Structure and method for improving seismic performance of existing bridge pier with ductility and rocking coordination

Abstract

The application discloses a ductility and swing cooperative working existing bridge pier anti-seismic performance improving structure and method, belongs to the technical field of bridge anti-seismic reinforcement, and aims at the defects that the existing bridge pier anti-seismic mode is single, the self-resetting capacity after earthquake is poor, the traditional reinforcement construction is complicated, and the structure is prone to irreversible damage.The application sets a spliced steel casing on the outside of the existing bridge pier, pours concrete between the casing and the bridge pier to form a rigid whole, matches the bottom second energy dissipation and shock absorption unit and the upper first energy dissipation and shock absorption unit to form a multi-stage shock absorption system, simultaneously sets a steel cable linkage bridge and the casing, can conduct the bridge shaking load to the energy dissipation components to cooperatively dissipate energy, relies on the stress characteristics that the bridge pier top shakes and the bottom is stable, realizes self-adaptive graded energy dissipation under small, medium and large earthquakes, has good self-resetting capacity, is convenient to construct, has strong adaptability, can effectively avoid the structural damage of the bridge pier and the bridge beam falling risk, reduces the operation and maintenance cost, and significantly improves the overall anti-seismic performance and service stability of the old bridge.

Description

Technical Field

[0001] This invention belongs to the field of existing bridge reinforcement and seismic resistance technology, specifically relating to a structure and method for improving the seismic performance of existing bridge piers through ductility and swaying in synergy. Background Technology

[0002] Currently, many highway and municipal bridges in my country were built relatively early, and their piers have low seismic design standards. After long-term service, they generally suffer from surface weathering, corrosion, and structural performance degradation. Existing old bridge piers are mainly divided into two categories: reinforced concrete piers and steel piers. Traditional bridge pier seismic resistance systems rely solely on the ductile deformation of the structure itself to dissipate energy, which has obvious technical defects.

[0003] Traditional reinforcement techniques often employ methods such as external concrete encasing, steel plate bonding, and monolithic casting. These methods require large-scale demolition of the original structure, involve significant on-site wet work, and have long construction periods. They can easily disrupt bridge traffic, causing substantial impacts on transportation and the surrounding environment. Furthermore, traditionally reinforced bridge piers remain rigid seismic-resistant systems, making them susceptible to irreversible cracking and deformation damage under earthquake loads. This results in significant residual displacement after an earthquake, high repair difficulty, and high maintenance costs. They also fail to achieve post-earthquake self-resetting, making it difficult to meet the long-term safe service requirements of bridges in high-intensity seismic zones.

[0004] In response to the shortcomings of existing technologies, such as limited seismic resistance modes, poor post-earthquake self-healing ability, low construction efficiency, and limited adaptability, there is an urgent need to develop a lightweight seismic reinforcement and retrofitting technology that is compatible with both concrete and steel bridge piers, is easy to construct, has excellent seismic performance, and possesses self-resetting capabilities. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a structure and method for improving the seismic performance of existing bridge piers by coordinating ductility and sway, in order to solve the problem that the seismic performance of existing bridge piers is singular and their self-recovery ability after earthquakes is poor.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The seismic performance enhancement structure for existing bridge piers that combines ductility and sway is provided. It includes the existing bridge pier and the existing foundation located at its bottom, as well as a protective casing fitted and fixed to the outer surface of the existing bridge pier and a first energy-dissipating and damping unit disposed outside the protective casing. The protective casing is coaxially disposed on the outer surface of the existing bridge pier, and the bottom of the protective casing is spaced apart from the upper surface of the existing foundation. The protective casing and the outer surface of the existing bridge pier together form a casting chamber. A second energy-dissipating and damping unit is connected between the bottom of the protective casing and the upper surface of the existing foundation. The first energy-dissipating and vibration-damping unit includes multiple dampers arranged circumferentially on the outer surface of the casing. One end of each damper is hinged to the outer surface of the casing, and the hinge is located at the end away from the existing foundation. The other end of each damper is connected to a tensile universal ball joint, and the base of the tensile universal ball joint is fixed to the existing foundation. The second energy-dissipating and vibration-damping unit includes multiple first springs and buffer blocks arranged circumferentially on the outside of the existing bridge pier. One end of each first spring is fixedly connected to the bottom of the protective sleeve, and the other end is fixedly connected to the upper surface of the existing foundation. Each buffer block is embedded in the upper surface of the existing foundation, and the upper surface of the buffer block abuts against the bottom of the protective sleeve. Each buffer block, together with the existing foundation and the surface of the protective sleeve, forms a closed cavity covering each first spring.

[0007] Furthermore, the first energy-dissipating and vibration-damping unit also includes a movable ring and an annular support coaxially disposed on the outside of the existing bridge pier. The annular support is fixedly connected to the existing base. The movable ring is coaxially disposed on the inside of the annular support, and there is a gap between the movable ring and the inner surface of the annular support. The circumferential surface of the movable ring is connected to multiple second springs along the inner wall of the adjacent annular support, and each second spring is arranged in a circumferential array around the axis of the movable ring. The base of each tensile universal ball joint is fixedly connected to the surface of the movable ring.

