A friction energy dissipator and a ductile bridge pier structure

Abstract

This invention provides a friction energy dissipator and a ductile bridge pier structure. The friction energy dissipator includes an outer cylinder, a push rod, a piston, a friction sleeve, and an elastic reset component. The piston, friction sleeve, and outer cylinder are coaxially arranged. The friction sleeve is fitted outside the piston, and the outer wall of the friction sleeve contacts the inner wall of the outer cylinder, allowing relative sliding between them. The push rod and the elastic reset component are movably disposed at both ends of the outer cylinder, and both ends of the piston bear the forces applied by the push rod and the elastic reset component, respectively, to achieve overall sliding of the piston and friction sleeve inside the outer cylinder. The ductile bridge pier structure, equipped with the aforementioned friction energy dissipator, includes a foundation, a pre-set damage section, and a pier section arranged sequentially along the height direction. The outer cylinder is embedded in the foundation, and the push rod is embedded in the pier section. This invention, by sequentially arranging an outer reinforcing cage, a friction energy dissipator, and an inner reinforcing cage from the outside to the inside of the bridge pier structure, enables layer-by-layer damage energy dissipation of the bridge pier structure from the outside to the inside.

Description

Technical Field

[0001] This invention relates to the field of high-speed railway bridge construction technology, specifically to a friction energy dissipator and a ductile bridge pier structure. Background Technology

[0002] During the construction of the high-speed railway network, the construction of high-speed railway bridges cannot completely avoid potential earthquake zones. A certain proportion of high-speed railway bridges are close to or even cross active faults, facing the severe test of near-fault earthquakes.

[0003] Near-fault earthquakes are earthquakes that occur close to the fault rupture surface, and are fundamentally different from conventional mid- to far-field earthquakes. They are characterized by large peak ground accelerations (PGA) in both horizontal and vertical motions, and long dominant periods. A significant proportion of near-fault earthquakes exhibit unidirectional velocity pulses parallel to the fault slip direction and bidirectional velocity pulses perpendicular to the fault strike, as well as effects on the hanging wall and footwall, slip-thrust, and rupture directionality.

[0004] In actual near-fault major and super-major earthquakes, railway bridges are unable to withstand the force, exposing many seismic deficiencies in their design. Currently, high-speed railway bridge piers are mostly designed as robust solid or hollow piers with large cross-sectional dimensions to ensure track smoothness and withstand the horizontal collision forces of high-speed trains. Under normal operating conditions, the concrete piers alone provide sufficient strength and stiffness. Therefore, the reinforcement ratio of the piers is very small, typically with only a ring of longitudinal reinforcement near the outer edge of the cross-section. Under near-fault major and super-major earthquakes, the connection between the pier and the abutment is prone to failure; excessive stress at the outer longitudinal reinforcement at the bottom of the pier can easily lead to fracture; and the core concrete of the pier, without the restraint of steel reinforcement, is prone to brittle fracture, overall tilting, or collapse. While using high-performance composite materials and SMA to improve the seismic performance of piers is difficult to construct and expensive in actual engineering, it is difficult to meet the characteristics of large size and large number of railway bridge piers.

[0005] In summary, there is an urgent need for a friction energy dissipator and a ductile bridge pier structure to solve the problems existing in the current technology. Summary of the Invention

[0006] The purpose of this invention is to provide a friction energy dissipator and a ductile bridge pier structure to solve the problem that bridge pier structures are easily damaged under near-fault earthquakes.

[0007] To achieve the above objectives, the present invention provides a friction energy dissipator, comprising an outer cylinder, a push rod, a piston, a friction sleeve, and an elastic reset member; the piston, friction sleeve, and outer cylinder are coaxially arranged; the friction sleeve is sleeved outside the piston, and the outer wall of the friction sleeve contacts the inner wall of the outer cylinder, allowing relative sliding between them; the push rod and the elastic reset member are respectively movably disposed at both ends of the outer cylinder, and both ends of the piston bear the force applied by the push rod and the elastic reset member, thereby realizing the overall sliding of the piston and the friction sleeve inside the outer cylinder.

[0008] Preferably, a friction energy dissipator further includes a rotary reset assembly movably disposed between the push rod and the piston, wherein the two ends of the rotary reset assembly are in contact with the push rod and the piston, respectively.

