Pub Date : 2026-02-05DOI: 10.1016/j.istruc.2026.111232
Jianghao Yuan , Chengrong Huang , Qiang Zhang
Ultra-high performance concrete (UHPC) is widely used for structural strengthening and repair due to its high strength and excellent durability. The interface between UHPC and normal strength concrete (NSC) often represents a structural weakness. To improve the interface shear capacity, reinforcement planting is commonly adopted due to its ease of construction and low cost. However, the addition of reinforcement planting complicates the interfacial mechanics between UHPC and NSC. In this work, an enhanced approach was developed to compute the shear capacity at the UHPC-NSC interface with reinforcement planting. A database of 132 UHPC–NSC reinforcement planting shear tests was collected from available published literature. To solve the limited test data issue, a data augmentation model was introduced, and GAN-based augmentation model was employed. Four machine learning methods were systematically discussed. Based on gene expression programming, a simplified prediction model was also proposed. The results demonstrate that this model can reproduce the shear performance of the UHPC-NSC interface with reinforcement planting. This approach offers a practical tool for assisting structural retrofitting design.
{"title":"An enhanced model for shear strength of UHPC–NSC interfaces considering reinforcement planting","authors":"Jianghao Yuan , Chengrong Huang , Qiang Zhang","doi":"10.1016/j.istruc.2026.111232","DOIUrl":"10.1016/j.istruc.2026.111232","url":null,"abstract":"<div><div>Ultra-high performance concrete (UHPC) is widely used for structural strengthening and repair due to its high strength and excellent durability. The interface between UHPC and normal strength concrete (NSC) often represents a structural weakness. To improve the interface shear capacity, reinforcement planting is commonly adopted due to its ease of construction and low cost. However, the addition of reinforcement planting complicates the interfacial mechanics between UHPC and NSC. In this work, an enhanced approach was developed to compute the shear capacity at the UHPC-NSC interface with reinforcement planting. A database of 132 UHPC–NSC reinforcement planting shear tests was collected from available published literature. To solve the limited test data issue, a data augmentation model was introduced, and GAN-based augmentation model was employed. Four machine learning methods were systematically discussed. Based on gene expression programming, a simplified prediction model was also proposed. The results demonstrate that this model can reproduce the shear performance of the UHPC-NSC interface with reinforcement planting. This approach offers a practical tool for assisting structural retrofitting design.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111232"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192574","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111206
Lin Yang , Ci-Rong Huang , Xu-Hong Zhou , Wei Ren , Yu-Hang Wang
The prestressed concrete wind towers have applications potential in lower wind velocity region. The calculation of the ultimate limit states of thin-walled concrete structures under combined loads has attracted widespread attention. In this paper, a series of works have been conducted on its combined compressive-flexural-shear-torsional behaviour. A test system was designed using a combined loading method and considering various types of damage. The results show that the composite failure modes can involve multiple failure phenomena occurring simultaneously. Increasing the reinforcement ratio can enhance the post-yield bearing capacity of the specimens but has little effect on their stiffness. Finally, based on the unified formula for the ultimate bearing capacity of reinforced concrete, two assumptions of the eccentric compression formula for circular ring sections were derived using the strut-and-tie model and compared with the test results. The results indicate that the method recommended by the code is generally conservative for many conditions but has higher coefficient of variability. In contrast, the improved method reduces computational variability by 28.8 % while maintaining safety, providing more consistent and reliable predictions. This indicates that the improved method exhibits higher applicability across various loading conditions. The improved method addresses the gaps in current codes for design under combined loading conditions, integrating the verification of individual loading states into a more effective verification approach.
