Method for detecting seismic damage state of RC bridge pier locally reinforced by UHPC shell

Abstract

The application discloses a UHPC shell local reinforcement RC bridge pier earthquake damage state detection method, and belongs to the technical field of bridge structure health monitoring and post-earthquake damage assessment. It comprises: connecting and partitioning the combination interface of the UHPC shell and the RC bridge pier to represent, constructing the stress wave propagation path constraint relationship corresponding to each connecting partition, and outputting the propagation path constraint relationship set; based on the propagation path constraint relationship set, performing pre-earthquake path consistency active detection and post-earthquake path consistency active detection respectively, obtaining a pre-earthquake reference response library and a post-earthquake response signal set; based on the non-destructive reference path, performing propagation consistency correction on the post-earthquake response signal set, and combining the pre-earthquake reference response library to perform path level difference processing, and outputting a damage difference response; damage feature interpretation is performed on the damage difference response, and the damage state of each connecting partition is output; based on the damage state of each connecting partition, spatial fusion reconstruction is performed, and the overall earthquake damage state evaluation result of the UHPC shell local reinforcement RC bridge pier is generated.

Description

Technical Field

[0001] This application relates to the field of bridge structural health monitoring and post-earthquake damage assessment technology, and more specifically, to a method for detecting the seismic damage status of UHPC shell locally reinforced RC bridge piers. Background Technology

[0002] With the continuous expansion of my country's transportation infrastructure construction, a large number of bridge projects are located in areas with frequent seismic activity. As the main load-bearing and seismic-resistant components of bridge structures, the service safety of bridge piers directly affects the overall stability of the bridge structure and its post-earthquake traffic capacity. Reinforced concrete (RC) piers are widely used due to their advantages of convenient construction and good economy. However, under strong earthquakes, piers are prone to damage such as concrete cracking, steel yielding, interface peeling, and localized failure in the plastic hinge zone, leading to a significant decrease in structural load-bearing capacity and seismic performance. To improve the seismic performance and post-earthquake recovery capacity of piers, the local reinforcement technology of ultra-high performance concrete (UHPC) shells has gradually attracted attention. By setting UHPC shells in the key stress areas of piers, the crack resistance, energy dissipation capacity, and ductility of the piers can be effectively improved, thereby enhancing the seismic performance and durability of the piers.

[0003] However, after an earthquake, the interface between the UHPC shell and the RC pier often becomes a critical area for damage evolution. Due to differences between UHPC and ordinary concrete in terms of elastic modulus, wave impedance, and deformation compatibility, microcrack propagation, bond degradation, delamination, and localized peeling are easily observed at the interface under seismic loads. This type of damage typically first occurs within the structure or in concealed areas of the interface, making it difficult to accurately detect using traditional methods such as manual inspection and visual observation. Furthermore, the development of interface damage further affects the cooperative load-bearing performance between the UHPC shell and the RC pier, reducing the reinforcement effect and even triggering localized failure. Therefore, accurate detection and assessment of the damage state at the interface are of great significance.

[0004] Existing post-earthquake damage detection technologies for bridges mainly include manual inspection, strain monitoring, vibration mode identification, ultrasonic testing, and acoustic emission testing. Manual inspection relies primarily on apparent cracks and spalling phenomena, making it difficult to identify hidden internal damage. While overall vibration characteristic-based detection methods can reflect changes in structural stiffness, they have low sensitivity to local interface damage. Ultrasonic and stress wave detection technologies have good non-destructive testing capabilities, but existing methods typically analyze bridge piers as homogeneous structures, failing to fully consider the regional differences at the interface between the UHPC shell and the RC pier, and the influence of interface conditions on stress wave propagation paths. Furthermore, changes in environmental temperature, humidity, and material conditions before and after an earthquake can cause drift in stress wave propagation characteristics, easily leading to misinterpretations. Simultaneously, most existing methods focus on identifying single-point or localized damage, lacking the comprehensive assessment capability of the spatial distribution of interface damage and the overall damage extent of the bridge pier, making it difficult to meet the needs of rapid post-earthquake assessment and safety decision-making for locally reinforced RC piers with UHPC shells.

[0005] In summary, how to construct a reliable damage detection mechanism for the interface of locally reinforced RC piers with UHPC shells, and achieve accurate identification of interface damage, quantitative assessment of damage degree, and spatial reconstruction and comprehensive evaluation of overall damage status after earthquakes, while eliminating the influence of environmental and propagation path differences, has become an urgent technical problem to be solved. Summary of the Invention

[0006] To overcome a series of shortcomings in the existing technology, the purpose of this application is to provide a method for detecting the seismic damage state of locally reinforced UHPC shell RC bridge piers, comprising the following steps: The interface between the UHPC shell and the RC pier is characterized by connection partitioning. The stress wave propagation path constraint relationship corresponding to each connection partition is constructed, and the propagation path constraint relationship set is output. Based on the propagation path constraint relationship set, perform pre-earthquake path consistency active detection and post-earthquake path consistency active detection respectively to obtain the pre-earthquake benchmark response library and the post-earthquake response signal set; Based on the non-destructive reference path, the propagation consistency of the post-earthquake response signal set is corrected, and path-level differential processing is performed in combination with the pre-earthquake benchmark response library to output the damage difference response. Damage features are interpreted from the damage difference response, and the damage status of each connected partition is output. Spatial fusion reconstruction is performed based on the damage status of each connected partition to generate an overall seismic damage status assessment result for the UHPC shell locally reinforced RC pier.

