Assembled steel pipe recycled concrete column-base socket joint structure and construction method

Abstract

This invention relates to the construction and method of a precast steel-tube recycled concrete column-foundation socket joint, belonging to the field of structural engineering technology. It consists of a steel-tube recycled concrete column and a recycled concrete foundation. The seismic safety of the precast joint is ensured by a combination of pre-embedded anchoring steel plates, hook-type anchors, and UHPC grouting socket connections within the recycled concrete foundation. The precast steel-tube recycled concrete column is composed of steel pipes and recycled concrete. The recycled concrete foundation is composed of steel pipe reinforcement devices, hook-type anchors, and foundation reinforcement. The connection between the vertical anchoring steel plates welded to the steel pipes and the hook-type anchors resists the pull-out resistance of the joint area, and the stability of this connection is ensured by steel pipe stiffening ribs between the steel pipes and the vertical anchoring steel plates. The recycled concrete foundation and the pre-embedded steel pipe reinforcement devices within the foundation jointly bear the horizontal load. This invention improves the utilization rate of solid waste while meeting the seismic resistance requirements of medium-to-high seismic intensity zones.

Description

Technical Field

[0001] This invention relates to a column-foundation joint structure, particularly a precast steel pipe recycled concrete column-foundation joint structure and construction method, belonging to the field of structural engineering technology. Background Technology

[0002] New-type industrialized construction has become an inevitable development direction for my country's construction industry. With the acceleration of my country's economic development and urbanization, housing construction is gradually moving towards "new industrialization." Traditional cast-in-place column-foundation joint construction methods have many limitations, such as long construction cycles, large on-site workload, significant environmental impact, and difficulty in flexibly handling complex terrain. Precast column-foundation joints, with their advantages of high-quality construction, rapid assembly, high construction efficiency, minimal environmental impact, controllable costs, and ease of maintenance, are gradually becoming the main choice for modern housing construction. Precast assembled steel-pipe recycled concrete columns can provide higher load-bearing capacity while reducing the use of formwork, making them more suitable for areas with more difficult construction. The grouting material used, UHPC, has high corrosion resistance. Ordinary concrete generates high-cost construction waste disposal and has a significant environmental impact. Using recycled concrete can promote resource recycling, reduce environmental pollution, lower construction costs, and achieve significant economic benefits.

[0003] Located between the Circum-Pacific Seismic Belt and the Eurasian Seismic Belt, my country experiences frequent earthquakes, which significantly impact building structures. Precast joints often suffer from insufficient stiffness and weak load-bearing capacity. These joints are the weakest points in the entire precast steel-tube recycled concrete column-foundation system. Therefore, it is necessary to propose optimized design schemes for precast steel-tube recycled concrete column-foundation joints suitable for high-intensity seismic zones to enhance joint stiffness, load-bearing capacity, and seismic performance, providing a reference for practical engineering projects.

[0004] In the assembly column joint connection technology, the socket connection has advantages such as less on-site work, simple construction procedures, strong adaptability and good stress performance. In the structural design of traditional column-foundation socket joints, most of the longitudinal reinforcement inside the foundation is cut off. In order to meet the seismic performance requirements, the common measure is to deepen the socket depth, thereby enhancing the bending bearing capacity of the structure. Summary of the Invention

