Composite-concrete-steel double-wall hollow pipe column assembled node and construction method thereof

Abstract

The present invention relates to a composite-concrete-steel double-wall hollow pipe column assembled node, comprising a prefabricated column, a reinforced concrete foundation / cap beam, and a high-strength non-shrinkage mortar layer; the prefabricated column comprises a composite pipe, a steel pipe, and a concrete layer, the composite pipe is sleeved outside the steel pipe, the space between the composite pipe and the steel pipe is filled with concrete to form a concrete layer, and one end of the steel pipe extends from one end of the composite pipe; a metal bellows is embedded in the reinforced concrete foundation / cap beam; the end of the steel pipe extending from the composite pipe is inserted into the metal bellows, and high-strength non-shrinkage mortar is poured between the metal bellows and the steel pipe to form a high-strength non-shrinkage mortar layer. The present invention also relates to a construction method for a composite-concrete-steel double-wall hollow pipe column assembled node. The present invention has the advantages of a clear force transmission path, good ductility, high integrity, excellent seismic performance, and controllable node quality, and belongs to the technical field of combined structure assembled buildings.

Description

Technical Field

[0001] The present invention relates to the technical field of composite structure assembled buildings, and in particular to a composite-concrete-steel double-wall hollow pipe column assembled node and a construction method thereof. Background Art

[0002] Composite materials (composites) refer to new structural materials composed of fiber reinforcement and a resin matrix. Compared to traditional structural materials, they offer advantages such as light weight, high strength, and excellent corrosion resistance. Civil engineering researchers have proposed a new composite structure called a composite-concrete-steel double-wall hollow tubular column. This structure optimizes the combination of concrete, steel, and composite materials, allowing each material to leverage its strengths, resulting in exceptionally superior mechanical properties. Compared to steel-concrete double-wall columns, this new composite structure boasts enhanced corrosion resistance due to the protection of the inner steel tubes by a sandwich concrete layer and an outer composite tube. Furthermore, the inner steel tubes act as longitudinal reinforcement, providing bending resistance. Compared to composite-confined concrete, the hollow interior of this composite structure reduces concrete consumption, resulting in a lighter weight and a smaller cross-sectional dimension. These advantages make composite-concrete-steel double-wall hollow tubular columns particularly suitable for bridge structures operating in corrosive environments (such as marine environments) and requiring seismic resistance.

[0003] If composite-concrete-steel double-wall hollow tube composite columns are to be used in bridges requiring seismic resistance, the connection nodes between the composite piers and other reinforced concrete components, such as the upper cap beam and lower pile bent (or foundation), become crucial, and their reliability is crucial to the safety of the structure. Under earthquake action, these nodes transmit shear forces in the piers and cap beams, with significant shear forces in their core regions, making them prone to shear brittle failure. Unlike the "strong column, weak beam" structure of a building frame, bridge structures rely primarily on the ductility of the piers, not the cap beam, to deform under transverse earthquakes. Ideally, plastic hinges occur at the upper and lower ends of the piers. Bridge nodes are undoubtedly capacity-protecting components and must maintain high strength and stiffness under earthquake action. Furthermore, traditional cast-in-place joints are inefficient to construct, and the quality of cast-in-place concrete is often difficult to guarantee. Therefore, it is crucial to develop prefabricated composite-concrete-steel double-wall hollow tube composite column joints that offer simple construction, clear force transmission, and excellent seismic performance.

[0004] However, current research on this new type of composite column mainly focuses on the axial compression, bending, eccentric compression performance and seismic performance of each part of the composite component itself. Therefore, in the field of composite structure prefabricated building technology, the present invention proposes a composite-concrete-steel double-wall hollow tube column prefabricated node. Summary of the Invention

