Lightweight high-ductility steel-UHPC (Ultra High Performance Concrete) hollow combined tubular column

Abstract

The utility model provides a light-weight and high-ductility steel-UHPC (Ultra High Performance Concrete) hollow combined pipe column which comprises a steel pipe, an ultra high performance concrete layer, a shear-resistant stud and core micro-expansion concrete, anti-shearing studs are evenly distributed on the inner side wall of the steel pipe, the ultra-high performance concrete layer is fixedly connected with the inner side wall of the steel pipe through the anti-shearing studs, and a hollow structure is arranged in the ultra-high performance concrete layer. The upper end and the lower end of the hollow structure of the ultra-high performance concrete layer are filled with the core micro-expansion concrete, and the filling height of the single end is 1 / 6-1 / 3 of the total height of the steel pipe. According to the steel-UHPC hollow combined pipe column, light weight is achieved through the hollow section, meanwhile, the anti-seismic ductility is enhanced by filling the concrete at the end, the shear-resistant studs can ensure that the steel pipe and the UHPC layer are cooperatively stressed, and interface slippage is avoided. The utility model is suitable for scenes such as rail transit, large-span buildings and the like which need to consider both light weight and high anti-seismic property, and has the advantages of factory prefabrication, convenience in construction and the like.

Description

Technical Field

[0001] This utility model relates to the field of railway and rail transit engineering building structures and seismic technology, and in particular to a lightweight and highly ductile steel-UHPC hollow composite tube column. Background Technology

[0002] In recent years, with the rapid rise of high-speed rail and urban rail transit in my country, an increasing number of urban underground rail transit systems, railway integrated transportation hubs, and railway superstructures have emerged. These structures typically feature large spans, heavy loads, and complex structural systems, while also involving structural transitions and track-mounted columns. The cross-sectional dimensions of these track-mounted columns are strictly controlled by railway clearance limits. If the column cross-sectional dimensions are too large, it will increase the track spacing, leading to increased land use and investment, which contradicts the principle of "economical and intensive, low-carbon and green" development in my country's railway sector.

[0003] To meet structural stress and railway clearance requirements, steel-concrete composite or steel-tube concrete columns are typically used. However, these columns often have a high axial compression ratio, which leads to poor column deformation capacity and ductility. Under seismic loading, the column ends are prone to brittle crushing failure, causing structural collapse. Furthermore, existing composite columns often employ a solid cross-section design, filled with ordinary concrete. This solid design results in a large cross-section, wasting materials and contradicting the requirements for lightweight and low-carbon construction. Additionally, ordinary concrete suffers from low strength and poor toughness.

[0004] Ultra-high performance concrete (UHPC) possesses high strength, high toughness, and high durability, making it particularly suitable for long-span, heavy-load structures. Currently, UHPC has been applied in some long-span bridge structures and military engineering projects.

[0005] Based on this, a steel-UHPC composite tube column that combines lightweight and high ductility is provided to solve the problems of large cross-section, poor toughness, and low bearing capacity of traditional solid columns. This is an urgent technical problem to be solved in order to meet the application requirements of small cross-section and high ductility in high-intensity rail transit engineering. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a lightweight, highly ductile steel-UHPC hollow composite tubular column.

[0007] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: A lightweight, highly ductile steel-UHPC hollow composite tube column is provided, comprising: a steel pipe, an ultra-high performance concrete layer, shear studs, and a core micro-expansion concrete; a plurality of shear studs are evenly distributed on the inner wall of the steel pipe; the ultra-high performance concrete layer is fixedly connected to the inner wall of the steel pipe by the shear studs, and the ultra-high performance concrete layer has a hollow structure inside; the core micro-expansion concrete fills the upper and lower ends of the hollow structure within the ultra-high performance concrete layer, with a single-end filling height of 1 / 6 to 1 / 3 of the total height of the steel pipe.

