Pub Date : 2024-11-13DOI: 10.1016/j.jcsr.2024.109138
Chenggang Wang , Lei Teng , Lihua Chen , Yantao Xue , Feiyu Xing
To improve the seismic performance and shear capacity of joints between steel beams and reinforced concrete columns (RCSs), this paper proposes prefabricated concrete column-steel beam joints connected by tie bars. Five joint members were designed and fabricated for the proposed static tests, and the damage pattern, hysteresis performance, and load-carrying capacity of each specimen were investigated, with the diameter of the tensile reinforcement and the relative position of the tensile reinforcement and the flange of the steel beam as the main parameters. The test results show that the hysteresis curve shape of each specimen is fuller, the ductility coefficient is between 3.30 and 4.62, and the joints have a good capacity for plastic deformation. The bearing capacity of the joints increased as the diameter of the tie bars increased; the bearing capacity and elasticity of the joints decreased when the tie bars were arranged inside the steel beam flange. In this paper, three existing shear capacity calculation methods for RCS joints are compared and evaluated, and combined with the experimental results, a finite element calculation model for this kind of joint specimen is established and a shear capacity calculation formula for prefabricated concrete column-tension reinforcement connection joints is proposed. The new calculation method agrees with the test values and can be used to design tension reinforcement connection joints for practical engineering applications.
{"title":"Shear capacity analysis of prefabricated concrete column-steel beam joints connected by tie-bars","authors":"Chenggang Wang , Lei Teng , Lihua Chen , Yantao Xue , Feiyu Xing","doi":"10.1016/j.jcsr.2024.109138","DOIUrl":"10.1016/j.jcsr.2024.109138","url":null,"abstract":"<div><div>To improve the seismic performance and shear capacity of joints between steel beams and reinforced concrete columns (RCSs), this paper proposes prefabricated concrete column-steel beam joints connected by tie bars. Five joint members were designed and fabricated for the proposed static tests, and the damage pattern, hysteresis performance, and load-carrying capacity of each specimen were investigated, with the diameter of the tensile reinforcement and the relative position of the tensile reinforcement and the flange of the steel beam as the main parameters. The test results show that the hysteresis curve shape of each specimen is fuller, the ductility coefficient is between 3.30 and 4.62, and the joints have a good capacity for plastic deformation. The bearing capacity of the joints increased as the diameter of the tie bars increased; the bearing capacity and elasticity of the joints decreased when the tie bars were arranged inside the steel beam flange. In this paper, three existing shear capacity calculation methods for RCS joints are compared and evaluated, and combined with the experimental results, a finite element calculation model for this kind of joint specimen is established and a shear capacity calculation formula for prefabricated concrete column-tension reinforcement connection joints is proposed. The new calculation method agrees with the test values and can be used to design tension reinforcement connection joints for practical engineering applications.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109138"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-13DOI: 10.1016/j.jcsr.2024.109144
Kang He , Yu Chen , Hongrui Lai , Xinghuo Wu
Stainless steel is increasingly used in renewable energy sectors due to its advantageous mechanical properties, corrosion resistance, and aesthetic appeal. However, exposure to high temperatures can significantly alter these properties, potentially compromising long-term performance in renewable energy infrastructure. This study investigates the effects of ISO 834 standard fire on the constitutive behavior of austenitic 304 stainless steel through experimental analysis. The findings indicate that cross-sectional weakening has a minimal impact on the post-fire degradation of stainless steel structures. After sufficient cooling, the elastic modulus and strain hardening index of fire-exposed stainless steel are restored to pre-fire levels. However, both the nominal yield strength and ultimate strength are significantly diminished after fire exposure, with these reductions being positively correlated with heating duration. Practical formulas are provided for predicting the nominal yield strength, ultimate strength, and ultimate strain of stainless steel after ISO 834 standard fire. Additionally, a stress-strain constitutive model has been developed that accurately predicts the full strain range observed in post-fire tensile tests of austenitic 304 stainless steel.
