A large cantilever steel box girder

Abstract

A large cantilever steel box girder comprises a top plate, a bottom plate, an inner web, an outer web, a main box chamber diaphragm, an inclined bottom plate, a cantilever web, a cantilever box chamber diaphragm, a top plate longitudinal stiffening rib, a bottom plate longitudinal stiffening rib, an inner web longitudinal stiffening rib, an outer web first longitudinal stiffening rib, and an outer web second longitudinal stiffening rib; a second outer web longitudinal stiffening rib is arranged on the inner side surface of the outer web, and the second outer web longitudinal stiffening rib is arranged corresponding to the inner side edge of the inclined bottom plate; the cantilever box chamber diaphragm comprises a diaphragm web, a diaphragm flange plate, a diagonal brace, and a node plate. The main box chamber is the main longitudinal load-bearing component, and the diaphragm of the cantilever box chamber adopts a structure that combines solid-web diaphragms and hollow-web trusses, which meets the requirements of beam width and lateral force. The structural force form is clear, providing sufficient lateral stiffness and a light structure. The cantilever of the entire bridge is unified, which is convenient for factory construction. It is suitable for both equal-height steel box girder bridges and variable-height and variable-width steel box girder bridges.

Description

Technical Field

[0001] The invention belongs to the technical field of bridges, and in particular relates to a large cantilever steel box girder. Background Art

[0002] With the development of social economy, traffic volume is increasing and the width of bridges is getting larger and larger. In recent years, large-span steel box (combined steel box) continuous beams with a width of more than 60 meters have appeared.

[0003] In these large-span steel box (combined steel box) continuous beams, the beam height is generally high, and the beam height varies along the longitudinal direction of the bridge. The beam height in the middle of the span is lower than the beam height at the support point. If the horizontal direction is set to a uniform cross-section, the deadweight will be too large and the appearance will appear bulky. For such steel box girders or combined steel box girder bridges with large widths, uniform or variable heights, the horizontal design is a complex but necessary task.

[0004] Among them, the design of the diaphragm is extremely important. Existing diaphragms generally adopt solid-web diaphragms or hollow-web diaphragms. For such steel box girders or composite steel box girder bridges with large width, equal height or variable height, if the diaphragm adopts a solid-web diaphragm, in order to ensure that the diaphragm does not become unstable, it is necessary to set up sufficient vertical and transverse stiffening ribs, which will increase the deadweight of the structure and cause waste of resources; if the diaphragm adopts a hollow-web diaphragm, the diagonal brace generally adopts channel steel and circular cross-section, but the out-of-plane stiffness of the channel steel cross-section is very small, and the welding point between the circular cross-section and the node plate is prone to fatigue damage, which makes it difficult to cope with the complex stress state on the diagonal brace. Summary of the invention

[0005] In view of the above problems, the present invention provides a large cantilever steel box girder.

[0006] The purpose of the present invention can be achieved through the following technical scheme: a large cantilever steel box girder, comprising a top plate, a bottom plate, an inner web, an outer web, a main box chamber diaphragm, an inclined bottom plate, a cantilever web, a cantilever box chamber diaphragm, a top plate longitudinal stiffening rib, a bottom plate longitudinal stiffening rib, an inner web longitudinal stiffening rib, an outer web first longitudinal stiffening rib, and an outer web second longitudinal stiffening rib; the inner part of the top plate, the bottom plate, the inner web, the outer web, and the main box chamber diaphragm constitute the main box chamber, and the outer part of the top plate, the inclined bottom plate, the cantilever web, the outer web, and the cantilever box chamber diaphragm constitute the cantilever box chamber, the inner side edge of the inclined bottom plate is welded to the outer side surface of the outer web, the inner side surface of the top plate is provided with a top plate longitudinal stiffening rib, and the inner side surface of the bottom plate is provided with a The bottom plate longitudinal stiffening ribs, the inner side surfaces of the inner web and the outer web are respectively provided with inner web longitudinal stiffening ribs and outer web first longitudinal stiffening ribs, and the inner side surface of the outer web is provided with an outer web second longitudinal stiffening rib corresponding to the inner side edge of the inclined bottom plate; the boom box room diaphragm includes a diaphragm web, a diaphragm flange plate, and a diagonal brace assembly, a hole is opened on the diaphragm web, and the diaphragm flange plate is arranged along the edge of the hole, and multiple groups of diagonal brace assemblies are arranged in the holes of the diaphragm web, each group of diagonal brace assemblies includes a diagonal brace, a node plate, and high-strength bolts, the diagonal brace is an angle steel, and the two diagonal braces of each group of diagonal brace assemblies are arranged back to back, and the two ends are respectively connected to the two node plates by high-strength bolts, and the two node plates are connected to the diaphragm flange plate.

