Energy dissipation device for improving seismic resistance of prefabricated assembly steel pipe concrete bridge pier

Abstract

The application discloses a kind of energy dissipation and shock absorption devices for improving the seismic performance of segmental assembled steel pipe concrete pier, and belongs to the field of bridge engineering construction, which comprises a load-bearing roof, a load-bearing floor, a pull rod and a foot plate.The load-bearing roof and the load-bearing floor are respectively fixed by welding at the corresponding joint of the segmental assembled steel pipe concrete pier, and the pull rod is anchored between the load-bearing roof and the load-bearing floor by a bolt joint.The pier bottom pull rod is installed in the reserved hole in the foot plate on the top of the pile cap.The application improves the energy dissipation of segmental assembled steel pipe concrete pier, enhances the connection between pier segments, and reduces the pier top displacement during an earthquake by coordinating the stress and deformation between segments.The damaged pull rod can be replaced in time after the earthquake, and the pier has good post-earthquake repairability.

Description

TECHNICAL FIELD The present application belongs to the field of bridge engineering, and particularly relates to a kind of energy dissipation device for improving the seismic performance of precast and assembled steel pipe concrete pier. BACKGROUND The precast and assembled reinforced concrete pier is currently mainly used in highway bridges and canal bridges in low intensity areas, because these projects have high requirements on construction environment and construction period, and can fully exert the advantages of factory precast. The disadvantages of serious damage at the bottom joint of segmental assembled pier, poor energy dissipation and high displacement demand at the pier top limit its promotion in medium and high intensity areas. The large displacement at the pier top puts forward higher requirements for the anti-falling beam design of the upper structure of this kind of pier.

[0001] With the improvement of the connection and assembly technology between segments, some precast piers with high vertical bearing capacity and suitable for high intensity areas have been proposed and studied, and the segment precast and assembled steel pipe concrete pier is one of them. The use of steel pipe to confine concrete can greatly improve the axial bearing capacity of the component. At the same time, because steel has good ductility, the steel pipe concrete pier not only has high bearing capacity, but also has good horizontal bearing capacity. During the processing of precast components, the steel pipe can be used as the lateral formwork of concrete at the same time, which can improve the work efficiency and has economic benefits.

[0002] Compared with the monolithic cast-in-place pier, the precast and assembled steel pipe concrete pier has lower energy dissipation under seismic action, and needs to add energy dissipation devices to improve it. The energy dissipation devices currently developed in China for precast and assembled piers are mainly divided into three categories: internal energy dissipation devices, such as setting energy dissipation steel bars inside the joint of segmental piers; external energy dissipation devices, such as setting dampers or mild steel dampers outside the joint of segmental piers; and pier bottom energy dissipation devices, such as setting energy dissipation bearings at the connection between the pier bottom and the pile cap. The existing energy dissipation devices have their own advantages and disadvantages, and the internal energy dissipation device has poor post-earthquake repairability, so the external energy dissipation device with good durability can be the first choice for design.

[0003] In recent years, the seismic design of structures has increasingly focused on performance-based design methods, hoping to make the structure have post-earthquake recovery performance through reasonable and ingenious design to minimize the economic loss caused by earthquakes. Prestressed segmental precast and assembled bridge piers have been deeply researched abroad and widely used in low-intensity areas. The segments of such bridge piers are connected into a whole through prestressed axial connection and provide load-carrying capacity and self-centering capacity by prestress. The response of the prestressed segmental precast and assembled bridge pier under earthquake action can be metaphorically compared to a roly-poly rocking structure. When the bending moment generated by external loads reaches the resisting bending moment provided by the self-weight and prestress of the structure, the pier begins to rotate around the pier bottom, and the joint between the pier bottom and the foundation contact part opens. The setting of energy dissipation devices at the joint between the pier bottom and the adjacent bridge pier segment joint can effectively dissipate seismic energy and reduce the damage of the structure itself. Since the opening of the joint between the segments under earthquake action will cause large pier top displacement, the external energy dissipation device should also have the ability to control the deformation at the joint while ensuring that there is no additional residual displacement after the earthquake. The external energy dissipation devices currently proposed at home and abroad have the problems of large additional residual displacement, insufficient self-stiffness to control the deformation at the joint, and insignificant energy dissipation and seismic mitigation effect. SUMMARY To solve the above problems, the purpose of the present application is to provide a kind of energy dissipation and seismic mitigation device for improving the seismic performance of precast and assembled steel pipe concrete bridge pier, which is convenient to construct, has no additional residual displacement, can be repaired after earthquake, can effectively control the deformation at the joint and improve the seismic performance of precast and assembled steel pipe concrete bridge pier.

