KR20000055053A - Reinforcing Method Of PC Beam Bridge With Box Structure And PC Beam Bridge Having Box Reinforced Structure - Google Patents

Abstract

PURPOSE: A reinforcement method of a PC(prestressed concrete) beam bridge and a PC beam having a reinforcement structure thereof are provided to elevate the safety and the efficiency of a bridge and to lengthen the term of use. CONSTITUTION: A connecting reinforcement part(7) is formed by connecting a mechanical connecting steel reinforcing of a half slab(6) formed of precast concrete with a connecting steel reinforcing of a lower flange(4) of a PC beam. The half slab is across fixed between the lower flanges of two PC beams. Steel reinforcing concrete is grouted onto the half slab to form a reinforcement slab(9) in a certain thickness. Finally, the half slab, the reinforcement slab and the lower flanges of the PC beam are connected integrally.

Description

Reinforcing Method Of PC Beam Bridge With Box Structure And PC Beam Bridge Having Box Reinforced Structure}

The present invention relates to a method of reinforcing a prestressed concrete beam (PC beam) bridge (hereinafter referred to as a "PC beam bridge") by boxing of a mold, and a PC beam bridge having a reinforcement structure thereby. Specifically, in the PC beam bridge that requires structural reinforcement, a connection reinforcing part is provided between the lower flange parts of the two I-type PC beams to connect the lower flange parts to each other to form a mold of the PC beam bridge in the form of a box structure. The present invention relates to a method for reinforcing a PC beam bridge that reinforces the rigidity of the bridge by boxing, and a PC beam bridge having a reinforcement structure thereby.

A PC beam bridge is generally composed of a reinforced concrete upper slab loaded with an external load such as a vehicle, and one or more PC beams disposed at predetermined intervals below the upper slab to support the upper slab and form a bridge of the bridge.

In general, PC beams in which prestresses are introduced in PC beam bridges lose their initial prestress forces due to slippage of anchorage, frictional losses of prestress, creep of concrete, dry shrinkage and relaxation of concrete. The durability and stiffness of the structure is reduced. In addition, even the most precisely constructed PC beams, the prestressing force of the tension material placed inside the beams relaxes over time.

On the other hand, due to the use of bridges, the aging or the actual load is increased to cause the design load is insufficient.

As described above, when the prestressing force of the PC beam decreases and the durability and rigidity of the structure decreases, or when the bridge's design load is insufficient due to the aging of the bridge or the weight increase, the bridge needs to be reinforced in a timely manner.

As a method of reinforcing the PC beam bridge that is already installed and used, the section expansion method for expanding the cross section of the PC beam by placing concrete around the PC beam, the member expansion method for installing additional PC beams or expanding the piers, Methods such as the prestress introduction method that introduces additional prestress using PC tension material have been proposed.

However, the section enlargement method and the member expansion method have a disadvantage in that a large amount of cost is required to enlarge the section and to add a separate member, and the maintenance and reinforcement costs required by the reinforcement of the bridge become expensive, and additional prestress is introduced. The following problems are pointed out in the prestressing method.

In the conventional reinforcement method using the introduction of prestress to reinforce the PC beam by introducing an additional prestress to the existing tension material, in order to introduce the additional pre-press the anchor of the tension material must be installed at the end of the PC beam. In the PC beam bridge, however, the end of the PC beam is externally worked because the stress is concentrated in the end of the PC beam, the stress is concentrated, the rebar is concentrated, and the triaxial stress caused by the installation of the shoe is generated. Damage to the end of the PC beam in order to install the anchorage of the tension member is very risky to cause local breakdown of the end due to rupture stress or splitting stress, so that if the shoe support is broken, the mold The risk of sinking and tilting is very high. Therefore, it is very difficult to secure a working space for introducing additional prestress to the tension member.

In addition, since the tension material installed on the bridge is generally filled with grouting to protect it from the outside, it is difficult to re-tension the existing tension material to introduce additional prestress, and the cost is enormous.

In particular, in the case where the tension member is bent and the external prestress is introduced for the reasons described above, there are many difficulties in the positioning of the tension member and the direction changer of the tension member.

Therefore, there is an urgent need for a reinforcement method that can safely and effectively reinforce the rigidity of the PC beam bridge without the above problems.