[0005] In response to the technical problems existing in the prior art, the purpose of the present invention is to provide a composite-concrete-steel double-wall hollow pipe column prefabricated node and its construction method to meet the requirements of reasonable and safe force transmission in beam-column nodes and improve construction efficiency in practical applications.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A composite-concrete-steel double-wall hollow pipe column prefabricated node comprises a prefabricated column, a reinforced concrete foundation / cap beam, and a high-strength non-shrinkage mortar layer; the prefabricated column comprises a composite pipe, a steel pipe, and a concrete layer, the composite pipe being sleeved over the steel pipe, the space between the composite pipe and the steel pipe being filled with concrete to form a concrete layer, and one end of the steel pipe extending from one end of the composite pipe; a metal bellows is embedded in the reinforced concrete foundation / cap beam; the end of the steel pipe extending from the composite pipe is inserted into the metal bellows, and high-strength non-shrinkage mortar is poured between the metal bellows and the steel pipe to form a high-strength non-shrinkage mortar layer.

[0008] As a preferred embodiment, the portion of the steel pipe that is longer than the composite pipe is inserted into the metal corrugated pipe. The length of the insertion is equal to the embedding depth d of the prefabricated column in the reinforced concrete foundation / cap beam, satisfying:

[0009]

[0010] Where:

[0011] V: Design value of the maximum shear force transferred to the node (KN);

[0012] D: inner diameter of prefabricated column composite tube (mm);

[0013] M: Design value of the maximum bending moment transferred to the node (KN·m);

[0014] f c : Design compressive strength of concrete in reinforced concrete foundation / cap beam (MPa).

[0015] As a preferred embodiment, a shear ring is welded to the end of the steel pipe inserted into the metal bellows, and the steel pipe and the shear ring are concentric; the wall thickness of the steel pipe is t, the radial width of the shear ring is 17t, and the width of the shear ring extending to the inside and outside of the steel pipe is 8t.

[0016] As a preferred embodiment, a steel ring plate is welded to the outer wall of the steel pipe for supporting the composite pipe and pouring concrete. The position of the steel ring plate in the axial direction corresponds to the end of the composite pipe, and the outer diameter of the steel ring plate is 5% larger than that of the composite pipe.

[0017] As a preferred embodiment, the steel pipe is inserted into one end of the metal corrugated pipe and filled with concrete to form a concrete section, and the length of the concrete section is ≥ the embedding depth d + the inner diameter of the composite pipe.

[0018] As a preferred embodiment, a mortar layer is provided on the side of the shear ring facing away from the steel pipe; the material of the mortar layer is the same as the high-strength non-shrinkage mortar layer, and the thickness of the mortar layer is 10 to 30 mm.

[0019] A construction method for a composite-concrete-steel double-wall hollow pipe column prefabricated node. The preparation of the prefabricated column includes the following steps: welding end shear rings and a middle steel ring plate to the steel pipe according to design requirements; inserting a composite pipe outside the welded steel pipe, with one end of the composite pipe resting on the steel ring plate, and keeping the steel pipe and the composite pipe aligned; fixing the outer composite pipe; pouring concrete between the steel pipe and the composite pipe, and pouring concrete within a certain height range inside the steel pipe, and curing to form the concrete.

[0020] As a preferred embodiment, the construction of the column foot foundation node includes the following steps: completing the preparation of the prefabricated column and transporting it to the installation site; installing the steel cage on the reinforced concrete foundation, and fixing the metal bellows in the node area, sealing the bottom of the metal bellows with a template, and pouring the foundation concrete; when the strength of the prefabricated column and the foundation concrete reaches 70% of the design strength, removing the sealing template at the bottom of the metal bellows, laying a mortar layer on the concrete surface at the bottom of the metal bellows, inserting the steel pipe of the prefabricated column, placing the shear ring on the mortar layer, adjusting the position of the prefabricated column and fixing it, and then pouring high-strength non-shrinkage mortar between the prefabricated column and the metal bellows to connect the reinforced concrete foundation and the prefabricated column as a whole, completing the construction of the node.

