CN217974005U

CN217974005U - Combined box girder structure

Info

Publication number: CN217974005U
Application number: CN202221316605.8U
Authority: CN
Inventors: 林上顺; 暨邦冲; 林建凡; 林玉莲; 赵锦冰; 林昕
Original assignee: Fujian Communications Research Institute Co ltd; Fuzhou Peiyan Engineering Technology Co ltd; Haoyao Times Fujian Group Co ltd; Fujian University of Technology
Current assignee: Fujian Communications Research Institute Co ltd; Fuzhou Peiyan Engineering Technology Co ltd; Haoyao Times Fujian Group Co ltd; Fujian University of Technology
Priority date: 2022-05-30
Filing date: 2022-05-30
Publication date: 2022-12-06
Anticipated expiration: 2032-05-30

Abstract

The utility model relates to a bridge engineering technical field, concretely relates to combination box girder structure, comprising a base plate, the both sides of bottom plate all are provided with prefabricated web, and the top that is located two prefabricated webs is provided with the roof, be provided with the reinforcing bar in the prefabricated web, prefabricated web is worn out respectively to the upper and lower extreme of reinforcing bar and is connected with bottom plate, roof, and the length direction interval that is located along the combination box girder between two prefabricated webs is provided with a plurality of cast-in-place cross slabs, and the both ends fulcrum department that is located the combination box girder is provided with prefabricated cross slabs. The combined box girder has light hoisting weight, convenient construction, strong crack resistance of the web plate and low maintenance cost.

Description

Combined box girder structure

Technical Field

The utility model relates to a bridge engineering technical field, concretely relates to combination box girder construction.

Background

The steel box girder has the advantages of light dead weight, quick construction and the like, is a common main girder form for bridges in China, but is easy to suffer from diseases such as coating deterioration, steel corrosion, fatigue damage, easy damage of bridge deck pavement layers and the like, and the cost for regular coating and maintenance after construction is also high. The application of the concrete beam in the bridge is limited due to the reasons of large self weight, high section height, easy cracking of a web plate, difficult hoisting and the like. Compared with a steel box girder, the corrugated steel web-concrete composite girder has the problems that although the self weight of the corrugated steel web-concrete composite girder is relatively light, web steel is easy to corrode, and regular maintenance is required.

Therefore, a novel combined box girder structure is proposed, wherein a web plate of the novel combined box girder structure adopts section steel wrapped by ultra-high performance concrete (UHPC for short), and a top plate and a bottom plate of the novel combined box girder structure still adopt a prestressed common concrete structure. The web plate of the novel combined box girder structure is made of high-strength section steel and UHPC, the cross section size of the novel combined box girder structure is much smaller than that of the web plate of the traditional prestressed concrete box girder, the structural dead weight of the box girder can be obviously reduced, and the novel combined box girder structure has higher rigidity and bearing capacity; the structural steel is embedded in the UHPC, so that the corrosion phenomenon of a web plate can be avoided, the rigidity and the fatigue resistance of the structure are improved, and the maintenance cost is reduced.

In the construction method, the web plate of the novel combined box girder and the reinforcing steel bar of the bottom plate are prefabricated in a factory, the novel combined box girder and the reinforcing steel bar of the bottom plate are integrally transported to the site, then the novel combined box girder is hoisted by an automobile, and then the bearing platform of the bridge abutment is utilized to set up the portal type support, so that the cast-in-situ construction of the concrete of the top plate and the bottom plate is carried out. Compared with the traditional prestressed concrete box girder, the novel combined box girder has light hoisting weight of the prefabricated part and can be conveniently hoisted by an automobile; the cast-in-place concrete only comprises a top plate and a bottom plate, a relatively simple portal type support can be adopted, and the support uses a bearing platform as a foundation, so that the construction cost of the support can be greatly reduced compared with the traditional full-hall type support; the reinforcing steel bars of the bottom plate and the web plate are prefabricated together in a factory, so that the workload of binding the reinforcing steel bars on site can be greatly reduced, and the purpose of rapid construction can be achieved. Compared with the traditional steel box girder, the novel combined box girder only adopts the section steel at the web plate position, can greatly reduce the workload of on-site welding, anticorrosive coating and the like of steel, and is favorable for energy conservation and environmental protection.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a combination box girder construction, this combination box girder hoist and mount light in weight, construction convenience, web crack resistance can the reinforce, the maintenance cost is low.