[0009] Preferably, the rotary reset assembly includes a rotary block, and the outer peripheral surface of the rotary block is provided with a plurality of guide strips, the length direction of the guide strips being parallel to the axial direction of the outer cylinder;

[0010] The inner wall of the outer cylinder is provided with a guide portion for cooperating with the guide bar, and the guide portion includes a plurality of guide slopes for contacting one end of the guide bar;

[0011] One end of the push rod is provided with a serrated structure for contacting one end of the guide bar, and the end slope of the serrated structure is parallel or coplanar with the guide slope.

[0012] One end of the guide strip is provided with a contact slope for engaging with the guide slope or end slope.

[0013] Preferably, the guide portion further includes a guide groove connected between two adjacent guide ramps, the guide groove matching the guide strip.

[0014] The present invention also provides a ductile bridge pier structure, which is equipped with the above-mentioned friction energy dissipator, including a pier cap, a pre-damaged section and a bridge pier section arranged sequentially along the height direction; the outer cylinder is embedded in the pier cap and the push rod is embedded in the bridge pier section.

[0015] Preferably, an extension section is provided between the bearing platform and the preset damage section; the dimensions of the bearing platform, the extension section, and the preset damage section decrease sequentially in the length and width directions.

[0016] Preferably, the middle part of the pre-damaged section is provided with a casting trough for casting the bridge pier section, and the concrete strength grade of the pre-damaged section is lower than that of the bridge pier section.

[0017] Preferably, the pier section is provided with an inner steel cage and an outer steel cage; the bottom ends of the inner steel cage and the outer steel cage are both embedded with a pre-set damaged section and a pier cap.

[0018] Preferably, the structural strength of the inner reinforcing cage is greater than that of the outer reinforcing cage, and the stirrup spacing of the outer reinforcing cage in the abutment, the pre-damaged section and the pier section is A, B and C respectively, where B > A and B > C.

[0019] Preferably, the plurality of said friction energy dissipators are located between the inner and outer reinforcing cages.

[0020] The application of the technical solution of the present invention has the following beneficial effects:

[0021] (1) In this invention, by sequentially setting an outer steel cage, a friction energy dissipator and an inner steel cage from the outside to the inside of the pier structure, the pier structure can be damaged and the energy dissipated layer by layer from the outside to the inside. The inner steel cage protects the central area of ​​the pier structure section, so that the pier structure remains vertical after the earthquake.

[0022] (2) In this invention, the friction energy dissipator includes an outer cylinder, a push rod, a piston, a friction sleeve, an elastic reset component, and a rotary reset assembly. On the one hand, energy dissipation can be achieved through the relative friction between the friction sleeve and the outer cylinder. On the other hand, the rotary reset assembly will rotate under the pressure of the push rod, thereby causing the rotary reset assembly to rotate relative to the push rod and the piston, thus achieving rotational friction energy dissipation.

[0023] (3) In this invention, the rotary reset assembly includes a rotating block and a guide bar. The inner wall of the outer cylinder is provided with a guide part for cooperating with the guide bar. One end of the push rod is provided with a serrated structure for contacting the friction block provided at the top of the guide bar. Through the cooperation of the guide bar, the push rod and the guide part, the rotary reset assembly and the piston are reset.

[0024] (4) In this invention, the end slope of the sawtooth structure is parallel or coplanar with the guide slope, which can guide the contact slope on the friction block during the process of the push rod being pressed or pulled, so that the guide bar can move into the guide groove of the outer cylinder when it is reset, thereby realizing the overall reset of the friction energy dissipator.

[0025] (5) In this invention, a pre-set damage section is set at the bottom of the pier segment. Under near-fault earthquake action, the pre-set damage section located on the outer side of the bottom of the pier segment undergoes active damage from large internal forces during the earthquake, resulting in a reduction in pier stiffness and an extension of the structural period during subsequent earthquakes, thus avoiding the dominant earthquake period. The beneficial effect of the damage of the pre-set damage section on the seismic isolation effect is utilized to improve the overall seismic performance of high-speed railway bridges under near-fault large and super-large earthquake action, avoiding the vicious cycle of pier damage interfering with the seismic isolation effect.

[0026] (6) In this invention, after the upper extension section of the pier is set on the upper part of the pier, the connection between the pier and the bridge pier is protected, making it easy to install rebar during construction and easy to repair after damage.

