Reinforcing structure and construction method for thin-walled pier of continuous rigid frame bridge

Abstract

The application belongs to the technical field of existing bridge reinforcement, and particularly relates to a reinforcing structure and a construction method for a thin-wall pier of a continuous rigid-frame bridge, which comprises a thin-wall pier foundation and a thin-wall pier vertically arranged on the thin-wall pier foundation, and a bridge deck arranged above the thin-wall pier; a reinforcing beam is arranged at the lower part of the thin-wall pier and located on the thin-wall pier foundation, the reinforcing beam covers the thin-wall pier along the circumference of the thin-wall pier, and the reinforcing beam protrudes from the thin-wall pier foundation along the circumference of the thin-wall pier foundation; the reinforcing structure further comprises reinforcing piles arranged below the reinforcing beam, and the reinforcing piles are arranged at both ends of the reinforcing beam along the bridge deck width direction L1. The reinforcing structure of the thin-wall pier ensures the structural stability of the existing continuous rigid-frame bridge and the thin-wall pier during construction and the process of the interval tunnel passing below.

Description

Technical Field

[0001] The present invention belongs to the technical field of existing bridge reinforcement, and in particular relates to a reinforcement structure and a construction method for a thin-walled pier of a continuous rigid frame bridge. Background Art

[0002] With the increasing network construction of urban rail transit projects, urban rail transit tunnel projects inevitably involve extensive underpasses of existing structures. When urban rail transit tunnels pass under conventional bridge pile foundations, the current established practice is to install a reinforced cap beam beneath the bridge foundation. This new pile foundation then transfers the bridge load to the ground, thereby strengthening the pile foundation.

[0003] A continuous rigid frame bridge is a bridge with consolidated piers and beams. The span beams of each span are continuous and consolidated at the pier tops, resulting in low longitudinal bending stiffness. Prestressed concrete box beams and thin-walled piers are typically used, making them suitable for long-span bridges. When urban rail transit tunnels pass under thin-walled piers of continuous rigid frame bridges, reinforcing cap beams installed beneath the foundations can create thin, strip-like cross-sections, resulting in low pier stiffness and limited capacity to withstand external additional loads, potentially leading to structural instability. More importantly, continuous rigid frame piers, continuous beams, and foundations all exhibit multiple statically indeterminate forces. This structure has very low tolerances to additional stresses caused by changes in its own stiffness and temperature. Extensive rebar planting around the piles can also significantly damage the thin-walled piers. Furthermore, changes in the flexible stiffness of the thin-walled piers must be kept within the regulatory tolerance of 5%, placing stringent requirements on the layout and design of the reinforcements. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a reinforcement structure and construction method for thin-walled piers of continuous rigid frame bridges, so as to ensure the structural stability of existing continuous rigid frame bridges and thin-walled piers during the construction of the thin-walled pier reinforcement structure and the process of passing through the interval tunnel.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows: a reinforcement structure for a thin-walled pier of a continuous rigid frame bridge includes a thin-walled pier foundation and a thin-walled pier vertically arranged on the thin-walled pier foundation, with a bridge deck arranged above the thin-walled pier; a reinforcement beam located on the thin-walled pier foundation is arranged at the lower part of the thin-walled pier, the reinforcement beam covers the thin-walled pier along the circumference of the thin-walled pier, and the reinforcement beam protrudes from the thin-walled pier foundation along the circumference of the thin-walled pier foundation;

[0006] It also includes reinforcement piles arranged below the reinforcement beam, and the reinforcement piles are arranged at both ends of the reinforcement beam along the bridge deck width direction L1.

[0007] Furthermore, the reinforced beam includes inner stirrups, beam reinforcement, outer stirrups and a concrete structure;

[0008] The concrete structure covers the thin-walled pier along the circumference of the thin-walled pier and protrudes from the thin-walled pier foundation along the circumference of the thin-walled pier foundation, and the upper ends of the reinforcement piles are connected to the concrete structure;

[0009] The inner stirrups, beam reinforcement and outer stirrups are all located in the concrete structure;

[0010] The inner stirrups and the outer stirrups are both horizontally arranged annular structures; the inner stirrups are arranged on the thin-walled pier; the outer stirrups are connected to the beam reinforcement and have a distance between them and the thin-walled pier.

