A tapered inner diameter steel pipe concrete column

Abstract

The utility model discloses a kind of gradually changing inner diameter steel pipe concrete columns, including gradually changing inner diameter arc steel pipe, the gradually changing inner diameter arc steel pipe is equipped with through bolt, the wall surface of gradually changing inner diameter arc steel pipe is equipped with several protruding particles;The gradually changing inner diameter arc steel pipe inside and outside respectively has core concrete and external concrete and pours.Gradually changing inner diameter arc steel pipe Midsection pipe wall thickness is less than two end pipe wall thickness.Arc inner wall steel pipe restricts concrete transverse expansion by its rigidity, generates annular restraint force, also has the role of tamping core concrete density, improves concrete strength.No need to set reinforcing steel etc. in steel pipe interior It can improve the adhesion of concrete and steel pipe inner wall.Granule protrusion exists to make steel pipe inner wall surface roughness improve, uneven surface and core concrete mutually embed, occlusion, increase the resistance between steel pipe and concrete sliding.Granule existence increases the actual contact area of steel pipe inner wall and concrete.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering structural technology, specifically to a steel tube concrete column with gradually changing inner diameter. Background Technology

[0002] With the widespread application of concrete-filled steel tubular (CFST) columns in industrial and civil buildings, bridges, and towers, engineering practice and research have shown that CFST is not only a high-strength, high-performance structure but also an efficient construction technology. The requirements for tall and heavy-load engineering structures are gradually increasing, demanding that components possess both high load-bearing capacity and good ductility. However, in existing CFST columns, the bond strength between the concrete and the inner wall of the steel tubing decreases significantly before reaching the ultimate load-bearing capacity, potentially causing failure before this threshold is reached. Traditional steel tubing has a smooth surface, and the bond between the steel tubing and the core concrete relies primarily on surface friction between the tubing wall and the concrete.

[0003] For bridge piers, under the combined action of vertical and horizontal loads, the bending moment is large at the ends, such as the top and bottom, while the shear force is also significant at the ends. According to structural mechanics principles, the normal stress generated by the bending moment and the shear stress generated by the shear force are superimposed at the ends, making the stress state at the ends more complex and the shear stress level relatively high. This easily reaches the shear strength limit of the concrete, thus inducing shear failure. Traditional reinforced concrete bridge piers, due to insufficient bending and shear capacity, are more prone to shear failure at the ends, leading to beam collapse and bridge collapse. It is necessary to improve the bending and shear capacity of the components and enhance their seismic resistance. Increasing the density of stirrups is a measure to improve the ductility and shear strength of bridge piers. However, excessive stirrups not only cause many inconveniences in construction and reduce the quality of concrete pouring, but also worsen the bond between concrete and stirrups as the amount of stirrups in the pier increases, weakening the overall performance and reducing the ductility and deformation capacity of the bridge pier.

[0004] Conventional steel-concrete composite columns have steel pipes on the outside, which will corrode and rust over time. In the event of a fire, the advantages of traditional steel-concrete composite members gradually weaken. Once the outer steel pipe fails, the residual load-bearing capacity provided by the concrete inside the pipe is difficult to meet the requirements of large-span, tall, and heavy-load engineering structures.

[0005] The presence of through bolts significantly improves the integrity, stiffness, and strength of concrete column structures. Exposed nuts, due to their lack of waterproofing, are more likely to corrode the structural core. Utility Model Content

[0006] The purpose of this invention is to provide a steel tube concrete column with a gradually changing inner diameter, so as to increase the load-bearing capacity of the concrete column and improve its deformation capacity.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a gradually changing inner diameter steel tube concrete column, comprising a gradually changing inner diameter arc-shaped steel tube, wherein the gradually changing inner diameter arc-shaped steel tube is provided with through bolts, and the wall surface of the gradually changing inner diameter arc-shaped steel tube is provided with a plurality of protruding particles. The gradually changing inner diameter arc-shaped steel pipe is filled with core concrete and outer concrete, respectively.

[0008] Preferably, the wall thickness of the middle section of the gradually changing inner diameter arc-shaped steel pipe is less than the wall thickness of both ends.

