Pipe bridge pier grading and limiting design method and device based on time history analysis method

Abstract

This invention relates to the field of pipeline crossing structure safety technology in oil and gas transportation and water conservancy distribution engineering, specifically to a graded limiting design method and device for pipeline bridge supports based on time history analysis. The design method includes disc spring selection and parameter design, initial setting of graded limiting structure parameters, time history analysis verification and parameter optimization, device assembly and construction, and graded limiting layout. The supporting device includes disc spring assemblies, disc spring bases, upper pressure plates, limiting supports, and other components. The disc spring assemblies are made of stacked alloy steel, and the limiting supports have a Z-shaped structure with stiffening ribs. Each component is precision-machined and wear-resistant, and is fixed to a PTFE sliding plate with high-strength bolts. A sleeve provides sealing protection. This invention features a refined design, convenient installation, precise limiting, high stability, and flexible adjustment of the gap and disc spring combination to adapt to different pipeline bridge working conditions. It can effectively limit the lateral over-limit displacement of the pipeline bridge, avoid disc spring eccentric instability, and ensure the structural safety of the pipeline bridge under loads such as earthquakes and water hammer.

Description

Technical Field

[0001] This invention relates to the field of pipeline crossing structure safety technology in oil and gas transportation and water conservancy distribution engineering, specifically to a graded limit design method and device for pipeline bridge piers based on time history analysis. Background Technology

[0002] In the oil, natural gas, and water conservancy transportation industries, long-distance pipelines often need to cross obstacles such as rivers, valleys, and roads. Pipeline bridges have become the mainstream construction method, and their systems consist of bridge superstructures, pipelines, piers, supports, and limiting components. As a key transitional connection between the pipeline and the bridge structure, pipeline piers bear the functions of transmitting the pipeline's own weight, medium loads, temperature stresses, internal pressure, and dynamic loads, while also constraining and coordinating the relative displacement between the pipeline and the bridge.

[0003] In actual operation, pipeline-bridge systems are not only affected by environmental factors such as wind loads and temperature changes, but also susceptible to dynamic loads such as earthquakes and water hammer. Earthquakes can cause overall vibration of the bridge and pipeline, generating large relative displacements and inertial forces; water hammer loads can cause rapid fluctuations in internal pipeline pressure, resulting in significant axial thrust and pipeline vibration response. Due to differences in dynamic characteristics such as mass, stiffness, and damping between pipelines and bridges, they form a coupled dynamic system connected by supports. Under dynamic loads, they will interact and amplify their responses, leading to damage or even destruction of supports, limiting components, and pipeline connection points.

[0004] In existing technologies, while the bridge-crossing pipeline support piers disclosed in patent CN117948482A have good shock absorption and seismic isolation performance and can absorb and dissipate water hammer and seismic impact energy, the use of multiple disc springs leads to a large amount of material consumption and high manufacturing costs. While the steel sliding support piers for pipelines within corridors disclosed in patent CN216041316U solve the problems of tight fit between the support and the pipeline and uniform height, improving seismic resistance, their installation process is cumbersome, requires high construction precision, and is not conducive to rapid on-site installation and adjustment, limiting their applicability in complex construction environments. Furthermore, existing pipeline bridge support pier limiting designs lack graded limiting design methods for lateral displacement, and the verification methods for structural response under dynamic loads are not refined enough, making it difficult to accurately match the deformation and stress requirements of different pipeline bridges. Therefore, the limiting effect and structural reliability need to be improved. Summary of the Invention

[0005] The purpose of this invention is to provide a graded limiting design method and device for pipeline bridge piers based on time history analysis, so as to realize graded limiting of pipeline bridge piers, reduce the interaction between pipelines and bridge structures, and improve the reliability and adaptability of the device under dynamic loads.

