Pub Date : 2024-05-07DOI: 10.1177/13694332241252270
Linren Zhou, Ruitian Wanyan, Shaoji Li
The heat exchange between bridges and external environments is the primary cause of the temperature effect on bridges. The complexity of the two-phase (gas–solid) heat transfer mechanism, the diversity of the surface characteristics of bridge materials, and the uncertainties of the environment in which bridges are located make the numerical calculation of the heat exchange between bridges and external environments difficult. Several studies have been conducted by scholars around the world. In this work, the research on convective and radiative heat exchange between bridges and external environments is surveyed, analyzed, and summarized. The influencing factors and calculation methods of bridge temperature are examined, and the convective heat transfer and radiation mechanisms, theoretical calculations, and experimental measurement methods used to investigate the relation between bridges and external environments are summarized and analyzed. The value determination methods for convective heat transfer and radiation absorption coefficients in the calculation of the bridge temperature field are summarized. In addition, the problems and shortcomings of current research are evaluated, and future research directions are identified and discussed.
{"title":"Review on convective and radiation heat transfer between bridges and external environments","authors":"Linren Zhou, Ruitian Wanyan, Shaoji Li","doi":"10.1177/13694332241252270","DOIUrl":"https://doi.org/10.1177/13694332241252270","url":null,"abstract":"The heat exchange between bridges and external environments is the primary cause of the temperature effect on bridges. The complexity of the two-phase (gas–solid) heat transfer mechanism, the diversity of the surface characteristics of bridge materials, and the uncertainties of the environment in which bridges are located make the numerical calculation of the heat exchange between bridges and external environments difficult. Several studies have been conducted by scholars around the world. In this work, the research on convective and radiative heat exchange between bridges and external environments is surveyed, analyzed, and summarized. The influencing factors and calculation methods of bridge temperature are examined, and the convective heat transfer and radiation mechanisms, theoretical calculations, and experimental measurement methods used to investigate the relation between bridges and external environments are summarized and analyzed. The value determination methods for convective heat transfer and radiation absorption coefficients in the calculation of the bridge temperature field are summarized. In addition, the problems and shortcomings of current research are evaluated, and future research directions are identified and discussed.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140930558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-06DOI: 10.1177/13694332241252281
Bo Hu, Hai-Bo Wang
Concrete-filled steel tubular (CFST) columns have been widely used in multi-story and high-rise frame structures. During the service period, they may suffer vehicle impact due to traffic accidents or terrorist attacks. This paper numerically evaluates the performance of CFST columns under vehicle impact and investigates the effects of carbon FRP (CFRP) wrapping arrangements on performance improvement of the columns. Before that, a numerical model was developed to simulate the responses of CFST columns without and with FRP wrapping under vehicle impact and post-impact axial compression, and then calibrated by reported tests. Evaluation results show that the performance of CSFT columns under vehicle impact is divided into five levels, i.e., no repair required, rapid repair required, minor repair needed, major repair needed, and replacement needed. The performance level decreases with the increase in the vehicle weight or speed and increases with the increase in the column diameter or steel tube thickness. The column height has little effects on the performance level. A higher axial load ratio, e.g., 0.5, might reduce the performance level. Besides, a CFST column tends to fail in flexure mode when hit by F800 medium truck, while it may fail in flexure & shear mode when hit by C2500 pickup truck. Investigation results indicate that FRP wrapping with each layer orientation of 90° (i.e., in the longitudinal direction) and 0° (i.e., in the hoop direction) present the best performance improvement for a CFST column possibly undergoing flexure & shear and flexure failure, respectively. The increase of the number of FRP layers effectively improves the performance levels of CFST columns but the excessive demand may be not economical. It is not necessary to employ an FRP wrapping range of 100% for improving the vehicular impact performance level of a CFST column to the expected one.