[0009] Preferably, a plurality of the through bolts form a through bolt group, and the through bolt group has a plurality of bolts; the plurality of through bolts in the through bolt group are arranged in an alternating manner.

[0010] Preferably, the angle range of the staggered arrangement of the through bolts in the through bolt group is 0-180°.

[0011] Preferably, the protruding particles include protruding particles on the inner wall of the steel pipe and protruding particles on the outer wall of the steel pipe, and the protruding particles on the inner wall of the steel pipe and the protruding particles on the outer wall of the steel pipe are respectively disposed on the inner wall and the outer wall of the arc-shaped steel pipe with a gradually changing inner diameter.

[0012] Preferably, the two ends of the through bolt are fixed by nuts, and the nuts are tightly attached to the outer wall of the arc-shaped steel pipe with a gradually changing inner diameter.

[0013] Preferably, the side wall of the gradually changing inner diameter arc-shaped steel pipe is provided with bolt holes, and the through bolt passes through the bolt holes.

[0014] Preferably, both the inner and outer wall protrusions of the steel pipe are hemispherical.

[0015] Preferably, the protrusions on the inner and outer walls of the steel pipe are arranged circumferentially, and the positions of the protrusions on the inner and outer walls of the steel pipe are corresponding inside and outside on the gradually changing inner diameter arc-shaped steel pipe.

[0016] Preferably, the gap between the bolt hole and the through bolt is filled with concrete.

[0017] Compared with the prior art, the beneficial effects of this utility model are: 1. The advantage of using an arc-shaped inner wall structure for the steel pipe is that after the core concrete is formed inside the steel pipe, it is constrained by the arc-shaped inner wall structure in the middle section of the pipe. This arc-shaped structure strengthens the triaxial constraint force on the concrete. The arc-shaped inner wall of the steel pipe restricts the lateral expansion of the concrete through its own stiffness, generating circumferential constraint force. It also helps to compact the core concrete, increasing its strength. This improves the bond between the concrete and the inner wall of the steel pipe without the need for additional reinforcement inside the pipe.

[0018] 2. The advantages of having micro-protruding particles on both the inner and outer walls of the steel pipe are as follows: The presence of these particles increases the surface roughness of the inner wall of the steel pipe. The uneven surface interlocks and meshes with the core concrete, increasing the resistance to sliding between the steel pipe and the concrete. The presence of particles increases the actual contact area between the inner wall of the steel pipe and the concrete. This increased contact area increases the friction between the inner wall of the steel pipe and the core concrete. The particles on the inner wall make the confinement of the concrete within the steel pipe more effective.

[0019] 3. The stress state at the ends of concrete columns is complex, with relatively high shear stress levels, making it easy to reach the shear strength limit of the concrete and thus trigger shear failure. Adding through bolts to the upper and lower sections of the steel pipe offers the advantage of: increasing prestress in the concrete column, effectively preventing shear failure at the column ends; and, as a powerful fixing tool, bolts can combine the overall properties of the concrete and steel pipe, thereby maintaining the overall structural safety of the building.

[0020] 4. The advantages of internally cast core concrete are: After thorough and uniform vibration, the core concrete can interact tightly with the arc-shaped structure and raised particles of the steel tube's inner wall. The prestress provided by the through bolts at the column ends further strengthens the bond between the steel tube and the internal core concrete. The interaction between the through bolts, concrete, and steel tube forms an inseparable whole, improving the strength and stability of the concrete-filled steel tube column.

[0021] 5. The advantages of externally cast concrete around steel pipes are: Since the steel pipes and bolts are exposed, the external concrete can completely encase the exposed bolt structure, preventing corrosion and extending their service life. It also improves the durability of the concrete and maintains the synergistic working relationship between the steel pipe and the concrete. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the gradually changing inner diameter steel tube concrete column of this utility model.

[0023] Figure 2 This is a cross-sectional view of another embodiment of the gradually changing inner diameter steel tube concrete column of this utility model.

[0024] Figure 3 This is a top view of the gradually changing inner diameter steel tube concrete column of this utility model.

[0025] Figure 4 This is a top cross-sectional view of another embodiment of the gradually changing inner diameter steel tube concrete column of this utility model.

