Structures最新文献

{"title":"Assessing the impact of corrosion on the seismic performance of moderately ductile steel moment frames","authors":"Masoud Salimi Mozaffarabadi,&nbsp;Mohammad Hossein Razmkhah,&nbsp;Mohsen Gerami","doi":"10.1016/j.istruc.2025.109406","DOIUrl":"10.1016/j.istruc.2025.109406","url":null,"abstract":"<div><div>Atmospheric corrosion is an electrochemical process that deteriorates metals under harsh environmental conditions. In steel structures, corrosion incurs significant financial costs and negatively impacts structural safety. To assess the effect of corrosion on seismic performance, the structure is first analyzed dynamically, and the damage level is then evaluated based on performance criteria. In this study, the Incremental Dynamic Analysis (IDA) method was employed to investigate steel moment-resisting frames with moderate ductility. Three frame models with 3, 5, and 8 stories were analyzed, considering corrosion effects at 0, 20, and 50 years. The structures were modeled in OpenSEES software, and corrosion thickness was determined based on ISO 9223 and ISO 9224 standards. The performance levels of the steel frames were evaluated using the maximum inter-story drift ratio as defined in the HAZUS-MH MR5 standard. Based on the fragility curve results, the median probability of complete collapse for the three, five, and eight story structures increased by 4.93 %, 1.14 %, and 2.44 %, respectively, after 20 years of corrosion compared to the uncorroded cases. After 50 years, these probabilities increase to 8.21 %, 4.55 %, and 7.32 %, respectively, compared to the corrosion-free condition. Additionally, the percentage change in collapse probability for the 5-story frame compared to the 3-story frame is 21.34 %, 18.21 %, and 18.21 % in the 0th, 20th, and 50th years, respectively, while for the 8-story frame, the corresponding changes are 26.57 %, 24.65 %, and 25.85 %.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109406"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279531","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 and numerical investigation on flexural performance of non-prestressed concrete precast bottom slab with a removable section steel and three ribs","authors":"Ming Li,&nbsp;Jianan Zhang,&nbsp;Biao Song,&nbsp;Yifan Li","doi":"10.1016/j.istruc.2025.109441","DOIUrl":"10.1016/j.istruc.2025.109441","url":null,"abstract":"<div><div>Current methods for enhancing the bending stiffness of non-prestressed concrete precast bottom slabs are constrained by the limited height of reinforcing elements, restricting their use to spans of up to 3.6 m. This study introduces the NPS-3R, an innovative precast bottom slab design that incorporates precast concrete segmental ribs and removable section steel. The design tackles common challenges such as insufficient bending stiffness and the reliance on temporary supports in large-span non-prestressed concrete precast bottom slabs (NLBS). To evaluate the bending behavior of the NPS-3R design, three full-scale precast bottom slab specimens were fabricated and subjected to static loading tests. These tests were complemented by detailed finite element (FE) simulations to analyze the stress distribution, deformation characteristics, and the interaction between the section steel and segmental ribs, providing a comprehensive understanding of the slab's flexural performance under varying loading conditions. Experimental results reveal a notable enhancement in flexural performance, with the cracking load and ultimate bearing capacity increasing by 78.9 % and 72.6 %, respectively, compared to NLBS. Although the addition of steel trusses has a limited effect on the overall bending behavior of NPS-3R, contributing only an 8.1 % increase in cracking load and a 3.9 % increase in ultimate load capacity, it significantly influences late-stage bending stiffness. The numerical model developed in this study shows high reliability, with stiffness errors in the load-mid-span deflection curves remaining below 10 % compared to experimental values. Simulation results further reveal that the length of short ribs, the section steel, and the diameter of stressed reinforcement are key factors affecting NPS-3R's bending performance. Additionally, the improved bending stiffness calculation method, based on integral and superposition techniques, demonstrates high accuracy and provides a reference for engineering design. These findings offer valuable insights for the design and optimization of precast concrete structures, providing a promising solution for improving the performance of large-span bottom slabs in both practical applications and theoretical research.