[0008] Furthermore, an annular buffer airbag is provided at the gap between the movable ring and the annular support. The buffer airbag is coaxially arranged with the movable ring, and the outer surface of the buffer airbag abuts against the surfaces of the adjacent movable ring and the annular support. The outer surface of the buffer airbag is covered with a wear-resistant layer.

[0009] Furthermore, the circumferential surface of the casing is also circumferentially arrayed with multiple connecting blocks, each of which is detachably connected to the casing, and each connecting block is located at one end of the casing near the existing base. Each connecting block has a connector hinged to its outer surface, and multiple steel cables are fixed to the surface of each connector, with the free end of each steel cable fixed to the underside of the bridge.

[0010] Furthermore, each of the connecting blocks and the damper are arranged in a staggered manner at circumferential intervals.

[0011] Furthermore, the inner wall of the protective sleeve is provided with multiple grooves, and multiple connecting cylinders are also vertically fixed to the inner wall of the protective sleeve. Each groove and connecting cylinder is arranged in a circumferential array around the axis of the protective sleeve, and is also arranged in an array along the length direction of its axis.

[0012] A method for improving the seismic performance of existing bridge piers that work in coordination with ductility and sway, applied to the aforementioned structure for improving the seismic performance of existing bridge piers that work in coordination with ductility and sway, includes the following implementation steps; Step 1: Based on the dimensions of the existing piers, transport the precast casing to the construction site and install it on the outer surface of the existing piers. Roughen the outer surface of the existing piers corresponding to the casing and install reinforcing bars, with one end of each reinforcing bar matching each connecting casing. Place pads in the gap between the bottom of the casing and the existing foundation for temporary support and fixation. Step 2: Pour concrete into the casting cavity formed by the casing and the existing pier. During the concrete curing process, expand the existing foundation simultaneously. Tie the bottom of the ring bearing to the internal steel bars of the expanded existing foundation to form an integral load-bearing structure. Step 3: After all the concrete has cured, remove all the pads. Then, install the first spring and the buffer block in sequence at the gap between the casing and the existing foundation. At the same time, install the movable ring, the second spring, and the buffer airbag inside the annular support. After the movable ring is installed and adjusted, connect the two ends of each damper to the corresponding movable ring and the outer surface of the casing, and adjust them accordingly. Step 4: After the damper is adjusted, install the connecting blocks on the outer surface of the casing and install multiple connecting lugs at the bottom of the bridge. Then, pull the steel cable at each connecting block and the corresponding connecting lug, and apply a certain pre-tension to the installed steel cable to keep it taut.

[0013] The beneficial effects of this invention are as follows: 1. This invention uses a spliced ​​steel structure casing to form a casting chamber with the existing bridge pier. After the concrete is poured, it can form an integrated rigid whole with the original bridge pier, which thoroughly optimizes the overall stress system of the existing bridge pier. The overall reinforcement structure fully fits the original bridge pier foundation without damaging the original main structure of the bridge pier. While preserving the original vertical bearing capacity of the bridge, it significantly improves the overall stiffness and structural integrity of the bridge pier. 2. This invention constructs a multi-dimensional, hierarchical adaptive vibration reduction and energy dissipation system, which can achieve differentiated energy dissipation protection for small, medium, and large earthquakes. For small earthquakes, relying on the pre-positioned elastic energy dissipation system composed of a movable ring, annular support, and a second spring, in conjunction with buffer airbags, it prioritizes the dissipation of small seismic impacts, allowing only minor deformation of the damper, thus suppressing minor pier swaying and preventing vibration amplification. For moderate earthquakes, the top damper adaptively deflects at multiple angles through a universal ball joint, dissipating most of the horizontal vibration kinetic energy at the pier top. The bottom first spring deforms synchronously to assist in energy dissipation and store elastic potential energy, while the rubber buffer block provides flexible limiting support. The system achieves dual-layer, graded energy dissipation, ensuring the main body of the bridge pier remains in an elastic working state without irreversible structural damage, and can automatically reset after an earthquake. For major earthquakes, the vibration load generated by bridge swaying can be synchronously introduced into the multi-level energy dissipation system around the pier through steel cables for centralized absorption, effectively reducing the amplitude of bridge vibration and significantly reducing the relative displacement between the pier and the bridge. The dampers fully dissipate the energy of strong earthquakes when they reach their maximum stroke, and the first spring at the bottom is compressed to its limit range to provide strong elastic restoring force. The buffer block prevents the rigid impact between the casing and the foundation, preventing structural overturning and instability. The bidirectional reset force can significantly reduce the residual displacement of the structure, meeting the core seismic design requirements of "not collapsing under major earthquakes". Attached Figure Description

[0014] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is a schematic diagram of the existing pier and casing structure of the present invention; Figure 2 This is a side view of the existing bridge pier and casing of the present invention; Figure 3 This is a schematic diagram of the structure of the second energy-dissipating and vibration-damping unit of the present invention; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a schematic diagram of the internal structure of the annular support of the present invention. Figure 1 ; Figure 6 This is a schematic diagram of the internal structure of the annular support of the present invention. Figure 2 .

