Structures最新文献

{"title":"A non-iterative method to analyze long term behavior of prestressed concrete beams with reinforcement","authors":"Thittarashmi Mallick ,&nbsp;U. Saravanan ,&nbsp;Mary Williams","doi":"10.1016/j.istruc.2026.111197","DOIUrl":"10.1016/j.istruc.2026.111197","url":null,"abstract":"<div><div>The present study proposes a non-iterative method to investigate the time-dependent behavior of layered viscoelastic bodies with application to prestressed concrete (PSC) beams considering the effect of reinforcement. The layered viscoelastic body is subjected to bidirectional moments and an axial force. The axial force arises due to the stretching and clamping of a tendon to the beam (applied prestress force), and the biaxial bending moments develop due to either biaxial eccentricities in the location of the tendons or asymmetrical loading or both. Though the tendon could be bonded or unbonded to the beam, a perfect bond between concrete and reinforcement is assumed. Different layers are further assumed to shrink over time differently. This shrinkage phenomenon is modeled by changing the undeformed length of the layers in the beam with time. The observed axial strain, by virtue of it being small, is additively decomposed into shrinkage and mechanical strain. Due to the presence of axial force, the PSC beams are idealized as beam-column. The viscoelastic beam-column boundary value problem is solved through the Laplace transform technique. Hence, the present approach is generalized enough to include any viscoelastic model represented in the integral form. The proposed method is validated using experimental data for both bonded and unbonded prestressed concrete beams. The validated model is used to highlight the need for considering the reinforcement wherein the deflection could increase or decrease depending on the location and percentage of reinforcement by even as much as 3 times.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111197"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192369","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}

{"title":"Fatigue life assessment of multi-span railway masonry arch bridges based on crack growth rate","authors":"Mahdi Yazdani,&nbsp;René Panian","doi":"10.1016/j.istruc.2026.111311","DOIUrl":"10.1016/j.istruc.2026.111311","url":null,"abstract":"<div><div>Masonry arch bridges, as critical components of railway infrastructure, are widely scattered throughout the Iranian railway network. Although most of these bridges have been in service for over ninety years, they continue to perform safely while being subjected to increasing traffic demands in recent years. Existing assessment methods mainly focus on ultimate load capacity and do not explicitly address fatigue damage or remaining service life under repeated train loading. Unlike conventional capacity-based approaches, this study presents a fracture-mechanics-based framework that explicitly accounts for fatigue crack growth, enabling quantitative prediction of the remaining service life of masonry arch bridges, which has rarely been addressed in existing numerical studies. A detailed finite element model was developed in ANSYS and calibrated using crack mouth opening displacement (CMOD) measurements obtained from field observations. Fatigue crack propagation was considered by Paris’ law, enabling the relationship between crack length, stress intensity factor (SIF), and number of load cycles to be quantified under realistic traffic scenarios. The results show that for an axle load of 20 ton and 15 train passages per day, the estimated fatigue life of the bridge is approximately 125 years, which decreases to about 94 years when the axle load increases to 25 ton. Based on the critical load position at one-quarter of the main span, a fatigue limit of approximately 0.27 was identified. The proposed methodology extends conventional assessment practices by integrating fracture-mechanics-based fatigue analysis into numerical modeling, providing a practical and service-life-oriented tool for predicting fatigue life and supporting informed decision-making in the structural management of historic railway masonry arch bridges.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111311"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192526","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}

{"title":"Performance-based seismic evaluation and machine learning prediction of damage index for externally strengthened reinforced concrete columns with high-performance fiber composite laminates","authors":"Yang Chan,&nbsp;Yan Liu,&nbsp;K. Jasim M.,&nbsp;C. Sheng Shao,&nbsp;H.E. Hosiny A.,&nbsp;Sami E. Atar,&nbsp;J. Escorca G","doi":"10.1016/j.istruc.2026.111093","DOIUrl":"10.1016/j.istruc.2026.111093","url":null,"abstract":"<div><div>This study examines the cyclic behavior and seismic damage progression of Reinforced Concrete (RC) columns reinforced with steel bars and externally strengthened using High-Performance Fiber Composite (HPFC) laminates as Synthetic Fiber Composite (SFC) bands. The columns were tested under constant axial load and reversed cyclic lateral displacement. Key variables included the level of HPFC reinforcement ranging from 0 % to 25 % vertical band coverage in the plastic hinge region and the effective column length with short and tall configurations. Results indicated that 25 % HPFC reinforcement increased lateral load capacity by up to 40 % and nearly doubled the dissipated hysteretic energy. The dissipated energy increased from 1080 kN·mm to 2260 kN·mm. Additionally, drift capacity improved from approximately 1.8–2.0 % to 3.2–3.5 % at 20 % post-peak strength loss. Residual drifts for short columns remained low, indicating minimal permanent deformation in relation to the enhanced strength and energy dissipation. Shorter columns demonstrated greater reinforcement effectiveness, with plasticity localized in the externally reinforced region, while taller columns exhibited more distributed cracking and flexural deformation. A Structural Reinforcement Efficiency Factor (SREF), which combines normalized peak strength, ultimate drift, and dissipated energy, was introduced. The SREF values were slightly higher for short columns compared to tall ones. A hybrid artificial neural network support vector machine (ANN-SVM) model, based on the experimental data, achieved a Coefficient of Determination (R²) of 0.89, a Root Mean Square Error (RMSE) of 0.18, and a Mean Absolute Error (MAE) of 0.13, effectively predicting the modified Park Ang Damage Index (DI). This integrated AI-based framework provides a valuable tool for performance-based seismic design and retrofit optimization of HPFC strengthened RC columns.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111093"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192592","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}

