An assembled CFST-RC column equal-section conversion node and its construction method

Abstract

The present invention relates to an assembled CFST-RC column cross-section conversion node and a construction method thereof, comprising the following steps: pouring the lower half of a perforated steel pipe into a reinforced concrete column and reserving a grouting channel; installing the steel pipe above the reinforced concrete column; vertically inserting a positioning device downward from the top of the steel pipe, pushing the clip outward, and inserting it into the corresponding shear ring interval; and grouting the cavity between the perforated steel pipe and the steel pipe through the grouting channel. The beneficial effects of the present invention are as follows: the perforated steel pipe is inserted between the shear rings through several layers of clips, which acts as a bite, thereby achieving good force transmission; and the end of the grouting channel provided on the top surface of the reinforced concrete column is located outside the perforated steel pipe. During the grouting process, all bubbles between the steel pipe and the perforated steel pipe are squeezed upward, effectively ensuring the concrete density outside the perforated steel pipe. After the grouting material is poured and hardened into shape, the grouting material between each adjacent row of shear rings can be approximated as several short compression columns, which jointly bear the shear force.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel structures and composite structures, and in particular relates to an assembled CFST-RC column iso-section conversion node and a construction method thereof. Background Art

[0002] In actual engineering projects for large-scale, high-rise and super-high-rise public infrastructure projects, such as airport terminals, large stadiums, and bridges, the upper spatial structure roof has a large span and high floor height, resulting in high slenderness of the supporting columns, which in turn creates significant internal forces under load. Meanwhile, the lower frame structure has low floor heights and is connected to the foundation, necessitating high durability requirements. Therefore, in actual projects, upper concrete-filled steel tubular columns and lower reinforced concrete columns are often used as the load-bearing structure for these buildings. These two types of columns are connected through transfer nodes, transmitting internal forces such as compression, bending, and shear between the upper and lower floors.

[0003] Currently, CFST-RC column transition joints commonly used in engineering projects can be classified into embedded, end-supported, and externally packaged types. While these structures meet strength and stability requirements, they often suffer from complex construction, difficult construction, and low material utilization. Furthermore, under the same load, the cross-sectional area of ​​reinforced concrete columns is larger than that of steel tube concrete columns, resulting in inconsistent cross-sectional areas between the upper and lower columns. Existing projects often insert a layer of steel tube concrete into the lower reinforced concrete column. However, this method is relatively conservative, results in significant material waste, and has drawbacks such as uneven cross-sections at the joint location and an unsightly appearance.

[0004] Therefore, it is urgent to design an equal-section conversion node with equal cross-sections of the upper and lower columns, which has the characteristics of easy assembly and low construction difficulty. On the premise of meeting the safety and normal use requirements such as strength, stiffness, and stability, it can increase the utilization rate of building space and reduce the amount of building materials, and has high engineering application significance. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide an assembled CFST-RC column equal-section conversion node and a construction method thereof.

[0006] This assembled CFST-RC column equal section conversion node includes: a steel tube concrete column, a reinforced concrete column, a perforated steel pipe and a positioning device, wherein the steel tube concrete column is arranged above the reinforced concrete column, and the perforated steel pipe is inserted at the connection node between the steel tube concrete column and the reinforced concrete column;

[0007] The lower half of the perforated steel pipe is cast in the reinforced concrete column, and several layers of openings are opened at different heights in the upper half of the perforated steel pipe. The several openings in each layer are arranged in a circumferential direction, and a clip is inserted horizontally in each opening. Several layers of shear rings are provided corresponding to the openings on the inner wall of the steel tube concrete column; when the positioning device is inserted into the perforated steel pipe, the clip extends from the inside of the opening to the outside of the perforated steel pipe and is inserted between the shear rings.

[0008] Preferably, the bottom of the buckle is a plane, the top end facing the inside of the perforated steel pipe is a downward inclined surface, the top end facing the outside of the perforated steel pipe is a plane, a socket is provided on the plane, a cylindrical cavity is provided above the opening of the perforated steel pipe corresponding to the socket, a pin is inserted in the cylindrical cavity, and a spring is provided between the top of the pin and the top of the cylindrical cavity; the bottom end of the pin is wedge-shaped, and the side of the socket close to the inside of the perforated steel pipe is an inclined surface.

