Structures最新文献

{"title":"Optimizing fracture resistance in steel fiber-reinforced self-consolidating concrete: Insights from mode II and mode I fracture energy analysis","authors":"Majid Ghomian ,&nbsp;Mehdi Dehestani ,&nbsp;Sajad Garshasbi ,&nbsp;Nima Azimi","doi":"10.1016/j.istruc.2025.108707","DOIUrl":"10.1016/j.istruc.2025.108707","url":null,"abstract":"<div><div>Fracture behavior in concrete is critical for structural integrity, especially under shear-dominated loading conditions where mode II fracture prevails. The present investigation examines the fracture resistance of self-consolidating concrete (SCC) reinforced with steel fibers, with a focus on analyzing both Mode II and Mode I fracture energies. Using the Bažant size effect method, the study explores how compressive strength, fiber content, and specimen size influence the fracture behavior of SCC. The results demonstrate that Mode II fracture energy increases significantly with both compressive strength and fiber content. A pronounced size effect is observed, particularly in larger specimens, where the influence of shear becomes more evident. Even a small addition of 0.3 % fiber volume notably enhances mode I fracture energy by 60 %, while higher fiber volumes affect fracture behavior depending on specimen size. Mode II fracture energy in SCC is found to be over 20 times greater than mode I, although this ratio decreases as fiber content rises. Notably, SCC with or without fibers exhibits lower mode II fracture energy compared to conventional concrete, highlighting the unique challenges and behaviors of fiber-reinforced SCC under shear stress. This investigation provides valuable insights into optimizing fiber content to improve both shear and tensile fracture resistance in SCC.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108707"},"PeriodicalIF":3.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684246","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 in-plane shear performance of precast concrete slabs with wide and narrow joints","authors":"Baoxi Song ,&nbsp;Shoutan Song ,&nbsp;Zhenying Liao ,&nbsp;Chun-Lin Wang","doi":"10.1016/j.istruc.2025.108680","DOIUrl":"10.1016/j.istruc.2025.108680","url":null,"abstract":"<div><div>The precast concrete slab (PCS) is an important element for transmitting shear forces in precast concrete frames. In this paper, in-plane shear tests of a widely jointed slab (WJS), narrowly jointed slab (NJS), and cast-in-place slab (CIPS) were carried out, and the failure modes and internal force transfer mechanisms of the specimens were analysed. The results indicate that the bearing capacities of WJSs and NJSs can be calculated based on CIPSs of equal thickness and post-cast layer thickness, respectively, and the initial stiffness is 0.9 times that of the corresponding CIPSs. The failure mode of all three specimens was diagonal concrete crushing failure, and bending cracks preceded diagonal cracks in each specimen. The bending cracks in the PCSs were mainly concentrated at the joint gaps of the new and old concrete. When the specimens failed, the precast layer of the WJS was well bonded to the post-cast layer, while the precast base slab of the NJS was detached from the post-cast layer. A comparison of the calculated results of the code methods and strut-and-tie methods with the test results suggested that the design of the shear capacity of slabs can adopt the strut-and-tie method in the ACI 318–19 code.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108680"},"PeriodicalIF":3.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684232","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":"Buckling behavior and design of cold-formed thin-walled steel storage rack upright frames","authors":"Liusi Dai ,&nbsp;Yu Chen ,&nbsp;Liang Cheng ,&nbsp;Chong Ren","doi":"10.1016/j.istruc.2025.108685","DOIUrl":"10.1016/j.istruc.2025.108685","url":null,"abstract":"<div><div>This study presents an experimental and numerical investigation on the buckling behavior of cold-formed thin-walled steel storage rack upright frames. A total of twelve component tests were performed to examine the ultimate loads, failure modes, and load-displacement curves of upright frames subject to compressive loading conditions. In the test, the failure modes observed were global buckling (GB) and distortional-global buckling interaction (DB+GB). The accuracy of numerical models for upright frames was confirmed by the experimental results. Parametric analyses were then conducted, considering variations in upright cross-sections, lengths, thicknesses, steel grades, brace sections, and span lengths. In particular, the differences between flexural buckling (FB) and flexural-torsional buckling (FTB) in upright frames with identical geometric configurations but different boundary conditions were compared. The findings indicate that, when all other conditions remain constant, releasing the out-of-plane rotational restraints on the loading side results in a 20–40 % reduction on the ultimate capacity. The relationship between load-bearing capacity of upright frames and single uprights was also analyzed, and the influence of various upright and brace configurations on the ultimate loads was investigated. Additionally, the applicability of the direct strength method (DSM) for predicting the ultimate capacity of upright frames was assessed. The results show that while the current global buckling DSM curve accurately predicts the ultimate load, the existing distortional buckling DSM curve is inadequate for upright frames that fail for DB+GB. Therefore, a modified distortional buckling DSM curve that accounts for buckling interactions is proposed.