{"title":"Static behavior of the prestressed concrete wind tower section under combined compression-bending-shear-torsion loading","authors":"Lin Yang , Ci-Rong Huang , Xu-Hong Zhou , Wei Ren , Yu-Hang Wang","doi":"10.1016/j.istruc.2026.111206","DOIUrl":"10.1016/j.istruc.2026.111206","url":null,"abstract":"<div><div>The prestressed concrete wind towers have applications potential in lower wind velocity region. The calculation of the ultimate limit states of thin-walled concrete structures under combined loads has attracted widespread attention. In this paper, a series of works have been conducted on its combined compressive-flexural-shear-torsional behaviour. A test system was designed using a combined loading method and considering various types of damage. The results show that the composite failure modes can involve multiple failure phenomena occurring simultaneously. Increasing the reinforcement ratio can enhance the post-yield bearing capacity of the specimens but has little effect on their stiffness. Finally, based on the unified formula for the ultimate bearing capacity of reinforced concrete, two assumptions of the eccentric compression formula for circular ring sections were derived using the strut-and-tie model and compared with the test results. The results indicate that the method recommended by the code is generally conservative for many conditions but has higher coefficient of variability. In contrast, the improved method reduces computational variability by 28.8 % while maintaining safety, providing more consistent and reliable predictions. This indicates that the improved method exhibits higher applicability across various loading conditions. The improved method addresses the gaps in current codes for design under combined loading conditions, integrating the verification of individual loading states into a more effective verification approach.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111206"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192128","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111289
Yi Ding , Yang Wei , Huiwen Tian , Linjie Huang , Kaiqi Zheng , Siyu Zhou
Ultra-high performance concrete (UHPC) is suitable for connecting precast shear walls because of its good bonding behavior with ordinary strength concrete and steel reinforcements. Based on the purpose of improving the seismic performance and construction efficiency of traditional precast concrete shear walls, a novel precast shear wall was proposed, which combined the local UHPC connection in the boundary element, the post-tensioned (PT) tendons and unconnected vertical distributed bars in the web region. Five shear walls, including four precast and one cast-in-place (CIP) shear walls, were subjected to quasi-static tests to analyze their hysteretic mechanism under the test variables of initial stress of PT tendons, height of post-cast UHPC and axial compression ratio. The damage degree of the precast shear wall was significantly lower than that of the CIP shear wall, and its residual drift decreased by 15 %-26 % at the lateral drift of 1 %-2.5 %, indicating that the precast shear wall had excellent post-earthquake repairability. Moreover, the precast shear walls could achieve the improvement in energy dissipation, ductility and peak load, especially in areas with high seismic intensities, with better application prospects. It proved that the proposed assembly method was effective and superior to cast-in-place construction. In addition, a method for calculating the peak load of UHPC composite shear walls was developed with an error of less than 6 %.
{"title":"Seismic performance of precast shear walls connected by post-tensioned tendons and UHPC in boundary elements","authors":"Yi Ding , Yang Wei , Huiwen Tian , Linjie Huang , Kaiqi Zheng , Siyu Zhou","doi":"10.1016/j.istruc.2026.111289","DOIUrl":"10.1016/j.istruc.2026.111289","url":null,"abstract":"<div><div>Ultra-high performance concrete (UHPC) is suitable for connecting precast shear walls because of its good bonding behavior with ordinary strength concrete and steel reinforcements. Based on the purpose of improving the seismic performance and construction efficiency of traditional precast concrete shear walls, a novel precast shear wall was proposed, which combined the local UHPC connection in the boundary element, the post-tensioned (PT) tendons and unconnected vertical distributed bars in the web region. Five shear walls, including four precast and one cast-in-place (CIP) shear walls, were subjected to quasi-static tests to analyze their hysteretic mechanism under the test variables of initial stress of PT tendons, height of post-cast UHPC and axial compression ratio. The damage degree of the precast shear wall was significantly lower than that of the CIP shear wall, and its residual drift decreased by 15 %-26 % at the lateral drift of 1 %-2.5 %, indicating that the precast shear wall had excellent post-earthquake repairability. Moreover, the precast shear walls could achieve the improvement in energy dissipation, ductility and peak load, especially in areas with high seismic intensities, with better application prospects. It proved that the proposed assembly method was effective and superior to cast-in-place construction. In addition, a method for calculating the peak load of UHPC composite shear walls was developed with an error of less than 6 %.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111289"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192133","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111288
Lu-Xi Li , Jin-Cheng Wu , Chao Li , Hong Hao
This paper investigates the hysteretic performance of a novel separately-anchored self-centering (SASC) frame system in which H-shaped steel beams are positioned between reinforced concrete beams and columns to provide independent anchorage for post-tensioned (PT) tendons in each bay. This innovative configuration eliminates the serial connection of beams across multiple spans in conventional post-tensioned self-centering (PTSC) frames. A comprehensive numerical analysis is conducted using validated finite element models to systematically evaluate the cyclic behavior of SASC frames with different configurations, including varying column base types (reinforced bases and post-tensioned bases), span numbers (single-bay and two-bay), and with or without friction dampers. The analysis specifically focuses on the expansion phenomenon unique to self-centering structures and provides comprehensive performance comparisons with traditional PTSC frames. Results reveal that SASC frames exhibit significant advantages in mechanical performance with enhanced strength and post-yield stiffness, while effectively mitigating damage to joint core regions. Column base type significantly influences structural behavior, with post-tensioned column bases demonstrating excellent damage avoidance and self-centering capabilities, whereas reinforced column bases provide substantial energy dissipation at the expense of compromised re-centering property and considerable column base damage. Furthermore, the frame expansion effect is quantitatively evaluated, showing SASC frames experience larger expansion deformations (20–25 % of story drift) than PTSC frames (approximately 15 %). Prestressing force variations correlate strongly with frame expansion patterns, and a prediction method for PT forces at different story drift levels is proposed. This study provides insights for implementing SASC frames as an innovative structural solution for enhancing seismic resilience in multi-span building applications.