不锈钢具有良好的机械性能、耐腐蚀性和美观性，因此越来越多地应用于可再生能源领域。然而，暴露在高温下会显著改变这些特性，从而可能影响可再生能源基础设施的长期性能。本研究通过实验分析研究了 ISO 834 标准火灾对奥氏体 304 不锈钢构成行为的影响。研究结果表明，截面削弱对不锈钢结构火灾后降解的影响微乎其微。经过充分冷却后，受火灾影响的不锈钢的弹性模量和应变硬化指数可恢复到火灾前的水平。然而，名义屈服强度和极限强度在火灾暴露后会显著降低，这些降低与加热持续时间呈正相关。本文提供了实用的公式，用于预测不锈钢在 ISO 834 标准火灾后的名义屈服强度、极限强度和极限应变。此外，还开发了一种应力-应变构成模型，可准确预测奥氏体 304 不锈钢在火灾后拉伸试验中观察到的全部应变范围。
{"title":"Mechanical response and constitutive model of austenitic 304 stainless steel after exposure ISO 834 fire","authors":"Kang He , Yu Chen , Hongrui Lai , Xinghuo Wu","doi":"10.1016/j.jcsr.2024.109144","DOIUrl":"10.1016/j.jcsr.2024.109144","url":null,"abstract":"<div><div>Stainless steel is increasingly used in renewable energy sectors due to its advantageous mechanical properties, corrosion resistance, and aesthetic appeal. However, exposure to high temperatures can significantly alter these properties, potentially compromising long-term performance in renewable energy infrastructure. This study investigates the effects of ISO 834 standard fire on the constitutive behavior of austenitic 304 stainless steel through experimental analysis. The findings indicate that cross-sectional weakening has a minimal impact on the post-fire degradation of stainless steel structures. After sufficient cooling, the elastic modulus and strain hardening index of fire-exposed stainless steel are restored to pre-fire levels. However, both the nominal yield strength and ultimate strength are significantly diminished after fire exposure, with these reductions being positively correlated with heating duration. Practical formulas are provided for predicting the nominal yield strength, ultimate strength, and ultimate strain of stainless steel after ISO 834 standard fire. Additionally, a stress-strain constitutive model has been developed that accurately predicts the full strain range observed in post-fire tensile tests of austenitic 304 stainless steel.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109144"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The speed of assembly and structural reliability of prefabricated prefinished volumetric constructions (PPVCs) are closely dependant on the interconnections linking modules. Among these interconnections, those with frictional mechanisms can offer greater efficiency in modular construction. This paper investigates the structural performance of a novel frictional interconnection through experimental and numerical studies. Initially, A joint composed of innovative interconnection and common intra-connection (beam-to-column connection) was prefabricated and tested under cyclic loading. The numerical models of the experimental sample are developed using ABAQUS software, subsequently validated against experimental results. Then, the impact of different support conditions (pin or roller) on joint behaviour is investigated. The outcomes indicates that the joint can effectively be used in moment-resisting frames in PPVCs as a result of its adequate stiffness, being classified as a rigid connection based on AISC 316–22. The interconnection reaches its maximum load capacity through rod yielding, while the other components remained intact. Numerical simulations reveal that no sliding occurs between the endplates during the test, indicating the adequacy of axial loads. Furthermore, changing the support conditions can affect the response of the joint, governed by the beam's and the interconnection's moment capacity.
