Anti-overturning variable stiffness ramp friction isolation bearing and design method thereof

Abstract

The application discloses an anti-overturning variable-rigidity slope friction isolation bearing and a design method thereof. The bearing comprises two orthogonally arranged base assemblies providing bidirectional self-resetting functions, and a sliding connection assembly is arranged between the two base assemblies and can slide between the base assemblies. Each base assembly comprises a base limiting device and a base provided with different inclination sliding rails. The base provided with different inclination sliding rails comprises outer sliding rails and inner sliding rails. The inner sliding rails are arranged between the outer sliding rails. The outer sliding rails and the inner sliding rails are both V-shaped slopes, and the inclination angle of the V-shaped slope of the outer sliding rails is greater than that of the V-shaped slope of the inner sliding rails. The application can balance the contradiction between the isolation rate and the displacement of the isolation layer by designing the different inclination angles and friction coefficients of the inner and outer sliding rails. Meanwhile, the bearing is prevented from being pulled off when the bearing is locally pulled or the bearing is pulled off due to the inertia of the upper structure, thereby playing an anti-overturning role.

Description

TECHNICAL FIELD

[0001] The present application relates to an anti-overturning variable stiffness inclined plane frictional isolation bearing and a design method thereof, and belongs to the technical field of isolation control of vibration-sensitive and overturning-prone electrical equipment. BACKGROUND

[0002] Frictional sliding isolation is originally composed of a frictional sliding mechanism for isolating seismic action and a damping centripetal mechanism for limiting and resetting, and is mostly a planar sliding isolation system. However, the system cannot reset itself, and a resetting device needs to be additionally provided to improve the self-resetting performance. In the 1980s, the University of California, Berkeley, developed a friction pendulum isolation device, which is called a friction pendulum system / bearing (FPS / FPB). The device has low sensitivity and high stability to the frequency range of seismic excitation, and has a self-resetting function due to its unique circular sliding, and can perform a pendulum-like motion during operation, thereby prolonging the natural period of the isolated structure, avoiding the predominant period of the earthquake, and converting kinetic energy into heat energy through the friction pair of the bearing to reduce the impact of the earthquake on the structure, but still has the problem of residual displacement of the bearing that is difficult to eliminate. With the development of isolation technology, inclined plane frictional bearings have become a research hotspot due to their stable restoring force and the ability to completely eliminate residual displacement.

[0003] However, the sliding surface of the traditional inclined plane isolation bearing has a single inclination angle, and it is difficult to balance the isolation effect and control the displacement of the isolation layer. When the inclination angle of the sliding surface is reduced, the bearing can achieve a small starting acceleration, ensuring the isolation effect of the bearing under small earthquakes, but it is easy to cause large displacement of the isolation layer under large earthquakes or long-period earthquakes, which threatens the safety of the isolation layer. To prevent the sliding block from leaving the track, the sliding rail needs to be lengthened, which increases the size and cost of the isolation bearing. When the inclination angle of the sliding surface is increased, the displacement of the isolation layer can be effectively controlled, but the starting acceleration is increased, the isolation effect under small earthquakes is reduced, and the impact effect of the sliding block passing through the inclined plane transition point is also amplified, which reduces the isolation effect. Based on the above, a variable stiffness inclined plane frictional isolation bearing is developed to make up for the shortcomings of the traditional inclined plane frictional isolation bearing and balance the isolation effect and the displacement of the isolation layer.

[0004] Furthermore, the small inclination angle and friction coefficient of the inner sliding rail can ensure the isolation effect of the bearing under small earthquakes, and the inclination angle of the inner sliding rail also plays a transition role. By increasing the inclination angle and friction coefficient of the outer sliding rail, the displacement of the isolation layer can be effectively controlled, and the stability and applicability of the bearing are improved by reducing the instantaneous impact of the sliding connection component passing through the discontinuous inclined plane.

