Railway station building post-earthquake function level evaluation method based on state tree

Abstract

The application discloses a kind of railway station building post-earthquake function level evaluation method based on state tree, specifically is: utilize multiple state trees to define the different function levels of railway station building, and determine the probability that railway station building is at different function levels after earthquake;First, determine the basic information and vulnerability information of the railway station building to be evaluated, and divide its post-earthquake function state into three kinds: all functions are intact, basic functions are intact, and functions are invalid;Then, according to the functional logic relationship of the internal components of the railway station building, two function state tree models are established to define the three function levels;Finally, time history analysis and Monte Carlo simulation are carried out to determine the probability that the post-earthquake railway station building is at each function level.The application has the characteristics of simple calculation process, open steps, strong structure pertinence, etc., can effectively evaluate or predict the function level of post-earthquake railway station building, provide more intuitive reference for investors, designers, decision makers, etc., and provide basis for the seismic design and post-earthquake function research of railway station building.

Description

Technical Field

[0001] This invention belongs to the field of seismic design of building structures, specifically involving a method for assessing the post-earthquake functional level of railway station buildings based on a state tree. Background Technology

[0002] Railway station buildings, as a crucial component of the railway network, undertake vital tasks such as train dispatching, passenger transport, and material distribution, making them a lifeline project for earthquake relief and disaster recovery. Based on their functional requirements, railway station buildings can be mainly divided into two parts: architecture and specialized equipment. The architecture primarily consists of entrance and exit halls, waiting halls, ticket offices, passenger service and ancillary rooms, baggage handling rooms, and commercial passenger service rooms. These buildings mainly include structural and non-structural components such as large-section beams and columns, ceilings with high floor acceleration, and infill walls with a high height-to-thickness ratio. The specialized equipment mainly consists of specialized equipment used to control the safe and efficient operation of trains, such as train control cabinets, interlocking cabinets, frequency shift cabinets, and relay combination cabinets. Significant damage to railway station buildings after a strong earthquake, leading to the disruption of railway transportation, will have a severe impact. Therefore, to ensure the transportation capacity of disaster areas after an earthquake, it is necessary to conduct pre-earthquake prediction and rapid post-earthquake assessment of the functions of railway station buildings.

[0003] The "state tree-based method" describes the basic components of a building and, combined with the success path method, establishes a state tree model to represent the functional logic relationships between different basic components. Then, based on the vulnerability of these components, the failure probability of the building is obtained, thereby assessing the post-earthquake functional level of the building. The state tree-based method can analyze the logical relationships between different basic components, explicitly consider the impact of each basic component on the system's function, and effectively reduce the computational load. It is suitable for establishing the functional logic relationships of complex systems and can be effectively used for the post-earthquake functional level assessment of complex functional building structures.

[0004] A search of existing patents and related technologies revealed that existing state tree-based evaluation methods mainly include: a state tree-based aircraft fault diagnosis and repair method (CN110386266B), which establishes a state tree model of aircraft functions to diagnose aircraft faults and provide repair methods; a state tree-based dialogue management method (CN109933654A), which stores the topic states during the dialogue process to build a state tree model, effectively improving question-and-answer efficiency and more efficiently understanding the customer's true intentions; and a state tree-based method for detecting motion events between indoor areas of people (CN107228669B), which establishes a state tree construction algorithm describing the dynamics of sensor event sequences and a state tree-based motion event detection method, effectively eliminating the adverse effects of indoor people's movement interference and instantaneous sensor failures on motion event detection.

[0005] The aforementioned state tree-based methods primarily predict the normal functions of the research objects, without focusing on the post-earthquake functional status of buildings or analyzing railway station buildings. The post-earthquake functional requirements of railway station buildings differ from other buildings; their structural components, non-structural components, and specialized equipment are complex, and the functional logic relationships between these components vary significantly. Currently, there is no method for assessing the post-earthquake functional level of railway station buildings. Therefore, a state tree-based method for assessing the post-earthquake functional level of railway station buildings is needed. Summary of the Invention

[0006] To address the current lack of an effective method for assessing the post-earthquake functional level of railway station buildings, this invention provides a state tree-based method for assessing the post-earthquake functional level of railway station buildings.