{"title":"Seismic behavior of a new separately-anchored self-centering frame","authors":"Lu-Xi Li , Jin-Cheng Wu , Chao Li , Hong Hao","doi":"10.1016/j.istruc.2026.111288","DOIUrl":"10.1016/j.istruc.2026.111288","url":null,"abstract":"<div><div>This paper investigates the hysteretic performance of a novel separately-anchored self-centering (SASC) frame system in which H-shaped steel beams are positioned between reinforced concrete beams and columns to provide independent anchorage for post-tensioned (PT) tendons in each bay. This innovative configuration eliminates the serial connection of beams across multiple spans in conventional post-tensioned self-centering (PTSC) frames. A comprehensive numerical analysis is conducted using validated finite element models to systematically evaluate the cyclic behavior of SASC frames with different configurations, including varying column base types (reinforced bases and post-tensioned bases), span numbers (single-bay and two-bay), and with or without friction dampers. The analysis specifically focuses on the expansion phenomenon unique to self-centering structures and provides comprehensive performance comparisons with traditional PTSC frames. Results reveal that SASC frames exhibit significant advantages in mechanical performance with enhanced strength and post-yield stiffness, while effectively mitigating damage to joint core regions. Column base type significantly influences structural behavior, with post-tensioned column bases demonstrating excellent damage avoidance and self-centering capabilities, whereas reinforced column bases provide substantial energy dissipation at the expense of compromised re-centering property and considerable column base damage. Furthermore, the frame expansion effect is quantitatively evaluated, showing SASC frames experience larger expansion deformations (20–25 % of story drift) than PTSC frames (approximately 15 %). Prestressing force variations correlate strongly with frame expansion patterns, and a prediction method for PT forces at different story drift levels is proposed. This study provides insights for implementing SASC frames as an innovative structural solution for enhancing seismic resilience in multi-span building applications.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111288"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192134","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111274
Chien-Kuo Chiu , Fikri Ghifari , Budi Suswanto
The Fiber Concrete–Enhanced Steel (FCES) column is a composite column consisting only of a steel section and fiber-reinforced concrete, without conventional reinforcement, thereby reducing construction complexity. Currently, ASCE 41 does not provide modeling parameters for FCES columns. In addition, the AIJ guidelines propose a mechanical model for FCES columns based on the assumption of a flexural failure mode. However, this model does not reflect the actual behavior observed in many experimentally tested FCES columns reported in previous studies, where the predominant failure mode is flexural–shear. This study develops a nonlinear mechanical model for FCES columns exhibiting flexural–shear failure. The proposed model is modified from an existing Steel-Reinforced Concrete (SRC) model and is validated using 25 FCES column test datasets. The model is applicable to concrete compressive strengths ranging from 31.2 to 65.3 MPa, axial load ratios of 0.09–0.30, fiber contents of 1–2 %, XH-steel ratios of 5.64–6.65 %, and H-steel ratios of 3–7.01 %. The considered fiber types include Hybrid fiber concrete (HyFC), Steel fiber concrete (SFC), and PVA fiber concrete (PVA-FC). Three fiber concrete material properties—compressive strength, flexural strength, and elastic modulus—are examined. For HyFC, regression formulas are developed to predict compressive and flexural strengths with average errors of 8.4 % and 14.8 %, respectively, while the elastic modulus is estimated using an existing empirical relation due to limited available data. For SFC and PVA-FC, existing predictive formulas are evaluated and the most reliable are adopted. The proposed model defines four key points—cracking, peak, stable post-peak, and ultimate—based on elastic analysis, P–M interaction, and modified deformation relationships. The results demonstrate conservative predictive performance. Nevertheless, further studies are required to extend the applicability of the model to higher axial load ratios, broader steel section ratios, and more reliable elastic modulus models for HyFC.