[0005] For some electrical equipment, such as converter valve using bottom support structure, high gravity center makes it very sensitive to vibration, horizontal vibration easily leads to failure of support structure, vertical vibration easily leads to damage of upper power module, coupling effect of horizontal and vertical vibration easily causes local tension of isolation layer and lifting of isolation bearing. The existing inclined plane friction isolation bearing has low uplift resistance, and is difficult to meet the demand of electrical equipment for uplift resistance and overturning resistance, which easily causes damage of electrical equipment under strong earthquake, and seriously affects the promotion and use of isolation technology in the field of electrical isolation. SUMMARY

[0006] In view of the above problems, the present application provides an anti-overturning variable stiffness inclined plane friction isolation bearing and a design method thereof, which takes into account the advantages of traditional inclined plane friction isolation bearing and makes up for the shortcomings of traditional inclined plane friction isolation bearing, so as to balance the isolation effect and displacement of isolation layer. The upper and lower base assemblies arranged in quadrature are connected with the upper equipment and lower structure, and the sliding connection assembly is arranged between the upper and lower bases to reduce the transmission of seismic energy to the upper structure and ensure the normal work of the isolation structure under earthquake action. When the isolation bearing is locally tensioned or tends to be lifted due to inertia of the upper structure, the lifting of the bearing is prevented, and the bearing has wider applicability and higher reliability compared with the traditional inclined plane friction bearing.

[0007] The above object is achieved by the following technical solutions.

[0008] The present application first provides an anti-overturning variable stiffness inclined plane friction isolation bearing, which comprises two orthogonally arranged base assemblies providing bidirectional self-resetting function, and a sliding connection assembly arranged between the two base assemblies and capable of sliding between the base assemblies. Each base assembly comprises a base limiting device and a base provided with different inclined sliding rails. The base provided with different inclined sliding rails comprises outer sliding rails and inner sliding rails. The inner sliding rails are arranged between the outer sliding rails. The outer sliding rails and the inner sliding rails are both V-shaped inclined planes, and the V-shaped inclined plane of the outer sliding rails has a larger inclination angle than that of the inner sliding rails.

[0009] The upper half and the lower half of the sliding connection assembly have the same structure but a phase difference of 90°. The upper half and the lower half of the sliding connection assembly both have the following structure: recess-shaped assembly limiting devices are arranged on both sides to cooperate with the base limiting devices of the base assemblies to prevent the bearing from being lifted, and outer sliding connection assembly friction pairs are arranged on both sides to slide on the base limiting devices of the base assemblies. Inner sliding rail friction pairs and outer sliding rail friction pairs are arranged on both sides of the middle sliding connection assembly to slide on the inner sliding rails and the outer sliding rails of the upper and lower base assemblies, respectively.

[0010] Further, the sliding friction coefficient between the outer sliding rail friction pairs and the outer sliding rails is μout The sliding friction coefficient between the inner side sliding rail friction pair and the inner side sliding rail is μ in , μ out > μ in .

[0011] Further, the base assembly is externally provided with a base fixing angle steel, and bolt holes are arranged on the base assembly and the base fixing angle steel to bolt connect the base assembly with the structure.

[0012] Further, the two ends of each base assembly are provided with lateral limiting devices, and the inner side of the lateral limiting device is provided with a lateral limiting rubber gasket.

[0013] The application also provides a design method of the anti-overturning variable rigidity slope friction isolation bearing, and the method comprises the following steps:

[0014] S1. According to the isolation requirement of the isolation structure, the design displacement D c-in of the inner side sliding rail of the isolation bearing is determined max ;

[0015] S2. The friction coefficients μ in , μ out of the inner side sliding rail and the outer side sliding rail are initially determined, and then the inclination angles θ in , θ out of the inner side sliding rail and the outer side sliding rail are designed, and it is required to ensure that μ in < tan θ in , μ out < tan θ out to ensure the self-resetting performance of the bearing after the earthquake;

[0016] S3. The mechanical model of the bearing is established, and the stress conditions of the inner side sliding rail and the outer side sliding rail under different displacement stages are analyzed as follows:

[0017] The starting force F start of the sliding between the base assembly and the sliding connection assembly is as shown in formula (1):