[0007] In some embodiments, the method for characterizing the connection partition of the interface between the UHPC shell and the RC pier is as follows: Obtain the bond strength distribution information of the interface between the UHPC shell and the RC pier, and obtain the stress distribution information of the pier under the preset load conditions. Based on the bond strength distribution information and stress distribution information, the bonding interface is geometrically partitioned along the pier height direction to obtain multiple connection partitions; Based on the bonding strength level and stress concentration in each connection zone, the interfacial mechanical characteristic parameters of each connection zone are extracted, and the connection status level of each connection zone is determined based on the interfacial mechanical characteristic parameters, thereby dividing the key monitoring zone and the reference zone. Based on the interface mechanical characteristic parameters and connection status level of each connection zone, establish the stress wave propagation path constraint relationship corresponding to each connection zone. Establish the partition coordinate mapping relationship between each connection partition and the sensor number, and generate the connection partition representation results of the combined interface.

[0008] In some embodiments, the method for constructing stress wave propagation path constraint relationships is as follows: Determine the propagation path of stress waves within each connection zone and extract the propagation characteristic parameters corresponding to each propagation path; Based on the propagation characteristic parameters, construct a multidimensional propagation constraint model corresponding to each propagation path; Based on the multidimensional propagation constraint model corresponding to each propagation path, the propagation path constraint relationship between each propagation path is established. An index mapping of propagation path constraint relationships is established based on the propagation path number and the connection partition number, generating a set of stress wave propagation path constraint relationships corresponding to each connection partition.

[0009] In some embodiments, the methods for performing pre-earthquake path consistency active detection and post-earthquake path consistency active detection based on the propagation path constraint relationship set are as follows: Based on the set of propagation path constraint relationships, establish the stress wave propagation path network corresponding to each connected partition; Based on the propagation path constraint relationship corresponding to each propagation path, determine the combination of excitation parameters that matches each propagation path; Active stimulation is performed along each propagation path according to a preset timing sequence, and response signals corresponding to each propagation path are collected simultaneously. The response signals are synchronously preprocessed to obtain the path response signals corresponding to each propagation path; Based on the propagation path constraint relationship set, path consistency detection is performed on the response signals of each path, and an index association relationship is established between the path response signals and the propagation path number and the connection partition number. The path response signals obtained from pre-earthquake path consistency active detection are used to construct a pre-earthquake baseline response library, and the path response signals obtained from post-earthquake path consistency active detection are used to construct a post-earthquake response signal set.

[0010] In some embodiments, the method for propagation consistency correction of the post-earthquake response signal set based on a lossless reference path is as follows: Extract the response feature vector of the non-destructive reference path in the post-earthquake response signal set and match it with the corresponding response feature vector in the pre-earthquake benchmark response library; Based on the matching results, the response characteristic deviation of each lossless reference path is calculated, the propagation drift corresponding to each lossless reference path is determined, and path-level propagation drift correction coefficients are constructed. When there are multiple lossless reference paths, the path weights are determined based on the spatial proximity between the connection partition where each lossless reference path is located and the connection partition to be corrected, and the propagation drift correction coefficients of each path are weighted and fused to obtain the global correction coefficients. The response feature vectors of each propagation path in the post-earthquake response signal set, excluding the lossless reference path, are corrected using global correction coefficients to obtain the corrected response feature vectors. The global correction coefficients are updated using a sliding time window to adapt to the drift in propagation characteristics caused by changes in environmental conditions at different vibration stages.

[0011] In some embodiments, the method for path-level differential processing in conjunction with the pre-earthquake baseline response library is as follows: For each propagation path in the propagation path constraint relation set, the modified response feature vector is differentially calculated with the corresponding benchmark feature vector in the pre-earthquake benchmark response library according to the dimension to obtain the original differential feature vector. Based on the statistical fluctuation ranges corresponding to each feature dimension in the pre-earthquake baseline response database, the original differential feature vectors are normalized to obtain normalized differential feature vectors. Based on the historical statistical distribution of each feature dimension in the pre-earthquake baseline response database, the significance of the normalized difference feature vector is determined to obtain a set of significantly different dimensions. The normalized difference components corresponding to the set of significant difference dimensions are retained, and the normalized difference components corresponding to the non-significant difference dimensions are set to zero to obtain the damage difference response.

[0012] In some embodiments, the method for interpreting damage features from damage difference responses is as follows: Multidimensional damage characterization parameters are extracted from the damage difference response, including at least one of the following: energy attenuation rate characteristics, first wave arrival time delay characteristics, waveform correlation coefficient characteristics, and dominant frequency offset characteristics; Establish a mapping relationship between multidimensional damage characterization parameters and combined interface damage mechanisms; Based on the mapping relationship, multi-feature fusion analysis is performed on the connection partitions corresponding to each propagation path to identify the damage type and severity tendency of each connection partition, and to identify the composite damage mechanism of the corresponding partition when the multidimensional damage characterization parameters are abnormal. Based on the deviation of the multidimensional damage characterization parameters from the baseline fluctuation range, the damage type and severity of each connected partition are quantitatively characterized, and the damage feature interpretation results are obtained.

[0013] In some embodiments, the method for obtaining the damage status of each connection partition is as follows: The damage feature interpretation results corresponding to all propagation paths involved in each connection partition are summarized to form a partition-level damage feature set; The damage feature set of each partition is classified and determined based on the preset damage level classification standard to obtain the initial damage level of each connected partition. When the multipath determination results within the same connection partition are inconsistent, the damage status of the connection partition shall be determined according to the highest level principle. Based on the damage status of adjacent partitions, a consistency check and correction is performed on partitions containing only a single propagation path to obtain the final damage status of each connected partition.

[0014] In some embodiments, the method for spatial fusion reconstruction based on the damage state of each connectivity partition is as follows: Based on the interface mechanical characteristic parameters and connection state level of each connection zone, a structural importance coefficient is assigned to each connection zone. Among them, the plastic hinge zone, the bending deformation concentration zone and the stiffness change zone correspond to larger structural importance coefficients, while the other zones correspond to smaller structural importance coefficients. The final damage state of each connection partition is converted into a damage quantification value according to a preset mapping rule, and then weighted by combining the structural importance coefficient to obtain the weighted damage contribution value of each connection partition. Spatial interpolation is performed on the weighted damage contribution values ​​of adjacent connected partition boundary regions to construct a continuous spatial damage distribution field; Based on the continuous spatial damage distribution field, the damage distribution is spatially unfolded along the height and circumferential directions of the bridge pier to generate a two-dimensional or three-dimensional damage distribution map.