[0021] As a preferred embodiment, the construction of the cap beam node includes the following steps: completing the preparation of prefabricated columns and prefabricated cap beams, the preparation of the prefabricated cap beams includes steel bar binding, installation of metal bellows, reservation of grouting holes and exhaust holes, and pouring of concrete; transporting the prefabricated columns and prefabricated cap beams to the installation site; installing the prefabricated columns at predetermined positions, cleaning the top surfaces of the prefabricated columns, and laying a mortar layer on the top surface; hoisting the prefabricated cap beams to predetermined positions so that the metal bellows are deeply seated on the mortar layer on the top surface of the prefabricated columns; installing a sealing template under the metal bellows to prevent leakage of grouting material during grouting; pouring high-strength non-shrinkage mortar through the grouting holes to connect the prefabricated cap beams and prefabricated columns as a whole, and after solidification, removing temporary measures to complete the installation and fixation of the node.

[0022] As a preferred option, after completing the reinforcement binding of the reinforced concrete foundation / cap beam, fix the metal corrugated pipe in the core area of ​​the node, place a sealing formwork at the bottom of the metal corrugated pipe, pour the foundation / cap beam concrete, cure and shape it, and remove the sealing formwork; the inner diameter of the metal corrugated pipe is 100mm larger than the outer diameter of the composite pipe, and the height of the metal corrugated pipe is equal to the burial depth d + the mortar thickness.

[0023] As a preferred option, for the cap beam node, when installing the metal bellows, grouting holes and exhaust holes for the later pouring of high-strength non-shrinkage mortar are reserved; 4 to 6 reserved holes with a diameter of 12 mm are evenly arranged along the outer circle on the top surface of the embedded metal bellows, 2 of which are used as exhaust holes and the rest are used as grouting holes.

[0024] The present invention has the following advantages:

[0025] 1. The node provided by the present invention can realize the simultaneous construction of prefabricated columns and reinforced concrete foundations / cap beams. In addition to prefabricated columns, reinforced concrete cap beams are also prefabricated, which has simple assembly and high construction efficiency, and can ensure the reliability of construction.

[0026] 2. The node provided by the present invention uses a corrugated pipe with a special concave-convex pipe wall, which can improve the adhesion of concrete poured at different times, thereby improving the bearing capacity of the node and has the advantage of good and clear force transmission.

[0027] 3. The node provided by the present invention pours high-strength non-shrinkage mortar between the end of the prefabricated column and the metal bellows, so that the prefabricated column and the reinforced concrete foundation / cap beam are firmly combined to form a whole, which can significantly improve the integrity, seismic resistance and ductility of the node.

[0028] 4. The composite-concrete-steel double-wall hollow pipe column assembled node of the present invention has the advantages of clear force transmission path, good ductility, high integrity, excellent seismic performance and controllable node quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the composite-concrete-steel double-wall hollow pipe column prefabricated foundation node structure.

[0030] Figure 2 This is a schematic diagram of the composite-concrete-steel double-wall hollow tube column prefabricated cap beam node structure.

[0031] Figure 3 It is a structural diagram of reinforced concrete cap beam (with embedded metal corrugated pipe inside).

[0032] Figure 4 This is a schematic diagram of the prefabricated composite-concrete-steel double-wall hollow pipe column structure.

[0033] Figure 5 It is a schematic diagram of a steel pipe.

[0034] Figure 6 It is a schematic diagram of the shear ring.

[0035] Figure 7 yes Figure 1 Schematic diagram of the AA section.

[0036] Figure 8 yes Figure 1 Schematic diagram of the middle BB cross section.

[0037] Figure 9 yes Figure 1 Schematic diagram of the CC cross section.

[0038] Figure 10 This is a schematic diagram of the installation of a composite-concrete-steel double-wall hollow pipe column prefabricated cap beam node.

[0039] Figure 11 This is a schematic diagram of the installation of composite-concrete-steel double-wall hollow pipe column prefabricated foundation nodes.

[0040] In the figure: 1- composite pipe, 2- steel pipe, 3- concrete layer, 4- steel ring plate, 5- high-strength non-shrinkage mortar layer, 6- metal corrugated pipe, 7- shear ring, 8- reinforced concrete foundation, 9- reinforced concrete cap beam, 10- reserved hole. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to specific implementation methods.

