Hollow interlayer steel pipe concrete column splicing device and splicing method thereof

Abstract

The invention discloses a hollow interlayer concrete-filled steel tube column splicing device and a splicing method thereof.The hollow interlayer concrete-filled steel tube column splicing device comprises an upper hollow interlayer concrete-filled steel tube column and a lower hollow interlayer concrete-filled steel tube column, and each hollow interlayer concrete-filled steel tube column comprises an outer steel tube, an inner steel tube and interlayer concrete located in a hollow interlayer; comprising an anchoring steel bar assembly used for connecting an upper section of interlayer concrete and a lower section of interlayer concrete, at least two rows of studs located on the inner wall of each inner steel pipe and distributed in the annular direction, a connecting steel pipe, an upper steel plate located in the upper section of inner steel pipe and located above the connecting steel pipe and provided with a notch, and a lower steel plate located in the lower section of inner steel pipe and located below the connecting steel pipe and provided with a door leaf. The connecting steel pipe is provided with an upper self-locking clamping groove and a lower self-locking clamping groove, the stud at the upper section penetrates through the upper self-locking clamping groove, the stud at the lower section penetrates through the lower self-locking clamping groove, the upper steel plate, the connecting steel pipe and the lower steel plate form a cavity communicated with the interlayer, and the cavity and the interlayer are filled with integrated concrete. The defects of discontinuous stress, poor tensile strength and the like at the splicing position are effectively overcome.

Description

Technical Field

[0001] The 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 steel tube concrete columns are composed of inner and outer steel tubes and sandwich concrete. As a new composite structure, they have good mechanical properties, low steel consumption, high material utilization rate, and are easy to prefabricate and assemble. Therefore, they are widely used in high-rise structures, such as wind turbine tower structures, wind turbine lattice tower columns, and high-voltage transmission tower columns. However, at present, the splicing of hollow sandwich steel tube concrete columns mostly draws on the flange connection technology of pure steel tube structures, that is, the outer steel tubes of the upper and lower column components are bolted. For components with large cross-sectional dimensions, the inner steel tube can also be connected by an inner flange, but in actual projects, the inner steel tube size of the column component is usually small, and there is not enough space for flange connection, which causes the inner steel tube to be disconnected at the splicing site, discontinuous force transmission, and the upper and lower column sections to be easily separated when the tension is too large. For sandwich concrete, the interface adhesive used in traditional practices is prone to aging, and its durability is not easy to guarantee under the cyclic load of high-rise 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 the hollow sandwich steel tube concrete columns.

[0005] The 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: To achieve the above purpose, 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 anchoring steel bar assembly for connecting the upper and lower sandwich concrete, 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 notch 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 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 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 which are tightly interlocked and circumferentially distributed at the bottom of the upper sandwich concrete and L-shaped anchor steel bars which 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 matches 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 formed on the connecting steel pipe, and a second slot is formed 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 with an outer steel pipe flange for connecting the upper and lower sections of the hollow sandwich steel tube concrete column.

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

[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, anchor a number of circumferentially distributed U-shaped anchor steel bars in the bottom of the upper sandwich concrete, and the U-shaped anchor steel bars exceed the bottom surface of the sandwich concrete by a certain distance; when prefabricating the lower hollow sandwich steel tube concrete column, the sandwich concrete is not fully poured, and the pouring is stopped when it is a certain distance from the top surface, and at the same time, a number of circumferentially distributed L-shaped anchor steel bars are anchored, and the L-shaped anchor steel bars exceed the end surface of the sandwich concrete but do not exceed the top surface of the lower hollow sandwich steel tube concrete column; set at least two rows of circumferentially distributed bolts on the inner wall of the inner steel tube, weld the lower steel plate to the inner steel tube of the lower section, and weld the upper steel plate to the inner steel tube of the upper section;

[0017] The lower hollow sandwich steel tube concrete column is connected to 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. The connecting steel pipe is pressed downward. After the notch abuts against the bolt, the connecting steel pipe is rotated clockwise. After the connecting steel pipe cannot rotate, it is pressed downward 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 column with the upper self-locking notch of the connecting steel pipe, press 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, 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 and fix 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 effects of on-site welding and other operations on the construction quality, which helps the strength of the component to achieve the expected effect; 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 integral 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 synergistic force mechanism of concrete and studs and concrete and anchor bar assemblies. 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 adhesive and difficulty in ensuring long-term performance. Through the rotating self-locking device and integrated grouting connection technology, the stress performance of sandwich concrete and inner steel tube 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 a steel plate with a groove and a steel plate with a door leaf in the steel tube, so as to realize continuous grouting of multiple nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an isometric longitudinal cross-sectional stereogram 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 It is a three-dimensional diagram of the connecting steel pipe in the present invention;

