Engineering Structures最新文献

{"title":"Consistent thermodynamics analysis of restrained steel columns in fire – Part 1: Theoretical developments for general application","authors":"Pedro Dias Simão ,&nbsp;João Paulo C. Rodrigues","doi":"10.1016/j.engstruct.2025.120591","DOIUrl":"10.1016/j.engstruct.2025.120591","url":null,"abstract":"<div><div>The present paper proposes a novel way to describe the behaviour of restrained steel columns in fire. It is based on the fundamental concepts of <em>Engineering Thermodynamics</em>. Energy and entropy-based quantities are combined to provide an additional link between the thermal and the thermomechanical problems involved in the process, during the relevant period for structural engineers, that is between the ignition instant and the instant when the column collapses. The Thermodynamics analysis is made here at a macroscopic level and the passage to the particle’s level is made by means of the adequate mathematical tools, such as the Gauss’s <em>Theorem of Divergence</em>. In opposition to the traditional <em>Clausius-Duhem</em> formula, the description clearly distinguishes between external work and internal strain energy. An adequate structural model is adopted for the column, to take into account the interactions between the column and the surrounding frame. The structural behaviour of steel columns in fire is a sequence of two mechanical phenomena: thermal buckling followed by plastic collapse. It involves an energy transfer between a heat source, that is the fire that occurs at the column’s compartment due to any reason beyond our concern, and the thermal sinks, in this case the column itself and the surrounding frame. The proposed methodology proposes a novel way to treat the large data that arises from any sophisticated numerical methodology usually adopted in structural engineering. This means that it is supposed that the structural analysis is already performed, and we focus on the treatment of the information that arises from the structural analyses, to provide a better description of the involved phenomena and to pave the way to novel design strategies, based on the energy absorption capacity of frames during fire. This work is devoted solely to the theoretical developments for general application. A complementary paper applies the concepts and strategies developed here to real illustrative examples, in the context of the <em>voxels-based Rayleigh-Ritz method</em>, and confirms all statements presented in the present work.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120591"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084742","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}

{"title":"Experiments on local buckling of cold-formed steel lipped channels in compression at elevated temperatures","authors":"Jiangyue Xie,&nbsp;Yu Niu,&nbsp;Thomas Gernay","doi":"10.1016/j.engstruct.2025.120594","DOIUrl":"10.1016/j.engstruct.2025.120594","url":null,"abstract":"<div><div>Cold-formed steel members are widely used in buildings, making it essential to understand their behavior under fire. While extensive research at ambient temperature has led to design methods advancing the use of cold-formed steel load bearing systems, there is still a lack of understanding on the effects of elevated temperatures on the buckling behavior of these thin-walled members, which has hindered the development of fire design methods. This study presents a series of steady-state tests to evaluate the strength and stability of short cold-formed steel lipped channels in compression at uniform elevated temperatures. A novel test rig based on a customizable furnace frame and electrical ceramic heating pads was designed to conduct the experiments, showing high repeatability and accurate control of the steel temperature distribution. Coupon tests were conducted to obtain the elevated temperature material properties, which were compared with provisions in standards. The lipped channels exhibited local buckling of the web, with some specimens also displaying distortional buckling. The channels retained about 88 % of their strength at 300°C but only 34 % at 600°C. Strength evaluations with shell finite element analysis and with the Direct Strength Method led to conservative predictions. This study advances understanding of local buckling behavior for development of performance-based structural fire design methods for cold-formed steel-framed structures.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120594"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084745","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}