{"title":"Development and validation of a nonlinear mechanical model for fiber concrete-enhanced steel columns with flexural-shear failure mode","authors":"Chien-Kuo Chiu , Fikri Ghifari , Budi Suswanto","doi":"10.1016/j.istruc.2026.111274","DOIUrl":"10.1016/j.istruc.2026.111274","url":null,"abstract":"<div><div>The Fiber Concrete–Enhanced Steel (FCES) column is a composite column consisting only of a steel section and fiber-reinforced concrete, without conventional reinforcement, thereby reducing construction complexity. Currently, ASCE 41 does not provide modeling parameters for FCES columns. In addition, the AIJ guidelines propose a mechanical model for FCES columns based on the assumption of a flexural failure mode. However, this model does not reflect the actual behavior observed in many experimentally tested FCES columns reported in previous studies, where the predominant failure mode is flexural–shear. This study develops a nonlinear mechanical model for FCES columns exhibiting flexural–shear failure. The proposed model is modified from an existing Steel-Reinforced Concrete (SRC) model and is validated using 25 FCES column test datasets. The model is applicable to concrete compressive strengths ranging from 31.2 to 65.3 MPa, axial load ratios of 0.09–0.30, fiber contents of 1–2 %, XH-steel ratios of 5.64–6.65 %, and H-steel ratios of 3–7.01 %. The considered fiber types include Hybrid fiber concrete (HyFC), Steel fiber concrete (SFC), and PVA fiber concrete (PVA-FC). Three fiber concrete material properties—compressive strength, flexural strength, and elastic modulus—are examined. For HyFC, regression formulas are developed to predict compressive and flexural strengths with average errors of 8.4 % and 14.8 %, respectively, while the elastic modulus is estimated using an existing empirical relation due to limited available data. For SFC and PVA-FC, existing predictive formulas are evaluated and the most reliable are adopted. The proposed model defines four key points—cracking, peak, stable post-peak, and ultimate—based on elastic analysis, P–M interaction, and modified deformation relationships. The results demonstrate conservative predictive performance. Nevertheless, further studies are required to extend the applicability of the model to higher axial load ratios, broader steel section ratios, and more reliable elastic modulus models for HyFC.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111274"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192525","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111256
Juliano Branjão Zonta , Felipe Piana Vendramell Ferreira , Alexandre Rossi , Konstantinos Daniel Tsavdaridis
This study assesses the structural behaviour of steel-concrete composite beams with elliptically-based web openings under hogging moments. A finite element model is developed and validated using ABAQUS software. A parametric study is conducted, considering variations in the opening key geometric parameters, hogging moment distribution, unrestrained length, and cross-section dimensions. The predictive accuracy of existing design standards, such as ABNT NBR 8800:2024 and prEN 1994–1–1:2024, for LDB is evaluated based on different approaches for calculating the elastic critical moment (Mcr). The results indicated that the hogging moment distribution significantly influenced the resistance, with uniform hogging moments representing the most critical scenario. I-section with more slender flanges and webs enhance LDB resistance but may lead to web-post yielding and buckling. Using Mcr obtained from linear buckling analysis improved ultimate moment predictions, when combined with the specific case reduction factor from EC3, generally outperformed other methods despite some non-conservative results. Between code-based procedures, the ABNT NBR 8800:2024 showed better agreement with numerical predictions than prEN 1994–1–1:2024 using the general case. Additionally, a numerical study comparing composite beams with elliptically-based and circular web openings was carried out, revealing that under gradient hogging moment, elliptically-based web openings exhibited on average 2.33 % higher load-bearing capacity and stiffness.