[0007] Furthermore, the main compartment transverse diaphragm also includes a transverse diaphragm web, a transverse diaphragm flange plate, and a diagonal brace assembly. Furthermore, the multiple groups of diagonal brace assemblies of the main compartment transverse diaphragm are arranged in a V-shape or an X-shape in the holes of the transverse diaphragm web.

[0008] Furthermore, the main chamber partition is a solid-belly partition.

[0009] Furthermore, it also includes longitudinal stiffening ribs of the web of the cantilever arm, and the longitudinal stiffening ribs of the web of the cantilever arm are provided on the inner side surface of the web of the cantilever arm.

[0010] Furthermore, the second longitudinal stiffening rib of the outer web is T-shaped, and the second longitudinal stiffening rib of the outer web includes a stiffening rib web and a stiffening rib flange plate, the stiffening rib web is perpendicular to the outer web, and one side edge of the stiffening rib web is connected to the inner side surface of the outer web, and the stiffening rib flange plate is parallel to the outer web and connected to the other side edge of the stiffening rib web.

[0011] Furthermore, it also includes longitudinal stiffening ribs of the inclined bottom plate, and the inner side surface of the inclined bottom plate is provided with the longitudinal stiffening ribs of the inclined bottom plate.

[0012] Furthermore, the inclined bottom plate is provided with holes.

[0013] Compared with the prior art, the present invention has the following beneficial effects: the force form is clear, the main box chamber is the main longitudinal force-bearing member, the main box chamber diaphragm can adopt either a solid-web diaphragm or a structure combining a solid-web diaphragm and a hollow-web truss, wherein the hollow-web truss can be arranged into a V-shaped or X-shaped hollow-web truss according to different beam heights; the cantilever box chamber meets the structural requirements of a wider beam width and the lateral force requirements, and the cantilever box chamber diaphragm adopts a structure combining a solid-web diaphragm and a hollow-web truss; stiffening ribs corresponding to the inner side edges of the inclined bottom plate are provided on the inner side surface of the outer web, thereby ensuring the lateral stability of the structure at the connection between the outer web and the root of the cantilever; the diagonal brace of the hollow-web truss adopts angle steel, and is equipped with high-strength bolts to ensure the connection strength, and is equipped with filling plates to ensure the rigidity; the inclined bottom plate of the cantilever box chamber can adopt two structural types: non-perforated and perforated. The structure of the large-cantilever steel box girder not only ensures sufficient lateral rigidity, but also has a light structure and a unified cantilever for the entire bridge, which is convenient for factory construction. It is suitable for both equal-height steel box girder bridges and variable-height and variable-width steel box girder bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an elevation view of a large cantilever steel box girder with an inclined bottom plate without openings according to the present invention.

[0015] Figure 2 It is a three-dimensional view of the large cantilever steel box girder with an inclined bottom plate without openings according to the present invention.

[0016] Figure 3 This is an elevation view of a large cantilever steel box girder with an inclined bottom plate opening according to the present invention.

[0017] Figure 4 The three-dimensional diagram of the large cantilever steel box girder with inclined bottom plate opening of the present invention.

[0018] Figure 5 It is a structural schematic diagram of the diagonal brace assembly in the present invention.

[0019] Figure 6 for Figure 5 Cross-section view of AA.

[0020] Figure 7 for Figure 5 Cross-section of the BB.

[0021] Figure 8 It is a schematic structural diagram of multiple groups of diagonal brace components in the present invention arranged in an X shape.