{"title":"Rocking interconnection for moment resisting modular buildings: Experimental and numerical investigation","authors":"Babak Atashfaraz , Pejman Sharafi , Parisa Shadan , Alireza Goudarzi","doi":"10.1016/j.jcsr.2024.109139","DOIUrl":"10.1016/j.jcsr.2024.109139","url":null,"abstract":"<div><div>The speed of assembly and structural reliability of prefabricated prefinished volumetric constructions (PPVCs) are closely dependant on the interconnections linking modules. Among these interconnections, those with frictional mechanisms can offer greater efficiency in modular construction. This paper investigates the structural performance of a novel frictional interconnection through experimental and numerical studies. Initially, A joint composed of innovative interconnection and common intra-connection (beam-to-column connection) was prefabricated and tested under cyclic loading. The numerical models of the experimental sample are developed using ABAQUS software, subsequently validated against experimental results. Then, the impact of different support conditions (pin or roller) on joint behaviour is investigated. The outcomes indicates that the joint can effectively be used in moment-resisting frames in PPVCs as a result of its adequate stiffness, being classified as a rigid connection based on AISC 316–22. The interconnection reaches its maximum load capacity through rod yielding, while the other components remained intact. Numerical simulations reveal that no sliding occurs between the endplates during the test, indicating the adequacy of axial loads. Furthermore, changing the support conditions can affect the response of the joint, governed by the beam's and the interconnection's moment capacity.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109139"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.jcsr.2024.109156
Chengquan Wang , Huihui Li , Liang Xu , Kaixin Xu , Licai Zhao , Qian Chen
This study proposed a novel external replaceable energy-dissipating device (EREDD) to enhance the seismic performance of prefabricated segmental concrete filled steel tubular bridge piers (PS-CFST bridge piers), while maintaining the construction efficiency of conventional segmentally assembled prefabricated piers with dry joints. The effectiveness and applicability of EREDDs in improving the seismic performance of PS-CFST bridge piers were studied through the cyclic tests. The inelastic cyclic response of PS-CFST bridge pier specimens with different arrangements of EREDDs was experimentally examined. A detailed account of the test results was provided and discussed, including the stiffness and strength characteristics, strain distributions, residual displacements, failure patterns, as well as hysteretic response and energy dissipation capability. Particular attention was also given within the experimental assessment to investigating the effects of the inter-segmental joint opening positions for the different EREDD arrangements on the seismic response of PS-CFST bridge piers. Based on the experimental findings, an analytical approach was developed for determining the hysteretic response of the proposed PS-CFST bridge piers incorporating EREDDs, offering the basis for their design and assessment in practice. Finally, the results indicate that EREDDs could effectively improve the seismic performance of PS-CFST bridge piers and the hysteretic response could be accurately predicted by using the proposed analytical approach. In addition, EREDDs allow the damage of PS-CFST bridge piers to be concentrated within the easily replaceable component, and thereby facilitating the controlled damage. This study provides an effective method for the seismic design of PS-CFST bridge piers incorporating EREDDs.
{"title":"Seismic performance of PS-CFST bridge piers with novel external replaceable energy dissipating devices","authors":"Chengquan Wang , Huihui Li , Liang Xu , Kaixin Xu , Licai Zhao , Qian Chen","doi":"10.1016/j.jcsr.2024.109156","DOIUrl":"10.1016/j.jcsr.2024.109156","url":null,"abstract":"<div><div>This study proposed a novel external replaceable energy-dissipating device (EREDD) to enhance the seismic performance of prefabricated segmental concrete filled steel tubular bridge piers (PS-CFST bridge piers), while maintaining the construction efficiency of conventional segmentally assembled prefabricated piers with dry joints. The effectiveness and applicability of EREDDs in improving the seismic performance of PS-CFST bridge piers were studied through the cyclic tests. The inelastic cyclic response of PS-CFST bridge pier specimens with different arrangements of EREDDs was experimentally examined. A detailed account of the test results was provided and discussed, including the stiffness and strength characteristics, strain distributions, residual displacements, failure patterns, as well as hysteretic response and energy dissipation capability. Particular attention was also given within the experimental assessment to investigating the effects of the inter-segmental joint opening positions for the different EREDD arrangements on the seismic response of PS-CFST bridge piers. Based on the experimental findings, an analytical approach was developed for determining the hysteretic response of the proposed PS-CFST bridge piers incorporating EREDDs, offering the basis for their design and assessment in practice. Finally, the results indicate that EREDDs could effectively improve the seismic performance of PS-CFST bridge piers and the hysteretic response could be accurately predicted by using the proposed analytical approach. In addition, EREDDs allow the damage of PS-CFST bridge piers to be concentrated within the easily replaceable component, and thereby facilitating the controlled damage. This study provides an effective method for the seismic design of PS-CFST bridge piers incorporating EREDDs.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109156"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-12DOI: 10.1016/j.jcsr.2024.109135
Sibo Qian , Xiuli Xu , Jian Guan , Rengui Wang , Chong Wu , Changqing Chu , Zhijun Li , Xuehong Li
To mitigate the risk of fatigue cracking in orthotropic steel decks (OSDs), this study proposed a new open-rib orthotropic steel deck (NOSD). The NOSD incorporates spherical flat steel open ribs and apple-shaped cut-outs in the floorbeam. The fatigue performance in the floorbeam region of the NOSD was evaluated through numerical analysis and fatigue tests and compared with that of a conventional double-sided welded U-rib orthotropic steel deck (UOSD). The results indicate that the NOSD effectively eliminates the fatigue cracking mode at the rib-to-deck welded joint, ensuring that this area is no longer fatigue critical. Under the most unfavorable loading conditions, the primary factor contributing to fatigue damage on the floorbeam side of the rib-to-floorbeam welded joint of the NOSD is out-of-plane stress, whereas in-plane stress is the main fatigue damage factor in the arc cutouts. Compared with the UOSD, the NOSD exhibited a significantly longer fatigue life, highlighting its enhanced fatigue resistance. The fatigue cracking modes in the floorbeam region of the NOSD include cracks initiating near the weld toe on the floorbeam side and propagating upward along the weld, as well as cracks starting at the arcs of the two cutouts, expanding toward the center, and ultimately intersecting.
