A method for designing a shear pin parameter of a friction pendulum seismic isolation support

Abstract

The application discloses a kind of friction pendulum seismic isolation support shear pin parameter design method, it is related to bridge aseismatic design technical field, and the method includes: by finite element simulation calculation, the internal force response of shear direction of seismic isolation support shear pin under design earthquake action is determined;According to the internal force response of seismic isolation support shear pin under design earthquake action and the load proportion coefficient of the part of design earthquake exceeding frequent earthquake, the theoretical required shear strength of seismic isolation support shear pin under frequent earthquake action is determined;According to the theoretical required shear strength of seismic isolation support shear pin under frequent earthquake action, and the bearing friction, the actual required shear strength of seismic isolation support shear pin after considering bearing friction is determined.Solve the problem that shear strength of friction pendulum seismic isolation support shear pin is generally designed according to experience in prior art, shear strength design value of friction pendulum seismic isolation support shear pin is not accurate enough, and the problem that safety risk is caused by too large or too small shear strength.

Description

Technical Field

[0001] This invention relates to the field of bridge seismic design technology, specifically to a method for designing parameters of shear pins for friction pendulum seismic isolation bearings. Background Technology

[0002] In seismic design of bridges, seismic isolation bearings, as important energy-dissipating components, can alter the dynamic response characteristics of the structure through parameter design to reduce seismic input energy and lower seismic response. Friction pendulum seismic isolation bearings are widely used in the seismic design of long-span bridges due to their excellent seismic performance. Friction pendulum seismic isolation bearings primarily utilize the pendulum principle to achieve seismic isolation. During an earthquake, the shear pin of the friction pendulum seismic isolation bearing breaks, causing a certain displacement of the bearing. This displacement extends the structural period, thus achieving seismic isolation; simultaneously, the friction of the polymer material achieves energy dissipation through vibration reduction. After the earthquake, due to the pendulum principle, the bearing possesses partial self-resetting capability under gravity. Currently, the design philosophies for seismic isolation bearings differ between highway and railway bridge seismic codes. The highway bridge seismic code adopts a seismic design philosophy based on seismic isolation under seismic loading during E2 earthquakes, while the railway bridge seismic code adopts a seismic design philosophy based on seismic isolation under rare earthquake loading.

[0003] In existing technologies, the shear strength of friction pendulum seismic isolation bearings is usually designed based on experience. This results in the design value of the shear strength of the friction pendulum seismic isolation bearings being inaccurate, leading to problems such as excessive or insufficient shear strength, which may cause safety risks. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a design method for shear pin parameters of friction pendulum seismic isolation bearings. This method solves the problem that existing technologies typically design the shear strength of friction pendulum seismic isolation bearings based on experience, resulting in inaccurate design values ​​for the shear strength of the shear pins and leading to safety risks due to excessively high or low shear strength.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This solution provides a method for designing the parameters of the shear pin of a friction pendulum seismic isolation bearing, including:

[0007] The internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake was determined by finite element simulation calculation.

[0008] Based on the internal force response of the shear pin of the seismic isolation bearing under the design earthquake and the load proportion coefficient of the part of the design earthquake exceeding the frequent earthquake, the theoretical required shear strength of the shear pin of the seismic isolation bearing under the frequent earthquake is determined.

[0009] Based on the theoretical shear strength required of the seismic isolation bearing shear pin under common earthquake action and the bearing skin friction, the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing skin friction is determined.

[0010] In some alternative solutions, according to the formula: Q1=(0.5+β)×Q E Determine the theoretical shear strength required for the shear pins of the seismic isolation bearings under common earthquake conditions;

[0011] Where Q1 is the theoretically required shear strength of the seismic isolation bearing shear pin under frequent earthquake action, β is the load proportion coefficient of the design earthquake exceeding the frequent earthquake portion, and Q E This is to reduce the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake.

[0012] In some alternative schemes, when designing the shear pin parameters of the friction pendulum seismic isolation bearing for highway bridges, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is taken as 0.

[0013] In some optional schemes, when designing the shear pin parameters of the friction pendulum seismic isolation bearing for railway bridges, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is 0.25 when the basic seismic intensity of the bridge location is 7 degrees or below; 0.2 when the basic seismic intensity of the bridge location is 7.5 degrees; 0.15 when the basic seismic intensity of the bridge location is 8 degrees; and 0 when the basic seismic intensity of the bridge location is 8.5 degrees or above.

[0014] In some alternative schemes, according to the formula: Q2=Q1-μ S P determines the actual required shear strength;

[0015] Where Q2 is the actual required shear strength of the seismic isolation bearing shear pin after considering bearing skin friction, and Q1 is the theoretical required shear strength of the seismic isolation bearing shear pin under common earthquake action, μ S Let P be the horizontal static friction coefficient of the bearing, and P be the actual vertical bearing capacity of the seismic isolation bearing.

