Pub Date : 2026-02-06DOI: 10.1016/j.engstruct.2026.122276
Shaowei Hu , Jinghao Li , Qingbin Li , Yuquan Hu , Yahong Zhao , Yaoqun Xu
The failure and stability of high arch dams under coupled actions of thermal-humidity-chemical conditions is an important research issue. The scaled model test is reliable to reveal the failure process and stability of arch dam, whilst 3D-DIC is a powerful tool to synchronously visualize and quantify the full-field deformation and micro-cracks. The synergistic work of these two methods is anticipated to solve the failure process and mechanism of high arch dam under environmental acts. Therefore, the artificial simulated environment (ASE) of the dam site was designed by the theory of micro-environment response in concrete. The overloading tests were carried out on the arch dam models treated by 0, 150 and 300 cycles of ASE. The failure modes and mechanism of high arch dam under environmental actions were elaborated by the visualized cracks results and quantified analysis of arch-ring interaction based on full field-deformation of 3D-DIC. The stability safety factors for the crack initiation, the nonlinear deformation (including prominent arching action), and the ultimate bearing capacity were identified. A theoretical model of ultimate bearing capacity for high arch dams under coupled environmental acts was proposed and validated. This study is valuable for the long-term safety of high arch dams under actual environmental actions.
{"title":"Insights into impact of coupled environmental acts on failure and stability of high arch dams: Scaled model test and 3D-DIC-based visualized full-field deformation","authors":"Shaowei Hu , Jinghao Li , Qingbin Li , Yuquan Hu , Yahong Zhao , Yaoqun Xu","doi":"10.1016/j.engstruct.2026.122276","DOIUrl":"10.1016/j.engstruct.2026.122276","url":null,"abstract":"<div><div>The failure and stability of high arch dams under coupled actions of thermal-humidity-chemical conditions is an important research issue. The scaled model test is reliable to reveal the failure process and stability of arch dam, whilst 3D-DIC is a powerful tool to synchronously visualize and quantify the full-field deformation and micro-cracks. The synergistic work of these two methods is anticipated to solve the failure process and mechanism of high arch dam under environmental acts. Therefore, the artificial simulated environment (ASE) of the dam site was designed by the theory of micro-environment response in concrete. The overloading tests were carried out on the arch dam models treated by 0, 150 and 300 cycles of ASE. The failure modes and mechanism of high arch dam under environmental actions were elaborated by the visualized cracks results and quantified analysis of arch-ring interaction based on full field-deformation of 3D-DIC. The stability safety factors for the crack initiation, the nonlinear deformation (including prominent arching action), and the ultimate bearing capacity were identified. A theoretical model of ultimate bearing capacity for high arch dams under coupled environmental acts was proposed and validated. This study is valuable for the long-term safety of high arch dams under actual environmental actions.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122276"},"PeriodicalIF":6.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184790","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 : 2026-02-06DOI: 10.1016/j.engstruct.2026.122263
Zeqi Chen , Ying Gao , Yingsong Li , Zhuoran Li , Ziyue Zhou , Xiaoming Huang , Shunfeng Zhang , Kai Zhao , Wei Guo , Jing Guo
In structural seismic assessment, the selection of appropriate ground motions (GMs) is critical for obtaining reliable analytical results. This study proposes a novel evolutionary framework, EvoExtinction, for automated GM selection adaptable to various optimization scenarios. The framework integrates a refined genetic encoding scheme based on spectral characteristics, a two-stage evolutionary strategy, and a mass extinction mechanism to improve the global search capability and avoid local optima. During preprocessing, constraints are applied to GM parameters to preselect GMs that meet the specified criteria. For single-objective optimization, EvoExtinction enhances the classical Genetic Algorithm (GA), yielding SeismicGA, which improves spectral compatibility by minimizing the root-mean-square error (RMSE) between the average response spectrum of the selected GMs and the target spectrum. For multi-objective optimization, EvoExtinction is integrated into the Non-dominated Sorting Genetic Algorithm II (NSGA-II), producing Seismic-NSGA-II. It enables simultaneous optimization of spectral compatibility, scaling factors, and other GM parameters, including moment magnitude, epicentral distance, and shear wave velocity. Additionally, a target achievement rate (TAR) metric is introduced to evaluate the quality and stability of Pareto-optimal solutions under varying threshold conditions. The proposed framework generates diverse, high-quality GM subsets that meet compatibility thresholds while maintaining target parameter proximity. Its adaptability and robustness support practical implementation in seismic design workflows. In summary, EvoExtinction delivers a versatile, high-performance approach for GM selection and holds promise as a practical tool for seismic analysis in both research and engineering practice.
