A method for maintaining the structural performance of a flange plate

Abstract

The present invention discloses a method for maintaining the structural performance of a flange plate, including the state evaluation of the concrete T-beam flange plate structure, the appearance shape and parameters of the outer reinforcement structure, and the connection form between the reinforcement structure and the beam structure. This solution and method can reinforce the existing concrete T-beam structure to improve the bearing capacity of the concrete T-beam flange plate structure and ensure the safety of the T-beam structure.

Description

Technical Field

[0001] The present invention relates to the field of full-scale model test reinforcement of concrete beams, and particularly to a method and system for maintaining the structural performance of flange plates. Background Art

[0002] Concrete T-beams are beam structural forms widely used in railways, highways, and urban roads at home and abroad. This structural form can give full play to the good material properties of concrete and the mechanical properties of the beam structural form, so as to achieve the long-term good load-bearing effect of the beam structure. The railway bridges in our country are mainly prestressed concrete beam bridges, with clear mechanical properties and simple structures, which can provide the stiffness and stability to meet the train operation requirements. Among them, prestressed concrete T-beams have the advantages of high bearing capacity, less material consumption, small self-weight, good stability, and convenient construction and erection, and are typical beam structural forms in bridge construction, with extensive applications in railway bridges.

[0003] The concrete T-beam structure of railway bridges is provided with a vertical ballast retaining wall at the beam end of the T-beam, which can fix the ballast within a certain range under the rail, enabling the train to run smoothly and for a long time. During railway operation, due to the interaction between the train, the bridge, and the track, periodic vibrations and noises are generated. Therefore, when a railway bridge passes through sections with a large number of residents such as villages and cities, a noise prevention device needs to be set up. A sound barrier device is arranged on the outer side of the flange plate of the beam body of the concrete T-beam, and loads such as the self-weight of the structure, pedestrians, and wind pressure are transmitted to the ballast retaining wall and the flange plate through brackets and embedded T-steels. The flange plate of the simply supported T-beam sound barrier bears live loads such as wind loads and train aerodynamic forces during railway operation, and the sound barrier in coastal areas needs to consider the action of typhoon loads. The flange plate of the simply supported T-beam sound barrier that bears this load is a thin plate structure, and its structural stress mode is quite different from the theoretical calculation form. The root of the ballast retaining wall is a right-angle stress concentration area, and the flange at this place is a thin plate structure, resulting in cracks appearing prematurely after the structure bears the load, the steel bars failing to exert their tensile properties, and the durability and ultimate bearing capacity of the structure being reduced. Therefore, it is necessary to strengthen the flange plate structure of the concrete T-beam to ensure the safe use of the concrete bridge structure.

[0004] With the increasingly wide range of construction of concrete beam structures and the increase in the service time, some bridges have deteriorated and suffered from diseases. Using steel plates or steel members to reinforce the existing bridge structure is a commonly used reinforcement method at present. The structural reinforcement calculation method is an important method to determine the structural capacity at present, which can reflect the bearing capacity of the flange plate structure of the bridge after reinforcement.

[0005] In railway operation, there have been cases where the connection between the flange plate structure and the ballast retaining wall has cracked and the ballast retaining wall has fallen as a whole under various load actions, resulting in accidents such as line interruptions. Bridges are mostly used to cross the intersections of railway lines and highway lines, and the falling of the ballast retaining wall has a high probability of causing personal and property accidents. However, there is currently no method for comprehensively evaluating the structural state of the flange plate of a concrete T-beam, and there is a lack of effective reinforcement schemes and calculation methods for the flange plate structure of a concrete T-beam. There is an urgent need to design a reinforcement scheme and analyze the calculation method for the flange plate structure of a concrete T-beam to ensure the safety of the flange plate structure of a concrete T-beam.

[0006] Now, a method for maintaining the structural performance of the flange plate is needed to solve the above problems. Summary of the Invention

[0007] The present invention is to solve the problem that in the prior art, there is currently no method for comprehensively evaluating the structural state of the flange plate of a concrete T-beam, and there is a lack of effective reinforcement schemes and calculation methods for the flange plate structure of a concrete T-beam. There is an urgent need to design a reinforcement scheme and analyze the calculation method for the flange plate structure of a concrete T-beam to ensure the safety of the flange plate structure of a concrete T-beam. A method for maintaining the structural performance of the flange plate is provided to solve the above problems.

