A method for quickly evaluating safety of vehicle driving on bridge under earthquake action

Abstract

The application discloses a kind of bridge on seismic action under the safety of vehicle fast evaluation method, comprising the following steps: establishing track-beam structure calculation model;Establishing bridge substructure calculation model;Establishing support connecting system calculation model, and connecting track-beam structure calculation model and bridge substructure calculation model;Establishing seismic wave simulation calculation module;Based on track-beam structure calculation model, bridge substructure calculation model, support connecting system calculation model and seismic wave simulation calculation module, track dynamic response is calculated;According to track dynamic response, the safety of vehicle under the earthquake is evaluated.This application fills the technical gap of the safety of vehicle under the earthquake without relying on bridge coupling simulation analysis for bridge on fast evaluation method.This application can realize ordinary design personnel in engineering design using the new index of the safety of vehicle under the earthquake newly proposed by this application to quickly analyze seismic action vehicle safety analysis.

Description

Technical Field

[0001] This invention belongs to the technical field of earthquake traffic safety evaluation for bridge engineering in the transportation industry, specifically relating to a rapid evaluation method for traffic safety on bridges under seismic loading. Background Technology

[0002] To ensure the smoothness and stability of the railway line, high-speed railways may construct viaducts stretching for thousands or even tens of kilometers, significantly increasing the probability that a train will be on one of these bridges during an earthquake. Even if the bridge structure itself remains intact during an earthquake, trains traveling on it may become unstable due to excessive vibration. Therefore, the dynamic response of bridge structures under seismic loads and its impact on train safety have attracted considerable attention from scholars worldwide, especially with the increasing use of viaducts in railway structures and the continuous improvement of train speeds.

[0003] Previously, assessing the safety of train operation on high-speed railway bridges required vehicle-bridge coupled simulation analysis, with the derailment coefficient being the primary criterion. However, in engineering applications, designers typically lack the resources to perform vehicle-bridge coupled simulations. Therefore, even derailment indicators like the derailment coefficient, which are easily calculated in almost any vehicle-bridge coupled simulation program, are difficult to obtain during engineering design.

[0004] Therefore, in order to address the above problems and solve the difficulty for ordinary designers in performing vehicle-bridge coupling simulation in engineering design, it is necessary to study a completely new evaluation method that does not rely on vehicle-bridge coupling simulation analysis, propose a new set of indicators that can be used to evaluate the safety of vehicles traveling on bridges under seismic loading, and conduct rapid evaluation of the safety of vehicles traveling on bridges under seismic loading. Summary of the Invention

[0005] This invention is proposed to address the problems existing in the prior art, and its purpose is to provide a rapid evaluation method for the safety of traffic on bridges under seismic loading.

[0006] The technical solution of this invention is: a method for rapid evaluation of traffic safety on bridges under seismic loading, comprising the following steps:

[0007] A. Establish a calculation model for the track-beam structure;

[0008] B. Establish a calculation model for the bridge substructure;

[0009] C. Establish a calculation model for the support connection system and connect it with the calculation model for the track-beam structure and the calculation model for the bridge substructure;

[0010] D. Establish a seismic wave simulation calculation module;

[0011] E. Based on the track-beam structure calculation model, the bridge substructure calculation model, the bearing connection system calculation model, and the seismic wave simulation calculation module, the track dynamic response is calculated.

[0012] F. Calculate and evaluate the safety of train operation on the bridge under seismic loading based on the track dynamic response.

[0013] Furthermore, step A establishes a calculation model for the track-beam structure, the specific process of which is as follows:

[0014] First, the track-beam structure is meshed to obtain information for each element;

[0015] Then, a variable cross-section beam element system was used to simulate each element;

[0016] Next, assign section properties to the two end sections of each unit, using arbitrary section properties as input.

[0017] Next, after obtaining the end section information of the element, the section properties are calculated, and the section properties are substituted into the element properties of the variable cross-section beam element.

