A type of asymmetric cross-section box girder for both road and rail transport.

Abstract

This application relates to an asymmetrical cross-section box girder for both highway and railway on the same level, comprising: a highway-concrete composite beam and a railway steel box girder. The highway-concrete composite beam includes steel beams arranged along the longitudinal direction of the bridge and a concrete bridge deck at the top of the steel beams. The railway steel box girder is arranged along the longitudinal direction of the bridge and is located on one side of the highway-concrete composite beam. In this invention, the highway side is a steel-concrete composite beam. The concrete bridge deck at the top of the steel beams increases the stiffness and stability of the main beam while also increasing the self-weight of the highway-side beam. This arrangement results in the first constant load per meter in the transverse direction of the highway side being greater than that of the railway side. Because the second constant load of the highway is less than that of the railway, by appropriately adjusting the second constant load of the highway and railway, as well as the thickness of the bridge deck of the composite beam, it is possible to achieve a sum of the first and second constant loads per meter in the transverse direction of the highway-side composite beam equal to the sum of the first and second constant loads per meter in the transverse direction of the railway-side steel box girder. This ensures that the center of gravity of the main beam section is located on the transverse centerline under dead load, thereby eliminating the eccentric loading effect caused by the asymmetrical arrangement of the highway and railway.

Description

Technical Field

[0001] This application relates to the field of bridge structure technology, and in particular to an asymmetric cross-section box girder with both road and rail transport on the same floor. Background Technology

[0002] With the rapid development of high-speed railways, many long-span bridges in China have begun to adopt main beams with an asymmetrical arrangement of road and rail lines on the same level. This type of main beam can avoid the intersection of road and rail lines at both ends of the bridge, improve space utilization, and may significantly reduce the investment in connecting lines when applied to some mountainous areas or urban centers, thereby reducing the total investment in the project.

[0003] Currently, long-span cable-stayed bridges with asymmetrical layouts of railway and highway cables on the same level often employ main girder sections that are basically symmetrical from left to right. In this arrangement, the first dead load on the railway side is the same as the dead load on the highway side. However, the second dead load on the railway side is generally greater than that on the highway side. Therefore, under the combined action of the first and second dead loads, the dead load on the railway side of the main girder is greater than that on the highway side. This leads to lateral eccentric load effects, such as torsion of the main girder and lateral bending moments in the bridge towers and their foundations. The structural system suffers from complex stress and poor economic efficiency. To ensure that the main girder alignment meets the specifications, torsion can be eliminated by adding weight on the highway side or increasing cable tension on the railway side. However, adding weight on the highway side only increases the weight of the main girder and does not improve structural strength, thus increasing project investment. Increasing cable tension on the railway side only solves the torsion problem of the main girder but does not address the lateral stress problem of the bridge towers and their foundations, resulting in poor economic efficiency for the main towers and their foundations. Summary of the Invention

[0004] This application provides a box girder with an asymmetrical cross-section for both railway and highway transport on the same floor, which can solve the problem of lateral eccentric load effect caused by the railway side dead load being greater than the highway side dead load in related technologies.

[0005] This application provides an asymmetrical cross-section box girder for both highway and railway lines, comprising: a highway composite beam and a railway steel box girder. The highway composite beam includes a steel beam and a concrete bridge deck disposed on top of the steel beam, both arranged along the longitudinal direction of the bridge. The railway steel box girder is arranged along the longitudinal direction of the bridge and is disposed on one side of the highway composite beam. The highway side is a steel-concrete composite beam, meaning a concrete bridge deck is disposed on top of the steel beam, while the railway side is a steel box girder. This arrangement results in a greater weight per meter in the constant transverse direction on the highway side compared to the railway side. Because the dead load of highways is less than that of railways, by appropriately adjusting the thickness of the dead loads of highways and railways, as well as the deck thickness of the combined beam bridge, the sum of the first and second dead loads per meter of the combined beam on the highway side in the transverse direction can be made equal to the sum of the first and second dead loads per meter of the steel box girder on the railway side. This ensures that the center of gravity of the main beam section is located on the transverse centerline under dead load, eliminating the eccentric load effect caused by the asymmetrical arrangement of highways and railways. The concrete deck of the steel-concrete combined beam on the highway side not only increases the weight of the main beam on the highway side, but also fully utilizes the compressive strength of concrete and the tensile strength of steel beams by integrating with the steel beams to share the load. Compared with pure steel beams, this improves the stiffness and stability of the main beam, reduces the amount of steel used, and has good economic benefits. Compared with the main beams arranged in layers for highways and railways, the bridge deck elevation of the combined beam on the highway and the steel box girder on the railway is lower, which has the advantages of shorter approach bridge length, smaller slope, smaller land area, and lower total project investment.