{"title":"Fatigue behavior in the Floorbeam region of new open-rib orthotropic steel deck","authors":"Sibo Qian , Xiuli Xu , Jian Guan , Rengui Wang , Chong Wu , Changqing Chu , Zhijun Li , Xuehong Li","doi":"10.1016/j.jcsr.2024.109135","DOIUrl":"10.1016/j.jcsr.2024.109135","url":null,"abstract":"<div><div>To mitigate the risk of fatigue cracking in orthotropic steel decks (OSDs), this study proposed a new open-rib orthotropic steel deck (NOSD). The NOSD incorporates spherical flat steel open ribs and apple-shaped cut-outs in the floorbeam. The fatigue performance in the floorbeam region of the NOSD was evaluated through numerical analysis and fatigue tests and compared with that of a conventional double-sided welded U-rib orthotropic steel deck (UOSD). The results indicate that the NOSD effectively eliminates the fatigue cracking mode at the rib-to-deck welded joint, ensuring that this area is no longer fatigue critical. Under the most unfavorable loading conditions, the primary factor contributing to fatigue damage on the floorbeam side of the rib-to-floorbeam welded joint of the NOSD is out-of-plane stress, whereas in-plane stress is the main fatigue damage factor in the arc cutouts. Compared with the UOSD, the NOSD exhibited a significantly longer fatigue life, highlighting its enhanced fatigue resistance. The fatigue cracking modes in the floorbeam region of the NOSD include cracks initiating near the weld toe on the floorbeam side and propagating upward along the weld, as well as cracks starting at the arcs of the two cutouts, expanding toward the center, and ultimately intersecting.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109135"},"PeriodicalIF":4.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-11DOI: 10.1016/j.jcsr.2024.109136
Lan Kang , Jufei Jin , Xinpei Liu , Haizhou Chen
Laser-cladding (LC) additive manufacturing technology can be applied to repair local damage in steel structures. However, the process creates a distinctive surface morphology due to the overlap of weld beads on the repair surface, resulting in noticeable pit defects between adjacent weld beads. Under specific load conditions, these defects, or saying surface roughness, may cause significant stress concentration in localised areas of LC additively manufactured sheets. This stress concentration could adversely impact the mechanical properties of the LC additively manufactured sheets, including their stiffness, strength and ductility. This paper addresses this issue by testing smooth and rough surface tensile coupon specimens with different thicknesses produced by laser-cladding additive manufacturing technology. The rough surface specimens were geometrically characterised in detail by using 3D scanning technique, and the thickness distribution characteristics of the rough surface specimens were analysed based on the 3D scanning results. Tensile tests were then conducted on both smooth and rough surface specimens of different thicknesses, revealing that surface roughness indeed adversely affects the mechanical parameters of the LC sheets. The degree of degradation was also found to be related to the thickness of the specimens. Accordingly, a correlation analysis was performed among the degree of degradation, surface roughness and specimen thickness. Empirical formulae were proposed to predict the degree of degradation in the mechanical properties of the LC sheets due to surface roughness based on the results of the correlation analysis.