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109441"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270730","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":"Bond behavior between steel bar and coal gangue coarse aggregate concrete: Experimental and numerical investigation","authors":"Weiping Zhao ,&nbsp;Jialong Chen ,&nbsp;Binjian Ling ,&nbsp;Yang Xu ,&nbsp;Yaqi Li ,&nbsp;Jiaqi Bai","doi":"10.1016/j.istruc.2025.109430","DOIUrl":"10.1016/j.istruc.2025.109430","url":null,"abstract":"<div><div>Using coal gangue (CG) as coarse aggregate in concrete preparation has good economic and environmental benefits, thus the mechanical properties of CG coarse aggregate (CGCA) concrete and the structural performance of reinforced concrete members made of CGCA have been investigated in various studies. However, the research on the bond behavior of ribbed steel bar in CGCA concrete is very limited, which hinders the application of this CGCA concrete. Therefore, in this paper, 36 center pull-out specimens were tested with the parameters of concrete strength grade (C30, C40 and C55), CGCA replacement ratio (0 %, 30 %, 50 %, 70 % and 100 %), and rebar diameter (16 mm and 25 mm). The test results demonstrated that with the increase of CGCA replacement ratio, the failure mode of center pull-out specimen transformed from pull-out failure to splitting failure, and the bond strength decreased by 9.9–50.7 %. Based on the test results presented herein, a prediction model for the bond strength of reinforced CGCA concrete members was proposed and its accuracy was verified. Finally, a meso-scale finite element model of crescent-shaped steel bar and CGCA concrete was established, and its reliability was verified by comparing with the test results in this paper. On this basis, the failure mechanism of crescent-shaped steel bar and CGCA concrete under pull-out force was investigated.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109430"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279532","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":"Lateral seismic performance analysis of diamond-shaped pylon based on equivalent single-tower model","authors":"Chao Zhang ,&nbsp;Zhengpeng Zhang ,&nbsp;Zhichao Lai ,&nbsp;Xinxin Gao ,&nbsp;Jinjun Lin ,&nbsp;Youwei Liu","doi":"10.1016/j.istruc.2025.109413","DOIUrl":"10.1016/j.istruc.2025.109413","url":null,"abstract":"<div><div>To study the lateral elastic-plastic seismic performance and failure mechanism of diamond-shaped pylon in long span cable-stayed bridges under extreme seismic excitation, a typical long span cable-stayed bridge was taken as the prototype and its finite element model was established using SAP2000. According to the principle of self-weight effect, lateral stiffness and lateral mode equivalence, a simplified method of diamond-shaped pylon is proposed. The entire bridge model is simplified into an equivalent single-tower model. Two fiber finite element models were established in OpenSees. Comparative analyses of static characteristics and related results were conducted to assess the applicability of single-towers with different material property. The reliability of the models was verified by comparing quasi-static test results. A systematic investigation of the lateral seismic performance of diamond-shaped pylon was carried out at three hierarchical levels: the structure, cross-section, and material. The analysis identified the yielding sequence and damage mechanisms. An in-depth analysis of material damage in diamond-shaped pylon offers essential data to support the investigation of their failure mechanisms under severe seismic excitations. The analysis results reveal that the lower area of the middle crossbeam is the most vulnerable region in the diamond-shaped pylon. The failure mechanisms consist of tensile yielding of the steel reinforcement, subsequent cracking compressive strain in the concrete, and final concrete crushing failure.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109413"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270727","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":"Beams unlock large carbon savings in reinforced concrete structures","authors":"Fernanda Belizario-Silva ,&nbsp;Matheus Carvalho ,&nbsp;Gustavo Fortes ,&nbsp;Cassio Gomes de Oliveira ,&nbsp;Leila Cristina Meneghetti ,&nbsp;Vanderley M. John ,&nbsp;Ricardo Leopoldo e Silva França","doi":"10.1016/j.istruc.2025.109427","DOIUrl":"10.1016/j.istruc.2025.109427","url":null,"abstract":"<div><div>Reinforced concrete structures significantly contribute to buildings’ embodied carbon, with floor design optimisation being crucial for material efficiency and structural decarbonisation. This study evaluates the embodied carbon, material use, cost, and labour intensity of seven cast-in-place reinforced concrete floor systems for a hypothetical four-story building in Brazil, considering four different column spans. The primary difference among the floor systems is the number of beams used. Results show a 3.4-fold variation in the embodied carbon intensity among the 28 alternatives, ranging from 48 to 167 kg CO₂/m². Beam-supported floors have lower material intensity and embodied carbon, while flat slabs perform worse, especially for larger spans due to post-tensioning requirements. Despite higher formwork complexity, floor systems with more beams remain cost-competitive due to material savings, demonstrating that low-carbon and low-cost designs can coexist. This study encourages structural designers to prioritise material-efficient solutions for decarbonising reinforced concrete structures. It shows that substantial savings can be achieved with current technology, offering practical ways to reduce buildings’ environmental impact while ensuring economic feasibility.