A pressure-bearing steel-UHPC-NC hybrid beam structure

Abstract

This invention discloses a pressure-bearing steel-UHPC-NC hybrid beam structure, including steel beams and NC beams, as well as UHPC beams. The first end of the UHPC beam connects to the steel beam and has the same thickness as the steel beam, while the second end of the UHPC beam connects to the NC beam and has the same thickness as the NC beam. The thickness of the UHPC beam gradually increases from the first end to the second end. This invention utilizes the excellent compressive strength and crack resistance of ultra-high performance concrete, employing a pure UHPC beam as the transition section between the steel beam and the NC beam, simplifying the construction of the steel-concrete connection section. The structure exhibits superior load-bearing performance and is easy to construct. By utilizing the gradual change in the thickness of the UHPC beam wall panels, the main beam gradually transitions from the thinner-walled steel beam to the thicker-walled NC beam, resulting in a smooth transition in main beam stiffness and avoiding large deformation angles, thus improving driving comfort. The invention eliminates the need for conventional steel beam stiffening transition sections and concrete beam reinforcement transition sections, saving steel and concrete usage, reducing the workload of steel structure processing and concrete pouring, and saving costs.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and in particular to a pressure-bearing steel-UHPC-NC hybrid beam structure. Background Technology

[0002] A hybrid beam is a type of main beam formed by combining steel beams and NC (Normal Concrete) beams along the length of a bridge. Hybrid beams make good use of the advantages of both steel and concrete, improve the stress performance of the structural system, have good engineering economy, and are widely used in long-span cable-stayed bridges.

[0003] Hybrid beams generally consist of three parts: a steel beam stiffening transition section, a steel-concrete composite section, and a non-concrete (NC) beam reinforced transition section. The steel-concrete composite section is the transition section between the steel beam and the NC beam, and it is also the junction of the two different materials. Currently, the conventional steel-concrete composite section is formed by inserting steel plates into the NC beam to create steel gratings, and then arranging shear connectors and transverse reinforcing bars on the steel gratings. This joint structure is complex, the internal space of the gratings is small, the on-site construction workload is large, and the quality of concrete pouring is difficult to guarantee.

[0004] Furthermore, due to the large variation in the cross-sectional dimensions of the main beams on both sides of the hybrid beam, it is necessary to set up steel beam stiffening transition sections and NC beams for reinforcement to facilitate the transition. The workload of steel beam processing and concrete pouring is large, and the change in the stiffness of the main beams is prone to deformation and bending, resulting in uneven driving. Cracks have appeared in the concrete transition sections of some existing bridges, which seriously affects the safety and durability of the hybrid beam. Summary of the Invention

[0005] This invention provides a pressure-bearing steel-UHPC-NC hybrid beam structure to solve the technical problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention proposes a pressure-bearing steel-UHPC-NC hybrid beam structure, including a steel beam and an NC beam, and also including a UHPC beam. The first end of the UHPC beam is connected to the steel beam and has the same thickness as the steel beam. The second end of the UHPC beam is connected to the NC beam and has the same thickness as the NC beam. The thickness of the UHPC beam gradually increases from the first end to the second end.

[0007] Furthermore, a flat steel plate is provided on one end of the steel beam that connects to the UHPC beam, and a shear connector is provided on the flat steel plate, the shear connector being embedded in the UHPC beam.

[0008] Furthermore, the UHPC beam is integrally cast from UHPC with a compressive strength of over 100MPa and an axial tensile strength of over 7MPa, and the UHPC beam has no steel plates or corresponding shear connectors on its surrounding surface and inside.

[0009] Furthermore, the UHPC beam includes a UHPC beam top plate, a UHPC beam bottom plate, and a UHPC beam web, which together form a box-shaped structure.

[0010] Furthermore, the steel beam includes a top plate, a bottom plate, and a web, which together form a box-shaped structure.

[0011] Furthermore, the top plate of the steel beam is provided with a steel beam top plate stiffening rib, the bottom plate of the steel beam is provided with a steel beam bottom plate stiffening rib, and the web plate of the steel beam is provided with a steel beam web plate stiffening rib. The cross-section of the steel beam top plate stiffening rib, the steel beam bottom plate stiffening rib, and the steel beam web plate stiffening rib is an inverted T-shape.

[0012] Furthermore, the steel beam is provided with a steel beam diaphragm, the upper and lower ends of which are connected to the top plate and bottom plate of the steel beam, respectively, and the steel beam diaphragm is provided with steel beam diaphragm stiffening ribs.

[0013] Furthermore, the NC beam includes an NC beam top plate, an NC beam bottom plate, an NC beam web, and an NC beam diaphragm. The NC beam top plate, NC beam bottom plate, and NC beam web together form a box-shaped structure, and the upper and lower ends of the NC beam diaphragm are respectively connected to the NC beam top plate and the NC beam bottom plate.