[0018] Finally, all units of the track-beam structure are integrated to obtain a complete calculation model of the track-beam structure.

[0019] Furthermore, the input of the arbitrary cross-sectional characteristics is specifically carried out as follows:

[0020] First, input each side counterclockwise, separated by semicolons ";".

[0021] Then, the information for each edge contains 5 parameters, separated by commas, ";

[0022] Finally, the physical meanings of the five parameters are as follows:

[0023] ① Section number, >0 for outer contour, <0 for inner contour;

[0024] ② The x-coordinate of the starting endpoint;

[0025] ③ The z-coordinate of the starting endpoint;

[0026] ④ Radius r, = 0 for a straight line segment, > 0 for the radius of a circular arc;

[0027] ⑤ Arc markings: =0 = full circle, >0 = minor arc, <0 = major arc.

[0028] Furthermore, step F calculates and evaluates the safety of vehicles traveling on the bridge under seismic loading based on the track dynamic response. The specific process is as follows:

[0029] First, calculate the apparent orbital distortion rate (AVD) at any position and at any time. The calculation formula is as follows:

[0030]

[0031] In the formula, the symbol U represents the displacement of the line or track under seismic action; the symbol t represents the time when the deformation of the line or track occurs; and the symbol v represents the apparent track deformation rate at any displacement and any time, the value of which is equal to Calculated value; symbol V represents the train speed; symbol This indicates that the line has a horizontal velocity under seismic loading, i.e., the local velocity; the symbol h indicates the location of the deformed surface of the line or track; the symbol... This refers to the convective speed generated when a train travels on a track due to unevenness in the track itself and track deterioration caused by an earthquake.

[0032] Then, quickly assess driving safety using the following rules:

[0033] f1. The apparent orbital distortion rate v at any position and time is calculated according to formula (5), and the value is compared with the apparent orbital distortion rate limit [v].

[0034] f2. When v≥[v], the risk of derailment is relatively high, and the further away from [v], the higher the risk of derailment.

[0035] f3. When v < [v], the risk of derailment is low, and the closer to 0, the lower the risk of derailment.

[0036] In the formula, the symbol [v] represents the apparent track deformation rate limit. After testing and simulation verification, the apparent track deformation rate limit can be taken as [v] = 1.0.

[0037] Furthermore, step B involves establishing a calculation model for the bridge's substructure, the specific process of which is as follows:

[0038] First, the substructure of the bridge is meshed to obtain information for each element, and each element is simulated using elasto-plastic fiber beam-column elements;

[0039] Then, section properties are assigned to the two end sections of each unit. Arbitrary section properties are used for input, and the section information includes information on reinforcing bars or prestressed tendons.

[0040] Next, after obtaining the end section information of the element, calculate the section properties and substitute the section properties into the element properties of the variable cross section beam element. The calculated section properties should include the influence of steel bars or prestressing tendons on the section properties.

[0041] Finally, all units of the bridge substructure are integrated to obtain a complete calculation model of the bridge substructure.

[0042] Furthermore, the simulation process of the bridge substructure using elasto-plastic fiber beam-column elements also includes the following steps:

[0043] First, the bridge substructure concrete and pier reinforcement are respectively given constitutive models corresponding to concrete fibers and steel bars or prestressed tendon fibers.

[0044] Then, the concrete fiber of the bridge substructure was simulated using the Kent-Scott-Park concrete constitutive model, or using a concrete constitutive model obtained from experimental data.

[0045] Finally, the reinforcing steel or prestressed tendon fibers of the bridge substructure can be simulated using the modified Menegato and Pinto models, or by using a constitutive model of the reinforcing steel or prestressed tendon obtained from experimental data.

[0046] Furthermore, step C establishes a calculation model for the support connection system and connects it with the track-beam structure calculation model and the bridge substructure calculation model. The specific process is as follows:

[0047] First, determine the type of support to be simulated in the support connection system;

[0048] Then, select the calculation model corresponding to the support type;

[0049] Finally, the calculation model of the track-beam structure and the calculation model of the bridge substructure are connected using the calculation model of the support connection system.

