Method of strengthening arch bridge

Abstract

FIELD: bridge construction.SUBSTANCE: invention can be used in the repair and strengthening of existing arched reinforced concrete bridges. Each arch of the bridge consists of two half-arches, which rest on supports; the beams rest at one end on the supports and at the other on the half-arches. First, the road surface is removed and the bridge elements are cleaned. The bridge's shore supports are strengthened by installing ground anchors in combination with a monolithic anchor block, and the bridge's semi-arches are strengthened by connecting two semi-arches adjacent to the support with the beams lying on them. First, the road surface is removed and the bridge elements are cleaned. The bridge's shore supports are then strengthened by installing ground anchors in combination with a monolithic anchor block. After which the bridge semi-arches are strengthened by joining two semi-arches adjacent to the support with beams resting on them. Two beams adjacent to the support and the support are first connected with prestressed high-strength strands, which are secured with anchors on the half-arches on which the ends of the beams rest, forming the first lower tier of strands. Then, two semi-arches adjacent to the support, two beams and the support are connected with pre-stressed high-strength strands, which are secured with anchors on opposite sides of the semi-arches, forming a second upper tier, with the strands in both tiers being pulled through the inter-beam space, which is then concreted with fibre-reinforced concrete, then hinged support parts are installed at the points where the semi-arches rest on the bridge supports, and the resulting arched-cantilever T-shaped structure is concreted with fibre-reinforced concrete. In the areas of the tops of the arches, expansion joints are installed and the road surface is laid.EFFECT: restoration and strengthening of the load-bearing capacity of the arch bridge while maintaining its geometry.1 cl, 2 dwg

Description

[0001] The proposed invention relates to bridge construction and can be used in the repair and strengthening of existing arch bridges in operation.

[0002] Old arch bridges, over many years of operation, face problems that require solutions to improve the reliability and durability of their structures. These problems can be related to the arch design, wear and tear of building materials, and operating conditions, such as natural wear and tear of materials, leading to reduced strength; damaged waterproofing, leading to corrosion of materials and mortar washout; thermal deformations, leading to cracks; and changes in loads, increasing the stress on the arches.

[0003] Various technologies are currently used to strengthen old arch bridges, for example:

[0004] - increasing the height and width of the ribs with the addition of reinforcement, the installation of an overlay plate included in the joint work with the ribs.

[0005] - installation of steel or composite reinforcement belts around the perimeter of the arch, which take on the spacer forces.

[0006] - injection reinforcement - introduction of special compounds into cavities and cracks of the arch to restore the integrity of the structure.

[0007] Disclosure of invention

[0008] The proposed method for strengthening an arch bridge combines several technologies, namely, strengthening the semi-arches relative to the central axis of the supports, transforming the arch system into an arch-cantilever system, which removes the load-bearing loads from the arch vault and transfers the load to an arch-cantilever T-shaped structure formed by two semi-arches adjacent to the support, the semi-arches themselves and the beams between them.

[0009] The objective of the proposed solution is to create a method for strengthening a reinforced concrete arch bridge, each arch of which consists of two semi-arches resting on supports, which will eliminate the need for a complete replacement of the bridge structure.

[0010] The technical result of the proposed solution is: restoration and strengthening of the bearing capacity of the arch bridge while maintaining the geometry.

[0011] The technical result is achieved through the use of a method for strengthening a reinforced concrete arch bridge. Each arch consists of two semi-arches and rests on piers, with the beams resting at one end on the piers and the other on the semi-arches. The pavement is first removed and the bridge elements are cleaned. The bridge's shore piers are reinforced by installing ground anchors in combination with a monolithic anchor block, and the bridge semi-arches are reinforced by connecting two semi-arches adjacent to the pier with the beams resting on them. First, the two beams adjacent to the pier and their pier are connected with prestressed high-strength strands, securing the strands with anchors to the semi-arches on which the beams rest. Next, a second upper tier of prestressed high-strength strands is installed, connecting the two semi-arches adjacent to the pier, the two beams, and their pier. The strands are secured with anchors on opposite sides of the semi-arches, thus forming an arched-cantilever T-shaped structure.Strands are pulled through the inter-beam space in both tiers, and then the inter-beam space containing the strands is grouted with fiber-reinforced concrete. Additionally, hinged supports are installed where the semi-arches rest on the bridge piers, and then the arched-cantilever T-shaped structure is also grouted with fiber-reinforced concrete. Expansion joints are installed at the arch apex areas, and finally, the road surface is laid.

