Sliding-swinging section prefabricated and assembled double-layer concrete filled steel tube combined pier column

Abstract

The invention discloses a sliding-swinging section prefabricated and assembled double-layer concrete-filled steel tube combined pier column which comprises double-layer concrete-filled steel tube prefabricated sections with concave-convex joints, polytetrafluoroethylene plates, internal prestressed tendons, anchoring parts, a bearing platform and a cover beam, wherein the double-layer concrete-filled steel tube prefabricated sections are provided with concave-convex joints; the double-layer concrete-filled steel tube prefabricated section with the concave-convex connector comprises an outer steel tube, high-strength non-shrinkage concrete and an inner steel tube, and a pair of polytetrafluoroethylene plates is bonded between every two adjacent sections to achieve the sliding shock insulation effect. The inner steel pipe is provided with a pair of convex and concave joints for limiting the sliding distance; the internal prestressed tendons penetrate through the double-layer concrete-filled steel tube prefabricated sections needing to be connected from the center of the inner steel tube to form the section prefabricated and assembled double-layer concrete-filled steel tube pier column, and a swing seismic mitigation and isolation system capable of resetting is formed between the bottom section of the pier column and the bearing platform. The structure has the advantages of being outstanding in dynamic load resistance, allowing components to generate large deformation and being rapid in construction, and is suitable for various requirements of bridge damping and catastrophe control in active fault areas.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering and composite structure technology, specifically relating to a sliding-swing segmental prefabricated double-layer steel-concrete composite pier column. Background Technology

[0002] Bridge engineering is a crucial component of lifeline engineering. Bridge collapse during an earthquake poses significant challenges to disaster relief efforts and has a substantial impact on socio-economic development. Compared to conventional seismic excitation, permanent ground displacement induced by cross-fault seismic motion leads to large deformations in bridge structures, causing critical components to enter strong nonlinearity and resulting in severe damage. This has become a critical issue in my country's new era of transportation infrastructure construction and disaster prevention and mitigation. While sliding isolation methods prevent the transmission of seismic motion to the superstructure by setting up sliding layers, their drawback is the difficulty in automatic reset after sliding. In contrast, sway-based isolation systems connect prefabricated components into a unified whole using prestressed tendons. The deformation of the contact surface fulfills the structure's requirements for inelastic deformation, providing excellent seismic resistance and self-resetting capabilities. Furthermore, prefabricated segmental double-layer steel-concrete composite piers combine the advantages of prefabricated segmental assembly and double-layer steel-concrete composite structures, exhibiting excellent mechanical properties, seismic performance, and construction convenience, including high load-bearing capacity, high stiffness, low damage, repairability, and high construction efficiency.

[0003] Combining the advantages of sliding and swaying seismic isolation methods with the multi-hazard resistance advantages of precast segmental assembly double-layer steel-concrete composite piers, this invention proposes a novel sliding-swaying segmental precast double-layer steel-concrete composite pier. By bonding PTFE plates between pier segments, a sliding layer is formed to achieve sliding seismic isolation. Furthermore, a pair of anti-convex joints are installed at the top and bottom of each pier segment to limit the relative sliding distance between segments, preventing excessive displacement of the component. The inclined surfaces of the anti-convex joints also provide a certain degree of self-resetting capability. By applying prestress, a self-resetting swaying seismic isolation system is formed between the bottom segment of the pier and the foundation. Under seismic loading, the entire pier, in conjunction with segmental sliding, achieves a combined sliding-swaying seismic isolation effect. By making full use of the limited slippage and openings between segmental joints, the piers can achieve large lateral or torsional deformation under low damage conditions, in order to adapt to the large displacement requirements caused by fault slippage, avoid excessive deformation concentration at the bottom of the piers or supports, and reduce seismic damage to bridges spanning faults. This is of great significance for seismic mitigation and disaster control of bridges in active fault areas. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a novel sliding-swing segmental prefabricated double-layer steel-concrete composite pier, particularly suitable for bridge engineering projects requiring resistance to multiple dynamic hazards (earthquakes, impacts, explosions, etc.) and prefabricated assembly construction. By combining the concept of sliding-swing synergistic seismic isolation with prefabricated segmental assembly double-layer steel-concrete composite piers, a novel sliding-swing segmental prefabricated double-layer steel-concrete composite pier is formed. This pier fully utilizes the performance advantages of composite structures, the advantages of segmental prefabrication and assembly construction, and the respective seismic isolation advantages of sliding and swing. It features outstanding resistance to dynamic loads, allows for large deformation of components, and enables rapid construction, making it particularly suitable for various needs of bridge seismic isolation and disaster control in active fault areas.

