Pub Date : 2024-11-23DOI: 10.1016/j.engstruct.2024.119367
Longxuan Wang , Hongbo Liu , Fan Zhang , Liulu Guo , Zhihua Chen
Global spatial structures face potential safety hazards as they age and are subjected to external influences. As traditional response and performance deterioration prediction methods have exhibited limitations when dealing with long time-series data and spatially complex features, this study proposed a novel approach integrating spatiotemporal deep learning (SDL) and digital twins (DT) to address this challenge. An SDL framework driven by component strain data from physical monitoring was proposed to predict the structural responses. Three time-series deep learning frameworks were proposed to predict ambient trends, which were input in a DT model to output the structural responses driven by virtual future ambient data. Then errors of both are fused through a proposed deep neural network to improve the final prediction accuracy. Finally, deterioration prediction was achieved by comparing the deviations between the final predicted performance responses and those calculated in real time from the initial structure’s DT replica, both in the same ambient conditions. The proposed approach, verified through a long-term health monitoring experiment of a scaled cable dome structure, demonstrated high precision, with the maximum mean error of cable strain deterioration prediction only 10.45 με. It can provide a new intelligent solution for the safe operation and maintenance of spatial structures.
{"title":"Intelligent prediction approach of spatial structure response and performance deterioration by integrating spatiotemporal deep learning and digital twins","authors":"Longxuan Wang , Hongbo Liu , Fan Zhang , Liulu Guo , Zhihua Chen","doi":"10.1016/j.engstruct.2024.119367","DOIUrl":"10.1016/j.engstruct.2024.119367","url":null,"abstract":"<div><div>Global spatial structures face potential safety hazards as they age and are subjected to external influences. As traditional response and performance deterioration prediction methods have exhibited limitations when dealing with long time-series data and spatially complex features, this study proposed a novel approach integrating spatiotemporal deep learning (SDL) and digital twins (DT) to address this challenge. An SDL framework driven by component strain data from physical monitoring was proposed to predict the structural responses. Three time-series deep learning frameworks were proposed to predict ambient trends, which were input in a DT model to output the structural responses driven by virtual future ambient data. Then errors of both are fused through a proposed deep neural network to improve the final prediction accuracy. Finally, deterioration prediction was achieved by comparing the deviations between the final predicted performance responses and those calculated in real time from the initial structure’s DT replica, both in the same ambient conditions. The proposed approach, verified through a long-term health monitoring experiment of a scaled cable dome structure, demonstrated high precision, with the maximum mean error of cable strain deterioration prediction only 10.45 με. It can provide a new intelligent solution for the safe operation and maintenance of spatial structures.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119367"},"PeriodicalIF":5.6,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1016/j.engstruct.2024.119327
Bowen Sun , Yang Zhang , Chong Zhao , Ruixiang Shi , Haifeng Zhao , Qiang Sheng , Ke Wang
Thick-panel origami has gained significant attention for its potential applications in the design of space deployable arrays. However, existing origami structures often fail to meet the stringent constraints imposed by various spacecraft in terms of connectivity and space efficiency, limiting the achievement of optimal folding ratios and compact transportation. To address these challenges, we propose a parameterized geometric model and design method for center-symmetric thick-panel space deployable arrays for varying scales and functions, integrating five-crease vertices with Miura origami. A planar four-bar linkage mechanism is applied to coordinate the motion between the five-crease vertices and Miura origami, ensuring one-degree-of-freedom (one-DOF) motion. The proposed model is validated through a case study on a space exposure experiment platform, with a scaled-down prototype fabricated for testing. The resulting space deployable arrays can be compactly placed within a rectangular prism, offering central symmetry, one-DOF motion, high volume efficiency and folding ratio, and enhanced design flexibility and adaptability.
