Railway beam bridge post-earthquake track irregularity analysis method and system

Abstract

The invention discloses a post-earthquake track irregularity analysis method and system for a railway beam bridge, relates to the technical field of earthquake resistance, disaster prevention and disaster reduction of bridge engineering structures, and solves the problems that an existing integrated bridge-track analysis model is complex and repeated in modeling and time-consuming in analysis. The method comprises the following steps: simplifying a railway beam bridge analysis model into a bridge model and a beam track model of a track-free structure; the method comprises the following steps: step 1, establishing a bridge model of a track-free structure for nonlinear seismic analysis to obtain a girder seismic response; the seismic response of the main beam obtained based on seismic analysis in the step 1 serves as a displacement load and is applied to the beam-rail model to obtain steel rail deformation; calculating the irregularity of the railway bridge track after the earthquake based on the steel rail deformation in the step 2; according to the characteristics of rail damage under the earthquake action of the railway beam bridge, aiming at the defects of the existing integrated bridge-rail analysis model, a reasonable rail irregularity simplified calculation method is provided, and rapid analysis of the post-earthquake irregularity of the railway beam bridge is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of earthquake-resistant disaster prevention and mitigation of bridge engineering structures, and in particular relates to a method and system for analyzing post-earthquake track irregularities of a railway beam bridge. Background Art

[0002] At present, the seismic design of railway projects in my country mainly focuses on structural safety. There is a lack of systematic research on the performance of track structures under earthquakes, which directly affects the safety of train traffic. Track irregularities are one of the important excitation sources and static control indicators of high-speed train vibrations. Therefore, it is crucial to quickly obtain the deformation state of the track under earthquakes to evaluate the functional status of railway bridges.

[0003] The Code for Seismic Design of Railway Engineering (GB 50111-2006 (2009 Edition)) adopts simplified calculation for railway bridge track system, without considering track structure, and cannot directly analyze the seismic response of track structure under earthquake. At the same time, the existing integrated bridge-track analysis method requires the establishment of a complex track model, and each bridge needs to repeatedly model the track structure, which has problems such as complex and repeated modeling and high calculation time cost, and is not suitable for promotion and application in actual engineering. Summary of the invention

[0004] In view of this, the present invention provides a method and system for analyzing post-earthquake track irregularity of railway beam bridges to solve the problem in the prior art that the integrated bridge-track analysis method needs to establish a complex track model and each bridge needs to repeatedly model the track structure, resulting in complex and repetitive modeling, high calculation time cost, and is not suitable for promotion and application in actual engineering.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for analyzing track irregularity of railway beam bridge after earthquake, comprising:

[0007] Step 1: Establish a nonlinear finite element analysis model of the trackless bridge, and obtain the seismic response of the main beam based on the nonlinear finite element analysis model of the trackless bridge;

[0008] The step 1 specifically includes:

[0009] Step 1.1: Considering the nonlinearity of supports and piers, a nonlinear finite element analysis model of trackless bridge is established;

[0010] Step 1.2: Input seismic waves into the nonlinear finite element analysis model of the trackless bridge and perform nonlinear time history analysis to obtain the seismic response of the main beam.

[0011] The main beam seismic response includes relative peak displacement and residual displacement of adjacent main beam ends at each main beam expansion joint.

[0012] Step 2: Establishing a beam-rail nonlinear finite element model, wherein the beam-rail nonlinear finite element model obtains rail deformation based on the seismic response of the main beam obtained in step 1;

[0013] The step 2 comprises:

[0014] Step 2.1: Establish a beam-rail nonlinear finite element model based on the establishment rules;

[0015] In step 2.1, the establishment of rules includes:

[0016] The beam-track nonlinear finite element model includes the main beam and track structure. A certain span must be considered to ensure the restraint force of the track on the main beam under earthquake action. The span of a single main beam is ≥5m.

[0017] The main beam is set with a fixed side and a displacement loading side to simulate the seismic displacement behavior at the expansion joint of the main beam. The fixed side constrains the translation and rotation of the main beam, and the loading side main beam is not constrained;

[0018] The main beam is modeled using beam elements, the track structure needs to consider the nonlinear mechanical characteristics of fasteners and rails, and other components are simulated using elastic elements.

