In this paper, a long‐lasting phosphorescent microcapsule based on in‐situ polymerization method is proposed for damage sensing. The successful microencapsulation of core material was evaluated by a Fourier transform infrared spectrometer and an energy dispersive spectrometer. The results demonstrated that the long‐lasting phosphorescent microcapsules prepared with urea‐formaldehyde resin shell can make the microcapsules resistant to the temperature of 170°C. The long‐lasting phosphorescent microcapsules can maintain excellent phosphorescence intensity before being heated to 170°C and after being excited by ultraviolet light. Even after being heated at the limit working temperature for 12 h, they can still maintain phosphorescence emission for more than 10 min after being excited by ultraviolet light. When cracks occur on the surface of the material, the microcapsules are broken and phosphorescence is emitted at the cracks under the irradiation of ultraviolet light. The microcapsules applied to the surface of concrete specimens still had good damage expression effects under different environmental brightness conditions. It provides a new method in the field of concrete crack monitoring based on microcapsule damage sensing materials.
{"title":"Long‐lasting phosphorescent microcapsules based on in‐situ polymerization method for damage sensing","authors":"Haohui Zhang, Yao Li, Qing Wang, Ya-Yuan Zhao","doi":"10.1002/stc.3131","DOIUrl":"https://doi.org/10.1002/stc.3131","url":null,"abstract":"In this paper, a long‐lasting phosphorescent microcapsule based on in‐situ polymerization method is proposed for damage sensing. The successful microencapsulation of core material was evaluated by a Fourier transform infrared spectrometer and an energy dispersive spectrometer. The results demonstrated that the long‐lasting phosphorescent microcapsules prepared with urea‐formaldehyde resin shell can make the microcapsules resistant to the temperature of 170°C. The long‐lasting phosphorescent microcapsules can maintain excellent phosphorescence intensity before being heated to 170°C and after being excited by ultraviolet light. Even after being heated at the limit working temperature for 12 h, they can still maintain phosphorescence emission for more than 10 min after being excited by ultraviolet light. When cracks occur on the surface of the material, the microcapsules are broken and phosphorescence is emitted at the cracks under the irradiation of ultraviolet light. The microcapsules applied to the surface of concrete specimens still had good damage expression effects under different environmental brightness conditions. It provides a new method in the field of concrete crack monitoring based on microcapsule damage sensing materials.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77923500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The presence of moisture in historic buildings, especially from rising damp, is extremely widespread and severe, causing materials' deterioration, internal discomfort and bad thermal insulation of external walls. Although this phenomenon is widely studied in the literature, the available solutions are frequently only partially effective, also due to the lack of reliable and compatible techniques to monitor the amount of moisture inside porous building materials, especially in heritage buildings where multiple restrictions exist.
{"title":"A new sensorized ceramic plug for the remote monitoring of moisture in historic masonry walls: First results from laboratory and onsite testing","authors":"E. Franzoni, M. Bassi","doi":"10.1002/stc.3126","DOIUrl":"https://doi.org/10.1002/stc.3126","url":null,"abstract":"The presence of moisture in historic buildings, especially from rising damp, is extremely widespread and severe, causing materials' deterioration, internal discomfort and bad thermal insulation of external walls. Although this phenomenon is widely studied in the literature, the available solutions are frequently only partially effective, also due to the lack of reliable and compatible techniques to monitor the amount of moisture inside porous building materials, especially in heritage buildings where multiple restrictions exist.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82342741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This is a study on a deep, liquid‐containing tank, such as an overhead water tank on a building, with a vertically submerged stretched membrane (SSM). Here, instead of the sloshing mode, which can become detuned and also affords a low damper mass ratio, the impulsive liquid–membrane interacting system is designed to serve as a dynamic vibration absorber. The requirement of tuning the frequency of the impulsive liquid–membrane interacting system to the structural frequency can be achieved without any imposition on the tank dimensions, which are generally fixed from the tank's functional requirements. The system frequency would remain unchanged so long the membrane would remain submerged below a minimum liquid depth, thereby allowing fluctuation of liquid level within a prescribed range of the tank depth. The formulation for obtaining the frequency of the impulsive liquid–membrane interacting system is derived, using the sub‐domain partition approach. It is seen that through suitable adjustment of the design parameters of the membrane, the proposed tank damper can be tuned to both short‐period and to long‐period structures. Further, the impulsive liquid mass, which otherwise has no role to play in the damping mechanism of a tuned liquid damper (TLD), is here utilized to absorb and dissipate the vibrational energy. Through a time‐domain study considering recorded seismic accelerograms, the significant control effectiveness of the proposed damper system is illustrated. Further, the results obtained from the equivalent mechanical model of the structure–damper system are compared with those from a finite element analysis of the fluid–structure system in the ANSYS Workbench environment.
