A method for installing a new beam for reinforcing an existing reinforced concrete column

Abstract

The present application relates to the technical field of reinforcing technology of building structure beam-column joint, and particularly relates to a method for installing a new beam for reinforcing an existing reinforced concrete column; the method first surrounds and bonds outer steel around the concrete column at the planned position of the new beam and arranges through-length bolts, then welds connecting steel plates on the surface of the outer steel and arranges through-length bolts, then welds I-shaped steel at the connecting steel plates and forms a "H" shaped structure, and finally welds through-length bars on the I-shaped steel of the "H" shaped structure and completes the formwork, concrete pouring and maintenance of the new beam; the present application forms a force whole by the composite connection system of outer steel bonding, through-length bolt mechanical anchoring, connecting steel plate welding transition and H-shaped I-shaped steel force transmission, realizes effective transmission and dispersion of the load between the beam and the column, and improves the integrity, bearing capacity and seismic performance of the joint; the method is simple in construction and controllable in cost, and is suitable for the reconstruction of existing building space and the seismic reinforcement demand in urban renewal.

Description

Technical Field

[0001] This invention relates to the field of beam-column joint reinforcement technology in building structures, and particularly to a method for installing new beams for reinforcing existing reinforced concrete columns. Background Technology

[0002] The core pain point in the renovation and reinforcement of existing reinforced concrete structures in my country's urban renewal process lies in the significant technical defects in the connection methods between existing columns and new beams, making it difficult to balance connection reliability and seismic safety: First, in the traditional rebar connection method, the rebar depth is limited by the cross-sectional dimensions of the existing column, which easily leads to insufficient anchorage length. Furthermore, incomplete cleaning of the rebar ducts can cause a decrease in bond strength, making it prone to problems such as anchorage failure and joint cracking under seismic loading. Second, although external steel connection can improve load-bearing capacity, the bonding performance between steel and concrete is poor, and relative slippage is easily generated under repeated seismic loading, resulting in insufficient joint ductility.

[0003] In the prior art, a utility model patent with authorization publication number CN224078750U and titled "A Prefabricated Beam Addition and Renovation Structure for Existing Beam-Column Joints" discloses a renovation structure for adding a concrete beam at an existing beam-column joint. This structure includes an existing concrete column and an existing concrete beam. The new concrete beam is placed on the side of the existing concrete column, and a π-shaped welded beam perpendicular to the existing concrete column is installed within the new concrete beam. Reinforcing steel plates, including column-side steel plates, beam-side steel plates, beam-top steel plates, and beam-bottom steel plates, are installed at the joint location. The column-side steel plates are fixedly connected to the existing concrete column by reinforcing bars, and the beam-side steel plates are fixed by chemical anchors. The structure is connected to the external beam via the π-shaped welded beam. The combined effect of reinforced concrete and the reinforcement of the core area of ​​the joint by the reinforcing steel plate achieves an effective connection between the new beam and the existing column and enhances the strength of the core area of ​​the joint. It has the effect of reducing the number of rebars in the core area and enhancing the strength of the core area of ​​the joint. However, it has the following problems: This scheme relies on the existence of the existing concrete beam and is only applicable to the addition of beams at existing beam-column joints. It cannot be applied to the connection of new beams in places where there are no existing beams in the column. The steel plate on the column side is fixed by the rebar, and the depth of the rebar is limited by the column cross-sectional size, resulting in insufficient anchorage reliability in low-strength concrete. The reinforcement steel plate system involves a variety of steel plates and a large number of tie bolts, which makes the structure complex and the construction process complicated.

