Fabricated connecting joint of existing reinforced concrete column and newly-added steel beam and construction method of fabricated connecting joint

Abstract

The invention discloses a fabricated connection node of an existing reinforced concrete column and a newly-added steel beam, which comprises four steel end plates mounted around the existing reinforced concrete column through anti-shearing pieces, the steel end plates are connected through transverse connecting pieces and first high-strength bolts, and a cantilever beam is welded on each steel end plate; in addition, the invention further provides a construction method of the fabricated connection joint of the existing reinforced concrete column and the newly-added steel beam, and the fabricated connection joint connected with the newly-added steel beam is installed on the existing reinforced concrete column. By means of the modular design, the steel beam and concrete column assembly type connecting structure meets the reinforcement and transformation requirements of steel beams and concrete columns of different specifications and types, the construction efficiency is remarkably improved, the complexity of field welding operation is effectively reduced, the stress performance of assembly type connecting joints is excellent, the anti-seismic ductility is improved, and the construction cost is reduced. The method is suitable for anti-seismic reinforcement and function transformation projects of existing structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of building structure component connection, and specifically relates to an assembled connection node between an existing reinforced concrete column and a newly added steel beam and a construction method thereof. Background Art

[0002] Strengthening and renovating existing buildings is one of the effective ways to improve the overall performance of the structure, extend its service life and enhance its earthquake resistance. In particular, steel structures and steel-concrete composite structures are widely used in the field of building reinforcement due to their light weight, simple construction, superior earthquake resistance and high degree of industrialization. At the same time, traditional reinforced concrete structures are still suitable for columns that mainly bear vertical forces due to their superior compressive properties. Therefore, in modern building reinforcement and renovation, steel structures or composite structures are often used to partially replace the floor system. On the premise of retaining the existing reinforced concrete columns, steel beams are added to enhance the structural performance. However, how to reliably connect the newly added steel beams to the existing reinforced concrete columns has become a key technical problem in the design of such renovations.

[0003] Traditional connection methods usually use technologies such as outer steel plates plus tension bolts or embedded steel bars. This type of method is complex to construct, and requires a large number of holes to be opened or chiseled out of the existing concrete structure, which can easily damage the concrete in the core area. Especially during the welding process, local high temperatures may cause the concrete surface to peel off, reduce strength, and even crack, which seriously affects the seismic performance of the node and the durability of the overall structure. In addition, traditional connection methods often cannot guarantee long-term stability due to uneven force transmission at the nodes.

[0004] Therefore, there is a need for an assembled connection node between an existing reinforced concrete column and a newly added steel beam and a construction method thereof. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an assembled connection node between an existing reinforced concrete column and a newly added steel beam in view of the deficiencies of the above-mentioned prior art. The assembled connection node is formed by fixing four steel end plates around the existing reinforced concrete column, and a cantilever beam is welded on the steel end plates by full penetration, and the steel beam is connected by second high-strength bolts and mounting plate bolt welding. The connection steps of the steel beam and the reinforced concrete column are modularly designed to meet the reinforcement and renovation requirements of steel beams and concrete columns of different specifications and types, significantly improve the construction efficiency, enhance the seismic ductility, and are suitable for seismic reinforcement and functional renovation projects of existing structures.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: an assembled connection node between an existing reinforced concrete column and a newly added steel beam, characterized in that the assembled connection node includes four steel end plates fixedly installed around the existing reinforced concrete column, the steel end plates are connected to the existing reinforced concrete column through multiple shear members welded on the surface of the steel end plates, adjacent steel end plates are connected to each other through multiple transverse connecting members and multiple first high-strength bolts, the connection between the steel end plates and the existing reinforced concrete column and between adjacent steel end plates are filled with post-cast concrete, a cantilever beam is welded on each of the steel end plates through full penetration, and the other end of the cantilever beam is connected to the steel beam through a second high-strength bolt and a mounting plate bolt welding.

[0007] The above-mentioned assembled connection node between the existing reinforced concrete column and the newly added steel beam is characterized in that the thickness of the steel end plate and the thickness of the web of the steel beam are both 10 mm to 20 mm.