{"title":"Calibrating frequency-independent soil–foundation parameters for time-domain substructure soil–structure interaction analysis","authors":"Abdelrahman Taha ,&nbsp;Farid Ghahari ,&nbsp;Hamed Ebrahimian ,&nbsp;Ramin Motamed ,&nbsp;Farzad Naeim","doi":"10.1016/j.engstruct.2025.120509","DOIUrl":"10.1016/j.engstruct.2025.120509","url":null,"abstract":"<div><div>This study introduces a framework for deriving calibrated frequency-independent soil-foundation (CFISF) parameters for time-domain substructure soil-structure interaction (SSI) analysis. While various time-domain approximations of the frequency-dependent impedance function have been proposed to facilitate SSI consideration in seismic analysis and design, their practical implementation often faces a critical trade-off: oversimplification compromises accuracy, while excessive complexity hinders practical application. To resolve this limitation, we propose a framework to derive CFISF parameters that can accurately simulate the time-domain response of soil-structure systems while maintaining ease of implementation. The framework comprises three key steps. First, dimensional analysis establishes the functional forms of the relationships linking the CFISF parameters to the soil-structure system parameters. Second, a Bayesian model inversion technique is employed to estimate CFISF parameters for a broad range of soil-structure model configurations, generating a comprehensive dataset of soil-structure model parameters and their corresponding estimated CFISF parameters. This step involves: (1) simulating the time-domain soil-structure system response under white-noise excitation using the direct approach, which serves as the ground truth, and (2) estimating the CFISF parameters by minimizing discrepancies between the direct and substructure model responses. Third, regression analysis is applied to the dataset to determine the unknown coefficients of the functional forms derived from dimensional analysis, yielding explicit equations for the CFISF parameters. To evaluate the performance of CFISF parameters beyond the calibration dataset, we conducted an assessment study on four soil-structure systems with varying geometries and material properties. The results demonstrate that the CFISF parameters enable substructure models to closely replicate direct model responses, outperforming traditional time-domain impedance function approximations. This framework equips the practicing community with a reliable tool for incorporating SSI effects into seismic design, enhancing both the accuracy and efficiency of SSI modeling and analysis.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120509"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084730","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}

{"title":"Experimental and numerical investigation of freeze-thaw damaged RC beams subject to impact loading","authors":"Xiguang Liu ,&nbsp;Weihang Tan ,&nbsp;Sailin Xu ,&nbsp;Yao Lv ,&nbsp;Ditao Niu ,&nbsp;Hussam N. Mahmoud","doi":"10.1016/j.engstruct.2025.120545","DOIUrl":"10.1016/j.engstruct.2025.120545","url":null,"abstract":"<div><div>The degradation of concrete mechanical properties induced by freeze-thaw cycles (FTCs) reduces bridge load-bearing capacity, prompting much concern about their impact on dynamic behavior. Drop-weight impact tests on freeze-thaw damaged reinforced concrete (RC) beams were conducted, and failure mechanisms and impact resistance were investigated. Considering the non-uniform degradation of concrete mechanical properties, caused by freeze-thaw damage gradients at different depths, a three-dimensional nonlinear finite element model for RC beams under impact loads was established. Using the validated model, the effects of the number of FTCs, impact velocities, reinforcement ratios, and stirrup ratios on the impact resistance performance of the beam subjected to FTCs were explored. As the degree of freeze-thaw damage increased and impact velocity rose, the failure mode of RC beams became more transitioned from flexural to shear failure. The effectiveness of increasing the stirrup ratio gradually decreased with the increase in the number of FTCs. Increasing the reinforcement ratio reduced the extent of stress damage at the top of the beam, but provided a limited increase to the local stiffness of freeze-thaw damaged RC beams.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120545"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090701","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}

{"title":"DIMMC: A 3D vision approach for structural displacement measurement using a moving camera","authors":"Yanda Shao ,&nbsp;Ling Li ,&nbsp;Jun Li ,&nbsp;Qilin Li ,&nbsp;Senjian An ,&nbsp;Hong Hao","doi":"10.1016/j.engstruct.2025.120566","DOIUrl":"10.1016/j.engstruct.2025.120566","url":null,"abstract":"<div><div>Structural displacement is an essential data for engineers to evaluate the health and safety of civil structures. Computer vision-based displacement measurement has become increasingly popular due to accessibility and cost-effectiveness. While most of the studies in this area have been focused on analysing footage taken by static cameras, the usage of moving cameras such as those mounted on Unmanned Aerial Vehicles (UAVs) presents a transformative opportunity for structural health monitoring (SHM). Moving cameras enable flexible and scalable displacement measurement, allowing inspections in hard-to-reach areas without the constraints of fixed installation points. This paper proposes a deep learning-based, purely computer vision system that requires no auxiliary devices, for measuring structural displacement using monocular footage from a single moving camera. This system utilizes a Vision Transformer (ViT)-based mesh deformation neural network to reconstruct 3D geometry from a single image. State-of-the-art deep learning models for object segmentation and tracking are also used to isolate relevant objects from the background. To convert the reconstructed coordinate system into real-world coordinates, a 3D point registration method is introduced. The system eliminates the need for installing artificial targets or detecting key points on the structure, enhancing the robustness of the measurement process. The effectiveness and accuracy of the proposed approach are verified through experimental tests on beam-shaped structures, with cross-correlation coefficients exceeding 0.97 and mean absolute percentage errors remaining below 33 % for dynamic test. These findings underscore the accuracy of the proposed approach and its promising potential for practical applications.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120566"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090703","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}

