A reinforced structure of a staggered floor joint of a composite column-beam and a construction method thereof

Abstract

This invention belongs to the field of beam-column staggered joint reinforcement technology, and discloses a composite column-beam staggered joint reinforcement structure and construction method. A reinforced frame is formed by integrally connecting the outer steel frame of the column and the outer steel frame of the beam. L-shaped steel plates with triangular ribs are installed on the upper side of the higher beam and the lower side of the lower beam at the root of the staggered joint, and channel steel plates with triangular ribs are installed on the lower side of the higher beam and the upper side of the lower beam. The beam steel plates are then attached to the beam body and serve as horizontal extensions of the ribbed steel plates. This reinforcement structure effectively adapts to the special stress of staggered joints, avoids brittle failure of the core area of ​​the joint or the beam root under earthquakes, ensures continuous force transmission path, significantly improves seismic ductility and energy dissipation capacity, conforms to the principle of strong joints and weak components, and reduces on-site wet work, achieving minimally invasive reinforcement with low disturbance, fundamentally solving the problem of insufficient seismic toughness of staggered joints.

Description

Technical Field

[0001] This invention belongs to the field of beam-column staggered joint reinforcement technology, and particularly relates to a composite beam-column staggered joint reinforcement structure and construction method. Background Technology

[0002] With the continuous and in-depth advancement of urban renewal, upgrading the seismic safety of existing high-rise buildings has become a key task in the field of building renovation. Many high-rise buildings constructed in earlier years, to accommodate diverse functional needs, commonly adopted a staggered structure. Due to the abrupt changes in structural geometry at the beam-column joints, these buildings experience significant stress concentration, making them highly susceptible to becoming weak points in the overall structure under seismic loads. To ensure that older staggered buildings meet current seismic design codes and eliminate structural safety hazards, specialized reinforcement treatment of the staggered beam-column joints is necessary. Among these methods, external steel reinforcement technology, with its advantages of convenient and efficient construction and significant improvement in structural bearing capacity, is widely used in the reinforcement of beam-column joints in existing buildings and is currently the mainstream technical solution for seismic reinforcement of staggered joints.

[0003] Currently, conventional external steel reinforcement solutions in the industry are designed for standard beam-column joints, often using angle steel with gusset plates for fixed reinforcement. These solutions only improve the bearing capacity of the joint foundation and do not specifically address the complex and unique stress characteristics of staggered joints. Under seismic loading, traditional reinforcement methods are still prone to brittle failure at the beam root or core area of ​​the joint. The core area of ​​staggered joints inherently has complex stress conditions and poor structural ductility; failure in this area will directly interrupt the structural force transmission path, significantly increasing the risk of partial building collapse. This violates the core principle of "strong joints, weak components" in seismic design and fails to meet the current seismic codes' requirements for structural ductility and energy dissipation capacity. Furthermore, traditional external steel reinforcement involves a significant amount of wet work, causing considerable disturbance to the building site and making it difficult to adapt to the actual needs of minor renovations and low-disturbance construction of existing buildings. It cannot fundamentally solve the core reinforcement problems of unreasonable failure modes and insufficient seismic toughness in earthquake-damaged staggered joints.

[0004] It is evident that existing steel reinforcement technologies for staggered beam-column joints suffer from poor specific adaptability, limited seismic reinforcement effects, and insufficient construction adaptability, making it difficult to meet the seismic safety upgrade requirements of existing staggered high-rise buildings. Summary of the Invention

[0005] This invention provides a reinforced structure and construction method for composite column-beam staggered joints. By adopting this reinforced structure, the defects of existing external steel reinforcement technology for staggered beam-column joints, such as poor specific adaptability, limited seismic reinforcement effect, and insufficient construction adaptability, can be solved, and the seismic safety upgrade needs of existing staggered high-rise buildings can be met.

[0006] To achieve the above objectives, the present invention employs the following technical content: A composite column-beam staggered joint reinforcement structure, wherein the composite column-beam staggered joint is formed by a combination of columns and high and low beams, wherein the high and low beams include high beams and low beams; the reinforcement structure includes a steel frame encasing the columns, a steel frame encasing the beams, an L-shaped steel plate with triangular ribs, a channel steel plate with triangular ribs, and a beam steel plate. The steel frame surrounding the column is fixedly assembled to the outside of the column body; The steel frame surrounding the beam is fixedly assembled to the outside of the high and low beams. The outer steel frame of the beam and the outer steel frame of the column are integrally fixed together. The L-shaped steel plate with triangular ribs is assembled and fixed to the upper side of the high beam and the lower side of the low beam at the root of the composite column-beam staggered node, and is fixedly connected to the outer steel frame of the column and the outer steel frame of the beam respectively. The triangular ribbed steel plate is assembled and fixed to the area below the high beam and above the low beam at the root of the composite column-beam staggered node, and is fixedly connected to the outer steel frame of the column and the outer steel frame of the beam respectively. The beam steel plates are fitted and assembled on the outer surface of the high and low beams, and are respectively fixedly connected to the L-shaped steel plate with triangular ribs, the channel steel plate with triangular ribs, and the outer steel frame of the beam; the beam steel plates are respectively used as extensions of the L-shaped steel plate with triangular ribs and the channel steel plate with triangular ribs along the horizontal direction of the beam, and are used to guide the plastic hinge at the beam end to transfer from the beam root to the predetermined area on the outside of the beam.