{"title":"Enhancing tunability of liquid storage tanks to function as deep tuned liquid dampers by use of a submerged stretched membrane","authors":"Tanmoy Konar, Anupama Das, A. Ghosh","doi":"10.1002/stc.3109","DOIUrl":"https://doi.org/10.1002/stc.3109","url":null,"abstract":"This is a study on a deep, liquid‐containing tank, such as an overhead water tank on a building, with a vertically submerged stretched membrane (SSM). Here, instead of the sloshing mode, which can become detuned and also affords a low damper mass ratio, the impulsive liquid–membrane interacting system is designed to serve as a dynamic vibration absorber. The requirement of tuning the frequency of the impulsive liquid–membrane interacting system to the structural frequency can be achieved without any imposition on the tank dimensions, which are generally fixed from the tank's functional requirements. The system frequency would remain unchanged so long the membrane would remain submerged below a minimum liquid depth, thereby allowing fluctuation of liquid level within a prescribed range of the tank depth. The formulation for obtaining the frequency of the impulsive liquid–membrane interacting system is derived, using the sub‐domain partition approach. It is seen that through suitable adjustment of the design parameters of the membrane, the proposed tank damper can be tuned to both short‐period and to long‐period structures. Further, the impulsive liquid mass, which otherwise has no role to play in the damping mechanism of a tuned liquid damper (TLD), is here utilized to absorb and dissipate the vibrational energy. Through a time‐domain study considering recorded seismic accelerograms, the significant control effectiveness of the proposed damper system is illustrated. Further, the results obtained from the equivalent mechanical model of the structure–damper system are compared with those from a finite element analysis of the fluid–structure system in the ANSYS Workbench environment.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82003621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhuodong Yang, L. Huo, Jingkai Wang, Jing Zhou, Xiaoyu Bai
{"title":"Additional Cover","authors":"Zhuodong Yang, L. Huo, Jingkai Wang, Jing Zhou, Xiaoyu Bai","doi":"10.1002/stc.3134","DOIUrl":"https://doi.org/10.1002/stc.3134","url":null,"abstract":"","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76656989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Structural physical parameters often vary gradually due to the degradation of material properties or effects of environment. In this paper, two novel approaches are proposed to identify the gradually varying physical parameters based on the discrete cosine transform (DCT) using partial measurements of structural responses. Approach I is proposed for the circumstance of known excitations. The gradually varying physical parameters are first located by the fading‐factor extended Kalman filter (FEKF) and then identified by the proposed DCT integrated with Kalman filter (KF) method. Approach II is proposed for the identification of gradually varying physical parameters under unknown excitations. The gradually varying physical parameters are first localized by the proposed fading‐factor extended Kalman filter under unknown input (FEKF‐UI) and then identified by the proposed DCT integrated with Kalman filter under unknown input (KF‐UI). Numerical examples demonstrate that the proposed approaches can identify the gradually varying physical parameters accurately with incomplete measurement data. Moreover, the identification of time‐varying cable force in cable‐stayed bridge is also discussed as a case study of the proposed approach I. Experimental verification shows that it provides a new path to identify the time‐varying cable force by only using one acceleration response measurement of the cable.