[0026] 1. Variable inner diameter arc-shaped steel pipe; 2. Protrusions on the inner wall of the steel pipe; 3. Protrusions on the outer wall of the steel pipe; 4. Through bolts; 5. Core concrete; 6. External concrete. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. 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.

[0028] Please see Figure 1-4 This utility model provides a technical solution: a gradually changing inner diameter steel tube concrete column, including a gradually changing inner diameter arc-shaped steel tube 1, the gradually changing inner diameter arc-shaped steel tube 1 is provided with through bolts 4, and the wall surface of the gradually changing inner diameter arc-shaped steel tube 1 is provided with several protruding particles.

[0029] The wall thickness of the middle section of the gradually changing inner diameter arc-shaped steel pipe 1 is less than that of the two ends, so that the gradually changing inner diameter arc-shaped steel pipe 1 of this structure presents different diameters on the inner wall of different cross sections.

[0030] like Figure 1-2 As shown, several through bolts 4 form through bolt groups, and there are several through bolt groups. The through bolt groups can be arranged only at the upper end of the gradually changing inner diameter arc-shaped steel pipe 1, or only at the lower end; they can be arranged simultaneously at the upper and lower ends, or evenly from top to bottom. Figure 3-4 As shown, the through bolts 4 in the through bolt group are staggered, with an angle range of 0-180°.

[0031] The two ends of the through bolt 4 are fixed by nuts, and the nuts are tightly attached to the outer wall of the arc-shaped steel pipe 1 with a gradually changing inner diameter. Bolt holes are opened on the side wall of the arc-shaped steel pipe 1 with a gradually changing inner diameter, and the through bolt 4 passes through the bolt holes.

[0032] The protruding particles include inner wall protrusions 2 and outer wall protrusions 3, which are respectively disposed on the inner and outer walls of the gradually changing inner diameter arc-shaped steel pipe 1. Both inner wall protrusions 2 and outer wall protrusions 3 are hemispherical. Both are circumferentially arranged, and their installation positions on the gradually changing inner diameter arc-shaped steel pipe 1 are corresponding inside and outside.

[0033] The gradually changing inner diameter arc-shaped steel pipe 1 is filled with core concrete 5 and outer concrete 6 on the inside and outside, respectively. The outer concrete 6 prevents the through bolts 4 and the gradually changing inner diameter arc-shaped steel pipe 1 from being exposed and corroded, thus extending their service life.

[0034] Example 1: In actual engineering, a large number of gradually changing inner diameter steel pipes with protruding particles attached to the steel wall are prefabricated in the factory. The bolt hole positions are accurately measured and marked at the upper and lower ends of the steel pipes in advance, and the bolt holes are pre-reserved during the fabrication of the steel pipes. First, through bolts 4 are inserted before the core concrete 5. The through bolts 4 are inserted from one end bolt hole, through the corresponding hole inside the steel pipe and on the other side, and the nuts are tightened. Initial tightening is performed first, followed by final tightening.

[0035] Based on the above operation, the core concrete 5 is filled in multiple stages from bottom to top. After the lower section of concrete has solidified, a new section is poured. The gradually changing inner diameter arc-shaped steel pipe 1 restricts the lateral expansion of the concrete through its own rigidity, generating a circumferential constraint force and compacting the density of the core concrete 5. The core concrete 5 and the protrusions 2 on the inner wall of the steel pipe interact and interlock, increasing the actual contact area between the inner wall of the steel pipe and the concrete. After the core concrete is poured, during the curing process (steam curing), the nuts are tightened.

[0036] After the core concrete 5 has cured, the outer concrete 6 is poured. This involves binding reinforcing bars to the outside of the gradually changing inner diameter arc-shaped steel pipe 1, installing formwork, pouring concrete, removing the formwork, and curing the concrete. During the installation of the reinforced concrete formwork, a pre-reserved bolt hole sealing structure is used. After pouring the concrete, cement is directly poured to fill the pre-reserved bolt holes. The end reinforcing bars of the ground beam are anchored into the outer concrete, and the bends are welded to the steel pipe using a single-sided welding method. The outer concrete 6 and the protrusions 3 on the outer wall of the steel pipe interact and interlock, increasing the actual contact area between the outer wall of the steel pipe and the outer concrete 6.

