Method and system for monitoring seismic performance of building structures

Abstract

The present invention relates to the field of building structure safety detection, and discloses a method and system for monitoring the seismic performance of building structures. The method includes: collecting multi-source response data such as acceleration, displacement, strain and tilt angle; obtaining the standard response of the structure based on wavelet denoising and normalization processing; extracting the dynamic characteristic parameters of the structure using a multi-order modal recognition algorithm; conducting structural damage assessment based on modal change indicators, and calculating the residual bearing capacity of the structure by integrating yield strength, load index and displacement margin; and finally outputting a seismic grade warning signal. The system includes a structural response acquisition module, a modal recognition and damage assessment module, and a residual bearing capacity calculation and warning module. The invention can realize real-time quantitative analysis of the performance of a structure under earthquake or load, with high assessment accuracy and strong applicability, and has broad engineering promotion value.

Description

Technical Field

[0001] The present invention relates to the field of building structure safety detection, and in particular to a method and system for monitoring the seismic performance of a building structure. Background Art

[0002] Traditional monitoring methods lack the ability to identify dynamic responses: Existing building structure safety monitoring mostly uses single sensors such as strain gauges and displacement gauges, which are mainly used to monitor static loads or long-term settlement trends. It is difficult to effectively capture the high-frequency and transient responses generated by seismic excitation, resulting in the inability to fully restore the dynamic evolution process of structural damage, which seriously restricts the accuracy of seismic performance assessment.

[0003] Low accuracy in modal parameter identification and difficulty in quantifying damage: Although some current methods have introduced modal analysis ideas, they mostly rely on traditional frequency domain methods. Under conditions of noise interference or sparse measurement points, the accuracy of modal frequency, damping ratio, and vibration mode identification is low, and sensitive detection of early micro-damage cannot be achieved. It is easy to miss or delay the judgment, which is especially prominent in large-span structures or complex connection nodes.

[0004] Lack of a quantitative calculation mechanism for residual seismic capacity: Existing structural assessment methods mostly use damage as the judgment standard, ignoring the nonlinear evolution law of the structure's bearing capacity reduction after earthquake loads. There is a lack of a comprehensive assessment model that integrates the structure's yield strength, deformation capacity and energy dissipation capacity, and it is unable to provide quantitative basis for whether the structure can continue to serve or needs to be evacuated immediately. Summary of the Invention

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solution: a method for monitoring the seismic performance of a building structure, comprising the following steps:

[0006] S1. Structural response data acquisition: Real-time acquisition of the response data of the building structure under earthquake action through multiple types of sensors. The response data includes acceleration data. , displacement data , strain data and tilt angle data ;

[0007] S2. Dynamic feature extraction and modal identification: Based on the collected structural response data, the improved modal parameter identification algorithm is used to extract the main dynamic characteristic parameters of the building structure under the current working conditions. The dynamic characteristic parameters include the natural frequency , damping ratio , main mode shape ;

[0008] S3. Calculation and evaluation of earthquake damage index, based on the extracted modal eigenvectors Compared with historical benchmark modal parameters Compare and calculate the modal change ratio matrix , and then according to the modal change ratio matrix Compared with the standard modal change threshold Calculate injury index and output health status indicators through fuzzy logic reasoning model , the specific steps are as follows:

[0009] S3 (1), according to the extracted modal feature vector Compared with historical benchmark modal parameters Calculate and get the modal change ratio matrix :

[0010] ;

[0011] Among them, the historical benchmark modal parameters The stable modal center value is obtained by averaging the clustering algorithm to ensure robustness. The calculation formula is:

[0012] ;

[0013] in, For the modal eigenvectors of group data;

[0014] S3 (2), the modal change ratio matrix Compared with the standard modal change threshold Compare and construct the damage index Indicates the degree of damage to the structure:

[0015] ;

[0016] in, is the damage index, For the The modal change ratio matrix of the group data, for

[0017] No. The standard modal change threshold of group data, , is the historical benchmark modal parameter The mean of is the historical benchmark modal parameter The standard deviation of , dynamically adjustable according to the actual allowable error;

[0018] S3 (3), combined with health status indicators and injury index The fuzzy logic reasoning system is used to determine the current state of the structure:

[0019] ;

[0020] in, is the fuzzy logic reasoning function, when When it is <0.98, an early warning is triggered, and it is determined that the seismic performance of the structure under the current working conditions is poor.