[0004] In the prior art, the invention with patent publication number CN119711784A and titled "A Prefabricated Connection Node for an Existing Reinforced Concrete Column and a Newly Added Steel Beam and its Construction Method" discloses a prefabricated connection node for connecting a new steel beam to an existing reinforced concrete column. This 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 via multiple shear-resistant members welded to their surfaces. Adjacent steel end plates are interconnected via transverse connectors and first high-strength bolts. Post-cast concrete is used to fill the space between the steel end plates and the column. Each steel end plate has a cantilever beam welded with full penetration welding. The cantilever beam is connected to the steel beam via second high-strength bolts and mounting plates. This method involves installing steel end plates around the column and... The method utilizes shear-resistant members inserted into the roughened concrete to achieve column-side anchorage, and uses cantilever beams and high-strength bolts to achieve modular assembly connection of the newly added steel beams. This realizes the prefabricated connection between the steel beams and reinforced concrete columns, which has the advantages of high construction efficiency, reduced on-site welding complexity, and excellent stress performance. However, it has the following problems: This solution is only suitable for connecting newly added steel beams, not for connecting newly added reinforced concrete beams; the steel end plates are only attached to the four sides of the column rather than wrapping the column body, and the cooperative stress with the concrete column depends on the shear-resistant members being inserted into the roughened layer and the bonding of the post-poured concrete. The embedding depth of the shear-resistant members is only 30mm to 50mm. Under the action of seismic cyclic loads, relative slippage is likely to occur between the steel end plates and the column body, resulting in insufficient connection reliability. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to propose a method for installing new beams for reinforcing existing reinforced concrete columns. This method first involves bonding the existing concrete column with an outer steel sheath and reinforcing it with bolts. Then, a connecting steel plate is welded onto the outer steel sheath and reinforced with bolts. The connecting steel plate forms a limited bearing surface for the new beam. Subsequently, an effective connection between the beam and column is achieved by welding a U-shaped I-beam to the connecting steel plate and the continuous reinforcement of the new beam. The joint formed by this method has good integrity, enhances the connection effectiveness at the joint, and effectively improves the seismic performance of the joint.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for installing new beams to reinforce existing reinforced concrete columns includes the following steps: S1: At the height of the planned new beam 7 between the two concrete columns 1, surround and bond the outer steel 2. Arrange a row of first through bolts 3 at the upper and lower edges of the outer steel 2. The first through bolts 3 pass through the concrete column 1 and are fixed with nuts. S2: Weld a connecting steel plate 4 at the middle position of the outer steel 2 mentioned in step S1. The horizontal width of the connecting steel plate 4 is the same as the horizontal width of the outer steel 2. A row of second through bolts 5 are arranged at the upper and lower edges of the connecting steel plate 4. The second through bolts 5 pass through the concrete column 1 and are fixed with nuts. S3: Weld four I-beams 6 at the middle position of the connecting steel plate 4 described in step S2 to form a “㠭” shaped structure; S4: In step S3, a continuous reinforcing bar 8 is welded to the middle of the upper flange plate of the two upper I-beams 6 and the middle of the lower flange plate of the two lower I-beams 6, so that the two concrete columns 1 in step S1 are connected by the four continuous reinforcing bars 8 welded on the “T”-shaped structure. S5: Tie the stirrups 9 along the continuous reinforcement 8 as described in step S4, complete the formwork, concrete pouring and curing of the newly added beam 7, and complete the connection and reinforcement of the newly added beam 7 between the two concrete columns 1.

[0007] Furthermore, in step S1, the vertical width of the outer steel 2 is not less than the horizontal cross-sectional width of the concrete column 1, and the thickness of the outer steel 2 is ≥10mm.

[0008] Furthermore, in step S1, the number of first through bolts 3 in each row is not less than 3, and the distance between the first through bolts 3 and the edge of the outer steel 2 is ≥50mm.

[0009] Furthermore, the thickness of the connecting steel plate 4 in step S2 is ≥10mm.

[0010] Furthermore, the outer steel 2 mentioned in step S1 and the connecting steel plate 4 mentioned in step S2 are made of Q235 or Q355 grade steel.

[0011] Furthermore, in step S2, the number of second through bolts 5 in each row is not less than 4, and the distance between the second through bolts 5 and the edge of the connecting steel plate 4 is ≥25mm.

[0012] Furthermore, the welding method between the connecting steel plate 4 and the outer steel 2 in step S2 is full welding, and the welding method between the I-beam 6 and the connecting steel plate 4 in step S3 is full welding.

[0013] Furthermore, in step S3, the spacing between adjacent I-beams 6 is ≥10mm.

[0014] Furthermore, in step S4, the distance between one end of the continuous rib 8 and the adjacent connecting steel plate 4 is ≤5mm.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In step S1 of the present invention, the bonding of the outer steel can utilize the high tensile and compressive strength of the steel to constrain the core area of ​​the concrete column, reduce the lateral deformation of the concrete, and enhance the bearing capacity and seismic performance of the column. The outer steel is further fixed to the surface of the concrete column by a row of first through bolts. This can upgrade the connection between the outer steel and the concrete column from a single bonding anchorage to a dual fixing mode of "bonding + mechanical anchorage". This effectively prevents the outer steel and the column interface from peeling or relative slippage under the action of seismic reciprocating load, and ensures that the outer steel and the concrete column cooperate in bearing the force and the load is stably transmitted.