[0007] Furthermore, the steel frame surrounding the column includes column angle steel and column gusset plates; The column angle steel is vertically arranged along the four corners of the column; the column gusset plate is horizontally fixedly connected between two adjacent column angle steels.

[0008] Furthermore, the steel frame surrounding the beam includes beam angle steel, a first beam gusset plate, a second beam gusset plate, and a third beam gusset plate; The angle steel of the beam is fitted and wrapped around the four corners of the high and low beams, and the angle steel of the beam is fitted along the root of the high and low beams in the length direction; The first beam lacing plate, the second beam lacing plate, and the third beam lacing plate are fixedly connected to the inside of the beam angle steel in a two-way layout. Multiple sets of beam lacing plates and beam angle steel work together to form an overall rigid skeleton structure.

[0009] Furthermore, the L-shaped steel plate with triangular ribs includes an L-shaped steel plate and triangular ribs; The L-shaped steel plate is fixed to the area above the high beam and below the low beam at the root of the staggered node of the composite column-beam; The triangular ribs are fixedly arranged on the inner side of the L-shaped steel plate and are evenly distributed along the length of the L-shaped steel plate. The vertical limbs of the L-shaped steel plate are fitted and fixed to the outer steel frame of the column, and the horizontal limbs of the L-shaped steel plate are fixedly connected to the outer steel frame of the beam.

[0010] Furthermore, the channel steel plate with triangular ribs includes a channel steel plate, triangular ribs, and a flat steel plate; The channel steel plate is fixed to the area below the high beam and above the low beam of the staggered node; Triangular ribs are fixedly assembled on the inner sides of the upper and lower sides of the channel steel plate. The flat steel plate, the channel steel plate, and the triangular rib are fixedly connected to form a closed integral force transmission component. The channel-shaped steel plate is snapped and fixed at the end of the staggered height beam, and is fixedly connected to the outer steel frame of the column and the outer steel frame of the beam respectively.

[0011] Furthermore, the spacing of the triangular ribs is matched with the width of the high and low beams; wherein, the triangular ribs on the inner side of the channel steel plate are arranged close to the inner edge of the channel steel plate, and the remaining triangular ribs are evenly arranged according to the beam width spacing.

[0012] Furthermore, the horizontal leg length of the L-shaped steel plate with triangular ribs satisfies the following relationship:

[0013]

[0014]

[0015] In the formula, The horizontal leg length of the L-shaped steel plate with triangular ribs; l p1 , l p2 These are the calculated values ​​for the lengths of the two sets of plastic hinges, respectively. h 0 represents the effective height of the beam section; z This is the distance from the support at the beam end to the column. for l p1 , l p2 The maximum value in.

[0016] Furthermore, the tensile extension length of the beam steel plate satisfies the following relationship:

[0017] In the formula, The tensile extension length of the steel plate of the beam; This refers to the total thickness of the steel plate being bonded. The design value for the tensile strength of the reinforced steel plate; This is the design value for the bond strength between the steel plate and the concrete; Reserved length for construction.

[0018] Furthermore, grouting material is filled between the steel frame of the column and the column body, and between the steel frame of the beam and the high and low beam bodies.

[0019] A construction method for a composite column-beam staggered joint reinforcement structure, used to assemble the aforementioned composite column-beam staggered joint reinforcement structure, includes: The column angle steel is attached to the four corners of the column and fixed, and the column lacing plate is welded to form the outer steel frame of the column. The angle steel of the beam is wrapped around the high and low beams, and the beam gusset plates are welded to form the outer steel frame of the beam. The root of the outer steel frame of the beam and the outer steel frame of the column are welded together to form a whole reinforcement cage. The triangular ribs are welded onto the L-shaped steel plate and the channel steel plate respectively to obtain the L-shaped steel plate with triangular ribs and the channel steel plate with triangular ribs; the L-shaped steel plate with triangular ribs and the channel steel plate with triangular ribs are positioned at the staggered node of the composite column and beam and welded and fixed to the column angle steel and the beam angle steel respectively. On the high and low beams, beam steel plates are welded along the horizontal direction of the beams. L-shaped steel plates with triangular ribs and grooved steel plates with triangular ribs are welded to the corresponding beam steel plates, so that the beam steel plates serve as extensions of the L-shaped steel plates with triangular ribs and the grooved steel plates with triangular ribs, respectively, to complete the assembly of the overall outer steel system. Grouting material is injected between the steel frame surrounding the column and the column body, and between the steel frame surrounding the beam and the beams of varying heights. Once the grouting material has cured to the design strength, the reinforcement construction of the composite column-beam staggered joint is completed. Compared with existing technologies, this invention has the following advantages: This invention provides a reinforced structure for composite column-beam staggered joints. A reinforced frame is formed by integrally connecting the outer steel skeleton of the column and the outer steel skeleton of the beam. L-shaped steel plates with triangular ribs are installed on the upper side of the higher beam and the lower side of the lower beam at the root of the staggered joint, while channel-shaped steel plates with triangular ribs are installed on the lower side of the higher beam and the upper side of the lower beam. These steel plates are then attached to the beam body and serve as horizontal extensions of the ribbed steel plates. This reinforced structure significantly enhances the shear and bending bearing capacity of the joint core area using the triangular ribbed steel plates. Simultaneously, the steel plates guide the plastic hinge at the beam end from the stress-complex beam root area to a predetermined position on the outer side of the beam body, thereby changing the stress distribution. This allows the structure to effectively adapt to the special stresses of the staggered joint, avoiding brittle failure of the joint core area or beam root under earthquakes, ensuring continuous force transmission path, significantly improving seismic ductility and energy dissipation capacity, conforming to the principle of strong joints and weak components, and reducing on-site wet work. It achieves minimally invasive reinforcement with low disturbance, fundamentally solving the problem of insufficient seismic toughness of staggered joints.

