KR102209189B1 - Prestressed concrete girder for bridge and method thereof - Google Patents

Abstract

The present invention relates to a prestressed concrete girder for a bridge and a manufacturing method thereof. According to the present invention, the prestressed concrete girder for a bridge comprises: a first tendon accommodation unit extended to a first-first settlement height on one end of a concrete unit from a first-second settlement height on the other end of the concrete unit; a first tendon accommodated in the first tendon accommodation unit to be mounted while tensile force is introduced to introduce a prestress to the concrete unit; a second tendon accommodation unit extended from a second-first settlement height of one end of the concrete unit to a second-second settlement height on the other end of the concrete unit; and a second tendon accommodated in the second tendon accommodation unit to be mounted while tensile force is introduced to introduce a prestress to the concrete unit. The second-first settlement height on one end of the concrete unit is higher than the first-first settlement height. The first-second settlement height on the other end of the concrete unit is higher than the second-second settlement height. A tendon introducing the prestress to the concrete unit of the PSC girder is placed to be substantially inclined in one direction from an upper side on one end of the concrete unit to the lowest side on the other end. The tendon accommodation unit can be tightly charged by grout, so the tendon introducing the prestress to the concrete unit of the PSC girder is definitely prevented from corroding. Accordingly, effects of the present invention guarantee a PSC girder with a reliable and durable operational life.

Description

Prestressed concrete girder for bridge and its manufacturing method {PRESTRESSED CONCRETE GIRDER FOR BRIDGE AND METHOD THEREOF}

The present invention relates to a prestressed concrete girder for bridges and a method of manufacturing the same, and more particularly, to suppress the occurrence of empty spaces of grout filled in the tendon receiving part, and when prestressing is introduced into the prestressed concrete (PSC) girder for bridges The present invention relates to a prestressed concrete girder for bridges that prevents lateral deformation of the girder, lowers the shape height of the girder, and improves the construction convenience and economy, and a method of manufacturing the same.

In general, in the prestressed concrete girder bridge, a prestressed concrete girder is mounted on a lower structure such as a bridge pier or a bridge, and a floor plate through which vehicles or pedestrians pass on the upper surface of the girder is synthesized and constructed. The load acting on the bridge is a fixed load and a live load according to the passage of vehicles, etc., and compression prestress is introduced under the girder neutral shaft to increase the load-bearing capacity of the bridge.

A method widely used as a method of introducing prestress to the prestressed concrete girder for a bridge is a parabolic form in which a tendon (T) is convex downward on the concrete part 12 of the bridge girder 9, as shown in Fig. 1A. The tendon (T) is pulled from the end of the concrete part (12) to introduce a tensile force, and the tendon (T) is fixed in the fixing part (14a) at the end of the girder in a state where the tensile force is introduced.

However, in arranging the fixing part 14a at the end of the conventional prestressed concrete girder (PSC girder 9), in order to prevent excessive stress from being locally concentrated on the concrete part 12, the fixing part 14a There is a limitation that the interval 14h must be sufficiently separated. For this reason, when the tendon (T) is longitudinally arranged in a plurality of rows on the prestressed concrete girder (9), each tendon (T, as will be described later, the term'tendon' described in the present specification and claims is a number of It is defined as referring to that the strands are formed in the form of bundles.) Since it is necessary to secure the gap between the fixing portions 14h of the girder, the problem of increasing the height (H) of the girder has arisen.

In addition, it is advantageous to offset the load acting on the girder during common use by introducing pre-stress while the tendon installed in the concrete girder is located as low as possible from the center of the girder. For this purpose, the tendon at the central part of the girder is also arranged at a location that is transversely spaced from the abdomen of the concrete girder. However, the tendon of the conventional prestressed concrete girder (PSC girder, 9) is difficult to be symmetrically arranged horizontally with respect to the central axis of the cross section in the longitudinal direction of the girder. Accordingly, a difference in stiffness occurs in the left and right sections based on the central axis of the cross section, and the friction loss stress in the left and right tendons varies when prestress is introduced. In addition, in the case of introducing the same tensile force to the tendons arranged on the left and right based on the central axis of the cross section, if the tensile force is first introduced to either of the left and right tendons, the tendon to which the tensile force was introduced will have rigidity with the concrete girder. Therefore, when the tensile force is later introduced to another tendon, a stress difference is induced in the left and right sections based on the central axis of the concrete cross section. These phenomena cause stress imbalance in the left and right tendons when prestress is introduced, and even if tendons are symmetrically arranged with respect to the central axis of the cross section at the center of the girder due to this stress imbalance, lateral deformation occurs in the girder when prestress is introduced, making construction difficult. The problem of lowering the reliability of the load-bearing capacity has also arisen.

On the other hand, in the prestressed concrete girder (PSC girder), grout is injected into the tendon receiving portion (S, sheath tube) surrounding the tendon (T) after the prestress is introduced into the tendon. At this time, as shown in Fig. 1B, the tendon accommodating portion disposed at the lowermost end in the longitudinal direction is disposed in an almost straight line. For grout injection, when grout is injected (55i) into the tendon receiving portion (S) through the grout inlet (14x), the injected grout passes through the tendon receiving portion (S) and the grout flows out (55o) to the grout outlet (14y). It is done by confirming what is being done.

However, since the tendon accommodating portion (S) is arranged in a nearly straight line in the longitudinal direction of the tendon accommodating portion disposed at the bottom, grout due to the pressure difference between the head pressure between the grout inlet and the outlet that occurs when the tendon accommodating portion is inclined It is not possible to expect the tight filling effect of 55), so an empty space due to air (air) is created in the tendon receiving part.

The empty space in the tendon accommodating part (S) induces corrosion of the tendon (T), and the corrosion progress rate in the tendon in the state in which the tensile force is introduced proceeds faster, so the inner space of the tendon accommodating part (S) is tightly closed. There is an urgent need to recharge.

On the other hand, the process of introducing prestress to the concrete girder is achieved by sequentially tensioning a plurality of tendons. However, whenever the process of introducing prestress by tensioning the tendon in one anchorage is performed, the length of the concrete girder gradually decreases due to compression deformation, and the tensile force introduced in the tendon which was previously used to introduce the prestress gradually decreases. There is a phenomenon that the size of the pre-stress that has already been introduced decreases.

In order to solve such a problem, a method of introducing tensile force to the tendon at the same time in several anchorage units was sought, but the introduction of tensile force by installing tension jacks in two or more anchoring units at the same time is rather a girder because the gap between the tension jacks is narrow. It also contributed to the formation of a larger cross section.

From this, there is a need for a method of reducing the cross section of the concrete section and lowering the mold height of the girder while introducing prestress of the same size to the concrete section. At the same time, there is an urgent need for a method of minimizing the occurrence of lateral deformation and the loss of the prestress already introduced in the process of introducing prestress to the concrete girder.

An object of the present invention is to tightly fill a tendon receiving portion (for example, a sheath pipe) of a concrete girder for a bridge with grout.

In addition, an object of the present invention is to lower the mold height in a state where it is mounted on a bridge lower structure such as a bridge pier or an abutment by providing a cutout formed at the lower sides of both ends of the girder.

At the same time, an object of the present invention is to sufficiently secure a gap between the tendon anchorages of the bridge girder to lower the mold height and to minimize the cross section of the concrete section to improve economic efficiency.

In addition, an object of the present invention is to prevent the lateral deformation of the girder by simultaneously performing the process of tension fixing the tendons arranged in the left and right symmetry of the PSC girder.

In addition, it is an object of the present invention to minimize the number of prestress introduction processes using tendons of a PSC girder, thereby minimizing the loss of prestress previously introduced by multi-stage introduction.

In addition, it is an object of the present invention to provide a way to diversify the arrangement of tendons in the concrete part of the bridge girder.

In addition, the present invention suppresses the force acting on the surrounding concrete part at the branch point of the tendon even if tensile force is introduced while the tendon disposed in one main passage is divided into two and is embedded in the concrete part of the bridge girder. It aims to obtain durability and reliability at the same time.

In addition, the present invention implements a PSC girder for a bridge using a tendon distribution mechanism in which a plurality of strands constituting a tendon are distributed from one main passage to two sheath pipes or merged from two sheath pipes into one main passage. It aims to do.

Above all, the present invention is a girder in which a plurality of tendons are arranged in a concrete part, even if the fixed height of one end and the fixed height of the other end are different from each other in a predetermined position without interference from different tendons. The purpose of the tendon is to be placed correctly.

On the other hand, the present invention aims to accurately introduce only the prestress of an appropriate size to the prestress girder for bridges by adjusting the size of the prestress introduction in the form of a multi-step step in response to the distribution of the bending moment actually acting during common use on the PSC girder. do.