[0007] This invention discloses a post-earthquake functional level assessment method for railway station buildings based on state trees. It utilizes multiple state trees to define different functional levels of the railway station building and combines Monte Carlo simulation to determine the probability of the railway station building being at different functional levels after an earthquake. First, the basic information and vulnerability information of the railway station building to be assessed are determined, and its post-earthquake functional state is divided into three categories: fully functional, basically functional, and functionally failed. Then, based on the functional logic relationships of the internal components of the railway station building, two functional state tree models are established to define the three functional levels. Finally, time history analysis and Monte Carlo simulation are conducted to determine the probability of the railway station building being at each functional level after an earthquake. Specifically, the method includes the following steps:

[0008] Step 1: Select the railway station to be evaluated and collect its basic information, including the following aspects:

[0009] a) Site information, seismic grouping information, load distribution, and building material information of the railway station.

[0010] b) The structural form of the railway station building, the cross-sectional dimensions of beams, columns, and floor slabs, and the construction form of the connection nodes.

[0011] c) Perform load statistics and load combination calculations to establish a structural numerical analysis model.

[0012] Step 2: Identify the main structural components, non-structural components, and specialized equipment in railway station buildings that affect their function, and establish their performance models, including the following aspects:

[0013] a) Information on the quantity and cost of structural components, non-structural components, and specialized equipment on each floor of the railway station building.

[0014] b) Information on the vulnerability of structural components, non-structural components, and specialized equipment on each floor of the railway station building, and classify them into acceleration-sensitive and displacement-sensitive components.

[0015] Step 3: Classify the functional status of railway station buildings, including three states: fully functional, basically functional, and functionally inoperable. A fully functional railway station means that train operation is unaffected and all functions are available. A basically functional railway station means that trains passing through the station need to operate at limited speeds, and only one train can operate at a limited speed within the area between railway stations, resulting in low transportation efficiency. A functionally inoperable railway station means that the station cannot obtain train operation information, cannot dispatch trains, and cannot guarantee safe train operation.

[0016] Step 4: Establish two state tree models, M1 and M2, for the functions of railway station buildings to define the three functional levels of railway station buildings, including the following aspects:

[0017] a) Establish a state tree model M1 for the functions of the railway station building to define two states: all functions are intact and basic functions are intact. The state tree model M1 involves six sub-functions of the railway station building: power supply, interlocking, train control, section functions, centralized dispatching, and basic functions. The state of each sub-function is determined by the components and equipment involved in its function, and the functional logic relationship is expressed by the logical statements "and" and "or". "or" means that if any of the events under its gate fails, the event on the gate fails. "and" means that if all the events under its gate fail, the event on the gate fails.

[0018] b) Establish a state tree model M2 for the railway station building functions to define two states: the basic functions of the railway station building are intact and the functions of the railway station building are in failure. The state tree model M1 involves five sub-functions of the railway station building: power supply, interlocking, train control, centralized dispatching, and basic functions. The state of each sub-function is determined by the components and equipment involved in its function, and the functional logic relationship is expressed by the logical statements of "and" and "or". "or" means that if any of the events included under its gate fails, the event on the gate fails. "and" means that if all the events included under its gate fail, the event on the gate fails.

[0019] Step 5: Select ground motion records and perform time history analysis on the structure under the design earthquake and rare earthquake levels. Calculate the maximum inter-story drift angle θ and peak floor acceleration FPA of the railway station structure. Determine the mean μ and standard deviation σ of the maximum inter-story drift angle and peak floor acceleration for each floor of the railway station.

[0020] Step 6: Determine the damage state of each component in the state tree model and the top-level functional status of the functional state tree, including the following aspects:

[0021] a) Generate a random number between 0 and 1 for each basic component. Compare the random number of each component with its functional failure probability threshold. If the random number is less than the functional failure probability threshold, the component is considered to be working normally; if the random number is greater than the functional failure probability threshold, the component is considered to be failed.

[0022] b) Based on the logical relationships between the basic components and the calculation rules of the state tree model, analyze the top-level functional states of the state tree models M1 and M2 of each subsystem under the earthquake.

[0023] Step 7: Based on the top-level functional information of the state tree model, determine the functional level of the railway station building, including the following aspects:

[0024] a) When the top-level function of the state tree model M1 is effective, all functions of the railway station building are intact.

[0025] b) When the top-level function of state tree model M1 fails, the top-level function of state tree model M2 is effective, and the railway station building has basic functions.

[0026] c) When the top-level function of the state tree model M2 fails, the railway station building function also fails.

[0027] Step 8: Conduct no fewer than 1,000 Monte Carlo simulations to determine the damage status of each component in the railway station building after each simulation.

[0028] Step 9: Calculate the number of times the railway station building is at each functional level after the Monte Carlo simulation, and determine the probability of the railway station building being at each functional level after the earthquake, as shown in formula (1).