[0004] The technical scheme adopted by the present application is as follows:

[0005] An energy dissipation and seismic mitigation device for improving the seismic performance of precast and assembled steel pipe concrete bridge pier, comprising a first load-bearing top plate, a foot plate, a second load-bearing top plate, a load-bearing bottom plate and a pull rod. The first load-bearing top plate and the load-bearing bottom plate are fixed perpendicular to the first steel pipe concrete segment, and the second load-bearing top plate is fixed perpendicular to the second steel pipe concrete segment. The pull rod is evenly distributed between the first load-bearing top plate and the foot plate and between the second load-bearing top plate and the load-bearing bottom plate. The upper end of the pull rod is welded to a base, and the upper end of the pull rod is connected to the first load-bearing top plate and the second load-bearing top plate through the base. The lower end of the pull rod is threadedly connected to the foot plate and connected to the load-bearing bottom plate and fixed by a nut. The foot plate is fixed to the pile cap by anchor bolts.

[0006] The first steel pipe concrete segment, the second steel pipe concrete segment and the third steel pipe concrete segment are circular steel pipes or rectangular steel pipes. A PVC pipe is fixed in the center of the steel pipe, a prestressed tendon is installed in the PVC pipe, and concrete is poured in the space between the inside of the steel pipe and the outside of the PVC pipe. The lower end of the prestressed tendon is anchored in the pile cap by an anchor, and the upper end of the prestressed tendon passes through the PVC pipes in the first steel pipe concrete segment, the second steel pipe concrete segment and the third steel pipe concrete segment and is anchored to the pier cap by an anchor.

[0007] The thickness of the first load-bearing top plate, foot plate, second load-bearing top plate, and load-bearing bottom plate shall not be less than the maximum diameter of the tie rod.

[0008] The first load-bearing top plate and the load-bearing bottom plate are welded and fixed to the first steel pipe concrete segment perpendicularly to each other, and the second load-bearing top plate is welded and fixed to the second steel pipe concrete segment perpendicularly to each other. The welding method adopts full penetration weld connection.

[0009] The diameter of the reserved tie rod hole in the first load-bearing top plate, the second load-bearing top plate, and the load-bearing bottom plate is 4mm-5mm larger than the diameter of the tie rod, and the diameter of the base at the upper end of the tie rod is 3cm-4cm larger than the diameter of the reserved tie rod hole.

[0010] The tie rod is made of ordinary steel bars, high-strength steel bars, or shape memory alloys, and is wrapped with a layer of polytetrafluoroethylene anti-corrosion material or other materials with a low coefficient of friction.

[0011] The advantages of this invention are:

[0012] It is easy to construct, effectively restricts deformation between steel-concrete composite segments, improves the energy dissipation capacity of steel-concrete composite segmental piers, and allows for timely replacement of damaged tie rods after an earthquake, demonstrating excellent repairability without causing additional post-earthquake residual displacement. Its main advantages include:

[0013] 1. During an earthquake, when the load-bearing top slab and load-bearing bottom slab rotate relative to each other with adjacent steel-concrete composite segments, the outer rotating tie rods limit the opening of the joints by bearing tensile force. The tensile force is mainly provided by their axial stiffness. The inner rotating tie rods are not subjected to pressure due to the structural characteristics of the bolt joints. Therefore, there will be virtually no residual displacement after the earthquake caused by the buckling deformation of the tie rods. After the earthquake, only the damaged tie rods need to be replaced in time, which has good post-earthquake repairability.

[0014] 2. The relative rotation between adjacent steel-concrete composite segments is very small, and there will be no bending of the tie rods during rotation. Therefore, there is basically no phenomenon of the tie rods getting stuck with the load-bearing plate after bending. When the load-bearing top plate and the load-bearing bottom plate may experience relative displacement with the adjacent steel-concrete composite segments, all tie rods participate in the work and become shear-resistant members, which can improve the shear bearing capacity of the steel-concrete composite pier.

[0015] 3. During an earthquake, the tie rod undergoes elastoplastic deformation to dissipate seismic energy while suppressing the deformation between steel-concrete composite segments, without buckling. This improves the energy dissipation of the structure and reduces the displacement requirement at the pier top.

[0016] 4. The material of the tie rod can be easily and flexibly selected from ordinary steel bars, high-strength steel bars or shape memory alloys, etc. By changing the length, number and diameter of the tie rod, the limiting effect of the tie rod on the steel tube concrete segment can be adjusted, thereby adjusting the energy dissipation of the structure and the displacement of the pier top during earthquakes.