[0015] In some embodiments, the method for generating the overall seismic damage status assessment results of UHPC shell locally reinforced RC piers is as follows: Based on the continuous spatial damage distribution field, the weighted damage contribution values ​​of each connected partition are summarized to form an overall damage spatial feature set; Based on the proportion of the weighted damage contribution values ​​of each zone, a comprehensive damage index is obtained to characterize the overall damage level of the bridge pier. The comprehensive damage index is divided into preset ranges and mapped to corresponding safety treatment levels, which include normal use, restricted use, discontinued use, and special safety assessment levels. The comprehensive damage index, the damage status of the connecting zones, and the two-dimensional or three-dimensional damage distribution map are fused to generate the overall seismic damage status assessment result of the UHPC shell locally reinforced RC pier.

[0016] Compared with the prior art, this application has the following beneficial effects: This application addresses the challenges of accurately identifying post-earthquake interface damage and quantifying the spatial distribution of damage in locally reinforced RC piers with UHPC shells. By partitioning the interface between the UHPC shell and the RC pier, constructing stress wave propagation path constraints, and combining a pre-earthquake baseline response library, post-earthquake active detection, non-destructive reference path propagation consistency correction, and a multi-dimensional damage feature interpretation mechanism, it achieves accurate identification of the location, type, and extent of damage at the interface. Furthermore, through spatial fusion reconstruction of partitioned damage states and overall damage index assessment, the influence of environmental changes and propagation path differences on the detection results can be effectively eliminated, improving the accuracy, stability, and reliability of post-earthquake damage detection. This enables a visualized, quantitative, and global assessment of the seismic damage state of locally reinforced RC piers with UHPC shells, providing a reliable basis for determining the post-earthquake safety of piers and making maintenance decisions. Attached Figure Description

[0017] Figure 1 This is an overall flowchart of the seismic damage state detection method for locally reinforced RC bridge piers with UHPC shell provided in Embodiment 1 of the present invention; Figure 2 This is a flowchart of the method for constructing the interface connection partition characterization and stress wave propagation path constraint relationship provided in Embodiment 2 of the present invention. Figure 1 The specific implementation process of step S101; Figure 3 The flowcharts for the path consistency active detection and non-destructive reference path determination, propagation consistency correction and path level difference processing, damage feature interpretation and connection partition damage state determination, spatial fusion reconstruction and overall evaluation result generation methods provided in Embodiments 3 and 4 of the present invention are shown, and two optional steps, environmental compensation processing and reinforcement decision generation, are illustrated. Figure 1 The specific implementation process of steps S102 to S105. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some embodiments of this invention, but not all embodiments.

[0019] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The embodiments and directional terms described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] Example 1 Reference Figure 1 As shown in the figure, this embodiment provides a method for detecting the seismic damage state of a locally reinforced RC bridge pier with a UHPC shell, which is used to achieve overall detection and evaluation of the seismic damage state at the interface between the UHPC shell and the RC bridge pier. The method specifically includes the following steps: S101: Characterize the connection partition of the interface between the UHPC shell and the RC pier, construct the stress wave propagation path constraint relationship corresponding to each connection partition, and output the propagation path constraint relationship set; S102: Based on the propagation path constraint relationship set, perform pre-earthquake path consistency active detection and post-earthquake path consistency active detection respectively to obtain the pre-earthquake benchmark response library and the post-earthquake response signal set; S103: Based on the non-destructive reference path, the propagation consistency of the post-earthquake response signal set is corrected, and path-level differential processing is performed in combination with the pre-earthquake benchmark response library to output the damage difference response. S104: Interpret the damage characteristics of the damage difference response and output the damage status of each connected partition; S105: Based on the damage status of each connected partition, spatial fusion reconstruction is performed to generate the overall seismic damage status assessment results of the UHPC shell locally reinforced RC pier.

[0022] The seismic damage state detection method for locally reinforced RC bridge piers with UHPC shells provided in this application first characterizes the interface between the UHPC shell and the RC bridge pier by dividing it into connection zones and establishing stress wave propagation path constraints for each connection zone, ensuring that the detection process matches the actual stress and connection characteristics of the interface. Then, it acquires pre- and post-earthquake stress wave response information, and reduces the impact of propagation path differences, material dispersion, and external environmental changes on the detection results through non-destructive reference path correction and path differential analysis. Furthermore, it extracts damage characteristics of each connection zone by combining damage difference responses, determines the corresponding damage state, and performs spatial fusion analysis on the damage states of each zone to obtain the overall seismic damage state of the bridge pier. This method can effectively identify the damage at the interface between the UHPC shell and the RC bridge pier, improve the accuracy and completeness of post-earthquake damage detection results, and provide a basis for post-earthquake safety assessment and maintenance of locally reinforced RC bridge piers with UHPC shells.

[0023] Example 2 Reference Figure 2 As shown, based on Embodiment 1, this embodiment further improves upon... Figure 1 The specific construction method of the connection partition characterization method and the stress wave propagation path constraint relationship described in step S101 will be further explained, corresponding to... Figure 2 Steps S201 to S206 specifically include the following steps: The method for characterizing the connection zone at the interface between the UHPC shell and the RC pier is as follows: S201: Obtain the bond strength distribution information of the interface between the UHPC shell and the RC pier, and obtain the stress distribution information of the pier under the preset load conditions. S202: Based on the bond strength distribution information and stress distribution information, the bonding interface is geometrically partitioned along the pier height direction to obtain multiple connection partitions; S203: Based on the bonding strength level and stress concentration degree in each connection partition, extract the interface mechanical characteristic parameters of each connection partition, and determine the connection status level of each connection partition based on the interface mechanical characteristic parameters, thereby dividing the key monitoring partition and the reference partition; based on the interface mechanical characteristic parameters and connection status level of each connection partition, establish the stress wave propagation path constraint relationship corresponding to each connection partition; establish the partition coordinate mapping relationship between each connection partition and the sensor number, and generate the connection partition characterization result of the interface.