[0022] Fig. 9 for Figure 1 and Figure 3 Schematic diagram of the structure at A in the middle.

[0023] Fig.10 for Fig. 9 Cross-section of CC.

[0024] Fig.11 for Fig. 9 Cross-section of DD.

[0025] The parts in the figure are numbered as follows:

[0026] 1 Top Plate

[0027] 2 Bottom plate

[0028] 3 Medial abdominal plate

[0029] 4 Outer belly plate

[0030] 5 Main compartment partition

[0031] 6 inclined bottom plate

[0032] 7. Lifting arm belly plate

[0033] 8. Transverse partition of boom box room

[0034] 9 Top plate longitudinal stiffening ribs

[0035] 10 Bottom plate longitudinal stiffening ribs

[0036] 11 Inner web longitudinal stiffening ribs

[0037] 12 First longitudinal stiffening rib of outer web

[0038] 13 Cantilever arm web longitudinal stiffening rib

[0039] 14 Longitudinal stiffening ribs of inclined bottom plate

[0040] 15 Second longitudinal stiffening rib of outer web

[0041] 16 Transverse diaphragm and belly plate

[0042] 17 Transverse diaphragm flange plate

[0043] 18 diagonal brace

[0044] 19-node plate

[0045] 20 filler plates

[0046] 21 High Strength Bolts

[0047] 22 Stiffener web

[0048] 23 Stiffener flange plate. DETAILED DESCRIPTION

[0049] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that those skilled in the art can more clearly understand how to practice the present invention. Although the present invention is described in conjunction with its preferred specific embodiments, these embodiments are only illustrative, rather than limiting the scope of the present invention.

[0050] See also Figures 1 to 4 A large cantilever steel box girder mainly includes a top plate 1, a bottom plate 2, an inner web plate 3, an outer web plate 4, a main box chamber transverse partition plate 5, an inclined bottom plate 6, a cantilever web plate 7, and a cantilever box chamber transverse partition plate 8.

[0051] The inner part of the top plate 1, the bottom plate 2, the inner web 3, the outer web 4, and the main box chamber transverse diaphragm 5 constitute the main box chamber. The main box chamber mainly meets the requirements of bearing the longitudinal bending, shearing and torsion of the structure. According to the beam height, the main box chamber transverse diaphragm 5 can adopt a solid web transverse diaphragm or a structure combining a solid web transverse diaphragm and a hollow web truss.

[0052] The outer part of the top plate 1, the inclined bottom plate 6, the boom web 7, the outer web 4, and the boom box transverse partition 8 constitute the boom box, and the inner side of the inclined bottom plate 6 is welded to the outer side of the outer web 4. The boom box mainly meets the structural requirements of a wider beam width and the lateral force requirements of the structure. The entire bridge of the boom box remains unchanged, and the boom box transverse partition 8 adopts a structure combining a solid web transverse partition and a hollow web truss.

[0053] Among them, a plurality of top plate longitudinal stiffening ribs 9 are provided on the inner side surface of the top plate 1, a plurality of bottom plate longitudinal stiffening ribs 10 are provided on the inner side surface of the bottom plate 2, more than two inner web longitudinal stiffening ribs 11 and more than two outer web first longitudinal stiffening ribs 12 are provided on the inner side surfaces of the inner web 3 and the outer web 4, respectively, and more than one cantilever web longitudinal stiffening rib 13 is provided on the inner side surface of the cantilever arm web 7. The inner side surface refers to the side facing the box chamber.

[0054] The inclined bottom plate 6 can be of two types: a non-perforated structure and a perforated structure. If a non-perforated structure is adopted, see 1 and Figure 2 , the inner side of the inclined bottom plate 6 needs to be provided with inclined bottom plate longitudinal stiffening ribs 14. If an open hole structure is adopted, see Figure 3 and Figure 4 The opening position and shape of the inclined bottom plate 6 need to be determined according to the actual structural stress.

[0055] Since the steel box girder adopts a large cantilever structure, the root of the cantilever is subjected to greater force, and the outer web 4 has greater out-of-plane stress and deformation. In order to increase its out-of-plane stiffness and maintain the lateral stability of the structure, an outer web second longitudinal stiffening rib 15 is provided on the inner side surface of the outer web 4, and the outer web second longitudinal stiffening rib 15 is arranged corresponding to the inner side edge of the inclined bottom plate 6.