{"title":"A stochastic gradient online learning and prediction method for accelerating structural topology optimization using recurrent neural network","authors":"Yi Xing,&nbsp;Liyong Tong","doi":"10.1016/j.engstruct.2025.120507","DOIUrl":"10.1016/j.engstruct.2025.120507","url":null,"abstract":"<div><div>This study presents a new stochastic gradient online learning and prediction (SGoLap) method for accelerating structural topology optimization. The new method utilizes a one-hidden-layer recurrent neural network (RNN) to learn and predict online derivative information, including the second-order derivative of the objective function, in conjunction with an online learning and prediction strategy, and saves total computational time by selectively skipping FEA and sensitivity analysis steps. In the training module, a stochastic sampling scheme is proposed to reduce the size of training datasets and the number of RNN parameters. In addition to using gradient information, the SGoLap is applied to an approximated and vectorized Hessian matrix to account for contribution of second-order derivative in design variable update and to further reduce computational time. The present numerical results of solving 2D and 3D topology optimization problems demonstrate that the implementation of SGoLap can save up to 99.3 % and 90.9 % of the total computational time respectively.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120507"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084744","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}

{"title":"Local buckling of stainless steel stub columns with novel octagonal hollow sections","authors":"Yukai Zhong ,&nbsp;Ke Jiang ,&nbsp;Man-Tai Chen ,&nbsp;Andi Su ,&nbsp;Ou Zhao","doi":"10.1016/j.engstruct.2025.120512","DOIUrl":"10.1016/j.engstruct.2025.120512","url":null,"abstract":"<div><div>Octagonal hollow section, a novel type of polygonal hollow sections, combines the advantages of traditional circular and rectangular hollow sections while mitigating their limitations, with higher load-carrying capacities over rectangular hollow sections due to smaller plate element widths and better constructability over circular hollow sections owing to multiple flat faces providing operation platforms for welded and bolted connections. The present paper reports experimental and numerical studies on the local buckling behaviour of stainless steel octagonal hollow sections under axial compression. The testing programme included axial compression tests on fifteen stainless steel octagonal hollow section stub column specimens with five different outer cross-section dimensions and three different wall thicknesses, as well as tensile coupon tests and initial local geometric imperfection measurements. In parallel with the testing programme, a numerical modelling programme was carried out, with finite element models developed and validated against the test results and afterwards adopted to carry out parametric studies. The test and numerical data were used to evaluate the applicability of relevant design rules, as specified in the European code, American specification and ASCE standard, to stainless steel octagonal hollow sections. The evaluation results generally revealed that (i) the three sets of codified slenderness limits were unsafe when used for cross-section classification of stainless steel hexagonal hollow sections, (ii) the European code and American specification resulted in overall accurate and consistent cross-section compression resistance predictions for stainless steel octagonal hollow sections, but still with some overly conservative predictions for non-slender cross-sections and slightly unsafe predictions for those at the boundary of non-slender and slender cross-sections, and (iii) the ASCE standard provided overall scattered and inaccurate cross-section compression resistance predictions. Finally, improved slenderness limits for the three considered design codes and a revised ASCE design approach for predicting cross-section compression resistances were proposed.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"338 ","pages":"Article 120512"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084740","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}