[0012] The essence of the invention is explained by drawings, where:

[0013] Fig. 1. - Schematically depicts the unification of two semi-arches adjacent to the support.

[0014] Fig. 2 - Schematically shows a part of the reinforced bridge.

[0015] A method for strengthening a reinforced concrete arch bridge 1, each arch 2 of which consists of two semi-arches 3 and rests on supports 4, and beams 5 rest at one end on supports 4, and the other on semi-arches 3. First, the road surface is removed and the elements of the bridge 1 are cleaned. The coastal supports 6 of the bridge are strengthened by installing ground anchors 7 in combination with a monolithic anchor block 8 and the semi-arches 3 of the bridge 1 are strengthened, while connecting two semi-arches 3 adjacent to support 4 with beams 5 lying on them. First, two beams 5 adjacent to support 4 and their support 4 are connected with prestressed high-strength strands 9, fixing the strands 9 with anchors 12 on the semi-arches 3 on which beams 5 rest, obtaining the first lower tier 10 of prestressed high-strength strands 9. Next, a second upper tier 11 of prestressed high-strength strands 9 is organized, connecting with them two semi-arches 3 adjacent to support 4, two beams 5 and their support 4.Strands 9 are secured with anchors 12 on opposite sides of semi-arches 3, thereby forming an arched-cantilever T-shaped structure 13. Strands 9 in both tiers 10 and 11 are pulled through the inter-beam space, and then the inter-beam space with strands 9 is monolithed with fiber-reinforced concrete. Additionally, hinged bearing parts 14 are installed at the points where semi-arches 3 rest on piers 4 of bridge 1, and then the arched-cantilever T-shaped structure 13 is also monolithed with fiber-reinforced concrete. Expansion joints 15 are installed in the areas of the tops of arches 2, and finally the road surface is laid.

[0016] Arch-cantilever bridge structures consist of two semi-arches connected to each other and shaped like the letter T. In such structures, the semi-arches are connected in pairs by ties.

[0017] A monolithic anchor block is a reinforced concrete product designed to fix wind braces in bridge structures.

[0018] A ground anchor transfers tensile forces from building structures to the ground. By adhering to dense soil layers, the anchor prevents the structure from shifting, tipping, or deforming.

[0019] Hinged bridge arch supports reduce the moments arising from temperature deformations and support displacements compared to hingeless arches. Hinges at the elastic points prevent the transfer of bending moments to the bridge supports. Changes in the relative positions of the supports can alter the axial load exerted by the arch on the supports.

[0020] The proposed solution has undeniable advantages, namely:

[0021] - Arch-cantilever bridge designs combine the advantages of arch and cantilever sections, ensuring strength, cost-effectiveness, and stability. These advantages stem from the operating principles of the structural elements: arches and cantilevers. The arch structure transfers the load from the roadway not only to the supports but also to the lateral elements, which brace the arch and prevent its collapse. The cantilevers induce negative moments above the supports and reduce the positive moments in the spans.

[0022] - Arch-cantilever bridge structures are insensitive to uneven settlement of supports and do not affect internal forces, which allows them to be used on weak foundation soils.

[0023] - Hinged bridge arch supports (hinged arch bridges) reduce additional stresses from temperature deformations, support displacements, and uneven support settlements compared to non-hinged arches. This reduces bending moments in the arch, which reduces tensile stresses in the sections and prevents the transfer of bending moments to the bridge supports.

[0024] Industrial applicability

[0025] All of the above indicates the completion of the task and the achievement of the technical result, as well as the industrial applicability of the proposed method.

[0026] List of items:

[0027] 1. Reinforced concrete arch bridge

[0028] 2. Arch

[0029] 3. semi-arch

[0030] 4. support

[0031] 5. beam

[0032] 6. Coastal support

[0033] 7. Ground anchor

[0034] 8. Monolithic anchor block

[0035] 9. Prestressed high-strength strands

[0036] 10. First lower tier of prestressed high-strength strands

[0037] 11. Second upper tier of prestressed high-strength strands

[0038] 12. Anchors

[0039] 13. Arched-console T-shaped structure

[0040] 14. Hinged support part

[0041] 15. Expansion joint

Images