Self-resetting energy dissipation beam column joint with staged rigidity and mounting method

Abstract

The invention discloses a self-resetting energy dissipation beam column joint with staged rigidity and a mounting method. The beam column joint comprises a beam connecting assembly, a column connecting assembly, a self-resetting system and an energy dissipation system. The self-resetting system adopts a variable-stiffness spring group consisting of a disc spring, a conical spring and a cylindrical spring, and through the design of free height difference between the springs, initial stiffness and restoring force are provided during small earthquakes, and staged response of enhanced stiffness and gradually-hardened restoring force is provided during large earthquakes; according to the energy dissipation system, a lever amplification mechanism is formed by a chain rod, a dowel bar and an energy dissipation plate, the energy dissipation plate is mainly subjected to tensile yield during small earthquakes, and the energy dissipation plate enters a stretch-bending composite yield state through lever effect triggering during large earthquakes. According to the invention, the frame structure can keep excellent resetting capability and energy dissipation capability under the action of earthquakes with different intensities, and damage is concentrated on independent and replaceable energy dissipation elements, so that rapid functional recovery of a main body structure after an earthquake is realized.

Description

Technical Field

[0001] This invention relates to the field of seismic reinforcement technology for building structures, and in particular to a self-resetting energy-dissipating beam-column joint with phased stiffness and its installation method. Background Technology

[0002] As the concept of seismic design in modern buildings evolves from "life safety" to "post-earthquake functional recovery," higher demands are placed on the damage control capabilities of reinforced concrete frame structures. Beam-column joints, as critical force transmission points, directly determine the degree of damage to the overall structure and the cost of post-earthquake repair due to their seismic performance. Traditional cast-in-place joints or ordinary reinforcement methods are prone to irreversible concrete crushing, steel yielding, and even bond slippage under strong earthquakes, resulting in large residual deformations and difficult repairs. Although self-resetting systems using high-strength prestressed tendons can effectively control residual deformation, their construction is complex, anchorage requirements are high, long-term prestress loss is significant, and most solutions do not systematically consider the graded triggering and replaceability of energy-dissipating components under different intensities of ground motion, limiting their economic efficiency and applicability, and particularly hindering the rapid and efficient seismic reinforcement of existing frames.

[0003] Existing reinforcement techniques, such as external steel cladding, steel bonding, or carbon fiber reinforcement, while improving joint strength and stiffness, often exacerbate the structure's seismic response, potentially transferring damage to adjacent weak points. Furthermore, they lack self-resetting capabilities, making post-earthquake structural functional interruption difficult to avoid. Some reinforcement schemes employing buckling-restrained braces or dampers improve energy dissipation capacity, but their connection points to the main structure may fail before the devices themselves. Due to the limited rotation angle of beams and columns, the energy dissipation level provided by the tensile deformation of energy-dissipating plates at the upper and lower flanges of beams is limited, often causing irreparable damage to other parts of the joint under strong earthquakes. Summary of the Invention

[0004] Purpose of the invention: The present invention aims to provide a self-resetting energy-dissipating beam-column joint with phased stiffness and an installation method, so that the frame structure can maintain excellent reset and energy dissipation capabilities under earthquakes of different intensities, and concentrate damage on independent, replaceable energy-dissipating components, thereby achieving rapid functional recovery of the main structure after an earthquake.

[0005] Technical solution: The present invention provides a self-resetting energy-dissipating beam-column joint with phased stiffness, comprising a beam connection assembly and a column connection assembly respectively connected to a frame beam and a frame column, as well as a self-resetting system and an energy-dissipating system provided on the beam connection assembly and the column connection assembly. The self-resetting system includes at least one set of variable stiffness reset components; the variable stiffness reset components include a second spring group with a second stiffness and a first spring group with a first stiffness symmetrically arranged on both sides of the second spring group. Through the free height difference design, in the initial preload state, only the first spring group works to provide the initial stiffness in the first stage; when the relative rotation of the nodes reaches a first threshold, the second spring group begins to be compressed and works together to provide the enhanced stiffness and self-resetting force in the second stage. The energy-consuming system includes an energy-consuming plate, a force transmission rod, and two chain rods. The two ends of the energy-consuming plate are respectively mounted on the beam connection assembly and the column connection assembly. One end of each of the two chain rods is rotatably connected to the other, and the other end is rotatably connected to the column connection assembly and the beam connection assembly, respectively. One end of the force transmission rod is hinged to the one end of the two chain rods that are rotatably connected to the other, and the other end is perpendicularly pressed against the energy-consuming plate, forming a lever amplification mechanism. When the relative rotation of the nodes reaches the second threshold, it amplifies the displacement of the energy-consuming plate, causing the energy-consuming plate to enter a tensile-bending composite yield state.