[0006] In some embodiments, the steel beam includes an upper flange and a first bottom plate, and a first web and a second web are disposed between the first bottom plate and the upper flange along the longitudinal direction of the bridge.

[0007] In some embodiments, the first base plate includes a first inclined base plate and a first flat base plate; one end of the first inclined base plate is connected to the first flat base plate, and the other end is connected to the first web plate, and the other end of the first flat base plate is connected to the second web plate.

[0008] In some embodiments, the upper flange includes a first upper flange and a second upper flange, wherein the first upper flange is disposed at the top end of the first web and the second upper flange is disposed at the top end of the second web.

[0009] In some embodiments, a plurality of first transverse diaphragms are arranged at intervals along the longitudinal direction of the bridge between the first web and the second web.

[0010] In some embodiments, the upper flange further includes a third upper flange disposed on top of the first diaphragm, the third upper flange being located between the first upper flange and the second upper flange.

[0011] In some embodiments, the steel beams and the concrete bridge deck are connected by shear connectors. The concrete bridge deck of the highway composite beam not only increases the weight of the main highway beams but also integrates with the steel beams through shear connectors to share the load, fully utilizing the compressive strength of concrete and the tensile strength of steel beams. Compared to pure steel beams, this improves the stiffness and stability of the main highway beams, reduces steel consumption, and has good economic benefits.

[0012] In some embodiments, the railway steel box girder includes: a top plate, a second bottom plate, and a second transverse diaphragm; a third web is provided between the second bottom plate and the top plate; the second bottom plate includes a second inclined bottom plate and a second flat bottom plate connected to the second inclined bottom plate; the second transverse diaphragm is arranged longitudinally between the top plate and the second bottom plate.

[0013] In some embodiments, a force-transferring member is provided between the highway composite beam and the railway steel box girder.

[0014] In some embodiments, the force-transmitting component includes: a first stiffening rib, a second stiffening rib, and a bearing plate. The first stiffening rib is connected to the highway composite beam; the second stiffening rib is connected to the railway steel box girder; the bearing plate is connected between the first stiffening rib and the second stiffening rib, with one end connected to the highway composite beam and the other end connected to the railway steel box girder. By providing the first stiffening rib, the second stiffening rib, and the bearing plate, the transverse inward force between the top plate of the railway steel box girder and the concrete bridge deck can be effectively and smoothly transferred, allowing the railway steel box girder and the highway composite beam to form a unified whole in the transverse direction and share the load. A second shear connector is provided on the first stiffening rib, and the first stiffening rib and the concrete bridge deck are connected by the second shear connector. The function of the second stiffening rib is to uniformly transfer the transverse inward force of the top plate of the railway steel box girder to the bearing plate, and then further transfer the internal force to the concrete bridge deck through the bearing plate and the first stiffening rib.

[0015] In some embodiments, vents are installed on both sides of the asymmetrical cross-section box girder on the same floor as the railway and highway. Installing vents improves the aerodynamic performance of the asymmetrical cross-section box girder and enhances its wind resistance stability.

[0016] The beneficial effects of the technical solutions provided in this application include:

[0017] This application provides an asymmetrical cross-section box girder for both highway and railway on the same level. The railway side is a steel box girder, and the highway side is a steel-concrete composite beam. This means a concrete bridge deck is installed at the top of the steel beam. While improving the stiffness and stability of the main girder, this also increases the self-weight of the highway-side beam. This arrangement results in the weight per meter of the highway-side dead load in the transverse direction being greater than that on the railway side. Because the second dead load of the highway is less than that of the railway, by appropriately adjusting the thickness of the highway and railway dead loads and the composite beam bridge deck, the sum of the first and second dead loads per meter of the highway-side composite beam in the transverse direction can be made equal to the sum of the first and second dead loads per meter of the railway-side steel box girder in the transverse direction. This ensures that the center of gravity of the main girder section is located on the transverse centerline under dead load, eliminating the eccentric loading effect caused by the asymmetrical arrangement of the highway and railway.

