A shortened steel structure bridge temperature across structure
By setting longitudinal joints and mid-span expansion joints in the mid-span section of the beam, the problem of temperature span coordination with track deformation in long-span ballastless track bridges was solved, achieving structural stress optimization and investment savings, and is applicable to the design of long-span bridges.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA RAILWAY SHANGHAI DESIGN INST GRP CO LTD
- Filing Date
- 2025-06-10
- Publication Date
- 2026-06-02
AI Technical Summary
Existing long-span ballastless track bridges have high requirements for track deformation coordination over temperature span, resulting in high cost of track temperature regulators and strict alignment requirements, making them difficult to apply in long-span bridges.
A longitudinal joint is set in the mid-span of the beam, and a mid-span expansion joint is installed at the joint. The bending moment and shear force are transferred through the mid-span expansion joint, allowing the beam to move along the longitudinal direction of the bridge and optimizing the stress on the structure.
It shortens the temperature span of steel structure bridges, saves investment, ensures coordinated deformation between the beam and the ballastless track, avoids the use of track temperature regulators, improves the stress on the beam and track, and is suitable for the design of long-span bridges.
Smart Images
Figure CN224314023U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of bridge structure design technology, specifically to a structure for shortening the temperature span of a steel bridge. Background Technology
[0002] With the development of high-speed railways and rail transit, the application of ballastless track bridges is increasing, resulting in a large number of long-span ballastless track bridges. However, ballastless tracks have high requirements for temperature spans.
[0003] like Figure 1 As shown, the temperature span of the existing steel structure and steel-concrete composite continuous beam is the length L from the fixed support to the beam end. If this length exceeds the normal temperature span, it can easily cause incoordination in the deformation of the beam and the ballastless track, requiring adjustment through a track temperature regulator. However, track temperature regulators are not only expensive, increasing project investment, but also have high requirements for track alignment. In fact, the inability to set track temperature regulators for long-span bridges can even affect the overall track alignment. Summary of the Invention
[0004] The purpose of this utility model is to address the shortcomings of the prior art by providing a structure that shortens the temperature span of a steel bridge. By setting a longitudinal joint in the mid-span of the beam, the beams on both sides of the joint can move along the bridge direction. The bending moment and shear force are transferred by the mid-span expansion joint located at the joint, thus optimizing the structural stress and greatly shortening the temperature span of the steel bridge. At the same time, it ensures that the deformation of the beam and the ballastless track are coordinated.
[0005] The objective of this utility model is achieved through the following technical solution:
[0006] A shortening steel bridge temperature span structure includes a main pier, side piers, and a beam body. The beam body is supported on the main pier and side piers. The beam body includes a mid-span section and side span sections. A ballastless track is installed above the beam body. The beam body is characterized by: a longitudinal joint is provided in the mid-span section to allow the beam body on both sides of the mid-span section to move along the bridge direction; a mid-span expansion joint is provided at the location of the joint; when the beam body extends or contracts, the mid-span expansion joint achieves longitudinal expansion and contraction at the mid-span position.
[0007] The mid-span expansion joint is installed on the top plate, bottom plate and web of the beam.
[0008] The mid-span telescopic device located on the top plate, the mid-span telescopic device located on the bottom plate, and the mid-span telescopic device located on the web plate are arranged on different elevations on both sides of the mid-span midline.
[0009] The mid-span expansion joint includes a first expansion member and a second expansion member. The first expansion member is located on the adjacent end face of the beam on both sides of the joint. Both first expansion members are provided with upper and lower bends. The second expansion member is engaged with the bends of the first expansion members on both sides.
[0010] The first expansion joint and the second expansion joint are embedded in their respective beam bodies by pre-embedded parts.
[0011] The beam in the mid-span section is fixed to the main pier below it.
[0012] The beam of the side span is connected to the side pier below it by a longitudinally movable bearing.
[0013] The advantages of this utility model are:
[0014] 1) The structural stress was optimized, which greatly shortened the temperature span of the steel structure bridge.
[0015] 2) Shortening the temperature span greatly improves the stress on the beam and rail, ensuring that the deformation of the beam and the ballastless track is coordinated without the need for a rail temperature regulator, thus saving investment; because there is no rail temperature regulator, the alignment of long-span steel structure bridges is no longer restricted, which is more beneficial for railway and rail transit route selection.
[0016] 3) Shortening the temperature span saves on the fixed support at the middle support point, thus saving investment.