[0008] The above-mentioned assembled connection node between an existing reinforced concrete column and a newly added steel beam is characterized in that the shear member is a steel plate with a thickness of 8mm to 20mm and a length of 50mm to 150mm, and a plurality of the shear members are distributed in an array on the steel end plate, with one arranged at every 140mm to 160mm in the longitudinal direction and one arranged at every 80mm to 120mm in the transverse direction.

[0009] The above-mentioned assembled connection node between an existing reinforced concrete column and a newly added steel beam is characterized in that the transverse connector includes a transverse trapezoidal connecting plate, and top plates are vertically welded at both ends of the connecting plate. The connecting plate and the top plate are both made of steel plates or steel sections, and their thickness is 8mm~16mm, the length is 50mm~150mm, and the width is 50mm~100mm. Multiple transverse connectors are arranged at intervals of 140mm~160mm, the number of multiple transverse connectors is more than two, and the horizontal heights of the two transverse connectors are respectively the same as the horizontal heights of the upper flange and the lower flange of the steel beam, and more than two first high-strength bolts are arranged on each top plate of the transverse connector.

[0010] The above-mentioned assembled connection node between an existing reinforced concrete column and a newly added steel beam is characterized in that the diameter of the first high-strength bolt is 16 mm to 22 mm, and the material is high-strength alloy steel with a yield strength exceeding 1000 MPa.

[0011] The above-mentioned assembled connection node between the existing reinforced concrete column and the newly added steel beam is characterized in that the strength grade of the post-cast concrete is one level higher than the concrete strength grade used in the existing reinforced concrete column.

[0012] The above-mentioned assembled connection node between the existing reinforced concrete column and the newly added steel beam is characterized in that the end where the cantilever beam is connected to the steel end plate is precisely cut and polished with an error control within 2 mm.

[0013] The above-mentioned assembled connection node between the existing reinforced concrete column and the newly added steel beam is characterized in that the connection between the existing reinforced concrete column and the steel end plate is roughened to a depth of 30mm to 50mm.

[0014] The above-mentioned assembled connection node between an existing reinforced concrete column and a newly added steel beam is characterized in that the cross-sectional size of the area surrounded by the steel end plates fixedly installed around the existing reinforced concrete column is larger than the cross-sectional size of the existing reinforced concrete column.

[0015] In addition, the present invention also provides a construction method for an assembled connection node between an existing reinforced concrete column and a newly added steel beam, characterized in that the method comprises the following steps:

[0016] Step 1: roughening the area of ​​the existing reinforced concrete column where the steel end plate is to be installed to obtain a roughened existing reinforced concrete column;

[0017] Step 2: Cut, grind and clean the end of the cantilever beam, and then connect the cleaned cantilever beam to the end of the steel end plate without the shear member by full penetration welding to obtain 4 connected cantilever beams and steel end plates;

[0018] Step 3, assembling the four connected cantilever beams and steel end plates obtained in step 2 and the roughened existing reinforced concrete column obtained in step 1, and inserting the shear members of the steel end plates into the roughened existing reinforced concrete column to obtain the roughened existing reinforced concrete column with the cantilever beams and steel end plates installed;

[0019] Step 4: Connect the adjacent steel end plates in the roughened existing reinforced concrete column for installing the cantilever beam and the steel end plate obtained in step 3 by using the first high-strength bolts and transverse connectors to obtain a pre-fixed assembly;

[0020] Step 5: Cast the area between the steel end plate and the roughened existing reinforced concrete column in the pre-fixed assembly obtained in step 4 and the connection between adjacent steel end plates with post-cast concrete, and then perform maintenance to obtain an assembled connection node between the existing reinforced concrete column and the newly added steel beam.

