Design method and system for seamless line of high-pier super-long-span suspension bridge

Abstract

The application discloses a high-pier super-large-span suspension bridge seamless track design method and system, establishes a line-bridge-pier integrated finite element model containing a steel rail, a sleeper, a track bed, a beam body, a support and a bridge pier / bridge tower based on bridge and track design parameters; based on the line-bridge-pier integrated finite element model, temperature load and train load are applied, and mechanical behavior analysis under different load conditions is carried out; based on the mechanical behavior analysis result, strength checking and stability checking of the main bridge range seamless track are carried out under preset load combination conditions, and if the checking result does not meet the specification requirement, the track design scheme is adjusted. The traditional design only pays attention to the beam end and ignores the blind area of the main tower and the midspan, the insufficient problem of beam-rail interaction under the multi-field coupling of the main bridge range caused by the special structure and the complex environment of the high-pier super-large-span bridge is solved, the track structure service life is prolonged by optimizing and locking the rail temperature, and the maintenance and repair cost of the whole life cycle is reduced.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, specifically to a seamless track design method and system for a high-pier, ultra-long-span suspension bridge. Background Technology

[0002] With the construction of mountain railways and bridges spanning canyons and rivers, the number of high-pier, ultra-long-span suspension bridges is increasing. Traditional seamless track design methods for bridges, such as those mainly designed for ordinary simply supported beam or continuous beam bridges, focus on load combinations and stress calculations at beam joints. When rail expansion joints are installed at the beam ends, the design focus naturally shifts to the joints themselves and their adjacent sections, assuming that the rail stress within the main bridge area has been effectively released.

[0003] However, this traditional design approach does not fully consider the beam-rail interaction characteristics of high-pier, ultra-long-span suspension bridges under the coupled effects of multiple fields such as temperature field (including overall temperature difference and cable-beam temperature difference) and train load. Existing calculations and analyses show that even with rail expansion joints at the ends of long-span suspension bridges, significant additional forces will still be generated on the rails in the bridge towers and mid-span areas of the main bridge (for example, a 1°C temperature change in a kilometer-class suspension bridge can generate approximately 24 kN of longitudinal force change in the rails at the bridge towers). This is mainly caused by the unique "temperature deflection effect" of suspension bridges. Traditional methods do not adequately calculate the additional forces in key areas such as bridge towers and mid-spans, leading to stress imbalances in the rails at these locations, affecting rail service life, and making it difficult to meet the design requirements of high-pier, ultra-long-span special structural bridges.

[0004] In summary, existing seamless track design methods for bridges have the following key technical problems when applied to high-pier, ultra-long-span special structure bridges (such as suspension bridges):

[0005] 1. Insufficient consideration of the stress on key parts of the main span

[0006] 1) Current technological status: Traditional theories and methods for seamless track design on bridges mainly focus on load combinations and stress calculations at beam joints. When rail expansion joints are installed at the beam ends, the design focus naturally shifts to the joints themselves and their adjacent sections.

[0007] 2) Existing problems: This traditional approach ignores the significant additional forces generated by the overall structural deformation of the main bridge area (such as bridge towers and mid-span) after the installation of expansion joints. Existing methods do not consider the main bridge area as a key region for stress calculation, leading to uneven stress distribution in the rails at this location and affecting their service life.

[0008] 2. The problem of insufficient consideration of the impact of complex environmental factors in multi-field coupling.

[0009] 1) Current technical status: Existing design specifications and theories are mainly based on the working conditions of ordinary bridges, neglecting the "temperature flexural effect" and failing to consider the changes in bridge alignment caused by the temperature difference between the main cable and the main girder (cable-girder temperature difference), and the additional longitudinal force generated in the rails as a result. Calculations show that for every 1°C change in the cable-girder temperature difference, approximately 5 kN of longitudinal force change can be generated in the rails at the bridge towers.

[0010] 2) Single load combination: The existing load combination does not include the additional stress caused by temperature deflection caused by temperature difference in cable beams, etc., which leads to the calculation results not matching the actual stress state. Summary of the Invention

[0011] This invention provides a seamless track design method and system for high-pier, ultra-long-span suspension bridges, to solve the problem that traditional seamless track design theory on bridges cannot effectively address the challenges of insufficient consideration of beam-rail interaction under multi-field coupling effects caused by the special structure and complex environment of high-pier, ultra-long-span bridges, as well as the gaps and deficiencies in design, calculation and control.

