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}
Pub Date : 2026-01-29DOI: 10.1016/j.istruc.2026.111210
Yao Yao , Shuangjie Zheng , Chen Zhao
To enhance the steel section at notched holes designed for rebar installation, an innovative notched T-perfobond connector was developed by integrating flanges onto the perfobond rib. Comprehensive parametric analyses were conducted through the establishment of 51 finite element models simulating push-out test specimens. The shear capacity, shear stiffness, and load-slip response characteristics of the notched T-perfobond connectors were quantified and compared with existing connector types. Results indicate that increasing rib thickness and steel strength constitute the most effective enhancement strategies, whereas flange width exhibits an optimal value for maximizing connector performance. Through nonlinear regression analysis, an explicit shear capacity formula is derived, incorporating the previously neglected flange compression component, which on average accounts for 18 % of the shear capacity. A dimensionless analytical model is verified for predicting the load-slip relationships of notched T-perfobond connectors. These findings provide a theoretical basis for the optimization and practical implementation of this novel connector in composite structures.
{"title":"Analytical model for shear behavior of notched T-perfobond connectors","authors":"Yao Yao , Shuangjie Zheng , Chen Zhao","doi":"10.1016/j.istruc.2026.111210","DOIUrl":"10.1016/j.istruc.2026.111210","url":null,"abstract":"<div><div>To enhance the steel section at notched holes designed for rebar installation, an innovative notched T-perfobond connector was developed by integrating flanges onto the perfobond rib. Comprehensive parametric analyses were conducted through the establishment of 51 finite element models simulating push-out test specimens. The shear capacity, shear stiffness, and load-slip response characteristics of the notched T-perfobond connectors were quantified and compared with existing connector types. Results indicate that increasing rib thickness and steel strength constitute the most effective enhancement strategies, whereas flange width exhibits an optimal value for maximizing connector performance. Through nonlinear regression analysis, an explicit shear capacity formula is derived, incorporating the previously neglected flange compression component, which on average accounts for 18 % of the shear capacity. A dimensionless analytical model is verified for predicting the load-slip relationships of notched T-perfobond connectors. These findings provide a theoretical basis for the optimization and practical implementation of this novel connector in composite structures.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111210"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079713","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.2026.111176
Farhang Ebrahimi , Vahid Broujerdian , Esmaeil Mohammadi Dehcheshmeh , Mohammad Salehi
Hybrid Isolated-Rocking (HIR) columns comprising precast concrete segments, unbonded post-tensioning tendons, and lead rubber bearings offer promising seismic performance by enabling rocking motion, self-centering, and energy dissipation. This study presents a novel two-dimensional finite element framework for simulating the seismic behavior of HIR columns. A modified bearing element was developed in OpenSees to account for the coupled effects of axial load and bending moment on shear behavior. The proposed model was validated against detailed three-dimensional simulations conducted in ABAQUS. A comprehensive parametric study was carried out to evaluate the key design parameters, including the maximum achievable shear strain, number and location of bearings, and their characteristic strength. Furthermore, the effect of vertical earthquake excitation was assessed using time-history analyses under far-field ground motions. The results indicated that increasing the characteristic strength of the bearings () can enhance the column’s effective damping up to 20 %, thereby reducing its seismic demands. Additionally, the results indicated that positioning the bearings within the upper third of the column height enhances energy dissipation and reduces lateral displacements. Notably, the vertical component of far-field earthquake excitation has a negligible influence on the seismic response of HIR columns, due to the dominant role of axial loads from gravity and post-tensioning.
