Reinforcing structure for transforming bridge pier by using existing bridge abutment

Abstract

The utility model discloses a reinforcing structure for transforming a pier by using an existing bridge abutment, belongs to the field of bridge engineering, and solves the problems of high construction difficulty and large workload in the existing transformation method. A bridge abutment body is dismantled, a heightened reinforcing bearing platform with one lengthened side is arranged in the middle of an existing bridge abutment, a newly-added pile foundation is arranged at the bottom of the lengthened position of the reinforcing bearing platform, and a newly-built pier body is arranged at the top of the reinforcing bearing platform. Compared with a traditional transformation method, the bridge abutment structure has the advantages that the existing bridge abutment structure is fully utilized, waste caused by large disassembly and large construction is avoided, and social resources are saved. By reinforcing and transforming the existing abutment foundation, the construction difficulty and risk are reduced, the construction period is shortened, and traffic can be opened as soon as possible.

Description

Technical Field

[0001] This utility model belongs to the field of bridge engineering, specifically relating to a reinforcement structure that utilizes existing bridge abutments to modify bridge piers. Background Technology

[0002] With the rapid development of the national economy and urban construction, the transportation system has also entered a period of great development. In the process of bridge renovation for urban planning, old city renovation, and transportation upgrading, we often encounter bridges that have been in use for a short time and are in good condition, or bridges with special functions that are not suitable for demolition. These bridges need to be extended and lengthened, which involves the work of converting existing bridge abutments into bridge piers.

[0003] The technical approaches to converting existing bridge abutments into bridge piers generally fall into two categories. First, demolishing the existing abutment body and pier cap, and constructing new piers on the original abutment site. The disadvantages of this approach are: due to the special nature of bridge abutment foundations, the demolition work is enormous; the foundation pit support required for pier cap demolition is difficult; new pier caps require piling at the original pile locations, which is challenging, slows down the drilling process, and the existing pile foundations can affect the bearing capacity of the new piles. Second, demolishing the existing abutment body, and constructing new piers on both sides of the existing abutment. The disadvantages of this approach are: the centerline of the new piers does not coincide with the branch line of the superstructure, requiring corresponding modifications to the superstructure, or the use of large eccentric piers, which is difficult to construct; the construction period for the substructure is long, which is not conducive to opening the road to traffic as soon as possible.

[0004] Against this backdrop, a reinforcement structure for bridge piers by utilizing existing bridge abutments is proposed. By reinforcing and modifying existing bridge abutments, the bridge structure can be reused, saving construction time and investment, and thus achieving objective economic benefits. Utility Model Content

[0005] The purpose of this utility model is to provide a reinforcement structure for modifying bridge piers using existing bridge abutments, so as to solve the problems of high construction difficulty and large workload in existing modification methods.

[0006] The technical solution of this utility model is: a reinforcement structure for modifying bridge piers using existing bridge abutments. The existing bridge abutment includes existing pile foundations, existing abutments and abutment bodies arranged sequentially from bottom to top. The abutment bodies are demolished, and a reinforced abutment with increased height and extended length on one side (along the longitudinal direction of the bridge) is provided in the middle of the existing bridge abutment. New pile foundations are provided at the bottom of the extended part of the reinforced abutment, and a new pier body is provided at the top of the reinforced abutment.

[0007] As a further improvement of this utility model, roughened surfaces are provided on the top and side surfaces of the connection between the existing bridge abutment and the reinforced bearing platform.

[0008] As a further improvement of this utility model, the connection between the reinforced foundation and the existing foundation is provided with vertical reinforcement bars and horizontal reinforcement bars.

[0009] As a further improvement of this utility model, vertical reinforcement bars are installed between the newly built pier body and the reinforced foundation, and between the existing foundation and the pier body.

[0010] As a further improvement of this utility model, prestressed tendons are provided along the longitudinal direction of the bridge in the reinforced pier and the existing pier.

[0011] The beneficial effects of this utility model are as follows: Compared with traditional renovation methods, this utility model makes full use of the existing bridge abutment structure, avoids the waste caused by large-scale demolition and construction, and saves social resources. By reinforcing and renovating the existing bridge abutment foundation, this utility model reduces construction difficulty and risks, saves construction time, and facilitates the early opening of the bridge to traffic. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the elevation structure of this utility model;

[0013] Figure 2 This is a side view of the present invention.