[0005] To address the aforementioned deficiencies in the existing technologies, this invention proposes a construction method and structure for a precast steel pipe recycled concrete column-foundation socket joint. This method not only meets the seismic performance requirements of the joint but also offers advantages such as being green and recyclable, corrosion-resistant, easy to construct, having a low socket depth, and high rigidity. It provides a novel solution for the design of precast column-foundation joint connections in the field of building construction engineering.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The prefabricated steel pipe recycled concrete column-foundation socket joint structure consists of a prefabricated steel pipe recycled concrete column and a recycled concrete foundation. The prefabricated steel pipe recycled concrete column is inserted into the socket of the recycled concrete foundation, and the socket is filled with ultra-high performance concrete (UHPC). The precast steel pipe recycled concrete column includes a steel pipe and recycled concrete inside. The recycled concrete foundation includes a steel pipe reinforcement device, hook-type anchor bolts, longitudinal reinforcement bars, and stirrups; the steel pipe reinforcement device includes a pre-embedded horizontal steel plate and a pre-embedded anchoring steel plate. The precast steel pipe recycled concrete column has trapezoidal steel plates arranged in a cross shape welded vertically around its outer wall. Each trapezoidal steel plate consists of two parallel trapezoidal steel plates, which are fixed together by horizontal bolts to a pre-embedded horizontal steel plate. The pre-embedded horizontal steel plate is embedded in a cross shape around the recycled concrete foundation socket and is located below the longitudinal reinforcement and stirrups of the foundation. The pre-embedded anchoring steel plate is also embedded in a cross shape around the recycled concrete foundation socket and is located below the longitudinal reinforcement and stirrups of the foundation. It is welded to the pre-embedded horizontal steel plate to form a T-shape. A ring-shaped anchoring steel plate is welded to the outer edge of the bottom of the steel pipe. The ring-shaped anchoring steel plate has rectangular openings around its perimeter for the horizontal steel plate to pass through during assembly. Multiple steel pipe stiffening ribs are also evenly arranged between adjacent rectangular openings. The steel pipe stiffening ribs are welded together with the ring-shaped anchoring steel plate and the steel pipe. The hook-shaped anchor is embedded in the recycled concrete foundation at the bottom of the recycled concrete foundation slot, and its top passes through the reserved bolt hole of the annular anchor steel plate and is fixed to the annular anchor steel plate with bolts; wherein, the reserved bolt hole is close to and set on both sides of the rectangular opening.

[0008] Furthermore, in each group of trapezoidal steel plates, the horizontal distance between the two trapezoidal steel plates is 15-20mm.

[0009] Furthermore, the bolt holes of the pre-embedded horizontal steel plate near the bearing slot end are at the same height and have the same diameter as the bolt holes of the trapezoidal steel plate.

[0010] Furthermore, the socket within the recycled concrete foundation is also provided with annular stirrups, which wrap around the longitudinal reinforcement of the foundation; the longitudinal reinforcement, the stirrups, and the annular stirrups together constitute the reinforcement cage of the recycled concrete foundation.

[0011] Furthermore, the longitudinal depth of the pre-embedded horizontal steel plate embedded in the recycled concrete foundation is not less than 1 / 3 of the distance from the concrete around the socket to the edge of the recycled concrete foundation; the depth of the lower edge of the pre-embedded horizontal steel plate embedded in the recycled concrete foundation is not less than 1 / 3 of the thickness of the concrete around the socket.

[0012] Furthermore, the length of the annular anchoring steel plate extending into the ultra-high performance concrete (UHPC) is 4 / 5 times the thickness of the UHPC; the depth of the hook-shaped anchor bolt embedded in the recycled concrete foundation is not less than 1 / 3 of the thickness of the concrete at the bottom of the socket, and the distance between its top and the transverse anchoring steel plate is not less than 80mm.

[0013] Furthermore, the upper edge of the pre-embedded anchor steel plate is not lower than the upper edge of the pre-embedded horizontal steel plate, and not higher than the upper foundation longitudinal reinforcement.

[0014] Furthermore, the thickness of the ultra-high performance concrete (UHPC) around the socket is not less than 100 mm, and a grouting layer with a thickness of 10-30 mm is provided at the bottom of the socket.

[0015] Furthermore, the ultra-high performance concrete (UHPC) has a compressive strength of not less than 120 MPa and a tensile strength of not less than 10 MPa.