{"title":"Development of a two-dimensional finite element framework for hybrid isolated-rocking columns: Assessing seismic performance and key design parameters","authors":"Farhang Ebrahimi , Vahid Broujerdian , Esmaeil Mohammadi Dehcheshmeh , Mohammad Salehi","doi":"10.1016/j.istruc.2026.111176","DOIUrl":"10.1016/j.istruc.2026.111176","url":null,"abstract":"<div><div>Hybrid Isolated-Rocking (HIR) columns comprising precast concrete segments, unbonded post-tensioning tendons, and lead rubber bearings offer promising seismic performance by enabling rocking motion, self-centering, and energy dissipation. This study presents a novel two-dimensional finite element framework for simulating the seismic behavior of HIR columns. A modified bearing element was developed in OpenSees to account for the coupled effects of axial load and bending moment on shear behavior. The proposed model was validated against detailed three-dimensional simulations conducted in ABAQUS. A comprehensive parametric study was carried out to evaluate the key design parameters, including the maximum achievable shear strain, number and location of bearings, and their characteristic strength. Furthermore, the effect of vertical earthquake excitation was assessed using time-history analyses under far-field ground motions. The results indicated that increasing the characteristic strength of the bearings (<span><math><msub><mrow><mi>Q</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span>) can enhance the column’s effective damping up to 20 %, thereby reducing its seismic demands. Additionally, the results indicated that positioning the bearings within the upper third of the column height enhances energy dissipation and reduces lateral displacements. Notably, the vertical component of far-field earthquake excitation has a negligible influence on the seismic response of HIR columns, due to the dominant role of axial loads from gravity and post-tensioning.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111176"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079619","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.2026.111236
Zhen Li , Yunfeng Zou , Yunkui Kong , Xuhui He , Rui Gui , Zhaoguang Liu
The rail-cum-road bridge with twin separated parallel decks is recognized for its outstanding traffic-carrying capacity. However, the complex aerodynamic interactions between girders result in significant aerodynamic interference effects. Understanding how such interference influences the vortex-induced vibration (VIV) behaviour of separated rail-cum-road bridges remains a major challenge. In this study, full-bridge aeroelastic wind tunnel tests were conducted to investigate factors such as the wind yaw angle, separation spacing and aerodynamic damping measures that affect aerodynamic interference. The results indicated that significant VIV responses occurred only when the railway deck was on the windward side. The maximum dimensionless responses of the railway girder and the highway girder reached 0.0154 and 0.0054, respectively. As the wind yaw angle increased from 0° to 45°, the VIV amplitude first increased and then decreased, indicating that 0° was not the most critical wind angle for the occurrence of VIV. The deformation of the full-bridge aeroelastic model may differ from the actual modal deformation of the prototype bridge, primarily due to the non-uniform stiffness in the model. The effect of girder spacing on the VIV amplitude was most pronounced at small spacing values. When the spacing exceeded three times the original distance, the VIVs disappeared. Installing wind barriers on the railway girder effectively suppressed the VIV and influenced the vibration characteristics of the adjacent highway girder.
{"title":"Experimental investigation of aerodynamic interference effects on vortex-induced vibrations in separated rail-cum-road bridges","authors":"Zhen Li , Yunfeng Zou , Yunkui Kong , Xuhui He , Rui Gui , Zhaoguang Liu","doi":"10.1016/j.istruc.2026.111236","DOIUrl":"10.1016/j.istruc.2026.111236","url":null,"abstract":"<div><div>The rail-cum-road bridge with twin separated parallel decks is recognized for its outstanding traffic-carrying capacity. However, the complex aerodynamic interactions between girders result in significant aerodynamic interference effects. Understanding how such interference influences the vortex-induced vibration (VIV) behaviour of separated rail-cum-road bridges remains a major challenge. In this study, full-bridge aeroelastic wind tunnel tests were conducted to investigate factors such as the wind yaw angle, separation spacing and aerodynamic damping measures that affect aerodynamic interference. The results indicated that significant VIV responses occurred only when the railway deck was on the windward side. The maximum dimensionless responses of the railway girder and the highway girder reached 0.0154 and 0.0054, respectively. As the wind yaw angle increased from 0° to 45°, the VIV amplitude first increased and then decreased, indicating that 0° was not the most critical wind angle for the occurrence of VIV. The deformation of the full-bridge aeroelastic model may differ from the actual modal deformation of the prototype bridge, primarily due to the non-uniform stiffness in the model. The effect of girder spacing on the VIV amplitude was most pronounced at small spacing values. When the spacing exceeded three times the original distance, the VIVs disappeared. Installing wind barriers on the railway girder effectively suppressed the VIV and influenced the vibration characteristics of the adjacent highway girder.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111236"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079622","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.2026.111200