[0018] F start = W (sin θ in + μ in cos θ in ) (13)

[0019] The initial rigidity K in is as shown in formula (2):

[0020]

[0021] In the formula, W is the vertical load; h inThe vertical distance from the center of mass of the sliding connection assembly to the sliding surface of the inner sliding rail;

[0022] Restoring force F reset As shown in equation (3):

[0023] F reset = W (sinθ in - μ in cosθ in ) (15)

[0024] As shown in equation (1), by reducing θ in and μ in , F start can be reduced, so that the structure can start sliding under a slight earthquake, avoiding brittle response;

[0025] As shown in equation (2), low inclination θ in and low friction coefficient μ in design so that the initial stiffness K in is at a low level, matching the flexible isolation requirement under the frequently occurring earthquake;

[0026] As shown in equation (3), when the inner sliding rail is unloaded, the gravity component (Wsinθ in ) drives the slider to return, and the low friction coefficient (μ in < tanθ in ) ensures that the restoring force is always greater than zero;

[0027] When the displacement value exceeds the critical value D c-in , the outer sliding rail is involved, and its equivalent stiffness K out is approximately:

[0028]

[0029] As shown in equation (4), by increasing the inclination and friction coefficient of the outer sliding rail, a larger restoring force and secondary yield stiffness can be achieved, and the isolation layer displacement can be effectively controlled; higher θ out and μ out make K out at a high level, forming a significant secondary stiffness platform to suppress displacement growth under a large earthquake; at the same time, the inclination θ out of the outer sliding rail increases, resulting in an increase in the gravity component;

[0030] S4. Calculate the length of the inclined surface required by each sliding rail to ensure that no derailment or stress overrun occurs under the designed displacement, and the inclined surface length calculation formula is shown in equations (5) and (6);

[0031]

[0032] In the formula, L inL is the required slope length for the inner side sliding rail out D is the required slope length for the outer side sliding rail c-in D is the inner side design displacement max D is the maximum design displacement, determined according to the specification or time-history analysis structure under rare earthquake safe D is the safety capacity to prevent derailment

[0033] S5. Use genetic algorithm, combine maximum energy dissipation objective function and constraint conditions to carry out parameterized analysis and numerical simulation verification, realize the determination and optimization of the slope length; specifically, the maximum energy dissipation objective function is constructed as follows:

[0034] The energy dissipation capacity is measured by the area enclosed by the hysteresis curve, and the total energy dissipation E total is expressed as formula (7)-formula (9):

[0035] E total = E in + E out (19)

[0036] E in = 4μ in WD c-in (20)

[0037] E out = 4μ out W(D max -D c-in ) (21)

[0038] In the formula, the coefficient 4 represents the energy dissipation of a complete hysteresis cycle, E in represents the inner side sliding rail friction energy dissipation, E out represents the outer side sliding rail friction energy dissipation

[0039] The constraint conditions include the following:

[0040] Sliding rail self-resetting condition:

[0041] μ in <tanθ in ; μ out <tanθ out (22)

[0042] Contact stress safety limit:

[0043]

[0044] In the formula, A 滑块 is the contact area of the sliding connection assembly and the sliding rail; f allow is the material allowable stress

[0045] Slide rail length feasibility:

[0046] L in cosθ in +L out cosθ out ≥D max +△L safe (24)

[0047] The beneficial effects of the present application compared with the prior art are:

[0048] 1、The entire support of the present application adopts an assembled structure, the base is an integral whole, different inclination angles of the inner and outer slide rails are realized through a machining process, after the sliding connection assembly is placed into the base, the base limiting device and the base fixed angle steel are sequentially bolted with the base, and the lateral limiting rubber gasket and the lateral limiting device are bolted with the base in the same way. In use, the shock isolation structure is bolted with the upper base, the lower base is bolted with the ground or other equipment, the sliding connection assembly is arranged between the upper and lower bases, the sliding friction of the support reduces the transmission of seismic energy to the upper structure during an earthquake, and the horizontal shock isolation effect is achieved. Through the design of different inclination angles and friction coefficients of the inner and outer slide rails, the contradiction between the isolation rate and the displacement of the isolation layer can be balanced. At the same time, when the support is subjected to local tension or tends to be pulled away due to the inertia of the upper structure, the base limiting device and the sliding connection assembly limiting device cooperate with each other to prevent the support from being pulled away, and the anti-overturning effect is achieved. The present application can realize smaller starting force and lower initial stiffness by designing the inclination angle and friction coefficient of the inner slide rail, and can realize complete self-resetting after the earthquake. By increasing the inclination angle and friction coefficient of the outer slide rail, a larger restoring force and a secondary yield stiffness can be realized, and the displacement of the isolation layer can be effectively controlled, thereby reducing the influence on the upper structure.

[0049] 2、The inclined sliding surface structure of the support slide rail helps to reduce the base shear of the structure during operation, and significantly reduces the inter-story drift angle of the structure at the epicenter. By designing different inclination angles and friction coefficients of the inner and outer slide rails, the contradiction between the isolation rate and the displacement of the isolation layer can be effectively balanced.

[0050] 3、The length of the inclined surface of the inner and outer slide rails can be optimized to the optimal solution by simulating the isolation structure type. After the design parameters of the isolation structure are determined according to the requirements, a mechanical model of the support is established, the stress conditions of the inner and outer slide rails under different displacement stages are analyzed, the length of the slide rail inclined surface is preliminarily calculated, and then an optimization algorithm (genetic algorithm, etc.) is used to perform parameterized analysis and numerical simulation verification in combination with an objective function (maximum energy consumption, etc.) and constraint conditions (design displacement not exceeding the length of the inclined surface, stress overrun, etc.), so that the length of the inclined surface is scientifically determined and optimized, and the isolation performance and engineering economy are taken into account.

[0051] 4. By setting multiple inclination angles, smooth transition between the slopes is achieved, reducing the instantaneous impact when the sliding connection assembly passes through discontinuous slopes, and the variable stiffness characteristics of the support can effectively prevent resonance and improve the stability and applicability of the slope friction isolation bearing.

[0052] 5. The sliding connection assembly limiting device and the base limiting device cooperate with each other to prevent the isolation bearing from being pulled off when the isolation bearing is subjected to local tension or the inertia of the upper structure causes the bearing to be pulled off.

[0053] 6. The friction pair is polytetrafluoroethylene friction material, which can dissipate seismic energy during sliding friction.

[0054] 7. The entire support adopts an assembled structure, facilitating the replacement of damaged parts and the restoration of support functions after an earthquake, and reducing the maintenance cost of the support after an earthquake.

[0055] 8. The support can also achieve bidirectional vibration reduction independent design, and can achieve bidirectional isolation independent design for structures with large differences in bidirectional mechanical properties, improving the isolation effect of the support. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is a schematic diagram of the overall structure of the present application;

[0057] Figure 2 is a schematic diagram of the sliding connection assembly structure of the present application;

[0058] Figure 3 is a schematic diagram of the base assembly of the present application;

[0059] Figure 4 is a sectional view of the support and the sliding connection assembly of the present application;

[0060] Figure 5 is a sectional view of the base device and the sliding connection assembly limiting device cooperating with each other of the present application;

[0061] Figure 6 is a schematic diagram of the slope-related parameters of the support of the present application.

[0062] Explanation of reference numerals in the drawings: 1, base assembly; 1.1, base limiting device; 1.2, inner slide rail; 1.3, outer slide rail; 2, base fixed angle steel; 3, lateral limiting rubber gasket; 4, lateral limiting device; 5, sliding connection assembly; 5.1, inner slide rail friction pair; 5.2, outer slide rail friction pair; 5.3, outer friction pair of the sliding connection assembly; 5.4, sliding connection assembly limiting device; 6, bolt hole; 7, bolt. DETAILED DESCRIPTION

