WO2021107249A1

WO2021107249A1 - Method for manufacturing prestressed girder for improvement of transverse curvature, and method for constructing girder bridge thereby

Info

Publication number: WO2021107249A1
Application number: PCT/KR2019/017603
Authority: WO
Inventors: 구민세; 구호원
Original assignee: 주식회사 엠에스
Priority date: 2019-11-28
Filing date: 2019-12-12
Publication date: 2021-06-03
Also published as: KR102167843B1

Abstract

Disclosed are a method for manufacturing a prestressed girder for improving transverse curvature that can minimize the occurrence of transverse curvature when introducing prestress to a girder, and a method for constructing a girder bridge thereby. To this end, provided is a method for manufacturing a prestressed girder for improving transverse curvature and, more particularly, a method for manufacturing a girder with two side steel strands arranged on the left and right sides of the vertical neutral axis of the girder, the method comprising: a beam manufacturing step of manufacturing a beam by installing two or more anchorages to which the side steel strands are to be connected; a step of introducing a first prestressing force for prestressing the first side steel strand with the first prestressing force which is weaker than a design prestressing force; a step of introducing a second prestressing force for prestressing the second side steel strand with the second prestressing force which is equal to or weaker than the design prestressing force and exceeds the first prestressing force; and a step of introducing a third prestressing force for prestressing the first side steel strand again with the third prestressing force that overlaps with the first prestressing force and is equal to or weaker than the design prestressing force and is equal to or greater than the second prestressing force. According to the present invention, instead of increasing the cross-sectional area of the prestressed girder or installing a separate steel material, it is possible to suppress the occurrence of eccentricity that causes transverse curvature of the girder by only prestressing some steel strands twice or more than twice, thereby minimizing a difference between the left and right gaps of the prestressed girder.

Description

Manufacturing method of prestressed girder for improvement of transverse curvature and construction method of girder bridge using the same

The present invention relates to a manufacturing method of a prestressed girder in which some strands are divided into two or more tensions to improve lateral curvature, and a method for constructing a girder bridge using the same, and more particularly, transverse curvature occurs when prestress is introduced into the girder. It relates to a method of manufacturing a prestressed girder for improvement of lateral curvature that can minimize lateral curvature and a construction method of a girder bridge using the same.

For the upper structure of the girder bridge, a girder using a tension strand has been developed and used to prevent deformation or deflection of the structure due to load.

That is, it is possible to reduce the deflection of the structure due to the load by applying a force to both ends of the strand to tension the strand, and to prevent the structure from being destroyed by excessive tensile stress applied to the structure by an external load.

For example, a girder (hereinafter, abbreviated as "PS girder") that introduces a compressive stress by such a stranded wire is classified according to the composition of the material constituting the girder. Specifically, the PS girder is a prestressed concrete girder (PSC girder) composed of only concrete without a steel I-girder, and a prestressed steel with a steel I-girder having a predetermined stiffness inside the concrete section. It is classified as a Prestressed Steel Composite Girder.

More specifically, the PS girder refers to a beam in which a compressive stress (prestress) is introduced in advance through a tension member disposed inside the cross section in order to offset the tensile stress occurring in the concrete by its own weight and external load.

1 is a front view showing a domestic standard cross-section PSC beam used as a bridge girder. And FIG. 2 is a cross-sectional view showing the arrangement of the tension member in the central portion of the PSC beam of FIG.

In general, the tension member is fixed at the end of the beam and a large concentrated load is applied, so a large concrete cross section is required. Therefore, as shown in Fig. 1, since a large acupressure stress is generated at the anchoring position, anchoring tools are vertically arranged in a line on the cross section of the concrete beam. This is to secure a large anchoring cross-section capable of resisting acupressure stress, and to respond to an external force moment generated in a parabolic shape. On the other hand, in the central part of the PSC beam, as shown in FIG. 2, in order to maximize the eccentric effect, the tension member is disposed at the lower part of the section as far away from the horizontal neutral axis (HNA) as possible through the center of the concrete section. Therefore, when each tension member is sequentially tensioned, the

tension members

13 and 14 arranged eccentrically on the vertical neutral axis (VNA) generate an eccentric load, and thus have a structural defect in which transverse curvature occurs.

That is, when the first tension member 11 and the second tension member 12 are tensioned, since the tension member is located on the vertical neutral axis (VNA), lateral curvature hardly occurs.

However, when tensioning the third tension member 13, since the tension member is disposed so as to deviate from the vertical neutral axis (VNA), transverse curvature is inevitably generated in proportion to the magnitude of tension and eccentricity. And finally, when the fourth tension member 14 is tensioned, since a tension force corresponding to the third tension member 13 is introduced, the transverse bending displacement generated by the third tension member 13 is recovered, and the vertical neutral axis (VNA) is restored to its original state. Returning to the position is the manufacturing principle of the PSC beam.

However, theoretically, it can be expected that the transverse bending displacement will be recovered by tensioning any one tension member symmetrically arranged with respect to the vertical neutral axis (VNA) and tensioning the tension member symmetrical with it. However, in actual construction, even if the tension member symmetrical with the tension member is tensioned after the transverse bending displacement is generated by any one of the tension members, the vertical neutral axis does not return to its original position and the horizontal curve remains permanently. This means that even if the 3rd and 4th tension members are tensioned with the same force, the 3rd tension member is tensioned in the state before transverse curvature occurs in the beam, whereas the 4th tension member is in a state where the initial condition of the transverse curvature in the beam is different. because it's tense.

In addition, when the first tension member 13 symmetrically disposed with respect to the vertical neutral axis VNA and the second tension member 14 symmetrical to the first tension member are tensioned at once, the occurrence of lateral curvature may be fundamentally blocked. However, it is difficult to simultaneously tension the first tension member and the second tension member in view of the weight and size of the tensioning jack for tensioning the tension member.

Accordingly, the transverse stiffness of the beam (the stiffness of the beam resisting transverse bending) must be increased to prevent transverse bending or to fabricate the PS beam within an allowable transverse displacement. However, if the cross-section is enlarged, its own weight is greatly increased, which tends to become uneconomical. Therefore, there is a need for a method capable of minimizing lateral curvature while increasing the stiffness of the cross section to a minimum.

In particular, the recently improved PS beam minimizes its own weight and selects the optimal cross-section that maximizes the flexural rigidity, so the cross-section is very small and the height is low, so the lateral rigidity is very small. Nevertheless, since it is applied to bridges between long spans, lateral bending occurs frequently when tension is introduced in the field, and design reviews for this are not made. Therefore, the reality is that there is a high risk of damage and safety accidents, as well as a decrease in the load-bearing capacity of the bridge and the occurrence of a collapse accident during construction or construction of beams due to transverse bending.