[0009] Preferably, a roller is provided at the inclined end facing the inner side of the perforated steel pipe. When the positioning device is inserted into the perforated steel pipe, the outer wall of the positioning device rests on the roller. When the positioning device moves downward, the roller rolls on the outer wall of the positioning device.

[0010] Preferably, the reinforced concrete column includes vertical longitudinal bars, which are welded to the outer surface of the perforated steel pipe; the positioning device includes a perforated ring and a thin-walled steel pipe, the outer diameter of the thin-walled steel pipe is less than or equal to the inner wall of the perforated steel pipe, the perforated ring is fixed to the top of the thin-walled steel pipe, and an opening is provided on the perforated ring for the vertical longitudinal bars to pass through and the concrete slurry to flow out.

[0011] The construction method of this assembled CFST-RC column equal section conversion node includes the following steps:

[0012] Step 1: Tie the reinforced concrete column reinforcement cage and set the vertical longitudinal reinforcement;

[0013] Step 2: Insert the lower half of the perforated steel pipe into the reinforced concrete column pouring area and weld it to the vertical longitudinal reinforcement;

[0014] Step 3: Support the formwork and cast the reinforced concrete column, cast the lower half of the perforated steel pipe into the reinforced concrete column, and reserve a grouting channel extending to the top surface of the reinforced concrete column;

[0015] Step 4: Install the steel pipe above the reinforced concrete column;

[0016] Step 5: Insert the positioning device vertically downward from the top of the steel pipe. The positioning device contacts the buckles in layers from top to bottom in sequence and pushes the buckles outward and inserts them into the corresponding shear ring intervals.

[0017] Step 6: Grout the cavity between the perforated steel pipe and the steel pipe through the grouting channel. The slurry overflows from the top of the positioning device and flows into the perforated steel pipe. The construction of this conversion node is completed after the slurry is poured until it reaches the top surface of the steel pipe.

[0018] Preferably, one end of the grouting channel is provided on the side wall of the reinforced concrete column, and the other end is provided on the top surface of the reinforced concrete column, and the end of the grouting channel provided on the top surface of the reinforced concrete column is located outside the perforated steel pipe. In step six, grouting is performed from the end of the grouting channel provided on the side wall of the reinforced concrete column, and the slurry is injected from the end of the grouting channel provided on the top surface of the reinforced concrete column into the cavity between the perforated steel pipe and the steel pipe. After the slurry overflows from the top of the cavity between the perforated steel pipe and the steel pipe, it enters the interior of the perforated steel pipe, and pours the gap between the perforated steel pipe and the positioning device and the interior of the positioning device.

[0019] Preferably, in step three, a slurry outlet channel is reserved when the reinforced concrete column is cast, one end of the slurry outlet channel is opened at the top of the reinforced concrete column inside the perforated steel pipe, and the other end is opened at the side wall of the reinforced concrete column below the bottom end of the perforated steel pipe; in step six, the slurry overflows from the top of the cavity between the perforated steel pipe and the steel pipe, enters the inside of the perforated steel pipe, and flows out from the side wall of the reinforced concrete column through the slurry outlet channel. When the flow rate of the slurry flowing out from one end of the slurry outlet channel opened at the side wall of the reinforced concrete column is uniform, the slurry outlet channel is blocked from one end of the side wall of the reinforced concrete column.

[0020] The beneficial effects of the present invention are:

[0021] 1) The node structure of the present invention is simple, and no stirrups are arranged in the node area, which avoids the problem of dense steel bars in the node area of ​​the traditional conversion node, making it difficult to construct. At the same time, it avoids the tedious construction caused by the traditional welding work with longitudinal bars in the steel pipe, greatly reducing the construction difficulty and improving the work effect; the perforated steel pipe is inserted between the shear rings through several layers of buckles, which plays a bite effect and makes the force transmission good; and the end of the grouting channel provided on the top surface of the reinforced concrete column is located outside the perforated steel pipe. During the grouting process, all the bubbles between the steel pipe and the perforated steel pipe are squeezed upward, effectively ensuring the density of the concrete outside the perforated steel pipe. After the grouting material is poured and hardened into shape, the grouting material between each adjacent row of shear rings can be approximated as several short compressed columns, which jointly bear the shear force.