[0029]

[0030] In the formula: P i The probabilities of each functional level of the railway station building, where i takes values ​​of 1, 2, and 3, representing the three states of the railway station building: all functions intact, basic functions intact, and functions failed, respectively; N is the total number of Monte Carlo simulations; N i,success Let represent the number of times the function is implemented in the i-th state of the railway station building.

[0031] The beneficial technical effects of this invention compared to the prior art are as follows:

[0032] This invention can be used for the assessment and prediction of the post-earthquake functional level of railway station buildings. By clarifying the functional logic relationships of structural components, non-structural components, and specialized equipment affecting the function of railway station buildings, two functional state tree models of railway station buildings are established to define three functional levels: all functions intact, basic functions intact, and functional failure. Simultaneously, at least 1000 simulations are conducted using the Monte Carlo method, considering the uncertainty of seismic motion, and the probability of the railway station building being at each functional level after an earthquake is given. The proposed state tree-based method for assessing the post-earthquake functional level of railway station buildings features a simple calculation process, open calculation steps, and strong structural specificity. It can effectively assess or predict the post-earthquake functional level of railway station buildings, providing a more intuitive reference for investors, users, and decision-makers, and providing a basis for the seismic design and post-earthquake functional research of railway station buildings. Attached Figure Description

[0033] Figure 1 This is a flowchart of the post-earthquake functional level assessment method for railway station buildings based on state tree according to the present invention.

[0034] Figure 2 The example shows a railway station building to be evaluated. Figure 2 In the middle: 2-1, first-floor waiting room; 2-2, second-floor waiting room; 2-3, train; 2-4, overpass.

[0035] Figure 3 This is the numerical model of the railway station building to be evaluated in the example.

[0036] Figure 4 The image shows the fragility curves of a typical component in the embodiment.

[0037] Figure 5 The railway station building functional state tree model M1 is shown in the embodiment.

[0038] Figure 6 The railway station building functional state tree model M2 is shown in the embodiment. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0040] A flowchart of a post-earthquake functional level assessment method for railway station buildings based on a state tree, as described in this invention, is as follows: Figure 1 As shown, specifically:

[0041] Step 1: Select the railway station building to be evaluated. This railway station building consists of 5 floors: the first floor, the first mezzanine, the second floor, the second mezzanine, and the roof. Figure 2 As shown; clearly define the basic information of the railway station building, including the following aspects:

[0042] a) The railway station building is classified as a standard seismic fortification type, with a structural safety level of Level II, a seismic fortification intensity of 8 degrees (0.3g), a site category of Class II, and a structural design service life of 50 years. The main load values ​​of the railway station building are shown in Table 1, and the main materials of the railway station building are shown in Table 2.

[0043] Table 1 Main Load Values

[0044]

[0045] Table 2 Main Materials

[0046]

[0047] b) The railway station building has a structural form that is a combination of a concrete frame structure and a steel square pyramidal space frame. The roof type is a square pyramidal space frame. The cross-sectional dimensions of the beams, columns and floor slabs are shown in Table 3.

[0048] Table 3 Structural Layout Parameters of Railway Station Buildings

[0049]

[0050] c) Perform load statistics and load combination calculations on the railway station building structure, and establish a numerical analysis model of the railway station building structure using the finite element software Midas / Gen, such as... Figure 3 As shown.

[0051] Step 2: Identify the main structural components, non-structural components, and specialized equipment in railway station buildings that affect their function, determine their vulnerability curves, and establish their performance models, including the following aspects:

[0052] a) Count the number and type of structural components, non-structural components and specialized equipment in each floor of the railway station building, as shown in Table 4.

[0053] Table 4 Vulnerable Components of Railway Station Buildings

[0054]

[0055]

[0056] b) Collect vulnerability information on structural components, non-structural components, and specialized equipment on each floor of the railway station building, classifying them into acceleration-sensitive and displacement-sensitive components. Damage to structural components is divided into four levels, while damage to non-structural components and equipment is divided into three levels. Examples of vulnerability curves for typical components are provided. Figure 4 As shown.

[0057] Step 3: Based on the operation mode of the railway station building, classify the functional level status of the railway station building, including three states: all functions are intact, basic functions are intact, and functions are ineffective.

[0058] A fully functional railway station means that train operation at the station is unaffected after an earthquake, possessing all necessary functions. This requires the six sub-functions of the station: power supply, interlocking, train control, track maintenance, centralized dispatching, and basic functions. A basically functional railway station means that trains need to operate at limited speeds, and only one train can operate within the track between stations, resulting in lower transport efficiency. This requires the power supply, interlocking, train control, centralized dispatching, and basic functions to be intact. A functionally failed railway station means that the station cannot obtain train operation information, cannot dispatch trains, and cannot guarantee safe train operation. The railway station is considered to be at that functional level when any one of the following functions fails: power supply, interlocking, train control, or basic functions.