The technical scheme of the utility model lies in: the utility model provides a combination box girder structure, includes the bottom plate, the both sides of bottom plate all are provided with prefabricated web, and the top that is located two prefabricated webs is provided with the roof, be provided with the reinforcing bar in the prefabricated web, the upper and lower extreme of reinforcing bar wears out prefabricated web respectively and is connected with bottom plate, roof, is located and is provided with a plurality of cast-in-place cross slabs along the length direction interval of combination box girder between two prefabricated webs, and is located the both ends fulcrum department of combination box girder and is provided with prefabricated cross slab.

Furthermore, the prefabricated web plate, the steel ribs, the prefabricated diaphragm plate, the stirrups of the bottom plate and the longitudinal steel bars of the bottom plate form a prefabricated hoisting structure.

Furthermore, pier top cast-in-place sections are arranged at two ends of the combined box girder along the bridge direction, and the combined box girders of two adjacent spans in one connection are connected through the pier top cast-in-place sections.

Furthermore, pier top cast-in-place section steel bars are arranged in the pier top cast-in-place section, and part of the pier top cast-in-place section steel bars are connected with part of longitudinal steel bars of the top plate, longitudinal steel bars of the prefabricated web plate and longitudinal steel bars of the bottom plate.

Furthermore, diaphragm plate reinforcing steel bars are arranged in the prefabricated diaphragm plate and the cast-in-place diaphragm plate, and part of diaphragm plate reinforcing steel bars extend into the prefabricated web plate, the top plate and the bottom plate;

furthermore, a web stirrup, a web longitudinal steel bar, an armpit steel bar and a section steel web reinforcing steel bar are arranged in the prefabricated web.

Furthermore, the top plate is of a cast-in-place structure and comprises a top plate stirrup and a top plate longitudinal steel bar; and only when the bridge forming system of the bridge is a continuous system, the middle part of the top plate is provided with top plate prestressed steel bundles in the longitudinal bridge direction at intervals along the transverse bridge direction, and the bottom surface of the top plate is provided with top plate tooth blocks.

Furthermore, the bottom plate is of a cast-in-place structure and comprises a stirrup of the bottom plate and a longitudinal steel bar of the bottom plate, a row of longitudinal bridge-direction bottom plate prestressed steel bundles are arranged in the bottom plate along a transverse bridge direction, and a bottom plate tooth block is arranged on the upper side of the bottom plate; the stirrups of part bottom plate stretch into prefabricated web.

Furthermore, the reinforcing steel comprises a reinforcing steel web arranged in the prefabricated web, the upper end of the reinforcing steel web stretches into the top plate and is provided with a reinforcing steel upper flange, upper flange studs are welded to the upper flange along the length direction at intervals, web studs are welded to the upper portion and the lower portion of the two side faces of the reinforcing steel web along the length direction at intervals, and the lower end of the reinforcing steel web stretches into the bottom plate and is provided with a lower flange.

Furthermore, a midspan web hole and a beam end web hole are formed in the steel rib web, and the radius of the beam end web hole is smaller than that of the midspan web hole; be equipped with the stiffening rib between web hole and beam-ends web hole in each strides, be equipped with the stiffening rib hole on the stiffening rib, the longitudinal reinforcement of prefabricated web passes the stiffening rib hole and adopts the PBL key-type connection as whole.