In order to achieve the above object, the present invention, and the concrete portion reinforced inside; A first tendon accommodating portion extending from the 1-2 fixing height of the other end of the concrete part to the 1-1 fixing height of one end of the concrete part; A first tendon accommodated in the first tendon receiving portion and fixed in a state in which a tensile force is introduced to introduce prestress to the concrete portion; A second tendon accommodating part extending from a 2-1 fixing height of one end of the concrete part to a 2-2 fixing height of the other end of the concrete part; A second tendon accommodated in the second tendon accommodating portion and fixed in a state in which a tensile force is introduced to introduce prestress to the concrete portion; It is configured to include, wherein the 2-1 fixing height at one end of the concrete part is higher than the 1-1 fixing height, and the 1-2 fixing height at the other end of the concrete part is higher than the 2-2 fixing height It provides a prestressed concrete girder for bridges, characterized in that.

On the other hand, the present invention, as a method of manufacturing a prestressed concrete girder for a bridge, the reinforcement step of reinforcing the reinforcement to the position where the concrete part is formed; A first tendon receiving part is installed so as to extend from the 1-2 fixing height of the other end of the concrete part to the 1-1 fixing height of one end of the concrete part, and the other end of the concrete part from the 2-1 fixing height of one end of the concrete part Install a second tendon accommodating part at a 2-2 fixing height of, wherein the 2-1 fixing height at one end of the concrete part is higher than the 1-1 fixing height, and the 1-2 at the other end of the concrete part A tendon accommodating part installation step of installing the first tendon accommodating part and the second tendon accommodating part so that the fixing height is higher than the 2-2 mounting height; A formwork installation step of installing a formwork for forming the concrete part; A concrete forming step of curing the concrete by pouring unhardened concrete into the formwork to form the concrete part; In a state in which the first tendon is accommodated in the first tendon accommodating part and the second tendon is accommodated in the second tendon accommodating part, the concrete part is fixed in a state in which a tensile force is introduced into the first tendon and the second tendon. A pre-stress introduction step of introducing pre-stress to; A grout injection step of injecting grout to the first tendon receiving portion and the second tendon receiving portion; It provides a method of manufacturing a prestressed concrete girder for a bridge, characterized in that configured to include.

The'longitudinal direction' or'longitudinal direction' described in the present specification and claims is defined as referring to the longitudinal direction of the prestressed girder for a bridge (for example, the bridge axis direction in the case of a girder installed on a straight bridge). The'axial direction' described in the present specification and claims is defined as referring to the extension direction of the sheath tube. The'radial direction' described in the specification and claims is defined as referring to a direction away from a plane perpendicular to the axial direction with respect to the central axis of the axial direction, which is the extension direction of the sheath tube.

The'central portion' or'span central portion' described in the specification and claims is defined as referring to the central portion of the girder based on the longitudinal direction of the prestressed girder for a bridge.

The'up-down direction' and terms similar thereto described in the specification and claims are defined as referring to the orientation of the girder. In addition, the terms'width direction','transverse direction','left and right direction' and similar terms described in this specification and claims refer to a direction perpendicular to the vertical direction and the longitudinal direction (for example, a direction perpendicular to the bridge axis of the girder). It is defined as doing.

The'cross-sectional central axis (Cx)' described in the present specification and claims is like an axis penetrating in the vertical direction of the abdomen in a horizontally symmetrical cross-section of the center of the abdomen of the girder, in the horizontal direction (transverse direction) of the cross-section of the girder concrete part It is defined as referring to the central axis of In addition, a cross-section in which the cross-sectional central axis Cx extends in the longitudinal direction of the girder is defined as a'transverse central vertical cross-section'.

The term'tendon' described in the specification and claims is defined as referring to a bundle of strands consisting of a plurality of strands. And,'one tendon is distributed into two tendons through the tendon distribution mechanism' is that the strands of strands that make up one tendon are separated into two bundles (bundles) to form one tendon each. It is defined as a collective term that the strands of the above bundles (bundles) are combined to form a single bundle, a tendon. And,'tendon insertion' is defined as referring to the insertion of the strands constituting the tendon.

According to the present invention, the tendon for introducing prestress to the concrete part of the PSC girder is arranged inclined from one end to the other end of the concrete part, and it is possible to obtain an advantageous effect of tightly filling the tendon receiving part using the head pressure of the grout.

Through this, the present invention can reliably prevent corrosion of tendons introducing prestress to the concrete portion of the PSC girder, thereby ensuring the PSC girder having a reliable endurance life.

According to the present invention, it is possible to obtain the effect of lowering the mold height in the state of being mounted on the lower structure of a bridge by providing a cutout formed at the lower side of both ends of the girder.

At the same time, according to the present invention, it is possible to obtain the effect of variously configuring tendon arrangements in the concrete part of the PSC girder by having a tendon receiving portion in which one main passage in which the tendon is accommodated is branched into two branch passages.

Through this, the present invention is that even if there are multiple tendons that introduce prestress to the concrete part of the PSC girder, one tendon continuous in the longitudinal direction without interference from other tendons is lower than this from the 2-1 mounting height of one end of the concrete part. It is formed to be inclined at the 2nd-2 fixing height of the other end, and as the tendon receiving portion is formed inclined, it is possible to obtain a tight filling effect of the grout due to the difference in head pressure between the grout inlet and the outlet.

According to the present invention, two rows of tendons arranged in the concrete part of the PSC girder are configured to be settled in one fixing part, and the number of fixing parts is reduced even when the tendons of the same row as in the prior art are arranged in the concrete part to lower the mold height and reduce the concrete cross section. The effect of improving economics can be obtained.

In addition, according to the present invention, tendons are symmetrically arranged in the longitudinal direction with respect to the central axis of the cross section in the concrete part of the PSC girder, and tendons arranged symmetrically are manufactured by simultaneously introducing prestress. The effect of preventing lateral deformation can be obtained.

And, according to the present invention, since it is possible to introduce a tensile force to two rows of tendons arranged in the concrete part at a time with one tension jack, the number of tension and settling is reduced compared to the prior art, and the prestress introduced before is the prestress introduced after that. The effect of minimizing loss during the introduction process can also be obtained.

In addition, according to the present invention, one main passage and two or more branches so that the tendon is distributed from one main passage to two sheath tubes or merged from two sheath tubes into one main passage based on the insertion direction of the tendon. By using the tendon distribution mechanism in which the passage is formed as one body, it is possible to obtain the effect of easily forming a branched tendon receiving portion by connecting a sheath tube to each tube of the tendon distribution mechanism.

Accordingly, the present invention easily implements a structure in which a tendon passing through one main passage is distributed to two branch passages, so that the tensile force introduction and fixing process for the tendons passing through each branch passage can be performed at once. As a result, the construction process is simplified and the advantage of manufacturing the bridge girder is obtained more quickly.

1A is a view showing a tendon arrangement structure of a conventional prestressed concrete girder for a bridge,
1B is a view showing a process of injecting grout into the lowermost tendon receiving portion of FIG. 1A;
Figure 2 is a view showing the configuration of the prestressed concrete girder for a bridge according to the first embodiment of the present invention and a cross-section by position;
3A is a plan view of FIG. 2 taken along the axial direction of the second tendon T2;
3B is a plan view of FIG. 2 taken along the axial direction of the third tendon T3;
3C is a plan view of FIG. 2 taken along the axial direction of the first tendon T1;
4 is a perspective view showing the configuration of a tendon dispensing mechanism according to a first embodiment of the present invention;
Figure 5 is a view for explaining that the force in the transverse direction is generated when the prestress is introduced in the tendon distribution mechanism of Figure 4;
6A is a plan view in which a reinforcing member is installed in the tendon distribution mechanism of FIG. 4;
Fig. 6b is a front view of Fig. 6a;
Figure 7 is a plan view showing another embodiment of the tendon dispensing mechanism of Figure 4;
Figure 8a is a cross-sectional view along the cut line KK of Figure 7;
Fig. 8b is a cross-sectional view taken along line JJ in Fig. 7;
FIG. 9 is a view showing a process of injecting grout into the second tendon (T2) receiving part (S2) of the concrete part of FIG. 2;
10 is a view showing the configuration and positional cross-section of a prestressed concrete girder for a bridge according to a second embodiment of the present invention;
Fig. 11 is a plan view showing the arrangement of the tendon of Fig. 10;

Hereinafter, a prestressed girder 1 for a bridge according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present invention, detailed descriptions of known functions or configurations will be omitted to clarify the gist of the present invention.