[0005] The present invention adopts the following technical solution: A sliding-rocking segmental precast double-layer steel tube concrete composite pier includes a double-layer steel tube concrete precast segment with a concave-convex joint, a PTFE plate, internal prestressing tendons, prestressing tendon anchors, a pier cap, and a cap beam. The double-layer steel-concrete precast segment with convex and concave joints includes an outer steel pipe, high-strength non-shrink concrete, and an inner steel pipe; the inner steel pipe is placed inside the outer steel pipe and is coaxially arranged with the outer steel pipe, and a convex joint and an indented joint are respectively provided at the top and bottom of the segment, which are made of the same material as the inner steel pipe; the interlayer between the outer steel pipe and the inner steel pipe is connected by filling with high-strength non-shrink concrete to form a whole segment; The angle between the inclined surfaces of the convex and concave joints of the upper and lower double-layer steel pipe concrete precast segments with convex and concave joints and the horizontal plane is the same, so that they can fit tightly when in contact with each other. The inner steel pipe at the lower end of the upper double-layer steel pipe concrete precast segment with convex and concave joints expands outward to the bottom end of the segment as an inner concave joint, while the inner steel pipe at the upper end of the lower double-layer steel pipe concrete precast segment with convex and concave joints shrinks inward from the top of the segment as an outer convex joint. A pair of PTFE plates are bonded to the top and bottom surfaces of two adjacent double-layer steel-concrete precast segments with tongue-and-groove joints to serve as a sliding layer with a low coefficient of dynamic friction, thereby achieving the effect of sliding vibration isolation. The internal prestressing tendons pass through the center of the inner steel tube into the double-layer precast steel tube concrete segments with convex and concave joints to be connected. The two ends are anchored to the abutments and cap beams at both ends of the pier by prestressing tendon anchors. By tensioning the internal prestressing tendons, axial pressure is applied to the double-layer precast steel tube concrete segments with convex and concave joints to be connected, so that the sliding layers between the double-layer precast steel tube concrete segments with convex and concave joints are tightly fitted, forming a segmental precast and assembled double-layer steel tube concrete pier. A self-resetting swaying vibration isolation system is formed between the bottom segment of the pier and the abutment.

[0006] Preferably, the PTFE plate is 2 mm thick and the coefficient of dynamic friction between the PTFE plates is 0.04.

[0007] Preferably, the angle between the inclined surfaces of the convex and concave joints and the horizontal plane is 60°, so that they can fit tightly together when in contact with each other.

[0008] Preferably, the height of the upper convex joint of the double-layer steel pipe concrete precast segment with convex and concave joints and the depth of the lower concave joint of the double-layer steel pipe concrete precast segment with convex and concave joints are both 1 / 2 of the radius length of the inner steel pipe.

[0009] Preferably, the cross-section of the double-layer steel pipe concrete precast segment with concave and convex joints is circular or rectangular.

[0010] The novel sliding-swing segmental precast double-layer steel-concrete composite pier of this invention improves the seismic performance of precast double-layer steel-concrete composite piers and enhances their deformation capacity to a certain extent, while also meeting the needs of industrialized construction. Under seismic loading, the bottom segment of the pier sways with respect to the abutment, and the segments slide against each other under the influence of the slip layer. This synergistic effect significantly reduces seismic damage to bridges. Furthermore, the misalignment, opening, or torsion of the joints coordinates with the permanent ground displacement caused by fault slippage, preventing excessive deformation concentration at the pier bottom or abutment. The sliding-swing segmental precast double-layer steel-concrete composite pier proposed in this invention shows promise for widespread application in active fault zones.

[0011] The beneficial effects of this invention are: 1. Prefabricated double-layer steel pipe concrete segmental piers can be prefabricated in the factory and transported to the site for assembly, thus meeting the requirements of industrialized construction. 2. The sliding-swing segmental precast double-layer steel pipe concrete composite pier combines the advantages of both sliding and swing seismic isolation methods, improving the bridge's ability to adapt to permanent ground displacement under fault conditions and reducing the damage to the pier under seismic action. 3. The design of the concave-convex joint provides limiting and self-resetting functions for the sliding displacement of the pier column segment. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the double-layer steel pipe concrete precast segment with concave and convex joints of the present invention.