[0042] Example 1

[0043] A composite-concrete-steel double-wall hollow pipe column assembled column base foundation node comprises a prefabricated column, a reinforced concrete foundation, and a high-strength non-shrinkage mortar layer; the prefabricated column comprises a composite pipe, a steel pipe, and a concrete layer, the composite pipe being sleeved over the steel pipe, the space between the composite pipe and the steel pipe being filled with concrete to form a concrete layer, and one end of the steel pipe extending from one end of the composite pipe; a metal corrugated pipe is pre-embedded in the reinforced concrete foundation; the end of the steel pipe extending from the composite pipe is inserted into the metal corrugated pipe, and high-strength non-shrinkage mortar is poured between the metal corrugated pipe and the steel pipe to form a high-strength non-shrinkage mortar layer.

[0044] The portion of the steel pipe that is longer than the composite pipe is inserted into the metal corrugated pipe. The length of the insertion is the embedment depth d of the prefabricated column in the reinforced concrete foundation / cap beam, which satisfies:

[0045]

[0046] Where:

[0047] V: Design value of the maximum shear force transferred to the node (KN);

[0048] D: inner diameter of prefabricated column composite tube (mm);

[0049] M: Design value of the maximum bending moment transferred to the node (KN·m);

[0050] f c : Design compressive strength of concrete in reinforced concrete foundation / cap beam (MPa).

[0051] In this embodiment, V = 195 kN, D = 300 mm, M = 305 kN·m, f c =48Mpa, according to the above formula, d≥0.458m.

[0052] In this embodiment, a shear ring is welded to the end of the steel pipe inserted into the metal bellows, and the steel pipe and the shear ring are concentric; the wall thickness of the steel pipe is t=2mm, and the radial width parameter of the shear ring is preferably 17t, with a specific value of 34mm. The width of the shear ring extending to the inside and outside of the steel pipe is 8t, with a specific value of 16mm.

[0053] In this embodiment, a steel ring plate is welded to the outer wall of the steel pipe for supporting the composite pipe and pouring concrete. The position of the steel ring plate in the axial direction corresponds to the end of the composite pipe. The outer diameter parameter of the steel ring plate is preferably 5% larger than the outer diameter of the composite pipe, specifically 15 mm.

[0054] In this embodiment, the steel pipe is inserted into one end of the metal corrugated pipe and filled with concrete to form a concrete section. The length of the concrete section is ≥ the embedment depth d + the inner diameter of the composite pipe. The specific value of the length of the concrete section in this embodiment is 760 mm.

[0055] A mortar layer is set on the side of the shear ring facing away from the metal bellows. The material of the mortar layer is the same as the high-strength non-shrinkage mortar layer, and the thickness of the mortar layer is 10-30 mm. In this embodiment, M80 high-strength non-shrinkage mortar is used, and the thickness of the mortar layer is selected to be 20 mm.

[0056] A construction method for a composite-concrete-steel double-wall hollow pipe column prefabricated column base foundation node. The preparation of the prefabricated column includes the following steps: welding end shear rings and a middle steel ring plate to the steel pipe according to design requirements; inserting a composite pipe outside the welded steel pipe, with one end of the composite pipe resting on the steel ring plate, and keeping the steel pipe and the composite pipe aligned; fixing the outer composite pipe using the existing fixing method; pouring concrete between the steel pipe and the composite pipe, and pouring concrete within a certain height range inside the steel pipe, and curing to form it.

[0057] The construction of the column foot foundation node includes the following steps: completing the preparation of the prefabricated column and transporting it to the installation site; installing the steel cage on the reinforced concrete foundation, and fixing the metal bellows in the node area, sealing the bottom of the metal bellows with a template, and pouring the foundation concrete; when the strength of the prefabricated column and foundation concrete reaches 70% of the design strength, remove the sealing template at the bottom of the metal bellows, lay a mortar layer on the concrete surface at the bottom of the metal bellows, insert the steel pipe of the prefabricated column, place the shear ring on the mortar layer, adjust the position of the prefabricated column and fix it, and then pour high-strength non-shrinkage mortar between the prefabricated column and the metal bellows to connect the reinforced concrete foundation and the prefabricated column as a whole, completing the construction of the node.

