Adaptive anti-lifting device and method based on negative stiffness compensation

Abstract

This invention discloses an adaptive anti-lifting device based on negative stiffness compensation, comprising a friction pendulum seismic isolation bearing and a negative stiffness compensation component. The friction pendulum seismic isolation bearing includes a first base plate, a spherical cap, and a second base plate. The negative stiffness compensation component includes an upper structure connecting plate, a rigid-flexible assembly, negative stiffness compression springs, a ball joint, and cables. The rigid-flexible assembly includes multiple elastic plates and multiple rigid plates. A first groove is formed at the bottom of the rigid-flexible assembly, within which the ball joint and multiple negative stiffness compression springs are arranged. The upper end of the ball joint is fixedly connected to the bottom wall of the first groove, and the lower end of the ball joint extends into a second groove at the top of the first base plate, rotatably connecting the lower end of the ball joint to the first base plate. Multiple cables surround the rigid-flexible assembly. This invention enables dynamic and adaptive adjustment of the lift, effectively preventing overall structural lift without affecting its normal seismic isolation function, thus improving the safety and stability of the structure under extreme loads.

Description

Technical Field

[0001] This invention belongs to the field of bridge seismic isolation technology, and more specifically, relates to an adaptive anti-lift device and method based on negative stiffness compensation. Background Technology

[0002] Large structures such as bridges and high-rise buildings face severe challenges to their safety and stability when subjected to extreme loads such as earthquakes and strong winds.

[0003] Friction pendulum systems (FPS) are widely used seismic isolation devices in bridges, high-rise buildings, and other structures, holding a crucial position. A typical FPS structure consists of an upper bearing plate, a spherical cap, and a second bearing plate. Its primary working principle is to achieve seismic isolation through the sliding friction of the spherical cap and its oscillating motion. Specifically, when horizontal loads such as earthquakes act on the structure, the spherical cap in the FPS slides on the concave surface of the lower bearing plate, while simultaneously utilizing the gravity of the superstructure as a restoring force, allowing the structure to automatically reset after an earthquake. This method effectively prolongs the structure's natural period, reduces the transmission of seismic forces, and thus lowers the structure's response during earthquakes, significantly improving its safety under seismic loads. This is the key reason for its widespread application in numerous large-scale bridge projects.

[0004] However, friction pendulum seismic isolation bearings also have problems in practical engineering applications. One prominent issue is that under extreme loads such as strong earthquakes and strong winds, the spherical cap will slide. Since the spherical cap is in contact with both the upper and lower bearing plates via curved surfaces, the sliding of the spherical cap can cause the upper bearing plate and the superstructure supported by the upper bearing plate to tilt and lift, leading to swaying, instability, and uneven stress on the superstructure.

[0005] Currently, the industry has taken some measures to address the issue of bearing lift in friction pendulum seismic isolation bearings. Traditional passive anti-lift devices are a common solution, such as limit rods and fixed connectors. These devices have relatively fixed structures, limiting bearing lift through mechanical connections. However, these devices have significant limitations. Because load conditions change constantly under different seismic or wind load intensities, passive anti-lift devices cannot dynamically adjust their constraint stiffness according to these changes. This leads to a problem: in some cases, the constraint may be too strong, which can impair the normal seismic isolation function of the friction pendulum seismic isolation bearing, preventing it from achieving its intended isolation effect; while in other cases, the constraint may be insufficient, failing to effectively prevent bearing lift and thus failing to meet the needs of practical engineering projects.

[0006] Besides the limitations mentioned above, most existing anti-lifting technologies lack adaptive adjustment capabilities. In other words, they cannot adjust in real time according to the actual stress and displacement state of the support to adapt to complex and changing load environments. In real-world engineering scenarios, the magnitude and direction of the load can change at any time, requiring anti-lifting measures to make timely adjustments to achieve efficient and precise anti-lifting control. However, most current technologies fail to meet this requirement, which to some extent limits their application effectiveness and scope.

[0007] Furthermore, most existing anti-lift devices are single-function devices, focusing solely on limiting bearing lift without adequately considering their integration with the seismic isolation function of friction pendulum bearings. Consequently, under different operating conditions, structures struggle to simultaneously meet multiple complex requirements, including seismic resistance and post-earthquake recovery. For example, in some cases, besides preventing bearing lift, it's also necessary to ensure the structure can promptly return to its normal function after an earthquake. However, existing anti-lift devices often cannot address these multiple requirements simultaneously, necessitating the addition of other devices or measures to compensate for this deficiency in practical applications, thus increasing engineering complexity and cost.

[0008] To address the uplift problem of friction pendulum seismic isolation bearings, some studies have attempted to solve the problem by improving the structural design of the bearing itself. For example, adding auxiliary sliders and optimizing the surface shape are methods aimed at improving the vertical load-bearing capacity of the bearing to better resist the uplift tendency under extreme loads. Other studies have employed additional damping devices to suppress bearing uplift by consuming energy. However, these methods have also revealed several problems in practical applications. For instance, the structure becomes more complex, which undoubtedly increases manufacturing and installation costs, and may also significantly affect the original seismic isolation performance of the bearing, even potentially having the opposite effect in some cases, failing to achieve the desired results. Summary of the Invention

[0009] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an adaptive anti-lifting device and method based on negative stiffness compensation. By introducing a negative stiffness compensation component for negative stiffness compensation, dynamic and adaptive adjustment of the lifting of the friction pendulum seismic isolation support is achieved. This effectively prevents the overall lifting of the adaptive anti-lifting device without affecting its normal seismic isolation function, thereby improving the safety and stability of the structure under extreme loads.