The prestressed concrete girder (1, Prestressed Concrete Girder, PSC girder) for a bridge according to the first embodiment of the present invention is, as shown in Figs. 2 to 3C, to a bridge in which prestress is introduced in advance at the lower edge of the central part of the girder. As a concrete girder used, a concrete part 12 with reinforced bars (not shown) laid inside, and a tendon (T1, which is installed in the concrete part 12 and settled in a state where tensile force is introduced) introduces prestress to the concrete part. T2, T3; T), a tendon receiving portion that accommodates each of the tendons (T1, T2, T3), and a state in which a tensile force is introduced to the tendons (T1, T2, T3) located at the end of the concrete section 12 Including the fixing portion 90 to be maintained and fixed, it is configured to introduce prestress into the concrete portion 12 by the tension force introduced into the tendon (T).

The tendons (T1, T2, T3) and tendons branched from them (T11, T12, T21, T22) refer to a bundle shape in which a plurality of strands Ta are gathered.

The second tendon (T2) is from the 2-1 fixing height (H21) located above one end (E1) of the concrete part (1) of the PSC girder (1) to the lowermost fixing part of the other end (E2) of the concrete part (12). It is disposed in the second tendon accommodating portion (S2) while achieving a gentle curvature to 2-2 fixing height (H22). In other words, the second tendon (T2) is arranged inclined downward from the fixing part 90 of the one end (E1) of the PSC girder (1) to the center of the span, and the cross section of the lower flange concrete 12c, which is the lower edge of the neutral axis at the center of the span Pass through wealth. In addition, the second tendon (T2) is arranged at a certain height from the center of the span of the PSC girder (1) to the other end (E2) of the girder, or has a gentle slope, and is the lowest side having a 2-2 fixing height (H22). It extends to the fixing part. Here, a gentle slope from the center of the span of the PSC girder 1 to the other end E2 of the girder means that it is arranged in an inclination having a small size of, for example, 0.1° to 5°. Therefore, since the second tendon T2 is disposed in a substantially inclined shape in one direction as a whole, it is possible to obtain the effect of tightly filling the second tendon receiving portion S2 by the head pressure difference in the process of filling it with grout. .

The second tendon T2 is formed in the form of a single strand of strands in the fixing portions 90 at both ends of the concrete part 12, but as shown in FIG. 3A, the second tendon T21 and the second tendon T21 It is divided into two bundles of strands with two tendons (T22) to form different rows in the width direction, and is installed in the concrete part 12. To this end, the second tendon accommodating portion S2 is formed to branch into two different second-first branch passages and second-second branch passages, respectively, so that one strand of strands is branched from the second tendon (T21). ) And the 2-2 tendon (T22).

According to a preferred embodiment of the present invention, the 2-1 tendon (T21) and the 2-2 tendon (T22) are cross-sectional central axes vertically crossing the center of the abdomen (12b) of the concrete section (12) in the longitudinal direction of the girder. They are arranged symmetrically with respect to (Cx). That is, as shown in FIG. 3A, in the central part of the girder, the 2-1 tendon (T21) and the 2-2 tendon (T22) are arranged symmetrically with respect to the central axis of the cross section (Cx), and the lower side of FIG. As shown in the cross-sectional view, the 2-1 tendon (T21) and the 2-2 tendon (T22) are arranged along the same trajectory based on the front side.

Here, the second tendon (T2) is equally distributed to the 2-1 tendon (T21) and the 2-2 tendon (T22), by the 2-1 tendon (T21) and the 2-2 tendon (T22). The amount of prestress to be introduced can be introduced evenly.

The first tendon (T1) is the 1-1 fixing of one end (E1) of the concrete part 12 from the fixing part of the 1-2 fixing height (H12) of the other end (E2) of the concrete part of the PSC girder (1). It is disposed in the first tendon accommodating part S1 while forming a gentle curvature with the lowermost fixing part of the height H11. Preferably, as shown in FIG. 2, the first tendon T1 is disposed symmetrically with the second tendon T2 based on the center of the span.

That is, the first tendon (T1) is inclined downward from the fixing part 90 located at the 1-2 fixing height (H12) of the other end (E2) of the PSC girder (1) concrete part 12 to the central part of the span. It is disposed, and passes through the inside of the lower flange concrete 12c, which is the lower edge of the neutral axis of the cross section at the center of the span. In addition, the first tendon (T1) is arranged at a certain height from the center of the span of the PSC girder (1) to the one end (E1) of the girder, or has a gentle slope to settle at the lowest side of the 1-1 fixing height (H11). It extends to wealth. Here, the gentle slope from the center of the span of the PSC girder 1 to the one end E1 of the girder means that the PSC girder 1 is arranged at a small slope of 0.1 to 5 ㅀ. Therefore, since the first tendon T1 is disposed in a substantially inclined shape in one direction as a whole, it is possible to obtain the effect of tightly filling the first tendon accommodating part S1 by the head pressure difference in the process of filling it with grout. .

The first tendon T1 is formed in the form of a single strand of strands in the fixing portions 90 at both ends of the concrete part 12, but as shown in FIG. 3C, the 1-1 tendon T11 and the 1- It is divided into two bundles of strands with two tendons (T12) to form different rows in the width direction, and is installed in the concrete part 12. To this end, the first tendon accommodating part S1 is formed to be branched into two different first-first branch passages and first-second branch passages, so that one strand of strands is branched from the first tendon (T11). ) And the 1-2 tendon (T12).

According to a preferred embodiment of the present invention, the 1-1 tendon (T11) and the 1-2 tendon (T12) are cross-sectional central axes that cross the center of the abdomen (12b) of the concrete section (12) vertically in the longitudinal direction of the girder. It is arranged symmetrically in (Cx). That is, as shown in FIG. 3C, in the central portion of the girder, the 1-1 tendon (T11) and the 1-2 tendon (T12) are arranged symmetrically with respect to the central axis (Cx) of the cross section, and the lower side of FIG. As shown in the cross-sectional view, the 1-1th tendon T21 and the 1-2nd tendon T22 are arranged along the same trajectory with respect to the front side.

Here, the first tendon (T1) is equally distributed to the 1-1 tendon (T11) and the 1-2 tendon (T12), by the 1-1 tendon (T11) and the 1-2 tendon (T12). The amount of prestress to be introduced can be introduced evenly.

Here, as shown in Fig. 2, the second tendon (T2) is fixed and fixed at the end (E1) of the concrete part (E1), the 2-1 fixing height (H21) is the first tendon (T1) is the end of the concrete part (E1) The second tendon (T2) is higher than the 1-1 fixing height (H11) fixed and fixed in the first tendon (T1) and the 1-2 fixing height (H12) fixed at the other end (E2) of the concrete part. It is set higher than the 2-2 height (H22) fixed and fixed at the other end of the concrete part (E2). Accordingly, as at least one of the first tendon (T1) and the second tendon (T2) is arranged to be inclined in one direction, a height difference between the grout inlet and the outlet is generated, so that the grout is more tightly filled by the head pressure difference. You can get the effect.

More preferably, the 1-1 fixed position (H11) of the first tendon (T1) located below the end of the concrete part and the 2-2 fixed position (H22) of the second tendon (T2) are the end of the concrete part. It is preferable that it is the lowest position among the fixing parts. Accordingly, both the first tendon (T1) and the second tendon (T2) are definitively inclined in one direction, and accordingly, the tendon receiving unit in which the first tendon (T1) and the second tendon (T2) are accommodated. In the process of filling (S1, S2) with grout, the effect of tightly filling can be obtained due to the difference in head pressure.

In addition, as shown in Fig. 2, the first-second fixed position H12 of the first tendon T1 and the second-first fixed position H12 of the second tendon T2 are on the uppermost side, respectively. It may be a located fixing unit. Accordingly, the inclination of the first tendon T1 and the second tendon T2 is induced to be greater, and thus the head pressure difference in the grout filling process can be made larger.

However, the present invention is not limited thereto, and according to another embodiment of the present invention, only one of the end fixing parts of the first tendon (T1) and the second tendon (T2) may be formed as the lowermost fixing part, and the first Only one of the end fixing parts of the tendon T1 and the second tendon T2 may be formed as the uppermost fixing part.

As described above, since the first tendon (T1) and the second tendon (T2) are arranged in a form in which one end and the other end of the concrete section 12 are substantially inclined downwardly, As a fixed height is formed extending obliquely in only one direction, and arranged in a symmetrical shape crossing each other in the intersecting direction, a uniform prestress is introduced into the cross section along the intersecting direction of the concrete part of the PSC girder, while the first tendon (T1) and It is possible to obtain an effect of tightly filling the grout in the first tendon receiving portion S1 and the second tendon receiving portion S2 in which the second tendon T2 is accommodated.