[0021] S4. Calculation and early warning of the remaining structural load-bearing capacity, using a multi-parameter fusion evolution model combined with current health status indicators , maximum response value and design strength of structural components , calculate the residual seismic bearing capacity of the building structure , and generate graded warning information based on the calculation results .

[0022] Preferably, the step S1 specifically includes:

[0023] S1 (1) Three-axis acceleration sensors, fiber Bragg grating displacement meters, MEMS tilt sensors and resistance strain gauges are respectively arranged at key nodes of the structure to sample the response data generated by the building structure during earthquake excitation in real time. The response data includes acceleration data , displacement data , strain data and tilt angle data ;

[0024] S1 (2), the acquisition frequency range is set to [100, 500] Hz, to meet the need to capture low-order modes of the structure;

[0025] S1 (3) The collected raw data is processed and converted into a standard response data set using the following algorithm :

[0026] ;

[0027] in, For the collected data set , For the The mean of the group data, For the The standard deviation of the group data, is the wavelet denoising function;

[0028] S1 (4), the processed response data is timestamped As the index, form a multidimensional data matrix:

[0029] ;

[0030] Preferably, the step S2 specifically includes:

[0031] S2 (1), based on the data matrix obtained in step S1 , the improved modal parameter identification algorithm is used to extract the main modal features:

[0032] ;

[0033] ;

[0034] ;

[0035] in, is the natural frequency extraction function, is the damping identification function, is the mode shape identification function, is the natural frequency of the building structure, is the building structure damping ratio, is the main mode shape of the building structure;

[0036] S2 (2) The extracted modal characteristic parameters are combined into a modal characteristic vector :

[0037] ;

[0038] in, is the number of modal characteristic parameters.

[0039] Preferably, the step S4 specifically includes:

[0040] S4 (1) Comprehensively consider the design strength of structural components based on the current damage status , maximum response value , current health status indicators , the residual seismic bearing capacity of the building structure :

[0041] ;

[0042] in, is the residual seismic bearing capacity of the building structure, It is the allowable value of the critical response of the structure, which is a fixed threshold and can be queried through the structural material description. 、 The adjustment coefficient preset by the system satisfies =0.85, =0.6;

[0043] S4 (2), combined Set safety load threshold with the structure Perform comparisons to determine the current structural status and trigger multi-level warning signals:

[0044] ;

[0045] in, It is a graded warning information, corresponding to normal, minor, moderate and severe warnings. Setting thresholds for building structural standards.

[0046] The present invention also provides a building structure seismic performance monitoring system, comprising the following modules:

[0047] Structural response data acquisition module, used to collect multi-dimensional response data of building structures in real time under earthquake excitation;

[0048] The modal identification and damage assessment module is used to extract modal features and determine damage status based on the collected response data, calculate the damage index based on the modal change ratio matrix and the standard modal change threshold, and output the health status index through the fuzzy logic reasoning model. ;

[0049] The residual bearing capacity calculation and early warning module is used to calculate the residual seismic bearing capacity and generate graded early warning information based on health status indicators, design strength and maximum corresponding values.

[0050] The structural response data acquisition module includes:

[0051] The sensor deployment unit is used to deploy triaxial acceleration sensors, fiber Bragg grating displacement meters, resistance strain gauges and MEMS tilt sensors at key nodes of the building structure to obtain acceleration , displacement ,strain With tilt angle data;

[0052] Data preprocessing unit, used to perform wavelet denoising on the collected data and construct a unified response data set after standardization , and generate a timestamp-based The multidimensional response matrix ;

[0053] Sampling control unit, setting sampling frequency [100, 500] Hz, which meets the frequency domain requirements for extracting low-order modal features of the structure.

[0054] The modal identification and damage assessment module includes:

[0055] Modal parameter identification unit, based on standard response data set , using an improved modal identification algorithm to extract the natural frequency of the building structure , damping ratio , main mode shape , forming the modal eigenvector ;

[0056] The damage index calculation unit converts the modal eigenvector Compared with historical benchmark modal parameters Compare and calculate the modal change ratio and by comparing with the standard threshold Compare and get the damage index ;

[0057] Health status assessment unit, using fuzzy logic reasoning function , combined with the injury index , modal change ratio and the main mode shape , output health status indicators , and judge whether to enter the warning state accordingly.