[0050] Furthermore, step D establishes the seismic wave simulation calculation module, the specific process of which is as follows:

[0051] First, a seismic wave simulation calculation module is established by using artificially synthesized seismic waves or selecting similar seismic waves from a seismic wave database;

[0052] Then, the random seismic waves calculated by the seismic wave simulation module are substituted into the bridge substructure calculation model established in step B.

[0053] Furthermore, step E, based on the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation calculation module, calculates the track dynamic response. The specific process is as follows:

[0054] First, using the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation calculation module, and relying on the dynamic module of the finite element system, we conducted dynamic response analysis under the action of seismic waves.

[0055] Then, the orbital dynamic response parameters, such as the orbital deformation, are extracted from the two end nodes of any element on the orbital structure at each calculation time of the seismic wave.

[0056] The beneficial effects of this invention are as follows:

[0057] This invention establishes a rapid evaluation method for the safety of vehicles traveling on bridges under seismic loading, filling the technical gap in rapid evaluation methods for the safety of vehicles traveling on bridges under seismic loading that do not rely on vehicle-bridge coupling simulation analysis.

[0058] This invention provides a rapid evaluation method for traffic safety in the field of seismic driving analysis of bridge engineering in the transportation industry. Using this invention, ordinary designers can quickly analyze traffic safety under seismic loads on bridges by utilizing the new traffic safety indicators proposed in this invention. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the steps of the present invention;

[0060] Figure 2 This is a schematic diagram of the end section of the beam structure in this invention;

[0061] Figure 3 This is a schematic diagram of the input interface for the end section of the beam structure in this invention;

[0062] Figure 4 This is a schematic diagram illustrating the calculation of apparent deformation rate (with a ground peak acceleration amplitude of 0.2g and a vehicle speed of 350km / h) based on a vehicle-free track-bridge structure in this invention.

[0063] Figure 5 This is a schematic diagram illustrating the calculation of apparent deformation rate (with a ground peak acceleration amplitude of 0.3g and a vehicle speed of 250km / h) based on a vehicle-free track-bridge structure in this invention.

[0064] Figure 6 This is a schematic diagram of the calculation of apparent deformation rate based on a vehicleless track-bridge structure in this invention (with a ground peak acceleration amplitude of 0.3g and a vehicle speed of 350km / h). Detailed Implementation

[0065] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0066] like Figures 1 to 6 As shown, a rapid evaluation method for traffic safety on bridges under seismic loading includes the following steps:

[0067] A. Establish a calculation model for the track-beam structure;

[0068] B. Establish a calculation model for the bridge substructure;

[0069] C. Establish a calculation model for the support connection system and connect it with the calculation model for the track-beam structure and the calculation model for the bridge substructure;

[0070] D. Establish a seismic wave simulation calculation module;

[0071] E. Based on the track-beam structure calculation model, the bridge substructure calculation model, the bearing connection system calculation model, and the seismic wave simulation calculation module, the track dynamic response is calculated.

[0072] F. Calculate and evaluate the safety of train operation on the bridge under seismic loading based on the track dynamic response.

[0073] Step A involves establishing a calculation model for the track-beam structure. The specific process is as follows:

[0074] First, the track-beam structure is meshed to obtain information for each element;

[0075] Then, a variable cross-section beam element system was used to simulate each element;

[0076] Next, assign section properties to the two end sections of each unit, using arbitrary section properties as input.

[0077] Next, after obtaining the end section information of the element, the section properties are calculated, and the section properties are substituted into the element properties of the variable cross-section beam element.

[0078] Finally, all units of the track-beam structure are integrated to obtain a complete calculation model of the track-beam structure.

[0079] The specific process for inputting the arbitrary cross-sectional properties is as follows:

[0080] First, input each side counterclockwise, separated by semicolons ";".