[0016] (2) In step S2 of the present invention, by welding connecting steel plates on the surface of the outer steel, a reliable mounting surface is provided for the installation of the “T”-shaped I-beam, forming a clear force transmission path of “new beam → connecting steel plate → outer steel → concrete column”; at the same time, second long bolts are arranged on the upper and lower edges of the connecting steel plate to penetrate the concrete column for fixation, further improving the buckling resistance of the connecting steel plate, avoiding local deformation under cyclic load, ensuring the continuity and stability of load transmission, and making up for the problem of insufficient ductility of simple welded connection under seismic cyclic load.

[0017] (3) In steps S3 to S4 of the present invention, four I-beams are welded together to form a “㠭”-shaped structure as the core force transmission carrier between the new beam reinforcement and the connecting steel plate. The upper and lower continuous reinforcements of the new beam are welded to the upper and lower flange plates of the I-beams respectively. The bending and shear resistance of the I-beams are used to effectively transfer the bending moment and shear force at the beam end to the connecting steel plate. At the same time, the “㠭”-shaped layout disperses the load concentrated at the beam reinforcement welding point to the surrounding area, avoiding excessive local stress at the node and reducing the risk of cracking.

[0018] In summary, this invention utilizes a composite connection system consisting of external steel bonding, continuous bolt mechanical anchoring, welded transition of connecting steel plates, and force transmission via U-shaped I-beams. This system enables the components to form a unified load-bearing structure, effectively transferring and distributing loads between beams and columns. It enhances the integrity, bearing capacity, and seismic performance of the joints, achieving the seismic design goal of "strong joints and weak components." This system can resist horizontal loads acting on the structure under various natural disasters such as earthquakes and windstorms. At the same time, the construction method is relatively simple, which helps to reduce construction difficulty. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0020] Figure 2 This is a side view of the node structure of the present invention.

[0021] Figure 3 This is a rear view of the overall structure of the present invention.

[0022] Figure 4 This is a simulation diagram of stress distribution in traditional rebar reinforcement.

[0023] Figure 5 This is a simulation diagram of the stress distribution of the novel node reinforcement in Example 1.

[0024] Figure 6 This is a simulation diagram of the stress distribution of the I-beam in the novel node reinforcement of Example 1.

[0025] In the attached diagram: 1. Concrete column; 2. Outer steel cladding; 3. First continuous bolt; 4. Connecting steel plate; 5. Second continuous bolt; 6. I-beam; 7. Newly added beam; 8. Continuous reinforcement; 9. Stirrups. Detailed Implementation

[0026] To address the technical problems of "insufficient connection reliability and poor seismic performance" in the connection between existing reinforced concrete columns and new reinforced concrete beams, this invention provides a novel node connection method that balances connection strength and seismic performance, and can meet the dual needs of spatial reconstruction and seismic reinforcement of existing buildings in urban renewal.

[0027] The following is in conjunction with the appendix Figure 1 To be continued Figure 6 The present invention will be further described in detail below: like Figure 1 As shown, in a method for installing a new beam to reinforce an existing reinforced concrete column, the “U”-shaped structure formed by the outer steel 2, connecting steel plate 4, and four I-beams 6 is symmetrical about the central axis of the concrete column 1.

[0028] Before reinforcing the existing reinforced concrete column 1, an angle grinder with a grinding wheel should be used to grind the area enclosed by the planned new beam to remove laitance, weathered layer and oil stains. The grinding depth should be 2mm to expose fresh aggregate and form a rough surface. After cleaning the dust, wipe the surface with acetone and let it dry before use.

[0029] Before reinforcement, the outer steel cladding 2 requires the preparation of a modified epoxy resin structural adhesive. The adhesive should be thoroughly mixed according to the product instructions to avoid air bubbles. The structural adhesive should be evenly applied to the area encased in the concrete column 1 and the inner bonding surface of the outer steel cladding 2, with a thickness controlled at 3mm, covering the entire contact area of ​​the outer steel cladding 2. The outer steel cladding 2 should be accurately fitted onto the pre-defined area of ​​the concrete column 1, ensuring that the width of the outer steel cladding 2 matches the width of the concrete column 1 and its length is twice the height of the new beam 7. During fitting, push it from the center outwards to expel air and temporarily fix it with clamps. Then, at least six first-length bolts 3 (M10 bolts) should be arranged in two rows and three columns at a distance from the upper and lower edges of the outer steel cladding 2. The vertical spacing should be evenly distributed according to the width of the outer steel cladding 2, and the M10 bolts should be arranged parallel to the length of the new beam 7. Tighten the bolts to complete the permanent fixation, ensuring a tight and reliable bond between the outer steel cladding 2 and the concrete column 1. Allow it to cure until the structural adhesive initially sets, for at least 24 hours.

