Combined type support gasket with adjustable friction coefficient and seismic mitigation and isolation support

Abstract

The invention relates to the technical field of bridge supports and seismic resistance, in particular to a composite support gasket with an adjustable friction coefficient and a seismic reduction and isolation support. Comprising a tetrafluoroethylene gasket body, a steel cover body is arranged outside the tetrafluoroethylene gasket body, the steel cover body comprises a first cover face, the first cover face is provided with a hollowed-out area, and tetrafluoroethylene materials exposed in the hollowed-out area and the first cover face jointly form a composite friction interface; and the area S1 of the hollow area accounts for 0%-100% of the surface area of the tetrafluoroethylene gasket body. The surface of an original tetrafluoroethylene gasket body is covered with steel surfaces with different areas, the steel surfaces and the tetrafluoroethylene gasket body jointly form a composite gasket interface, friction coefficients of the surface of the composite support gasket are different according to different coverage degrees, and therefore friction coefficient adjustment is achieved, and the service life of the composite support gasket is prolonged. And therefore, the design of the bridge support with different damping requirements can be adapted. The wear resistance of the support is greatly improved, and the anti-seismic safety of a bridge structure is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of bridge bearings and seismic resistance technology, and in particular to a composite bearing gasket with adjustable friction coefficient and a seismic isolation bearing. Background Art

[0002] Bridges are crucial nodes in transportation systems and are also vulnerable structures to earthquakes. They often play a critical role in controlling the seismic safety of transportation networks. Therefore, improving the seismic performance of bridge structures plays a crucial role in enhancing the seismic resilience of transportation networks. Numerous practical applications have demonstrated that appropriate seismic mitigation and isolation designs are effective methods for improving bridge seismic performance. By implementing appropriate seismic mitigation and isolation measures at pier-beam junctions and allowing for a certain relative displacement, the inertial forces transmitted to the substructure can be significantly reduced, achieving an optimal balance between the structural seismic internal forces and displacement responses.

[0003] The friction pendulum isolation bearing is a widely used isolation bearing with excellent performance. It mainly uses the friction of the bearing to form a considerable energy dissipation effect, increase the damping of the structure, and reduce the seismic response of the structure. In order to ensure the mobility of the steel bearing under normal operating conditions, reduce the friction of the bearing, and evenly transmit the pressure between the upper and lower connecting plates of the bearing, a bearing gasket must be installed between the bearing connecting plates. At present, the material of the bearing gasket is mostly tetrafluoroethylene, and the friction coefficient with the stainless steel surface is generally 0.04 to 0.08. When lubricated with silicone grease, the friction coefficient can be lower than 0.01, and the wear resistance of the bearing gasket can be significantly improved.

[0004] However, the working principle of friction pendulum isolation bearings is to increase the structural energy dissipation during earthquakes through the friction of the bearing, thereby increasing the structure's damping ratio and reducing its seismic response. Therefore, an excessively low friction coefficient is detrimental to the bearing's damping effectiveness. The current standard, JT T852-2013, for "Friction Pendulum Isolation Bearings for Highway Bridges," recommends a dynamic friction coefficient of 0.05 for isolation bearings, while the standard, JT / T 927-2014, for "Hyperbolic Spherical Isolation Bearings for Bridges," recommends a design sliding friction coefficient of 0.02 to 0.05. However, the friction coefficient between tetrafluoroethylene and stainless steel surfaces is generally 0.04 to 0.08 in a non-lubricated state and below 0.01 when lubricated. This makes it impossible to achieve a arbitrarily adjustable friction coefficient to meet the varying damping requirements of different structures. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a composite bearing gasket and a seismic isolation bearing with an adjustable friction coefficient.