[0006] Preferably, the beam connection assembly includes a top plate, a bottom plate, and a sealing plate; the top plate is connected to the frame beam, the bottom plate is opposite to the top plate, and is fixedly connected to the top plate through the sealing plate; a first connecting plate is inclinedly provided on the sealing plate for installing an energy-dissipating plate.

[0007] Preferably, a first stiffening plate is provided between the first connecting plate and the sealing plate.

[0008] Preferably, the column connection assembly includes a column connection plate connected to the frame column, and a second connection plate is inclinedly arranged on the column connection plate. The inclination angle of the second connection plate is on the same inclined straight line as the first connection plate of the beam connection assembly, and the energy dissipation plate in the energy dissipation system is installed together.

[0009] Preferably, a second stiffening plate is provided between the second connecting plate and the column connecting plate.

[0010] Preferably, the first spring assembly includes a disc spring sleeved on the guide rod, and the guide rod includes at least two rods. One end of the guide rod is rotatably connected to the column connecting plate of the column connecting assembly, and the other end passes through the bottom plate of the beam connecting assembly and is sleeved with a disc spring, and then a pad is installed for pre-tightening. The second spring assembly includes a conical spring and a cylindrical spring sleeved on a lead screw. The lead screw is located between two guide rods. One end of the lead screw is screwed into the base plate of the beam connecting assembly, and the other end is sleeved with a conical spring and a cylindrical spring before being pre-tightened with a pad.

[0011] Preferably, the free height of the disc spring is greater than the free height of the conical spring and the cylindrical spring.

[0012] Preferably, the conical spring is sleeved on the outside of the cylindrical spring.

[0013] Preferably, the energy-dissipating plate is disposed at both ends on the first connecting plate of the beam connecting assembly and the second connecting plate of the column connecting assembly.

[0014] The installation method of a self-resetting energy-dissipating beam-column joint with phased stiffness according to the present invention includes the following steps: (1) Prefabrication and installation of beam connection assemblies and column connection assemblies; (2) Install a self-reset system, including: (2.1) Hinge one end of the guide rod fitted with the first spring assembly to the column connection assembly; (2.2) After the guide rod passes through the beam connecting assembly, it is fitted into the first spring assembly; (2.3) Screw one end of the lead screw with the second spring assembly into the beam connection assembly, and fit the other end into the second spring assembly; (2.4) Install pads on the outside of the first and second spring groups, and finally tighten the nuts to the designed preload to ensure that the spring groups reach the preset initial compression state; (3) Install energy-consuming systems; including: (3.1) Hinge one end of each of the two chain rods to the beam connection assembly and the column connection assembly respectively; (3.2) Hinge one end of the force transmission rod to the other end of the two chain rods; (3.3) Place the energy dissipation plate on the other end of the force transmission rod and press it tightly. Then fix both ends of the energy dissipation plate to the first connecting plate of the beam connection assembly and the second connecting plate of the column connection assembly, respectively.