That is, conventionally, as shown in FIG. 1B, the tendon receiving portion (S) is disposed in a nearly straight line over the entire area, so when the grout 55 is injected, the head pressure difference between the inlet and the outlet is hardly generated, so that the tendon receiving portion ( There was a problem that empty space was created as the amount of air (air) in S) increased.

However, as shown in Fig. 9, when grout is injected (55i) through the grout inlet 14x of the second tendon receiving portion S2, the inlet port is caused by the head pressure difference between the inlet 14x and the outlet 14y. The grout passing through (55i) has a gentle slope or is first filled in the section AA formed with a certain height, and the air (air) existing in this section moves to the inclined section BB. The force to push (55b) toward the grout outlet (55o) by the grout (55b) passing through the section (BB) increases, and the air existing in the tendon receiving portion (S2) is discharged from the outlet (55o) together with the initially injected grout. ) Is discharged to the outside. Accordingly, not only in the downwardly inclined section BB, but also in the section AA having a gentle slope or formed with a constant height, an effect of filling the grout tightly without creating an empty space can be obtained.

In this way, as the grout is tightly filled in the tendon receiving portions T1 and T2 to completely fill the circumference of the tendons T1 and T2 with the grout 55, corrosion of the tendons T1 and T2 in the state in which the tensile force is introduced The advantageous effect of ensuring a reliable durable life is obtained by preventing

On the other hand, as shown in Fig. 3b, the third tendon (T3) is disposed in a downwardly convex parabolic shape between the first tendon (T1) and the second tendon (T2) of the concrete part 12. Both ends of the portion 12 and between them are all formed in the form of a single strand of strands. That is, it is formed in the same or similar to the conventional tendon arrangement shown in Fig. 1A.

That is, in addition to the first tendon T1 and the second tendon T2, the third tendon T3, which is an existing arrangement, may be installed together. However, according to another embodiment of the present invention, the third tendon T3 may be omitted.

On the other hand, the 2-1 fixing height (H21) of one end (E1) of the concrete part 12 of the PSC girder (1) and the 1-2 fixing height (H12) of the other end are the first tendon receiving part and the second tendon. Refers to the height of the fixing unit 91 of the upper fixing unit 90 disposed at the end of the receiving unit. As described above, the 2-1 fixing height H21 of one end and the 1-2 fixing height H12 of the other end are preferably the height of the fixing unit of the uppermost fixing part, but the scope of the present invention is not limited thereto. . Likewise, on the other hand, the 1-1 fixing height (H11) of one end (E1) of the concrete part 12 of the PSC girder (1) and the 2-2 fixing height (H22) of the other end (E2) are accommodated in the first tendon. Refers to the height of the lower anchorage disposed at the ends of the secondary and second tendon accommodating portions. As described above, it is preferable that the 1-1st fixing height H11 of one end and the 2nd-2 fixing height H22 of the other end are the height of the lowermost fixing unit, but the scope of the present invention is not limited thereto.

In addition, in addition to the first tendon (T1) and the second tendon (T2), when a third tendon (T3), which is an existing arrangement, is installed together, T3 is a U-shaped convex downward at the middle or uppermost side of one end. It is possible to freely arrange it in a (parabolic) shape.

On the other hand, the first tendon accommodating portion (S1) is two 1-1 branch passages and the second branch passages, respectively, and the second tendon accommodating portion (S2) is different from each other two 2-1 branch passages. It is formed to branch into the passage and the second-second branch passage. Therefore, even if a plurality of tendons are arranged as in the conventional arrangement as shown in FIG. 3B, the fixing unit other than the positions of the fixing units of the first tendon (T1) and the second tendon (T2) so that interference between tendons does not occur. It can be arranged, and it can be arranged in a U-shaped (parabolic) shape that is convex downward. That is, by configuring one tendon accommodating part to branch into two separate passages, each of which is different from each other, it is possible to prevent the interference of neighboring tendons in the longitudinal direction, thereby obtaining an advantageous effect of distributing tendons more diversely and efficiently. have.

The tendons (T1, T2, T3,...) arranged as described above are installed in a state accommodated in the tendon accommodating parts (S1, S2, S3; S) in the concrete part 12, and the concrete part 12 With sufficient strength, a tensile force is introduced into the tendons (T1, T2, T3,...) disposed in the tendon receiving part, and then settled to introduce prestress to the concrete part 12.

In the first tendon (T1), since one strand of strands is branched into the 1-1 tendon (T11) and the 1-2 tendon (T12), the first tendon accommodating part (S1) for accommodating the first tendon (T1) ) Is provided with a branch passage in which one first main passage is divided into two by a 1-1 sheath tube S11 and a 1-2 sheath tube S12, respectively. Likewise, in the second tendon (T2), since one strand of strands is branched into the 2-1 tendon (T21) and the 2-2 tendon (T22), the second tendon accommodating unit accommodates the second tendon (T2). In (S2), a branch passage in which one second main passage is divided into two is formed into a 2-1 sheath tube (S21) and a 2-2 sheath tube (S22), respectively.

On the other hand, the first main passage, the 1-1 branch passage, and the 1-2 branch passage may be formed only by properly bonding and connecting the 1-1 sheath pipe (S11) and the 1-2 sheath pipe (S12). have. In this case, the 1-1 sheath tube (S11) and the 1-2 sheath tube (S12) form the 1-1 branch path and the 1-2 branch path, and the 1-1 sheath tube (S11) The passage of the section where the and the 1-2 sheath pipe (S12) are combined forms the first main passage. The first main passage, the first-first branch passage, and the first second branch passage may be formed in a form in which the sheath pipes S11 and S12 are connected to the tendon distribution mechanism 100 to be described later.

Similarly, the 2nd main passage, the 2-1 branch passage and the 2nd-2 branch passage are formed only by properly bonding and connecting the 2-1 sheath tube (S21) and the 2-2 sheath tube (S22). You may. In this case, the 2-1 sheath tube (S21) and the 2-2 sheath tube (S22) form the 2-1 branch path and the 2-2 branch path, and the 2-1 sheath tube (S21) The passage of the section where the and the 2-2 sheath pipe (S22) are combined forms a second main passage.

Meanwhile, according to a preferred embodiment of the present invention, the tendon distribution mechanism 100 shown in FIG. 4 may be applied to the first tendon accommodating portion S1 and the second tendon accommodating portion S2. That is, the tendon distribution mechanism 100 applied to the present invention is installed in the concrete part 12 of the bridge girder 1 to distribute the tendon T in the form of a bundle into two or more sheath tubes. Do it.

2 and 4, the tendon distribution mechanism 100 distributes the first tendon (T1) and the second tendon (T2) made of a bundle of strands in two or more paths, and the tendon (T1, T2) The main tube 110 forming the main passage 110p passing through, respectively, the first branch tube 121 and the main passage 110p branching from the main passage 110p to form the first branch passage 121p It is configured to include a plurality of branch passages (121p, 122p) including a second branch tube 122 branching from and forming a second branch passage (122p).

Here, the tendon distribution mechanism 100 is a guide member extending from the branch position Px branched from the main passage 110p to the plurality of branch passages 121p and 122p toward the inlet 110e of the main passage 110p ( 130), the stress concentration preventing member 140 filling the space between the outer circumferential surfaces of the branch tubes 121 and 122 forming each branch passage (121p, 122p), and the branching in a state embedded in the concrete part of the bridge girder It may be configured to include a reinforcing member 150 installed so as to surround the circumference of the region TR where the tendon passing through the passages 121p and 122p meets, and the force that expands in the transverse direction of the main tube 110 acts. .

The first tendon (T1), the 1-1 tendon (T11) branched therefrom, the 1-2 tendon (T12), the second tendon (T2), and the 2-1 tendon (T21) branched therefrom The 2-2 tendon (T22) is formed in the form of a bundle in which a number of strands are gathered. Accordingly, the lecture player of the first tendon (T1) is equal to the sum of the lecture player of the 1-1 tendon (T11) and the lecture player of the 1-2 tendon (T12), and the lecture player of the second tendon (T2) Is equal to the sum of the lecturers of the 2-1 tendon (T21) and the lecturers of the 2-2 tendon (T22). The third tendon T3 is the same as the conventional tendon arrangement that is not branched as described above, and may be omitted in other embodiments of the present invention.

The tendon distribution mechanism 100 is installed in a form embedded in the end of the concrete part 12 of the bridge girder 1 as shown in FIGS. 2 and 3A. For convenience, the reference numeral of the tendon distribution mechanism installed in the first tendon (T1) and the second tendon (T2) is indicated as '100', but the present invention is not limited thereto, and various embodiments attached to the present specification and drawings The tendon distribution mechanism may be applied to one or more of the first tendon (T1) and the second tendon (T2).

