Pub Date : 2026-04-15Epub Date: 2026-02-10DOI: 10.1016/j.engstruct.2026.122328
Nahid Khodabakhshi , Theodora Mouka , Elias G. Dimitrakopoulos , David Trujillo , Alireza Khaloo
Full-culm bamboo is an eco-friendly construction material with remarkable mechanical properties. Due to the complex material properties and the tubular geometry, bamboo culms can fail under bending in a variety of mechanisms/modes. This study focuses on the effect of circumferential tension-shear interaction and the bimodulus elastic model (different compressive and tensile elastic moduli) on the failure of bamboo culms under flexure. Specifically, it compares the failure moment of these modes with the corresponding failure moment for longitudinal compression failure (disregarding the bimodulus behavior), splitting due to circumferential tension, shear parallel to the fibers, and Brazier instability. Findings indicate that bamboo culms under flexure are more likely either to fail under longitudinal compression (thick-walled culms) or to split at the side due to the interaction of shear and circumferential tension (thin-walled culms). Moreover, considering the bimodulus behavior results in a more precise longitudinal compression failure prediction compared to the standard bending theory. This study also validates the analytical approaches via conducting four-point flexural tests. It highlights the importance of mixed-mode failure and of the bimodulus elastic approach, contrary to the usual practice of disregarding these features in determining the failure moment of bamboo culms under flexure. Furthermore, the occurring strength values constitute a close approximation to the bending strength obtained according to ISO 22157:2019, effectively minimizing the need for bending tests and enabling accurate predictions based solely on culm geometric parameters and generic material properties.
{"title":"Analytical and experimental investigations on failure of bamboo culms in bending: Effects of shear-tension interaction and bimodulus material behavior","authors":"Nahid Khodabakhshi , Theodora Mouka , Elias G. Dimitrakopoulos , David Trujillo , Alireza Khaloo","doi":"10.1016/j.engstruct.2026.122328","DOIUrl":"10.1016/j.engstruct.2026.122328","url":null,"abstract":"<div><div>Full-culm bamboo is an eco-friendly construction material with remarkable mechanical properties. Due to the complex material properties and the tubular geometry, bamboo culms can fail under bending in a variety of mechanisms/modes. This study focuses on the effect of circumferential tension-shear interaction and the bimodulus elastic model (different compressive and tensile elastic moduli) on the failure of bamboo culms under flexure. Specifically, it compares the failure moment of these modes with the corresponding failure moment for longitudinal compression failure (disregarding the bimodulus behavior), splitting due to circumferential tension, shear parallel to the fibers, and Brazier instability. Findings indicate that bamboo culms under flexure are more likely either to fail under longitudinal compression (thick-walled culms) or to split at the side due to the interaction of shear and circumferential tension (thin-walled culms). Moreover, considering the bimodulus behavior results in a more precise longitudinal compression failure prediction compared to the standard bending theory. This study also validates the analytical approaches via conducting four-point flexural tests. It highlights the importance of mixed-mode failure and of the bimodulus elastic approach, contrary to the usual practice of disregarding these features in determining the failure moment of bamboo culms under flexure. Furthermore, the occurring strength values constitute a close approximation to the bending strength obtained according to ISO 22157:2019, effectively minimizing the need for bending tests and enabling accurate predictions based solely on culm geometric parameters and generic material properties.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122328"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185615","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 : 2026-04-15Epub Date: 2026-01-22DOI: 10.1016/j.engstruct.2026.122185
Faisal Nissar Malik , Haitham A. Ibrahim , Liang Cao , James Ricles , Amal Elawady , Arindam Gan Chowdhury
Real-time hybrid simulation (RTHS) is an advanced testing technique in which a structural system is divided into analytical and experimental substructures that are coupled in real time to capture the dynamic response of the complete system. While RTHS has been applied to wind-induced loading; conventional implementations typically rely on pre-recorded aerodynamic data from rigid wind tunnel models, thereby neglecting wind–structure interaction effects. This simplification limits the accuracy of response prediction because the interaction between structural motion and the surrounding airflow can have a significant influence on the wind-induced forces. To overcome this limitation, this study introduces a novel Multi-directional Real-time Aeroelastic Hybrid Simulation (RTAHS) framework that explicitly incorporates multi-directional aeroelastic effects into the evaluation of tall building response under wind loading. In the proposed approach, the structural system is modeled numerically as the analytical substructure, while the building facade is physically represented in a wind tunnel as the aero substructure, and any supplemental damping devices in the structure are modeled physically as the experimental substructure. At each time step, the equations of motion are solved to compute the displacements of the aero substructure, which are then imposed on the physical model in the wind tunnel through actuators. The real-time wind pressures are subsequently measured in this deformed configuration and integrated to determine the corresponding aeroelastic forces. A 40-story building equipped with nonlinear fluid viscous dampers in the outrigger system and a tuned mass damper at the roof is employed as a case study. Simulations are conducted with and without structural material nonlinearities, and the accuracy and robustness of the proposed framework is assessed. The RTAHS approach can be utilized to substantially enhance the realism and fidelity of wind-induced response predictions, offering a powerful tool for the design and performance assessment of tall buildings.