[0011] Furthermore, the thin-walled pier is provided with a clamping groove arranged along its own circumference, and the inner stirrup is clamped in the clamping groove.

[0012] Furthermore, the inner stirrups and the outer stirrups are provided in plurality, and the plurality of the inner stirrups and the plurality of the outer stirrups are evenly distributed along the vertical direction.

[0013] Furthermore, it also includes a vertically arranged reinforcement ring, the reinforcement ring includes perforated steel bars arranged horizontally along the span direction L2, the perforated steel bars are installed through the thin-walled pier;

[0014] The two ends of the perforated steel bars are located outside the thin-walled pier and within the concrete structure; two perforated steel bars are provided, and the two perforated steel bars are spaced apart and arranged in parallel; the two perforated steel bars are connected by vertical bars, and both ends of the perforated steel bars are connected to the vertical bars;

[0015] There are multiple reinforcement rings, which are evenly distributed along the bridge deck width direction L1 and connected by horizontally arranged connecting ribs.

[0016] The construction method of the thin-wall pier reinforcement structure of a continuous rigid frame bridge comprises the following steps:

[0017] S1: Determine the location of foundation pit support piles and reinforcement piles based on the foundation pit outer contour line; and construct foundation pit support piles and reinforcement piles according to the design requirements;

[0018] Reinforcement piles are provided on both sides of the thin-walled pier foundation along the bridge deck width direction L1, and foundation pit support piles are provided on the side of the reinforcement piles away from the thin-walled pier foundation; multiple foundation pit support piles are provided, and the multiple foundation pit support piles are evenly distributed along the bridge span direction L2;

[0019] The top of the reinforcement pile is flush with the upper surface of the thin-walled pier foundation, and the top of the foundation pit support pile is higher than the top of the reinforcement pile;

[0020] S2: After the foundation pit support piles and reinforcement piles reach the design strength, the cap beams are installed on the foundation pit support piles. The cap beams are arranged along the bridge span direction L2. Cap beams are installed on both sides of the thin-walled pier foundation along the bridge deck width direction L1.

[0021] After the crown beam reaches the designed strength, a Bailey beam is installed along the width direction L1 of the bridge deck, with one end of the Bailey beam placed on one of the crown beams and the other end placed on the other crown beam; a vertical support structure for supporting the bridge deck is installed on the Bailey beam;

[0022] S3: Excavate the foundation pit downward to the thin-walled pier foundation, exposing the upper surface of the thin-walled pier foundation and the tops of the reinforcement piles. Construct a reinforcement beam below the thin-walled pier, placing the reinforcement beam on the thin-walled pier foundation and the reinforcement piles. The reinforcement beam circumferentially wraps around the thin-walled pier and protrudes from the thin-walled pier foundation. Both ends of the reinforcement beam along the bridge deck width direction L1 are supported by reinforcement piles.

[0023] S4: After the reinforced beam reaches the designed strength, backfill the foundation pit and remove the vertical support structure.

[0024] Furthermore, in step S3, the reinforcement beam located below the thin-walled pier is constructed, including the following steps:

[0025] A formwork is set up in the foundation pit so that the bottom plate of the formwork is placed on the reinforcement piles and the thin-walled pier foundation, and the side plates of the formwork are surrounded along the circumference of the thin-walled pier to form a pouring space located below the thin-walled pier and arranged along the circumference of the thin-walled pier;

[0026] A reinforcement ring is constructed, consisting of perforated steel bars arranged horizontally along the span direction L2. The main reinforcement positions of the thin-walled piers are detected and avoided, ensuring that the perforated steel bars penetrate the thin-walled piers and that both ends of the perforated steel bars are located outside the thin-walled piers. Two perforated steel bars are arranged parallel to each other, spaced apart from each other, and connected by vertical bars. Both ends of the perforated steel bars are connected to vertical bars, which are located within the casting space.