在结构地震评估中，选择合适的地震动是获得可靠分析结果的关键。本研究提出了一种新的进化框架——EvoExtinction，用于适应各种优化场景的自动转基因选择。该框架结合了基于谱特征的精细遗传编码方案、两阶段进化策略和大规模灭绝机制，提高了全局搜索能力，避免了局部最优。在预处理过程中，对GM参数施加约束，以预先选择符合指定条件的GM。对于单目标优化，EvoExtinction增强了经典遗传算法（GA），产生了SeismicGA，该算法通过最小化所选gm的平均响应谱与目标谱之间的均方根误差（RMSE）来提高光谱兼容性。为了进行多目标优化，将EvoExtinction集成到non - dominant Sorting Genetic Algorithm II （NSGA-II）中，得到Seismic-NSGA-II。它可以同时优化光谱兼容性、比例因子和其他GM参数，包括矩量级、震中距离和横波速度。此外，引入目标完成率（TAR）指标来评价不同阈值条件下pareto最优解的质量和稳定性。提出的框架生成多样化、高质量的GM子集，满足兼容性阈值，同时保持目标参数的接近性。它的适应性和鲁棒性支持在抗震设计工作流程中的实际实现。总之，EvoExtinction提供了一种多功能、高性能的转基因选择方法，有望成为研究和工程实践中地震分析的实用工具。
{"title":"EvoExtinction: A novel evolutionary framework for seismic ground motion selection applicable to various optimization scenarios","authors":"Zeqi Chen , Ying Gao , Yingsong Li , Zhuoran Li , Ziyue Zhou , Xiaoming Huang , Shunfeng Zhang , Kai Zhao , Wei Guo , Jing Guo","doi":"10.1016/j.engstruct.2026.122263","DOIUrl":"10.1016/j.engstruct.2026.122263","url":null,"abstract":"<div><div>In structural seismic assessment, the selection of appropriate ground motions (GMs) is critical for obtaining reliable analytical results. This study proposes a novel evolutionary framework, EvoExtinction, for automated GM selection adaptable to various optimization scenarios. The framework integrates a refined genetic encoding scheme based on spectral characteristics, a two-stage evolutionary strategy, and a mass extinction mechanism to improve the global search capability and avoid local optima. During preprocessing, constraints are applied to GM parameters to preselect GMs that meet the specified criteria. For single-objective optimization, EvoExtinction enhances the classical Genetic Algorithm (GA), yielding SeismicGA, which improves spectral compatibility by minimizing the root-mean-square error (<em>RMSE</em>) between the average response spectrum of the selected GMs and the target spectrum. For multi-objective optimization, EvoExtinction is integrated into the Non-dominated Sorting Genetic Algorithm II (NSGA-II), producing Seismic-NSGA-II. It enables simultaneous optimization of spectral compatibility, scaling factors, and other GM parameters, including moment magnitude, epicentral distance, and shear wave velocity. Additionally, a target achievement rate (TAR) metric is introduced to evaluate the quality and stability of Pareto-optimal solutions under varying threshold conditions. The proposed framework generates diverse, high-quality GM subsets that meet compatibility thresholds while maintaining target parameter proximity. Its adaptability and robustness support practical implementation in seismic design workflows. In summary, EvoExtinction delivers a versatile, high-performance approach for GM selection and holds promise as a practical tool for seismic analysis in both research and engineering practice.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122263"},"PeriodicalIF":6.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184869","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 : 2026-02-06DOI: 10.1016/j.engstruct.2026.122305
Zhuang Zhao , Yang Wei , Zihan Gong , Yi Ding , Yangtao Li
To investigate the seismic strength and performance of ultrahigh-performance concrete (UHPC)-filled stainless-steel tubular (UHPCFSST) columns, this study designed circular and square UHPCFSSTs seismic specimens. The seismic performance tests were carried out under constant axial load combined with cyclic lateral loading. The fundamental mechanical behaviors, including the failure mode in the plastic hinge region and the hysteresis curves of lateral load-displacement, were observed. A detailed parametric analysis was conducted on the stiffness degradation, energy dissipation capacity, displacement ductility, and strain in the plastic hinge region of the UHPCFSSTs. Based on the tested data and the development of models for key parameters such as peak load, a highly accurate skeleton curve model for UHPCFSSTs was established. On the basis of determining hysteresis rules for the lateral load-displacement curves, a unified hysteretic model for circular and square UHPCFSSTs was systematically developed. The proposed hysteretic model demonstrates high predictive accuracy and can efficiently simulate the lateral load-displacement hysteresis curves of UHPCFSSTs.