[0081] Then, the information for each edge contains 5 parameters, separated by commas, ";

[0082] Finally, the physical meanings of the five parameters are as follows:

[0083] ① Section number, >0 for outer contour, <0 for inner contour;

[0084] ② The x-coordinate of the starting endpoint;

[0085] ③ The z-coordinate of the starting endpoint;

[0086] ④ Radius r, = 0 for a straight line segment, > 0 for the radius of a circular arc;

[0087] ⑤ Arc markings: =0 = full circle, >0 = minor arc, <0 = major arc.

[0088] Specifically, in step A, the above-mentioned arbitrary cross-section input rule is used for, for example... Figure 2 The beam structure end section shown adopts Figure 3 The input interface shown allows you to input the contour information of the beam structure's end section. Specific data can be found in Table 1.

[0089] Table 1 Input data for box girder cross-section

[0090]

[0091]

[0092] Step F calculates and evaluates the safety of vehicles traveling on the bridge under seismic loading based on the track dynamic response. The specific process is as follows:

[0093] First, calculate the apparent orbital distortion rate (AVD) at any position and at any time. The calculation formula is as follows:

[0094]

[0095] In the formula, the symbol U represents the displacement of the line or track under seismic action; the symbol t represents the time when the deformation of the line or track occurs; and the symbol v represents the apparent track deformation rate at any displacement and any time, the value of which is equal to Calculated value; symbol V represents the train speed; symbol This indicates that the line has a horizontal velocity under seismic loading, i.e., the local velocity; the symbol h indicates the location of the deformed surface of the line or track; the symbol... This refers to the convective speed generated when a train travels on a track due to unevenness in the track itself and track deterioration caused by an earthquake.

[0096] Then, quickly assess driving safety using the following rules:

[0097] f1. The apparent orbital distortion rate v at any position and time is calculated according to formula (5), and the value is compared with the apparent orbital distortion rate limit [v].

[0098] f2. When v≥[v], the risk of derailment is relatively high, and the further away from [v], the higher the risk of derailment.

[0099] f3. When v < [v], the risk of derailment is low, and the closer to 0, the lower the risk of derailment.

[0100] In the formula, the symbol [v] represents the apparent track deformation rate limit. After testing and simulation verification, the apparent track deformation rate limit can be taken as [v] = 1.0.

[0101] Step B involves establishing a calculation model for the bridge substructure. The specific process is as follows:

[0102] First, the substructure of the bridge is meshed to obtain information for each element, and each element is simulated using elasto-plastic fiber beam-column elements;

[0103] Then, section properties are assigned to the two end sections of each unit. Arbitrary section properties are used for input, and the section information includes information on reinforcing bars or prestressed tendons.

[0104] Next, after obtaining the end section information of the element, calculate the section properties and substitute the section properties into the element properties of the variable cross section beam element. The calculated section properties should include the influence of steel bars or prestressing tendons on the section properties.

[0105] Finally, all units of the bridge substructure are integrated to obtain a complete calculation model of the bridge substructure.

[0106] The simulation of the bridge substructure using elasto-plastic fiber beam-column elements also includes the following processes:

[0107] First, the bridge substructure concrete and pier reinforcement are respectively given constitutive models corresponding to concrete fibers and steel bars or prestressed tendon fibers.

[0108] Then, the concrete fiber of the bridge substructure was simulated using the Kent-Scott-Park concrete constitutive model, or using a concrete constitutive model obtained from experimental data.

[0109] Finally, the reinforcing steel or prestressed tendon fibers of the bridge substructure can be simulated using the modified Menegato and Pinto models, or by using a constitutive model of the reinforcing steel or prestressed tendon obtained from experimental data.

[0110] More specifically, in step B, the stress-strain curve equation for the Kent-Scott-Park concrete constitutive model of the bridge substructure can be written as:

[0111]

[0112] In the formula, σ and ε represent the stress and strain of the concrete.

[0113] f co The compressive strength (peak stress) of concrete.

[0114] ε co This represents the compressive strain (peak stress) of concrete corresponding to its compressive strength.