Therefore, the first object of the present invention is to effectively suppress the transverse curvature of the girder that occurs when the prestress is introduced. Therefore, the prestressed girder is manufactured by dividing the tension of the left and right strands causing eccentricity to improve the transverse curvature. is to provide a way.

In addition, a second object of the present invention is to provide a method of constructing a girder bridge using a method of manufacturing a prestressed girder for improving transverse curvature so as to secure stability against transverse curvature during construction of the girder bridge.

In order to achieve the first object of the present invention described above, in an embodiment of the present invention, in a method for tensioning a girder in which two or more side strands disposed on the left and right of a girder vertical neutral axis (VNA) are installed, the side strands are to be connected A beam production step of manufacturing a beam by installing two or more anchorages, a first tension force introduction step of tensioning the first side stranded wire with a first tension force that is less than the design tension force, and a first tension force that exceeds the first tension force and is less than the design tension force A secondary tension force introduction step of tensioning the second side strand with a second tension force, and a tertiary tension of re-tensioning the first side strand with a third tension that is overlapped with the first tension force and is equal to or greater than the second tension force and less than or equal to the design tension force It provides a method of manufacturing a prestressed girder for improving lateral curvature, including an introduction step.

In addition, in order to achieve the second object of the present invention, an embodiment of the present invention provides a construction method of a girder bridge using the manufacturing method of the prestressed girder for improving the lateral curvature described above.

According to the present invention, it is possible to suppress the occurrence of eccentricity that causes lateral curvature of the girder only by dividing and straining some strands twice or more, thereby minimizing the gap between the left and right of the PS girder.

In addition, in the present invention, the initial strand can be used as it is because the strand is tensioned multiple times at a level that is not damaged.

In addition, the present invention makes it possible to manufacture a high-quality PS girder that minimizes the amount of lateral curvature, which is a problem, especially when lengthening the span.

1 is a front view showing a domestic standard cross-section PSC beam used as a bridge girder.

Figure 2 is a cross-sectional view showing the arrangement of the tension member in the central portion of the PSC beam of Figure 1;

3 is a flowchart for explaining a method of manufacturing a PS girder according to the present invention.

Figure 4 is a perspective view for explaining the PS girder according to the present invention.

5 is a cross-sectional view showing a first embodiment of the PS girder according to the present invention.

6 is a cross-sectional view showing a second embodiment of the PS girder according to the present invention.

7 is a cross-sectional view showing a third embodiment of the PS girder according to the present invention.

8 is a cross-sectional view showing the arrangement of the tension member in the central part of the PS girder of FIG.

9 is a cross-sectional view showing a fourth embodiment of the PS girder according to the present invention.

10 is a cross-sectional view showing a fifth embodiment of the PS girder according to the present invention.

11 is a cross-sectional view showing a sixth embodiment of the PS girder according to the present invention.

12 is a cross-sectional view showing a seventh embodiment of the PS girder according to the present invention.

13 is a cross-sectional view showing an eighth embodiment of the PS girder according to the present invention.

14 is a plan view showing a PS girder provided with a concrete protrusion according to the present invention.

15 is a cross-sectional view showing a PS girder provided with a concrete protrusion according to the present invention.

16 is a schematic diagram for explaining the compressive force generated during tension of the strand installed on the existing PS girder.

17 is a schematic view for explaining the compressive force generated during tension of the strand installed on the PS girder according to the present invention.

18 is a flowchart for explaining the construction method of the girder bridge according to the first embodiment of the present invention.

19 is a flowchart for explaining the construction method of the girder bridge according to the first embodiment of the present invention.

20 is a flowchart for explaining the construction method of the girder bridge according to the second embodiment of the present invention.

21 is a flowchart for explaining the construction method of the girder bridge according to the second embodiment of the present invention.

22 is a flowchart for explaining the construction method of the girder bridge according to the third embodiment of the present invention.

23 is a flowchart for explaining the construction method of the girder bridge according to the third embodiment of the present invention.

Hereinafter, a method of manufacturing a prestressed girder (hereinafter, abbreviated as 'PS girder manufacturing method') for improving lateral curvature according to preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart for explaining a method of manufacturing a PS girder according to the present invention, FIG. 4 is a perspective view for explaining a PS girder according to the present invention, and FIG. 5 is a first embodiment of a PS girder according to the present invention It is a cross-sectional view showing

4 and 5, the method of manufacturing a PS girder according to the present invention is 2 on the left and right sides of the vertical neutral axis so as to deviate from the vertical neutral axis (VNA) with respect to the vertical neutral axis (VNA) of the girder, respectively. A girder with side strands installed is used.

At this time, the girder may be configured to include an upper flange and an abdomen connected to the lower portion of the upper flange. And the girder may be configured to include an upper flange and a lower flange and an abdomen connecting the upper flange and the lower flange.

Here, the abdomen connected to the lower part of the upper flange may be formed to have a reduced left and right width than the upper flange. And the abdomen connecting the upper flange and the lower flange may be formed to have a reduced left and right width than the upper flange and the lower flange.

If necessary, the girder has a first central strand 111 installed so as to be positioned on a vertical neutral axis between the first side strand 112 and the second side strand 113, and a vertical lower portion of the first central strand 111. The second central strand 114 installed to be positioned on the neutral axis, the third side strand 115 installed to be positioned in a diagonal direction of the second side strand 113 with respect to the vertical neutral axis, and the first side with respect to the vertical neutral axis The fourth side strand 116 installed to be positioned in the diagonal direction of the strand 112, the third central strand 117 installed to be positioned on the vertical neutral axis of the lower part of the second central strand 114, and the second central strand 117 based on the vertical neutral axis The fifth side strand 118 installed to be positioned in the diagonal direction of the 4 side strand 116 and the sixth side strand 119 installed to be positioned in the diagonal direction of the third side strand 115 with respect to the vertical neutral axis are optional may be further included.

The central strand installed on the vertical neutral axis of the girder or the side strand installed outside the vertical neutral axis may be installed so as to be directly embedded in the concrete. In addition, the side strands may be placed inside the concrete through a sheath duct, and after being tensioned, they may be embedded through an attachment mortar or an adhesive mortar in the interior of the sheath pipe.

On the other hand, the manufacturing method of the girder according to the present invention, as shown in Fig. 3, the beam manufacturing step (S1), the first tension force introduction step (S10), the second tension force introduction step (S20), and the third tension force introduction Step S30 is included.

In the beam manufacturing step (S1), two or more anchorages to which side strands are connected in the left and right directions of the vertical neutral axis are installed on one surface of the girder. In the first tension force introduction step (S10), the first side strand 112 is tensioned with a first tension force less than the design tension force. In the second tension force introduction step (S20), the second side strand 113 positioned in the opposite direction to the first side strand 112 with respect to the vertical neutral axis exceeds the first tension force and is less than or equal to the design tension. tense with In the third tension force introduction step (S30), the first side strand 112 is tensioned again with a third tension force that is overlapped with the first tension force and is less than the design tension force while exceeding the second tension force.