[0015] The following labels are shown in the attached diagram: 1 Existing pier, 2 Existing foundation, 3 Casing, 4 Damper, 5 Tensile universal ball joint, 6 First spring, 7 Buffer block, 8 Movable ring, 9 Annular support, 10 Second spring, 11 Buffer airbag, 12 Connecting block, 13 Connecting head, 14 Steel cable, 15 Connecting cylinder. Detailed Implementation

[0016] like Figures 1-6 As shown, The seismic performance enhancement structure for existing bridge piers that works in conjunction with ductility and sway includes an existing bridge pier 1 and an existing foundation 2 located at its bottom, as well as a protective casing 3 sleeved and fixed to the outer surface of the existing bridge pier 1 and a first energy-dissipating and damping unit set outside the protective casing 3; the protective casing 3 is coaxially set on the outer surface of the existing bridge pier 1, and the protective casing 3 is made of multiple steel structures spliced ​​together and fixed by bolts and nuts. The protective casing 3 and the outer surface of the existing bridge pier 1 together form a pouring chamber for accommodating concrete. The protective casing 3 is set close to the existing foundation 2, and the bottom of the protective casing 3 is spaced apart from the upper surface of the existing foundation 2. The bottom of the protective casing 3 and the upper surface of the existing foundation 2 are connected together by a second energy-dissipating and damping unit; The first energy-dissipating and vibration-damping unit includes four dampers 4 arranged circumferentially on the outer surface of the casing 3. One end of each damper 4 is hinged to the outer surface of the casing 3, and the hinge is located at the end away from the existing foundation 2. The other end of each damper 4 is connected to a tensile universal ball joint 5, and the base of the tensile universal ball joint 5 is fixed to the existing foundation 2 by bolts. The second energy-dissipating and vibration-damping unit includes eight first springs 6 arranged circumferentially on the outside of the existing pier 1 and four buffer blocks 7. One end of each first spring 6 is fixedly connected to the bottom of the protective sleeve 3 by bolts, and the other end is fixedly connected to the upper surface of the existing foundation 2 by bolts. The upper surface of the existing foundation 2 is provided with a groove for accommodating the buffer blocks 7. Each buffer block 7 is fitted into the upper surface of the existing foundation 2 through the groove, and the upper surface of the buffer block 7 abuts against the bottom of the protective sleeve 3. Each buffer block 7 is made of rubber material. Each buffer block 7, together with the surface of the existing foundation 2 and the protective sleeve 3, forms a closed cavity covering each first spring 6.

[0017] As shown in the figure, when reinforcing the seismic performance of the existing pier 1, the casing 3 is first assembled and then fixed to the outer surface of the existing pier 1, ensuring that there is a gap between the bottom of the casing 3 and the upper surface of the existing foundation 2. Then, wooden blocks, iron blocks, bricks, etc. are placed in this gap, and then concrete is poured into the pouring cavity formed by the casing 3 and the outer surface of the existing pier 1. During the concrete pouring process, the damper 4 can be installed and adjusted simultaneously. After the concrete curing is completed, all the blocks between the bottom of the casing 3 and the upper surface of the existing foundation 2 are removed, and then the first spring 6 is installed at this point. The upper and lower ends of each first spring 6 are fixedly connected to the casing 3 and the surface of the existing foundation 2. Finally, the buffer block 7 is installed, ensuring that the buffer blocks 7 form a ring together and together with the existing foundation 2 and the bottom of the casing 3 to form a closed area, and cover all the first spring 6 to reduce the interference of the external environment on the first spring 6 to a certain extent. When a minor earthquake occurs, the pre-tensioned force of the first spring 6 at the bottom of the casing 3 can press the steel casing 3 tightly against the foundation buffer block 7. The casing 3 and the existing pier 1 form a rigid whole through the pouring of concrete. Relying on the ductility and stiffness of the existing pier 1 itself, it remains completely stable. The damper 4 in the first energy dissipation and vibration reduction unit at the top of the casing 3 only undergoes a small deformation and dissipates only a small amount of vibration energy. The overall structure has no obvious lateral displacement or local stress concentration. The damping constraint at the top of the existing pier 1 can completely suppress the amplification of minor swaying. The vertical bearing capacity and lateral stability of the bridge are not affected. After the earthquake, it can be passed normally without any maintenance. There is no risk of performance degradation in long-term service. When subjected to a moderate earthquake, the existing pier 1 undergoes moderate bending deformation, and the casing 3 sways in a controllable manner synchronously with the upper part of the existing pier 1. The circumferential array dampers 4 at the top of the existing pier 1 adaptively deflect at multiple angles through the tensile universal ball joints 5 at both ends, continuously dissipating most of the horizontal vibration kinetic energy at the top of the pier, effectively weakening the large displacement of the pier top caused by the cantilever effect, and avoiding the hidden danger of the pier top hitting the upper cap beam and main beam. At the same time, multiple sets of first springs 6 at the bottom of the casing 3 compress and deform synchronously with the lifting of the casing 3, assisting in the consumption of the base vibration energy and storing elastic potential energy. The rubber buffer block 7 provides flexible support to limit the excessive lifting of the casing 3, realizing the dual-layer graded energy consumption of upper damping and bottom springs. The vibration energy is dispersed and consumed by the external replaceable shock absorption components. The main body of the existing pier 1 is always in the elastic working range and will not suffer irreversible structural damage such as cracking or peeling. After the earthquake, it can quickly restore its initial shape by relying on the spring force and damping rebound force. When a major earthquake occurs, the strong seismic force causes the casing 3 to sway significantly. Each damper 4 reaches its maximum effective stroke to fully dissipate the strong seismic energy. The first springs 6 at the bottom of the casing 3 are fully compressed to their limit range. The superposition of multiple springs provides a strong elastic restoring force. The rubber buffer block 7 forms an ultimate buffer limit, preventing the casing 3 from rigidly impacting the foundation and preventing the casing 3 from overturning and becoming unstable. After the seismic force dissipates, the elastic restoring force of the bottom spring combination and the rebound force of the top damping work together to pull the casing 3 and the upper part of the existing pier 1 to automatically reset, greatly reducing the overall residual displacement and meeting the seismic resistance requirements of not collapsing during a major earthquake and being able to quickly restore function after the earthquake.