[0014] Figure 3 This is a schematic diagram of the planar structure of the present invention;

[0015] Figure 4 This is a schematic diagram of the interior of the facade of this utility model;

[0016] Figure 5 This is a side internal view of the present invention;

[0017] Figure 6 This is a planar internal schematic diagram of the present invention.

[0018] In the diagram: 100, existing pile cap; 200, existing pile foundation; 300, abutment body; 1, reinforced pile cap; 2, new pile foundation; 3, newly built pier body; 4, roughened surface; 5, vertical reinforcement of pile cap; 6, horizontal reinforcement of pile cap; 7, vertical reinforcement of pier body; 8, prestressed tendons. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings.

[0020] like Figure 1-6 As shown, a reinforcement structure for modifying bridge piers using existing bridge abutments is described. The existing bridge abutment includes existing pile foundations 200, existing abutment 100, and abutment body 300 arranged sequentially from bottom to top. The abutment body 300 is demolished, and a reinforced abutment 1 with increased height and extended on one side (along the longitudinal direction of the bridge) is provided in the middle of the existing bridge abutment 100. A new pile foundation 2 is provided at the bottom of the extended part of the reinforced abutment 1, and a new pier body 3 is provided at the top of the reinforced abutment 1.

[0021] A roughened surface 4 is provided on the top and side surfaces of the existing bridge abutment 100 and the reinforced bearing 1 respectively.

[0022] The connection between the reinforced foundation 1 and the existing foundation 100 is provided with vertical reinforcement bars 5 and horizontal reinforcement bars 6.

[0023] Vertical reinforcement bars 7 are installed between the newly built pier body 3, the reinforced foundation 1, and the existing foundation 100.

[0024] Prestressed tendons 8 are installed along the longitudinal direction of the bridge within the reinforced pier 1 and the existing pier 100.

[0025] Example 1

[0026] The existing pier cap 100 is 2.0m thick and has 8 existing piles 200 with a diameter of 1.2m. The pile spacing is 3.2m along the bridge direction and 6-8.5m across the bridge direction. Due to the significant increase in vertical support reaction force after the pier renovation and the insufficient reinforcement of the existing pier cap 100, it is difficult to meet the stress requirements of the pier. Therefore, a new pile 2 is set on the high-mileage side of the abutment, the abutment body 300 is demolished, and the reinforced pier cap 1 and the existing pier cap 100 are connected into a whole by rebar installation and welding of reinforcing steel bars.

[0027] The reinforcement of pier cap 1 achieves foundation strengthening by raising and lengthening (along the longitudinal direction of the bridge) the existing pier cap 100. After the renovation, the existing pier cap 100 is raised by 1.0m and lengthened (along the longitudinal direction of the bridge) by 3.2m, and the width of reinforced pier cap 1 (along the transverse direction of the bridge) is 10.7m. Before the renovation, the abutment body 300 is first removed, and then the top surface and the sides requiring renovation of the existing pier cap 100 are roughened to form a roughened surface 4 with regular texture and uniform depth. After the roughened surface 4 is formed, the surface powder is cleaned off with a wire brush and water to improve the adhesion between the new and old concrete.

[0028] After the surface roughening process 4 is completed, rebar installation is carried out. The reinforced foundation 1 is connected to the existing foundation 100 through vertical rebar installation 5 and horizontal rebar installation 6. The vertical rebar installation 5 uses 28mm diameter HRB400 steel bars and is arranged on the top surface of the existing foundation 100 in a quincunx pattern, spaced 10-40cm apart, forming a dense distribution at the edges and sparse distribution in the center; the vertical rebar installation 5 should be inserted into the existing foundation 100 for no less than 90cm, and the pull-out force of a single bar should not be less than 110kN. The horizontal rebar installation 6 uses 20mm diameter HRB400 steel bars and is arranged on the side of the existing foundation 100, inserted along the edge of the interface between the new and old concrete, spaced 10-20cm apart, with an insertion depth of no less than 40cm, and the pull-out force of a single bar should not be less than 60kN.