[0006] The present invention provides a composite support gasket with an adjustable friction coefficient, comprising a tetrafluoroethylene gasket body, wherein a steel cover is arranged on the outside of the tetrafluoroethylene gasket body, wherein the steel cover includes a first cover surface, wherein the first cover surface has a hollow area, and the tetrafluoroethylene exposed in the hollow area and the first cover surface together constitute a composite gasket interface; the area S1 of the hollow area accounts for 0%-100% of the surface area of ​​the tetrafluoroethylene gasket body.

[0007] The technical solution of the present invention proposes a composite bearing gasket. In order to overcome the technical defect that the friction coefficient between the traditional seismic isolation bearing gasket material and the stainless steel surface layer cannot be adjusted, the invention proposes an inventive concept of a composite bearing gasket. By covering the surface of the original tetrafluoroethylene gasket body with steel surfaces of different areas, a composite gasket surface is formed together with the remaining tetrafluoroethylene gasket body, and the friction coefficient of the composite bearing gasket surface is different according to the degree of coverage, thereby achieving an adjustable friction coefficient, and thus being able to adapt to the design of bridge bearings with different shock absorption requirements. The wear resistance of the bearing is greatly improved, and the controllability and reliability of the mechanical properties of the friction-type seismic isolation bearing are significantly improved, thereby improving the seismic safety of the bridge structure.

[0008] Under the action of pressure, the friction interface of the composite support gasket includes both the contact surface between the stainless steel surface layer of the support plate and the tetrafluoroethylene, and the contact surface between the stainless steel surface layer of the support plate and the steel cover. Under lubrication conditions, the friction coefficient between the tetrafluoroethylene and the stainless steel surface layer is approximately 0.01, and the friction coefficient between the steel cover and the stainless steel surface layer is approximately 0.1.

[0009] Preferably, the steel surface of the first cover surface and the surface of the tetrafluoroethylene gasket body located in the hollow area together form a composite gasket surface, and the surface height of the composite gasket surface is consistent.

[0010] In order to achieve better adjustment of the friction coefficient of the composite support gasket, the height of the exposed surface of the tetrafluoroethylene gasket is consistent with the height of the steel surface of the first cover surface.

[0011] Preferably, the steel cover body includes a steel side wall, the steel side wall is arranged around the side wall of the tetrafluoroethylene gasket body, and the first cover surface and the steel side wall are designed as an integral whole.

[0012] In order to better combine the steel surface with the surface of the tetrafluoroethylene gasket body, the present invention designs the steel part into a cover body, which is similar to the structure of a bottle cap. The cover body has a cavity inside for accommodating the tetrafluoroethylene gasket body. The tetrafluoroethylene gasket body is filled into the steel cover body. At the same time, the cover surface is designed as a partially hollow structure, so that the surface of the tetrafluoroethylene gasket body can be exposed, and together with the solid steel cover surface part, a smooth composite surface is formed, thereby achieving the purpose of adjusting the surface friction coefficient.

[0013] The ratio of the area S1 of the hollow region to the surface area of ​​the tetrafluoroethylene gasket body includes any one of 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 99%.

[0014] By adding steel covers with different hollowed-out areas to the original PTFE gasket, composite bearing gaskets with low, medium, and high friction coefficients can be obtained. The composite bearing gasket operates in a lubricated state, which improves the wear resistance of the PTFE gasket and extends its service life.

[0015] Preferably, the composite support gasket is prepared according to the following method:

[0016] Step 1: first determine the friction coefficient of the composite support gasket, and determine the area ratio Y of the hollow area on the surface of the tetrafluoroethylene gasket body according to the friction coefficient;

[0017] Step 2: Prepare the steel cover according to the size of Y;

[0018] Step 3: Place the steel cover in a mold, and inject tetrafluoroethylene into the cavity of the steel cover to obtain a composite support gasket after molding.

[0019] When a steel cover with a larger hollow area is used, a composite support gasket with a relatively low friction coefficient can be obtained; when a steel cover with a medium hollow area is used, a composite support gasket with a medium friction coefficient can be obtained; when the steel cover has no hollow area, a composite support gasket with the highest friction coefficient can be obtained.