[0018] In this embodiment, the first energy-dissipating and vibration-damping unit further includes a movable ring 8 and an annular support 9 coaxially disposed on the outside of the existing pier 1. The annular support 9 is fixedly connected to the existing base. The movable ring 8 is coaxially disposed on the inside of the annular support 9, and there is a movable gap between the outer surface of the movable ring 8 and the inner surface of the annular support 9. The upper and lower end faces and the outer ring surface of the movable ring 8 are all connected to the inner wall of the adjacent annular support 9 with a plurality of second springs 10. Each second spring 10 is circumferentially arrayed around the axis of the movable ring 8. One end of each second spring 10 is fixedly connected to the outer surface of the movable ring 8 by bolts, and the other end is fixedly connected to the inner wall of the annular support 9 by bolts. The base of each tensile universal ball joint 5 is fixedly connected to the surface of the movable ring 8 by bolts.

[0019] As shown in the figure, the annular support 9 is coaxially arranged with the existing pier 1 and fixed to the surface of the existing foundation 2. The movable ring 8 is coaxially arranged inside the annular support 9, and multiple second springs 10 are connected between the movable ring 8 and the annular support 9. This allows the movable ring 8 to swing up and down and left and right relative to the corresponding annular support 9 within a certain range. Each tensile universal ball joint 5 is fixed to the upper surface of the movable ring 8. Therefore, when the casing 3 shakes with the existing pier 1 during an earthquake, the casing 3 will synchronously drive the corresponding damper 4 to apply pressure or tension to the corresponding position of the movable ring 8. The movable ring 8 will then squeeze or pull the corresponding second springs 10, thereby dissipating energy through the cooperation of the second springs 10. The purpose of vibration reduction is, of course, that the energy-dissipating vibration reduction effect of each second spring 10 is significantly less than that of the damper 4, mainly used to absorb the impact of small or medium-sized earthquakes; when a large earthquake occurs, when the movable ring 8 moves to its limit position under the action of the damper 4, at this time, the surface of part of the movable ring 8 is compressed to the limit state by the corresponding multiple second springs 10, and correspondingly, the remaining multiple second springs 10 are stretched to the limit state, and each second spring 10 cannot absorb the impact of the large earthquake; at this time, the damper 4 will start to work and be responsible for absorbing the earthquake impact; therefore, the energy-dissipating vibration reduction effect of the movable ring 8, the ring bracket, and each second spring 10 can be effectively enhanced through cooperation; Each second spring 10 and the movable ring 8 form a pre-elastic graded energy dissipation system. Under small and medium earthquakes, the casing 3 drives the damping to push and pull the movable ring 8, and the multi-directional second springs 10 deform synchronously, prioritizing the dissipation of small earthquake impacts, sharing the damping working load, significantly reducing damping reciprocating fatigue loss, and extending the service life of the damping components. During a large earthquake, the movable ring 8 reaches its displacement limit, and the second spring 10 is compressed / stretched to its limit and then withdraws from the main energy dissipation function. The damper 4 then takes over the energy of the strong earthquake, realizing the adaptive graded energy dissipation logic of "springs handle small and medium earthquakes, and dampers resist large earthquakes". The circumferentially arranged second springs 10 can adapt to the pier swing in any direction. The movable ring 8 is subjected to uniform force without unilateral jamming, ensuring that multiple sets of dampers dissipate energy synchronously and collaboratively, significantly enhancing the structure's energy dissipation and damping capacity for small and medium earthquakes, and improving the graded damping and protection performance of the system.