{"title":"A parameterized model of center-symmetric space deployable arrays inspired by Miura and five-crease origami","authors":"Bowen Sun , Yang Zhang , Chong Zhao , Ruixiang Shi , Haifeng Zhao , Qiang Sheng , Ke Wang","doi":"10.1016/j.engstruct.2024.119327","DOIUrl":"10.1016/j.engstruct.2024.119327","url":null,"abstract":"<div><div>Thick-panel origami has gained significant attention for its potential applications in the design of space deployable arrays. However, existing origami structures often fail to meet the stringent constraints imposed by various spacecraft in terms of connectivity and space efficiency, limiting the achievement of optimal folding ratios and compact transportation. To address these challenges, we propose a parameterized geometric model and design method for center-symmetric thick-panel space deployable arrays for varying scales and functions, integrating five-crease vertices with Miura origami. A planar four-bar linkage mechanism is applied to coordinate the motion between the five-crease vertices and Miura origami, ensuring one-degree-of-freedom (one-DOF) motion. The proposed model is validated through a case study on a space exposure experiment platform, with a scaled-down prototype fabricated for testing. The resulting space deployable arrays can be compactly placed within a rectangular prism, offering central symmetry, one-DOF motion, high volume efficiency and folding ratio, and enhanced design flexibility and adaptability.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119327"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1016/j.engstruct.2024.119326
Yaping Lai , Qi Cai , Yu Li , Jiayong Chen , Yi Min Xie
This paper presents a new topology optimization method and a comprehensive workflow for the practical design of truss structures. It begins with discussing practical design requirements for truss topology optimization and then introduces a technique for creating arbitrarily shaped ground structures suitable for complex geometries. To address limitations in current truss optimization methods, we propose a dual-material truss-bidirectional evolutionary structural optimization (DMT-BESO) method. This approach utilizes two materials that differ significantly in tensile and compressive allowable stresses and moduli of elasticity. The DMT-BESO method integrates the minimum energy principle with the full-stress design criterion, using bar cross-sectional areas as design variables to achieve simultaneous topology and size optimization. By considering stress constraints, this method ensures compliance with industry standards, enhancing both safety and material utilization. Additionally, a structural complexity control strategy is proposed to generate a near-optimal truss design and simplify the optimized design while maintaining efficiency, making it more suitable for practical applications. The effectiveness of the DMT-BESO method and its complexity control strategy is validated through numerical examples and the design of an arch bridge of composite materials.
{"title":"A new evolutionary topology optimization method for truss structures towards practical design applications","authors":"Yaping Lai , Qi Cai , Yu Li , Jiayong Chen , Yi Min Xie","doi":"10.1016/j.engstruct.2024.119326","DOIUrl":"10.1016/j.engstruct.2024.119326","url":null,"abstract":"<div><div>This paper presents a new topology optimization method and a comprehensive workflow for the practical design of truss structures. It begins with discussing practical design requirements for truss topology optimization and then introduces a technique for creating arbitrarily shaped ground structures suitable for complex geometries. To address limitations in current truss optimization methods, we propose a dual-material truss-bidirectional evolutionary structural optimization (DMT-BESO) method. This approach utilizes two materials that differ significantly in tensile and compressive allowable stresses and moduli of elasticity. The DMT-BESO method integrates the minimum energy principle with the full-stress design criterion, using bar cross-sectional areas as design variables to achieve simultaneous topology and size optimization. By considering stress constraints, this method ensures compliance with industry standards, enhancing both safety and material utilization. Additionally, a structural complexity control strategy is proposed to generate a near-optimal truss design and simplify the optimized design while maintaining efficiency, making it more suitable for practical applications. The effectiveness of the DMT-BESO method and its complexity control strategy is validated through numerical examples and the design of an arch bridge of composite materials.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119326"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1016/j.engstruct.2024.119347
Chen Lin , Zhanchong Shi , Terje Kanstad , Mohammad Haj Mohammadian Baghban , Guomin Ji
Despite the outstanding mechanical properties, SFRC is still underutilized in the load-bearing structures, mainly being restrained to the non-structural applications. This paper primarily investigates the effect of the innovative combination of steel fibers and the post-tensioning on the performance of concrete slabs and assesses the feasibility of using steel fiber as substitute for the conventional reinforcement in post-tensioned slabs. Building on the experimental work done by Virginia Polytechnic Institute and State University, numerical and theoretical analyses were employed to verify and extend the experimental findings. In the paper, two different reinforcement solutions (steel fibers or conventional reinforcement) were used in the slabs, and they were combined with four different tendon layouts. Among them, the banded-banded tendon coupled with steel fibers significantly enhanced the punching shear resistance of the slabs. To deepen the understanding of SFRC’s viability as a structural material, the flexural strength of the slabs obtained from nonlinear finite element analysis (NLFEA) is compared against the theoretical results of design methods outlined in fib Model Code 2010 (MC2010), new FprEC2:2022 (prEN 1992–1-1:2022(E)), IAPMO UES ER-465 (IAPMO 465), and Norwegian NB 38 (NB 38). The results indicates that some of the certain provisions in the American and European Codes might be simplified, for instance: 1) steel fibers might be used as the only reinforcement to replace the minimum required bar reinforcement in post-tensioned slabs, and 2) combination of steel fibers and banded tendon layout, which could further simplify the construction process, might be applied in the engineering construction.