[0010] To achieve the above objectives, according to one aspect of the present invention, an adaptive anti-lifting device based on negative stiffness compensation is provided, characterized in that it includes a friction pendulum isolation support and a negative stiffness compensation component. The friction pendulum isolation support includes a first seat plate, a spherical cap, and a second seat plate arranged sequentially from top to bottom. The bottom of the first seat plate is provided with a first concave spherical surface, the top of the spherical cap is provided with a first convex spherical surface that contacts the first concave spherical surface, the top of the second seat plate is provided with a second concave spherical surface, and the bottom of the spherical cap is provided with a second convex spherical surface that contacts the second concave spherical surface, wherein:

[0011] The negative stiffness compensation component includes an upper structural connecting plate, a rigid-flexible assembly, a negative stiffness compression spring, a ball joint, and a cable. The rigid-flexible assembly is located between the upper structural connecting plate and the first base plate and is fixedly connected to both the upper structural connecting plate and the first base plate. The rigid-flexible assembly includes multiple plates stacked and fixedly connected together. These plates include multiple elastic plates and multiple rigid plates, with the elastic and rigid plates arranged alternately. A first groove is formed at the bottom of the rigid-flexible assembly, and the bottom wall of the first groove is part of the bottom surface of one of the rigid plates. The ball joint and cable are arranged within the first groove. Multiple negative stiffness compression springs are provided, with the upper end of each spring fixedly connected to the bottom wall of the first groove and the lower end connected to the first base plate. Each spring is in a compressed state. The upper end of the ball joint is fixedly connected to the bottom wall of the first groove, and the lower end extends into the second groove at the top of the first base plate. The lower end of the ball joint is rotatably connected to the first base plate. Multiple cables surround the rigid-flexible assembly. Each cable is in a pre-tensioned state, and the upper and lower ends of each cable are respectively connected to the upper structure connecting plate and the first base plate.

[0012] Preferably, the first base plate includes an adaptive swing block, a central connecting plate, an upper curved sliding connecting plate, and an upper curved sliding layer, which are arranged sequentially from top to bottom and fixedly connected together. The edge of the central connecting plate extends beyond the edge of the adaptive swing block and the edge of the upper curved sliding connecting plate, respectively. The lower end of each cable is fixedly connected to the central connecting plate, and the first concave spherical surface is disposed at the bottom of the upper curved sliding layer.

[0013] Preferably, the adaptive swing block includes a polytetrafluoroethylene block and a stainless steel block arranged from top to bottom and fixedly connected together, and the second groove is disposed on the polytetrafluoroethylene block.

[0014] Preferably, the second base plate includes a lower curved sliding layer, a lower curved sliding connecting plate, and a lower curved sliding limiting seat arranged sequentially from top to bottom and fixedly connected together. The second concave spherical surface is disposed on the top of the lower curved sliding layer, and the edge of the lower curved sliding limiting seat is provided with an annular flange for limiting the sliding stroke of the spherical cap.

[0015] Preferably, the first groove is located in the middle of the rigid-flexible assembly, and the negative stiffness compression spring surrounds the ball joint.

[0016] Preferably, the lower end of the ball joint is rotatably connected to the first base plate through contact with a spherical surface, an ellipsoidal surface, or a figure-eight shaped curved surface.

[0017] Preferably, the first base plate is provided with a plurality of first ear plates, and the second base plate is provided with a second ear plate at a position corresponding to each of the first ear plates.

[0018] Preferably, the rigid plate is made of high-strength alloy steel, the elastic plate is made of rubber, and any adjacent rigid plates and elastic plates are bonded together with adhesive and then fixed together by riveting.

[0019] Preferably, the top and bottom of the rigid-flexible assembly are both made of elastic plates.

[0020] According to another aspect of the present invention, a method for preventing lifting based on an adaptive anti-lifting device with negative stiffness compensation is also provided, characterized by comprising the following steps:

[0021] 1) The upper structure connecting plate is fixedly installed on the upper structure of the building, and the second plate is fixedly installed on the lower structure of the building, wherein the building is a highway bridge, railway bridge or high-rise building;

[0022] 2) When the lower structure of the building is subjected to a horizontal load impact, the second convex spherical surface of the spherical crown slides on the second concave spherical surface of the second seat plate, while the first seat plate rotates relative to the ball joint and one end of the first seat plate is raised, causing the first seat plate to tilt. The tilted first seat plate compresses the rigid-flexible assembly and the negative stiffness compression spring, thereby reducing the impact of the horizontal load on the upper structure connection plate, and thus reducing the vibration and lifting of the upper structure connection plate.

[0023] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0024] 1) This invention provides an adaptive anti-lifting device based on negative stiffness compensation, which introduces a negative stiffness compensation component. The rigid-flexible assembly of the negative stiffness compensation component is composed of multiple elastic plates and multiple rigid plates alternately stacked and fixedly connected. This alternating arrangement allows the rigid-flexible assembly to possess both a certain rigidity to bear and transmit force, and elasticity to deform and adapt to different stress conditions. A first groove is formed at the bottom of the rigid-flexible assembly, and a ball joint and multiple negative stiffness compression springs are arranged in this groove. When the negative stiffness compression spring is subjected to force, its stiffness becomes negative, which means that when an external force acts on the spring, the deformation of the spring will increase rather than decrease, thereby absorbing energy. This characteristic allows the negative stiffness spring to effectively reduce vibration and impact. The negative stiffness compression spring is combined with a conventional rigid-flexible assembly with positive stiffness to achieve adjustment and compensation of the overall stiffness. The negative stiffness compression spring and the rigid-flexible assembly can work together to abrade or eliminate the impact on the lower foundation of the building when it is impacted, passing through the second plate, The force transmitted from the spherical cap and the first base plate to the upper structural connecting plate reduces the vibration and lifting of the upper structural connecting plate, so that the upper structural connecting plate is minimally or almost unaffected. The upper structure of the building supported by the upper structural connecting plate is also minimally affected. This invention uses the elastic force of the negative stiffness compression spring and the rigid-flexible combination to balance the lifting force, which can avoid the problem caused by the overall lifting of the building's upper structure due to the self-adaptive anti-lifting device. It significantly improves the safety of the structure under extreme loads, and is especially suitable for situations where loads such as earthquakes and strong winds act on the lower foundation of the building.