[0018] This application provides an embodiment of an asymmetrical cross-section box girder for both highway and railway on the same floor. The concrete bridge deck of the steel-concrete composite beam on the highway side not only increases the weight of the main beam on the highway side, but also fully utilizes the compressive strength of the concrete bridge deck and the tensile strength of the steel beam by integrating with the steel beam to share the load. Compared with pure steel beams, it improves the stiffness and stability of the main beam, reduces the amount of steel used, and has good economic benefits. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A front view of the overall structure provided for an embodiment of this application;

[0021] Figure 2 The overall structural plan view provided for the embodiments of this application;

[0022] Figure 3 for Figure 2 Sectional view of AA in the middle;

[0023] Figure 4 for Figure 2 Cross-sectional view of the middle section (BB);

[0024] Figure 5 A front view of the overall structure provided for an embodiment of this application.

[0025] In the diagram: 1. Highway composite beam; 10. Steel beam; 100. First upper flange; 101. Second upper flange; 102. Third upper flange; 103. First web; 104. Second web; 105. First inclined bottom plate; 106. First flat bottom plate; 107. First diaphragm; 11. Concrete bridge deck; 12. First shear connector;

[0026] 2. Railway steel box girder; 20. Top plate; 21. Third web plate; 22. Second inclined bottom plate; 23. Second flat bottom plate; 24. Second transverse diaphragm;

[0027] 3. Force transmission component; 30. First stiffening rib; 31. Bearing plate; 32. Second stiffening rib; 33. Second shear connector;

[0028] 4. Air nozzle. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0030] See Figures 1 to 5 This application provides an asymmetrical cross-section box girder for both railway and highway transport, which can solve the problem of lateral eccentric load effect caused by the railway side dead load being greater than the highway side dead load in the main girder in related technologies.

[0031] With the rapid development of high-speed railways, many long-span bridges in China have begun to adopt main beams with an asymmetrical arrangement of road and rail lines on the same level. This type of main beam can avoid the intersection of road and rail lines at both ends of the bridge, improve space utilization, and may significantly reduce the investment in connecting lines when applied to some mountainous areas or urban centers, thereby reducing the total investment in the project.

[0032] Currently, long-span cable-stayed bridges with asymmetrical layouts of railway and highway cables on the same level often employ main girder sections that are basically symmetrical from left to right. In this arrangement, the first dead load on the railway side is the same as the dead load on the highway side. However, the second dead load on the railway side is generally greater than that on the highway side. Therefore, under the combined action of the first and second dead loads, the dead load on the railway side of the main girder is greater than that on the highway side, leading to torsion in the main girder. This results in lateral eccentric loads such as bending moments in the bridge towers and their foundations, causing complex structural stresses and poor economic efficiency. To ensure that the main girder alignment meets the specifications, torsion can be eliminated by adding weight on the highway side or increasing cable tension on the railway side. However, adding weight on the highway side only increases the weight of the main girder and does not improve structural strength, thus increasing project investment. Increasing cable tension on the railway side only solves the torsion problem of the main girder but does not solve the lateral stress problem of the bridge towers and their foundations, resulting in poor economic efficiency for the main towers and their foundations.

[0033] To address the issue of lateral eccentric loading effect in the main girder due to the railway side dead load being greater than the highway side dead load, this application provides an asymmetrical cross-section box girder with both highway and railway on the same level. The box girder includes a highway-connected beam 1 and a railway steel box girder 2. The highway-connected beam 1 includes a steel beam 10 and a concrete bridge deck 11 disposed at the top of the steel beam 10. Both the steel beam 10 and the concrete bridge deck 11 are arranged along the longitudinal direction of the bridge. The railway steel box girder 2 is arranged along the longitudinal direction of the bridge and is disposed on one side of the highway-connected beam 1, forming an integral structure that shares the load.