{"title":"Effects of surface roughness on mechanical properties of laser-cladding additively manufactured 316L stainless steel sheets","authors":"Lan Kang , Jufei Jin , Xinpei Liu , Haizhou Chen","doi":"10.1016/j.jcsr.2024.109136","DOIUrl":"10.1016/j.jcsr.2024.109136","url":null,"abstract":"<div><div>Laser-cladding (LC) additive manufacturing technology can be applied to repair local damage in steel structures. However, the process creates a distinctive surface morphology due to the overlap of weld beads on the repair surface, resulting in noticeable pit defects between adjacent weld beads. Under specific load conditions, these defects, or saying surface roughness, may cause significant stress concentration in localised areas of LC additively manufactured sheets. This stress concentration could adversely impact the mechanical properties of the LC additively manufactured sheets, including their stiffness, strength and ductility. This paper addresses this issue by testing smooth and rough surface tensile coupon specimens with different thicknesses produced by laser-cladding additive manufacturing technology. The rough surface specimens were geometrically characterised in detail by using 3D scanning technique, and the thickness distribution characteristics of the rough surface specimens were analysed based on the 3D scanning results. Tensile tests were then conducted on both smooth and rough surface specimens of different thicknesses, revealing that surface roughness indeed adversely affects the mechanical parameters of the LC sheets. The degree of degradation was also found to be related to the thickness of the specimens. Accordingly, a correlation analysis was performed among the degree of degradation, surface roughness and specimen thickness. Empirical formulae were proposed to predict the degree of degradation in the mechanical properties of the LC sheets due to surface roughness based on the results of the correlation analysis.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109136"},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-10DOI: 10.1016/j.jcsr.2024.109147
Guixiang Xue , Jingli Miao , Dan Zhang , Shixu Zuo , Chen Zhang , Ning Li
Precast segment self-centering concrete filled steel tube (PSCFST) bridge has become a research hotspot in the field of infrastructure because of its excellent seismic performance and self-centering resilience. However, the highly nonlinear response of bridge structures due to their size and complexity poses a serious challenge to the accurate prediction of their seismic response, especially under extreme conditions such as earthquakes. This study presents a prediction method utilizing a temporal convolutional neural network prediction method to accurately forecasting the acceleration response of PSCFST bridge under seismic actions. The dataset was constructed by integrating data obtained from PSCFST single-span bridge shaking table tests and finite element model simulations. The Temporal Convolutional Network (TCN) model is employed as the training architecture, using acceleration time histories from diverse ground motions as inputs and the acceleration response of the bridge's superstructure as the training output. The TCN model employs causal expansion convolution to effectively capture long-term dependence in the time series data of the bridge structure's acceleration response. Furthermore, superposition of residual blocks enables the extraction of more profound nonlinear features at each data layer, thereby facilitating precise forecasting of acceleration responses in the bridge superstructure. The TCN model ensures capturing longer-span temporal correlations while reducing the model parameters, thereby achieving accurate and efficient prediction of bridge seismic response. Detailed comparative experiments were conducted among various algorithmic models, including Recurrent Neural Network (RNN), Long Short-Term Memory (LSTM), Support Vector Regression (SVR), Extreme Gradient Boosting (XGBoost), and Random Forest Regression (RFR). The results validate that the TCN model demonstrates higher prediction accuracy, better generalization capability, faster training speed, and fewer model parameters. These findings comprehensively demonstrate the superiority of the TCN model in predicting bridge vibration responses, offering an effective prediction methodology for enhancing the safety and reliability of bridge structures under seismic actions.