[0021] The present invention increases the bonding force between new and old concrete by roughening, and provides sufficient space for the subsequent embedding of shear members. During construction, professional roughening equipment should be used to ensure that the treated area is evenly covered, and excessive chiseling or local penetration is not caused, so as to avoid damage to the original structure; the shear members on the surface of the steel end plate are deeply embedded in the existing reinforced concrete column after the roughening treatment, so as to enhance the shear resistance of the assembled connection node. During installation, the shear member arrangement position should be accurate to avoid deviation or excessive embedding, so as to ensure the close combination of the shear member and the existing reinforced concrete column when the subsequent concrete is poured, so as to improve the overall force-bearing performance of the assembled connection node; the end of the cantilever beam is cut, polished and cleaned to ensure the flatness and cleanliness of the welding surface, and to avoid impurities affecting the welding quality; the full penetration welding process must be carried out strictly in accordance with the welding process requirements to ensure the strength and uniformity of the weld; after the full penetration welding is completed, the weld should be quality inspected to ensure that there are no defects such as cracks and pores, and the welding meets the design specification requirements; by using tools such as torque wrenches to carry out horizontal The connectors, the first high-strength bolts and the adjacent steel end plates are tightened evenly to avoid local stress concentration or loosening, and to ensure the overall stiffness and strength of the prefabricated connection node connection; through post-poured concrete construction, impurities and dust in the node area should be cleaned before construction to ensure full bonding of the concrete. During the pouring process, a vibrator should be used for uniform vibration to ensure that the post-poured concrete is dense and free of bubbles. The post-poured concrete completely wraps the shear members and steel end plates to improve the overall strength and durability of the prefabricated connection node area; through maintenance, and the controlled maintenance time is 28 days, during which the concrete surface should be kept moist to prevent cracks caused by drying, and measures such as covering with wet straw mats or plastic films are used for maintenance. Water can be sprayed when necessary. The purpose of maintenance is to ensure that the concrete meets the design strength and performance requirements, improve the durability and seismic performance of the prefabricated connection nodes, and ensure the safety and stability of the overall structure. During pouring, it is necessary to ensure full bonding between the post-poured concrete and the existing reinforced concrete columns and steel end plates to avoid gaps or incomplete bonding between the interfaces.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention fixes and installs four steel end plates around the existing reinforced concrete columns, and cantilever beams are welded on the steel end plates by full penetration welding, and the steel beams are connected by second high-strength bolts and mounting plate bolt welding to form an assembled connection node. The connection steps of the steel beams and the reinforced concrete columns are modularly designed to meet the reinforcement and transformation needs of steel beams and concrete columns of different specifications and types. The present invention has strong applicability, significantly improves construction efficiency, and effectively reduces the complexity of on-site welding operations. The assembled connection nodes have excellent force-bearing performance and reliable force transmission. The outer steel end plates effectively constrain the existing reinforced concrete columns in the core area, thereby improving the seismic ductility. The present invention is suitable for seismic reinforcement and functional transformation projects of existing structures.

[0024] 2. The present invention connects adjacent steel end plates with multiple transverse connectors and multiple first high-strength bolts to ensure the structural integrity and material properties of the concrete column, improves the safety and stability of the node connection, and avoids the adverse effects of the high temperature generated during high-temperature welding on the concrete, resulting in a reduction in the local strength of the concrete or the generation of cracks.

[0025] 3. The present invention adopts steel end plates, shear members and transverse connectors and post-cast concrete to achieve rigid connection of nodes. The steel beams are connected by second high-strength bolts and mounting plate bolt welding to ensure effective force transmission between the steel beams and the existing reinforced concrete columns, significantly enhance the overall rigidity of the assembled connection nodes, effectively improve the seismic performance of the building structure, reduce the displacement and deformation of the structure during an earthquake, and ensure the overall stability of the building.

[0026] 4. The prefabricated connection node design of the present invention can adapt to the reinforcement and renovation needs of steel beams of different specifications and types and existing reinforced concrete columns, and has strong applicability. Compared with traditional welding reinforcement methods, the prefabricated connection method is more flexible and avoids the inconvenience and risks brought by on-site welding. It is particularly suitable for renovation projects of complex building structures. This design not only improves the construction quality, but also ensures the long-term performance of the building after renovation.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the connection relationship between the assembled connection nodes of the existing reinforced concrete columns and the newly added steel beams of the present invention.

[0029] Figure 2 Schematic diagram of the connection relationship between the assembled connection node of the existing reinforced concrete column and the newly added steel beam in the present invention from a top view

[0030] Figure 3 Schematic diagram of the connection relationship between the existing reinforced concrete column and the newly added steel beam in the present invention

[0031] Figure 4 It is a schematic diagram of the connection relationship between the steel end plate, the transverse connecting member, the cantilever beam and the steel beam of the present invention.