Here, the girder means a girder capable of introducing a compressive stress using the tension of the stranded wire. And the PS girder 100 means a girder in which a compressive stress is introduced using the tension of a strand. In this case, the side strands and the central strands may be provided in the entire section of the girder.

To this end, the anchorage installed at the distal end of the side strand and the central strand to fix the side strand and the central strand to the girder is preferably installed at the end of the girder.

Hereinafter, each component will be described in more detail with reference to the drawings.

The manufacturing method of the PS girder according to the present invention includes a beam manufacturing step (S1).

The beam manufacturing step (S1) is a fixture to be connected to the first side strand 112 and the second side strand 113 so that the first side strand 112 and the second side strand 113 can be fixed to the end of the girder. is installed at the end of the girder.

In the beam manufacturing step (S1), when the first central strand 111 installed to be positioned on the vertical neutral axis of the girder is provided, an anchorage to be connected to the first central strand 111 is also installed at the end of the girder.

In the beam manufacturing step (S1), the first central strand 111, the second central strand 114, the third side strand 115, the fourth side strand 116, the third central strand 117, and the fifth When the side strands 118 and the sixth side strands 119 are installed on the girder, an anchorage to which each strand will be connected is installed at the end of the girder.

At this time, the center of the anchorage to which the strand will be connected is installed to almost coincide with the Horizontal Neutral Axis (HNA) of the cross section of the beam, and the error range is 16.67% to prevent tensile stress from occurring at the top and bottom of the end. Here, the neutral axis means a straight line connecting the points where the normal stress generated in the cross section becomes 0 when the bending moment acts on the girder.

More specifically, the end stress f = (-P/A)+(Mc/I) acting on the beam.

Here, A (cross-sectional area) is b (left and right length of beam cross-section) × h (up-and-down length of beam cross-section), M (moment due to P) is P (tension) × e (eccentric distance), c is h ( The vertical length of the beam cross-section)/2, and I (second moment of cross-section) is bh ³ /12.

Accordingly, since the stress limit of the end stress (f) acting on the beam must be 0 or less, the eccentric distance is formed to be 0.1667h or less according to the following [Equation 1].

Then, the manufacturing method of the PS girder according to the present invention may further include a first central strand tension step (S5) after the beam fabrication step (S1).

The first central strand tension step (S5) is a step of tensioning the first central strand 111 located on the vertical neutral axis between the first side strand 112 and the second side strand 113 with a preset design tension.

In this step (S5), since the first central strand 111 is located on the vertical neutral axis, even if it is tensioned, lateral curvature does not occur, so the first central strand 111 is tensioned using a jack for tension.

Then, the manufacturing method of the PS girder according to the present invention includes a first tension force introduction step (S10).

The first tension force introduction step (S10) is a step of tensioning the first side strand 112 with a first tension force that is less than the design tension force. In this step (S10), the first side strand 112 is tensioned to a level where the number of tensions of the first side strand 112 is reduced while reducing the difference in the eccentric moment between the left and right sides of the girder based on the vertical neutral axis of the girder. At this time, the first side strand 112 can be tensioned using a jack for tension.

In this step (S10), it is possible to tension the first side strand 112 with a tension of 40% to 60% of the desired design tension. This tension is to minimize the transverse bending displacement occurring on one side of the girder with respect to the vertical neutral axis and to reduce the number of tensions of the first side strand 112 . For example, in the first tension force introduction step (S10), when the design tension of the first side strand 112 is 200 tons, a tension of 80 tons to 120 tons is introduced into the first side strand 112 through a jack for tension. However, the present invention is not limited thereto.

Then, the manufacturing method of the PS girder according to the present invention includes a secondary tension force introduction step (S20).

The second tension force introduction step (S20) is a step of introducing a second tension force exceeding the first tension force to the second side strand 113. In this step (S20), while recovering the transverse displacement generated by the first side strand 112, the transverse displacement generated on the other side of the girder with respect to the vertical neutral axis is minimized.

To this end, in this step (S20), the second side strand 113 is tensioned with a second tension force that is less than the design tension while exceeding the first tension force. At this time, the second side strand 113 can be tensioned using a jack for tension.

As a specific aspect, in the second tension force introduction step (S20) according to the present invention, the second side strand 113 may be tensioned with a tension of 75% to 100% of the desired design tension. For example, when the design tension of the second side strand 113 is 200 tons in the second tension force introduction step (S20), a tension force of 200 tons is introduced into the second side strand 113 through a tension jack.

In this way, if the second side strand 113 is tensioned to 100% of the design tension in this step (S20), the tension of the second side strand 113 becomes unnecessary in the future. The number of tensions is minimized to 1 total. And when the second side strand 113 is tensioned to a design tension of less than 100%, a step of additionally tensioning the second side strand 113 after the third tension force introduction step (S30) is required, but it occurs on the other side of the girder The resulting lateral curvature displacement is reduced. At this time, the step of additionally straining is a process for introducing a total design tension of 100% to the second side strand 113 .

Then, the manufacturing method of the PS girder according to the present invention includes a third tension force introduction step (S30).

The third tension force introduction step (S30) is a step of introducing a third tension force that is superimposed on the first tension force on the first side strand 112 and is greater than or equal to the second tension force and less than or equal to the design tension force. In this step (S30), while recovering the transverse displacement generated by the second side strand 113, the transverse displacement generated on one side of the girder with respect to the vertical neutral axis is minimized.

In other words, as for the third tension force, a value combined with the first tension force is equal to or less than the design tension force, and is greater than or equal to a value obtained by subtracting the first tension force from the second tension force.

Specifically, in this step (S30), it is possible to tension the first side strand 112 to a tension of 40% to 60% of the desired design tension.

As a specific aspect, the present invention tensions the first side strand 112 with 50% of the design tension in the first tension force introduction step (S10), and 100% tension in the second tension force introduction step (S20). It is preferable to tension the two side strands 113 . Then, in the present invention, it is preferable to tension the first side strand 112 with the remaining 50% of the design tension in the third tension force introduction step (S30). This is because, since the process of tensioning the first side strand 112 and the second side strand 113 is minimized, the manufacturing time of the prestressed girder is reduced.

For example, in the third tension force introduction step (S30), the design tension of the first side strand 112 and the second side strand 113 is 200 tons, the first tension force is 100 tons, and the second tension force is 200 tons. , 100 tons can be introduced as the third tension force. That is, if the third tension force is 100 tons, it overlaps with the first tension force 100 tons and is 200 tons, so that the condition of not less than the second tension force and less than the design tension force is satisfied.

In this way, in the first tension force introduction step (S10), the first side strand 112 is tensioned to 50% of the design tension, and then, in the third tension force introduction step (S30), the first side strand 112 is 50% of the If it is tensioned with the design tension, tension of the first side strand 112 becomes unnecessary in the future. Accordingly, the number of tensions of the first side strand 112 is reduced to two.

