Fabricated prefabricated segment assembled hollow steel tube-concrete pier and method

Abstract

The invention relates to the field of bridge engineering, in particular to an assembly type prefabricated segment assembled hollow steel tube-concrete pier and a method, the pier comprises a bearing platform, a cover beam, a prefabricated pier column, prestressed tendons and energy dissipation steel bars, the prestressed tendons are connected with the bearing platform, the prefabricated pier column and the cover beam in a penetrating mode from bottom to top along the axis to form a whole; the prefabricated pier column is divided into a top section, a middle section and a bottom section. The top section and the middle section all adopt reinforced concrete hollow sections, and longitudinal bars are discontinuous at joints. The bottom section is divided into a core area and a peripheral area, the core area adopts a hollow interlayer steel pipe concrete section, and the inner diameter of the core area is consistent with that of the upper section; and after energy dissipation steel bars are arranged between the core area and the peripheral area, grouting materials are poured, so that the outer diameter of the bottom section is kept consistent with that of the upper section. The two ends of the energy dissipation steel bar are mechanically connected with the bearing platform and the anchoring steel bar embedded in the middle section correspondingly, and the built-in energy dissipation steel bar can be replaced after an earthquake. The pier has the advantages that the section is low in damage after an earthquake, the built-in energy dissipation steel bars can be replaced, economic benefits are remarkable and the like, and the anti-seismic toughness of the bridge can be improved.

Description

Technical Field

[0001] The invention relates to the field of bridge engineering, and in particular to an assembled prefabricated segment assembly of a hollow steel pipe-concrete bridge pier and a method thereof. Background Art

[0002] The damage of bridges in earthquakes not only causes casualties and economic losses, but also affects emergency rescue and post-disaster reconstruction. With the increasing emphasis on post-earthquake rescue and safety, bridges are required to have the function of rapid post-earthquake recovery. Therefore, developing a new type of post-earthquake recoverable bridge structure system and improving earthquake resistance are of great significance to promoting the construction of resilient cities.

[0003] Prefabricated segmental piers use prefabrication and assembly technology, and prefabricated segments are connected by prestressed tendons. They have good self-reset capabilities and are an effective way to achieve the concept of rapid bridge construction and post-earthquake recovery. However, the plastic hinge area of ​​the bottom segment of prefabricated segmental piers is easily damaged, the built-in energy-absorbing components are difficult to replace, and the seismic design method is imperfect, so their application in high seismic intensity areas is severely limited. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an assembled prefabricated segment assembly hollow steel pipe-concrete pier and method to solve the problems of serious damage to the plastic hinge area of ​​the bottom segment of the existing prefabricated segment assembly piers, poor durability of external energy-absorbing components and difficulty in replacing internal energy-absorbing components.

[0005] One of the purposes of the present invention is to provide an assembled prefabricated segmented hollow steel tube-concrete pier, a cap beam, a prefabricated pier column, a pedestal, prestressed tendons and an energy-absorbing steel rod; the prefabricated pier column includes a top segment, an intermediate segment and a bottom segment core area, which are prefabricated in segments; the top segment and the intermediate segment are hollow sections of reinforced concrete; threaded anchor steel bars are embedded in the bottom surface of the intermediate segment; the bottom segment is divided into a bottom segment core area and a peripheral area; the bottom segment core area is a hollow sandwich steel tube concrete section, including coaxially nested inner and outer steel tubes, and concrete is poured between the interlayers to form a composite force-bearing structure; a peripheral area is provided around the core area of ​​the bottom segment formed by pouring grouting material; the two ends of the energy-absorbing steel rod are respectively connected to the anchor steel bars embedded in the pedestal and the intermediate segment through mechanical connection joints; a corrugated pipe coaxial with the top segment is reserved in the cap beam, and the prestressed tendons run through the corrugated pipes of the pedestal, prefabricated pier column and the cap beam, and are anchored by anchors to form an integral structure.

[0006] Furthermore, the prefabricated pier column includes a bottom segment, a middle segment and a plurality of top segments; the height of the bottom segment is at least 1.5D, D is the outer diameter of the cross section, and the number of top segments is adjusted according to the pier height and the cross section size.

