Cavity leveling layer structure suitable for bridge longitudinal section transformation and construction method of cavity leveling layer structure

Abstract

The invention discloses a cavity leveling layer structure suitable for bridge longitudinal section transformation and a construction method thereof, belongs to the field of bridge engineering, and solves the problem that the dead weight of a box girder can be increased by adding a concrete leveling layer. The device comprises a box girder, a concrete leveling layer is arranged at the top of the box girder, and a plurality of hollow pipes are arranged in the concrete leveling layer side by side. The construction method comprises the following steps: cleaning sundries on the surface of the box girder structure to completely expose the top surface of the box girder; chiseling a notch in the top surface of the box girder, wherein the depth of the notch is based on the exposure of box girder steel bars; the vertical steel bars and the box girder steel bars are welded, and the notches are filled; longitudinal steel bars and transverse steel bars located on the lower portion of the concrete leveling layer are bound and fixed through vertical steel bars; hollow pipes are installed, and the hollow pipes are laid between the vertical steel bars; longitudinal steel bars and transverse steel bars located on the upper portion of the concrete leveling layer are bound and fixed through vertical steel bars; and pouring a concrete leveling layer. The self weight of the structure is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the field of bridge engineering, and in particular relates to a cavity leveling layer structure suitable for bridge longitudinal section reconstruction and a construction method thereof. Background Art

[0002] With the rapid development of the national economy and urban construction, the transportation system has also entered a period of great development. In the road longitudinal section reconstruction projects implemented for urban planning, old city renovation, and transportation upgrades, we often encounter bridges that have been in use for a short time and are in good condition, or have special functions that are not suitable for demolition. They need to have their vertical alignment adjusted.

[0003] For the existing concrete main beams, due to their high rigidity, the longitudinal section is generally modified by jacking and rotation, which can better adapt to the situation where the line shape after modification is a straight line; however, when the facade after modification is located on a vertical curve, jacking and rotation alone cannot meet the linear requirements of the road. In this case, it is necessary to change the thickness of the leveling layer and the pavement layer to achieve the fitting of the vertical curve.

[0004] When the difference between the new design deck elevation and the existing deck elevation within a box girder unit is within the range of -3cm to +18cm, the design requirements can be met by adding a concrete leveling layer or reducing the thickness of the existing deck pavement. However, when the height difference exceeds +18cm, adding a concrete leveling layer will inevitably increase the deadweight of the box girder. Once the design thickness is exceeded, the load on the bridge deck will exceed the design range, resulting in a reduction in the structural bearing capacity of the bridge. In severe cases, it may lead to bridge collapse. Furthermore, a thicker leveling layer will increase the complexity and time of construction.

[0005] In this context, there is an urgent need for a leveling layer structure with low deadweight, simple structure, convenient implementation and reliable connection, so as to achieve the purpose of reusing bridge structures and saving construction time and investment. Summary of the Invention

[0006] The purpose of the present invention is to provide a cavity leveling layer structure suitable for bridge longitudinal section reconstruction, so as to solve the problem that adding a concrete leveling layer will increase the deadweight of the box beam.

[0007] Another object of the present invention is to provide a construction method for a cavity leveling layer structure suitable for bridge longitudinal section reconstruction.

[0008] The technical solution of the present invention is: a cavity leveling layer structure suitable for bridge longitudinal section reconstruction, comprising a box beam, a concrete leveling layer provided on the top of the box beam, and a plurality of hollow tubes arranged side by side in the concrete leveling layer.

[0009] As a further improvement of the present invention, the hollow tubes are arranged along the longitudinal bridge direction.

[0010] As a further improvement of the present invention, vertical steel bars, longitudinal steel bars and transverse steel bars connected to each other are provided in the concrete leveling layer.

[0011] As a further improvement of the present invention, a plurality of notches are provided on the top of the box girder, the box girder reinforcement is exposed at the notches, and the vertical reinforcement is welded to the box girder reinforcement.

[0012] As a further improvement of the present invention, the hollow tube is made of PP material.