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109427"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279538","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 of the critical collapse behaviour of stiffened box girders under impact bending load","authors":"Guijie Shi ,&nbsp;Deyu Wang ,&nbsp;Fuhua Wang","doi":"10.1016/j.istruc.2025.109440","DOIUrl":"10.1016/j.istruc.2025.109440","url":null,"abstract":"<div><div>For steel thin-walled girders, the loading capacity and failure modes under impact bending load will be significantly different from the static load condition. Critical collapse states, when collapse occurs, are difficult to pinpoint due to the extremely short duration of the impact load and the steady increase in structural deformation. The critical collapse state of the box girders under impact loading should be defined considering the progressive failure process of yielding or buckling from the expansion of local structural members into global regions. In this paper, seven impact experiments were conducted using a drop hammer facility to investigate the failure mechanism and dynamic capacity of the box girders under the impact bending. Three identical girders, fabricated using the same material and welding process, were designed. Seven impact cases were performed, each with varying impact velocities, to measure hammer acceleration, structural strain, and structural displacement. For a smooth transition from intact to collapsed girder in tests, replace it once major plastic deformation occurs. The experimental results were used to obtain the curves of impact load and structural dynamic response. Numerical studies were conducted using the finite element method (FEM) to investigate the dynamic response of girders under various impact velocities, and the results were compared with the experimental results. The critical collapse state of the girder under impact bending was determined. Based on the FEM results for the additional girders of various scantlings, the critical impact velocity of the girders is shown to be related to the cross-section properties. These conclusions are useful for assessing the safety of the box girders under impact bending loads.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109440"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270729","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":"Durability and impact performance of concrete beam coated with polyurea","authors":"Luis Mercedes,&nbsp;Arnau Viella,&nbsp;Ernest Bernat-Maso,&nbsp;Lluis Gil","doi":"10.1016/j.istruc.2025.109401","DOIUrl":"10.1016/j.istruc.2025.109401","url":null,"abstract":"<div><div>Polyurea, a versatile and highly durable elastomeric coating, has gained attention in recent years for its potential to enhance the ductility and strength of concrete structures. This study investigates the durability of polyurea-coated prestressed concrete beams under accelerated aging conditions (chloride-induced corrosion), followed by bending and impact testing to evaluate the mechanical effects of the polyurea coating. Results demonstrate that polyurea significantly enhances load capacity, ductility, and resilience against corrosion, effectively protecting structural integrity over time. Specifically, coated beams show a 16 % improvement in maximum load and an 81 % increase in deflection, while uncoated beams experience notable degradation due to corrosion. In impact tests, polyurea-coated beams absorb forces more effectively, showing reduced peak loads, minimized structural damage, and greater post-impact recovery, with a coefficient of restitution of 41–61 % for the uncoated beams and 71–77 % for the polyurea-coated beams. These benefits make polyurea a coating material, capable of extending the lifespan of concrete structures in corrosive and impact-prone environments.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109401"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279619","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 grouted sleeve splice with horizontal grouting defect after exposure to high temperature","authors":"Qingtao Li ,&nbsp;Mei Yi ,&nbsp;Boxiang Zhang","doi":"10.1016/j.istruc.2025.109443","DOIUrl":"10.1016/j.istruc.2025.109443","url":null,"abstract":"<div><div>Grouted sleeve splice is an important part of prefabricated concrete components. The performance and reliability of structures are directly impacted by the grouted sleeve splice between the steel bar and grouted sleeves. After exposure to high temperatures, the horizontal grouting defects are of great significance in terms of the mechanical properties of grouted sleeve splices. The mechanical properties of grouted sleeve splices at five horizontal grouting defect rates (0, 10, 15, 20, 25 and 30 %) after being exposed to four kinds of temperatures (room temperature, 200, 400 and 600 °C) were analyzed. The defect rate refers to the mass of missing grout within the grouted sleeve as a percentage of the grout mass in a fully grouted sleeve. The findings demonstrated that rebar fracture and rebar pull-out were the main causes of the failure of the grouted sleeve splice. Only the grouted sleeve splice with defect rate of 30 % exhibited the rebar pull-out failure under room temperature. The compressive strength of the grout gradually decreased with increasing temperature. After exposure to 600 °C, the strength had declined by approximately 50 % compared to ambient conditions. After exposure to 600 °C, the mechanical properties of rebars began to degrade, and the yield strength and ultimate strength of rebars decreased by 6.1 % and 5.9 % respectively compared with normal temperature. Furthermore, for the specimens with a defect rate of 10 %, the failure mode shifted from rebar fracture to rebar pull-out as the temperature rose to 600 ℃. The drastic decline in ultimate load of the grouted sleeve splice led to a significant reduction in ultimate slippage.