The present invention was developed in order to solve the above problems of the prior art, and increases the stability and usability of the bridge by stably increasing the longitudinal bending stiffness, the lateral bending stiffness and the torsional stiffness of the PC beam bridge which is already installed and used. The present invention provides a method for reinforcing a PC beam bridge and a reinforcing structure for the PC beam bridge which can extend the service life of the bridge.

In addition, the present invention can prevent the PC beam end from being broken due to the installation of a separate tension member anchorage in the PC beam end when introducing an additional external prestress for reinforcement, and facilitates the positioning of the tension member and the direction changer It is an object of the present invention to provide a PC beam bridge having a reinforcing method and a reinforcing structure by which the external prestress for reinforcement can be introduced safely and economically and technically easily.

According to the present invention, in order to achieve the above object, by connecting the lower flanges of the neighboring PC beams of the PC beam bridges integrally with each other, the PC beam mold for supporting the upper slab of the bridge into a box structure, A PC beam bridge having a reinforcement method and thereby a reinforcement structure capable of increasing longitudinal bending stiffness, transverse bending stiffness and torsional stiffness is provided.

Specifically, in the PC beam bridge composed of a reinforced concrete upper slab loaded with an external load and a plurality of PC beams disposed at a predetermined interval below the upper slab to support the upper slab and form a bridge of the bridge, Reinforcing rigidity of the bridge by forming a connection reinforcement portion made of reinforced concrete slab between the lower flange portion for any two PC beams to form a cross-sectional structure of the box-shaped closed bottom portion A method of reinforcing a PC beam bridge by boxing a mold is provided.

In addition, as an embodiment of the reinforcing method according to the present invention, the connecting reinforcing part, by connecting the mechanical joint reinforcing bar of the half slab made of precast concrete with the connecting reinforcing bar of the lower flange of the PC beam to connect the half slab of the two PC beam It is produced by fastening between the lower flanges, the reinforced concrete slab of the predetermined thickness by placing the reinforced concrete on the top of the half slab to connect the half flange, the reinforcing slab and the lower flange of the PC beam integrally. There is provided a reinforcement method, characterized in that.

In another embodiment of the present invention, there is provided a reinforcement method comprising introducing a prestress by placing a tension member in the axial direction in the connecting reinforcing part, and penetrating the connecting reinforcing part and the PC beam in a perpendicular direction of the axial direction. There is also provided a reinforcement method characterized by placing a tension member and introducing prestress in the axial direction perpendicular to the joint reinforcement.

In addition, as an embodiment of the reinforcing method according to the present invention, the tension member is formed in the lower portion of the connecting reinforcement portion for forming the tension member direction, the connecting portion between the upper flange portion of the bridge end portion is placed in the tension member fixing block with the tension member fixing block Reinforcement method characterized in that it introduces an external prestress to the bridge mold, and the reinforcement method is characterized in that it is formed in only a part of the bridge span, the half slab and in-place reinforcement slab and For the connection of the half slab and the reinforcement slab joints are provided a reinforcement method characterized in that a number of shear keys are installed.

On the other hand, the PC beam bridge having a reinforcing structure according to the reinforcement method of the present invention, the reinforced concrete upper slab and the upper slab is disposed at predetermined intervals under the external load to support the upper slab to support the mold of the bridge The lower plan of any two PC beams of the plurality of PC beams by connecting a plurality of PC beams and a mechanical joint reinforcing bar made of precast concrete and connected in advance with the connecting bars of the lower flange of the PC beam. The PC beam mold is closed by a half slab fixed across the branch, and a connecting reinforcement part consisting of a reinforced slab made of reinforced concrete formed by site-casting a predetermined thickness over the half slab and integrally connecting with the lower flange part. PC beam bridge, characterized in that it has a reinforcing structure converted into a box-shaped cross-sectional structure This is provided.

1 is a schematic cross-sectional view of a bridge beam perpendicular to a PC beam bridge having a reinforcement structure according to the reinforcement method of the present invention.

FIG. 2 is a detailed view of the connecting reinforcement part indicated by A in FIG. 1;

3 is an embodiment in which the tension member is bent and arranged to introduce external prestress in the axial direction;

4 is another embodiment in which the tension member is bent and arranged to introduce external prestress in the axial direction;

5 is a detailed side view of the tension material direction conversion block as a detailed view of the portion B of FIG.

FIG. 6 is a schematic cross-sectional view of a PC beam bridge having a reinforcing structure according to the reinforcing method of the present invention provided only in an outer mold, in a direction perpendicular to the bridge axis;

7 is a schematic view of an embodiment in which the connecting reinforcing portion is provided only in a part of the mold in the axial direction.