[0059] Step 4: Based on the different functional levels of the railway station building and the functional logic relationships of each component, establish a state tree model based on the functions of the railway station building.

[0060] a) Establish a state tree model M1 for the functions of a railway station building, involving power supply, interlocking, train control, section functions, centralized dispatching, and basic functions. This model is used to define two states: complete functionality and complete basic functionality of the railway station building. Figure 5 As shown.

[0061] b) Establish a state tree model M2 for the functions of the railway station building, involving power supply, interlocking, train control, centralized dispatching, and basic functions. This model is used to define two states: the basic functions of the railway station building are intact, and the functions of the railway station building are ineffective. Figure 6 As shown.

[0062] Step 5: Select ground motion records and perform time history analysis on the railway station structure under the design earthquake and rare earthquake levels to determine the mean and standard deviation of the maximum inter-story drift angle and floor acceleration of the railway station, as shown in Tables 5 and 6.

[0063] Table 5 Seismic Response of Railway Station Buildings under Fortified Earthquake Action (Table 5)

[0064]

[0065]

[0066] Table 6 Seismic Response of Railway Station Buildings under Rare Earthquakes

[0067]

[0068] Step 6: Determine the damage status of each component in the railway station building, and use a state tree model to determine the post-earthquake functional status of the railway station building.

[0069] a) Based on the mean μ and standard deviation σ of the maximum inter-story displacement and peak floor acceleration of each floor of the railway station building, the damage status of each component is determined based on the vulnerability index of component damage. In one Monte Carlo simulation, a random number between 0 and 1 is first generated. If the generated random number is less than or equal to the failure probability determined by the vulnerability curve of the component, the component is considered to have failed. If the generated random number is greater than the failure probability determined by the vulnerability curve of the component, the component is considered to have succeeded and is operating normally. The component damage status results of a certain Monte Carlo simulation are given here, as shown in Table 7.

[0070] Table 7. Damage status of components after a Monte Carlo simulation.

[0071]

[0072]

[0073] b) Based on the damage state of each component and the functional logic relationship between each component, calculate the branch paths of the state tree model under the design earthquake and the rare earthquake. In this simulation, under the design earthquake, the top-level function of the functional state tree model M1 is effective, and the top-level function of the functional state tree model M2 is effective. Under the rare earthquake, the top-level function of the functional state tree model M1 is effective, and the top-level function of the functional state tree model M2 fails.

[0074] Step 7: Determine the functional level of the railway station building by combining the top-level functional information of the state tree model.

[0075] In this simulation, under the design earthquake, when the top-level function of the functional state tree model M1 is effective, the railway station building's functional level is that all functions are intact; under the rare earthquake, the top-level function of the functional state tree model M1 fails, the top-level function of the functional state tree model M2 fails, and the railway station building's functional level is that all functions are lost.

[0076] Step 8: Using the Monte Carlo method to consider the uncertainty of ground motion, determine the damage status of each component of the railway station building after no less than 1000 simulations.

[0077] a) Based on the mean μ and standard deviation σ of the maximum inter-story displacement and peak floor acceleration of each floor of the railway station building under 11 seismic ground motions, 1000 Monte Carlo simulations were conducted to effectively consider the uncertainty of seismic action.

[0078] b) Based on the vulnerability index of component damage, determine the damage status of each component after 1000 Monte Carlo simulations.

[0079] Step 9: Calculate the functional level of the railway station after each Monte Carlo simulation. Calculate the probability of each functional level of the railway station according to formula (1), as shown in Table 8.

[0080] Table 8. Probability of Different Functional Levels of Railway Station Buildings

[0081]

[0082] Formula (1) is:

[0083]

[0084] In the formula: P i The probabilities of each functional level of the railway station building, where i takes values ​​of 1, 2, and 3, representing the three states of the railway station building: all functions intact, basic functions intact, and functions failed, respectively; N is the total number of Monte Carlo simulations; N i,success Let represent the number of times the function is implemented in the i-th state of the railway station building.