[0008] This utility model provides a steel-UHPC hollow composite column, which utilizes the high strength, high toughness, and high durability of ultra-high performance concrete (UHPC). Ultra-high performance concrete is used instead of traditional ordinary concrete on the inner wall of the steel tube, improving the load-bearing capacity and toughness of the composite column. Simultaneously, based on the stress characteristics of the composite column under seismic loading, a continuous hollow structure is set in the UHPC layer within the column section. Core micro-expansion concrete is filled at the upper and lower ends of the composite column, where damage is more likely, effectively increasing the stiffness at the ends, reducing seismic damage, and significantly improving the seismic toughness of the structural column. The core micro-expansion concrete filling height at each end of the composite column is 1 / 6 to 1 / 3 of the total height of the steel tube, which can prevent column damage under seismic loading from occurring in the core joint area, satisfying the design principle of "strong joints, weak members."

[0009] Based on the above technical solution, the steel pipe has a wall thickness of ≥8mm and a cross-section that is circular or square.

[0010] Based on the above technical solution, the thickness of the ultra-high performance concrete layer is 250-350mm; the cross-section of the hollow structure inside the ultra-high performance concrete layer is circular or square, and the diameter or side length of the hollow structure is ≥500mm.

[0011] Based on the above technical solution, the length of the shear stud is 80-120mm, and the spacing between them in the transverse section of the steel pipe is 150-200mm; the spacing between them in the longitudinal section of the steel pipe is 150-200mm.

[0012] Based on the above technical solution, the ultra-high performance concrete layer is prepared from cement, silica fume, finely ground quartz sand, fine sand, metal fiber, high-efficiency water-reducing agent and water.

[0013] Based on the above technical solution, the volume percentage of the metal fiber in the ultra-high performance concrete layer is 2%-3%; the metal fiber is steel fiber, with a length of 12-20mm and an aspect ratio of 50-80.

[0014] Based on the above technical solution, the core micro-expansion concrete is made of ordinary concrete at a ratio of 35-45 kg / m³.3 It is prepared by adding an expanding agent in a certain proportion.

[0015] Based on the above technical solution, a gradual transition zone is set at the connection between the core micro-expansion concrete and the hollow structure, and the angle between the gradual transition zone and the ultra-high performance concrete layer is 30°-60°.

[0016] Furthermore, the transition zone is filled with core micro-expansion concrete. Depending on the different shapes of the steel tubes and hollow structural sections in the composite column, the hollow space inside the transition zone can be a square pyramid or a cone. The design of the transition zone serves two purposes: firstly, it smoothly transfers the load from the solid area of ​​the core micro-expansion concrete to the hollow structure, avoiding stress concentration; secondly, it prevents abrupt changes in the stiffness of the hollow column.

[0017] Based on the above technical solution, the height of the steel pipe is 5-12m; the single-end filling height of the core micro-expansion concrete is 0.8-3.5m.

[0018] Based on the above technical solution, the steel pipe, ultra-high performance concrete layer, and shear studs of the steel-UHPC hollow composite column are all processed and prefabricated in the factory and then transported to the site.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] (1) The present invention provides a lightweight and highly ductile steel-UHPC hollow composite column. By setting a continuous hollow structure in the column section of the ultra-high performance concrete layer, the stiffness and bearing capacity of the column can be significantly improved compared with the use of hollow steel pipe columns; compared with the use of solid columns, it can save materials and investment. At the same time, the use of UHPC instead of ordinary concrete in the hollow layer can achieve high strength, high toughness and durability of the composite column.

[0021] (2) This utility model provides a lightweight and highly ductile steel-UHPC hollow composite column. The hollow section serves as a predetermined energy dissipation zone, preventing damage from occurring at the column end and meeting the seismic design requirements of "strong nodes and weak components". Simultaneously, the steel-UHPC hollow layer can be prefabricated in the factory, requiring only the pouring of end concrete on-site, significantly improving construction efficiency and meeting the requirements of prefabricated buildings. The steel-UHPC hollow composite column provided by this utility model features lightweight and high ductility, eliminates the need for on-site steel reinforcement mesh, exhibits good seismic toughness and durability, and is suitable for large-span, heavy-load rail transit and railway engineering projects. Attached Figure Description