[0020] This invention also provides a construction method for reinforcing composite column-beam staggered joints. This method involves first assembling and welding the angle steel and connecting plates of the columns and beams to form a reinforced cage. Then, L-shaped and channel-shaped steel plates with triangular ribs are welded and installed at key joint locations, and welded to the beam steel plates to form extension limbs. Finally, grout is injected to complete the reinforcement. This method first constructs a complete external steel load-bearing system through modular dry welding operations, enabling the ribbed steel plates to precisely strengthen the stress concentration areas of the joint and guide the transfer of plastic hinges. Finally, grouting achieves synergy with the original structure. This method significantly reduces on-site wet work and construction disturbance, achieving precise and rapid reinforcement of complex staggered joints. It not only effectively improves the seismic ductility and energy dissipation capacity of the joint, ensuring compliance with the principle of strong joints and weak components, but also highly adaptable to the needs of minimally invasive renovations of existing buildings. Attached Figure Description

[0021] Figure 1 This is a structural schematic diagram of a composite column-beam staggered joint reinforcement structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the column external steel frame structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the beam-encased steel frame structure provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of an L-shaped steel plate with triangular ribs provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a steel plate with triangular ribs provided in an embodiment of the present invention; Figure 6 Provided for embodiments of the present invention Figure 1 Enlarged structural diagram at point A in the middle; Figure 7 The load-displacement skeleton curve is provided for an embodiment of the present invention.

[0022] Figure label: 1. Column external steel frame; 2. Beam external steel frame; 3. L-shaped steel plate with triangular ribs; 4. Channel steel plate with triangular ribs; 5. Beam steel plate; 6. Column angle steel; 7. Column lacing plate; 8. Beam angle steel; 9. First beam lacing plate; 10. Second beam lacing plate; 11. Third beam lacing plate; 12. L-shaped steel plate; 13. Triangular ribs; 14. Channel steel plate; 15. Flat steel plate. Detailed Implementation

[0023] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] like Figure 1 As shown, this embodiment provides a composite column-beam staggered joint reinforcement structure, which is applied to the seismic reinforcement of existing building beam-column staggered joints. The composite column-beam staggered joint is formed by a combination of columns and high and low beams. The high and low beams specifically include high beams and low beams. The overall reinforcement structure is an external steel system, specifically including a column external steel frame 1, a beam external steel frame 2, an L-shaped steel plate with triangular ribs 3, a channel steel plate with triangular ribs 4, and a beam steel plate 5. All steel materials are Q235B, which can work together with the original node concrete structure to bear the load.

[0028] Among them, the column outer steel frame 1 is fixedly assembled to the outside of the column, and the beam outer steel frame 2 is fixedly assembled to the outside of the high and low beams, and the beam outer steel frame 2 and the column outer steel frame 1 are integrally fixedly connected to form a closed integral reinforced cage foundation structure; the L-shaped steel plate 3 with triangular ribs is assembled and fixed to the upper side of the high beam and the lower side of the low beam at the root of the composite column-beam staggered node, and is fixedly connected to the column outer steel frame 1 and the beam outer steel frame 2 respectively; the channel steel plate 4 with triangular ribs is assembled and fixed to the lower side of the high beam and the upper side of the low beam at the root of the composite column-beam staggered node, and is also fixedly connected to the column outer steel frame 1 and the beam outer steel frame 2 respectively; Figure 6As shown, the beam steel plate 5 is arranged on the upper and lower sides of the beam body and is fitted to the outer surface of the high and low beams. It is fixedly connected to the L-shaped steel plate 3 with triangular ribs, the channel steel plate 4 with triangular ribs, and the outer steel frame 2 of the beam. The beam steel plate 5 can be used as an extension of the L-shaped steel plate 3 with triangular ribs and the channel steel plate 4 with triangular ribs along the horizontal direction of the beam body to guide the plastic hinge at the beam end to transfer from the beam root to a predetermined area on the outside of the beam body. Explained, this embodiment adapts the irregular structural characteristics of the high and low beams of the staggered node to multiple sets of steel components in a partitioned manner, realizing all-round wrapping and reinforcement of the core area of ​​the node. The integrated and fixed steel frame structure greatly improves the overall stiffness and integrity of the staggered node. At the same time, relying on the extension structure of the beam steel plate 5, the stress mode at the beam end is precisely changed, avoiding concentrated failure at the beam root from the root, and effectively improving the seismic ductility and overall structural stability of the node.