[0015] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: 1. The self-resetting system adopts a variable stiffness spring group composed of springs of different stiffnesses (disc springs, conical springs, and cylindrical springs). Through the design of the free height difference between the springs, it achieves a phased response that provides initial stiffness and restoring force during minor earthquakes and enhanced stiffness and gradually hardening restoring force during major earthquakes. Moreover, compared with the traditional self-resetting system that relies on high-strength prestressed tendons, the spring drive system of the present invention avoids complex anchoring and long-term prestress loss problems, making it more reliable and economical. 2. The energy dissipation system forms a lever amplification mechanism through chain rods, force transmission rods, and replaceable energy dissipation plates. During minor earthquakes, the energy dissipation plate mainly undergoes tensile yielding. During major earthquakes, the lever effect triggers, causing the energy dissipation plate to enter a tensile-bending composite yielding state, significantly improving the energy dissipation capacity. 3. By integrating the variable stiffness self-resetting system with the energy dissipation system with lever amplification effect, and through threshold design, the two form a phased collaborative working system under nodal displacement response, providing sufficient stiffness and initial stiffness under common and design earthquakes. 4. Excellent post-earthquake recoverability and economy: The core of the energy dissipation system—the replaceable energy dissipation plate—is an independent component and the only pre-designed centralized energy dissipation and damage-handling component in the system. If it is damaged after an earthquake, it can be quickly inspected, disassembled, and replaced with a new plate, while the main concrete of the beams and columns and the self-resetting system remain intact without repair. This greatly shortens the maintenance time, significantly reduces the repair cost and functional interruption loss, and achieves the tough goal of rapid functional recovery after an earthquake. 5. Convenient construction and wide application range: All components of the node can be prefabricated in the factory. Only bolt connections and pin hinges are required on site. The degree of assembly is high, the construction speed is fast, and the disturbance to the existing structure is minimal. This technical solution is not only applicable to the performance-based design of new structures, but also provides an efficient, reliable and economical solution for seismic strengthening and toughness enhancement of existing reinforced concrete frame structures. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a structural schematic diagram of the beam connection assembly of the present invention; wherein, (a) is an overall structural diagram of the beam connection assembly, and (b) is an exploded view of the beam connection assembly; Figure 3 This is a schematic diagram of the structure of the column connection assembly in this invention; Figure 4 This is a schematic diagram of the self-resetting system and the energy-consuming system in this invention; Figure 5This is a schematic diagram of the structure of the guide rod, chain rod, force transmission rod, and energy dissipation plate in this invention; Figure 6 This is a schematic diagram of the phased stiffness principle of the self-resetting system in this invention; wherein, (a) is a schematic diagram of the initial state, (b) is a schematic diagram of the first compression state P1, and (c) is a schematic diagram of the second compression state P2. Figure 7 This is a schematic diagram illustrating the principle of amplifying the energy consumption capacity of the energy-consuming system in this invention.

[0017] In the diagram: 1. Beam connection assembly; 1-1. Top plate; 1-2. Bottom plate; 1-2a. Internal threaded hole; 1-2b. Through hole; 1-2c. First ear plate; 1-3. Side plate; 1-4. Sealing plate; 1-4a. First connecting plate; 1-4b. First stiffening plate; 2. Column connection assembly; 2-1. Column connecting plate; 2-2a. Second ear plate; 2-2b. Third ear plate; 2-3. Second connecting plate; 2-4. Second stiffening plate; 3. Self-resetting system 3-1, Guide rod; 3-1a, First end plate; 3-1b, First connecting rod; 3-2, Disc spring; 3-3, Conical spring; 3-4, Cylindrical spring; 3-5, Lead screw; 3-6, Pad plate; 4, Energy dissipation system; 4-1, Chain rod; 4-1a, Second end plate; 4-1b, Second connecting rod; 4-1c, First hinge joint; 4-2, Force transmission rod; 4-2a, Third connecting rod; 4-2b, Second hinge joint; 4-3, Energy dissipation plate. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0019] like Figure 1-7 As shown, the self-resetting energy-dissipating beam-column joint with phased stiffness according to the present invention includes a beam connection component 1, a column connection component 2, a self-resetting system 3, and an energy-dissipating system 4.

[0020] The beam connection assembly 1, as a key force-transmitting component connecting to the frame beam, includes a top plate 1-1, a bottom plate 1-2, side plates 1-3, and a sealing plate 1-4 connected as a rigid whole. Figure 2 As shown. The top plate 1-1 is connected to the frame beam. Preferably, the top plate 1-1 is fixed to the lower flange of the frame beam by high-strength bolts. The bottom plate 1-2 is opposite to the top plate 1-1 and is fixedly connected to the top plate 1-1 by the side plates 1-3 on both sides and the front sealing plate 1-4. Preferably, the top plate 1-1, bottom plate 1-2, side plates 1-3 and sealing plate 1-4 are welded together. A first connecting plate 1-4a is inclinedly provided on the sealing plate 1-4, and a first stiffening plate 1-4b is provided between the first connecting plate 1-4a and the sealing plate 1-4 to enhance the stability of the first connecting plate 1-4a.