[0032] Figure 5 It is a schematic diagram of the connection relationship between the existing reinforced concrete column, the steel end plate and the post-cast concrete of the present invention.

[0033] Figure 6 It is a schematic diagram of the connection relationship between the transverse connecting member and the first high-strength bolt of the present invention.

[0034] Description of reference numerals:

[0035] 1—Existing reinforced concrete column; 2—Steel end plate; 3—Shear member;

[0036] 4—Horizontal connector; 4-1—Connecting plate; 4-2—Top plate;

[0037] 5—first high-strength bolt; 6—post-cast concrete; 7—cantilever beam;

[0038] 8—Second high-strength bolt; 9—Mounting plate; 10—Steel beam. DETAILED DESCRIPTION

[0039] An assembled connection node between an existing reinforced concrete column and a newly added steel beam of the present invention is described in detail through Example 1.

[0040] Example 1

[0041] like Figure 1 to Figure 6 As shown, the assembled connection node between the existing reinforced concrete column and the newly added steel beam in this embodiment includes four steel end plates 2 fixedly installed around the existing reinforced concrete column 1, and the steel end plates 2 are connected to the existing reinforced concrete column 1 through multiple shear members 3 welded on the surface of the steel end plates 2, and the adjacent steel end plates 2 are connected to each other through multiple transverse connectors 4 and multiple first high-strength bolts 5, and the connection between the steel end plates 2 and the existing reinforced concrete column 1 and between adjacent steel end plates 2 are filled with post-cast concrete 6, and a cantilever beam 7 is welded on each of the steel end plates 2 through full penetration welding, and the other end of the cantilever beam 7 is bolt-welded to the steel beam 10 through a second high-strength bolt 8 and a mounting plate 9.

[0042] It should be noted that, by fixing four steel end plates 2 around the existing reinforced concrete column 1, and welding a cantilever beam 7 on the steel end plate 2 through full penetration, the steel beam 10 is connected by bolt welding through a second high-strength bolt 8 and a mounting plate 9, to form an assembled connection node, and the connection steps of the steel beam 10 and the reinforced concrete column are modularly designed to meet the reinforcement and renovation needs of steel beams and concrete columns of different specifications and types. It has strong applicability, significantly improves construction efficiency, and effectively reduces the complexity of on-site welding operations. The assembled connection node has excellent force-bearing performance and reliable force transmission. The outer steel end plate 2 plays an effective restraining role on the existing reinforced concrete column 1 in the core area, improves the seismic ductility, and is suitable for seismic reinforcement and functional renovation projects of existing structures.

[0043] It should be noted that the steel end plate 2 further strengthens its connection with the existing reinforced concrete column 1 by welding the shear-resistant member 3, thereby improving the seismic resistance and durability of the assembled connection node.

[0044] It should be noted that the adjacent steel end plates 2 are connected to each other through multiple transverse connectors 4 and multiple first high-strength bolts 5, which avoids high-temperature welding, ensures the structural integrity and material properties of the existing reinforced concrete column 1, and improves the safety and stability of the prefabricated connection node connection.

[0045] It should be noted that the rigid connection of the node is achieved by adopting the steel end plate 2, the shear member 3 and the transverse connector 4, which is fastened by the first high-strength bolt 5 and the first high-strength bolt 5 to ensure the effective force transmission between the steel beam 10 and the existing reinforced concrete column 1, and significantly enhance the overall rigidity of the assembled connection node. Compared with the traditional hinge, it can effectively improve the seismic performance of the building structure, reduce the displacement and deformation of the structure during an earthquake, and ensure the overall stability of the building.

[0046] It should be noted that the connection between the steel end plate 2 and the existing reinforced concrete column 1 and the connection between adjacent steel end plates 2 are filled with post-cast concrete 6 to ensure the close combination of the steel end plate 2 and the existing reinforced concrete column 1 to form an integral structure, enhance the bearing capacity of the prefabricated connection node, and ensure the effective force transmission between the steel beam 10 and the existing reinforced concrete column 1, which is suitable for structural reinforcement and seismic retrofitting projects.