[0058] After completing the steel bar binding of the reinforced concrete foundation, fix the metal corrugated pipe in the core area of ​​the node, place the sealing formwork at the bottom of the metal corrugated pipe, pour the foundation concrete, cure and form it, and remove the sealing formwork; the inner diameter of the metal corrugated pipe is 100mm larger than the outer diameter of the composite pipe, and the height of the metal corrugated pipe is equal to the burial depth d + the mortar thickness.

[0059] Example 2

[0060] A composite-concrete-steel double-wall hollow pipe column assembled cap beam node includes a prefabricated column, a reinforced concrete cap beam, and a high-strength non-shrinkage mortar layer; the prefabricated column includes a composite pipe, a steel pipe, and a concrete layer, the composite pipe is sleeved outside the steel pipe, and concrete is filled between the composite pipe and the steel pipe to form a concrete layer, and one end of the steel pipe extends from one end of the composite pipe; a metal corrugated pipe is embedded in the reinforced concrete cap beam; the end of the steel pipe extending from the composite pipe is inserted into the metal corrugated pipe, and high-strength non-shrinkage mortar is poured between the metal corrugated pipe and the steel pipe to form a high-strength non-shrinkage mortar layer.

[0061] The portion of the steel pipe that is longer than the composite pipe is inserted into the metal corrugated pipe. The length of the insertion is the embedment depth d of the prefabricated column in the reinforced concrete foundation / cap beam, which satisfies:

[0062]

[0063] Where:

[0064] V: Design value of the maximum shear force transferred to the node (KN);

[0065] D: inner diameter of prefabricated column composite tube (mm);

[0066] M: Design value of the maximum bending moment transferred to the node (KN·m);

[0067] f c : Design compressive strength of concrete in reinforced concrete foundation / cap beam (MPa).

[0068] In this embodiment, V = 195 kN, D = 300 mm, M = 305 kN·m, f c =48Mpa, according to the above formula, d≥0.458m.

[0069] In this embodiment, a shear ring is welded to the end of the steel pipe inserted into the metal bellows, and the steel pipe and the shear ring are concentric; the wall thickness of the steel pipe is t=2mm, and the radial width parameter of the shear ring is preferably 17t, with a specific value of 34mm. The width of the shear ring extending to the inside and outside of the steel pipe is 8t, with a specific value of 16mm.

[0070] In this embodiment, a steel ring plate is welded to the outer wall of the steel pipe for supporting the composite pipe and pouring concrete. The position of the steel ring plate in the axial direction corresponds to the end of the composite pipe. The outer diameter parameter of the steel ring plate is preferably 5% larger than the outer diameter of the composite pipe, specifically 15 mm.

[0071] In this embodiment, the steel pipe is inserted into one end of the metal corrugated pipe and filled with concrete to form a concrete section. The length of the concrete section is ≥ the embedment depth d + the inner diameter of the composite pipe. The specific value of the length of the concrete section in this embodiment is 760 mm.

[0072] A mortar layer is set on the side of the shear ring facing away from the metal bellows. The material of the mortar layer is the same as the high-strength non-shrinkage mortar layer, and the thickness of the mortar layer is 10-30 mm. In this embodiment, M80 high-strength non-shrinkage mortar is used, and the thickness of the mortar layer is selected to be 20 mm.

[0073] A construction method for a composite-concrete-steel double-wall hollow pipe column prefabricated cap beam node, wherein the preparation of the prefabricated column includes the following steps: welding end shear rings and a middle steel ring plate to the steel pipe according to design requirements; inserting a composite pipe outside the welded steel pipe, with one end of the composite pipe resting on the steel ring plate, and keeping the steel pipe and the composite pipe aligned; fixing the outer composite pipe using the existing fixing method; pouring concrete between the steel pipe and the composite pipe, and pouring concrete within a certain height range inside the steel pipe, and curing to form the concrete.