[0012] According to a first aspect, one embodiment provides a seamless alignment design method for a high-pier, ultra-long-span suspension bridge, the method comprising:

[0013] Based on the design parameters of bridges and tracks, an integrated finite element model of line-bridge-piers was established, including rails, sleepers, track bed, beams, supports, and piers / towers.

[0014] Based on the integrated finite element model of line-bridge-pier, temperature load and train load are applied to analyze the mechanical behavior under different load conditions.

[0015] Based on the mechanical behavior analysis results, a preset load combination condition is established to perform strength and stability checks on the seamless track within the main bridge area. If the check results do not meet the specifications, the track design scheme will be adjusted.

[0016] Furthermore, based on bridge and track design parameters, an integrated finite element model of the line-bridge-pier system is established, including rails, sleepers, track bed, beams, supports, and piers / towers. Specifically, this includes:

[0017] The components of the main tower and main girder of the suspension bridge are simulated using spatial beam elements, the main cable and suspenders are simulated using space rod elements under tension only, and the main girder deck is simulated using shell elements. Spring constraints are set at the bottom of the piers to simulate the actual longitudinal stiffness of the piers. The rails are simulated using beam elements that consider shear deformation, with full constraints at the ends. The sleepers are simulated using ordinary beam elements. The fasteners and track bed are simulated using three-dimensional spring elements, with linear springs for vertical and lateral stiffness and nonlinear springs for longitudinal stiffness. The longitudinal resistance-displacement constitutive curves of the fasteners and track bed are taken with reference to the seamless track design specifications. To eliminate the influence of boundary effects, the seamless track on both sides of the main bridge extends outward by a predetermined length.

[0018] Furthermore, based on the integrated finite element model of line-bridge-pier, temperature loads and train loads are applied to analyze the mechanical behavior under different load conditions, specifically including:

[0019] Temperature load condition analysis, including:

[0020] Temperature loads are applied to each component in the finite element model. After loading calculation, the longitudinal force of the rail and the displacement results of the rail and beam are extracted. The temperature loads include the overall temperature rise and fall and the temperature difference between the cable and beam.

[0021] Overall temperature rise and fall: Calculate the mechanical effects of the bridge under overall temperature rise and fall loads. When optimizing the locked rail temperature, it is recommended that the beam temperature difference be half of the difference between the maximum monthly average temperature and the minimum monthly average temperature.

[0022] Cable-beam temperature difference: Calculate the temperature deflection effect caused when there is a temperature difference between the main cable / stayed cable and the main beam. It is recommended that the cable-beam temperature difference be taken as 10℃.

[0023] Furthermore, based on the integrated finite element model of line-bridge-pier, temperature loads and train loads are applied to analyze the mechanical behavior under different load conditions, specifically including:

[0024] Train load condition analysis includes:

[0025] Train loads at different locations were applied to the finite element model, and the longitudinal force of the rail and the displacement of the rail and beam surface were extracted after the loading calculation.

[0026] Furthermore, based on the results of mechanical behavior analysis, pre-set load combination conditions were established to perform strength and stability checks on the seamless track within the main bridge area, specifically including:

[0027] Seamless circuit strength calculation, including:

[0028] Calculate the combined rail stress and compare it with the allowable rail stress [σ] to determine whether the combined stress is less than or equal to the allowable stress [σ]. The formula is as follows:

[0029]

[0030]

[0031] In the formula:

[0032] σ d For the dynamic bending stress of the rail;

[0033] σ t This represents the maximum temperature stress of the rail.

[0034] σ ss Additional stress caused by the expansion and contraction of the bridge due to overall temperature rise and fall;

[0035] σ wn Additional stress caused by temperature deflection due to temperature difference in the cable beam;

[0036] σ ln Add stress to the train's flexural deformation;

[0037] σ s The yield strength of the rail steel;

[0038] [σ] represents the allowable stress of the rail;

[0039] K is the safety factor;

[0040] If the calculated combined stress is less than or equal to the allowable stress [σ], then the strength requirement is met.

[0041] Furthermore, based on the results of mechanical behavior analysis, pre-set load combination conditions were established to perform strength and stability checks on the seamless track within the main bridge area, specifically including:

[0042] Seamless circuit stability calculation includes:

[0043] Calculate the allowable temperature rise of seamless track on a suspension bridge:

[0044]

[0045] In the formula:

[0046] Temperature rise is permissible for seamless circuits;

[0047] E is the elastic modulus of the rail;

[0048] α is the coefficient of linear expansion of the rail;

[0049] F is the cross-sectional area of ​​the rail;

[0050] The allowable temperature and pressure for the two rails;

[0051] P ssAdditional stress caused by the expansion and contraction of the bridge due to overall temperature rise and fall;

[0052] P wn Additional stress caused by temperature deflection due to temperature difference in the cable beam;

[0053] P ln Add stress to the train's flexural deformation;

[0054] Calculate the allowable temperature rise Compared with the actual temperature rise in the local area, if the temperature rise is allowed... If the temperature rise is greater than the actual temperature increase, the stability requirement is met; otherwise, there is a risk of instability.

