A hollow sandwich steel tube concrete column splicing device and splicing method

Abstract

The present invention discloses a hollow sandwich steel tube concrete column splicing device and a splicing method thereof, comprising upper and lower hollow sandwich steel tube concrete columns, the hollow sandwich steel tube concrete column comprising an outer steel tube, an inner steel tube, and a sandwich concrete located within the hollow sandwich, comprising an anchoring steel bar assembly for connecting the upper and lower sandwich concrete sections, at least two rows of circumferentially distributed bolts located on the inner wall of each inner steel tube, a connecting steel tube, an upper steel plate with a notch located within the upper inner steel tube and above the connecting steel tube, and a lower steel plate with a door leaf located within the lower inner steel tube and below the connecting steel tube, the connecting steel tube being provided with an upper self-locking slot for inserting the bolts at the upper section and a lower self-locking slot for inserting the bolts at the lower section, the upper steel plate, the connecting steel tube, and the lower steel plate forming a cavity connected to the sandwich, the cavity and the sandwich being filled with integral concrete. The present invention effectively improves defects such as discontinuous force and poor tensile strength at the splicing point.

Description

Technical Field

[0001] The present invention belongs to the technical field of civil engineering, and in particular relates to a hollow sandwich steel tube concrete column splicing device and a splicing method thereof. Background Art

[0002] Hollow sandwich concrete-filled steel tubular columns, composed of inner and outer steel tubes and a concrete sandwich layer, are an emerging composite structural form. They offer excellent mechanical properties, low steel consumption, high material efficiency, and ease of prefabrication and assembly. Consequently, they are widely used in tall structures such as wind turbine towers, lattice tower columns for wind turbines, and high-voltage transmission tower columns. However, current methods for joining hollow sandwich concrete-filled steel tubular columns often rely on flange connection techniques borrowed from pure steel tube structures, where the outer steel tubes of the upper and lower column segments are bolted together. For components with larger cross-sectional dimensions, internal flange connections can also be used for the inner steel tubes. However, in actual projects, the inner steel tubes of column components are typically smaller, leaving insufficient space for flange connections. This can lead to disconnection of the inner steel tubes at the joint, discontinuous force transmission, and the separation of the upper and lower column segments under excessive tension. Furthermore, the interfacial adhesive used in sandwich concrete is susceptible to aging, making its durability difficult to guarantee under the cyclic loading of tall structures.

[0003] Therefore, it is urgent to solve the above problems. Summary of the Invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a hollow sandwich steel tube concrete column splicing device, which effectively improves the defects of discontinuous force and poor tensile strength at the splicing points of hollow sandwich steel tube concrete columns.

[0005] A second object of the present invention is to provide a method for splicing a hollow sandwich steel tube concrete column splicing device.

[0006] Technical solution: In order to achieve the above objectives, the present invention discloses a hollow sandwich steel tube concrete column splicing device, comprising an upper and lower hollow sandwich steel tube concrete column, the hollow sandwich steel tube concrete column comprising an outer steel tube, an inner steel tube and a sandwich concrete located in the hollow sandwich, characterized in that it comprises an anchor steel bar assembly for connecting the upper and lower sandwich concrete sections, at least two rows of circumferentially distributed bolts located on the inner wall of each inner steel tube, a connecting steel pipe for connecting the upper and lower inner steel pipes, an upper steel plate with a slot located in the upper inner steel pipe and above the connecting steel pipe, and a lower steel plate with a door leaf located in the lower inner steel pipe and below the connecting steel pipe, the connecting steel pipe is provided with an upper self-locking slot for passing the bolts at the upper section and a lower self-locking slot for passing the bolts at the lower section, the upper steel plate, the connecting steel pipe and the lower steel plate constitute a cavity connected to the sandwich, and the cavity and the sandwich are filled with integral concrete.

[0007] Optionally, the anchor steel bar assembly includes U-shaped anchor steel bars that are tightly interlocked and circumferentially distributed at the bottom of the upper sandwich concrete and L-shaped anchor steel bars that are circumferentially distributed at the top of the lower sandwich concrete, wherein the U-shaped anchor steel bars extend beyond the bottom surface of the sandwich concrete by a certain distance, the top surface of the lower sandwich concrete is at a certain distance from the top surface of the steel pipe in the lower section, and the L-shaped anchor steel bars extend beyond the end surface of the lower sandwich concrete but do not exceed the top surface of the steel pipe in the lower section.

