Novel structure for improving anti-cracking performance of hogging moment area of corrugated steel web combined box girder

Abstract

The utility model relates to the field of bridges, and aims to provide a novel structure for improving the anti-cracking performance of a hogging moment area of a corrugated steel web combined box girder, which comprises the corrugated steel web combined box girder and a bridge deck paved at the top of the corrugated steel web combined box girder, the corrugated steel web combined box girder comprises a groove-shaped steel girder and a concrete panel erected on the top of the groove-shaped steel girder, the concrete panel comprises an anti-bending flat plate and an anti-bending arch plate, reinforcing meshes are embedded in the anti-bending flat plate and the anti-bending arch plate, the middle of the anti-bending arch plate is arched upwards, and arch feet are further arranged at the left end and the right end of the anti-bending arch plate. The anti-bending flat plates are arranged at intervals, each anti-bending arch plate is clamped between the lower portions of every two adjacent anti-bending flat plates, and anti-shearing connecting pieces for transmitting shearing force are further connected between the tops of the arch feet and the bottoms of the corresponding anti-bending flat plates. According to the corrugated steel web combined box girder, the anti-cracking form of a traditional corrugated steel web combined box girder is improved, and cracks of a bridge deck slab in a hogging moment area are effectively overcome.

Description

Technical Field

[0001] The utility model relates to the field of bridges, in particular to a novel structure for improving the anti-cracking performance of a negative bending moment zone of a composite box girder with corrugated steel webs. Background Art

[0002] A composite box girder bridge with corrugated steel webs, also known as a PC bridge with corrugated steel webs, is a box girder bridge with corrugated steel plates replacing concrete webs. Its notable feature is that 10-20 mm thick corrugated steel plates replace 30-80 cm thick concrete webs, reducing the bridge's deadweight while maintaining load-bearing capacity. Due to the structural characteristics of the bridge structure, the bridge is subject to positive and negative bending moments in different areas. Positive bending moments involve tension at the bottom and compression at the top, resulting in a "concave" shape; negative bending moments involve tension at the top and compression at the bottom, resulting in a "convex" shape. In the negative bending moment region of the bridge, the concrete top slab is subjected to tension while the corrugated steel web box girder is subjected to compression. This load-bearing structure can easily lead to cracking in the concrete top slab, directly impacting traffic safety. Therefore, prestressing the concrete slab in this negative bending moment region is necessary to mitigate the effects of concrete top slab cracking.

[0003] To address the cracking problem in the concrete top slabs of composite box girder bridges with corrugated steel webs, three solutions are commonly used. First, the crack width of the concrete top slab is limited by increasing the reinforcement ratio of ordinary steel bars in the concrete top slab. Second, prestressing the concrete top slab in the negative moment zone is achieved through post-tensioning, i.e., prestressing the concrete top slab after pouring to offset the tensile stress generated in the negative moment zone. Third, construction measures are used to improve the stress conditions of the concrete top slab in the negative moment zone to overcome the adverse effects of the negative moment zone.

[0004] However, increasing the reinforcement ratio of ordinary steel bars can only limit the development of cracks but cannot solve the cracking problem. There is still a lack of systematic research on construction methods to improve stress, and many difficulties remain in construction design. Currently, the most commonly used method for applying prestress is post-tensioning. This method can easily cause the bearing capacity of the negative bending moment zone of long-span bridges to exceed the limit, requiring the addition of very thick steel plates to offset the limit. At the same time, a large amount of prestress will be consumed in the corrugated steel web, resulting in a reduction in the prestress reserve of the concrete top slab and easily leading to the problem of compressive buckling of the box girder. Utility Model Content

[0005] The purpose of this utility model is to provide a new structure for improving the anti-cracking performance of the negative bending moment zone of the composite box girder with corrugated steel webs, which improves the anti-cracking form of the traditional composite box girder with corrugated steel webs and effectively overcomes the generation of cracks in the bridge deck in the negative bending moment zone.