[0025] 2) Unlike traditional passive anti-lift devices, the adaptive anti-lift device based on negative stiffness compensation of this invention allows the rigid-flexible assembly and negative stiffness compression spring of the negative stiffness compensation component to dynamically and adaptively undergo elastic deformation (stiffness adjustment) according to the actual force and displacement state. Under different load conditions, such as the action of seismic waves or impact loads of different intensities, the force conditions of each component of the adaptive anti-lift device will change in real time. The elastic plate and rigid plate in the rigid-flexible assembly will deform accordingly after being subjected to force, and this deformation will change the overall stiffness characteristics of the negative stiffness compensation component. At the same time, the spherical hinge rotational connection allows the first seat plate to rotate and displace within a small range, further prompting the automatic adjustment of the stiffness of the negative stiffness compensation component, realizing adaptive adjustment for different working conditions, and avoiding the problems of excessive or insufficient constraint that may occur in traditional fixed stiffness devices under different loads.

[0026] 3) The adaptive anti-lifting device based on negative stiffness compensation of this invention combines the original seismic isolation function of the friction pendulum seismic isolation bearing with the seismic isolation function of the negative stiffness compensation component. The friction pendulum seismic isolation bearing mainly relies on the sliding friction of the spherical cap on the second bearing plate and its own oscillation principle to achieve seismic isolation. The negative stiffness compensation component of this invention is cleverly integrated with the friction pendulum seismic isolation bearing in its design and layout, and their mechanical effects in the horizontal and vertical directions are coordinated with each other. Under the action of horizontal seismic force, the spherical cap can still slide freely on the second bearing plate, dissipating seismic energy through sliding friction, and using the gravity of the superstructure to achieve automatic post-earthquake reset, prolonging the natural vibration period of the structure and reducing the transmission of seismic force to the structure. The negative stiffness compensation component mainly works synergistically in the vertical and lateral directions to prevent lifting and assist in adjusting stiffness, without causing excessive interference to the horizontal sliding and oscillation of the spherical cap, thereby ensuring that the seismic isolation effect of the friction pendulum seismic isolation bearing can be properly performed during normal use, and achieving an effective unity of anti-lifting and seismic isolation functions.

[0027] 4) The adaptive anti-lift device based on negative stiffness compensation of this invention significantly improves the overall performance and reliability of the structure under extreme loads through the combined effects of preventing lift, dynamically adjusting the stiffness of the negative stiffness compensation, and maintaining seismic isolation. For large structures such as bridges and high-rise buildings, this performance improvement means that the structure can better maintain stability in the face of earthquake disasters, reducing the risk of local or overall damage, and lowering maintenance costs and disaster losses. At the same time, reliable structural performance also helps to enhance the service life and safety of buildings. Attached Figure Description

[0028] Figure 1 This is a three-dimensional schematic diagram of the present invention;

[0029] Figure 2 This is the front view of the present invention;

[0030] Figure 3 This is a schematic diagram of the present invention after a portion has been removed;

[0031] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0032] 1. Upper structure connecting plate; 2. Friction pendulum seismic isolation support; 3. Negative stiffness compensation component; 4. Ball joint; 5. Cable; 6. Elastic plate; 7. Rigid plate; 8. Adaptive swing block; 9. Middle connecting plate; 10. First ear plate; 11. Upper curved surface sliding connecting plate; 12. Upper curved surface sliding layer; 13. Spherical cap; 14. Lower curved surface sliding layer; 15. Lower curved surface sliding connecting plate; 16. Lower curved surface sliding limit seat; 17. Negative stiffness compression spring; 18. Second ear plate; 19. Third ear plate; 20. Rigid-flexible assembly; 21. First seat plate; 22. Second seat plate. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Reference Figures 1-3 An adaptive anti-lifting device based on negative stiffness compensation includes a friction pendulum isolation support 2 and a negative stiffness compensation component 3. The friction pendulum isolation support 2 includes a first seat plate 21, a spherical cap 13, and a second seat plate 22 arranged sequentially from top to bottom. The bottom of the first seat plate 21 is provided with a first concave spherical surface, the top of the spherical cap 13 is provided with a first convex spherical surface that contacts the first concave spherical surface, the top of the second seat plate 22 is provided with a second concave spherical surface, and the bottom of the spherical cap 13 is provided with a second convex spherical surface that contacts the second concave spherical surface.

[0035] The negative stiffness compensation component 3 includes an upper structural connecting plate 1, a rigid-flexible assembly 20, negative stiffness compression springs 17, a ball joint 4, and a cable. The rigid-flexible assembly 20 is located between the upper structural connecting plate 1 and the first base plate 21 and is fixedly connected to both the upper structural connecting plate 1 and the first base plate 21. The rigid-flexible assembly 20 includes multiple plates stacked and fixedly connected together. These plates include multiple elastic plates 6 and multiple rigid plates 7, with the elastic plates 6 and rigid plates 7 arranged alternately. A first groove is formed at the bottom of the rigid-flexible assembly 20, and the bottom wall of the first groove is part of the bottom surface of one of the rigid plates 7. The ball joint 4 and multiple negative stiffness compression springs 17 are arranged in the first groove. The upper ends of the negative stiffness compression springs 17 are all fixedly connected to the bottom wall of the first groove, and the lower ends are all connected to the first base plate 21. Each negative stiffness compression spring 17 is in a compressed state. The upper end of the ball joint 4 is fixedly connected to the bottom wall of the first groove, and the lower end of the ball joint 4 extends into the second groove at the top of the first base plate 21. The lower end of the ball joint 4 is rotatably connected to the first base plate 21. There are multiple cables, and these cables surround the rigid-flexible assembly 20, which can protect the rigid-flexible assembly 20 and effectively prevent the separation of the elastic plate 6 and the rigid plate 7 of the rigid-flexible assembly 20. Each cable is in a pre-tensioned state, and the upper and lower ends of each cable are respectively connected to the upper structure connecting plate 1 and the first base plate 21.