[0037] Example 2: For the structure to be reinforced, the steel-concrete composite column can be reinforced with an outer casing according to this technical solution. A large number of gradually changing inner diameter steel pipes with protruding particles attached to the steel wall are prefabricated in the factory. The bolt hole positions are accurately measured and marked at the upper and lower ends of the steel pipes beforehand, and bolt holes are pre-drilled. To facilitate on-site installation of the gradually changing inner diameter steel pipes, they are prefabricated longitudinally in two or three parts. First, the steel pipes are assembled and welded on-site. Then, through bolts 4 are inserted, passing through the bolt holes at one end of the gradually changing inner diameter arc-shaped steel pipe 1, through the corresponding holes inside the gradually changing inner diameter steel pipe and connecting components, and the nuts are tightened, initially tightened and then finally tightened.

[0038] Following the above procedure, the steel pipe is fixed, and concrete is poured in multiple stages from bottom to top. After the lower section of concrete has solidified, a new section is poured. The core concrete 5 and the protrusions 2 on the inner wall of the steel pipe interact and interlock, increasing the actual contact area between the inner wall of the steel pipe and the concrete. This ensures a tight bond between the steel pipe, the core concrete, and the column to be reinforced. After the core concrete is poured, the nuts are tightened during the curing process (steam curing).

[0039] The following is the same as in Specific Embodiment 1. Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A steel-concrete composite column with gradually changing inner diameter, characterized in that: It includes a gradually changing inner diameter arc-shaped steel pipe (1), which is provided with through bolts (4), and the wall surface of the gradually changing inner diameter arc-shaped steel pipe (1) is provided with several protruding particles. The gradually changing inner diameter arc-shaped steel pipe (1) is filled with core concrete (5) and outer concrete (6) on the inside and outside respectively.

2. The gradually changing inner diameter steel tube concrete column according to claim 1, characterized in that: The wall thickness of the middle section of the gradually changing inner diameter arc-shaped steel pipe (1) is less than the wall thickness of both ends.

3. The gradually changing inner diameter steel tube concrete column according to claim 1, characterized in that: A plurality of the aforementioned through bolts (4) form a through bolt group, and the through bolt group is provided with a plurality of bolts; The through bolts (4) in the through bolt group are arranged in an alternating manner.

4. The gradually changing inner diameter steel tube concrete column according to claim 3, characterized in that: The angle range between the staggered through bolts (4) in the through bolt group is 0-180°.

5. The gradually changing inner diameter steel tube concrete column according to claim 1, characterized in that: The protruding particles include protruding particles (2) on the inner wall of the steel pipe and protruding particles (3) on the outer wall of the steel pipe, and the protruding particles (2) on the inner wall of the steel pipe and the protruding particles (3) on the outer wall of the steel pipe are respectively disposed on the inner wall and the outer wall of the arc-shaped steel pipe (1) with a gradually changing inner diameter.

6. The gradually changing inner diameter steel tube concrete column according to claim 1, characterized in that: The two ends of the through bolt (4) are fixed by nuts, and the nuts are close to the outer wall of the arc-shaped steel pipe (1) with a gradually changing inner diameter.

7. The gradually changing inner diameter steel tube concrete column according to claim 1, characterized in that: The side wall of the gradually changing inner diameter arc-shaped steel pipe (1) has bolt holes, and the through bolt (4) passes through the bolt holes.

8. The gradually changing inner diameter steel tube concrete column according to claim 5, characterized in that: The protrusions (2) on the inner wall of the steel pipe and the protrusions (3) on the outer wall of the steel pipe are both hemispherical.

9. The gradually changing inner diameter steel tube concrete column according to claim 5, characterized in that: The inner wall protrusions (2) and outer wall protrusions (3) of the steel pipe are both arranged circumferentially, and the inner wall protrusions (2) and outer wall protrusions (3) of the steel pipe are positioned in a corresponding manner on the gradually changing inner diameter arc-shaped steel pipe (1).

10. The gradually changing inner diameter steel tube concrete column according to claim 7, characterized in that: The gap between the bolt hole and the through bolt (4) is filled with concrete.

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