[0008] Optionally, the upper self-locking slot and the lower self-locking slot both include vertical slots and horizontal slots that are interconnected, wherein the number of horizontal slots is the same as the number of rows of corresponding pins, and the directions of the horizontal slots of the upper self-locking slot and the lower self-locking slot are opposite.

[0009] Optionally, the end of the horizontal notch of the lower self-locking slot has a semicircular notch for limiting.

[0010] Optionally, the outer diameter of the connecting steel pipe is matched with the inner diameter of the inner steel pipe, and the connecting steel pipe is tightly attached to the inner wall of the inner steel pipe.

[0011] Optionally, a first slot is provided on the connecting steel pipe, and a second slot is provided on the lower inner steel pipe at a position corresponding to the first slot, and the first slot and the second slot are consistent in position, shape and number.

[0012] Optionally, the end of the outer steel pipe is connected to an outer steel pipe flange for connecting the upper and lower sections of the hollow sandwich steel tube concrete column.

[0013] Optionally, a circular notch with a stepped surface is opened at the center of the lower steel plate, and the door leaf is connected to the circular notch.

[0014] Optionally, the surface of the lower steel plate is paved with a film for preventing slurry leakage.

[0015] Based on the same inventive concept, the present invention discloses a splicing method of a hollow sandwich steel tube concrete column splicing device, comprising the following steps:

[0016] Prefabricate upper and lower hollow sandwich steel tube concrete columns, anchoring a plurality of circumferentially distributed U-shaped anchor bars in the bottom of the sandwich concrete of the upper section, with the U-shaped anchor bars extending a certain distance beyond the bottom surface of the sandwich concrete. When prefabricating the sandwich concrete of the lower section, the sandwich concrete is not fully poured, and pouring is stopped at a certain distance from the top surface. At the same time, a plurality of circumferentially distributed L-shaped anchor bars are anchored therein, with the L-shaped anchor bars extending beyond the end surface of the sandwich concrete but not exceeding the top surface of the lower hollow sandwich steel tube concrete column. At least two rows of circumferentially distributed studs are set on the inner wall of the inner steel tube, and the lower steel plate is welded to the inner steel tube of the lower section, and the upper steel plate is welded to the inner steel tube of the upper section.

[0017] Connect the lower hollow sandwich steel tube concrete column with the connecting steel pipe. When connecting, align the bolt of the lower hollow sandwich steel tube concrete column with the lower self-locking notch on the connecting steel pipe for splicing. Press the connecting steel pipe downward. After the notch hits the bolt, rotate the connecting steel pipe clockwise. After the connecting steel pipe stops rotating, press it down again. The bolt is stuck in the semicircular notch of the lower self-locking notch. At the same time, the first notch is aligned with the second notch, so that the cavity of the connecting steel pipe is connected with the interlayer.

[0018] Align the bolt on the upper hollow sandwich steel tube concrete-filled column with the upper self-locking notch of the connecting steel pipe, press it downward and insert it into the upper self-locking notch. After the notch presses against the bolt, rotate the upper hollow sandwich steel tube concrete-filled column clockwise until it cannot rotate. The bolt is located in the horizontal notch of the upper self-locking notch. The L-shaped anchor steel bar on the lower hollow sandwich steel tube concrete-filled column passes through the U-shaped anchor steel bar on the upper hollow sandwich steel tube concrete-filled column, and the two are tied together. Align the bolt holes of the outer steel pipe flanges on the upper and lower hollow sandwich steel tube concrete-filled columns and tighten them with high-strength bolts.

[0019] The cavity formed by the upper steel plate, the connecting steel pipe and the lower steel plate is filled with concrete. The concrete enters the interlayer through the first notch and the second notch, wrapping the U-shaped anchor steel bars and the L-shaped anchor steel bars until the concrete slurry reaches the upper steel plate and overflows from the notch. Then the pouring is stopped and the splicing is completed.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention can realize on-site splicing, and the mechanical connection method reduces the construction difficulty, while avoiding the uncertain influence of on-site welding and other operations on the construction quality, which helps to achieve the expected strength of the component; the present invention ensures the tensile performance of the connection through the anchor steel bar assembly at the sandwich concrete and the self-locking connection of the stud and steel pipe, effectively avoiding the phenomenon that the structure is easy to disengage under tension; and adopts self-compacting concrete on-site local grouting at the connection to form an integrated concrete in the cavity of the connecting steel pipe and the upper and lower sandwich concrete cavities, and improves the integrity of the connection part through the coordinated force mechanism of concrete and studs and concrete and anchor bar assembly. The present invention effectively reduces the dependence of traditional hollow sandwich steel tube concrete column splicing nodes on external steel tubes, while overcoming the shortcomings of easy aging of concrete structural adhesives and difficulty in ensuring long-term performance. Through the rotary self-locking device and integrated grouting connection technology, the stress performance of sandwich concrete and inner steel tubes is fully utilized, and the material utilization rate and combination effect of the structure are improved in all directions, thereby enhancing the safety redundancy of the structure. It is of great significance to improve the safety performance of high-rise structures under extreme loads such as strong winds and strong earthquakes and to extend the fatigue life of high-rise structures under long-term random reciprocating loads. In addition, the present invention arranges steel plates with grooves and steel plates with door leaves in steel tubes, which can realize continuous grouting of multiple nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an isometric longitudinal cross-sectional perspective view of the present invention;