[0056] In this embodiment, the main box chamber transverse partition 5 and the boom box chamber transverse partition 8 both adopt a structure combining a solid-web transverse partition and a hollow-web truss.

[0057] This is explained below. The main box room diaphragm 5 and the boom box room diaphragm 8 both include a diaphragm web 16, a diaphragm flange 17, and multiple groups of diagonal brace assemblies. The diaphragm web 16 is the main body of the diaphragm. A hole is opened on the diaphragm web 16 as a truss setting area. The diaphragm flange 17 is set along the edge of the hole. Multiple groups of diagonal brace assemblies are set in the hole. Multiple groups of diagonal brace assemblies constitute a hollow truss. Each group of diagonal brace assemblies includes a diagonal brace 18 and a node plate 19. The two ends of the diagonal brace 18 are connected to the diaphragm flange 17 through the node plate 19. Among them, the solid-web diaphragm, that is, the diaphragm web 16, has a width and height that change synchronously with the width and height of the bridge. The hollow truss remains uniform throughout the bridge, which is convenient for factory mass production.

[0058] Furthermore, under the action of external load, the diagonal brace 18 is subjected to large axial force and bending moments at both ends, and the conventional diagonal brace often adopts a channel steel section, which has very small out-of-plane stiffness and is difficult to meet the stability requirements. Therefore, the diagonal brace 18 adopts angle steel to solve this problem. Figures 5 to 7 For each diagonal brace assembly, two diagonal braces 18 are arranged back to back, and the two ends are connected to two node plates 19 through high-strength bolts 21 to form a diagonal brace assembly. Each diagonal brace assembly is connected to the diaphragm flange plate 17 through the node plate 19. The high-strength bolts 21 can ensure the connection strength between the diagonal brace 18 and the node plate 19. Among them, more than two filling plates 20 are arranged between the two diagonal braces 3 of some diagonal brace assemblies, and the filling plates 20 can further ensure the rigidity of the diagonal brace assembly; the adjacent ends of adjacent diagonal brace assemblies can share the node plate 19.

[0059] Furthermore, since steel box continuous beam bridges and composite steel box continuous beam bridges often use variable height sections, the mid-span beam height is lower than the beam height at the support point. According to different beam heights, multiple groups of diagonal brace components of the main box room diaphragm 5 can be arranged in a V-shape or an X-shape in the holes of the diaphragm web 16, that is, a V-shaped or X-shaped open-web truss can be formed. Figures 1 to 3 If the beam height is not high, the main box room diaphragm 5 of the whole bridge only adopts the main box room diaphragm 5 of the V-shaped hollow truss. If the beam height is high, the main box room diaphragm 5 of the whole bridge not only adopts the main box room diaphragm 5 of the V-shaped hollow truss, but also adopts the main box room diaphragm 5 of the X-shaped hollow truss. The main box room diaphragm 5 of the V-shaped hollow truss is shown in FIG. Figures 1 to 3 , X-shaped hollow truss main box room transverse partition 5 see Figure 8 .

[0060] In this embodiment, the top plate longitudinal stiffening ribs 9 and the inclined bottom plate longitudinal stiffening ribs 14 are both U-ribs.

[0061] In this embodiment, the bottom plate longitudinal stiffening ribs 10, the inner web longitudinal stiffening ribs 11, the outer web first longitudinal stiffening ribs 12, and the cantilever web longitudinal stiffening ribs 13 are plate-shaped.

[0062] In this embodiment, see Figures 9 to 11 The second longitudinal stiffening rib 15 of the outer web is T-shaped, and includes a stiffening rib web 21 and a stiffening rib flange plate 23. The stiffening rib web 21 is perpendicular to the outer web 4, and one side of the stiffening rib web 21 is connected to the inner side of the outer web 4. The stiffening rib flange plate 23 is parallel to the outer web 4 and connected to the other side of the stiffening rib web 21.