[0036] The superstructure connecting plate 1 is rigidly connected to the superstructure of the building (such as bridge beams or building superstructure) using high-strength bolts, ensuring a stable connection between the device and the superstructure and achieving effective force transmission. Simultaneously, mounting holes can be provided for bolt connection with the rigid-flexible assembly 20, forming a tight assembly system. High-strength alloy steel, such as Q345D or 40Cr, is selected, possessing high yield strength and tensile strength, capable of withstanding large loads and not easily deformed, ensuring the reliability and stability of the connection.

[0037] Under normal structural conditions, cable 5 maintains its pre-tensioned state without affecting the seismic isolation performance of the device. By adjusting the length and pretension of the cable, it effectively limits the lifting of the adaptive anti-lifting device under different load conditions. One end of the cable is anchored to the first base plate 21 through an anchor to ensure that the cable will not slip under the ultimate load. Cable 5 can be made of high-strength steel wire twisted together, such as 18×7 type steel wire rope (i.e., the steel wire rope is composed of 18 strands, each strand containing 7 steel wires), with an outer layer wrapped in a wear-resistant and corrosion-resistant polyethylene sheath, and the inside filled with lubricating grease to ensure that the cable has high tensile strength, good flexibility and long service life.

[0038] The ball joint 4 can be made of alloy structural steel, such as 20CrMnTi, which is carburized and quenched to have high surface hardness, good wear resistance, and strong internal toughness, meeting the requirements of the ball joint 4 under complex stress conditions.

[0039] The negative stiffness spring 17 alters the equivalent stiffness of the entire adaptive lifting device. For the adaptive lifting device, a decrease in equivalent stiffness correspondingly lengthens the structure's natural period. Under seismic loading, the difference between the structure's natural period and the dominant period of the seismic motion affects the structure's response. When the dominant period of the seismic motion is shorter than the structure's natural period, the seismic force on the structure decreases. By introducing the negative stiffness spring 17, the equivalent stiffness of the adaptive lifting device is reduced, effectively lengthening its natural period. This significantly reduces the adaptive lifting device's response during earthquakes, decreasing the transmission of seismic energy to the adaptive lifting device and the superstructure above it, thus improving the building's seismic isolation performance.

[0040] During the dynamic stiffness adjustment process, the negative stiffness spring 17 can keep the seismic isolation system in an optimal state according to different load conditions. Under small seismic swaying forces, the stiffness change of the negative stiffness spring 17 is relatively small, and the seismic isolation system maintains a moderate stiffness, which can ensure the stability of the structure while allowing a certain amount of deformation to dissipate energy. However, under strong earthquakes that cause large swaying forces, the stiffness of the negative stiffness spring 17 continues to decrease, and at the same time, it absorbs and dissipates more seismic energy through its elastic deformation.

[0041] The rigid-flexible assembly 20 is composed of multiple elastic plates 6 and rigid plates 7 stacked alternately and fixedly connected, possessing a certain positive stiffness. A negative stiffness spring 17 interacts with the rigid-flexible assembly 20, using its negative stiffness characteristics to offset or neutralize some of the positive stiffness of the rigid-flexible assembly, thus achieving a moderate overall stiffness for the entire negative stiffness compensation component 3. This interaction allows the stiffness of the entire stiffness compensation component 3 to be dynamically adjusted according to actual stress conditions, ensuring the stability of the stiffness compensation component 3 while also reducing stiffness when needed to achieve vibration isolation and anti-lifting functions.

[0042] The negative stiffness compensation component 3 optimizes the stiffness characteristics of the entire system through the special mechanical properties of the negative stiffness spring 17. The negative stiffness characteristic of the negative stiffness spring 17 allows the entire system to better adapt to different working conditions when subjected to loads, reducing the overall stiffness of the system, extending the natural vibration period of the structure, and reducing the transmission of seismic energy. The stiffness of the entire negative stiffness compensation component will dynamically change within a certain range according to the actual working conditions.

[0043] The spherical cap 13 can be made of surface-hardened alloy steel, such as nitrided 42CrMo steel, which has high surface hardness, good wear resistance, and good internal toughness, and can withstand greater pressure and friction, ensuring normal operation under complex stress conditions.

[0044] The cables 5 are in a pre-tensioned state. Multiple cables 5 further connect the first base plate 21, the rigid-flexible assembly 20, and the upper structure connecting plate 1 into a whole. This can limit the vertical and horizontal movement of the upper structure connecting plate 1. When an impact causes one end of the first base plate 21 to lift, the cables 5 at the other end of the first base plate 21 will exert a downward tension on the upper structure connecting plate 1 through their tension. The pre-tension increases, and this increased tension will directly exert a downward tension on the upper structure connecting plate 1 to resist the lifting of the upper structure connecting plate 1 and help the upper structure connecting plate 1 maintain stability in a horizontal position. This reduces the vibration and lifting amplitude of the upper structure connecting plate 1 and converts some of the impact energy into the elastic deformation energy of the cables 5, achieving an energy dissipation effect.

[0045] Cable 5 is typically made of a material with a certain degree of elasticity, such as high-strength steel wire twisted together. During impact, cable 5 is further stretched, resulting in elastic deformation. This elastic deformation can absorb and dissipate some of the impact energy. After the impact, cable 5 will return to its original shape within its elastic range, dissipating the absorbed energy as heat, thereby reducing the impact energy transmitted to the upper continuous plate 1. When cable 5 is subjected to impact and stretching, relative motion occurs between the steel wires inside and between the wires and the strands, which induces friction. The friction process converts some mechanical energy into heat energy, thus consuming impact energy and reducing the impact on the entire structure.

