A site-specific hierarchical collaborative bridge seismic mitigation system and performance verification method

Abstract

The application discloses a kind of partial site grading cooperative bridge seismic mitigation system and performance verification method, it is related to bridge engineering earthquake resistance disaster mitigation technical field, the system will seismic mitigation function module be divided into beam bottom seismic mitigation module and beam end seismic mitigation module, along bridge longitudinal partial site arrangement and cooperate work.The beam bottom module is composed of anti-seismic sliding high-damping rubber bearing and annular steel wire rope damper, provides sliding-shear-tension energy dissipation and limiting function;Beam end module is composed of three-stage spring buffer and composite shock-absorbing rubber device, provides graded stiffness elastic restraint and compression energy dissipation limiting function.Two modules are unified control variable with main girder displacement, meet the graded displacement coordination relationship, constitute multiple seismic mitigation defense line.The application also provides corresponding performance verification method, and the displacement coordination, stiffness ratio and energy dissipation distribution index of the system are verified by nonlinear time history analysis.The application realizes the function of multiple defense, orderly energy dissipation and post-earthquake rapid recovery.

Description

Technical Field

[0001] This invention belongs to the field of earthquake resistance and disaster reduction technology in bridge engineering, specifically relating to a multi-part, graded, and coordinated bridge seismic isolation and reduction system and its performance verification method. Background Technology

[0002] As a crucial component of highways, railways, and urban roads, bridge structures play an indispensable role in crossing obstacles such as rivers and canyons. Earthquake resistance and disaster mitigation are key factors in bridge design and construction, as the degree of damage to bridge structures during earthquakes directly impacts the safety of these lifeline projects and post-earthquake rescue efforts.

[0003] Currently, bridge structures both domestically and internationally mostly employ ductile seismic resistance systems or seismic isolation systems. Ductile seismic resistance systems rely on the plastic hinges of the piers for energy dissipation, often resulting in irreparable residual deformation after an earthquake, making it difficult for bridges to quickly return to traffic. Seismic isolation systems, using seismic isolation bearings as a single energy dissipation mechanism, often suffer from excessive beam displacement, leading to block shearing, bearing slippage, and even beam collapse. Existing seismic isolation and energy dissipation devices mostly employ single-stage or two-stage designs, generally exhibiting poor adaptability to earthquakes of varying intensities, a lack of collaborative working mechanisms between devices, reliance on experience in parameter design, and insufficient consideration of beam collapse prevention mechanisms under rare earthquakes. Therefore, bridge structures with a single energy dissipation mechanism are ill-equipped to cope with complex and variable seismic forces and cannot meet the current development requirements for resilient bridges. Summary of the Invention

[0004] The purpose of this invention is to provide a bridge seismic isolation and reduction system and a performance verification method that is part-based and graded and coordinated, so as to overcome the shortcomings of traditional single energy dissipation mechanism bridge structure with poor adaptability and weak coordination, and realize the functions of multi-level defense, orderly energy dissipation and rapid post-earthquake recovery.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A segmented and graded collaborative bridge seismic isolation system includes a main girder, continuous piers, and inter-pier sections. The system divides the seismic isolation and damping functional modules into two parts: the bottom seismic isolation and damping module and the end seismic isolation and damping module. These modules are arranged in different locations along the longitudinal direction of the bridge. The two modules work together to form a multi-layered seismic isolation and damping defense line with hierarchical and orderly progression. The bottom seismic isolation module is arranged between the top of the continuous pier and the main beam. The bottom seismic isolation module consists of a seismic sliding high-damping rubber bearing with a sliding-shear composite working mechanism and an annular steel wire rope damper with tension energy dissipation and limiting functions. The bottom seismic isolation module provides sliding seismic isolation function under minor earthquakes, shear hysteresis energy dissipation function under moderate earthquakes, and steel wire rope tension energy dissipation and limiting function under major earthquakes. The beam-end seismic isolation module is arranged between the pier and the beam end of the main beam. The beam-end seismic isolation module consists of a three-stage spring buffer with a graded variable stiffness working mechanism and a composite damping rubber device with compression energy dissipation and limiting functions. The beam-end seismic isolation module provides first-stage stiffness elastic constraint under minor earthquakes, switches to second-stage stiffness to participate in energy dissipation under moderate earthquakes, and switches to third-stage stiffness to provide compression energy dissipation and limiting functions under major earthquakes. The beam bottom vibration isolation module and the beam end vibration isolation module are controlled by a unified displacement variable u. l Establish a collaborative working mechanism to meet the following hierarchical coordination relationships regarding displacement: Target displacement of minor earthquake: u 11 ≤ Δ0; Target displacement in moderate earthquake: Δ0 < u 12 ≤ Δ0 + 1.5H; Target displacement for a major earthquake: Δ0 + 1.5H < u 13 ≤ Δ0 + 2.5H ≤ D; Among them, u l The displacement of the main beam, u l1 For the displacement of the main beam during a minor earthquake, u 12 For the displacement of the main beam during a moderate earthquake, u 13 Δ0 is the displacement of the main beam under a major earthquake, H is the total thickness of the rubber layer of the bottom vibration isolation module (4), and D is the maximum allowable displacement of the main beam.