[0006] The purpose of the utility model is achieved through the following technical solutions:

[0007] A novel structure for improving the crack resistance of a negative bending moment zone of a composite box girder with a corrugated steel web, comprising a composite box girder with a corrugated steel web and a bridge deck paved on top of the composite box girder with a corrugated steel web. The composite box girder with a corrugated steel web comprises a channel steel beam and a concrete panel erected on top of the channel steel beam. The concrete panel comprises a plurality of bending flat plates for bearing the positive bending moment of the bridge and a plurality of bending arch plates for bearing the negative bending moment of the bridge. Steel mesh is embedded in both the bending flat plates and the bending arch plates. The bending arch plates arch upward in the middle and are provided with longitudinally extending arch feet at both ends.

[0008] The anti-bending flat plates are arranged in sequence at intervals on the left and right, and each anti-bending arch plate is sandwiched between the bottoms of two adjacent anti-bending flat plates. A shear connector for transmitting shear force is also connected between the top of the arch foot and the bottom of the corresponding anti-bending flat plate.

[0009] Compared with the prior art, the advantages of the present invention are:

[0010] 1. The coordination of the bending-resistant flat plate and the bending-resistant arch plate makes the overall stress of the composite box girder with corrugated steel webs evenly dispersed, reducing the stress concentration phenomenon. In addition, the through-connection of the steel diaphragm and the steel mesh in the bending-resistant arch plate ensures stress coordination between the structures, thereby improving the integrity and crack resistance of the structure.

[0011] 2. The shear force of the composite box girder with corrugated steel webs is effectively transmitted through the cooperation of shear connectors, arch feet and bending-resistant plates, avoiding deformation of the composite box girder with corrugated steel webs due to concentrated shear force, thereby preventing structural cracks caused by shear force and further improving the structural integrity and crack resistance.

[0012] 3. By inserting prestressed steel bars between the arch feet, the tensile stress at the top of the negative bending moment area is effectively offset, thereby avoiding cracking of the bending arch plate, improving the prestress reserve of the structure, and preventing cracks from occurring in the negative bending moment area of ​​the bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of a novel structural embodiment 1 of the utility model for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs;

[0014] Figure 2 This is a schematic structural diagram of a novel structural embodiment 2 of the utility model for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs;

[0015] Figure 3 This is a simplified structural diagram of the steel partition of the utility model;

[0016] Figure 4This is a front-to-back sectional view of the composite box girder with corrugated steel webs of the present invention;

[0017] Figure 5 This is a schematic diagram of the structure of the utility model in which the corrugated steel web passes through the bending-resistant arch plate;

[0018] Figure 6 This is a schematic diagram of the penetration entrance of the utility model;

[0019] Figure 7 It is a structural schematic diagram of the shear-resistant connector of the utility model.

[0020] Explanation of numbers: 1 bridge deck, 2 channel steel beam, 21 flat steel bottom plate, 22 corrugated steel web, 23 steel partition, 231 through hole, 232 passage, 24 flat steel top plate, 31 bending-resistant flat plate, 32 bending-resistant arch plate, 301 steel mesh, 321 arch foot, 322 passage, 4 shear connector, 41 back wall, 42 shear reinforcement, 5 prestressed reinforcement, 6 construction gravel. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and embodiments:

[0022] like Figure 1-7 FIG. 1 is a schematic diagram of an embodiment of a novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs provided by the present invention:

[0023] A novel structure for improving the crack resistance of a corrugated steel web composite box girder in a negative bending moment zone, comprising a corrugated steel web composite box girder and a bridge deck 1 paved on top of the corrugated steel web composite box girder. The corrugated steel web composite box girder comprises a channel steel beam 2 and a concrete panel erected on top of the channel steel beam 2. The concrete panel comprises a plurality of bending flat plates 31 for bearing the positive bending moment of the bridge and a plurality of bending arch plates 32 for bearing the negative bending moment of the bridge. Steel mesh 301 is embedded in each of the bending flat plates 31 and the bending arch plates 32. The bending arch plates 32 arch upward from the middle and are provided with longitudinally extending arch feet 321 at their left and right ends.

