in the case of Fig. 5 to prevent the tensile generation region X2 from occurring in the end segment 100 200, the pre-tension force F2 is reduced.

FIG. 6 is a diagram showing the prestressing force F introduced into the prestressed girder of the present invention by dividing the prestressing force F into a pre-tension force F2 and a post tension force F1.

6, the post tension force F1 introduced into the end segment 100 by the tendon member 300 so that the tensile generation region X2 is not generated in the end segment 100, It should be set so as to exceed the maximum tensile stress 1 (P1) of the lower girder having the maximum value at the connection portion between the end segment 100 and the center segment 200 and to be within the allowable stress.

The pretensioning force F2 introduced into the central segment 200 by the plurality of stranded wires 250 is greater than the tensile force F2 at the central portion of the central segment 200 so that the pretension amount is not excessively designed in the central segment 200. [ The transverse tensile force F1 of the girder lower edge of the girder having a maximum value minus the post tension force F1 introduced into the central segment 200 by the tensile member 300 at the maximum tensile stress P2, It may be more preferable that it is not designed so that it does not.

Accordingly, as shown in FIG. 7, the introduction stress reduction area X4 is generated in the end segment 100, thereby preventing excessive design of the post tension force F2, thereby optimizing the amount of introduction of the prestress to reduce the construction cost .

The method of manufacturing a prestressed girder of the present invention may include a step of manufacturing an end segment 100, a step of manufacturing a center segment 200, and a step of joining segments.

The method for manufacturing a prestressed girder according to the present invention is characterized in that the end segment 100 is manufactured according to the post tension force F1 determined at the end span determining step and the length L1 of the end segment, (200) for manufacturing the center segment (200) according to the pre-tension force (F2) and the length (L2) of the middle segment determined in the center span determination step, In the state where the end segment 100 is disposed at both ends of the segment 200 and the tendon member 300 is disposed by connecting the first sheath pipe 130 and the second sheath pipe 230, And a segment joining step of introducing the force F1.

It may be desirable that the manufacturing steps of the end segments 100 and the center segment 200 are preliminarily manufactured at a factory for improving the quality.

In the end segment 100, when the first sheath pipe 130 is disposed in the longitudinal direction of the first concrete member 110, the concrete is poured into the mold for forming the first concrete member 110, The first sheath pipe 130 may be installed inside the first sheath pipe 110.

The center segment 200 may be provided with a first sheath pipe 130 and a plurality of stranded wires 250 providing a pre-tension force F2 in the longitudinal direction of the second concrete member 210. [

The second sheath pipe 230 may be installed in the second concrete member 210 by placing the concrete in the formant for forming the second concrete member 210 in the state of the second concrete member 210. [

The pretensioning force F2 may be introduced by arranging a plurality of stranded wires 250 in the second concrete member 210 and providing a tensile force to the stranded wire 250 so that the second concrete member 210, The concrete is poured into the mold for forming the second concrete member 210 and the both ends of the strand 250 can be cut and the pre-tension can be introduced when the second concrete member 210 is placed and cured.

A plurality of stranded wires 250 installed in the central segment 200 are installed on the entire length L2 of the middle segment without contacting the second concrete member 210 in a non- Pretension can be introduced.

The manufacturing process of the end segment 100 and the manufacturing of the center segment 200 may be such that the second concrete member 210 of the center segment 200 is less than the first concrete member 110 of the end segment 100. [ The end segment 100 and the central segment 200 can be fabricated to have the same or greater strength.

This is because the post tension force F1 is introduced to the central segment 200 by the tendon member 300 and the pretension force F2 is introduced by the plurality of stranded wires 250, The present invention is also applicable to a prestressed girder having a longer span by reinforcing the central segment 200 in which the segment 200 is formed of a concrete member having a higher strength to generate a greater bending stress.

The end segment 100 is manufactured by manufacturing the end segment 100 such that the first concrete member 110 of the end segment 100 has an intensity in the range of 40 to 60 MPa, The center segment 200 may be fabricated such that the second concrete member 210 of the center segment 200 has an intensity in the range of 60 to 80 MPa.