[0007] Furthermore, the inner diameter and axial compressive bearing capacity of the hollow sandwich steel tube concrete section in the core area of ​​the bottom segment are consistent with those of the hollow section of the upper segment.

[0008] Furthermore, the foundation is pre-embedded with anchor steel bars extending upward, and the longitudinal bars of the middle segment extend downward to form anchor steel bars, and threaded connection joints are provided at the ends; the anchor steel bars are axially colinear with the energy-absorbing steel rods and are connected at the joints through mechanical joints.

[0009] Furthermore, the hollow part of each segment is coaxially connected with the inner steel pipe of the bottom segment to form a continuous prestressed tendon bundle passage.

[0010] Furthermore, the hollow cross section is circular, rectangular, elliptical or rounded.

[0011] Furthermore, the prestressed tendons are steel strands or fiber reinforced tendons.

[0012] Furthermore, the energy dissipation steel rods are hot-rolled ribbed steel bars, stainless steel rods, energy dissipation steel plates, buckling restrained braces or dampers.

[0013] The invention also discloses a construction method of the bridge pier, comprising the following steps: S1. Factory prefabrication: prefabricate the cap beam, top segment, middle segment and bottom segment core area; concentrically position the inner and outer steel pipes and then pour the sandwich concrete to form the bottom segment core area; prefabricate the anchor steel bars with threaded joints on the bottom surface of the middle segment; reserve longitudinal corrugated pipes in the cap beam; S2. Construction of the cap: pre-embed anchor steel bars with threaded joints and set prestressed tendons, with the joints exposed on the top surface; the prestressed tendons pass through the corrugated pipe holes of the cap and are fixed; S3, pier assembly: align the core area of ​​the bottom segment and the cap, connect the energy-absorbing steel rod and the threaded joint; assemble the middle segment and the top segment in sequence to keep them coaxial, and pour the grouting material in the peripheral area; S4. Cap beam anchoring: After the cap beam is installed in place, the prestressed tendons are inserted and anchored by post-tensioning method to form an integral structure.

[0014] The present invention has the following advantages and beneficial effects: 1. Make full use of the advantages of good self-reset ability of prefabricated segmented piers and the characteristics of light weight, high strength and good ductility of hollow sandwich steel tube concrete components. Under the action of earthquake, the main structure of the pier (including the core area of ​​the bottom segment and other upper segments) can be kept basically intact, achieving low damage to the pier after the earthquake.

[0015] 2. Under the action of earthquake, the prestressed tendons maintain elasticity and provide self-reset capability, allowing the peripheral area of ​​the bottom segment and the energy-absorbing steel rod to produce elastic-plastic deformation, provide energy-absorbing capacity, realize the coordinated work of the self-reset elements and energy-absorbing elements of the pier, and reduce the residual deformation of the pier after the earthquake.

[0016] 3. The bottom segment of the pier is pre-set with a core area and a peripheral area. After the earthquake, the mechanically connected energy-absorbing steel rods are replaced and the peripheral area is repaired, so that the earthquake-damaged components of the pier, i.e., the built-in energy-absorbing steel rods, can be quickly replaced, providing a feasible solution for the post-earthquake repair of prefabricated segment-assembled piers.

[0017] 4. Prefabricated piers can fully utilize the good seismic performance advantages of hollow sandwich steel tube concrete components and reduce the damage to the bottom segment by mixing hollow sandwich steel tube concrete components and reinforced concrete hollow components, while reducing construction costs and improving economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the bridge pier of the present invention; Figure 2 for Figure 1 Schematic diagram of reinforcement of cross section AA of the bottom segment of the middle precast pier column; Figure 3 for Figure 1 Schematic diagram of reinforcement arrangement of the cross section BB of the middle segment of the precast pier column; Figure 4 for Figure 1 Schematic diagram of reinforcement arrangement of CC cross section of the top segment of the middle precast pier column; In the figure: 1—cap beam; 2—precast pier; 3—top segment; 4—middle segment; 5—bottom segment; 6—cap; 7—prestressed tendons; 8—energy-absorbing steel rods; 9—inner steel pipe; 10—sandwich concrete; 11—outer steel pipe; 12—core area of ​​bottom segment; 13—peripheral area; 14—anchor steel bars; 15—connecting joints; 16—prestressed anchor; 17—corrugated pipe channel; 18—longitudinal bars; 19—hoops; 20—concrete; 21—tension bars. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] like Figures 1 to 4 As shown, this embodiment discloses an assembled prefabricated segmented hollow steel tube-concrete bridge pier, including a cap beam 1, a prefabricated pier column 2, a cap 6, prestressed tendons 7 and energy-absorbing steel rods 8. The prefabricated pier column 2 is prefabricated in sections by a top segment 3, an intermediate segment 4 and a bottom segment core area 12, and each segment is connected by mechanical connection and prestressed tendons 7 to form an integral structure.