[0046] The cable 5 works in conjunction with other components such as the negative stiffness compression spring 17, the rigid-flexible assembly 20, and the ball joint 4. When an impact causes the first seat plate 21 to tilt and rise or tend to rise, the tension change of the cable 5 when the first seat plate 21 compresses the rigid-flexible assembly 20 and the negative stiffness compression spring 17 will affect the stress state of the entire negative stiffness compensation component 3, prompting the negative stiffness compensation component 3 to better perform its stiffness adjustment and energy dissipation functions, and jointly reduce the upward transmission of impact energy to the upper structure connecting plate 1 and the upper structure, further enhancing the energy dissipation effect of the entire device.

[0047] When the foundation of a building (such as a highway bridge, railway bridge, or high-rise building) is subjected to impact loads causing the spherical cap 13 to slip, the first base plate 21 and the second base plate 22, both having convex-concave curved surfaces, will cause the first base plate 21 to tilt and lift at one end. This tilting and lifting of the first base plate 21 will compress the rigid-flexible assembly 20 and the negative stiffness compression spring 17. The stiffness of the negative stiffness compression spring 17 will decrease with increasing deformation. Under impact, the tilting and lifting of the first base plate 21 will further compress the negative stiffness compression spring 17, dynamically reducing its stiffness and lowering the overall system stiffness. This helps to prolong the structure's natural vibration period, reduce the upward transmission of impact energy, thereby reducing the vibration amplitude of the upper structure's connecting plate and maintaining its horizontal state. The negative stiffness compression spring 17 absorbs and dissipates part of the impact energy during compression. Through the elastic deformation of the negative stiffness compression spring 17, the impact kinetic energy is converted into the elastic potential energy of the negative stiffness compression spring 17, which is gradually dissipated during subsequent vibration. This reduces the impact energy transmitted to the upper structure connecting plate, lowers its vibration and displacement, and helps maintain the horizontal position of the upper structure connecting plate 1. The negative stiffness compression spring 17 works in conjunction with components such as the ball joint 4 and the cable 5. The ball joint 4 allows the first seat plate 21 to rotate to a limited extent under impact. Through the cooperation of the negative stiffness compression spring 17, the rigid-flexible assembly 20, the ball joint 4, and the cable 5, the impact of the load on the upper structure connecting plate 1 is reduced, thereby reducing the vibration and lifting of the upper structure connecting plate 1. This allows the upper structure connecting plate 1 to remain horizontal and not lift, and basically has no impact on the superstructure of the building.

[0048] Therefore, the adaptive anti-lifting device of the present invention can effectively offset and reduce the impact and load from the lower foundation of the building upwards, so that the upper structure connecting plate 1 will not experience large swaying, tilting and lifting, thus affecting the stability of the upper structure of the building.

[0049] Furthermore, the first base plate 21 includes an adaptive swing block 8, a middle connecting plate 9, an upper curved sliding connecting plate 11, and an upper curved sliding layer 12, which are arranged sequentially from top to bottom and fixedly connected together. The edge of the middle connecting plate 9 extends beyond the edge of the adaptive swing block 8 and the edge of the upper curved sliding connecting plate 11, respectively. The lower end of each cable is fixedly connected to the middle connecting plate, and the first concave spherical surface is disposed at the bottom of the upper curved sliding layer 12.

[0050] The adaptive swing block 8 is located at the top of the first base plate 21. It can make certain adaptive adjustments according to the swing trend of the superstructure under loads such as earthquakes, so that the entire device can better coordinate with the movement of the superstructure. The edge of the middle connecting plate 9 extends beyond the edge of the adaptive swing block 8 and the upper curved sliding connecting plate 11. This design facilitates the connection of the cables. The lower end of the cables can be fixedly connected to the middle connecting plate 9, thereby connecting the upper structure connecting plate 1 and the first base plate 21 more tightly through the cables, enhancing the stability of the overall structure. The upper curved sliding connecting plate 11 and the upper curved sliding layer 12 are in contact with the bottom of the spherical cap 13. The bottom of the upper curved sliding layer 12 is provided with a first concave spherical surface, which cooperates with the first convex spherical surface at the top of the spherical cap 13 to form a stable sliding friction pair, ensuring that the spherical cap 13 can slide smoothly in the horizontal direction and achieve the seismic isolation function.

[0051] The middle connecting plate 9 can be made of the same high-strength alloy steel as the upper connecting plate to ensure sufficient strength and rigidity, and to reliably transfer and distribute the load.

[0052] The upper curved sliding connecting plate 11 and the upper curved sliding layer 12 further optimize the sliding friction conditions of the friction pendulum seismic isolation bearing 2. The first concave spherical surface at the bottom of the upper curved sliding layer 12 is in close contact with the first convex spherical surface at the top of the spherical cap 13. Under horizontal loads such as earthquakes, the spherical cap 13 can slide smoothly on this sliding surface, reducing energy loss and improving the seismic isolation effect. At the same time, this layered structure allows for the selection of appropriate materials and surface treatment processes according to different needs. For example, using a material with a low coefficient of friction in the upper curved sliding layer 12 further reduces frictional resistance, enhances seismic isolation performance, and better protects the structure from the impact of seismic energy.

[0053] The upper curved sliding connection plate 11 can be made of stainless steel, such as 304 stainless steel, which has good corrosion resistance and strength and can be used for a long time in harsh environments such as ocean and humidity, ensuring the reliability and stability of the connection.

[0054] The upper surface of the upper curved sliding layer 12 is connected to the upper curved sliding connecting plate 11 by an embedded connection or adhesive bonding. The lower surface of the layer and the spherical cap 13 are surface-treated with a low-friction coefficient coating (such as a molybdenum disulfide coating) to form a good sliding contact interface and reduce sliding resistance. High-strength nylon material can be used, which has good self-lubricating properties, wear resistance, and corrosion resistance, and can maintain good performance during long-term sliding, reduce wear, and extend service life.

[0055] Furthermore, the adaptive swing block 8 includes a polytetrafluoroethylene block and a stainless steel block arranged from top to bottom and fixedly connected together, and the second groove is disposed on the polytetrafluoroethylene block.