{"title":"Identification of gradually varying physical parameters based on discrete cosine transform using partial measurements","authors":"Ning Yang, Ying Lei, Jun Li, Hong Hao","doi":"10.1002/stc.3111","DOIUrl":"https://doi.org/10.1002/stc.3111","url":null,"abstract":"Structural physical parameters often vary gradually due to the degradation of material properties or effects of environment. In this paper, two novel approaches are proposed to identify the gradually varying physical parameters based on the discrete cosine transform (DCT) using partial measurements of structural responses. Approach I is proposed for the circumstance of known excitations. The gradually varying physical parameters are first located by the fading‐factor extended Kalman filter (FEKF) and then identified by the proposed DCT integrated with Kalman filter (KF) method. Approach II is proposed for the identification of gradually varying physical parameters under unknown excitations. The gradually varying physical parameters are first localized by the proposed fading‐factor extended Kalman filter under unknown input (FEKF‐UI) and then identified by the proposed DCT integrated with Kalman filter under unknown input (KF‐UI). Numerical examples demonstrate that the proposed approaches can identify the gradually varying physical parameters accurately with incomplete measurement data. Moreover, the identification of time‐varying cable force in cable‐stayed bridge is also discussed as a case study of the proposed approach I. Experimental verification shows that it provides a new path to identify the time‐varying cable force by only using one acceleration response measurement of the cable.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77881170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mitigation of bridge cable vibration has long been a research hotspot with substantial developments contributed to the field. In addition to vibration control, a recent development trend incorporates auxiliary sensors, local computing modules, and data transmission devices to establish a comprehensive, integrated cable control and health monitoring system, which requires external energy input. However, an external power supply for these devices is not considered an attractive option, considering that the kinetic energy embodied in cable vibrations can be potentially harvested to cover such power demand, leading to the establishment of an independent self‐powered control and health monitoring system. In this regard, we proposed an unprecedented solution for cable vibration mitigation by developing a novel H‐bridge‐based electromagnetic inerter damper (HB‐EMID) in this work, in which HB‐EMID can emulate the control behavior of an inerter damper and possess an energy‐harvesting function. Meanwhile, the newly proposed HB‐EMID is granted with great flexibility that can alter its equivalent mechanical properties by merely adjusting the corresponding coding. Following the introduction of the system topology and working mechanism, this study applies an HB‐EMID to a cable structure and systematically investigates the balanced control and energy‐harvesting performances, as well as its feasibility to full‐scale application. Both satisfactory control performance and sufficient harvested power are confirmed through numerical validation.
{"title":"Cable vibration mitigation by using an H‐bridge‐based electromagnetic inerter damper with energy harvesting function","authors":"Jin-Yang Li, Songye Zhu","doi":"10.1002/stc.3120","DOIUrl":"https://doi.org/10.1002/stc.3120","url":null,"abstract":"The mitigation of bridge cable vibration has long been a research hotspot with substantial developments contributed to the field. In addition to vibration control, a recent development trend incorporates auxiliary sensors, local computing modules, and data transmission devices to establish a comprehensive, integrated cable control and health monitoring system, which requires external energy input. However, an external power supply for these devices is not considered an attractive option, considering that the kinetic energy embodied in cable vibrations can be potentially harvested to cover such power demand, leading to the establishment of an independent self‐powered control and health monitoring system. In this regard, we proposed an unprecedented solution for cable vibration mitigation by developing a novel H‐bridge‐based electromagnetic inerter damper (HB‐EMID) in this work, in which HB‐EMID can emulate the control behavior of an inerter damper and possess an energy‐harvesting function. Meanwhile, the newly proposed HB‐EMID is granted with great flexibility that can alter its equivalent mechanical properties by merely adjusting the corresponding coding. Following the introduction of the system topology and working mechanism, this study applies an HB‐EMID to a cable structure and systematically investigates the balanced control and energy‐harvesting performances, as well as its feasibility to full‐scale application. Both satisfactory control performance and sufficient harvested power are confirmed through numerical validation.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74950761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For precisely disclosing the seismic performance of tuned liquid damper (TLD) vibration control structures, the shaking table substructure test (STST) method is presented and experimentally validated, and the parametric effects on the reduction efficiency of TLD are further investigated by using the STST method in this paper. Firstly, one optimal design method of TLD for high‐rise structures is presented. Secondly, the STST based on three variable control method (TVCM) for the TLD vibration control structures is presented. Thirdly, the effectiveness and robustness of the STST for TLD vibration control structures are validated by a series of tests on one three‐story‐frame structure with a rectangular TLD. Finally, the parametric effects on the reduction efficiency of TLD, in terms of mass ratio and liquid depth, are investigated using the STST method. Experimental results show that the displacement and acceleration responses of the STST match well with that of the traditional shaking table tests under El Centro (NS, 1940) and Taft earthquake wave record excitations, which indicates the effectiveness and the robustness of the STST based on TVCM for TLD vibration control structures. It is also shown from the experimental results that the best mass ratio and liquid depth are 4% and 40 mm, respectively, which are consistent with the optimal designs of TLD. Moreover, the control performance of TLD is not only related to its parameters but also related to the spectral characteristics of ground motion excitations.