The main tube 110 forms one main passage 110p so that both the first tendon T1 and the second tendon T2 fixed in the fixing unit 90 pass through. The main tube 110 may be formed in various cross-sections, but the cross-section including the inlet 110e of the main tube 110 is formed in the same circular cross-section as the cross-sectional shape of the fixing unit 90 as shown in FIG. 8B. It is desirable.

Here, the inlet 110e of the main tube 110 abuts or is coupled to the trumpet member 92 of the fixing unit 90, so that the main passage 110p maintains a state isolated from the concrete unit 12. The first tendon (T1) and the second tendon (T2) passing through the main tube 110 sequentially pass through the trumpet member 92 and the anchoring unit 91, and a wedge member ( Not shown). According to another embodiment of the present invention, the main tube 110 is formed in an integral structure including the trumpet member 92 and may be installed in contact with or coupled to the fixing unit 91. In addition, according to another embodiment of the present invention, a sheath tube having the same diameter as the main tube 110 is coupled without a trumpet member, and the sheath tube may be installed in a form that is coupled to the fixing unit 91.

The branch tubes 121 and 122 are formed extending from the main tube 110 to form two or more branch passages 121p and 122p on the opposite side of the inlet of the main tube 110. Accordingly, a part of the first tendon T1 and the second tendon T2 passing through the main tube 110 of the tendon dispensing device 100 is respectively a first branch passage of the first branch tube 121 ( 121p) and installed in the 1-1 sheath tube (S11) and 2-1 sheath tube (S21), respectively, and passing through the main tube 110 of the different tendon distribution devices 100 ( Other portions of the T1 and the second tendon T2 pass through the second branch passage 122p of the second branch tube 122, respectively, and the 1-2 sheath tube S12 and the 2-2 sheath tube S22. ) Installed within.

Here, the number of strands or the ratio of the cross section that branch the tendon (T) passing through the main tube 110 into two branch tubes can be freely determined, for example, a ratio of 1:2 to 2:1 By controlling the number of stranded wires in the furnace branch tube, the amount of prestress introduced in each area of the concrete part 12 can be freely controlled.

The installation direction of the tendon distribution mechanism 100 and the angle (ang) and direction of the branch tubes 121 and 122 may be determined in various ways. 2 and 3A, the tendon distribution device 100 connected to the upper fixing part 90 of the PSC girder 1 has a first branch tube 121 and a second branch tube 122 in the width direction. The second tendon (T2) branching into and passing through the main tube 110 is branched tubes 121 and 122 branched in the width direction, the 2-1 sheath tube (S21) and the 2-2 sheath tube (S22). ) To distribute some tendons (T21, T22) in the width direction.

Here, the branch tubes 121 and 122 may be directly connected to the sheath tube, and as shown in FIG. 6A, the ends 121e and 122e of the branch tubes 121 and 122 and the sheath tubes S11, S12, S21, S22) may be connected via a connection member 170 connecting each. When connecting the sheath pipes (S11, S12, S21, S22) and the branch tubes 121, 122 via the connection member 170, the connection member 170 is a part of each branch tube (121, 122). Can be considered. Through this, even if there is a difference in the cross-sectional size or shape of the branch tubes 121 and 122 and the sheath tubes S11, S12, S21, S22, a smooth connection can be made.

On the other hand, the branch tubes 121 and 122 extend from the main tube 110 in a form that is opened by an acute angle ang. The angle formed by the main tube 110 and the branch tubes 121 and 122 is such that the angle at which the center lines of the branch tubes 121 and 122 intersect with the center line of the main tube 110 is between 2.5 degrees and 10 degrees. It is desirable. If the angle is less than 2.5 degrees, the length of the main tube 110 constituting the tendon dispensing mechanism becomes too long or the shape of the dispensing mechanism cannot be formed. On the contrary, if the angle is greater than 10 degrees, the horizontal component force at the branch point of the tendon according to the tensile force increases when pre-stress is introduced, so the tensile stress increases in the concrete part, increasing the possibility of local damage to the concrete, and thus the required amount of the reinforcing member 150 Will also increase. In some cases, the section of the concrete section becomes larger than necessary, resulting in an uneconomical section. Here, the distribution angle of 10 degrees indicates that the ratio of the component force at the time of introduction of the prestress is 18% of the tensile force, which can be sufficiently controlled by the reinforcing member 150 disposed at the branch point of the tendon.

The body in which the main tube 110 and the branch tubes 121 and 122 are combined may be formed of a metal material including steel, the same material as the trumpet member 92, or may be formed of a plastic or resin material. have. In addition, it may be formed of a grouting material, or may be formed of ultra-high strength concrete. The body to which the main tube 110 and the branch tubes 121 and 122 are combined may be integrally manufactured.

Here, according to an embodiment of the present invention, the main tube 110 has an inlet formed in a circular cross section, but is formed in an elliptical cross section at a position 100y branched into the branch tubes 121 and 122, and the branch tube 121 It is preferable to suppress the occurrence of local stress by forming the outer surface at the location where it branches to 122) in a curved shape. Here, the outer surface of the branched position 100y may form a conical, dome, or elliptical surface.

That is, the main tube 110 has an inlet area iA whose cross-section extends in a circular shape along the axial direction from the inlet 110e. Here, the length of the entrance region may be variously determined from 30% to 90% of the total length of the main tube 110. Similarly, the first branch tube 121 and the second branch tube 122 have end regions eA whose cross-sections extend circularly from the ends 121e and 122e, respectively. Similarly, the length of the end region eA may be variously determined from 30% to 100% of the total length of the branch tubes 121 and 122.

In addition, a connection area mA to which the main tube 110 and the first branch tube 121 and the second branch tube 122 are connected is formed between the inlet area iA and the end area eA. In the connection area mA, the main tube 110 gradually changes from a circular cross-section to an elliptical cross-section, and is connected to the first branch tube 121 and the second branch tube 122 in an elliptical cross-section. Accordingly, in the position where the main tube 110 is connected to the first branch tube 121 and the second branch tube 122, the short radius of the elliptical cross section of the main tube 110 is the first branch tube 121 and the second branch tube 122 The diameter of the second branch tube 122 is the same, and the major radius of the elliptical cross section of the main tube 110 is approximately equal to the sum of the diameters of the first branch tube 121 and the second branch tube 122.

On the other hand, according to a preferred embodiment 101 of the present invention, as shown in Figs. 7 and 8A, the main tube 110 and the branch tube 120 are attached to the outer surface and the inner surface of the body for attachment. A plurality of protrusions 100a are formed as auxiliary means. As shown in the drawing, the protrusion 100a may be formed in a spherical or elliptical shape. The protrusion 100a on the outer surface assists the coupling with the concrete portion 12, and the protrusion 100a on the inner surface assists the coupling of the sheath tube and the grouting material 55 filled in the tendon distribution mechanism 100.

Meanwhile, a stress concentration preventing member 140 is coupled between the branch tubes 121 and 122 extending in different directions. That is, the stress concentration preventing member 140 is formed in a shape that fills between the outer circumferential surface of the first branch tube 121 and the outer circumferential surface of the second branch tube 122. A plate having a predetermined thickness may be fitted in a triangular pyramid shape, may be inserted in a block shape, or may be manufactured integrally with a tendon distribution mechanism. In addition, a rim 142 having a larger cross-section may be formed at the end of the stress concentration preventing member 140 in order to obtain a high resistance ability with less material. Through this, it is possible to prevent a local stress concentration phenomenon occurring in the concrete filled in the narrow space between the branch tubes 121 and 122 while the tensile force is introduced into the tendon accommodated in the branch tubes 121 and 122.

The reinforcing member 150 is, as shown in Figs. 6A and 6B, tendons passing through the first branch tube 121 and the second branch tube 122, respectively (for example, T11 and T12; T21 and T22) is formed to surround the main tube 110 at a position where they meet each other in a state in which the tensile force is introduced, and to surround the outer circumferential surface of the main tube 110 and spaced apart from each other.

That is, as shown in FIG. 5, a tendon inserted in the first branch tube 121 and a tendon inserted in the second branch tube 122 are gathered in the main tube 110 to form one tendon. For convenience, when the number and cross section of the strands inserted in the first branch tube 121 and the second branch tube 122 are the same, a tensile force (P) is introduced into the tendon at the entrance side of the main tube 110 by a tension jack. When the first branch tube 121 and the second branch tube 122, a tensile force of P/2 is introduced into the tendon.