[0056] The PTFE block possesses excellent self-lubricating properties and a low coefficient of friction, effectively reducing frictional resistance between contacting components and allowing the adaptive swing block 8 to adjust its posture more flexibly. The stainless steel block, with its high strength and rigidity, provides sufficient support and stability for the entire adaptive swing block 8, preventing excessive deformation under stress. Furthermore, a second groove is provided on the PTFE block, which engages with the lower end of the ball joint 4 to form a low-friction rotating connection pair, further improving the vertical and lateral rotational flexibility of the first base plate 21 and helping the device better adapt to structural deformation and movement requirements.

[0057] The application of PTFE blocks significantly reduces the frictional resistance experienced by the adaptive swing block 8 during its swing, thereby enabling it to respond more sensitively to the movement changes of the first base plate 21. Under loads such as earthquakes, the movement of the building's foundation is often complex and variable. The low-friction adaptive swing block 8 can adjust its posture in a timely and accurate manner, allowing the entire adaptive anti-lift device to better coordinate with the movement of the building's foundation, thus improving the seismic isolation and anti-lift effects.

[0058] The use of stainless steel blocks ensures that the adaptive swing block 8 possesses both low friction characteristics and sufficient strength and stiffness to withstand the loads transmitted from the building's foundation. Under extreme loads such as earthquakes, the building's foundation exerts significant pressure, shear force, and additional dynamic effects due to inertia on the adaptive anti-lift device. The stainless steel blocks effectively resist deformation and damage caused by these loads, ensuring the integrity and reliability of the adaptive swing block 8. This allows the device to maintain stable performance during long-term load bearing and frequent movement, preventing damage or deformation of the adaptive swing block 8 from affecting the normal operation of the entire device.

[0059] Furthermore, the second base plate 22 includes a lower curved sliding layer 14, a lower curved sliding connecting plate 15, and a lower curved sliding limiting seat 16 arranged sequentially from top to bottom and fixedly connected together. The second concave spherical surface is disposed on the top of the lower curved sliding layer 14, and the edge of the lower curved sliding limiting seat 16 is provided with an annular flange for limiting the sliding stroke of the spherical cap 13.

[0060] The top of the lower curved sliding layer 14 is provided with a second concave spherical surface, which cooperates with the second convex spherical surface at the bottom of the spherical cap 13 to form another key sliding friction pair, providing stable support and guidance for the horizontal sliding of the spherical cap 13. The lower curved sliding connecting plate 15 serves as a connection and transition, firmly connecting the lower curved sliding layer 14 and the lower curved sliding limiting seat 16 together. The annular flange provided at the edge of the lower curved sliding limiting seat 16 can effectively limit the horizontal sliding stroke of the spherical cap 13, preventing the spherical cap 13 from sliding off the second seat plate 22 in extreme situations such as strong earthquakes, and avoiding the failure of the adaptive anti-lifting device or even structural damage.

[0061] The fit between the lower curved sliding layer 14 and the bottom of the spherical cap 13 provides a solid foundation for the seismic isolation function of the friction pendulum isolation bearing 2. Its excellent sliding performance and fit ensure that the spherical cap 13 slides smoothly under horizontal seismic forces, effectively prolonging the natural period of the structure and reducing the transmission of seismic energy to the structure.

[0062] The annular flange on the lower curved sliding limit seat 16 is a crucial safety feature. In extreme earthquake events, when the earthquake intensity exceeds expectations or the structure suffers other abnormal loads, the spherical cap 13 may experience significant sliding displacement. The annular flange effectively limits the sliding range of the spherical cap 13, preventing it from slipping off the second seat plate 22 and ensuring that the adaptive anti-lift device maintains a reliable connection with the building's foundation. This avoids serious consequences such as failure of the adaptive anti-lift device and damage to the structural support system due to the spherical cap 13 slipping off, greatly improving the structural safety under extreme conditions.

[0063] The upper surface of the lower curved sliding layer 14 contacts and engages with the spherical cap 13, while the lower surface is connected to the lower curved sliding connecting plate 15 via an embedded connection or adhesive bonding, ensuring a tight connection with the connecting plate and reliable force transmission during sliding. It can be made of high-strength nylon material, similar to the upper curved sliding layer 12, to ensure good sliding performance and wear resistance, adapting to long-term sliding operation.

[0064] The lower curved sliding connecting plate 15 can be made of the same stainless steel material as the upper curved sliding connecting plate 11 to ensure corrosion resistance and strength, adapt to different usage environments, and ensure the reliability and long-term stability of the connection.

[0065] The lower curved sliding limit seat 16 can be made of high-strength cast iron, such as HT300, which has high hardness and wear resistance, and can withstand greater pressure and friction, ensuring the reliability and stability of the limit function.

[0066] Furthermore, the first groove is located in the middle of the rigid-flexible assembly 20, and the negative stiffness compression spring 17 surrounds the ball joint 4. This layout design allows the negative stiffness compression spring 17 to be evenly distributed around the ball joint 4, thereby applying elastic force more evenly to the ball joint 4 and its connected first seat plate 21 when under stress. At the same time, placing the first groove in the middle of the rigid-flexible assembly 20 helps to ensure the overall stability and symmetry of the rigid-flexible assembly 20 under stress, allowing the rigid-flexible assembly 20 to better exert its rigid-flexible mechanical properties and coordinate the force transmission and balance between the negative stiffness compensation component 3 and the friction pendulum vibration isolation support 2.

[0067] The arrangement of the negative stiffness compression spring 17 surrounding the ball joint 4 ensures that forces from all directions are evenly transmitted to the ball joint 4 and the first base plate 21 during operation. This avoids localized stress concentration or excessive deformation caused by uneven force distribution, improving the stability and reliability of the entire negative stiffness compensation assembly 3 and the connected friction pendulum seismic isolation support 2. For example, under multi-directional combined loads caused by an earthquake, the negative stiffness compression spring 17 surrounding the ball joint 4 can provide support forces in multiple directions simultaneously, enabling the device to stably resist various complex forces, reducing swaying and displacement, and ensuring structural safety.