[0017] 4) Because there is an expansion joint in the mid-span of the bridge, the expansion and contraction of the main beam caused by temperature can be eliminated by the expansion joint, and the pier will not be affected by the temperature rise and fall of the main beam. The pier-beam connection is not affected by the height of the pier.
[0018] 5) The structure is simple and reasonable, and can be embedded into the beam during prefabrication, making construction convenient and suitable for widespread application. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the temperature span range for large-span continuous steel beams in existing technologies.
[0020] Figure 2 This is a schematic diagram of the structure of the present invention (including the temperature range).
[0021] Figure 3 This is a mid-section elevation view of the present invention;
[0022] Figure 4 This is a mid-span elevation view of the top slab of this utility model;
[0023] Figure 5 This is a mid-span elevation view of the base plate of this utility model;
[0024] Figure 6 The bending moment diagram is shown for a large-span continuous steel beam in the existing technology.
[0025] Figure 7 This is the bending moment diagram of this utility model;
[0026] Figure 8 This is a schematic diagram showing the temperature span range and the expansion and contraction direction of the main beam in existing large-span steel continuous beam structures.
[0027] Figure 9 This is a schematic diagram showing the temperature range and the direction of expansion and contraction of the main beam of this utility model. Detailed Implementation
[0028] The features and other related features of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate the understanding of those skilled in the art:
[0029] like Figure 1-9 As shown in the figure, the numbers 1-22 represent: 1. Main pier, 2. Beam body, 3. Pier-beam fixed joint, 4. Portable bearing in the direction of bridge movement, 5. Temperature span, 6. Mid-span expansion joint, 7. Top slab, 8. Bottom slab, 9. Pavement layer, 10. Ballastless track, 11. Top slab expansion embedded part, 12. Bottom slab expansion embedded part, 13. Top slab expansion component, 14. Left top slab, 15. Right top slab, 16. Left bottom slab, 17. Right bottom slab, 18. Bottom slab expansion component, 19. Bottom slab expansion component, 20. Joint, 21. Joint, 22.
[0030] Example: Figures 1 to 9 As shown, the shortened temperature span structure of the steel bridge in this embodiment includes a main pier 1 and a beam 2, wherein the beam 2 is supported on the main pier 1 and the side piers. The beam between the two main piers 1 is the mid-span section, and the beam between the main pier and the side pier is the side span section. A pavement layer 9 is provided above the beam 2, and a ballastless track 10 is provided on the pavement layer 9.
[0031] like Figure 2 As shown, in this embodiment, the main pier 1 and the beam 2 are fixed at the pier-beam connection point 3, and the beam 2 and the side pier are connected by a longitudinally movable bearing 4. A joint is provided at the mid-span, and a mid-span expansion joint 6 is installed at the joint. When the beam 2 deforms, for example, when the beam 2 elongates or contracts due to temperature deformation caused by temperature changes, the mid-span expansion joint 6 achieves longitudinal expansion at the mid-span position, thereby reducing the length of the temperature span 5. (Comparison) Figure 1 and Figure 2 It can be seen that the length of the temperature span 5 in this embodiment is significantly smaller than the temperature span length L in the prior art.
[0032] like Figure 3As shown, the beam 2 includes a top plate 7, a bottom plate 8, and a web (not shown in the elevation view). Mid-span expansion joints 6 are provided on the bottom plate 8, the top plate 7, and the web. Taking the figure as an example, the mid-span expansion joint 6 includes a top plate expansion embedded part 11, a bottom plate expansion embedded part 12, and a web expansion embedded part, thereby ensuring that the entire beam 2 can achieve longitudinal expansion and contraction.
[0033] like Figure 4 As shown, taking the illustrated direction as an example, the top plate 7 of beam 2 is divided into a left top plate 15 and a right top plate 16 due to the presence of a fracture joint 22. The top plate expansion joint 11 at the fracture joint 22 includes a top plate expansion joint 14 serving as the first expansion joint and a top plate expansion joint 13 serving as the second expansion joint. Top plate expansion joints 14 are located on both sides of the beam end face of the fracture joint 22, and each top plate expansion joint 14 has hooks formed by bending on both the upper and lower sides. The top plate expansion joint 13 has buckles adapted to the top plate expansion joint 14. By using the top plate expansion joint 13 to engage the top plate expansion joints 14 on both sides, shear force and bending moment can be transferred, while ensuring free longitudinal displacement of the expansion joints and the top plate 7.
[0034] like Figure 5 As shown, the bottom plate 8 is also divided into a left bottom plate 17 and a right bottom plate 18 by setting a joint 21. At the position of the joint 21, there are bottom plate expansion members 19 and 20. The two are connected to each other to transfer bending moment and shear force, ensuring the free displacement of the expansion members and the bottom plate of the beam in the longitudinal direction.