[0030] The installation position of the new beam 7 is determined on the surface of the outer steel 2. A connecting steel plate 4 is welded using a full welding method. The width of the connecting steel plate 4 is the same as the width of the outer steel 2. After welding, at least 8 second through bolts are arranged in two rows and four columns at least 25mm away from the edge of the connecting steel plate 4. The second through bolts can be M12 through bolts. The vertical spacing is evenly arranged according to the width of the connecting steel plate 4. Tighten the through bolts 5 to further reinforce the connecting steel plate 4 and ensure the reliability of the welding joint and anchoring structure.

[0031] After the outer steel cladding 2 has been properly bonded and cured, the welding points of the four I-beams 6 are marked at the pre-set positions on the connecting steel plate 4 according to the cross-sectional dimensions of the new beam 7 and the location of the reinforcing bars. A minimum 10mm gap is maintained between the I-beams. The four I-beams 6 are then welded to form a "㠭" shaped structure. Before welding, the welding surfaces of the connecting steel plate 4 and the I-beams 6 are cleaned to remove surface rust, oil, and adhesive residue, ensuring a clean welding surface. The four I-beams 6 are welded sequentially using a full-welding method to form a "㠭" grid layout. During the welding process, the positioning accuracy is strictly controlled to ensure that the longitudinal axis of symmetry of the concrete column 1 and the new beam 7 are collinear, and that the three longitudinal axes of symmetry and the three transverse axes of symmetry of the outer steel cladding 2, the connecting steel plate 4, and the "㠭" shaped I-beam structure are all coplanar with the longitudinal and transverse axes of symmetry of the concrete column 1 and the new beam 7, respectively. The weld height should meet the design requirements and should generally be no less than 6mm. After welding, the slag should be removed in time, and the weld quality should be checked to ensure that there are no defects such as false welding, missing welding, slag inclusion, cracks, etc. If necessary, weld flaw detection should be carried out.

[0032] The two upper continuous reinforcing bars 8 of the newly added beam 7 are welded to the middle of the upper flange plates of the two upper I-beams 6 in the "U"-shaped structure, and the two lower continuous reinforcing bars of the newly added beam 7 are welded to the middle of the lower flange plates of the two lower I-beams 6 in the "U"-shaped structure; the continuous reinforcing bars 8 in the beam are welded to the middle of the outer flange plates of the I-beams 6, with the end of the reinforcing bar no more than 5mm from the connecting steel plate 4. During welding, the weld length and welding quality are controlled to ensure that the continuous reinforcing bars 8 in the newly added beam 7 are firmly connected to the I-beams 6, meeting the requirements for load transfer and structural bearing capacity.

[0033] The additional concrete beam needs to be welded to the I-beam 6 and the continuous reinforcing bar 8 of the new beam 7 after the weld quality is accepted. Then, the stirrups 9 of the new concrete beam are tied according to the design drawings. The stirrups 9 in the beam are arranged from the edge of the I-beam 6. The stirrups near the core area are spaced at 50mm and have a length of 500mm. The stirrups at other positions are spaced at 100mm. Ensure that the reinforcing bars do not conflict with the I-beam 6 and that the thickness of the protective layer meets the requirements of the specification. The starting position of the stirrups should be set at the edge of the length direction of the I-beam. The beam formwork is erected, and the formwork joints are tight and the support is firm. Fine stone concrete with a strength grade of not less than C25 is poured and vibrated to compaction using an immersion vibrator to avoid under-vibration or over-vibration. After pouring, cover and moisturize for curing. The curing time is not less than 14 days until the concrete reaches the design strength. After completion, the additional concrete beam (7) is formed.