[0022] Figure 1 This is a longitudinal sectional view of the steel-UHPC hollow composite tubular column provided in Embodiments 1-3 of this utility model;

[0023] Figure 2A schematic diagram of the transverse cross section of the steel-UHPC hollow composite tube column provided in Embodiment 1 of this utility model; wherein, (a) is the upper column and the lower column; (b) is the hollow structure of the column section;

[0024] Figure 3 This is a schematic diagram of the transverse cross section of the steel-UHPC hollow composite tube column provided in Embodiment 2 of this utility model; wherein, (a) is the upper column and the lower column; (b) is the hollow structure of the column section;

[0025] Figure 4 This is a schematic diagram of the transverse cross section of the steel-UHPC hollow composite tube column provided in Embodiment 3 of this utility model; wherein, (a) is the upper column and the lower column; (b) is the hollow structure of the column section;

[0026] Figure 5 This is a longitudinal sectional view of the steel-UHPC hollow composite tube column provided in Embodiment 4 of this utility model;

[0027] Among them, 1-steel pipe; 2-ultra-high performance concrete layer; 21-upper end; 22-lower end; 3-shear stud; 4-core micro-expansion concrete; 41-gradual transition zone. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0030] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the present invention.

[0031] Example 1

[0032] like Figure 1 and Figure 2 As shown, this embodiment provides a lightweight and highly ductile steel-UHPC hollow composite tube column, including: steel tube 1, ultra-high performance concrete layer 2, shear studs 3, and core micro-expansion concrete 4;

[0033] The cross-section of steel pipe 1 is square, with a wall thickness of 40mm and a total length of 10m. Several shear studs 3 with a length of 100mm are evenly distributed on the inner wall of steel pipe 1. The spacing of the shear studs 3 along the transverse section of steel pipe 1 is 200mm, and the spacing along the longitudinal section of steel pipe 1 is 200mm.

[0034] The ultra-high performance concrete layer 2 has a square cross-section and a thickness of 300 mm, and is fixedly connected to the steel pipe 1 by shear studs 3. The ultra-high performance concrete layer 2 has a hollow internal structure; the hollow structure has a square cross-section with a side length of 1200 mm. The core micro-expansion concrete 4 fills the upper end 21 and lower end 22 of the ultra-high performance concrete layer 2, with a single-end filling height of 2.5 m.

[0035] Furthermore, in this embodiment, the ultra-high performance concrete layer 2 is prepared from cement, silica fume, finely ground silica sand, fine sand, metal fibers, high-efficiency water-reducing agent, and water. The metal fibers are 12-20 mm in length and have an aspect ratio of 50-80, with steel fibers comprising 2.5% of the volume in the ultra-high performance concrete layer 2. The core micro-expansion concrete 4 is ordinary concrete mixed with water at a concentration of 35 kg / m³. 3 It is made by adding an expanding agent in a certain proportion.

[0036] The steel-UHPC hollow composite column provided in this embodiment significantly improves the stiffness and load-bearing capacity of the column compared to using hollow steel pipe columns, by setting a continuous hollow structure in the column section of the ultra-high performance concrete layer 2. Compared to using solid steel columns, it saves materials and investment. Furthermore, using UHPC instead of ordinary concrete in the hollow layer achieves high strength, high toughness, and durability in the composite column. In addition, the shear stud design ensures better synergistic stress distribution between the steel pipe and UHPC, limiting slippage and improving overall seismic energy dissipation capacity. The metal fibers added to the ultra-high performance concrete layer 2 form a fiber bridging effect at cracks, controlling crack width, delaying stiffness degradation, and increasing the equivalent damping ratio.

[0037] Example 2

[0038] This embodiment provides a lightweight and highly ductile steel-UHPC hollow composite tube column, comprising: a steel tube 1, an ultra-high performance concrete layer 2, shear studs 3, and a core micro-expansion concrete 4;

[0039] like Figure 3 As shown, the cross-section of steel pipe 1 is circular, its wall thickness is 30mm, and its total length is 8m. Several shear studs 3 with a length of 80mm are evenly distributed on the inner wall of steel pipe 1. The spacing of the shear studs 3 along the circumference of steel pipe 1 is 150mm, and the spacing along the longitudinal direction of steel pipe 1 is 150mm.