{"title":"Accurate prediction of bridge deflection based on spatiotemporal feature mining using a T-BiLSTM-L model","authors":"Shiyang Xu ,&nbsp;Youliang Ding ,&nbsp;Fangfang Geng ,&nbsp;Kang Yang","doi":"10.1016/j.istruc.2026.111270","DOIUrl":"10.1016/j.istruc.2026.111270","url":null,"abstract":"<div><div>Bridges, as critical infrastructure in transportation systems, require health monitoring and maintenance to ensure traffic safety. Deflection changes serve as an essential indicator for evaluating the health condition of bridges, which are influenced by various factors such as temperature, humidity, and load. Traditional methods of bridge deflection monitoring often rely heavily on temperature data, neglecting the coupling effects of multiple factors, leading to insufficient accuracy in long-term deflection predictions. This study proposes a bridge deflection prediction method based on spatio-temporal features, integrating multiple deep learning models to achieve accurate predictions. The relationship between bridge deflection and factors such as temperature and humidity is first analyzed, highlighting that the correlation between temperature and deflection varies at different locations, thus illustrating the impact of multi-factor coupling on deflection changes. Based on this analysis, machine learning models such as XGBoost, GRU, LSTM, and Transformer are introduced to explore deflection prediction methods using temperature and historical deflection data. Furthermore, by incorporating multi-time and spatial features, experimental results show that LSTM and GRU models outperform others in processing long-duration spatio-temporal data, demonstrating higher prediction accuracy and stability. To further enhance prediction performance, a T-BiLSTM-L hybrid model is designed, which optimizes deflection prediction through linear replacement and achieves breakthroughs in various evaluation metrics. Experimental results demonstrate that the T-BiLSTM-L model shows high accuracy and strong generalization ability when predicting deflection at different locations and for different forecast horizons. The RMSE values range from 0.455 to 0.797, and the R² values consistently exceed 0.96, achieving up to an 85.4 % improvement over traditional models. In conclusion, the proposed T-BiLSTM-L model effectively captures the spatio-temporal evolution of bridge deflection, demonstrating strong adaptability and robustness. This method not only provides a high-precision deflection prediction tool for existing bridge health monitoring systems but also offers a theoretical basis and technical support for the future development of bridge health management and early warning systems.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111270"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192119","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}

{"title":"Mechanical properties of graphite tailings ultra-high-performance concrete for prefabricated building joints in cold regions","authors":"Zi-Xuan Han,&nbsp;Ben Li,&nbsp;Qing-Qing Ma,&nbsp;Lin-Yang Liu,&nbsp;Shu-Yi Fan","doi":"10.1016/j.istruc.2026.111368","DOIUrl":"10.1016/j.istruc.2026.111368","url":null,"abstract":"<div><div>This research investigates mechanical properties of graphite tailings ultra-high-performance concrete (GT-UHPC) for prefabricated building joints in cold regions, aiming to address technical bottlenecks of high cost and harsh curing conditions in conventional UHPC applications. By partially replacing river sand with size-classified graphite tailings, this research systematically explores effects of replacement rates on basic physical properties, static/dynamic mechanical performance, thermal stability, hydration products and microstructure of GT-UHPC. GT-UHPC-30 (30 % content) exhibits optimal performance, 28-day compressive strength is 139.20 MPa, flexural strength is 24.74 MPa and elastic modulus is 39.18 GPa, with significantly enhanced impact resistance under high-pressure loading (162.75 MPa at 6 bar). Microstructurally, moderate graphite tailings promote hydration reactions, optimize pore distribution with reducing macropores and increasing gel pores, and strengthen interfacial transition zone. Economically, GT-UHPC-30 reduces material costs by 20.23 % and carbon emissions by 16.98 %. This research provides theoretical support for design and engineering application of high-performance prefabricated joint materials in cold regions.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111368"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192040","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}