[0058] The remaining bearing capacity calculation and early warning module includes:

[0059] The residual bearing capacity calculation unit comprehensively considers the design strength of structural components based on the current damage state , maximum response value , current health status indicators , the residual seismic bearing capacity of the building structure :

[0060] Safety threshold judgment unit, residual seismic bearing capacity of building structures and setting safety thresholds Compare and judge the current load safety status;

[0061] A graded warning information generation unit generates a warning level based on the comparison results , its value is divided according to the following conditions:

[0062] ;

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] Achieve full-cycle high-precision monitoring of structural responses and dynamic damage identification: By fusing multi-source data (acceleration, displacement, strain), it is possible to continuously identify structural vibration modes, key node responses, and damage evolution paths throughout the entire earthquake process. This overcomes the problem of traditional monitoring methods' weak ability to capture transient earthquake responses, and enables dynamic assessment of structural status from non-destructive to slightly damaged to severely damaged.

[0065] Constructing a quantitative assessment model for seismic performance based on damage indicators: This invention introduces comprehensive damage indicators and combines them with a structural residual bearing capacity calculation model to quantitatively deduce the seismic residual capacity of the structure in its current state, effectively supporting subsequent engineering decisions such as whether to continue service or whether to reinforce it, thus solving the problem of the lack of quantitative seismic criteria in existing technologies.

[0066] Modular system design, strong adaptability and wide application range: The proposed system adopts a distributed structure that combines a sensor integration module, a data acquisition and processing module and an intelligent judgment module. It can be widely used in seismic monitoring of different types of structures such as high-rise buildings, bridges, tunnels, etc. It supports remote deployment and dynamic updating of algorithm models, and has good scalability and engineering feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 A schematic flow chart of the method steps provided in this application;

[0068] Figure 2 Schematic diagram of the system modules provided for this application. DETAILED DESCRIPTION

[0069] In order to enable those skilled in the art to better understand the solutions of the present invention, 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0070] refer to Figure 1 , an embodiment of the present invention provides a method for monitoring the seismic performance of a building structure, comprising the following steps:

[0071] Step 1: Structural response data collection: Use multiple types of sensors to collect real-time response data of the building structure under earthquake action. The response data includes acceleration data. , displacement data , strain data and tilt angle data .

[0072] In step 1, three-axis acceleration sensors, fiber Bragg grating displacement meters, MEMS tilt sensors and resistance strain gauges are deployed at multiple key nodes of the building structure to obtain real-time structural response data under earthquake excitation, including acceleration data. , displacement data , strain data and tilt angle data The data acquisition frequency of all sensors was then uniformly set to 200 Hz to ensure that the low-order modal response of the structure under seismic loads was captured. Input wavelet denoising function respectively , using the db4 wavelet basis to perform three-level decomposition and reconstruction to obtain denoised data. Then, each type of data is normalized:

[0073] ;

[0074] in, and are the mean and standard deviation of each type of data in the observation period.

[0075] The processed data is stored at intervals of 0.005s to form a standard response data matrix , as shown below:

[0076] ;

[0077] Step 2: Dynamic feature extraction and modal identification: Based on the collected structural response data, the improved modal parameter identification algorithm is used to extract the main dynamic characteristic parameters of the building structure under the current working conditions. The dynamic characteristic parameters include the natural frequency , damping ratio , main mode shape .

[0078] In step 2, first Input the improved modal parameter identification algorithm to extract the main modal characteristics of the structure:

[0079] , the first three natural frequencies extracted are 2.1Hz, 5.4Hz and 8.3Hz respectively;

[0080] , the corresponding damping ratios are 2.3%, 2.7%, and 3.0% respectively;

[0081] , the main mode shape vectors of each order are normalized and used for subsequent comparison.

[0082] The modal features are then combined into a modal vector:

[0083] ;

[0084] in, is the number of modal characteristic parameters.

[0085] Step 3: Calculation and evaluation of earthquake damage index, based on the extracted modal eigenvectors Compared with historical benchmark modal parameters Compare and calculate the modal change ratio matrix , and then according to the modal change ratio matrix Compared with the standard modal change threshold Calculate injury index and output health status indicators through fuzzy logic reasoning model .