[0040] The ultra-high performance concrete layer 2 has a circular cross-section and a thickness of 250 mm, and is fixedly connected to the steel pipe 1 by shear studs 3. The interior of the ultra-high performance concrete layer 2 has a hollow structure; the cross-section of the hollow structure is circular with a diameter of 800 mm. The core micro-expansion concrete 4 fills the upper end 21 and lower end 22 of the ultra-high performance concrete layer 2, with a single-end filling height of 2 m.

[0041] Furthermore, in this embodiment, the ultra-high performance concrete layer 2 is prepared from cement, silica fume, finely ground silica sand, fine sand, metal fibers, high-efficiency water-reducing agent, and water. The metal fibers are steel fibers with a length of 12-20 mm and an aspect ratio of 50-80, and the volume percentage of the steel fibers in the ultra-high performance concrete layer 2 is 2%. The core micro-expansion concrete 4 is ordinary concrete mixed with water at a concentration of 40 kg / m³. 3 It is made by adding an expanding agent in a certain proportion.

[0042] Example 3

[0043] This embodiment provides a lightweight and highly ductile steel-UHPC hollow composite tube column, comprising: a steel tube 1, an ultra-high performance concrete layer 2, shear studs 3, and a core micro-expansion concrete 4;

[0044] like Figure 4 As shown, the cross-section of steel pipe 1 is square, with a wall thickness of 50mm and a total length of 12m. Several shear studs 3 with a length of 120mm are evenly distributed on the inner wall of steel pipe 1. The spacing of the shear studs 3 along the transverse section of steel pipe 1 is 180mm, and the spacing along the longitudinal section of steel pipe 1 is 180mm.

[0045] The ultra-high performance concrete layer 2 has a cross-section that is square on the outside and circular on the inside, with a thickness of 250-350 mm, and is fixedly connected to the steel pipe 1 by shear studs 3. The interior of the ultra-high performance concrete layer 2 has a hollow structure; the cross-section of the hollow structure is circular with a diameter of 1000 mm. The core micro-expansion concrete 4 fills the upper end 21 and lower end 22 of the ultra-high performance concrete layer 2, with a single-end filling height of 3 m.

[0046] Furthermore, in this embodiment, the ultra-high performance concrete layer 2 is prepared from cement, silica fume, finely ground silica sand, fine sand, metal fibers, high-efficiency water-reducing agent, and water. The metal fibers are 12-20 mm in length and have an aspect ratio of 50-80, with steel fibers comprising 3% of the volume in the ultra-high performance concrete layer 2; the core micro-expansion concrete 4 is ordinary concrete mixed with water at a concentration of 45 kg / m³. 3 It is made by adding an expanding agent in a certain proportion.

[0047] Example 4

[0048] like Figure 5 As shown, this embodiment provides a lightweight, highly ductile steel-UHPC hollow composite column. The difference from Embodiment 1 is that a gradual transition zone 41 is added at the connection between the core micro-expansion concrete 4 filling the upper end 21 and lower end 22 and the hollow structure of the column body. The gradual transition zone 41 has a height of 0.8m, is filled with the core micro-expansion concrete 4, and its inner hollow space is a quadrangular pyramid shape.

[0049] In this embodiment, by setting a gradual transition zone 41 at the connection between the core micro-expansion concrete 4 and the hollow structure, the key problems such as stress concentration and sudden stiffness change are comprehensively solved through geometric transition design. It is especially suitable for high-rise buildings or bridge piers and other scenarios with high requirements for ductility and energy consumption.