[0024] The connection partitioning characterization method described in this application first obtains the bond strength distribution at the interface between the UHPC shell and the RC pier, as well as the stress distribution of the pier under a preset load condition. Based on this, the interface is partitioned along the pier height, so that each partition reflects the stress and connection characteristics at different locations. Then, based on the bond strength level and stress concentration of each partition, the corresponding connection state level is determined, and key monitoring partitions and reference partitions are distinguished. Furthermore, stress wave propagation path constraints are established based on the mechanical characteristics of each partition, and a correspondence between the partitions and sensors is established. Through this method, a reasonable division of the interface detection area can be achieved, ensuring that the stress wave propagation path matches the actual connection state of the interface, providing a basis for subsequent damage information extraction and damage state determination, and improving the reliability of the interface damage detection results.

[0025] The method for constructing the stress wave propagation path constraint relationship is as follows: S204: Determine the propagation path of stress waves within each connection zone and extract the propagation characteristic parameters corresponding to each propagation path; S205: Based on the propagation characteristic parameters, construct a multidimensional propagation constraint model corresponding to each propagation path; based on the multidimensional propagation constraint model corresponding to each propagation path, establish the propagation path constraint relationship between each propagation path; S206: Establish an index mapping of propagation path constraint relationships based on the propagation path number and the connection partition number, and generate a set of stress wave propagation path constraint relationships corresponding to each connection partition.

[0026] The stress wave propagation path constraint relationship construction method described in this application determines the stress wave propagation path within each connecting partition and extracts corresponding propagation characteristic parameters, enabling the stress wave propagation process to correspond to the structural characteristics and mechanical state of the interface. By constructing a multi-dimensional propagation constraint model corresponding to each propagation path and establishing constraint relationships between different propagation paths, the actual propagation law of stress waves within the interface can be reflected. Furthermore, an index mapping is established based on the correspondence between propagation paths and connecting partitions, forming a set of propagation path constraint relationships for each connecting partition. Through this method, a unified association between propagation path information and connecting partition information can be achieved, providing a basis for subsequent stress wave response analysis and damage localization, and improving the accuracy and reliability of interface damage identification.

[0027] Example 3 Reference Figure 3 As shown, based on Embodiment 1 and Embodiment 2, this embodiment further improves upon them. Figure 1 The active detection method for pre-earthquake and post-earthquake path consistency and the method for determining the non-destructive reference path described in step S102 (corresponding to...) Figure 3 (Steps S301 to S303), and Figure 1The propagation consistency correction method and path-level differential processing method described in step S103 (corresponding to) Figure 3 Further explanation is provided for steps S304 to S305.

[0028] The methods for performing pre-earthquake path consistency active detection and post-earthquake path consistency active detection based on the propagation path constraint relationship set are as follows: S301: Based on the propagation path constraint relationship set, establish the stress wave propagation path network corresponding to each connection partition; based on the propagation path constraint relationship corresponding to each propagation path, determine the excitation parameter combination matching each propagation path; execute active excitation along each propagation path according to the preset timing sequence, and synchronously collect the response signal corresponding to each propagation path; S302: Perform synchronous preprocessing on the response signals to obtain the path response signals corresponding to each propagation path; based on the propagation path constraint relationship set, perform path consistency detection on each path response signal, and establish an index association relationship between the path response signal and the propagation path number and the connection partition number; construct the path response signals obtained by pre-earthquake path consistency active detection into a pre-earthquake baseline response library, and construct the path response signals obtained by post-earthquake path consistency active detection into a post-earthquake response signal set.

[0029] The pre-earthquake path consistency active detection and post-earthquake path consistency active detection methods described in this application first establish a stress wave propagation path network corresponding to each connecting zone based on the propagation path constraint relationship set, and determine matching excitation parameter combinations for different propagation paths to ensure the consistency of detection conditions for each propagation path; then, active excitation is executed according to a preset time sequence and response signals are collected synchronously, so that the response information of each propagation path can accurately correspond to its corresponding connecting zone; on this basis, the collected response signals are synchronously preprocessed and path consistency detected, abnormal response data that do not meet the propagation constraint conditions are eliminated, and the correspondence between response signals and propagation paths and connecting zones is established; finally, a pre-earthquake benchmark response library and a post-earthquake response signal set are formed, providing a unified data foundation for subsequent pre-earthquake and post-earthquake response difference analysis and damage state identification, thereby improving the reliability and comparability of the combined interface earthquake damage detection results.

[0030] The method for determining the lossless reference path is as follows: S303: Obtain the structural deformation monitoring results corresponding to each propagation path, and screen candidate reference paths based on the structural deformation monitoring results; when the structural deformation monitoring results are missing or incomplete, screen candidate reference paths based on the relative positional relationship between the propagation path and the vulnerable area; evaluate the stability of the path response signal corresponding to each candidate reference path, and determine the non-destructive reference path based on the degree of response deviation and consistency of repeated detection of each candidate reference path.

[0031] The non-destructive reference path determination method described in this application obtains structural deformation monitoring results corresponding to each propagation path and filters candidate reference paths based on the degree of structural deformation, prioritizing propagation paths less affected by seismic forces. When structural deformation monitoring data is missing or incomplete, supplementary filtering is performed by considering the positional relationship between the propagation path and vulnerable areas, ensuring the continuity and applicability of the reference path selection process. Furthermore, the stability of the path response signals corresponding to the candidate reference paths is evaluated, and the non-destructive reference path is determined by considering the degree of response deviation and consistency of repeated detections. Through this method, reference paths with relatively stable states and low probability of damage can be obtained, providing a reliable benchmark for subsequent post-earthquake response signal propagation consistency correction and damage difference analysis, thereby improving the accuracy and stability of damage identification results.