{"title":"Application of steel fiber reinforced-concrete in post-tensioned flat slabs: A numerical study","authors":"Chen Lin , Zhanchong Shi , Terje Kanstad , Mohammad Haj Mohammadian Baghban , Guomin Ji","doi":"10.1016/j.engstruct.2024.119347","DOIUrl":"10.1016/j.engstruct.2024.119347","url":null,"abstract":"<div><div>Despite the outstanding mechanical properties, SFRC is still underutilized in the load-bearing structures, mainly being restrained to the non-structural applications. This paper primarily investigates the effect of the innovative combination of steel fibers and the post-tensioning on the performance of concrete slabs and assesses the feasibility of using steel fiber as substitute for the conventional reinforcement in post-tensioned slabs. Building on the experimental work done by Virginia Polytechnic Institute and State University, numerical and theoretical analyses were employed to verify and extend the experimental findings. In the paper, two different reinforcement solutions (steel fibers or conventional reinforcement) were used in the slabs, and they were combined with four different tendon layouts. Among them, the banded-banded tendon coupled with steel fibers significantly enhanced the punching shear resistance of the slabs. To deepen the understanding of SFRC’s viability as a structural material, the flexural strength of the slabs obtained from nonlinear finite element analysis (NLFEA) is compared against the theoretical results of design methods outlined in <em>fib</em> Model Code 2010 (MC2010), new FprEC2:2022 (prEN 1992–1-1:2022(E)), IAPMO UES ER-465 (IAPMO 465), and Norwegian NB 38 (NB 38). The results indicates that some of the certain provisions in the American and European Codes might be simplified, for instance: 1) steel fibers might be used as the only reinforcement to replace the minimum required bar reinforcement in post-tensioned slabs, and 2) combination of steel fibers and banded tendon layout, which could further simplify the construction process, might be applied in the engineering construction.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119347"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1016/j.engstruct.2024.119290
Zhikang Deng , Lingzhen Li , Vlad-Alexandru Silvestru , Elyas Ghafoori , Andreas Taras
Glass beams have been widely used as structural elements. However, glass is brittle, and the load-carrying capacity of glass beams after cracking is quite low. Adhesively bonded pre-stressed iron-based shape memory alloy (Fe-SMA) tendons can effectively increase the initial glass cracking load, the post-cracking load-carrying capacity, and the deformability of glass beams. Activation, which involves controlled heating followed by natural cooling, is one of the key processes of such an application to attain the target pre-stress levels. The effectiveness of activation depends on the activation length (over which the Fe-SMA strips were activated), anchorage length and activation temperature. A deep understanding of the activation strategy is crucial for maximizing pre-stress levels while avoiding premature failures such as glass breakage or debonding during activation. In this study, first, activation strategies for Fe-SMA-to-glass adhesively bonded joints were investigated experimentally by considering various activation temperatures and activation lengths, aiming to attain high pre-stress levels while avoiding glass breakage and debonding. Second, the effect of elevated service temperature (50 °C and 80 °C) on the pre-stress loss was investigated for the same specimens. Third, a finite element model was developed to investigate the different activation strategies further. The results showed that (1) the segmented activation strategy improved stress concentration compared with the single-cycle activation strategy, (2) the pre-stress was completely lost when the service temperature was 50 °C and 80 °C, (3) longer activation lengths resulted in a relatively lower pre-stress level, and (4) increasing the activation temperature substantially raised the pre-stress level. The findings in this research will contribute to the efficient design and application of pre-stressing glass elements using adhesively bonded Fe-SMA tendons.