[0029] As another preferred embodiment, such as Figure 2 As shown, the steel frame 1 encasing the column includes column angle steel 6 and column lacing plates 7. The column angle steel 6 is vertically arranged along the four corners of the column, and the column lacing plates 7 are horizontally fixedly connected between two adjacent column angle steel 6. The column lacing plates 7 are only arranged in the beam-column joint area. Specifically, the vertically arranged column angle steel 6 and the horizontally arranged column lacing plates 7 cooperate with each other to form a complete ring-shaped hoop structure in the column joint area. Explained, this ring-shaped hoop structure can effectively constrain the concrete in the joint area, efficiently transfer and disperse the concentrated load transferred from the beam end to the joint through the ring-shaped hoop effect, significantly share the stress in the core area of ​​the joint, avoid stress concentration, cracking and damage in the column joint area, stabilize the mechanical properties of the joint area, and ensure reliable force transmission connection between the column and the beam.

[0030] As another preferred embodiment, such as Figure 3 As shown, the outer steel frame 2 of the beam includes beam angle steel 8, first beam lacing plate 9, second beam lacing plate 10, and third beam lacing plate 11. The beam angle steel 8 is fitted and wrapped around the upper and lower edges and side walls of the high and low beams, fully covering the outer contour of the beam. The first beam lacing plate 9, second beam lacing plate 10, and third beam lacing plate 11 are fixedly connected to the inner side of the beam angle steel 8 in a two-way layout. The multiple sets of beam lacing plates and the beam angle steel 8 work together to form an integral rigid frame structure. This can be explained by the two-way layout of multiple sets of beam lacing plates, which can provide multi-directional constraint and fixation for the beam angle steel 8, completely solving the defects of insufficient stiffness and easy deformation of a single angle steel covering, comprehensively improving the shear and bending bearing capacity of the high and low beams, while ensuring the integrity and structural rigidity of the outer steel frame 2 itself, providing a stable foundation for the subsequent assembly and fixing of various reinforcing steel plates.

[0031] As another preferred embodiment, such as Figure 4As shown, the L-shaped steel plate 3 with triangular ribs includes an L-shaped steel plate 12 and triangular ribs 13. The L-shaped steel plate 12 is fixed to the upper side of the high beam and the lower side of the low beam at the root of the staggered node of the composite column-beam. The triangular ribs 13 are fixedly arranged on the inner side of the L-shaped steel plate 12 and are evenly arranged along the length of the L-shaped steel plate 12. The vertical limbs of the L-shaped steel plate 12 are fully welded to the outer steel frame 1 of the column. The horizontal limbs of the L-shaped steel plate 12 are reliably fixed to the outer steel frame 2 of the beam. The arrangement spacing of the triangular ribs 13 is matched with the width of the high and low beams. Explained, the L-shaped steel plate 12 is adapted to the irregular spatial structure of the upper side of the high beam and the lower side of the low beam at the staggered node, so as to realize the fit and reinforcement of the transition area of ​​the beam-column node. The triangular ribs 13 evenly arranged on the inner side can greatly improve the bending stiffness of the L-shaped steel plate 12 itself and the overall structural strength, optimize the force transmission path of the steel plate and improve the force transmission efficiency. At the same time, in conjunction with the overall steel frame structure, it initially guides the plastic hinge at the beam end to move outward, and relieves the stress pressure on the beam root.

[0032] As another preferred embodiment, such as Figure 5 As shown, the channel steel plate 4 with triangular ribs includes a channel steel plate 14, triangular ribs 13, and a flat steel plate 15. The channel steel plate 14 is fixed to the area below the high beam and above the low beam at the staggered node. Triangular ribs 13 are fixedly assembled on the inner surfaces of both the upper and lower sides of the channel steel plate 14. The flat steel plate 15 is fixedly connected to the channel steel plate 14 and the triangular ribs 13 to form a closed integral force transmission component. The channel structure end of the channel steel plate 14 is snapped and fixed to the end of the staggered high and low beams, and is fixedly connected to the outer steel frame 1 of the column and the outer steel frame 2 of the beam, respectively. Specifically, the triangular ribs 13 on the inner side of the channel steel plate 14 are arranged close to the inner edge of the channel steel plate 14, and the remaining triangular ribs 13 are evenly arranged according to the beam width spacing. Explained, the slotted snap-fit ​​structure can achieve precise positioning and coverage of the ends of high and low beams, adapting to the special structural form of staggered nodes where high and low beams intersect. The closed integral force transmission component completely solves the problem of force transmission discontinuity and weak stress in the middle area of ​​the staggered node. The triangular ribs 13 arranged on the upper and lower sides further strengthen the structural rigidity of the slotted steel plate 14, ensuring the continuous transfer of load between high and low beams and between beams and columns, and comprehensively strengthening the weak stress area of ​​the core area of ​​the node.

[0033] As another preferred embodiment, grouting material is used to fill the gaps between the column outer steel frame 1 and the column body, and between the beam outer steel frame 2 and the high and low beam bodies. Explained, the grouting material can completely fill the minute gaps between the steel frame and the original concrete structure, eliminating the separation gaps in the steel-concrete structure, significantly improving the interfacial bond strength between the steel and concrete, effectively avoiding the problem of relative slippage between the steel frame and concrete under load, achieving integrated and coordinated stress distribution between the reinforced steel components and the original building structure, and maximizing the load-bearing and seismic performance of the reinforcement system.