Explanation of symbols on the main parts of the drawings

1: upper slab 2: PC beam

3: upper flange portion 4: lower flange portion

5: abdomen 6: cupping part

7: connection reinforcement unit 8: half slab

9: reinforcing slab 10: mechanical joint rebar

Next, the configuration of the present invention will be described in detail with reference to FIGS. 1 to 7.

1 is a schematic cross sectional view of a PC beam bridge having a reinforcing structure according to the reinforcing method according to the present invention in a crosswise direction. 1 shows an embodiment in which a reinforcement structure according to the reinforcement method of the present invention is formed between two PC beams 2 at the center of a bridge. PC beam bridge is one of the reinforced concrete upper slab (1) that is subjected to external load, such as a vehicle, and at least one PC beam arranged at a predetermined interval in the lower portion of the upper slab 1 to support the upper slab (1) to form a bridge of the bridge It consists of (2).

The PC beam 2 is composed of an I-type prestressed concrete beam (PC beam), and is composed of an upper flange portion 3, a lower flange portion 4, and an abdomen 5 connecting them to each other. In applying the reinforcing method according to the present invention, it is to form a chipping portion 6 in the lower flange portion 4 to improve the adhesion of the adhesive surface between the connecting reinforcement portion and the flange portion described later. desirable. The size of the chipping portion 6 is preferably about 7 mm, but is not necessarily limited thereto, and may be appropriately selected according to the size of the PC beam, the size of the flange portion, and the size of the bridge. In addition, the PC beam does not necessarily have to be type I, and may be a PC beam having a cross-sectional shape other than the type I PC beam. In this case, the lower flange portion referred to herein will refer to the lower end of the PC beam.

Figure 2 is for explaining in detail the reinforcing structure according to the present invention, it is a detailed view of the reinforcing structure represented by A in FIG. As shown in FIG. 2, in the reinforcement method according to the present invention, a connecting reinforcement part 7 is formed between the lower flange parts 4 to connect the lower flange parts 4 of neighboring PC beams. The connecting reinforcement portion 7 is composed of a half slab (8) made of precast concrete and a reinforcement slab (9) made of site-cast concrete integrally cast on the half slab (8). do.

The half slab 8 is made of precast concrete, and is manufactured by embedding the mechanical joint reinforcing bar 10 when the half slab 8 is manufactured to be connected to the lower flange 4 of the PC beam. In the reinforcement method according to the present invention, since the factory-made precast reinforced concrete half slab 8 is used, there is no need to use a separate formwork or clubb when installing the reinforcement slab, which will be described later. The construction cost and time can be saved.

Looking at the manufacturing method of the connection reinforcement part 7 in detail, first, prefabricated half slab (8) made in the factory is placed between the lower flange portion 4 of the PC beam to be installed, and welding or separate reinforcement Connection bars 11, such as grip bars, which are anchored to the mechanical joint reinforcement 10 of the half slab 8 and the lower flange 4 of the PC beam, using the drinking mechanical joint 21. ) Are connected to each other, and the half slab 8 is installed between the PC beams.

For a more complete connection of the half slab 8 and the lower flange part 4, a predetermined spacing 12 is formed between the side of the half slab 8 and the lower flange part 4, and the cast-in-place concrete is placed in this gap. It is also possible to complete the connection between the half slab 8 and the lower flange 4 of the PC beam by filling the gap 12 with a sealing material such as epoxy or a sealable and adhesive strength having a predetermined adhesive strength. .

Above the half slab (8) to install the reinforcement slab (9) by placing the reinforced concrete in the field. It is also preferable to provide a plurality of shear keys 13 on the upper surface of the half slab 8 for joining the half slab 8 and the reinforcing slab 9. The size, shape and number of installations of the shear key 13 are determined according to the shear force acting on the joints of the half slab 8 and the reinforcing slab 9. If the shear stress of concrete is less than the allowable shear stress, it is preferable to reinforce the shear reinforcement bars or install steel bars in the vertical direction.