[0021] The base plate 1-2 is the main mounting base of the self-resetting system 3. The first connecting plate 1-4a provides a mounting surface for the energy-consuming plate 4-3 of the energy-consuming system 4.

[0022] The column connection assembly 2, serving as a component connecting to the frame column, includes a column connection plate 2-1. The column connection plate 2-1 is connected to the frame column, preferably fixed to the frame column by high-strength bolts. A second connection plate 2-3 is obliquely arranged on the column connection plate 2-1, and a second stiffening plate 2-4 is provided between the second connection plate 2-3 and the column connection plate 2-1 to enhance the stability of the second connection plate 2-3. Figure 3 As shown. The tilt angle of the second connecting plate 2-3 corresponds to that of the first connecting plate 1-4a, and together they clamp and fix the energy dissipation plate 4-3 in the energy dissipation system 4.

[0023] The self-resetting system 3, as the core providing restoring force and variable stiffness performance, includes at least one set of variable stiffness reset components. Each variable stiffness reset component includes a second spring group with a second stiffness and a first spring group symmetrically arranged on both sides of the second spring group with a first stiffness. Through the free height difference design, in the initial pre-tightened state, only the first spring group works, providing initial stiffness in the first stage. When the relative rotation of the nodes reaches a first threshold, the second spring group begins to be compressed and works together, providing enhanced stiffness and self-resetting force in the second stage. Preferably, the variable stiffness reset component includes at least two guide rods 3-1. One end of each guide rod 3-1 is rotatably connected to the column connecting plate 2-1 of the column connecting assembly 2, and the other end passes through a through hole 1-2b provided on the bottom plate 1-2 of the beam connecting assembly 1, then a disc spring 3-2 is fitted onto it, and then a pad 3-6 is installed before pre-tightening with a nut. The variable stiffness reset assembly also includes at least one lead screw 3-5, which is located between the two guide rods 3-1. One end of the lead screw 3-5 is screwed into the internal threaded hole 1-2a provided on the base plate 1-2 of the beam connecting assembly 1, and the other end is fitted with a conical spring 3-3 and a cylindrical spring 3-4. Then, a pad 3-6 is installed and fixed with a nut. Figure 4 and 6 As shown. The conical spring 3-3 and the cylindrical spring 3-4 are coaxially arranged, with the conical spring 3-3 sleeved on the outside of the cylindrical spring 3-4. The free height of the disc spring 3-2. h 1 is greater than the free height of the conical spring 3-3 and the cylindrical spring 3-4, and the pad 3-6 and nut are used to tighten and adjust the preload of the entire spring assembly, together forming a variable stiffness spring assembly, such as... Figure 6 (a) shows the initial state. Preferably, the free height of the conical spring 3-3 and the cylindrical spring 3-4 is the same, which is h2.

[0024] The energy dissipation system 4 includes an energy dissipation plate 4-3, a force transmission rod 4-2, and two chain rods 4-1. The energy dissipation plate 4-3 is a low-yield-point steel plate with a weakened central region, with its two ends respectively located on the first connecting plate 1-4a of the beam connection assembly 1 and the second connecting plate 2-3 of the column connection assembly 2. It acts as a pre-set "fuse," serving as a primary centralized energy dissipation and replaceable component during earthquakes. The two chain rods 4-1 are rotatably connected at one end to each other, and their other ends are rotatably connected to the column connecting plate 2-1 of the column connection assembly 2 and the base plate 1-2 of the beam connection assembly 1, respectively. One end of the force transmission rod 4-2 is hinged to the rotatably connected end of the two chain rods, and the other end is connected to the energy dissipation plate 4-3, preferably vertically; for example... Figure 4 As shown. The energy-consuming system 4 constitutes a lever amplification mechanism, which amplifies the displacement of the energy-consuming plate when the relative rotation of the nodes reaches the second threshold, causing the energy-consuming plate to enter a tensile-bending composite yield state.