[0068] Placing the first groove in the middle of the rigid-flexible assembly 20 helps optimize the overall mechanical performance of the component. When subjected to forces from above and below, the rigid-flexible assembly 20 efficiently transmits and distributes forces through the rational deformation and synergistic effect of the elastic plate 6 and the rigid plate 7, achieving negative stiffness compensation. This symmetrical and uniform structural layout helps to fully utilize the potential of the rigid-flexible assembly 20, improve its load-bearing capacity and adaptability to different loads, enhance the mechanical performance of the entire device, and better meet the stringent structural performance requirements in engineering practice.

[0069] Furthermore, the lower end of the ball joint 4 is rotatably connected to the first base plate 21 through contact with a spherical, ellipsoidal, or figure-eight curved surface. This diverse range of contact methods provides a flexible design for the connection between the ball joint 4 and the first base plate 21, allowing for optimized selection based on different engineering requirements and force characteristics. Spherical contact provides full rotational freedom, enabling the first base plate 21 to rotate relatively freely in space; ellipsoidal contact can limit the rotation range to some extent while still allowing necessary posture adjustments; figure-eight curved surface contact has unique mechanical properties and motion trajectories, suitable for specific force patterns and motion requirements. Different contact methods ensure good fit and force transmission efficiency between the ball joint 4 and the first base plate 21, guaranteeing the reliability and stability of the rotatable connection.

[0070] Furthermore, the first base plate 21 is provided with a plurality of first ear plates 10, and the second base plate 22 is provided with a second ear plate 18 at a position corresponding to each of the first ear plates 10.

[0071] The first ear plate 10 and the second ear plate 18 provide a convenient interface for the installation, connection, and transportation of the device. During transportation, the first ear plate 10 and the second ear plate 18 can be bolted together to prevent shaking and displacement during transport. When used in high-intensity seismic zones, the bolts on the first ear plate 10 and the second ear plate 18 can act as shear-resistant components; the bolts will break after the impact force reaches a certain magnitude. In addition, the second ear plate 18 can also be used to connect to the lower foundation of a building, ensuring that the second base plate 22 will not shift or loosen during use.

[0072] The first ear plate 10 and the second ear plate 18 can be made of cast steel, such as ZG270-500, which has good casting performance and comprehensive mechanical properties, can withstand large loads and complex stress states, and ensure the reliability of the connection.

[0073] A third ear plate 19 can also be provided on the side of the upper curved sliding connecting plate 11. A high-strength bolt passes through the third ear plate 19 and connects to the middle connecting plate 9, thereby achieving a fixed connection between the upper curved sliding connecting plate 11 and the middle connecting plate 9. Of course, the upper curved sliding connecting plate 11 and the middle connecting plate 9 can also be fixedly connected together by welding.

[0074] Furthermore, the rigid plate 7 is made of high-strength alloy steel, and the elastic plate 6 is made of rubber. Any adjacent rigid plates 7 and elastic plates 6 are bonded together with adhesive and then fixed together by riveting. Some of the upper elastic plates 6 of the rigid-flexible assembly 20 can be made of natural rubber or neoprene rubber, possessing good elastic deformation capacity and aging resistance, capable of generating large elastic deformation under load, providing elastic recovery force. Some of the upper rigid plates 7 of the rigid-flexible assembly 20 can be made of high-quality carbon structural steel, such as No. 45 steel, which undergoes heat treatment to improve hardness and strength, possessing good machinability and load-bearing capacity, effectively transmitting and distributing loads. Some of the lower elastic plates 6 of the rigid-flexible assembly 20 can be made of nitrile rubber, possessing good oil resistance, wear resistance, and aging resistance, capable of generating moderate elastic deformation under load, playing a buffering and energy-dissipating role, further absorbing structural vibration energy. Some of the rigid plates 7 at the bottom of the rigid-flexible assembly 20 can be made of low-alloy high-strength structural steel, such as Q390, which has high strength and good plasticity and toughness, and can withstand large loads, providing a stable support platform for the adaptive swing block 8.

[0075] High-strength alloy steel possesses excellent strength and toughness, enabling it to withstand significant loads and impacts, providing sufficient rigidity support for the entire rigid-flexible assembly 20. The rubber elastic plate 6 exhibits good elasticity and damping characteristics, allowing it to deform considerably under stress and absorb some energy while providing elastic recovery force. The dual fixing method of adhesive bonding and riveting ensures a tight bond between the plates while also withstanding significant shear and tensile forces, guaranteeing that the rigid-flexible assembly 20 will not experience interlayer delamination or misalignment under long-term use and complex stress conditions.

[0076] The combination of alloy steel and rubber gives the rigid-flexible assembly 20 the advantages of high strength, high stiffness, and good elasticity. When facing complex loads such as earthquakes, the rigid plate 7 can withstand the main loads and pressures, maintaining the shape and stability of the entire assembly, while the elastic plate 6 can absorb some energy through deformation, mitigating impact forces and reducing the structure's vibration response. This combination of rigidity and flexibility allows the device to better adapt to different load variations, improving seismic isolation and anti-lifting effects.

[0077] The combination of adhesive bonding and riveting ensures a strong and reliable connection between the rigid plate 7 and the elastic plate 6. During long-term use, even under frequent vibration and deformation conditions, the plates maintain a good bond without loosening or cracking, thus guaranteeing the integrity and mechanical stability of the rigid-flexible assembly 20 and extending the service life of the device.

[0078] Furthermore, the top and bottom of the rigid-flexible assembly 20 both employ elastic plates 6. This design allows the elastic plates 6 at the top and bottom to deform first when the device is subjected to loads from the vertical direction, acting as a buffer and absorbing energy, thus reducing the impact of rigid impacts on the entire assembly. Simultaneously, the deformation of the elastic plates 6 also provides a certain degree of adjustability for the negative stiffness compensation assembly 3, enabling it to better adapt to load changes and achieve adaptive adjustment.