{"title":"Stability of steel-concrete composite beams with elliptically-based web openings under hogging moments","authors":"Juliano Branjão Zonta , Felipe Piana Vendramell Ferreira , Alexandre Rossi , Konstantinos Daniel Tsavdaridis","doi":"10.1016/j.istruc.2026.111256","DOIUrl":"10.1016/j.istruc.2026.111256","url":null,"abstract":"<div><div>This study assesses the structural behaviour of steel-concrete composite beams with elliptically-based web openings under hogging moments. A finite element model is developed and validated using ABAQUS software. A parametric study is conducted, considering variations in the opening key geometric parameters, hogging moment distribution, unrestrained length, and cross-section dimensions. The predictive accuracy of existing design standards, such as ABNT NBR 8800:2024 and prEN 1994–1–1:2024, for LDB is evaluated based on different approaches for calculating the elastic critical moment (<em>M</em><sub><em>cr</em></sub>). The results indicated that the hogging moment distribution significantly influenced the resistance, with uniform hogging moments representing the most critical scenario. I-section with more slender flanges and webs enhance LDB resistance but may lead to web-post yielding and buckling. Using <em>M</em><sub><em>cr</em></sub> obtained from linear buckling analysis improved ultimate moment predictions, when combined with the specific case reduction factor from EC3, generally outperformed other methods despite some non-conservative results. Between code-based procedures, the ABNT NBR 8800:2024 showed better agreement with numerical predictions than prEN 1994–1–1:2024 using the general case. Additionally, a numerical study comparing composite beams with elliptically-based and circular web openings was carried out, revealing that under gradient hogging moment, elliptically-based web openings exhibited on average 2.33 % higher load-bearing capacity and stiffness.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111256"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192608","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111257
Haoxuan Dong , Tianhong Yan , Weigang Wang , Xiushi Cui , Guoqiang Zhou
In engineering, structural model updating often faces challenges such as strong nonlinearity and high dimensionality of the updating parameters. Traditional optimization algorithms tend to get trapped in local optima and demonstrate low convergence efficiency when dealing with such problems. Although the Whale Optimization Algorithm (WOA) boasts stronger optimization capability than traditional algorithms, it struggles to balance exploration and exploitation. To address the above issues, this study proposes a model updating method based on the Response Surface Methodology (RSM) and the Improved Whale Optimization Algorithm (ImWOA). The ImWOA algorithm incorporates the improved Tent chaotic mapping to optimize the spatial distribution of the initial population, and adjusts the core parameter a for balancing the algorithm's exploration and exploitation capabilities via a nonlinear equation, thus achieving their collaborative optimization and further enhancing the global optimization performance and solution accuracy of the algorithm. To evaluate the performance of ImWOA, this study selected multiple benchmark test functions of varying dimensions and types, and compared it with the Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and the standard WOA. The results show that ImWOA outperforms other algorithms in both exploration capability and optimization accuracy. To verify the effectiveness and applicability of the proposed method, multi-scenario case studies were conducted: it was first applied to the model updating of a cantilever beam, where the maximum error of natural frequencies was reduced from 9.9 % (pre-updating) to 1.6 % (post-updating), and the mode shapes were more consistent with the measured results. Furthermore, the method was applied to the model updating of a more complex jacket benchmark experimental model to simulate complex structural scenarios in practical engineering. The study confirms that the proposed RSM-ImWOA method can effectively solve the problems in high-dimensional and strongly nonlinear structural model updating, and possesses good engineering practical value.