[0086] In step 3, the modal center value of the structure under the historical stable working condition in the database is first called as the benchmark modal parameter , use the following formula to calculate the modal change ratio matrix :

[0087] ;

[0088] Among them, the historical benchmark modal parameters The stable modal center value is obtained by averaging the clustering algorithm to ensure robustness. The calculation formula is:

[0089] ;

[0090] in, For the modal eigenvectors of group data;

[0091] Then, according to the set standard threshold (k=2.5) to perform difference analysis and calculate the damage index:

[0092] ;

[0093] Get the current damage index =2.13, which has reached the preset sensitive detection threshold.

[0094] Finally, combined with the fuzzy logic reasoning system, input 、 、 to In the inference model, the module formula is: , output current health indicators =0.91, indicating that the structure is in an alert state and the system automatically triggers the early warning mechanism.

[0095] Step 4: Calculate and warn the remaining load-bearing capacity of the structure using a multi-parameter fusion evolution model combined with current health status indicators. , maximum response value and design strength of structural components , calculate the residual seismic bearing capacity of the building structure , and generate graded warning information based on the calculation results .

[0096] In step 4, the current maximum response value is integrated =0.76, material description of the critical response allowable value of the structure given =1.0, and the design strength of structural members =300MPa, calculate the residual seismic bearing capacity:

[0097] ;

[0098] in =0.85, =0.6, substitute and calculate =132.5 MPa.

[0099] Finally, the remaining seismic bearing capacity and the set safety load threshold =120 MPa, and combined with:

[0100] ;

[0101] It is judged to be a minor warning level, corresponding to the warning information level =1, automatically issues a yellow signal and generates a structural monitoring report.

[0102] refer to Figure 2 , an embodiment of the present invention provides a building structure seismic performance monitoring system, including the following modules:

[0103] The structural response data acquisition module is used to collect multi-dimensional response data of building structures in real time under earthquake excitation.

[0104] In the structural response data acquisition module, firstly, triaxial acceleration sensors, fiber Bragg grating displacement meters, resistance strain gauges and MEMS tilt sensors are arranged at key locations such as the beam-column intersection nodes, the top and bottom of the shear wall, the center and four corners of the floor, etc. The sensor numbers are bound to the corresponding relationship of the building BIM model to ensure accurate spatial positioning. At the same time, the sensors obtain acceleration in real time. , displacement ,strain With tilt angle Data, while the acquisition frequency range is set to [100, 500] Hz, to meet the need to capture the low-order modes of the structure. Then the data preprocessing unit puts the original data into wavelet denoising to eliminate environmental noise. The denoised data is normalized according to each dimension and uniformly converted into standard response data: The final processed response data is timestamped As the index, form a multidimensional data matrix:

[0105] ;

[0106] The modal identification and damage assessment module is used to extract modal features and determine damage status based on the collected response data, and generate health status indicators and damage indexes for building structures.

[0107] In the modal identification and damage assessment module, the modal parameter identification unit first receives the standard response data set processed by the structural response data acquisition module. , through the embedded improved modal identification algorithm, extract the key modal parameters of the current building structure, including the natural frequency , damping ratio and the main mode shape vector , and the above parameters are combined to form the modal eigenvector Then, the damage index calculation unit calculates the current modal eigenvector Compared with the historical benchmark modal parameters built into the system Compare component by component and calculate the modal change ratio and compare it with the set standard threshold Comparison is made to evaluate the magnitude of structural response changes and calculate the damage index accordingly On this basis, the health status assessment unit calls the fuzzy logic reasoning function , comprehensive input damage index , modal change ratio and the main mode shape , through the preset membership function and rule base, fuzzy reasoning is performed to output the health status index that represents the overall health status of the structure , and automatically determine whether the building structure is currently in a warning state based on the index value, providing a basis for subsequent bearing capacity calculation and warning classification.

[0108] The residual bearing capacity calculation and early warning module is used to calculate the residual seismic bearing capacity and generate graded early warning information based on health status indicators, design strength and maximum corresponding values.