[0022] 2) The node in the present invention greatly optimizes the traditional construction method of inserting the upper steel tube concrete column, and realizes the reasonable transition between the upper steel tube concrete column and the lower reinforced concrete column while meeting the performance requirements. The cross-sections of the upper and lower columns are consistent, so that the cross-section of the node position is flat and the form is beautiful, and it can improve space utilization and save building materials. The lower half of the perforated steel tube is cast in the reinforced concrete column, which can effectively strengthen the reliable connection between the upper steel tube concrete column and the lower reinforced concrete column, so that the stiffness change has better continuity and improves the strength and ductility of the transition node.

[0023] 3) In the present invention, a pin for temporarily locking the buckle is provided above the opening of the perforated steel pipe. The pin is pressed into the insertion hole on the upper surface of the buckle by a spring, so that the buckle will not fall out of the opening when the positioning device is not inserted. A roller is provided at the inner end of the buckle. After the positioning device is inserted, the roller rolls on the outer wall of the positioning device, so that the friction between the positioning device and the buckle does not affect the lower insertion of the positioning device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of a uniform cross-section conversion node of the present invention;

[0025] Figure 2a It is a structural schematic diagram of a perforated steel pipe welded with vertical longitudinal reinforcements according to the present invention;

[0026] Figure 2b This is a front view of a perforated steel pipe welded with vertical longitudinal reinforcement according to the present invention.

[0027] Figure 2c It is a top view of a perforated steel pipe welded with vertical longitudinal reinforcement according to the present invention;

[0028] Figure 3a It is a structural schematic diagram of the buckle of the present invention;

[0029] Figure 3b This is a schematic structural diagram of the lower buckle of the present invention from another angle;

[0030] Figure 3c is a side view of the buckle of the present invention;

[0031] Figure 3d is a top view of the buckle of the present invention;

[0032] Figure 4a This is a schematic diagram of the buckle of the present invention when it is not inserted into the steel pipe;

[0033] Figure 4b This is a schematic diagram of the buckle of the present invention when it is inserted into a steel pipe;

[0034] Figure 5a It is a structural schematic diagram of the positioning device of the present invention;

[0035] Figure 5b This is a front view of the positioning device of the present invention

[0036] Figure 5c is a top view of the positioning device of the present invention;

[0037] Figure 6a is a schematic diagram of the positioning device of the present invention when it is not inserted;

[0038] Figure 6b It is a schematic diagram of the positioning device of the present invention after insertion.

[0039] Explanation of the accompanying reference numerals: steel tube concrete column 1, reinforced concrete column 2, perforated steel tube 3, positioning device 4, steel tube 101, shear ring 102, vertical longitudinal reinforcement 201, buckle 301, socket 3011, pin 3012, spring 3013, columnar cavity 3014, roller 3015, perforated ring 401, thin-walled steel tube 402, grouting channel 501, grouting channel 502. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the following examples. The following examples are provided only to facilitate understanding of the present invention. It should be noted that, without departing from the principles of the present invention, it is possible for a person skilled in the art to make various modifications to the present invention, and such improvements and modifications fall within the scope of the claims of the present invention.

[0041] Example 1

[0042] As an example, Figures 1 to 6b As shown, the assembled CFST-RC column equal-section conversion node includes: a steel tube concrete column 1, a reinforced concrete column 2, a perforated steel pipe 3 and a positioning device 4. The steel tube concrete column 1 is arranged above the reinforced concrete column 2, and the perforated steel pipe 3 is inserted at the connection node between the steel tube concrete column 1 and the reinforced concrete column 2.