[0006] To achieve the above objectives, the technical solution of this application is: a graded limiting design method for pipeline bridge piers based on time history analysis, comprising: Determine the stiffness grade and corresponding size series of disc springs based on the deformation characteristics of the pipe bridge, select the specifications and type of disc springs in combination with the installation space, complete the strength check according to the number of load changes, obtain the number of parallel disc springs and the number of series groups, and obtain the overall performance parameters of the disc spring group. Set the initial value of the gap g between the limit bracket and the disc spring base, and determine the material, structural dimensions and connection and fixing parameters of each component of the graded limit device; The structural dynamic response of the pipe bridge under dynamic load is solved by time history analysis. Stress data of key components are extracted and strength is checked. If the design requirements are not met, the structural parameters are adjusted and the verification is repeated. Complete the sequential assembly, positioning, and fixing of each component of the graded limiting device according to the specifications to achieve the graded limiting layout of the pipe bridge piers.

[0007] In another implementation of the present invention, the strength verification method is as follows: when the number of load changes is less than or equal to the set value, the static strength is verified; when the number of load changes is greater than the set value, the fatigue strength is verified. Furthermore, the strength is verified by mechanical analysis or simulation methods in combination with material properties, disc spring size parameters and stress conditions of the pipe bridge. When space permits, large-diameter disc springs are preferred to reduce the number of disc spring assemblies.

[0008] In another implementation of the present invention, the overall performance parameters of the disc spring assembly are obtained as follows: load-bearing capacity , Free height Where n is the number of disc springs in parallel, i is the number of disc springs in series, P is the load-bearing capacity of a single disc spring, f is the deformation of a single disc spring, H is the free height of a single disc spring, and t is the thickness of a single disc spring.

[0009] In another implementation of the present invention, the specific implementation steps of the time history analysis method are as follows: Set the mechanical parameters of the materials of each component of the device, and initialize the initial displacement, velocity, and acceleration of the structure to zero. Select the time step and displacement and velocity control parameters, and obtain the integration constants required for time history analysis accordingly; Construct the mass matrix [M], damping matrix [C], and stiffness matrix [K] of the structure, solve for the equivalent stiffness matrix and equivalent load, and then obtain the structural displacement, velocity, and acceleration vectors; Extract stress data of key components of the device at each time point, compare them with the allowable stress of the corresponding materials, and evaluate the actual limiting effect of the device.

[0010] In another implementation of the present invention, the first two natural frequencies of the structure are calculated manually using an iterative method. , Combined with damping ratio The Rayleigh damping coefficient is obtained, and then the damping matrix [C] is obtained; the diagonal mass matrix [M] is formed by using the lumped mass method, and the stiffness matrix [K] is obtained by combining the bending stiffness of the beam element, the vertical stiffness of the disc spring group, the stress-strain relationship of the solid element and the contact stiffness estimation. The displacement vector is solved by using the Gaussian elimination method.

[0011] In another implementation of the present invention, structural parameters are adjusted, including one or more of the following: gap g, disc spring combination method, limit bracket size, stiffening rib welding spacing, and the gap g is ultimately determined by time history analysis.

[0012] In another implementation of the present invention, after the device is assembled, graded limiting is achieved, and when the pipe bridge undergoes lateral displacement... When the device's adapter bridge is designed to withstand lateral deformation under temperature changes, it will not trigger the limiting function; when At this time, the disc spring base contacts the limit bracket, and the limit bracket provides lateral reaction force. , To provide equivalent lateral stiffness, the lateral displacement of the pipe bridge is limited to the allowable range of the design.

[0013] This invention also provides a graded limiting device for pipeline bridge piers based on time history analysis, applied to the aforementioned graded limiting design method for pipeline bridge piers based on time history analysis, comprising: Disc spring assembly, stacked above disc spring base, is used to provide vertical elastic deformation capacity to absorb structural displacement; The sleeve, made of a resilient material, is fitted onto the outside of the disc spring assembly to achieve a sealed protection of the outer cavity of the disc spring assembly; The upper pressure plate covers the top of the disc spring assembly and contacts the sleeve, so that the disc spring assembly remains in a vertical and uniform compression state when it is compressed. The limiting bracket is symmetrically arranged around the disc spring base and has an adjustable gap g between it and the disc spring base to limit the horizontal movement of the disc spring base. Stiffening ribs are vertically welded to the web of the limiting bracket to enhance the local stability and overall bending stiffness of the limiting bracket.