[0016] In some alternative schemes, after determining the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing friction, based on the theoretical required shear strength of the seismic isolation bearing shear pin under common earthquake action and the bearing friction, the required shear area of ​​the seismic isolation bearing shear pin in the shear direction is determined based on the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing friction and the shear limit strength of the material of the seismic isolation bearing shear pin.

[0017] In some alternative schemes, the required shear area of ​​the seismic isolation bearing shear pin in the shear direction is determined according to the formula: A=Q2 / τ;

[0018] Where A is the shear area required by the shear pin of the seismic isolation bearing in the shear direction, Q2 is the actual required shear strength of the shear pin of the seismic isolation bearing after considering the bearing friction, and τ is the ultimate shear strength of the material of the shear pin of the seismic isolation bearing.

[0019] In some alternative solutions, after determining the required shear area of ​​the seismic isolation bearing shear pin in the shear direction based on the actual required shear strength of the shear pin after considering the bearing friction and the ultimate shear strength of the shear pin material, the number of seismic isolation bearing shear pins required in the shear direction is determined according to the required shear area of ​​the seismic isolation bearing shear pin in the shear direction and the specifications of the seismic isolation bearing shear pin.

[0020] In some alternative schemes, according to the formula: n = 4A / πd 2 Determine the number of shear pins required for the seismic isolation bearings in the shear direction;

[0021] Where n is the number of shear pins required for seismic isolation bearings in the shear direction, A is the shear area required for the shear pins in the shear direction, and d is the diameter of the seismic isolation bearing.

[0022] In some alternative schemes, before determining the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake through finite element simulation calculation, the finite element simulation parameters are determined based on the bridge seismic resistance system and the installation position of the seismic isolation bearing.

[0023] Compared with existing technologies, the advantages of this invention are as follows: This solution determines the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake load through finite element simulation calculation; based on the internal force response of the shear pin under the design earthquake load and the load proportion coefficient of the portion of the design earthquake exceeding the frequent earthquake load, the theoretical required shear strength of the shear pin under the frequent earthquake load is determined; based on the theoretical required shear strength of the shear pin under the frequent earthquake load and the bearing friction resistance, the actual required shear strength of the shear pin after considering the bearing friction resistance is determined. This solves the problem that in existing technologies, the shear strength of the friction pendulum seismic isolation bearing shear pin is usually designed based on experience, resulting in inaccurate design values ​​for the shear strength of the friction pendulum seismic isolation bearing shear pin, leading to safety risks due to excessively high or low shear strength. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating the design method for the shear pin parameters of the friction pendulum seismic isolation bearing in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the present invention provides a method for designing the parameters of the shear pin of a friction pendulum seismic isolation bearing, comprising:

[0029] S0: Determine the finite element simulation parameters based on the bridge's seismic resistance system and the installation location of the seismic isolation bearings.

[0030] In this embodiment, a finite element model of the bridge is established, and after determining the finite element simulation parameters, finite element simulation analysis is performed.

[0031] S1: Determine the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake through finite element simulation calculation.

[0032] In this embodiment, finite element simulation is used to determine the internal force response in the shear direction under the design earthquake when the shear pin of the seismic isolation bearing is within the elastic range.

[0033] S2: Based on the internal force response of the shear pin of the seismic isolation bearing under the design earthquake and the load ratio coefficient of the part of the design earthquake exceeding the frequent earthquake, determine the theoretical required shear strength of the shear pin of the seismic isolation bearing under the frequent earthquake.

[0034] In some alternative embodiments, according to the formula: Q1=(0.5+β)×Q E Determine the theoretical shear strength required for the shear pins of the seismic isolation bearings under common earthquake conditions;

[0035] Where Q1 is the theoretically required shear strength of the seismic isolation bearing shear pin under frequent earthquake action, β is the load proportion coefficient of the design earthquake exceeding the frequent earthquake portion, and Q E This is to reduce the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake.

[0036] In this embodiment, by considering the load ratio factor of the portion of the design earthquake exceeding the frequent earthquake, and based on the internal force response of the shear pin of the seismic isolation bearing under the design earthquake, the theoretical required shear strength of the shear pin of the seismic isolation bearing under the frequent earthquake is determined.

[0037] Frequent earthquake action refers to probabilistic level earthquake action between frequent earthquakes and design earthquakes, with a return period between 100 and 475 years. Frequent earthquakes refer to earthquake action with a 40% probability of occurrence in 50 years, while design earthquakes refer to earthquake action with a 10% probability of occurrence in 50 years.

[0038] In some optional embodiments, when designing the shear pin parameters of the friction pendulum seismic isolation bearing for highway bridges, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is taken as 0.