In the reinforced concrete reinforcement slab 9 which is cast in the field on the half slab 8, an axial tension member 14 made of strand and / or steel rod in the axial direction is installed to introduce prestress in the axial direction to connect the reinforcement portion 7. It is possible to further reinforce the rigidity of the bridge, and depending on the design conditions of the bridge, as shown by the member number 15, it is made of a stranded wire and / or steel rod in the direction perpendicular to the bridge through the reinforcing slab 9 and the PC beam 2 It is also preferable to provide the tension member 15 in the perpendicular direction of the throttle to introduce and reinforce the prestress in the perpendicular direction of the axial direction.

According to the reinforcement method according to the present invention when connecting the lower flange portion 4 of the two PC beams to the connecting reinforcement portion 7, the structural structure of the bridge consisting of only the PC beam structure of the box structure form Converted to the mold, the longitudinal and transverse bending stiffness is increased compared to the bridge before reinforcement, as well as the torsional stiffness is significantly increased.

In addition, when the mold of the existing PC beam bridge is converted into a box mold according to the reinforcement method of the present invention, the structural analysis of the bridge can be performed using the design method and analysis method of the PC box girder bridge, and thus the longitudinal direction and It is easy to develop a design program that can design the shape of the cross section.

On the other hand, in the PC beam bridge provided with the reinforcing structure according to the reinforcement method according to the present invention, as described later, if necessary, according to the structural analysis results of the entire bridge, tension members such as strands or the like in a straight line or straight lines are arranged in the axial direction. Additional external prestress can be introduced for the bridge mold. This will be described in detail below.

3 and 4 schematically show an embodiment in which the tension member is bent and arranged to introduce external prestress in the axial direction. The embodiment of FIG. It is an Example which makes / 4 point a bending point, and the Example of FIG. 4 is an Example which makes a half point of the whole span the bending point.

3 and 4, the tension member 22 may be bent to introduce additional external prestress, and the external prestress may be introduced in the axial direction. In this case, the tension member 22 may be changed to change the direction of the tension member 22. The direction conversion block 16 is integrally installed in the connecting reinforcement unit 7. As shown in FIG. When the connecting reinforcement portion 7 is installed for the entire span in the mold direction of the bridge, the tension member direction conversion block 16 is integrally formed on the upper surface of the connecting reinforcement portion 7, that is, reinforcement concrete 9, As will be described later, when the connecting reinforcing portion 7 is formed only at the bent portion of the tension member, the tension member direction conversion block 16 is integrally formed on the lower surface of the half slab 8. 3 and 4 show the shape in which the tension material direction conversion block 16 is installed on the upper surface of the connecting reinforcing portion 7. The installation position of the block 16 is provided on the upper or lower surface of the connecting reinforcing portion depending on the arrangement shape of the external tension member and the installation position of the connecting reinforcing portion in the mold of the bridge as described later.

FIG. 5 is a detailed view of part B of FIG. 3, showing a side view of the tension member direction conversion block 16, wherein the tension material passage hole 17 has a tension member 22 in the tension material direction conversion block 16. It is formed in accordance with the conversion direction. In order to reinforce the block itself, it is preferable that reinforcing bars are arranged inside the block 16. As the tension member 22 for introducing the prestress in the axial direction is disposed through the hole 17 of the block 16, the direction is converted and bent in the axial direction as shown in FIGS. 3 and 4. .

On the other hand, when the external prestress in the axial direction is introduced, the fixing block 20 for fixing the tension member 22, as shown in Figs. 2, 3 and 4, the upper flange portion 3 of the neighboring PC beam It is mounted on the connecting portion (18) between. The specific configuration of the fixing block 20 may be appropriately designed according to the prior art according to the size of the prestress, the thickness of the tension member, the tension method and the like introduced in the axial direction. In addition to the bending and arranging the tension member as described above, it is also possible to arrange in a straight line. In case of introducing external prestress, consideration should be given to reinforcement in the direction perpendicular to the throttle, to the bending state of the tension member and to the arrangement of the cross beams.

On the other hand, in order to reinforce the prestress due to the tension material arranged in the axial direction, it is also preferable to install a cross beam in the axial direction perpendicular to the abdomen of the neighboring PC beam (2).

In PC beam bridges, the lanes through which heavy weight vehicles pass are concentrated in the center of the bridge, the curvature of the bridge surface, the degree of flatness of the pavement, the lateral distribution of the load, and the angle of inclination in the case of social bridges. It may be necessary to reinforce only a part of the inside or a part of the outside of the bridge. In this case, the connecting reinforcement portion according to the reinforcement method of the present invention may be formed only on the outer mold of the bridge or only on the inner mold of the bridge, and the installation position of the connecting reinforcement portion may be set according to the load generation position such as the maximum moment in the bridge direction of the bridge. It can be different.