[0055] Furthermore, if the calculation results do not meet the specifications, the route design scheme will be adjusted, specifically including:

[0056] If the calculation results do not meet the specifications, adjustments will be made, including adjusting the locking rail temperature, installing low-resistance fasteners, or setting rail expansion joints. The modeling and analysis will then be repeated until both strength and stability meet the specifications.

[0057] Furthermore, the method also includes:

[0058] Based on different sections of the main bridge, including the main tower area, mid-span area, main beam transition area, and beam end area, the rail stress distribution, average stress level, and stress envelope characteristics under the most unfavorable load combination (i.e., combined stress) are analyzed. The rail locking temperature of the rails in different sections of the main bridge is then differentially optimized and adjusted to make the tensile stress and compressive stress of the rails tend to be balanced under normal operating conditions, thereby extending the service life of the rails.

[0059] According to a second aspect, one embodiment provides a seamless alignment design system for a high-pier, ultra-long-span suspension bridge, the system comprising:

[0060] The finite element modeling module is used to create an integrated finite element model of the line-bridge-pier, including rails, sleepers, track bed, beams, supports, and piers / towers, based on bridge and track design parameters.

[0061] The load condition analysis module is used to apply temperature loads and train loads to analyze the mechanical behavior under different load conditions based on the integrated finite element model of line-bridge-pier.

[0062] The seamless track calculation module is used to perform strength and stability calculations on the seamless track within the main bridge area based on the results of mechanical behavior analysis and to establish preset load combination conditions. If the calculation results do not meet the specifications, the track design scheme will be adjusted.

[0063] Furthermore, the system also includes:

[0064] The rail temperature optimization module is used to optimize the rail temperature in different sections of the main bridge, including the main tower area, mid-span area, main beam transition area, and beam end area, based on the stress distribution, average stress level, and stress envelope characteristics of the rail under the most unfavorable load combination, i.e., combined stress. This allows the tensile and compressive stresses of the rail to tend to be balanced under normal operating conditions, thereby extending the service life of the rail.

[0065] This invention provides a seamless track design method and system for high-pier, ultra-long-span suspension bridges, which has the following beneficial effects:

[0066] (1) Overcoming design blind spots and realizing a paradigm shift from "beam end" to "main span as well": This invention overcomes the blind spot of traditional design that only focuses on beam joints and ignores the stress on the rails in the main bridge area (especially the bridge towers and mid-span). By establishing an integrated model and focusing on analyzing the main span area, it is the first to incorporate the unique "temperature deflection effect" (caused by the temperature difference between the cable and beam) and the train deflection effect of suspension bridges into a seamless track calculation system in the main bridge area, filling the design gap in this field.

[0067] (2) A systematic load combination method for the main bridge area has been formed: This invention proposes for the first time a special load combination for the main bridge area of ​​a high-pier, ultra-long-span suspension bridge (including rail temperature stress, dynamic bending stress, expansion and contraction stress, temperature deflection stress, and train deflection stress), which solves the problem of no basis for the calculation of rails in the main bridge area under multi-field coupling action, and makes the calculation results closer to the actual engineering.

[0068] (3) A refined locking rail temperature control strategy was proposed: Based on the differential distribution of rail stress in different sections of the main bridge (such as mid-span and bridge tower), this invention proposes an innovative method for differential adjustment of locking rail temperature in different sections, which realizes precise and balanced control of rail stress, significantly extends the service life of the track structure, and reduces the maintenance cost throughout the entire life cycle. Attached Figure Description

[0069] Figure 1 A flowchart illustrating a seamless track design method for a high-pier, ultra-long-span suspension bridge, as provided in one embodiment of the present invention;

[0070] Figure 2 This is a flowchart illustrating the specific implementation of a seamless track design method for a high-pier, ultra-long-span suspension bridge according to an embodiment of the present invention.

[0071] Figure 3 This invention provides a schematic diagram of a suspension bridge subsystem in a full-bridge coupling model of a suspension bridge and seamless track in a design method for a high-pier, ultra-long-span suspension bridge, according to an embodiment of the present invention.