{"title":"Performance evaluation and FRP strengthening of concrete-filled steel tubular columns subjected to vehicle impact","authors":"Bo Hu, Hai-Bo Wang","doi":"10.1177/13694332241252281","DOIUrl":"https://doi.org/10.1177/13694332241252281","url":null,"abstract":"Concrete-filled steel tubular (CFST) columns have been widely used in multi-story and high-rise frame structures. During the service period, they may suffer vehicle impact due to traffic accidents or terrorist attacks. This paper numerically evaluates the performance of CFST columns under vehicle impact and investigates the effects of carbon FRP (CFRP) wrapping arrangements on performance improvement of the columns. Before that, a numerical model was developed to simulate the responses of CFST columns without and with FRP wrapping under vehicle impact and post-impact axial compression, and then calibrated by reported tests. Evaluation results show that the performance of CSFT columns under vehicle impact is divided into five levels, i.e., no repair required, rapid repair required, minor repair needed, major repair needed, and replacement needed. The performance level decreases with the increase in the vehicle weight or speed and increases with the increase in the column diameter or steel tube thickness. The column height has little effects on the performance level. A higher axial load ratio, e.g., 0.5, might reduce the performance level. Besides, a CFST column tends to fail in flexure mode when hit by F800 medium truck, while it may fail in flexure & shear mode when hit by C2500 pickup truck. Investigation results indicate that FRP wrapping with each layer orientation of 90° (i.e., in the longitudinal direction) and 0° (i.e., in the hoop direction) present the best performance improvement for a CFST column possibly undergoing flexure & shear and flexure failure, respectively. The increase of the number of FRP layers effectively improves the performance levels of CFST columns but the excessive demand may be not economical. It is not necessary to employ an FRP wrapping range of 100% for improving the vehicular impact performance level of a CFST column to the expected one.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140888558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-06DOI: 10.1177/13694332241252275
Jincan Huang, Wei Hou, Zhiqiang Li, Yang Liu, Yixin Zhang
This study aims to investigate the influence of different surface treatments, including smooth interface, rough interface, anchor bolt connection, and epoxy bonding agent, on the shear resistance of Engineered Cementitious Composites (ECC)-concrete interface through bi-surface shear testing. The experimental results show that the interfacial shear strength between ECC and concrete is significantly enhanced by the implementation of the three interface treatment methods, as opposed to the smooth interface. Among these methods, the anchor bolt connection exhibits the greatest improvement in interfacial bonding performance. Notably, cohesive failure is observed in the anchor bolt connection method, while the other three methods result in adhesive failure, with only the anchor bolt connection method displaying ductile failure behavior. Following a comprehensive review of relevant studies and the outcomes of this experiment, three distinct interface bonding mechanisms were identified and the forces contributing to the bond were analyzed. Results indicated that the interfacial bond strength is notably influenced by the surface roughness. These research findings substantiate the viability of utilizing the anchor bolt connection method, particularly in applications where ductility requirements in the repair layer are essential for structural integrity.
{"title":"Enhancing the interfacial bond performance of engineered cementitious composites and concrete","authors":"Jincan Huang, Wei Hou, Zhiqiang Li, Yang Liu, Yixin Zhang","doi":"10.1177/13694332241252275","DOIUrl":"https://doi.org/10.1177/13694332241252275","url":null,"abstract":"This study aims to investigate the influence of different surface treatments, including smooth interface, rough interface, anchor bolt connection, and epoxy bonding agent, on the shear resistance of Engineered Cementitious Composites (ECC)-concrete interface through bi-surface shear testing. The experimental results show that the interfacial shear strength between ECC and concrete is significantly enhanced by the implementation of the three interface treatment methods, as opposed to the smooth interface. Among these methods, the anchor bolt connection exhibits the greatest improvement in interfacial bonding performance. Notably, cohesive failure is observed in the anchor bolt connection method, while the other three methods result in adhesive failure, with only the anchor bolt connection method displaying ductile failure behavior. Following a comprehensive review of relevant studies and the outcomes of this experiment, three distinct interface bonding mechanisms were identified and the forces contributing to the bond were analyzed. Results indicated that the interfacial bond strength is notably influenced by the surface roughness. These research findings substantiate the viability of utilizing the anchor bolt connection method, particularly in applications where ductility requirements in the repair layer are essential for structural integrity.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140888973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-27DOI: 10.1177/13694332241252274
Qiwu Wang, Fei Peng, Zhi Fang
The use of ultra-high-performance concrete (UHPC) allows for much smaller cross-sections compared to conventional reinforced concrete columns, which may make reinforced UHPC (R-UHPC) columns more susceptible to slenderness effects. Currently, there is no guideline in design standards for the slenderness limit of R-UHPC columns. This paper, therefore, attempts to develop a design provision for determining the slenderness limit of R-UHPC columns. Firstly, a numerical analytical model was proposed for predicting the load-deflection of R-UHPC columns under eccentric loading, which was validated by comparing its predictions with available experimental results from the available literature. Based on the validated model, a parametric study was then conducted to determine the key parameters affecting the slenderness limit of R-UHPC columns. It was found that the slenderness limit corresponding to the 5% strength reduction was sensitive to the ultimate compressive strain of UHPC, the tensile strength of UHPC, and the reinforcement ratio. On this basis, a design equation for the slenderness limit of R-UHPC columns in single curvature was statistically derived. Additionally, the slenderness limit for R-UHPC columns in non-sway frames was also proposed in a convenient form for design procedures.