[0074] The construction of the cap beam node includes the following steps: completing the preparation of prefabricated columns and prefabricated cap beams, the preparation of prefabricated cap beams includes steel bar binding, installation of metal bellows, reservation of grouting holes and exhaust holes, and pouring of concrete; transporting the prefabricated columns and prefabricated cap beams to the installation site; installing the prefabricated columns at the predetermined positions, cleaning the top surfaces of the prefabricated columns, and laying a mortar layer on the top surfaces; hoisting the prefabricated cap beams to the predetermined positions so that the metal bellows are deeply seated on the mortar layer on the top surfaces of the prefabricated columns; installing a sealing template under the metal bellows to prevent leakage of grouting material during grouting; pouring high-strength non-shrinkage mortar through the grouting holes to connect the prefabricated cap beams and prefabricated columns as a whole, and after solidification, removing the temporary measures to complete the installation and fixation of the node.

[0075] After the reinforced concrete cap beam reinforcement is tied, a metal corrugated pipe is fixed to the core area of ​​the node. A sealed formwork is placed at the bottom of the metal corrugated pipe, the cap beam concrete is poured, cured and formed, and the sealed formwork is removed. The inner diameter of the metal corrugated pipe is 100mm larger than the outer diameter of the composite pipe, and the height of the metal corrugated pipe is equal to the embedment depth d + the mortar thickness. For the cap beam node, when the metal corrugated pipe is installed, grouting holes and vents for the later pouring of high-strength, non-shrinkage mortar are reserved. Four to six reserved holes with a diameter of 12mm are evenly arranged along the outer circle of the top surface of the embedded metal corrugated pipe, two of which serve as vents and the remaining as grouting holes.

[0076] In summary, a composite-concrete-steel double-wall hollow tube column prefabricated node meets the requirements of reasonable and safe force transmission in beam-column nodes, and realizes the simultaneous production of columns and reinforced concrete foundations / cap beams, thereby improving construction efficiency in practical applications, eliminating the need for on-site welding, and facilitating easy transportation and assembly.

[0077] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A composite-concrete-steel double-wall hollow pipe column assembled node, characterized by: It includes precast columns, reinforced concrete foundations / cap beams, and high-strength, non-shrinkage mortar layers. The precast columns consist of composite tubes, steel pipes, and concrete layers. The composite tubes are sheathed over the steel pipes, and concrete is filled between the composite tubes and the steel pipes to form a concrete layer. One end of the steel pipe extends from one end of the composite tube. A metal corrugated tube is embedded in the reinforced concrete foundation / cap beam. The end of the steel pipe extending from the composite tube is inserted into the metal corrugated tube, and high-strength, non-shrinkage mortar is poured between the metal corrugated tube and the steel pipe to form a high-strength, non-shrinkage mortar layer. The portion of the steel pipe that is longer than the composite pipe is inserted into the metal corrugated pipe. The length of the insertion is the embedment depth d of the prefabricated column in the reinforced concrete foundation / cap beam, which satisfies: Where: V: Design value of the maximum shear force transferred to the node (KN); D: inner diameter of prefabricated column composite tube (mm); M: Design value of the maximum bending moment transferred to the node (KN·m); f c : Compressive design strength of concrete in reinforced concrete foundation / cap beam (MPa); A shear ring is welded to the end of the steel pipe inserted into the metal bellows, and the steel pipe and the shear ring are concentric; The outer wall of the steel pipe is welded with a steel ring plate for supporting the composite pipe and pouring concrete. The position of the steel ring plate in the axial direction corresponds to the end of the composite pipe.

2. A composite-concrete-steel double-wall hollow pipe column assembled node according to claim 1, characterized in that: The wall thickness of the steel pipe is t, the radial width of the shear ring is 17t, and the width of the shear ring extending to the inside and outside of the steel pipe is 8t.

3. A composite-concrete-steel double-wall hollow pipe column assembled node according to claim 1, characterized in that: The outer diameter of the steel ring plate is 5% larger than the outer diameter of the composite pipe.