[0022] Figure 2 It is a longitudinal cross-sectional view of a section of a steel tube concrete member in the present invention;

[0023] Figure 3 A perspective view of the connecting steel pipes of the present invention;

[0024] Figure 4 It is a longitudinal cross-sectional view of each component in the present invention;

[0025] Figure 5 This is a longitudinal cross-sectional view of the lower column of the present invention after being connected to the connecting steel pipe;

[0026] Figure 6 It is a longitudinal cross-sectional view of the present invention after assembly;

[0027] Figure 7 This is a longitudinal cross-sectional view of the upper and lower end components of the present invention after connection;

[0028] Figure 8 A top view of the present invention;

[0029] Figure 9 It is a longitudinal cross-sectional view of a multi-segment component after connection in the present invention;

[0030] In the figure: outer steel pipe 1, sandwich concrete 2, inner steel pipe 3, connecting steel pipe 4, lower steel plate 5, upper steel plate 6, outer steel pipe flange 7, high-strength bolts 8, studs 9, U-shaped anchor steel bars 10, L-shaped anchor steel bars 11, first notch 12, second notch 13, upper self-locking slot 14, lower self-locking slot 15, door leaf 16. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] like Figure 1 and Figure 2As shown, the present invention discloses a hollow sandwich steel tube concrete column splicing device, comprising an upper and lower hollow sandwich steel tube concrete column, the hollow sandwich steel tube concrete column comprising an outer steel tube 1, an inner steel tube 3 and a sandwich concrete 2 located in the hollow sandwich, an anchoring steel bar assembly is used to connect the upper and lower sandwich concrete sections, the anchoring steel bar assembly comprises a U-shaped anchoring steel bar 10 and an L-shaped anchoring steel bar 11 that are tightly fastened to each other, the U-shaped anchoring steel bar 10 is circumferentially distributed at the bottom of the upper sandwich concrete, and the L-shaped anchoring steel bar 11 is circumferentially distributed at the top of the lower sandwich concrete, wherein the U-shaped anchoring steel bar 10 exceeds the bottom surface of the sandwich concrete by a certain distance, the top surface of the lower sandwich concrete is at a certain distance from the top surface of the steel pipe in the lower section, and the L-shaped anchoring steel bar 11 exceeds the end surface of the sandwich concrete in the lower section but does not exceed the top surface of the steel pipe in the lower section. The present invention can ensure a better connection effect between the sandwich concrete in the upper and lower column sections. The number of U-shaped anchor steel bars 10 and L-shaped anchor steel bars 11 is the same, and the overhanging length and size are matched, ensuring that the two can be tightly fastened together when the upper column section rotates.