[0013] A construction method for a cavity leveling layer structure suitable for bridge longitudinal section reconstruction comprises the following steps: A. For existing bridges, first remove the asphalt layer on the bridge deck and remove the expansion joints. Then, lift or rotate the bridge to reconstruct it. Then, clean the debris on the surface of the box girder structure to fully expose the top surface of the box girder. Then, treat the top surface of the box girder. B. Cut a notch on the top surface of the box girder. The depth of the notch should be such that the box girder reinforcement is exposed. C. Weld the vertical steel bars to the box beam steel bars. After welding, fill the notches. D. Tie the longitudinal and transverse reinforcements at the bottom of the concrete leveling layer. Tie the longitudinal and transverse reinforcements at the bottom into a mesh and secure them with vertical reinforcements. E. Install the hollow pipe, which is laid between the vertical steel bars; F. Tie the longitudinal and transverse reinforcements on the upper part of the concrete leveling layer. Tie the upper longitudinal and transverse reinforcements into a mesh and secure them with vertical reinforcements. G. Pour the concrete leveling layer.

[0014] Furthermore, in step E, the diameter of the hollow tube is determined according to the actual thickness of the concrete leveling layer, the thickness of the concrete in the upper layer of the hollow tube is controlled to be 5-8 cm, and the thickness of the concrete in the lower layer of the hollow tube is controlled to be 5-6 cm.

[0015] The beneficial effects of the present invention are: 1. This invention utilizes a combined concrete and hollow tube structure, effectively reducing the structure's deadweight and improving the bridge's load-bearing capacity. The variable-thickness concrete leveling layer allows the bridge to better adapt to vertical curves after renovation, addressing renovation requirements that cannot be met by jacking and rotation alone, thus facilitating bridge renovation and utilization. The hollow tube diameter is selected based on the thickness of the concrete leveling layer. Even with thicker concrete leveling layers, the deadweight of the structure can be effectively controlled, reducing concrete usage.

[0016] 2. The present invention arranges the hollow tube in a steel frame consisting of vertical steel bars, longitudinal steel bars, and transverse steel bars, and uses the steel frame to limit its position to prevent the hollow tube from shifting and rotating under the action of pouring concrete and vehicles, thereby ensuring a reliable connection.

[0017] 3. The construction method of the present invention is simple, easy to implement and has good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic elevation diagram of a cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to the present invention; Figure 2 Schematic diagram of the plane of the notch in the present invention; Figure 3 for Figure 1 AA view in; Figure 4 for Figure 1 Enlarged view of part B in .

[0019] In the figure, 1. hollow tube; 2. longitudinal reinforcement; 3. transverse reinforcement; 6. vertical reinforcement; 7. concrete leveling layer; 8. box girder reinforcement; 9. box girder; 11. notch; 12. weld. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1-4 As shown, a cavity leveling layer structure suitable for bridge longitudinal section reconstruction includes a box girder 9, a concrete leveling layer 7 disposed on top of the box girder 9, and multiple hollow tubes 1 arranged side by side within the concrete leveling layer 7. The hollow tubes 1 are arranged along the longitudinal direction of the bridge and are made of PP.

[0022] The concrete leveling layer 7 is provided with interconnected vertical reinforcement 6, longitudinal reinforcement 2 and transverse reinforcement 3. The upper and lower parts of the concrete leveling layer 7 are both provided with reinforcement meshes consisting of longitudinal reinforcement 2 and transverse reinforcement 3.

[0023] A plurality of longitudinal notches 11 are provided on the top of the box beam 9 , and the longitudinal box beam reinforcement bars 8 are exposed at the notches 11 , and the vertical reinforcement bars 6 are welded to the box beam reinforcement bars 8 .

[0024] A construction method for a cavity leveling layer structure suitable for bridge longitudinal section reconstruction comprises the following steps: A. For existing bridges, first remove the asphalt layer on the bridge deck and remove the expansion joints. Then, lift or rotate the bridge. Then, clean the debris on the surface of the box girder structure to fully expose the top surface of the box girder 9. Then, use the "roughening, sandblasting, and cleaning" method to treat the top surface of the box girder 9 to improve the bonding strength between the leveling layer and it.

[0025] B. Cut a notch 11 with a width of 10 cm and a depth of 3.5 m on the top surface of the box girder 9 in the longitudinal direction. The depth of the notch 11 should be such that the box girder reinforcement 8 is exposed. The notches 11 are spaced 60 cm apart in the transverse direction of the bridge and are evenly arranged across the entire cross section. Derust the exposed box girder reinforcement 8, and then clean the notch 11 to avoid dust and oil stains.

[0026] C. After the notch 11 is processed, the vertical steel bars 6 connecting the leveling layer and the existing box girder bridge deck are welded. The vertical steel bars 6 use 12mm diameter three-grade fine-rolled threaded steel bars and are welded to the box girder steel bars 8. A single-sided weld 12 is used. The length of the weld 12 is not less than 12cm, the transverse spacing is 60cm, and the longitudinal spacing is the same as the spacing of the PP pipe 1. After the vertical connecting steel bars 6 are welded, C50 steel fiber concrete is used to fill the notch 11.