Fig. 6 is an open cross-sectional view of the PC beam bridge in a cross axial direction, in which connection reinforcing portions 7 are formed between the flange portions of two neighboring PC beams outside the bridge so that the outer molds are all in the form of a box structure. A transformed embodiment is shown. An embodiment in which a connecting reinforcement 7 is formed only between the lower flange portions of two PC beams located in the center of the cross section of the bridge so that only the inner mold is box structured and reinforced is shown in FIG. 1. On the other hand, it is also possible to form the entire bridge in the form of a box by connecting the connection reinforcing portion 7 is formed between all the PC beams as shown in the embodiment shown in Figs.

As described above, according to the reinforcement method according to the present invention, since the reinforcing structure, that is, the connecting reinforcing portion can be installed only in a part of the mold, it is possible to locally reinforce only the portion that requires reinforcement.

In the following, various embodiments in which the position is converted to the box structure by the connection reinforcement in the axial direction will be described.

First, according to the reinforcement method of the present invention, a link reinforcement part 7 is provided for the entire span in the bridge axial direction with respect to two PC beams 2 adjacent to each other, and the mold is box-structured for the entire span in the axial direction. can do. However, according to the reinforcement method of the present invention, it is also possible to box only a part of the mold by connecting connection reinforcement only at the point where the maximum moment occurs for the span of the entire bridge. In addition, the construction period and reinforcement cost of bridge reinforcement can be reduced.

Specifically, as described with reference to FIGS. 3 and 4, when the tension member is bent and additionally introduced to the external prestress in the axial direction of the bridge, there is also a method of reinforcing the connecting reinforcement part only at the point where the tension member is bent.

In detail, as illustrated in FIG. 3, when the 1/4, 2/4, and 3/4 points of the bridge span are defined as bending points, the connecting reinforcement part 7 has 1/1 at which the bending points are located. It is possible to form the maximum resistance moment by the external prestress at this point by forming the mold by forming a predetermined width only at the 4 points, the 2/4 points, and the 3/4 points, as shown in FIG. When the half point of the bridge span is used as a bending point, the reinforcing effect can be maximized by placing the connection reinforcement part 7 having a predetermined width only in the bent portion. In some cases, only the part where the cross beam is installed may be formed by forming a connection reinforcing part. FIG. 7 illustrates an embodiment in which only a part of the mold is reinforced in the bridge axial direction. In FIG. 7, an end portion of the bridge in which a tension block fixing block 20 is formed and a tension block conversion block 16 are provided. The embodiment in which the connection reinforcing portion 7 is formed only at the bent portion is formed. In FIG. 7, the part indicated by the reference numeral 19 indicates the opening 19 in which the connecting reinforcement 7 is not formed in the mold of the bridge.

On the other hand, in general, the torsional moment is the maximum value at the point, and the bending moment is the maximum value at the center of the bridge span, so that the connecting reinforcement is formed only at the point and the center of the bridge to be boxed, and the rest is opened. It is also possible to configure.

As described above, according to the reinforcement method of the present invention, the connecting reinforcement part may be provided for the span of the entire bridge in the axial direction to box the mold of the entire bridge, and the portion where the maximum moment or shear force is generated according to the structural analysis of the bridge. It is also possible to box only some of the molds of the bridge by installing connecting reinforcements only on parts of the bridge, such as those requiring special reinforcement. The site to be boxed can be appropriately selected according to the structural analysis of the bridge.

In general, when the external prestress is introduced into an existing bridge, splitting stress, bursting stress, etc. are generated by the tension load at the portion where the tension member is bent, and a significant magnitude of stress is applied to the structure. In the present invention, by forming a connection reinforcing portion at the lower end of the portion where the tension material is bent to box the PC beam, it is possible to stably transfer the upward force due to the strained tension material to the mold without strain.

The reinforcement method of the present invention described above is not only applied to simple bridges or continuous bridges of road bridges and railway bridges, but can also be applied to bridges, bridges, curved bridges, long bridges, or composite bridges by a factory-made block method.

According to the present invention, the lower flanges of the neighboring PC beams of the PC beam bridges are integrally connected to each other by connecting reinforcing portions so that the PC beam molds for supporting the upper slabs of the bridges are formed in a box structure, and thus the longitudinal direction of the bridges. The PC beam bridge can be reinforced to increase the flexural rigidity, the transverse flexural rigidity and the torsional rigidity.