[0063] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0064] like Figures 1 to 5 As shown, an anti-overturning variable stiffness inclined friction seismic isolation bearing of this embodiment includes two orthogonally arranged base assemblies 1 that provide bidirectional self-resetting function. A sliding connection assembly 5 is provided between the two base assemblies 1, which can slide between the base assemblies 1. Each base assembly 1 includes a base limiting device 1.1 and a base with slide rails of different inclination angles. The base with slide rails of different inclination angles includes an outer slide rail 1.3 and an inner slide rail 1.2. The inner slide rail 1.2 is disposed between the two outer slide rails 1.3. Both the outer slide rail 1.3 and the inner slide rail 1.2 are V-shaped inclined surfaces, and the inclination angle of the V-shaped inclined surface of the outer slide rail 1.3 is greater than the inclination angle of the V-shaped inclined surface of the inner slide rail 1.2.

[0065] The upper and lower halves of the sliding connection assembly 5 have the same structure but a 90° phase difference. Both the upper and lower halves of the sliding connection assembly 5 have the following structures: grooved component limiting devices 5.4 are provided on both sides to cooperate with the base limiting device 1.1 of the base assembly 1 to prevent the support from being pulled out; outer friction pairs 5.3 of the sliding connection assembly are provided on both sides to slide on the base limiting device 1.1 of the base assembly 1; inner slide rail friction pairs 5.1 and outer slide rail friction pairs 5.2 are arranged on the upper and lower sides of the middle sliding connection assembly 5 to slide on the inner slide rail 1.2 and outer slide rail 1.3 of the upper and lower base assemblies 1, respectively.

[0066] In this embodiment, the coefficient of sliding friction between the outer slide rail friction pair 5.2 and the outer slide rail 1.3 is μ. out The coefficient of sliding friction between the inner slide rail friction pair 5.1 and the inner slide rail 1.2 is μ. in μ out >μ in .

[0067] In this embodiment, a base fixing angle steel 2 is provided on the outside of the base assembly 1. Bolt holes 6 are provided on the base assembly 1 and the base fixing angle steel 2 so that the base assembly 1 can be bolted to the structure.

[0068] In this embodiment, each base assembly 1 is provided with a lateral limiting device 4 at both ends, and a lateral limiting rubber pad 3 is provided on the inner side of the lateral limiting device 4.

[0069] like Figure 6 As shown in this embodiment, the design method for the anti-overturning variable stiffness inclined friction seismic isolation bearing includes the following steps:

[0070] S1. First, according to the isolation requirements of the isolation structure, the design displacement D of the inner slide rail (1.2) of the isolation bearing is determined c-in and the maximum design displacement D max ;

[0071] S2. The friction coefficient μ of the inner slide rail 1.2 and the outer slide rail 1.3 is initially determined in , μ out , and the inclination angle θ of the inner slide rail 1.2 and the outer slide rail 1.3 is designed in , θ out , which needs to ensure that μ in < tan θ in , μ out < tan θ out to ensure the self-resetting performance of the bearing after the earthquake;

[0072] S3. The mechanical model of the bearing is established, and the stress of the inner slide rail and the outer slide rail under different displacement stages is analyzed as follows:

[0073] The starting force F of the sliding between the base assembly 1 and the sliding connection assembly 5 start as shown in equation (1):

[0074] F starr = W (sin θ in + μ in cos θ in ) (25)

[0075] The initial stiffness K in as shown in equation (2):

[0076]

[0077] In the formula, W is the vertical load; h in is the vertical distance from the centroid of the sliding connection assembly 5 to the sliding surface of the inner slide rail 1.2;

[0078] The restoring force f reset as shown in equation (3):

[0079] f reset = W (sin θ in - μ in cos θ in ) (27)

[0080] From equation (1), by reducing θ in and μ in , F start can be reduced, so that the structure can start sliding under a small earthquake, avoiding brittle response;

[0081] From equation (2), a low inclination angle θ inand low friction coefficient μ in Design to make the initial stiffness K in At a lower level, match the flexible isolation requirements under the frequent earthquake;