[0039] In this embodiment, when designing the shear pin parameters of the friction pendulum seismic isolation bearing for the highway bridge, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is set to 0. This conforms to the seismic design concept of "two-level design" in the seismic design code for highway bridges.

[0040] In some optional embodiments, when designing the shear pin parameters of the friction pendulum seismic isolation bearing for railway bridges, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is 0.25 when the basic seismic intensity of the bridge location is 7 degrees or below; 0.2 when the basic seismic intensity of the bridge location is 7.5 degrees; 0.15 when the basic seismic intensity of the bridge location is 8 degrees; and 0 when the basic seismic intensity of the bridge location is 8.5 degrees or above.

[0041] In this embodiment, the relationship between the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake and the basic seismic intensity of the bridge is shown in Table 1. This conforms to the seismic design concept of "three-level design" in the seismic design code for railway bridges.

[0042] Table 1

[0043]

[0044]

[0045] S3: Based on the theoretical shear strength required by the shear pin of the seismic isolation bearing under common earthquake action and the bearing friction, determine the actual required shear strength of the shear pin of the seismic isolation bearing after considering the bearing friction.

[0046] In some alternative embodiments, according to the formula: Q2 = Q1 - μ S P determines the actual required shear strength;

[0047] Where Q2 is the actual required shear strength of the seismic isolation bearing shear pin after considering bearing skin friction, and Q1 is the theoretical required shear strength of the seismic isolation bearing shear pin under common earthquake action, μ S Let P be the horizontal static friction coefficient of the bearing, and P be the actual vertical bearing capacity of the seismic isolation bearing.

[0048] In this embodiment, based on the theoretically required shear strength of the seismic isolation bearing shear pin under common earthquake action, and after deducting the influence of bearing friction, the actual required shear strength of the seismic isolation bearing shear pin after considering bearing friction is determined.

[0049] S4: Based on the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing friction and the ultimate shear strength of the material of the seismic isolation bearing shear pin, determine the required shear area of ​​the seismic isolation bearing shear pin in the shear direction.

[0050] In some optional embodiments, the required shear area of ​​the seismic isolation bearing shear pin in the shear direction is determined according to the formula: A = Q2 / τ;

[0051] Where A is the shear area required by the shear pin of the seismic isolation bearing in the shear direction, Q2 is the actual required shear strength of the shear pin of the seismic isolation bearing after considering the bearing friction, and τ is the ultimate shear strength of the material of the shear pin of the seismic isolation bearing.

[0052] S5: Determine the number of seismic isolation bearing shear pins required in the shear direction based on the required shear area and specifications of the seismic isolation bearing shear pins.

[0053] In some alternative embodiments, according to the formula: n = 4A / πd 2 Determine the number of shear pins required for the seismic isolation bearings in the shear direction;

[0054] Where n is the number of shear pins required for seismic isolation bearings in the shear direction, A is the shear area required for the shear pins in the shear direction, and d is the diameter of the seismic isolation bearing.

[0055] In summary, this invention uses finite element simulation to determine the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake. Based on the internal force response of the shear pin under the design earthquake and the load proportion coefficient of the portion of the design earthquake exceeding the frequent earthquake, the theoretical required shear strength of the shear pin under the frequent earthquake is determined. Based on the theoretical required shear strength of the shear pin under the frequent earthquake and the bearing friction, the actual required shear strength of the shear pin considering the bearing friction is determined. This solves the problem in existing technologies where the shear strength of the friction pendulum seismic isolation bearing shear pin is usually designed based on experience, resulting in inaccurate design values ​​for the shear strength, leading to safety risks due to excessively high or low shear strength.

[0056] The following is a specific example to facilitate understanding of the present invention.

[0057] In a certain five-span continuous beam railway bridge, the basic intensity of the site is 7 degrees, the basic design acceleration value is 0.1g, and the peak ground acceleration zone is 0.12g.

[0058] Using finite element simulation, the internal force response Q in the shear direction of the seismic isolation bearing under the design seismic load was determined when the shear pin of the seismic isolation bearing was within the elastic range. E =1860kN, the actual vertical bearing capacity of the seismic isolation bearing P =6890kN, and the longitudinal reaction force of the seismic isolation bearing under static action R =600kN.

[0059] Table 1 shows that the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is 0.25. The theoretically required shear strength of the seismic isolation bearing shear pin under frequent earthquake loading is Q1=(0.5+β)×Q E =(0.5+0.25)×1860=1395kN.

[0060] The horizontal static friction coefficient μ of the finished bearing was determined according to the method in Appendix E of the "Enterprise Standard of China State Railway Group Co., Ltd. (Railway Bridge Bearings Part 2: Spherical Bearings)" (QC / R 756.2-2020). S =0.03. Considering the bearing friction, the actual required shear strength of the shear pin for the seismic isolation bearing is Q2 = Q1 - μ S P=1395-0.03×6890=1188.3kN.