[0021] The prefabricated pier 2 includes a top segment 3, an intermediate segment 4 and a bottom segment core area 12; the top segment 3 is a reinforced concrete hollow section; the intermediate segment 4 is also a reinforced concrete hollow section, with threaded anchor steel bars 14 embedded in the bottom surface for connection with the energy-absorbing steel rod 8; the hollow parts of the top segment 3 and the intermediate segment 4 are coaxially connected to the inner steel pipe 9 of the bottom segment core area 12 to form a continuous bundle passage for the prestressed tendons 7.

[0022] The bottom segment 5 is divided into a bottom segment core area 12 and a peripheral area 13; the bottom segment core area 12 is a hollow sandwich steel tube concrete section, consisting of a coaxially nested inner steel tube 9 and an outer steel tube 11, with a sandwich concrete 10 poured between the two to form a composite force-bearing structure; the peripheral area 13 is formed by pouring grouting material, surrounding the bottom segment core area 12 to enhance structural stability.

[0023] The prefabricated pier column 2 includes a bottom segment 5, an intermediate segment 4 and a plurality of top segments 3; the segment height of the bottom segment 5 is at least 1.5D, where D is the outer diameter of the cross section. In order to meet the steel pipe constraint requirements and prevent the segment damage range from extending to the upper segment, the number of top segments 3 is changed accordingly according to the actual pier height and pier cross-sectional dimensions of the project.

[0024] The two ends of the energy dissipation steel rod 8 are connected to the anchoring steel bars 14 embedded in the pedestal 6 and the middle segment 4 respectively by mechanical connection joints 15, so as to form a through energy dissipation connection system for dissipating earthquake energy.

[0025] A corrugated pipe 17 coaxial with the top segment 3 is reserved in the cap beam 1. The prestressed tendons 7 penetrate the corrugated pipe 17 of the pedestal 6, the prefabricated pier 2 and the cap beam 1, and are anchored in the cap beam 1 by the anchor 16, connecting the entire structure as a whole.

[0026] Preferably, the hollow cross-section of the prefabricated pier 2 can be circular, rectangular, elliptical or round-end shaped, and the specific form is determined according to engineering requirements.

[0027] Preferably, the prestressed tendons 7 may be made of steel strands or fiber reinforced tendons; the energy dissipation steel bars 8 may be made of hot-rolled ribbed steel bars, stainless steel bars, energy dissipation steel plates, buckling restrained braces or dampers.

[0028] The present invention also discloses a method for manufacturing a prefabricated segment-assembled hollow steel pipe-concrete mixed structure bridge pier with replaceable energy-consuming parts, comprising the following steps: S1. Prefabricate reinforced concrete cap beam 1, top segment 3, middle segment 4 and bottom segment core area 12 in the factory. Position the inner steel pipe 9 and the outer steel pipe 11 to ensure that their cross-section centers coincide, and pour the sandwich concrete 10 between the inner steel pipe 9 and the outer steel pipe 11 to form the bottom segment core area 12; tie the steel cages of the reinforced concrete top segment 3 and the middle segment 4, select part of the longitudinal reinforcement 18 of the middle segment 4 to reserve threaded connection joints 15 downward as anchor reinforcement 14, and pour concrete to expose the joints 15 reserved for energy-absorbing steel bars on the bottom surface of the middle segment 4; tie the steel cages of the reinforced concrete cap beam 1, reserve corrugated pipes 17 along the longitudinal axis of the cap beam 1, and pour the cap beam 1 concrete; after completing the prefabrication work, transport all prefabricated components to the site.