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108685"},"PeriodicalIF":3.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684233","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 framework for condition assessment of communication tower with inspection data in Heilongjiang Province, China","authors":"Jing Zhang ,&nbsp;Miaoying Li ,&nbsp;Jingyuan Zhang ,&nbsp;Yangyang Yu ,&nbsp;Hongbo Liu ,&nbsp;Hongshuai Gao","doi":"10.1016/j.istruc.2025.108710","DOIUrl":"10.1016/j.istruc.2025.108710","url":null,"abstract":"<div><div>Communication towers are the core equipment supporting mobile communication networks, and their security is crucial for the stable operation of communication systems. Assessing the condition of existing structures is a valuable approach to determining the extent of damage and formulating appropriate maintenance strategies. This article proposes a reasonable condition assessment framework to ensure the reliability of the communication tower and the timely repair of structural damage. The framework is based on site inspection data, with tower components as the smallest assessment units. The overall tower score is calculated in a hierarchical and graded manner. The Analytic Hierarchy Process (AHP) was used to calculate the weights of various tower components and parts, and health codes and color codes corresponding to the six condition levels of communication towers were introduced. Applying the proposed framework, the condition assessment of 1187 communication towers in Heilongjiang Province, China, demonstrates its successful application to various types of communication towers. The assessment results indicate that 1140 (96.0 %) communication towers are in qualified condition, while 47 (4.0 %) are in unqualified condition, implying that the majority of the communication towers in the region are in good condition. This study provides a new idea for using site inspection data to assess the condition of communication towers and make effective decisions about maintenance work.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108710"},"PeriodicalIF":3.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684248","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":"Structural seismic design using hybrid machine learning and multi-objectives Particle swarm optimization algorithm: Case of Special moment frames in a high seismic zone","authors":"Benbokhari Abdellatif ,&nbsp;Chikh Benazouz ,&nbsp;Mebarki Ahmed ,&nbsp;Mechaala Abdelmounaim","doi":"10.1016/j.istruc.2025.108441","DOIUrl":"10.1016/j.istruc.2025.108441","url":null,"abstract":"<div><div>The paper introduces a new methodology based on artificial intelligence (AI) techniques, including machine learning (ML) and multi-objective optimization (MOO), to design special moment frames (SMFs). The methodology aims to identify the optimal design concerning processing time, initial cost, fragility assessment, damage rate, and performance level. It provides a rapid alternative to create more resilient structures and simplify the design process. The methodology consists of two main components: a precise ML model that replaces the nonlinear time history analysis (NLTHA) and MOO algorithm to identify the Pareto frontier. This paper employs a hybrid ML model to predict seismic response regarding maximum Inter-story drift ratio (MIDR) to improve seismic prediction and enhance the generalization of the model. The proposed methodology will be applied to three SMFs with different heights (4-, 8-, and 12-stories), and the results will be compared to traditional force-based design (FBD). The results indicate that the proposed AI-based methodology achieved the desired performance, lower initial cost, and lower damage rate than the FBD designs. The AI-based methodology offers a fast alternative to performance-based design, resulting in structures that are more efficient in terms of performance and more cost-effective with reduced damage in high seismic zones.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108441"},"PeriodicalIF":3.