[0109] First, the residual bearing capacity estimation unit receives the current damage state parameters output by the front-end module and comprehensively calls the component design strength parameters in the structural design database. , and the maximum response value recorded during the actual monitoring process , combined with the health status indicators obtained from the current assessment , through the set calculation model, the residual seismic bearing capacity of the building structure in the current state Then, the safety threshold determination unit calculates the remaining carrying capacity. Pre-set security thresholds Compare and analyze whether the building structure is in a safe state or has potential risks. Significantly higher than When the system determines that the structural safety margin is sufficient; if it is close to or below the threshold, it is considered that there are safety hazards of different levels. Based on the above comparison results, the graded warning information generation unit divides the current structural status into grades according to the built-in judgment rules and generates a warning level. The warning level is automatically divided into four levels according to the ratio of the structure's remaining bearing capacity to the safety threshold, from safe (level 0) to serious warning (level 3). Finally, the warning information of the corresponding level is transmitted to the monitoring terminal through the interface for management personnel to dispatch or implement emergency response measures in real time.

[0110] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions therein may be combined with each other.

[0111] Obviously, the embodiments described above are only some embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned specific embodiments, or to make equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the present invention specification and drawings, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A method for monitoring the seismic performance of a building structure, characterized in that: The following steps are involved: S1. Structural response data acquisition: Real-time acquisition of the response data of the building structure under earthquake action through multiple types of sensors. The response data includes acceleration data. , displacement data , strain data and tilt angle data ; S2. Dynamic feature extraction and modal identification: Based on the collected structural response data, the improved modal parameter identification algorithm is used to extract the main dynamic characteristic parameters of the building structure under the current working conditions. The dynamic characteristic parameters include the natural frequency , damping ratio , main mode shape , and form the modal eigenvector ; S3. Calculation and evaluation of earthquake damage index, based on the extracted modal eigenvectors Compared with historical benchmark modal parameters Perform calculations to calculate the modal change ratio matrix , and then according to the modal change ratio matrix Compared with the standard modal change threshold Calculate injury index and output health status indicators through fuzzy logic reasoning model , the specific steps are as follows: S3 (1), according to the extracted modal feature vector Compared with historical benchmark modal parameters Calculate and get the modal change ratio matrix : ； Among them, the historical benchmark modal parameters The stable modal center value is obtained by averaging the clustering algorithm to ensure robustness. The calculation formula is: ； in, For the modal eigenvectors of group data; S3 (2), the modal change ratio matrix Compared with the standard modal change threshold Compare and construct the damage index Indicates the degree of damage to the structure: ； in, is the damage index, For the The modal change ratio matrix of the group data, for No. The standard modal change threshold of group data, , is the historical benchmark modal parameter The mean of is the historical benchmark modal parameter The standard deviation of , dynamically adjustable according to the actual allowable error; S3 (3), combined with health status indicators and injury index The fuzzy logic reasoning system is used to determine the current state of the structure: ； in, is the fuzzy logic reasoning function, when When the value is less than 0.98, an early warning is triggered, and it is determined that the seismic performance of the structure is poor under the current working conditions; S4, calculation and early warning of the residual bearing capacity of the structure, using a multi-parameter fusion evolution model combined with the current health status indicators , maximum response value and design strength of structural components , calculate the residual seismic bearing capacity of the building structure , and generate graded warning information based on the calculation results .

2. A method for monitoring the seismic performance of a building structure according to claim 1, characterized in that: The step S1 specifically includes: S1 (1) Three-axis acceleration sensors, fiber Bragg grating displacement meters, MEMS tilt sensors and resistance strain gauges are respectively arranged at key nodes of the structure to sample the response data generated by the building structure during earthquake excitation in real time. The response data includes acceleration data , displacement data , strain data and tilt angle data ; S1 (2), the acquisition frequency range is set to [100, 500] Hz, to meet the need to capture low-order modes of the structure; S1 (3) The collected raw data is processed and converted into a standard response data set using the following algorithm : ； in, For the collected data set , For the The mean of the group data, For the The standard deviation of the group data, is the wavelet denoising function; S1 (4), the processed response data is timestamped As the index, form a multidimensional data matrix: 。 3. The method according to claim 1, characterized in that The step S2 specifically includes: S2 (1), based on the data matrix obtained in step S1 , the improved modal parameter identification algorithm is used to extract the main modal features: ； ； ； in, is the natural frequency extraction function, is the damping identification function, is the mode shape identification function, is the natural frequency of the building structure, is the building structure damping ratio, is the main mode shape of the building structure; S2 (2) The extracted modal characteristic parameters are combined into a modal characteristic vector : ； in, is the number of modal characteristic parameters.