[0034] In this application, the highway-railway combined beam 1 in the asymmetrical cross-section box girder of the same floor is used for highway traffic, and the railway steel box girder 2 is used for railway traffic. The highway side is a steel-concrete combined beam, that is, a concrete bridge deck 11 is set at the top of the steel beam 10, and the railway side is a steel box girder. This arrangement makes the weight per meter of the highway side in the first dead cross direction greater than that of the railway side. Because the second dead cross direction of the highway is smaller than that of the railway, by appropriately adjusting the thickness of the highway and railway second dead cross directions and the bridge deck of the combined beam, it is possible to make the sum of the first and second dead cross directions of the highway-side combined beam equal to the sum of the first and second dead cross directions of the railway-side steel box girder per meter of the transverse cross direction. This ensures that the center of gravity of the main beam section is located on the transverse centerline under dead load, eliminating the eccentric load effect caused by the asymmetrical arrangement of the highway and railway. At the same time, the concrete bridge deck 11 of the highway-side steel-concrete combined beam not only increases the weight of the main beam on the highway side, but also fully utilizes the concrete bridge deck 11 by integrating it with the steel beam 10 to share the load. Compared with the pure steel beam 10, the compressive strength of the 10 beam and the tensile strength of the 10 beam improve the stiffness and stability of the main beam, reduce the amount of steel used, and have good economic benefits. Since the highway combined beam 1 and the railway steel box girder 2 are located on both sides of the main beam, compared with the main beams arranged symmetrically on the same floor as the highway and railway, the intersection of highway and railway connection lines is avoided, the connection space requirements are reduced, and the adaptability is strong. Compared with the main beams arranged in layers for highway and railway, the bridge deck elevation of the highway combined beam 1 and the railway steel box girder 2 is lower, which has the advantages of shorter approach bridge length, smaller slope, smaller land area, and lower total project investment.

[0035] The steel beam 10 includes an upper flange and a first base plate. The upper flange is located on top of the first base plate and extends longitudinally along the bridge direction. A first web 103 and a second web 104 are disposed between the first base plate and the upper flange. That is, the first web 103 and the second web 104 are located on both sides of the space formed between the upper flange and the first base plate.

[0036] The first base plate includes a first inclined base plate 105 and a first flat base plate 106. One end of the first inclined base plate 105 is connected to the first flat base plate 106 by welding. The first inclined base plate 105 is inclined, and the connection between the first inclined base plate 105 and the first flat base plate 106 forms an obtuse angle. The other end of the first inclined base plate 105 is inclined towards the upper flange and is connected to the first web plate 103 by welding. Simultaneously, the other end of the first flat base plate 106 is connected to the second web plate 104 by welding. Therefore, the upper flange, the first web plate 103, the first inclined base plate 105, the first flat base plate 106, and the second web plate 104 are sequentially welded to form the steel beam 10.

[0037] The upper flange includes a first upper flange 100, a second upper flange 101, and a third upper flange 102. The first upper flange 100 and the second upper flange 101 are arranged along the longitudinal direction of the bridge, and the third upper flange 102 is arranged along the transverse direction of the bridge. The first upper flange 100 is located at the top of the first web 103, the second upper flange 101 is located at the top of the second web 104, and the third upper flange 102 connects the first upper flange 100 and the second upper flange 101. One end of the first upper flange 100 is welded and fixed to the top of the first web 103, one end of the third upper flange 102 is welded and fixed to the first upper flange 100, and the other end is welded and fixed to the second upper flange 101. The second upper flange 101 is welded and fixed to the second web 104.

[0038] To improve the stability of the steel beam 10 structure, multiple first transverse diaphragms 107 are arranged at intervals along the longitudinal direction of the bridge between the first web 103 and the second web 104. The first transverse diaphragms 107 are connected to the first web 103, the second web 104, the third upper flange 102, the first inclined bottom plate 105, and the first flat bottom plate 106 by welding. The third upper flange 102 is located on top of the first transverse diaphragms 107, and is situated between the first upper flange 100 and the second upper flange 101.

[0039] Based on the above embodiments, in this embodiment, the railway steel box girder 2 includes: a top plate 20, a second bottom plate, and a second transverse diaphragm 24. A third web plate 21 is provided between the second bottom plate and the top plate 20. The top plate 20 and the top of the third web plate 21 are connected by welding, and the bottom of the third web plate 21 is connected to the second bottom plate by welding.