[0025] In this embodiment, as Figure 5 As shown, preferably, the guide rod 3-1 includes a first end plate 3-1a and a first connecting rod 3-1b connected to each other. The first end plate 3-1a is hinged to a second ear plate 2-2a provided on the column connecting plate 2-1 by a pin. The chain rod 4-1 includes a second end plate 4-1a, a second connecting rod 4-1b and a first hinge joint 4-1c connected in sequence. The second end plates 4-1a of the two chain rods 4-1 are respectively hinged to the first ear plate 1-2c provided on the bottom plate 1-2 of the beam connecting assembly 1 and the third ear plate 2-2b provided on the column connecting plate by pins. The first hinge joint 4-1c of the two chain rods 4-1 is hinged to the second hinge joint 4-2b of the force transmission rod 4-2 by a pin. The energy-consuming plate 4-3 is a centrally weakened plate made of low yield point steel. The width of its central weakened area is 40% to 60% of the total width of the plate. A central threaded hole is provided in the center of the energy-consuming plate 4-3. The third connecting rod 4-2a of the force transmission rod 4-2 is a variable diameter screw rod. Its end diameter reduction section is connected to the central threaded hole of the energy-consuming plate 4-3 to realize the perpendicular pressing of the force transmission rod 4-2 and the surface of the energy-consuming plate 4-3.

[0026] The energy dissipation system of this invention is designed to form a lever amplification mechanism: the two chain rods and the force transmission rod utilize the geometric lever amplification mechanism to amplify the relative rotational displacement of the nodes and apply it to the energy dissipation plate, thereby amplifying the energy dissipation capacity. When the node rotation angle is less than the second threshold, the energy dissipation plate mainly dissipates energy through tensile deformation; when the node rotation angle reaches or exceeds the second threshold, the lever amplification mechanism forces the force transmission rod to apply a significant lateral compressive force to the energy dissipation plate, causing it to enter a tensile-bending combined yield state, and the energy dissipation capacity is greatly amplified.

[0027] The installation method of a self-resetting energy-dissipating beam-column joint with phased stiffness according to the present invention includes the following steps: (1) Prefabrication and installation of beam connection components and column connection components.

[0028] In the factory, the components of beam connection assembly 1 and column connection assembly 2 are welded together as a whole, and then fixed to the lower end of the frame beam and the top of the frame column on site with high-strength bolts.

[0029] (2) Install the self-reset system 3, specifically including: (2.1) The first end plate 3-1a of the prefabricated guide rod 3-1 is hinged to the second ear plate 2-2a of the column connecting plate with a pin.

[0030] (2.2) Pass the first connecting rod 3-1b of the guide rod 3-1 through the through hole 1-2b of the bottom plate 1-2 of the beam connecting assembly, and put the disc spring 3-2 on the first connecting rod 3-1b.

[0031] (2.3) Screw the lead screw 3-5 into the internal threaded hole 1-2a of the bottom plate 1-2 of the beam connecting assembly, and then put the cylindrical spring 3-4 and the conical spring 3-3 on the lead screw 3-5 in sequence, with the conical spring 3-3 on the outside of the cylindrical spring 3-4.

[0032] (2.4) Install pads 3-6, and finally tighten the nuts to the designed preload to ensure that the spring assembly reaches the preset initial compression state, such as... Figure 6 As shown in (a).

[0033] (3) Install energy-consuming system 4, specifically including: (3.1) The second end plate 4-1a of the chain rod 4-1 is hinged to the first ear plate 1-2c on the bottom plate 1-2 of the beam connection assembly and the third ear plate 2-2b on the column connection plate with pins.

[0034] (3.2) Hing one end of the force transmission rod 4-2 to the first hinge joint 4-1c of the two chain rods 4-1 with a pin.

[0035] (3.3) Place the energy dissipation plate 4-3 on the other end of the force transmission rod 4-2 and press it tightly. Then, use high-strength bolts to fix both ends of it to the first connecting plate 1-4a of the beam connection assembly and the second connecting plate 2-3 of the column connection plate, respectively.

[0036] The working principle of this invention is as follows: Phase 1: Under the action of minor / frequent earthquakes The beam-column joint rotation angle is small. The self-resetting system 3, due to the preload and the free height difference (Δ), h = h 1 – h 2) At this point, only disc spring 3-2 is compressed, providing initial stiffness. k 1. With most of the restoring force, the conical spring 3-3 and the cylindrical spring 3-4 are in a free state, such as... Figure 6(b) is the first compression state P1. During this stage, the nodes exhibit high elasticity and minimal residual deformation.