[0006] Furthermore, during the evolution of the system from minor to major earthquakes, the beam bottom vibration isolation module sequentially activates the sliding isolation function, the shear energy dissipation function, and the wire rope tensioning energy dissipation and limiting function. The graded trigger displacements for the three functions are set to 0, Δ0, and Δ0+1.5H, respectively.

[0007] Furthermore, the beam end vibration reduction and isolation module has a first-level stiffness, a second-level stiffness, and a third-level stiffness. The starting displacements of the three levels of stiffness are set to 0, Δ0, and Δ0+1.5H, respectively. The ratio of the three levels of stiffness satisfies: k2 / k1∈[2.5,3.5], k3 / k1∈[6.0,8.0].

[0008] Furthermore, the system satisfies the following energy dissipation distribution relationship under various levels of seismic loading: under moderate earthquakes, the energy dissipation of the beam bottom isolation modules accounts for ≥60%; under severe earthquakes, the energy dissipation of the beam bottom isolation modules accounts for 70%-80%, of which the energy dissipation of the seismic sliding high-damping rubber bearings accounts for 40%-45%, the energy dissipation of the annular wire rope dampers accounts for 30%-35%, and the energy dissipation of the beam end isolation modules accounts for 20%-30%; the system's equivalent damping ratio ξ total ≥0.30.

[0009] Further, the system is applicable to continuous girder bridges or cable-stayed bridges. When the bridge has only one span unit, the girder end seismic reduction and isolation module is disposed on the abutment.

[0010] Further, the designed maximum allowable displacement D=Δ0+2.5H+δ, where δ is the compression amount of the composite damping rubber device at the girder end, and δ=0.1H is taken, so that the buffering function of the girder end seismic reduction and isolation module is activated before the displacement of the main girder approaches D.

[0011] Further, the parameters and trigger logic of the seismic-resistant sliding high-damping rubber bearing, the three-stage spring buffer, the annular steel wire rope damper and the composite damping rubber device are configured as follows: Under the action of a minor earthquake, the girder displacement u<Δ0, only the seismic-resistant sliding high-damping rubber bearing slides and the first-stage spring compresses; Under the action of a moderate earthquake, Δ0≤u≤Δ0+1.5H, the seismic-resistant sliding high-damping rubber bearing enters the first shear deformation and the second-stage spring compresses; Under the action of a major earthquake, Δ0+1.5H<u≤Δ0+2.5H, the seismic-resistant sliding high-damping rubber bearing enters the second shear deformation, the third-stage spring compresses and the annular steel wire rope damper is tensioned to dissipate energy; When u reaches the designed maximum allowable displacement D, the composite damping rubber device compresses to dissipate energy and provides a displacement limiting function.

[0012] Further, the value range of Δ0 is 50-150mm, and the value range of H is 150-400mm.

[0013] Further, by coordinately setting the elastic stiffness and activation displacement of the girder bottom seismic reduction and isolation module and the girder end seismic reduction and isolation module, the horizontal shear force distribution at the tops of the continuous piers and the span-separating piers is uniform under the action of an earthquake, and the piers remain elastic.