[0047] In this embodiment, the thickness of the steel end plate 2 and the thickness of the web of the steel beam 10 are both 10 mm to 20 mm. By controlling the thickness of the steel end plate 2 and the thickness of the web of the steel beam 10, the size of the steel end plate 2 is adapted to the cross section of the steel beam 10, and the width of the existing reinforced concrete column 1 is taken into consideration to ensure the bearing capacity of the formed assembled connection node and the reliability of the force transmission path.

[0048] It should be noted that the thickness of the steel end plate 2 and the thickness of the web of the steel beam 10 are preferably 10 mm, 15 mm or 20 mm.

[0049] like Figure 4 As shown, in this embodiment, the shear member 3 is a steel plate with a thickness of 8mm to 20mm and a length of 50mm to 150mm. A plurality of the shear members 3 are distributed in an array on the steel end plate 2, with one arranged at every 140mm to 160mm in the longitudinal direction and one arranged at every 80mm to 120mm in the transverse direction. By controlling the parameters and distribution of the shear member 3, it is ensured that the shear member 3 can penetrate into the existing reinforced concrete column 1 after roughening, ensuring the shear force transmission between the steel beam 10 and the existing reinforced concrete column 1, while reducing the stress concentration phenomenon caused by the deformation of the assembled connection node, and improving the seismic performance and durability of the overall structure.

[0050] It should be noted that the shear member 3 is preferably a steel plate with a thickness of 8 mm and a length of 50 mm, a steel plate with a thickness of 10 mm and a length of 100 mm, or a steel plate with a thickness of 20 mm and a length of 150 mm.

[0051] It should be noted that the shear members 3 are preferably arranged at intervals of 140 mm in the longitudinal direction, 120 mm in the transverse direction, 150 mm in the longitudinal direction, 100 mm in the transverse direction, or 160 mm in the longitudinal direction and 80 mm in the transverse direction.

[0052] like Figure 4 and Figure 5 As shown, in this embodiment, the transverse connector 4 includes a transverse trapezoidal connecting plate 4-1, and top plates 4-2 are vertically welded at both ends of the connecting plate 4-1. The connecting plate 4-1 and the top plate 4-2 are made of steel plates or steel sections, and their thickness is 8mm~16mm, the length is 50mm~150mm, and the width is 50mm~100mm. Multiple transverse connectors 4 are arranged at intervals of 140mm~160mm, the number of multiple transverse connectors 4 is more than two, and the horizontal heights of the two transverse connectors 4 are respectively the same as the horizontal heights of the upper flange and the lower flange of the steel beam 10, and more than two first high-strength bolts 5 are arranged on each top plate 4-2 of the transverse connector 4. By controlling the structure and size of the transverse connector 4, the overall stiffness of the node is effectively guaranteed, and the steel end plate 2 is prevented from being deformed or displaced during the stress process. At the same time, the bending and shearing properties of the node are improved, ensuring the stability and safety of the structure under the action of earthquakes and the like. At the same time, its height is kept at the same level as the flange of the steel beam 10, which can ensure that the bending moment of the flange of the steel beam 10 is transmitted to the existing reinforced concrete column 1, thereby improving the seismic resistance and durability of the overall structure.

[0053] It should be noted that the connecting plate 4-1 and the top plate 4-2 are preferably 10 mm thick, 100 mm long, 80 mm wide, 8 mm thick, 150 mm long, 50 mm wide or 16 mm thick, 50 mm long, 100 mm wide.

[0054] In this embodiment, the diameter of the first high-strength bolt 5 is 16 mm to 22 mm, and the material is high-strength alloy steel with a yield strength exceeding 1000 MPa. By controlling the parameters of the first high-strength bolt 5, it is precisely matched with the holes on the steel end plate 2 and the transverse connector 4 to ensure uniform force distribution during tightening and avoid local stress concentration. The installation of the first high-strength bolt 5 can effectively improve the connection strength of the assembled connection node, reduce the displacement and deformation in the assembled connection node, and ensure the reliability of the connection between the steel beam 10 and the concrete column.