{"title":"Structural model updating based on response surface and improved whale optimization algorithm","authors":"Haoxuan Dong , Tianhong Yan , Weigang Wang , Xiushi Cui , Guoqiang Zhou","doi":"10.1016/j.istruc.2026.111257","DOIUrl":"10.1016/j.istruc.2026.111257","url":null,"abstract":"<div><div>In engineering, structural model updating often faces challenges such as strong nonlinearity and high dimensionality of the updating parameters. Traditional optimization algorithms tend to get trapped in local optima and demonstrate low convergence efficiency when dealing with such problems. Although the Whale Optimization Algorithm (WOA) boasts stronger optimization capability than traditional algorithms, it struggles to balance exploration and exploitation. To address the above issues, this study proposes a model updating method based on the Response Surface Methodology (RSM) and the Improved Whale Optimization Algorithm (ImWOA). The ImWOA algorithm incorporates the improved Tent chaotic mapping to optimize the spatial distribution of the initial population, and adjusts the core parameter a for balancing the algorithm's exploration and exploitation capabilities via a nonlinear equation, thus achieving their collaborative optimization and further enhancing the global optimization performance and solution accuracy of the algorithm. To evaluate the performance of ImWOA, this study selected multiple benchmark test functions of varying dimensions and types, and compared it with the Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and the standard WOA. The results show that ImWOA outperforms other algorithms in both exploration capability and optimization accuracy. To verify the effectiveness and applicability of the proposed method, multi-scenario case studies were conducted: it was first applied to the model updating of a cantilever beam, where the maximum error of natural frequencies was reduced from 9.9 % (pre-updating) to 1.6 % (post-updating), and the mode shapes were more consistent with the measured results. Furthermore, the method was applied to the model updating of a more complex jacket benchmark experimental model to simulate complex structural scenarios in practical engineering. The study confirms that the proposed RSM-ImWOA method can effectively solve the problems in high-dimensional and strongly nonlinear structural model updating, and possesses good engineering practical value.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111257"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192131","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 : 2026-02-05DOI: 10.1016/j.istruc.2026.111249
Shiwei Hou , Shengyin Wang , Wenhao Zhang , Xiuli Du
Seismic fragility analysis is a critical component in the performance-based seismic design of metro stations. However, the central columns of metro stations are seismically vulnerable components and prone to brittle failure during earthquakes. This study uses a two-story, three-span metro station in Jiangsu, China, as the case study. Focusing on the structural design of central columns, a three-dimensional nonlinear finite element model considering soil-structure interaction is established. The seismic responses of four types of central columns, namely Frame Column (FC), Split Column (SC), Centrally Reinforced Column (CRC), and Truncated Column (TC), are analyzed under various seismic waves and intensity levels. The deformation characteristics of different column types are evaluated and compared, including ductility and energy dissipation. Furthermore, the uncertainty of ground motions is considered, and incremental dynamic analysis (IDA) is conducted to assess the seismic fragility of metro stations with different central column types. Fragility curves under various conditions are developed, and structural vulnerability indexes are quantitatively computed. The results indicate that: The ductility advantage of functional columns is weakened under high axial compression ratios coupled with large horizontal deformations, leading to an increase in failure probability. In reducing the probability of structural failure, the centrally reinforced column performs best, followed by the truncated column, while the split column performs worst. Compared to the frame column, the split, truncated, and centrally reinforced columns exhibit higher failure probabilities when PGA exceeds 0.7 g, 0.9 g, and 0.98 g, respectively. The findings can provide a reference for the seismic mitigation design of metro station structures.
{"title":"Research on the seismic fragility of metro stations considering central column structure types","authors":"Shiwei Hou , Shengyin Wang , Wenhao Zhang , Xiuli Du","doi":"10.1016/j.istruc.2026.111249","DOIUrl":"10.1016/j.istruc.2026.111249","url":null,"abstract":"<div><div>Seismic fragility analysis is a critical component in the performance-based seismic design of metro stations. However, the central columns of metro stations are seismically vulnerable components and prone to brittle failure during earthquakes. This study uses a two-story, three-span metro station in Jiangsu, China, as the case study. Focusing on the structural design of central columns, a three-dimensional nonlinear finite element model considering soil-structure interaction is established. The seismic responses of four types of central columns, namely Frame Column (FC), Split Column (SC), Centrally Reinforced Column (CRC), and Truncated Column (TC), are analyzed under various seismic waves and intensity levels. The deformation characteristics of different column types are evaluated and compared, including ductility and energy dissipation. Furthermore, the uncertainty of ground motions is considered, and incremental dynamic analysis (IDA) is conducted to assess the seismic fragility of metro stations with different central column types. Fragility curves under various conditions are developed, and structural vulnerability indexes are quantitatively computed. The results indicate that: The ductility advantage of functional columns is weakened under high axial compression ratios coupled with large horizontal deformations, leading to an increase in failure probability. In reducing the probability of structural failure, the centrally reinforced column performs best, followed by the truncated column, while the split column performs worst. Compared to the frame column, the split, truncated, and centrally reinforced columns exhibit higher failure probabilities when <em>PGA</em> exceeds 0.7 g, 0.9 g, and 0.98 g, respectively. The findings can provide a reference for the seismic mitigation design of metro station structures.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111249"},"PeriodicalIF":4.3,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192135","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 : 2026-01-29DOI: 10.1016/j.istruc.2026.111203