{"title":"Real-time multi-directional aeroelastic hybrid simulation for tall building response under wind loading","authors":"Faisal Nissar Malik , Haitham A. Ibrahim , Liang Cao , James Ricles , Amal Elawady , Arindam Gan Chowdhury","doi":"10.1016/j.engstruct.2026.122185","DOIUrl":"10.1016/j.engstruct.2026.122185","url":null,"abstract":"<div><div>Real-time hybrid simulation (RTHS) is an advanced testing technique in which a structural system is divided into analytical and experimental substructures that are coupled in real time to capture the dynamic response of the complete system. While RTHS has been applied to wind-induced loading; conventional implementations typically rely on pre-recorded aerodynamic data from rigid wind tunnel models, thereby neglecting wind–structure interaction effects. This simplification limits the accuracy of response prediction because the interaction between structural motion and the surrounding airflow can have a significant influence on the wind-induced forces. To overcome this limitation, this study introduces a novel Multi-directional Real-time Aeroelastic Hybrid Simulation (RTAHS) framework that explicitly incorporates multi-directional aeroelastic effects into the evaluation of tall building response under wind loading. In the proposed approach, the structural system is modeled numerically as the analytical substructure, while the building facade is physically represented in a wind tunnel as the aero substructure, and any supplemental damping devices in the structure are modeled physically as the experimental substructure. At each time step, the equations of motion are solved to compute the displacements of the aero substructure, which are then imposed on the physical model in the wind tunnel through actuators. The real-time wind pressures are subsequently measured in this deformed configuration and integrated to determine the corresponding aeroelastic forces. A 40-story building equipped with nonlinear fluid viscous dampers in the outrigger system and a tuned mass damper at the roof is employed as a case study. Simulations are conducted with and without structural material nonlinearities, and the accuracy and robustness of the proposed framework is assessed. The RTAHS approach can be utilized to substantially enhance the realism and fidelity of wind-induced response predictions, offering a powerful tool for the design and performance assessment of tall buildings.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122185"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036859","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 : 2026-04-15Epub Date: 2026-01-24DOI: 10.1016/j.engstruct.2026.122227
Xiaochen Wang , Zhejian Li , Hong Hao , Wensu Chen
Crash cushions are indispensable safety structures commonly installed on highways to mitigate damage caused by vehicle collisions. As the most critical component for energy absorption in crash cushions, innovating the structural design of energy-absorbing modules to enhance their energy absorption efficiency has become an urgent requirement for improving road safety. The paper presents a comprehensive study of the feasibility of using a full-scale kirigami-modified corrugated honeycomb (KC) structure as energy-absorbing module. This study conducted horizontal impact tests using a rigid car on full-scale KC modules adapted for crash cushion energy-absorbing modules, applying impact energy at the same order of magnitude as that in actual collisions, to investigate the dynamic response characteristics of the full-scale KC modules under different impact conditions. The influences of key variables, including collision velocity, impactor mass, impact energy, the number of folds, and the quantity of interlayers, on the deformation behavior and energy absorption performance of the specimens are investigated. The KC structure significantly outperforms the reinforced honeycomb (RHC) structure with a 51.4 % increase in energy absorption per unit length. The enhanced performance of the KC structure is attributed to its unique deformation mode, which facilitates more efficient energy dissipation. The results illustrate the potential of adopting KC structures as energy-absorbing modules for crash cushions, which can be easily tuned to accommodate different requirements for various energy-absorbing applications to resist vehicle collisions.