[0055] It should be noted that the diameter of the first high-strength bolt 5 is preferably 16 mm, 18 mm, 20 mm or 22 mm.

[0056] In this embodiment, the strength grade of the post-cast concrete 6 is one level higher than the concrete strength grade used in the existing reinforced concrete column 1. By using the post-cast concrete 6 with a higher strength grade for pouring, the integrity of the assembled connection node is enhanced, the durability and shear resistance of the assembled connection node are improved, and the deformation under extreme loads such as earthquakes is effectively reduced.

[0057] In this embodiment, the end where the cantilever beam 7 is connected to the steel end plate 2 is precisely cut and polished with an error control within 2 mm. Through precise cutting and polishing, the welding accuracy of the cantilever beam 7 and the steel end plate 2 is ensured, and no obvious stress concentration phenomenon is generated during the welding process. The cantilever beam 7 and the steel end plate 2 are welded by a full penetration welding process, and the height and width of the weld seam must comply with relevant structural welding standards to ensure that the assembled connection node can safely transmit force when subjected to force, and meet the strength and durability requirements of the building structure.

[0058] In this embodiment, the connection between the existing reinforced concrete column 1 and the steel end plate 2 is roughened to a depth of 30 mm to 50 mm. By controlling the depth of the roughening treatment, it is ensured that the shear member 3 can penetrate into the interior of the existing reinforced concrete column 1 to increase the bonding force of the node. After the roughening treatment, the surface should maintain a uniform roughness and avoid large smooth areas to ensure that the subsequently poured concrete can be fully combined with the existing concrete column surface and the shear member 3, thereby enhancing the overall force performance of the assembled connection node.

[0059] It should be noted that the depth of the roughening process is preferably 30 mm, 40 mm or 50 mm.

[0060] In this embodiment, the cross-sectional dimensions of the area enclosed by the steel end plates 2 fixedly installed around the existing reinforced concrete column 1 are larger than the cross-sectional dimensions of the existing reinforced concrete column 1. By controlling the cross-sectional dimensions of the area enclosed by the steel end plates 2, it is ensured that the assembled connection node has sufficient rigidity.

[0061] The construction method of the assembled connection node between the existing reinforced concrete column and the newly added steel beam of the present invention is described in detail through Example 2.

[0062] Example 2

[0063] This embodiment includes the following steps:

[0064] Step 1: roughening the area of ​​the existing reinforced concrete column 1 where the steel end plate 2 is to be installed to obtain a roughened existing reinforced concrete column;

[0065] Step 2: Cut, grind and clean the ends of the cantilever beam 7 in sequence, and then connect the four cleaned cantilever beams 7 to the ends of the four steel end plates 2 without the shear members 3 by full penetration welding to obtain four connected cantilever beams and steel end plates;

[0066] Step 3, assemble the four connected cantilever beams and steel end plates obtained in step 2 with the roughened existing reinforced concrete column obtained in step 1, and insert the shear member 3 of the steel end plate 2 into the roughened existing reinforced concrete column to obtain the roughened existing reinforced concrete column with the cantilever beam and the steel end plate installed;

[0067] Step 4: Connect the adjacent steel end plates 2 in the roughened existing reinforced concrete column for installing the cantilever beam and the steel end plate obtained in step 3 by using the first high-strength bolts 5 and the transverse connectors 4 to obtain a pre-fixed assembly;

[0068] Step 5. The area between the steel end plate 2 and the roughened existing reinforced concrete column in the pre-fixed assembly obtained in step 4 and the connection between adjacent steel end plates 2 are poured with post-cast concrete 6, and then maintained. The other end of the cantilever beam 7 is then bolted and welded to the newly added steel beam 10 through the second high-strength bolts 8 and the mounting plate 9 to obtain an assembled connection node between the existing reinforced concrete column and the newly added steel beam.