[0061] When designing seismic isolation bearing shear pins, the static load requirements should also be met, i.e., Q2>R. If the actual required shear strength of the seismic isolation bearing shear pin is less than the reaction force in the longitudinal direction of the bridge under static load, then the actual required shear strength of the seismic isolation bearing shear pin should be taken as the magnitude of the reaction force in the longitudinal direction of the bridge under static load.

[0062] The shear pin material of the bridge seismic isolation bearing has an ultimate shear strength τ = 280 MPa. The required shear area of ​​the shear pin in the shear direction is...

[0063] The diameter of the seismic isolation bearing is 26mm. The required number of shear pins for the seismic isolation bearing in the shear direction is... indivual.

[0064] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly 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; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0065] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for designing parameters of shear pins for friction pendulum seismic isolation bearings, characterized in that, include: The internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake was determined by finite element simulation calculation. Based on the internal force response of the shear pin of the seismic isolation bearing under the design earthquake and the load proportion coefficient of the part of the design earthquake exceeding the frequent earthquake, the theoretical required shear strength of the shear pin of the seismic isolation bearing under the frequent earthquake is determined. Based on the theoretical shear strength required by the shear pin of the seismic isolation bearing under common earthquake action and the bearing friction, the actual required shear strength of the shear pin of the seismic isolation bearing after considering the bearing friction is determined. According to the formula: Q1=(0.5+β)×QE, the theoretical required shear strength of the seismic isolation bearing shear pin under frequent earthquake action is determined; Where Q1 is the theoretical shear strength required by the shear pin of the seismic isolation bearing under the action of a common earthquake, β is the load ratio coefficient of the part of the design earthquake exceeding the part of the common earthquake, and QE is the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the action of the design earthquake. When designing the shear pin parameters for friction pendulum seismic isolation bearings of railway bridges, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is 0.25 when the basic seismic intensity of the bridge location is 7 degrees or below; 0.2 when the basic seismic intensity of the bridge location is 7.5 degrees; 0.15 when the basic seismic intensity of the bridge location is 8 degrees; and 0 when the basic seismic intensity of the bridge location is 8.5 degrees or above. According to the formula: Q2=Q1 μSP determines the actual required shear strength; Where Q2 is the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing friction, Q1 is the theoretical required shear strength of the seismic isolation bearing shear pin under common earthquake action, μS is the horizontal static friction coefficient of the bearing, and P is the actual vertical bearing capacity of the seismic isolation bearing.

2. The method for designing parameters of the friction pendulum seismic isolation bearing shear pin as described in claim 1, characterized in that, When designing the shear pin parameters of the friction pendulum seismic isolation bearing for highway bridges, the load proportion factor for the portion of the design earthquake exceeding the frequent earthquake is taken as 0.

3. The method for designing parameters of the friction pendulum seismic isolation bearing shear pin as described in claim 1, characterized in that, Based on the theoretical shear strength required of the seismic isolation bearing shear pin under common earthquake action and the bearing friction, the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing friction is determined. Then, based on the actual required shear strength of the seismic isolation bearing shear pin after considering the bearing friction and the shear limit strength of the material of the seismic isolation bearing shear pin, the required shear area of ​​the seismic isolation bearing shear pin in the shear direction is determined.

4. The method for designing parameters of the friction pendulum seismic isolation bearing shear pin as described in claim 3, characterized in that, According to the formula: A=Q2 / τ, determine the shear area required for the shear pin of the seismic isolation bearing in the shear direction; Where A is the shear area required by the shear pin of the seismic isolation bearing in the shear direction, Q2 is the actual required shear strength of the shear pin of the seismic isolation bearing after considering the bearing friction, and τ is the ultimate shear strength of the material of the shear pin of the seismic isolation bearing.

5. The method for designing parameters of the friction pendulum seismic isolation bearing shear pin as described in claim 3, characterized in that, After determining the required shear area of ​​the seismic isolation bearing shear pin in the shear direction based on the actual required shear strength of the shear pin after considering the bearing friction and the ultimate shear strength of the shear pin material, the required number of seismic isolation bearing shear pins in the shear direction is determined according to the required shear area of ​​the seismic isolation bearing shear pin in the shear direction and the specifications of the seismic isolation bearing shear pin.

6. The method for designing parameters of the friction pendulum seismic isolation bearing shear pin as described in claim 1, characterized in that, Before determining the internal force response of the shear pin of the seismic isolation bearing in the shear direction under the design earthquake through finite element simulation calculation, the finite element simulation parameters are determined based on the bridge seismic resistance system and the installation position of the seismic isolation bearing.

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