[0016] The construction method for the above-mentioned assembled steel pipe recycled concrete column-foundation socket joint structure includes the following steps: S1. Process steel pipes, trapezoidal steel plates, steel pipe stiffening ribs and annular anchoring steel plate components in the factory, weld the annular anchoring steel plate to the outside of the bottom of the steel pipe, weld the steel pipe stiffening ribs to the annular anchoring steel plate and the steel pipe, pour recycled concrete, cure the specimens, and complete the production of precast steel pipe recycled concrete columns and their connection with various components. S2. Process the embedded horizontal steel plate and embedded anchor steel plate components in the factory, and weld the embedded horizontal steel plate to the center of the embedded anchor steel plate to form a T-shaped structure, thus completing the fabrication of the steel pipe reinforcement device. S3. On-site binding of the longitudinal reinforcement, stirrups, and annular stirrups in the socket of the recycled concrete foundation. Reserve sockets for placing precast steel pipe recycled concrete columns. Place the factory-made steel pipe reinforcement devices horizontally on the four sides of the socket. The steel pipe reinforcement devices inside the recycled concrete foundation are fixed to the longitudinal reinforcement and stirrups by welding. Make each pre-embedded anchor steel plate parallel to the four side surfaces of the socket. Weld the hook-shaped anchor bolts to the longitudinal reinforcement and stirrups so that they can be aligned with the bolt holes on the annular anchor steel plate. Support the formwork, pour recycled concrete, cure the components, remove the formwork, and complete the construction of the recycled concrete foundation. S4. Transport the precast steel pipe recycled concrete column to the construction site, mix ultra-high performance concrete (UHPC) on site, lay a 10-30mm grout layer on the bottom surface of the recycled concrete foundation slot, place the gaps of the trapezoidal steel plates in the four directions at the bottom of the precast steel pipe recycled concrete column parallel to the pre-embedded horizontal steel plates and move them down to the upper surface of the grout layer, so that the pre-embedded horizontal steel plates pass through the gaps parallel to each other and are aligned with the bolt holes. At the same time, the hook-shaped anchor bolts pass through the bolt holes of the annular anchoring steel plates and fix the precast steel pipe recycled concrete column by bolt connection, thus completing the placement of the precast steel pipe recycled concrete column. S5. Mix ultra-high performance concrete (UHPC) on site and pour UHPC between the side surface of the recycled concrete foundation and the precast steel pipe recycled concrete column, thereby connecting the precast steel pipe recycled concrete column and the recycled concrete foundation into a whole, completing the assembly of the precast steel pipe recycled concrete column and the recycled concrete foundation.

[0017] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art: This invention proposes a prefabricated column-foundation socket joint structure combining pre-embedded anchor steel plates and pre-embedded anchor bolts in the foundation. Horizontally, the pre-embedded anchor steel plates and foundation concrete jointly resist horizontal forces, while vertically, hook-shaped anchor bolts enhance pull-out resistance. This connection method significantly reduces the socket depth while ensuring the joint's seismic performance. Using recycled concrete columns with steel pipes improves the structure's deformation capacity, and UHPC grouting material ensures corrosion resistance in the joint area. Furthermore, this construction method features simple construction procedures, easy precision control, low construction risk, and environmental friendliness. This invention can promote the widespread adoption of prefabricated prefabricated column-foundation socket connection structures in the field of engineering structures, as detailed below: 1. This invention employs the technical means of prefabricating columns in a prefabrication plant. The connection nodes between the prefabricated steel pipe recycled concrete columns and the recycled concrete foundation adopt a socket-type structure. This method is simple in construction and has high construction efficiency. While ensuring project quality, it reduces the socket depth. The prefabricated columns and foundations are made entirely of recycled concrete, which alleviates resource shortages, reduces overall construction costs, reduces carbon emissions and energy consumption, and is conducive to protecting the local ecological environment.

[0018] 2. The direct connection of pre-embedded anchoring steel plates, steel pipes, and foundation reinforcement forms a unified structure, allowing horizontal forces to be shared by the steel pipes and the recycled concrete foundation. This creates a unified load-bearing system, effectively improving joint strength and enhancing the structure's resistance to horizontal loads. The application of this new device strengthens the connection between the column and foundation, thereby improving the seismic resistance of the column-foundation connection joint.

[0019] 3. The connection between the pre-reserved hook-type anchor bolts and the steel pipe can resist the pull-out force in the joint area and reduce the insertion depth. At the same time, the ultra-high performance concrete (UHPC) also ensures the corrosion resistance of each component in the socket, making the connection between the foundation and the column a whole.