[0027] (7) In this invention, the outer steel cage is far from the neutral axis of the pier structure and has a high utilization rate. It can resist earthquakes of general strength. Under the action of near-fault earthquakes and super earthquakes, the longitudinal bars of the outer steel cage may break. The longitudinal bars of the inner steel cage are close to the neutral axis of the pier structure, protecting the concrete near the center of the cross section, improving the ductility of the pier, and ensuring that it still has a certain bearing capacity after the earthquake. It ensures that the pier is vertical or can be vertical after the damaged parts are removed and is easy to repair. Trains can pass through at a limited speed in the short term.

[0028] (8) In this invention, the ductile pier structure uses common concrete and steel bars, the construction process is simple, the project cost is low, and it can be easily applied to railway bridge construction.

[0029] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 This is a schematic diagram of a ductile bridge pier structure according to an embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the structure of a friction energy dissipator according to an embodiment of this application;

[0033] Figure 3 This is a schematic diagram of the friction energy dissipator configuration in an embodiment of this application;

[0034] Figure 4 This is a cross-sectional view (without section lines) of the friction energy dissipator in the embodiments of this application.

[0035] Figure 5 This is an embodiment of the present application. Figure 4 Enlarged detail of section A;

[0036] Figure 6 This is a schematic diagram of the initial working state of the friction energy dissipator in the embodiments of this application;

[0037] Figure 7 This is a schematic diagram of the friction energy dissipator under pressure in an embodiment of this application;

[0038] Figure 8 This is a schematic diagram of the reset working state of the friction energy dissipator in an embodiment of this application;

[0039] Figure 9 This is an embodiment of the present application. Figure 1Schematic diagram of the pre-set damage segment;

[0040] Figure 10 This is a schematic cross-sectional view (without section lines) of a ductile bridge pier structure in a preset damage section according to an embodiment of this application.

[0041] Among them, 1. Outer cylinder, 1.1. Guide part, 1.1.1. Guide slope, 1.1.2. Guide groove, 2. Push rod, 2.1. Serrated structure, 2.1.1. End slope, 3. Piston, 3.1. Limiting part, 4. Friction sleeve, 5. Elastic reset component, 6. Rotary reset assembly, 6.1 Rotating block, 6.2. Guide strip, 6.2.1. Contact slope, 6.2.2. Friction block, 7. Foundation, 8. Pre-set damage section, 8.1. Casting groove, 9. Pier section, 9.1. Tray top cap, 10. Upward section of foundation, 11. Inner steel cage, 12. Outer steel cage. Detailed Implementation

[0042] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims. Example:

[0043] See Figures 1 to 10 A friction energy dissipator and a ductile bridge pier structure are described in this embodiment, which is applied to the construction of bridge piers for high-speed railway bridges under near-fault earthquakes.

[0044] A ductile bridge pier structure, see Figure 1 The structure includes, from bottom to top along the height direction, a foundation 7, an extension section 10 on the foundation, a pre-damaged section 8, and a pier section 9. The pier section 9 is a solid main body with a rectangular or circular cross-section, and its top has a tray cap 9.1 for supporting the bridge. Multiple friction energy dissipators are installed at the bottom of the ductile pier structure. Specifically, the outer cylinder 1 of the friction energy dissipator is embedded in the foundation 7, and the push rod 2 at the top of the friction energy dissipator is embedded in the pier section 9. The push rod 2 and the outer cylinder 1 can move relative to each other in the vertical direction. Figure 3 As shown, when a ductile bridge pier structure is subjected to a near-fault earthquake, the internal force at the bottom of the pier is large. Seismic energy is dissipated through friction of the friction energy dissipator and yielding of the outer layer of steel reinforcement at the bottom of the pier, achieving a damping effect. A pre-set damage section 8 is set on the outer periphery of the bottom of pier segment 9. Energy dissipation is achieved through the destruction of the pre-set damage section 8, and the structural period is extended to avoid the dominant earthquake period, achieving a seismic isolation effect. The inner steel cage protects the central section of the pier, ensuring it remains in an elastic stage. After an earthquake, the pier remains vertical and retains a certain load-bearing capacity, allowing trains to pass at reduced speed. The pre-set damage section 8 is easy to repair. The specific structures of each component will be explained below.