[0013] Figure 2 This is a diagram showing the completed assembly of the sliding-swing segment prefabricated double-layer steel pipe concrete composite pier column of the present invention.

[0014] Figure 3 (a) Figure 3 (b) and Figure 3(c) is a vertical cross-section of the prefabricated double-layer steel-concrete composite pier column with sliding-swing segment of the present invention and a schematic diagram of the sliding and swing process under seismic action.

[0015] In the attached diagram: 1-Double-layer steel-concrete precast segment with convex and concave joints; 101-Outer steel pipe; 102-High-strength non-shrink concrete; 103-Inner steel pipe; 104-Outer convex joint; 105-Inner concave joint; 2-PTFE plate; 3-Internal prestressing tendons; 4-Prestressing tendon anchors; 5-Pile cap; 6-Cap beam. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 and Figure 2 As shown, the present invention provides a sliding-swing segmental prefabricated double-layer steel tube concrete composite pier column, including a double-layer steel tube concrete prefabricated segment 1 with a concave-convex joint, a PTFE plate 2, an internal prestressing tendon 3, a prestressing tendon anchor 4, a pier cap 5, and a cap beam 6. Four double-layer precast steel-concrete composite segments 1 with convex-concave joints are stacked to form the pier body. Each double-layer precast steel-concrete composite segment 1 with convex-concave joints includes an outer steel pipe 101, high-strength non-shrink concrete 102, and an inner steel pipe 103. The inner steel pipe 103 has a convex joint 104 at its top and a concave joint 105 at its bottom, both made of the same material. The angle between the inclined surfaces of the convex joint 104 and the concave joint 105 and the horizontal plane is 60°. The height of the convex joint 104 and the depth of the concave joint 105 are both half the radius of the inner steel pipe 103, allowing for a tight fit when they are in contact. The outer steel pipe 101 and the inner steel pipe 103 are connected by a layer of high-strength non-shrink concrete 102 to form a complete segment.

[0018] A pair of 2mm thick PTFE plates were bonded to the top and bottom surfaces of two adjacent double-layer steel-concrete precast sections to serve as a sliding layer with a low coefficient of dynamic friction, thereby achieving the effect of sliding vibration isolation.

[0019] The internal prestressing tendon 3 passes through the center of the inner steel pipe and passes through the double-layer steel pipe concrete precast segment to be connected. The two ends are anchored to the abutment 5 and cap beam 6 at both ends of the pier by the prestressing tendon anchor 4. The internal prestressing tendon 3 is tensioned to apply axial pressure to the double-layer steel pipe concrete precast segment to be connected, so that the sliding layer between each double-layer steel pipe concrete precast segment is tightly attached, forming a sliding-swing segment precast assembly double-layer steel pipe concrete composite pier column. The bottom segment of the pier column and the abutment 5 form a self-resetting swing vibration isolation system.

[0020] The construction method for the aforementioned sliding-swing segmental precast double-layer steel-concrete composite pier includes the following steps: Step 1: Prepare the components; Precast the pier column segments to be assembled, and prepare the prestressed tendons in advance; The pier column segment to be assembled is a double-layer steel pipe concrete precast segment with a tongue and groove joint. Step 2: On-site assembly; Step 2.1: At the construction site, anchor one end of the prestressed tendon to the bridge pier cap; Step 2.2: A pair of 2mm thick PTFE plates were glued to the top and bottom of the prefabricated pier segment respectively; Step 2.3: Pass the prestressed tendons through the center of the prefabricated pier column segments to be assembled in sequence and stack them; Step 2.4: Place the pier cap beam on the surface of the top double-layer steel tube concrete segment and fix the prestressing tendons; Step 2.5: Tension and anchor the prestressed tendons to form the sliding-swing segment precast double-layer steel pipe concrete composite pier column.

[0021] In step one, the double-layer steel-concrete composite precast segment with convex and concave joints includes an outer steel pipe, an inner steel pipe, and high-strength non-shrink concrete. The inner steel pipe is placed inside the outer steel pipe and coaxially arranged with it. A convex and a concave joint are respectively provided at the top and bottom of the segment, using the same material as the inner steel pipe. The angle between the inclined plane of the convex and concave joints and the horizontal plane is 60°. The height of the convex joint and the depth of the concave joint are both half the radius of the inner steel pipe. The interlayer between the outer and inner steel pipes is connected by filling with high-strength non-shrink concrete to form a complete segment. During the construction of step 2.2, the coefficient of dynamic friction between the segments can be reduced to 0.04 by adding a PTFE plate sliding layer between the pier segments.