[0008] The present invention provides a method for maintaining the structural performance of the flange plate, including the following steps:

[0009] S1. Evaluate the structural state of the flange plate to determine whether the current flange plate needs to be reinforced. If so, proceed to step S2; otherwise, output the structural state of the flange plate.

[0010] S2. Select a reinforcement device according to the actual situation of the flange plate.

[0011] S3. Select the connection form of the flange plate reinforcement device according to the actual needs and install it.

[0012] S4. Select the section with the maximum load-bearing capacity as the first check section, the section with the smallest cross-sectional dimension as the second check section, the section with stress concentration as the third check section, and the section with significant changes in the cross-section as the fourth check section.

[0013] S5. Calculate the structural bearing capacity.

[0014] S6. Evaluate the structural performance of the reinforced flange plate according to the structural bearing capacity.

[0015] The first checking section is selected because this section is located in the stress concentration area and cracks are likely to occur, so it is selected as the checking section; the second checking section is because the load acts most significantly at this position, and it is the connection part between the flange plate and the main girder, where the structural stiffness changes significantly; the third checking section is because this section is located in the stress concentration area where the flange plate meets the ballast retaining wall, so it is used as the checking section; the fourth checking section is because after reinforcement, this section is at the edge of the reinforcement structure and there is a significant change in structural stiffness, so it is used as the checking section.

[0016] In a method for maintaining the structural performance of a flange plate according to the present invention, as a preferred embodiment, the reinforcement device includes a reinforcement steel plate, a steel plate stiffener and an anchor bolt. The shape of the reinforcement steel plate is the same as the outer shape of the T-beam flange plate. The steel plate stiffener is arranged on the outer surface of the reinforcement steel plate, and the anchor bolt passes through the reserved bolt hole of the reinforcement steel plate and is anchored to the flange plate structure;

[0017] The thickness of the reinforcement steel plate is 10 - 40 mm, the height of the vertical part of the reinforcement steel plate is 100 - 600 mm, the length of the horizontal part is 100 - 2000 mm, the thickness of the stiffener is 10 - 40 mm, the height is 10 - 150 mm, the number of stiffeners is 1 - 10, the diameter of the anchor bolt is 6 - 56 mm, and the length is 10 - 300 mm.

[0018] In a method for maintaining the structural performance of a flange plate according to the present invention, as a preferred embodiment, the structural state evaluation in step S1 specifically includes: performing appearance inspection, crack detection and steel bar cover thickness test on the flange plate respectively;

[0019] The specific evaluation method for appearance inspection is as follows:

[0020]

[0021] Among them, R1 is the damage coefficient of appearance inspection, T1 is the inclination angle of the ballast retaining wall, T2 is the damaged area of the key inspection area, M1 is the limit value of the inclination of the ballast retaining wall, and M2 is the total area of the key inspection area;

[0022] The specific evaluation method for crack detection is as follows:

[0023]

[0024] Among them, R2 is the damage coefficient of crack detection, H1 is the longitudinal length of the crack in the key inspection area, H2 is the width of the crack in the key inspection area, K1 is the total longitudinal length of the flange plate inspection area, and K2 is the limit value of the crack width of the T-beam flange plate structure;

[0025] The specific evaluation method for steel bar cover thickness test is as follows:

[0026]

[0027] Among them, R3 is the damage coefficient for the test of the steel bar protection layer thickness, F1 is the test value of the upper-layer transverse steel bar protection layer thickness of the flange plate in the key inspection area, F2 is the designed value of the upper-layer transverse steel bar protection layer thickness of the flange plate in the key inspection area, and P is the over-thickness limit value of the upper-layer transverse steel bar protection layer thickness of the flange plate in the key inspection area;

[0028] Calculate the state result R of the concrete T-beam flange plate structure, and the formula is as follows:

[0029]

[0030] Among them, Pi is the dynamic weighting factor of the detection system, which shows the influence of the key indicators of the connection structure on the structure state through dynamic weighting; Ri is the damage coefficient of each detection system;

[0031] Based on the state result R of the concrete T-beam flange plate structure, draw a conclusion on whether the current flange plate needs to be strengthened.