[0045] See Figure 2 and Figure 4A friction energy dissipator includes an outer cylinder 1, a push rod 2, a piston 3, a friction sleeve 4, and an elastic reset member 5. The piston 3, friction sleeve 4, and outer cylinder 1 are coaxially arranged. The friction sleeve 4 is sleeved outside the piston 3, and its outer wall contacts the inner wall of the outer cylinder 1, allowing relative sliding between them. The push rod 2 and elastic reset member 5 are movably disposed at both ends of the outer cylinder 1, and the piston 3 is subjected to the forces applied by the push rod 2 and elastic reset member 5 at both ends, thereby achieving overall sliding of the piston 3 and friction sleeve 4 inside the outer cylinder 1. Energy dissipation is achieved through relative friction between the friction sleeve 4 and the outer cylinder 1. In this embodiment, the elastic reset member 5 is a spring, and a limiting part 3.1 for limiting the spring is provided at one end of the piston 3.

[0046] A friction energy dissipator further includes a rotary reset assembly 6 movably disposed between the push rod 2 and the piston 3. The two ends of the rotary reset assembly 6 are in contact with the push rod 2 and the piston 3, respectively. When the rotary reset assembly 6 is subjected to pressure from the push rod 2, it will transmit the pressure to the piston 3, causing the piston 3 to compress the elastic reset member 5 and drive the friction sleeve 4 to slide inside the outer cylinder 1, thereby dissipating energy. On the other hand, the rotary reset assembly 6 will rotate under the pressure of the push rod 2, thereby rotating the rotary reset assembly 6 relative to the push rod 2 and the piston 3, thereby dissipating energy through rotational friction.

[0047] In this embodiment, see Figures 5 to 8 The rotary reset assembly 6 includes a cylindrical rotating block 6.1. The outer circumferential surface of the rotating block 6.1 is provided with a plurality of guide strips 6.2. The length direction of the guide strips 6.2 is parallel to the axial direction of the outer cylinder 1. A wear-resistant friction block 6.2.2 is provided at the top of the guide strips 6.2 to extend the service life of the rotary reset assembly 6.

[0048] The inner wall of the outer cylinder 1 is provided with a guide portion 1.1 for cooperating with the guide strip 6.2. The guide portion 1.1 protrudes from the inner wall of the outer cylinder 1 and is used to limit and guide the rotary reset assembly 6. The guide portion 1.1 includes a plurality of guide slopes 1.1.1 for contacting the friction block 6.2.2 provided at the top end of the guide strip 6.2.

[0049] One end of the push rod 2 is provided with a serrated structure 2.1 for contacting the friction block 6.2.2 provided at the top of the guide bar 6.2. The end slope 2.1.1 of the serrated structure 2.1 is parallel to or coplanar with the guide slope 1.1.1.

[0050] The friction block 6.2.2 at the top of the guide bar 6.2 is provided with a contact slope 6.2.1, which is used to cooperate with the guide slope 1.1.1 or the end slope 2.1.1.

[0051] The guide portion 1.1 further includes a guide groove 1.1.2 connected between two adjacent guide ramps 1.1.1, and the guide groove 1.1.2 matches the guide strip 6.2.

[0052] In this embodiment, the outer diameter of the area enclosed by the friction blocks 6.2.2 on the guide strip 6.2 is larger than the outer diameter of the sawtooth structure 2.1 and smaller than the inner diameter of the outer cylinder 1, so that the contact slope 6.2.1 on the friction block 6.2.2 can simultaneously meet the contact requirements with the end slope 2.1.1 or the guide slope 1.1.1.

[0053] During assembly, the coverage area of ​​each end face slope 2.1.1 on the push rod 2 corresponds to the guide groove 1.1.2 area on the guide part 1.1, and during operation, there is no relative rotation between the push rod 2 and the outer cylinder 1. The rotary reset assembly 6 has three working states: initial working state, pressure working state, and reset working state.