[0034] like Figure 3 As shown, this invention uses a composite method of "steel bonding reinforcement + welding connection + bolt reinforcement" to make the components form a whole that bears the load, effectively transfers and distributes the load, improves the stability and seismic resistance of the nodes, and is easy to construct and cost-controllable, making it suitable for the needs of existing building space reconstruction and seismic reinforcement in urban renewal.

[0035] In this method for installing newly added beams, the specific parameters in Example 1 are as follows: like Figure 2 As shown, a 10mm thick, annular outer steel plate 2, the same width as the concrete column 1, is installed at the location of the newly added beam 7 on the concrete column 1. The outer steel plate 2 is bonded to the column with structural adhesive. Its length is twice the height of the newly added concrete beam 7. Six M10 continuous bolts, arranged in two rows and three columns, are installed 50mm from the top and bottom edges of the outer steel plate 2 in the vertical direction to secure it. The spacing is evenly distributed according to the column width. On each of the two sides where the annular outer steel plate 2 connects to the beam, a connecting steel plate 4, 20mm thick, with the same width as the annular outer steel plate 2, and a height extending 60mm from the top and bottom edges of the newly added concrete beam 7, is installed. Eight M12 continuous bolts, arranged in two rows and four columns, are installed 25mm from the edges of the connecting steel plates 4, with the spacing evenly distributed according to the column width, to enhance the beam-column connection. Four 200mm long I-beams 6 are welded onto the connecting steel plates 4 according to the location of the newly added concrete beam 7. To prevent collisions between adjacent I-beams during subsequent stress, the spacing between adjacent I-beams is 10mm. The continuous reinforcing bar 8 is welded to the middle of the outer flange plate of the I-beam 6, with the end of the reinforcing bar 5mm away from the edge of the connecting steel plate 4.

[0036] The stirrups 9 in the beam are arranged starting from the edge of the I-beam 6. The stirrups near the core area of ​​the node are spaced at 50mm intervals and are 500mm long. The stirrups at other locations are spaced at 100mm intervals. The concrete strength grade of the newly added beam 7 should not be higher than that of the column concrete and not lower than C25 (if a new concrete beam 7 is added to an existing concrete column with dimensions of 300mm×300mm, widened to 200mm and height of 300mm, then the outer steel 2 is 600mm long and 300mm wide, the vertical spacing of the M10 continuous bolts is 100mm, the connecting steel plate 4 is 300mm wide and 420mm long, the I-beam 6 is 130mm high, 80mm wide, and 6mm thick, and the vertical spacing of the M12 continuous bolts is 75mm).

[0037] Simulation test verification: Based on the parameters of Example 1, a three-dimensional solid model of the node connection method of the present invention was established using Abaqus finite element analysis software. The material constitutive model adopted was elastoplastic. Vertical loads were applied to the newly added beams, and the stress performance and stress distribution of the nodes were analyzed.

[0038] like Figure 4 As shown, under traditional rebar anchoring reinforcement methods, rebar anchoring is prone to anchorage failure, joint cracking, and insufficient ductility under cyclic loads.

[0039] like Figure 5 As shown, under vertical load, the Mises stress at the node in Example 1 is mainly concentrated in the newly added beam-column connection area, with the maximum stress at the interface between the outer steel and the connecting steel plate being approximately 458 MPa, while the stress levels in other areas are relatively low; Figure 6 As shown in Example 1, the stress of the "㠭"-shaped I-beam is distributed in a gradient along its length, with higher stress near the connecting steel plate and lower stress away from it. The load is effectively dispersed to all sides through the I-beam. The stress distribution on the surface of the outer steel is uniform, and there is no obvious stress concentration in the bolt area along the entire length. This indicates that the dual fixing mode of bonding and mechanical anchoring enables the outer steel and the concrete column to cooperate well in bearing the force.

[0040] The above results verify that the force transmission path of the composite connection system proposed in this invention, which consists of "outer steel bonding + continuous bolt anchoring + connecting steel plate transition + I-beam force transmission", is clear, the force is reasonable, and the nodes have good integrity and load-bearing capacity.

[0041] The working principle of this invention is as follows: 1. Cooperative load-bearing effect of steel cladding and concrete column: Structural adhesive is used to bond the steel cladding to the concrete column. The steel cladding constrains the core area of ​​the column, reduces lateral deformation, and cooperates in bearing loads. The core innovation of this invention lies in the use of M10 continuous bolts along the upper and lower edges of the steel cladding, penetrating the concrete column and securing them with nuts. This elevates the steel cladding from a single "bonding anchorage" to a dual fixing mode of "bonding + mechanical anchorage," effectively preventing peeling or slippage of the bonded steel interface under seismic cyclic loads and ensuring stable force transmission between the steel cladding and the column.