[0043] like Figures 1 to 2b As shown, the reinforced concrete column 2 includes vertical longitudinal bars 201 that meet the minimum reinforcement ratio requirement. The minimum distance between each vertical longitudinal bar 201 and the column axis is equal to the outer diameter of the perforated steel tube 3. That is, each vertical longitudinal bar 201 is arranged circumferentially close to the perforated steel tube 3, and the vertical longitudinal bars 201 are welded to the outer surface of the perforated steel tube 3. The protruding length of the vertical longitudinal bars 201 in the reinforced concrete column 2 is greater than the length of the top surface of the perforated steel tube 3 extending into the concrete of the upper steel tube concrete column 1, and the minimum anchorage length requirement must be met to ensure good bonding between the steel tube concrete column 1 and the vertical longitudinal bars 201, thereby ensuring good transmission of the internal forces of the steel tube concrete 1 to the vertical longitudinal bars 201 and the lower reinforced concrete column 2. The vertical longitudinal reinforcement 201 in the reinforced concrete column 2 is arranged at the midline position of the spacing between adjacent rows of openings in the perforated steel pipe 3 and is welded to the corresponding position of the perforated steel pipe 3, so that the vertical longitudinal reinforcement 201 in the column is arranged symmetrically, the structural column has a good stress form, strong stability, and can meet the structural requirements.

[0044] like Figure 1 As shown, multiple rows of shear rings 102 are welded on the inner wall of the steel tube of the concrete-filled steel tube column 1, and the spacing between adjacent rows of shear rings 102 is equal.

[0045] The outer diameter of the open steel pipe 3 is smaller than the inner diameter of the steel tube concrete column 1 and the reinforced concrete column 2, and it is coaxially arranged with the steel tube concrete column 1 and the reinforced concrete column 2. The reinforced concrete column 2 is cast first, and the lower half of the open steel pipe 3 is cast in the reinforced concrete column 2. The central cross-section position of the open steel pipe 3 is flush with the top surface of the reinforced concrete column 2.

[0046] like Figure 6a and Figure 6b As shown, the upper half of the perforated steel pipe 3 is provided with several layers of openings at different heights. Each adjacent layer of openings is equally spaced, and the openings in each layer are arranged circumferentially, with equal angles between adjacent openings. A clip 301 is inserted horizontally into each opening. When the positioning device 4 is inserted into the perforated steel pipe 3, the clip 301 is squeezed out of the opening, with the outer end of the clip 301 inserted between the shear rings 102.

[0047] like Figures 5a to 5c As shown, the positioning device 4 includes a perforated ring 401 and a thin-walled steel pipe 402. The outer diameter of the thin-walled steel pipe 402 is slightly smaller than the inner diameter of the perforated steel pipe 3, and the cross-sections of the upper and lower ends are perpendicular to the pipe axis. The perforated ring 401 is fixed to the top of the thin-walled steel pipe 402. The perforated ring 401 is made of steel. The outer diameter of the perforated ring 401 is slightly smaller than the inner diameter of the perforated steel pipe 3, leaving a small gap between the two for easy assembly. The inner diameter of the perforated ring 401 is equal to or slightly larger than the inner diameter of the perforated steel pipe 3, so that the perforated ring 401 can be stuck above the perforated steel pipe 3 after the positioning device 4 is inserted to the bottom. The perforated ring 401 is provided with fan-shaped openings, and the angles between the centerlines of adjacent fan-shaped openings are equal, which are used to allow the vertical longitudinal reinforcement 201 to pass through and the concrete slurry to flow out.

[0048] Example 2

[0049] As another embodiment, this second embodiment proposes, based on the first embodiment, a more specific assembled CFST-RC column equal-section conversion node, wherein the specific structure and operating principle of the clip 301 are as follows:

[0050] like Figures 3a to 3d As shown, the bottom of the clip 301 is flat, the top end facing the inside of the perforated steel pipe 3 is a downwardly inclined surface, and the top end facing the outside of the perforated steel pipe 3 is flat. The width of the upper and lower surfaces of the clip 301 is equal and greater than the height of the side surfaces, and the side height is slightly less than the distance between adjacent anti-shear rings 102, so that the clip 301 works in conjunction with the positioning device 4 during assembly.