{"title":"Experimental study on energy absorption performance of kirigami-modified honeycomb module for crash cushion","authors":"Xiaochen Wang , Zhejian Li , Hong Hao , Wensu Chen","doi":"10.1016/j.engstruct.2026.122227","DOIUrl":"10.1016/j.engstruct.2026.122227","url":null,"abstract":"<div><div>Crash cushions are indispensable safety structures commonly installed on highways to mitigate damage caused by vehicle collisions. As the most critical component for energy absorption in crash cushions, innovating the structural design of energy-absorbing modules to enhance their energy absorption efficiency has become an urgent requirement for improving road safety. The paper presents a comprehensive study of the feasibility of using a full-scale kirigami-modified corrugated honeycomb (KC) structure as energy-absorbing module. This study conducted horizontal impact tests using a rigid car on full-scale KC modules adapted for crash cushion energy-absorbing modules, applying impact energy at the same order of magnitude as that in actual collisions, to investigate the dynamic response characteristics of the full-scale KC modules under different impact conditions. The influences of key variables, including collision velocity, impactor mass, impact energy, the number of folds, and the quantity of interlayers, on the deformation behavior and energy absorption performance of the specimens are investigated. The KC structure significantly outperforms the reinforced honeycomb (RHC) structure with a 51.4 % increase in energy absorption per unit length. The enhanced performance of the KC structure is attributed to its unique deformation mode, which facilitates more efficient energy dissipation. The results illustrate the potential of adopting KC structures as energy-absorbing modules for crash cushions, which can be easily tuned to accommodate different requirements for various energy-absorbing applications to resist vehicle collisions.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122227"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036932","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 : 2026-04-15Epub Date: 2026-01-24DOI: 10.1016/j.engstruct.2026.122246
Lei Tu , Weikun He , Hua Zhao , Chengjun Tan , Jiahe An , Junde Hu , Lizhi Lu
In composite structures composed of precast ultra-high performance concrete (UHPC) and cast-in-place normal-strength concrete (NC), the interface is often subjected to high shear demands, making its performance critical to the structural integrity. Previous studies have shown that interface geometry significantly influences interfacial shear strength, with grooved and sawtooth interfaces showing much higher capacity than flat interfaces. However, the underlying load transfer mechanisms remain unclear, and no unified predictive framework exists for UHPC–NC interfaces with different geometries. This study investigates interfacial shear behavior through both experimental and analytical approaches. Z-shaped direct shear tests were performed with nine parameter combinations, varying steel fiber volume fractions (1 %–4 %), interface geometries (flat, grooved, sawtooth), and shear reinforcement ratios (0.80 %–2.46 %). Crack propagation and failure modes were characterized using digital image correlation and post-test interface sectioning, while load–slip responses were also analyzed. Results indicate that interface geometry governs failure patterns: flat interfaces exhibited failure localized at the interface, while grooved and sawtooth interfaces formed irregular failure surfaces penetrating into the NC segment. This extension of the failure path activates the aggregate interlock effect within the NC, substantially enhancing shear resistance. Furthermore, a predictive model was developed by integrating the effects of cohesion, frictional resistance, and dowel action. Notably, aggregate interlock and steel fiber bridging—the primary contributors to cohesion—were quantitatively incorporated into the model. The model was validated against 30 datasets, showing strong agreement with experimental results (average: 1.00; standard deviation: 0.15). These findings provide theoretical support and practical guidance for the design and optimization of UHPC–NC composite interfaces.