[0037] Because the node rotation angle is small, the angle change of the link 4-1 in the energy dissipation system 4 is minimal, and the pressure of the force transmission link 4-2 on the energy dissipation plate 4-3 is also small. F 1 is very small and its direction is almost perpendicular, such as Figure 7 As shown in (a), the energy dissipation plate 4-3 is mainly under tension, providing stable initial energy dissipation.

[0038] The beam-column joints at this stage exhibit high elastic stiffness. k 1. It works in conjunction with the foundation tensile energy dissipation to ensure the normal functioning of the structure.

[0039] Phase Two: Under Moderate / Designated Earthquake Action When the rotation angle of the beam-column joint reaches the first threshold θ 1. The relative displacement of the beam and column causes a change in the relative position of the base plate 1-2 and the pad 3-6, continuing to compress the variable stiffness reset component in the self-resetting system 3. At this time, the conical spring 3-3 and the cylindrical spring 3-4 begin to be compressed and jointly participate in the load-bearing, such as... Figure 6 (c) shows the second compression state P2. The system stiffness changes from... k 1 Significantly improved to k 2 ( k 2> k 1) The gradually stiffening characteristic of the conical spring begins to emerge, providing a continuously increasing restoring force and laying the foundation for controlling damage to the main structure. Therefore, the first threshold θ1 is also the stiffness transition threshold.

[0040] When the beam-column joint rotation angle reaches the second threshold θ 2. In the energy dissipation system 4, the angle between the two chain rods 4-1 increases, causing the force transmission rod 4-2 to exert a significant compressive force on the energy dissipation plate 4-3. F 2, such as Figure 7 As shown in (b), the energy-dissipating plate 4-3 enters a combined tensile-bending yield state, and its energy dissipation efficiency is initially amplified compared to pure tension. Therefore, the second threshold... θ 2 is also the threshold for triggering energy consumption amplification.

[0041] This stage is a critical period for synergistic triggering. The stiffness and restoring force of the self-resetting system 3 are enhanced simultaneously, effectively limiting deformation; the energy dissipation system 4 amplifies its energy dissipation capacity for the first time, efficiently dissipating energy. The two work together to achieve a comprehensive effect of "enhanced stiffness, amplified energy dissipation, and damage prevention and control".

[0042] Phase Three: Under the influence of major / rare earthquakes Under large deformation, the spring assembly of the self-resetting system 3 is further compressed, and the gradually stiffening characteristics of the conical spring 3-3 dominate. The restoring force increases nonlinearly and rapidly, providing a large restoring force to strongly limit the maximum deformation and ensure complete post-earthquake reset, keeping the residual deformation at an extremely low level.

[0043] The large rotation angle of the two chain rods in the energy dissipation system 4 further amplifies the leverage effect on the force transmission rod 4-2, increasing the compressive force of the force transmission rod 4-2 on the energy dissipation plate 4-3 to [amount missing]. F 3, such as Figure 7 As shown in (c), the energy dissipation plate 4-3 is forced to undergo large deflection bending deformation, the plastic hinge is fully developed, and the energy dissipation capacity is fully amplified to the design maximum value.

[0044] This phase aims for ultimate safety. The self-resetting system 3 provides strong resilience to prevent collapse; the energy dissipation system 4 maximizes its potential to protect the main structure. Together, they ensure "no collapse even in a major earthquake" and rapid functional recovery afterward.

[0045] This invention designs a stiffness transition threshold. θ 1 and energy consumption amplification trigger threshold θ 2. Mutual matching: The stiffness change stage of the self-resetting system 3 and the energy dissipation amplification triggering stage of the energy dissipation system 4 are coordinated and matched according to the nodal displacement response, forming a phased collaborative working system. This allows the nodes to primarily dissipate energy through initial stiffness and tension under small to medium earthquakes; under moderate to strong earthquakes and above, the two systems enter a highly efficient working state simultaneously or successively. That is, the self-resetting system provides enhanced restoring force to control deformation, while the energy dissipation system achieves massive energy dissipation through amplification mechanism. Thus, the optimal combination of "stiffness-energy dissipation-restoring force" can be achieved under different levels of ground motion, ensuring that the node performance achieves overall and synchronous performance upgrades at moderate to strong earthquake levels.