[0014] Furthermore, longitudinal reinforcement bars are arranged inside the NC beam, and the longitudinal reinforcement bars extend and are anchored inside the UHPC beam.

[0015] Furthermore, it also includes prestressing tendons, one end of which is anchored inside the NC beam, and the other end of which passes longitudinally through the UHPC beam and is then anchored to the steel beam.

[0016] The present invention has the following beneficial effects:

[0017] 1. The pressure-bearing steel-UHPC-NC hybrid beam structure of the present invention utilizes the excellent compressive strength and crack resistance of ultra-high performance concrete, and uses pure UHPC beams as the transition section between steel beams and NC beams, which simplifies the construction of the steel-concrete connection section, resulting in superior structural performance and easy construction.

[0018] 2. This invention utilizes the gradual change in the thickness of the UHPC beam wall panel to gradually transition the main beam from a steel beam with a thinner wall panel to an NC beam with a thicker wall panel. The transition in the stiffness of the main beam is smooth, which can avoid large deformation angles, prevent bumps when the vehicle is driving, and improve driving comfort.

[0019] 3. This invention eliminates the conventional steel beam stiffening transition section and concrete beam reinforcement transition section, saving steel and concrete usage, reducing the workload of steel structure processing and concrete pouring, and saving costs.

[0020] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 This is a schematic diagram of the longitudinal section AA of a pressure-bearing steel-UHPC-NC hybrid beam structure according to the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the standard cross-section of the steel beam at point BB;

[0024] Figure 3 yes Figure 1 Schematic diagram of the end cross section of the steel beam at point CC;

[0025] Figure 4 yes Figure 1 Schematic diagram of the cross section of the UHPC beam at point DD;

[0026] Figure 5 yes Figure 1 Schematic diagram of cross-section of UHPC beam and NC beam at the EE section;

[0027] Figure 6 This is a detailed schematic diagram of the top plate and stiffening ribs of the steel beam.

[0028] The labels in the diagram represent:

[0029] 1. Steel beam; 11. Top plate of steel beam; 12. Bottom plate of steel beam; 13. Web of steel beam; 14. Diaphragm of steel beam; 15. Stiffening rib of top plate of steel beam; 16. Stiffening rib of bottom plate of steel beam; 17. Stiffening rib of web of steel beam; 18. Stiffening rib of diaphragm of steel beam; 19. Flat steel plate; 2. UHPC beam; 20. Shear connector; 21. Top plate of UHPC beam; 22. Bottom plate of UHPC beam; 23. Web of UHPC beam; 3. NC beam; 31. Top plate of NC beam; 32. Bottom plate of NC beam; 33. Web of NC beam; 34. Diaphragm of NC beam; 35. Prestressed tendon. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0031] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0032] It should also be noted that, unless otherwise explicitly specified and limited, the terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also refer to the internal connection of two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0033] like Figure 1 and Figure 2 As shown, the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment includes a steel beam 1 and an NC beam 3, and also includes a UHPC beam 2. The first end of the UHPC beam 2 is connected to the steel beam 1 and has the same thickness as the steel beam 1. The second end of the UHPC beam 2 is connected to the NC beam 3 and has the same thickness as the NC beam 3. The thickness of the UHPC beam 2 gradually increases from the first end to the second end.

[0034] in, Figure 2 The cross-section of the hybrid beam structure is shown. Figure 1The longitudinal section of the hybrid beam structure is shown. Utilizing the excellent compressive strength and crack resistance of UHPC (Ultra High Performance Concrete), a pure UHPC beam 2 is used as the transition section connecting steel beam 1 and NC beam 3, simplifying the construction of the steel-concrete connection section. This results in superior stress performance and convenient construction of the hybrid beam structure. By utilizing the gradual change in wall thickness of UHPC beam 2, the main beam gradually transitions from the thinner-walled steel beam 1 to the thicker-walled NC beam 3. The transition in main beam stiffness is smooth, avoiding large deformation angles and preventing bumps during vehicle travel, thus improving driving comfort. The conventional steel beam stiffening transition section and concrete beam reinforcement transition section are eliminated, saving steel and concrete usage, reducing the workload of steel structure processing and concrete pouring, and saving costs.

[0035] In the bearing-type steel-UHPC-NC hybrid beam structure of this embodiment, a flat steel plate 19 is provided on one end of the steel beam 1 and the UHPC beam 2. A shear connector 20 is provided on the flat steel plate 19 and embedded in the UHPC beam 2. The flat steel plate 19 is welded to the steel beam 1, and the shear connector 20 is welded to the flat steel plate 19. The shear connector 20 is embedded in the UHPC beam 2 to connect the UHPC beam 2 and the steel beam 1. The huge internal force on the side of the steel beam 1 is transferred to the UHPC beam 2 by the flat steel plate 19 and then gradually transferred to the NC beam 3. The hybrid beam does not need to set up a conventional and complicated steel-concrete joint section structure. The steel-concrete joint section structure is greatly simplified, the force transmission efficiency is high, and the construction is simple.