[0034] As another preferred embodiment, the horizontal leg length of the L-shaped steel plate 3 with triangular ribs satisfies the preset calculation formula:

[0035]

[0036]

[0037] In the formula, The horizontal leg length of the L-shaped steel plate 3 with triangular ribs; l p1 , l p2 These are the calculated values ​​for the lengths of the two sets of plastic hinges, respectively. h 0 represents the effective height of the beam section; z This is the distance from the support at the beam end to the column. for l p1 , l p2 The maximum value in.

[0038] Explained, by combining the distribution pattern of plastic hinges, beam section parameters, and support force distance to limit the horizontal leg length, the stress requirements of staggered beams of different specifications can be precisely matched. This ensures that the reinforcement coverage and force transmission length of the L-shaped steel plate 3 with triangular ribs accurately match the design requirements, ensuring that the outward displacement of the plastic hinge is controllable and standardized, and guaranteeing the stability and accuracy of the reinforcement effect from the structural dimension level. The L-shaped steel plate of this size can completely cover the entire length of the plastic hinge at the beam end, forming an effective constraint on the plastic hinge area across the entire range, effectively limiting the propagation of cracks at the beam end, and improving the ductility and seismic energy dissipation capacity of the joint. At the same time, it can minimize the opening size of the floor slab in the joint area, reduce the weakening effect of the opening on the overall integrity of the floor slab, take into account both the building's functionality and the aesthetics of the interior space, reduce the amount of steel and concrete used, and reduce construction and subsequent repair costs.

[0039] As another preferred embodiment, this reinforcement structure adopts a reinforcement system combining continuous external angle steel and locally tensioned steel plates at the beam root. The extension length of the tensioned steel plate at the welded joints of the beam steel plate 5 with the upper and lower angle steels at the beam root satisfies the following design formula:

[0040] In the formula, The extension length of the tension steel plate of beam steel plate 5; This refers to the total thickness of the steel plate being bonded. Design value for the tensile strength of reinforced steel plates; This is the design value for the bond strength between the steel plate and the concrete; Reserved length for construction.

[0041] The first term of the above formula The theoretical anchorage length for traditional steel plate bonding reinforcement, based on interfacial bond strength, is applicable only if the steel plate load is entirely transferred through the bond force. In this embodiment, the beam steel plate 5 is rigidly connected to the continuous outer angle steel by welding, and the main force transmission path is "beam steel plate → continuous outer angle steel → node core area". Furthermore, the bonding strength of the grout is significantly lower than that of the epoxy resin structural adhesive, resulting in insufficient safety reserve for the theoretical bond anchorage length. Therefore, the actual extension length of the steel plate in this system is determined by the minimum anchorage length at the end. control.

[0042] This design is used to meet the structural requirements of the "Code for Design of Strengthening Concrete Structures," to dissipate stress concentration at the beam root, and to prevent the grout at the steel plate ends from splitting and debonding at the interface. In this embodiment... The minimum value of 200mm is taken as a necessary condition for reinforcement safety.

[0043] Based on this, and considering the test failure results, the initial total length of the beam steel plate 5 was arranged within the range of 1 / 4 to 1 / 3 of the beam length. At the same time, considering that the L-shaped stiffening plate at the beam root overlaps with the beam steel plate 5 in a certain range, in order to ensure the structural rationality and stress coordination of the reinforcement system and to avoid local stress concentration caused by the welding overlap of the steel plate and the stiffening plate, the length of the overlapping section at the beam root was deducted, and the actual design length of the beam steel plate was finally determined.

[0044] Explained, this calculation formula combines the mechanical properties of the steel plate itself with the bonding performance of steel-concrete to limit the extension length. This can effectively avoid insufficient force transmission and failure of plastic hinge transfer caused by the steel plate being too short, or material waste and sudden changes in local stiffness caused by the steel plate being too long. It accurately ensures the plastic hinge guiding function and structural stress balance of the beam steel plate 5.