At this time, since the first branch tube 121 and the second branch tube 122 are open by a predetermined angle (ang), the tensile force (P/2) acting on the tendon of each branch tube 121 and 122 A partial area of the main tube 110 where the tendon passing through the branch tubes 121 and 122 meets the component force P1 of 1/2 of the sine component of the spread angle ang of the branch tubes 121 and 122 ( TR) acts as a force to expand the main tube 110. Since the main tube 110 is buried in the concrete part 12, there is a possibility of damage due to a tensile stress acting on the concrete part 12 around the main tube 110 by the component force P1.

In order to prevent this, a reinforcing member 150 having a shape surrounding the circumference of the main tube 110 and the branch tubes 121 and 122 is provided over a portion of the length or more. Here, the reinforcing member 150 may be formed of a steel material, reinforcing bar, etc. having high strength or rigidity, and is formed in a cross section that resists the force to expand outside the radius of the circumferential concrete. For example, it may be formed as a closed cross section based on the cross section. For example, as shown in FIG. 8B, a rectangular cross-section may be formed, or a circular cross-section may be formed although not shown in the drawing. In some cases, the reinforcing member 150 may be formed in a spiral shape.

The reinforcing member 150 may be arranged in a plurality of rows in a form surrounding the circumference of the main tube 110, and the reinforcing members 150 forming a plurality of rows are connected in the longitudinal direction by a connector 152 to be assembled and Installation convenience and reinforcement effect can be increased.

In this way, the reinforcing member 150 and the main tube 110 are spaced apart by surrounding a partial region TR of the main tube 110 where the tendons passing through the branch tubes 121 and 122 meet each other with the reinforcing member 150. ), because the concrete placed outside of) is in a firmly fixed state, even if a force that locally expands to the main tube 110 acts by a component force (P1) by a tensile force introduced into the tendon, the reinforcing member 150 Since the component force (P1) is resisted by the internal force (R) supported by it, it is possible to prevent crack damage due to tensile stress occurring in the concrete in the expansion region (TR).

As the first tendon accommodating part (S1) and the second tendon accommodating part (S2) are formed using the tendon distribution mechanism (100, 101, ...) configured as described above, one main passage is divided into two or more branches. It is possible to obtain the effect of more easily configuring the structure branching into the passage.

That is, the first tendon receiving portion (S1) is, by using the tendon distribution device 100 disposed at one end (E1) and the other end (E2) of the concrete part 12, respectively, to one end and the other end of the concrete part 12 The main passage 110p formed by the main tube 110 of the arranged tendon distribution device 100, and the main passage 110p formed by the tendon distribution device 100 disposed at one end and the other end of the concrete part 12 It is formed by the 1st-1st branch passage and the 1st-2nd branch passage connecting) in a branched form. Here, the 1-1 branch passage is the first branch tube 121 and the 1-1 sheath tube (S11) of the tendon distribution device 100 disposed at one end (E1) and the other end of the concrete part 12, respectively. The second branch tube 122 of the tendon distribution device 100 is configured to accommodate the 1-1 tendon (T11), and the 1-2 branch passageway is disposed at one end (E1) and the other end of the concrete section 12, respectively. And a 1-2 sheath tube (S12) to accommodate the 1-2 tendon (T12).

Similarly, the second tendon accommodating portion (S2) uses the tendon distribution device 100 disposed at one end (E1) and the other end (E2) of the concrete part 12, respectively, and The main passage 110p formed by the main tube 110 of the tendon distribution device 100 disposed at the other end, and the main passage formed by the tendon distribution device 100 disposed at one end and the other end of the concrete part 12 It is formed by the 2-1 branch passage and the 2nd-2 branch passage connecting (110p) in a branched form. Here, the 2-1 branch passage is the first branch tube 121 and the 2-1 sheath tube of the tendon distribution device 100 disposed at one end (E1) and the other end (E2) of the concrete section 12, respectively. S21) to receive the 2-1 tendon (T21), and the 2nd-2 branch passageway of the tendon distribution device 100 disposed at one end (E1) and the other end (E2) of the concrete part 12, respectively. It consists of a second branch tube 122 and a 2-2 sheath tube (S22) to accommodate the 2-2 tendon (T22).

In the drawing, the configuration in which the tendon distribution device 100 is formed at both ends of the concrete part 12 is illustrated, but according to another embodiment of the present invention, the tendon distribution device 100 is only at one end of the concrete part 12 It can also be applied.

As described above, the present invention comprises a prestressed concrete girder for a bridge, including a tendon distribution mechanism (100, 101, ...) for gathering or branching tendons having two or more paths into one, so that within the concrete part 12 Even if tendons are arranged in the same amount and in the same row, the number of fixing units 90 can be significantly reduced compared to the conventional one. Through this, since it is possible to reduce the vertical gap between the fixing units 90 disposed at both ends of the concrete unit 12 compared to the conventional one, it is possible to lower the mold height (H) of the concrete girder, and the cross section of the concrete part of the steel composite girder By reducing the amount, economic feasibility can be improved.

In addition, since two or more rows of tendons are integrated into one row by the tendon distribution mechanism 100, 101, ..., it is possible to simultaneously tension the integrated one row of tendons with one jack. Through this, the time required for the prestress introduction work is shortened, and at the same time, tendons (T11, T12, T21, T22) arranged symmetrically with respect to the central axis of the abdomen of the girder section are placed in one tendon (T1, T2) at the same time tension and fixation, forming a structural system that is perfectly symmetrical of tendons with respect to the vertical axis of the cross section, as well as friction loss in tendons arranged symmetrically (for example, T11, T12; T21, T22) , Since the elastic shrinkage loss is the same, the amount of prestress introduced for each position in the longitudinal direction becomes the same to the left and right with respect to the vertical axis of the cross section, thereby obtaining an advantageous effect of preventing the lateral curvature (transverse deformation) of the concrete girder.

Moreover, since the number of times to introduce the tensile force is reduced compared to the conventional one, the prestress lost in the process of introducing the prestress to the next tendon (e.g., T1) after introducing the prestress with some tendons (for example, T2). The amount of can be reduced.

Hereinafter, the steel composite girder 2 for a bridge according to the second embodiment of the present invention to which the tendon distribution mechanism 100, 101,... configured as described above is applied will be described in detail. In describing the prestressed concrete girder 2 according to the second embodiment of the present invention, the same or similar reference numerals are assigned to the same or similar configuration and operation as in the first embodiment, and the gist of the second embodiment In order to clarify, a description thereof will be omitted.

For convenience, in the drawings, the reference number of the tendon distribution mechanism installed to accommodate the first tendon (T1) is indicated as '100A', and the reference number of the tendon distribution mechanism installed to accommodate the second tendon (T2) is indicated as '100B'. Marked.

As shown in Fig. 10, the PSC girder 2 according to the second embodiment of the present invention has cutouts 14z formed below the cross-sectional neutral axis of both ends of the concrete part 12, so that the PSC girder 2 is It is different from the configuration of the first embodiment in that it is possible to obtain the effect of lowering the mold height by the height of the cutout portion 14z in the state of being mounted on an abutment or pier.

In addition, in the PSC girder 2 according to the second embodiment of the present invention, the second tendon T2 is branched into the 2-1 tendon (T21) and the 2-2 tendon (T22) at one end (E1), The other end E2 differs from the configuration of the first embodiment in that the branched 2-1 tendons T21 and 2-2 tendons T22 do not merge and are fixed respectively. Likewise, the first tendon T1 is branched to the 1-1 tendon (T11) and the 1-2nd tendon (T12) at the other end (E2), but the 1-1 tendon (T11) branched at the end (E1). And the 1-2 tendons T12 are not combined and are respectively fixed.

More specifically, as in the first embodiment described above, the second tendon T2 is the second tendon of the concrete part 12 from the 2-1 settling height H21 of the one end E1 of the concrete part of the PSC girder 1. It is disposed in the second tendon accommodating part S2 while forming a gentle curvature to the lowermost fixing part located at the 2nd-2nd fixing height H21 of the other end E2. That is, the second tendon (T2) is arranged in a form downward from the fixing part 90 located at the 2-1 fixing height (H21) of the one end (E1) of the PSC girder (1) to the center of the span. It passes through the concrete section of the lower flange, which is the lower edge of the neutral axis. In addition, the second tendon (T2) is arranged at a certain height from the center of the span of the PSC girder (1) to the other end (E2) of the girder, or is arranged upward or downward with a gentle slope to the second end of the concrete part (E). -2 It extends to the lowest fixing part located at the fixing height (H22). Here, the fixing part 90 located at the 2-2 fixing height H22 is formed in the cut-out part 14z including the lower side of the cross-sectional neutral axis of the concrete part 12.