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

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

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

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

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

[0029] Fig. 9 It is a longitudinal cross-sectional view of a multi-segment component after being connected 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 notches 12, second notches 13, upper self-locking slots 14, lower self-locking slots 15, and door leaf 16. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with 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 section of 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 sections of sandwich concrete, 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 section sandwich concrete, the L-shaped anchoring steel bar 11 is circumferentially distributed at the top of the lower section 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 section sandwich concrete is kept a certain distance from the top surface of the steel tube inside 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 tube inside 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 anchoring steel bars 10 and L-shaped anchoring steel bars 11 is the same, and the overhanging lengths and sizes 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 bolts 9 are arranged on the inner wall of each inner steel pipe, and the bolts 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, so as 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 with an outer steel pipe flange 7 for connecting the upper and lower sections of the hollow sandwich steel pipe 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 passing the bolts at the upper section and a lower self-locking slot 15 for passing the bolts at the lower section. The upper self-locking slot 14 and the lower self-locking slot 15 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 bolts, and the directions of the horizontal slots of the upper self-locking slot and the lower self-locking slot are opposite. 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 is provided with a semicircular slot on the basis of the F-shaped slot, and 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 limiting, and the diameter of the semicircular slot matches the diameter of the bolt 9 on the inner steel pipe 3, so as to ensure that the bolt 9 can be stuck on 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 the bolt 9 is just stuck in the slot after connection.

[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 in the upper section inner steel pipe, and the upper steel plate 6 is located above the connecting steel pipe. A circular notch with a stepped surface is provided at the center of the lower steel plate 5, and 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 plays a supporting role. The door leaf 16 can be opened to grout from top to bottom. After the grouting is completed, the door is closed as the bottom of the next layer of grouting operation, and the grouting operation and connection of each section of steel tube concrete are carried out in turn. The lower steel plate 5 is located in the lower section inner steel pipe 3, and the lower steel plate 5 is located below the connecting steel pipe 4. The surface of the lower steel plate 5 is paved with a film for preventing slurry leakage. A first notch 12 is provided on the connecting steel pipe 4, and a second notch 13 is provided at a position corresponding to the first notch in the lower section inner steel pipe. The position, shape and number of the first notch 12 and the second notch 13 are consistent. The connecting steel pipe 4 and the lower steel plate 5 form a cavity connected to the interlayer, and the cavity and the interlayer are filled with integral concrete. The present invention realizes integrated grouting in the cavity and the interlayer, strengthens the connection performance of the interlayer concrete and the inner steel pipe, thereby improving the integrity and stress performance of the splicing node.

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

[0036] Prefabricate the upper and lower sections of the hollow sandwich steel tube concrete column, and then transport them to the construction site for splicing; anchor a number of circumferentially distributed U-shaped anchor steel bars in the bottom of the upper sandwich concrete, and the U-shaped anchor steel bars exceed the bottom surface of the sandwich concrete by a certain distance; when prefabricating the lower section of the hollow sandwich steel tube concrete column, the sandwich concrete is not poured full, and the pouring is stopped at a certain distance from the top surface, and at the same time, a number of circumferentially distributed L-shaped anchor steel bars are anchored, and the L-shaped anchor steel bars exceed the end surface of the sandwich concrete but do not exceed the top surface of the lower section of the hollow sandwich steel tube concrete column; set at least two rows of circumferentially distributed bolts on the inner wall of the inner steel tube, fix the lower steel plate in the lower section inner steel tube, and fix the upper steel plate in the upper section inner steel tube;

[0037] like Figure 5 As shown, the lower hollow sandwich steel tube concrete column is connected to the connecting steel pipe. When connecting, align the bolts of the lower hollow sandwich steel tube concrete column with the lower self-locking notch on the connecting steel pipe for splicing. The connecting steel pipe is pressed downward. After the notch abuts against the bolts, the connecting steel pipe is rotated clockwise. After the connecting steel pipe cannot rotate, it is pressed downward again. The bolts are 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.

