A steel-concrete combined section for a long-span double-sided box-mixed girder cable-stayed bridge

Abstract

The present invention discloses a steel-concrete combined section for a large-span double-sided box hybrid girder cable-stayed bridge, comprising a steel beam transition section, a combined portion and a concrete beam transition section; the steel beam transition section is a section in which the main span steel beam extends into the steel-concrete combined section, and a plurality of variable-section reinforcing ribs are arranged on the top plate, the bottom plate and the web of the steel beam transition section, the front end of the variable-section reinforcing rib is connected to the longitudinal stiffening ribs on the top plate, the bottom plate and the web of the main span steel beam, and the rear end of the variable-section reinforcing rib is connected to the pressure plate; the combined portion is a combined section section formed by the steel cell and the concrete; the concrete beam transition section is a section in which the side span concrete beam extends into the steel-concrete combined section; the steel-concrete combined section has a simple structure and a reasonable design, and has the advantages of fast construction speed, convenient concrete pouring, high construction quality and clear force transmission.

Description

Technical Field

[0001] The invention relates to the technical field of cable-stayed bridges, and in particular to a steel-concrete combined section for a large-span double-sided box hybrid beam cable-stayed bridge. Background Art

[0002] With the continuous development of bridge construction in my country, the requirements for the span of bridges are also constantly increasing. Hybrid beam cable-stayed bridges have adopted a structural form of side span concrete and middle span steel beams, which fully utilizes the advantages of different materials, has excellent mechanical performance, good economy, and excellent span performance. Therefore, they have been used more and more widely in recent years. However, due to the large difference in cross-sectional dimensions between concrete beams and steel beams, the stiffness and bearing capacity of the connection point change greatly, which has become the weak point of the entire structural system. Therefore, the steel-concrete joint section is a key component of the design and construction of hybrid beam cable-stayed bridges. In the past, the joint section of hybrid beam cable-stayed bridges had a complex structure, and concrete pouring was very difficult, and the construction quality was often difficult to guarantee.

[0003] As a new type of bridge cross-section, the double-sided box-type main beam section has the advantages of good force-bearing performance, light weight, and beautiful appearance. In recent years, it has been widely used in newly built cable-stayed bridges in my country, but it is relatively rare in hybrid beam cable-stayed bridges. The new bridge structure system using double-sided box concrete beams on the side spans and double-sided box steel beams on the main span will have the advantages of both hybrid beams and double-sided box section beams, and has broad application prospects. For example, the Chinese utility model patent (CN208733447U) disclosed in 2019 a steel-concrete transition section structure of the main beam of a wide bridge deck hybrid beam cable-stayed bridge. In the transition section, vertical stiffening ribs and transverse stiffening ribs welded to the steel longitudinal beams are arranged at intervals to form an intermediate cell and an annular cell surrounding it. The longitudinal ends of the annular cell are closed by the rear pressure plate and the front pressure plate. Welding nails are arranged on the inner wall of each annular cell, and concrete is poured into each annular cell through the connecting hole. This structure can reduce the impact of changes in stiffness and constant load on the main beam stress, but the huge axial force transmission in the side box is unclear, and further improvement and optimization of the stress structure is needed. Summary of the invention

[0004] The purpose of the present invention is to provide a steel-concrete combined section for a large-span double-sided box hybrid beam cable-stayed bridge in view of the problems existing in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge, wherein the front end of the steel-concrete combined section is connected to the main span steel girder and the rear end is connected to the side span concrete girder, and the steel-concrete combined section comprises a steel girder transition section, a combined portion and a concrete girder transition section;

[0007] The steel beam transition section is a section of the main span steel beam extending into the steel-concrete combination section, and a plurality of variable-section reinforcing ribs are arranged on the top plate, bottom plate and web of the steel beam transition section, the front end of the variable-section reinforcing rib is connected to the longitudinal reinforcing ribs on the top plate, bottom plate and web of the main span steel beam, and the rear end of the variable-section reinforcing rib is connected to the pressure plate; the pressure plate is poured with concrete on one side of the side span concrete beam, and a plurality of welded nail shear connectors are arranged on the steel surface of the pressure plate in contact with the concrete;

[0008] The joint is a combined cross-section segment formed by the steel cell and the concrete, and a joint steel cell web and an open rib with non-closed holes are provided in the joint. The joint steel cell web and the open rib respectively pass through the steel bars in the open holes and the concrete in the steel cell to form a shear connector; the concrete beam transition section is a segment of the side span concrete beam extending into the steel-concrete joint section.