[0024] The anti-bending flat plates 31 are arranged in sequence at intervals on the left and right, and each anti-bending arch plate 32 is sandwiched between the bottoms of two adjacent anti-bending flat plates 31, and a shear connector 4 for transmitting shear force is connected between the top of the arch foot 321 and the bottom of the corresponding anti-bending flat plate 31.

[0025] The channel steel beam 2 includes a flat steel bottom plate 21 and two corrugated steel webs 22 extending left and right. The two corrugated steel webs 22 are spaced apart from each other, and the bottoms of the corrugated steel webs 22 are fixed to the upper surface of the flat steel bottom plate 21.

[0026] A plurality of steel partitions 23 are provided between the two corrugated steel webs 22 , and each steel partition 23 is connected between each arch foot 321 and the flat steel bottom plate 21 in a one-to-one correspondence.

[0027] Each steel partition 23 extends upward to the interior of the anti-bending arch plate 32 , and a plurality of through holes 231 are provided on the upper portion of the steel partition 23 , through which the steel mesh 301 in the anti-bending arch plate 32 passes.

[0028] A passage 232 is provided in the middle of the steel partition 23 for maintenance personnel to pass through.

[0029] like Figure 2 The figure shows a schematic diagram of Example 2 of the present utility model. In this Example 2, a flat steel top plate 24 is further provided below the anti-bending arch plate 32. The left and right sides of the flat steel top plate 24 are respectively connected to the corresponding steel partitions 23, and the front and rear sides of the flat steel top plate 24 are respectively connected to the front and rear two corrugated steel webs 22. The flat steel bottom plate 21, the corrugated steel web 22, the steel partition 23 and the flat steel top plate 24 form a closed box-shaped structure. The horizontal thrust of the arch foot 321 is overcome by the flat steel top plate 24, so that the anti-bending arch plate 32 obtains prestressing stress.

[0030] The left and right ends of the flat steel top plate 24 are fixed to the corresponding steel partition plates 23 by welding.

[0031] The shear connector 4 includes a back wall 41 provided between the arch foot 321 and the bending plate 31 and a plurality of shear steel bars 42 embedded in the back wall 41;

[0032] The back wall 41 is a concrete structure extending forward and backward, and the concrete grade thereof is preferably consistent with that of the anti-bending arch plate 32 or the anti-bending flat plate 31 .

[0033] A plurality of shear reinforcement bars 42 are arranged at intervals along the extending direction of the back wall 41 .

[0034] The shear steel bars 42 extend longitudinally, and their upper ends extend into the bending flat plate 31 and are connected to the steel mesh 301 in the bending flat plate 31. The lower ends of the shear steel bars 42 extend downward into the bending arch plate 32 and are connected to the steel mesh 301 in the bending arch plate 32.

[0035] like Figure 1 The figure shows a schematic diagram of Example 1 of the present utility model. In this Example 1, a plurality of prestressed steel bars 5 are provided between the arch feet 321 at the left and right ends of the anti-bending arch plate 32. The horizontal thrust of the arch feet 321 is overcome by the prestressed steel bars 5, so that the anti-bending arch plate 32 obtains pre-compression stress.

[0036] The left and right ends of the prestressed steel bar 5 are anchored to the corresponding arch feet 321 through external anchors.

[0037] In some embodiments, in order to further increase the prestressing stress of the compression-resistant arch plate 32 , the flat steel top plate 24 and the prestressed steel bars 5 may be provided at the same time.

[0038] The top surface of the anti-bending arch plate 32 is paved with construction gravel 6 , and the top surface of the construction gravel 6 is flush with the top surface of the anti-bending flat plate 31 . The bridge deck 1 is paved on the top surfaces of the anti-bending flat plate 31 and the construction gravel 6 .

[0039] The anti-bending arch plate 32 is provided with a through-hole 322 matching the corrugated steel web 22 , and the upper end of the corrugated steel web 22 passes through the anti-bending arch plate 32 through the through-hole 322 .