4. A method for monitoring the seismic performance of a building structure according to claim 1, characterized in that: The step S4 specifically includes: S4 (1) Comprehensively consider the design strength of structural components based on the current damage status , maximum response value , current health status indicators , the residual seismic bearing capacity of the building structure : ； in, is the residual seismic bearing capacity of the building structure, It is the allowable value of the critical response of the structure, which is a fixed threshold and can be queried through the structural material description. 、 The adjustment coefficient preset by the system satisfies =0.85, =0.6; S4 (2), combined Set safety load threshold with the structure Perform comparisons to determine the current structural status and trigger multi-level warning signals: ； in, It is a graded warning information, corresponding to normal, minor, moderate and severe warnings. Setting thresholds for building structural standards.

5. A building structure seismic performance monitoring system, characterized in that: Includes the following modules: Structural response data acquisition module, used to collect multi-dimensional response data of building structures in real time under earthquake excitation; The modal identification and damage assessment module is used to extract modal features and determine damage status based on the collected response data, calculate the damage index based on the modal change ratio matrix and the standard modal change threshold, and output the health status index through the fuzzy logic reasoning model. , the specific calculation is as follows: Through the natural frequency , damping ratio , main mode shape , forming the modal eigenvector ; According to the extracted modal eigenvector Compared with historical benchmark modal parameters Calculate and get the modal change ratio matrix : ； Among them, the historical benchmark modal parameters The stable modal center value is obtained by averaging the clustering algorithm to ensure robustness. The calculation formula is: ； in, For the modal eigenvectors of group data; The mode change ratio matrix Compared with the standard modal change threshold Compare and construct the damage index Indicates the degree of damage to the structure: ； in, is the damage index, For the The modal change ratio matrix of the group data, for No. The standard modal change threshold of group data, , is the historical benchmark modal parameter The mean of is the historical benchmark modal parameter The standard deviation of , dynamically adjustable according to the actual allowable error; Combined with health status indicators and injury index The fuzzy logic reasoning system is used to determine the current state of the structure: ； in, is the fuzzy logic reasoning function, when When it is <0.98, an early warning is triggered, and it is determined that the seismic performance of the structure under the current working conditions is poor; the residual bearing capacity calculation and early warning module is used to calculate the residual seismic bearing capacity and generate graded early warning information based on health status indicators, design strength and maximum response values.

6. A building structure seismic performance monitoring system according to claim 5, characterized in that: The structural response data acquisition module includes: The sensor deployment unit is used to deploy triaxial acceleration sensors, fiber Bragg grating displacement meters, resistance strain gauges and MEMS tilt sensors at key nodes of the building structure to obtain acceleration , displacement ,strain With tilt angle data; Data preprocessing unit, used to perform wavelet denoising on the collected data and construct a unified response data set after standardization , and generate a timestamp-based The multidimensional response matrix ; Sampling control unit, setting sampling frequency [100, 500] Hz, which meets the frequency domain requirements for extracting low-order modal features of the structure.

7. A building structure seismic performance monitoring system according to claim 5, characterized in that: The modal identification and damage assessment module includes: Modal parameter identification unit, based on standard response data set , using an improved modal identification algorithm to extract the natural frequency of the building structure , damping ratio , main mode shape , forming the modal eigenvector ; The damage index calculation unit converts the modal eigenvector Compared with historical benchmark modal parameters Compare and calculate the modal change ratio and by comparing with the standard threshold Compare and get the damage index ; Health status assessment unit, using fuzzy logic reasoning function , combined with the injury index , modal change ratio and the main mode shape , output health status indicators , and judge whether to enter the warning state accordingly.

8. A building structure seismic performance monitoring system according to claim 5, characterized in that: The remaining bearing capacity calculation and early warning module includes: The residual bearing capacity calculation unit comprehensively considers the design strength of structural components based on the current damage state , maximum response value , current health status indicators , the residual seismic bearing capacity of the building structure : Safety threshold judgment unit, residual seismic bearing capacity of building structures and setting safety thresholds Compare and judge the current load safety status; A graded warning information generation unit generates a warning level based on the comparison results , its value is divided according to the following conditions: 。

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