Therefore, the PC beam bridge having the reinforcement structure according to the reinforcement method of the present invention has increased longitudinal bending stiffness, lateral bending stiffness and torsional stiffness of the bridge compared to the bridge before reinforcement, thereby increasing the stability and usability of the bridge. The age of use is also extended.

Further, according to the reinforcement method of the present invention, it is possible to reinforce the PC beam bridge by introducing an additional external prestress, and in particular, since the tension member direction conversion block and the tension member fixing block can be easily installed separately in an appropriate position. In comparison with the additional external prestress is very easy, it can be made easy to introduce the prestress by bending the tension member.

In addition, the present invention can prevent the PC beam end from being broken due to the installation of a separate tension member anchorage in the PC beam end when introducing an additional external prestress for reinforcement, and facilitates the positioning of the tension member and the direction changer This makes it possible to introduce external prestresses for reinforcement safely, economically and technically easily.

In addition, the reinforcement method according to the present invention can select and reinforce only a portion that requires reinforcement, such as where the maximum moment occurs in the axial direction and the perpendicular direction of the axial direction, or where the stress is concentrated by the tension member. The cost can be optimized.

As described above, the present invention has been described in relation to an embodiment, and the scope of the present invention is not limited thereto, and the scope of the invention will be defined only by the claims.

Claims (8)

Reinforced concrete upper slab (1) loaded with an external load, and a plurality of PC beams (2) disposed at a predetermined interval below the upper slab (1) to support the upper slab (1) and form a bridge of the bridge In a PC beam bridge, a connecting reinforcement part 7 made of reinforced concrete slab is formed between the lower flange part 4 for any two PC beams to make the PC beam mold into a box-shaped cross-sectional structure with the lower part closed. A method of reinforcing a PC beam bridge by boxing a mold, characterized by reinforcing the rigidity of the bridge. 2. The harness according to claim 1, wherein the connecting reinforcement part 7 connects the mechanical joint reinforcing bar 10 of the half slab 6 made of precast concrete with the connecting reinforcing bar of the lower flange part 4 of the PC beam. The slab 6 is fixed across the lower flanges 4 of the two PC beams, and the reinforced concrete slab 9 is formed on-site over the half slab 6 to form a reinforcement slab 9 of a predetermined thickness. Reinforcing method characterized in that it is produced by integrally connecting the slab (6) and the reinforcing slab (9) and the lower flange portion of the PC beam. The reinforcement method according to claim 1 or 2, characterized in that a prestress is introduced by placing a tension member (14) in the axial direction in the connecting reinforcement portion (7). The prestress is introduced in the axially orthogonal direction of the connection reinforcement part according to claim 1 or 2, wherein a tension member (15) is provided through the connection reinforcement part (7) and the PC beam (2) in the axial orthogonal direction. Reinforcement method characterized in that. The tension reinforcing block (7) is formed in the connecting reinforcing portion (7), and the tension fixing member (20) is provided in the connecting portion (18) between the upper flange portions of both ends of the bridge. And reinforcing the tension member (22) in the axial direction to introduce an external prestress to the bridge mold. The reinforcement method according to claim 1 or 2, characterized in that the connecting reinforcement part (7) is formed only in a part of the mold in the axial direction of the bridge. The method according to claim 2, characterized in that a plurality of shear keys are provided at the joint portion between the half slab 6 and the reinforcing slab 9 for the connection between the half slab 6 and the in situ reinforcing slab 9. Reinforcement method. Reinforced concrete upper slab (1) loaded with external load, A plurality of PC beams (2) disposed at predetermined intervals below the upper slab (1) to support the upper slab (1) and form a bridge of a bridge; The mechanical joint reinforcing bar 10, which is made of precast concrete and is embedded in advance, is connected to the connecting bar of the lower flange 4 of the PC beam, so that any two PC beams of the plurality of PC beams 2 The lower flange part consists of a half slab 6 fixed across the lower flange part 4 and a reinforcement slab 9 made of reinforced concrete formed by field casting to a predetermined thickness over the half slab 6. PC beam bridge, characterized in that it comprises a reinforcing structure consisting of a connecting reinforcing portion (7) to connect integrally, the PC beam mold is converted into a closed box-shaped cross-sectional structure.