{"title":"Investigation on the effects of activation strategies and service temperature on the pre-stress levels of Fe-SMA-to-glass adhesively bonded joints","authors":"Zhikang Deng , Lingzhen Li , Vlad-Alexandru Silvestru , Elyas Ghafoori , Andreas Taras","doi":"10.1016/j.engstruct.2024.119290","DOIUrl":"10.1016/j.engstruct.2024.119290","url":null,"abstract":"<div><div>Glass beams have been widely used as structural elements. However, glass is brittle, and the load-carrying capacity of glass beams after cracking is quite low. Adhesively bonded pre-stressed iron-based shape memory alloy (Fe-SMA) tendons can effectively increase the initial glass cracking load, the post-cracking load-carrying capacity, and the deformability of glass beams. Activation, which involves controlled heating followed by natural cooling, is one of the key processes of such an application to attain the target pre-stress levels. The effectiveness of activation depends on the activation length (over which the Fe-SMA strips were activated), anchorage length and activation temperature. A deep understanding of the activation strategy is crucial for maximizing pre-stress levels while avoiding premature failures such as glass breakage or debonding during activation. In this study, first, activation strategies for Fe-SMA-to-glass adhesively bonded joints were investigated experimentally by considering various activation temperatures and activation lengths, aiming to attain high pre-stress levels while avoiding glass breakage and debonding. Second, the effect of elevated service temperature (50 °C and 80 °C) on the pre-stress loss was investigated for the same specimens. Third, a finite element model was developed to investigate the different activation strategies further. The results showed that (1) the segmented activation strategy improved stress concentration compared with the single-cycle activation strategy, (2) the pre-stress was completely lost when the service temperature was 50 °C and 80 °C, (3) longer activation lengths resulted in a relatively lower pre-stress level, and (4) increasing the activation temperature substantially raised the pre-stress level. The findings in this research will contribute to the efficient design and application of pre-stressing glass elements using adhesively bonded Fe-SMA tendons.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119290"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1016/j.engstruct.2024.119341
Vladimir Rybakov , Kseniia Usanova , Pavel Kozlov
Steel thin-walled profiles are the backbone of modern lightweight construction, offering exceptional efficiency in terms of material use and assembly speed. However, their inherent susceptibility to buckling under complex loading conditions, especially bending torsion, has limited their broader application in advanced structural systems. This paper introduces a groundbreaking method for analyzing the bending-torsion behavior of steel thin-walled C-profile beams, specifically focusing on the critical but often overlooked factor of support warping stiffness. Unlike conventional studies that primarily examine local or global buckling resistance, this research pioneers a comprehensive approach that integrates the warping stiffness of supports into the structural analysis. Through the introduction of novel coefficients—warping (0.377–0.484) and bending (0.616–0.672)—this study established a new paradigm in the design and stability analysis of thin-walled beams. Our findings reveal that incorporating support warping stiffness can dramatically increase normal stresses by 2–4 times within the span, a revelation that significantly alters existing design assumptions. The study also demonstrated how sectorial stiffness, a key parameter, directly enhances the warping stiffness of the supports, while the bending stiffness of the beam has negligible impact on the compliance factor. This novel insight provided a substantial leap forward in accurately predicting the complex interaction between bending and torsion in lightweight steel structures. By addressing a critical gap in the literature, this research not only advances the theoretical understanding of thin-walled profiles but also offers practical implications for optimizing the structural design of modern construction systems, enhancing both performance and safety.