[0029] The newly constructed pier 3 is connected to the reinforced foundation 1 and the existing foundation 100 via vertical reinforcing bars 7. The vertical reinforcing bars 7 are made of 28mm diameter HRB400 steel bars, arranged along the edge of the newly constructed pier 3, with the position and quantity consistent with the main reinforcing bars of the newly constructed pier 3. The bars are inserted into the existing foundation 100 for no less than 90cm, and the pull-out force of a single bar is no less than 110kN.

[0030] The adhesives used for vertical rebar anchoring (5) of the foundation cap, horizontal rebar anchoring (6) of the foundation cap, and vertical rebar anchoring (7) of the pier body should be modified epoxy structural adhesives, specifically Grade A adhesives. The hole depth for the rebar anchoring should be the same as the anchoring depth, and the hole diameter should be 4mm larger than the rebar anchoring depth. A pull-out test is required for the rebar anchoring, with a sampling rate of no less than 5%. The other end of the anchored rebar is tied and welded to the connected structural rebar to form a rebar skeleton, before the foundation cap (1) and the newly constructed pier body (3) are reinforced.

[0031] To address the insufficient punching shear capacity of the existing pile caps due to their large spacing (200mm), and to enhance the bond strength and force transfer efficiency between the new and old pile cap concrete, prestressed tendons 8 were installed along the longitudinal direction of the bridge within both the reinforced pile cap 1 and the existing pile cap 100. The prestressed tendons 8 were positioned 0.75m from the bottom of the existing pile cap 100, spaced 1.5m apart along the transverse direction, for a total of 7 tendons, using small drill holes. The prestressed tendons were constructed using 5-Φs15.2 high-strength, low-relaxation steel strands, with an anchorage control stress of 1395 MPa. The steel strands were sheathed in 55mm inner diameter corrugated metal tubing. After the reinforced pile cap 1 concrete was cured to a strength and elastic modulus of not less than 90% of the design values, the prestressed tendons 8 were tensioned. Tensioning was performed using a dual control approach, prioritizing tension force and verifying elongation. After the prestressed tendons are tensioned, their corrugated pipes are vacuum grouted. Before grouting, the pipes are cleaned with pressurized water and dried with compressed air. The grouting must be dense. Grouting should be carried out within 24 hours after the prestressed tendons are tensioned to prevent the steel wires from rusting.

[0032] After the above work is completed, construction of the new pier 3 will commence. The new pier 3 is a double-column frame pier with a cross-sectional dimension of 2.6 × 1.4 m and a corner radius R = 20 cm; a tie beam will be installed at the top of the pier.

[0033] This utility model provides a new renovation solution that extends and lengthens bridges with special functions that are not suitable for demolition, adding new technical options. By reinforcing and utilizing the existing bridge abutment foundations, it overcomes the huge waste caused by demolition and reconstruction, saves construction time, and plays an important role in promoting the development of bridge construction technology.

Claims

1. A reinforcing structure for reconstructing a pier by using an existing abutment, the existing abutment comprising an existing pile foundation, an existing pile cap and an abutment body which are sequentially arranged from bottom to top, characterized in that: Dismantle the pier body (300), set the reinforced pile cap (1) with heightening and one side lengthening in the middle of the existing pile cap (100), set the new pile foundation (2) at the bottom of the lengthened part of the reinforced pile cap (1), and set the newly-built pier body (3) at the top of the reinforced pile cap (1).

2. The reinforcing structure for reconstructing a pier using an existing abutment according to claim 1, wherein: The top surface and the side surface of the existing pile cap (100) connected with the reinforced pile cap (1) are respectively provided with the chiseled surface (4).

3. The reinforcing structure for transforming a pier by using an existing abutment according to claim 1 or 2, characterized in that: The connection part of the reinforced pile cap (1) and the existing pile cap (100) is provided with the pile cap vertical planting bar (5) and the pile cap transverse planting bar (6).

4. The reinforcing structure for reconstructing a pier using an existing abutment according to claim 3, wherein: The pier body vertical planting bar (7) is arranged between the newly-built pier body (3) and the reinforced pile cap (1) and the existing pile cap (100).

5. The reinforcing structure for reconstructing a pier using an existing abutment according to claim 4, wherein: The pre-stressed beam (8) is arranged in the longitudinal bridge direction in the reinforced pile cap (1) and the existing pile cap (100).

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