[0033] like Figure 4 and Figure 7 As shown, at least two rows of circumferentially distributed studs 9 are provided on the inner wall of each inner steel pipe. The studs 9 are symmetrically distributed on the inner wall. The connecting steel pipe 4 is used to connect the upper and lower sections of the inner steel pipe. The outer diameter of the connecting steel pipe 4 is adapted to the inner diameter of the inner steel pipe 3. The connecting steel pipe 4 is tightly attached to the inner wall of the inner steel pipe 3. The outer diameter of the connecting steel pipe 4 is slightly smaller than the inner diameter of the inner steel pipe 3 to ensure that the connecting steel pipe 4 can be tightly attached to the inner wall of the inner steel pipe 3 during splicing. The end of the outer steel pipe 1 is connected to an outer steel pipe flange 7 for connecting the upper and lower sections of the hollow sandwich steel tube concrete column. The outer steel pipe flange 7 is provided with a plurality of stiffening ribs and a plurality of bolt holes, and is connected and fixed by high-strength bolts 8, as shown in FIG. Figure 8 As shown. Figure 3 As shown, the connecting steel pipe 4 is provided with an upper self-locking slot 14 for receiving the upper section bolts, and a lower self-locking slot 15 for receiving the lower section bolts. Both the upper self-locking slot 14 and the lower self-locking slot 15 comprise interconnected vertical and horizontal slots. The number of horizontal slots is the same as the number of rows of corresponding bolts. The horizontal slots of the upper and lower self-locking slots are oriented in opposite directions. In this embodiment, there are two rows of bolts 9, and the corresponding upper self-locking slot 14 is an F-shaped slot with two rows of horizontal slots. The lower self-locking slot 15 adds a semicircular slot to the F-shaped slot. The semicircular slot is located on the upper side of the front end of the horizontal slot and is excavated upward. The end of the horizontal slot of the lower self-locking slot 15 has a semicircular slot for positioning. The diameter of the semicircular slot matches the diameter of the bolts 9 on the inner steel pipe 3, ensuring that the bolts 9 can be locked in the semicircular slot. The width of the upper self-locking slot 14 and the lower self-locking slot 15 corresponds to the diameter of the bolt 9 on the inner steel pipe 3; the distance between the horizontal slots is equal to the distance between two adjacent rows of bolts 9, and the two correspond one to one, so that after connection, the bolt 9 is just stuck in the slot.

[0034] A circular notch is provided at the center of the upper steel plate 6 for subsequent grouting operations. The upper steel plate 6 is located within the upper section of the inner steel pipe and above the connecting steel pipe. A circular notch with a stepped surface is provided at the center of the lower steel plate 5. The stepped surface forms a door frame. The door leaf 16 is connected to the door frame at the circular notch. When the door leaf 16 is closed, it supports the door leaf. When the door leaf 16 is opened, grouting can be carried out from top to bottom. After grouting is completed, the door is closed, serving as the bottom for the next layer of grouting operations. Grouting operations and connections of each section of steel tube concrete are carried out in sequence. The lower steel plate 5 is located within the lower section of the inner steel pipe 3 and below the connecting steel pipe 4. A film is laid on the surface of the lower steel plate 5 to prevent grout leakage. A first notch 12 is provided on the connecting steel pipe 4, and a second notch 13 is provided on the lower section of the inner steel pipe at a position corresponding to the first notch. The first notch 12 and the second notch 13 are consistent in position, shape, and number. The connecting steel pipe 4 and the lower steel plate 5 form a cavity connected to the interlayer, which is filled with integral concrete. The present invention implements integrated grouting in the cavity and interlayer, strengthening the connection between the interlayer concrete and the inner steel pipe, thereby improving the integrity and mechanical performance of the splicing node.

[0035] The present invention provides a method for splicing a hollow sandwich steel tube concrete column splicing device, comprising the following steps:

[0036] The upper and lower hollow sandwich steel tube concrete columns are prefabricated and then transported to the construction site for splicing. A number of circumferentially distributed U-shaped anchor bars are anchored in the bottom of the upper sandwich concrete, with the U-shaped anchor bars extending a certain distance beyond the bottom surface of the sandwich concrete. When prefabricating the lower hollow sandwich steel tube concrete column, the sandwich concrete is not fully poured, and pouring is stopped at a certain distance from the top surface. At the same time, a number of circumferentially distributed L-shaped anchor bars are anchored, with the L-shaped anchor bars extending beyond the end surface of the sandwich concrete but not exceeding the top surface of the lower hollow sandwich steel tube concrete column. At least two rows of circumferentially distributed bolts are set on the inner wall of the inner steel tube, and the lower steel plate is fixed to the inner steel tube of the lower section, and the upper steel plate is fixed to the inner steel tube of the upper section.

[0037] like Figure 5 As shown, the lower section of the hollow sandwich steel tube concrete-filled column is connected to the connecting steel pipe. When connecting, align the bolts of the lower section of the hollow sandwich steel tube concrete-filled column with the lower self-locking notch on the connecting steel pipe for splicing. Press the connecting steel pipe downward, and after the notch hits the bolt, rotate the connecting steel pipe clockwise. After the connecting steel pipe stops rotating, press it down again, and the bolt is stuck in the semicircular notch of the lower self-locking notch. At the same time, the first notch is aligned with the second notch, so that the cavity of the connecting steel pipe is connected to the interlayer.