[0051] like Figure 4a and Figure 4bAs shown, a hole 3011 is defined on the top planar surface of the buckle 301. A cylindrical cavity 3014 is defined above the opening of the perforated steel pipe 3, corresponding to the hole 3011. The cross-sectional area of ​​the cylindrical cavity 3014 is much smaller than the width of the opening. A latch 3012 is inserted into the cylindrical cavity 3014, with a spring 3013 positioned between the top of the latch 3012 and the top of the cylindrical cavity 3014. The bottom of the latch 3012 is wedge-shaped, and the side of the hole 3011 near the inside of the perforated steel pipe 3 is inclined. The wedge-shaped portion of the lower portion of the latch 3012 has a vertical outer surface and an inclined inner surface, restricting the buckle 301 from being ejected outward. This also prevents the buckle 301 from slipping out of its initial position within the opening of the perforated steel pipe 3 when the positioning device 4 is not yet inserted. The spring 3013 is pre-compressed initially, so that the latch 3012 is pressed by the spring 3013 to more firmly press against the buckle 301, thereby preventing the latch 3012 from loosening when disturbed and causing the buckle 301 to fall off.

[0052] Before assembly, the lower wedge-shaped body of the pin 3012 extends out of the cylindrical cavity 3014 and is inserted into the socket 3011 reserved at the corresponding position on the outer upper surface of the buckle 301, fixing the buckle 301 in the initial position; during the assembly process, after the smooth inclined surface on the inner side of the buckle 301 contacts the positioning device 4, the pin 3012 is pushed upward along its inclined surface out of the socket 3011 and into the cylindrical cavity 3014, and at the same time, the spring 3013 is forced to contract until the buckle 301 completely pushes the pin 3012 out of the socket 3011, and the bottom of the pin 3012 touches the upper surface of the buckle 301.

[0053] like Figures 3a to 3d As shown, a roller 3015 is provided at the inclined end facing the inside of the perforated steel tube 3. The roller 3015 is embedded in the steel tube 3. The outer surface of the buckle 301 end is smoothly connected to the roller 3015, with only a small portion of the inner end of the buckle 301 exposed. In other words, the roller 3015 does not affect the insertion of the positioning device 4 and the process of pushing the buckle 301 outward. When the positioning device 4 is inserted into the perforated steel tube 3, the outer wall of the positioning device 4 abuts against the roller 3015. When the positioning device 4 moves downward, the roller 3015 rolls on the outer wall of the positioning device 4. This prevents the outer surface of the thin-walled steel tube 402 from gradually increasing in contact with the inner end of the buckle 301 when the positioning device 4 is inserted, thereby preventing the thin-walled steel tube 402 from being inserted more difficultly and the inner end of the buckle 301 from being worn, resulting in insufficient extension length. The gap between the roller 3015 and the buckle 301 is filled with lubricating oil to prevent the roller 3015 from causing excessive friction when rotating and thus causing it to get stuck when contacting the positioning device 4. Lubricating oil is applied between the buckle 301 and the opening of the perforated steel pipe 3 and on the anti-shear ring 102 to prevent the buckle 301 from being unable to reach the predetermined position due to excessive friction when being ejected.

[0054] It should be noted that the parts in this embodiment that are the same or similar to those in the first embodiment can be referenced to each other and will not be described in detail in this application.

[0055] Example 3

[0056] As another embodiment, this embodiment 3 proposes, based on the first and second embodiments, a construction method of such a prefabricated CFST-RC column cross-section conversion node, including the following steps:

[0057] Step 1: Tie the reinforced concrete column 2 reinforcement cage and set the vertical longitudinal reinforcement 201;

[0058] Step 2: transport the perforated steel pipe 3 prefabricated in the factory to the construction site, use a scaffolding or lifting device to insert the lower half of the perforated steel pipe 3 into the pouring area of ​​the reinforced concrete column 2, and weld it to the vertical longitudinal reinforcement 201;

[0059] Step 3: Support the formwork and cast the lower reinforced concrete column 2, cast the lower half of the perforated steel pipe 3 into the lower reinforced concrete column 2, and reserve the grouting channel 501 and the grouting channel 502 extending to the top surface of the reinforced concrete column 2.