[0072] Figure 4This is a schematic diagram of the train load loading position in a seamless track design method for a high-pier, ultra-long-span suspension bridge according to an embodiment of the present invention.

[0073] Figure 5 This is a diagram showing the longitudinal force distribution of rails under overall temperature rise and fall of the bridge in a seamless track design method for a high-pier, ultra-long-span suspension bridge, as provided in an embodiment of the present invention.

[0074] Figure 6 This is a diagram showing the longitudinal force distribution of the rail under temperature difference in the cable beams in a seamless track design method for a high-pier, ultra-long-span suspension bridge, provided as an embodiment of the present invention.

[0075] Figure 7 This invention provides a diagram showing the longitudinal force distribution of rails within the main bridge under train deflection in a seamless track design method for a high-pier, ultra-long-span suspension bridge, as an embodiment of the present invention.

[0076] Figure 8 This is a stress envelope diagram of the rails within the main bridge area under combined loads in a seamless track design method for a high-pier, ultra-long-span suspension bridge, provided as an embodiment of the present invention. Detailed Implementation

[0077] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0078] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0079] The first embodiment of this invention provides a seamless track design method for a high-pier, ultra-long-span suspension bridge. This method overcomes the blind spots of traditional designs that only focus on the beam ends while neglecting the main tower and mid-span. It solves the problem of insufficient consideration of beam-rail interaction under multi-field coupling effects distributed throughout the main bridge area, caused by the special structure and complex environment of high-pier, ultra-long-span bridges. By optimizing the locking rail temperature, it extends the service life of the track structure and reduces the maintenance cost throughout its entire life cycle. The following is a combination of... Figure 1 and Figure 2 Please provide a detailed explanation.

[0080] like Figure 1 As shown, in step S100, based on the bridge and track design parameters, an integrated finite element model of the line-bridge-pier is established, including rails, sleepers, track bed, beams, supports, and piers / towers.

[0081] In this embodiment, an integrated finite element model of line-bridge-pier is established based on the design parameters of the bridge and track.

[0082] Specifically, using general-purpose finite element analysis software, a seamless track calculation coupled model is established, including rails, sleepers, track bed, beams, supports, and piers / towers. Figure 3 As shown. For suspension bridges, the geometric nonlinearity of the main cable and suspenders needs to be accurately simulated. Specifically, the chords, web members, and vertical members in the main tower and main girder of the suspension bridge are simulated using spatial beam elements; the main cable and suspenders are simulated using only tension spatial rod elements; and the main girder deck is simulated using shell elements. Spring constraints are set at the bottom of the piers to simulate the actual longitudinal stiffness of the piers. The rails are simulated using beam elements that can consider shear deformation, with full end constraints. The sleepers are simulated using ordinary beam elements. Fasteners and track bed are simulated using three-dimensional spring elements; vertical and lateral stiffness are achieved using linear springs, while longitudinal stiffness is achieved using nonlinear springs. The longitudinal resistance-displacement constitutive curves of the fasteners and track bed are taken from the "Seamless Track Design Code" (TB 10015). To eliminate the influence of boundary effects, the seamless track on both sides of the main bridge extends outward by 120m.

[0083] like Figure 1 As shown, in step S200, based on the integrated finite element model of line-bridge-pier, temperature load and train load are applied to analyze the mechanical behavior under different load conditions.

[0084] In this embodiment, temperature loads (including overall temperature difference and cable-beam temperature difference) are applied to the integrated finite element model based on the climatic conditions at the work site location. Figure 4 The provided train load and bridge location diagram indicate how to load the train load onto the bridge. Figure 4 In the text, 'a' and 'b' represent different loading positions of the train. Figure 4 The 'a' in the middle indicates entering the bridge from the left. Figure 4In the diagram, 'b' indicates entry into the bridge from the right. The influence of overall temperature difference, cable-beam temperature difference, and train load on the longitudinal force and displacement of the rails, and the relative displacement between the beam and rail, is analyzed.

[0085] Specifically, for the established integrated model, the following working conditions are calculated, and key results such as longitudinal force of the rail, longitudinal displacement of the rail, longitudinal displacement of the beam surface, and relative displacement between the beam and the rail are extracted.

[0086] (1) Temperature load analysis: Through finite element modeling (integrated finite element model of line-bridge-pier), temperature loads are applied to each component in the model. After loading calculation, the longitudinal force of the rail and the displacement results of the rail and beam surface are extracted.