[0082] From equation (3), when unloading, the gravity along the slope component (Wsinθ in ) drives the slider back, while the low friction coefficient (μ in < tanθ in ) ensures that the restoring force is always greater than zero;

[0083] When the displacement value exceeds the critical value D c-in , the outer slide rail intervenes, and its equivalent stiffness K out Approximately:

[0084]

[0085] From equation (4), by increasing the outer slide rail 1.3 inclination and friction coefficient, a larger restoring force and secondary yield stiffness can be achieved, and the isolation layer displacement can be effectively controlled; higher θ out and μ out Make K out At a higher level, forming a significant secondary stiffness platform, inhibiting displacement growth under a major earthquake; At the same time, the inclination of the outer slide rail θ out Increased gravity component;

[0086] S4. Calculate the required slope length of each slide rail to ensure that no derailment or stress overrun occurs under the design displacement, and the slope length calculation formula is shown in equation (5) and equation (6);

[0087]

[0088] In the formula, L in is the required slope length of the inner slide rail, L out is the required slope length of the outer slide rail, D c-in is the inner design displacement; D max is the maximum design displacement, which is determined according to the specification or time history analysis structure under the rare earthquake displacement demand; △L safe is the safety capacity to prevent derailment;

[0089] S5. Use genetic algorithm to conduct parameterized analysis combined with maximum energy consumption objective function and constraint conditions and numerical simulation verification to realize the determination and optimization of the slope length; Specifically, the maximum energy consumption objective function is constructed as follows:

[0090] Energy dissipation capacity is measured by the area enclosed by the hysteresis curve, and the total energy dissipation E total is expressed as equation (7) - equation (9):

[0091] E total = E in + E out (31)

[0092] E in = 4μ in WD c-in (32)

[0093] E out = 4μ out W(D max -D c-in ) (33)

[0094] where the coefficient 4 represents the energy dissipation of a complete hysteresis cycle, E in represents the inner slide rail friction energy dissipation, E out represents the outer slide rail friction energy dissipation;

[0095] The constraint conditions include the following:

[0096] Slide rail self-resetting condition:

[0097] μ in < tan θ in ; μ out < tan θ out (34)

[0098] Contact stress safety limit:

[0099]

[0100] where A 滑块 is the contact area of the sliding connection assembly with the slide rail; f allow is the material allowable stress;

[0101] Slide rail length feasibility:

[0102] L in cos θ in + L out cos θ out ≥ D max + ΔL safe (36)

[0103] With the above structure, the working principle of the anti-overturning function variable rigidity inclined plane frictional isolation bearing of the application is as follows: in the initial state, the inner slide rail friction pair 5.1 is in direct contact with the inner slide rail 1.2, and the outer slide rail friction pair 5.2 is not in contact with the outer slide rail 1.3. When an earthquake occurs, the inner slide rail friction pair and the inner slide rail dissipate energy through friction, and when the sliding connection assembly 5 moves to a certain displacement, the outer slide rail friction pair contacts the inner slide rail and dissipates energy through friction, and effectively controls the displacement of the isolation layer; when the isolation bearing is locally tensioned or the bearing is pulled off due to the inertia of the upper structure, the sliding connection assembly limiting device 5.4 cooperates with the base vertical limiting device 1.1 to prevent the bearing from being pulled off.

[0104] The base slide rail is a V-shaped inclined plane with different inclinations on the inner and outer sides, and the starting force F start and the initial stiffness K in of the bearing can be relatively small, and the bearing can be completely self-resetting after an earthquake.

[0105] The inclined sliding surface structure of the slide rail helps to reduce the base shear of the structure during the operation of the bearing, and significantly reduces the story drift angle of the structure at the epicenter, and by designing different inclinations and friction coefficients of the inner and outer slide rails 1.2, 1.3, the contradiction between the isolation rate and the displacement of the isolation layer can be effectively balanced. In the small earthquake stage, the inner slide rail dominates, the low inclination reduces the gravity component, and the low friction coefficient reduces the hysteresis energy dissipation, so as to realize high isolation rate; in the large earthquake stage, the outer slide rail intervenes, the high inclination increases the geometric stiffness, and the high friction coefficient enhances the friction energy dissipation, so as to form a stiffness jump and actively inhibit the growth of the displacement of the isolation layer.