[0054] See Figure 6 In the initial working state, the sawtooth structure 2.1 of the push rod 2 always keeps in contact with the guide bar 6.2 of the rotary reset assembly 6. Specifically, the end inclined surface 2.1.1 abuts against the contact inclined surface 6.2.1 of the friction block 6.2.2. The guide bar 6.2 is set inside the guide groove 1.1.2. When the relative force between the push rod 2 and the outer cylinder 1 applied by external factors is small, the push rod 2 squeezes the guide bar 6.2, and the guide bar 6.2 undergoes a small vertical reciprocating motion within the guide groove 1.1.2. At this time, energy is dissipated only through friction between the friction sleeve 4 and the outer cylinder 1.

[0055] See Figure 7 The pressure-bearing working state occurs when there is a large external force, such as during an earthquake. Due to the uneven force on the pier section 9 and the abutment 7, a large relative force will be generated between the push rod 2 and the outer cylinder 1, which will compress the push rod 2 downward. This will cause the rotary reset assembly 6, piston 3, friction sleeve 4 and elastic reset component 5 to be compressed and move downward as a whole inside the outer cylinder 1. At this time, the guide bar 6.2 is pushed out from the bottom of the guide groove 1.1.2 by the push rod 2. When pushed out, the end inclined surface 2.1.1 and the guide inclined surface 1.1.1 are coplanar. After the guide bar 6.2 is pushed out of the guide groove 1.1.2, since there is no guide groove 1.1.2 to limit the guide bar 6.2 on both sides, the guide bar 6.2 will start to rotate under the squeezing action of the end inclined surface 2.1.1 until the rotation is limited by the vertical edge of the sawtooth structure 2.1.

[0056] Referring to Figure 8, during the reset working state, when opposing relative forces are generated between the push rod 2 and the outer cylinder 1 (such as when the friction energy dissipator changes from a compressed state to a tensile state) or when the external force disappears, the piston 3, under the elastic action of the elastic reset member 5, will move upward, thereby pushing the rotating block 6.1. When the guide bar 6.2 returns to its upward position, it will contact a guide slope 1.1.1 on the guide part 1.1. The end slope 2.1.1 of the push rod 2, which matches the guide bar 6.2, will then contact the guide bar 6.2 after being coplanar with the guide slope 1.1.1. The contact surface 6.2.1 separates, and the push rod 2 continues to move upward. The friction block 6.2.2 of the guide bar 6.2 will move along the guide slope 1.1.1 under the elastic force transmitted by the piston 3 until it enters the adjacent guide groove 1.1.2 and contacts one end slope 2.1.1 at the bottom of the sawtooth structure 2.1 of the push rod 2 to achieve a limit. The friction block 6.2.2 on the guide bar 6.2 moves along the guide slope 1.1.1, which will drive the rotating block 6.1 to rotate, so that the rotary reset assembly 6 can simultaneously achieve reset and rotational friction energy dissipation.

[0057] See Figure 1 and Figure 3 The upper extension section 10 is located between the pier cap 7 and the pre-damaged section 8. The dimensions of the pier cap 7, the upper extension section 10, and the pre-damaged section 8 decrease sequentially in length and width. The connection between the upper extension section 10 and the pier is easily repaired after being damaged by an earthquake. In this embodiment, both the pier cap 7 and the upper extension section 10 are rectangular structures, and are poured in layers after the reinforcing steel is tied.

[0058] See Figure 9 The pre-damaged section 8 has a casting groove 8.1 in the middle for casting the pier section 9. The casting groove 8.1 runs through the pre-damaged section 8, allowing the bottom of the pier section 9 to be directly connected to the upper extension section 10 of the pier platform. The pre-damaged section 8 and the pier section 9 have the same circumferential structural dimensions and a height of 0.5-1 meter. The concrete strength grade of the pre-damaged section 8 is lower than that of the pier section 9, forming a vulnerable area on the outer periphery of the bottom of the pier section 9. During an earthquake, energy is dissipated through damage in this area, and it is easy to remove after damage, facilitating maintenance. Under near-fault earthquake action, the pre-damaged section 8, located on the outer side of the bottom of the pier section 9, undergoes significant active damage from internal forces, resulting in a reduction in pier stiffness and an extension of the structural period during subsequent earthquakes, thus avoiding the dominant earthquake period. Utilizing the beneficial effect of the damage to the pre-damaged section 8 on the seismic isolation effect improves the overall seismic performance of high-speed railway bridges under near-fault large and super-large earthquakes, avoiding a vicious cycle where pier damage interferes with the seismic isolation effect.