[0046] Among them, the stiffness conversion threshold of the self-resetting system 3 θ 1 (i.e., the angle at which the conical spring 3-3 and the cylindrical spring 3-4 begin to work) and the energy dissipation amplification trigger threshold of the energy dissipation system 4. θ 2 (i.e., the angle at which the force transmission rod 4-2 begins to bend the energy dissipation plate 4-3) should be designed to be the same or very close, so that the energy dissipation amplification triggering stage of the energy dissipation system 4 and the second stiffness enhancement stage of the self-resetting system 3 occur synchronously or successively in terms of node displacement, for example, both are set to the same inter-story displacement angle. The free height difference Δh between the disc spring 3-2, the conical spring 3-3, and the cylindrical spring 3-4, as well as the initial preload of the variable stiffness spring group, jointly determine the stiffness conversion threshold. θThe magnitude of 1; by adjusting Δh and the initial preload of the variable stiffness spring assembly, the node displacement point where the stiffness is significantly enhanced can be preset. The length of the chain rod 4-1, its initial angle with the horizontal direction, the initial position of the force transmission rod 4-2, and the initial installation position of the energy dissipation plate 4-3 together determine the trigger sensitivity and amplification factor of the energy dissipation amplification mechanism; by adjusting these geometric parameters, the node displacement point where the force transmission rod exerts a significant lateral compressive force on the energy dissipation plate can be preset.

[0047] Although the self-resetting system 3 and the energy dissipation system 4 work together, the two systems are relatively independent in terms of both physics and function. The self-resetting system 3 provides restoring force throughout the earthquake and requires no maintenance afterward; the energy dissipation system 4 focuses on energy dissipation and is the only replaceable component. This "cooperative operation, independent maintenance" design is the foundation for achieving efficient post-earthquake recovery capabilities.

[0048] This invention achieves the goal of concentrating damage on replaceable energy-dissipating panels, enabling rapid replacement after an earthquake, minimizing residual deformation of the main structure, and facilitating quick functional recovery. It is particularly suitable for efficient and economical seismic reinforcement and toughness enhancement of existing reinforced concrete frames.

[0049] In a preferred embodiment, the following design parameters are used to specifically illustrate the implementation and technical effects of the present invention. The disc spring in the self-resetting system 3 is made of 60Si2Mn steel, with a free height... h 1=50mm, the free height of both the conical spring and the cylindrical spring is 50mm. h 2=35mm, height difference Δh=15mm. The working height of the spring assembly after preload is 60mm. Design stiffness conversion threshold. θ 1 = 0.015 rad. When the beam-column rotation angle... θ At >0.015 rad, the overall system stiffness increases by approximately 1.8 times. The energy dissipation plate of energy dissipation system 4 is made of LY225 low-yield-point steel, with dimensions of 800mm × 300mm × 12mm, and a central oval hole with a minimum width of 150mm (a 50% reduction in stiffness). The force transmission rod has a diameter of 30mm. The energy dissipation amplification trigger threshold is designed. θ 2 = 0.015 rad, and θ 1. Matching. The angle between the first and second connecting plates of the fixed energy dissipation plate (the angle with the vertical direction) is 20°, optimizing force transmission and facilitating replacement. Under moderate to severe earthquakes, the beam-column joint rotation angle... θ =0.01~0.03 rad. Due to the lever amplification mechanism, the energy dissipation capacity of energy dissipation system 4 is about 3-5 times higher than that of pure tensile energy dissipation of a plate of the same size. After the earthquake, the self-resetting system 3 drives the nodes to close almost completely, and only the damaged energy dissipation plate needs to be replaced to achieve rapid functional recovery.