Hongchun Li , Zeyang Sun , Yi Zheng , Liuzhen Yao , Xiaoning Cai
Steel bar corrosion significantly compromises the durability of concrete structures, and utilizing corrosion-resistant reinforcements such as stainless steel (SS) and basalt fiber-reinforced polymer (BFRP) bars offers a direct and effective strategy for enhancing the service life and safety performance of structures. Previous studies have indicated that the mechanical behavior of concrete columns reinforced with SS bars remains insufficiently investigated, with corresponding computational methods still limited. This study investigates the axial compression performance of concrete columns reinforced with SS and BFRP bars. Finite element models (FEMs) were developed and validated against experimental results. Subsequently, an extensive parametric study involving 232 FEMs was conducted to evaluate the influence of reinforcement ratio, longitudinal bar type, stirrup spacing, and concrete strength. The finite element (FE) analysis results revealed that the stirrups effectively enhanced the core concrete strength, with a maximum increase of 28.6 % under a confining stress of 3.17 MPa. Meanwhile, the load contribution of SS longitudinal bars exceeded that of BFRP bars, reaching a maximum of 19.6 % at a reinforcement ratio of 3.41 %, compared to 9.9 % for BFRP bars under the same ratio. Notably, at the peak load, neither the SS longitudinal bars nor the stirrups had reached their proof strength (f0.2), indicating underutilization of the material. Based on the actual stress state of both longitudinal bars and stirrups at peak load, a new calculation method for the compressive bearing capacity was proposed. Specifically, the contribution of longitudinal bars in compression was quantified by introducing a strength correction coefficient. Furthermore, a model for predicting the peak strength of SS stirrup-confined concrete columns was established based on the William-Warnke failure criterion. Validation against experimental data confirms that the proposed method accurately predicts the axial compressive bearing capacity of concrete columns reinforced with corrosion-resistant reinforcements.
{"title":"Axial compression behavior of concrete columns reinforced with stainless steel and BFRP bars: Numerical simulation and predictive models","authors":"Hongchun Li , Zeyang Sun , Yi Zheng , Liuzhen Yao , Xiaoning Cai","doi":"10.1016/j.istruc.2026.111200","DOIUrl":"10.1016/j.istruc.2026.111200","url":null,"abstract":"<div><div>Steel bar corrosion significantly compromises the durability of concrete structures, and utilizing corrosion-resistant reinforcements such as stainless steel (SS) and basalt fiber-reinforced polymer (BFRP) bars offers a direct and effective strategy for enhancing the service life and safety performance of structures. Previous studies have indicated that the mechanical behavior of concrete columns reinforced with SS bars remains insufficiently investigated, with corresponding computational methods still limited. This study investigates the axial compression performance of concrete columns reinforced with SS and BFRP bars. Finite element models (FEMs) were developed and validated against experimental results. Subsequently, an extensive parametric study involving 232 FEMs was conducted to evaluate the influence of reinforcement ratio, longitudinal bar type, stirrup spacing, and concrete strength. The finite element (FE) analysis results revealed that the stirrups effectively enhanced the core concrete strength, with a maximum increase of 28.6 % under a confining stress of 3.17 MPa. Meanwhile, the load contribution of SS longitudinal bars exceeded that of BFRP bars, reaching a maximum of 19.6 % at a reinforcement ratio of 3.41 %, compared to 9.9 % for BFRP bars under the same ratio. Notably, at the peak load, neither the SS longitudinal bars nor the stirrups had reached their proof strength (<em>f</em><sub>0.2</sub>), indicating underutilization of the material. Based on the actual stress state of both longitudinal bars and stirrups at peak load, a new calculation method for the compressive bearing capacity was proposed. Specifically, the contribution of longitudinal bars in compression was quantified by introducing a strength correction coefficient. Furthermore, a model for predicting the peak strength of SS stirrup-confined concrete columns was established based on the William-Warnke failure criterion. Validation against experimental data confirms that the proposed method accurately predicts the axial compressive bearing capacity of concrete columns reinforced with corrosion-resistant reinforcements.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111200"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079712","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.2026.111117
Elham Rajabi , Ali Asghar Rad