{"title":"A life-cycle cost-based optimization framework for seismic design of structures using FEMA P-58 and the SAR algorithm","authors":"Amir Shabani ,&nbsp;Behrouz Asgarian ,&nbsp;Mehrdad Aftabiazar","doi":"10.1016/j.istruc.2026.111278","DOIUrl":"10.1016/j.istruc.2026.111278","url":null,"abstract":"<div><div>This study presents a life-cycle cost-based optimization framework for the seismic design of structures, developed within the second generation of the Performance-Based Earthquake Engineering (PBEE-2) methodology. The design problem was formulated as a single-objective optimization to minimize life-cycle cost. To reduce the high computational demand of nonlinear analyses required for seismic loss estimation, an approximate loss estimation method was developed based on the story-based method and FEMA P-58. Additionally, a new constraint-handling method was presented, which reduces computational cost by more than 80 % compared with the conventional penalty function method. It requires no parameter tuning and can be implemented with any optimization algorithm. The framework’s effectiveness was demonstrated through the optimal design of a three-dimensional five-story steel moment-resisting frame, with direct comparisons to a conventional design approach. The results reveal that these optimized structures not only achieved approximately 20 % reductions in both structural weight and expected seismic loss, but also showed lower probabilities of collapse. These designs also exhibited increased stiffness, strength, and ductility. The performance of several metaheuristic algorithms was compared for solving the optimization problem, and among the studied algorithms, the SAR algorithm demonstrated superior performance, providing more effective optimization results. The effect of member grouping on the optimal design was also investigated. Overall, the proposed framework provides a practical and computationally efficient tool for life-cycle cost optimization within PBEE-2.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111278"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192350","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}

{"title":"Identification of soil-structure interaction as the primary source of traffic-induced vibrations in a low-rise building: A nonlinear-elastic perspective","authors":"Fabián Consuegra","doi":"10.1016/j.istruc.2026.111228","DOIUrl":"10.1016/j.istruc.2026.111228","url":null,"abstract":"<div><div>Soil-Structure Interaction (SSI) effects may become significant for buildings situated on soft soil when coupled with specific foundation and superstructure flexibility characteristics. Under service conditions, traffic-induced waves can cause vibrations perceptible to building occupants, even when the structure fully complies with a conventional strength-based building standard. This investigation was based on records of a six-story building. Soil foundation was modeled through a semi-infinite elastic media representation. A calibrated model achieved estimations within an 8 % difference from actual field records. The results demonstrate that SSI induces a reduction of up to 40 % in the system’s lateral stiffness during its service state at overall drift ratios of about 0.0002 %. In contrast to research approaches focused primarily on inelastic behavior for seismic applications, this study presents a methodology to identify the presence of SSI, by tracking the frequency of an equivalent nonlinear-elastic model. This variation occurs as base movement activates foundation flexibility, leading to the coexistence of two distinct fundamental frequencies. The identification is achieved through a 2-DOF representation and it involves (a) analyzing the frequency content of ambient vibrations recorded with high-sensitivity instrumentation; (b) tracking the fundamental frequency as a function of displacement; (c) establishing a linear transfer function (TF) to isolate the effects of soil flexibility; and (d) comparing estimated forces applied at each DOF to localize the source of energy input. The method was successfully implemented to characterize the most probable scenario causing user-perceived vibrations. Despite its efficacy, the applicability of this approach may be limited in cases with low signal-to-noise ratios or highly rigid superstructures that preclude the coexistence of the fixed-base and SSI-influenced frequencies.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111228"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192527","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}