[0020] 4. The socket joint structure, which combines pre-embedded anchor steel plates, anchor bolts, and steel-concrete composite, has good overall integrity and, while ensuring the seismic resistance requirements of the joint, has high load-bearing capacity and large stiffness. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the elevation of the invention; Figure 2 This is the present invention. Figure 1 Schematic diagram of AA section; Figure 3 This is the present invention. Figure 1 Schematic diagram of the BB cross section; Figure 4 This is a schematic diagram of the pre-embedded anchoring steel plate and its components according to the present invention; Figure 5 This is a schematic diagram of the prefabricated steel pipe recycled concrete column processing of the present invention; Figure 6 This is a schematic diagram of the processing of the recycled concrete foundation of the present invention, wherein (a) is a schematic diagram of the binding of the reinforcing steel cage; (b) is a schematic diagram of the pre-embedded anchor steel plate; (c) is a schematic diagram of the anchor bolt placement; (d) is a schematic diagram of the placement of the pre-embedded anchor steel plate; and (e) is an overall view of the recycled concrete foundation. Figure 7 This is a three-dimensional schematic diagram of the prefabricated assembled column-foundation of the present invention, wherein (a) is a prefabricated steel pipe recycled concrete column; (b) is a recycled concrete foundation; (c) is a column-foundation socket assembly diagram; and (d) is a schematic diagram of grouting in the socket gap. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-7 The present invention will be further described in detail below to facilitate a clear understanding of the invention, but these descriptions do not constitute a limitation thereof.

[0023] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] As attached Figure 1-5 As shown, the assembled steel pipe recycled concrete column-foundation socket joint structure of this embodiment consists of a precast steel pipe recycled concrete column (1) and a recycled concrete foundation (2). The precast steel pipe recycled concrete column (1) is inserted into the socket of the recycled concrete foundation (2), and the socket is filled with ultra-high performance concrete UHPC (10). like Figure 1-2 As shown, the precast steel pipe recycled concrete column 1 includes a steel pipe 3 and recycled concrete 4 inside.

[0026] like Figure 1 and Figure 3 As shown, the recycled concrete foundation 2 includes a steel pipe reinforcement device 17, hook-type anchor bolts 9, longitudinal reinforcement bars 11, and foundation stirrups 12. The steel pipe reinforcement device 17 includes a pre-embedded horizontal steel plate 6 and a pre-embedded anchoring steel plate 7. A ring stirrup 14 is also provided within the socket of the recycled concrete foundation 2, and the foundation stirrup 12 wraps around the longitudinal reinforcement bars 11. The longitudinal reinforcement bars 11, foundation stirrups 12, and ring stirrups 14 together constitute the reinforcement cage of the recycled concrete foundation 2.

[0027] like Figure 1 As shown, the outer wall of the precast steel pipe recycled concrete column 1 is vertically welded with trapezoidal steel plates arranged in a cross shape. Each trapezoidal steel plate assembly consists of two parallel trapezoidal steel plates 5, with a pre-embedded horizontal steel plate 6 fixed between them by horizontal bolts 15. The pre-embedded horizontal steel plate 6 is pre-embedded in a cross shape around the socket of the recycled concrete foundation 2, located below the longitudinal reinforcement 11 and the foundation stirrups 12. Pre-embedded anchoring steel plates 7 are also pre-embedded in a cross shape around the socket of the recycled concrete foundation 2, located below the longitudinal reinforcement 11 and the foundation stirrups 12, and welded to the pre-embedded horizontal steel plate 6 to form a T-shape, as shown. Figure 4 As shown.

[0028] like Figure 5 As shown, a ring-shaped anchoring steel plate 16 is welded to the outer edge of the bottom of the steel pipe 3. The ring-shaped anchoring steel plate 16 has rectangular openings around its perimeter for the horizontal steel plate 6 to pass through during assembly. Multiple steel pipe stiffening ribs 8 are also evenly arranged between adjacent rectangular openings. The steel pipe stiffening ribs 8 are welded together with the ring-shaped anchoring steel plate 16 and the steel pipe 3.

[0029] like Figure 1 and Figure 3 As shown, the hook-shaped anchor bolt 9 is pre-embedded in the recycled concrete foundation 2 at the bottom of the socket of the recycled concrete foundation 2, and its top passes through the reserved bolt hole of the annular anchor steel plate 16 and is fixed to the annular anchor steel plate 16 by bolts 13. The reserved bolt hole is close to and set on both sides of the rectangular opening.