{"title":"A machine learning approach for predicting a full load-deflection behaviour of strengthened beams using fabric-reinforced cementitious matrix (FRCM)","authors":"Kambiz Daneshvar,&nbsp;Mohammad Javad Moradi,&nbsp;Hamzeh Hajiloo","doi":"10.1016/j.engstruct.2025.120580","DOIUrl":"10.1016/j.engstruct.2025.120580","url":null,"abstract":"<div><div>Machine learning (ML) methods in structural engineering are typically applied to predict single values, such as failure load. This study presents an advanced application of ML by predicting five critical points on the load-deflection curve of fabric-reinforced cementitious matrix (FRCM)-strengthened rectangular beams. Three separate ML models were developed, each tailored to predict specific key points on the curve. The ML models consider variables such as mechanical and geometric properties of a beam, steel reinforcement, and the FRCM properties such as nominal thickness, number of layers, type of fabric and presence of anchorage. Based on these models, a user-friendly application was developed. In the second part of this study, validated Finite Element (FE) models examine the robustness of ML models on unseen data. The accuracy of the load-deflection curves is evaluated using three parameters: load capacity, stiffness, and absorbed energy. Results indicate that the proposed ML-based models effectively capture the entire response of FRCM-strengthened beams, achieving RMSE of 15 kN, 6 kN/mm, and 2kN-m for load capacity, stiffness, and absorbed energy, respectively.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"337 ","pages":"Article 120580"},"PeriodicalIF":5.6,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144071678","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}

{"title":"Wake-induced vibrations of tandem main cables: Insights from flexible and rigid models in wind tunnel tests","authors":"Jun Xu ,&nbsp;Hao-Yang Li ,&nbsp;Tai-Ke Zhang ,&nbsp;Cun-Ming Ma ,&nbsp;Cheng Pei ,&nbsp;Qing-Song Duan","doi":"10.1016/j.engstruct.2025.120495","DOIUrl":"10.1016/j.engstruct.2025.120495","url":null,"abstract":"<div><div>In order to accommodate the increasing span lengths of suspension bridges, the scheme of adopting tandem main cables was proposed. To provide valuable insights into the wake-induced vibration (WIV) characteristics of tandem main cables with variable center-to-center spacings from the pylon saddle to the anchor, wind tunnel tests were conducted using two sets of flexible models with different scaling ratios and one set of rigid segmental models. The effects of center-to-center spacings between upstream and downstream cables, wind angle of attack, and turbulence intensity on WIV of the model cables are examined. The effectiveness of rigid connectors on suppressing the WIV of the model cables was also evaluated. The findings indicate that the tandem cables with variable center-to-center spacings are susceptible to severe WIV in both smooth flow and turbulence flow. The vibration amplitudes and dominant modes change with the wind speed and wind attack angle. The occurrence of WIV in tandem cables with variable center-to-center spacings depends on the small spacings between the upstream and downstream cables, while large spacings affect the critical wind speed for WIV. Contrary to expectations, rigid connectors were found to amplify the WIV response in specific condition, emphasizing the importance of evaluating such mitigation strategies in bridge design stage.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"337 ","pages":"Article 120495"},"PeriodicalIF":5.6,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144071680","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}

{"title":"FRP spiral strip-confined concrete circular columns with ECC jackets: Fire resistance and post-fire compressive behavior","authors":"G.M. Chen ,&nbsp;R.X. Gan ,&nbsp;J.J. Zhang ,&nbsp;W. Hou ,&nbsp;Y.X. Zhang","doi":"10.1016/j.engstruct.2025.120503","DOIUrl":"10.1016/j.engstruct.2025.120503","url":null,"abstract":"<div><div>The vulnerability of resin matrix to high temperatures has hindered the wider application of externally bonded (EB) fiber-reinforced polymer (FRP) strengthening systems. In response to this challenge, engineered cementitious composite (ECC) is expected to be a promising fire-resistive material for FRP-strengthened structures due to its good fire performance. Against this background, this study introduces an innovative approach by designing ECC as an external layer for EB FRP systems. A detailed heat transfer analysis and experimental program was conducted on FRP spiral strip-confined concrete (FSSCC) circular columns with and without ECC jackets after fire exposure, with the consideration of several test variables. The test results showed that the supplemental ECC jackets significantly enhanced the fire resistance of test specimens by maintaining the FRP temperatures far below the decomposition limit of resin matrix, and also improved their structural performance, including load-carrying capacity and ductility. Besides, a non-negligible size effect in terms of compressive strength and stress-strain behavior was noticed in the ECC-jacketed FSSCC specimens after fire exposure. These findings show the effectiveness of FSSCC columns with ECC jackets at elevated temperatures, providing a solid experimental foundation for advancing the fire-resistant, high-performance structural strengthening system.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"337 ","pages":"Article 120503"},"PeriodicalIF":5.6,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144071772","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}