[0060] One end of the grouting channel 501 is located on the side wall of the reinforced concrete column 2, and the other end is located on the top surface of the reinforced concrete column 2. The end of the grouting channel 501 located on the top surface of the reinforced concrete column 2 is located outside the perforated steel pipe 3. One end of the grouting channel 502 is opened at the top of the reinforced concrete column 2 inside the perforated steel pipe 3, and the other end is opened on the side wall of the reinforced concrete column 2 below the bottom end of the perforated steel pipe 3.

[0061] Step 4: Install the steel pipe 101 above the reinforced concrete column 2;

[0062] Step 5. Insert the positioning device 4 vertically downward from the top of the steel pipe 101. The positioning device 4 contacts several layers of clips 301 from top to bottom in sequence and pushes the clips 301 outward and inserts them into the corresponding shear ring 102 intervals; the bottom end of the thin-walled steel pipe 402 touches the top surface of the reinforced concrete column 2 cast in step 3, and the assembly is completed.

[0063] Step six: grouting is performed into the cavity between the perforated steel pipe 3 and the steel pipe 101 through the grouting channel 501. When the slurry is stably flowing out of the opening at one end of the slurry outlet channel 502 located on the side of the reinforced concrete column 2, the opening at this end is closed with a baffle or a plug. When the grouting material is poured to the top surface of the steel pipe 101, the upper steel tube concrete column 1 is poured until the curing is completed. After the grouting material solidifies and reaches the predetermined strength, the temporary support during construction is removed to complete the construction of this conversion node.

[0064] Example 4

[0065] As another embodiment, this fourth embodiment proposes, based on the third embodiment, a more specific construction method for a prefabricated CFST-RC column equal-section conversion node:

[0066] In step six, grouting is performed from one end of the grouting channel 501 provided on the side wall of the reinforced concrete column 2. The slurry is injected into the cavity between the perforated steel pipe 3 and the steel pipe 101 from one end of the grouting channel 501 provided on the top surface of the reinforced concrete column 2, squeezing out the internal gas from bottom to top to avoid the existence of bubbles. After the slurry overflows from the top of the cavity between the perforated steel pipe 3 and the steel pipe 101, it enters the interior of the perforated steel pipe 3 and casts the gap between the perforated steel pipe 3 and the positioning device 4 and the interior of the positioning device 4.

[0067] After the slurry enters the perforated steel pipe 3, it flows out of the side wall of the reinforced concrete column 2 through the slurry outlet channel 502. When the slurry flow rate out of the end of the slurry outlet channel 502 opened on the side wall of the reinforced concrete column 2 is uniform, the slurry outlet channel 502 is blocked from the side wall of the reinforced concrete column 2. After pouring is completed, the opening of the grouting channel 501 on the side wall of the reinforced concrete column 2 is also blocked. When the concrete reaches the predetermined strength, the steel tube concrete column 1 and the reinforced concrete column 2 are completely connected together, and the grouting channel 501 and the slurry outlet channel 502 in the reinforced concrete column 2 are also filled with concrete.

[0068] The grouting material should be non-shrinkage high-strength grouting material, which has good self-flowability, small aggregate, good self-compactness, no need for vibration during pouring, and can avoid clogging of the grouting channels; at the same time, it has high strength and can significantly improve the bearing and deformation resistance of the structure.

[0069] After the poured grouting material is hardened and formed, the grouting material between each adjacent row of shear rings 102 can be approximated as a number of short compression columns, which jointly bear the shear force.

[0070] It should be noted that the parts in this embodiment that are the same or similar to those in the third embodiment can be referenced to each other and will not be described in detail in this application.