[0027] The inner stirrups are tied and fixed to the thin-walled pier along the circumference of the thin-walled pier; the beam reinforcement is installed in the casting space, and the outer stirrups are connected and fixed to the beam reinforcement. The outer stirrups are arranged along the circumference of the thin-walled pier and have a distance between them; the inner and outer stirrups are both arranged horizontally in a ring structure;

[0028] Pour concrete into the pouring space.

[0029] Furthermore, in the step S3, before the inner stirrups are tied and fixed on the thin-walled pier along the circumference of the thin-walled pier, the step further includes: drilling a groove on the thin-walled pier and clamping the inner stirrups in the groove.

[0030] Furthermore, in the step S3, before the inner stirrups are tied and fixed to the thin-walled pier along the circumference of the thin-walled pier, the step further includes: cleaning the outer surface of the thin-walled pier.

[0031] Furthermore, a deformation distance is set between the vertical support structure and the bridge deck in step S2.

[0032] Compared with the prior art, the beneficial effects of the present invention are: the present invention provides a reinforcement structure and construction method for thin-walled piers of continuous rigid frame bridges, which ensure the structural stability of existing continuous rigid frame bridges and thin-walled piers during the construction of the thin-walled pier reinforcement structure and the process of passing through the interval tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the cross-section structure of the present invention;

[0034] Figure 2 It is a schematic diagram of the planar structure of the present invention;

[0035] Figure 3 is a schematic diagram of the present invention;

[0036] Figure 4 It is a schematic structural diagram of the thin-walled pier, thin-walled pier foundation, reinforcement beam and reinforcement pile of the present invention;

[0037] Figure 5 It is a structural schematic diagram of the reinforcement ring of the present invention;

[0038] Figure numbers: 1-thin-walled pier foundation; 2-thin-walled pier; 201-slot; 3-bridge deck; 4-reinforcement beam; 401-inner stirrups; 402-outer stirrups; 403-concrete structure; 404-perforated steel bars; 405-vertical bars; 406-connecting bars; 5-reinforcement piles; 6-foundation pit; 7-foundation pit support piles; 8-crown beam; 9-Bailey beam; 10-vertical steel pipe support; 11-support beam; 12-section tunnel; 13-anchor rod. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and examples.

[0040] The reinforcement structure of the thin-walled pier of a continuous rigid frame bridge includes a thin-walled pier foundation 1, and a thin-walled pier 2 vertically arranged on the thin-walled pier foundation 1, and a bridge deck 3 is arranged above the thin-walled pier 2; the lower part of the thin-walled pier 2 is provided with a reinforcement beam 4 located on the thin-walled pier foundation 1, and the reinforcement beam 4 covers the thin-walled pier 2 along the circumference of the thin-walled pier 2, and the reinforcement beam 4 protrudes from the thin-walled pier foundation 1 along the circumference of the thin-walled pier foundation 1; it also includes reinforcement piles 5 arranged below the reinforcement beam 4, and the reinforcement piles 5 are provided at both ends of the reinforcement beam 4 along the bridge deck width direction L1.

[0041] Reinforcement piles 5 are located between two section tunnels 12. Thin-walled pier foundations 1 and reinforcement piles 5 together provide vertical support for reinforcement beams 4. By arranging reinforcement beams 4 around the circumference of thin-walled piers 2, they embrace the thin-walled piers 2, reinforcing them and increasing their strength, thereby enhancing the structural stability of the continuous rigid frame bridge.

[0042] The reinforcement beam 4 may include a concrete structure and beam reinforcement arranged in the concrete structure. In order to improve the connection strength between the reinforcement beam 4 and the thin-walled pier 2, preferably, the reinforcement beam 4 includes inner stirrups 401, beam reinforcement, outer stirrups 402 and a concrete structure 403; the concrete structure 403 covers the thin-walled pier 2 along the circumference of the thin-walled pier 2 and protrudes from the thin-walled pier foundation 1 along the circumference of the thin-walled pier foundation 1, and the upper end of the reinforcement pile 5 is connected to the concrete structure 403; the inner stirrups 401, beam reinforcement and outer stirrups 402 are all located in the concrete structure 403; the inner stirrups 401 and outer stirrups 402 are both horizontally arranged annular structures; the inner stirrups 401 are arranged on the thin-walled pier 2; the outer stirrups 402 are connected to the beam reinforcement and have a spacing between them and the thin-walled pier 2. The beam reinforcement provides installation support for the outer stirrups 402, and the thin-walled pier 2 provides installation support for the inner stirrups 401. The concrete structure 403 uses slightly expansive concrete, so that the outer stirrups 402 and the inner stirrups 401 generate a tightening force on the thin-walled pier 2, thereby increasing the vertical friction between the reinforced beam 4 and the thin-walled pier 2 and improving the connection strength between the reinforced beam 4 and the thin-walled pier 2.