Compared with the prior art, the utility model has the advantages of it is following:

1. the combined box girder has the advantages that the structure is decomposed into the prefabricated hoisting part and the cast-in-place part by manufacturing the prefabricated web and binding part of reinforcing steel bars in advance, the advantages of the prefabricated construction method and the cast-in-place construction method are combined, the construction difficulty of the prefabricated construction method and the cast-in-place construction method is reduced, and the construction efficiency of the site is greatly improved; because the weight of the web plate is greatly reduced, the hoisting weight is light, small hoisting equipment can be adopted for hoisting, the hoisting cost is saved, and the application range is wide.

2. When the combined box girder is constructed, a portal bracket can be erected on a bearing platform of a lower structure, and both a dry bridge and a river bridge can be constructed by adopting the structure; by adopting the structure, the structure size can be reduced, the self weight and the internal force of the structure are reduced, the spanning capability and the bending resistance of the bridge are improved, and the cracking probability of the combined box girder and the structural deformation under the load action are obviously reduced; compared with a steel structure, the bridge deck has higher corrosion resistance, fire resistance and erosion resistance, the safety and durability of the structure can be improved, and the bridge deck is not easy to damage; both steel and UHPC are high-performance materials, and an SUHPC structure formed by combining the steel and the UHPC also has higher bearing capacity.

Drawings

Fig. 1 is a schematic view of a prefabricated hoisting structure of the combined box girder of the utility model;

fig. 2 is a schematic view of the vertical structure of the composite box girder of the present invention;

fig. 3 is a schematic view of the vertical arrangement of the prestressed steel bundles of the composite box girder of the present invention;

FIG. 4 is a cross-sectional view taken along line I-I of FIG. 2;

FIG. 5 is a sectional view taken along line II-II of FIG. 2;

FIG. 6 is a cross-sectional reinforcement view taken along line I-I of FIG. 2;

FIG. 7 is a cross-sectional reinforcement view of section II-II of FIG. 2;

FIG. 8 is a schematic structural view of a prefabricated diaphragm or a cast-in-place diaphragm of the present invention;

fig. 9 is a schematic view of the cross-section reinforcement of the pier top cast-in-place section of the present invention;

FIG. 10 is a schematic view of the steel skeleton vertical structure of the present invention;

FIG. 11 is a cross-sectional view of the steel frame of the present invention;

fig. 12 is a schematic view of the structure of the reinforcing steel bar with steel web holes of the present invention;

in the figure: 1. a top plate; 11. a roof stirrup; 12. longitudinal steel bars of the top plate; 13. a top plate prestressed steel strand; 14. a top plate tooth block;

2. steel skeleton; 21. a steel rib web; 211. a mid-span web hole; 212. a beam-end web hole; 22. a steel rib lower flange; 23. a steel rib upper flange; 24. an upper flange stud; 25. a web stud; 26. a stiffening rib; 261. a stiffener cavity;

3. prefabricating a web plate; 311. web stirrups; 312. web longitudinal steel bars; 313. peduncle reinforcing steel bars;

4. a base plate; 41. a stirrup for the base plate; 42. longitudinal steel bars of the bottom plate; 43. a base plate prestressed steel strand; 44. a bottom plate tooth block;

5. prefabricating a diaphragm plate; 5', casting a diaphragm plate in situ; 51. diaphragm plate reinforcing steel bars;

6. reinforcing steel bars by using the section steel web plates; 61. a reinforcing mesh; 62. longitudinal short steel bars;

7. a pier top cast-in-place section; 71. pouring section steel bars in situ on the pier top;

8. and (5) thickening the layer.

Detailed Description

In order to make the aforementioned features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below, but the present invention is not limited thereto.