{"title":"Seismic performance of circular and square UHPC-filled stainless-steel tubular columns","authors":"Zhuang Zhao , Yang Wei , Zihan Gong , Yi Ding , Yangtao Li","doi":"10.1016/j.engstruct.2026.122305","DOIUrl":"10.1016/j.engstruct.2026.122305","url":null,"abstract":"<div><div>To investigate the seismic strength and performance of ultrahigh-performance concrete (UHPC)-filled stainless-steel tubular (UHPCFSST) columns, this study designed circular and square UHPCFSSTs seismic specimens. The seismic performance tests were carried out under constant axial load combined with cyclic lateral loading. The fundamental mechanical behaviors, including the failure mode in the plastic hinge region and the hysteresis curves of lateral load-displacement, were observed. A detailed parametric analysis was conducted on the stiffness degradation, energy dissipation capacity, displacement ductility, and strain in the plastic hinge region of the UHPCFSSTs. Based on the tested data and the development of models for key parameters such as peak load, a highly accurate skeleton curve model for UHPCFSSTs was established. On the basis of determining hysteresis rules for the lateral load-displacement curves, a unified hysteretic model for circular and square UHPCFSSTs was systematically developed. The proposed hysteretic model demonstrates high predictive accuracy and can efficiently simulate the lateral load-displacement hysteresis curves of UHPCFSSTs.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122305"},"PeriodicalIF":6.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184870","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 : 2026-02-06DOI: 10.1016/j.engstruct.2026.122266
Mostafa H. Shoaib , Xin Wang , Mohamed R. Abdellatif , Shui Liu , Zhishen Wu , Amr M.A. Moussa
This study experimentally investigates the shear performance and serviceability of concrete beams reinforced with a new hybrid stirrup system combining inner steel and outer fiber-reinforced polymer (FRP) stirrups. The proposed configuration aims to improve structural ductility and corrosion protection in aggressive environments. A total of eleven full-scale simply supported beams were tested under four-point bending. These beams were divided into four groups to separately evaluate the influence of stirrup material type, steel-to-FRP area ratio, spacing, and configuration (including conventional ties, spirals, and alternating arrangements). Test results demonstrated that hybrid stirrups enhanced both shear capacity and ductility while offering effective crack control. At matched stirrup axial stiffness, hybrid stirrup-reinforced beams achieved enhancements of up to 36.4 % in shear capacity, 30.3 % in displacement ductility index, and 47.4 % in service load compared to those with conventional steel stirrups. A steel-to-FRP area ratio of 1.0 with reduced stirrup spacing provided a balanced performance in terms of strength and crack control. Spiral stirrups further improved confinement, resulting in 21.8 % higher displacement ductility index compared to closed-tie alternatives. The findings suggest that the proposed hybrid stirrup system is a promising shear reinforcement technique for enhancing the shear performance of concrete beams.