{"title":"Slenderness limit for reinforced ultra-high-performance concrete columns","authors":"Qiwu Wang, Fei Peng, Zhi Fang","doi":"10.1177/13694332241252274","DOIUrl":"https://doi.org/10.1177/13694332241252274","url":null,"abstract":"The use of ultra-high-performance concrete (UHPC) allows for much smaller cross-sections compared to conventional reinforced concrete columns, which may make reinforced UHPC (R-UHPC) columns more susceptible to slenderness effects. Currently, there is no guideline in design standards for the slenderness limit of R-UHPC columns. This paper, therefore, attempts to develop a design provision for determining the slenderness limit of R-UHPC columns. Firstly, a numerical analytical model was proposed for predicting the load-deflection of R-UHPC columns under eccentric loading, which was validated by comparing its predictions with available experimental results from the available literature. Based on the validated model, a parametric study was then conducted to determine the key parameters affecting the slenderness limit of R-UHPC columns. It was found that the slenderness limit corresponding to the 5% strength reduction was sensitive to the ultimate compressive strain of UHPC, the tensile strength of UHPC, and the reinforcement ratio. On this basis, a design equation for the slenderness limit of R-UHPC columns in single curvature was statistically derived. Additionally, the slenderness limit for R-UHPC columns in non-sway frames was also proposed in a convenient form for design procedures.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140810229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Floating production storage and offloading systems (FPSOs) are gaining prominence in the offshore industry. FPSOs are generally designed to weathervane, necessitating surge vibration control for station keeping. Since the natural period of surge vibration is far higher than the dominant period of the input wave load, instead of supplemental damping, a high inertial device, such as the tuned mass damper inerter (TMDI), would be effective. This concept has hitherto not been investigated for the FPSO. A frequency domain formulation of the FPSO-TMDI system under wave force, considering interaction of the liquid cargo is presented. Utilizing Froude-Krylov theory, suitably modified to account for diffraction effects, wave force on the FPSO is obtained using field data from North Sea. TMDI parameters are optimized using Genetic Algorithm under different tank-fill conditions. The results demonstrate that the TMDI holds potential in providing an effective and robust performance in controlling the surge motion of FPSOs.
{"title":"Wave-induced vibration control of Floating production storage and offloading systems by tuned mass damper inerter","authors":"Nilarghya Sarkar, Sanjukta Chakraborty, Aparna (Dey) Ghosh","doi":"10.1177/13694332241247919","DOIUrl":"https://doi.org/10.1177/13694332241247919","url":null,"abstract":"Floating production storage and offloading systems (FPSOs) are gaining prominence in the offshore industry. FPSOs are generally designed to weathervane, necessitating surge vibration control for station keeping. Since the natural period of surge vibration is far higher than the dominant period of the input wave load, instead of supplemental damping, a high inertial device, such as the tuned mass damper inerter (TMDI), would be effective. This concept has hitherto not been investigated for the FPSO. A frequency domain formulation of the FPSO-TMDI system under wave force, considering interaction of the liquid cargo is presented. Utilizing Froude-Krylov theory, suitably modified to account for diffraction effects, wave force on the FPSO is obtained using field data from North Sea. TMDI parameters are optimized using Genetic Algorithm under different tank-fill conditions. The results demonstrate that the TMDI holds potential in providing an effective and robust performance in controlling the surge motion of FPSOs.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140629355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1177/13694332241247917
Dong-Hui Yang, Yong-Chang Zhang, Xu Zheng, Ting-Hua Yi, Hong-Nan Li
Bearings are regarded as a crucial element that impacts the overall performance of the seismic analysis of bridges. The assessment of seismic performance in bridges heavily depends on the nonlinear features of bridge bearings. Therefore, it is essential to simulate the nonlinear mechanical behavior of bridge bearings to attain the required accuracy of seismic analysis. This paper examines the friction features of pot bearings using the Bouc-Wen hysteretic model, based on which a nonlinear model of pot bearings is proposed. The proposed model can rapidly and effectively analyze the nonlinear mechanical behaviors of bridge bearings under horizontal earthquakes by adequately simplifying the mechanical properties of these bearings. The accuracy of the model for horizontal seismic effects analysis is validated using a numerical simulation method. The simulation compares the nonlinear model seismic effects of the bearing with a linear-elastic model that ignores the bearing frictional effects under horizontal seismic action. The results demonstrated that in the proposed nonlinear model, the ratio of the composite bending moment and yield bending moment of the pier bottom section (demand capacity ratio) is lower than that of the linear elastic model, leading to a more accurate analysis of horizontal seismic effects and thus preventing overestimation of seismic consequences.