[0042] 2. Force transmission transition of connecting steel plates: The connecting steel plates are fully welded to the outer steel and reinforced by M12 through bolts that penetrate the column, forming a force transmission path of "new beam → connecting steel plate → outer steel → concrete column"; the through bolts improve the buckling resistance of the steel plates and make up for the problem of insufficient ductility of pure welded connections under cyclic loads.

[0043] 3. Load Dispersion of “U”-Shaped I-Beams: Four I-beams form a “U”-shaped structure as the core force transmission carrier. The upper and lower continuous reinforcement bars of the beam are welded to the upper and lower flange plates of the I-beams, respectively, so that the bending moment and shear force at the beam end are transferred to the connecting steel plate through the I-beams. The “U”-shaped layout disperses the concentrated load to all sides, reducing the risk of joint cracking.

[0044] 4. Overall seismic resistance coordination: Each component is arranged symmetrically about the column center axis to avoid eccentric stress; the friction and bonding of the outer steel-bonded steel interface consumes seismic energy; the rigid frame formed by the "T"-shaped I-beam and connecting steel plate improves the ductility of the nodes; the composite connection system constrains node deformation and prevents brittle failure, achieving the seismic resistance goal of strong nodes and weak components.

Claims

1. A method for installing new beams for reinforcing existing reinforced concrete columns, comprising the following steps: S1: At the height of the planned new beam (7) between the two concrete columns (1), the outer steel (2) is surrounded and bonded. A row of first through bolts (3) is arranged at the upper and lower edges of the outer steel (2). The first through bolts (3) pass through the concrete column (1) and are fixed with nuts. S2: Weld a connecting steel plate (4) at the middle position of the outer steel (2) mentioned in step S1. The horizontal width of the connecting steel plate (4) is consistent with the horizontal width of the outer steel (2). A row of second through bolts (5) is arranged at the upper and lower edges of the connecting steel plate (4). The second through bolts (5) penetrate the concrete column (1) and are fixed with nuts. S3: Weld four I-beams (6) at the middle position of the connecting steel plate (4) described in step S2 to form a "㠭" shaped structure; S4: Weld a continuous reinforcing bar (8) to the middle of the upper flange plate of the two upper I-beams (6) and the middle of the lower flange plate of the two lower I-beams (6) of the "㠭" shaped structure described in step S3, so that the two concrete columns (1) described in step S1 are connected by the four continuous reinforcing bars (8) welded on the "㠭" shaped structure. S5: Tie the stirrups (9) along the continuous bar (8) described in step S4, complete the formwork, concrete pouring and curing of the subsequent new beam (7), and finally complete the connection and reinforcement of the new beam (7) between the two concrete columns (1).

2. The method for installing new beams for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The vertical width of the outer steel (2) in step S1 is not less than the horizontal cross-sectional width of the concrete column (1), and the thickness of the outer steel (2) is ≥10mm.

3. The method for installing new beams for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The number of first through bolts (3) in each row in step S1 is not less than 3, and the distance between the first through bolt (3) and the edge of the outer steel (2) is ≥50mm.

4. The method for installing new beams for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The thickness of the connecting steel plate (4) in step S2 is ≥10mm.

5. The method for installing a new beam for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The outer steel (2) mentioned in step S1 and the connecting steel plate (4) mentioned in step S2 are made of Q235 or Q355 grade steel.

6. The method for installing a new beam for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The number of second through bolts (5) in each row in step S2 shall not be less than 4, and the distance between the second through bolt (5) and the edge of the connecting steel plate (4) shall be ≥25mm.

7. The method for installing new beams for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The welding method of the connecting steel plate (4) and the outer steel (2) in step S2 is full welding, and the welding method of the I-beam (6) and the connecting steel plate (4) in step S3 is full welding.

8. The method for installing a new beam for reinforcing existing reinforced concrete columns as described in claim 1, characterized in that, The spacing between adjacent I-beams (6) in step S3 is ≥10mm.

9. The method for installing a new beam for reinforcing an existing reinforced concrete column as described in claim 1, characterized in that, The distance between one end of the continuous rib (8) in step S4 and the adjacent connecting steel plate (4) is ≤5mm.

Images