[0087] 1) Overall temperature rise and fall: Calculate the mechanical effects of the bridge under overall temperature rise and fall loads. When optimizing the track temperature, it is recommended that the beam temperature difference be half of the difference between the maximum monthly average temperature and the minimum monthly average temperature.

[0088] 2) Cable-beam temperature difference: Calculate the temperature deflection effect caused when there is a temperature difference (positive and negative) between the main cable / stayed cable and the main beam. It is recommended that the cable-beam temperature difference be taken as 10℃.

[0089] (2) Train load condition analysis: Through finite element modeling (integrated finite element model of line-bridge-pier), train loads at different positions are applied in the model. After loading calculation, the longitudinal force of the rail and the displacement of the rail and beam surface are extracted.

[0090] By simulating trains at different locations (e.g.) Figure 4 As shown, the bridge undergoes deflection deformation when it passes through, and the additional longitudinal force generated in the rails as a result is calculated.

[0091] like Figure 1 As shown, in step S300, based on the mechanical behavior analysis results, a preset load combination condition is established to perform strength and stability checks on the seamless line within the main bridge area. If the check results do not meet the specification requirements, the line design scheme is adjusted.

[0092] The above steps specifically include:

[0093] S310 involves checking the strength, stability, and joint breaks of seamless rails within the main span of ultra-long span bridges to determine whether they meet the specifications.

[0094] (1) Defining a new load combination: Based on the analysis results of step S200, a load combination method for checking the strength and stability of seamless track in the main bridge range of high-pier ultra-long span bridges is proposed. The load combination should consider rail temperature stress, rail dynamic bending stress, additional stress due to train deflection, additional stress due to temperature load deflection, and additional stress due to bridge expansion and contraction.

[0095] The strength calculation combination for seamless track includes: 1) rail temperature stress (based on locked rail temperature); 2) rail dynamic bending stress; 3) bridge expansion and contraction stress (caused by overall temperature difference); 4) temperature deflection stress (mainly caused by cable-beam temperature difference); 5) train deflection stress; 6) rail traction (braking) stress.

[0096] The stability check combination includes: 1) rail temperature stress (based on locked rail temperature); 2) bridge expansion and contraction stress (caused by overall temperature difference); 3) temperature deflection stress (mainly caused by cable-beam temperature difference); 4) train deflection stress.

[0097] (2) Load combination description

[0098] 1) Load combination for strength calculation of seamless track rails on suspension bridges:

[0099]

[0100] In the formula:

[0101] σ d The dynamic bending stress of the rail (MPa);

[0102] σ t The maximum temperature stress of the rail (MPa);

[0103] σ ss The additional stress (MPa) caused by the overall temperature rise and fall of the bridge due to expansion and contraction.

[0104] σ wn The additional stress (MPa) caused by temperature deflection due to temperature difference in the cable beam;

[0105] σ ln Additional stress (MPa) is applied to the train's flexural stress.

[0106] σ Z For train traction (braking) stress;

[0107] σ s The yield strength (MPa) of rail steel is 457MPa for U71Mn and 472MPa for U75V.

[0108] [σ] represents the allowable stress of the rail (MPa);

[0109] K is the safety factor, which is set to 1.3.

[0110] 4) Seamless wiring on suspension bridges allows for temperature rise Calculate using the following formula:

[0111]

[0112] In the formula:

[0113] Temperature rise is permissible for seamless circuits;

[0114] E is the elastic modulus of the rail;

[0115] α is the coefficient of linear expansion of the rail, taken as 1.18 x 10. -5 / ℃;

[0116] F is the cross-sectional area of ​​the rail;

[0117] The allowable temperature and pressure for the two rails;

[0118] P ss Additional stress caused by the expansion and contraction of the bridge due to overall temperature rise and fall;

[0119] P wn Additional stress caused by temperature deflection due to temperature difference in the cable beam;

[0120] P ln This adds stress to the train's deflection.

[0121] (2) Perform a check:

[0122] 1) Strength check: The combined stress of the rail after considering the dynamic bending stress, temperature stress, additional stress from bridge expansion and contraction (overall temperature rise and fall), additional stress from temperature deflection (temperature difference between cable and beam), additional stress from train deflection, and rail traction (braking) stress is compared with the allowable stress of the rail (351MPa for U71Mn and 363MPa for U75V) to determine whether the combined stress is less than the allowable stress.