为了准确揭示调谐液体阻尼器(TLD)减振结构的抗震性能，本文提出了振动台子结构试验(STST)方法并进行了实验验证，并利用STST方法进一步研究了参数对TLD减振效率的影响。首先，提出了一种高层结构TLD优化设计方法。其次，提出了基于三变量控制方法(TVCM)的TLD振动控制结构STST。第三，通过对一个矩形TLD三层框架结构的一系列试验，验证了STST对TLD振动控制结构的有效性和鲁棒性。最后，利用STST方法研究了质量比和液深等参数对TLD还原效率的影响。实验结果表明，在El Centro (NS, 1940)和Taft地震波记录激励下，STST的位移和加速度响应与传统振动台试验结果吻合较好，表明了基于TVCM的STST对TLD振动控制结构的有效性和鲁棒性。实验结果表明，最佳质量比和液深分别为4%和40 mm，与TLD的最佳设计一致。此外，TLD的控制性能不仅与其参数有关，还与地震动激励的频谱特性有关。
{"title":"Shaking table substructure test of tuned liquid damper for controlling earthquake response of structure","authors":"Guoshan Xu, Lichang Zheng, Y. Bao","doi":"10.1002/stc.3122","DOIUrl":"https://doi.org/10.1002/stc.3122","url":null,"abstract":"For precisely disclosing the seismic performance of tuned liquid damper (TLD) vibration control structures, the shaking table substructure test (STST) method is presented and experimentally validated, and the parametric effects on the reduction efficiency of TLD are further investigated by using the STST method in this paper. Firstly, one optimal design method of TLD for high‐rise structures is presented. Secondly, the STST based on three variable control method (TVCM) for the TLD vibration control structures is presented. Thirdly, the effectiveness and robustness of the STST for TLD vibration control structures are validated by a series of tests on one three‐story‐frame structure with a rectangular TLD. Finally, the parametric effects on the reduction efficiency of TLD, in terms of mass ratio and liquid depth, are investigated using the STST method. Experimental results show that the displacement and acceleration responses of the STST match well with that of the traditional shaking table tests under El Centro (NS, 1940) and Taft earthquake wave record excitations, which indicates the effectiveness and the robustness of the STST based on TVCM for TLD vibration control structures. It is also shown from the experimental results that the best mass ratio and liquid depth are 4% and 40 mm, respectively, which are consistent with the optimal designs of TLD. Moreover, the control performance of TLD is not only related to its parameters but also related to the spectral characteristics of ground motion excitations.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80118144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liang-jiu Jia, Kui-Yu Fan, P. Xiang, Guanqing Song, Zhuofeng Li
A single‐story controlled rocking‐column steel frame with self‐centering frictional connections is proposed in this paper. The frame is designed to rock when subjected to excitations beyond the frequent earthquake level. A shaking table test is conducted on a 1/3 scaled single‐story rocking‐column steel frame to investigate its dynamic responses under excitations along strong‐axis direction of the frictional connections. The structure is subjected to a sequence of excitations with increasing intensities till the maximum considered earthquake (MCE) level. The test results indicate that the proposed system can achieve a low‐damage structural design with almost zero residual drift ratio and only minor local material yielding. In addition, a design method for the proposed rocking‐column steel frame is also presented. At last, a finite element model is established by Abaqus to predict the seismic responses of the proposed structure with pretty good accuracy.