[0115] f cu The ultimate stress is the failure strength of concrete.

[0116] ε cu This represents the compressive strain (ultimate strain) of concrete corresponding to the failure strength.

[0117] More specifically, for the modified Menegato and Pinto constitutive models of steel bars or prestressed tendons, the stress-strain curve equation can be written as:

[0118]

[0119] in:

[0120]

[0121] In the formula, σ * ε * The calculated stress and strain values ​​are for the reinforcing steel fibers.

[0122] σ and ε represent the stress and strain of the steel reinforcement fibers;

[0123] (ε r , σ r ) represents the unloading point location, which is assumed to be (0,0) in the elastic state;

[0124] (ε0, σ0) is the intersection of the two asymptotes (elastic and yield asymptotes) of the loading or unloading path;

[0125] b is the stiffness reduction rate;

[0126] R is a parameter that takes into account the Bauschinger effect;

[0127] R0, α1, and α2 are constants (parameters that determine the state of the curve, and can be optimized values ​​obtained from experiments);

[0128] ξ is the difference (absolute value) between the maximum strain and ε0 in the loading / unloading direction.

[0129] Step C establishes the calculation model of the support connection system and connects the track-beam structure calculation model and the bridge substructure calculation model. The specific process is as follows:

[0130] First, determine the type of support to be simulated in the support connection system;

[0131] Then, select the calculation model corresponding to the support type;

[0132] Finally, the calculation model of the track-beam structure and the calculation model of the bridge substructure are connected using the calculation model of the support connection system.

[0133] Step D establishes the seismic wave simulation calculation module. The specific process is as follows:

[0134] First, a seismic wave simulation calculation module is established by using artificially synthesized seismic waves or selecting similar seismic waves from a seismic wave database;

[0135] Then, the random seismic waves calculated by the seismic wave simulation module are substituted into the bridge substructure calculation model established in step B.

[0136] Specifically, in step D, the two methods of artificially synthesizing seismic waves or selecting similar seismic waves from a seismic wave database are used as the main methods for the seismic wave simulation calculation module, thereby forming the seismic wave simulation calculation module.

[0137] Seismic waves are often synthesized using the trigonometric series method, and the calculation formula is as follows:

[0138]

[0139] In the formula, These are artificially synthesized seismic waves;

[0140] f(t) is the strength envelope;

[0141] C k ω k These are the amplitude and frequency of the k-th frequency component, respectively;

[0142] Let be a random phase angle uniformly distributed within the interval (0, 2π).

[0143] The natural seismic wave adjustment method mainly adjusts three aspects: intensity, frequency, and duration. Natural seismic waves are selected using the "two-band dual-index method" and the "two-band dual-index + 70% energy duration method".

[0144] Step E, based on the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation calculation module, calculates the track dynamic response. The specific process is as follows:

[0145] First, using the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation calculation module, and relying on the dynamic module of the finite element system, we conducted dynamic response analysis under the action of seismic waves.

[0146] Then, the orbital dynamic response parameters, such as the orbital deformation, are extracted from the two end nodes of any element on the orbital structure at each calculation time of the seismic wave.

[0147] Specifically, if step C involves a novel, specially designed support, the specific calculation model corresponding to that support can be determined based on the experimental results.

[0148] Specifically, in step E, dynamic response analysis under seismic wave action is performed using the dynamic module of the autonomous finite element Wolong system.

[0149] Another embodiment

[0150] This invention was incorporated into the independently developed railway bridge finite element digital twin computing platform (Wolong). To demonstrate the superiority and engineering application of the rapid evaluation method for bridge traffic safety under seismic loading, an engineering example was designed. Friction pendulum bearings were installed on a high-speed railway bridge, with the bridge pier height set to 30 meters. The seismic motion used was RSN825, with ground peak ground acceleration amplitudes of 0.2g and 0.3g. Train speeds were set to 250 km / h and 350 km / h. The calculation results are as follows: Figures 4-6 As shown in the figure, the apparent distortion rate calculation is based on the vehicleless track-bridge structure of the present invention.