[0009] The steel-concrete joint section has a simple structure and reasonable design and has the advantages of fast construction speed, convenient concrete pouring, high construction quality and clear force transmission. It can effectively improve the shortcomings of the existing technology of large-span double-sided box hybrid beam cable-stayed bridge joint section, such as complex joint section structure, large pressure plate thickness and difficulty in passing steel bars through the holes of the perforated plate connector due to the huge force transmission of the side boxes.

[0010] In this steel-concrete joint section, the top plate, bottom plate and web of the main span steel beam are extended to the steel-concrete joint section to form a steel beam transition section, and variable-section strengthening stiffening ribs are arranged on the top plate, bottom plate and web of the steel beam transition section, holes are opened on the steel cell web and the steel bars and concrete in the cell are passed through to form shear connectors, multiple steel connectors with non-closed opening ribs are arranged inside the cell, and a pressure plate is arranged at the part where the transition section steel beam is connected to the joint, so this steel-concrete joint section can firmly connect the main span composite beam and the side span concrete beam together, and has the characteristics of high structural strength, good stability, and balanced force transmission and stress temperature. Since the force of this steel-concrete joint section is reasonable, and the section stiffness and stress transition are smooth, its connection quality is easy to be guaranteed.

[0011] Furthermore, a number of prestressed steel bars are provided in the joint, one end of the prestressed steel bar is connected to the pressure plate, and the other end extends into the transition section of the concrete beam.

[0012] The provision of the prestressed steel bars can not only play a role in overall connection reinforcement, but also offset possible tensile stress to ensure the bonding stability between steel and concrete.

[0013] Furthermore, the cross-sectional forms of the main span steel beam and the side span concrete beam are both double-sided box sections.

[0014] Furthermore, the variable-section reinforcing stiffening rib is one of a U-shaped embedded T-shaped, a U-shaped externally connected T-shaped, or a U-shaped externally connected double T-shaped stiffening rib.

[0015] Furthermore, the inner side box of the joint is composed of a plurality of the steel cells, with a space left in the middle, and the bridge deck portion of the joint is composed of a single layer of cells.

[0016] Furthermore, the webs of the steel lattices at the joint portion correspond to the variable-section reinforcing ribs respectively. The transition section of the steel beam in the middle of the steel lattices where the webs are not arranged is also provided with variable-section reinforcing ribs.

[0017] Furthermore, the side box of the concrete beam transition section is a solid section, the strength of the bridge deck portion of the concrete beam transition section is higher than the strength of the bridge deck portion of an ordinary concrete beam, and a transverse diaphragm is arranged in this section.

[0018] Furthermore, the diameter of the welded nail shear connector is 16-22 mm, the length is 150-200 mm, and the spacing between adjacent welded nail shear connectors does not exceed 300 mm. The welded nail shear connector can improve the bonding strength between the pressure plate and concrete.

[0019] Furthermore, a casting hole and an air outlet hole are reserved at the top of the joint, and a connecting hole is reserved on the web of the steel cell of the joint.

[0020] The pouring holes facilitate on-site pouring of concrete, the vent holes facilitate rapid exhaust, and the connecting holes enable concrete to pass through and enter the space separated by each abdomen.