[0045] In this embodiment, all steel component connections of the above-mentioned composite column-beam staggered node reinforcement structure are fully welded to ensure tight connections and integrated stress distribution among components. Simultaneously, a dedicated construction method is used to complete the overall structural assembly. The specific construction process is as follows: First, the surface of the composite column-beam staggered joint area is cleaned, ground smooth and wiped clean to thoroughly remove loose aggregate and dust from the concrete surface. Then, epoxy resin adhesive is used to repair the original cracks in the concrete to complete the joint pretreatment work. Subsequently, all steel components are prefabricated according to the design dimensions, and the surface of the components is treated with rust removal and anti-corrosion to ensure the quality of the components leaving the factory. During construction, the column angle steel 6 is first fixed to the four corners of the column, and the column lacing plate 7 is welded to form an integrated column outer steel frame 1. Then, the beam angle steel 8 is wrapped around the high and low beams, and the first beam lacing plate 9, the second beam lacing plate 10, and the third beam lacing plate 11 are welded to form the beam outer steel frame 2. The root of the beam outer steel frame 2 is welded and fixed to the column outer steel frame 1 to form an overall reinforced cage structure. Next, the triangular rib 13 is welded onto the L-shaped steel plate 12 and the channel steel plate 14 respectively, and the L-shaped steel plate 3 with triangular rib and the channel steel plate 4 with triangular rib are prefabricated. The two sets of reinforcing steel plates are precisely positioned to the corresponding design positions of the composite column-beam staggered node, and welded and fixed to the column angle steel 6 and the beam angle steel 8 respectively. Then, beam steel plates 5 are welded to the outside of the high and low beams along the horizontal direction of the beams. L-shaped steel plates 3 with triangular ribs and grooved steel plates 4 with triangular ribs are respectively welded to the corresponding beam steel plates 5 on all four sides, so that the beam steel plates 5 can be stably used as horizontal extensions of the two types of reinforcing steel plates, and the assembly of the overall outer steel system is completed. In this way, the plastic hinge can be further transferred to the outside of the beam steel plates 5 by welding the beam steel plates 5. Finally, grout is evenly injected between the outer steel frame 1 of the column and the column body, and between the outer steel frame 2 of the beam and the high and low beam bodies, ensuring that the grout is full and without gaps. After the grout has cured to the design strength, the entire reinforcement construction of the composite column-beam staggered joint is completed.

[0046] Explained, this construction method adopts a step-by-step standardized operation mode of pretreatment, component prefabrication, overall welding, and grouting curing. The on-site construction process is simple and has little disturbance, making it suitable for the renovation of existing buildings. Factory prefabrication of components can ensure component accuracy, and on-site full welding and grouting processes can ensure the integrity of the reinforcement system and the synergistic stress effect of steel and concrete. The construction cycle is short and the forming quality is high. After reinforcement, it can effectively optimize the node failure mode, significantly improve the overall seismic performance and structural durability of the staggered node, and meet the use requirements for safety upgrade of damaged buildings.

[0047] To verify the reinforcement effect of the reinforced structure provided in this embodiment, a specific destructive experiment was also conducted. The specific implementation process is as follows: Three specimens were designed and fabricated for this experiment to compare the seismic performance of joints with different reinforcement methods. The specific design of each specimen is as follows: Specimen JD-1: A benchmark specimen without any reinforcement measures.

[0048] Specimen JGJD-1: Specimen reinforced with external steel sections and beam end steel plates.

[0049] Specimen JGJD-2: Specimen using the reinforcement structure provided in this embodiment, namely the combined reinforcement scheme of outer steel section + 180mm long L-shaped plate + beam end steel plate.

[0050] The failure phenomena of JD-1 specimen are as follows: This specimen serves as a baseline comparison specimen without any reinforcement measures. Through low-cycle repeated loading tests, failure was concentrated in the beam root region, where a plastic hinge formed. Dense bending cracks on the beam surface extended towards the mid-span. In the plastic hinge region, the concrete cracked, and local debris fell off. The longitudinal reinforcement in the beam underwent plastic deformation but did not fracture. The column and joint core area remained relatively intact, with only a few minor surface cracks and no shear failure.

[0051] The failure phenomena of the JGJD-1 specimen are as follows: This specimen was reinforced using traditional external steel cladding and beam end steel plates. Compared to the unreinforced specimen, the failure area was still concentrated in the beam root region; bending cracks on the beam surface extended towards the mid-span, concrete cracking and local debris fallout occurred in the plastic hinge area, and the longitudinal reinforcement inside the beam underwent plastic deformation; the external angle steel and the connecting plate worked together to bear the load, without obvious buckling, debonding or connection failure, and the core area of ​​the column and joint remained intact, with only a few minor surface cracks and no shear failure.

[0052] The failure phenomena of the JGJD-2 specimen are as follows: This specimen uses the reinforcement structure provided in this embodiment, namely, a combined reinforcement scheme of external steel cladding + 180mm long L-shaped plate + beam end steel plate. The beam mainly exhibits bending failure, with the failure area far from the column surface. Plastic hinges are formed in the pre-defined area of ​​the beam body, i.e., outside the beam steel plate. Bending cracks on the beam surface are concentrated in the plastic hinge area. No failure occurred at the beam root. The concrete cracked without severe crushing. The external steel cladding system showed good synergistic stress distribution, with no buckling, debonding, or connection failure. The column and the core area of ​​the nodes remained intact, with only a few minor cracks appearing on the surface.

[0053] Through experimental comparison, the skeleton curve is as follows: Figure 7As shown, a comparison of the load-displacement skeleton curves reveals that in the initial elastic stage of loading, the initial stiffness of the unreinforced original specimen JD-1 and the specimen JGJD-1 reinforced only with external steel sections and beam end plates are similar. This reinforcement scheme does not significantly improve the initial stiffness of the joint. However, the initial stiffness of the specimen JGJD-2, reinforced with the 180mm L-shaped plate combination of this invention, is significantly improved. This indicates that the L-shaped plate structure of this invention can effectively enhance the lateral deformation resistance of the joint before the component enters the elasto-plastic stage. After entering the elasto-plastic stage, the slope of the rising segment of the skeleton curve of the original specimen JD-1 decreases rapidly, and the stiffness degradation is obvious. The stiffness degradation rate of both types of reinforced specimens is significantly slowed down. The ultimate bearing capacity of both specimens is higher than that of JD-1. Among them, the peak bearing capacity of JGJD-2 specimen is nearly double that of the original control specimen, while the improvement of JGJD-1 specimen is relatively limited. After reaching the peak load, the curve of the original specimen JD-1 shows a steep drop, and the bearing capacity decays rapidly. The curves of both types of reinforced specimens are more gradual in the drop section after the peak, and can still maintain a high load level under large displacement loading, showing the best plastic deformation capacity and the ability to maintain bearing capacity in the later stage. Overall, both reinforcement schemes can effectively improve the bearing capacity and ductility of the components. Among them, the JGJD-2 specimen with L-shaped plate in this embodiment has the best comprehensive performance and can achieve a significant optimization of the joint seismic performance.