That is, the second tendon (T2) is formed in the form of a single strand of strands in the fixing portions 90 at both ends of the concrete part 12, but as shown in FIG. 11, the 2-1 tendon (T21) and the second tendon (T21) The 2-2 tendon (T22) is divided into two strands of strands, and is built to be symmetrically arranged in the concrete part 12 while forming different rows on both sides of the abdomen 14b based on the cross-sectional central axis (Cx).

To this end, the second tendon receiving portion S2 is a 2-1 sheath tube (S21) in the first branch tube (121 in FIG. 4) and the second branch tube (122 in FIG. 4) of the tendon distribution device 100B. ) And the 2-2 sheath tube (S22) are formed to be connected, so that the 2-1 tendon (T21) and the 2-2 tendon (T22) in which one strand of strands are branched are separated from each other. It is formed to branch into the first branch passage and the second second branch passage. That is, the 2-1 branch passage is made of the first branch tube (121 in Fig. 4) and the 2-1 sheath tube (S21) of the tendon distribution device 100B, and the second second branch passage is a tendon distribution device. It consists of a second branch tube of (100B) (122 in Fig. 4) and a 2-2 sheath tube (S22).

Here, the second tendon (T2) is the 2-1 tendon (T21) and the 2-2 tendon (T22), and the same number of steel wires having the same cross-section is equally distributed, so that the 2-1 tendon (T21) and the second tendon (T21) -2 The amount of prestress introduced by tendon (T22) is introduced evenly.

The 1st tendon (T1) is the 1st 1st fixing height of the 1st end (E1) of the concrete part 12 from the fixing part 1-2 fixed position (H12) of the other end (E2) of the concrete part of the PSC girder (1) It is disposed in the first tendon accommodating part S1 while forming a gentle curvature to the lowermost fixing part located at (H11). That is, the first tendon (T1) is arranged in a form downward from the fixing part 90 located at the 1-2 fixing height (H12) of the other end (E2) of the PSC girder (1) to the center of the span. It passes through the concrete cross section of the lower flange of the neutral axis. In addition, the first tendon (T1) is arranged at a certain height from the center of the span of the PSC girder (1) to the one end (E1) of the girder, or is arranged upward or downward with a gentle slope, so that the 1-1 of the end (E1) It extends to the lowermost fixing part located at the fixing height H11. Here, the fixing portion 90 of the 1-1st fixing height H11 is formed in the cutout portion 14z including the lower side of the cross-sectional neutral axis of the concrete portion 12.

That is, the first tendon T1 is formed in the form of a single strand of strands in the fixing portions 90 at both ends of the concrete part 12, but as shown in FIG. 11, the 1-1 tendon T11 and the first tendon T11 It is divided into two bundles of strands of 1-2 tendons (T12) to form different rows on both sides of the abdomen (14b) with respect to the central axis (Cx) of the cross section, and is installed to be symmetrically arranged in the concrete part (12).

To this end, the first tendon accommodating part S1 is a 1-1 sheath tube S11 in the first branch tube (121 in FIG. 4) and the second branch tube (122 in FIG. 4) of the tendon distribution device 100A. ) And the 1-2 sheath tube (S12) are formed to be connected, so that the 1-1 tendon (T11) and the 1-2 tendon (T12) from which one strand of strands are branched are respectively separated from each other. -It is formed to branch into the first branch passage and the first second branch passage. That is, the 1-1 branch passage is made of the first branch tube (121 in Fig. 4) and the 1-1 sheath tube (S11) of the tendon distribution device 100A, and the first-2 branch passage is a tendon distribution device. It consists of a second branch tube of 100A (122 in Fig. 4) and a 1-2 sheath tube S12.

Here, the first tendon (T1) is the 1-1 tendon (T11) and the 1-2 tendon (T12), and the strands of the same cross-section are equally distributed in the same number, so that the 1-1 tendon (T11) and the first tendon (T11) -2 The amount of prestress introduced by tendon (T12) is introduced evenly.

In the drawings, unexplained reference numeral 14u is a sole plate for mounting the girder.

The PSC girder 2 according to the second embodiment of the present invention configured as described above is formed in a state where cutouts 14z are formed below the cross-sectional neutral axis of both ends of the concrete part 12, You can get the effect of lowering your sentence.

In addition, as shown in FIG. 11, the first tendon T1 is fixed in the cutout 14z of the concrete part E1, and the second tendon T1 is fixed in the cutout 14z of the other end E2 of the concrete part. As the tendon (T2) is settled, it is possible to reduce the possibility of damage at both ends of the concrete part 14 by dispersing the compressive force acting on both ends of the concrete part by the tendon (T1, T2) in the state in which the tensile force was introduced. Is obtained. In addition, by introducing a moment (BMDp) closer to the bending moment (BMDr) that actually acts on the PSC girder (2), it prevents prestress from being introduced into unnecessary parts at both ends that act small during common use, and prevents step-shaped prestress. The effect of introducing can also be obtained.

The prestressed concrete girders (1, 2) for bridges according to the present invention configured as described above are manufactured through the following processes.

Step 1 : As shown in Figs. 2 and 10, the lowermost side of one end (E1) of the concrete part 12 from a predetermined 1-2 fixing height (H12) of the other end (E2) of the concrete part 12 The first tendon accommodating part (S1) is installed to extend to the 1-1 fixing height (H11) where the fixing part is located, but at the center of the span of the girder, it is installed so as to pass through the cross section of the lower flange concrete 12c of the lower edge of the neutral axis. In addition, the first tendon receiving part (S1) and the span center part of the concrete part 12 from the 2-1 settling height (H21) of the one end (E1) of the concrete part 12 to be symmetrical in the axis direction A second tendon accommodating part S2 is installed so as to extend to a 2-2 fixing height H22 where the lowermost fixing part of the other end E2 is located.

If only the first tendon and the second tendon exist at one end and the other end of the concrete part 12, the first tendon accommodating part S1 is connected to the lowermost fixing part of the one end E1 of the concrete part 12. And the second tendon accommodating part S2 is connected to the upper fixing part of one end E1. On the contrary, the second tendon accommodating part S2 is connected to the lowermost fixing part of the other end E2 of the concrete part, and the first tendon accommodating part S1 is connected to the upper measuring part of the tartan E2.

Here, the first tendon accommodating portion (S1) and the second tendon accommodating portion (S2) may form a main passage by joining the ends of the sheath tube, and the tendon dispensing mechanisms (100, 101, ...) described above. The main passage and the branch passage may be formed by using.

If additional tendon installation is required, a third tendon accommodating portion S3 shown in FIG. 2 may be installed.

Before or after installation of the tendon receiving portions (S1, S2,...), the reinforcing bar is reinforced at the position where the concrete portion 12 is formed.

Step 2 : Before or after Step 1 is performed, a formwork (not shown) for forming the concrete part 12 is installed. As shown in Fig. 10, in the case of forming cutouts 14z below the neutral axis at one or more of both ends of the concrete part 12, the formwork is formed in a shape in which cutouts 14z are formed at both ends of the concrete part. Install.

Step 3 : Then, the unhardened concrete is poured into the formwork to cure the concrete. When the concrete is cured to sufficient strength, the formwork is removed. Accordingly, the concrete portion 12 is molded as shown in Fig. 2 or 10 in the shape of the formwork.

Step 4 : Then, the first tendon (T1) is installed in the first tendon accommodating unit, and the second tendon (T2) is installed in the second tendon accommodating unit. The tendon is installed by inserting a number of strands that make up the tendon one by one.

Step 5 : Fix the tendon in the fixing part 90 by fixing the end of the first tendon (T1) of one end (E1) of the concrete part 12 and the end of the second tendon (T2) of the other end (E2), The first tendon (T1) and the second tendon (T2) by installing a tension jack at the end of the first tendon (T1) of the other end (E2) of (12) and the end of the second tendon (T2) of one end (E1) Introduce a tensile force that pulls out sequentially.

When a tensile force is introduced into the first tendon (T1), which is a bundle, with a tension jack, the tensile force is simultaneously introduced to the 1-1 tendon (T11) and the 1-2nd tendon (T12), so the left and right asymmetry and tensile force of the tendon are introduced. A difference in the amount of prestress introduced between the left and right tendons according to the order or the like occurs, thereby preventing a conventional problem in which a transverse deformation (lateral curvature) has occurred. In other words, since two 1-1 tendons (T11) and 1-2 tendons (T12) are simultaneously tensioned with one tension jack, the tendons are perfectly symmetrical with respect to the vertical axis of the section, and when prestress is introduced into the concrete girder. It can prevent the lateral curvature that occurs in In addition, since the friction loss and elastic contraction loss of the tendons arranged symmetrically are the same, it is possible to obtain an effect that the introduction force of prestress for each position in the longitudinal direction is consistent. In addition, since the number of fixing units 90 for introducing a tensile force is reduced, it is possible to easily introduce prestress with a single tensile jack, and it is possible to obtain an effect of shortening the working time required for introducing the prestress.