{"title":"Compressive behaviour of GFRP tubes with concrete protection after exposure in elevated temperatures","authors":"Jian Song Yuan ,&nbsp;Haitang Zhu ,&nbsp;Yan Zhuge ,&nbsp;Yu Zhang ,&nbsp;Jianan Guan ,&nbsp;Jun-Jie Zeng","doi":"10.1016/j.istruc.2026.111366","DOIUrl":"10.1016/j.istruc.2026.111366","url":null,"abstract":"<div><div>Enhancing the fire resistance of the pultruded glass fiber reinforced polymer (GFRP) composites is critical for their safe and reliable use in engineering applications. The study experimentally evaluates the influence of concrete cover on the compressive behaviour of GFRP tubes after exposure to elevated temperatures. A total of 92 GFRP tubes were tested with three types of concrete protection, namely internal concrete, external concrete and dual-side concrete, under exposure to elevated temperatures of 250 ℃, 300 ℃, and 350 ℃ for duration of 30, 60, and 90 min. The post-heat bond-slip behaviour between the infilled concrete and GFRP tubes was investigated using push-out tests, revealing improved bonding due to surface roughening from resin decomposition. Subsequently, compression tests were performed after exposure, demonstrating that concrete protection is an effective and practical method for safeguarding GFRP tubes against elevated temperatures. Owing to effective oxygen isolation, the GFRP tubes with dual-side and external protection exhibited more than 88 % of their original strength even after exposure to 350 °C for 60 min. Additionally, a thin concrete cover (approximately 25 mm) provided sufficient protection, and when GFRP tubes were well protected, exposure duration had a negligible effect on the compressive behaviour.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111366"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191397","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}

{"title":"Study on the bonding characteristics and mechanism of the interface between ultra-high-performance concrete and normal concrete under varying substrate moisture contents","authors":"Ruize Li ,&nbsp;Wen Sun ,&nbsp;Jiaze Wang ,&nbsp;Shumin Zhan ,&nbsp;Jiangjiang Zhang ,&nbsp;Yanhua Yang","doi":"10.1016/j.istruc.2026.111370","DOIUrl":"10.1016/j.istruc.2026.111370","url":null,"abstract":"<div><div>This study investigates how the moisture content of the substrate affects the bonding characteristics at the interface of ultra-high performance concrete (UHPC) and normal concrete (NC). The strength of the bonding at the interface was evaluated using slant shear and splitting tensile tests. The correlation between the NC residual bonding area (NRBA) and splitting tensile strength on the damaged surface of the restored specimens was examined by digital image processing. The microstructure of the overlay transition zone (OTZ) at the UHPC-NC interface was quantitatively analyzed utilizing SEM. Finally, MD simulations were integrated with macro-microscopic tests to assess the impact of varying substrate moisture contents (0 %, 25 %, 50 %, 75 %, and 100 %) on the bonding characteristics of the UHPC-NC interface and to speculate the underlying bonding mechanism. The findings showed that the splitting tensile strength and NRBA followed the same change trend as the moisture content of the substrate rose, and they were positively correlated. Substrate moisture content of 50–75 % significantly enhanced the bonding characteristics of the UHPC-NC interface, whereas insufficient or excessive moisture content was detrimental to the development of bonding strength. The augmentation of substrate moisture content facilitated the hydration reaction and volcanic ash reaction in UHPC, and the mechanical interlocking and chemical bonding among crystals inhibited the formation of interfacial fissures, which was the primary reason for enhancing bonding characteristics. Excessive substrate moisture content (100 %) results in an increase in interfacial pores and diminishes bonding characteristics.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111370"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191457","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}

{"title":"Experimental study on the lateral structural mechanical performance of Tang dynasty palace-style timber frame","authors":"Juan Wang ,&nbsp;Zhiwei Chen ,&nbsp;Zhihan Cui ,&nbsp;Xuechun Wang","doi":"10.1016/j.istruc.2026.111285","DOIUrl":"10.1016/j.istruc.2026.111285","url":null,"abstract":"<div><div>The Tang dynasty palace-style timber frame exhibits a unique and intricate structural design, representing exceptionally valuable cultural relics among China's ancient architectural heritage. This type of timber frame is composed of three horizontal layered components stacked vertically - the column, bracket complexes (puzuo layer), and roof truss - which are vertically stacked from bottom to top through meticulously crafted mortise-and-tenon joints. This architectural form, having endured for over a millennium while remaining well-preserved, holds profound historical, cultural, and scientific research significance. To better assess the mechanical properties of the palace-style timber structure in the Tang dynasty, a quasi-static test was carried out on a 1:3 scaled model of a single-span model of the palace-style timber frame in the Tang dynasty. The deformation characteristics, failure mechanisms, hysteretic characteristics, lateral stiffness and energy consumption characteristics of the timber frame were systematically studied. The test results show that the main deformation of the timber frame is the rotation, raising and rocking of the timber column; the shear deformation for the bracket complexes is not significant; and the load displacement hysteretic curve of the loading points of the timber frame is bow shaped, with a pinching effect. The initial lateral stiffness of the timber frame is large, and the degradation of the stiffness is significant after yielding. The energy consumption of the timber frame is mainly generated through the repeated rocking of the timber column and the friction sliding and shear deformation between components.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111285"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191401","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}