[0032] As a preferred method, for the method for maintaining the structural performance of the flange plate described in the present invention, the installation method in step S3 is specifically to fix the reinforcement steel plate on the outside of the flange plate structure in the form of implanting anchor bolts, and the installation steps are as follows:

[0033] S31. Detect the steel bar situation at the specified position and determine the drilling position points;

[0034] S32. Use tools to drill holes to reach the specified depth, and the hole diameter meets the requirements for bolt insertion;

[0035] S33. Clean the holes by using a high-strength blower and wool, etc., and clean all the sundries and dust inside and near the drilled holes;

[0036] S34. Insert all the bolts, conduct a trial installation of the reinforcement steel plate, and adjust the hole positions in a timely manner;

[0037] S35. After the reinforcement steel plate is temporarily fixed, inject the evenly mixed glue into the drilled holes, filling 2 / 3 of the drilled hole volume;

[0038] S36. Within the operable time, slowly screw the bolts into the drilled holes, with a small amount of glue overflowing, clean the glue overflowing on the surface, and do not disturb the bolts during the curing period;

[0039] S37. After the glue is completely hardened, inject a sufficient amount of low-viscosity glue into the gap between the steel plate and the outside structure of the flange plate, and use high-viscosity glue to seal all the positions where the periphery of the reinforcement steel plate contacts the reinforcement structure.

[0040] A method for maintaining the structural performance of a flange plate. As a preferred method, the installation method in step S3 is specifically to fix the reinforcement steel plate on the outer side of the flange plate structure through through bolts. The installation steps are as follows:

[0041] S31. Detect the steel bar situation at the specified position and determine the drilling position points;

[0042] S32. Use tools to drill holes to form through holes, and the hole diameter meets the requirements for bolt insertion;

[0043] S33. Use a high-strength blower and brush to clean the holes, and clean all the sundries and dust inside and near the drilled holes;

[0044] S34. Insert all the bolts, conduct a trial installation of the reinforcement steel plate, and adjust the hole positions in a timely manner;

[0045] S35. After temporarily fixing the reinforcement steel plate, fix all the screw rods with bolts and apply a certain degree of pre-tightening force;

[0046] S36. Inject a sufficient amount of low-viscosity glue into the gap between the steel plate and the outer structure of the flange plate, and use high-viscosity glue to seal all the positions where the periphery of the reinforcement steel plate contacts the reinforcement structure.

[0047] A method for maintaining the structural performance of a flange plate. As a preferred method, the structural bearing capacity calculation method in step S5 is specifically as follows:

[0048] S51. According to the plane section assumption of strain, obtain the corresponding stress from the section deformation through the following formula:

[0049] σ c =ε c E c ;

[0050] σ s =ε s E s ;

[0051] Among them, σ c is the concrete stress; ε c is the concrete strain; E c is the concrete elastic modulus; σ s is the steel bar stress; ε s is the steel bar strain; E s is the steel bar elastic modulus;

[0052] S52. The section obtains the forces of the steel bars and concrete in the section according to the forces at each place. The formula is as follows:

[0053] F c =σ c A c ;

[0054] F s = σ s A s ;

[0055] Wherein, F c is the stress on the concrete; A c is the area of the concrete; F s is the stress on the steel bar; F s is the area of the steel bar;

[0056] S53. Calculate the stress and the lever arm H of the concrete and the steel bar according to the equilibrium equation. The equilibrium equation is:

[0057] F c + F s = 0;

[0058] S54. Assume that the section reaches the limit condition and calculate the section bearing capacity:

[0059] M = F s H;

[0060] Wherein, M is the section bearing capacity and H is the acting lever arm.

[0061] S54. According to the lever arms of each section, convert the calculated Mmax and Mmin of each inspection section into Fmax and Fmin acting on the top of the ballast retaining wall respectively. The formula is as follows:

[0062]

[0063]

[0064] Wherein, F is the converted load on the top of the ballast retaining wall; d is the lever arm from the inspection section to the ballast retaining wall;

[0065] S55. Through comprehensive comparison, obtain the minimum Fmaxi and Fmini, and obtain the corresponding Mmaxi and Mmini as the bearing capacity after the structure is strengthened.