[0040] The second base plate includes a second inclined base plate 22 and a second flat base plate 23 connected to the second inclined base plate 22. One end of the second inclined base plate 22 is welded to the second flat base plate 23, and the other end is inclined towards the top plate 20 and welded to the third web plate 21. The included angle between the second inclined base plate 22 and the second flat base plate 23 is an obtuse angle. The end of the second flat base plate 23 away from the second inclined base plate 22 can be welded to the first flat base plate 106 and the second web plate 104, or it can share a single piece of steel plate with the first flat base plate 106.

[0041] Furthermore, to improve the stability of the railway steel box girder 2, the second transverse diaphragm 24 is arranged longitudinally between the top plate 20 and the second bottom plate. The bottom end of the second transverse diaphragm 24 is connected to the second inclined bottom plate 22 and the second flat bottom plate 23 by welding, the top end of the second transverse diaphragm 24 is connected to the top plate 20 by welding, and the two sides of the second transverse diaphragm 24 are connected to the second web plate 104 and the third web plate 21 by welding, respectively.

[0042] Based on the above embodiments, in this embodiment, the steel beam 10 and the concrete bridge deck 11 are connected by a first shear connector 12.

[0043] In this embodiment, first shear connectors 12 are provided at the top of the first upper flange 100, the second upper flange 101, and the third upper flange 102; and the first upper flange 100, the second upper flange 101, and the third upper flange 102 are connected to the concrete bridge deck 11 through the first shear connectors 12. The concrete bridge deck 11 of the highway composite beam 1 not only increases the weight of the main beam on the highway side, but also, through the first shear connectors 12, is integrated with the steel beam 10 to share the load, fully utilizing the compressive strength of the concrete bridge deck 11 and the tensile strength of the steel beam 10. Compared with the pure steel beam 10, this improves the stiffness and stability of the main beam on the highway side, reduces the amount of steel used, and has good economic benefits.

[0044] Based on the above embodiments, in this embodiment, a force transmission component 3 is provided between the highway composite beam 1 and the railway steel box girder 2.

[0045] Specifically, the force transmission component 3 includes: a first stiffening rib 30, a second stiffening rib 32, a second shear connector 33, and a bearing plate 31. The first stiffening rib 30 is connected to the highway composite beam 1. The second shear connector 33 is welded onto the first stiffening rib 30, and the first stiffening rib 30 and the concrete bridge deck 11 are connected by the second shear connector 33. The second stiffening rib 32 is connected to the railway steel box girder 2. The bearing plate 31 is connected between the first stiffening rib 30 and the second stiffening rib 32. One end of the bearing plate 31 is connected to the highway composite beam 1, and the other end is connected to the railway steel box girder 2.

[0046] In this embodiment, the top end of the pressure plate 31 is fixed to one side of the top plate 20 by welding, and the bottom end is fixed to one side of the second upper flange 101 by welding. One end of the pressure plate 31 is connected to the highway composite beam 1 by welding via the first stiffening rib 30, and the other end is connected to the railway steel box girder 2 by welding via the second stiffening rib 32. Specifically, the horizontal plane of the top end of the upper flange in the highway composite beam 1 is located below the horizontal plane of the top plate 20 of the railway steel box girder 2. One side of the first stiffening rib 30 is fixed to the second upper flange 101 by welding, and the other side is fixed to the pressure plate 31 by welding. One side of the second stiffening rib 32 is fixed to the top plate 20 by welding, and the other side is fixed to the pressure plate 31 by welding.

[0047] By setting the first stiffening rib 30, the second stiffening rib 32, the second shear connector 33, and the bearing plate 31, the function is to ensure an effective and smooth transition of the transverse inward force between the top plate 20 of the railway steel box girder 2 and the concrete bridge deck 11, so that the railway steel box girder 2 and the highway composite beam 1 can form a whole in the transverse direction and share the load. The function of the second stiffening rib 32 is to evenly transfer the transverse inward force of the top plate 20 of the railway steel box girder 2 to the bearing plate 31, and then further transfer the internal force to the concrete bridge deck 11 through the bearing plate 31 and the first stiffening rib 30.