[0020] In this embodiment, an annular buffer airbag 11 is provided at the gap between the movable ring 8 and the annular support 9. The buffer airbag 11 is coaxially arranged with the movable ring 8. The outer surface of the buffer airbag 11 is located at the gap between the movable ring 8 and the annular support. The buffer airbag 11 is filled with gas at a certain pressure, so that the outer surface of the buffer airbag 11 always abuts against the surfaces of the adjacent movable ring 8 and the annular support 9. The outer surface of the buffer airbag 11 is covered with a wear-resistant rubber layer.

[0021] As shown in the figure, a buffer airbag 11 is also provided at the gap between the movable ring 8 and the annular support 9, forming a dual composite buffer energy dissipation system with the circumferentially arranged second spring 10. When a medium or small earthquake occurs, the movable ring 8 will undergo multi-directional adaptive displacement with the damper 4. At this time, the gas inside the buffer airbag 11 will also flow accordingly. The buffer airbag 11 will stretch and compress with the corresponding second spring 10, and simultaneously expand and contract. Relying on the deformation of the internal compressed gas, it will dissipate the kinetic energy of the earthquake vibration, further improve the overall energy absorption efficiency under medium and small earthquake conditions, share the reciprocating force load of the second spring 10, and effectively alleviate the fatigue damage caused by the long-term cyclic deformation of the spring. The wear-resistant rubber on the outer layer of the airbag can reduce the friction loss caused by the relative sliding of the movable ring 8 and the annular support 9. The annular airbag fills the gap between the components in the entire area, and there is no dead angle of movement. Even a small sway in any direction of the existing pier 1 can simultaneously trigger the energy absorption effect of the airbag, comprehensively strengthening the energy dissipation and vibration reduction performance of the entire graded damping structure for medium and small earthquakes, and further optimizing the structural vibration suppression effect.

[0022] In this embodiment, the circumferential surface of the casing 3 is also circumferentially arrayed with four connecting blocks 12. Each connecting block 12 is detachably connected to the casing 3 by bolts and nuts. Each connecting block 12 is located at one end of the casing 3 near the existing base. Each connecting block 12 has a connector 13 hinged to its outer surface. Each connector 13 has three steel cables 14 fixed to its surface. The free ends of each steel cable 14 are fixed to the lower surface of the bridge. The connecting blocks 12 and the damper 4 are circumferentially staggered.

[0023] As shown in the diagram, the bridge and the casing 3 are integrated into a single force-bearing structure through the cooperation of the connecting block 12 and the steel cable 14. The steel cable 14 and the damper 4 are arranged in a staggered pattern around the perimeter to prevent interference with each other's force distribution. Furthermore, one end of the steel beam is hinged to the side surface of the casing 3 near its bottom, effectively enhancing the bridge's buffering effect during earthquakes. When an earthquake occurs, due to the physical characteristics of the existing pier 1, the existing pier 1 and the existing foundation 2 sway synchronously (the sway amplitude is smaller than that of the top of the existing pier 1 and the bridge itself). The end of the existing pier 1 furthest from the existing foundation 2 will swing. The higher the existing pier 1, the greater the sway of the existing pier 1 and the bridge. When the existing pier 1 and the bridge sway during an earthquake, the bottom of the bridge will synchronously drive the corresponding steel cable 14 to move together. The other end of the steel cable 14 will then transmit the tension to the casing 3 through the connector 13. The indirect vibration of the casing 3 causes it to sway synchronously, which in turn introduces the vibration load generated by the lateral displacement of the bridge into the entire multi-stage energy dissipation and damping components. This forces the casing 3 to be indirectly subjected to a greater seismic impact force. The casing 3 then dissipates energy and reduces vibration through components such as the damper 4, the first spring 6, and the second spring 10, directly reducing the vibration amplitude of the bridge itself and the swaying amplitude of the bridge. This significantly reduces the relative displacement between the bridge and the existing pier 1, avoiding the risks of bridge displacement, collision, and beam collapse. The articulated arrangement of the steel cable 14 can adapt to multi-directional seismic swaying without generating additional bending stress. The detachable connecting block 12 facilitates the later inspection and replacement of the steel cable 14, making maintenance convenient. This structure uniformly collects the vibration energy of the upper bridge into the energy dissipation system around the pier for centralized absorption, sharing the energy dissipation pressure of the existing pier 1 itself, further improving the overall seismic bearing capacity limit of the structure, and strengthening the collaborative seismic stability of the bridge and the existing pier 1.

[0024] In this embodiment, the inner wall of the protective sleeve 3 is provided with multiple grooves, and multiple connecting cylinders 15 are also vertically welded and fixed to the inner wall of the protective sleeve 3. Each groove and connecting cylinder 15 is arranged in a circumferential array around the axis of the protective sleeve 3, and is also arranged in an array along the length direction of its axis.