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684150","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 investigation on seismic behavior of steel reinforced concrete transfer structure with lapping columns","authors":"Chao Yang ,&nbsp;Hui-Bin Ge ,&nbsp;Wenhao Pan ,&nbsp;Wanghai Luo ,&nbsp;Yaozhi Luo ,&nbsp;Yanfeng Zheng","doi":"10.1016/j.istruc.2025.108691","DOIUrl":"10.1016/j.istruc.2025.108691","url":null,"abstract":"<div><div>Transfer structures are commonly employed in high-rise buildings to redistribute loads from non-aligned upper floors to the structural system below. In this study, a steel-reinforced concrete transfer structure with lapping columns was implemented to address vertical structural discontinuities in the design of a mountain-shaped facade. An experimental program was conducted to evaluate the seismic performance of the proposed transfer structure under cyclic loading. Experimental results were compared with numerical simulations to assess their accuracy. The findings demonstrated that the transfer structure with lapping columns exhibited favorable seismic performance, providing adequate safety redundancy when subjected to seismic loads. Furthermore, the test specimen successfully met the design criterion of a strong-column weak-beam system. The numerical simulation showed good agreement with the experimental data, particularly in the backbone curve. Parametric study results indicated that the axial compression ratio and the volumetric hoop ratio were adopted appropriately for the engineering practice. This study provides valuable insights for the design and optimization of transfer structures with lapping columns in high-rise buildings.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108691"},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684251","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 and stress-strain relationship of steel fiber reinforced geopolymer recycled concrete","authors":"Yuan Wen,&nbsp;Xi Liu,&nbsp;Guangyu Sun,&nbsp;Wenshuo Shen","doi":"10.1016/j.istruc.2025.108697","DOIUrl":"10.1016/j.istruc.2025.108697","url":null,"abstract":"<div><div>Steel fiber reinforced geopolymer recycled concrete (SFGRC) is a low-carbon concrete material which can reduce the consumption of cement and natural aggregate, and alleviate construction and industrial waste accumulation problems. In this experiment, SFGRC was prepared using fly ash, ground granulated blast slag, silica fume, recycled coarse and fine aggregates, and hooked-end steel fibers. The effects of different calcium-silicon ratios, recycled aggregate volume content, steel fiber volume content, alkaline activator modulus, and alkali-cementitious ratio on the physical properties, mechanical properties, and stress-strain relationship of SFGRC were studied. The failure mode and crack development path of SFGRC were obtained. The stress-strain curve of SFGRC was studied, and the characteristic points of the curve were analyzed. Calculation models for the elastic modulus, peak stress, and peak strain of SFGRC were proposed. Based on the classical constitutive model, a two - stage constitutive model for SFGRC considering the damage evolution process was proposed. The microscopic morphology and formation mechanism of SFGRC were studied using XRD, SEM, and EDS techniques. The results show that the slump of SFGRC is 121 mm - 207 mm, the final setting time is less than 65 min, and the dry apparent density is less than 2040 kg/m³. Compared with ordinary concrete, SFGRC has the characteristics of lightweight, fast setting time, and early strength. The increase in the alkali and calcium content in the mixture can improve the mechanical properties of SFGRC, while the increase in the alkaline activator modulus and recycled aggregate volume content will reduce the mechanical properties of SFGRC. With the increase in the content of steel fibers, the tensile strength and flexural strength of SFGRC increase significantly, while the compressive strength first increases and then decreases. The failure process of SFGRC under uniaxial compression includes four stages. The two-stage constitutive model proposed by considering different factors in the ascending and descending sections of the stress-strain curve can better predict the uniaxial compression behavior of SFGRC, providing a theoretical basis for finite element analysis and structural design in practical engineering.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108697"},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684253","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":"Numerical analysis on the tensile behavior of innovative SC wall-RC foundation connections","authors":"Tianyu Liao ,&nbsp;Ying Wang ,&nbsp;Yuxing Yang ,&nbsp;Rong Chen ,&nbsp;Junbo Zuo ,&nbsp;Wenbing Han","doi":"10.1016/j.istruc.2025.108684","DOIUrl":"10.1016/j.istruc.2025.108684","url":null,"abstract":"<div><div>The problems of conventional lap-spliced connection are long splicing length, narrow internal space and difficulty in maintaining verticality. Therefore, an innovative connection was proposed by adopting tubes instead of vertical rebars. The innovative connection can not only solve the listed limitations, but also optimize the mechanical behavior and the construction efficiency. This paper numerically investigated the axial tensile performance of the innovative connection based on the previous tests. The force-transferring mechanism was revealed and the parametric study was conducted by changing concrete strength, plate thickness, eccentricity, number of studs, and location of shear connectors. The simulation results indicated that the steel plate in the tension zone yielded along the X-shaped tension band. The axial tension was transferred through the concrete compression struts generated under the combined action of concrete, tie bars and studs. The influence of concrete strength on the axial tensile performance was relatively small. The influence of number of studs, location of shear connectors, plate thickness, and eccentricity on the axial strength and stiffness was significant. Besides, current specifications were evaluated and detailed design recommendations were given.