Referring to FIG. 6 , the second central strand tensioning step S35 is a step of tensioning the second central strand 114 located on the vertical neutral axis under the first central strand 111 with a preset design tension.

In this step (S35), since the second central strand 114 is located on the vertical neutral axis, no lateral curvature occurs even when tensioned, the second central strand 114 is tensioned using a jack for tension. For example, in the second central strand tension step ( S35 ), if the design tension of the second central strand 114 is 200 tons, a tension force of 200 tons is introduced into the second central strand 114 .

This second central strand tension step (S35) may be performed after tensioning the first side strand 112 through the third tension force introduction step (S30) as shown in FIG. 6 . And the second central strand tension step (S35) may proceed between the first central strand tension step (S5) and the first tension force introduction step (S10).

Figure 7 is a cross-sectional view showing a third embodiment of the PS girder according to the present invention, Figure 8 is a cross-sectional view showing the arrangement of the tension member in the central part of the PS girder of FIG. 9 is a cross-sectional view showing a fourth embodiment of the PS girder according to the present invention.

7 to 9, the method of manufacturing a PS girder according to the present invention further includes a fourth tension force introduction step (S40) after the third tension force introduction step (S30) or the second central strand tension step (S35) can do.

The fourth tension force introduction step (S40) is a step of tensioning the third side strand 115 located in the diagonal direction of the first side strand 112 with respect to the vertical neutral axis to a fourth tension force that is less than the design tension. In this step (S40), the third side strand 115 is tensioned to a level where the number of tensions of the third side strand 115 is reduced while reducing the difference in the eccentric moment between the left and right sides of the girder based on the vertical neutral axis of the girder. At this time, the third side strand 115 may be tensioned using a jack for tension.

In addition, in this step (S40), it is possible to tension the third side strand 115 to a tension of 40% to 60% of the desired design tension. This is to minimize the transverse bending displacement occurring on the other side of the girder with respect to the vertical neutral axis and to reduce the number of tensions of the third side strand 115 . For example, in this step (S40), when the design tension of the third side stranded wire 115 is 200 tons, a tension of 80 to 120 tons can be introduced to the third side stranded wire 115 through the tension jack, but this not limited

7 to 9 , the method for manufacturing a PS girder according to the present invention may further include a fifth tension force introduction step (S50).

The fifth tension force introduction step (S50) is a step of introducing a fifth tension force exceeding the fourth tension force to the fourth side strand 116 located in the diagonal direction of the second side strand 113 with respect to the vertical neutral axis. to be. In this step (S50), while recovering the transverse displacement generated by the third side strand 115, the transverse displacement generated on the other side of the girder with respect to the vertical neutral axis is minimized.

To this end, in this step (S50), the fourth side strand 116 is tensioned with a fifth tension force that is less than the design tension while exceeding the fourth tension. At this time, the fourth side strand 116 can be tensioned using a jack for tension.

As a specific aspect, in the fifth tension force introduction step (S50) according to the present invention, the fourth side strand 116 may be tensioned with a tension of 75% to 100% of the desired design tension. For example, in the fifth tension introduction step (S50), when the design tension of the fourth side strand 116 is 200 tons, a tension of 200 tons is introduced into the fourth side strand 116 through a tension jack.

In this way, if the fourth side strand 116 is tensioned to 100% of the design tension in the fifth tension force introduction step (S50), the tension of the fourth side strand 116 becomes unnecessary later, so the fourth side strand ( 116) is minimized to one total number of tensions.

And if the fourth side strand 116 is tensioned to a design tension of less than 100%, a step of additionally tensioning the fourth side strand 116 is required after the 6th tension introduction step (S60), but on the other side of the girder The resulting lateral curvature displacement is reduced. At this time, the step of additionally straining is a process for introducing a total design tension of 100% to the fourth side strand 116 .

7 to 9 , the method of manufacturing a PS girder according to the present invention may further include a sixth tension force introduction step (S60).

The sixth tension force introduction step (S60) is a step of introducing a sixth tension force that is superimposed on the fourth tension force on the third side strand 115 and is equal to or greater than the fifth tension force and less than or equal to the design tension force. In this step (S60), while recovering the transverse displacement generated by the fourth side strand 116, the transverse displacement generated on one side of the girder with respect to the vertical neutral axis is minimized.

In other words, as for the sixth tension force, the value combined with the fourth tension force is equal to or less than the design tension force, and is greater than or equal to the value obtained by subtracting the fourth tension force from the fifth tension force.

Specifically, in the sixth tension force introduction step (S60) according to the present invention, the third side strand 115 may be tensioned with a tension of 40% to 60% of the desired design tension, but is not limited thereto.

As a specific aspect, the present invention tensions the third side strand 115 with a tension of 50% of the design tension in the fourth tension force introduction step (S40), and in the fifth tension force introduction step (S50), 100% tension. It is desirable to tension the four side strands 116 . Subsequently, in the present invention, it is preferable to tension the third side strand 115 with the remaining 50% of the design tension in the sixth tension force introduction step (S60). This is to provide the effect that the manufacturing time of the prestressed girder is shortened since the process of tensioning the third side strand 115 and the fourth side strand 116 is minimized.

For example, in the sixth tension introduction step (S60), the design tension of the third side strand 115 and the fourth side strand 116 is 200 tons, the fourth tension is 100 tons, and the fifth tension is 200 tons. , 100 tons can be introduced as the sixth tension force. That is, if the sixth tension force is 100 tons, the fourth tension force is overlapped with 100 tons and is 200 tons, so the condition of being equal to or greater than the fifth tension force and less than the design tension force is satisfied.

In this way, if the third side strand 115 is tensioned to 50% of the design tension in the sixth tension force introduction step (S60), the tension of the third side strand 115 becomes unnecessary later, so the third side strand ( 115) is reduced to 2 times.

Referring to FIG. 10 , the method of manufacturing a PS girder according to the present invention may further include a third central strand tension step (S65) after the sixth tension force introduction step (S60).

The third central strand tension step (S65) is a step of tensioning the third central strand 117 positioned on the vertical neutral axis under the second central strand 114 with a preset design tension.

In this step (S65), since the third central strand 117 is located on the vertical neutral axis, lateral curvature does not occur even when tensioned, so the third central strand 117 is connected to the side strands adjacent to the third row using a jack for tension. tense no matter what. For example, in the tensioning step of the third central strand 117 , if the design tension of the third central strand 117 is 200 tons, a tension of 200 tons is introduced into the third central strand 117 .

Referring to FIG. 11 , the method of manufacturing a PS girder according to the present invention may further include a seventh tension force introduction step (S70) after the sixth tension force introduction step (S60) or the third central strand tension step (S65). .