[0032] The method for propagation consistency correction of post-earthquake response signal sets based on lossless reference paths is as follows: S304: Extract the response feature vector of the lossless reference path in the post-earthquake response signal set and match it with the corresponding response feature vector in the pre-earthquake benchmark response library; calculate the response feature deviation of each lossless reference path based on the matching results, determine the propagation drift corresponding to each lossless reference path, and construct path-level propagation drift correction coefficients; when there are multiple lossless reference paths, determine the path weights according to the spatial proximity relationship between the connection partition where each lossless reference path is located and the connection partition to be corrected, and perform weighted fusion of the propagation drift correction coefficients of each path to obtain global correction coefficients; use the global correction coefficients to correct the response feature vectors of each propagation path in the post-earthquake response signal set except for the lossless reference paths to obtain the corrected response feature vectors; perform sliding updates of the global correction coefficients based on time windows to adapt to the propagation characteristic drift caused by changes in environmental conditions at different vibration stages.

[0033] The method described in this application for propagation consistency correction of post-earthquake response signal sets based on non-destructive reference paths matches the post-earthquake response characteristics of the non-destructive reference paths with the pre-earthquake baseline response characteristics to determine the propagation drift caused by environmental changes, sensor state changes, and propagation condition changes, and constructs propagation drift correction coefficients accordingly. When multiple non-destructive reference paths exist, the propagation drift correction coefficients are weighted and fused based on the spatial proximity between the connecting partitions where the non-destructive reference paths are located and the connecting partitions to be corrected, to obtain global correction coefficients. These global correction coefficients are then used to uniformly correct the post-earthquake response characteristics of each propagation path, and the correction coefficients are dynamically updated through a time window. This approach reduces the impact of response differences caused by non-damaging factors on the detection results, maintains good comparability of response signals acquired at different stages, provides a more reliable data foundation for subsequent damage feature extraction and damage state determination, and thus improves the accuracy and stability of earthquake damage identification results.

[0034] The method for path-level differential processing based on the pre-earthquake baseline response database is as follows: S305: For each propagation path in the propagation path constraint relationship set, the corrected response feature vector and the corresponding benchmark feature vector in the pre-earthquake benchmark response library are differentially processed according to dimension to obtain the original differential feature vector; based on the statistical fluctuation range corresponding to each feature dimension in the pre-earthquake benchmark response library, the original differential feature vector is normalized to obtain the normalized differential feature vector; based on the historical statistical distribution of each feature dimension in the pre-earthquake benchmark response library, the significance of the normalized differential feature vector is determined to obtain the set of significantly different dimensions; the normalized differential components corresponding to the set of significantly different dimensions are retained, and the normalized differential components corresponding to the non-significantly different dimensions are set to zero to obtain the damage difference response.

[0035] The method described in this application, which combines a pre-earthquake baseline response database with path-level difference processing, obtains the original difference information characterizing the pre-earthquake and post-earthquake state changes by performing a dimension-by-dimensional difference analysis between the corrected response feature vector and the corresponding baseline feature vector in the database. Further, it normalizes the results by incorporating the statistical fluctuation range of each feature dimension under the pre-earthquake state, reducing the impact of differences in different feature dimensions and natural fluctuations on the analysis results. Subsequently, it determines the significance of the difference results based on the historical statistical distribution of each feature dimension, selecting significant difference dimensions that reflect structural state changes and suppressing insignificant difference information caused by random fluctuations or noise. Through the above processing, a damage difference response is obtained, effectively preserving damage-related features and providing a basis for subsequent damage feature interpretation and damage state identification, thereby improving the accuracy and anti-interference capability of damage detection results.

[0036] Example 4 Combination Figure 3 As shown, based on Examples 1 to 3, this example further... Figure 1 The damage feature interpretation method described in step S104 (corresponding to) Figure 3 Step S306) and the method for obtaining the damage status of the connected partition (corresponding to) Figure 3 (Step S307) Figure 1 The spatial fusion and reconstruction method described in step S105 (corresponding to) Figure 3 Step S308) and the method for generating the overall evaluation results (corresponding to) Figure 3 (Middle step S309), and Figure 3 The preferred environmental compensation treatment step (S310) and the reinforcement decision generation step (S311) shown in the figure are further explained.

[0037] The method for interpreting damage characteristics from differential damage responses is as follows: S306: Extract multidimensional damage characterization parameters from the damage difference response, including at least one of energy attenuation rate characteristics, first wave arrival delay characteristics, waveform correlation coefficient characteristics, and dominant frequency offset characteristics; establish a mapping relationship between multidimensional damage characterization parameters and interface damage mechanisms; based on the mapping relationship, perform multi-feature fusion analysis on the connecting partitions corresponding to each propagation path to identify the damage type and severity tendency of each connecting partition, and identify the composite damage mechanism of the corresponding partition when the multidimensional damage characterization parameters are abnormal; based on the deviation of the multidimensional damage characterization parameters from the benchmark fluctuation range, quantify the damage type and damage severity of each connecting partition to obtain damage feature interpretation results.

[0038] The damage feature interpretation method described in this application extracts multi-dimensional damage characterization parameters, such as energy attenuation rate, first wave arrival delay, waveform correlation coefficient, and dominant frequency shift, from the damage difference response. This allows for the reflection of changes in the propagation characteristics of the interface from different perspectives. By establishing a correspondence between the multi-dimensional damage characterization parameters and the damage mechanism of the interface, the detection results can correspond to the actual damage form. Furthermore, by combining and analyzing the detection results corresponding to multiple propagation paths, the damage type and damage development degree of each connecting partition are identified, and potential composite damage states are identified when multiple features show anomalies simultaneously. Simultaneously, the damage type and severity are quantitatively characterized based on the deviation of each damage characterization parameter from the baseline fluctuation range. Through these methods, the accuracy and interpretability of damage identification results can be improved, enabling a refined assessment of the damage state of the interface and providing a basis for subsequent overall damage state determination.