[0063] This large cantilever steel box girder is suitable for both equal-height steel box girders and variable-height and variable-width steel box girders. For variable-height and variable-width steel box girders, the structural requirements of variable height and width are achieved through the main box chamber, and the cantilever box chamber remains unchanged throughout the bridge. During construction, the main box chamber and the cantilever box chamber are processed separately, and the cantilever box chambers of the entire bridge are unified, which is convenient for factory construction.

[0064] It should be noted that the fully described invention may also have a variety of variations and modifications, and is not limited to the specific embodiments described above. The above embodiments are merely illustrative of the invention, not limiting thereof. In short, the scope of protection of the invention should include those variations or substitutions and modifications that are obvious to a person of ordinary skill in the art.

Claims

1. A large cantilever steel box girder, characterized in that: It includes top plate, bottom plate, inner web plate, outer web plate, main box room transverse diaphragm, inclined bottom plate, cantilever arm web plate, cantilever arm box room transverse diaphragm, top plate longitudinal stiffening rib, bottom plate longitudinal stiffening rib, inner web longitudinal stiffening rib, outer web first longitudinal stiffening rib, outer web second longitudinal stiffening rib; The inner part of the top plate, the bottom plate, the inner web, the outer web and the main box chamber transverse partition constitute the main box chamber, the outer part of the top plate, the inclined bottom plate, the cantilever arm web, the outer web and the cantilever arm box chamber transverse partition constitute the cantilever arm box chamber, the inner side edge of the inclined bottom plate is welded to the outer side of the outer web, the inner side surface of the top plate is provided with a top plate longitudinal stiffening rib, the inner side surface of the bottom plate is provided with a bottom plate longitudinal stiffening rib, the inner side surfaces of the inner web and the outer web are respectively provided with an inner web longitudinal stiffening rib and an outer web first longitudinal stiffening rib, and the inner side surface of the outer web is provided with an outer web second longitudinal stiffening rib corresponding to the inner side edge of the inclined bottom plate; The cantilever box room diaphragm includes a diaphragm web, a diaphragm flange plate, and a diagonal brace assembly. A hole is opened on the diaphragm web, and the diaphragm flange plate is arranged along the edge of the hole. Multiple groups of diagonal brace assemblies are arranged in the holes of the diaphragm web. Each group of diagonal brace assemblies includes a diagonal brace, a node plate, and high-strength bolts. The diagonal brace is an angle steel. The two diagonal braces of each group of diagonal brace assemblies are arranged back to back, and the two ends are respectively connected to the two node plates by high-strength bolts, and the two node plates are connected to the diaphragm flange plate.

2. The large cantilever steel box girder according to claim 1 is characterized in that: The main box chamber diaphragm also includes a diaphragm web, a diaphragm flange plate, and a diagonal brace assembly.

3. The large cantilever steel box girder according to claim 2 is characterized in that: The multiple groups of diagonal bracing components of the main chamber transverse partition are arranged in a V-shape or an X-shape in the holes of the transverse partition web.

4. The large cantilever steel box girder according to claim 1 is characterized in that: The main chamber diaphragm is a solid-belly diaphragm.

5. The large cantilever steel box girder according to claim 1 is characterized in that: It also includes longitudinal stiffening ribs of the web of the cantilever arm, and the inner side surface of the web of the cantilever arm is provided with the longitudinal stiffening ribs of the web of the cantilever arm.

6. The large cantilever steel box girder according to claim 1, characterized in that: The second longitudinal stiffening rib of the outer web is T-shaped, and the second longitudinal stiffening rib of the outer web includes a stiffening rib web and a stiffening rib flange plate. The stiffening rib web is perpendicular to the outer web, and one side of the stiffening rib web is connected to the inner side of the outer web. The stiffening rib flange plate is parallel to the outer web and connected to the other side of the stiffening rib web.

7. The large cantilever steel box girder according to any one of claims 1 to 6, characterized in that: It also includes longitudinal stiffening ribs of the inclined bottom plate, and the inner side surface of the inclined bottom plate is provided with the longitudinal stiffening ribs of the inclined bottom plate.

8. The large cantilever steel box girder according to any one of claims 1 to 6, characterized in that: The inclined bottom plate is provided with holes.

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