[0017] 5. The load-bearing plate is easy to construct, requiring only welding to the corresponding position of the steel pipe concrete segment. The construction method is mature and economical. Attached Figure Description Figure 1 This is a schematic diagram illustrating the application of the tie rod energy dissipation and shock absorption device of the present invention;

[0018] Figure 2 (a) is an AA cross-sectional view of a steel-concrete composite pier segment;

[0019] Figure 2 (b) is another AA section view of a steel-concrete composite pier segment;

[0020] Figure 3 This is a front view of the structure of the tie rod energy dissipation and shock absorption device of the present invention;

[0021] Figure 4 (a) is a top view of a structure of the tie rod energy dissipation and vibration reduction device of the present invention;

[0022] Figure 4 (b) is a top view of another structure of the tie rod energy dissipation and shock absorption device of the present invention;

[0023] In the diagram: 1. First load-bearing top slab, 2. Load-bearing bottom slab, 3. Base, 4. PVC pipe, 5. Prestressed tendon, 6. Anchor, 7. Pier cap, 8. Third steel-concrete pipe segment, 9. Second steel-concrete pipe segment, 10. Second load-bearing top slab, 11. Nut, 12. First steel-concrete pipe segment, 13. Tie rod, 14. Foot plate, 15. Pier cap, 16. Anchor bolt. Detailed Implementation The invention will now be further described with reference to the accompanying drawings.

[0024] like Figure 1 , Figure 3 and Figure 4As shown, an energy-dissipating and vibration-damping device for improving the seismic resistance of precast steel-concrete composite bridge piers includes a first load-bearing top plate 1, a foot plate 14, a second load-bearing top plate 10, a load-bearing bottom plate 2, and tie rods 13. The first load-bearing top plate 1 and the load-bearing bottom plate 2 are fixed perpendicularly to the first steel-concrete composite segment 12, and the second load-bearing top plate 10 is fixed perpendicularly to the second steel-concrete composite segment 9. Tie rods 13 are placed between the first load-bearing top plate 1 and the foot plate 14, and between the second load-bearing top plate 10 and the load-bearing bottom plate 2. The upper end of the tie rod 13 is welded to a base 3, and the upper end of the tie rod 13 is connected to the first load-bearing top plate 1 and the second load-bearing top plate 10 respectively through the base 3. The lower end of the tie rod 13 is threaded to the foot plate 14 and connected to the load-bearing bottom plate 2 respectively and fixed by nuts 11. The foot plate 14 is fixed to the pier cap 15 by anchor bolts 16.

[0025] like Figure 2 As shown, the first steel-concrete pipe segment 12, the second steel-concrete pipe segment 9, and the third steel-concrete pipe segment 8 are circular or rectangular steel pipes. A PVC pipe 4 is fixed at the center of the steel pipe, and prestressing tendons 5 are installed inside the PVC pipe 4. Concrete is poured in the space between the inside of the steel pipe and the outside of the PVC pipe 4. The lower end of the prestressing tendon 5 is anchored to the pier cap 15 by the anchor 6. The prestressing tendon 5 passes through the PVC pipe 4 in the first steel-concrete pipe segment 12, the second steel-concrete pipe segment 9, and the third steel-concrete pipe segment 8, respectively. The upper end of the prestressing tendon 5 is anchored to the pier cap 7 by the anchor 6.

[0026] The thickness of the first load-bearing top plate 1, foot plate 14, second load-bearing top plate 10, and load-bearing bottom plate 2 shall not be less than the maximum diameter of the tie rod 13.

[0027] The first load-bearing top plate 1, the load-bearing bottom plate 2, and the first steel pipe concrete segment 12 are welded and fixed perpendicularly to each other. The second load-bearing top plate 10 and the second steel pipe concrete segment 9 are welded and fixed perpendicularly to each other. The welding method adopts full penetration weld connection to ensure that the axial force of the tie rod 13 can be reliably transmitted.

[0028] The diameter of the holes for the pre-reserved tie rod 13 in the first load-bearing top plate 1, the second load-bearing top plate 10, and the load-bearing bottom plate 2 is 4mm-5mm larger than the diameter of the tie rod 13, and the diameter of the upper base 3 of the tie rod 13 is 3cm-4cm larger than the diameter of the pre-reserved tie rod 13 holes.

[0029] The tie rod 13 is made of ordinary steel bars, high-strength steel bars, or shape memory alloys, etc. A layer of polytetrafluoroethylene anti-corrosion material or other material with low friction coefficient is wrapped around the tie rod 13 to ensure that the tie rod 13 is not compressed when it is subjected to pressure by relative sliding with the first load-bearing top plate 1, the second load-bearing top plate 10, and the load-bearing bottom plate 2. At the same time, the durability of the tie rod 13 can also be guaranteed.