{"title":"Experimental study on shear behavior and serviceability of concrete beams reinforced with hybrid steel-FRP stirrups","authors":"Mostafa H. Shoaib , Xin Wang , Mohamed R. Abdellatif , Shui Liu , Zhishen Wu , Amr M.A. Moussa","doi":"10.1016/j.engstruct.2026.122266","DOIUrl":"10.1016/j.engstruct.2026.122266","url":null,"abstract":"<div><div>This study experimentally investigates the shear performance and serviceability of concrete beams reinforced with a new hybrid stirrup system combining inner steel and outer fiber-reinforced polymer (FRP) stirrups. The proposed configuration aims to improve structural ductility and corrosion protection in aggressive environments. A total of eleven full-scale simply supported beams were tested under four-point bending. These beams were divided into four groups to separately evaluate the influence of stirrup material type, steel-to-FRP area ratio, spacing, and configuration (including conventional ties, spirals, and alternating arrangements). Test results demonstrated that hybrid stirrups enhanced both shear capacity and ductility while offering effective crack control. At matched stirrup axial stiffness, hybrid stirrup-reinforced beams achieved enhancements of up to 36.4 % in shear capacity, 30.3 % in displacement ductility index, and 47.4 % in service load compared to those with conventional steel stirrups. A steel-to-FRP area ratio of 1.0 with reduced stirrup spacing provided a balanced performance in terms of strength and crack control. Spiral stirrups further improved confinement, resulting in 21.8 % higher displacement ductility index compared to closed-tie alternatives. The findings suggest that the proposed hybrid stirrup system is a promising shear reinforcement technique for enhancing the shear performance of concrete beams.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122266"},"PeriodicalIF":6.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184792","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}
Spectral shape is one of the most influential ground motion characteristics affecting seismic performance assessment. When performing dynamic analysis using a generic record set, spectral shape is typically accounted for by adjusting results through a spectral shape indicator to ensure hazard consistency. One effective indicator is , defined as the ratio of spectral acceleration at the fundamental period to the geometric mean over a specified range. While prior studies have shown that correlates strongly with collapse intensity, its predictive accuracy depends heavily on the chosen period range, and its applicability to non-collapse performance levels, particularly those based on component-level criteria, has not been systematically investigated. This study improves the use of for spectral shape adjustment across multiple performance levels. A database of 75 code-compliant RC moment frames, representing a wide range of structural properties, was analyzed using shallow crustal and subduction ground motions. Optimal period ranges were proposed to strengthen the correlation between and performance intensities. Results showed that period ranges suitable for collapse prediction in ductile buildings may not apply to limited-ductility structures or non-collapse levels. The proposed period ranges yielded the most stable safety margins across various ground motion sets. Monte Carlo simulations further demonstrated that using the proposed period ranges reduces the sensitivity of median performance predictions to record sample size and yields more consistent local damage estimates.