薄壁型钢是现代轻质结构的支柱，在材料使用和组装速度方面具有卓越的效率。然而，在复杂载荷条件下，尤其是弯曲扭转条件下，薄壁型钢固有的易屈性限制了其在先进结构系统中的广泛应用。本文介绍了一种分析薄壁 C 型钢梁弯曲扭转行为的开创性方法，特别关注支撑翘曲刚度这一关键但经常被忽视的因素。与主要研究局部或整体抗弯的传统研究不同，本研究开创了一种将支撑翘曲刚度纳入结构分析的综合方法。通过引入新的系数--翘曲系数（0.377-0.484）和弯曲系数（0.616-0.672），这项研究为薄壁梁的设计和稳定性分析建立了新的范例。我们的研究结果表明，加入支撑翘曲刚度后，跨度内的法向应力会显著增加 2-4 倍，这大大改变了现有的设计假设。研究还证明了扇形刚度这一关键参数如何直接增强支撑的翘曲刚度，而梁的弯曲刚度对顺应系数的影响却微乎其微。这一新颖见解为准确预测轻型钢结构中弯曲和扭转之间复杂的相互作用提供了实质性的飞跃。通过解决文献中的关键空白，这项研究不仅推进了对薄壁型材的理论理解，还为优化现代建筑系统的结构设计、提高性能和安全性提供了实际意义。
{"title":"Bending torsion of steel thin-walled beams, considering support warping stiffness","authors":"Vladimir Rybakov , Kseniia Usanova , Pavel Kozlov","doi":"10.1016/j.engstruct.2024.119341","DOIUrl":"10.1016/j.engstruct.2024.119341","url":null,"abstract":"<div><div>Steel thin-walled profiles are the backbone of modern lightweight construction, offering exceptional efficiency in terms of material use and assembly speed. However, their inherent susceptibility to buckling under complex loading conditions, especially bending torsion, has limited their broader application in advanced structural systems. This paper introduces a groundbreaking method for analyzing the bending-torsion behavior of steel thin-walled C-profile beams, specifically focusing on the critical but often overlooked factor of support warping stiffness. Unlike conventional studies that primarily examine local or global buckling resistance, this research pioneers a comprehensive approach that integrates the warping stiffness of supports into the structural analysis. Through the introduction of novel coefficients—warping (0.377–0.484) and bending (0.616–0.672)—this study established a new paradigm in the design and stability analysis of thin-walled beams. Our findings reveal that incorporating support warping stiffness can dramatically increase normal stresses by 2–4 times within the span, a revelation that significantly alters existing design assumptions. The study also demonstrated how sectorial stiffness, a key parameter, directly enhances the warping stiffness of the supports, while the bending stiffness of the beam has negligible impact on the compliance factor. This novel insight provided a substantial leap forward in accurately predicting the complex interaction between bending and torsion in lightweight steel structures. By addressing a critical gap in the literature, this research not only advances the theoretical understanding of thin-walled profiles but also offers practical implications for optimizing the structural design of modern construction systems, enhancing both performance and safety.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119341"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper addresses the lack of current Chinese seismic-resistant design principles and methods for track structures in the bridge-embankment transition zone of multi-span High-Speed Railway Simply Supported Bridges (HSRSBs), an area prone to high damage risk. To decouple the seismic-resistant design of track structures from bridge structures, the paper introduces the design principle of Negligible Change in Fundamental Frequency (NCF). Building on this principle, the paper proposes an easily implementable design approach called Friction Slab Extension (FSE), which reduces track internal forces by extending the length of the friction slab without requiring additional seismic-resistant equipment. Through numerical seismic simulations validated by experimental data, the effectiveness of FSE in reducing internal forces in the track of the bridge-embankment transition zone is confirmed. The study also determines the Recommended Length of Friction Slab (RLFS) for practical engineering implementation based on the response reduction limit. Seismic vulnerability analyses demonstrate that adopting the FSE with RLFS effectively mitigates the risk of track structure failure, evidenced by a 15 % reduction in exceedance probabilities under considerable levels. Importantly, this approach ensures that the seismic performance of the bridge components remains unaffected, in line with the expectations of the NCF principle. These findings underscore the efficacy of the FSE and the rationality of the NCF principle, offering valuable guidance for future design developments.