[0035] Similarly, the same mid-span expansion joint 6 as the bottom plate 8 and top plate 7 is also installed at the web of beam 2 to ensure the free longitudinal displacement of the expansion joint and the beam as a whole.
[0036] In this embodiment, as Figure 3 As shown, the mid-span expansion joints 6, installed on the bottom plate 8 and the top plate 7, are arranged on different elevations on both sides of the centerline of the mid-span section of the beam 2, so that the stress points of the beam joint on both sides of the fracture are in different planes, ensuring the structural performance of the beam 2 and eliminating weak points. Similarly, the mid-span expansion joints 6 installed on the web of the beam are also located on different elevations.
[0037] contrast Figure 6 and Figure 7 As shown, in this embodiment, the fixed support between the main pier 1 and the beam 2 is eliminated and a fixed connection is adopted. Since the mid-span of the beam 2 can move along the bridge direction, the main pier 1 will not generate a bending moment due to the deformation of the beam 2. Therefore, the fixed connection point 3 between the pier and the beam does not have any requirements on the height of the main pier 1, which facilitates design and construction.
[0038] contrast Figure 8 and Figure 9As shown, in the prior art, the fixed position of a long-span continuous steel beam extends and contracts to both sides from the fixed support position, and the temperature span length extends from the fixed support to the beam end. However, in this embodiment, the beam 2 can extend and contracts to both sides from the main pier 1, and because a mid-span expansion joint 6 is set in the mid-span section, its temperature span is divided into either from the main pier 1 to the beam end or from the main pier 1 to the mid-span. In this way, the length of the temperature span is greatly shortened, and its effect will be more significant for multi-span continuous beams.
[0039] This embodiment includes the following steps in its design and construction:
[0040] 1) Based on the structural stress calculation, confirm the dimensions of the first and second expansion members of the mid-span expansion device 6, and ensure that the bending and shear strength of the first and second expansion members is not less than the original structural strength, and that there are no weak points at the component locations.
[0041] 2) The beam 2 and the main pier 1 are fixed at the pier-beam fixed point 3. The steel-concrete structure can be directly poured at the same time as the pier and the beam, and then the steel-concrete joint section is constructed. The steel beam closure point is reserved. When the beam adopts a pure steel structure, the steel beam is wrapped with concrete to achieve the effect of fixed connection, and then the closure point is reserved.
[0042] 3) The first or second expansion member of the mid-span expansion device 6 is pre-embedded in the top plate 7, bottom plate 8 and web of the beam 2, and the two are locked together.
[0043] 4) Construct additional expansion joints to ultimately achieve the effect of transmitting bending moment and shear force, and being movable in the longitudinal direction of the bridge.
[0044] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.
Claims
1. A shortened temperature span structure for a steel bridge, comprising a main pier, side piers, and a beam, wherein the beam is supported on the main pier and side piers, the beam includes a mid-span section and side-span sections, and a ballastless track is provided above the beam, characterized in that: The beam body is longitudinally provided with a joint in the mid-span section so that the beam body on both sides of the mid-span section can move along the bridge direction. A mid-span expansion joint is provided at the location of the joint. When the beam body extends or contracts, the mid-span expansion joint realizes longitudinal expansion and contraction at the mid-span position. The mid-span expansion joint includes a first expansion member and a second expansion member. The first expansion member is located on the adjacent end face of the beam on both sides of the joint. Both first expansion members are provided with upper and lower bends. The second expansion member is engaged with the bends of the first expansion members on both sides.
2. The method for shortening the temperature span of a steel bridge according to claim 1, characterized in that: The mid-span expansion joint is installed on the top plate, bottom plate and web of the beam.
3. A shortened temperature span structure for steel bridges according to claim 2, characterized in that: The mid-span telescopic device located on the top plate, the mid-span telescopic device located on the bottom plate, and the mid-span telescopic device located on the web plate are arranged on different elevations on both sides of the mid-span midline.
4. A shortened temperature span structure for steel bridges according to claim 1, characterized in that: The first expansion joint and the second expansion joint are embedded in their respective beam bodies by pre-embedded parts.
5. A shortened temperature span structure for steel bridges according to claim 1, characterized in that: The beam in the mid-span section is fixed to the main pier below it.
6. A shortened temperature span structure for steel bridges according to claim 1, characterized in that: The beam of the side span is connected to the side pier below it by a longitudinally movable bearing.