[0030] In this invention, the foot plate 14 is manufactured in the factory according to the dimensions of the foundation 15. A hole for tie rods 13 is pre-drilled at the corresponding position in the center of the foot plate 14, and the hole should be machined into an internal thread. Anchor bolt holes 16 are pre-drilled at the edge of the foot plate 14. According to design requirements, appropriate types of high-strength steel bars, ordinary steel bars, or shape memory alloys are selected as the tie rods 13 and machined into bolt shapes. Vertical spacing is maintained between the second load-bearing top plate 10 and the load-bearing bottom plate 2, and between the first load-bearing top plate 1 and the foot plate 14. The spacing is determined by the length of the tie rods 13. The center of the pre-drilled tie rod hole in the first load-bearing top plate 1 and the center of the corresponding pre-drilled tie rod hole in the foot plate 14 are on the same vertical line. The center of the pre-drilled tie rod hole in the second load-bearing top plate 10 and the center of the corresponding pre-drilled tie rod hole in the load-bearing bottom plate 2 are also on the same vertical line. The foundation 15 is cast and cured on-site according to the actual design dimensions during construction. The foot plate 14 is manufactured in the factory with the same size and shape as the top surface of the foundation 15, and the internal threaded channel of the tie rod 13 and the channel of the anchor bolt 7 are accurately reserved.

Claims

1. An energy-dissipating and vibration-damping device for improving the seismic resistance of precast assembled steel-concrete composite bridge piers, characterized in that: The structure includes a first load-bearing top plate (1), a foot plate (14), a second load-bearing top plate (10), a load-bearing bottom plate (2), and tie rods (13). The first load-bearing top plate (1) and the load-bearing bottom plate (2) are fixed perpendicularly to each other with the first steel pipe concrete segment (12), and the second load-bearing top plate (10) is fixed perpendicularly to each other with the second steel pipe concrete segment (9). Tie rods (13) are placed between the first load-bearing top plate (1) and the foot plate (14), and between the second load-bearing top plate (10) and the load-bearing bottom plate (2). The upper end of the tie rod (13) is welded with a base (3), and the upper end of the tie rod (13) is connected to the first load-bearing top plate (1) and the second load-bearing top plate (10) respectively through the base (3). The lower end of the tie rod (13) is threaded to the foot plate (14) and connected to the load-bearing bottom plate (2) respectively, and fixed with nuts (11). The foot plate (14) is connected to the ground anchor bolts (16). The pier cap (15) is fixed; the first steel pipe concrete segment (12), the second steel pipe concrete segment (9), and the third steel pipe concrete segment (8) are circular steel pipes or rectangular steel pipes, with PVC pipes (4) fixed in the center of the steel pipes, and prestressing tendons (5) installed inside the PVC pipes (4). Concrete is poured in the space between the inside of the steel pipes and the outside of the PVC pipes (4). The lower end of the prestressing tendons (5) is anchored in the pier cap (15) through anchors (6). The prestressing tendons (5) pass through the PVC pipes (4) in the first steel pipe concrete segment (12), the second steel pipe concrete segment (9), and the third steel pipe concrete segment (8), respectively. The upper end of the prestressing tendons (5) is anchored to the pier cap (7) through anchors (6). The tie rod (13) is an ordinary steel bar, a high-strength steel bar, or a shape memory alloy. A layer of polytetrafluoroethylene anti-corrosion material or a material with a low coefficient of friction is wrapped around the outside of the tie rod.

2. The energy-dissipating and vibration-damping device for improving the seismic resistance of precast assembled steel-concrete bridge piers as described in claim 1, characterized in that: The thickness of the first load-bearing top plate (1), foot plate (14), second load-bearing top plate (10), and load-bearing bottom plate (2) is not less than the maximum diameter of the tie rod (13).

3. The energy-dissipating and vibration-damping device for improving the seismic resistance of precast assembled steel-concrete bridge piers as described in claim 1, characterized in that: The first load-bearing top plate (1) and the load-bearing bottom plate (2) are welded and fixed perpendicularly to each other to the first steel pipe concrete segment (12), and the second load-bearing top plate (10) and the second steel pipe concrete segment (9) are welded and fixed perpendicularly to each other to each other. The welding method adopts full penetration weld connection.

4. The energy-dissipating and vibration-damping device for improving the seismic resistance of precast assembled steel-concrete bridge piers as described in claim 1, characterized in that: The diameter of the reserved tie rod (13) hole in the first load-bearing top plate (1), the second load-bearing top plate (10) and the load-bearing bottom plate (2) is 4mm-5mm larger than the diameter of the tie rod (13), and the diameter of the upper base (3) of the tie rod (13) is 3cm-4cm larger than the diameter of the reserved tie rod (13) hole.

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