{"title":"Shaking table test on single‐story rocking‐column steel frame under excitations along strong axis","authors":"Liang-jiu Jia, Kui-Yu Fan, P. Xiang, Guanqing Song, Zhuofeng Li","doi":"10.1002/stc.3125","DOIUrl":"https://doi.org/10.1002/stc.3125","url":null,"abstract":"A single‐story controlled rocking‐column steel frame with self‐centering frictional connections is proposed in this paper. The frame is designed to rock when subjected to excitations beyond the frequent earthquake level. A shaking table test is conducted on a 1/3 scaled single‐story rocking‐column steel frame to investigate its dynamic responses under excitations along strong‐axis direction of the frictional connections. The structure is subjected to a sequence of excitations with increasing intensities till the maximum considered earthquake (MCE) level. The test results indicate that the proposed system can achieve a low‐damage structural design with almost zero residual drift ratio and only minor local material yielding. In addition, a design method for the proposed rocking‐column steel frame is also presented. At last, a finite element model is established by Abaqus to predict the seismic responses of the proposed structure with pretty good accuracy.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76252660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Ye, Si-Yuan Ma, Zhi‐Xiong Liu, Yang Ding, Zhe‐Xun Li, T. Jin
Rapid and accurate assessment of the damage to bridge structures after an earthquake can provide a basis for decision‐making regarding post‐earthquake emergency work. However, the traditional structural damage inspection techniques are subjective, time‐consuming, and inefficient. This paper proposed a framework for rapid post‐earthquake structural damage inspection and condition assessment by integrating the technologies of satellite, unmanned aerial vehicle (UAV), and smartphone with the deep learning approach. The images of structural components of post‐earthquake bridges can be obtained by UAVs and smartphones. Furthermore, the multi‐task high‐resolution net (MT‐HRNet) model was adopted to recognize the structural components and damage conditions by weighting and combining the loss functions of a single‐task HRNet model. The performance of the proposed MT‐HRNet model and the single‐task HRNet model was verified based on the Tokaido dataset, which includes 2000 images of post‐earthquake bridges. The results showed that the MT‐HRNet model and the HRNet model exhibited equivalent recognition accuracy, while the number of floating‐point‐operations (FLOPs) and the parameters of the MT‐HRNet model were reduced by 46.48% and 49.58% compared with the HRNet model. In addition, a method for the determination of the safety risk level of the post‐earthquake bridge structures was developed, and the evaluation indices were established by considering the damage type, the spalling area, and the width of cracks as well as the recognition statistics of all images in Tokaido dataset. This study will provide a valuable reference for the rapid determination of structural safety level and the corresponding treatment measures of post‐earthquake bridges.