The seventh tension force introduction step (S70) is a step of tensioning the fifth side strand 118 with a seventh tension force that is less than the design tension force. In this step (S70), the fifth side strand 118 is tensioned to a level where the number of tensions of the fifth side strand 118 is reduced while reducing the difference in the eccentric moment between the left and right sides of the girder with respect to the vertical neutral axis of the girder. At this time, the fifth side strand 118 can be tensioned using a jack for tension.

In the seventh tension introduction step (S70) according to the present invention, the fifth side strand 118 may be tensioned with a tension of 40% to 60% of the desired design tension, but is not limited thereto. This is to minimize the transverse bending displacement occurring on one side of the girder with respect to the vertical neutral axis and to reduce the number of tensions of the fifth side strand 118 . For example, when the design tension of the fifth side strand 118 is 200 tons in the seventh tension introduction step (S70), a tension of 80 tons to 120 tons is introduced into the fifth side strand 118 through a tension jack. can

Referring to FIG. 11 , the method of manufacturing a PS girder according to the present invention may further include an 8th tension force introduction step (S80) after the 7th tension force introduction step (S70).

The eighth tension force introduction step (S80) is a step of introducing an eighth tension force exceeding the seventh tension force to the sixth side strand 119. In this step (S80), while recovering the transverse displacement generated by the fifth side strand 118, the transverse displacement generated on the other side of the girder with respect to the vertical neutral axis is minimized.

To this end, in this step (S80), the sixth side strand 119 is tensioned with the eighth tension force that is less than the design tension while exceeding the seventh tension. At this time, the sixth side strand 119 can be tensioned using a jack for tension.

As a specific aspect, in the eighth tension force introduction step (S80) according to the present invention, the sixth side strand 119 may be tensioned with a tension of 75% to 100% of the desired design tension. For example, in the eighth tension introduction step (S80), when the design tension of the sixth side strand 119 is 200 tons, a tension force of 200 tons is introduced into the sixth side strand 119 through a tension jack.

As such, if the sixth side strand 119 is tensioned to 100% of the design tension in the 8th tension force introduction step (S80), the tension of the sixth side strand 119 becomes unnecessary later, so the sixth side strand ( 119) is minimized to 1 total. And if the sixth side strand 119 is tensioned to a design tension of less than 100%, a step of additionally tensioning the sixth side strand 119 is required after the ninth tension introduction step (S90), but on the other side of the girder The resulting lateral curvature displacement is reduced. At this time, the step of additionally straining is a process for introducing a total design tension of 100% to the sixth side strand 119 .

Referring to FIG. 11 , the method of manufacturing a PS girder according to the present invention may further include a ninth tension introduction step (S90) after the eighth tension force introduction step (S80).

The ninth tension force introduction step (S90) is a step of introducing a ninth tension force that overlaps the seventh tension force and is equal to or greater than the eighth tension force and less than or equal to the design tension force to the fifth side strand 118. In this step (S90), while recovering the transverse displacement generated by the sixth side strand 119, the transverse displacement generated on one side of the girder with respect to the vertical neutral axis is minimized.

In other words, as for the ninth tension force, a value combined with the seventh tension force is equal to or less than the design tension force, and is greater than or equal to a value obtained by subtracting the seventh tension force from the eighth tension force.

Specifically, in the ninth tension introduction step (S90) according to the present invention, the fifth side strand 118 may be tensioned with a tension of 40% to 60% of the desired design tension, but is not limited thereto.

As a specific aspect, the present invention tensions the fifth side strand 118 with a tension of 50% of the design tension in the 7th tension force introduction step (S70), and 100% tension in the 8th tension force introduction step (S80). It is desirable to tension the 6 side strands 119 . Next, in the present invention, it is preferable to tension the fifth side strand 118 with the remaining 50% of the design tension in the ninth tension force introduction step (S90).

As an embodiment, when the length of the girder according to the present invention is 40 m or less, for example, 20 m to 40 m, the first to

fourth side strands

112, 113, 115, and 116 are preferably tensioned at the ends in the same direction. This is the minimum that must be introduced to the entire girder even if the loss of tension force occurs overlappingly along the longitudinal direction of the girder when the tension force is introduced to all strands with 100% design tension at one end of the girder when the length of the girder is 40m or less. This is because a compressive force greater than the compressive force is introduced to the other end of the girder.

As another embodiment, if the length of the girder according to the present invention exceeds 40m, for example, 40m to 60m, the first side strand 112 and the second side strand 113 are preferably tensioned at one end of the girder. Then, the third side strand 115 and the fourth side strand 116 are preferably tensioned at the other end of the girder opposite to the one end. This is a problem that, when the length of the girder exceeds 40m, when the tension force is introduced to all strands at 100% of the design tension at one end of the girder, a compressive force less than the minimum compressive force that must be introduced to the entire girder at the other end of the girder is introduced. because it may occur. However, if the first and

second side strands

112 and 113 and the third and

fourth side strands

115 and 116 are in opposite directions to each other, when the tension force is introduced at the end of the girder with 100% of the design tension, the compressive force greater than the desired value in the entire girder. This is introduced This is because the tension of the first and

second side strands

112 and 113 and the tension of the third and

fourth side strands

115 and 116 complement each other.

More specifically, in FIG. 10, when the length of the girder exceeds 40 m, the first central strand 111, the first side strand 112, and the second side strand 113 are tensioned at one end of the girder and the second central strand ( 114), the third side strand 115, the fourth side strand 116, and the third central strand 117 are preferably tensioned at the other end of the girder opposite to the one end.

In addition, when the length of the girder in FIG. 11 exceeds 40m, the first central strand 111, the first side strand 112, the second side strand 113, and the second central strand 114 are tensioned at one end of the girder. and the third side strand 115, the fourth side strand 116, the fifth side strand 118, and the sixth side strand 119 are preferably tensioned at the other end of the girder opposite to the one end.

12 is a cross-sectional view showing a seventh embodiment of a PS girder according to the present invention, and FIG. 13 is a cross-sectional view showing an eighth embodiment of a PS girder according to the present invention.

On the other hand, the aforementioned PS girder 100 may be installed such that the transverse curved reinforcement 120 for suppressing the occurrence of buckling of the girder in the center of the girder along the longitudinal direction of the girder is interpolated as shown in FIGS. 12 and 13 . Any one of steel bars, H-beams, L-beams, T-beams, and C-beams may be used as the transverse curved reinforcing material 120 .

The transverse curvature reinforcing material 120 functions to minimize transverse curvature displacement that may occur due to the difference in tensile force in the tension force introduction steps ( S10 , S20 , S30 ).

In addition, a pair of transverse curvature reinforcing materials 120 may be provided so as to be symmetrical on both left and right sides with respect to the vertical neutral axis (VNA) of the girder in order to inhibit the occurrence of transverse curvature. And the pair of buckling reinforcement 120 may be provided on the upper part of the girder, the lower part of the girder, or both in order to prevent the occurrence of buckling of the girder.