{"title":"Seismic acceleration response prediction method of the PSCFST bridge based on TCN","authors":"Guixiang Xue , Jingli Miao , Dan Zhang , Shixu Zuo , Chen Zhang , Ning Li","doi":"10.1016/j.jcsr.2024.109147","DOIUrl":"10.1016/j.jcsr.2024.109147","url":null,"abstract":"<div><div>Precast segment self-centering concrete filled steel tube (PSCFST) bridge has become a research hotspot in the field of infrastructure because of its excellent seismic performance and self-centering resilience. However, the highly nonlinear response of bridge structures due to their size and complexity poses a serious challenge to the accurate prediction of their seismic response, especially under extreme conditions such as earthquakes. This study presents a prediction method utilizing a temporal convolutional neural network prediction method to accurately forecasting the acceleration response of PSCFST bridge under seismic actions. The dataset was constructed by integrating data obtained from PSCFST single-span bridge shaking table tests and finite element model simulations. The Temporal Convolutional Network (TCN) model is employed as the training architecture, using acceleration time histories from diverse ground motions as inputs and the acceleration response of the bridge's superstructure as the training output. The TCN model employs causal expansion convolution to effectively capture long-term dependence in the time series data of the bridge structure's acceleration response. Furthermore, superposition of residual blocks enables the extraction of more profound nonlinear features at each data layer, thereby facilitating precise forecasting of acceleration responses in the bridge superstructure. The TCN model ensures capturing longer-span temporal correlations while reducing the model parameters, thereby achieving accurate and efficient prediction of bridge seismic response. Detailed comparative experiments were conducted among various algorithmic models, including Recurrent Neural Network (RNN), Long Short-Term Memory (LSTM), Support Vector Regression (SVR), Extreme Gradient Boosting (XGBoost), and Random Forest Regression (RFR). The results validate that the TCN model demonstrates higher prediction accuracy, better generalization capability, faster training speed, and fewer model parameters. These findings comprehensively demonstrate the superiority of the TCN model in predicting bridge vibration responses, offering an effective prediction methodology for enhancing the safety and reliability of bridge structures under seismic actions.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109147"},"PeriodicalIF":4.0,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-08DOI: 10.1016/j.jcsr.2024.109127
B. Kövesdi, D. Kollár, B. Szabó, L. Dunai
Corrosion measurements were performed on the 175-years-old historical Széchenyi Chain Bridge within the last four decades; most lately under its reconstruction process in 2022. Measurement results are evaluated, and the findings encompass the structural corrosion loss of the chain elements (eyebars). A multi-phase nonlinear corrosion model, with time-dependent Weibull distribution parameters, is developed for bridges over rivers in urban environment. The model is capable of considering the time prior to corrosion initiation corresponding to the start of corrosion protection coating failure. Prediction of structural integrity and performance of chain elements is crucial to ensure reliable operation of such a historical structure. Therefore, multiple scenarios of possible corrosion progression are analysed with and without maintenance to estimate the evolution of corrosion damage over time. Probabilistic finite element calculations are carried out to predict the probability of failure of the chain elements subjected to pure tension. Partial safety factor of Eurocode, determined through Monte Carlo simulations with a response surface, ranges from 1.16 to 1.41 for corroded elements, assuming no renewal of the corrosion protection. Renewal of the coating significantly reduces probability, resulting in a partial safety factor of 1.17. Stochastic analysis indicates adequate load-bearing capacity of the chain elements for at least 20 years without significant renewal of the corrosion protection system.
{"title":"Probabilistic failure assessment of steel eyebars by considering multi-phase nonlinear corrosion model","authors":"B. Kövesdi, D. Kollár, B. Szabó, L. Dunai","doi":"10.1016/j.jcsr.2024.109127","DOIUrl":"10.1016/j.jcsr.2024.109127","url":null,"abstract":"<div><div>Corrosion measurements were performed on the 175-years-old historical Széchenyi Chain Bridge within the last four decades; most lately under its reconstruction process in 2022. Measurement results are evaluated, and the findings encompass the structural corrosion loss of the chain elements (eyebars). A multi-phase nonlinear corrosion model, with time-dependent Weibull distribution parameters, is developed for bridges over rivers in urban environment. The model is capable of considering the time prior to corrosion initiation corresponding to the start of corrosion protection coating failure. Prediction of structural integrity and performance of chain elements is crucial to ensure reliable operation of such a historical structure. Therefore, multiple scenarios of possible corrosion progression are analysed with and without maintenance to estimate the evolution of corrosion damage over time. Probabilistic finite element calculations are carried out to predict the probability of failure of the chain elements subjected to pure tension. Partial safety factor of Eurocode, determined through Monte Carlo simulations with a response surface, ranges from 1.16 to 1.41 for corroded elements, assuming no renewal of the corrosion protection. Renewal of the coating significantly reduces probability, resulting in a partial safety factor of 1.17. Stochastic analysis indicates adequate load-bearing capacity of the chain elements for at least 20 years without significant renewal of the corrosion protection system.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109127"},"PeriodicalIF":4.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.jcsr.2024.109145
Son Tung Vy , Anh Tuan Vu
In this research study, based on suitable and rational thermal and sequentially coupled structural FE (finite element) analyses, the fire resistance behaviour and FRLs (fire resistance levels) of non-load bearing LSF (light gauge steel framed) walls with restrained thermal elongation were deeply analysed. The FE analysis results confirmed that CFS (cold-formed steel) channel studs of the mentioned walls collapsed prematurely due to additional compression loads caused by the effects of fire and the thermal elongation restraints at stud ends, which led to the reduced FRLs of these walls. Besides, the wall height and the clearance between the stud ends and rigid floors were shown as having significant effects on the FRLs of non-load bearing LSF walls with restrained thermal elongation. In contrast, the effects of the thickness and depth of CFS channel studs and cavity insulation were inconsiderable. Finally, a simplified and reliable design equation and some recommendations were proposed for some types of non-load bearing fire-rated LSF walls commonly used in Australia. This paper presents details of this study, including its analyses, outcomes, and proposals.