多跨高速铁路简支梁桥（HSRSB）的桥-堤过渡区是易发生高风险破坏的区域，本文针对该区域的轨道结构缺乏现行的中国抗震设计原则和方法。为了使轨道结构的抗震设计与桥梁结构脱钩，本文引入了基频微小变化（Negligible Change in Fundamental Frequency，NCF）设计原则。在此原则基础上，本文提出了一种易于实施的设计方法，即摩擦板延伸（FSE），通过延长摩擦板的长度来降低轨道内力，而无需额外的抗震设备。通过试验数据验证的地震数值模拟，证实了 FSE 在减少桥梁-堤坝过渡区轨道内力方面的有效性。研究还根据反应减弱极限确定了实际工程实施的摩擦板推荐长度（RLFS）。地震脆弱性分析表明，采用带 RLFS 的 FSE 可以有效降低轨道结构破坏的风险，在相当高的水平下，超限概率降低了 15%。重要的是，这种方法确保桥梁部件的抗震性能不受影响，符合 NCF 原则的预期。这些发现强调了 FSE 的有效性和 NCF 原则的合理性，为未来的设计开发提供了宝贵的指导。
{"title":"A novel seismic-resistant design for track structures in the bridge-embankment transition zone of multi-span high-speed railways simply supported bridges","authors":"Lizhong Jiang , Bufan Zhong , Yuntai Zhang , Wangbao Zhou , Zhipeng Lai","doi":"10.1016/j.engstruct.2024.119349","DOIUrl":"10.1016/j.engstruct.2024.119349","url":null,"abstract":"<div><div>This paper addresses the lack of current Chinese seismic-resistant design principles and methods for track structures in the bridge-embankment transition zone of multi-span High-Speed Railway Simply Supported Bridges (HSRSBs), an area prone to high damage risk. To decouple the seismic-resistant design of track structures from bridge structures, the paper introduces the design principle of Negligible Change in Fundamental Frequency (NCF). Building on this principle, the paper proposes an easily implementable design approach called Friction Slab Extension (FSE), which reduces track internal forces by extending the length of the friction slab without requiring additional seismic-resistant equipment. Through numerical seismic simulations validated by experimental data, the effectiveness of FSE in reducing internal forces in the track of the bridge-embankment transition zone is confirmed. The study also determines the Recommended Length of Friction Slab (RLFS) for practical engineering implementation based on the response reduction limit. Seismic vulnerability analyses demonstrate that adopting the FSE with RLFS effectively mitigates the risk of track structure failure, evidenced by a 15 % reduction in exceedance probabilities under considerable levels. Importantly, this approach ensures that the seismic performance of the bridge components remains unaffected, in line with the expectations of the NCF principle. These findings underscore the efficacy of the FSE and the rationality of the NCF principle, offering valuable guidance for future design developments.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119349"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1016/j.engstruct.2024.119324
Lingzhu Zhou , Yong Yu , Yu Zheng , Yuxiao Ye , Yiren Wang , Jingzhi Lao
The combination of glass fiber reinforced polymer (GFRP) bars and polyoxymethylene (POM) fiber reinforced ultra-high performance concrete (UHPC) can create a structural system with excellent service performance and exceptional durability. Bond is a critical factor affecting the service performance of structures constructed using GFRP bars and POM fiber reinforced UHPC. Therefore, this paper investigates the bond behavior between GFRP bar and POM fiber reinforced UHPC by using a direct pull-out test. The test variables were reinforcement type, volume fraction of POM fiber, embedment length, diameter of reinforcement, thickness of concrete cover, and compressive strength of concrete. The effects of these test variables on the failure mode, bond stress-slip curve and bond strength of GFRP bar with POM fiber reinforced UHPC were discussed. The test results revealed that the volume fraction of POM fibers and the reinforcement diameter have barely effect on the bond strength. The bond strength initially increases with increasing concrete cover thickness, and then plateaus after the concrete cover thickness reaches 3.35 times the reinforcement diameter. Furthermore, a predictive model for bond strength of GFRP reinforced UHPC specimens was proposed and validated using test data from other literature. A general bond-slip constitutive model was established to accurately describe the bond-slip relationship of GFRP bar and UHPC.