During earthquakes, considerable amount of energy referred to as input energy is transferred into the structure. This energy is partially dissipated through damping and inelastic yielding/deformations of structural and non-structural components. Since the absorbed seismic energy plays a crucial role in seismic performance, evaluating of this energy is particular importance. It becomes even more critical when considering the combined effects of successive earthquakes and structural irregularities. The consequences of the lack of structural regularity, such as torsion, can lead to unpredictable structural behavior, especially in buildings already damaged by the previous earthquake. Unfortunately, the occurrence of successive earthquakes has not yet been adequately considered in the seismic codes. Thus, implementing an energy-based method in earthquake engineering seems essential considering the above conditions. In this study, dual Linked-Column-Frame (LCF) as a modern lateral force resisting system with shear and flexural linked beams were employed in twelve regular/irregular steel structures. The distributions of the seismic input energy caused by single/consecutive shocks, as well as energy-related demands were evaluated. To identify the optimal criterion for demands related to energy, indices such as efficiency, proficiency, practicality, and relative sufficiency were evaluated, and potentially optimal candidates were identified. The results revealed a significant correlation between energy-based demands and conventional displacement-based demands. Finally, it was demonstrated that the velocity spectrum intensity of the second shock (VSIa) is the optimal intensity measure for the selected demands, namely hysteretic energy of link beams (Eh-Linked Beams), maximum kinetic energy (Max Ek), and summation of hysteretic energies (∑Eh).
{"title":"Investigation of the seismic energy demands and optimal intensity measures for irregular steel frames with dual LCF system under sequence of critical shocks","authors":"Elham Rajabi , Ali Asghar Rad","doi":"10.1016/j.istruc.2026.111117","DOIUrl":"10.1016/j.istruc.2026.111117","url":null,"abstract":"<div><div>During earthquakes, considerable amount of energy referred to as <em>input energy</em> is transferred into the structure. This energy is partially dissipated through damping and inelastic yielding/deformations of structural and non-structural components. Since the absorbed seismic energy plays a crucial role in seismic performance, evaluating of this energy is particular importance. It becomes even more critical when considering the combined effects of successive earthquakes and structural irregularities. The consequences of the lack of structural regularity, such as torsion, can lead to unpredictable structural behavior, especially in buildings already damaged by the previous earthquake. Unfortunately, the occurrence of successive earthquakes has not yet been adequately considered in the seismic codes. Thus, implementing an energy-based method in earthquake engineering seems essential considering the above conditions. In this study, dual Linked-Column-Frame (LCF) as a modern lateral force resisting system with shear and flexural linked beams were employed in twelve regular/irregular steel structures. The distributions of the seismic input energy caused by single/consecutive shocks, as well as energy-related demands were evaluated. To identify the optimal criterion for demands related to energy, indices such as efficiency, proficiency, practicality, and relative sufficiency were evaluated, and potentially optimal candidates were identified. The results revealed a significant correlation between energy-based demands and conventional displacement-based demands. Finally, it was demonstrated that the velocity spectrum intensity of the second shock (VSI<sub>a</sub>) is the optimal intensity measure for the selected demands, namely hysteretic energy of link beams (E<sub>h-Linked Beams</sub>), maximum kinetic energy (Max E<sub>k</sub>), and summation of hysteretic energies (∑E<sub>h</sub>).</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111117"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079716","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.2026.111165
Yun Chen , Yingxiong Wu , Feifei Sun , Mianyue Yang , Yunchao Zheng
The hourglass added damping and stiffness (HADAS) damper exhibits a continuous increase in load-carrying capacity after yielding due to strain hardening, which adversely transfers greater forces to the connected frame members and may cause increased damage. To mitigate this drawback, a novel metal damper (i.e., Graded Failure Damper (GFD)) was proposed. GFD consists of a weakly rhombic hole steel plate with varying heights or neck widths and multiple constant-section rhombic hole steel plates connected in parallel. Its staged failure is achieved by regulating the geometric parameters of the weakly rhombic hole steel plate and effectively controlling the trend of the horizontal force after yielding. Subsequently, the low-cycle reciprocating load tests of GFDs and HADAS demonstrated satisfactory performance in avoiding continuous load increase. Compared to HADAS, the GFD showed reductions in maximum load-bearing capacity, strengthening coefficient, and loop energy dissipation by 25.4 %, 25.8 %, and 20 %, respectively, while its maximum equivalent damping coefficient increased by 10 %. In addition, given that the ultimate bearing capacity of the weakly rhombic hole steel plate is a crucial design characteristic, a calculation formula for the ultimate load was proposed based on theoretical and finite-element parameter analysis. To avoid errors that affect calculation results, the calculation formula applies to the neck width of weakly rhombic hole steel plates with a thickness greater than 4 mm.