[0014] In another embodiment of the present invention, the limiting bracket is a Z-shaped structure, mounted on the PTFE slide plate and fixedly connected by bolts and auxiliary components; the lower surface of the disc spring base is in sliding contact with the PTFE slide plate, and its edge is machined with a 45° chamfer with a chamfer radius of 2-5mm.

[0015] In another embodiment of the present invention, the disc spring assembly is composed of multiple disc springs made of alloy steel stacked in parallel, series or composite combination. When the thickness of the disc spring exceeds 3mm, a type B disc spring with a support surface is selected.

[0016] By adopting the above technical solution, the present invention can achieve the following technical effects: The design method of this invention takes time history analysis as its core, realizes refined design and parameter verification, can accurately solve the structural response under dynamic load, and optimizes parameters by stress verification. The selection of disc springs is quantitatively defined according to the number of load changes, and the hierarchical limit design logic takes into account both the normal deformation and over-limit constraints of the pipe bridge. The parameters can be flexibly adjusted according to the span and stress characteristics of the pipe bridge, and the design results are consistent with the actual working conditions.

[0017] The device of this invention is easy to install, requiring no complex procedures or special equipment, occupies little space, is suitable for complex installation environments, and is easy to modify existing systems. The device has precise positioning and high stability. The adjustable positioning bracket can avoid disc spring eccentric instability. The gap can be flexibly adapted to different pipe bridge deformation requirements. The multiple combination methods of the disc spring group further enhance its versatility. The vertical flexible support and the horizontal graded positioning work together to effectively ensure the safety of the pipe bridge structure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a cross-sectional view of the pipe support. Figure 2 A front view of a graded limiting device for pipeline bridge piers based on time history analysis. Figure 3 This is a side view of a graded limiting device for pipeline bridge supports based on time history analysis. Figure 4 This is a schematic diagram of a composite disc spring assembly. Figure 5 This is a schematic diagram of the limiting bracket structure; The numbers in the diagram are explained as follows: 1. Disc spring assembly; 2. Disc spring base; 3. Upper pressure plate; 4. Limit bracket; 5. Sleeve; 6. PTFE sliding plate; 7. Bolts and auxiliary components; 8. Stiffening ribs; 9. Pipes. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0023] Example 1 This embodiment provides a graded limit design method for pipeline bridge piers based on time history analysis, specifically including the following steps: S1. Disc Spring Selection and Parameter Design: Determine the stiffness grade of the disc spring based on the deformation characteristics of the tube bridge, and match the corresponding large stiffness, medium stiffness or small stiffness size series; select the outer diameter or inner diameter of the disc spring in combination with the installation space constraints. When space allows, choose a large diameter disc spring to reduce the number of combined plates. If the thickness of the disc spring exceeds 3mm, select a type B disc spring with a support surface to ensure uniform force distribution.

[0024] Strength verification is performed based on the number of load changes. For fewer load changes, static strength verification is used; for more load changes, fatigue strength verification is used. Furthermore, mechanical analysis or simulation methods are employed to verify the strength, taking into account material properties, disc spring dimensions, and the stress conditions of the pipe bridge. Based on the total bearing capacity and total deformation requirements of the pipe bridge, the number of parallel disc springs (n) and the number of series groups (i) are obtained. The overall performance parameters of the disc spring group are obtained through composite combination performance analysis, specifically: bearing capacity... Deformation amount Free height Where P is the load-bearing capacity of a single disc spring, f is the deformation of a single disc spring, H is the free height of a single disc spring, and t is the thickness of a single disc spring. By introducing correction coefficients for the number of series groups, the number of parallel pieces, and the thickness, the mechanical property attenuation of series combinations, the contact deformation effect of parallel combinations, and the compression allowance after stacking are considered respectively.