{"title":"Investigation on bond behavior of GFRP bar embedded in ultra-high performance polyoxymethylene fiber reinforced concrete","authors":"Lingzhu Zhou , Yong Yu , Yu Zheng , Yuxiao Ye , Yiren Wang , Jingzhi Lao","doi":"10.1016/j.engstruct.2024.119324","DOIUrl":"10.1016/j.engstruct.2024.119324","url":null,"abstract":"<div><div>The combination of glass fiber reinforced polymer (GFRP) bars and polyoxymethylene (POM) fiber reinforced ultra-high performance concrete (UHPC) can create a structural system with excellent service performance and exceptional durability. Bond is a critical factor affecting the service performance of structures constructed using GFRP bars and POM fiber reinforced UHPC. Therefore, this paper investigates the bond behavior between GFRP bar and POM fiber reinforced UHPC by using a direct pull-out test. The test variables were reinforcement type, volume fraction of POM fiber, embedment length, diameter of reinforcement, thickness of concrete cover, and compressive strength of concrete. The effects of these test variables on the failure mode, bond stress-slip curve and bond strength of GFRP bar with POM fiber reinforced UHPC were discussed. The test results revealed that the volume fraction of POM fibers and the reinforcement diameter have barely effect on the bond strength. The bond strength initially increases with increasing concrete cover thickness, and then plateaus after the concrete cover thickness reaches 3.35 times the reinforcement diameter. Furthermore, a predictive model for bond strength of GFRP reinforced UHPC specimens was proposed and validated using test data from other literature. A general bond-slip constitutive model was established to accurately describe the bond-slip relationship of GFRP bar and UHPC.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119324"},"PeriodicalIF":5.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-21DOI: 10.1016/j.engstruct.2024.119316
Dawei Gu , Bo Jiang , Jingting Lin , Li Xu , Jinlong Pan
Steel-concrete composite girders are extensively used in long-span bridges because of their high strength-to-weight ratios and ease of construction. However, concrete cracking can weaken the steel-concrete shear connections, particularly when the concrete layer is subjected to tension, such as in continuous bridge decks under negative moments at mid-supports. Replacing brittle concrete with ductile engineered cementitious composites (ECC) offers a promising solution for improving crack control and maintaining effective shear transfer between layers. This study investigates the shear transfer behaviour of steel-headed stud connectors in ECC under positive and negative moments using push-out and inverse push-out tests. A total of 23 H-shaped steel-ECC composite specimens are tested to examine the effects of loading direction, matrix type, reinforcement ratio, stud length and diameter, and ECC layer thickness. The experimental results indicate that the shear-carrying capacity and slipping ability of steel-headed stud connectors in ECC are significantly higher than those in conventional concrete under negative moments. Furthermore, a numerical analysis is conducted to examine the influence of boundary conditions and ECC material properties on the shear performance of studs. The shear transfer mechanism of studs in ECC was elucidated through a refined finite element model. Finally, existing equations for predicting the ultimate stud connection strength in concrete or ECC are evaluated against the test results. This research provides insights into the design of shear connections in steel-ECC composite structures, particularly for applications involving negative moments.
{"title":"Shear behaviour of steel-headed stud connectors in engineered cementitious composite (ECC) bridge deck under positive and negative moments","authors":"Dawei Gu , Bo Jiang , Jingting Lin , Li Xu , Jinlong Pan","doi":"10.1016/j.engstruct.2024.119316","DOIUrl":"10.1016/j.engstruct.2024.119316","url":null,"abstract":"<div><div>Steel-concrete composite girders are extensively used in long-span bridges because of their high strength-to-weight ratios and ease of construction. However, concrete cracking can weaken the steel-concrete shear connections, particularly when the concrete layer is subjected to tension, such as in continuous bridge decks under negative moments at mid-supports. Replacing brittle concrete with ductile engineered cementitious composites (ECC) offers a promising solution for improving crack control and maintaining effective shear transfer between layers. This study investigates the shear transfer behaviour of steel-headed stud connectors in ECC under positive and negative moments using push-out and inverse push-out tests. A total of 23 H-shaped steel-ECC composite specimens are tested to examine the effects of loading direction, matrix type, reinforcement ratio, stud length and diameter, and ECC layer thickness. The experimental results indicate that the shear-carrying capacity and slipping ability of steel-headed stud connectors in ECC are significantly higher than those in conventional concrete under negative moments. Furthermore, a numerical analysis is conducted to examine the influence of boundary conditions and ECC material properties on the shear performance of studs. The shear transfer mechanism of studs in ECC was elucidated through a refined finite element model. Finally, existing equations for predicting the ultimate stud connection strength in concrete or ECC are evaluated against the test results. This research provides insights into the design of shear connections in steel-ECC composite structures, particularly for applications involving negative moments.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119316"},"PeriodicalIF":5.6,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-21DOI: 10.1016/j.engstruct.2024.119328