[0048] Based on the above embodiments, in this embodiment, air nozzles 4 are provided on both sides of the asymmetrical cross-section box girder of the road-rail combined beam. Specifically, air nozzles 4 are provided on both the side of the road combined beam 1 away from the railway steel box girder 2 and the side of the railway steel box girder 2 away from the road combined beam 1. By providing air nozzles 4, the aerodynamic performance of the cross-section of the asymmetrical cross-section box girder of the road-rail combined beam is improved, and the wind resistance stability of the cross-section of the asymmetrical cross-section box girder of the road-rail combined beam is enhanced.

[0049] In summary, the asymmetrical cross-section box girder with railway and highway on the same floor provided in this application prevents the main girder from generating eccentric loads under dead loads, thereby achieving a lateral self-balancing effect. The structure has reasonable stress distribution and good economic efficiency, which can solve the problem in related technologies where the dead load on the railway side of the main girder is greater than that on the highway side, resulting in a lateral eccentric load effect.

[0050] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0051] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0052] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A box girder with an asymmetrical cross-section for both road and rail transport on the same floor, characterized in that, It includes: Highway composite beam (1), the highway composite beam (1) includes a steel beam (10) and a concrete bridge deck (11) set at the top of the steel beam (10), the steel beam (10) and the concrete bridge deck (11) are both arranged along the longitudinal direction of the bridge; Railway steel box girder (2), the railway steel box girder (2) is arranged along the longitudinal direction of the bridge and is set on one side of the highway connecting beam (1); A force transmission component (3) is provided between the highway combined beam (1) and the railway steel box girder (2). The force transmission component (3) includes: a first stiffening rib (30), a second stiffening rib (32), and a bearing plate (31). The first stiffening rib (30) is connected to the highway combined beam (1), and the first stiffening rib (30) and the concrete bridge deck (11) are connected by a second shear connector (33). The second stiffening rib (32) is connected to the railway steel box girder (2). The bearing plate (31) is connected between the first stiffening rib (30) and the second stiffening rib (32). One end of the bearing plate (31) is connected to the highway combined beam (1), and the other end is connected to the railway steel box girder (2).

2. The asymmetrical cross-section box girder with railway and highway on the same floor as described in claim 1, characterized in that, The steel beam (10) includes: Upper wing edge; A first base plate, wherein a first web plate (103) and a second web plate (104) are provided between the first base plate and the upper flange.

3. The asymmetrical cross-section box girder with railway and highway on the same floor as described in claim 2, characterized in that: The first base plate includes a first inclined base plate (105) and a first flat base plate (106); One end of the first inclined bottom plate (105) is connected to the first flat bottom plate (106), and the other end is connected to the first web plate (103). The other end of the first flat bottom plate (106) is connected to the second web plate (104).

4. The asymmetrical cross-section box girder with railway and highway on the same floor as described in claim 2, characterized in that: The upper flange includes a first upper flange (100) and a second upper flange (101), the first upper flange (100) being disposed at the top of the first web (103), and the second upper flange (101) being disposed at the top of the second web (104).

5. The asymmetrical cross-section box girder with railway and highway on the same floor as described in claim 4, characterized in that: Multiple first transverse diaphragms (107) are arranged at intervals along the longitudinal direction of the bridge between the first web (103) and the second web (104).

6. The asymmetrical cross-section box girder with road and rail on the same floor as described in claim 5, characterized in that: The upper flange also includes a third upper flange (102), which is disposed on the top of the first diaphragm (107) and is located between the first upper flange (100) and the second upper flange (101).

7. The asymmetrical cross-section box girder with railway and highway on the same floor as described in claim 1, characterized in that: The steel beam (10) and the concrete bridge deck (11) are connected by a first shear connector (12).

8. The asymmetrical cross-section box girder with railway and highway on the same floor as described in claim 1, characterized in that, The railway steel box girder (2) includes: Top plate (20); A second base plate, a third web plate (21) is provided between the second base plate and the top plate (20), the second base plate includes a second inclined base plate (22) and a second flat base plate (23) connected to the second inclined base plate (22); The second diaphragm (24) is arranged longitudinally between the top plate (20) and the second bottom plate.

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