A reinforcing structure suitable for the cooperative work of an externally wrapped steel beam-column joint and a preparation method thereof

Abstract

This invention provides a reinforcement structure and its fabrication method suitable for the collaborative operation of externally encased steel beam-column joints, relating to the field of building structure reinforcement engineering technology. This invention achieves coordinated force distribution and reliable connection among the three components by designing an integrated structure of a cylindrical steel-encased reinforcement unit, a beam steel-encased reinforcement unit, and a triangular prism collaborative support unit. This significantly improves the compressive, shear, and seismic performance of the cylinder, enhances the bending and shear bearing capacity and stiffness of the beam, ensures smooth load transfer between the beam and column, and ultimately improves the safety, stability, and durability of the entire reinforcement structure.

Description

Technical Field

[0001] This invention relates to the field of building structure reinforcement engineering technology, specifically to a structure suitable for the collaborative work of external steel beam-column joints and its preparation method. Background Technology

[0002] With the advancement of urbanization in my country, many existing buildings face problems such as insufficient structural bearing capacity and decreased stability due to increased service life, higher load standards, functional layout adjustments, or updates to seismic design codes. These buildings require reinforcement and renovation to improve their mechanical performance. In building frame structures, the column-beam joint is the core of the load-bearing unit, and its bearing capacity directly determines the safety and stability of the entire structure. Currently, reinforcement technologies for cylindrical members mainly include steel plate bonding and cross-section enlargement. Among these, steel plate bonding is widely used due to its convenient construction and significant reinforcement effect. Its core principle is to adhere steel plates to the surface of the column using structural adhesive, allowing the steel plate and the column to share the load collaboratively, thus improving compressive and shear resistance. However, this technology has significant drawbacks: firstly, the bonding performance of the structural adhesive is easily affected by environmental temperature and humidity, as well as the quality of the substrate treatment, and may experience aging and peeling during long-term use, negatively impacting the reinforcement system.

[0003] For beam reinforcement, existing technologies mainly include steel-clad reinforcement, fiber-reinforced composite material bonding, and cross-section enlargement. Steel-clad reinforcement improves bending and shear resistance by wrapping steel plates around the tension and compression zones of the beam. However, it suffers from two key problems: First, the connection between the steel plate and the beam is not reliable enough. Existing processes often use simple bonding or anchor bolts, which can easily lead to separation of the steel plate from the concrete interface under load. Second, the reinforcement range is difficult to adequately cover critical load-bearing sections, especially at beam-column connections. The steel plate often does not extend to the core area of ​​the beam support, leaving the joint weak and unable to effectively transfer beam loads to the column. Furthermore, existing beam reinforcement technologies often treat the beam alone, or when the column and adjacent beams are reinforced separately, the path of beam load transfer to the column is unclear, failing to consider coordination with the column reinforcement system, leading to uncoordinated stress at beam-column joints. After steel reinforcement of the beam, the beam stiffness increases, but the connection strength with the column is not enhanced synchronously. Under load, excessive deformation or even cracking easily occurs at the connection between the beam bottom and the column. In some projects, additional supports are used to assist in supporting the beam, but these supports are mostly rectangular structures with poor fit with the beam bottom and column, low force transmission efficiency, and cannot adapt to the curved surface of the column, resulting in insufficient support stability. Therefore, developing an integrated reinforcement structure and construction method that can achieve coordinated force sharing between the column and beam, improve the connection strength of the joints, and enhance the stability of the beam reinforcement is a key requirement to address the shortcomings of existing technologies and is of great significance to promoting the development of building structure reinforcement technology. Summary of the Invention

[0004] To address the problems in existing technologies such as asynchronous reinforcement of cylindrical and beam components, poor synergistic load-bearing effect, poor joint force transmission, and insufficient stability of the reinforced beam, this invention provides a reinforcement method suitable for the coordinated operation of externally encased steel beam-column joints. By designing an integrated structure of a cylindrical steel-encased reinforcement unit, a beam steel-encased reinforcement unit, and a triangular prism collaborative support unit, the method achieves coordinated load-bearing and reliable connection among the three components. This significantly improves the compressive, shear, and seismic performance of the cylindrical component, enhances the bending, shear bearing capacity and stiffness of the beam, ensures smooth load transmission between the beam and column, and ultimately improves the safety, stability, and durability of the entire reinforced structure.