Refer to fig. 1 to 12

The utility model provides a combination box girder structure, includes bottom plate 4, the both sides of bottom plate 4 all are provided with prefabricated web 3, and the top that is located two prefabricated webs 3 is provided with roof 1, be provided with reinforcing bar 2 in the prefabricated web 3, prefabricated web 3 is worn out respectively to the upper and lower extreme of reinforcing bar 2 is connected with bottom plate 4, roof 1, is located and is provided with a plurality of cast-in-place cross slab 5' along the length direction interval of combination box girder between two prefabricated webs 3, and the both ends fulcrum department that is located the combination box girder is provided with prefabricated cross slab 5.

In this embodiment, prefabricated web 3, reinforcing bar 2, prefabricated diaphragm 5 and the stirrup 41 of bottom plate, the longitudinal reinforcement 42 of bottom plate constitute prefabricated hoisting structure, and all other structures are the cast in situ structure.

The prefabricated hoisting structure is formed by the prefabricated web plate 3, the steel ribs 2, the stirrups 41 of the base plate, the longitudinal steel bars 42 of the base plate and the prefabricated diaphragm plates 5, so that the structural part can be prefabricated in a factory, the construction speed is increased, and the prefabricated hoisting structure can be used as a stress structure during construction. Through set up reinforcing bar 2 in prefabricated web 3, greatly alleviateed the weight of web, make things convenient for the small-size equipment to hoist.

In this embodiment, pier top cast-in-place sections 7 are arranged at two ends of the combined box girder along the bridge direction, and the combined box girders of two adjacent spans in one connection are connected through the pier top cast-in-place sections. And pier top cast-in-place section steel bars 71 are arranged in the pier top cast-in-place section, wherein part of the pier top cast-in-place section steel bars 71 are connected with part of longitudinal steel bars 12 of the top plate, the longitudinal steel bars 312 of the prefabricated web plate and the longitudinal steel bars 42 of the bottom plate.

In the embodiment, the thickness of the pier top cast-in-place section 7 is 1m-2m, and the pier top cast-in-place section is made of common concrete.

In this embodiment, all be equipped with diaphragm plate reinforcing bar 61 in prefabricated diaphragm plate and the cast-in-place diaphragm plate, in some diaphragm plate reinforcing bar 61 stretched into prefabricated web 3, roof 1 and bottom plate 4.

In the embodiment, the thicknesses of the prefabricated diaphragm plates 5 and the cast-in-situ diaphragm plates 5 'are both 0.2m-0.5m, the prefabricated diaphragm plates 5 are required to be arranged at the support points at the two ends of the combined box girder, and the rest cast-in-situ diaphragm plates 5' are uniformly arranged at intervals of 10m-30m along the length direction of the combined box girder. The top plate 1 and the bottom plate 4 are provided with a thickening layer 8 near the pivot, the thickness of the thickening layer 8 is 0.1m-0.3m, and the prefabricated diaphragm plates 5, the cast-in-situ diaphragm plates 5' and the thickening layer 8 are made of common concrete.

The prefabricated transverse partition plates 5 are arranged at the supporting points at the two ends, so that the prefabricated transverse partition plates can be used as temporary supports after the prefabricated hoisting structure is hoisted, and can also be used as construction templates of a cast-in-place section 7 at the top of a pouring pier; by arranging a plurality of cast-in-situ diaphragm plates 5', the integrity of the combined box girder can be improved.

In this embodiment, the top plate 1 is a cast-in-place structure, and includes a top plate stirrup 11 and a top plate longitudinal reinforcement 12; and only when the bridge forming system of the bridge is a continuous system, the middle part of the top plate is provided with top plate prestressed steel bundles 13 in the longitudinal bridge direction at intervals along the transverse bridge direction, the bottom surface of the top plate is provided with top plate toothed blocks 14, and the top plate prestressed steel bundles 13 are anchored on the top plate toothed blocks 14.

In this embodiment, the thickness of the top plate 1 is 0.15m to 0.4m, and the material of the top plate 1 is common concrete.