[0025] S2. Preliminary setting of graded limiting structure parameters: Set the initial value of the gap g between the limiting bracket and the disc spring base. This gap is the lateral gap reserved between the disc spring base and the limiting bracket, and is symmetrically arranged on the left, right and front and rear sides of the disc spring base; at the same time, determine the material, structural dimensions and connection and fixing parameters of each component of the graded limiting device, and clarify the processing and connection process requirements of each component.

[0026] S3. Time History Analysis Verification and Parameter Optimization: The structural dynamic response of the pipe bridge under dynamic loads such as earthquakes and water hammer is solved using the time history analysis method. The specific implementation steps are as follows: 3.1 Set the mechanical parameters of the materials of each component of the device, and initialize the initial displacement, velocity, and acceleration of the structure to zero. The Q235 steel has an elastic modulus of 206 GPa, a Poisson's ratio of 0.3, and a density of 7850 kg / m³. 3 60Si2Mn steel has an elastic modulus of 208 GPa, a Poisson's ratio of 0.3, and a density of 7850 kg / m³. 3 ; 3.2 Select the time step and displacement and velocity control parameters. In this embodiment, the time step Δt = 0.005s is selected, and the parameters β = 0.25 (controlling displacement accuracy) and γ = 0.5 (controlling velocity accuracy) are selected. Based on this, the integration constants required for time history analysis are obtained: , , , , , , ; 3.3 Construct the mass matrix [M], damping matrix [C], and stiffness matrix [K] of the structure, and manually calculate the first two natural frequencies of the structure using an iterative method. , The Rayleigh damping coefficient is obtained by combining the damping ratio ξ=0.05, and then the damping matrix is ​​obtained [C]. The lumped mass method is used to concentrate the mass of each component at the nodes to form a diagonal mass matrix [M]. The beam element is assembled after calculating the element stiffness matrix according to the bending stiffness formula. The disc spring group is included according to the vertical stiffness. The stiffness contribution of the solid element is derived through the stress-strain relationship. The contact stiffness is estimated based on the material hardness and contact area to obtain the stiffness matrix [K]. Then the equivalent stiffness matrix is ​​solved. With equivalent load The displacement vector is solved by Gaussian elimination, and then the structural velocity and acceleration vectors are obtained. 3.4 Extract stress data of key components such as disc spring assembly and limiting bracket at each moment, compare them with the allowable stress of the corresponding materials, and evaluate the actual limiting effect of the device. If the stress of key components exceeds the allowable stress or the limiting effect does not meet the design requirements, adjust the structural parameters and repeat the above verification steps. The structural parameters to be adjusted include one or more of the following: gap g, disc spring assembly method, limiting bracket size, and stiffening rib welding spacing. The gap g is finally determined by time history analysis. This gap can be flexibly adjusted according to the span, stress characteristics, and deformation requirements of the pipe bridge to adapt to the usage requirements under different working conditions.

[0027] S4. Assembly and Installation of the Device and the Graded Limiting Layout: Assemble, position, and fix each component of the graded limiting device according to specifications. After assembly, implement the graded limiting layout for the pipe bridge piers. The graded limiting logic is as follows: When the lateral displacement of the pipe bridge Δx ≤ g, the device adapts to the design allowable lateral deformation of the pipe bridge under temperature changes, does not trigger the limiting action, and is compatible with the minor lateral deformation under normal working conditions of the pipe bridge, avoiding unnecessary constraints on the normal deformation of the structure by the limiting device; when Δx > g, the disc spring base contacts the limiting bracket, and the limiting bracket provides lateral reaction force. ,in The lateral equivalent stiffness is used to limit the lateral displacement of the pipe bridge to exceed the design allowable range, thus preventing the structure from becoming unstable or damaged due to excessive displacement.