[0151] according to Figure 4 As shown, when the ground peak acceleration is only 0.2g, even if the train speed reaches 350 km / h, its apparent deformation rate peak does not exceed 0.8m / s, which is far less than the safety limit of 1m / s.

[0152] When the peak ground acceleration increases to 0.3g, a train traveling at 350 km / h faces a high risk of derailment. For example... Figure 6 As shown, the apparent distortion rate surface has locally exceeded the safety limit of 1 m / s. According to equation (5), reducing the driving speed can reduce the amplitude of the apparent distortion rate surface. Therefore, reducing the driving speed to 250 km / h, as... Figure 5 As shown, the peak value of the apparent deformation rate surface is significantly lower than that at 350 km / h, and is within the safe limit of 1 m / s.

[0153] The above results also illustrate the importance of rapid braking and deceleration of trains during an earthquake in preventing derailment.

[0154] Another embodiment

[0155] To demonstrate the accuracy and reliability of the rapid evaluation method for bridge traffic safety under seismic loading, the same engineering example was used to compare and analyze the derailment coefficient corresponding to the new index of this invention and the traditional vehicle-bridge coupling simulation analysis. Two indicators, event misjudgment rate and working condition misjudgment rate, were also introduced for analysis. The relevant explanations are as follows.

[0156] The derailment coefficient corresponding to traditional vehicle-bridge coupling simulation analysis is widely used to predict derailment. The current national standard "Specification for Evaluation and Testing of Dynamic Performance of Locomotives and Rolling Stock" (GB / T5599-2019) stipulates that the limit value of the derailment coefficient of locomotives is 0.8, while its historical version "Specification for Evaluation and Testing of Dynamic Performance of Railway Vehicles" (GB5599-85) stipulates that the allowable limit value and the dangerous limit value of the derailment coefficient are 1.0 and 1.2, respectively.

[0157] Predicting derailment events using indicators such as the derailment coefficient or the newly proposed "apparent track deformation rate" ("apparent deformation rate") instead of directly simulating the entire process will inevitably lead to a certain degree of misjudgment. For situations where derailment has not actually occurred, the misjudgment rate reflects the conservatism of the corresponding indicator. The higher the misjudgment rate, the more conservative the indicator tends to be, i.e., the less accurate it is.

[0158] The following introduces two indicators for evaluating reliability: event misjudgment rate and operating condition misjudgment rate, explained as follows:

[0159] The event misjudgment rate represents the proportion of misjudging a train derailment out of the total number of train events, as shown in Equation (6). The working condition misjudgment rate represents the proportion of misjudging an earthquake derailment out of the total number of earthquake working conditions, as shown in Equation (7).

[0160]

[0161]

[0162] In the formula, P e and P c These represent the event misjudgment rate and the operating condition misjudgment rate, respectively. and These represent the total number of events that did not actually derail and the total number of operating conditions that did not actually derail; and These represent the number of events that were actually not derailed and the number of events that were mistakenly identified as derailed by the derailment indicator during the actual operating conditions, respectively.

[0163] Table 2 shows a comparison between the event misjudgment rate and the working condition misjudgment rate for a certain actual test condition:

[0164] Table 2 shows the derailment evaluation index, which measures the misjudgment rate of actual non-derailment conditions or events as derailments.

[0165]

[0166] As shown in Table 2, whether assessing a single event or the entire operational condition, the misjudgment rate of derailment prediction using the apparent distortion rate of this invention is significantly lower than that using the derailment coefficient. The event misjudgment rate of the apparent distortion rate is less than 10%, while the event misjudgment rate of the derailment coefficient is approximately 40%, which confirms that the derailment coefficient has lower accuracy in determining whether a single train car has derailed.