In this embodiment, prefabricated web 3 is prefabricated construction, is equipped with web stirrup 311, the longitudinal reinforcement of web 312, stalk axilla reinforcing bar 313 and shaped steel web reinforcing bar 6 in the prefabricated web 3, the stalk axilla reinforcing bar sets up in the corner that prefabricated web is connected with the roof. Prevent the web fracture, prevent that the concrete from dropping, reducing stress concentration through shaped steel web reinforcing bar.

In this embodiment, the thickness of the single prefabricated web is 0.15m-0.4m, and the prefabricated web 3 is made of ultra-high performance concrete.

In this embodiment, the bottom plate 4 is a cast-in-place structure, and includes a stirrup 41 of the bottom plate which is bound in advance in a factory and a longitudinal reinforcement 42 of the bottom plate which is bound in advance in the factory, a row of longitudinal bridge direction bottom plate prestressed steel bundles 43 are arranged in the bottom plate along the transverse bridge direction, and a bottom plate tooth block 44 is arranged on the upper side of the bottom plate; the stirrups 41 of the partial bottom plates extend into the prefabricated web 3 and are connected to the prefabricated web.

In this embodiment, the thickness of the bottom plate 4 is 0.15m to 0.4m, and the material of the bottom plate 4 is common concrete.

In the embodiment, the thickness of the steel rib 2 is 0.01m-0.05m, and the material is common carbon structural steel. The steel skeleton 2 comprises a steel skeleton web 21 arranged in a prefabricated web 3, the upper end of the steel skeleton web 21 extends into the top plate 1 and is provided with a steel skeleton upper flange 23, the edge of the steel skeleton upper flange 23 is welded with upper flange studs 24 at intervals along the length direction, web studs 25 are welded at equal intervals along the length direction at the upper part and the lower part of the two side faces of the steel skeleton web 21, and the lower end of the steel skeleton web extends into the bottom plate 4 and is provided with a steel skeleton lower flange 22. The longitudinal arrangement distance between the upper flange bolt 24 and the web bolt 25 is 0.05-0.5 m, and the material is ML15 or ML15A1 steel.

In this embodiment, the steel rib web 21 is provided with a circular mid-span web hole 211 and a beam-end web hole 212, the radius of the beam-end web hole 212 is smaller than that of the mid-span web hole 211, and the radius of the beam-end web hole 211 is 0.1m-0.8m; the radius of the midspan web hole 212 is 0.3m-1.2m. Be equipped with stiffening rib 26 between each midspan web hole 211 and beam-ends web hole 212, be equipped with stiffening rib hole 261 on the stiffening rib 26, the longitudinal reinforcement 312 of prefabricated web passes stiffening rib hole 261 and adopts the PBL key-type connection as an organic whole. The steel web reinforcing steel bar comprises a steel mesh 61 and transverse short steel bars 62. In order to improve the crack resistance of the web, the steel web reinforcing steel bars are arranged in the web along the full cross section of the bridge direction, and the transverse short steel bars 62 are only required to be arranged when the steel web reinforcing steel bars are arranged in the span web holes 211 or the beam end web holes 212.

The steel rib lower flange 21 and the steel rib upper flange 22 are arranged on the steel rib 2, so that the steel rib 2 can be better placed and fixed in the steel reinforcement framework to form a whole, slippage between steel and concrete materials is prevented, and the steel is more fully loaded.

The steel rib upper flange 22 is provided with an upper flange stud 24 extending into the top plate 1 and serving as a shear connector to connect the steel rib 2 with the top plate 1, so that the shear resistance of the structure is improved, and the slippage between the top plate 1 and the steel rib 2 is further prevented.

By arranging the midspan web hole 211 and the beam end web hole 212 on the steel rib web 21, materials are saved, the self weight of the structure is reduced, and the manufacturing cost is reduced.

By passing the longitudinal web rebars 312 through the stiffener holes 261 in the stiffeners 26, not only is the integrity of the section steel and rebars enhanced, but the stress concentration across the web holes 211 and beam end web holes 212 is also reduced.