[0029] S2. Fabricate the reinforced concrete cap 6 on site: tie the steel cage of the reinforced concrete cap 6, embed anchoring steel bars 14 in the cap 6, reserve threaded connection joints 15 upward from the anchoring steel bars 14, pour the concrete of the cap 6 so that the joints 15 reserved for the energy-absorbing steel bars are exposed on the top surface of the cap 6; the prestressed tendons 7 pass through the pre-embedded corrugated pipe channels 17 of the cap, and are fixed in the reserved grooves of the cap 6 by anchors 16.

[0030] S3. Assemble the top segment 3, middle segment 4 and bottom segment 5 of the prefabricated pier 2 on site. Assemble the bottom segment core area 12 on the top surface of the pedestal 6, pass the prestressed tendon 7 through the center of the bottom segment core area 12, and accurately position the pedestal 6 and the bottom segment core area 12 to be coaxial; screw the energy-absorbing steel rods 8 into the sleeves of the joints 15 on the top surface of the pedestal 6, so that the lower ends of the energy-absorbing steel rods 8 establish a mechanical connection with the joints 15 reserved on the top surface of the pedestal 6; assemble the bottom surface of the middle segment 4 on the top surface of the bottom segment core area 12, pass the prestressed tendon 7 through the hollow part of the middle segment 4, and accurately position the middle segment 4 and the bottom segment core area 12 to be coaxial; reversely screw the energy-absorbing steel rods 8 into the sleeves of the joints 15 on the top surface of the pedestal 6, so that the lower ends of the energy-absorbing steel rods 8 establish a mechanical connection with the joints 15 reserved on the top surface of the pedestal 6; assemble the bottom surface of the middle segment 4 on the top surface of the bottom segment core area 12, pass the prestressed tendon 7 through the hollow part of the middle segment 4, and accurately position the energy-absorbing steel rods 8 and the bottom segment core area 12 to be coaxial; reversely screw the energy-absorbing steel rods 8 into the sleeves of the joints 15 on the top surface of the pedestal 6, so that the energy-absorbing steel rods 8 and the joints 15 reserved on the top surface of the pedestal 6 are mechanically connected; reversely screw the energy-absorbing steel rods 8 into the sleeves of the joints 15 on the top surface of the pedestal 6, so that the energy-absorbing steel The joint 15 sleeve of the middle segment 4 establishes a mechanical connection between the upper end of the energy-absorbing steel rod 8 and the joint 15 reserved on the bottom surface of the middle segment 4; the bottom surface of the top segment 3 is assembled on the top surface of the middle segment 4, and the prestressed tendon 7 passes through the hollow part of the top segment 3, and is precisely positioned to ensure that the top segment 3 and the middle segment 4 are longitudinally coaxial; after the bottom segment core area 12 and the energy-absorbing steel rod 8, the middle segment 4, and the top segment 3 are all installed, a circular formwork is supported and grouting material is poured around the outer periphery of the bottom segment core area 12 to form a peripheral area 13, completing the assembly of the prefabricated pier 2.

[0031] S4. Assemble the reinforced concrete cap beam 1 and anchor the prestressed tendons 7. Assemble the cap beam 1 above the top surface of the last pier body top segment 3, ensuring that the pre-buried corrugated pipe channel 17 of the cap beam 1 and the pre-buried corrugated pipe channel 17 of the pedestal 6 are longitudinally coaxial; after passing the prestressed tendons 7 through the corrugated pipe channel 17 reserved in the cap beam 1, use the post-tensioning method to tension the prestressed tendons 7 and anchor them in the cap beam 1, thereby connecting the pedestal 6, the prefabricated pier column 2 and the cap beam 1 as a whole.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention can still modify the technical solutions recorded in the above embodiments, or replace part or all of the technical features therein with equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An assembled prefabricated segmented hollow steel pipe-concrete bridge pier, characterized in that: It comprises a cap beam (1), a prefabricated pier column (2), a cap (6), prestressed tendons (7) and an energy-absorbing steel rod (8); The prefabricated pier column (2) comprises a top segment (3), an intermediate segment (4) and a bottom segment core area (12) which are prefabricated in sections; the top segment (3) and the intermediate segment (4) are hollow reinforced concrete sections; a threaded anchoring steel bar (14) is pre-embedded in the bottom surface of the intermediate segment (4); the bottom segment (5) is divided into a bottom segment core area (12) and a peripheral area (13); the bottom segment core area (12) is a hollow sandwich steel tube concrete section, comprising a coaxially nested inner steel tube (9) and an outer steel tube (11), and a sandwich concrete (10) is poured between the inner steel tube (9) and the outer steel tube (11) to form a composite load-bearing structure; a peripheral area (13) formed by pouring grouting material is provided outside the bottom segment core area (12); Both ends of the energy-absorbing steel rod (8) are connected to the anchoring steel bars (14) pre-buried in the cap and the middle segment respectively by means of mechanical connection joints (15); A corrugated pipe (17) coaxial with the top segment (3) is reserved in the cap beam (1), and the prestressed tendons (7) penetrate the corrugated pipe (17) of the cap platform (6), the prefabricated pier column (2) and the cap beam (1), and are anchored in the cap beam (1) by means of anchors (16), thereby connecting the cap platform (6), the prefabricated pier column (2) and the cap beam (1) into a whole.