Jixing Cao , Zhiqi Wang , Maolin Tian , Hongyu Jia , Chen Shi , Zhanzhong Yin
Cracks in bridge piers threaten infrastructure safety, but existing detection methods often fail to automatically capture fine geometric characteristics and provide multi-dimensional damage indicators. To overcome limitations like complex environment interference, poor point cloud reconstruction quality and incomplete damage analysis, this paper proposes an automated point cloud-based method for bridge pier crack detection and quantitative evaluation. The novelty of this method lies in a comprehensive multi-dimensional assessment framework. Beyond conventional geometric parameters including crack length, width and fractal dimension, the method innovatively integrates frequency-domain analysis via 2D power spectral density and energy distribution assessment via damage component amplitude, which enables thorough quantitative characterization of crack severity and propagation. The process involves acquiring multi-view pier images, identifying and labeling cracks via advanced edge detection and adaptive threshold segmentation, and then reconstructing a high-quality 3D point cloud model with accurate crack morphology through incremental reconstruction, stereo matching and depth fusion. Experimental validation on concrete piers confirms high effectiveness and precision: the relative errors of length measurement are below 5 % and the absolute errors of width detection are within 0.6 mm. This automated and high-precision technique enhances structural health monitoring, improves inspection accuracy, guides maintenance decisions and supports predictive maintenance in infrastructure management.
{"title":"Point cloud-based crack detection and quantitative assessment for bridge piers","authors":"Jixing Cao , Zhiqi Wang , Maolin Tian , Hongyu Jia , Chen Shi , Zhanzhong Yin","doi":"10.1016/j.istruc.2026.111203","DOIUrl":"10.1016/j.istruc.2026.111203","url":null,"abstract":"<div><div>Cracks in bridge piers threaten infrastructure safety, but existing detection methods often fail to automatically capture fine geometric characteristics and provide multi-dimensional damage indicators. To overcome limitations like complex environment interference, poor point cloud reconstruction quality and incomplete damage analysis, this paper proposes an automated point cloud-based method for bridge pier crack detection and quantitative evaluation. The novelty of this method lies in a comprehensive multi-dimensional assessment framework. Beyond conventional geometric parameters including crack length, width and fractal dimension, the method innovatively integrates frequency-domain analysis via 2D power spectral density and energy distribution assessment via damage component amplitude, which enables thorough quantitative characterization of crack severity and propagation. The process involves acquiring multi-view pier images, identifying and labeling cracks via advanced edge detection and adaptive threshold segmentation, and then reconstructing a high-quality 3D point cloud model with accurate crack morphology through incremental reconstruction, stereo matching and depth fusion. Experimental validation on concrete piers confirms high effectiveness and precision: the relative errors of length measurement are below 5 % and the absolute errors of width detection are within 0.6 mm. This automated and high-precision technique enhances structural health monitoring, improves inspection accuracy, guides maintenance decisions and supports predictive maintenance in infrastructure management.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111203"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079620","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 : 2026-01-29DOI: 10.1016/j.istruc.2026.111195
Kashan Khan , Kejia Yang , Lu Jiang , Zhong Tao , Hongzhi Su , Zhihua Chen , Jie Li , Junding Liu , Jia-Bao Yan
To enhance seismic resilience and accelerate construction in prefabricated steel–concrete composite buildings, this study experimentally and analytically investigates the seismic performance of concrete-filled steel tubular (CFST) column–partially encased composite (PEC) beam joints. Six full-scale joint specimens representing three connection concepts (steel H-beam, monolithic PEC, and cast-free thickened flange) were subjected to combined axial–lateral quasi-static cyclic loading to evaluate lateral strength, deformation capacity, energy dissipation, stiffness degradation, and failure mechanisms. The results show that the cast-free thickened flange joint exhibited a significantly more ductile and stable hysteretic response compared with conventional steel and monolithic PEC joints, with delayed local buckling and distributed damage. The optimized cast-free configuration achieved the highest average lateral strength (102.8 kN), ultimate drift ratio (1/22), and ductility coefficient (μ = 7.9), corresponding to increases of approximately 13 % in strength, 140 % in deformation capacity, and over 113 % in ductility relative to the steel H-beam reference joints, while maintaining comparable initial stiffness. Its cumulative energy dissipation reached approximately 335 kJ, accompanied by stable post-yield stiffness retention. Nonlinear finite element (FE) models accurately reproduced the experimental hysteresis behavior and damage evolution, with mean test-to-FE ratios of 1.00 for strength, 1.40 for initial stiffness, and 0.70 for displacement capacity. Design-code-based predictions were further evaluated using GB 50010–2010, T/CECS 512–2018, and T/CECS 719–2020. Flexural capacity predictions were conservative, with a mean ratio of , while shear capacity estimates showed good agreement, with a mean ratio of . The results confirm the effectiveness of the cast-free thickened flange joint in improving the seismic performance of CFST column–PEC beam frames, while the validated FE and analytical models provide a sound basis for design and optimization.