[0005] The reinforcement method for the coordinated operation of externally-enclosed steel beam-column joints described in this invention includes the following steps: (1) Conduct an investigation of the cylindrical and beam components in the reinforced area of ​​the external steel beam-column joint; (2) Remove rust and grind the cylindrical surface, then blow it clean to remove dust and debris from the surface; (3) Grind the surface of the beam component to remove the surface laitance and debris of the concrete, grind to a solid concrete base, and the surface flatness error is not greater than 2mm / m; remove dust from the ground surface to ensure that the surface is dry and clean; (4) Prepare an arc-shaped steel plate according to the diameter and design height of the cylinder, and drill holes on the arc-shaped steel plate and the surface of the cylinder; cut and process the steel plate according to the size of the beam component, and drill holes on the surface of the beam and the steel plate; inject chemical anchoring adhesive into the drilled holes on the surface of the cylinder and the surface of the beam, and insert chemical anchor bolts. After the combination is stable, proceed with subsequent construction; the steel plate includes the bottom steel plate of the beam, the side steel plate of the beam, the top steel plate of the beam and the reinforcing gusset plate; (5) Apply an interface treatment agent to the surface of the cylinder, attach the arc-shaped steel plate to the surface of the cylinder, and fix it to the chemical anchor bolt with a nut; apply an interface treatment agent to the surface of the beam, attach the steel plate to the surface of the beam, and fix it to the chemical anchor bolt with a nut; weld and grind the joints of adjacent arc-shaped steel plates and steel plates. (6) Design a triangular prism support unit according to the beam bottom height and the cylinder diameter, and weld reinforcing ribs on the triangular prism support unit; tightly fit the two mating surfaces of the triangular prism support unit with the beam bottom steel plate and the cylindrical arc steel plate respectively, and perform bevel welding to obtain a reinforced structure and complete the construction.

[0006] Preferably, the rust removal treatment in step (2) reaches the Sa2.5 level; the grinding and leveling ensures that the surface flatness error is no greater than 2mm / m.

[0007] Preferably, the chemical anchoring adhesive described in step (4) has a compressive strength ≥100MPa, a tensile strength ≥30MPa, and an applicable temperature of -40℃ to 80℃; Preferably, the chemical anchor in step (4) has a tensile bearing capacity design value ≥150kN and a shear bearing capacity design value ≥120kN.

[0008] Preferably, the arc-shaped steel plate in step (4) is made of Q355 or Q460 high-strength steel with a thickness of 6-20mm; the height of the arc-shaped steel plate covers the upper and lower ranges of 500-800mm above and below the connection between the column and the beam member; the bottom steel plate, side steel plate, and top steel plate of the beam are made of Q355 or Q460 high-strength steel with a thickness of 5-18mm; the length of the bottom steel plate extends to the core area of ​​the beam support and exceeds the edge of the support by 50-100mm.

[0009] Preferably, in step (4), the drilling distance between the arc-shaped steel plate and the cylindrical surface is 150-300mm; the drilling distance between the beam surface and the steel plate is 120-250mm.

[0010] Preferably, the thickness of the interface treatment agent in step (5) is 0.2–0.3 mm; the interface treatment agent is an epoxy treatment agent or a polymer cement slurry. The epoxy treatment agent includes the following chemical components: epoxy resin E-44 (50-55%), diluent xylene (20-25%), γ-aminopropyltriethoxysilane coupling agent (5-8%), reinforcing agent nano-SiO2 (10-15%), and pigment (≤2%).