[0020] In a second aspect, the present invention provides a seismic isolation bearing, which includes an upper bearing plate, a lower bearing plate and a middle bearing plate located therebetween, a first contact surface being provided between the upper bearing plate and the middle bearing plate, a second contact surface being provided between the lower bearing plate and the middle bearing plate, a plurality of composite bearing gaskets being provided on the first contact surface, a plurality of composite bearing gaskets being provided on the second contact surface, and one side of the composite friction interface being provided close to the upper bearing plate or the lower bearing plate.

[0021] The present invention transforms the original single pressure-bearing friction surface of tetrafluoroethylene and the stainless steel surface layer of the support plate into a composite support gasket with multiple friction coefficient interfaces. The friction coefficient of the composite support gasket can be adjusted by adjusting the size of the hollow area of ​​the steel cover.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The technical solution of the present invention utilizes steel covers with varying hollowed-out areas on the outer cover of the original Teflon gasket to create composite bearing gaskets with varying friction coefficients. The composite bearing gasket operates in a lubricated state, improving the wear resistance of the Teflon gasket and extending its service life, thereby increasing the service life of the seismic isolation bearing. By adjusting the number of gaskets with different friction coefficients, the seismic isolation bearing can achieve flexible adjustment of the friction coefficient over a wide range of 0.01 to 0.10. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the top view of the composite bearing gasket with adjustable friction coefficient.

[0025] Figure 2 AA cross-sectional view of the composite bearing gasket with adjustable friction coefficient.

[0026] Figure 3 BB cross-sectional view of the composite bearing gasket with adjustable friction coefficient.

[0027] Figure 4 Schematic diagram of the composite support gasket with adjustable friction coefficient of Example 1.

[0028] Figure 5 Schematic diagram of the composite support gasket with adjustable friction coefficient of Example 2.

[0029] Figure 6 Schematic diagram of the composite support gasket with adjustable friction coefficient of Example 3.

[0030] Figure 7 This is a schematic structural diagram of the bridge support of Example 4.

[0031] Figure 8 This is a schematic top view of the bridge support of Example 4.

[0032] Markings in the figure: 1-PTFE gasket body, 2-steel cover, 3-composite support gasket, 4-upper support plate, 5-lower support plate, 6-middle support plate, 7-stainless steel surface layer. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0034] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or positional relationship, such as "upper", "lower", "left", "right", "center", "inside", and "outside", are based on the expressions of the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationship are merely for the purpose of facilitating the description of the scheme of the present invention or simplifying the description of the specific embodiments to facilitate the rapid understanding of the scheme by technicians, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship, and therefore should not be understood as limiting the present invention.

[0035] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simply understood that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", and "parallel", and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0036] In addition, the expressions “first”, “second”, “third”, etc. in the terms are merely used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0037] In addition, in the description of the embodiments of the present invention, "several," "plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0038] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0039] This embodiment provides a composite support pad 3 with adjustable friction coefficient, such as Figure 1-3 As shown, it includes a tetrafluoroethylene gasket body 1, and a steel cover body 2 is provided on the outside of the tetrafluoroethylene gasket body 1. The steel cover body 2 includes a first cover surface, and the first cover surface has a hollow area. The hollow area is used to fill the surface of the tetrafluoroethylene gasket body 1, and the area S1 of the hollow area accounts for 0%-100% of the surface area S2 of the tetrafluoroethylene gasket body 1.

[0040] This range does not include the endpoints of 0% and 100%. Specifically, in this embodiment, the steel surface of the first cover and the surface of the Teflon gasket body 1 located in the hollowed-out area together form a composite gasket surface. To effectively adjust the friction coefficient of the composite support gasket 3, the height of the exposed Teflon gasket surface is consistent with the height of the steel surface of the first cover. The thickness of the steel cover from the inner wall to the outer wall ranges from 0.1 to 1 mm. The material is carbon steel or alloy steel.