[0025] As shown in the figure, the casing 3 and the outer surface of the existing pier 1 together form a casting chamber. The groove on the inner wall of the casing 3 can improve the adhesion of the concrete in the later stage. The connecting cylinder 15 can be threaded to the steel bar to strengthen the connection strength between the steel bar and the casing 3. The two work together to form an integral load-bearing structure after the concrete is cast, thereby improving the seismic resistance of the existing pier 1.

[0026] A method for improving the seismic performance of existing bridge piers that work in coordination with ductility and sway, applied to the aforementioned structure for improving the seismic performance of existing bridge piers that work in coordination with ductility and sway, includes the following implementation steps; Step 1: Based on the dimensions of the existing pier 1, transport the precast casing 3 to the construction site. Assemble multiple sections of casing 3 on-site using bolts and nuts. Coaxially mount the assembled casing 3 onto the outer side of the existing pier 1 near the foundation. Roughen the outer surfaces of the existing pier 1 and casing 3 and install reinforcing bars, with one end of each reinforcing bar engaging with each connecting cylinder 15. Place pads in the gap between the bottom of casing 3 and the existing foundation 2 for temporary support and fixation, ensuring that casing 3 is centered, stable, and without deviation, providing a precise construction benchmark for subsequent concrete pouring and installation of vibration damping components. Step 2: Pour concrete into the casting cavity formed by the casing 3 and the exterior of the existing pier 1. During the concrete curing process, the existing foundation 2 is expanded simultaneously. The original foundation is expanded and poured. The bottom of the ring support 9 is tied and welded to the main reinforcing bars inside the expanded foundation, so that the ring support 9 and the expanded foundation form an integral load-bearing structure. Step 3: After all concrete has cured, ensure that all temporary support pads at the bottom of the casing 3 are precisely maintained, and that the design gap between the casing 3 and the existing foundation 2 is precisely maintained. At the gap between the bottom of the casing 3 and the existing foundation 2, install eight first springs 6 in a circumferential array. Secure the upper and lower ends of the first springs 6 to the bottom of the casing 3 and the upper surface of the existing foundation 2 respectively with bolts. Then, fit the rubber buffer blocks 7 into the preset grooves of the existing foundation 2, so that the upper surface of the buffer blocks 7 is in close contact with the bottom of the casing 3. Multiple sets of buffer blocks 7 form a ring-shaped closed structure, completely covering all the first springs 6, isolating them from external rainwater and wind and sand erosion, and protecting the bottom elastic energy-dissipating structure. After the bottom components are installed, a movable ring 8 is coaxially assembled inside the fixed annular support 9. Multiple sets of second springs 10 are circumferentially arrayed in the gap between the movable ring 8 and the annular support 9. At the same time, annular buffer airbags 11 with wear-resistant rubber layers are arranged in the gap, so that the airbags completely fill the gap and tightly abut against the components on both sides, forming a front-mounted composite graded energy dissipation structure. After the movable ring 8, second springs 10, and buffer airbags 11 are all installed and adjusted in place, four dampers 4 are circumferentially hinged to the outer side of the upper part of the casing 3. The outer end of the damper 4 is fixed to the surface of the movable ring 8 with bolts through a tensile universal ball joint 5, completing the linkage assembly of the damper 4 and the graded energy dissipation system. The deformation stroke, hinge flexibility, and force uniformity of all damping components are comprehensively adjusted and calibrated. Step 4: After completing the installation and commissioning of the damper 4 and the entire vibration reduction system, multiple sets of detachable connecting blocks 12 are installed circumferentially at staggered intervals on the outer side of the bottom end of the casing 3 near the foundation. The connecting blocks 12 are firmly fixed to the casing 3 with bolts and nuts. At the same time, multiple matching connecting ears are installed at the corresponding positions at the bottom of the bridge. Steel cables 14 are pulled and installed between each set of connecting blocks 12 and the corresponding bridge connecting ears. Each set of connecting blocks 12 is equipped with multiple steel cables 14. After the steel cables 14 are installed, a special tensioning device is used to apply a uniform and matched design pretension force to the steel cables 14, so that all steel cables 14 are kept taut and uniformly stressed, realizing the rigid linkage between the upper bridge and the existing bridge pier 1 seismic reinforcement structure. The seismic vibration load of the bridge can be effectively introduced into the energy dissipation system around the pier, improving the collaborative seismic resistance of the bridge and the existing bridge pier 1. Finally, all connectors, steel cable 14 pretension force, and component connection nodes are comprehensively inspected to ensure that the overall structure installation meets the standards.