[0030] In this embodiment, specifically, in each group of trapezoidal steel plates, the horizontal distance between the two trapezoidal steel plates 5 is 15-20mm. The bolt holes of the pre-embedded horizontal steel plate 6 near the socket end are at the same height and have the same diameter as the bolt holes of the trapezoidal steel plate 5. The longitudinal depth of the pre-embedded horizontal steel plate 6 embedded in the recycled concrete foundation 2 is not less than 1 / 3 of the distance from the concrete around the socket to the edge of the recycled concrete foundation 2. The lower edge of the pre-embedded horizontal steel plate 6 is embedded in the recycled concrete foundation 2 to a depth not less than 1 / 3 of the thickness of the concrete around the socket. The length of the annular anchoring steel plate 16 extending into the ultra-high performance concrete UHPC 10 is 4 / 5 times the thickness of the ultra-high performance concrete UHPC 10. The depth of the hook-type anchor bolt 9 embedded in the recycled concrete foundation 2 is not less than 1 / 3 of the thickness of the lower concrete of the socket, and the distance between its top and the horizontal anchoring steel plate 16 is not less than 80mm. The upper edge of the pre-embedded anchoring steel plate 7 is not lower than the upper edge of the pre-embedded horizontal steel plate 6, and not higher than the upper longitudinal reinforcement 11 of the foundation. The thickness of the ultra-high performance concrete UHPC10 around the socket is not less than 100mm, and a grouting layer with a thickness of 10-30mm is provided at the bottom of the socket.

[0031] In this embodiment, the compressive strength of ultra-high performance concrete UHPC10 is not less than 120 MPa, and the tensile strength is not less than 10 MPa.

[0032] Example 2 The construction method of the assembled steel pipe recycled concrete column-foundation socket joint structure in Embodiment 1 above is as follows: Figure 7 As shown, it includes the following steps: S1. Process steel pipe 3, trapezoidal steel plate 5, steel pipe stiffening rib 8 and annular anchoring steel plate 16 in the factory. Weld the annular anchoring steel plate 16 to the bottom outside of the steel pipe 3. Weld the steel pipe stiffening rib 8 to the annular anchoring steel plate 16 and the steel pipe 3. Pour recycled concrete, cure the specimen, and complete the fabrication of the precast steel pipe recycled concrete column 1 and its connection with each component.

[0033] S2. Process the pre-embedded horizontal steel plate 6 and pre-embedded anchor steel plate 7 components in the factory, and weld the pre-embedded horizontal steel plate 6 to the center position of the pre-embedded anchor steel plate 7 to form a T-shaped structure, thus completing the fabrication of the steel pipe reinforcement device 17.

[0034] S3. On-site binding of the longitudinal reinforcement 11, foundation stirrups 12, and annular stirrups 14 within the socket of the recycled concrete foundation 2. A socket for the precast steel pipe recycled concrete column 1 is pre-reserved. Factory-made steel pipe reinforcement devices 17 are horizontally placed on the four sides of the socket. The steel pipe reinforcement devices 17 inside the recycled concrete foundation 2 are welded to the longitudinal reinforcement 11 and foundation stirrups 12, ensuring that each pre-embedded anchor steel plate 7 is parallel to the four side surfaces of the socket. Hook-type anchor bolts 9 are welded to the longitudinal reinforcement 11 and foundation stirrups 12, aligning them with the bolt holes on the annular anchor steel plate 16. Formwork is then supported, recycled concrete is poured, the component is cured, and the formwork is removed, completing the construction of the recycled concrete foundation 2. (Specific details are as follows...) Figure 6 The steps are shown below.

[0035] S4. Transport the precast steel pipe recycled concrete column 1 to the construction site, mix ultra-high performance concrete UHPC10 on site, lay a 10-30mm grout layer on the bottom surface of the recycled concrete foundation 2 socket, place the gaps of the trapezoidal steel plates 5 in the four directions at the bottom of the precast steel pipe recycled concrete column 1 parallel to the pre-embedded horizontal steel plates 6 and move them down to the upper surface of the grout layer, so that the pre-embedded horizontal steel plates 6 pass through the gaps parallel to each other and are aligned with the bolt holes. At the same time, the hook-shaped anchor bolts 9 pass through the bolt holes of the annular anchoring steel plates 16, and fix the precast steel pipe recycled concrete column 1 by bolt connection, thus completing the placement of the precast steel pipe recycled concrete column 1.