[0039] The method for obtaining the damage status of each connected partition is as follows: S307: Summarize the damage feature interpretation results corresponding to all propagation paths involved in each connected partition to form a partition-level damage feature set; classify the partition-level damage feature set according to the preset damage level classification standard to obtain the initial damage level of each connected partition; when the multi-path judgment results within the same connected partition are inconsistent, determine the damage state of the connected partition according to the highest level principle; perform consistency verification and correction on partitions containing only a single propagation path based on the damage states of adjacent partitions to obtain the final damage state corresponding to each connected partition.

[0040] The method for obtaining the damage status of each connection partition described in this application summarizes the damage feature interpretation results corresponding to all propagation paths within the same connection partition to form a partition-level damage feature set that reflects the overall state of the region. Further, the partition-level damage feature set is graded according to a preset damage level classification standard to obtain the initial damage level of each connection partition. When there are differences in the judgment results of different propagation paths within the same connection partition, the highest level principle is used to determine the damage status of that connection partition to avoid averaging out severe local damage and causing missed detections. Simultaneously, the damage status of adjacent partitions is combined to perform consistency verification and correction on connection partitions containing only a single propagation path. Through this method, the detection results of multiple propagation paths can be comprehensively utilized, improving the stability and reliability of connection partition damage status determination, and making the final obtained damage status more consistent with the actual damage situation of the interface.

[0041] The method for spatial fusion and reconstruction based on the damage state of each connectivity partition is as follows: S308: Based on the interface mechanical characteristic parameters and connection status level of each connection zone, assign a structural importance coefficient to each connection zone. The plastic hinge zone, bending deformation concentration zone, and stiffness abrupt change zone correspond to larger structural importance coefficients, while the other zones correspond to smaller structural importance coefficients. Convert the final damage state of each connection zone into a damage quantification value according to a preset mapping rule, and perform weighted processing in combination with the structural importance coefficient to obtain the weighted damage contribution value of each connection zone. Perform spatial interpolation on the weighted damage contribution value of the boundary area between adjacent connection zones to construct a continuous spatial damage distribution field. Based on the continuous spatial damage distribution field, spatially unfold along the pier height direction and circumferential direction to generate a two-dimensional damage distribution map or a three-dimensional damage distribution map.

[0042] The method described in this application, which spatially reconstructs damage based on the damage state of each connection zone, assigns different structural importance coefficients to each connection zone by combining the interface mechanical characteristic parameters and connection state level. This gives higher weight to key components such as plastic hinge zones, bending deformation concentration zones, and stiffness abrupt change zones in the overall assessment. Furthermore, the damage state of each connection zone is converted into corresponding damage quantification values, and a weighted damage contribution value is calculated based on the structural importance coefficients, ensuring a reasonable representation of the damage impact of different regions. Subsequently, spatial interpolation is performed on the boundary regions of adjacent connection zones to construct a continuous damage distribution field, reducing the impact of zone boundaries on the continuity of damage assessment results. Based on this, the damage distribution field is spatially unfolded along the pier height and circumferential directions to form two-dimensional or three-dimensional damage distribution maps. Through this method, the damage distribution characteristics and damage development degree of the interface between the UHPC shell and the RC pier can be more intuitively reflected, improving the completeness and visualization of the overall damage state assessment results and providing a basis for post-earthquake safety evaluation and maintenance decisions for piers.

[0043] The method for generating the overall seismic damage status assessment results of UHPC shell locally reinforced RC piers is as follows: S309: Based on the continuous spatial damage distribution field, the weighted damage contribution values ​​of each connecting zone are summarized to form an overall damage spatial feature set; according to the proportion of the weighted damage contribution values ​​of each zone, a comprehensive damage index is obtained to characterize the overall damage degree of the pier; the comprehensive damage index is divided according to a preset interval and mapped to the corresponding safety treatment level, which includes normal use, restricted use, cessation of use and special safety assessment level; the comprehensive damage index, the damage status of the connecting zone and the two-dimensional damage distribution map or the three-dimensional damage distribution map are fused to generate the overall seismic damage status assessment result of the UHPC shell locally reinforced RC pier.

[0044] The proposed method for assessing the overall seismic damage status of UHPC shell-reinforced RC piers involves summarizing and analyzing the weighted damage contribution values ​​of each connecting zone in a continuous spatial damage distribution field to form a set of spatial damage characteristics characterizing the overall damage to the pier. Furthermore, based on the distribution characteristics and proportions of the damage contribution values ​​of each connecting zone, a comprehensive damage index is calculated to quantitatively evaluate the overall damage level of the pier. Simultaneously, according to a preset safety level classification standard, the comprehensive damage index is mapped to a corresponding safety treatment level, providing a basis for determining the post-earthquake serviceability of the pier. On this basis, the comprehensive damage index, the damage status of each connecting zone, and the two-dimensional or three-dimensional damage distribution results are integrated and displayed, reflecting not only the overall damage level of the pier but also visually presenting the spatial distribution location and development range of the damage. This method achieves a unified assessment of local damage information at the interface between the UHPC shell and the RC pier, improving the completeness, intuitiveness, and engineering application value of the post-earthquake damage assessment results, and providing a technical basis for post-earthquake safety assessment, maintenance and reinforcement, and operational decisions for piers.

[0045] Furthermore, the detection method also includes an environmental compensation treatment step, specifically: S310: During the normal operation of the UHPC shell locally reinforced RC pier, the response characteristics of each propagation path under different environmental conditions are collected under different seasons and day / night conditions, and the corresponding ambient temperature and relative humidity data are recorded simultaneously; based on the response characteristics, ambient temperature and relative humidity data, a correlation function is established between the travel time parameters and attenuation parameters of each propagation path and the environmental parameters; when performing pre-earthquake path consistency active detection or post-earthquake path consistency active detection, the environmental impact correction amount is calculated through the correlation function according to the real-time ambient temperature and relative humidity; the original response characteristics are compensated and corrected based on the environmental impact correction amount to obtain the corrected response characteristics, and propagation consistency correction and path level difference processing are performed based on the corrected response characteristics.