[0027] The specific working principle of this invention is as follows: During minor earthquakes: Existing pier 1 has the inherent characteristics of a stable bottom and a larger amplitude of swaying at the top and bridge. Small earthquakes can easily cause small reciprocating swaying at the top and bridge. The casing 3 is cast into a rigid whole with the existing pier 1. The first spring 6 at the bottom is pre-tightened to press the buffer block 7, locking the displacement of the bottom structure. Relying on the pre-positioned composite energy dissipation system composed of the movable ring 8, the second spring 10 and the buffer airbag 11, combined with the slight deformation of the top damper 4, the small vibration energy at the top of the pier is dissipated. At the same time, the bottom of the bridge is reliably connected to the bottom of the casing 3 through the pre-tightened steel cable 14, which can transfer the small swaying load of the bridge to the casing 3 in real time. The vibration energy of the bridge is synchronously introduced into the first energy dissipation and damping unit and the second energy dissipation and damping unit around the casing 3, realizing the coordinated damping of the existing bridge and pier, and suppressing the amplification effect of high-level swaying. The steel cable 14 can effectively link the bridge and the existing pier 1 reinforcement structure, collect the swaying energy of the bridge to the casing 3 and the surrounding energy dissipation components for centralized dissipation, and significantly reduce the amplitude of independent swaying of the bridge.

[0028] During a moderate earthquake: Under moderate earthquake conditions, the existing pier 1 exhibits obvious cantilever deformation characteristics, with minimal displacement at the bottom and large bending and swaying amplitudes at the pier top and the upper bridge. This structure adopts a two-layer graded energy dissipation mechanism. The first spring 6 rises and compresses with the casing 3 to dissipate energy, and works in conjunction with the rubber buffer block 7 for flexible restraint to stabilize the foundation structure. The damper 4 dissipates the main horizontal vibration energy at the pier top through adaptive multi-angle deflection via the tensile universal ball joint 5. Each second spring 10 and the buffer airbag 11 preferentially share the impact load to achieve graded energy dissipation. At the same time, the steel cable 14 continuously transmits the vibration load generated by the large swing of the bridge to the casing 3. With the help of multiple sets of energy dissipation components around the circumference and bottom of the casing 3, energy is dissipated synchronously, sharing the energy dissipation pressure of the pier itself, and achieving integrated and coordinated earthquake resistance of the bridge and pier. Through the force transmission linkage of steel cable 14, the displacement of the pier top and the bridge as a whole caused by the cantilever effect of the existing pier 1 is effectively reduced, eliminating the hidden danger of the pier top hitting the cap beam and main beam. The vibration energy of the bridge and the existing pier 1 is consumed by the external complete set of shock absorption components, and the main body of the pier is always in an elastic working state without irreversible damage such as cracking or peeling.

[0029] During a major earthquake: Under the action of a strong earthquake, the sway amplitude of the existing pier 1 at a high position and the bridge increases sharply, and the bottom is prone to rigid impact and structural instability. At this time, the second spring 10 and the buffer airbag 11 reach the deformation limit and withdraw from the main energy dissipation. The top damper 4 works at full stroke to fully dissipate the strong earthquake energy. The bottom first spring 6 is compressed to the limit range to provide strong elastic recovery force. The buffer block 7 prevents the casing 3 from rigidly impacting the foundation. The steel cable 14, as the core force transmission component, can efficiently transmit the violent sway load of the bridge under a strong earthquake to the casing 3, and fully mobilize all energy dissipation components around the casing 3 and at the bottom to dissipate energy together, and concentrate the strong earthquake vibration energy of the bridge and pier. After the earthquake dissipates, the top and bottom energy dissipation components and the steel cable 14 work together in a two-way synergy to achieve rapid overall structural reset.

[0030] By utilizing the force transmission and energy dissipation mechanism of steel cable 14, the problem of high position of existing pier 1 and large swaying of the bridge is effectively overcome. The vibration reduction efficiency of the multi-stage energy dissipation components around and at the bottom of the casing 3 is fully utilized, which greatly improves the overall energy dissipation and vibration reduction capacity of the bridge. It can significantly reduce the relative displacement between existing pier 1 and the bridge, completely avoid major risks such as bridge displacement, collision, and beam collapse under major earthquakes, and prevent damage to the bottom structure and overturning of casing 3. The residual deformation of the structure is small, which perfectly matches the stress characteristics of existing pier 1, which is stable at the bottom and swaying at the top. It meets the seismic resistance requirements of not collapsing under major earthquakes and rapid functional recovery after earthquakes, and greatly improves the overall ultimate seismic bearing capacity and safety reserve of the bridge.