Specifically, instead of interpolating the H-beam steel, which is the transverse curvature reinforcing material 120, into the girder in a *?* shape suitable for vertical buckling prevention, it is preferable to interpolate into the girder in an H-shape as shown in FIG. 12 to prevent transverse curvature. .

And the transverse curvature reinforcing material 120, the L-beam, is interpolated in a 'L' shape at the right end of the upper flange of the girder to prevent transverse curvature and maximize the cross-sectional rigidity in the vertical direction, as shown in FIG. 13 . And the L-beam is interpolated to the left end of the upper flange so as to be symmetrical with respect to the vertical neutral axis (VNA).

In addition, the transverse curved reinforcement 120 is preferably formed in a length of 0.1 to 0.3 times the length of the girder. At this time, if the transverse curved reinforcing material 120 is formed to be less than 0.1 times the length of the girder, there may be a problem that the function of preventing buckling is not expressed. And when the transverse curved reinforcing material 120 is formed to exceed 0.3 times the length of the girder, the improvement in the function of preventing buckling is insignificant, but the manufacturing cost increases and thus economic efficiency may be reduced.

14 is a plan view showing a PS girder provided with a concrete protrusion according to the present invention, and FIG. 15 is a cross-sectional view showing a PS girder provided with a concrete protrusion according to the present invention.

14 and 15, the girder according to the present invention may include a concrete protrusion provided to protrude from the upper flange at the center of the upper flange along the longitudinal direction of the upper flange in order to inhibit the occurrence of lateral curvature.

As shown in FIG. 15 , the concrete protrusion may be provided on the side surface or the bottom surface at both ends of the upper flange based on the longitudinal direction of the upper flange.

It is preferable that such a concrete protrusion is formed with a length of 0.1 to 0.3 times the length of the girder. At this time, if the concrete protrusion is formed to be less than 0.1 times the length of the girder, there may be a problem that the function to prevent buckling is not expressed. And when the concrete protrusion is formed to exceed 0.3 times the length of the girder, the improvement of the function to prevent buckling is insignificant, but the manufacturing cost increases, so that economic efficiency is deteriorated and workability is deteriorated.

In addition, the upper limit of the width of the concrete protrusion provided to the side at both ends of the upper flange may be determined according to the distance between the girders and the width of the girders installed parallel to the girders. More specifically, the width of the concrete protrusion is formed to have a length of (interval between girders - the width of the girder)/2 or less. For example, if the interval between the girder and the adjacent girder is 2.6m and the width of the girder is 1.2m, it is preferable that the concrete protrusion be formed to have a width of 0.7m or less.

Figure 16 is a plan view for explaining the compressive force generated when the tension of the strand installed in the existing PS girder, Figure 17 is a plan view for explaining the compressive force generated when the tension of the strand installed in the PS girder according to the present invention.

As shown in FIG. 16, in the existing girder, in which anchorages are formed in a line based on the vertical direction of the girder, when tensioning the strand through the anchorage, the central axis of the girder and the tension axis of the strand coincide, so the tension by the strand is Since it is introduced only in one direction (central axis direction), transverse curvature occurs when the strand is tensioned.

On the other hand, the PS girder manufactured by the method of manufacturing a PS girder according to the present invention does not coincide with the central axis of the girder and the tension axis of the strand when tensioning the strand as shown in FIG. 17, so the center of the girder depends on the position of the strand. Compressive forces of different magnitudes are introduced respectively in the axial direction and in the opposite direction. Thereby, the PS girder suppresses the occurrence of lateral curvature during tension of the strand.

The present invention provides a method of constructing a girder bridge using the prestressed girder manufactured by the manufacturing method of the prestressed girder for improving lateral curvature.

18 is a flowchart for explaining the construction method of the girder bridge according to the first embodiment of the present invention, and FIG. 19 is a flowchart for explaining the construction method of the girder bridge according to the first embodiment of the present invention.

18 and 19, the construction method of the girder bridge according to the first embodiment of the present invention is a construction method of a short span girder bridge, and one end of the prestressed girder is mounted on the first abutment 310, and the one end A mounting step (S110) of mounting the other end opposite to the second abutment 320 (S110), a coupling step (S120) of fixing one end of the prestressed girder to the first abutment 310, and an upper portion of the prestressed girder In the slab pouring step (S130) of pouring and curing the slab concrete 400, and raising the other end of the prestressed girder mounted on the second abutment 320, compressive force on the slab concrete 400 integrated into the prestressed girder Including a compressive force introduction step (S140) to introduce.

In the mounting step (S110) constituting the construction method of the girder bridge according to the present invention, one end of the prestressed girder is mounted on the first abutment 310 in order to be fixed to the first abutment 310, and the other end opposite to the one end is mounted on the first abutment 310. It is mounted on the height adjusting device installed on the second abutment 320 .

In the coupling step (S120) constituting the construction method of the girder bridge according to the present invention, a connecting means is installed between one end of the prestressed girder and the first abutment 310 to connect one end of the prestressed girder and the first abutment 310. combine

For example, in the coupling step (S120), a plurality of steel rods are embedded in the first abutment 310 in the vertical direction, and a connection steel plate having a connection hole is installed in the lower part of one end of the prestress girder, and the connection of the connection steel plate Assemble the connecting steel plate and the steel rod so that the steel rod is inserted into the hole.

In the slab pouring step (S130) constituting the construction method of the girder bridge according to the present invention, sleeve concrete is installed so that vehicles, etc. can pass through the upper part of the prestressed girder. If necessary, in the slab pouring step (S130), concrete is poured from the upper surface of the first abutment 310 to the lower surface of the slab concrete 400 so that the prestressed girder, the first abutment 310, and the slab concrete 400 are integrated. and curing.

In the compressive force introduction step (S140) constituting the construction method of the girder bridge according to the present invention, the other end of the prestressed girder mounted on the second abutment 320 is raised through the height adjusting device to introduce the compressive force to the slab concrete 400. make it As described above, the compressive force previously introduced into the slab concrete 400 can offset the tensile force generated in the slab concrete 400 according to the use of the girder bridge, thereby preventing cracks in the slab concrete 400 .

20 is a flowchart for explaining the construction method of the girder bridge according to the second embodiment of the present invention, and Figure 21 is a flowchart for explaining the construction method of the girder bridge according to the second embodiment of the present invention.

20 and 21, the construction method of the girder bridge according to the second embodiment of the present invention is a construction method of a two-span girder bridge.