{"title":"Influence of interface geometry on interfacial shear between precast UHPC and cast-in-place normal-strength concrete: Experimental and analytical investigation","authors":"Lei Tu , Weikun He , Hua Zhao , Chengjun Tan , Jiahe An , Junde Hu , Lizhi Lu","doi":"10.1016/j.engstruct.2026.122246","DOIUrl":"10.1016/j.engstruct.2026.122246","url":null,"abstract":"<div><div>In composite structures composed of precast ultra-high performance concrete (UHPC) and cast-in-place normal-strength concrete (NC), the interface is often subjected to high shear demands, making its performance critical to the structural integrity. Previous studies have shown that interface geometry significantly influences interfacial shear strength, with grooved and sawtooth interfaces showing much higher capacity than flat interfaces. However, the underlying load transfer mechanisms remain unclear, and no unified predictive framework exists for UHPC–NC interfaces with different geometries. This study investigates interfacial shear behavior through both experimental and analytical approaches. Z-shaped direct shear tests were performed with nine parameter combinations, varying steel fiber volume fractions (1 %–4 %), interface geometries (flat, grooved, sawtooth), and shear reinforcement ratios (0.80 %–2.46 %). Crack propagation and failure modes were characterized using digital image correlation and post-test interface sectioning, while load–slip responses were also analyzed. Results indicate that interface geometry governs failure patterns: flat interfaces exhibited failure localized at the interface, while grooved and sawtooth interfaces formed irregular failure surfaces penetrating into the NC segment. This extension of the failure path activates the aggregate interlock effect within the NC, substantially enhancing shear resistance. Furthermore, a predictive model was developed by integrating the effects of cohesion, frictional resistance, and dowel action. Notably, aggregate interlock and steel fiber bridging—the primary contributors to cohesion—were quantitatively incorporated into the model. The model was validated against 30 datasets, showing strong agreement with experimental results (average: 1.00; standard deviation: 0.15). These findings provide theoretical support and practical guidance for the design and optimization of UHPC–NC composite interfaces.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122246"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036934","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 : 2026-04-15Epub Date: 2026-01-23DOI: 10.1016/j.engstruct.2026.122221
Zhichao Lai, Shiji Zhang, Deren Lu
Traditional AI-based models have several major challenges when predicting the strength and load-displacement responses of concrete-filled steel tube (CFST) columns. These include unclear correlation between the inherent structural properties and the displacement, significant computational cost, and lack of ability to predict different types of CFST members. To address these, this study proposes a novel Cross-LSTM model for predicting the behavior and strength of concrete-filled steel tube columns. The model first leverages a cross-attention mechanism to capture the complex relationship between the displacement and the strength, and then uses a long short-term memory (LSTM) network to predict the full load-displacement curve. It also includes a component identifier in the input features, allowing the model to distinguish and predict conventional CFST members and CFST members made of stainless steel tube. The accuracy of the proposed model was verified by comparing its predictions with the strength and load-displacement curves obtained from experimental tests and finite element analyses.
{"title":"A novel cross-LSTM model for predicting the behavior and strength of concrete-filled steel tube columns","authors":"Zhichao Lai, Shiji Zhang, Deren Lu","doi":"10.1016/j.engstruct.2026.122221","DOIUrl":"10.1016/j.engstruct.2026.122221","url":null,"abstract":"<div><div>Traditional AI-based models have several major challenges when predicting the strength and load-displacement responses of concrete-filled steel tube (CFST) columns. These include unclear correlation between the inherent structural properties and the displacement, significant computational cost, and lack of ability to predict different types of CFST members. To address these, this study proposes a novel Cross-LSTM model for predicting the behavior and strength of concrete-filled steel tube columns. The model first leverages a cross-attention mechanism to capture the complex relationship between the displacement and the strength, and then uses a long short-term memory (LSTM) network to predict the full load-displacement curve. It also includes a component identifier in the input features, allowing the model to distinguish and predict conventional CFST members and CFST members made of stainless steel tube. The accuracy of the proposed model was verified by comparing its predictions with the strength and load-displacement curves obtained from experimental tests and finite element analyses.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122221"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036945","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 : 2026-04-15Epub Date: 2026-01-23DOI: 10.1016/j.engstruct.2026.122201
Henrieke Fritz , David Trujillo , Matthias Kraus
The structural stability of axially compressed members is essential for the design of safe and efficient load-bearing systems. Within sustainable construction, bamboo has emerged as a promising renewable building material due to its high specific strength and low environmental impact. However, due to its natural anisotropy and geometric variability, the buckling behaviour of bamboo differs significantly from that of conventional isotropic materials. This study presents experimental investigations of flexural buckling in full-scale bamboo culms with intermediate and high slenderness ratios. After a concise review of theoretical approaches for predicting buckling capacities, the experimental methodology of the present study is described, including specimen preparations, test setups, and boundary conditions of the experimental studies. The experimental results are then analysed to assess load-displacement behaviour, the influence of initial imperfections, and correlations between material as well as geometric parameters and the flexural buckling capacities. Finally, existing methods for recalculating flexural buckling capacities, as well as the design method for axially loaded bamboo culms based on ISO 22156 are evaluated against the experimental results. The analysis indicates that ISO 22156 leads to overly conservative capacity estimates, failing to adequately reflect the load-bearing performance of long, slender bamboo culms and demonstrating a significant variation in safety margins across different slendernesses. The findings of this study highlight the need to revise current design methods to ensure the safe use of bamboo as a structural material and to strengthen engineers’ confidence in its use.