[0059] See Figure 3 and Figure 10The pier segment 9 is internally equipped with an inner reinforcing cage 11 and an outer reinforcing cage 12, with multiple friction energy dissipators located between the inner and outer reinforcing cages 11 and 12. The bottom ends of both the inner and outer reinforcing cages 11 and 12 are embedded with a pre-set damaged section 8, an extended section 10 on the pier cap, and the pier cap 7. The inner reinforcing cage 11 is located in the middle of the pier segment 9, protecting the concrete at the center of the pier segment 9's cross-section and ensuring the pier remains vertical and easily repaired after an earthquake.

[0060] The inner reinforcing cage 11 has a greater structural strength than the outer reinforcing cage 12. Compared to the outer reinforcing cage 12, the longitudinal reinforcement of the inner cage 11 uses steel bars with higher strength or larger diameter, along with denser stirrups to protect the core concrete in the middle of the ductile pier structure. These stirrups can be placed only at the bottom of pier segment 9 or arranged along the entire length of the ductile pier structure to ensure that the central section of the ductile pier structure does not undergo significant deformation under seismic loading. After the pre-set damaged segment 8 fails and spalls off, the pier bottom section still possesses a certain bearing capacity.

[0061] The reinforcement of the outer steel cage 12 is based on that of a traditional high-speed railway bridge pier. It is located near the outer periphery of the pier segment 9. The outer steel cage 12 is only covered by a protective layer of concrete. The stirrup spacing of the outer steel cage 12 in the abutment 7, the pre-damaged segment 8 and the pier segment 9 is A, B and C respectively, where B > A and B > C. This makes the outer steel cage 12 of the pre-damaged segment 8 weaker, guiding the damage caused by the earthquake to occur in the pre-damaged segment 8, so that it will be destroyed and dissipate energy first.

[0062] The construction method for the aforementioned ductile bridge pier structure is as follows:

[0063] Step 1: Tie and position the inner steel cage 11 and the outer steel cage 12 with the steel bars of the foundation 7 and the upper extension section 10 of the foundation, and fix the position of the friction energy dissipator. Pour the foundation 7 and the upper extension section 10 of the foundation in layers. When pouring, set a protective film on the top of the friction energy dissipator to prevent concrete from entering the gap between the push rod 2 and the outer cylinder 1.

[0064] Step 2: After completing the concrete pouring of the upper extension section 10 of the foundation, calculate whether the pre-damaged section 8 needs to be reinforced or the amount of reinforcement based on the actual project. After tying the steel bars of the pre-damaged section 8, pour the pre-damaged section 8 with low-strength concrete and mortar. During pouring, leave a hollow groove 8.1. The pouring height of the pre-damaged section 8 is 0.5 meters to 1 meter.

[0065] Step 3: Tie the reinforcing bars of pier segment 9, and pour high-strength concrete from the hollow groove 8.1 to pier segment 9.

[0066] The working process of the above-mentioned friction energy dissipator and ductile bridge pier structure is as follows:

[0067] When subjected to the small vibrations of high-speed rail operation, the piston 3 in the friction energy dissipator is driven by the push rod 2 and the elastic reset member 5 to drive the friction sleeve 4 to slide back and forth inside the outer cylinder 1, and energy is dissipated through the friction between the friction sleeve 4 and the outer cylinder 1.