[0054] The experimentally measured nodal strength and ductility coefficients are shown in Tables 1 and 2: Table 1 shows the node strength.

[0055] Table 2 shows the node ductility coefficients.

[0056] As shown in Tables 1 and 2, the ductility coefficient of the original specimen JD-1 was 3.57, the lowest among all specimens, indicating that the unreinforced joint had limited deformation capacity and insufficient ductility after yielding. Both reinforcement schemes significantly improved the ductility of the specimens. The ductility coefficient of the JGJD-1 specimen increased to 4.49, an increase of about 20.5% compared to the original specimen, indicating that the reinforcement with steel reinforcement of the foundation had a certain effect on improving the ductility of the joint. The ductility coefficient of the JGJD-2 specimen reached 4.88, an increase of 26.8% compared to the original specimen and about 8% compared to JGJD-1. This shows that the L-shaped plate with a leg length of 180mm effectively constrained the plastic hinge zone at the beam end, delayed crack development, and enabled the joint to still have excellent plastic deformation capacity after yielding. Both the bearing capacity and ductility were improved, resulting in the best seismic performance.

[0057] I. Excellent effect of plastic hinge relocation and seismic performance meeting standards. This invention, through the structural design of L-shaped steel plates with triangular ribs, can effectively transfer the plastic hinge at the beam end from the beam root position, which is prone to brittle failure, to a predetermined area at the beam end. This conforms to the seismic design principle of strong nodes and weak members, meets current seismic codes and standards, and effectively compensates for the seismic performance defects of staggered nodes in existing buildings.

[0058] Second, the degree of construction interference is low and the renovation efficiency is high. All steel components of this invention are prefabricated in the factory. On-site construction only requires welding and grouting. The overall construction cycle is short, which can minimize the impact of reinforcement construction on the lives of residents and the normal operation of businesses in existing buildings, and meet the construction needs of efficient and low-disruption renovation of existing buildings.

[0059] Third, the structure exhibits excellent structural synergy and significantly improved load-bearing capacity. The reinforced structure is integrated into a unified reinforced whole through a combination design of external angle steel and gusseted plate system, L-shaped steel plates with triangular ribs 3, and beam steel plates 5. Relying on the bonding and filling properties of the grouting material, the external steel structure is closely integrated with the original building structure, sharing the load effectively and avoiding the problem of local stress concentration in the structure. This significantly improves the overall load-bearing capacity and structural stability of the staggered nodes, and extends the overall service life of the building.

[0060] IV. The structure boasts strong reinforcement reliability and excellent durability. All steel components employ a full-welding connection process, ensuring stable weld strength and high connection reliability. Simultaneously, the grouting material effectively enhances the interfacial bond strength between steel and concrete, as well as the overall structural integrity, preventing issues such as voids and slippage during long-term use. This significantly reduces the frequency and cost of subsequent maintenance, effectively lowering the overall investment throughout the building's lifecycle.

[0061] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A composite column-beam staggered joint reinforcement structure, wherein the composite column-beam staggered joint is formed by a combination of columns and high and low beams, wherein the high and low beams include high beams and low beams; characterized in that, The reinforcement structure includes a steel frame for column outer wrapping (1), a steel frame for beam outer wrapping (2), an L-shaped steel plate with triangular ribs (3), a channel steel plate with triangular ribs (4), and a steel plate for beam (5). The steel frame (1) surrounding the column is fixedly assembled on the outside of the column body; The steel frame (2) of the beam is fixedly assembled on the outside of the high and low beams; The outer steel frame of the beam (2) and the outer steel frame of the column (1) are integrally fixed together; The L-shaped steel plate with triangular ribs (3) is assembled and fixed to the upper side of the high beam and the lower side of the low beam at the root of the staggered node of the composite column and beam, and is fixedly connected to the outer steel frame of the column (1) and the outer steel frame of the beam (2) respectively. The triangular ribbed steel plate (4) is assembled and fixed to the area below the high beam and above the low beam at the root of the staggered node of the composite column and beam, and is fixedly connected to the outer steel frame of the column (1) and the outer steel frame of the beam (2) respectively. The beam steel plate (5) is fitted and assembled on the outer surface of the high and low beams, and is fixedly connected to the L-shaped steel plate (3) with triangular ribs, the grooved steel plate (4) with triangular ribs, and the outer steel frame (2) of the beam respectively; the beam steel plate (5) serves as an extension of the L-shaped steel plate (3) with triangular ribs and the grooved steel plate (4) with triangular ribs along the horizontal direction of the beam, and is used to guide the plastic hinge at the beam end to transfer from the beam root to the predetermined area outside the beam.

2. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, The steel frame (1) surrounding the column includes column angle steel (6) and column gusset plate (7). The column angle steel (6) is vertically arranged along the four corners of the column; the column gusset plate (7) is horizontally fixedly connected between two adjacent column angle steels (6).

3. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, The outer steel frame (2) of the beam includes beam angle steel (8), first beam gusset plate (9), second beam gusset plate (10) and third beam gusset plate (11); The angle steel (8) is fitted and wrapped around the four corners of the high and low beams, and the angle steel (8) is fitted along the root of the high and low beams in the length direction; The first beam lacing plate (9), the second beam lacing plate (10), and the third beam lacing plate (11) are fixedly connected to the inner side of the beam angle steel (8) in a two-way layout. Multiple sets of beam lacing plates and beam angle steel (8) work together to form an overall rigid skeleton structure.

4. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, The L-shaped steel plate (3) with triangular ribs includes an L-shaped steel plate (12) and triangular ribs (13). The L-shaped steel plate (12) is fixed to the area above the high beam and below the low beam at the root of the staggered node of the composite column-beam; The triangular ribs (13) are fixedly arranged on the inner side of the L-shaped steel plate (12) and are evenly arranged along the length of the L-shaped steel plate (12); The vertical limbs of the L-shaped steel plate (12) are attached and fixed to the outer steel frame (1) of the column, and the horizontal limbs of the L-shaped steel plate (12) are fixedly connected to the outer steel frame (2) of the beam.

5. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, The channel steel plate (4) with triangular ribs includes a channel steel plate (14), triangular ribs (13) and a flat steel plate (15). The channel steel plate (14) is fixed to the area below the high beam and above the low beam of the staggered node; The inner sides of the upper and lower sides of the channel steel plate (14) are fixedly fitted with triangular ribs (13). The flat steel plate (15) is fixedly connected with the channel steel plate (14) and the triangular rib (13) to form a closed integral force transmission component; The channel-shaped steel plate (14) is fixedly attached to the end of the staggered high and low beam and is fixedly connected to the column outer steel frame (1) and the beam outer steel frame (2) respectively.

6. The composite column-beam staggered joint reinforcement structure according to claim 5, characterized in that, The arrangement spacing of the triangular ribs (13) matches the width of the high and low beams; wherein, the triangular ribs (13) on the inner side of the channel steel plate (14) are arranged in close contact with the inner edge of the channel steel plate (14), and the remaining triangular ribs (13) are evenly arranged according to the beam width spacing.

7. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, The horizontal leg length of the L-shaped steel plate (3) with triangular ribs satisfies the following relationship: In the formula, The horizontal leg length of the L-shaped steel plate with triangular ribs; l p1 , l p2 These are the calculated values ​​for the lengths of the two sets of plastic hinges, respectively. h 0 represents the effective height of the beam section; z This is the distance from the support at the beam end to the column. for l p1 , l p2 The maximum value in.

8. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, The tension plate extension length of the beam steel plate (5) satisfies the following relationship: In the formula, The tensile extension length of the steel plate of the beam; This refers to the total thickness of the steel plate being bonded. Design value for the tensile strength of reinforced steel plates; This is the design value for the bond strength between the steel plate and the concrete; Reserved length for construction.

9. The composite column-beam staggered joint reinforcement structure according to claim 1, characterized in that, Grouting material is filled between the column outer steel frame (1) and the column body, and between the beam outer steel frame (2) and the high and low beam bodies.

10. A construction method for a composite column-beam staggered joint reinforcement structure, used to assemble the composite column-beam staggered joint reinforcement structure according to any one of claims 1-9, characterized in that, include: The column angle steel (6) is attached to the four corners of the column and fixed, and the column lacing plate (7) is welded to form the column outer steel frame (1). Wrap the high and low beams with the angle steel (8), weld the beam gusset plates to form the outer steel frame (2) of the beam, and weld the root of the outer steel frame (2) of the beam and the outer steel frame (1) of the column to form the whole reinforcement cage; The triangular ribs (13) are welded onto the L-shaped steel plate (12) and the channel steel plate (14) respectively to obtain the L-shaped steel plate (3) with triangular ribs and the channel steel plate (4) with triangular ribs; the L-shaped steel plate (3) with triangular ribs and the channel steel plate (4) with triangular ribs are positioned at the staggered node of the composite column and beam, and are welded and fixed to the column angle steel (6) and the beam angle steel (8) respectively; On the high and low beams, beam steel plates (5) are welded along the horizontal direction of the beams. The L-shaped steel plate (3) with triangular ribs and the grooved steel plate (4) with triangular ribs are welded to the corresponding beam steel plates (5) respectively, so that the beam steel plates (5) can be used as extensions of the L-shaped steel plate (3) with triangular ribs and the grooved steel plate (4) with triangular ribs respectively, and the overall outer steel system assembly is completed. Grouting material is injected between the outer steel frame (1) of the column and the column body, and between the outer steel frame (2) of the beam and the high and low beam bodies respectively. After the grouting material is cured to reach the design strength, the reinforcement construction of the staggered joint of the composite column and beam is completed.

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