{"title":"Nonlinear model of bridge bearings considering friction effect under horizontal seismic action","authors":"Dong-Hui Yang, Yong-Chang Zhang, Xu Zheng, Ting-Hua Yi, Hong-Nan Li","doi":"10.1177/13694332241247917","DOIUrl":"https://doi.org/10.1177/13694332241247917","url":null,"abstract":"Bearings are regarded as a crucial element that impacts the overall performance of the seismic analysis of bridges. The assessment of seismic performance in bridges heavily depends on the nonlinear features of bridge bearings. Therefore, it is essential to simulate the nonlinear mechanical behavior of bridge bearings to attain the required accuracy of seismic analysis. This paper examines the friction features of pot bearings using the Bouc-Wen hysteretic model, based on which a nonlinear model of pot bearings is proposed. The proposed model can rapidly and effectively analyze the nonlinear mechanical behaviors of bridge bearings under horizontal earthquakes by adequately simplifying the mechanical properties of these bearings. The accuracy of the model for horizontal seismic effects analysis is validated using a numerical simulation method. The simulation compares the nonlinear model seismic effects of the bearing with a linear-elastic model that ignores the bearing frictional effects under horizontal seismic action. The results demonstrated that in the proposed nonlinear model, the ratio of the composite bending moment and yield bending moment of the pier bottom section (demand capacity ratio) is lower than that of the linear elastic model, leading to a more accurate analysis of horizontal seismic effects and thus preventing overestimation of seismic consequences.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140614906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1177/13694332241247918
Linren Zhou, Taojun Wang, Yumeng Chen
Temperature is an important load factor affecting the structural performances of bridges. The rapid acquisition of bridge temperature data is significant for bridge temperature effect analysis and assessment. On the bases of ground meteorological shared big data, a bridge temperature prediction method based on long short-term memory (LSTM) neural network is proposed. The proposed method is used to investigate the key issues of data preprocessing, model input feature selection, time-length determination, and hyper-parameter preference. Moreover, the proposed method relies on the maximum information coefficient to quantify the strongly correlated features and uses a two-layer deep LSTM neural network to improve the model’s time series information utilization and prediction capability. The constructed neural grid model is experimentally studied and verified based on the long-term measured data of the scaled bridge model in an outdoor environment. Comparative assessment with other typical time series models, such as NARX, RNN, and GRU, demonstrate that the LSTM neural network model exhibits the best generalization ability and highest temperature prediction accuracy, with a maximum absolute error of approximately 2°C and relative error below 5%. The engineering applicability and effectiveness of LSTM for bridge temperature prediction are verified.