[0019] Step 2.2: The relative peak displacement and residual displacement obtained in step 1.2 are input as loads into the beam-rail nonlinear finite element model and applied to the main beam on the loading side. After the displacement loading is completed, the displacement of the main beam on the loading side is unloaded to the residual displacement size, and the displacement of the rail after unloading is recorded.

[0020] Step 3: Based on the rail deformation calculation in step 2, the unevenness of the railway bridge track after the earthquake is obtained.

[0021] The step 3 comprises:

[0022] According to the rail deformation obtained in step 2, the track irregularity value is calculated using the chord measurement method (10m), as shown in formula (1).

[0023] V i ≈V i ′=H i -(H i-a +H i+a ) / twenty one)

[0024] Where: V i 、V i ′ is the track irregularity value; H i-a , H i , H i+a They are the distances that the starting point, midpoint and end point of the rail chord measure deviate from the original displacement.

[0025] A railway beam bridge post-earthquake track irregularity analysis system, comprising:

[0026] Trackless bridge model building module: build a nonlinear finite element analysis model of the trackless bridge, and obtain the seismic response of the main beam based on the nonlinear finite element analysis model of the trackless bridge;

[0027] Beam-rail model building module: building a beam-rail nonlinear finite element model, wherein the beam-rail nonlinear finite element model obtains rail deformation based on the seismic response of the main beam obtained in step 1;

[0028] Calculation module: Based on the rail deformation calculation in step 2, the post-earthquake railway bridge track irregularity value is obtained.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] The present invention proposes a reasonable post-earthquake track irregularity analysis method for railway beam bridges, simplifies the integrated bridge-track into a trackless bridge model and a beam-track model. The beam-track model can be applied to the track irregularity analysis of the same type of railway beam bridges, avoids repeated modeling of track structure during the analysis process, saves modeling and calculation analysis time, effectively improves analysis efficiency, and is convenient for bridge design engineers to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0032] Figure 1 The nonlinear finite element analysis model of the trackless bridge involved in Example 1;

[0033] Figure 2 The nonlinear time history analysis seismic wave involved in Example 1;

[0034] Figure 3 The relative displacement time history diagram of the main beam end at the expansion joint of the finite element model in Example 1;

[0035] Figure 4 is the beam-rail nonlinear finite element model involved in Example 1;

[0036] Figure 5 The displacement of the rail after unloading of the beam-rail nonlinear finite element model involved in Example 1;

[0037] Figure 6 A schematic diagram of calculating track irregularity using the chord measurement method involved in Example 1;

[0038] Figure 7 It is a schematic diagram of the process structure of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0044] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0045] Example 1

[0046] like Figure 1-Figure 6 As shown, the embodiment of the present invention discloses step 1: establishing a nonlinear finite element analysis model of the trackless bridge, and obtaining the seismic response of the main beam based on the nonlinear finite element analysis model of the trackless bridge;

[0047] The step 1 specifically includes:

[0048] Step 1.1: Considering the nonlinearity of supports and piers, a nonlinear finite element analysis model of trackless bridge is established;

[0049] In the process of model establishment, elastic beam-column element simulation (Elastic Beam-Column Element) is used; for reinforced concrete piers that may suffer plastic failure, nonlinear fiber beam-column element simulation (Nonlinear Beam-Column Element) is used, and the steel bars are assigned Steel02 material and the concrete is assigned Kent-Part material. The bearing exhibits bilinear mechanical behavior characteristics in the sliding direction. In the fixed direction, the difference in the mechanical properties of the bearing before and after the failure of the limiting shear nail is considered. Therefore, the linear elastic constitutive model is used for the bearing before failure, and the bilinear constitutive model is the same as the sliding direction after failure. For detailed information on the nonlinear finite element analysis model and material constitutive model of trackless bridges, see Figure 1 .

[0050] Step 1.2: Input seismic waves into the nonlinear finite element analysis model of the rail bridge, and perform nonlinear time history analysis to obtain the seismic response of the main beam.

[0051] The main beam seismic response includes relative peak displacement and residual displacement of adjacent main beam ends at each main beam expansion joint.