[0014] A computer-aided performance verification method for a position-specific and stage-coordinated bridge seismic reduction and isolation system, which is used to verify the performance of the above seismic reduction and isolation system under the action of an earthquake, includes the following steps: S1. Establish a three-dimensional finite element model of the bridge. The model includes refined mechanical models of the girder bottom seismic reduction and isolation module and the girder end seismic reduction and isolation module, wherein a nonlinear connection unit is used to simulate the sliding-shear hysteretic behavior of the seismic-resistant sliding high-damping rubber bearing, a cable unit is used to simulate the tensioning and energy dissipation behavior of the annular steel wire rope damper, a multi-segment linear spring unit is used to simulate the staged variable stiffness behavior of the three-stage spring buffer, and a gap-compression unit is used to simulate the compression and limiting behavior of the composite damping rubber device; S2. Select at least seven sets of ground motion records matching the characteristics of the design ground motion, perform nonlinear time-history analysis under the three levels of minor earthquake, moderate earthquake and major earthquake respectively, and extract the following verification indicator: the maximum displacement u of the main girder max, the displacement value of the main girder when each device is started, the bending moment and shear force ratio at the bottom of the continuous pier and the partition pier, and the energy consumption ratio of the vibration reduction and isolation module at the girder bottom and the vibration reduction and isolation module at the girder end; S3. Comparing the indicators extracted in S2 with the displacement grading coordination relationship, stiffness ratio and energy consumption distribution ratio, and judging whether each indicator meets the preset allowable deviation; S4. Output the verification conclusion: when all the indicators in step S3 meet the allowable deviation, the performance of the system is judged to be qualified; when any indicator does not meet the requirement, the deviation source is located and the correction direction is output.

[0015] The beneficial effects of the present invention are as follows: 1. According to the present invention, by arranging the vibration reduction and isolation system in a differentiated manner at different positions, a multi-defense-line mechanism in which the girder bottom module and the girder end module work in coordination is constructed. The system takes the main girder displacement as a unified control variable, and precisely sets the graded displacement coordination relationship under minor earthquake, moderate earthquake and major earthquake (minor earthquake u<Δ0, moderate earthquake Δ0≤u≤Δ0+1.5H, major earthquake Δ0+1.5H<u≤Δ0+2.5H), which ensures the graded and orderly progression from isolation, energy consumption to displacement limitation, and overcomes the defect of poor adaptability of the traditional system to earthquakes of different intensities.

[0016] 2. By setting the specific starting displacement and proportional range of the three-stage stiffness of the girder-end vibration reduction and isolation module (k2 / k1∈[2.5,3.5], k3 / k1∈[6.0,8.0]) and linking with the slip-shear trigger mechanism of the girder-bottom module, the present invention effectively coordinates the horizontal shear distribution of the continuous piers and the partition piers, so that all the piers basically remain elastic under the earthquake. At the same time, the clear energy consumption distribution ratio of the system under the major earthquake (the total proportion of the girder bottom is 70%-80%, the support accounts for 40%-45%, and the steel wire rope accounts for 30%-35%) ensures that the main structure is protected.

[0017] 3. The present invention provides a computer-aided performance verification method including refined modeling and multi-level index verification. Key indicators such as main girder displacement and energy consumption ratio are extracted through nonlinear time-history analysis, and are compared and verified with the displacement coordination relationship, stiffness ratio and energy consumption distribution ratio set in the claims, which can scientifically and quantitatively evaluate the system performance, locate the deviation and provide the correction direction, thus ensuring the safety and reliability of the design. Brief Description of the Drawings

[0018] Figure 1 is a schematic diagram of the elevation layout of the bridge in Embodiment 1 of the present invention; Figure 2 is a schematic diagram of the plane layout of the bridge in Embodiment 1 of the present invention; Figure 3 is a schematic diagram of the anti-seismic slip high-damping rubber bearing of the present invention; Figure 4 is a schematic elevation view of the annular steel wire rope damper of the present invention; Figure 5 This is a planar schematic diagram of the annular wire rope damper of the present invention; Figure 6 This is a schematic elevation view of the three-stage spring buffer of the present invention; Figure 7 This is a top view of the three-stage spring buffer of the present invention after removing the main beam and the first embedded steel plate; Figure 8 This is a schematic diagram of the first-stage spring extension assembly of the three-stage spring buffer of the present invention; Figure 9 This is a schematic diagram of the composite rubber buffer device of the present invention.