[0011] Preferably, the step (5) of attaching the steel plate to the surface of the beam is to attach the bottom steel plate, the side steel plate, and the top steel plate to the bottom, side, and top of the beam respectively, and fix them to the chemical anchors with nuts. The end of the side steel plate is aligned with the cylindrical arc steel plate and welded and fixed. A reinforcing gusset plate is installed in the core area of ​​the beam-column joint and welded firmly to the side steel plate and the cylindrical arc steel plate.

[0012] Preferably, the triangular prism collaborative support unit in step (6) is prefabricated from Q460 grade high-strength steel, and its cross-section is an isosceles triangle with a vertex angle of 30°~60°; the length of the triangular prism collaborative support unit is consistent with the width of the beam, and the height is determined according to the distance between the bottom of the beam and the surface of the cylinder, so that it can completely fill the gap between the bottom of the beam and the cylinder after installation; welding bevels are opened on both mating surfaces of the triangular prism collaborative support unit.

[0013] Another objective of this invention is to provide a reinforcement structure suitable for the collaborative operation of externally encased steel beam-column joints, comprising a cylindrical steel-encased reinforcement unit, a beam-encased steel reinforcement unit, and a triangular prism collaborative support unit; the cylindrical steel-encased reinforcement unit is wrapped around the outside of the building column, forming an integrated load-bearing structure with the column; the beam-encased steel reinforcement unit is fitted and fixed to the surface of adjacent beam members on both sides of the column, and extends to the bottom of the beam; the triangular prism collaborative support unit is disposed between the bottom of the beam member and the column, with both ends fixedly connected to the beam-encased steel reinforcement unit and the cylindrical steel-encased steel reinforcement unit, respectively.

[0014] The technical solution of the present invention has the following beneficial effects: The cylindrical steel-clad reinforcement unit of this invention is composed of at least two arc-shaped steel plates joined together. The curvature of the arc-shaped steel plates matches the outer curvature of the cylinder, ensuring a tight fit with the cylinder surface. The arc-shaped steel plates are made of Q355 or Q460 high-strength steel, and the thickness of the steel plates is determined according to the design load-bearing requirements of the cylinder, ranging from 6 to 20 mm. The height of the arc-shaped steel plates covers a range of 500-800 mm above and below the connection between the cylinder and the beam component, ensuring that the reinforcement range covers the core stress area of ​​the node.

[0015] Several anchor bolt holes are set on the inner side of the curved steel plate, and chemical anchor bolts or expansion bolts are pre-embedded in the concrete base of the corresponding cylinder. The spacing of the anchor bolts is 150-300mm to ensure the connection strength between the steel plate and the cylinder. The splice of adjacent curved steel plates is made by full penetration welding, and the weld height is not less than the thickness of the steel plate. After welding, the weld is ground to avoid stress concentration. In addition, an interface treatment agent is applied between the surfaces of the curved steel plate and the cylinder. The interface treatment agent is an epoxy treatment agent or polymer cement slurry with a thickness of 0.2-0.3mm to fill the tiny gaps between the two and enhance the bonding performance.

[0016] The steel-clad beam reinforcement unit of this invention includes a bottom steel plate, side steel plates, and a top steel plate. Depending on the stress characteristics of the beam, these plates can be selectively placed in the tension zone, compression zone, or sides of the beam. The bottom, side, and top steel plates are all made of high-strength steel of the same material as the cylindrical steel-clad beam reinforcement unit, with a thickness of 5-18 mm. The specific thickness is calculated and determined based on the beam's bending and shear resistance design requirements.