[0167] According to the statistical results in the table, the misjudgment rate of the working condition is significantly higher than that of the event misjudgment rate. This is because a single earthquake working condition includes 16 train events, and if even one train is misjudged as derailed, the working condition is considered a misjudgment. A misjudgment rate of approximately 60% for the working condition means that it can hardly indicate the risk of train derailment under an earthquake, while the misjudgment rate for the working condition with a deformation rate remaining below 40% is significantly better than the derailment coefficient.

[0168] Comparing different bearing types, the misjudgment rate of friction pendulum bearings was higher than that of spherical steel bearings. This may be because derailment is a continuous process, while the peak apparent deformation rate only reflects the instantaneous adverse condition and does not consider the duration. Because friction pendulum bearings have self-resetting capabilities, the duration of severe track slippage is shorter, resulting in a shorter impact time on the vehicle and insufficient energy accumulation to derail the train. However, the accuracy of the apparent deformation rate is still significantly higher than that of the derailment coefficient.

[0169] This invention establishes a calculation model for the track-beam structure; a calculation model for the bridge substructure; a calculation model for the support connection system, and connects the track-beam structure calculation model and the bridge substructure calculation model; and establishes a seismic wave simulation module. Based on the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation module, the dynamic response of the track is calculated. Based on the track dynamic response, the safety of traffic on the bridge under seismic loading is calculated and evaluated. Therefore, a rapid evaluation method for the safety of traffic on bridges under seismic loading is established.

[0170] This invention provides a rapid evaluation method for bridge traffic safety under seismic loading in the field of seismic traffic safety evaluation technology for bridge engineering in the transportation industry. It solves the problem of relying on vehicle-bridge coupled simulation analysis to evaluate traffic safety under seismic loading in traditional engineering design, and can reduce the misjudgment rate of the traditional evaluation index "derailment coefficient".

Claims

1. A method for rapid evaluation of traffic safety on bridges under seismic loading, characterized in that: Includes the following steps: A. Establish a calculation model for the track-beam structure; B. Establish a calculation model for the bridge substructure; C. Establish a calculation model for the support connection system and connect it with the calculation model for the track-beam structure and the calculation model for the bridge substructure; D. Establish a seismic wave simulation calculation module; E. Based on the track-beam structure calculation model, the bridge substructure calculation model, the bearing connection system calculation model, and the seismic wave simulation calculation module, the track dynamic response is calculated. F. Calculate and evaluate the safety of train operation on the bridge under seismic loading based on the track dynamic response; Step B involves establishing a calculation model for the bridge substructure. The specific process is as follows: First, the substructure of the bridge is meshed to obtain information for each element, and each element is simulated using elasto-plastic fiber beam-column elements; Then, section properties are assigned to the two end sections of each unit. Arbitrary section properties are used for input, and the section information includes information on reinforcing bars or prestressed tendons. Next, after obtaining the end section information of the element, calculate the section properties and substitute the section properties into the element properties of the variable cross section beam element. The calculated section properties should include the influence of steel bars or prestressing tendons on the section properties. Finally, all units of the bridge substructure are integrated to obtain a complete calculation model of the bridge substructure. During the simulation of the bridge substructure using elasto-plastic fiber beam-column elements, Includes the following processes: First, the bridge substructure concrete and pier reinforcement are respectively given constitutive models corresponding to concrete fibers and steel bars or prestressed tendon fibers. Then, the concrete fiber of the bridge substructure was simulated using the Kent-Scott-Park concrete constitutive model, or using a concrete constitutive model obtained from experimental data. Finally, the reinforcing steel or prestressed tendon fibers of the bridge substructure can be simulated using the modified Menegato and Pinto models, or by using a constitutive model of the reinforcing steel or prestressed tendon obtained from experimental data.