[0021] Furthermore, when viewed from the lateral direction of the bridge, it includes the side box cantilever, the side box main beam and the bridge deck part in sequence, and the longitudinal directions of the side box cantilever, the side box main beam and the bridge deck part all include the steel beam transition section, the joint and the concrete beam transition section.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. The steel-concrete combining section has a simple structure and a reasonable design, and has the advantages of fast construction speed, convenient concrete pouring, high construction quality, and clear force transmission; 2. It can effectively improve the shortcomings of the prior art large-span double-sided box hybrid beam cable-stayed bridge combining section, which has a complex combining section structure, a large thickness of the pressure plate, and difficulty in construction of steel bars through the holes of the perforated plate connectors due to the huge force transmission of the side boxes; 3. The steel-concrete combining section can firmly connect the main span composite beam and the side span concrete beam together, and has the characteristics of high structural strength, good stability, and balanced force transmission and stress temperature. Since the force of the steel-concrete combining section is reasonable, and the section stiffness and stress transition are smooth, the connection quality is easy to be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a top view schematic diagram of a steel-concrete combined section for a large-span double-sided box hybrid beam cable-stayed bridge according to the present invention;

[0024] Figure 2 for Figure 1 AA line section view;

[0025] Figure 3 for Figure 1 BB line cross-sectional view;

[0026] Figure 4 It is a schematic diagram of the belly of the steel cell of the joint part of the present invention;

[0027] Figure 5 It is a schematic diagram of a non-closed type perforated rib plate shear connector of the present invention;

[0028] Figure 6 It is a schematic diagram of the structure of the variable cross-section strengthening stiffening rib of the present invention;

[0029] In the figure: 1. Steel beam transition section; 2. Joint; 3. Concrete beam transition section; 4. Side box cantilever; 5. Side box main beam; 6. Bridge deck; 1-1. Variable cross-section reinforcement ribs; 1-2. Top plate; 1-3. Top plate U ribs; 1-4. Top plate T ribs; 2-1. Casting holes; 2-2. Opening ribs; 2-3. Joint steel cell webs; 2-4. Bearing plates; 2-5. Welded shear connectors; 2-6. Web openings; 2-7. Connecting holes; 2-8. Non-closed holes; 3-1. Concrete beam transition section cross beam; 3-2. Prestressed steel bars; D indicates the longitudinal direction of the bridge. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "middle", "upper", "lower", "left", "right", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0032] Embodiment 1:

[0033] like Figures 1 to 5As shown, a steel-concrete combined section for a large-span double-sided box hybrid girder cable-stayed bridge, the front end of the steel-concrete combined section is connected to the main span steel girder, and the rear end is connected to the side span concrete girder, and the steel-concrete combined section includes a steel beam transition section 1, a combined portion 2 and a concrete beam transition section 3;

[0034] The steel beam transition section 1 is a section of the main span steel beam extending into the steel-concrete combination section, and a plurality of variable-section reinforcing ribs 1-1 are arranged on the top plate, bottom plate and web of the steel beam transition section 1, the front end of the variable-section reinforcing rib 1-1 is connected to the longitudinal reinforcing ribs on the top plate, bottom plate and web of the main span steel beam, and the rear end of the variable-section reinforcing rib 1-1 is connected to the pressure plate 2-4; the pressure plate 2-4 is poured with concrete on one side of the side span concrete beam, and a plurality of welded nail shear connectors 2-5 are arranged on the steel surface of the pressure plate 2-4 in contact with the concrete;

[0035] The joint 2 is a combined cross-section segment formed by the steel cell and the concrete, and a joint steel cell web 2-3 and an open rib 2-2 with a non-closed hole 2-8 are provided in the joint. The joint steel cell web 2-3 and the open rib 2-2 respectively pass through the steel bars in the open holes and the concrete in the steel cell to form a shear connector; the concrete beam transition section 3 is a segment where the side span concrete beam extends into the steel-concrete joint section, and a transversely connected concrete beam transition section crossbeam 3-1 is provided in the concrete transition section to ensure the overall strength of the concrete transition section.

[0036] The steel-concrete joint section has a simple structure and reasonable design and has the advantages of fast construction speed, convenient concrete pouring, high construction quality and clear force transmission. It can effectively improve the shortcomings of the existing technology of large-span double-sided box hybrid beam cable-stayed bridge joint section, such as complex joint section structure, large pressure plate thickness and difficulty in passing steel bars through the holes of the perforated plate connector due to the huge force transmission of the side boxes.