[0028] Example 2 This embodiment provides a graded limiting device for pipeline bridge piers based on time history analysis, applied to the graded limiting design method for pipeline bridge piers based on time history analysis described in Embodiment 1. The device includes: Disc spring assembly 1 is stacked on top of disc spring base 2, with the center of disc spring assembly 1 aligned with the center of disc spring base 2 to avoid uneven loading. Disc spring assembly 1 is composed of multiple disc springs made of 60Si2Mn high-quality alloy steel, stacked in parallel, series, or composite combinations. This material has excellent elastic properties, fatigue resistance, and load-bearing capacity, ensuring that disc spring assembly 1 can stably perform its buffering and reset functions under long-term repeated stress, extending the service life of the device. When the disc spring thickness exceeds 3mm, type B disc springs with support surfaces are selected to ensure the uniformity of force distribution in disc spring assembly 1. Disc spring assembly 1 is used to provide vertical elastic deformation capacity and absorb structural displacement caused by temperature, load, or creep shrinkage. In this embodiment, the disc spring dimensions are D×d×δ×H=120mm×60mm×5mm×30mm, stacked in a composite combination of 4 pieces in parallel and 2 sets in series, with a load-bearing capacity of... = Deformation amount 3 = 2 × 8 × Free height .

[0029] Sleeve 5, made of polyester material with good resilience and no air leakage, is sleeved on the outside of disc spring assembly 1. This material does not bear the force transmitted by the pipe bridge. The force on the pipe bridge is entirely borne by disc spring assembly 1. The selection of polyester material ensures the sealing of the cavity outside disc spring assembly 1 without adversely affecting the mechanical performance of the device, thus achieving sealed protection for disc spring assembly 1.

[0030] The upper pressure plate 3 covers the top of the disc spring assembly 1 and contacts the sleeve 5. The center of the upper pressure plate 3 is aligned with the center of the disc spring assembly 1 to ensure that the contact surfaces of the upper pressure plate 3 and the disc spring assembly 1 are fully in contact. The upper pressure plate 3 is the force-bearing component at the top of the disc spring. Its contact surface with the disc spring assembly 1 is precision machined to ensure the flatness and smoothness of the contact surface, reduce the friction when the disc spring is compressed, improve the elastic response speed of the disc spring assembly 1, and keep the disc spring assembly 1 in a vertical and uniform compression state during the compression process. This prevents the disc spring from being unbalanced or tilted, and ensures that the elastic performance of the disc spring assembly 1 is fully utilized.

[0031] The disc spring base 2 is made of Q235 steel, which has good mechanical and processing properties, ensuring the load-bearing capacity and durability of the base. The disc spring base 2 is placed stably on the designated position of the PTFE sliding plate 6, closely fitting the support surface without loosening or tilting. Its upper surface is closely fitted with the disc spring assembly 1, and its lower surface is in sliding contact with the PTFE sliding plate 6, reducing frictional resistance during relative sliding. At the same time, the disc spring base 2 can evenly transfer the reaction force borne by the disc spring assembly 1 to the PTFE sliding plate 6. Its structural design meets the strength and rigidity requirements, preventing deformation or damage during stress. The edges of the disc spring base 2 are machined with a 45° chamfer with a chamfer radius of 2-5mm to avoid sharp angles causing wear to surrounding components, and to facilitate the installation and disassembly of the device.

[0032] The limiting bracket 4 is made of Q235 steel, which has good mechanical properties, weldability, and processing performance, ensuring the foundation bearing strength and durability of the limiting bracket 4 and meeting the long-term working requirements of the pipe bridge limiting device. The limiting bracket 4 has a Z-shaped structure, integrally formed by the upper flange, web, and lower flange, and is symmetrically arranged on the left, right, front, and rear sides of the disc spring base 2, with an adjustable gap g reserved between it and the disc spring base 2. In this embodiment, the gap g is determined to be 11mm by time history analysis. The height of the limiting bracket 4 is 15mm, and the cross-sectional dimensions are 60mm×60mm×6mm. The limiting bracket 4 is installed on the PTFE sliding plate 6 and fixedly connected by bolts and auxiliary components 7. Its core function is to limit the horizontal movement of the disc spring base 2, preventing the disc spring assembly 1 from "lateral buckling" or "tilting compression" under eccentric force, and ensuring that the central axis of the entire limiting device remains stable. The contact surface between the limiting bracket 4 and the disc spring base 2 is treated with wear-resistant material to reduce wear during contact and extend the service life of the device.