[0036] In the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment, the UHPC beam 2 is integrally cast from UHPC with a compressive strength of over 100MPa and an axial tensile strength of over 7MPa. The UHPC beam 2 has no steel plates or corresponding shear connectors on its surrounding surface and inside. The UHPC beam 2, which is integrally cast from UHPC with a compressive strength of over 100MPa and an axial tensile strength of over 7MPa, has excellent compressive strength and crack resistance. Furthermore, the absence of steel plates and corresponding shear connectors on its surrounding surface and inside makes the UHPC beam 2 structure simple and easy to construct.

[0037] like Figure 4 As shown, in the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment, the UHPC beam 2 includes a UHPC beam top plate 21, a UHPC beam bottom plate 22, and a UHPC beam web 23. The UHPC beam top plate 21, UHPC beam bottom plate 22, and UHPC beam web 23 together form a box-shaped structure. The road surface is above the UHPC beam top plate 21, the UHPC beam bottom plate 22 is located on the bridge pier, and the UHPC beam web 23 is used to connect the UHPC beam top plate 21 and the UHPC beam bottom plate 22.

[0038] like Figure 2and Figure 3 As shown, in the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment, the steel beam 1 includes a steel beam top plate 11, a steel beam bottom plate 12, and a steel beam web plate 13. The steel beam top plate 11, steel beam bottom plate 12, and steel beam web plate 13 together form a box-shaped structure. The steel beam top plate 11, steel beam bottom plate 12, and steel beam web plate 13 are respectively connected to the UHPC beam top plate 21, UHPC beam bottom plate 22, and UHPC beam web plate 23 through a flat steel plate 19 and a shear connector 20.

[0039] like Figure 6 As shown, in the bearing-type steel-UHPC-NC hybrid beam structure of this embodiment, the top plate 11 of the steel beam is provided with a steel beam top plate stiffener 15, the bottom plate 12 of the steel beam is provided with a steel beam bottom plate stiffener 16, and the web plate 13 of the steel beam is provided with a steel beam web stiffener 17. The cross-section of the steel beam top plate stiffener 15, the steel beam bottom plate stiffener 16, and the steel beam web stiffener 17 is inverted T-shaped. At the same time, the height of the inverted T-shaped steel beam top plate stiffener 15, the steel beam bottom plate stiffener 16, and the steel beam web stiffener 17 remains unchanged along the longitudinal direction. The steel beam top plate stiffener 15, the steel beam bottom plate stiffener 16, and the steel beam web stiffener 17 are used to strengthen the strength of the steel beam 1.

[0040] In the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment, the steel beam 1 is provided with a steel beam diaphragm 14. The upper and lower ends of the steel beam diaphragm 14 are respectively connected to the top plate 11 and the bottom plate 12 of the steel beam. The steel beam diaphragm 14 is provided with steel beam diaphragm stiffening ribs 18. The steel beam diaphragm 14 is arranged along the longitudinal direction of the hybrid beam to strengthen the strength of the steel beam 1.

[0041] like Figure 5 As shown, in the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment, the NC beam 3 includes an NC beam top plate 31, an NC beam bottom plate 32, an NC beam web 33, and an NC beam diaphragm 34. The NC beam top plate 31, NC beam bottom plate 32, and NC beam web 33 together form a box-shaped mechanism. The upper and lower ends of the NC beam diaphragm 34 are respectively connected to the NC beam top plate 31 and the NC beam bottom plate 32. The NC beam top plate 31, NC beam bottom plate 32, and NC beam web 33 are respectively connected to the UHPC beam top plate 21, UHPC beam bottom plate 22, and UHPC beam web 23. The NC beam diaphragm 34 is arranged along the longitudinal direction of the hybrid beam to strengthen the strength of the NC beam 3.

[0042] In the pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment, longitudinal steel bars are also arranged inside the NC beam 3. The longitudinal steel bars extend and are anchored inside the UHPC beam 2. The longitudinal steel bars are used to strengthen the strength of the NC beam 3 and connect the NC beam 3 and the UHPC beam 2.

[0043] like Figure 3-5As shown, in the bearing-type steel-UHPC-NC hybrid beam structure of this embodiment, prestressed tendons 35 are arranged inside the NC beam 3. One end of the prestressed tendon 35 is anchored inside the NC beam 3, and the other end passes longitudinally through the UHPC beam 2 and is anchored to the steel beam 1. The prestressed tendon 35 can strengthen the strength of the UHPC beam 2 and the NC beam 3, and make the connection between the steel beam 1, the UHPC beam 2 and the NC beam 3 more stable.