[0106] The bearing can provide high bearing capacity during normal use, and the inner low-inclination inclined plane also plays a transition role. By arranging multiple-inclination inclined planes, smooth conversion between the inclined planes is realized, the instantaneous impact of the sliding block passing through the discontinuous inclined plane is reduced, and it is ensured that the bearing will not produce excessive deformation or even damage.

[0107] The lengths of the inner and outer slide rail inclined planes can be optimized to the optimal solution through simulation of the type of isolation structure. After the design parameters of the isolation structure are determined according to the requirements, a mechanical model of the bearing is established, the stress conditions of the inner and outer slide rails in different displacement stages are analyzed, and the lengths of the slide rail inclined planes are preliminarily calculated. Then, an optimization algorithm (genetic algorithm, etc.) is used to perform parameterized analysis and numerical simulation verification in combination with an objective function (maximum energy dissipation, etc.) and constraint conditions (design displacement not exceeding the length of the inclined plane, stress exceeding limit, etc.), so as to scientifically determine and optimize the lengths of the inclined planes, and take into account the isolation performance and engineering economy.

[0108] The base limiting device 1.1 is fixed with the base through the bolt hole 6 and the bolt 7, so that the sliding connecting assembly 5 can slide along the predetermined track when sliding on the base slide rails 1.2 and 1.3, and the sliding connecting assembly limiting device 5.4 and the base limiting device 1.1 can cooperate to prevent the isolation bearing from being pulled off when the isolation bearing is locally pulled or the isolation bearing is pulled off due to the inertia of the upper structure.

[0109] The friction pair is made of polytetrafluoroethylene friction material, and can dissipate the seismic energy in the sliding friction process.

[0110] The whole bearing adopts an assembled structure, so that the damaged parts can be replaced and the function of the bearing can be recovered after the earthquake, and the maintenance cost of the bearing after the earthquake is reduced.