[0052] Select a natural recorded seismic wave from the Pacific Earthquake Engineering Research (PEER), and the seismic wave time history curve is as follows: Figure 2 As shown in the figure, the nonlinear time history analysis is carried out by inputting the bridge transverse direction into the bridge refined model, and the relative displacement time history of the main beam end at the expansion joint of the finite element model is extracted, as shown in the figure. Figure 3 As shown in Figure 1, #0 to #5 are the main beam displacements of the six beam peaks. The results show that the relative peak displacement and residual displacement of the main beam at the beam joints of abutments #0 and #5 are larger, while the relative peak displacement and residual displacement of the main beam at the beam joints of piers #1 to #4 are smaller. The relative peak displacement and residual displacement of the main beam are shown in Table 1.

[0053] Table 1 Relative peak value and residual displacement of beam joint main beam

[0054]

[0055] Step 2: Establishing a beam-rail nonlinear finite element model, wherein the beam-rail nonlinear finite element model obtains rail deformation based on the seismic response of the main beam obtained in step 1;

[0056] The step 2 comprises:

[0057] Step 2.1: Establish a beam-rail nonlinear finite element model based on the establishment rules;

[0058] The nonlinearity of the base plate, track plate, sleeper rails and main beam of the track structure is not considered and is simulated using beam units; the fasteners and rails are vulnerable components and are given elastic-plastic constitutive materials (actual bridge earthquake damage phenomena show that the components of the track structure that are prone to damage are mainly fasteners and rails. Therefore, their nonlinear characteristics need to be considered in the refined analysis model to reflect the nonlinear mechanical behavior of the track structure under earthquake action, which has a great impact on the analysis results). The single-sided main beam is 12.98m long and has a gap of 0.1m. The horizontal and rotational degrees of freedom are constrained at the bottom of the fixed-side main beam, and the degrees of freedom on the sliding side are not constrained. The beam-track model is as follows: Figure 4 shown.

[0059] In step 2.1, the establishment of rules includes:

[0060] The beam-track nonlinear finite element model includes the main beam and track structure. A certain span must be considered to ensure the restraint force of the track on the main beam under earthquake action. The span of a single main beam is ≥5m.

[0061] The main beam is set with a fixed side and a displacement loading side to simulate the seismic displacement behavior at the expansion joint of the main beam. The fixed side constrains the translation and rotation of the main beam, and the loading side main beam is not constrained;

[0062] The main beam is modeled using beam elements, the track structure needs to consider the nonlinear mechanical characteristics of fasteners and rails, and other components are simulated using elastic elements.

[0063] Step 2.2: Apply the peak displacement of the main beam obtained in step 1 (12cm, 4cm, 6cm, 4cm, 3cm, 12cm) to the main beam on the loading side. After the displacement loading is completed, the displacement of the main beam on the loading side is unloaded to the residual displacement (9cm, 1cm, 2cm, 3cm, 0cm, 8cm) respectively, and record the displacement of the rail after unloading. The results are as follows: Figure 5 shown.

[0064] Step 3: Based on the rail deformation calculation in step 2, the unevenness of the railway bridge track after the earthquake is obtained.

[0065] The step 3 comprises:

[0066] According to the rail deformation obtained in step 2, the track irregularity values ​​under earthquake action are obtained respectively with reference to the requirements of the static track irregularity index of the "Rules for Repair of Conventional Railway Lines" (TG-GW102-2019). The track irregularity is generally analyzed and calculated using the chord measurement method (L = 10m). The chord measurement method is as follows: Figure 6 As shown:

[0067] The calculation refers to formula (1).

[0068] V i ≈V i ′=H i-(H i-a +H i+a ) / twenty one)

[0069] Where: V i 、V i ′ is the track irregularity value; H i-a , H i , H i+a They are the distances that the starting point, midpoint and end point of the rail chord measure deviate from the original displacement.

[0070] Under the action of seismic waves, the track irregularity values ​​of beam expansion joints #0 to #5 are shown in Table 2. The track irregularity value of the railway beam bridge after the earthquake is 44 mm. The above is the analysis of the specific embodiment.