The construction method of such a girder bridge consists of a first prestressed girder (hereinafter abbreviated as 'first PS girder') and a second prestressed girder composed of a prestressed girder manufactured by a manufacturing method of a prestressed girder for improving lateral curvature. (hereinafter abbreviated as 'second PS girder') are arranged to face each other on a straight line, and the end of the first PS girder 100 adjacent to the second PS girder 200 and the first PS girder 100 A lifting step (S210) of raising the end of the second PS girder 200 adjacent to the, and the raised first PS girder 100 end and the second PS girder 200 end of the upper end of the slab concrete 400 is poured It includes a slab installation step (S220), and a lowering step (S230) of lowering the end of the raised first PS girder 100 and the end of the second PS girder 200.

The ascending step (S210) constituting the construction method of the girder bridge according to the present invention includes a mounting process, a coupling process, and an ascending process.

The mounting process is a process of mounting the first PS girder 100 and the second PS girder 200 on the first abutment 310 and the second abutment 320 and the pier 330 so as to face each other in a straight line. At this time, the height adjusting device 500 is installed on the upper portion of the pier 330 located between the first abutment 310 and the second abutment 320 . In other words, the height adjusting device 500 is installed between the first PS girder 100 and the pier 330 and between the second PS girder 200 and the pier 330 , respectively.

The bonding process is a process performed after the deferment process. In this coupling process, one end of the first PS girder 100 is fixed to the first abutment 310 , and one end of the second PS girder 200 is fixed to the second abutment 320 .

The ascent process is a process performed after the bonding process. In this ascending process, the end of the first PS girder 100 adjacent to the second PS girder 200 and the second PS girder 200 adjacent to the first PS girder 100 through the height adjusting device 500. raise the end. This ascending process is a process to recover the loss of pre-stress force generated in the central part of the PS girder after the production of the PS girder, and to offset the tensile stress generated in the central part of the girder by subsequent descent.

In the slab installation step (S220) constituting the construction method of the girder bridge according to the present invention, the adjacent first PS girder 100 and the second PS girder 200 are connected, and the first PS girder 100 and the second The sleeve concrete 400 is installed so that a vehicle, etc. can pass through the upper part of the PS girder 200 so that the first PS girder 100 and the second PS girder 200 are continuous with each other.

More specifically, in the slab installation step (S220), the slab concrete 400 is poured and cured on the upper portions of the first PS girder 100 and the second PS girder 200 .

If necessary, crossbeam concrete may be poured and cured between the first PS girder 100 and the second PS girder 200 . This crossbeam concrete provides a function of connecting the spaced apart spaces of the first PS girder 100 and the second PS girder 200, while connecting the neighboring girders in the left and right directions.

The slab concrete 400 is a crossbeam provided between the upper part of the first PS girder 100 , the upper part of the second PS girder 200 , and the first PS girder 100 and the second PS girder 200 . It can be poured integrally on top of concrete.

In the descending step (S230) constituting the construction method of the girder bridge according to the present invention, the first and second girders (100, 200) disposed at a higher position than the other end (the end located in the opposite direction to the neighboring girder) through the ascending step (S210) It is a step of lowering one end (the end facing the neighboring girder) to the position of the other end. In this step (S230), one end of the first and

second girders

100 and 200 is lowered through the height adjusting device 500 to introduce a compressive force to the slab concrete 400 .

In this descending step (S230), the tensile stress may be introduced into the slab concrete 400 and cracking may occur, but the tensile stress is resolved by the compressive stress introduced through the ascending step (S210).

22 is a flowchart for explaining the construction method of the girder bridge according to the third embodiment of the present invention, and FIG. 23 is a flowchart for explaining the construction method of the girder bridge according to the third embodiment of the present invention.

22 and 23, the construction method of the girder bridge according to the third embodiment of the present invention is a construction method of a three-span girder bridge.

The construction method of such a girder bridge consists of a first PS girder 100, a third PS girder 600, and a second PS girder 200 composed of a prestressed girder manufactured by a manufacturing method of a prestressed girder for improving lateral curvature. Arranged to face each other on a straight line, the first PS girder 100 and the third PS girder 600 and the third PS girder 600 and the adjacent portion of the second PS girder 200 is raised to raise Step (S310), the first PS girder 100, the second PS girder 200, and the third PS girder 600, the slab installation step of pouring the slab concrete 400 on the top (S320), and the raised and a lowering step 3230 of lowering the adjacent portions of the first PS girder 100 and the third PS girder 600 and the adjacent portions of the third PS girder 600 and the second PS girder 200 .

The ascending step (S310) constituting the construction method of the girder bridge according to the present invention includes a mounting process, a coupling process, and an ascending process.

The mounting process constituting the raising step (S310) is sequentially performed with the first shift 310 and the first PS girder 100, the third PS girder 600, and the second PS girder 200 to face each other on a straight line. It is a process of mounting on the second abutment 320 and the pier 330 .

At this time, the pier 330 may be composed of a first pier and a second pier provided at the front end and the rear end of the third PS girder 600 . And the first pier 330 and the upper portion of the second pier 330 is a height adjustment device 500 is installed. In other words, the height adjusting device 500 is installed between the first PS girder 100 and the first pier 330 and between the second PS girder 200 and the second pier 330 , respectively.

The bonding process constituting the rising step (S310) is a process that proceeds after the mounting process, and one end of the first PS girder 100 is fixed to the first abutment 310, and the second PS girder 200 is fixed. One end of the is fixed to the second abutment (320).

The ascending process constituting the ascending step (S310) is a process performed after the combining process. In this ascending process, the end of the first PS girder 100 and the third PS girder 600 adjacent to the third PS girder 600 together with both ends of the third PS girder 600 through the height adjusting device 500 ) to raise the end of the second PS girder 200 adjacent to. This ascending process is a process to recover the loss of pre-stress force generated in the central part of the PS girder after the production of the PS girder, and to offset the tensile stress generated in the central part of the girder by subsequent descent.

In the slab installation step (S320) constituting the construction method of the girder bridge according to the present invention, the adjacent first PS girder 100 and the third PS girder 600 are connected, and the third PS girder 600 and the second It connects between the PS girder 200, and the sleeve concrete 400 is formed so that a vehicle can pass through the upper part of the first PS girder 100, the second PS girder 200, and the third PS girder 600. By installing the first PS girder 100, the second PS girder 200, and the third PS girder 600 are serialized with each other.

More specifically, in the slab installation step (S320), the first PS girder 100, the second PS girder 200, and the slab concrete 400 is poured and cured on the upper portion of the PS girder 600.

If necessary, crossbeam concrete may be poured and cured between the first PS girder 100 and the third PS girder 600 , and also between the third PS girder 600 and the second PS girder 200 . It is also possible to pour and cure cross-beam concrete. This crossbeam concrete connects the separation space of the first PS girder 100 and the third PS girder 600, and connects the separation space of the third PS girder 600 and the second PS girder 200, in the left and right direction It provides the function of connecting neighboring girders with

In this case, the slab concrete 400 is the upper part of the first PS girder 100 , the upper part of the third PS girder 600 , the upper part of the second PS girder 200 , and the first PS girder 100 and It may be integrally poured on the upper part of the crossbeam concrete provided between the third PS girder 600 and the upper part of the crossbeam concrete provided between the third PS girder 600 and the second PS girder 200 .