{"title":"An experimental study on the structural stability and buckling behaviour of slender bamboo culms","authors":"Henrieke Fritz , David Trujillo , Matthias Kraus","doi":"10.1016/j.engstruct.2026.122201","DOIUrl":"10.1016/j.engstruct.2026.122201","url":null,"abstract":"<div><div>The structural stability of axially compressed members is essential for the design of safe and efficient load-bearing systems. Within sustainable construction, bamboo has emerged as a promising renewable building material due to its high specific strength and low environmental impact. However, due to its natural anisotropy and geometric variability, the buckling behaviour of bamboo differs significantly from that of conventional isotropic materials. This study presents experimental investigations of flexural buckling in full-scale bamboo culms with intermediate and high slenderness ratios. After a concise review of theoretical approaches for predicting buckling capacities, the experimental methodology of the present study is described, including specimen preparations, test setups, and boundary conditions of the experimental studies. The experimental results are then analysed to assess load-displacement behaviour, the influence of initial imperfections, and correlations between material as well as geometric parameters and the flexural buckling capacities. Finally, existing methods for recalculating flexural buckling capacities, as well as the design method for axially loaded bamboo culms based on ISO 22156 are evaluated against the experimental results. The analysis indicates that ISO 22156 leads to overly conservative capacity estimates, failing to adequately reflect the load-bearing performance of long, slender bamboo culms and demonstrating a significant variation in safety margins across different slendernesses. The findings of this study highlight the need to revise current design methods to ensure the safe use of bamboo as a structural material and to strengthen engineers’ confidence in its use.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122201"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036947","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 : 2026-04-15Epub Date: 2026-01-23DOI: 10.1016/j.engstruct.2026.122192
Abdelrahman Ahmed , Ashraf El Damatty , Ahmed El Ansary
As exposed structures, transmission lines (TL) are very vulnerable to collapse during extreme wind events. Failure incidents of TLs have been occurring frequently around the globe causing large economic losses and tremendous social distress. One of the extreme wind events that contributed to many failures of TLs is downbursts. Failure of a tower of a TL during a downburst can trigger a cascade-type of collapse to the adjacent towers of the line. This is because of the unbalanced conductor longitudinal force that a tower will experience after the failure of an adjacent tower. A typical TL system includes many tangent towers and a few end towers. These end towers are stronger structures and should be designed to contain the progression of the cascade failure. A numerical model was previously developed at the University of Western Ontario, Canada, aiming to study the behaviour and failure modes of TLs under downbursts. The model incorporates nonlinear finite element analysis of the towers, an analytical solution for the conductors, and downburst wind field obtained from Computational Fluid Dynamics (CFD) simulations. The model can perform the cascade failure analysis of multiple towers by predicting the failure shape of the towers and then calculating the conductors’ reactions transferred to the adjacent towers. In the current study, this numerical model is extended to include terminations towers, a type of end towers, in addition to tangent towers, allowing for the prediction of behaviour and failure mechanism of an entire segment of a TL bounded by two termination towers. Details of the numerical model enabling the incorporation of different types of towers with different conductors’ end-conditions are discussed in the paper. The model is able to identify the tangent tower at which failure will be initiated. The numerical code is designed to be compatible with the commercial software “PLS-TOWER”, which is widely used in the industry, providing a tool for practicing engineers to investigate the behaviour and cascade failure of an entire segment of a TL based on real conditions. A case study of a line segment is simulated using the developed model to study its progressive failure under downbursts. The study investigates the impact of different line properties on the progression of failure and on the behaviour of the termination towers.