[0068] Under near-fault earthquake action, the outer steel cage 12 and the pre-set damage section 8 at the bottom of the ductile pier structure experience greater stress. The steel bars in the outer steel cage 12 yield or even fracture, and the concrete in the pre-set damage section 8, lacking steel reinforcement, cracks rapidly and fails first, thus guiding and controlling the damage within the pre-set damage section 8. The friction energy dissipator, located close to the center of the cross-section, dissipates energy through friction by sliding the friction sleeve 4 inside the outer cylinder 1, and also through rotational friction energy dissipation by the rotating reset assembly 6 under the elastic force transmitted by the push rod 2 and piston 3. The inner steel cage 11, with its greater strength, protects the concrete near the center of the cross-section, ensuring the pier structure remains vertical. After the pre-set damage section 8 at the bottom of the pier segment 9 fails, the stiffness of the pier structure decreases and the structural period increases. By increasing the flexibility of the pier structure, the structural period is extended, avoiding the dominant period of near-fault earthquakes, reducing the transmission of seismic energy from the ductile pier structure to the bridge superstructure, preventing further damage to the ductile pier structure, and achieving both seismic reduction and isolation effects. After the earthquake, the extended section 10 on the pier cap is easy to repair, and the ductile pier structure is easy to repair after the pre-damaged section 8 is removed.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A frictional energy dissipator, characterized in that, The application relates to a rotary reset assembly and a bridge pier damage simulation device. The rotary reset assembly comprises an outer cylinder (1), a push rod (2), a piston (3), a friction sleeve (4) and an elastic reset member (5); the piston (3), the friction sleeve (4) and the outer cylinder (1) are coaxially arranged; the friction sleeve (4) is arranged outside the piston (3), the outer wall of the friction sleeve (4) is in contact with the inner wall of the outer cylinder (1), and relative sliding can occur between the outer wall and the inner wall; the push rod (2) and the elastic reset member (5) are movably arranged at two ends of the outer cylinder (1) respectively, and the two ends of the piston (3) bear the acting force exerted by the push rod (2) and the elastic reset member (5) respectively, so that the piston (3) and the friction sleeve (4) can slide integrally in the outer cylinder (1). The rotary reset assembly (6) is movably arranged between the push rod (2) and the piston (3), and the two ends of the rotary reset assembly (6) are in contact with the push rod (2) and the piston (3) respectively. The rotary reset assembly (6) comprises a rotary block (6.1), a plurality of guide strips (6.2) are arranged on the outer circumferential surface of the rotary block (6.1), and the length direction of the guide strips (6.2) is parallel to the axial direction of the outer cylinder (1). A guide portion (1.1) for cooperating with the guide strips (6.2) is arranged on the inner wall of the outer cylinder (1), and the guide portion (1.1) comprises a plurality of guide inclined surfaces (1.1.1) for being in contact with one end of the guide strips (6.2). One end of the push rod (2) is provided with a sawtooth structure (2.1) for being in contact with one end of the guide strips (6.2), and the end inclined surface (2.1.1) of the sawtooth structure (2.1) is parallel to or coplanar with the guide inclined surface (1.1.1). One end of the guide strip (6.2) is provided with a contact inclined surface (6.2.1) for cooperating with the guide inclined surface (1.1.1) or the end inclined surface (2.1.1).

2. A frictional energy dissipator according to claim 1, characterised in that The guide portion (1.1) further comprises a guide groove (1.1.2) connected between two adjacent guide inclined surfaces (1.1.1), and the guide groove (1.1.2) is matched with the guide strips (6.2).

3. A ductile bridge pier structure provided with a friction damper according to claim 1 or 2, characterized in that The bridge pier damage simulation device comprises a bearing platform (7), a preset damage section (8) and a pier section (9) which are sequentially arranged along the height direction; the outer cylinder (1) is embedded in the bearing platform (7), and the push rod (2) is embedded in the pier section (9).

4. A ductile bridge pier structure according to claim 3, wherein A bearing platform upper extension section (10) is further arranged between the bearing platform (7) and the preset damage section (8); the specifications of the bearing platform (7), the bearing platform upper extension section (10) and the preset damage section (8) in the length direction and the width direction are sequentially reduced.

5. A ductile bridge pier structure according to claim 3, wherein A pouring groove (8.1) for pouring the pier section (9) is arranged in the middle of the preset damage section (8), and the concrete strength grade of the preset damage section (8) is lower than that of the pier section (9).

6. A ductile bridge pier structure according to claim 3, wherein The inner layer of the pier section (9) is provided with an inner layer steel cage (11) and an outer layer steel cage (12); the bottom end of the inner layer steel cage (11) and the bottom end of the outer layer steel cage (12) are embedded in the preset damage section (8) and the bearing platform (7).

7. A ductile bridge pier structure according to claim 6, wherein The structural strength of the inner layer reinforcement cage (11) is greater than that of the outer layer reinforcement cage (12), the stirrup spacing of the outer layer reinforcement cage (12) between the bearing platform (7), the preset damage section (8) and the pier section (9) is A, B and C respectively, B>A and B>C.

8. A ductile bridge pier structure according to claim 6, wherein A plurality of the friction energy dissipaters are located between the inner layer reinforcement cage (11) and the outer layer reinforcement cage (12).

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