2. The prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1, characterized in that: The prefabricated pier column (2) comprises a bottom segment (5), an intermediate segment (4) and a plurality of top segments (3); the segment height of the bottom segment (5) is at least 1.5D, where D is the outer diameter of the cross section.

3. The assembled prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1, characterized in that: The inner diameter and axial compressive bearing capacity of the hollow sandwich steel tube concrete section of the core area (12) of the bottom segment (5) are consistent with those of the reinforced concrete hollow sections of the middle segment (4) and the top segment (3).

4. The assembled prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1 is characterized by: The cap (6) is pre-embedded with anchoring steel bars (14) extending upwards, and part of the longitudinal bars (18) of the middle segment (4) extend downwards to form anchoring steel bars (14), the ends of which are provided with threaded connection joints (15); the anchoring steel bars (14) and the energy-absorbing steel bars (8) are axially colinear, and the anchoring steel bars (14) and the energy-absorbing steel bars (8) are connected through the upper and lower joints of the bottom segment (5) using mechanical connection joints (15).

5. The assembled prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1 is characterized by: The hollow parts of the top segment (3) and the middle segment (4) are coaxially connected to the inner steel pipe (9) of the core area (12) of the bottom segment, forming a continuous bundle passage for the prestressed tendons (7).

6. The assembled prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1 is characterized by: The hollow cross-section of the prefabricated pier (2) may be circular, rectangular, elliptical or round-end shaped.

7. The assembled prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1 is characterized by: The prestressed tendons (7) may be steel strands or fiber reinforced tendons.

8. The assembled prefabricated segmented hollow steel pipe-concrete bridge pier according to claim 1 is characterized by: The energy dissipation steel bar (8) may be a hot-rolled ribbed steel bar, a stainless steel bar, an energy dissipation steel plate, a buckling restraint brace or a damper.

9. The construction method of prefabricated segmented hollow steel pipe-concrete bridge pier according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Factory prefabrication: prefabricate the cap beam (1), the top segment (3), the middle segment (4) and the bottom segment core area (12); cast the sandwich concrete to form the bottom segment core area (12) by concentrically positioning the inner and outer steel pipes (9, 11); prefabricate anchor steel bars (14) with threaded joints on the bottom surface of the middle segment (4); and reserve a longitudinal corrugated pipe (17) in the cap beam (1); S2, construction of the cap: pre-embed anchor steel bars (14) with threaded joints and arrange prestressed tendons (7) so that the joints (15) are exposed on the top surface of the cap (6); the prestressed tendons (7) pass through the pre-embedded corrugated pipe channel (17) of the cap and are fixed in the reserved groove of the cap (6) by means of anchors (16); S3, pier assembly: after aligning the bottom segment core area (12) with the pedestal (6) axis, connect the pedestal (6) and the threaded joint (15) of the middle segment (4) through the energy-absorbing steel rod (8); assemble the middle segment (4) and the top segment (3) in sequence and keep them longitudinally coaxial, and finally pour the grouting material of the outer area (13); S4. Cap beam anchoring: After the cap beam (1) and the top segment (3) are aligned and installed, the prestressed tendons (7) are inserted for post-tensioning anchoring to form an integral connection structure of the cap (6), the pier column (2) and the cap beam (1).

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