In the descending step (S330) constituting the construction method of the girder bridge according to the present invention, it is a step of lowering the adjacent portion of each PS girder raised through the ascending step (S310) to the initial position. In this step (S330), both ends of the third PS girder 600 through the height adjustment device 500 in order to introduce a compressive force to the slab concrete 400, the front end of the first PS girder 100 and the second PS girder Both ends of the third PS girder 600 are lowered to be positioned on the same line as the rear end of the 200 .

In this descending step (S330), tensile stress may be introduced into the slab concrete 400 to cause cracking, but the tensile stress is resolved by the compressive stress introduced through the ascending step (S210).

Although described above with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the following claims. You will understand that you can.

Claims

In the manufacturing method of a girder in which two side strands disposed on the left and right of the girder vertical neutral axis are installed,

a beam manufacturing step of manufacturing a beam by installing two or more anchorages to which the side strands are to be connected;

A first tension force introduction step of tensioning the first side strand with a first tension force that is less than the design tension force;

a second tension force introduction step of tensioning the second side stranded wire with a second tension force that is less than or equal to the design tension while exceeding the first tension; and

A method of manufacturing a prestressed girder for improving transverse curvature, comprising the step of introducing a third tension force overlapping the first tension force and re-tensioning the first side stranded wire with a third tension force that is greater than or equal to the second tension force and less than or equal to the design tension force .
According to claim 1, wherein the anchorage

A method of manufacturing a prestressed girder for improving transverse curvature, characterized in that the center is installed to coincide with the horizontal neutral axis of the beam section within an error range of 16.67%.
According to claim 1,

In the step of introducing the first tension force, the first side strand is tensioned with a tension of 50% of the design tension,

In the step of introducing the second tension force, the second side strand is tensioned with 100% tension,

The third tension force introduction step is a method of manufacturing a prestressed girder for improving transverse curvature, characterized in that the first side strand is tensioned with the remaining 50% of the design tension.
According to claim 1, after the third tension force introduction step

a fourth tension force introduction step of tensioning the third side strand located in the diagonal direction of the first side strand with respect to the vertical neutral axis to a fourth tension force that is less than the design tension;

a fifth tension force introduction step of tensioning a fourth side strand located in a diagonal direction of the second side strand with respect to the vertical neutral axis to a fifth tension force that is less than or equal to the design tension while exceeding the fourth tension; and

Prestress for improving transverse curvature, characterized in that it further comprises the step of introducing a sixth tension force superimposed on the fourth tension force and tensioning the third side strand with a sixth tension force that is greater than or equal to the fifth tension force and less than or equal to the design tension force How to make a girder.
According to claim 4, When the length of the girder is 40m or less

The method of manufacturing a prestressed girder for improving transverse curvature, characterized in that the first to fourth side strands are tensioned at the ends in the same direction.
According to claim 4, If the length of the girder exceeds 40m

The first side strand and the second side strand are tensioned at one end, and the third side strand and the fourth side strand are tensioned at the other end opposite to the one end. Prestressed girder for improvement of lateral curvature production method.
According to claim 1, wherein the girder

A method of manufacturing a prestressed girder for improving transverse curvature, characterized in that the transverse curvature reinforcement is installed to be interpolated to suppress the occurrence of buckling in the center of the girder along the longitudinal direction of the girder.
The method of claim 7, wherein the transverse curved reinforcement

A method of manufacturing a prestressed girder for improving lateral curvature, characterized in that it is any one of steel bars, H-beams, L-beams, T-beams, and C-beams.
The method of claim 7, wherein the transverse curved reinforcement

A method of manufacturing a prestressed girder for improving lateral curvature, characterized in that it is formed with a length of 0.1 to 0.3 times the length of the girder.
The method of claim 7, wherein the transverse curved reinforcement

A method of manufacturing a prestressed girder for improving transverse curvature, characterized in that a pair is provided so as to be symmetrical on both left and right sides based on the vertical neutral axis of the girder in order to suppress the occurrence of transverse curvature.
11. The method of claim 10, wherein the pair of transverse curved stiffeners

A method of manufacturing a prestressed girder for improving lateral curvature, characterized in that it is provided on the upper part of the girder, the lower part of the girder, or both.
According to claim 1, wherein the girder

upper flange;

lower flange;

Abdomen connecting the upper and lower flanges;

A method of manufacturing a prestressed girder for improving transverse curvature, characterized in that it consists of a concrete protrusion provided to protrude from the upper flange at the center of the upper flange along the longitudinal direction of the upper flange in order to suppress the occurrence of transverse curvature.
13. The method of claim 12, wherein the concrete protrusion

A method of manufacturing a prestressed girder for improving transverse curvature, characterized in that it is provided on the side or bottom at both ends of the upper flange based on the longitudinal direction of the upper flange.
The construction method of a girder bridge using the prestressed girder manufactured by the manufacturing method of the prestressed girder for improving lateral curvature according to claim 1 .
15. The method of claim 14,

a mounting step of mounting one end of the prestressed girder on a first abutment, and mounting the other end opposite to the one end on a second abutment;

a coupling step of fixing one end of the prestressed girder to the first abutment;

Slab pouring step of pouring and curing the slab concrete on the upper part of the prestressed girder; and

A method of constructing a girder bridge comprising the step of introducing a compressive force to the slab concrete integrated into the prestressed girder by raising the other end of the prestressed girder mounted on the second abutment.
15. The method of claim 14,

The first prestressed girder and the second prestressed girder composed of the prestressed girder are arranged to face each other in a straight line, and the end of the first prestressed girder adjacent to the second prestressed girder and the first prestressed girder are adjacent a lifting step of raising the end of the second prestressed girder;

A slab installation step of pouring slab concrete on top of the raised end of the first prestressed girder and the end of the second prestressed girder; and

A method of constructing a girder bridge comprising a lowering step of lowering the raised end of the first prestressed girder and the end of the second prestressed girder.
15. The method of claim 14,

The first prestressed girder, the third prestressed girder, and the second prestressed girder are arranged to face each other in a straight line, and adjacent portions of the first and third prestressed girder and the third prestressed girder are arranged to face each other in a straight line. a lifting step of raising the adjacent portions of the prestressed girder and the second prestressed girder;

a slab installation step of pouring slab concrete on top of the first prestressed girder, the second prestressed girder, and the third prestressed girder; and

A method of constructing a girder bridge comprising a lowering step of lowering the raised adjacent portions of the first prestressed girder and the third prestressed girder and the adjacent portions of the third prestressed girder and the second prestressed girder.