[0041] The steel cover 2 includes a steel sidewall that surrounds the sidewall of the PTFE gasket body 1. The first cover and the steel sidewall are integrally designed. To better integrate the steel surface with the surface of the PTFE gasket body 1, the steel portion is designed as a cover, similar to the structure of a bottle cap. The cover has a cavity inside to accommodate the PTFE gasket body 1. By filling the PTFE gasket body 1 within the steel cover 2 and designing the cover as a partially hollowed structure, the surface of the PTFE gasket body 1 can be exposed, and together with the solid steel cover portion, a smooth composite surface is formed, thereby achieving the purpose of adjusting the surface friction coefficient.

[0042] In this embodiment, the composite support washer 3 is preferably at least one of a circle, a square, a polygon, an ellipse, and a polygon with rounded corners. More specifically, the friction coefficient of the composite support washer 3 is adjustable in a range of 0.01-0.10.

[0043] Preferably, in this embodiment, the shape of the hollow area of ​​the composite support gasket 3 is not limited to the forms shown in the following embodiments 1-3. As long as the overall one-piece molding of the cover body can be ensured, the hollow area can be circular, square, or multiple fan-shaped.

[0044] This embodiment proposes an inventive concept for a composite bearing gasket 3. By covering the original Teflon gasket body 1 with steel surfaces of varying areas, the composite bearing gasket 3 and the remaining Teflon gasket body 1 together form a composite gasket surface. Depending on the degree of coverage, the friction coefficient of the composite bearing gasket 3 surface varies, thereby achieving an adjustable friction coefficient and adapting to the design of bridge bearings with different shock absorption requirements. This greatly improves the bearing's wear resistance, significantly enhances the controllability and reliability of the mechanical properties of the friction-type seismic isolation bearing, and thereby enhances the seismic safety of the bridge structure.

[0045] This embodiment provides a method for preparing a composite support gasket 3:

[0046] Step 1: first determine the friction coefficient of the composite support gasket 3, and determine the area ratio Y of the hollow area on the surface of the tetrafluoroethylene gasket body 1 according to the friction coefficient;

[0047] Step 2: Prepare the steel cover 2 according to the size of Y;

[0048] Step 3: Place the steel cover 2 in a mold, and inject tetrafluoroethylene into the cavity of the steel cover 2 to obtain a composite support gasket 3 after molding.

[0049] Example 1

[0050] This embodiment provides a composite support gasket 3, such as Figure 4 As shown, the area of ​​the designed hollow area is S1, the area of ​​the steel surface is S2, and the surface area of ​​the PTFE gasket body 1 is S3. S1+S2=S3; in this embodiment, S1 / S3=80%; S2 / S3=20%. The composite friction coefficient is 0.03.

[0051] Example 2

[0052] This embodiment provides a composite support gasket 3, such as Figure 5 As shown, the area of ​​the designed hollow area is S1, the area of ​​the steel surface is S2, and the surface area of ​​the PTFE gasket body 1 is S3. S1+S2=S3; in this embodiment, S1 / S3=60%; S2 / S3=40%. The composite friction coefficient is 0.05.

[0053] Example 3

[0054] This embodiment provides a composite support gasket 3, such as Figure 6As shown, the area of ​​the designed hollow area is S1, the area of ​​the steel surface is S2, and the surface area of ​​the PTFE gasket body 1 is S3. S1+S2=S3; in this embodiment, S1 / S3=20%; S2 / S3=80%. The composite friction coefficient is 0.08.