{"title":"A system approach to study the cascade failure of transmission line segment under downbursts","authors":"Abdelrahman Ahmed , Ashraf El Damatty , Ahmed El Ansary","doi":"10.1016/j.engstruct.2026.122192","DOIUrl":"10.1016/j.engstruct.2026.122192","url":null,"abstract":"<div><div>As exposed structures, transmission lines (TL) are very vulnerable to collapse during extreme wind events. Failure incidents of TLs have been occurring frequently around the globe causing large economic losses and tremendous social distress. One of the extreme wind events that contributed to many failures of TLs is downbursts. Failure of a tower of a TL during a downburst can trigger a cascade-type of collapse to the adjacent towers of the line. This is because of the unbalanced conductor longitudinal force that a tower will experience after the failure of an adjacent tower. A typical TL system includes many tangent towers and a few end towers. These end towers are stronger structures and should be designed to contain the progression of the cascade failure. A numerical model was previously developed at the University of Western Ontario, Canada, aiming to study the behaviour and failure modes of TLs under downbursts. The model incorporates nonlinear finite element analysis of the towers, an analytical solution for the conductors, and downburst wind field obtained from Computational Fluid Dynamics (CFD) simulations. The model can perform the cascade failure analysis of multiple towers by predicting the failure shape of the towers and then calculating the conductors’ reactions transferred to the adjacent towers. In the current study, this numerical model is extended to include terminations towers, a type of end towers, in addition to tangent towers, allowing for the prediction of behaviour and failure mechanism of an entire segment of a TL bounded by two termination towers. Details of the numerical model enabling the incorporation of different types of towers with different conductors’ end-conditions are discussed in the paper. The model is able to identify the tangent tower at which failure will be initiated. The numerical code is designed to be compatible with the commercial software “PLS-TOWER”, which is widely used in the industry, providing a tool for practicing engineers to investigate the behaviour and cascade failure of an entire segment of a TL based on real conditions. A case study of a line segment is simulated using the developed model to study its progressive failure under downbursts. The study investigates the impact of different line properties on the progression of failure and on the behaviour of the termination towers.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122192"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036942","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 : 2026-04-15Epub 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":"2026-04-15","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}
Pub Date : 2026-04-15Epub Date: 2026-02-09DOI: 10.1016/j.engstruct.2026.122306
Yanbo Cao , Ge Yan , Yiming Cao , Dianlong Yu , Longqi Cai , Yu Wang , Yang Li , Wenming Zhang
This study focuses on the linear spectral vibration and multi-modal vibration mitigation of pipeline systems by using a single multi-stable nonlinear energy sink (MNES) which is critical for ship acoustic stealth. Methodologically, the finite element method is employed to construct a dynamic model of the pipeline system, subsequently analyzing an analysis of the system’s natural characteristics. Furthermore, an improved MNES configuration is proposed, the working mechanism of which achieves adaptive absorption of the broadband vibrations through potential well transitions, with its integration into the pipeline-MNES coupled system elaborated. To assess the MNES’s wideband vibration mitigation capability for the pipeline system, the genetic algorithm (GA) is employed to optimize the vibration-reduction parameters of MNES. Simulations have revealed that under fixed three-frequency base excitation, the suppressions of the MNES can reach 86.2 %, 81.7 %, and 80.6 % for the vibration transmission rate responses, the rates are 90.5 %, 87.3 %, and 98.9 % for the acceleration responses, the rates stand at 82.4 %, 81.7 %, and 80.5 % for the displacement responses, at 24 Hz, 48 Hz, and 120 Hz. Under sweep three-frequency base excitation, the MNES’s vibration suppressions for the vibration transmission rate responses are 82.7 %, 83.1 %, and 80.3 %, 82.4 %, 83.4 %, and 80.2 % for the acceleration responses, and 82.7 %, 83.3 %, and 80.4 % for the displacement responses, at 24 Hz, 48 Hz, and 120 Hz. A set of experiments are conducted to validate the reliability and engineering applicability. The findings are that under fixed three-frequency base excitation, the MNES achieves acceleration response suppressions of 88.3 %, 87.7 %, and 86.2 % at 24 Hz, 48 Hz, and 120 Hz. Under sweep single-frequency base excitation, a three-mode resonant vibration excitation, the suppressions for acceleration responses at 24 Hz, 45 Hz, and 107 Hz are 86.4 %, 84.7 %, and 83.5 %. Test results confirm that MNES exhibits robust broadband vibration damping performance for both linear spectral vibration and multi-modal vibration of pipeline systems.