[0038] like Figure 6As shown, align the bolt on the upper hollow sandwich steel tube concrete column with the upper self-locking notch of the connecting steel pipe, press downward and insert it into the upper self-locking notch, and after the notch presses against the bolt, the upper hollow sandwich steel tube concrete column rotates clockwise until it cannot rotate, and the bolt is located in the horizontal notch of the upper self-locking notch, and 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; the bolt holes of the outer steel pipe flanges on the upper and lower hollow sandwich steel tube concrete columns are aligned and tightened 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, wraps the U-shaped anchor steel bar and the L-shaped anchor steel bar, and the pouring is stopped until the concrete slurry reaches the upper steel plate and overflows from the notch, thus completing the splicing;

[0040] Specifically, the door leaf on the lower steel plate of the upper component is opened, and the connecting part of the upper and lower components is grouted through the grooves on the lower steel plate and the upper steel plate 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; the grouting is from bottom to top, starting from the lower steel plate of the lower component, the slurry is filled, the studs are wrapped in turn, and the slurry flows 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, and then the pouring is stopped; then the door leaf of the upper component is close to the lower steel plate, and a film is laid on the surface, and the installation of the next component is carried out in this way, which can realize multi-node continuous grouting, such as Fig. 9 shown.

[0041] The present invention improves the shortcomings of the traditional hollow sandwich steel tube concrete column joint part, such as poor tensile performance and discontinuous force transmission of the inner steel tube. The present invention arranges bolts and pre-buried anchor bars in the sandwich concrete at the joint part of the upper and lower column sections, and uses the slotted connecting steel pipe as a transition section to ensure that the joint part is firm and stable through grouting. Specifically, the present invention welds a plurality 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 firstly 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 achieve 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 achieve self-locking. After the upper column is positioned, the outer steel pipe flange is first connected, and then the inside of the connecting steel pipe and the sandwich concrete cavity are grouted in an integrated manner. Therefore, the present invention can enhance the integrity of the spliced ​​part of the hollow sandwich steel tube concrete column, improve the stress performance, and prevent the spliced ​​part 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, 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, characterized in that: The invention comprises an anchoring steel bar assembly for connecting upper and lower sandwich concrete sections, 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 inner steel pipe sections, an upper steel plate (6) with a notch located in the upper inner steel pipe section and above the connecting steel pipe, and a lower steel plate (5) with a door leaf (16) located in the lower inner steel pipe section 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 section are filled with integral concrete.

2. A hollow sandwich steel tube concrete column splicing device according to claim 1, characterized in that: The anchoring steel bar assembly comprises U-shaped anchoring steel bars (10) which are tightly connected and circumferentially distributed at the bottom of the upper sandwich concrete and L-shaped anchoring steel bars (11) which are circumferentially distributed at the top of the lower sandwich concrete, wherein the U-shaped anchoring steel bars (10) 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 anchoring steel bars (11) 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.

3. A 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 include 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. A 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) has 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 matched with 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 with 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, anchor a number of circumferentially distributed U-shaped anchor steel bars in the bottom of the upper sandwich concrete, and the U-shaped anchor steel bars exceed the bottom surface of the sandwich concrete by a certain distance; when prefabricating the lower hollow sandwich steel tube concrete column, the sandwich concrete is not fully poured, and the pouring is stopped when it is a certain distance from the top surface, and at the same time, a number of circumferentially distributed L-shaped anchor steel bars are anchored, and the L-shaped anchor steel bars exceed the end surface of the sandwich concrete but do not exceed the top surface of the lower hollow sandwich steel tube concrete column; set at least two rows of circumferentially distributed bolts on the inner wall of the inner steel tube, weld the lower steel plate to the inner steel tube of the lower section, and weld the upper steel plate to the inner steel tube of the upper section; The lower hollow sandwich steel tube concrete column is connected to 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. The connecting steel pipe is pressed downward. After the notch abuts against the bolt, the connecting steel pipe is rotated clockwise. After the connecting steel pipe cannot rotate, it is pressed downward 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 downward and insert it into the upper self-locking notch, and after the notch presses against the bolt, the upper hollow sandwich steel tube concrete column rotates clockwise until it cannot rotate, and the bolt is located in the horizontal notch of the upper self-locking notch; while the upper hollow sandwich steel tube concrete column rotates, 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 and fix 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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