[0066] The beneficial effects of the present invention are as follows:

[0067] (1) By using multiple key sections for inspection, considering the effect of the steel plate after strengthening, and through comprehensive comparison, obtain the bearing capacity of the strengthened structure to evaluate the bearing capacity of the strengthened structure;

[0068] (2) There are two connection methods for the steel plates used to reinforce the outer side of the flange plate of a concrete T-beam. The first connection method is characterized in that by drilling holes on the surface of the structure to be reinforced, after injecting glue into the holes, connecting rods are screwed into the holes to fix the reinforcing steel plates on the outer side of the structure to be reinforced, so as to achieve the goal of improving the structural bearing capacity; the second connection method is characterized in that by drilling through holes on the surface of the structure to be reinforced, connecting rods are inserted into the holes, and the reinforcing steel plates are fixed on the outer side of the structure to be reinforced through a connecting device, so as to achieve the goal of improving the structural bearing capacity.

[0069] (3) Conduct visual inspection, crack testing and reinforcement cover thickness testing on the structure of the flange plate of the concrete T-beam. Through comprehensive inspection of the concrete T-flange plate, evaluate the structural state of the flange plate of the concrete T-beam. Description of the Drawings

[0070] Figure 1 It is a schematic diagram of a method for maintaining the structural performance of a flange plate. Detailed Implementation Modes

[0071] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0072] Embodiment 1

[0073] As Figure 1 shown, a method for maintaining the structural performance of a flange plate includes the following steps:

[0074] S1. Evaluate the structural state of the flange plate to determine whether the current flange plate needs to be reinforced. If so, proceed to step S2; otherwise, output the structural state of the flange plate.

[0075] S2. Select a reinforcement device according to the actual situation of the flange plate.

[0076] S3. Select the connection form of the flange plate reinforcement device according to actual needs and install it.

[0077] S4. Select the section with the maximum load-bearing capacity as the first check section, the section with the smallest cross-sectional dimension as the second check section, the section with stress concentration as the third check section, and the section with significant changes in the cross-section as the fourth check section.

[0078] S5. Calculate the structural bearing capacity.

[0079] S6. Evaluate the structural performance of the reinforced flange plate according to the structural bearing capacity.

[0080] The reinforcement device includes a reinforcement steel plate, a steel plate stiffener, and an anchor bolt. The shape of the reinforcement steel plate is consistent with the outer shape of the T-beam flange plate. The steel plate stiffener is arranged on the outer surface of the reinforcement steel plate. The anchor bolt passes through the reserved bolt hole of the reinforcement steel plate and is anchored to the flange plate structure;

[0081] The thickness of the reinforcement steel plate is 10 - 40 mm. The height of the vertical part of the reinforcement steel plate is 100 - 600 mm, and the length of the horizontal part is 100 - 2000 mm. The thickness of the stiffener is 10 - 40 mm, the height is 10 - 150 mm, the number of stiffeners is 1 - 10, the diameter of the anchor bolt is 6 - 56 mm, and the length is 10 - 300 mm.

[0082] The stiffener is fixed to the reinforcement steel plate by welding to improve the stiffness and stability of the reinforcement steel plate. The reinforcement steel plate is provided with reserved bolt holes. After the anchor bolt is inserted, the reinforcement steel plate is fixed to the outer side of the flange plate structure by the way of post-inserted bar anchoring or through-fixing. The reinforcement steel plate is provided with exhaust holes. After the bolt is fixed, a low-viscosity glue can be injected through the gap between the steel plate and the outer structure of the flange plate to improve the adhesion and durability between the steel plate and the flange plate structure.

[0083] The structural state assessment in step S1 specifically includes: conducting visual inspection, crack detection, and steel bar cover thickness test on the flange plate respectively;

[0084] The specific evaluation method for visual inspection is as follows:

[0085]

[0086] Among them, R1 is the damage coefficient of visual inspection, T1 is the inclination angle of the ballast retaining wall, T2 is the damage area of the key inspection area, M1 is the limit value of the inclination of the ballast retaining wall, and M2 is the total area of the key inspection area;

[0087] The specific evaluation method for crack detection is as follows:

[0088]

[0089] Among them, R2 is the damage coefficient of crack detection, H1 is the longitudinal length of the crack in the key inspection area, H2 is the width of the crack in the key inspection area, K1 is the total longitudinal length of the inspection area of the flange plate, and K2 is the limit value of the crack width of the T-beam flange plate structure;

[0090] The specific evaluation method for steel bar cover thickness test is as follows:

[0091]

[0092] Among them, R3 is the damage coefficient for the test of the steel bar protection layer thickness, F1 is the measured value of the upper-layer transverse steel bar protection layer thickness of the flange plate in the key inspection area, F2 is the designed value of the upper-layer transverse steel bar protection layer thickness of the flange plate in the key inspection area, and P is the over-thickness limit value of the upper-layer transverse steel bar protection layer thickness of the flange plate in the key inspection area;

[0093] Calculate the state result R of the concrete T-beam flange plate structure, and the formula is as follows:

[0094]

[0095] Among them, Pi is the dynamic weighting factor of the detection system, which shows the influence of the key indicators of the connection structure on the structure state through dynamic weighting; Ri is the damage coefficient of each detection system;

[0096] Based on the state result R of the concrete T-beam flange plate structure, draw a conclusion on whether the current flange plate needs to be strengthened.