[0033] Bolts and auxiliary components 7 are made of high-strength bolts of grade 8.8 or above, used in conjunction with auxiliary components such as anti-loosening washers. High-strength bolts have high tensile strength, yield strength and shear strength, which can provide reliable connection strength for the device, while achieving effective anti-loosening protection to prevent the bolts from loosening under vibration loads. In this embodiment, four high-strength bolts are used to fix each limiting bracket 4 to the PTFE sliding plate 6, and the bolt tightening torque is 180 N·m to ensure the firmness and reliability of the connection. Bolts and auxiliary components 7 are also used to connect the disc spring base 2 and the PTFE sliding plate 6, which have good connection strength and anti-loosening performance, ensuring the stability of the connection during long-term service of the device.

[0034] The stiffening ribs 8, made of Q235 steel, are vertically installed and welded to the web of the limiting bracket 4. They are connected to the upper and lower flanges of the limiting bracket 4 respectively. In this embodiment, the cross-sectional dimensions of the stiffening ribs 8 are 10mm × 8mm, and the welding spacing is 100mm. The stiffening ribs 8 are used to enhance the local stability and overall bending stiffness of the limiting bracket 4, effectively preventing web buckling, flange warping, or overall lateral bending when subjected to lateral impact loads. This ensures that the limiting bracket 4 maintains structural integrity and functional reliability during long-term service. The number, spacing, and cross-sectional dimensions of the stiffening ribs can be designed and adjusted according to the actual load size and structural requirements.

[0035] The core function of this device is to achieve the coordinated operation of vertical flexible support and lateral graded limiting. Under the action of live load, temperature load, etc., the disc spring group 1 undergoes vertical compression, which realizes the function of releasing structural constraint force, reducing the additional force of temperature expansion and contraction, and providing flexible support. The vertical direction is not affected by the limiting bracket 4. When the pipe bridge deviates in the transverse or longitudinal direction and the lateral displacement Δx>g, the disc spring base 2 contacts the limiting bracket 4. The limiting bracket 4 provides lateral reaction force to prevent the structure from continuing to displace excessively, ensuring the stress safety and stability of the pipe bridge structure under various working conditions such as temperature change, vehicle load, earthquake, and water hammer.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A graded limiting design method for pipeline bridge piers based on time history analysis, characterized in that, Includes the following steps: Determine the stiffness grade and corresponding size series of disc springs based on the deformation characteristics of the pipe bridge, select the specifications and type of disc springs in combination with the installation space, complete the strength check according to the number of load changes, obtain the number of parallel disc springs and the number of series groups, and obtain the overall performance parameters of the disc spring group. Set the initial value of the gap g between the limit bracket and the disc spring base, and determine the material, structural dimensions and connection and fixing parameters of each component of the graded limit device; The structural dynamic response of the pipe bridge under dynamic load is solved by time history analysis. Stress data of key components are extracted and strength is checked. If the design requirements are not met, the structural parameters are adjusted and the verification is repeated. Complete the sequential assembly, positioning, and fixing of each component of the graded limiting device according to the specifications to achieve the graded limiting layout of the pipe bridge piers.

2. The graded limiting design method for pipeline bridge piers based on time history analysis as described in claim 1, characterized in that, The strength verification method is as follows: when the number of load changes is less than or equal to the set value, the static strength verification is performed; when the number of load changes is greater than the set value, the fatigue strength verification is performed. Furthermore, the mechanical analysis or simulation method is used to verify the strength in combination with the material properties, disc spring size parameters and the stress condition of the pipe bridge. When space permits, large-diameter disc springs are preferred to reduce the number of disc spring assemblies.