{"title":"Optimal period range selection for site-specific spectral shape adjustment in RC moment frames considering component-level performance criteria","authors":"Mohammadreza Salek Faramarzi , Vahid Sadeghian , Farrokh Fazileh , Reza Fathi-Fazl","doi":"10.1016/j.engstruct.2026.122277","DOIUrl":"10.1016/j.engstruct.2026.122277","url":null,"abstract":"<div><div>Spectral shape is one of the most influential ground motion characteristics affecting seismic performance assessment. When performing dynamic analysis using a generic record set, spectral shape is typically accounted for by adjusting results through a spectral shape indicator to ensure hazard consistency. One effective indicator is <span><math><mi>SaRatio</mi></math></span>, defined as the ratio of spectral acceleration at the fundamental period to the geometric mean over a specified range. While prior studies have shown that <span><math><mi>SaRatio</mi></math></span> correlates strongly with collapse intensity, its predictive accuracy depends heavily on the chosen period range, and its applicability to non-collapse performance levels, particularly those based on component-level criteria, has not been systematically investigated. This study improves the use of <span><math><mi>SaRatio</mi></math></span> for spectral shape adjustment across multiple performance levels. A database of 75 code-compliant RC moment frames, representing a wide range of structural properties, was analyzed using shallow crustal and subduction ground motions. Optimal period ranges were proposed to strengthen the correlation between <span><math><mi>SaRatio</mi></math></span> and performance intensities. Results showed that period ranges suitable for collapse prediction in ductile buildings may not apply to limited-ductility structures or non-collapse levels. The proposed period ranges yielded the most stable safety margins across various ground motion sets. Monte Carlo simulations further demonstrated that using the proposed period ranges reduces the sensitivity of median performance predictions to record sample size and yields more consistent local damage estimates.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122277"},"PeriodicalIF":6.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184798","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 : 2026-02-06DOI: 10.1016/j.engstruct.2026.122309
Shifeng Liu , Xiang Hong , Kunkun Fu , Zhongsen Zhang , Yan Li
3D-printed continuous carbon fiber-reinforced composites (CCFRCs) are widely utilized for their superior design flexibility and mechanical properties in aerospace and civil engineering. Topology optimization enables further weight reduction of 3D-printed structures. Current topology optimization methods for continuous fiber-reinforced composites primarily focus on minimizing compliance under a maximum volume constraint. However, such optimizations often produce slender regions that are susceptible to buckling failure. This study proposes a topology optimization approach for 3D-printed continuous fiber-reinforced composites that incorporates both maximum volume and minimum buckling strength constraints, enabling the simultaneous optimization of structural topology and fiber orientation. A buckling-constrained solid orthotropic material with penalization (BCSOMP) method is proposed for material parameterization. The Kreisselmeier–Steinhauser (KS) aggregation function is employed to combine multiple buckling constraints into a single differentiable constraint. Numerical studies on cantilever, L-shaped beam, and bending beam validate the proposed method. Additionally, carbon fiber-reinforced composite beam structures, both with and without buckling constraints, are fabricated and subjected to bending tests. The experimental results demonstrate that incorporating buckling constraint into topology optimization slightly reduces structural stiffness but significantly enhances buckling strength, confirming the method’s effectiveness in improving buckling resistance.
{"title":"Topology optimization of 3D-printed continuous fiber-reinforced composites considering buckling constraint","authors":"Shifeng Liu , Xiang Hong , Kunkun Fu , Zhongsen Zhang , Yan Li","doi":"10.1016/j.engstruct.2026.122309","DOIUrl":"10.1016/j.engstruct.2026.122309","url":null,"abstract":"<div><div>3D-printed continuous carbon fiber-reinforced composites (CCFRCs) are widely utilized for their superior design flexibility and mechanical properties in aerospace and civil engineering. Topology optimization enables further weight reduction of 3D-printed structures. Current topology optimization methods for continuous fiber-reinforced composites primarily focus on minimizing compliance under a maximum volume constraint. However, such optimizations often produce slender regions that are susceptible to buckling failure. This study proposes a topology optimization approach for 3D-printed continuous fiber-reinforced composites that incorporates both maximum volume and minimum buckling strength constraints, enabling the simultaneous optimization of structural topology and fiber orientation. A buckling-constrained solid orthotropic material with penalization (BCSOMP) method is proposed for material parameterization. The Kreisselmeier–Steinhauser (KS) aggregation function is employed to combine multiple buckling constraints into a single differentiable constraint. Numerical studies on cantilever, <span>L</span>-shaped beam, and bending beam validate the proposed method. Additionally, carbon fiber-reinforced composite beam structures, both with and without buckling constraints, are fabricated and subjected to bending tests. The experimental results demonstrate that incorporating buckling constraint into topology optimization slightly reduces structural stiffness but significantly enhances buckling strength, confirming the method’s effectiveness in improving buckling resistance.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122309"},"PeriodicalIF":6.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184867","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 : 2026-02-05DOI: 10.1016/j.engstruct.2026.122270
Amir Hossein Asjodi
This paper employs supervised and unsupervised learning methods to present hazard-based seismic fragility functions for Steel Moment-Resisting Frame (SMRF) buildings. The database supporting this research comprises structural responses of over 12,000 time history analyses for 100 SMRF buildings lumped into three categories: low-, mid-, and high-rise. The ground motions have been selected to represent three hazard levels, resulting in Service Level Earthquake (SLE), Design Basis Earthquake (DBE), and Maximum Considered Earthquake (MCE). Considering the primary period of each building and the target response spectra, a set of ground motions is selected, and the peak story drift ratios are extracted. Subsequently, unsupervised clustering techniques are employed to identify drift thresholds that distinguish between different damage states across various hazard levels, thereby refining the fixed boundaries recommended in existing codes and guidelines. Supervised learning techniques, on the other hand, are employed to predict the maximum drift ratio using features from ground motions and structural periods. The resulting drift ratio serves as an Engineering Demand Parameter (EDP), which, along with the hazard-informed drift threshold, is used to generate a machine learning-based fragility function. The proposed approach enables damage state identification of SMRF buildings under a specific ground motion, using only structural periods and signal features, without requiring detailed structural response data. The results of this study provide a set of site-specific hazard-based fragility curves, supporting seismic risk and loss assessment across different earthquake intensities.