{"title":"Hysteretic behavior and ultimate load prediction of the graded failure damper","authors":"Yun Chen , Yingxiong Wu , Feifei Sun , Mianyue Yang , Yunchao Zheng","doi":"10.1016/j.istruc.2026.111165","DOIUrl":"10.1016/j.istruc.2026.111165","url":null,"abstract":"<div><div>The hourglass added damping and stiffness (HADAS) damper exhibits a continuous increase in load-carrying capacity after yielding due to strain hardening, which adversely transfers greater forces to the connected frame members and may cause increased damage. To mitigate this drawback, a novel metal damper (i.e., Graded Failure Damper (GFD)) was proposed. GFD consists of a weakly rhombic hole steel plate with varying heights or neck widths and multiple constant-section rhombic hole steel plates connected in parallel. Its staged failure is achieved by regulating the geometric parameters of the weakly rhombic hole steel plate and effectively controlling the trend of the horizontal force after yielding. Subsequently, the low-cycle reciprocating load tests of GFDs and HADAS demonstrated satisfactory performance in avoiding continuous load increase. Compared to HADAS, the GFD showed reductions in maximum load-bearing capacity, strengthening coefficient, and loop energy dissipation by 25.4 %, 25.8 %, and 20 %, respectively, while its maximum equivalent damping coefficient increased by 10 %. In addition, given that the ultimate bearing capacity of the weakly rhombic hole steel plate is a crucial design characteristic, a calculation formula for the ultimate load was proposed based on theoretical and finite-element parameter analysis. To avoid errors that affect calculation results, the calculation formula applies to the neck width of weakly rhombic hole steel plates with a thickness greater than 4 mm.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111165"},"PeriodicalIF":4.3,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079734","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 : 2026-01-28DOI: 10.1016/j.istruc.2026.111204
Tiansong Ye , Bo Yuan , Shiyu Zheng , Yanhui Wei , Zhengrong Zhou
Phosphogypsum (PG) is a by-product of the phosphate industry that poses significant environmental risks due to its acidity, heavy metals, and radioactive elements. To promote its resource utilization, this study proposes a novel composite member: the PG-filled square stainless steel tube (PGFSST) column. Axial compression tests were conducted on 15 specimens to investigate the effects of tube wall thickness and PG strength. The results show that the stainless steel tube effectively delays cracking and mitigates the brittleness of PG, with failure modes including end bulging and mid-height shear failure. The strength enhancement index ranged from 1.29 to 1.47, indicating strong composite action. Finite element models developed in ABAQUS were validated against experimental data. Parametric studies revealed that peak axial stress is insensitive to section size, while peak strain and composite elastic modulus are size-dependent. Based on these findings, a modified ultimate capacity formula for PGFSST columns was proposed, improving the prediction accuracy of GB 50936–2014 from 0.79 to 1.00 and EN 1994–1–1 from 0.74 to 0.99.