[0038] like Figure 6As shown, align the bolt on the upper hollow sandwich steel tube concrete-filled column with the upper self-locking notch of the connecting steel pipe, press it downward and insert it into the upper self-locking notch. After the notch presses against the bolt, the upper hollow sandwich steel tube concrete-filled column is rotated clockwise until it cannot rotate. The bolt is located in the horizontal notch of the upper self-locking notch. The L-shaped anchor steel bar on the lower hollow sandwich steel tube concrete-filled column passes through the U-shaped anchor steel bar on the upper hollow sandwich steel tube concrete-filled column, and the two are tied together. Align the bolt holes of the outer steel pipe flanges on the upper and lower hollow sandwich steel tube concrete-filled columns and tighten them with high-strength bolts.

[0039] The cavity formed by the upper steel plate, the connecting steel pipe and the lower steel plate is filled with concrete. The concrete enters the interlayer through the first notch and the second notch, wrapping the U-shaped anchor steel bars and the L-shaped anchor steel bars until the concrete slurry reaches the upper steel plate and overflows from the notch. Then, pouring is stopped and the splicing is completed.

[0040] Specifically, the door leaf on the lower steel plate of the upper component is opened, and the connection part of the upper and lower components is grouting through the grooves on the lower and upper steel plates with a pipe. At this time, the door leaf of the lower component should be close to the lower steel plate. If necessary, a layer of film can be laid on its surface to prevent slurry leakage; grouting is from bottom to top, starting from the lower steel plate of the lower component to fill the slurry, wrapping the studs in turn, flowing through the first and second grooves into the interlayer, wrapping the U-shaped anchor steel bars and the L-shaped anchor steel bars, until the slurry reaches the upper steel plate of the upper component and overflows from the groove, then stop pouring; then the door leaf of the upper component is close to the lower steel plate, and a film is laid on the surface. In this way, the installation of the next component is carried out, and multi-node continuous grouting can be achieved, such as Figure 9 shown.

[0041] The present invention improves the shortcomings of the traditional hollow sandwich steel tube concrete column splicing part, such as poor tensile performance and discontinuous force transmission of the inner steel tube. The present invention arranges bolts and pre-embedded anchor bars in the sandwich concrete at the splicing part of the upper and lower column sections, and uses the slotted connecting steel pipe as a transition section to ensure that the splicing part is firm and stable through grouting. Specifically, the present invention welds a number of bolts along the circumferential direction on the inner wall of the inner steel pipe. When the upper and lower sections are connected, the lower notch of the connecting steel pipe is first rotated to connect with the inner steel pipe bolt of the lower section column to form a To achieve self-locking, the steel pipe bolts in the upper column are aligned with the upper notches of the connecting steel pipes and rotated and spliced ​​to form self-locking; at the same time, the anchor bars in the sandwich concrete of the upper and lower sections are also overlapped with each other through rotation to form self-locking; after the upper column is positioned, the outer steel pipe flange is connected first, and then the inside of the connecting steel pipe and the sandwich concrete cavity are grouting integratedly; therefore, the present invention can enhance the integrity of the splicing part of the hollow sandwich steel tube concrete column, improve the stress performance, and prevent the splicing parts from being damaged due to insufficient tensile bearing capacity under extreme loads.

Claims

1. A hollow sandwich steel tube concrete column splicing device, comprising upper and lower hollow sandwich steel tube concrete columns, wherein the hollow sandwich steel tube concrete column comprises an outer steel tube (1), an inner steel tube (3) and a sandwich concrete (2) located in the hollow sandwich, characterized in that: The invention comprises an anchoring steel bar assembly for connecting the upper and lower sections of sandwich concrete, at least two rows of circumferentially distributed bolts (9) located on the inner wall of each inner steel pipe, a connecting steel pipe (4) for connecting the upper and lower sections of the inner steel pipe, an upper steel plate (6) with a slot located in the upper section of the inner steel pipe and above the connecting steel pipe, and a lower steel plate (5) with a door leaf (16) located in the lower section of the inner steel pipe and below the connecting steel pipe, wherein the connecting steel pipe (4) is provided with an upper self-locking slot (14) for passing the bolts at the upper section and a lower self-locking slot (15) for passing the bolts at the lower section, and the upper steel plate (6), the connecting steel pipe (4) and the lower steel plate (5) form a cavity connected to the sandwich, and the cavity and the sandwich are filled with integral concrete.

2. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The anchoring steel bar assembly comprises a U-shaped anchoring steel bar (10) which is circumferentially distributed on the bottom of the upper sandwich concrete and an L-shaped anchoring steel bar (11) which is circumferentially distributed on the top of the lower sandwich concrete, wherein the U-shaped anchoring steel bar (10) exceeds the bottom surface of the sandwich concrete by a certain distance, the top surface of the lower sandwich concrete is at a certain distance from the top surface of the steel pipe in the lower section, and the L-shaped anchoring steel bar (11) exceeds the end surface of the lower sandwich concrete but does not exceed the top surface of the steel pipe in the lower section.

3. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The upper self-locking slot (14) and the lower self-locking slot (15) both comprise vertical slots and horizontal slots that are interconnected, wherein the number of the horizontal slots is the same as the number of rows of corresponding bolts, and the directions of the horizontal slots of the upper self-locking slot and the lower self-locking slot are opposite.

4. The hollow sandwich steel tube concrete column splicing device according to claim 3, characterized in that: The end of the horizontal notch of the lower self-locking slot (15) is provided with a semicircular notch for limiting.

5. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The outer diameter of the connecting steel pipe (4) is adapted to the inner diameter of the inner steel pipe (3), and the connecting steel pipe (4) is tightly attached to the inner wall of the inner steel pipe (3).

6. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The connecting steel pipe (4) is provided with a first notch (12), and the lower inner steel pipe is provided with a second notch (13) at a position corresponding to the first notch. The first notch (12) and the second notch (13) are consistent in position, shape and number.

7. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The end of the outer steel pipe (1) is connected to an outer steel pipe flange (7) for connecting the upper and lower sections of the hollow sandwich steel pipe concrete column.

8. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: A circular notch with a stepped surface is provided at the center of the lower steel plate (5), and the door leaf (16) is connected to the circular notch.

9. The hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The surface of the lower steel plate (5) is paved with a film for preventing slurry leakage.

10. A method for splicing a hollow sandwich steel tube concrete column splicing device according to any one of claims 1 to 9, characterized in that: The steps include: Prefabricate upper and lower hollow sandwich steel tube concrete columns, anchoring a plurality of circumferentially distributed U-shaped anchor bars in the bottom of the sandwich concrete of the upper section, with the U-shaped anchor bars extending a certain distance beyond the bottom surface of the sandwich concrete. When prefabricating the sandwich concrete of the lower section, the sandwich concrete is not fully poured, and pouring is stopped at a certain distance from the top surface. At the same time, a plurality of circumferentially distributed L-shaped anchor bars are anchored therein, with the L-shaped anchor bars extending beyond the end surface of the sandwich concrete but not exceeding the top surface of the lower hollow sandwich steel tube concrete column. At least two rows of circumferentially distributed studs are set on the inner wall of the inner steel tube, and the lower steel plate is welded to the inner steel tube of the lower section, and the upper steel plate is welded to the inner steel tube of the upper section. Connect the lower hollow sandwich steel tube concrete column with the connecting steel pipe. When connecting, align the bolt of the lower hollow sandwich steel tube concrete column with the lower self-locking notch on the connecting steel pipe for splicing. Press the connecting steel pipe downward. After the notch hits the bolt, rotate the connecting steel pipe clockwise. After the connecting steel pipe stops rotating, press it down again. The bolt is stuck in the semicircular notch of the lower self-locking notch. At the same time, the first notch is aligned with the second notch, so that the cavity of the connecting steel pipe is connected with the interlayer. Align the bolt on the upper hollow sandwich steel tube concrete column with the upper self-locking notch of the connecting steel pipe, press it downward and insert it into the upper self-locking notch. After the notch presses against the bolt, the upper hollow sandwich steel tube concrete column is rotated clockwise until it cannot rotate. The bolt is located in the horizontal notch of the upper self-locking notch. While the upper hollow sandwich steel tube concrete column is rotating, the L-shaped anchor steel bar on the lower hollow sandwich steel tube concrete column passes through the U-shaped anchor steel bar on the upper hollow sandwich steel tube concrete column, and the two are tied together. Align the bolt holes of the outer steel pipe flanges on the upper and lower hollow sandwich steel tube concrete columns and tighten them with high-strength bolts. The cavity formed by the upper steel plate, the connecting steel pipe and the lower steel plate is filled with self-compacting concrete. The concrete enters the interlayer through the first notch and the second notch, wrapping the U-shaped anchor steel bars and the L-shaped anchor steel bars until the concrete slurry reaches the upper steel plate and overflows from the notch. Then the pouring is stopped and the splicing is completed.

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