[0043] In order to limit the position of the inner stirrups 401, preferably, the thin-walled pier 2 is provided with a clamping groove 201 arranged along its own circumference, and the inner stirrups 401 are clamped in the clamping groove 201. The clamping groove 201 limits the position of the inner stirrups 401, so that the inner stirrups 401 are stably installed and tightly connected to the thin-walled pier 2.

[0044] As a preferred embodiment, a plurality of the inner stirrups 401 and the outer stirrups 402 are provided, and the plurality of the inner stirrups 401 and the plurality of the outer stirrups 402 are evenly distributed along the vertical direction.

[0045] In order to further improve the connection strength between the thin-walled pier 2 and the reinforced beam 4, it is preferred that a vertical reinforcement ring is further included. The reinforcement ring includes a perforated steel bar 404 arranged horizontally along the bridge span direction L2. The perforated steel bar 404 is installed through the thin-walled pier 2; the two ends of the perforated steel bar 404 are located outside the thin-walled pier 2 and within the concrete structure 403; there are two perforated steel bars 404, which are spaced up and down and arranged in parallel; the two perforated steel bars 404 are connected by a vertical bar 405, and the two ends of the perforated steel bars 404 are connected to the vertical bar 405; there are multiple reinforcement rings, which are evenly distributed along the bridge deck width direction L1 and connected by horizontally arranged connecting bars 406. By providing the reinforcement ring, the connection strength between the thin-walled pier 2 and the reinforced beam 4 is further improved, the shear bearing capacity is improved, and the integrity is better.

[0046] The construction method of the thin-wall pier reinforcement structure of a continuous rigid frame bridge comprises the following steps:

[0047] S1, according to the outer contour of the foundation pit 6, determine the position of the foundation pit support piles 7 and reinforcement piles 5 on site; construct the foundation pit support piles 7 and reinforcement piles 5 according to the design requirements;

[0048] Reinforcement piles 5 are provided on both sides of the thin-walled pier foundation 1 along the bridge deck width direction L1. Foundation pit support piles 7 are provided on the side of the reinforcement piles 5 away from the thin-walled pier foundation 1. Multiple foundation pit support piles 7 are provided, and the multiple foundation pit support piles 7 are evenly distributed along the bridge span direction L2.

[0049] The top of the reinforcement pile 5 is flush with the upper surface of the thin-walled pier foundation 1 , and the top of the foundation pit supporting pile 7 is higher than the top of the reinforcement pile 5 .

[0050] In order to improve the structural stability of the slope of the foundation pit 6 , preferably, the slope of the foundation pit 6 is anchored by anchor rods 13 .

[0051] S2: After the foundation pit support piles 7 and the reinforcement piles 5 have reached their designed strength, the crown beams 8 are installed on the foundation pit support piles 7. The crown beams 8 are arranged along the bridge span direction L2. The crown beams 8 are installed on both sides of the thin-walled pier foundation 1 along the bridge deck width direction L1.

[0052] After the crown beam 8 reaches the designed strength, a Bailey beam 9 is constructed along the width direction L1 of the bridge deck, with one end of the Bailey beam 9 placed on one of the crown beams 8 and the other end placed on the other crown beam 8; a vertical support structure for supporting the bridge deck 3 is installed on the Bailey beam 9.

[0053] Specifically, the vertical support structure includes vertical steel tubular supports 10, multiple of which are evenly distributed along the circumference of the thin-walled pier 2. A support beam 11, located adjacent to the bridge deck 3, is installed above the multiple vertical steel tubular supports 10. A deformation gap is provided between the support beam 11 and the lower surface of the bridge deck 3. The bridge deck 3, support beam 11, vertical steel tubular supports 10, Bailey beam 9, and crown beam 8 are arranged in this order from top to bottom. These support beams 11, vertical steel tubular supports 10, Bailey beam 9, and crown beam 8 provide auxiliary support for the bridge deck 3, improving construction safety.