[0036] S5. Mix ultra-high performance concrete (UHPC10) on site and pour it between the socket side surface of the recycled concrete foundation 2 and the precast steel pipe recycled concrete column 1, thereby connecting the precast steel pipe recycled concrete column 1 and the recycled concrete foundation 2 into a whole, completing the assembly of the precast steel pipe recycled concrete column 1 and the recycled concrete foundation 2.

[0037] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the structure of the present invention. The arrangement and quantity of the present invention are not limited to this example and can be optimized according to actual engineering conditions. Any modifications, equivalent changes, and decorations made to the above embodiments based on the technical principles of the present invention, without departing from the scope of the present invention, are still within the scope of the present invention.

Claims

1. A precast steel pipe recycled concrete column-foundation socket joint structure, comprising a precast steel pipe recycled concrete column (1) and a recycled concrete foundation (2), wherein the precast steel pipe recycled concrete column (1) is inserted into a socket of the recycled concrete foundation (2), and the socket is filled with ultra-high performance concrete UHPC (10), characterized in that: The precast steel pipe recycled concrete column (1) includes a steel pipe (3) and internal recycled concrete (4). The recycled concrete foundation (2) includes a steel pipe reinforcement device (17), a hook-type anchor bolt (9), longitudinal reinforcement bars (11) and foundation stirrups (12); the steel pipe reinforcement device (17) includes a pre-embedded horizontal steel plate (6) and a pre-embedded anchoring steel plate (7). The precast steel pipe recycled concrete column (1) has trapezoidal steel plates arranged in a cross shape welded vertically around its outer wall. The trapezoidal steel plate group consists of two parallel trapezoidal steel plates (5). The two trapezoidal steel plates (5) are fixed together by horizontal bolts (15) to the embedded horizontal steel plate (6). The embedded horizontal steel plate (6) is embedded in a cross shape around the socket of the recycled concrete foundation (2) and is located below the longitudinal reinforcement (11) and the stirrups (12) of the foundation. The embedded anchoring steel plate (7) is embedded in a cross shape around the socket of the recycled concrete foundation (2) and is located below the longitudinal reinforcement (11) and the stirrups (12) of the foundation. It is welded to the embedded horizontal steel plate (6) to form a T-shape. The bottom outer edge of the steel pipe (3) is welded with an annular anchoring steel plate (16). The annular anchoring steel plate (16) has rectangular openings around its perimeter for the horizontal steel plate (6) to pass through during assembly. Multiple steel pipe stiffening ribs (8) are also evenly arranged between adjacent rectangular openings. The steel pipe stiffening ribs (8) are welded together with the annular anchoring steel plate (16) and the steel pipe (3). The hook-shaped anchor (9) is embedded in the recycled concrete foundation (2) at the bottom of the recycled concrete foundation (2) slot, and its top passes through the reserved bolt hole of the annular anchor plate (16) and is fixed to the annular anchor plate (16) with bolts (13); wherein the reserved bolt hole is close to and set on both sides of the rectangular opening.

2. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: In each group of trapezoidal steel plates, the horizontal distance between the two trapezoidal steel plates (5) is 15-20mm.

3. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The bolt holes of the pre-embedded horizontal steel plate (6) near the bearing slot end are at the same height and have the same diameter as the bolt holes of the trapezoidal steel plate (5).

4. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The recycled concrete foundation (2) is further provided with a ring stirrup (14) in the socket, and the foundation stirrup (12) wraps around the foundation longitudinal steel bar (11); the foundation longitudinal steel bar (11), the foundation stirrup (12) and the ring stirrup (14) together constitute the steel cage of the recycled concrete foundation (2).

5. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The longitudinal depth of the pre-embedded horizontal steel plate (6) embedded in the recycled concrete foundation (2) is not less than 1 / 3 of the distance from the concrete around the socket to the edge of the recycled concrete foundation (2); the depth of the lower edge of the pre-embedded horizontal steel plate (6) embedded in the recycled concrete foundation (2) is not less than 1 / 3 of the thickness of the concrete around the socket.

6. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The length of the annular anchoring steel plate (16) extending into the ultra-high performance concrete UHPC (10) is 4 / 5 times the thickness of the ultra-high performance concrete UHPC (10); the depth of the hook-shaped anchor bolt (9) embedded in the recycled concrete foundation (2) is not less than 1 / 3 of the thickness of the concrete at the bottom of the socket, and the distance between the top of the anchor bolt and the transverse anchoring steel plate (16) is not less than 80mm.

7. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The upper edge of the pre-embedded anchor steel plate (7) is not lower than the upper edge of the pre-embedded horizontal steel plate (6) and not higher than the upper foundation longitudinal reinforcement (11).

8. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The ultra-high performance concrete UHPC (10) has a thickness of not less than 100 mm around the socket, and a grouting layer with a thickness of 10-30 mm is provided at the bottom of the socket.

9. The assembled steel pipe recycled concrete column-foundation socket joint structure according to claim 1, characterized in that: The compressive strength of the ultra-high performance concrete UHPC (10) is not less than 120 MPa and the tensile strength is not less than 10 MPa.

10. A construction method for the assembled steel pipe recycled concrete column-foundation socket joint structure according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Process steel pipe (3), trapezoidal steel plate (5), steel pipe stiffening rib (8) and annular anchoring steel plate (16) components in the factory, weld the annular anchoring steel plate (16) to the bottom outside of the steel pipe (3), weld the steel pipe stiffening rib (8) to the annular anchoring steel plate (16) and the steel pipe (3), pour recycled concrete, cure the specimen, and complete the production of the precast steel pipe recycled concrete column (1) and the connection with each component; S2. Process the pre-embedded horizontal steel plate (6) and pre-embedded anchor steel plate (7) components in the factory, and weld the pre-embedded horizontal steel plate (6) to the center of the pre-embedded anchor steel plate (7) to form a T-shaped structure, and complete the production of the steel pipe reinforcement device (17); S3. Tie the longitudinal reinforcement (11), stirrups (12) and ring stirrups (14) in the socket of the recycled concrete foundation (2) on site. Reserve the socket for the precast steel pipe recycled concrete column (1). Place the steel pipe reinforcement device (17) manufactured in the factory on the four sides of the socket. The steel pipe reinforcement device (17) located inside the recycled concrete foundation (2) is fixed by welding to the longitudinal reinforcement (11) and stirrups (12) of the foundation. Make each pre-embedded anchor steel plate (7) parallel to the four sides of the socket. Weld the hook-type anchor bolt (9) to the longitudinal reinforcement (11) and stirrups (12) of the foundation so that it can be aligned with the bolt holes on the ring anchor steel plate (16). Support the formwork, pour recycled concrete, cure the components, remove the formwork, and complete the construction of the recycled concrete foundation (2). S4. Transport the precast steel pipe recycled concrete column (1) to the construction site, mix ultra-high performance concrete UHPC (10) on site, lay a 10-30mm grout layer on the bottom surface of the recycled concrete foundation (2) slot, place the gaps of the trapezoidal steel plates (5) in the four directions at the bottom of the precast steel pipe recycled concrete column (1) parallel to the embedded horizontal steel plates (6) and move them down to the upper surface of the grout layer, so that the embedded horizontal steel plates (6) pass through the gaps parallel to each other and are aligned with the bolt holes. At the same time, the hook-type anchor bolts (9) pass through the bolt holes of the annular anchor plate (16) and fix the precast steel pipe recycled concrete column (1) by bolt connection, thus completing the placement of the precast steel pipe recycled concrete column (1). S5. Mix ultra-high performance concrete UHPC (10) on site and pour ultra-high performance concrete UHPC (10) between the socket side surface of the recycled concrete foundation (2) and the precast steel pipe recycled concrete column (1), so that the precast steel pipe recycled concrete column (1) and the recycled concrete foundation (2) are connected into a whole, and the assembly work of the precast steel pipe recycled concrete column (1) and the recycled concrete foundation (2) is completed.

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