Quanwu Zhang , Weixing Shi , Yuting Ouyang
The vibration and noise induced by the operation of subway trains cause disturbances to the adjacent building structures. The serviceability of building structures (i.e., offices and residences) in terms of the annoyance of humans is sensitive to vibration and noise; therefore, it is necessary to conduct an effective vibration control strategy for building structures in terms of the structure-born noise and vibration protection. In serviceability-related vibration control, two issues are considered herein: (a) the irregularity of the controlled structure and (b) the structure uncertainties, such as insufficient knowledge about the structural mass redistributed in the isolation system. A quasi-constant natural frequency (QCNF) pad, mixed with rubber and foam material, is introduced herein to tackle these two issues. Such a system is nonlinear, and its stiffness is associated with the structural mass distribution. In this paper, a single-degree-of-freedom (SDOF) system is employed first to illustrate the property of a QCNF system. Inspired by the ideal load-displacement property of a QCNF system, a streamlined rubber element, an unconstrained cylinder rubber element, and two constrained cylinder rubber elements (including rigidly constrained and flexibly constrained) are designed and simulated with a finite element model. The physical properties of such four designed elements are obtained based on a static testing and an ambient field test. In the end, a quasi-constant frequency isolation pad mixed with rubber and foam material has been comprehensively discussed regarding the finite element simulation and an on-site ground-borne vibration test validation. The results indicate that the flexibly constrained QCNF rubber pad, using a combination of rubber and foam materials, can maintain a nearly constant frequency in the range of 67–1000 kPa load. The test validation based on a real-world application of the QCNF rubber pad indicates its feasibility in serviceability control of a building structure.
{"title":"Vibration isolation performance of quasi constant natural frequency isolation pads associated with test verification","authors":"Quanwu Zhang , Weixing Shi , Yuting Ouyang","doi":"10.1016/j.engstruct.2024.119328","DOIUrl":"10.1016/j.engstruct.2024.119328","url":null,"abstract":"<div><div>The vibration and noise induced by the operation of subway trains cause disturbances to the adjacent building structures. The serviceability of building structures (i.e., offices and residences) in terms of the annoyance of humans is sensitive to vibration and noise; therefore, it is necessary to conduct an effective vibration control strategy for building structures in terms of the structure-born noise and vibration protection. In serviceability-related vibration control, two issues are considered herein: (a) the irregularity of the controlled structure and (b) the structure uncertainties, such as insufficient knowledge about the structural mass redistributed in the isolation system. A quasi-constant natural frequency (QCNF) pad, mixed with rubber and foam material, is introduced herein to tackle these two issues. Such a system is nonlinear, and its stiffness is associated with the structural mass distribution. In this paper, a single-degree-of-freedom (SDOF) system is employed first to illustrate the property of a QCNF system. Inspired by the ideal load-displacement property of a QCNF system, a streamlined rubber element, an unconstrained cylinder rubber element, and two constrained cylinder rubber elements (including rigidly constrained and flexibly constrained) are designed and simulated with a finite element model. The physical properties of such four designed elements are obtained based on a static testing and an ambient field test. In the end, a quasi-constant frequency isolation pad mixed with rubber and foam material has been comprehensively discussed regarding the finite element simulation and an on-site ground-borne vibration test validation. The results indicate that the flexibly constrained QCNF rubber pad, using a combination of rubber and foam materials, can maintain a nearly constant frequency in the range of 67–1000 kPa load. The test validation based on a real-world application of the QCNF rubber pad indicates its feasibility in serviceability control of a building structure.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"324 ","pages":"Article 119328"},"PeriodicalIF":5.6,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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