[0071] Table 2 Beam joint irregularity values

[0072]

[0073] Example 2

[0074] This embodiment provides a railway beam bridge post-earthquake track irregularity analysis system, comprising:

[0075] Trackless bridge model building module: build a nonlinear finite element analysis model of the trackless bridge, and obtain the seismic response of the main beam based on the nonlinear finite element analysis model of the trackless bridge;

[0076] Beam-rail model building module: building a beam-rail nonlinear finite element model, wherein the beam-rail nonlinear finite element model obtains rail deformation based on the seismic response of the main beam obtained in step 1;

[0077] Calculation module: Based on the rail deformation calculation in step 2, the unevenness of the railway bridge track after the earthquake is obtained.

[0078] The circuits, electronic components and modules involved are all prior art and can be fully implemented by those skilled in the art. Needless to say, the content protected by the present invention does not involve improvements to software and methods.

[0079] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0080] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing track irregularity of railway beam bridges after earthquake, characterized in that: include: Step 1: Establish a nonlinear finite element analysis model of the trackless bridge, and obtain the seismic response of the main beam based on the nonlinear finite element analysis model of the trackless bridge; Step 2: Establishing a beam-rail nonlinear finite element model, wherein the beam-rail nonlinear finite element model obtains rail deformation based on the seismic response of the main beam obtained in step 1; Step 3: Based on the rail deformation calculation in step 2, the unevenness of the railway bridge track after the earthquake is obtained.

2. The method for analyzing track irregularity of a railway beam bridge after an earthquake according to claim 1 is characterized in that: The step 1 specifically includes: Step 1.1: Considering the nonlinearity of supports and piers, a nonlinear finite element analysis model of trackless bridge is established; Step 1.2: Input seismic waves into the nonlinear finite element analysis model of the trackless bridge and perform nonlinear time history analysis to obtain the seismic response of the main beam.

3. The method for analyzing track irregularity of a railway beam bridge after an earthquake according to claim 2 is characterized in that: The main beam seismic response includes relative peak displacement and residual displacement of adjacent main beam ends at each main beam expansion joint.

4. The method for analyzing track irregularity of a railway beam bridge after an earthquake according to claim 3 is characterized in that: The step 2 comprises: Step 2.1: Establish a beam-rail nonlinear finite element model based on the establishment rules; Step 2.2: The relative peak displacement and residual displacement obtained in step 1.2 are input as loads into the beam-rail nonlinear finite element model and applied to the main beam on the loading side. After the displacement loading is completed, the displacement of the main beam on the loading side is unloaded to the residual displacement size, and the displacement of the rail after unloading is recorded.

5. The method for analyzing track irregularity of a railway beam bridge after an earthquake according to claim 4 is characterized in that: In step 2.1, the establishment of rules includes: The beam-track nonlinear finite element model includes the main beam and track structure. The span needs to be considered to ensure the restraint force of the track on the main beam under earthquake action. The span of a single main beam is ≥5m. The main beam is set with a fixed side and a displacement loading side to simulate the seismic displacement behavior at the expansion joint of the main beam. The fixed side constrains the translation and rotation of the main beam, and the loading side main beam is not constrained; The main beam is modeled using beam elements, the track structure needs to consider the nonlinear mechanical characteristics of fasteners and rails, and other components are simulated using elastic elements.

6. The method for analyzing track irregularity of a railway beam bridge after an earthquake according to claim 1, characterized in that: The step 3 comprises: According to the rail deformation obtained in step 2, the track irregularity value is calculated using the chord measurement method, as shown in formula (1): V i ≈V i ′=H i -(H i-a +H i+a ) / 2 (1) Where: V i 、V i ′ is the track irregularity value; H i-a , H i , H i+a They are the distances that the starting point, midpoint and end point of the rail chord measure deviate from the original displacement.

7. A railway beam bridge post-earthquake track irregularity analysis system, used to implement a railway beam bridge post-earthquake track irregularity analysis method as described in claims 1-6, characterized in that: include: Trackless bridge model building module: build a nonlinear finite element analysis model of the trackless bridge, and obtain the seismic response of the main beam based on the nonlinear finite element analysis model of the trackless bridge; Beam-rail model building module: building a beam-rail nonlinear finite element model, wherein the beam-rail nonlinear finite element model obtains rail deformation based on the seismic response of the main beam obtained in step 1; Calculation module: Based on the rail deformation calculation in step 2, the post-earthquake railway bridge track irregularity value is obtained.

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