[0022] The working principle of this invention is as follows: like Figure 3 As shown in (a), under normal use, the contact surfaces between the pier segments provide maximum static friction, ensuring that the pier has the horizontal stiffness and lateral force resistance to meet its functional requirements; Figure 3 As shown in (b), under seismic loading, relative slippage first occurs between the pier segments; as Figure 3As shown in (c), when the ground displacement is too large, the relative displacement between the pier segments enters the restricted range. At this time, the convex joint and the concave joint come into contact with each other, openings occur between the pier segments, the pier sways, the prestressing tendons further elongate, and the prestress level increases. Under the combined action of the prestressing tendons and the oblique concave-convex joint surfaces, the pier segments have a tendency to self-recover and eventually return to their original position. In addition, when the fault causes the bridge torsion, the joints between the pier segments can also release the torsion to reduce the damage to the bridge under seismic action.

[0023] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications and substitutions are all included within the scope defined by the claims of this application.

Claims

1. A sliding-rocking segmental precast double-layer steel-concrete composite pier, characterized in that: Includes double-layer precast steel-concrete composite segments with tongue and groove joints, PTFE sheets, internal prestressing tendons, prestressing tendon anchors, pile caps and cap beams; The double-layer steel-concrete precast segment with convex and concave joints includes an outer steel pipe, high-strength non-shrink concrete, and an inner steel pipe; the inner steel pipe is placed inside the outer steel pipe and is coaxially arranged with the outer steel pipe, and a convex joint and an indented joint are respectively provided at the top and bottom of the segment, which are made of the same material as the inner steel pipe; the interlayer between the outer steel pipe and the inner steel pipe is connected by filling with high-strength non-shrink concrete to form a whole segment; The angle between the inclined surfaces of the convex and concave joints of the upper and lower double-layer steel pipe concrete precast segments with convex and concave joints and the horizontal plane is the same, so that they can fit tightly when they come into contact with each other. The inner steel pipe diameter at the lower end of the upper double-layer steel pipe concrete precast segment with convex and concave joints expands outward to the bottom end of the segment as an inner concave joint, and the inner steel pipe at the upper end of the lower double-layer steel pipe concrete precast segment with convex and concave joints shrinks inward from the top of the segment as an outer convex joint. A pair of PTFE plates are bonded to the top and bottom surfaces of two adjacent double-layer steel pipe concrete precast segments with tongue and groove joints, serving as a slip layer with a low coefficient of dynamic friction. The internal prestressing tendons pass through the center of the inner steel tube into the double-layer precast steel tube concrete segments with convex and concave joints to be connected. The two ends are anchored to the abutments and cap beams at both ends of the pier by prestressing tendon anchors. By tensioning the internal prestressing tendons, axial pressure is applied to the double-layer precast steel tube concrete segments with convex and concave joints to be connected, so that the sliding layers between the double-layer precast steel tube concrete segments with convex and concave joints are tightly fitted, forming a segmental precast and assembled double-layer steel tube concrete pier. A self-resetting swaying vibration isolation system is formed between the bottom segment of the pier and the abutment.

2. The sliding-swing segmental precast double-layer steel-concrete composite pier column according to claim 1, characterized in that: The PTFE plate is 2mm thick, and the coefficient of dynamic friction between the PTFE plates is 0.

04.

3. The sliding-swing segmental precast double-layer steel-concrete composite pier column according to claim 2, characterized in that: The angle between the inclined surface of the convex joint and the concave joint and the horizontal plane is 60°, which allows them to fit tightly together when in contact.

4. The sliding-swing segmental precast double-layer steel-concrete composite pier column according to claim 3, characterized in that: The height of the upper convex joint of the double-layer steel pipe concrete precast segment with convex and concave joints and the depth of the lower concave joint of the double-layer steel pipe concrete precast segment with convex and concave joints are both 1 / 2 of the inner steel pipe radius length.

5. The sliding-swing segmental precast double-layer steel-concrete composite pier column according to claim 4, characterized in that: The cross-section of the double-layer steel pipe concrete precast segment with concave and convex joints is circular or rectangular.

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