The segment joining step may further include a segment conveying step, a segment placing step, a tension member 300 installing step, and a post tension introducing step.

The method of manufacturing a prestressed girder according to the present invention is characterized in that a pair of end segments 100 manufactured in the step of manufacturing the end segments 100 and the center segments 200 manufactured in the step of manufacturing the center segments 200 are assembled The method comprising: a segmenting step of disposing the end segment (100) at both ends of the central segment (200), and a step of disposing the end segment (100) over the end segment (100) A step 300 of inserting a tension member 310 of the member 300 and arranging a fixing member 330 of the tension member 300 installed at both ends of the tension member 310, The tension member 310 installed in the first sheath pipe 130 and the second sheath pipe 230 is tensed to introduce the fixing member 330 into the end segment 100 ) Agent may comprise a tension introductory phase.

4, the tendon member 300 is inserted into the first sheath pipe 130 and the second sheath pipe 230 to form a tension member (not shown) that provides the post tension force F1 310 and a mounting member for fixing the tension member 310 to both end portions of the end segment 100 provided with the central segment 200 therebetween.

4, an end segment 100 is disposed at both ends of the central segment 200, and a second sheath tube 230 disposed at the middle segment 200 and a first sheath (not shown) of the end segment 100 are provided, The tension member 310 is inserted into the tube 130 and the tension member 310 is tensioned by the tension device in a state where the fixing member 330 for fixing the tension member 310 is disposed at both ends of the end segment 100. [ The fixing member 330 can be fixed in a state in which the post tension force F1 is introduced.

That is, a pair of end segments 100 and a central segment 200 can be connected while being fixed to one end of each end segment 100 at both ends of the tension member 310.

A grout member may be installed in the first sheath pipe 130 and the second sheath pipe 230 for the complete attachment of the first concrete member 110 and the second concrete member 210.

In this manner, the prestressed girders including the connected end segments 100 and the central segment 200 are continuously installed at the first point D1 and the second point D2 of the bridge, A prestressed bridge can be formed.

4, before the post tension introduction step, a joint paint is applied between the end segment 100 and the central segment 200 between the segment placement step and the post tension introduction step, And a step of forming a bonding paint layer (400).

The step of forming the bonding paint layer 400 includes the steps of applying a bonding paint to the connecting portion of the end segment 100 and the central portion 200 to which the end portion 100 and the center portion 200 are connected, And curing in a state in which the bonding paint layer 400 is formed.

The tension member 310 inserted into the first sheath pipe 130 and the second sheath pipe 230 is tensioned in a state where the bonding paint layer 400 is cured and the post tension force F1 is introduced The fusing member 330 may be fixed to the end segment 100.

As the bonding paint, a material such as epoxy can be utilized. However, it is needless to say that various bonding paints can be used.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. And will be apparent to those skilled in the art.

1: girder 1-1: girder staging
1-2: girder bottom 2: tension member
100: end segment 110: first concrete member
130: first sheath tube 200: central segment
210: second concrete member 230: second sheath pipe
250: Strand 300: Tension member
310: tension member 330: fixing member
400: bonding paint layer D1: first point
D2: second point E: bending stress due to design load
F: Prestress force F1: Post tension force
F2: Pretension force G: Pristress force introduced in the past
L1: length of end segment L2: length of center segment
P1: Maximum tensile stress of girder bottom 1 P2: Maximum tensile stress of girder bottom 2
S1: Post tension section S2: Pretension section
X1: Over design area X2: Tension area
X3: redundant compression generation area X4: introduction stress reduction area

Claims (11)