[0046] The environmental compensation processing method described in this application collects response characteristics of various propagation paths under different seasons and day / night conditions during the normal operation of the bridge pier, and simultaneously acquires ambient temperature and relative humidity data to establish a correspondence between stress wave propagation characteristics and environmental conditions. Furthermore, it constructs a correlation function between travel time parameters, attenuation parameters, and environmental parameters, enabling a quantitative characterization of the impact of environmental factors on stress wave propagation characteristics. During pre-earthquake or post-earthquake detection, the environmental impact correction is calculated based on real-time ambient temperature and relative humidity, and the original response characteristics are compensated accordingly, thereby reducing the fluctuations in propagation characteristics caused by environmental factors such as temperature and humidity changes. Based on this, propagation consistency correction and path-level differential processing are performed using the corrected response characteristics, ensuring that subsequent damage identification reflects more the structural state changes rather than the impact of environmental changes. Through this approach, the consistency and comparability of detection results under different environmental conditions can be improved, the impact of environmental interference on damage identification accuracy can be reduced, and the reliability of seismic damage state detection results for locally reinforced RC bridge piers with UHPC shells can be further enhanced.

[0047] Furthermore, the detection method also includes a hardening decision generation step, specifically: S311: Based on the damage status and structural importance coefficient of each connection partition, calculate the reinforcement priority score of each connection partition; sort the connection partitions from high to low reinforcement priority scores to generate a reinforcement treatment order list; for connection partitions whose reinforcement priority scores exceed the preset reinforcement trigger threshold, determine the damage type based on their damage feature interpretation results and generate the corresponding reinforcement treatment plan; when there are multiple damage types in the same connection partition, determine the reinforcement treatment order corresponding to each damage type; integrate the reinforcement treatment order list and the corresponding reinforcement treatment plan to generate reinforcement decision support information and output it.

[0048] The reinforcement decision generation method described in this application comprehensively assesses the damage level and structural impact of different areas by combining the damage status and structural importance coefficients of each connection zone, thus determining the reinforcement priority for each connection zone. Furthermore, it establishes a reinforcement treatment sequence based on the reinforcement priority, ensuring that limited maintenance resources are prioritized for critical damaged areas. For connection zones that meet the preset reinforcement conditions, it identifies specific damage types based on damage feature interpretation results and matches corresponding reinforcement treatment measures, ensuring that the reinforcement plan corresponds to the actual damage situation. When multiple damage types exist in the same connection zone, it further determines the order of treatment for each type of damage to reduce mutual influence between different reinforcement measures. Based on this, it integrates the reinforcement treatment sequence with the corresponding reinforcement plan to form reinforcement decision support information. Through this method, damage detection results can be directly transformed into treatment suggestions with engineering guidance significance, improving the pertinence and implementation efficiency of post-earthquake maintenance and reinforcement work, and providing a basis for the rapid post-earthquake treatment and safe restoration of UHPC shell locally reinforced RC bridge piers.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting the seismic damage state of a RC bridge pier locally reinforced by a UHPC shell, characterized in that, Includes the following steps: The interface between the UHPC shell and the RC pier is characterized by connection partitioning. The stress wave propagation path constraint relationship corresponding to each connection partition is constructed, and the propagation path constraint relationship set is output. Based on the propagation path constraint relationship set, perform pre-earthquake path consistency active detection and post-earthquake path consistency active detection respectively to obtain the pre-earthquake benchmark response library and the post-earthquake response signal set; Based on the non-destructive reference path, the propagation consistency of the post-earthquake response signal set is corrected, and path-level differential processing is performed in combination with the pre-earthquake benchmark response library to output the damage difference response. Damage features are interpreted from the damage difference response, and the damage status of each connected partition is output. Spatial fusion and reconstruction are performed based on the damage status of each connected partition to generate an overall seismic damage status assessment result for the UHPC shell locally reinforced RC pier.

2. The detection method according to claim 1, characterized in that, The method for characterizing the connection zone of the interface between the UHPC shell and the RC pier is as follows: Obtain the bond strength distribution information of the interface between the UHPC shell and the RC pier, and obtain the stress distribution information of the pier under the preset load conditions. Based on the bond strength distribution information and stress distribution information, the bonding interface is geometrically partitioned along the pier height direction to obtain multiple connection partitions; Based on the bonding strength level and stress concentration in each connection zone, the interfacial mechanical characteristic parameters of each connection zone are extracted, and the connection status level of each connection zone is determined based on the interfacial mechanical characteristic parameters, thereby dividing the key monitoring zone and the reference zone. Based on the interface mechanical characteristic parameters and connection status level of each connection zone, establish the stress wave propagation path constraint relationship corresponding to each connection zone. Establish the partition coordinate mapping relationship between each connection partition and the sensor number, and generate the connection partition representation results of the combined interface.

3. The detection method according to claim 1, characterized in that, The method for constructing the stress wave propagation path constraint relationship is as follows: Determine the propagation path of stress waves within each connection zone and extract the propagation characteristic parameters corresponding to each propagation path; Based on the propagation characteristic parameters, construct a multidimensional propagation constraint model corresponding to each propagation path; Based on the multidimensional propagation constraint model corresponding to each propagation path, the propagation path constraint relationship between each propagation path is established. An index mapping of propagation path constraint relationships is established based on the propagation path number and the connection partition number, generating a set of stress wave propagation path constraint relationships corresponding to each connection partition.