[0123] 2) Stability Calculation: For ballasted tracks, a stability analysis of the expanded rail track is conducted considering the rail temperature stress, bridge expansion and contraction stress, temperature deflection stress, and train deflection stress. First, the allowable temperature pressure [P] of the two rails is calculated according to the formula in the "Seamless Track Design Specification" (TB 10015). Then, the allowable temperature rise is calculated using the above formula. Compared with the actual temperature rise in the local area, the allowable temperature rise is determined. If the temperature rise is greater than the actual temperature increase, the stability requirement is met; otherwise, there is a risk of instability.

[0124] (3) Determine whether the result satisfies the requirements.

[0125] If the calculated results of rail strength, track stability, etc., do not meet the specification limits, it is necessary to take measures such as adjusting the locking rail temperature, arranging low-resistance fasteners (generally within 60m before and after the over-limit area), or installing rail expansion joints (generally at the over-limit point), and repeat the analysis in steps (i) to (iii) until the specification limits are met. Among them, low-resistance fasteners (replacing components such as spring clips and pads on the basis of constant-resistance fasteners) are generally arranged within 60m before and after the over-limit area. If arranging low-resistance fasteners still does not meet the specification requirements, then rail expansion joints (essentially disconnecting the rail, but allowing trains to run) should be installed.

[0126] Furthermore, the above method also includes: optimizing the design and control based on the analysis results, as detailed below:

[0127] (1) Optimize the locking rail temperature: Based on the stress state of the main bridge area (especially the main tower and mid-span) under the most unfavorable load combination (i.e., the combination of rail bending, rail temperature, bridge expansion and contraction (overall temperature rise and fall), temperature deflection (cable-beam temperature difference) and train deflection stress), the locking rail temperature of different sections of the main bridge area is optimized and adjusted (the tensile and compressive stresses of the rail under the stress combination of rail bending, rail temperature, bridge expansion and contraction (overall temperature rise and fall), temperature deflection (cable-beam temperature difference) and train deflection are calculated respectively, and the locking rail temperature is adjusted (affecting the temperature stress of the rail under tensile and compressive states, so that the combined rail tensile and compressive stresses are balanced), so that the rail tensile and compressive stresses are balanced under common conditions, and the service life of the rail is extended.

[0128] (2) Evaluation of track structure control measures: It can more realistically simulate the stress state of the rails on the suspension bridge. Based on the analysis of rail strength and stability, it can be determined whether small resistance fasteners and rail expansion joints need to be installed. If they need to be installed, their specific locations and models can be determined.

[0129] The following is an example of adjusting the locking rail temperature of a suspension bridge:

[0130] Taking a certain kilometer-level suspension bridge as the research object, a calculation model of the seamless track on the bridge was established, and the locking rail temperature analysis of the seamless track system on the suspension bridge was carried out.

[0131] (1) Overall temperature rise and fall of the bridge, Figure 5 A diagram showing the longitudinal force distribution of the rails under overall temperature rise and fall of the bridge;

[0132] (2) Temperature difference between cable beams Figure 6 This is a diagram showing the longitudinal force distribution of the rails under temperature differences in the cable-stayed beam.

[0133] (3) Train deflection, Figure 7 The longitudinal force of the rails within the main bridge area under the train's deflection;

[0134] (4) Track temperature adjustment: Combine dynamic bending stress, additional stress due to train load deflection, additional stress due to temperature load (cable-beam temperature difference) deflection, and additional stress due to bridge expansion and contraction (overall temperature rise and fall). The maximum stress envelope and average stress of tension and compression are as follows: Figure 8 As shown;

[0135] from Figure 8 As can be seen, the average stress of the rails within the main span of the suspension bridge is about 50 MPa, the average stress near the bridge tower is basically zero, and the average stress near the beam end is about 30 MPa (which is the average value of the dynamic bending stress of the rails). Therefore, in order to balance the tensile and compressive stress of the rails, it is recommended that the locking rail temperature in the mid-span range be set 10°C higher than the intermediate rail temperature, and the locking rail temperature in other areas of the main bridge be set 6°C higher than the intermediate rail temperature.

[0136] Corresponding to the above-disclosed method for seamless track design of a high-pier, ultra-long-span suspension bridge, this invention also discloses a seamless track design system for a high-pier, ultra-long-span suspension bridge, which specifically includes:

[0137] The finite element modeling module is used to create an integrated finite element model of the line-bridge-pier, including rails, sleepers, track bed, beams, supports, and piers / towers, based on bridge and track design parameters.

[0138] The load condition analysis module is used to apply temperature loads and train loads to analyze the mechanical behavior under different load conditions based on the integrated finite element model of line-bridge-pier.