{"title":"Bridge temperature prediction method based on long short-term memory neural networks and shared meteorological data","authors":"Linren Zhou, Taojun Wang, Yumeng Chen","doi":"10.1177/13694332241247918","DOIUrl":"https://doi.org/10.1177/13694332241247918","url":null,"abstract":"Temperature is an important load factor affecting the structural performances of bridges. The rapid acquisition of bridge temperature data is significant for bridge temperature effect analysis and assessment. On the bases of ground meteorological shared big data, a bridge temperature prediction method based on long short-term memory (LSTM) neural network is proposed. The proposed method is used to investigate the key issues of data preprocessing, model input feature selection, time-length determination, and hyper-parameter preference. Moreover, the proposed method relies on the maximum information coefficient to quantify the strongly correlated features and uses a two-layer deep LSTM neural network to improve the model’s time series information utilization and prediction capability. The constructed neural grid model is experimentally studied and verified based on the long-term measured data of the scaled bridge model in an outdoor environment. Comparative assessment with other typical time series models, such as NARX, RNN, and GRU, demonstrate that the LSTM neural network model exhibits the best generalization ability and highest temperature prediction accuracy, with a maximum absolute error of approximately 2°C and relative error below 5%. The engineering applicability and effectiveness of LSTM for bridge temperature prediction are verified.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140614905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-16DOI: 10.1177/13694332241247921
Xiumeng Bu, Lidong Wang, Yan Han, Hanyun Liu, Peng Hu, CS Cai
To improve the anti-interference ability of maglev trains, a dynamic model of the high-speed maglev train with a nonlinear suspension controller for the guideway system is proposed in this paper. Based on the nonlinear characteristics of the magnetic suspension system, a nonlinear decoupling controller is designed using the feedback linearization theory. Then, a high-speed maglev train model is refined with a guideway coupling system, consisting of a maglev train simulated as a multi-body dynamics model with 537 degrees of freedom and a spatial finite element model of the guideway. Taking the Shanghai high-speed maglev train as an example, the correctness of the computational model is verified by comparing the modeling results with field measurement data, and the control effectiveness of the nonlinear controllers and the traditional PD controllers is compared considering different train speeds and disturbance forces. The results show that the suspension gap under the decoupling control is smaller than that under the PD control during the train operations. Under the same disturbance force, the decoupling control exhibits better control performance than the PD control. The variation amplitudes of the magnetic pole gaps are generally linearly related to the disturbance force.
{"title":"Dynamic model of high-speed maglev train-guideway bridge system with a nonlinear suspension controller","authors":"Xiumeng Bu, Lidong Wang, Yan Han, Hanyun Liu, Peng Hu, CS Cai","doi":"10.1177/13694332241247921","DOIUrl":"https://doi.org/10.1177/13694332241247921","url":null,"abstract":"To improve the anti-interference ability of maglev trains, a dynamic model of the high-speed maglev train with a nonlinear suspension controller for the guideway system is proposed in this paper. Based on the nonlinear characteristics of the magnetic suspension system, a nonlinear decoupling controller is designed using the feedback linearization theory. Then, a high-speed maglev train model is refined with a guideway coupling system, consisting of a maglev train simulated as a multi-body dynamics model with 537 degrees of freedom and a spatial finite element model of the guideway. Taking the Shanghai high-speed maglev train as an example, the correctness of the computational model is verified by comparing the modeling results with field measurement data, and the control effectiveness of the nonlinear controllers and the traditional PD controllers is compared considering different train speeds and disturbance forces. The results show that the suspension gap under the decoupling control is smaller than that under the PD control during the train operations. Under the same disturbance force, the decoupling control exhibits better control performance than the PD control. The variation amplitudes of the magnetic pole gaps are generally linearly related to the disturbance force.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140614750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-15DOI: 10.1177/13694332241247923
Junxiang Li, Xiwei Guo, Xinxin Zhang, Zijun Wu
It remains a significant challenge to quantitatively describe the corrosion of reinforced concrete (RC) structures under chloride penetration. Moreover, when considering uncertainties throughout the life cycle of corroded RC structures for assessing their safety, reliability, and optimal design, the complexity of the problem intensifies. To address these issues, this paper studies the time-dependent reliability analysis and optimal design of corroded RC beams. At first, the time-dependent reliability of beams is investigated by considering both the serviceability limit state (SLS), which corresponds to the corrosion initiation of the reinforced steel, and the ultimate limit state (ULS), associated with the bending failure of the beam. This analysis takes into account the time-dependent chloride diffusion coefficient and incorporates a stochastic process. The reliability is evaluated using the Monte Carlo Simulation (MCS) method and the cumulative distribution function (CDF) method. Subsequently, a time-dependent reliability-based design optimization (TRBDO) problem is formulated, and the PSO-MCS, a methodology incorporating a particle swarm optimization (PSO) algorithm and MCS is adopted to solve it. After optimization, the initial cost of the specific RC beam is reduced from 1351.879€ to 1247.075€, while the time-dependent reliability within [0, 100] years is improved from 0.6057 to 0.6508. The effectiveness of the CDF, MCS and PSO-MCS methods are demonstrated through reliability analysis and design examples of corroded RC beams.