[0019] In the picture: 1. Main beam; 2. Continuous pier; 3. Split pier; 31. Pier top back wall; 4. Beam bottom seismic isolation module; 41. Seismic sliding high-damping rubber bearing; 411. Upper connecting plate; 412. High-damping rubber body assembly; 413. Sliding assembly; 4131. Upper sliding panel; 4132. Lower sliding panel; 414. Base assembly; 4141. Limiting steel plate; 415. First protective cover; 42. Annular wire rope damper; 421. Fixing device; 4211. Embedded steel plate; 4212. Ear plate; 4213. Pin shaft; 422. Wire rope assembly; 4221. Annular wire rope; 4 222. Wire rope fixing clamp; 423. Tensioning assembly; 4231. Tensioning wire rope; 4232. Limiting anchor plate; 5. Beam end vibration damping module; 51. Three-stage spring buffer; 511. First embedded steel plate; 512. Second embedded steel plate; 513. Three-stage spring assembly; 5131. First stage spring; 5132. Second stage spring; 5133. Third stage spring; 514. Guide sleeve assembly; 52. Composite vibration damping rubber device; 521. Fixing steel plate; 522. Energy dissipating rubber; 523. Buffer microporous rubber; 524. Second protective cover; 53. Natural rubber support. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "horizontal," "inner," "outer," and "one side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1

[0023] See Figures 1 to 9 This embodiment provides a bridge seismic isolation system with segmented and hierarchical coordination, including a main beam 1, a continuous pier 2 set in the joint and a sub-joint pier 3 set at the end of the joint, and each sub-joint pier 3 is provided with a protruding pier top back wall 31.

[0024] A beam bottom vibration isolation module 4 is provided between the top of the continuous pier 2 and the bottom of the main beam 1. The beam bottom vibration isolation module 4 includes a seismic sliding high damping rubber bearing 41 and an annular steel wire rope damper 42.

[0025] like Figure 3 As shown, the seismic-resistant sliding high-damping rubber bearing 41 includes an upper connecting plate 411, a high-damping rubber body assembly 412, a sliding assembly 413, a base assembly 414, and a first protective cover 415. The high-damping rubber body assembly 412 is fixed to the bottom surface of the main beam 1 via the upper connecting plate 411, and its lower part is connected to the sliding assembly 413. The sliding assembly 413 is divided into an upper sliding panel 4131 and a lower sliding panel 4132. The base assembly 414 is fixed to the top surface of the continuous pier 2 and has limiting steel plates 4141 on both sides. The lower sliding panel 4132 is located between the limiting steel plates 4141. The upper sliding panel 4131 can slide relative to the limiting steel plates 4141 on both sides, and the sliding gap is set to Δ0. The total thickness of the rubber layer of the high-damping rubber body assembly 412 is H. Based on the relationship between the shear displacement of the high-damping rubber and the thickness of the rubber layer, within the allowable shear strain range of [0, 2.5], its deformation is divided into two levels: the first deformation level corresponds to [0, 1.5H], and the second deformation level corresponds to [1.5H, 2.5H].

[0026] like Figure 4 and Figure 5 As shown, the annular wire rope damper 42 includes a fixing device 421, a wire rope assembly 422, and a tensioning assembly 423. Specifically, the fixing device 421 includes a pre-embedded steel plate 4211, an ear plate 4212, and a pin 4213; the wire rope assembly 422 includes an annular wire rope 4221 and two sets of wire rope fixing clamps 4222; and the tensioning assembly 423 includes a tensioning wire rope 4231 and a limiting anchor plate 4232. The embedded steel plate 4211 is fixed to the continuous pier 2 and / or the main beam 1. Ear plates 4212 are fixed to the embedded steel plate 4211. A ring-shaped wire rope 4221 is positioned between wire rope fixing clamps 4222. One end of the tension wire rope 4231 is fixed to the ear plate 4212, and the other end is connected to the wire rope fixing clamps 4222 via a limiting anchor plate 4232 to adjust the slack of the ring-shaped wire rope 4221. The effective diameter of the ring-shaped wire rope 4221 is d. eq , set d eq =H, the tensioning assembly gives the annular wire rope a slack section, and the tension displacement is set to Δ0+1.5H.