Through setting up shaped steel web reinforcing bar 6, not only strengthened the bearing capacity who strides well web hole 211 and beam-ends web hole 212, can also prevent that the concrete material of hole department from dropping and strengthening the anti ability of splitting of prefabricated web 3 when the structure destroys.

The construction method of the combined box girder comprises the following steps:

the method comprises the following steps: determining the span of the bridge and a bridge system, and determining the specific size of each part according to the span.

Step two: and (2) binding the stirrups 41 of the bottom plate and the longitudinal steel bars 42 of the bottom plate in a prefabricated yard, then installing the steel ribs 2 which are prefabricated in advance but not welded with the upper flange studs 24, binding the web stirrups 311, the web longitudinal steel bars 312, the peduncle steel bars 313 and the profile steel web reinforcing steel bars 6 of the prefabricated web 3 to form an integral steel rib 2 and a steel reinforcement framework, and binding the steel bars 61 of the prefabricated diaphragm plate and the cast-in-situ diaphragm plate.

Step three: pouring two prefabricated webs 3 and prefabricated diaphragm plates 5 arranged at the branch points respectively to form a prefabricated hoisting structure, and maintaining the prefabricated hoisting structure in a prefabricated field according to relevant specifications; and (4) after the strength of the material reaches a specified value required in the specification, tensioning the web prestressed steel bundles, and transporting to a construction site.

Step four: a portal support is arranged on a bearing platform of a lower structure on site, then the prefabricated hoisting structure is hoisted to a designed main beam position through hoisting equipment, at the moment, a prefabricated diaphragm plate 5 arranged at a fulcrum is used as a temporary support of the prefabricated hoisting structure, a bottom plate 4 of the combined box girder is poured, and after the material strength reaches a specified value required in a specification, a bottom plate prestressed steel beam 43 is tensioned and anchored on a bottom plate tooth block 44; pouring the residual cast-in-place diaphragm plate 5'; welding an upper flange stud 24 on the steel rib upper flange 23, binding the top plate stirrup 11 and the top plate longitudinal steel bar 12, and pouring the top plate 1; binding a reinforcing steel bar 71 of the pier top cast-in-place section, pouring a pier top cast-in-place section 7 by taking the prefabricated diaphragm plate 5 arranged at the fulcrum as a template, and connecting the adjacent two-span combined box girders in one block; when the bridge forming system of the bridge is a continuous system, the prestressed steel bundles of the tensioning top plate are required to be arranged and anchored on the tooth blocks of the top plate.

The first embodiment is as follows:

bridges often need to be built across rivers, and cofferdams are generally arranged in rivers in the traditional construction method to build full-space supports. The structure provided by the invention is used for river-crossing bridges. The invention has the advantages that the structure is divided into the prefabricated hoisting part and the cast-in-place part, and the advantages of the prefabricated construction method and the cast-in-place construction method are combined, so that a relatively simple portal support can be built on a bearing platform of a lower structure during construction, the construction difficulty of the prefabricated construction method and the cast-in-place construction method is reduced, the cost of cofferdams and supports and the cofferdam building time are saved, and the construction progress is accelerated.

The second embodiment:

when the dry bridge is built in the middle, because large-scale hoisting equipment is inconvenient to adopt, the lightening of the structure is particularly important in the construction of the bridge, and the structure provided by the invention is used for the dry bridge. The structure is divided into a prefabricated hoisting part and a cast-in-place part, and the web plate adopts the UHPC and the section steel with high strength, so that the weight of the hoisting structure is greatly reduced, and the hoisting cost is saved by adopting an automobile for hoisting during construction; the reinforcing bars of the top plate and the bottom plate and the web plate are prefabricated together in a factory, the workload of binding the reinforcing bars on site can be greatly reduced, the construction speed is high, the construction period is short, and the influence of construction on traffic is greatly reduced.