[0050] Example 5

[0051] This embodiment provides a construction method for the steel-UHPC hollow composite tubular column in Embodiments 1-4, including the following steps:

[0052] Step 1: Process steel pipe 1, ultra-high performance concrete layer 2, and shear studs 3 in the factory;

[0053] Step 2: Set an ultra-high performance concrete layer 2 on the inner wall of the steel pipe 1, and use shear studs 3 to connect and fix the ultra-high performance concrete layer 2 to the steel pipe 1 to improve the connection strength and integrity of the two.

[0054] Step 3: Transport the prefabricated steel-UHPC hollow structure to the site. According to the design structural dimensions, fill the upper end 21 and lower end 22 of the ultra-high performance concrete layer 2 with micro-expansion concrete 4 to improve the stiffness and load-bearing capacity of the column.

[0055] Step 4: Cure the micro-expansion concrete 4 filling the upper end 21 and lower end 22 to the design strength, thus completing the construction of the steel-UHPC hollow composite column.

[0056] The construction method for steel-UHPC hollow composite columns provided in this embodiment utilizes factory prefabrication of the steel-UHPC hollow structure. On-site pouring of micro-expansion concrete at the ends is required, significantly improving construction efficiency. This aligns with the national promotion of efficient and green design and construction concepts for prefabricated structures, meeting energy-saving and environmental protection requirements. The steel-UHPC hollow composite columns produced in this embodiment are lightweight and highly ductile, eliminating the need for on-site reinforcement mesh, resulting in stronger overall structural integrity and stable quality. They are suitable for high-seismic-intensity rail transit projects, meeting the seismic design requirements of "strong nodes and weak components."

[0057] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the content of the present utility model specification should be included within the protection scope of the present utility model.

Claims

1. A lightweight, high-ductility steel-UHPC hollow composite tubular column, characterized in that, include: Steel pipe (1), ultra-high performance concrete layer (2), shear studs (3) and core micro-expansion concrete (4); The inner wall of the steel pipe (1) is evenly distributed with a number of shear studs (3); The ultra-high performance concrete layer (2) is fixedly connected to the inner wall of the steel pipe (1) by shear studs (3), and the ultra-high performance concrete layer (2) has a hollow structure inside; The core micro-expansion concrete (4) fills the upper end (21) and lower end (22) of the hollow structure inside the ultra-high performance concrete layer (2), with the filling height at one end being 1 / 6 to 1 / 3 of the total height of the steel pipe (1).

2. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The steel pipe (1) has a wall thickness of ≥8mm and a cross-section that is circular or square.

3. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The thickness of the ultra-high performance concrete layer (2) is 250-350mm; the cross-section of the hollow structure inside the ultra-high performance concrete layer (2) is circular or square, and the diameter or side length of the hollow structure is ≥500mm.

4. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The length of the shear studs (3) is 80-120mm, the spacing between them in the transverse section of the steel pipe (1) is 150-200mm, and the spacing between them in the longitudinal section of the steel pipe (1) is 150-200mm.

5. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The ultra-high performance concrete layer (2) is made of cement, silica fume, finely ground quartz sand, fine sand, metal fiber, high-efficiency water-reducing agent and water.

6. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 5, characterized in that, The volume percentage of the metal fiber in the ultra-high performance concrete layer (2) is 2%-3%; the metal fiber is steel fiber with a length of 12-20mm and an aspect ratio of 50-80.

7. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The core micro-expansion concrete (4) is made of ordinary concrete at a ratio of 35-45 kg / m³. 3 It is prepared by adding an expanding agent in a certain proportion.

8. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, A gradual transition zone (41) is provided at the connection between the core micro-expansion concrete (4) and the hollow structure. The angle between the gradual transition zone (41) and the ultra-high performance concrete layer (2) is 30°-60°.

9. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The height of the steel pipe (1) is 5-12m; the single-end filling height of the core micro-expansion concrete (4) is 0.8-3.5m.

10. The lightweight, high-ductility steel-UHPC hollow composite tubular column according to claim 1, characterized in that, The steel pipe (1), ultra-high performance concrete layer (2), and shear studs (3) of the steel-UHPC hollow composite column are all processed and prefabricated in the factory and then transported to the site.

Images