[0111] In order to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A design method for an anti-overturning variable stiffness inclined friction seismic isolation bearing, the anti-overturning variable stiffness inclined friction seismic isolation bearing comprising two orthogonally arranged base assemblies (1) providing bidirectional self-resetting function, a sliding connection assembly (5) is provided between the two base assemblies (1) to slide between the base assemblies (1), each base assembly (1) comprising a base limiting device (1.1) and a base provided with slide rails of different inclination angles, the bases of the slide rails of different inclination angles comprising an outer slide rail (1.3) and an inner slide rail (1.2), the inner slide rail (1.2) being disposed between the two outer slide rails (1.3), the outer slide rail (1.3) and the inner slide rail (1.2) being both V-shaped inclined surfaces and the V-shaped inclined surface inclination angle of the outer slide rail (1.3) being greater than the V-shaped inclined surface inclination angle of the inner slide rail (1.2); The upper half and lower half of the sliding connection assembly (5) have the same structure but a 90° phase difference. Both the upper and lower half of the sliding connection assembly (5) have the following structure: groove-shaped component limiting devices (5.4) are provided on both sides to cooperate with the base limiting device (1.1) of the base assembly (1) to prevent the support from being pulled out; outer friction pairs (5.3) of the sliding connection assembly are provided on both sides for sliding on the base limiting device (1.1) of the base assembly (1); inner slide rail friction pairs (5.1) and outer slide rail friction pairs (5.2) are arranged on both the upper and lower sides of the sliding connection assembly (5) for sliding on the inner slide rail (1.2) and outer slide rail (1.3) of the upper and lower base assemblies (1), respectively. The method includes the following steps: S1. First, based on the seismic isolation requirements of the seismic isolation structure, determine the design displacement of the inner slide rail (1.2) of the seismic isolation bearing. and maximum design displacement ; S2. Preliminary determination of the coefficient of friction between the inner slide rail (1.2) and the outer slide rail (1.3). , Then, the inclination angles of the inner slide rail (1.2) and the outer slide rail (1.3) are designed. , It is necessary to ensure , To ensure the self-resetting performance of the bearings after an earthquake; S3. Establish a mechanical model of the support and analyze the force conditions of the inner and outer slide rails at different displacement stages as follows: The starting force that causes sliding between the base assembly (1) and the sliding connection assembly (5) As shown in equation (1): initial stiffness As shown in equation (2): In the formula, For vertical loads; The vertical distance from the center of mass of the sliding connection component (5) to the sliding surface of the inner slide rail (1.2); Resilience As shown in equation (3): From equation (1), we know that by reducing and It can reduce This allows the structure to initiate sliding even under minor earthquakes, avoiding brittle response; From equation (2), we know that the low tilt angle and low coefficient of friction The design ensures initial stiffness It is at a relatively low level, matching the requirements for flexible seismic isolation under frequent earthquakes; From equation (3), we can see that when the inner slide rail is unloaded, the component of gravity along the inclined plane is... The drive slider returns to its original position, while maintaining a low coefficient of friction. Ensure that the resilience is always greater than zero; When the displacement value exceeds the design displacement of the inner slide rail (1.2) When the outer slide rail intervenes, its equivalent stiffness Approximately: The vertical distance from the center of mass of the sliding connection assembly (5) to the sliding surface of the outer slide rail (1.3); Equation (4) shows that by increasing the inclination angle and friction coefficient of the outer slide rail (1.3), a larger restoring force and secondary yield stiffness can be achieved, and the displacement of the isolation layer can be effectively controlled; a higher and Make At a relatively high level, a significant secondary stiffness plateau is formed, suppressing displacement growth under large earthquakes; simultaneously, the inclination angle of the outer sliding rail... The increase leads to an increase in the component of gravity. S4. Calculate the required slope length for each slide rail to ensure that derailment or stress exceedance does not occur under the design displacement. The formulas for calculating the slope length are shown in equations (5) and (6). In the formula, This is the required length of the inclined plane for the inner slide rail. This is the required length of the inclined plane for the outer slide rail. The design displacement of the inner slide rail (1.2); To determine the maximum design displacement, the maximum displacement requirement under rare earthquakes is determined based on the specifications or time history analysis of the structure. To ensure safety and prevent derailment; S5. Using a genetic algorithm, combined with the maximum energy consumption objective function and constraints, parametric analysis and numerical simulation verification are performed to determine and optimize the slope length; specifically, the maximum energy consumption objective function is constructed as follows: Energy dissipation capacity is measured by the area enclosed by the hysteresis curve, representing the total energy dissipation. Represented as equations (7)-(9): In the formula, the coefficient 4 represents the energy consumption of a complete hysteresis cycle. This indicates the energy dissipation due to friction on the inner slide rail. This indicates the energy dissipation due to friction on the outer slide rail; The constraints include the following: Slide rail self-reset conditions: ; Contact stress safety limits: In the formula, The contact area between the sliding connection component and the slide rail; The allowable stress of the material; Feasibility of slide rail length: 。 2. The design method for the anti-overturning variable stiffness inclined friction seismic isolation bearing according to claim 1, characterized in that, The coefficient of sliding friction between the outer slide rail friction pair (5.2) and the outer slide rail (1.3) is: The coefficient of sliding friction between the inner slide rail friction pair (5.1) and the inner slide rail (1.2) is . , .

3. The design method for the anti-overturning variable stiffness inclined friction seismic isolation bearing according to claim 1, characterized in that, The base assembly (1) is provided with a base fixing angle steel (2) on its outer side. The base assembly (1) and the base fixing angle steel (2) are provided with bolt holes (6) so that the base assembly (1) can be bolted (7) to the structure.

4. The design method for the anti-overturning variable stiffness inclined friction seismic isolation bearing according to claim 1, characterized in that, Each of the base assemblies (1) is provided with a lateral limiting device (4) at both ends, and a lateral limiting rubber pad (3) is provided on the inner side of the lateral limiting device (4).

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