{"title":"Hazard-based seismic fragility functions for steel moment-resisting frame buildings through data-driven damage state identification","authors":"Amir Hossein Asjodi","doi":"10.1016/j.engstruct.2026.122270","DOIUrl":"10.1016/j.engstruct.2026.122270","url":null,"abstract":"<div><div>This paper employs supervised and unsupervised learning methods to present hazard-based seismic fragility functions for Steel Moment-Resisting Frame (SMRF) buildings. The database supporting this research comprises structural responses of over 12,000 time history analyses for 100 SMRF buildings lumped into three categories: low-, mid-, and high-rise. The ground motions have been selected to represent three hazard levels, resulting in Service Level Earthquake (SLE), Design Basis Earthquake (DBE), and Maximum Considered Earthquake (MCE). Considering the primary period of each building and the target response spectra, a set of ground motions is selected, and the peak story drift ratios are extracted. Subsequently, unsupervised clustering techniques are employed to identify drift thresholds that distinguish between different damage states across various hazard levels, thereby refining the fixed boundaries recommended in existing codes and guidelines. Supervised learning techniques, on the other hand, are employed to predict the maximum drift ratio using features from ground motions and structural periods. The resulting drift ratio serves as an Engineering Demand Parameter (EDP), which, along with the hazard-informed drift threshold, is used to generate a machine learning-based fragility function. The proposed approach enables damage state identification of SMRF buildings under a specific ground motion, using only structural periods and signal features, without requiring detailed structural response data. The results of this study provide a set of site-specific hazard-based fragility curves, supporting seismic risk and loss assessment across different earthquake intensities.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122270"},"PeriodicalIF":6.4,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116372","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}
Flexible modes with low damping limit the improvement of performance in nanometer precision motion stages. Tuned mass dampers (TMDs) are an effective devices to increase damping. However, active control strategies considering both the TMDs parameter optimization and system robustness have not been sufficiently explored. This paper proposes an active multi-TMD system optimization method for resonance suppression applied to a flexible structure. In the multi-TMD system, the mass, damping coefficient, stiffness, and location of each TMD are all regarded as independent design variables. The flexible structure coupled with the multi-TMD system is modeled as a general Linear Fractional Transformation (LFT) framework considering both parameter uncertainties and multiplicative uncertainties in the two subsystems. Optimal parameters of the multi-TMD system and an optimal controller are obtained simultaneously using genetic algorithm. With the structured singular value upper bound constraint, robust stability against uncertainties is guaranteed. Numerical studies on a thin plate demonstrate the superiority of the proposed method in both nominal and uncertain systems. Among 5000 samples, the proposed method achieves more than 82% norm attenuation even in the worst case.