[0027] A beam end vibration damping module 5 is installed between the top of the pier 3 and the end of the main beam 1. This module includes a three-stage spring damper 51, a composite damping rubber device 52, and a natural rubber bearing 53. The three-stage spring damper 51 and the composite damping rubber device 52 are installed in the gap between the end of the main beam 1 and the pier top back wall 31, and the natural rubber bearing 53 is located between the top surface of the pier 3 and the bottom surface of the main beam 1.

[0028] like Figures 6 to 8 As shown, the three-stage spring buffer 51 includes a first embedded steel plate 511, a second embedded steel plate 512, a three-stage spring assembly 513, and a guide sleeve assembly 514. The three-stage spring assembly 513 is divided into a first-stage spring 5131, a second-stage spring 5132, and a third-stage spring 5133 according to different stiffnesses. Each stage spring assembly consists of 2-4 springs connected in parallel, and variable stiffness is achieved by using different elastic coefficients and the number of springs.

[0029] like Figure 9 As shown, the composite shock-absorbing rubber device 52 includes a fixed steel plate 521 arranged sequentially from the outside to the inside, an energy-dissipating rubber 522 and a buffer microporous rubber 523 stacked together, and its design compression is set to 0.1H. A second protective cover 524 is arranged around the outermost part of the device.

[0030] In this embodiment, the first-stage spring 5131 of the three-stage spring buffer is combined with the sliding module of the anti-seismic sliding high-damping rubber bearing 41 to form a first-stage vibration reduction and isolation system; the second-stage spring 5132 is combined with the first deformation level module of the bearing to form a second-stage vibration reduction and isolation system; and the third-stage spring 5133 is combined with the second deformation level module of the bearing and the annular steel wire rope damper to form a third-stage vibration reduction and isolation system.

[0031] This system takes the relative horizontal displacement u of the main girder 1 with respect to the continuous pier 2 and the partition pier 3 l as the control target, allowing the main girder to generate relative horizontal displacement within the range of [0, D].

[0032] Its hierarchical cooperative working process is as follows: Under the working condition of minor earthquake action, the relative displacement u of the main girder l1 <Δ0 and u l1 <D, the seismic slip high-damping rubber bearing 41 slips within the range of [0, Δ0], the continuous pier does not generate a limiting effect on the main girder, and at the same time, the first-stage stiffness module spring set of the three-stage spring buffer 51 undergoes elastic compression, so as to extend the natural vibration period of the structure and realize minor earthquake isolation.

[0033] Under the working condition of moderate earthquake action, the relative displacement u of the main girder l2 <D, and Δ0 < u l2 <Δ0+1.5H, the upper slip panel of the seismic slip high-damping rubber bearing 41 has touched the limiting steel plate 4141, the high-damping rubber body enters the first deformation level to generate shear deformation with a deformation range of [0, 1.5H], and absorbs seismic energy through hysteretic energy dissipation; at the same time, the second-stage stiffness module spring set of the three-stage spring buffer 51 is compressed to provide restoring force.

[0034] Under the working condition of major earthquake action, the relative displacement u of the main girder l3 <D, and Δ0+1.5H < u l3 <Δ0+2.5H, the seismic slip high-damping rubber bearing 41 enters the second deformation level, continues to generate shear deformation (in the range of [1.5H, 2.5H]) and perform hysteretic energy dissipation; the third-stage stiffness module spring set is compressed to provide restoring force; at this time, the slack section of the annular steel wire rope damper 42 is used up, the annular steel wire rope is tensioned, which is connected in parallel with the second deformation level of the bearing to perform hysteretic energy dissipation together.

[0035] When the displacement of the main girder exceeds Δ0+2.5H and approaches the design maximum value D, the composite shock-absorbing rubber device 52 at the girder end comes into contact with the main girder, and forms a final soft contact-hard limit anti-falling girder constraint through the buffering of the buffering microporous rubber layer and the compression energy dissipation of the energy-dissipating rubber layer; at the same time, the annular steel wire rope damper 42 at the continuous pier forms a tension limit at the girder bottom, and the devices at the two positions reach the limit state simultaneously, forming the last line of defense.