[0055] Example 4

[0056] This embodiment provides a shock-isolating support, such as Figure 7-8 As shown, the support structure includes an upper support plate 4 and a lower support plate 5, with a middle support plate 6 located between the upper and lower support plates 4 and 5. A first contact surface is defined between the upper and middle support plates 4 and 6, and a second contact surface is defined between the lower and middle support plates 5 and 6. Several composite support gaskets 3 are disposed between the first and second contact surfaces, wherein the composite surface of the composite support gaskets 3 faces the upper support plate 4 or the lower support plate 5. The multiple composite support gaskets 3 are arranged in a centrally symmetrical manner according to a design scheme employing a distributed gasket group. By adjusting the number of gaskets with different friction coefficients, flexible adjustment of the friction coefficient within a wide range of 0.01 to 0.10 can be achieved.

[0057] The technical solution of the present invention utilizes steel covers with varying hollowed-out areas on the outer cover of the original Teflon gasket to create composite bearing gaskets with varying friction coefficients. The composite bearing gasket operates in a lubricated state, improving the wear resistance of the Teflon gasket and extending its service life, thereby increasing the service life of the seismic isolation bearing. By adjusting the number of gaskets with different friction coefficients, the seismic isolation bearing can achieve flexible adjustment of the friction coefficient over a wide range of 0.01 to 0.10.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite bearing gasket with adjustable friction coefficient, comprising a tetrafluoroethylene gasket body (1), characterized in that: A steel cover (2) is provided on the outside of the tetrafluoroethylene gasket body (1), and the steel cover (2) includes a first cover surface, the first cover surface has a hollow area, and the exposed tetrafluoroethylene in the hollow area and the first cover surface together constitute a composite gasket interface; the area S1 of the hollow area accounts for 0%-100% of the surface area of ​​the tetrafluoroethylene gasket body (1).

2. The composite support gasket with adjustable friction coefficient according to claim 1, characterized in that: The steel surface of the first cover surface and the surface of the tetrafluoroethylene gasket body (1) located in the hollow area together form a composite gasket surface, and the surface height of the composite gasket surface is consistent.

3. The composite support gasket with adjustable friction coefficient according to claim 2, characterized in that: The steel cover body (2) comprises a steel side wall, and the steel side wall is arranged around the side wall of the tetrafluoroethylene gasket body (1), and the first cover surface and the steel side wall are designed as an integral whole.

4. The composite support gasket with adjustable friction coefficient according to claim 1, characterized in that: The ratio of the area S1 of the hollow region to the surface area of ​​the tetrafluoroethylene gasket body (1) includes 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 99%.

5. The composite bearing gasket with adjustable friction coefficient according to claim 1, characterized in that: The projection area of ​​the composite support gasket (3) is at least one of a circle, a square, a polygon, an ellipse, and a polygon with rounded corners.

6. The composite bearing gasket with adjustable friction coefficient according to claim 1, characterized in that: The material of the steel cover (2) is carbon steel or alloy steel.

7. The composite support gasket with adjustable friction coefficient according to claim 1, characterized in that: The thickness of the steel cover (2) is in the range of 0.1-1 mm.

8. The composite support gasket with adjustable friction coefficient according to claim 1, characterized in that: The adjustment range of the friction coefficient is 0.01-0.

10.

9. The composite bearing gasket with adjustable friction coefficient according to claim 1, characterized in that: The composite support gasket (3) is prepared according to the following method: Step 1: first determine the friction coefficient of the composite support gasket (3), and determine the area ratio Y of the hollow area on the surface of the tetrafluoroethylene gasket body (1) based on the friction coefficient; Step 2: Prepare the steel cover (2) according to the size of Y; Step 3: Place the steel cover (2) in a mold, and inject tetrafluoroethylene into the cavity of the steel cover (2), and obtain a composite support gasket (3) after molding.

10. A seismic isolation bearing, comprising an upper bearing plate (4), a middle bearing plate (6) and a lower bearing plate (5), characterized in that: It comprises a composite support gasket with adjustable friction coefficient as described in any one of claims 1 to 9, wherein the composite support gasket (3) is arranged between the middle support plate (6) and the upper support plate (4), and / or the composite support gasket (3) is arranged between the middle support plate (6) and the lower support plate (5).

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