[0017] The bottom steel plate extends to the core area of ​​the beam's support and beyond the support edge by 50-100mm, ensuring that the reinforcement covers the critical load-bearing section of the beam. The side steel plates cover the entire cross-sectional height of the beam, with the same length as the bottom steel plate. The top steel plate is located in the compression zone of the beam, with the same length as the bottom steel plate. Anchor bolt holes are drilled in the bottom, side, and top steel plates, with a spacing of 120-250mm. Chemical anchor bolts are pre-embedded in the concrete base layer of the beam to achieve mechanical anchoring between the steel plates and the beam.

[0018] The connection between the beam-encased steel reinforcement unit and the cylindrical steel reinforcement unit is fixed by welding. The end of the beam side steel plate extends to the surface of the arc-shaped steel plate of the cylindrical steel reinforcement unit, with a welding length of not less than 100mm. In the core area of ​​the beam-column connection node, a reinforcing gusset plate is added. The reinforcing gusset plate is welded and fixed to both the beam side steel plate and the cylindrical arc-shaped steel plate to further enhance the connection strength.

[0019] The triangular prism collaborative support unit of this invention is prefabricated using Q460 grade high-strength steel. Its cross-section is an isosceles triangle, and the apex angle is determined based on the diameter of the cylinder and the height of the beam bottom, ranging from 30° to 60°. This ensures that the two sides of the triangular prism can fit tightly against the beam bottom steel plate and the cylindrical arc-shaped steel plate, respectively. The length of the triangular prism collaborative support unit is the same as the width of the beam, and the height is determined based on the distance between the beam bottom and the cylinder surface. After installation, it can completely fill the gap between the beam bottom and the cylinder.

[0020] Welding bevels are made on both mating surfaces of the triangular prism collaborative support unit. During installation, the corresponding positions on the beam bottom steel plate and the cylindrical arc steel plate are first leveled. Then, the triangular prism collaborative support unit is positioned and fitted, and a firm connection with the beam bottom steel plate and the cylindrical arc steel plate is achieved through bevel welding. Several reinforcing ribs are set in the middle of the triangular prism collaborative support unit. The reinforcing ribs are fixed to the triangular prism body by welding to enhance the buckling resistance of the support unit. Detailed Implementation