[0054] S3: Excavate the foundation pit 6 downward to the thin-walled pier foundation 1, exposing the upper surface of the thin-walled pier foundation 1 and the tops of the reinforcement piles 5. Install the reinforcement beam 4 below the thin-walled pier 2, placing it on the thin-walled pier foundation 1 and the reinforcement piles 5. The reinforcement beam 4 circumferentially wraps around the thin-walled pier 2 and protrudes from the thin-walled pier foundation 1. Both ends of the reinforcement beam 4 along the bridge deck width direction L1 are supported by the reinforcement piles 5.

[0055] Crown beam 8 is located at the top of foundation pit 6. A supporting surface is provided at the top edge of foundation pit 6 to support the end of crown beam 8 and prevent it from sinking. After excavation of foundation pit 6, the upper surface of thin-walled pier foundation 1 and the tops of reinforcement piles 5 are exposed, facilitating the subsequent construction of reinforcement beam 4. The completed reinforcement beam 4 is located at the bottom of foundation pit 6, with a gap between crown beam 8 and reinforcement beam 4. The reinforcement piles 5 and thin-walled pier foundation 1 together provide vertical support for reinforcement beam 4.

[0056] Preferably, in step S3, the reinforcement beam 4 located below the thin-walled pier 2 is constructed, including the following steps:

[0057] A formwork is set up in the foundation pit 6 so that the bottom plate of the formwork is placed on the reinforcement piles 5 and the thin-walled pier foundation 1, and the side plates of the formwork are surrounded along the circumference of the thin-walled pier 2 to form a pouring space located below the thin-walled pier 2 and arranged along the circumference of the thin-walled pier 2;

[0058] A reinforcement ring is constructed, comprising perforated steel bars 404 arranged horizontally along the span direction L2. The main reinforcement positions of the thin-walled pier 2 are detected and avoided, so that the perforated steel bars 404 pass through the thin-walled pier 2 and both ends of the perforated steel bars 404 are located outside the thin-walled pier 2. Two perforated steel bars 404 are arranged parallel to each other, and the upper and lower perforated steel bars 404 are connected by vertical bars 405. Both ends of the perforated steel bars 404 are connected to the vertical bars 405, and the vertical bars 405 are located in the casting space.

[0059] The inner stirrups 401 are tied and fixed to the thin-walled pier 2 along the circumference of the thin-walled pier 2; the beam reinforcement is installed in the casting space, and the outer stirrups 402 are connected and fixed to the beam reinforcement. The outer stirrups 402 are arranged along the circumference of the thin-walled pier 2 and are spaced apart from the thin-walled pier 2; the inner stirrups 401 and the outer stirrups 402 are both horizontally arranged annular structures;

[0060] Pour concrete into the pouring space.

[0061] Preferably, in step S3 , before the inner stirrups 401 are tied and fixed to the thin-walled pier 2 along the circumference of the thin-walled pier 2 , the step further includes: drilling a groove 201 on the thin-walled pier 2 , and clamping the inner stirrups 401 in the groove 201 .

[0062] Preferably, in the step S3, before the inner stirrups 401 are tied and fixed on the thin-walled pier 2 along the circumference of the thin-walled pier 2, the step further includes: cleaning the outer surface of the thin-walled pier 2.

[0063] S4: After the reinforced beam 4 reaches the designed strength, the foundation pit 6 is backfilled and the vertical support structure is removed.

[0064] Dismantling the vertical support structure specifically refers to dismantling the vertical steel pipe support 10 and the support beam 11 .

[0065] This solution has been applied to the thin-walled pier reinforcement of the Rennan Interchange Bridge between Nijiaqiao Station and the South Railway Station in the third phase of Chengdu Metro Line 18. The displacement of the foundation and deck of the existing continuous rigid frame bridge was controlled to within 5mm, meeting the regulatory requirement of less than 10mm.