3. The graded limiting design method for pipeline bridge piers based on time history analysis as described in claim 1, characterized in that, The overall performance parameters of the disc spring assembly are obtained as follows: load-bearing capacity. , Free height Where n is the number of disc springs in parallel, i is the number of disc springs in series, P is the load-bearing capacity of a single disc spring, f is the deformation of a single disc spring, H is the free height of a single disc spring, and t is the thickness of a single disc spring.

4. The graded limiting design method for pipeline bridge piers based on time history analysis as described in claim 1, characterized in that, The specific implementation steps of the time history analysis method are as follows: Set the mechanical parameters of the materials of each component of the device, and initialize the initial displacement, velocity, and acceleration of the structure to zero. Select the time step and displacement and velocity control parameters, and obtain the integration constants required for time history analysis accordingly; Construct the mass matrix [M], damping matrix [C], and stiffness matrix [K] of the structure, solve for the equivalent stiffness matrix and equivalent load, and then obtain the structural displacement, velocity, and acceleration vectors; Extract stress data of key components of the device at each time point, compare them with the allowable stress of the corresponding materials, and evaluate the actual limiting effect of the device.

5. The graded limiting design method for pipeline bridge piers based on time history analysis as described in claim 4, characterized in that, The first two natural frequencies of the structure were calculated manually using an iterative method. , Combined with damping ratio The Rayleigh damping coefficient is obtained, and then the damping matrix [C] is obtained; the diagonal mass matrix [M] is formed by using the lumped mass method, and the stiffness matrix [K] is obtained by combining the bending stiffness of the beam element, the vertical stiffness of the disc spring group, the stress-strain relationship of the solid element and the contact stiffness estimation. The displacement vector is solved by using the Gaussian elimination method.

6. The graded limiting design method for pipeline bridge piers based on time history analysis as described in claim 1, characterized in that, The structural parameters are adjusted, including one or more of the following: gap g, disc spring combination method, limit bracket size, and stiffening rib welding spacing, and the gap g is finally determined by time history analysis.

7. The graded limiting design method for pipeline bridge piers based on time history analysis as described in claim 1, characterized in that, After the device is assembled, it achieves graded limit switches, which are activated when the pipe bridge undergoes lateral displacement. When the device's adapter bridge is designed to withstand lateral deformation under temperature changes, it will not trigger the limiting function; when At this time, the disc spring base contacts the limit bracket, and the limit bracket provides lateral reaction force. , To provide equivalent lateral stiffness, the lateral displacement of the pipe bridge is limited to the allowable range of the design.

8. A graded limiting device for pipeline bridge piers based on time history analysis, applied to the graded limiting design method for pipeline bridge piers based on time history analysis as described in any one of claims 1-7, characterized in that, include: Disc spring assembly, stacked above disc spring base, is used to provide vertical elastic deformation capacity to absorb structural displacement; The sleeve, made of a resilient material, is fitted onto the outside of the disc spring assembly to achieve a sealed protection of the outer cavity of the disc spring assembly; The upper pressure plate covers the top of the disc spring assembly and contacts the sleeve, so that the disc spring assembly remains in a vertical and uniform compression state when it is compressed. The limiting bracket is symmetrically arranged around the disc spring base and has an adjustable gap g between it and the disc spring base to limit the horizontal movement of the disc spring base. Stiffening ribs are vertically welded to the web of the limiting bracket to enhance the local stability and overall bending stiffness of the limiting bracket.

9. The graded limiting device for pipeline bridge supports based on time history analysis as described in claim 8, characterized in that, The limiting bracket has a Z-shaped structure, is installed on the PTFE slide plate and is fixedly connected by bolts and auxiliary components; the lower surface of the disc spring base is in sliding contact with the PTFE slide plate, and its edge is machined with a 45° chamfer with a chamfer radius of 2-5mm.

10. The graded limiting device for pipeline bridge supports based on time history analysis as described in claim 8, characterized in that, The disc spring assembly is composed of multiple disc springs made of alloy steel stacked in parallel, series or composite combination. When the thickness of the disc spring exceeds 3mm, a type B disc spring with a support surface is selected.

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