{"title":"Linear spectral vibration and multi-modal vibration mitigation of pipeline systems using a multi-stable nonlinear energy sink","authors":"Yanbo Cao , Ge Yan , Yiming Cao , Dianlong Yu , Longqi Cai , Yu Wang , Yang Li , Wenming Zhang","doi":"10.1016/j.engstruct.2026.122306","DOIUrl":"10.1016/j.engstruct.2026.122306","url":null,"abstract":"<div><div>This study focuses on the linear spectral vibration and multi-modal vibration mitigation of pipeline systems by using a single multi-stable nonlinear energy sink (MNES) which is critical for ship acoustic stealth. Methodologically, the finite element method is employed to construct a dynamic model of the pipeline system, subsequently analyzing an analysis of the system’s natural characteristics. Furthermore, an improved MNES configuration is proposed, the working mechanism of which achieves adaptive absorption of the broadband vibrations through potential well transitions, with its integration into the pipeline-MNES coupled system elaborated. To assess the MNES’s wideband vibration mitigation capability for the pipeline system, the genetic algorithm (GA) is employed to optimize the vibration-reduction parameters of MNES. Simulations have revealed that under fixed three-frequency base excitation, the suppressions of the MNES can reach 86.2 %, 81.7 %, and 80.6 % for the vibration transmission rate responses, the rates are 90.5 %, 87.3 %, and 98.9 % for the acceleration responses, the rates stand at 82.4 %, 81.7 %, and 80.5 % for the displacement responses, at 24 Hz, 48 Hz, and 120 Hz. Under sweep three-frequency base excitation, the MNES’s vibration suppressions for the vibration transmission rate responses are 82.7 %, 83.1 %, and 80.3 %, 82.4 %, 83.4 %, and 80.2 % for the acceleration responses, and 82.7 %, 83.3 %, and 80.4 % for the displacement responses, at 24 Hz, 48 Hz, and 120 Hz. A set of experiments are conducted to validate the reliability and engineering applicability. The findings are that under fixed three-frequency base excitation, the MNES achieves acceleration response suppressions of 88.3 %, 87.7 %, and 86.2 % at 24 Hz, 48 Hz, and 120 Hz. Under sweep single-frequency base excitation, a three-mode resonant vibration excitation, the suppressions for acceleration responses at 24 Hz, 45 Hz, and 107 Hz are 86.4 %, 84.7 %, and 83.5 %. Test results confirm that MNES exhibits robust broadband vibration damping performance for both linear spectral vibration and multi-modal vibration of pipeline systems.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122306"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185240","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 : 2026-04-15Epub Date: 2026-01-22DOI: 10.1016/j.engstruct.2026.122197
Chunxiao Ning, Yazhou Xie
Predicting region-wide structural responses under seismic shaking is essential for enhancing the effectiveness of earthquake engineering tasks such as earthquake early warning and regional seismic risk and resilience assessments. Existing domain-specific and data-driven approaches, however, lack the capability to provide high-fidelity, structure-specific dynamic response predictions for large-scale structural inventories in a timely manner, especially when structural parameters and detailing are incomplete or unavailable. To address this gap, this study developed a deep learning framework, which integrates heterogeneous ground motion sequences and partial structural information as model inputs, to predict structure-specific, probabilistic dynamic responses of regional structural portfolios. Validation on a portfolio of highway bridges in California demonstrates the model’s ability to capture inter-structure response variability by inputting critical and accessible bridge parameters while accounting for uncertainties due to the lack of other information. The results underscore the framework’s efficiency and accuracy, paving the way for various advancements in performance-based earthquake engineering and regional-scale seismic decision-making.
{"title":"Surrogate structure-specific probabilistic dynamic responses of bridge portfolios using deep learning with partial information","authors":"Chunxiao Ning, Yazhou Xie","doi":"10.1016/j.engstruct.2026.122197","DOIUrl":"10.1016/j.engstruct.2026.122197","url":null,"abstract":"<div><div>Predicting region-wide structural responses under seismic shaking is essential for enhancing the effectiveness of earthquake engineering tasks such as earthquake early warning and regional seismic risk and resilience assessments. Existing domain-specific and data-driven approaches, however, lack the capability to provide high-fidelity, structure-specific dynamic response predictions for large-scale structural inventories in a timely manner, especially when structural parameters and detailing are incomplete or unavailable. To address this gap, this study developed a deep learning framework, which integrates heterogeneous ground motion sequences and partial structural information as model inputs, to predict structure-specific, probabilistic dynamic responses of regional structural portfolios. Validation on a portfolio of highway bridges in California demonstrates the model’s ability to capture inter-structure response variability by inputting critical and accessible bridge parameters while accounting for uncertainties due to the lack of other information. The results underscore the framework’s efficiency and accuracy, paving the way for various advancements in performance-based earthquake engineering and regional-scale seismic decision-making.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"353 ","pages":"Article 122197"},"PeriodicalIF":6.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036858","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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