{"title":"Experimental study on the axial behavior of phosphogypsum-based composite filled square stainless steel tubular columns","authors":"Tiansong Ye , Bo Yuan , Shiyu Zheng , Yanhui Wei , Zhengrong Zhou","doi":"10.1016/j.istruc.2026.111204","DOIUrl":"10.1016/j.istruc.2026.111204","url":null,"abstract":"<div><div>Phosphogypsum (PG) is a by-product of the phosphate industry that poses significant environmental risks due to its acidity, heavy metals, and radioactive elements. To promote its resource utilization, this study proposes a novel composite member: the PG-filled square stainless steel tube (PGFSST) column. Axial compression tests were conducted on 15 specimens to investigate the effects of tube wall thickness and PG strength. The results show that the stainless steel tube effectively delays cracking and mitigates the brittleness of PG, with failure modes including end bulging and mid-height shear failure. The strength enhancement index ranged from 1.29 to 1.47, indicating strong composite action. Finite element models developed in ABAQUS were validated against experimental data. Parametric studies revealed that peak axial stress is insensitive to section size, while peak strain and composite elastic modulus are size-dependent. Based on these findings, a modified ultimate capacity formula for PGFSST columns was proposed, improving the prediction accuracy of GB 50936–2014 from 0.79 to 1.00 and EN 1994–1–1 from 0.74 to 0.99.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111204"},"PeriodicalIF":4.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079727","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 : 2026-01-28DOI: 10.1016/j.istruc.2026.111202
Fangyi Li , Weian Huang , Qiang Zhang , Zijie Wang
As a classical auxetic metamaterial, the internal concave structure has become a hot spot in metamaterials research. However, most of the improved reinforced ribbed inner concave structures, although improving the problem of weakened stiffness existing in the traditional inner concave structures to a certain extent, also reduce the negative Poisson's ratio effect of the structure as a result, which has an impact on the comparison of energy absorption. To address this limitation, this paper proposes a novel composite honeycomb structure combining concave and rhombic configurations. This design enhances both compressive stability and energy absorption capacity per unit volume. For comparison, a hexagonal structure connected to straight rods is introduced. The energy absorption capabilities of these three configurations are investigated through quasi-static compression tests and finite element analysis. Results indicate that the novel composite honeycomb structure, composed of rhombic and concave cells, significantly enhances energy absorption. Its specific energy absorption efficiency surpasses the other two structures by 10 % and 65 %, respectively. It exhibits the lowest Poisson's ratio (-1) and a more stable compression deformation pattern than other configurations, with minimal stress fluctuations during the plateau phase and a standard deviation of 6.754 for the average plateau stress. Furthermore, multi-objective optimization of the novel composite honeycomb structure yielded parameters with low initial peak force and high specific energy absorption capacity. These findings offer new insights for metamaterial design by integrating composite honeycomb structures with reinforced ribs and internal concave surfaces to achieve optimization.
{"title":"Concave–rhombic hybrid honeycomb structures: Energy absorption mechanism and multi-objective optimization","authors":"Fangyi Li , Weian Huang , Qiang Zhang , Zijie Wang","doi":"10.1016/j.istruc.2026.111202","DOIUrl":"10.1016/j.istruc.2026.111202","url":null,"abstract":"<div><div>As a classical auxetic metamaterial, the internal concave structure has become a hot spot in metamaterials research. However, most of the improved reinforced ribbed inner concave structures, although improving the problem of weakened stiffness existing in the traditional inner concave structures to a certain extent, also reduce the negative Poisson's ratio effect of the structure as a result, which has an impact on the comparison of energy absorption. To address this limitation, this paper proposes a novel composite honeycomb structure combining concave and rhombic configurations. This design enhances both compressive stability and energy absorption capacity per unit volume. For comparison, a hexagonal structure connected to straight rods is introduced. The energy absorption capabilities of these three configurations are investigated through quasi-static compression tests and finite element analysis. Results indicate that the novel composite honeycomb structure, composed of rhombic and concave cells, significantly enhances energy absorption. Its specific energy absorption efficiency surpasses the other two structures by 10 % and 65 %, respectively. It exhibits the lowest Poisson's ratio (-1) and a more stable compression deformation pattern than other configurations, with minimal stress fluctuations during the plateau phase and a standard deviation of 6.754 for the average plateau stress. Furthermore, multi-objective optimization of the novel composite honeycomb structure yielded parameters with low initial peak force and high specific energy absorption capacity. These findings offer new insights for metamaterial design by integrating composite honeycomb structures with reinforced ribs and internal concave surfaces to achieve optimization.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"85 ","pages":"Article 111202"},"PeriodicalIF":4.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079708","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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