4. The composite-concrete-steel double-wall hollow pipe column assembled node according to claim 1, characterized in that: The steel pipe is inserted into one end of the metal corrugated pipe and filled with concrete to form a concrete section. The length of the concrete section is ≥ the embedment depth d + the inner diameter of the composite pipe.

5. The composite-concrete-steel double-wall hollow pipe column assembled node according to claim 2, characterized in that: A mortar layer is set on the side of the shear ring facing away from the steel pipe; the material of the mortar layer is the same as the high-strength non-shrinkage mortar layer, and the thickness of the mortar layer is 10 to 30 mm.

6. A construction method for a composite-concrete-steel double-wall hollow pipe column prefabricated node according to any one of claims 1 to 5, characterized in that: The preparation of prefabricated columns includes the following steps: welding end shear rings and a central steel ring plate to the steel pipe according to design requirements; inserting a composite tube into the welded steel pipe, with one end of the composite tube resting on the steel ring plate, and keeping the steel pipe and the composite tube aligned; fixing the outer composite tube; pouring concrete between the steel pipe and the composite tube, and pouring concrete within a certain height range inside the steel pipe, and curing to form it.

7. The construction method of a composite-concrete-steel double-wall hollow pipe column prefabricated node according to claim 6, characterized in that: The construction of the column foot foundation node includes the following steps: preparing the precast column and transporting it to the installation site; installing the steel cage in the reinforced concrete foundation, fixing the metal bellows in the node area, sealing the bottom of the metal bellows with a template, and pouring the foundation concrete; when the strength of the precast column and foundation concrete reaches 70% of the design strength, removing the sealing template at the bottom of the metal bellows, laying a mortar layer on the concrete surface at the bottom of the metal bellows, inserting the steel pipe of the precast column, placing the shear ring on the mortar layer, adjusting the position of the precast column and fixing it, and then pouring high-strength non-shrinkage mortar between the precast column and the metal bellows to connect the reinforced concrete foundation and the precast column as a whole, completing the construction of the node; The construction of the cap beam node includes the following steps: completing the preparation of prefabricated columns and prefabricated cap beams, the preparation of prefabricated cap beams includes steel bar binding, installation of metal bellows, reservation of grouting holes and exhaust holes, and pouring of concrete; transporting the prefabricated columns and prefabricated cap beams to the installation site; installing the prefabricated columns at the predetermined positions, cleaning the top surfaces of the prefabricated columns, and laying a mortar layer on the top surfaces; hoisting the prefabricated cap beams to the predetermined positions so that the metal bellows are deeply seated on the mortar layer on the top surfaces of the prefabricated columns; installing a sealing template under the metal bellows to prevent leakage of grouting material during grouting; pouring high-strength non-shrinkage mortar through the grouting holes to connect the prefabricated cap beams and prefabricated columns as a whole, and after solidification, removing the temporary measures to complete the installation and fixation of the node.

8. The construction method of a composite-concrete-steel double-wall hollow pipe column prefabricated node according to claim 7, characterized in that: After completing the reinforcement binding of the reinforced concrete foundation / cap beam, fix the metal corrugated pipe in the core area of ​​the node, place the sealing formwork at the bottom of the metal corrugated pipe, pour the foundation / cap beam concrete, cure and form it, and remove the sealing formwork; the inner diameter of the metal corrugated pipe is 100mm larger than the outer diameter of the composite pipe, and the height of the metal corrugated pipe is equal to the burial depth d + the mortar thickness.

9. The construction method of a composite-concrete-steel double-wall hollow pipe column prefabricated node according to claim 7, characterized in that: For the cap beam node, when installing the metal corrugated pipe, grouting holes and exhaust holes for the later pouring of high-strength non-shrinkage mortar should be reserved; 4 to 6 reserved holes with a diameter of 12 mm should be evenly set along the outer circle on the top surface of the embedded metal corrugated pipe, 2 of which are used as exhaust holes and the rest are used as grouting holes.

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