[0027] D. Tie up the longitudinal reinforcement 2 and transverse reinforcement 3 located at the bottom of the concrete leveling layer 7. The specifications of the longitudinal reinforcement 2 and transverse reinforcement 3 at the bottom are both first-class hot-rolled round steel bars with a diameter of 10 mm. The longitudinal and transverse spacing are both 10 cm. The longitudinal reinforcement 2 and transverse reinforcement 3 at the bottom are tied into a net and fixed with vertical reinforcement 6.

[0028] E. Install hollow tube 1. Carbon fiber reinforced composite materials can be used to meet the bridge deck's rigidity and impact resistance requirements. Hollow tube 1 is laid between vertical steel bars 6, with a minimum clearance of 6 cm. The diameter of hollow tube 1 is determined by the actual thickness of the concrete leveling layer 7. The concrete thickness of the upper layer of hollow tube 1 is controlled between 5-8 cm, and the concrete thickness of the lower layer of hollow tube 1 is controlled between 5-6 cm. If the thickness requirements are met, choose a larger diameter pipe.

[0029] F. Tie up the longitudinal reinforcement 2 and transverse reinforcement 3 located on the upper part of the concrete leveling layer 7. The specification of the upper longitudinal reinforcement 2 is a first-class hot-rolled round steel bar with a diameter of 10 mm, and the specification of the transverse reinforcement 3 is a third-class fine-rolled threaded steel bar with a diameter of 16 mm. The longitudinal and transverse spacings are both 10 cm. The upper longitudinal reinforcement 2 and transverse reinforcement 3 are tied into a net and fixed with vertical reinforcement 6.

[0030] G. Pour concrete leveling layer 7.

Claims

1. A cavity leveling layer structure suitable for bridge longitudinal section reconstruction, comprising a box girder with a concrete leveling layer provided on top of the box girder, characterized in that: A plurality of hollow tubes (1) are arranged side by side in the concrete leveling layer (7).

2. The cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to claim 1 is characterized in that: The hollow tubes (1) are arranged along the longitudinal bridge direction.

3. The cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to claim 1 or 2, characterized in that: The concrete leveling layer (7) is provided with interconnected vertical steel bars (6), longitudinal steel bars (2), and transverse steel bars (3).

4. The cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to claim 3 is characterized by: The top of the box girder (9) is provided with a plurality of notches (11), the box girder reinforcement (8) is exposed at the notches (11), and the vertical reinforcement (6) is welded to the box girder reinforcement (8).

5. The cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to claim 1 is characterized in that: The hollow tube (1) is made of PP material.

6. A construction method for a cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to claim 4, characterized in that The following steps are involved: A. For existing bridges, first remove the asphalt layer on the bridge deck and remove the expansion joints, then perform jacking or rotation modification on the bridge, then clean the debris on the surface of the box girder structure to fully expose the top surface of the box girder (9), and then perform treatment on the top surface of the box girder (9); B. chiseling a notch (11) on the top surface of the box beam (9), the depth of the notch (11) being such that the box beam reinforcement (8) is exposed; C. Welding the vertical steel bars (6) to the box beam steel bars (8). After welding, the notches (11) are filled; D. Binding the longitudinal steel bars (2) and transverse steel bars (3) located at the lower part of the concrete leveling layer (7), binding the lower longitudinal steel bars (2) and transverse steel bars (3) into a mesh, and fixing them with vertical steel bars (6); E. Installing the hollow tube (1), which is laid between the vertical steel bars (6); F. Binding the longitudinal steel bars (2) and transverse steel bars (3) located on the upper portion of the concrete leveling layer (7), binding the upper longitudinal steel bars (2) and transverse steel bars (3) into a mesh, and fixing them with vertical steel bars (6); G. Pour the concrete leveling layer (7).

7. The construction method of a cavity leveling layer structure suitable for bridge longitudinal section reconstruction according to claim 6, characterized in that: In step E, the diameter of the hollow tube (1) is determined according to the actual thickness of the concrete leveling layer (7), the thickness of the concrete in the upper layer of the hollow tube (1) is controlled to be 5-8 cm, and the thickness of the concrete in the lower layer of the hollow tube (1) is controlled to be 5-6 cm.

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