[0139] The seamless track calculation module is used to perform strength and stability calculations on the seamless track within the main bridge area based on the results of mechanical behavior analysis and to establish preset load combination conditions. If the calculation results do not meet the specifications, the track design scheme will be adjusted.

[0140] Furthermore, the system also includes:

[0141] The rail temperature optimization module is used to optimize the rail temperature in different sections of the main bridge, including the main tower area, mid-span area, main beam transition area, and beam end area, based on the stress distribution, average stress level, and stress envelope characteristics of the rail under the most unfavorable load combination, i.e., combined stress. This allows the tensile and compressive stresses of the rail to tend to be balanced under normal operating conditions, thus extending the service life of the rail.

[0142] It should be noted that for a detailed description of the seamless track design system for a high-pier, ultra-long-span suspension bridge provided in the embodiments of the present invention, please refer to the relevant description of the seamless track design method for a high-pier, ultra-long-span suspension bridge provided in the embodiments of the present invention, which will not be repeated here.

[0143] In addition, embodiments of the present invention also provide an electronic device, the device comprising: a processor and a memory; the memory being used to store one or more program instructions; the processor being used to execute one or more program instructions to perform the steps of a seamless track design method for a high-pier, ultra-long-span suspension bridge as described in any of the preceding embodiments.

[0144] It should be noted that for a detailed description of the electronic device provided in the embodiments of the present invention, please refer to the relevant description of the seamless track design method for a high-pier, ultra-long-span suspension bridge provided in the embodiments of this application, which will not be repeated here.

[0145] In addition, embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the seamless track design method for a high-pier, ultra-long-span suspension bridge as described in any of the preceding claims.

[0146] It should be noted that for a detailed description of a computer-readable storage medium provided in the embodiments of the present invention, please refer to the relevant description of a seamless track design method for a high-pier, ultra-long-span suspension bridge provided in the embodiments of this application, which will not be repeated here.

[0147] Those skilled in the art will understand that all or part of the functions of the various methods in the above embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, which may include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to achieve the above functions. For example, the program can be stored in the memory of a device, and when the program in the memory is executed by the processor, all or part of the above functions can be achieved. In addition, when all or part of the functions in the above embodiments are implemented by computer programs, the program can also be stored in a server, another computer, disk, optical disk, flash drive, or external hard drive, etc., and can be downloaded or copied to the memory of a local device, or the system of the local device can be updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be achieved.

[0148] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A seamless track design method for a high-pier, ultra-long-span suspension bridge, characterized in that, The method includes: Based on the design parameters of bridges and tracks, an integrated finite element model of line-bridge-piers was established, including rails, sleepers, track bed, beams, supports, and piers / towers. Based on the integrated finite element model of line-bridge-pier, temperature load and train load are applied to analyze the mechanical behavior under different load conditions. Based on the mechanical behavior analysis results, a preset load combination condition is established to perform strength and stability checks on the seamless track within the main bridge area. If the check results do not meet the specifications, the track design scheme will be adjusted.

2. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, Based on bridge and track design parameters, an integrated finite element model of the line-bridge-pier system was established, including rails, sleepers, track bed, beams, supports, and piers / towers. Specifically, this included: The components of the main tower and main girder of the suspension bridge are simulated using spatial beam elements, the main cable and suspenders are simulated using space rod elements under tension only, and the main girder deck is simulated using shell elements. Spring constraints are set at the bottom of the piers to simulate the actual longitudinal stiffness of the piers. The rails are simulated using beam elements that consider shear deformation, with full constraints at the ends. The sleepers are simulated using ordinary beam elements. The fasteners and track bed are simulated using three-dimensional spring elements, with linear springs for vertical and lateral stiffness and nonlinear springs for longitudinal stiffness. The longitudinal resistance-displacement constitutive curves of the fasteners and track bed are taken with reference to the seamless track design specifications. To eliminate the influence of boundary effects, the seamless track on both sides of the main bridge extends outward by a predetermined length.

3. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, Based on the integrated finite element model of line-bridge-pier, temperature load and train load are applied to analyze the mechanical behavior under different load conditions, specifically including: Temperature load condition analysis, including: Temperature loads are applied to each component in the finite element model. After loading calculation, the longitudinal force of the rail and the displacement results of the rail and beam are extracted. The temperature loads include the overall temperature rise and fall and the temperature difference between the cable and beam. Overall temperature rise and fall: Calculate the mechanical effects of the bridge under overall temperature rise and fall loads. When optimizing the locked rail temperature, it is recommended that the beam temperature difference be half of the difference between the maximum monthly average temperature and the minimum monthly average temperature. Cable-beam temperature difference: Calculate the temperature deflection effect caused when there is a temperature difference between the main cable / stayed cable and the main beam. It is recommended that the cable-beam temperature difference be taken as 10℃.

4. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, Based on the integrated finite element model of line-bridge-pier, temperature load and train load are applied to analyze the mechanical behavior under different load conditions, specifically including: Train load condition analysis includes: Train loads at different locations were applied to the finite element model, and the longitudinal force of the rail and the displacement of the rail and beam surface were extracted after the loading calculation.

5. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, Based on the results of mechanical behavior analysis, pre-set load combination conditions were established to perform strength and stability checks on the seamless track within the main bridge area, specifically including: Seamless circuit strength calculation, including: Calculate the combined rail stress and compare it with the allowable rail stress [σ] to determine whether the combined stress is less than or equal to the allowable stress [σ]. The formula is as follows: In the formula: σ d For the dynamic bending stress of the rail; σ t This represents the maximum temperature stress of the rail. σ ss Additional stress caused by the expansion and contraction of the bridge due to overall temperature rise and fall; σ wn Additional stress caused by temperature deflection due to temperature difference in the cable beam; σ ln Add stress to the train's flexural deformation; σ Z For train traction (braking) stress; σ s The yield strength of the rail steel; [σ] represents the allowable stress of the rail; K is the safety factor; If the calculated combined stress is less than or equal to the allowable stress [σ], then the strength requirement is met.

6. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, Based on the results of mechanical behavior analysis, pre-set load combination conditions were established to perform strength and stability checks on the seamless track within the main bridge area, specifically including: Seamless circuit stability calculation includes: Calculate the allowable temperature rise of seamless track on a suspension bridge: In the formula: Temperature rise is permissible for seamless circuits; E is the elastic modulus of the rail; α is the coefficient of linear expansion of the rail; F is the cross-sectional area of ​​the rail; The allowable temperature and pressure for the two rails; P ss Additional stress caused by the expansion and contraction of the bridge due to overall temperature rise and fall; P wn Additional stress caused by temperature deflection due to temperature difference in the cable beam; P ln Add stress to the train's flexural deformation; Calculate the allowable temperature rise Compared with the actual temperature rise in the local area, if the temperature rise is allowed... If the temperature rise is greater than the actual temperature increase, the stability requirement is met; otherwise, there is a risk of instability.

7. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, If the calculation results do not meet the specifications, the line design scheme will be adjusted, specifically including: If the calculation results do not meet the specifications, adjustments will be made, including adjusting the locking rail temperature, installing low-resistance fasteners, or setting rail expansion joints. The modeling and analysis will then be repeated until both strength and stability meet the specifications.

8. The seamless track design method for a high-pier, ultra-long-span suspension bridge as described in claim 1, characterized in that, The method further includes: Based on different sections of the main bridge, including the main tower area, mid-span area, main beam transition area, and beam end area, the rail stress distribution, average stress level, and stress envelope characteristics under the most unfavorable load combination (i.e., combined stress) are analyzed. The rail locking temperature of the rails in different sections of the main bridge is then differentially optimized and adjusted to make the tensile stress and compressive stress of the rails tend to be balanced under normal operating conditions, thereby extending the service life of the rails.

9. A seamless track design system for a high-pier, ultra-long-span suspension bridge, characterized in that, The system includes: The finite element modeling module is used to create an integrated finite element model of the line-bridge-pier, including rails, sleepers, track bed, beams, supports, and piers / towers, based on bridge and track design parameters. The load condition analysis module is used to apply temperature loads and train loads to analyze the mechanical behavior under different load conditions based on the integrated finite element model of line-bridge-pier. The seamless track calculation module is used to perform strength and stability calculations on the seamless track within the main bridge area based on the results of mechanical behavior analysis and to establish preset load combination conditions. If the calculation results do not meet the specifications, the track design scheme will be adjusted.

10. A seamless track design system for a high-pier, ultra-long-span suspension bridge according to claim 9, characterized in that, The system also includes: The rail temperature optimization module is used to optimize the rail temperature in different sections of the main bridge, including the main tower area, mid-span area, main beam transition area, and beam end area, based on the stress distribution, average stress level, and stress envelope characteristics of the rail under the most unfavorable load combination, i.e., combined stress. This allows the tensile and compressive stresses of the rail to tend to be balanced under normal operating conditions, thereby extending the service life of the rail.

Images