[0036] Through the above core parameter association and hierarchical working mechanism, this embodiment realizes the stiffness matching and uniform shear force distribution of the continuous piers and the partition piers, and ensures that each bridge pier basically remains elastic under seismic action.

[0037] Embodiment 2

[0038] This embodiment takes a river-crossing bridge on a main road in a city as the engineering background. The bridge span arrangement is a 45m+2×72m+45m prestressed concrete variable cross-section continuous box girder. The total length of the bridge is 234m. It is located in an 8-degree seismic zone with a basic design seismic acceleration of 0.30g and a site category of Class II.

[0039] This bridge consists of one span, with three continuous piers (2) and two abutments. The bottom vibration isolation module (4) is located between the top of the continuous pier (2) and the bottom surface of the main beam, while the end vibration isolation module (5) is located between the abutment back wall and the end of the main beam. The construction and operation mechanism of the bottom vibration isolation module (4) and the end vibration isolation module (5) are the same as in Example 1, and will not be repeated here.

[0040] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A segmented and graded collaborative bridge seismic isolation system, comprising a main beam (1), continuous piers (2), and segmented piers (3), characterized in that: The system divides the seismic isolation and damping functional modules into two parts: the bottom seismic isolation and damping module (4) and the end seismic isolation and damping module (5), which are arranged in different locations along the longitudinal direction of the bridge. The two modules work together to form a multi-layered seismic isolation and damping defense line with hierarchical and orderly progression. The bottom vibration isolation module (4) is arranged between the top of the continuous pier (2) and the main beam (1). The bottom vibration isolation module (4) consists of a high-damping rubber bearing (41) with a sliding-shear composite working mechanism and an annular wire rope damper (42) with tension energy dissipation and limiting functions. The bottom vibration isolation module (4) provides sliding vibration isolation function under small earthquakes, shear hysteresis energy dissipation function under moderate earthquakes, and wire rope tension energy dissipation and limiting function under large earthquakes. The beam end vibration reduction and isolation module (5) is arranged between the pier (3) and the beam end of the main beam (1). The beam end vibration reduction and isolation module (5) consists of a three-level spring buffer (51) with a graded variable stiffness working mechanism and a composite vibration damping rubber device (52) with compression energy dissipation and limiting functions. The beam end vibration reduction and isolation module (5) provides first-level stiffness elastic constraint under small earthquakes, switches to second-level stiffness to participate in energy dissipation under moderate earthquakes, and switches to third-level stiffness to provide compression energy dissipation and limiting functions under large earthquakes. The bottom vibration isolation module (4) and the end vibration isolation module (5) establish a collaborative working mechanism through a unified displacement control variable u, satisfying the following displacement hierarchical coordination relationship: Target displacement of minor earthquake: u 11 ≤ Δ0; Target displacement in moderate earthquake: Δ0 < u 12 ≤ Δ0 + 1.5H; Target displacement for a major earthquake: Δ0 + 1.5H < u 13 ≤ Δ0 + 2.5H ≤ D; Where u is the displacement of the main beam, u l1 For the displacement of the main beam during a minor earthquake, u 12 For the displacement of the main beam during a moderate earthquake, u 13 Δ0 is the displacement of the main beam under a major earthquake, Δ0 is the initial sliding gap of the bottom vibration isolation module (4), H is the total thickness of the rubber layer of the bottom vibration isolation module (4), and D is the maximum allowable displacement of the main beam.

2. The segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, During the evolution of the system from minor to major earthquakes, the beam bottom vibration isolation module (4) sequentially activates the sliding isolation function, the shear energy dissipation function, and the wire rope tensioning energy dissipation and limiting function. The graded trigger displacements of the three functions are set to 0, Δ0, and Δ0+1.5H, respectively.

3. The segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, The beam end vibration reduction and isolation module (5) has a first-level stiffness k1, a second-level stiffness k2 and a third-level stiffness k3. The starting displacements of the three levels of stiffness are set to 0, Δ0 and Δ0+1.5H respectively. The ratio of the three levels of stiffness satisfies: k2 / k1∈[2.5,3.5], k3 / k1∈[6.0,8.0].