{"title":"H2 norm based active multiple tuned mass dampers optimization for resonance suppression with robust stability constraint","authors":"Jianqiang Yao, Haode Huo, Yunzhi Zhang, Qin Li, Wentao Li, Chenyang Ding","doi":"10.1016/j.engstruct.2026.122316","DOIUrl":"10.1016/j.engstruct.2026.122316","url":null,"abstract":"<div><div>Flexible modes with low damping limit the improvement of performance in nanometer precision motion stages. Tuned mass dampers (TMDs) are an effective devices to increase damping. However, active control strategies considering both the TMDs parameter optimization and system robustness have not been sufficiently explored. This paper proposes an active multi-TMD system optimization method for resonance suppression applied to a flexible structure. In the multi-TMD system, the mass, damping coefficient, stiffness, and location of each TMD are all regarded as independent design variables. The flexible structure coupled with the multi-TMD system is modeled as a general Linear Fractional Transformation (LFT) framework considering both parameter uncertainties and multiplicative uncertainties in the two subsystems. Optimal parameters of the multi-TMD system and an optimal <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> controller are obtained simultaneously using genetic algorithm. With the structured singular value upper bound constraint, robust stability against uncertainties is guaranteed. Numerical studies on a thin plate demonstrate the superiority of the proposed method in both nominal and uncertain systems. Among 5000 samples, the proposed method achieves more than 82% <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> norm attenuation even in the worst case.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122316"},"PeriodicalIF":6.4,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185392","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 : 2026-02-05DOI: 10.1016/j.engstruct.2026.122278
Sasa Cao , Xiaolong Sheng , Haojie Qiu , Osman E. Ozbulut
Conventional friction pendulum isolators rely on fixed spherical surfaces or discrete sliding stages, which constrain their ability to provide smooth stiffness adaptation and limit their frictional energy dissipation. To address these limitations, this study investigates a novel gravity-well double friction pendulum system (GW-DFPS) that employs a variable-curvature sliding surface to elongate displacement trajectories and enhance energy dissipation while enabling continuous stiffness softening at large displacements. Through a series of shake table experiments, a scaled bridge superstructure isolated with GW-DFPS was subjected to a range of uni- and bi-directional ground motions representing different site conditions and seismic intensities. Experimental results confirm that the system exhibits the intended softening behavior at larger displacements, effectively limiting force demands while accommodating significant lateral motions. Comparisons between unidirectional and bidirectional excitations highlight that the latter can lead to increased displacement demands, though with moderated acceleration responses. Residual displacements were small across all tests. Energy-based evaluations revealed a clear trade-off between kinetic and gravitational potential energy, with frictional dissipation increasing with sliding velocity. Overall, the GW-DFPS demonstrates strong potential as a next-generation seismic isolation device capable of sustaining large displacements while reducing shear forces transmitted to the superstructure.
{"title":"Shake table tests of gravity well-inspired double friction pendulum systems under Bi-directional ground motions","authors":"Sasa Cao , Xiaolong Sheng , Haojie Qiu , Osman E. Ozbulut","doi":"10.1016/j.engstruct.2026.122278","DOIUrl":"10.1016/j.engstruct.2026.122278","url":null,"abstract":"<div><div>Conventional friction pendulum isolators rely on fixed spherical surfaces or discrete sliding stages, which constrain their ability to provide smooth stiffness adaptation and limit their frictional energy dissipation. To address these limitations, this study investigates a novel gravity-well double friction pendulum system (GW-DFPS) that employs a variable-curvature sliding surface to elongate displacement trajectories and enhance energy dissipation while enabling continuous stiffness softening at large displacements. Through a series of shake table experiments, a scaled bridge superstructure isolated with GW-DFPS was subjected to a range of uni- and bi-directional ground motions representing different site conditions and seismic intensities. Experimental results confirm that the system exhibits the intended softening behavior at larger displacements, effectively limiting force demands while accommodating significant lateral motions. Comparisons between unidirectional and bidirectional excitations highlight that the latter can lead to increased displacement demands, though with moderated acceleration responses. Residual displacements were small across all tests. Energy-based evaluations revealed a clear trade-off between kinetic and gravitational potential energy, with frictional dissipation increasing with sliding velocity. Overall, the GW-DFPS demonstrates strong potential as a next-generation seismic isolation device capable of sustaining large displacements while reducing shear forces transmitted to the superstructure.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122278"},"PeriodicalIF":6.4,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116371","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 : 2026-02-05DOI: 10.1016/j.engstruct.2026.122224