[0071] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A prefabricated CFST-RC column equal-section conversion node, characterized in that: include: A steel tube concrete column, a reinforced concrete column, a perforated steel pipe and a positioning device, wherein the steel tube concrete column is arranged above the reinforced concrete column, and the perforated steel pipe is inserted at the connection node between the steel tube concrete column and the reinforced concrete column; The lower half of the perforated steel pipe is cast in the reinforced concrete column, and the upper half of the perforated steel pipe is provided with several layers of openings at different heights. The openings in each layer are arranged in a circumferential direction, and a buckle is inserted horizontally in each opening. Several layers of shear rings are provided on the inner wall of the steel tube concrete column corresponding to the openings. When the positioning device is inserted into the perforated steel pipe, the buckle extends from the inside of the opening to the outside of the perforated steel pipe and is inserted between the shear rings. The bottom of the buckle is a flat surface, the top end facing the inside of the perforated steel pipe is a downward inclined surface, the top end facing the outside of the perforated steel pipe is a flat surface, a plug hole is provided on the flat surface, a cylindrical cavity is provided above the perforated steel pipe corresponding to the plug hole, a pin is inserted in the cylindrical cavity, and a spring is provided between the top of the pin and the top of the cylindrical cavity; the bottom end of the pin is wedge-shaped, and the side of the plug hole close to the inside of the perforated steel pipe is an inclined surface; The reinforced concrete column includes vertical longitudinal bars, which are welded to the outer surface of the perforated steel pipe; the positioning device includes a perforated ring and a thin-walled steel pipe, the outer diameter of the thin-walled steel pipe is less than or equal to the inner wall of the perforated steel pipe, the perforated ring is fixed on the top of the thin-walled steel pipe, and the perforated ring is provided with an opening for the vertical longitudinal bars to pass through and the concrete slurry to flow out.

2. The assembled CFST-RC column equal-section conversion node according to claim 1 is characterized in that: A roller is provided at the inclined end facing the inner side of the perforated steel pipe. When the positioning device is inserted into the perforated steel pipe, the outer wall of the positioning device rests on the roller. When the positioning device moves downward, the roller rolls on the outer wall of the positioning device.

3. The construction method of the assembled CFST-RC column equal-section conversion node according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1: Tie the reinforced concrete column reinforcement cage and set the vertical longitudinal reinforcement; Step 2: Insert the lower half of the perforated steel pipe into the reinforced concrete column pouring area and weld it to the vertical longitudinal reinforcement; Step 3: Support the formwork and cast the reinforced concrete column, cast the lower half of the perforated steel pipe into the reinforced concrete column, and reserve a grouting channel extending to the top surface of the reinforced concrete column; Step 4: Install the steel pipe above the reinforced concrete column; Step 5: Insert the positioning device vertically downward from the top of the steel pipe. The positioning device contacts the buckles in layers from top to bottom in sequence and pushes the buckles outward and inserts them into the corresponding shear ring intervals. Step 6: Grout the cavity between the perforated steel pipe and the steel pipe through the grouting channel. The slurry overflows from the top of the positioning device and flows into the perforated steel pipe. The construction of this conversion node is completed after the slurry is poured until it reaches the top surface of the steel pipe.

4. The construction method of the assembled CFST-RC column equal-section conversion node according to claim 3 is characterized in that: One end of the grouting channel is arranged on the side wall of the reinforced concrete column, and the other end is arranged on the top surface of the reinforced concrete column, and the end of the grouting channel arranged on the top surface of the reinforced concrete column is located on the outside of the perforated steel pipe. In step six, grouting is performed from the end of the grouting channel arranged on the side wall of the reinforced concrete column, and the slurry is injected from the end of the grouting channel arranged on the top surface of the reinforced concrete column, and the slurry is injected into the cavity between the perforated steel pipe and the steel pipe. After the slurry overflows from the top of the cavity between the perforated steel pipe and the steel pipe, it enters the interior of the perforated steel pipe, and pours the gap between the perforated steel pipe and the positioning device and the interior of the positioning device.

5. The construction method of the assembled CFST-RC column equal-section conversion node according to claim 4 is characterized in that: In step three, a slurry outlet channel is reserved when the reinforced concrete column is cast. One end of the slurry outlet channel is opened at the top of the reinforced concrete column inside the perforated steel pipe, and the other end is opened at the side wall of the reinforced concrete column below the bottom end of the perforated steel pipe; in step six, the slurry overflows from the top of the cavity between the perforated steel pipe and the steel pipe, enters the inside of the perforated steel pipe, and flows out from the side wall of the reinforced concrete column through the slurry outlet channel. When the flow rate of the slurry flowing out from one end of the slurry outlet channel opened at the side wall of the reinforced concrete column is uniform, the slurry outlet channel is blocked from one end of the side wall of the reinforced concrete column.

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