The above is only the preferred embodiment of the present invention, and all the equivalent changes and modifications made according to the claims of the present invention should be covered by the present invention.

Claims

1. The utility model provides a combination box girder structure, includes the bottom plate, its characterized in that, the both sides of bottom plate all are provided with prefabricated web, and the top that is located two prefabricated webs is provided with the roof, be provided with the reinforcing bar in the prefabricated web, the upper and lower extreme of reinforcing bar wears out prefabricated web respectively and is connected with bottom plate, roof, is located and is provided with a plurality of cast-in-place cross slabs along the length direction interval of combination box girder between two prefabricated webs, and the both ends fulcrum department that is located combination box girder is provided with prefabricated cross slab.

2. The assembled box girder structure of claim 1, wherein the prefabricated web plate, the steel ribs, the prefabricated diaphragm plate, the stirrups of the bottom plate and the longitudinal steel bars of the bottom plate form a prefabricated hoisting structure.

3. A combined box girder structure according to claim 1 or 2, wherein pier top cast-in-place sections are provided at both ends of the combined box girder in the bridge direction, and the combined box girders of two adjacent spans in a unit are connected through the pier top cast-in-place sections.

4. The composite box girder structure of claim 3, wherein the pier top cast-in-place section is provided with pier top cast-in-place section steel bars, wherein part of the pier top cast-in-place section steel bars are connected with part of longitudinal steel bars of the top plate, longitudinal steel bars of the prefabricated web plate and longitudinal steel bars of the bottom plate.

5. A composite box girder structure according to claim 1, 2 or 4 wherein the prefabricated diaphragm plates and the cast-in-place diaphragm plates are provided with diaphragm plate reinforcing bars, and part of the diaphragm plate reinforcing bars extend into the prefabricated web plate, the top plate and the bottom plate.

6. A composite box girder structure according to claim 1, 2 or 4, wherein the prefabricated web plates are provided with web stirrups, web longitudinal reinforcements, pedunculate reinforcements and section steel web reinforcing reinforcements.

7. The composite box girder structure according to claim 1, wherein the top plate is a cast-in-place structure comprising a top plate stirrup and a top plate longitudinal reinforcement; and only when the bridge forming system of the bridge is a continuous system, the middle part of the top plate is provided with top plate prestressed steel beams in the longitudinal bridge direction at intervals along the transverse bridge direction, and the bottom surface of the top plate is provided with top plate tooth blocks.

8. The combined box girder structure of claim 1, wherein the bottom plate is a cast-in-place structure and comprises stirrups of the bottom plate and longitudinal reinforcements of the bottom plate, a row of longitudinal bridge-direction bottom plate prestressed steel bundles are arranged in the bottom plate along a transverse bridge direction, and a bottom plate tooth block is arranged on the upper side of the bottom plate; the stirrups of part bottom plate stretch into prefabricated web.

9. The combined box girder structure according to claim 1, 2, 4, 7 or 8, wherein the steel ribs comprise a steel rib web plate arranged in a prefabricated web plate, the upper end of the steel rib web plate extends into the top plate and is provided with a steel rib upper flange, upper flange studs are welded to the steel rib upper flange at intervals along the length direction, web stud bolts are welded to the upper portion and the lower portion of the two side faces of the steel rib web plate at intervals along the length direction, and the lower end of the steel rib web plate extends into the bottom plate and is provided with a steel rib lower flange.

10. The composite box girder structure of claim 9, wherein the steel skeleton web is provided with a mid-span web hole and a beam end web hole, and the radius of the beam end web hole is smaller than that of the mid-span web hole; and a stiffening rib is arranged between each midspan web plate hole and the beam end web plate hole, a stiffening rib hole is formed in the stiffening rib, and the longitudinal steel bar of the prefabricated web plate penetrates through the stiffening rib hole and is connected into a whole by adopting PBL (Poly-p-phenylene-L) keys.