Claims

1. A self-resetting energy-dissipating beam-column joint with phased stiffness, characterized in that, It includes a beam connection assembly (1) and a column connection assembly (2) that are respectively connected to the frame beam and the frame column, as well as a self-resetting system (3) and an energy dissipation system (4) installed on the beam connection assembly (1) and the column connection assembly (2); The self-resetting system (3) includes at least one set of variable stiffness reset components; the variable stiffness reset components include a second spring group with a second stiffness and a first spring group with a first stiffness symmetrically arranged on both sides of the second spring group. Through the free height difference design, in the initial pre-tightened state, only the first spring group works to provide the initial stiffness of the first stage; when the relative rotation of the nodes reaches the first threshold, the second spring group begins to be compressed and works together to provide the enhanced stiffness and self-resetting force of the second stage. The energy dissipation system (4) includes an energy dissipation plate (4-3), a force transmission rod (4-2), and two chain rods (4-1). The two ends of the energy dissipation plate (4-3) are respectively mounted on the beam connection assembly (1) and the column connection assembly (2). One end of the two chain rods (4-1) is rotatably connected to each other, and the other end is rotatably connected to the column connection assembly (2) and the beam connection assembly (1), respectively. One end of the force transmission rod (4-2) is pivotally connected to the two chain rods, and the other end is connected to the energy dissipation plate (4-3), forming a lever amplification mechanism. When the relative rotation of the nodes reaches the second threshold, it amplifies the displacement of the energy dissipation plate (4-3), causing the energy dissipation plate to enter the tensile-bending composite yield state.

2. The self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 1, characterized in that, The beam connection assembly (1) includes a top plate (1-1), a bottom plate (1-2), and a sealing plate (1-4); the top plate (1-1) is connected to the frame beam, the bottom plate (1-2) is opposite to the top plate (1-1), and is fixedly connected to the top plate (1-1) by the sealing plate (1-4); a first connecting plate (1-4a) is inclinedly arranged on the sealing plate (1-4).

3. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 2, characterized in that, A first stiffening plate (1-4b) is provided between the first connecting plate (1-4a) and the sealing plate (1-4).

4. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 1, characterized in that, The column connection assembly (2) includes a column connection plate (2-1) connected to the frame column. A second connection plate (2-3) is inclinedly arranged on the column connection plate (2-1). The inclination angle of the second connection plate (2-3) is on the same inclined straight line as the first connection plate (1-4a) of the beam connection assembly (1).

5. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 4, characterized in that, A second stiffening plate (2-4) is provided between the second connecting plate (2-3) and the column connecting plate (2-1).

6. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 1, characterized in that, The first spring assembly includes a disc spring (3-2) sleeved on the guide rod (3-1). The guide rod (3-1) includes at least two rods. One end of the two guide rods is rotatably connected to the column connecting plate (2-1) of the column connecting assembly (2), and the other end passes through the bottom plate (1-2) of the beam connecting assembly (1) and then the disc spring (3-2) is sleeved on it. Then the pad (3-6) is installed and pre-tightened. The second spring assembly includes a conical spring (3-3) and a cylindrical spring (3-4) sleeved on a lead screw (3-5). The lead screw (3-5) is located between two guide rods (3-1). One end of the lead screw (3-5) is screwed into the base plate (1-2) of the beam connecting assembly (1), and the other end is sleeved with the conical spring (3-3) and the cylindrical spring (3-4) before being pre-tightened by installing a pad (3-6).

7. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 6, characterized in that, The free height of the disc spring (3-2) is greater than that of the conical spring (3-3) and the cylindrical spring (3-4).

8. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 6, characterized in that, The conical spring (3-3) is sleeved on the outside of the cylindrical spring (3-4).

9. A self-resetting energy-dissipating beam-column joint with phased stiffness according to claim 1, characterized in that, The energy-consuming plate (4-3) is located at both ends on the first connecting plate (1-4a) of the beam connecting assembly (1) and the second connecting plate (2-3) of the column connecting assembly (2).

10. An installation method for a self-resetting energy-dissipating beam-column joint with phased stiffness according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Prefabrication and installation of beam connection assemblies and column connection assemblies; (2) Install a self-reset system, including: (2.1) Hinge one end of the guide rod fitted with the first spring assembly to the column connection assembly; (2.2) After the guide rod passes through the beam connecting assembly, it is fitted into the first spring assembly; (2.3) Screw one end of the lead screw with the second spring assembly into the beam connection assembly, and fit the other end into the second spring assembly; (2.4) Install pads on the outside of the first and second spring groups, and finally tighten the nuts to the designed preload. (3) Install energy-consuming systems, including: (3.1) Hinge one end of each of the two chain rods to the beam connection assembly and the column connection assembly respectively; (3.2) Hinge one end of the force transmission rod to the other end of the two chain rods; (3.3) Place the energy dissipation plate on the other end of the force transmission rod and press it tightly. Then fix both ends of the energy dissipation plate to the first connecting plate of the beam connection assembly and the second connecting plate of the column connection assembly, respectively.

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