[0037] In this steel-concrete joint section, the top plate, bottom plate and web of the main span steel beam are extended to the steel-concrete joint section to form a steel beam transition section 1, and variable-section reinforcing ribs 1-1 are arranged on the top plate, bottom plate and web of the steel beam transition section 1, holes are opened on the web 2-3 of the steel cell at the joint and the steel bars and concrete in the cell are passed through to form shear connectors, multiple steel connectors with non-closed opening ribs are arranged inside the cell, and pressure plates 2-4 are arranged at the part where the steel beam transition section 1 is connected to the joint 2. Therefore, this steel-concrete joint section can firmly connect the main span composite beam and the side span concrete beam together, and has the characteristics of high structural strength, good stability, and balanced force transmission and stress temperature. Since the force of this steel-concrete joint section is reasonable, and the section stiffness and stress transition are smooth, its connection quality is easy to be guaranteed.

[0038] Furthermore, a number of prestressed steel bars 3 - 2 are provided in the joint 2 , one end of the prestressed steel bar 3 - 2 is connected to the pressure plate 2 - 4 , and the other end extends into the concrete beam transition section 3 .

[0039] The provision of the prestressed steel bars 3-2 can not only play a role in overall connection reinforcement, but also offset possible tensile stress to ensure the bonding stability between steel and concrete.

[0040] Furthermore, the cross-sectional forms of the main span steel beam and the side span concrete beam are both double-sided box sections.

[0041] Furthermore, the variable-section reinforcing rib 1-1 is one of a U-shaped embedded T-shaped, a U-shaped external T-shaped or a U-shaped external double T-shaped stiffening rib.

[0042] Furthermore, the inner side box of the joint 2 is composed of a plurality of the steel cells at the top, bottom, left and right, with a non-solid section having space in the middle, and the bridge deck portion of the joint 2 is composed of a single-layer cell.

[0043] Furthermore, the webs 2-3 of the steel lattice at the joint are respectively arranged corresponding to the variable cross-section reinforcing ribs 1-1. The transition section of the steel beam in the middle of the steel lattice where the webs are not arranged is also arranged with variable cross-section reinforcing ribs.

[0044] Furthermore, the side box of the concrete beam transition section 3 is a solid section, the strength of the bridge deck portion of the concrete beam transition section 3 is higher than the strength of the bridge deck portion of an ordinary concrete beam, and a transverse diaphragm is arranged in this section.

[0045] Furthermore, the diameter of the welding nail shear connector 2-5 is 20mm, the length is 150mm, and the spacing between adjacent welding nail shear connectors does not exceed 300mm. The welding nail shear connector can improve the bonding strength between the pressure plate and concrete.

[0046] Furthermore, a casting hole 2-1 and an air outlet are reserved at the top of the joint 2, and a connecting hole 2-7 is reserved in the web 2-3 of the steel cell of the joint. The non-closed hole 2-8 on the perforated rib 2-2 is a structure with an open groove below the circular hole, and the circular hole is arranged correspondingly to the web opening 2-6 on the web of the steel cell of the joint, and a steel bar is passed through the hole to connect the formed fixed structure.

[0047] The pouring holes 2-1 facilitate on-site pouring of concrete, the vent holes facilitate rapid exhaust, and the connecting holes 2-7 enable concrete to pass through into the space separated by each abdomen.

[0048] Furthermore, viewed from the lateral direction of the bridge, it includes a side box cantilever 4, a side box main beam 5 and a bridge deck portion 6 in sequence, and the longitudinal directions of the side box cantilever 4, the side box main beam 5 and the bridge deck portion 6 all include the steel beam transition section 1, the joint 2 and the concrete beam transition section 3.

[0049] Embodiment 2:

[0050] This embodiment provides a structure of a variable-section reinforced stiffening rib.