[0097] According to the influence of each sub-detection system on the damage degree of the T-beam flange plate structure, perform weighting, and the weights are as follows:

[0098] weighting coefficient weight crack state P2 40％ appearance state inspection coefficient P1 30％ steel bar cover thickness P3 30％

[0099] According to the interval range of the theoretical maximum value and the theoretical minimum value of the final result R and the damage degree, divide the final state result into 5 damage levels: slight, medium, relatively heavy, severe, and extremely severe;

[0100] The state of the concrete T-beam flange plate structure is divided into four levels: A, B, C, and D. Level A is further divided into two grades: AA and A1. Among them, level D is slight, level C is medium, level B is relatively heavy, A1 is severe, and AA is extremely severe. The evaluations and measures involved in each deterioration level are as follows in the table:

[0101]

[0102] Visual inspection is to observe the appearance state of the concrete T-beam flange plate structure with the naked eye, and check whether the retaining wall is significantly inclined and whether there are obvious damages on the appearance of the retaining wall; crack detection is to observe and detect the crack state and crack width of the concrete T-beam flange plate, and focus on checking the crack state at the intersection position of the retaining wall and the flange plate; the test of the steel bar protection layer thickness is to test the protection layer thickness of the steel bars of the concrete T-beam flange plate, and the protection layer thickness of the upper-layer transverse steel bars of the flange plate is the key point of the test.

[0103] In the inclination test, crack width test and steel bar protection layer thickness test, professional test instruments are required for measurement.

[0104] After visual inspection, crack detection and steel bar protection layer thickness, comprehensively evaluate the state of the concrete T-beam flange plate structure to determine whether the structure needs to carry out an anti-overturning test.

[0105] In step S3, the installation method is specifically to fix the reinforcement steel plate on the outer side of the flange plate structure by implanting anchor bolts. The installation steps are as follows:

[0106] S31. Detect the steel bar situation at the specified position to determine the drilling position points;

[0107] S32. Use tools to drill holes to reach the specified depth, and the hole diameter meets the requirements for bolt insertion;

[0108] S33. Use a high-strength blower to clean the holes, and clean all the sundries and dust inside and near the drilled holes;

[0109] S34. Insert all the bolts, conduct a trial installation of the reinforcement steel plate, and adjust the hole positions in a timely manner;

[0110] S35. After the reinforcement steel plate is temporarily fixed, inject the evenly mixed glue into the drilled holes to fill 2 / 3 of the drilled hole volume;

[0111] S36. Within the workable time, slowly screw the bolts into the drilled holes, with a small amount of glue overflowing. Clean the glue overflowing on the surface, and do not disturb the bolts during the curing period;

[0112] S37. After the glue is completely hardened, inject sufficient low-viscosity glue into the gap between the steel plate and the outer structure of the flange plate, and use high-viscosity glue to seal all the positions where the periphery of the reinforcement steel plate contacts the reinforcement structure.

[0113] In step S3, the installation method is specifically to fix the reinforcement steel plate on the outer side of the flange plate structure by through bolts. The installation steps are as follows:

[0114] S31. Detect the steel bar situation at the specified position to determine the drilling position points;

[0115] S32. Use tools to drill holes to form through holes, and the hole diameter meets the requirements for bolt insertion;

[0116] S33. Use a high-strength blower to clean the holes, and clean all the sundries and dust inside and near the drilled holes;

[0117] S34. Insert all the bolts, conduct a trial installation of the reinforcement steel plate, and adjust the hole positions in a timely manner;

[0118] S35. After the reinforcement steel plate is temporarily fixed, fix all the screw rods with bolts and apply a certain degree of pre-tightening force;

[0119] S36. Inject sufficient low-viscosity glue into the gap between the steel plate and the outer structure of the flange plate, and use high-viscosity glue to seal all the positions where the periphery of the reinforcement steel plate contacts the reinforcement structure.