{"title":"Post‐earthquake damage recognition and condition assessment of bridges using UAV integrated with deep learning approach","authors":"X. Ye, Si-Yuan Ma, Zhi‐Xiong Liu, Yang Ding, Zhe‐Xun Li, T. Jin","doi":"10.1002/stc.3128","DOIUrl":"https://doi.org/10.1002/stc.3128","url":null,"abstract":"Rapid and accurate assessment of the damage to bridge structures after an earthquake can provide a basis for decision‐making regarding post‐earthquake emergency work. However, the traditional structural damage inspection techniques are subjective, time‐consuming, and inefficient. This paper proposed a framework for rapid post‐earthquake structural damage inspection and condition assessment by integrating the technologies of satellite, unmanned aerial vehicle (UAV), and smartphone with the deep learning approach. The images of structural components of post‐earthquake bridges can be obtained by UAVs and smartphones. Furthermore, the multi‐task high‐resolution net (MT‐HRNet) model was adopted to recognize the structural components and damage conditions by weighting and combining the loss functions of a single‐task HRNet model. The performance of the proposed MT‐HRNet model and the single‐task HRNet model was verified based on the Tokaido dataset, which includes 2000 images of post‐earthquake bridges. The results showed that the MT‐HRNet model and the HRNet model exhibited equivalent recognition accuracy, while the number of floating‐point‐operations (FLOPs) and the parameters of the MT‐HRNet model were reduced by 46.48% and 49.58% compared with the HRNet model. In addition, a method for the determination of the safety risk level of the post‐earthquake bridge structures was developed, and the evaluation indices were established by considering the damage type, the spalling area, and the width of cracks as well as the recognition statistics of all images in Tokaido dataset. This study will provide a valuable reference for the rapid determination of structural safety level and the corresponding treatment measures of post‐earthquake bridges.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84985749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yang Deng, Hanwen Ju, Wenqiang Zhai, A. Li, You-liang Ding
Deflection is an important issue in bridge structural health monitoring. An accurate deflection–vehicle load–temperature correlation model is critical to abnormal data identification, deflection prediction under extreme conditions, and bridge structural assessment. However, because of the discrete distribution in time domain of vehicle load and the extreme complexity of the deflection–vehicle load–temperature correlation, the correlation modeling method needs further studies. A novel deflection–vehicle load–temperature correlation modeling method is developed in this study. Based on the concept of deflection influence line (DIL), the raw vehicle load monitoring data are transformed into time‐continuous vehicle influence coefficient (VIC). By using gated recurrent unit (GRU) neural network, a correlation model with inputs of VIC and environmental temperature data and output of deflection data is established. Taking a suspension bridge in China as an example, the prediction accuracy of short‐, medium‐, and long‐term correlation models is tested. Moreover, based on the correlation model, a decomposition method of temperature‐ and vehicle‐induced deflection components is proposed. The results show that the predicted deflection of the short‐term correlation model is basically consistent with the real‐time monitoring data, while the medium‐ and long‐term correlation models have accurate prediction ability for the deflection extreme values in a certain time window. The temperature‐ and vehicle‐induced deflection components separated by using the correlation model are in good agreement with the wavelet decomposition (WD) results, with clear physical meaning and independent of empirical judgment.
{"title":"Correlation model of deflection, vehicle load, and temperature for in‐service bridge using deep learning and structural health monitoring","authors":"Yang Deng, Hanwen Ju, Wenqiang Zhai, A. Li, You-liang Ding","doi":"10.1002/stc.3113","DOIUrl":"https://doi.org/10.1002/stc.3113","url":null,"abstract":"Deflection is an important issue in bridge structural health monitoring. An accurate deflection–vehicle load–temperature correlation model is critical to abnormal data identification, deflection prediction under extreme conditions, and bridge structural assessment. However, because of the discrete distribution in time domain of vehicle load and the extreme complexity of the deflection–vehicle load–temperature correlation, the correlation modeling method needs further studies. A novel deflection–vehicle load–temperature correlation modeling method is developed in this study. Based on the concept of deflection influence line (DIL), the raw vehicle load monitoring data are transformed into time‐continuous vehicle influence coefficient (VIC). By using gated recurrent unit (GRU) neural network, a correlation model with inputs of VIC and environmental temperature data and output of deflection data is established. Taking a suspension bridge in China as an example, the prediction accuracy of short‐, medium‐, and long‐term correlation models is tested. Moreover, based on the correlation model, a decomposition method of temperature‐ and vehicle‐induced deflection components is proposed. The results show that the predicted deflection of the short‐term correlation model is basically consistent with the real‐time monitoring data, while the medium‐ and long‐term correlation models have accurate prediction ability for the deflection extreme values in a certain time window. The temperature‐ and vehicle‐induced deflection components separated by using the correlation model are in good agreement with the wavelet decomposition (WD) results, with clear physical meaning and independent of empirical judgment.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87253859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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