[0051] like Figure 6 As shown, the variable cross-section reinforcing rib 1-1 includes a top plate 1-2, a U-shaped top plate U rib 1-3 is provided below the top plate 1-2, a top plate T rib 1-4 is provided below the top plate U rib 1-3, a horizontal portion of the top plate T rib 1-4 is provided below, and a vertical portion of the top plate T rib 1-4 passes through the middle of the top plate U rib 1-3 and extends upward to connect with the top plate 1-2. Both side ribs of the top plate U rib 1-3 are inclined.

[0052] The variable cross-section reinforcing ribs of this structure have a higher connection support strength, and the cross-section can be gradually changed, that is, the horizontal parts of the top plate U ribs 1-3 and the top plate T ribs 1-4 are inclined and gradually set when viewed from the side.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A steel-concrete combination section for a long-span double-sided box hybrid girder cable-stayed bridge, wherein the front end of the steel-concrete combination section is connected to the main span steel beam, and the rear end is connected to the side span concrete beam, and the steel-concrete combination section includes a steel beam transition section, a combination portion and a concrete beam transition section; characterized in that: The steel beam transition section is a section of the main span steel beam extending into the steel-concrete combination section, and a plurality of variable-section reinforcing ribs are arranged on the top plate, bottom plate and web of the steel beam transition section, the front end of the variable-section reinforcing rib is connected to the longitudinal reinforcing ribs on the top plate, bottom plate and web of the main span steel beam, and the rear end of the variable-section reinforcing rib is connected to the pressure plate; the pressure plate is poured with concrete on one side of the side span concrete beam, and a plurality of welded nail shear connectors are arranged on the steel surface of the pressure plate in contact with the concrete; The joint is a combined cross-section segment formed by the steel cell and the concrete. The joint is provided with a joint steel cell web and an open rib with a non-closed hole. The non-closed hole on the open rib is a structure with an open groove below the circular hole. The circular hole is arranged corresponding to the web opening on the web of the steel cell of the joint. The joint steel cell web and the open rib pass through the steel bar in the open hole to form a shear connector with the concrete in the steel cell respectively; the concrete beam transition section is a section where the side span concrete beam extends into the steel-concrete joint section; The webs of the steel lattice at the joint respectively correspond to the variable-section reinforcing ribs, and the steel beam transition section where no web is arranged in the middle of the steel lattice is also provided with variable-section reinforcing ribs; viewed from the lateral direction of the bridge, it includes the side box cantilever, the side box main beam and the bridge deck section in sequence, and the longitudinal directions of the side box cantilever, the side box main beam and the bridge deck section all include the steel beam transition section, the joint and the concrete beam transition section; the side box of the concrete beam transition section is a solid section, the strength of the bridge deck section of the concrete beam transition section is higher than that of the ordinary concrete beam bridge deck section, and a cross partition is arranged in this section.

2. The steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge according to claim 1, characterized in that: A number of prestressed steel bars are also arranged in the joint, one end of the prestressed steel bar is connected to the pressure plate, and the other end extends into the transition section of the concrete beam.

3. The steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge according to claim 1, characterized in that: The cross-sections of the main span steel beam and the side span concrete beam are both double-sided box sections.

4. The steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge according to claim 1, characterized in that: The variable cross-section reinforcing stiffening rib is one of a U-shaped embedded T-shaped stiffening rib, a U-shaped externally connected T-shaped stiffening rib, or a U-shaped externally connected double T-shaped stiffening rib.

5. The steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge according to claim 1, characterized in that: The inner side box of the joint is composed of a plurality of the steel cells, with a space left in the middle, and the bridge deck part of the joint is composed of a single-layer cell.

6. The steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge according to claim 1, characterized in that: The diameter of the welding nail shear connector is 16-22 mm, the length is 150-200 mm, and the spacing between adjacent welding nail shear connectors does not exceed 300 mm.

7. The steel-concrete combined section for a long-span double-sided box hybrid girder cable-stayed bridge according to claim 1, characterized in that: A casting hole and an air outlet hole are reserved on the top of the joint, and a connecting hole is reserved on the web of the steel cell of the joint.

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