[0120] The structural bearing capacity calculation method of step S5 is specifically as follows:

[0121] S51. According to the plane section assumption of strain, the corresponding stress is obtained from the section deformation through the following formula:

[0122] σ c =ε c E c ;

[0123] σ s =ε s E s ;

[0124] Among them, σ c is the concrete stress; ε c is the concrete strain; E c is the concrete elastic modulus; σ s is the steel bar stress; ε s is the steel bar strain; E s is the steel bar elastic modulus;

[0125] S52. The section obtains the forces of the steel bars and concrete in the section according to the forces at each place. The formula is as follows:

[0126] F c =σ c A c ;

[0127] F s =σ s A s ;

[0128] Among them, F c is the concrete force; A c is the concrete area; F s is the steel bar force; F s is the steel bar area;

[0129] S53. Calculate the forces and force arms H of the concrete and steel bars according to the equilibrium equation. The equilibrium equation is:

[0130] F c +F s =0;

[0131] S54. Assume that the section reaches the limit condition and calculate the section bearing capacity:

[0132] M=F s H;

[0133] Among them, M is the section bearing capacity and H is the acting force arm;

[0134] S55. According to the moment arms of each section, convert the calculated Mmax and Mmin of each inspection section into Fmax and Fmin acting on the top of the ballast retaining wall respectively. The formula is as follows:

[0135]

[0136] where F is the converted load at the top of the ballast retaining wall; d is the moment arm from the inspection section to the ballast retaining wall.

[0137] S56. Through comprehensive comparison, obtain the minimum Fmaxi and Fmini, and the corresponding Mmaxi and Mmini are the bearing capacities after the structure is strengthened.

[0138] As mentioned above, the above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for maintaining the structural performance of a flange plate, characterized in that: It includes the following steps: S1. Evaluate the structural state of the flange plate to determine whether the current flange plate needs to be strengthened. If so, proceed to step S2; otherwise, output the structural state of the flange plate; S2. Select a strengthening device according to the actual situation of the flange plate; S3. Select the connection form of the flange plate strengthening device according to actual requirements and install it; S4. Select the section with the maximum load-bearing capacity as the first verification section, the section with the minimum cross-sectional size as the second verification section, the section with stress concentration as the third verification section, and the section with significant cross-sectional changes as the fourth verification section; S5. Calculate the structural bearing capacity; S6. Evaluate the structural performance of the strengthened flange plate according to the structural bearing capacity; The structural state evaluation described in step S1 specifically includes: visually inspecting the flange plate, detecting cracks, and testing the thickness of the steel bar cover; The specific evaluation method for the visual inspection is as follows: Wherein, R1 is the damage coefficient of the visual inspection, T1 is the inclination angle of the ballast retaining wall, T2 is the damaged area of the key inspection area, M1 is the limit value of the inclination of the ballast retaining wall, and M2 is the total area of the key inspection area; The specific evaluation method for the crack detection is as follows: Wherein, R2 is the damage coefficient of the crack detection, H1 is the longitudinal length of the crack in the key inspection area, H2 is the width of the crack in the key inspection area, K1 is the total longitudinal length of the flange plate inspection area, and K2 is the limit value of the crack width of the T-beam flange plate structure; The specific evaluation method for the steel bar cover thickness test is as follows: Wherein, R3 is the damage coefficient of the steel bar cover thickness test, F1 is the test value of the upper-layer transverse steel bar cover thickness of the flange plate in the key inspection area, F2 is the design value of the upper-layer transverse steel bar cover thickness of the flange plate in the key inspection area, and P is the over-thickness limit value of the upper-layer transverse steel bar cover thickness of the flange plate in the key inspection area; Calculate the state result R of the concrete T-beam flange plate structure, and the formula is as follows: Wherein, Pi is the dynamic weighting factor of the detection system, which shows the influence of the key indicators of the connection structure on the structural state through dynamic weighting; Ri is the damage coefficient of each detection system; Draw a conclusion on whether the current flange plate needs to be strengthened according to the state result R of the concrete T-beam flange plate structure.