2. The method for rapid evaluation of traffic safety on bridges under seismic loading as described in claim 1, characterized in that: Step A involves establishing a calculation model for the track-beam structure. The specific process is as follows: First, the track-beam structure is meshed to obtain information for each element; Then, a variable cross-section beam element system was used to simulate each element; Next, assign section properties to the two end sections of each unit, using arbitrary section properties as input. Next, after obtaining the end section information of the element, the section properties are calculated, and the section properties are substituted into the element properties of the variable cross-section beam element. Finally, all units of the track-beam structure are integrated to obtain a complete calculation model of the track-beam structure.

3. The method for rapid evaluation of traffic safety on bridges under seismic loading as described in claim 2, characterized in that: The specific process for inputting the arbitrary cross-sectional properties is as follows: First, input each side in a counter-clockwise direction, separated by semicolons ";"; Then, the information for each edge contains 5 parameters, separated by commas, "; Finally, the physical meanings of the five parameters are as follows: ① Section number, >0 for outer contour, <0 for inner contour; ② The x-coordinate of the starting endpoint; ③ The z-coordinate of the starting endpoint; ④ Radius r, = 0 for a straight line segment, > 0 for the radius of a circular arc; ⑤ Arc markings: =0 = full circle, >0 = minor arc, <0 = major arc.

4. The method for rapid evaluation of traffic safety on bridges under seismic loading as described in claim 1, characterized in that: Step F calculates and evaluates the safety of vehicles traveling on the bridge under seismic loading based on the track dynamic response. The specific process is as follows: First, calculate the apparent orbital distortion rate (AVD) at any position and at any time. The calculation formula is as follows: （5）； In the formula, the symbol This indicates the displacement of a railway line or track under seismic loading; the symbol 't' represents the time when the deformation of the line or track occurs; the symbol... The apparent orbital deformation rate represents the apparent orbital deformation rate at any displacement and any time, and its value is equal to... Calculated value; symbol Indicates the train's speed; symbol This indicates that the line has a horizontal velocity under seismic action, i.e., the local velocity; symbol Indicates the location of the deformed surface of the line or track; symbol This refers to the convective speed generated when a train travels on a track due to unevenness in the track itself and track deterioration caused by an earthquake. Then, quickly assess driving safety using the following rules: f1. The apparent orbital distortion rate at any position and time, calculated according to equation (5). Compare the numerical values ​​with the apparent orbital deformation rate limit. Compare; f2. When At that time, the risk of derailment is relatively high, and the further away from it... The higher the risk of derailment; f3. When At this point, the risk of derailment is low, and the closer it is to 0, the lower the risk of derailment. In the formula, the symbol This indicates the apparent track deformation rate limit. Through experimental and simulation verification, the value of the apparent track deformation rate limit can be determined according to... Values.

5. The method for rapid evaluation of traffic safety on bridges under seismic loading as described in claim 1, characterized in that: Step C establishes the calculation model of the support connection system and connects the track-beam structure calculation model and the bridge substructure calculation model. The specific process is as follows: First, determine the type of support to be simulated in the support connection system; Then, select the calculation model corresponding to the support type; Finally, the calculation model of the track-beam structure and the calculation model of the bridge substructure are connected using the calculation model of the support connection system.

6. The method for rapid evaluation of traffic safety on bridges under seismic loading as described in claim 1, characterized in that: Step D establishes the seismic wave simulation calculation module. The specific process is as follows: First, a seismic wave simulation calculation module is established by using artificially synthesized seismic waves or selecting similar seismic waves from a seismic wave database; Then, the random seismic waves calculated by the seismic wave simulation module are substituted into the bridge substructure calculation model established in step B.

7. The method for rapid evaluation of traffic safety on bridges under seismic loading as described in claim 1, characterized in that: Step E, based on the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation calculation module, calculates the track dynamic response. The specific process is as follows: First, using the track-beam structure calculation model, the bridge substructure calculation model, the support connection system calculation model, and the seismic wave simulation calculation module, and relying on the dynamic module of the finite element system, we conducted dynamic response analysis under the action of seismic waves. Then, the orbital dynamic response parameters, such as the orbital deformation, are extracted from the two end nodes of any element on the orbital structure at each calculation time of the seismic wave.

Images