[0079] The top and bottom elastic plates 6 effectively absorb and dissipate energy impacts from the vertical direction, such as vertical vibrations caused by earthquakes and forces generated by changes in structural self-weight. This helps reduce the vibration energy transmitted to the building structure, lower the structural response amplitude, and improve the comfort and safety of the structure. The deformation capacity of the elastic plates 6 allows the negative stiffness compensation component 3 to have a greater adjustment range and flexibility in response to load changes. Under different operating conditions, the elastic plates 6 can deform accordingly based on the actual stress conditions, working in conjunction with other components to achieve more precise stiffness compensation and adjustment, thereby better meeting the structural requirements for stability and seismic isolation performance.

[0080] According to another aspect of the present invention, a method for preventing lifting based on an adaptive anti-lifting device with negative stiffness compensation is also provided, comprising the following steps:

[0081] 1) The upper structure connecting plate 1 is fixedly installed on the upper structure of the building, and the second plate 22 is fixedly installed on the lower structure of the building, wherein the building is a highway bridge, railway bridge or high-rise building;

[0082] 2) When the lower structure of the building is subjected to a horizontal load impact, while the second convex spherical surface of the spherical cap 13 slides on the second concave spherical surface of the second seat plate 22, the first seat plate 21 rotates relative to the ball joint 4 and one end of the first seat plate 21 is raised, causing the first seat plate 21 to tilt. The tilted first seat plate 21 compresses the rigid-flexible assembly 20 and the negative stiffness compression spring 17, thereby reducing the impact force of the horizontal load on the upper structure connecting plate 1, and thus reducing the vibration and lifting of the upper structure connecting plate 1.

[0083] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-adapting anti-lifting device based on negative stiffness compensation, characterized in that, The system includes a friction pendulum isolation bearing and a negative stiffness compensation assembly. The friction pendulum isolation bearing comprises a first base plate, a spherical cap, and a second base plate arranged sequentially from top to bottom. The bottom of the first base plate has a first concave spherical surface, and the top of the spherical cap has a first convex spherical surface that contacts the first concave spherical surface. The top of the second base plate has a second concave spherical surface, and the bottom of the spherical cap has a second convex spherical surface that contacts the second concave spherical surface. The negative stiffness compensation component includes an upper structural connecting plate, a rigid-flexible assembly, a negative stiffness compression spring, a ball joint, and a cable. The rigid-flexible assembly is located between the upper structural connecting plate and the first base plate and is fixedly connected to both the upper structural connecting plate and the first base plate. The rigid-flexible assembly includes multiple plates stacked and fixedly connected together. These plates include multiple elastic plates and multiple rigid plates, with the elastic and rigid plates arranged alternately. A first groove is formed at the bottom of the rigid-flexible assembly, and the bottom wall of the first groove is part of the bottom surface of one of the rigid plates. The ball joint and cable are arranged within the first groove. Multiple negative stiffness compression springs are provided, with the upper end of each spring fixedly connected to the bottom wall of the first groove and the lower end connected to the first base plate. Each spring is in a compressed state. The upper end of the ball joint is fixedly connected to the bottom wall of the first groove, and the lower end extends into the second groove at the top of the first base plate. The lower end of the ball joint is rotatably connected to the first base plate. Multiple cables surround the rigid-flexible assembly. Each cable is in a pre-tensioned state, and the upper and lower ends of each cable are respectively connected to the upper structure connecting plate and the first base plate.

2. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The first base plate includes an adaptive swing block, a middle connecting plate, an upper curved sliding connecting plate, and an upper curved sliding layer, which are arranged and fixedly connected together from top to bottom. The edge of the middle connecting plate extends beyond the edge of the adaptive swing block and the edge of the upper curved sliding connecting plate, respectively. The lower end of each cable is fixedly connected to the middle connecting plate, and the first concave spherical surface is disposed at the bottom of the upper curved sliding layer.

3. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 2, characterized in that, The adaptive swing block includes a polytetrafluoroethylene block and a stainless steel block arranged from top to bottom and fixedly connected together, and the second groove is disposed on the polytetrafluoroethylene block.

4. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The second base plate includes a lower curved sliding layer, a lower curved sliding connecting plate, and a lower curved sliding limiting seat arranged sequentially from top to bottom and fixedly connected together. The second concave spherical surface is disposed on the top of the lower curved sliding layer, and the edge of the lower curved sliding limiting seat is provided with an annular flange for limiting the sliding stroke of the spherical cap.

5. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The first groove is located in the middle of the rigid-flexible assembly, and the negative stiffness compression spring surrounds the ball joint.

6. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The lower end of the ball joint is rotatably connected to the first base plate through contact with a spherical, ellipsoidal, or figure-eight shaped curved surface.

7. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The first base plate is provided with a plurality of first ear plates, and the second base plate is provided with a second ear plate at a position corresponding to each of the first ear plates.

8. A self-adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The rigid plate is made of high-strength alloy steel, and the elastic plate is made of rubber. Any adjacent rigid plates and elastic plates are bonded together with adhesive and then fixed together by riveting.

9. The adaptive anti-lifting device based on negative stiffness compensation according to claim 1, characterized in that, The top and bottom of the rigid-flexible assembly are both made of elastic plates.

10. A method for preventing lifting based on an adaptive anti-lifting device with negative stiffness compensation, characterized in that, Includes the following steps: 1) The upper structure connecting plate is fixedly installed on the upper structure of the building, and the second plate is fixedly installed on the lower structure of the building, wherein the building is a highway bridge, railway bridge or high-rise building; 2) When the lower structure of the building is subjected to a horizontal load impact, the second convex spherical surface of the spherical crown slides on the second concave spherical surface of the second seat plate, while the first seat plate rotates relative to the ball joint and one end of the first seat plate is raised, causing the first seat plate to tilt. The tilted first seat plate compresses the rigid-flexible assembly and the negative stiffness compression spring, thereby reducing the impact of the horizontal load on the upper structure connection plate, and thus reducing the vibration and lifting of the upper structure connection plate.

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