Jun Xie , Hui Li , Yongqiang Ye , WenShuai Wang , Xiaofan Gou , Pengpeng Shi
Recent advances in artificial intelligence have established physics-informed neural networks (PINNs) as a transformative paradigm for solving complex mechanics problems. This paper presents a unified PINN framework that comprehensively addresses three fundamental problems in functionally graded materials (FGMs) cylinder analysis: forward prediction, inverse identification, and stress optimization. The proposed methodology embeds physical laws including constitutive relations and equilibrium equations into a deep learning architecture, yielding a meshless solution with rigorous mechanical consistency. For forward problems, the framework accurately predicts displacement and stress fields under arbitrary material gradations. The inverse solution enables simultaneous identification of gradient parameters and Young's modulus with high precision. For optimization challenges, the architecture introduces coupled displacement-material networks with exact boundary condition enforcement and a multi-objective loss function that achieves stress minimization while maintaining mechanical equilibrium. Numerical results demonstrate three key capabilities: (1) PINN achieves excellent agreement with reference solutions in forward analysis of FGMs cylinders arbitrarily varying material properties, (2) the inverse problem yields accurate identification of both the gradient parameter and the varying Young’s modulus, even under measurement noise, and (3) the optimization problem outperforms conventional power-law distributions by reducing peak von Mises stress while preserving exact mechanical consistency. The integrated framework combines the computational efficiency of parametric methods with the design freedom of free-form optimization, offering an end-to-end solution from problem formulation to sensitivity analysis. This research establishes PINNs as a versatile tool for FGMs design, providing both theoretical foundations and practical methodologies for engineering applications ranging from mechanical analysis to optimal material design.
{"title":"Physics-informed neural networks framework for functionally graded cylinder: Forward analysis, inverse material identification, and stress-driven optimization","authors":"Jun Xie , Hui Li , Yongqiang Ye , WenShuai Wang , Xiaofan Gou , Pengpeng Shi","doi":"10.1016/j.engstruct.2026.122224","DOIUrl":"10.1016/j.engstruct.2026.122224","url":null,"abstract":"<div><div>Recent advances in artificial intelligence have established physics-informed neural networks (PINNs) as a transformative paradigm for solving complex mechanics problems. This paper presents a unified PINN framework that comprehensively addresses three fundamental problems in functionally graded materials (FGMs) cylinder analysis: forward prediction, inverse identification, and stress optimization. The proposed methodology embeds physical laws including constitutive relations and equilibrium equations into a deep learning architecture, yielding a meshless solution with rigorous mechanical consistency. For forward problems, the framework accurately predicts displacement and stress fields under arbitrary material gradations. The inverse solution enables simultaneous identification of gradient parameters and Young's modulus with high precision. For optimization challenges, the architecture introduces coupled displacement-material networks with exact boundary condition enforcement and a multi-objective loss function that achieves stress minimization while maintaining mechanical equilibrium. Numerical results demonstrate three key capabilities: (1) PINN achieves excellent agreement with reference solutions in forward analysis of FGMs cylinders arbitrarily varying material properties, (2) the inverse problem yields accurate identification of both the gradient parameter and the varying Young’s modulus, even under measurement noise, and (3) the optimization problem outperforms conventional power-law distributions by reducing peak von Mises stress while preserving exact mechanical consistency. The integrated framework combines the computational efficiency of parametric methods with the design freedom of free-form optimization, offering an end-to-end solution from problem formulation to sensitivity analysis. This research establishes PINNs as a versatile tool for FGMs design, providing both theoretical foundations and practical methodologies for engineering applications ranging from mechanical analysis to optimal material design.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122224"},"PeriodicalIF":6.4,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184863","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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