[0021] Example 1 A reinforcement method suitable for the coordinated operation of external steel beam-column joints, comprising the following steps: (1) Conduct a survey of the cylindrical and beam components in the reinforcement area of ​​the external steel beam-column joint; verify the component size, concrete strength grade and other parameters, determine the technical parameters such as steel plate thickness, anchor bolt specifications, and triangular prism size according to the design requirements, and prepare a detailed construction plan; (2) Use an angle grinder and a wire brush to remove rust from the cylindrical surface to a rust removal grade of Sa2.5; then use a grinding wheel to grind and level the surface, with a surface flatness error of no more than 2mm / m; finally, use high-pressure air to blow clean the surface and remove dust and debris. (3) Grind the surface of the beam component to remove the surface laitance and debris of the concrete, grind to a solid concrete base, and the surface flatness error is not greater than 2mm / m; remove dust from the ground surface to ensure that the surface is dry and clean; (4) Prepare an arc-shaped steel plate according to the diameter and design height of the cylinder, and drill holes on the arc-shaped steel plate and the surface of the cylinder; cut and process the steel plate according to the size of the beam component, and drill holes on the surface of the beam and the steel plate; inject chemical anchoring adhesive into the drilled holes on the surface of the cylinder and the surface of the beam, and insert chemical anchor bolts. After the combination is stable, proceed with subsequent construction; the steel plate includes the bottom steel plate of the beam, the side steel plate of the beam, the top steel plate of the beam and the reinforcing gusset plate; The drilling design method is as follows: Regarding the drilling diameter, the chemical anchor hole is... 22mm (compatible with M20 anchor bolts), steel plate bolt holes are 24mm (with a 2mm gap); the drilling depth is 15d (d is the anchor bolt diameter), i.e., 300mm (M20 anchor bolt); specifically, in the embodiment, the cylinder diameter D=800mm, the beam height H=600mm: the drilling spacing and number are evenly distributed around the cylinder (every 1m height) at a spacing of 150mm, 16 per row, 16 per meter; the bottom steel plate of the beam is spaced 300mm along the beam length, 3 per meter; the side steel plate of the beam is vertically spaced (starting from 200mm from the column edge) at a spacing of 400mm, 2 per meter (beam height 600mm); the chemical anchoring adhesive is Fischer FIS EM390 S; the chemical anchor bolt is Hilti HY-200-R M20×300 (5.8 grade carbon steel hot-dip galvanized). (5) Apply an interface treatment agent to the surface of the cylinder, attach the arc-shaped steel plate to the surface of the cylinder, and fix it to the chemical anchor bolts with nuts; apply an interface treatment agent to the surface of the beam, attach the bottom steel plate, side steel plate, and top steel plate of the beam to the bottom, side, and top positions of the beam respectively, and fix them to the chemical anchor bolts with nuts; align the ends of the side steel plate with the arc-shaped steel plate of the cylinder and weld them in place; install reinforcing gusset plates in the core area of ​​the beam-column joint, with a cross-grid spacing of 500×500mm, each... Four square meters of steel plates are welded firmly to the side steel plates of the beam and the cylindrical arc-shaped steel plates; the joints of adjacent arc-shaped steel plates and steel plates are welded and ground; the interface treatment agent is an epoxy treatment agent, and its specific chemical composition is epoxy resin E-44 (53.5%), diluent xylene (25%), γ-aminopropyltriethoxysilane coupling agent (5%), reinforcing agent nano-SiO2 (15%), and pigment (1.5%). The coating thickness of the interface treatment agent is 0.2–0.3 mm. (6) Design a triangular prism support unit according to the beam bottom height and the cylinder diameter, and weld reinforcing ribs on the triangular prism support unit; the triangular prism support unit is designed as an isosceles right triangle with a right angle side length of 200mm (height is the same as the width of the beam bottom steel plate, ≥250mm), and the material is Q235B steel plate (thickness 12mm); the reinforcing rib is ∠75×6 angle steel, welded at the midpoint of the 45° hypotenuse; the welding adopts bevel welding (angle 60°), the weld height hf=8mm, and the welding is continuous along the entire length; the two mating surfaces of the triangular prism support unit are tightly mated to the beam bottom steel plate and the cylindrical arc steel plate respectively, and bevel welding is performed to obtain the reinforced structure.

[0022] A comprehensive inspection of the reinforced structure is conducted, including indicators such as steel plate fit, weld quality, anchor bolt tightness, and stability of the triangular prism support, to ensure compliance with design and specification requirements. Load tests or non-destructive testing are carried out to verify the load-bearing capacity and synergistic stress effect of the reinforced structure. Construction is completed after acceptance.

Claims

1. A reinforcement method suitable for the coordinated operation of externally-enclosed steel beam-column joints, characterized in that, Includes the following steps: (1) Conduct an investigation of the cylindrical and beam components in the reinforced area of ​​the external steel beam-column joint; (2) Remove rust and grind the cylindrical surface, then blow it clean to remove dust and debris from the surface; (3) Grind the surface of the beam component to remove the surface laitance and debris of the concrete, grind to a solid concrete base, and the surface flatness error is not greater than 2mm / m; remove dust from the ground surface to ensure that the surface is dry and clean; (4) Prepare an arc-shaped steel plate according to the diameter and design height of the cylinder, and drill holes on the arc-shaped steel plate and the surface of the cylinder; cut and process the steel plate according to the size of the beam component, and drill holes on the surface of the beam and the steel plate; inject chemical anchoring adhesive into the drilled holes on the surface of the cylinder and the surface of the beam, and insert chemical anchor bolts. After the combination is stable, proceed with subsequent construction; the steel plate includes the bottom steel plate of the beam, the side steel plate of the beam, the top steel plate of the beam and the reinforcing gusset plate; (5) Apply an interface treatment agent to the surface of the cylinder, attach the arc-shaped steel plate to the surface of the cylinder, and fix it to the chemical anchor bolt with a nut; apply an interface treatment agent to the surface of the beam, attach the steel plate to the surface of the beam, and fix it to the chemical anchor bolt with a nut; weld and grind the joints of adjacent arc-shaped steel plates and steel plates. (6) Design a triangular prism support unit according to the beam bottom height and the cylinder diameter, and weld reinforcing ribs on the triangular prism support unit; tightly fit the two mating surfaces of the triangular prism support unit with the beam bottom steel plate and the cylindrical arc steel plate respectively, and perform bevel welding to obtain a reinforced structure and complete the construction.

2. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, The rust removal treatment in step (2) achieves a rust removal grade of Sa2.5; the grinding and leveling ensures that the surface flatness error is no greater than 2mm / m.

3. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, The chemical anchoring adhesive used in step (4) has a compressive strength ≥100MPa, a tensile strength ≥30MPa, and an applicable temperature range of -40℃ to 80℃.

4. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, The design value of the tensile bearing capacity of the chemical anchor in step (4) is ≥150kN, and the design value of the shear bearing capacity is ≥120kN.

5. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, The arc-shaped steel plate in step (4) is made of Q355 or Q460 high-strength steel with a thickness of 6-20mm; the height of the arc-shaped steel plate covers the upper and lower ranges of 500-800mm above and below the connection between the column and the beam member; the bottom steel plate, side steel plate, and top steel plate of the beam are made of Q355 or Q460 high-strength steel with a thickness of 5-18mm; the length of the bottom steel plate of the beam extends to the core area of ​​the support of the beam and exceeds the edge of the support by 50-100mm.

6. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, In step (4), the drilling spacing between the arc-shaped steel plate and the cylindrical surface is 150-300mm; the drilling spacing between the beam surface and the steel plate is 120-250mm.

7. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, The thickness of the interface treatment agent in step (5) is 0.2–0.3 mm, and the interface treatment agent is an epoxy treatment agent or a polymer cement slurry.

8. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, Step (5) involves attaching the steel plate to the beam surface by attaching the bottom steel plate, side steel plate, and top steel plate to the bottom, side, and top of the beam, respectively, and fixing them to the chemical anchors with nuts. The ends of the side steel plate are aligned with the cylindrical arc steel plate and welded together. A reinforcing gusset plate is installed in the core area of ​​the beam-column joint and welded firmly to the side steel plate and the cylindrical arc steel plate.

9. The reinforcement method for the coordinated operation of externally enclosed steel beam-column joints according to claim 1, characterized in that, The triangular prism collaborative support unit in step (6) is prefabricated using Q460 grade high-strength steel. Its cross-section is an isosceles triangle with a vertex angle of 30°~60°. The length of the triangular prism collaborative support unit is consistent with the width of the beam, and the height is determined according to the distance between the bottom of the beam and the surface of the cylinder. After installation, it can completely fill the gap between the bottom of the beam and the cylinder. Welding bevels are opened on both mating surfaces of the triangular prism collaborative support unit.

10. The reinforced structure obtained by the reinforcement method applicable to the coordinated work of external steel beam-column joints according to claim 1, characterized in that, The structure includes a cylindrical steel-clad reinforcement unit, a beam steel-clad reinforcement unit, and a triangular prism collaborative support unit. The cylindrical steel-clad reinforcement unit wraps around the outside of the building's cylindrical column, forming an integrated load-bearing structure with the column. The beam steel-clad reinforcement unit is fitted and fixed to the surfaces of adjacent beam members on both sides of the column and extends to the bottom of the beam. The triangular prism collaborative support unit is located between the bottom of the beam member and the column, with both ends fixedly connected to the beam steel-clad reinforcement unit and the cylindrical steel-clad reinforcement unit, respectively.