Claims

1. A method for assessing the post-earthquake functional level of railway station buildings based on a state tree, characterized in that, Multiple state trees are used to define different functional levels of railway station buildings, and Monte Carlo simulation is combined to determine the probability of railway station buildings being at different functional levels after an earthquake. First, the basic information and vulnerability information of the railway station buildings to be evaluated are determined, and their post-earthquake functional status is divided into three types: all functions intact, basic functions intact, and functions failed. Then, based on the functional logic relationship of the internal components of the railway station building, two functional state tree models were established to define three functional levels; finally, time history analysis and Monte Carlo simulation were carried out to determine the probability of the railway station building being at each functional level after the earthquake. Specifically, the following steps are included: Step 1: Select the railway station to be evaluated and collect its basic information, including the following aspects: a) Site information, seismic grouping information, load distribution, and building material information of the railway station building; b) The structural form of the railway station building, the cross-sectional dimensions of beams, columns, and floor slabs, and the construction form of the connection nodes; c) Perform load statistics and load combination calculations to establish a structural numerical analysis model; Step 2: Identify the main structural components, non-structural components, and specialized equipment in railway station buildings that affect their function, and establish their performance models, including the following aspects: a) Information on the quantity and cost of structural components, non-structural components, and specialized equipment on each floor of the railway station building; b) Information on the vulnerability of structural components, non-structural components, and specialized equipment on each floor of the railway station building, and classify them into acceleration-sensitive and displacement-sensitive components; Step 3: Classify the functional status of railway station buildings into three levels: fully functional, basically functional, and functionally inoperable. A fully functional railway station means that train operation is unaffected and all functions are available. A basically functional railway station means that trains passing through the station need to operate at limited speeds, and only one train can operate at a limited speed within the area between railway stations, resulting in low transportation efficiency. A functionally inoperable railway station means that the station cannot obtain train operation information, cannot dispatch trains, and cannot guarantee safe train operation. Step 4: Establish two state tree models, M1 and M2, for the functions of railway station buildings to define the three functional levels of railway station buildings, including the following aspects: a) Establish a state tree model M1 for the functions of the railway station building to define two states: all functions are intact and basic functions are intact. The state tree model M1 involves six sub-functions of the railway station building: power supply, interlocking, train control, section functions, centralized dispatching, and basic functions. The state of each sub-function is determined by the components and equipment involved in its function, and the functional logic relationship is expressed by "and" and "or" logical statements. "or" means that if any of the events under its gate fails, the event on the gate fails. "and" means that if all the events under its gate fail, the event on the gate fails. b) Establish a state tree model M2 for the railway station building functions to define two states: the basic functions of the railway station building are intact and the functions of the railway station building are in failure. The state tree model M1 involves five sub-functions of the railway station building: power supply, interlocking, train control, centralized dispatching, and basic functions. The state of each sub-function is determined by the components and equipment involved in its function, and the functional logic relationship is expressed by "and" and "or" logical statements. "or" means that if any of the events under its gate fails, the event on the gate fails. "and" means that if all the events under its gate fail, the event on the gate fails. Step 5: Select ground motion records and perform time history analysis on the structure under the design earthquake and rare earthquake levels. Calculate the maximum inter-story drift angle θ and peak floor acceleration FPA of the railway station building structure. Determine the mean μ and standard deviation σ of the maximum inter-story drift angle and peak floor acceleration for each floor of the railway station building. Step 6: Determine the damage state of each component in the state tree model and the top-level functional status of the functional state tree, including the following aspects: a) Generate a random number between 0 and 1 for each basic component. Compare the random number of each component with its functional failure probability threshold. If the random number is less than the functional failure probability threshold, the component is considered to be working normally; if the random number is greater than the functional failure probability threshold, the component is considered to be failed. b) Based on the logical relationships between the basic components and the calculation rules of the state tree model, analyze the top-level functional states of the state tree models M1 and M2 of each subsystem under this earthquake action. Step 7: Based on the top-level functional information of the state tree model, determine the functional level of the railway station building, including the following aspects: a) When the top-level function of the state tree model M1 is effective, all functions of the railway station building are intact; b) When the top-level function of state tree model M1 fails, the top-level function of state tree model M2 is effective, and the railway station building has basic functions. c) When the top-level function of the state tree model M2 fails, the railway station building function also fails. Step 8: Conduct no less than 1000 Monte Carlo simulations to determine the damage status of each component in the railway station building after each simulation; Step 9: Calculate the number of times the railway station building is at each functional level after the Monte Carlo simulation, and determine the probability of the railway station building being at each functional level after the earthquake, as shown in formula (1); In the formula: P i The probabilities of each functional level of the railway station building, where i takes values ​​of 1, 2, and 3, representing the three states of the railway station building: all functions intact, basic functions intact, and functions failed, respectively; N is the total number of Monte Carlo simulations; N i,success Let represent the number of times the function is implemented in the i-th state of the railway station building.

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