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Steel frame structures repaired after fire exposure exhibit markedly different collapse behavior, compared to their performance under ambient conditions, when subjected to extreme loads. This study investigates the progressive collapse resistance of steel frame structures with reduced beam section (RBS) connections in post-fire conditions, using ten beam-column substructures: one tested at room temperature and nine exposed to various fire conditions. Results show that fire exposure shifts the failure from the RBS to the beam-column connection, significantly impairing the RBS's ability to relocate the plastic hinge, especially at higher fire temperatures. Fire temperature significantly affects collapse resistance, especially above 600 °C, whereas fire duration has a comparatively smaller influence on deformation capacity, particularly at 800 °C. Elevated temperatures weaken tensile catenary action (TCA), with substructures exposed to 800 °C for 90 min failing to transition to the TCA-dominated stage. Numerical simulations show that for substructures exposed to 400 °C and 600 °C, collapse resistance increases with greater flange reduction length, while the relationship between collapse resistance and starting reduction distance follows a rise-and-fall pattern. At 800 °C, collapse resistance remains relatively consistent across different starting reduction distances, but increasing the reduction length initially enhances and then reduces resistance. Increasing the reduction depth to 30 mm significantly reduces both the flexural and tensile capacities of the RBS region, shifting the failure mode from the beam-column connection to the RBS region.
{"title":"Post-fire progressive collapse resistance of beam-column substructures with RBS connections","authors":"Weiwei Zhang , Zhijun Xu , Haolong Xu , Wanpeng Zhang , Zongcheng Wang , Yu Chen","doi":"10.1016/j.jcsr.2024.109137","DOIUrl":"10.1016/j.jcsr.2024.109137","url":null,"abstract":"<div><div>Steel frame structures repaired after fire exposure exhibit markedly different collapse behavior, compared to their performance under ambient conditions, when subjected to extreme loads. This study investigates the progressive collapse resistance of steel frame structures with reduced beam section (RBS) connections in post-fire conditions, using ten beam-column substructures: one tested at room temperature and nine exposed to various fire conditions. Results show that fire exposure shifts the failure from the RBS to the beam-column connection, significantly impairing the RBS's ability to relocate the plastic hinge, especially at higher fire temperatures. Fire temperature significantly affects collapse resistance, especially above 600 °C, whereas fire duration has a comparatively smaller influence on deformation capacity, particularly at 800 °C. Elevated temperatures weaken tensile catenary action (TCA), with substructures exposed to 800 °C for 90 min failing to transition to the TCA-dominated stage. Numerical simulations show that for substructures exposed to 400 °C and 600 °C, collapse resistance increases with greater flange reduction length, while the relationship between collapse resistance and starting reduction distance follows a rise-and-fall pattern. At 800 °C, collapse resistance remains relatively consistent across different starting reduction distances, but increasing the reduction length initially enhances and then reduces resistance. Increasing the reduction depth to 30 mm significantly reduces both the flexural and tensile capacities of the RBS region, shifting the failure mode from the beam-column connection to the RBS region.</div></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":"224 ","pages":"Article 109137"},"PeriodicalIF":4.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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