[0040] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A novel structure for improving the anti-cracking performance of a composite box girder with a corrugated steel web in a negative bending moment zone, comprising a composite box girder with a corrugated steel web and a bridge deck (1) paved on top of the composite box girder with a corrugated steel web, characterized in that: The corrugated steel web composite box girder comprises a channel steel beam (2) and a concrete panel erected on the top of the channel steel beam (2), the concrete panel comprising a plurality of bending-resistant flat plates (31) for bearing the positive bending moment of the bridge and a plurality of bending-resistant arch plates (32) for bearing the negative bending moment of the bridge, a steel mesh (301) is embedded in both the bending-resistant flat plates (31) and the bending-resistant arch plates (32), and the bending-resistant arch plates (32) arch upward in the middle, and longitudinally extending arch feet (321) are further provided at the left and right ends of the bending-resistant arch plates (32); The anti-bending flat plates (31) are arranged in sequence at intervals on the left and right, and each anti-bending arch plate (32) is respectively sandwiched between the bottoms of two adjacent anti-bending flat plates (31), and a shear connector (4) for transmitting shear force is connected between the top of the arch foot (321) and the bottom of its corresponding anti-bending flat plate (31).

2. The novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs according to claim 1 is characterized by: The channel-shaped steel beam (2) comprises a flat steel bottom plate (21) and two corrugated steel webs (22) extending left and right, the two corrugated steel webs (22) are spaced apart from each other, and the bottoms of the corrugated steel webs (22) are fixed to the upper surface of the flat steel bottom plate (21); A plurality of steel partitions (23) are provided between the two corrugated steel webs (22), and each steel partition (23) is connected between each arch foot (321) and the flat steel bottom plate (21) in a one-to-one correspondence.

3. The novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs according to claim 2 is characterized by: Each steel partition (23) extends upward to the interior of the anti-bending arch plate (32), and a plurality of through holes (231) are provided on the upper portion of the steel partition (23), and the steel mesh (301) in the anti-bending arch plate (32) passes through the steel partition (23) through the through holes (231).

4. The novel structure for improving the anti-cracking performance of the negative moment zone of a composite box girder with corrugated steel webs according to claim 2 is characterized by: A passage (232) is provided in the middle of the steel partition (23) for easy passage of maintenance personnel.

5. The novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs according to claim 2 is characterized by: A flat steel top plate (24) is further provided below the bending-resistant arch plate (32). The left and right sides of the flat steel top plate (24) are respectively connected to the corresponding steel partition plates (23). The front and rear sides of the flat steel top plate (24) are respectively connected to the front and rear corrugated steel web plates (22). The flat steel bottom plate (21), the corrugated steel web plates (22), the steel partition plates (23) and the flat steel top plate (24) form a closed box-shaped structure.

6. The novel structure for improving the anti-cracking performance of the negative moment zone of a composite box girder with corrugated steel webs according to claim 1 is characterized by: The shear-resistant connector (4) includes a back wall (41) provided between the arch foot (321) and the bending-resistant flat plate (31), and a plurality of shear-resistant steel bars (42) pre-embedded in the back wall (41); The shear steel bars (42) extend longitudinally, with their upper ends extending into the bending-resistant flat plate (31) and connected to the steel mesh (301) in the bending-resistant flat plate (31), and their lower ends extending downward into the bending-resistant arch plate (32) and connected to the steel mesh (301) in the bending-resistant arch plate (32).

7. The novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs according to claim 1 is characterized by: A plurality of prestressed steel bars (5) are provided between the arch feet (321) at the left and right ends of the bending-resistant arch plate (32).

8. The novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs according to claim 1 is characterized by: The top surface of the anti-bending arch plate (32) is paved with construction gravel (6), the top surface of the construction gravel (6) is flush with the top surface of the anti-bending flat plate (31), and the bridge deck (1) is paved on the top surfaces of the anti-bending flat plate (31) and the construction gravel (6).

9. The novel structure for improving the anti-cracking performance of the negative bending moment zone of a composite box girder with corrugated steel webs according to claim 1 is characterized by: The anti-bending arch plate (32) is provided with a through-port (322) matching the corrugated steel web (22), and the upper end of the corrugated steel web (22) passes through the anti-bending arch plate (32) through the through-port (322).

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