[0066] The above is a specific implementation method of the present invention. It can be seen from the implementation process that the present invention provides a reinforcement structure and construction method for thin-walled piers of continuous rigid frame bridges, which ensure the structural stability of existing continuous rigid frame bridges and thin-walled piers during the construction of the thin-walled pier reinforcement structure and the process of passing through the interval tunnel.

Claims

1. A reinforcement structure for a thin-walled pier of a continuous rigid frame bridge, comprising a thin-walled pier foundation (1), and a thin-walled pier (2) vertically arranged on the thin-walled pier foundation (1), wherein a bridge deck (3) is arranged above the thin-walled pier (2); characterized in that: A reinforcing beam (4) located on the thin-walled pier foundation (1) is provided at the lower portion of the thin-walled pier (2), the reinforcing beam (4) covering the thin-walled pier (2) along the circumference of the thin-walled pier (2), and the reinforcing beam (4) protruding from the thin-walled pier foundation (1) along the circumference of the thin-walled pier foundation (1); It also includes reinforcement piles (5) arranged below the reinforcement beam (4), and the reinforcement piles (5) are arranged at both ends of the reinforcement beam (4) along the bridge deck width direction L1; The reinforced beam (4) comprises inner stirrups (401), beam reinforcement, outer stirrups (402) and a concrete structure (403); The concrete structure (403) covers the thin-walled pier (2) along the circumference of the thin-walled pier (2) and protrudes from the thin-walled pier foundation (1) along the circumference of the thin-walled pier foundation (1), and the upper end of the reinforcement pile (5) is connected to the concrete structure (403); The inner stirrups (401), beam reinforcement and outer stirrups (402) are all located in the concrete structure (403); The inner stirrups (401) and the outer stirrups (402) are both horizontally arranged annular structures; the inner stirrups (401) are arranged on the thin-walled pier (2); the outer stirrups (402) are connected to the beam reinforcement and have a spacing between them and the thin-walled pier (2); It also includes a vertically arranged reinforcement ring, the reinforcement ring including perforated steel bars (404) arranged horizontally along the bridge span direction L2, the perforated steel bars (404) being installed through the thin-walled pier (2); The two ends of the perforated steel bars (404) are located outside the thin-walled pier (2) and inside the concrete structure (403); two perforated steel bars (404) are provided, and the two perforated steel bars (404) are spaced apart and arranged in parallel; the two perforated steel bars (404) are connected by vertical bars (405), and both ends of the perforated steel bars (404) are connected to the vertical bars (405); A plurality of reinforcing rings are provided, and the plurality of reinforcing rings are evenly distributed along the width direction L1 of the bridge deck and are connected by horizontally arranged connecting ribs (406).

2. The reinforcement structure of the thin-walled pier of a continuous rigid frame bridge according to claim 1, characterized in that: The thin-walled pier (2) is provided with a clamping groove (201) arranged along its own circumference, and the inner stirrup (401) is clamped in the clamping groove (201).

3. The reinforcement structure of the thin-walled pier of a continuous rigid frame bridge according to claim 1, characterized in that: A plurality of the inner stirrups (401) and the outer stirrups (402) are provided, and the plurality of the inner stirrups (401) and the plurality of the outer stirrups (402) are evenly distributed along the vertical direction.