Similarly, when a tensile force is introduced into the second tendon (T2), which is a bundle, with a tension jack, the tensile force is simultaneously introduced to the 2-1 tendon (T21) and the 2-2 tendon (T22), thereby suppressing the lateral curvature. In addition, it is possible to obtain the effect that the friction loss and elastic contraction loss of tendon coincide with the cross section of the prestress introduction amount for each position in the longitudinal direction.

Step 6 : When the prestress is introduced into the concrete part 12 by the tendon, as shown in Fig. 9, the grout inlet is installed in the lowermost fixing unit 91, and the grout outlet is installed in the upper fixing unit 91 Thus, grout is injected through the grout injection port to fill the inner space of the tendon receiving portion.

Since the location of the tendon anchorage is arranged with a height difference between one end and the other end of the concrete part 12, the grout can be tightly filled by the head pressure action due to the height deviation into the sheath tube during the filling process of the grout 55. have.

In the above, preferred embodiments of the present invention have been exemplarily described, but the scope of the present invention is not limited to such specific embodiments, and can be appropriately changed within the scope described in the claims. That is, the present invention includes configurations made only of some configurations of the above-described embodiments within the scope described in the claims.

For example, in the embodiment illustrated in the drawings, a girder in which the central portion is composed of a concrete portion having an I-shaped cross section is illustrated, but the present invention is not limited thereto, and may be applied to a prestressed concrete girder of various cross-sections such as a U-shaped cross-section. That is, the present invention is applicable to all of the prestressed girders for bridges that include a concrete portion extending in the longitudinal direction and prestress is introduced by a tendon. In this case, the'cross-sectional central axis' described in the specification and claims becomes a central axis transverse to the center of the left and right direction of the girder cross section as well as the abdomen of the girder in the vertical direction, and the'transverse center of gravity' described in the specification and claims The vertical section' is interpreted as a plane extending the central axis of the cross section in the longitudinal direction.

1, 2: PSC girder for bridge 12: Concrete part 55: Grout 90: Fixing part
100, 101, 100A, 100B: tendon distribution mechanism
110: main tube 110p: main passage
121: first branch tube 122: second branch tube
140: stress concentration preventing member 150: reinforcing member

Claims (13)

As a prestressed concrete girder for bridges,
A concrete part in which reinforcing bars are laid inside;
A first tendon accommodating part extending from the 1-2 fixing height of the other end of the concrete part to the 1-1 fixing height of one end of the concrete part;
A first tendon accommodated in the first tendon receiving portion and fixed in a state in which a tensile force is introduced to introduce prestress to the concrete portion;
A second tendon accommodating part extending from a 2-1 fixing height of one end of the concrete part to a 2-2 fixing height of the other end of the concrete part;
A second tendon accommodated in the second tendon accommodating portion and fixed in a state in which a tensile force is introduced to introduce prestress to the concrete portion;
It is configured to include, wherein the 2-1 fixing height at one end of the concrete part is higher than the 1-1 fixing height, and the 1-2 fixing height at the other end of the concrete part is higher than the 2-2 fixing height Prestressed concrete girders for bridges, characterized in that.
The method of claim 1,
A prestressed concrete girder for a bridge, characterized in that at least one of the 1-1 fixing height and the 2-2 fixing height is a position of the lowermost fixing part.
The method of claim 1,
The concrete part is a prestressed concrete girder for a bridge, characterized in that at least one of one end and the other end has a shape in which at least a portion of the lower side of the cross-sectional neutral axis is cut off.
The method of claim 1,
The first tendon receiving part,
One first main passage is branched into the first-first branch passage and the first-second branch passage, and the first-first tendon and the first-second tendon from which the first tendon is branched are respectively the first-first branch passages. And are accommodated in the first-second branch passage,
The first tendon receiving portion is a prestressed concrete girder for a bridge, characterized in that the horizontally symmetrically arranged with respect to the central axis of the cross-section of the concrete portion.
The method of claim 4,
The first main passage is divided in a direction in which the first-first branch passage and the first-second branch passage expand in the width direction of the concrete part, and the first-first branch passage and the first-second branch passage are Prestressed concrete girders for bridges, characterized in that they are merged back into one first main passage.
The method according to claim 4 or 5,
The first tendon receiving part,
A first branch tube installed to be buried at any one or more ends of the concrete part, respectively, and forming a part of the first-first branch passage communicating with the main passage and the main tube forming the first main passage And a tendon distribution device including a second branch tube forming a part of the first-second branch passage communicating with the main passage.
A 1-1 sheath tube connected to the first branch tube to form a remaining part of the 1-1 branch passage;
A 1-2 sheath tube connected to the second branch tube to form a remaining part of the first-2 branch passage;
Prestressed concrete girders for bridges, characterized in that configured to include.
The method of claim 6,
In a state in which a tensile force is applied to the first tendon, the first tendon accommodated in the first-first branch passage and the first-second tendon accommodated in the first-second branch passage meet each other of the main tube. A reinforcing member that surrounds the outer circumferential surface to be spaced apart while being buried in the concrete part;
Prestressed concrete girders for bridges, characterized in that configured to further include.
The method of claim 6,
Any one or more of the angle formed by the main tube and the first branch tube, and the angle formed by the main tube and the second branch tube is 2.5 to 10 degrees with respect to the axial direction of the main tube. Prestressed concrete girders for bridges.
As a method of manufacturing prestressed concrete girders for bridges,
Reinforcement reinforcement step of reinforcing reinforcement at the location where the concrete part is formed;
A first tendon receiving part is installed so as to extend from the 1-2 fixing height of the other end of the concrete part to the 1-1 fixing height of one end of the concrete part, and the other end of the concrete part from the 2-1 fixing height of one end of the concrete part Install a second tendon accommodating part at a 2-2 fixing height of, wherein the 2-1 fixing height at one end of the concrete part is higher than the 1-1 fixing height, and the 1-2 at the other end of the concrete part A tendon accommodating part installation step of installing the first tendon accommodating part and the second tendon accommodating part so that the fixing height is higher than the 2-2 mounting height;
A formwork installation step of installing a formwork for forming the concrete part;
A concrete forming step of curing concrete by pouring unhardened concrete into the formwork to form the concrete part;
In a state in which the first tendon is accommodated in the first tendon accommodating part and the second tendon is accommodated in the second tendon accommodating part, the concrete part is fixed in a state in which a tensile force is introduced into the first tendon and the second tendon. A pre-stress introduction step of introducing pre-stress to;
A grout injection step of injecting grout to the first tendon receiving portion and the second tendon receiving portion;
Method of manufacturing a prestressed concrete girder for a bridge, characterized in that configured to include.
The method of claim 9,
In the step of installing the formwork, the formwork is installed in a shape in which at least one of one end and the other end of the concrete part forms a cutout under the neutral axis;
The concrete forming step is a method of manufacturing a prestressed concrete girder for a bridge, characterized in that the concrete part is formed by pouring unhardened concrete into the formwork.
The method of claim 9,
The first tendon receiving part,
One first main passage is branched into the first-first branch passage and the first-second branch passage, and the first-first tendon and the first-second tendon from which the first tendon is branched are respectively the first-first branch passages. And are accommodated in the first-second branch passage,
The first tendon receiving portion is a method of manufacturing a prestressed concrete girder for a bridge, characterized in that the horizontally symmetrically arranged with respect to the central axis of the cross-section of the concrete portion.
The method of claim 11,
The first main passage is divided in a direction in which the first-first branch passage and the first-second branch passage expand in the width direction of the concrete part, and the first-first branch passage and the first-second branch passage are A method of manufacturing a prestressed concrete girder for a bridge, characterized in that it is recombined into one first main passage.
The method of claim 11 or 12,
The first tendon receiving part,
A main tube provided to be buried at both ends of the concrete part, the main tube forming the first main passage, and a first branch tube and the main passage forming a part of the 1-1 branch passage communicating with the main passage A tendon distribution mechanism having a second branch tube forming a part of the first-second branch passage in communication;
A 1-1 sheath tube connected to the first branch tube to form a remaining part of the 1-1 branch passage;
A 1-2 sheath tube connected to the second branch tube to form a remaining part of the first-2 branch passage;
Method of manufacturing a prestressed concrete girder for a bridge, characterized in that configured to include.

Images