A first concrete member, a pair of end segments embedded in the first concrete member and having a first sheath tube formed in a predetermined direction;
A second concrete member, a plurality of stranded wires installed in a straight line and embedded in the second concrete member to introduce a pre-tension force, and a plurality of stranded wires connected to the first sheath pipe, A center segment having a second sheath tube formed in a predetermined direction embedded in the center segment; And
And a tension member installed through the end segment and the central segment and introducing a post tension force in a predetermined direction to connect the pair of end segments to the center segment,
The post tension force introduced into the end segment by the tendon member is set so as to exceed a maximum tensile stress of a girder lower edge having a maximum value at a connection portion between the end segment and the center segment and to be within an allowable stress,
The pretensioning force introduced into the central segment by the plurality of strands is characterized by compressive stress introduced into the central segment by the tensile member at a maximum tensile stress of the girder lower edge having a maximum value at the center of the center segment, Is set so as to exceed a value obtained by subtracting a post tension force introduced and to be within an allowable stress.
The method according to claim 1,
The second sheath pipe is installed in a central region of a cross section in the width direction of the second concrete member,
And the strand is disposed below the second concrete member in the width direction and symmetrically disposed in the width direction about the second sheath pipe.
3. The method of claim 2,
Wherein the tendon member and the second sheath tube are formed such that a center thereof is curved downward,
Wherein the strand is disposed at a lower curvature point of the second sheath tube lower than a top end height of the second sheath tube.
A first concrete member, a pair of end segments embedded in the first concrete member and having a first sheath tube formed in a predetermined direction;
A second concrete member, a plurality of stranded wires installed in a straight line and embedded in the second concrete member to introduce a pre-tension force, and a plurality of stranded wires connected to the first sheath pipe, A center segment having a second sheath tube formed in a predetermined direction embedded in the center segment; And
And a tension member installed through the end segment and the central segment to introduce a post tension force in a predetermined direction to connect the pair of end segments to the center segment,
Wherein the length of the end segment is determined such that the post tension force introduced by the tendon member at the total span of the prestressed girder is greater than a maximum design external force applied to the end segment and the generated stress is within an allowable stress, Span determining step; And
The sum of the magnitude of the post tension force introduced by the tendon member determined in the end span determining step and the magnitude of the pre-seating force introduced in the central segment exceeds the maximum design external force applied to the central segment, Determining a length of the center segment so that the length of the central segment becomes
The end span determining step may include:
The post tension force introduced into the end segment by the tendon member is set so as to exceed a maximum tensile stress of a girder lower edge having a maximum value at a connection portion between the end segment and the center segment and to be within an allowable stress,
Wherein the center span determining step includes:
Wherein the pre-tension force introduced by the plurality of stranded wires comprises a post tension that is introduced by the compressive stress introduced into the central segment by the tensile member at a maximum tensile stress of the girder lower edge having a maximum value at the center of the center segment, Wherein the predetermined value is set so as to exceed a value obtained by subtracting the force and be within an allowable stress.
delete delete 5. The method of claim 4,
An end segment manufacturing step of fabricating the end segment according to the post tension force determined in the end span determining step and the length of the end segment;
A center segment forming step of fabricating the center segment according to the pre-tension force determined in the center span determining step and the length of the center segment;
And joining the first sheath tube and the second sheath tube in a state where the end segments are disposed at both ends of the center segment, and introducing a post tension force in a state in which the tendon members are disposed. A method of manufacturing a rest girder.
8. The method of claim 7,
Wherein a plurality of stranded wires installed in the central segment are installed in the entire length of the center segment without any non-attached section with the second concrete member, and pre-tensioning is introduced.
8. The method according to claim 7, wherein the step of fabricating the end segments and the step of fabricating the center segments comprise:
Wherein the end segment and the center segment are fabricated such that the second concrete member of the center segment has a strength equal to or greater than that of the first concrete member of the end segment.
8. The method of claim 7,
A segment transporting step of transporting the pair of end segments fabricated in the end segment manufacturing step and the center segment fabricated in the manufacturing step of the center segment to a construction site;
A segment arrangement step of arranging the end segments at both ends of the central segment;
A tension member mounting step of inserting a tension member of the tension member over the end segment and the central segment and disposing the fixing member of the tension member provided at both ends of the tension member; And
And a post tensioning step of tensioning the tension member inserted in the first sheath pipe and the second sheath pipe to fix the fixing member to the end segment in a state in which the post tension force is introduced, Gt;
11. The method of claim 10, wherein, prior to the step of introducing post tension,
And a joint paint layer forming step of applying and curing a joint paint to a joint portion between the end segment and the center segment between the segment placement step and the post tension introduction step.
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