{"title":"Time-dependent reliability assessment and optimal design of corroded reinforced concrete beams","authors":"Junxiang Li, Xiwei Guo, Xinxin Zhang, Zijun Wu","doi":"10.1177/13694332241247923","DOIUrl":"https://doi.org/10.1177/13694332241247923","url":null,"abstract":"It remains a significant challenge to quantitatively describe the corrosion of reinforced concrete (RC) structures under chloride penetration. Moreover, when considering uncertainties throughout the life cycle of corroded RC structures for assessing their safety, reliability, and optimal design, the complexity of the problem intensifies. To address these issues, this paper studies the time-dependent reliability analysis and optimal design of corroded RC beams. At first, the time-dependent reliability of beams is investigated by considering both the serviceability limit state (SLS), which corresponds to the corrosion initiation of the reinforced steel, and the ultimate limit state (ULS), associated with the bending failure of the beam. This analysis takes into account the time-dependent chloride diffusion coefficient and incorporates a stochastic process. The reliability is evaluated using the Monte Carlo Simulation (MCS) method and the cumulative distribution function (CDF) method. Subsequently, a time-dependent reliability-based design optimization (TRBDO) problem is formulated, and the PSO-MCS, a methodology incorporating a particle swarm optimization (PSO) algorithm and MCS is adopted to solve it. After optimization, the initial cost of the specific RC beam is reduced from 1351.879€ to 1247.075€, while the time-dependent reliability within [0, 100] years is improved from 0.6057 to 0.6508. The effectiveness of the CDF, MCS and PSO-MCS methods are demonstrated through reliability analysis and design examples of corroded RC beams.","PeriodicalId":50849,"journal":{"name":"Advances in Structural Engineering","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140563938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stratospheric airships require a lightweight envelope to contain lighter-than-air buoyancy gas, making the lightweight design and pressure-bearing performance of the envelope structure a key research issue. The stress state at different cross-sectional positions of the airship envelope structure is different, resulting in a low utilization rate of the overall material performance of the envelope structure. This paper proposes a design scheme for reinforcing envelope structures with sliding reinforcing cable to improve the bearing capacity of the composite fabric structure while reducing its weight, ultimately achieving the optimal strength-to-weight ratio. Two types of composite fabric structures (A-airship and B-airship) were subjected to inflatable burst tests, and the strain changes in the envelope gores were analyzed by digital image correlation. Through re-assembly of the broken composite fabric pieces and analysis of their tear textures, crack origination positions, failure causes, and the stress behavior and state at the failure position were identified. An envelope structural model with consideration of the cutting pattern effect was established, allowing the stress distribution of the envelope to be analyzed and the damage positions to be more accurately predicted. Based on the analysis of the ultimate pressure-bearing performance of an airship envelope structure, a novel idea of incorporating coupled tensile-shear stress into the strength criterion was proposed. Through the data in the study and existing references, it is verified that the strength criterion can accurately predict the ultimate pressure-bearing performance of the envelope structure.
平流层飞艇需要轻质围护结构来容纳轻于空气的浮力气体，因此围护结构的轻质设计和承压性能成为研究的重点。飞艇围护结构不同截面位置的应力状态不同，导致围护结构整体材料性能利用率低。本文提出了一种用滑动加强索加强围护结构的设计方案，在减轻重量的同时提高复合织物结构的承载能力，最终达到最佳的强度重量比。对两种复合织物结构（A 型艇和 B 型艇）进行了充气爆破试验，并通过数字图像相关分析了包络孔的应变变化。通过重新组装断裂的复合织物碎片并分析其撕裂纹理，确定了裂纹的起源位置、破坏原因以及破坏位置的应力行为和状态。建立了考虑了切割模式效应的包络结构模型，从而可以分析包络的应力分布，更准确地预测破坏位置。在分析飞艇围护结构极限承压性能的基础上，提出了将拉剪应力耦合纳入强度准则的新思路。通过研究数据和现有参考文献，验证了强度准则可以准确预测围护结构的极限承压性能。
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