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109443"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270726","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 and seismic analysis of a novel ring spring vertical isolation bearing with central ring","authors":"Heng Yang ,&nbsp;Gaozhen Wu ,&nbsp;Yuhong Ma ,&nbsp;Guifeng Zhao ,&nbsp;Wei Liu ,&nbsp;Haoming Huang ,&nbsp;Zhenyu Yang ,&nbsp;Jian Wang ,&nbsp;Lipeng Liu","doi":"10.1016/j.istruc.2025.109424","DOIUrl":"10.1016/j.istruc.2025.109424","url":null,"abstract":"<div><div>Recent seismic observations highlight the critical impact of vertical seismic actions on structural safety, especially in high-seismicity regions and near-fault zones, emphasizing the need for effective vertical isolation. However, current vertical isolation devices often face limitations in load-bearing capacity and energy dissipation. To address these challenges, this study introduces an innovative Ring Spring Vertical Isolation Bearing with Central Ring (RSVIB with CR) designed to enhance load capacity and energy dissipation performance. This study conducted a comprehensive investigation through theoretical modeling, experimental testing, and seismic response analysis. A mechanical model was developed to characterize the RSVIB with CR' s behavior during loading and unloading phases, with static compression tests validating the model and assessing energy dissipation.Parameter analysis revealed the influence of key geometric factors on stiffness and ultimate load capacity. Seismic response analysis demonstrated that the RSVIB with CR effectively reduces vertical peak accelerations and vibration amplitudes under diverse seismic inputs. Furthermore, its pronounced hysteresis behavior under large displacements highlights exceptional energy dissipation capacity, ensuring adaptability to intense seismic conditions. These findings establish the RSVIB with CR as an innovative and efficient solution for vertical isolation, enhancing seismic resilience in high-seismicity environments.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109424"},"PeriodicalIF":3.9,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270731","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":"Corrosion performance and strain behavior of reinforced concrete: Effect of natural pozzolan as partial substitute for microsilica in concrete mixtures","authors":"Ehsan Hosseinzadehfard ,&nbsp;Behnam Mobaraki","doi":"10.1016/j.istruc.2025.109397","DOIUrl":"10.1016/j.istruc.2025.109397","url":null,"abstract":"<div><div>Reinforced-concrete structures in southern Iran are susceptible to chloride-ion-induced corrosion, thus necessitating measures to reduce concrete permeability and protect embedded steel reinforcements. Microsilica is conventionally added at a cement weight of 8 % to enhance durability. In a recent investigation, the authors developed an innovative concrete mix design that replaces microsilica with natural pozzolan while ensuring compliance with the stringent durability and strength requirements stipulated by the construction industry. The current study advances the abovementioned investigation by precisely examining the corrosion performance of steel reinforcements in concrete beams constructed using eight mix designs proposed earlier. Sixteen beams are prepared and subjected to 60 d of accelerated corrosion using 5 % sodium-chloride solution and an impressed current to mimic harsh environments. Transverse strains are recorded every 10 d to assess deformation related to reinforcement corrosion. Subsequently, the beams are deconstructed to measure the rebar corrosion rates. The results indicate that the mix design containing 4 % microsilica and 12.5 % pozzolan exhibit corrosion levels almost identical to those of the control mix with 8 % microsilica, i.e., 8.9 % and 8.1 %, respectively. Further analysis shows a clear relationship between the transverse strain and the corrosion rate, with higher corrosion resulting in greater strain. Mixes containing more than 25 % pozzolan content experience significant bidirectional transverse strains, which is attributable to the accumulation of internal pressure inside the beam due to corrosion products.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"79 ","pages":"Article 109397"},"PeriodicalIF":3.9,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270722","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}