[0044] The pressure-bearing steel-UHPC-NC hybrid beam structure of this embodiment includes a steel beam segment 1, a UHPC beam segment 2, and an NC beam segment 3 arranged sequentially. Each segment of the hybrid beam is a box-shaped structure with a consistent external shape. A flat steel plate 19 is set at the end of the steel beam 1, and a shear connector 20 is set on the flat steel plate 19. One end of the UHPC beam 2 is closely attached to the flat steel plate 19 and connected to the steel beam 1 through the shear connector 20. The other end of the UHPC beam is connected to the NC beam 3. The steel-concrete composite section transitions from the thin-walled steel beam 1 to the thick-walled concrete slab through a gradual change in the wall thickness of the UHPC beam 2. Prestressed tendons are set in the UHPC beam 2, with one end anchored in the NC beam 3 and the other end anchored to the flat steel plate 19 at the end of the steel beam 1. This invention fully utilizes the advantages of UHPC's strong compressive strength and high crack resistance to optimize the conventional complex steel-concrete composite section structure, and has the advantages of simple structure, superior stress performance, smooth stiffness transition, and convenient construction.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pressure-bearing steel-UHPC-NC hybrid beam structure, comprising a steel beam (1) and an NC beam (3), characterized in that, It also includes a UHPC beam (2), the first end of which is connected to the steel beam (1) and has the same thickness as the steel beam (1), the second end of which is connected to the NC beam (3) and has the same thickness as the NC beam (3), and the thickness of the UHPC beam (2) gradually increases from the first end to the second end; A flat steel plate (19) is provided on one end of the steel beam (1) that connects to the UHPC beam (2). A shear connector (20) is provided on the flat steel plate (19), and the shear connector (20) is embedded in the UHPC beam (2). The UHPC beam (2) is integrally cast from UHPC with a compressive strength of over 100MPa and an axial tensile strength of over 7MPa. The UHPC beam (2) has no steel plates or corresponding shear connectors on its four sides and inside. The pressure-bearing steel-UHPC-NC hybrid beam structure also includes prestressed tendons (35), one end of which is anchored inside the NC beam (3), and the other end passes longitudinally through the UHPC beam (2) and is then anchored on the steel beam (1); The pressure-bearing steel-UHPC-NC hybrid beam structure includes a steel beam (1), a UHPC beam (2) and an NC beam (3) arranged in sequence. Each beam segment of the hybrid beam is a box-shaped structure with a consistent shape.

2. The pressure-bearing steel-UHPC-NC hybrid beam structure according to claim 1, characterized in that, The UHPC beam (2) includes a UHPC beam top plate (21), a UHPC beam bottom plate (22) and a UHPC beam web plate (23), which together form a box-shaped structure.

3. The pressure-bearing steel-UHPC-NC hybrid beam structure according to claim 1, characterized in that, The steel beam (1) includes a top plate (11), a bottom plate (12), and a web (13), which together form a box-shaped structure.

4. The pressure-bearing steel-UHPC-NC hybrid beam structure according to claim 3, characterized in that, The top plate (11) of the steel beam is provided with a steel beam top plate stiffening rib (15), the bottom plate (12) of the steel beam is provided with a steel beam bottom plate stiffening rib (16), and the web plate (13) of the steel beam is provided with a steel beam web plate stiffening rib (17). The cross-section of the steel beam top plate stiffening rib (15), the steel beam bottom plate stiffening rib (16) and the steel beam web plate stiffening rib (17) is an inverted T-shape.

5. A pressure-bearing steel-UHPC-NC hybrid beam structure according to claim 3, characterized in that, The steel beam (1) is provided with a steel beam diaphragm (14), the upper and lower ends of the steel beam diaphragm (14) are respectively connected to the top plate (11) and the bottom plate (12) of the steel beam, and the steel beam diaphragm (14) is provided with steel beam diaphragm stiffening ribs (18).

6. The pressure-bearing steel-UHPC-NC hybrid beam structure according to claim 1, characterized in that, The NC beam (3) includes an NC beam top plate (31), an NC beam bottom plate (32), an NC beam web plate (33), and an NC beam diaphragm plate (34). The NC beam top plate (31), NC beam bottom plate (32), and NC beam web plate (33) together form a box-shaped structure. The upper and lower ends of the NC beam diaphragm plate (34) are respectively connected to the NC beam top plate (31) and the NC beam bottom plate (32).

7. A pressure-bearing steel-UHPC-NC hybrid beam structure according to claim 1, characterized in that, Longitudinal reinforcement bars are arranged inside the NC beam (3), and the longitudinal reinforcement bars extend and are anchored inside the UHPC beam (2).

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