{"title":"Experimental and analytical study on seismic performance of concrete-filled steel tubular column–partially encased composite beam connections","authors":"Kashan Khan , Kejia Yang , Lu Jiang , Zhong Tao , Hongzhi Su , Zhihua Chen , Jie Li , Junding Liu , Jia-Bao Yan","doi":"10.1016/j.istruc.2026.111195","DOIUrl":"10.1016/j.istruc.2026.111195","url":null,"abstract":"<div><div>To enhance seismic resilience and accelerate construction in prefabricated steel–concrete composite buildings, this study experimentally and analytically investigates the seismic performance of concrete-filled steel tubular (CFST) column–partially encased composite (PEC) beam joints. Six full-scale joint specimens representing three connection concepts (steel H-beam, monolithic PEC, and cast-free thickened flange) were subjected to combined axial–lateral quasi-static cyclic loading to evaluate lateral strength, deformation capacity, energy dissipation, stiffness degradation, and failure mechanisms. The results show that the cast-free thickened flange joint exhibited a significantly more ductile and stable hysteretic response compared with conventional steel and monolithic PEC joints, with delayed local buckling and distributed damage. The optimized cast-free configuration achieved the highest average lateral strength (102.8 kN), ultimate drift ratio (1/22), and ductility coefficient (<em>μ</em> = 7.9), corresponding to increases of approximately 13 % in strength, 140 % in deformation capacity, and over 113 % in ductility relative to the steel H-beam reference joints, while maintaining comparable initial stiffness. Its cumulative energy dissipation reached approximately 335 kJ, accompanied by stable post-yield stiffness retention. Nonlinear finite element (FE) models accurately reproduced the experimental hysteresis behavior and damage evolution, with mean test-to-FE ratios of 1.00 for strength, 1.40 for initial stiffness, and 0.70 for displacement capacity. Design-code-based predictions were further evaluated using GB 50010–2010, T/CECS 512–2018, and T/CECS 719–2020. Flexural capacity predictions were conservative, with a mean ratio of <span><math><mrow><mfrac><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>u</mi><mo>,</mo><mi>test</mi></mrow></msub></mrow><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>u</mi><mo>,</mo><mi>GB</mi><mn>50010</mn></mrow></msub></mrow></mfrac><mo>=</mo><mspace></mspace><mn>1.70</mn></mrow></math></span>, while shear capacity estimates showed good agreement, with a mean ratio of <span><math><mrow><mfrac><mrow><msub><mrow><mi>V</mi></mrow><mrow><mi>u</mi><mo>,</mo><mi>test</mi></mrow></msub></mrow><mrow><msub><mrow><mi>V</mi></mrow><mrow><mi>u</mi><mo>,</mo><mi>T</mi><mo>/</mo><mi>CECS</mi><mn>512</mn></mrow></msub></mrow></mfrac><mo>=</mo><mspace></mspace><mn>0.93</mn></mrow></math></span>. The results confirm the effectiveness of the cast-free thickened flange joint in improving the seismic performance of CFST column–PEC beam frames, while the validated FE and analytical models provide a sound basis for design and optimization.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111195"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079621","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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