2. The method for maintaining the structural performance of a flange according to claim 1, wherein: The strengthening device includes a strengthening steel plate, a steel plate stiffener, and an anchor bolt. The shape of the strengthening steel plate is the same as the outer shape of the T-beam flange plate. The steel plate stiffener is arranged on the outer surface of the strengthening steel plate. The anchor bolt passes through the reserved bolt hole of the strengthening steel plate and is anchored to the flange plate structure; The thickness of the strengthening steel plate is 10 - 40 mm, the height of the vertical part of the strengthening steel plate is 100 - 600 mm, the length of the horizontal part is 100 - 2000 mm, the thickness of the stiffener is 10 - 40 mm, the height is 10 - 150 mm, the number of stiffeners is 1 - 10, the diameter of the anchor bolt is 6 - 56 mm, and the length is 10 - 300 mm.

3. A method for maintaining the structural performance of a flange plate according to claim 1, characterized in that: The installation method in step S3 is specifically to fix the strengthening steel plate on the outer side of the flange plate structure by implanting anchor bolts. The installation steps are as follows: S31. Detect the steel bar situation at the specified position to determine the drilling position points; S32. Drill holes using tools to reach the specified depth, with the hole diameter meeting the requirements for bolt insertion; S33. Clear the holes by using a high-strength blower to clean all the debris and dust inside and near the drilled holes; S34. Insert all the bolts, conduct a trial installation of the reinforcement steel plate, and adjust the hole positions in a timely manner; S35. After temporarily fixing the reinforcement steel plate, inject the evenly mixed glue into the drilled holes to fill 2 / 3 of the drilled hole volume; S36. Slowly screw the bolts into the drilled holes within the workable time, with a small amount of glue overflowing. Clean the glue overflowing on the surface, and do not disturb the bolts during the curing period; S37. After the glue is completely hardened, inject a sufficient amount of low-viscosity glue into the gap between the steel plate and the outer structure of the flange plate, and use high-viscosity glue to seal all the positions where the periphery of the reinforcement steel plate contacts the reinforcement structure.

4. A method for maintaining the structural performance of a flange plate according to claim 1, characterized in that: The installation method in step S3 is specifically to fix the reinforcement steel plate on the outside of the flange plate structure through through bolts. The installation steps are as follows: S31. Detect the steel bar conditions at the specified position to determine the drilling position points; S32. Drill holes using tools to form through holes, with the hole diameter meeting the requirements for bolt insertion; S33. Clear the holes by using a high-strength blower to clean all the debris and dust inside and near the drilled holes; S34. Insert all the bolts, conduct a trial installation of the reinforcement steel plate, and adjust the hole positions in a timely manner; S35. After temporarily fixing the reinforcement steel plate, fix all the screw rods with bolts and apply a certain degree of pre-tightening force; S36. Inject a sufficient amount of low-viscosity glue into the gap between the steel plate and the outer structure of the flange plate, and use high-viscosity glue to seal all the positions where the periphery of the reinforcement steel plate contacts the reinforcement structure.

5. A method for maintaining the structural performance of a flange plate according to claim 1, characterized in that: The structural bearing capacity calculation method in step S5 is specifically as follows: S51. According to the assumption of plane section strain, obtain the corresponding stress from the section deformation through the following formula: σ c = ε c E c ; σ s = ε s E s ; Among them, σ c is the concrete stress; ε c is the concrete strain; E c is the elastic modulus of concrete; σ s is the steel bar stress; ε s is the steel bar strain; E s is the elastic modulus of the steel bar; S52. The section obtains the forces of the steel bars and concrete in the section according to the forces at each part. The formula is as follows: F c = σ c A c ; F s = σ s A s ; Among them, F c is the force on the concrete; A c is the area of the concrete; F s is the force on the steel bar; F s is the area of the steel bar; S53. Calculate the forces and the force arm H of the concrete and steel bars according to the equilibrium equation. The equilibrium equation is: F c +F s = 0; S54. Assume that the section reaches the ultimate condition and calculate the section bearing capacity: M = F s H; Among them, M is the section bearing capacity, and H is the acting force arm; S55. Convert the calculated Mmax and Mmin of each checked section to Fmax and Fmin acting on the top of the ballast retaining wall according to the force arms of each section. The formula is as follows: Among them, F is the converted load at the top of the ballast retaining wall; d is the force arm from the checked section to the ballast retaining wall; S56. Comprehensively compare to obtain the minimum Fmaxi and Fmini, and obtain the corresponding Mmaxi and Mmini as the bearing capacity after structural reinforcement.

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