4. The detection method according to claim 3, characterized in that, The methods for performing pre-earthquake path consistency active detection and post-earthquake path consistency active detection based on the propagation path constraint relationship set are as follows: Based on the set of propagation path constraint relationships, establish the stress wave propagation path network corresponding to each connected partition; Based on the propagation path constraint relationship corresponding to each propagation path, determine the combination of excitation parameters that matches each propagation path; Active stimulation is performed along each propagation path according to a preset timing sequence, and response signals corresponding to each propagation path are collected simultaneously. The response signals are synchronously preprocessed to obtain the path response signals corresponding to each propagation path; Based on the propagation path constraint relationship set, path consistency detection is performed on the response signals of each path, and an index association relationship is established between the path response signals and the propagation path number and the connection partition number. The path response signals obtained from pre-earthquake path consistency active detection are used to construct a pre-earthquake baseline response library, and the path response signals obtained from post-earthquake path consistency active detection are used to construct a post-earthquake response signal set.

5. The detection method according to claim 1, characterized in that, The method for propagation consistency correction of post-earthquake response signal sets based on lossless reference paths is as follows: Extract the response feature vector of the non-destructive reference path in the post-earthquake response signal set and match it with the corresponding response feature vector in the pre-earthquake benchmark response library; Based on the matching results, the response characteristic deviation of each lossless reference path is calculated, the propagation drift corresponding to each lossless reference path is determined, and path-level propagation drift correction coefficients are constructed. When there are multiple lossless reference paths, the path weights are determined based on the spatial proximity between the connection partition where each lossless reference path is located and the connection partition to be corrected, and the propagation drift correction coefficients of each path are weighted and fused to obtain the global correction coefficients. The response feature vectors of each propagation path in the post-earthquake response signal set, excluding the lossless reference path, are corrected using global correction coefficients to obtain the corrected response feature vectors. The global correction coefficients are updated using a sliding time window to adapt to the drift in propagation characteristics caused by changes in environmental conditions at different vibration stages.

6. The detection method according to claim 5, characterized in that, The method for path-level differential processing based on the pre-earthquake baseline response database is as follows: For each propagation path in the propagation path constraint relation set, the modified response feature vector is differentially calculated with the corresponding benchmark feature vector in the pre-earthquake benchmark response library according to the dimension to obtain the original differential feature vector. Based on the statistical fluctuation ranges corresponding to each feature dimension in the pre-earthquake baseline response database, the original differential feature vectors are normalized to obtain normalized differential feature vectors. Based on the historical statistical distribution of each feature dimension in the pre-earthquake baseline response database, the significance of the normalized difference feature vector is determined to obtain a set of significantly different dimensions. The normalized difference components corresponding to the set of significant difference dimensions are retained, and the normalized difference components corresponding to the non-significant difference dimensions are set to zero to obtain the damage difference response.

7. The detection method according to claim 1, characterized in that, The method for interpreting damage characteristics from differential damage responses is as follows: Multidimensional damage characterization parameters are extracted from the damage difference response, including at least one of the following: energy attenuation rate characteristics, first wave arrival time delay characteristics, waveform correlation coefficient characteristics, and dominant frequency offset characteristics; Establish a mapping relationship between multidimensional damage characterization parameters and combined interface damage mechanisms; Based on the mapping relationship, multi-feature fusion analysis is performed on the connection partitions corresponding to each propagation path to identify the damage type and severity tendency of each connection partition, and to identify the composite damage mechanism of the corresponding partition when the multidimensional damage characterization parameters are abnormal. Based on the deviation of the multidimensional damage characterization parameters from the baseline fluctuation range, the damage type and severity of each connected partition are quantitatively characterized, and the damage feature interpretation results are obtained.

8. The detection method according to claim 7, characterized in that, The method for obtaining the damage status of each connected partition is as follows: The damage feature interpretation results corresponding to all propagation paths involved in each connection partition are summarized to form a partition-level damage feature set; The damage feature set of each partition is classified and determined based on the preset damage level classification standard to obtain the initial damage level of each connected partition. When the multipath determination results within the same connection partition are inconsistent, the damage status of the connection partition shall be determined according to the highest level principle. Based on the damage status of adjacent partitions, a consistency check and correction is performed on partitions containing only a single propagation path to obtain the final damage status of each connected partition.

9. The detection method according to claim 8, characterized in that, The method for spatial fusion and reconstruction based on the damage state of each connectivity partition is as follows: Based on the interface mechanical characteristic parameters and connection state level of each connection zone, a structural importance coefficient is assigned to each connection zone. Among them, the plastic hinge zone, the bending deformation concentration zone and the stiffness change zone correspond to larger structural importance coefficients, while the other zones correspond to smaller structural importance coefficients. The final damage state of each connection partition is converted into a damage quantification value according to a preset mapping rule, and then weighted by combining the structural importance coefficient to obtain the weighted damage contribution value of each connection partition. Spatial interpolation is performed on the weighted damage contribution values ​​of adjacent connected partition boundary regions to construct a continuous spatial damage distribution field; Based on the continuous spatial damage distribution field, the damage distribution is spatially unfolded along the height and circumferential directions of the bridge pier to generate a two-dimensional or three-dimensional damage distribution map.

10. The detection method according to claim 9, characterized in that, The method for generating the overall seismic damage status assessment results of UHPC shell locally reinforced RC piers is as follows: Based on the continuous spatial damage distribution field, the weighted damage contribution values ​​of each connected partition are summarized to form an overall damage spatial feature set; Based on the proportion of the weighted damage contribution values ​​of each zone, a comprehensive damage index is obtained to characterize the overall damage level of the bridge pier. The comprehensive damage index is divided into preset ranges and mapped to corresponding safety treatment levels, which include normal use, restricted use, discontinued use, and special safety assessment levels. The comprehensive damage index, the damage status of the connecting zones, and the two-dimensional or three-dimensional damage distribution map are fused to generate the overall seismic damage status assessment result of the UHPC shell locally reinforced RC pier.

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