[0031] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A seismic performance enhancement structure for existing bridge piers that combines ductility and sway, comprising existing bridge piers (1) and existing foundations (2) located at their bases, characterized in that: It also includes a protective sleeve (3) that is fitted and fixed on the outer surface of the existing pier (1) and a first energy-dissipating and vibration-damping unit set outside the protective sleeve (3); the protective sleeve (3) is coaxially set on the outer surface of the existing pier (1), and the bottom of the protective sleeve (3) is spaced apart from the upper surface of the existing foundation (2). The protective sleeve (3) and the outer surface of the existing pier (1) together form a casting chamber. The bottom of the protective sleeve (3) and the upper surface of the existing foundation (2) are connected together by a second energy-dissipating and vibration-damping unit. The first energy-dissipating and vibration-damping unit includes multiple dampers (4) arranged circumferentially on the outer surface of the casing (3). One end of each damper (4) is hinged to the outer surface of the casing (3), and the hinge is located at the end away from the existing foundation (2). The other end of each damper (4) is connected to a tensile universal ball joint (5), and the base of the tensile universal ball joint (5) is fixed to the existing foundation (2). The second energy-dissipating and vibration-damping unit includes multiple first springs (6) arranged circumferentially on the outside of the existing pier (1) and buffer blocks (7). One end of each first spring (6) is fixedly connected to the bottom of the protective sleeve (3), and the other end is fixedly connected to the upper surface of the existing foundation (2). Each buffer block (7) is embedded in the upper surface of the existing foundation (2), and the upper surface of the buffer block (7) abuts against the bottom of the protective sleeve (3). Each buffer block (7), together with the surface of the existing foundation (2) and the protective sleeve (3), forms a closed cavity covering each first spring (6).

2. The existing bridge pier seismic performance enhancement structure with ductility and swaying working in tandem as described in claim 1, characterized in that: The first energy-dissipating and vibration-damping unit also includes a movable ring (8) and an annular support (9) coaxially disposed on the outside of the existing pier (1). The annular support (9) is fixedly connected to the existing base. The movable ring (8) is coaxially disposed on the inside of the annular support (9), and there is a gap between the movable ring (8) and the inner surface of the annular support (9). The circumferential surface of the movable ring (8) is connected to the inner wall of the adjacent annular support (9) by a plurality of second springs (10), and each second spring (10) is arranged in a circumferential array around the axis of the movable ring (8). The base of each tensile universal ball joint (5) is fixedly connected to the surface of the movable ring (8).

3. The existing bridge pier seismic performance enhancement structure according to claim 2, characterized in that: A ring-shaped buffer airbag (11) is provided at the gap between the movable ring (8) and the annular support (9). The buffer airbag (11) is coaxially arranged with the movable ring (8), and the outer surface of the buffer airbag (11) abuts against the surfaces of the adjacent movable ring (8) and the annular support (9). The outer surface of the buffer airbag (11) is covered with a wear-resistant layer.

4. The existing bridge pier seismic performance enhancement structure with ductility and swaying working in synergy as described in claim 3, characterized in that: The circumferential surface of the casing (3) is also circumferentially arrayed with multiple connecting blocks (12). Each connecting block (12) is detachably connected to the casing (3), and each connecting block (12) is located at one end of the casing (3) near the existing base. Each connecting block (12) has a connector (13) hinged to its outer surface. Each connector (13) has multiple steel cables (14) fixed to its surface, and the free end of each steel cable (14) is fixed to the lower surface of the bridge.

5. The existing bridge pier seismic performance enhancement structure according to claim 4, characterized in that: Each of the connecting blocks (12) and the damper (4) is arranged circumferentially and alternately.

6. The existing bridge pier seismic performance enhancement structure according to claim 5, characterized in that: The inner wall of the protective sleeve (3) is provided with multiple grooves, and multiple connecting cylinders (15) are also vertically fixed on the inner wall of the protective sleeve (3). Each groove and connecting cylinder (15) is arranged in a circumferential array around the axis of the protective sleeve (3) and also arranged in an array along the length direction of its axis.

7. A method for improving the seismic performance of existing bridge piers through ductility and swaying in coordination, applied in the seismic performance improvement structure for existing bridge piers through ductility and swaying in coordination as described in any one of claims 1-6, characterized in that: The implementation steps include the following; Step 1: According to the dimensions of the existing pier (1), transport the precast casing (3) to the construction site and fix it on the outer surface of the existing pier (1). Roughen the outer surface of the existing pier (1) and the casing (3) and install reinforcement bars. One end of each reinforcement bar is matched with each connecting cylinder (15). Place pads in the gap between the bottom of the casing (3) and the existing foundation (2) for temporary support and fixation. Step 2: Pour concrete into the casting cavity formed by the casing (3) and the exterior of the existing pier (1). During the curing process of the concrete, the existing foundation (2) is expanded simultaneously. The bottom of the ring support (9) is tied and fixed to the internal steel bars of the expanded existing foundation (2) to form an overall load-bearing structure. Step 3: After all concrete has cured, remove all pads. Then, install the first spring (6) and buffer block (7) in sequence at the gap between the casing (3) and the existing foundation (2). At the same time, install the movable ring (8), the second spring (10), and the buffer airbag (11) inside the annular support (9). After the movable ring (8) is installed and adjusted, connect the two ends of each damper (4) to the corresponding movable ring (8) and the outer surface of the casing (3), and adjust them. Step 4: After the damper (4) is debugged, install each connecting block (12) on the outer surface of the casing (3) and install multiple connecting ears at the bottom of the bridge. Then pull the steel cable (14) at each connecting block (12) and the corresponding connecting ear, and apply a certain pre-tightening force to the installed steel cable (14) to keep it taut.

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