[0069] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An assembled connection node between an existing reinforced concrete column and a newly added steel beam, characterized in that: The assembled connection node comprises four steel end plates (2) fixedly installed around the existing reinforced concrete column (1); the steel end plates (2) are connected to the existing reinforced concrete column (1) via a plurality of shear members (3) welded on the surface of the steel end plates (2); adjacent steel end plates (2) are connected to each other via a plurality of transverse connectors (4) and a plurality of first high-strength bolts (5); the connection between the steel end plates (2) and the existing reinforced concrete column (1) and between adjacent steel end plates (2) are filled with post-cast concrete (6); a cantilever beam (7) is fully penetrated and welded on each steel end plate (2); the other end of the cantilever beam (7) is bolt-welded to a steel beam (10) via a second high-strength bolt (8) and a mounting plate (9).

2. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The thickness of the steel end plate (2) and the thickness of the web of the steel beam (10) are both 10 mm to 20 mm.

3. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The shear-resistant member (3) is a steel plate with a thickness of 8 mm to 20 mm and a length of 50 mm to 150 mm. A plurality of the shear-resistant members (3) are distributed in an array on the steel end plate (2), with one arranged at intervals of 140 mm to 160 mm in the longitudinal direction and one arranged at intervals of 80 mm to 120 mm in the transverse direction.

4. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The transverse connector (4) comprises a transverse trapezoidal connecting plate (4-1), both ends of which are vertically welded with a top plate (4-2), the connecting plate (4-1) and the top plate (4-2) are both made of steel plates or steel sections, and the thickness is 8 mm to 16 mm, the length is 50 mm to 150 mm, and the width is 50 mm to 100 mm, and a plurality of transverse connectors (4) are arranged one at intervals of 140 mm to 160 mm, the number of the plurality of transverse connectors (4) is more than two, and the horizontal heights of the two transverse connectors (4) are respectively the same as the horizontal heights of the upper flange and the lower flange of the steel beam (10), and each top plate (4-2) of the transverse connector (4) is provided with more than two first high-strength bolts (5).

5. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The diameter of the first high-strength bolt (5) is 16 mm to 22 mm, and the material is high-strength alloy steel with a yield strength exceeding 1000 MPa.

6. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The strength grade of the post-cast concrete (6) is one level higher than the strength grade of the concrete used in the existing reinforced concrete column (1).

7. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The end of the cantilever beam (7) connected to the steel end plate (2) is precisely cut and polished with an error control within 2 mm.

8. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The connection between the existing reinforced concrete column (1) and the steel end plate (2) is roughened to a depth of 30 mm to 50 mm.

9. The assembled connection node of an existing reinforced concrete column and a newly added steel beam according to claim 1, characterized in that: The cross-sectional dimensions of the area enclosed by the steel end plates (2) fixedly installed around the existing reinforced concrete column (1) are greater than the cross-sectional dimensions of the existing reinforced concrete column (1).

10. A construction method for an assembled connection node between an existing reinforced concrete column and a newly added steel beam as claimed in any one of claims 1 to 9, characterized in that: The method comprises the following steps: Step 1: roughening the area of ​​the existing reinforced concrete column (1) where the steel end plate (2) is to be installed, to obtain a roughened existing reinforced concrete column; Step 2: Cut, grind and clean the ends of the cantilever beams (7) in sequence, and then connect the four cleaned cantilever beams (7) and the ends of the four steel end plates (2) without the shear members (3) by a full penetration welding process, to obtain four connected cantilever beams and steel end plates; Step 3, assembling the four connected cantilever beams and steel end plates obtained in step 2 and the roughened existing reinforced concrete column obtained in step 1, and inserting the shear member (3) of the steel end plate (2) into the roughened existing reinforced concrete column to obtain the roughened existing reinforced concrete column with the cantilever beam and the steel end plate installed; Step 4: Connect the adjacent steel end plates (2) in the roughened existing reinforced concrete column for installing the cantilever beam and the steel end plates obtained in step 3 by using the first high-strength bolts (5) and the transverse connectors (4) to obtain a pre-fixed assembly; Step 5: The area between the steel end plate (2) and the roughened existing reinforced concrete column in the pre-fixed assembly obtained in step 4 and the connection between the adjacent steel end plates (2) are cast with post-cast concrete (6), and then cured. The other end of the cantilever beam (7) is then bolted and welded to the newly added steel beam (10) through a second high-strength bolt (8) and a mounting plate (9) to obtain an assembled connection node between the existing reinforced concrete column and the newly added steel beam.

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