4. A construction method for reinforcing a thin-walled pier of a continuous rigid frame bridge, characterized in that: The construction of the reinforcement structure of the thin-walled pier of the continuous rigid frame bridge according to any one of claims 1 to 3 comprises the following steps: S1, according to the outer contour line of the foundation pit (6), the positions of the foundation pit support piles (7) and the reinforcement piles (5) are determined by on-site layout; the foundation pit support piles (7) and the reinforcement piles (5) are constructed according to the design requirements; Reinforcement piles (5) are provided on both sides of the thin-walled pier foundation (1) along the bridge deck width direction L1, and foundation pit support piles (7) are provided on the side of the reinforcement piles (5) away from the thin-walled pier foundation (1); a plurality of foundation pit support piles (7) are provided, and the plurality of foundation pit support piles (7) are evenly distributed along the bridge span direction L2; The top of the reinforcement pile (5) is flush with the upper surface of the thin-walled pier foundation (1), and the top of the foundation pit support pile (7) is higher than the top of the reinforcement pile (5); S2, after the foundation pit support piles (7) and the reinforcement piles (5) reach the design strength, a crown beam (8) is constructed on the foundation pit support piles (7), and the crown beam (8) is arranged along the bridge span direction L2; the thin-walled pier foundation (1) is constructed with crown beams (8) on both sides along the bridge deck width direction L1; After the crown beam (8) reaches the designed strength, a Bailey beam (9) is constructed and arranged along the width direction L1 of the bridge deck, with one end of the Bailey beam (9) being placed on one of the crown beams (8) and the other end being placed on the other crown beam (8); a vertical support structure for supporting the bridge deck (3) is installed on the Bailey beam (9); S3, excavating the foundation pit (6), excavating downward to the thin-walled pier foundation (1), exposing the upper surface of the thin-walled pier foundation (1) and the top of the reinforcement pile (5); constructing a reinforcement beam (4) located at the lower part of the thin-walled pier (2), placing the reinforcement beam (4) on the thin-walled pier foundation (1) and the reinforcement pile (5); the reinforcement beam (4) covers the thin-walled pier (2) along the circumferential direction and protrudes from the thin-walled pier foundation (1) along the circumferential direction, and both ends of the reinforcement beam (4) along the bridge deck width direction L1 are supported by the reinforcement pile (5); S4, after the reinforced beam (4) reaches the designed strength, the foundation pit (6) is backfilled and the vertical support structure is removed.

5. The construction method of the continuous rigid frame bridge thin-wall pier reinforcement structure according to claim 4, characterized in that: In the step S3, the reinforcement beam (4) is constructed at the lower portion of the thin-walled pier (2), including the following steps: A formwork is set up in the foundation pit (6), so that the bottom plate of the formwork is placed on the reinforcement pile (5) and the thin-walled pier foundation (1), and the side plates of the formwork are surrounded along the circumference of the thin-walled pier (2) to form a pouring space located below the thin-walled pier (2) and arranged along the circumference of the thin-walled pier (2); A reinforcement ring is constructed, the reinforcement ring comprising a perforated steel bar (404) arranged horizontally along the span direction L2 of the bridge, the main reinforcement position of the thin-walled pier (2) is detected, the main reinforcement position is avoided, and the perforated steel bar (404) passes through the thin-walled pier (2), and both ends of the perforated steel bar (404) are located outside the thin-walled pier (2); two perforated steel bars (404) are arranged in parallel with each other, and the upper and lower perforated steel bars (404) are connected by vertical bars (405), and both ends of the perforated steel bar (404) are connected to the vertical bars (405), and the vertical bars (405) are located in the casting space; The inner stirrups (401) are tied and fixed to the thin-walled pier (2) along the circumference of the thin-walled pier (2); the beam reinforcement is installed in the casting space, and the outer stirrups (402) are connected and fixed to the beam reinforcement, and the outer stirrups (402) are arranged along the circumference of the thin-walled pier (2) and have a spacing between them and the thin-walled pier (2); the inner stirrups (401) and the outer stirrups (402) are both horizontally arranged annular structures; Pour concrete into the pouring space.

6. The construction method of the continuous rigid frame bridge thin-wall pier reinforcement structure according to claim 5, characterized in that: In the step S3, before the inner stirrup (401) is tied and fixed on the thin-walled pier (2) along the circumference of the thin-walled pier (2), the step further includes: cutting a groove (201) on the thin-walled pier (2) and clamping the inner stirrup (401) in the groove (201).

7. The construction method of the continuous rigid frame bridge thin-wall pier reinforcement structure according to claim 5, characterized in that: In the step S3, before the inner stirrups (401) are tied and fixed on the thin-walled pier (2) along the circumference of the thin-walled pier (2), the step further includes: cleaning the outer surface of the thin-walled pier (2).

8. The construction method of the continuous rigid frame bridge thin-wall pier reinforcement structure according to claim 5, characterized in that: A deformation distance is provided between the vertical support structure and the bridge deck (3) in step S2.

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