4. The segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, The system satisfies the following energy dissipation distribution relationship under various levels of seismic action: Under moderate earthquake action, the energy dissipation ratio of the beam bottom isolation module (4) is ≥60%; Under major earthquake action, the energy dissipation ratio of the beam bottom isolation module (4) is 70%-80%, of which the energy dissipation ratio of the seismic sliding high-damping rubber bearing (41) is 40%-45%, the energy dissipation ratio of the annular steel wire rope damper (42) is 30%-35%, and the energy dissipation ratio of the beam end isolation module (5) is 20%-30%; The equivalent damping ratio ξ of the system total ≥0.

30.

5. The segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, The system is applicable to continuous beam bridges or cable-stayed bridges. When the bridge has only one span, the beam end vibration isolation module (5) is set on the bridge abutment.

6. The segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, The maximum allowable displacement of the main beam is D = Δ0 + 2.5H + δ, where δ is the compression of the composite damping rubber device at the beam end. We take δ = 0.1H so that the buffering function of the beam end damping and isolation module (5) is activated before the main beam displacement approaches D.

7. A segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, The parameters and triggering logic of the seismic sliding high-damping rubber bearing (41), the three-stage spring buffer (51), the annular steel wire rope damper (42), and the composite damping rubber device (52) are configured as follows: Under minor earthquakes, the main beam displacement u < Δ0, only the seismic sliding high-damping rubber bearing (41) slides and the first-stage spring (5131) is compressed; Under the action of a moderate earthquake, Δ0≤u≤Δ0+1.5H, the seismic slip high-damping rubber bearing (41) enters the first shear deformation and the second-stage spring (5132) compresses; Under the action of a major earthquake, Δ0+1.5H<u≤Δ0+2.5H, the seismic slip high-damping rubber bearing (41) enters the second shear deformation, the third-stage spring (5133) compresses and the annular steel wire rope damper (42) is tensioned to dissipate energy; When u reaches the design maximum allowable displacement D, the composite damping rubber device (52) compresses to dissipate energy and provides a limiting function.

8. A segmented and graded collaborative bridge seismic isolation system according to any one of claims 1 to 7, characterized in that, The value range of Δ0 is 50-150mm, and the value range of H is 150-400mm.

9. A segmented and graded collaborative bridge seismic isolation system according to claim 1, characterized in that, By coordinately setting the elastic stiffness and activation displacement of the beam bottom seismic isolation module (4) and the beam end seismic isolation module (5), the horizontal shear force distribution at the top of the continuous pier (2) and the partition pier (3) is uniform under earthquake action, and the pier columns remain elastic.

10. A performance verification method for a segmented and graded collaborative bridge seismic isolation system, used to verify the performance of the system described in any one of claims 1-9 under seismic loading, characterized in that, Includes the following steps: S1. Establish a three-dimensional finite element model of the bridge, the model includes the refined mechanical models of the beam bottom seismic isolation module (4) and the beam end seismic isolation module (5), wherein the slip-shear hysteretic behavior of the seismic slip high-damping rubber bearing (41) is simulated by a nonlinear connection element, the tensioning energy dissipation behavior of the annular steel wire rope damper (42) is simulated by a cable element, the stepwise variable stiffness behavior of the three-stage spring buffer (51) is simulated by a multi-segment linear spring element, and the compression limiting behavior of the composite damping rubber device (52) is simulated by a gap-compression element; S2. Select at least seven sets of ground motion records that match the design ground motion characteristics, and perform nonlinear time history analysis under three levels: minor, moderate, and major earthquakes. Extract the following verification index: maximum displacement u of the main beam. max The main beam displacement value when each device is started, the bending moment and shear force ratio of the bottom of the continuous pier and the split pier, and the energy consumption ratio of the bottom vibration isolation module (4) and the end vibration isolation module (5). S3. Compare the indexes extracted in S2 with the displacement grading coordination relationship, stiffness ratio and energy dissipation distribution ratio, and judge whether each index meets the preset allowable deviation; S4. Output the verification conclusion: when all the indexes in step S3 meet the allowable deviation, the system performance is determined to be qualified; when any index does not meet the requirement, locate the deviation source and output the correction direction.

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