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108684"},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684138","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 seismic performance of precast bridge piers with corrosion-damaged grouted sleeve connections","authors":"Xiangtong Wu ,&nbsp;Wenting Yuan ,&nbsp;Anxin Guo","doi":"10.1016/j.istruc.2025.108699","DOIUrl":"10.1016/j.istruc.2025.108699","url":null,"abstract":"<div><div>Grouted sleeves are widely used in precast concrete (PC) structures because of their convenience in connecting precast elements. Although the seismic performance of PC structures has been investigated extensively, relatively few studies have focused on the behavior of bridges with grouted sleeves exposed to corrosive environments. Research that specifically examines the effect of corrosion in sleeves on the seismic performance of bridge piers is limited. This study aimed to address this gap by investigating the seismic performance of three PC bridge piers under quasi-static loading. Two of the piers incorporated grouted sleeves and were subjected to accelerated corrosion prior to pier construction, with target corrosion ratios of 20 % and 40 %. The third pier with uncorroded grouted sleeves served as the reference specimen. The main variable in this study was the corrosion ratio of the sleeves. The test results indicated that increasing the corrosion ratio in the grouted sleeves significantly reduced the seismic performance of the pier, particularly in terms of load-bearing capacity, ductility, stiffness, and energy dissipation capacity. These findings highlight the critical influence of sleeve corrosion on the seismic performance of PC bridge piers.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108699"},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684254","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":"Machine learning approach for predicting the compressive strength of ultra-high performance fiber reinforced concrete (UHPFRC)","authors":"S. Wijesundara,&nbsp;K. Wijesundara,&nbsp;S. Bandara","doi":"10.1016/j.istruc.2025.108704","DOIUrl":"10.1016/j.istruc.2025.108704","url":null,"abstract":"<div><div>Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) is an advanced cementitious composite which contains fibers. UHPFRC possesses improved mechanical properties, durability, workability, fire resistance, abrasion resistance, and low permeability. As a result, it finds extensive applications in casting full-scale structural elements and for structural retrofitting purposes. This research focuses on predicting the compressive strength of UHPFRC by employing Machine Learning (ML) techniques. Initially, a comprehensive literature review was undertaken to extract mix design details from previous experimental studies and a database was developed with 200 data points. Seven ML models, including Support Vector Regressor, Decision Tree Regressor, Random Forest Regressor, Gradient Boosting Regressor, Light Gradient Boosting Regressor, Extreme Gradient Boosting Regressor, and Multi-Layer Perceptron Neural Network were constructed for the estimation of compressive strength. Ten input parameters representing different material properties were utilized by the models, while the output parameter was the compressive strength of UHPFRC. The models underwent performance evaluation through the computation of various performance evaluation parameters. Among these models, the XGBR model demonstrated the highest prediction accuracy with an R² value of 0.905 and MSE value of 69.48 and hence was selected for detailed analysis. Overall, boosting-based models outperformed the rest and the SVR model showed the least accuracy. Further, a SHAP (Shapley Additive Explanations) analysis was conducted to unveil the black box nature of the ML model and to provide more detailed interpretations. A feature importance analysis was undertaken based on mean absolute SHAP values to investigate the impact of each parameter on the performance of the material. In addition, guidelines for the utilization of material parameters were presented at the conclusion to achieve optimal compressive strength of UHPFRC and provide a practical framework for UHPFRC mix design.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"75 ","pages":"Article 108704"},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684344","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}